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[0001] This application claims priority from British Patent Application No. 0424049.5, filed Oct. 29, 2004, the entire contents of which are incorporated herein by reference. FIELD [0002] The present invention relates to a method of controlling a brushless DC motor. In particular, but not exclusively, it relates to a method of reducing current and voltage spikes generated during a commutation cycle. BACKGROUND [0003] Brushless DC motors are well known and are used in numerous applications. For example, brushless DC motors are commonly used to power fans, such as may be found within computers to cool components, are used in hard disk drives, CD players, and electric tools. A brushless DC motor typically includes a stator, comprising one or more windings (e.g. of wire) and a rotor comprising one or more permanent magnets. The rotor may, for example, comprise a ring magnet, or an annular array of magnets. The rotor may be arranged to rotate within the stator, or alternatively the rotor may be arranged to rotate around the outside of the stator. [0004] To operate a brushless DC motor, current is passed through the stator windings, and a magnetic field is generated which interacts with the rotor so as to cause relative rotation between the stator and the rotor. Rotor rotation is controlled by controlling the current in the or each, stator winding in an appropriate manner. In the case of single phase brushless DC motors, comprising a single phase stator winding, this control involves the repeated excitation of the winding with current first in one sense, and then in the opposite sense. In the case of multiple phase windings, rotation may be achieved by arranging for the windings of the different phases to be successively excited, in effect to produce a rotating magnetic field with which the rotor interacts. This control of current in the windings of a DC brushless motor to achieve rotor rotation is known as commutation, and in general involves a periodic switching of current from one current path through the winding(s) to another. This switching may comprise the reversal of current direction through a winding and/or the switching of current path from one winding to another. [0005] A further understanding of the operation of brushless DC motors will be obtained from the following discussion. [0006] In general, the field generated by the excitation of the stator windings may be considered to comprise one or more pairs of North and South poles. This generated field interacts with the magnetic rotor, with each rotor pole being attracted to opposing stator poles and repelled by similar stator poles. As the stator is held steady, the effect is that the rotor rotates with respect to the stator. The speed of rotation of the rotor may be readily varied by controlling the magnitude and the timing of the current passing through the stator. [0007] As the rotor rotates relative to the stator, opposite poles of the rotor and the stator are brought into alignment. In the case of single phase motors, it is then necessary to reverse the direction of current flow within the stator windings, such that the poles of the stator swap over, in order to allow the rotor to continue to rotate. As the rotor rotates yet further, the direction of current flow in the stator windings must be reversed yet again. Hence, for continued rotation, commutation of a single phase brushless DC motor comprises a periodic reversing of the direction of current flow through the stator windings. Thus, commutation is cyclical. [0008] For a single phase motor, a single commutation cycle comprises a first drive portion, in which current is driven through the windings in a first direction, and a second drive portion, in which current is driven through the windings in a second, opposite direction. In this case, the length of the full commutation cycle is defined as the interval between the beginning of one first drive portion and the beginning of the next first drive portion, or, equivalently, as twice the interval between successive changes in direction of the current flowing within the stator windings. [0009] For commutation to be effective, the motor must also comprise means for detecting the relative position of the rotor and the stator in order that the change in current direction occurs at the correct point to ensure continued rotation of the rotor. The position detection is typically achieved using a Hall effect magnetic sensor device (or a number of such devices), which generates an output signal indicative of the distance between the sensor and the nearest pole of the rotor. Other forms of rotor position detection may, of course, be used. [0010] A brushless DC motor is typically operated using a switching circuit, for supplying the current to the stator windings, and a controller to control the switching circuit. The switching circuit and/or the controller may be comprised in the motor itself, or may be separate items. For single phase brushless DC motors the switching circuit is typically an H-bridge circuit arranged between positive and negative (or ground) power supply rails. Winding current direction and timing is controlled by appropriate control of the switching elements within the H-bridge. The controller is typically fabricated as an integrated circuit, though may alternatively be formed from discrete components. The controller has inputs derived from the position detector (e.g. Hall sensor) to sense the position of the rotor, and control inputs to set parameters such as motor speed and direction. The controller has outputs, which supply switching signals to control the switching elements of the H-bridge. [0011] In prior art commutation methods, for single phase motors during the first drive portion of each commutation cycle an average voltage is applied across the stator windings (using PWM techniques, for example) in a first sense, causing a current to flow within the windings in a first direction. As the stator and rotor poles come close to alignment the drive portion ends and the applied voltage is removed, in effect to switch the current “off”. The timing of switch off is determined by the signal from the position detector. There may be a short commutation delay before the second drive portion, in which the same average voltage is applied across the stator windings (if constant rotor speed is required) but in the opposite sense. This causes a current to flow within the windings in the opposite direction. The commutation delay is to ensure that at the point at which the stator and rotor poles pass each other, substantially no current is flowing within the stator windings. This is important to ensure that slight inaccuracies in the timing of the commutation do not cause the motor to slow due to the stator and rotor poles being swapped too soon. The duration of the commutation cycle is equal to the sum of the durations of the first and second drive portions and the two commutation delays (i.e. the delay between the first and second drive portions of one cycle, and between the second drive portion of one cycle and the first drive portion of the next cycle). [0012] The average voltage may be applied across the stator windings in the first and in the second, opposite sense by determining which switching elements within the H-bridge are open and closed. During each commutation cycle, at each moment of current “switch off” (i.e. at the end of the first drive portion and at the end of the second drive portion) typically all switching elements within the H-bridge are opened to interrupt current flow from the supply rails through the stator windings. In other words, current drive to the windings is removed (i.e. it ceases). This switch state is maintained during the commutation delay. [0013] However, it will be appreciated that at these “switch off” points large currents are flowing through the windings. Thus, when all switches are opened (i.e. to remove the applied voltage) a large back EMF is generated (i.e. a large voltage spike is developed across the windings). This large voltage spike can in turn give rise to a large and undesirable current spike. The magnitudes of these voltage and current spikes may be many times greater than the average values of drive voltage and winding current experienced during each commutation cycle. [0014] The problem of the large back EMF and the consequent current spike is exacerbated by the fact that even when the average voltage applied across the stator windings is constant during a drive portion of the commutation cycle, the current within the stator windings tends to rise towards the end of the drive portion of the commutation cycle. This rise in the stator current is due to the change in the inductance of the stator windings associated with the changing relative position of the rotor. [0015] These large voltage and current spikes induce vibration in the motor as the stator windings and the rotor magnets vibrate in sympathy with the changes in energy. This vibration causes audible clicks, which is usually undesirable. Additionally, electrical noise may be generated on the motor voltage supply that can be damaging to other equipment, such as CPUs that share the same power supply. In certain arrangements, the electrical noise on the voltage supply is a result of current passing through the parasitic body diodes of the transistors that form the switching elements (or any external diodes present) within the switching circuit. These body diodes act as charge pumps, raising the voltage on the supply rail temporarily higher than its normal level. In order to prevent the voltage spike on the supply rail from damaging connected equipment it is known to isolate the brushless DC motor via a blocking diode, arranged on the positive power supply rail, such that current may flow from the power supply network to that part of the supply rail local to the motor, but not in the reverse direction during locally generated voltage spikes. [0016] The size of the current and voltage spikes at the switching points in the commutation cycle are dependent on the magnitude of winding current at these points. They are, therefore, partly dependent upon the timing of these switch-off points. If current switch-off is done earlier in the cycle, i.e. when the poles of the rotor and the stator are further apart, then the sizes of the spikes can be reduced. This is because, as described above, the stator current tends to rise towards the end of the drive portion of the commutation cycle due to inductance change caused by the changing position of the rotor relative to the stator. By switching off earlier, excessive rises in winding current can be avoided. The switch-off timing (i.e. the timing of the removal of the applied voltage) may conveniently be varied by moving the position of a Hall sensor, arranged to detect rotor position, around the circumference of the stator. [0017] However, removing the applied voltage earlier necessarily results in an increase in the commutation delay, otherwise the stator poles will be switched over before the rotor poles have passed causing rotation of the rotor to be resisted. If this occurs the motor may slow or even stop due to the rotor not having sufficient inertia to rotate past the position in which the poles are aligned. A side effect of increasing the commutation delay is that the proportion of time during each commutation cycle for which the motor is not being powered is increased, resulting in a decrease in speed, which must be counteracted by supply of a greater current to the stator windings throughout the rest of the cycle. Additionally, the rate of rotation of the rotor will vary in an uncontrolled manner throughout each commutation cycle. [0018] The large current and voltage spikes may also physically damage motor components, in particular the switching elements. A known technique to address this problem of large currents and voltages is to use components having higher voltage and current ratings than the maximum expected peak values at the end of the drive portion(s) of each commutation cycle. However, these components, notably transistors, are therefore rated for significantly higher voltages and currents than is required for the remainder of the commutation cycle. It is undesirable to use over specified transistors as the internal resistance loss is increased by the use of higher voltage components, which therefore leads to energy being wasted. Additionally, the cost of electronic components typically increases as the voltage and current ratings increase, resulting in a more expensive motor. [0019] The torque generated within a brushless DC motor is inversely proportional to the square of the distance between opposing poles of the rotor and the stator. Additionally, the torque is proportional to the size of the current passing through the stator windings, as this affects the magnitude of magnetic flux density generated within the electromagnet. Towards the end of each drive portion of each commutation cycle, when the winding current rises due to inductance change as discussed above, the opposing poles of the rotor and the stator come close together. Consequently, this winding current rise generates little torque, and may therefore be considered to be wasted energy. [0020] The current spike due to the back EMF may also be considered to be wasted energy. A partial solution to the problem of wasted energy is to provide a large capacitor across the voltage supply to the H-bridge, such that at the end of each drive portion of the commutation cycle when the back EMF of the coil creates a large voltage spike across the capacitor this excess voltage charges up the capacitor, storing energy to help power the next commutation cycle. However, using a capacitor to store electrical energy is inefficient because in order to charge the capacitor the charge current must pass through the body diodes of the transistors forming the switching elements (or external diodes if these are present). It is preferable not to have to try to recover this energy in the first place. Additionally, due to the large value capacitance required the capacitor may be physically large. There may not be physical space within a motor housing for the capacitor. Consequently, the result is a compromise between a medium sized capacitor and accepting some voltage spike on the voltage supply to the H-bridge, necessitating some over specifying of components. Also, this approach does not have any impact on the problems of over specified components and acoustic/electrical noise as described above. [0021] When the supply voltage is applied across the stator windings at the beginning of each drive portion of each commutation cycle the current flowing through the coil builds steadily to an early peak. This gradual rise is due to the inductance of the stator windings. The motor is most efficient during the early part of each drive portion as the opposing stator and rotor poles are further apart. Consequently, this early peak represents the most efficient part of the commutation cycle. [0022] A further known method of reducing the size of the voltage and current spikes at the end of each drive portion of the commutation cycle is to limit the maximum current that may flow through the stator windings. This has the effect of flattening the current profile throughout the whole drive portion. However, while this method does remove the worst effects of the voltage and current spikes in terms of noise and damage to components, this method is inefficient. The unwanted current spike cannot be limited to a current level lower than the pulse at the beginning of each drive portion without unduly limiting that part of the cycle also. Therefore, the best that can be achieved with this approach is a slight flattening of the current waveform over the whole of the commutation cycle. As discussed above, the early part of the drive portion of the commutation cycle, when the like poles are closest together, provides the greatest torque for a given current passing through the stator windings. Therefore, it is desirable not to limit the current flow during the early part of the commutation cycle, whilst addressing the problem of voltage and current spikes generated at the ends of the drive portions of the commutation cycle. This cannot be achieved with basic current limiting techniques. SUMMARY [0023] It is an object of the present invention to obviate, or mitigate, one or more of the problems described above. [0024] According to a first aspect of the present invention there is provided a method of controlling a brushless DC motor of the type having a stator, comprising a stator winding excitable to generate a stator magnetic field, and a rotor, arranged to rotate with respect to the stator and comprising permanently magnetised material arranged to generate a rotor magnetic field to interact with the stator magnetic field to produce rotation of the rotor, the method comprising the steps of: [0025] driving current through the stator winding to generate a stator magnetic field to interact with the rotor magnetic field; [0026] detecting rotor position with respect to the stator; and [0027] cyclically commutating the stator winding current according to rotor position as the rotor rotates, each commutation cycle including a drive portion during which current is driven through the stator winding in one sense and at the end of which the driving of current in said sense is ceased, [0028] wherein the method further comprises the steps of: [0029] during an initial portion of each drive portion, driving current through the winding such that the magnitude of the winding current increases; and [0030] during an end portion of each drive portion, actively reducing the magnitude of the winding current. [0031] The step of driving current during the initial portion may alternatively be described as a step of controlling current. Similarly, the step of actively reducing current during the end portion may be described as a step of controlling current. [0032] Thus, in a method in accordance with the present invention, during an end portion of each drive portion the magnitude of the winding current is actively reduced (i.e. its magnitude falls during this end portion) so as to reduce the eventual current magnitude at the end of the drive portion. The reduction is typically a progressive one. It may be a linear reduction, for example, or may take an alternative form. [0033] It should be noted that during the end portion of the drive portion, current is still being actively driven through the stator winding; the magnitude of the winding current is not falling because drive has ceased, rather as a result of appropriate change in the active drive (e.g. a reduction in a drive voltage). [0034] An advantage of the present invention is that by selectively reducing the current flowing within the stator windings towards the end of a drive portion of a commutation cycle, current and voltage spikes that in the past have been generated at the end of the drive portion may be avoided, or at least their magnitudes may be reduced without limiting the current flowing within the stator windings throughout the rest of the drive portion. [0035] Another advantage is that by actively reducing winding current at the end of a drive portion, the efficiency of the motor is increased. [0036] Yet another advantage is that the commutation delays can be reduced, thereby further improving motor efficiency. [0037] The end portion may immediately succeed the initial portion, or alternatively there may be another portion in between. During any such intermediate portion, winding current may be constant, or alternatively it may vary. For example, during an intermediate portion the winding current magnitude may decrease. This may be a passive reduction, resulting not from any change in current drive, but from a change in inductance as the position of the rotor changes with respect to the stator. [0038] The step of actively reducing may comprise reducing the magnitude of the winding current such that its value at the end of the drive portion is less than 30% of the average value of winding current magnitude during the drive portion. [0039] In certain preferred embodiments the magnitude of the winding current is reduced substantially to zero by the end of the drive portion. [0040] The step of driving current during the initial portion may comprise increasing the magnitude of winding current to a peak value during said initial portion, and the step of actively reducing may then comprise reducing the magnitude of the winding current below said peak value, for example to less than 30% of the peak value. [0041] In certain preferred embodiments, the method may comprise the step of controlling winding current during each drive portion such that the magnitude of the winding current increases from substantially zero, at the beginning of the initial portion, up to a peak value, and then decreases substantially continuously from said peak value throughout the remainder of the drive portion, to the end of the end portion. [0042] The method may also comprise the steps of detecting rotor speed and adjusting the length of the end portion, during which winding current is actively reduced, according to rotor speed. For example, this adjustment may comprise reducing the length of the end portion as rotor speed increases. [0043] In certain preferred embodiments the step of actively reducing further comprises the steps of generating a current reduction control signal indicative of the desired current reduction during the end portion from a signal indicative of the position of the rotor; and reducing the magnitude of the winding current in response to the current reduction control signal. The step of generating the current reduction control signal may comprise providing rotor position sensing means to provide the signal indicative of the position of the rotor. In certain embodiments, the rotor position sensing means is arranged to detect the rotor magnetic field and output a rotor position signal. The rotor position sensing means may conveniently comprise a Hall effect device providing a signal to an amplifier. The current reduction control signal may be derived using a method including integration of the Hall amplifier output and comparison with a saw tooth signal having a frequency equal to the commutation frequency. [0044] In certain preferred embodiments, the step of actively reducing the magnitude of the winding current comprises reducing a drive voltage applied across the winding. The drive voltage may be a PWM voltage, and the step of reducing the drive voltage applied across the winding may thus comprise reducing a duty cycle of the PWM voltage. [0045] Alternatively, or additionally, the step of actively reducing may comprise providing a component having a controllable variable resistance in series with the stator windings and increasing said variable resistance. The component may, for example, comprise a variable resistor, or a transistor having a variable resistance. [0046] The method may be used to run a brushless DC motor at constant speed. [0047] Another aspect of the invention provides control apparatus for a brushless DC motor, of the type comprising a stator, comprising a stator winding excitable to generate a stator magnetic field, and a rotor, arranged to rotate with respect to the stator and comprising permanently magnetised material arranged to generate a rotor magnetic field to interact with the stator magnetic field to produce rotation of the rotor, the control apparatus comprising: [0048] current drive means (a current drive) adapted to drive current through the stator winding to generate a stator magnetic field; [0049] rotor position detection means (a rotor position detector) adapted to provide a rotor position signal; and [0050] commutation means (commutation apparatus) adapted to cyclically commutate the stator winding current according to the rotor position signal as the rotor rotates, each commutation cycle including a drive portion in which the current drive means is adapted to drive current through the stator winding in one sense and at the end of which the current drive means is adapted to cease current drive; [0051] wherein the control apparatus further comprises means arranged to increase the current through the winding during an initial portion of each drive portion and means arranged to actively reduce the current through the winding during an end portion of each drive portion. [0052] The rotor position detection means in certain embodiments is arranged to detect the rotor magnetic field. [0053] The control apparatus may be arranged so as to implement one or more of the preferred features of the control method in accordance with the first aspect of the present invention. For example, the current drive means may be arranged to drive current through the stator winding by applying a PWM voltage across the winding, and the control apparatus may actively reduce the current through the winding during the end portion of each drive portion by reducing the duty cycle of the PWM voltage. [0054] Yet another aspect of the invention provides a method of controlling an actuator of the type having a stator, comprising a stator winding excitable to generate a stator magnetic field, and an armature, arranged to move with respect to the stator and comprising permanently magnetised material arranged to generate an armature magnetic field to interact with the stator magnetic field to produce movement of the armature, the method comprising the steps of: [0055] driving current through the winding to generate a stator magnetic field to interact with the armature magnetic field; [0056] detecting armature position with respect to the stator; and [0057] commutating the winding current according to armature position as the armature moves, the commutation including a drive portion during which current is driven through the winding in one sense and at the end of which the driving of current in said sense is ceased, [0058] wherein the method further comprises the steps of: [0059] during an initial portion of the drive portion, driving current through the winding such that the magnitude of the winding current increases; and [0060] during an end portion of the drive portion, actively reducing the magnitude of the winding current. [0061] Further objects, and advantages of the present invention will become apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS [0062] The present invention will now be described, by way of example only, with reference to the following drawings, in which: [0063] FIG. 1 schematically illustrates a conventional brushless DC motor, which may be controlled using a control method or control apparatus embodying the present invention; [0064] FIG. 2 illustrates the variation, with time, of current passing through the stator windings of a conventional brushless DC motor, controlled using a conventional commutation method; [0065] FIG. 3 illustrates voltage spikes created on a voltage supply to the brushless DC motor whose winding current is shown in FIG. 2 ; [0066] FIG. 4 schematically illustrates a conventional switching circuit and controller for a brushless DC motor, and which may be used in embodiments of the present invention; [0067] FIG. 5 schematically illustrates a modification to a controller for a brushless DC motor in accordance with an embodiment of the present invention; [0068] FIG. 6 illustrates the generation of a voltage waveform used to modulate the PWM signal in an embodiment of the invention; [0069] FIG. 7 illustrates the voltage waveform used to drive the H-bridge controlling current flowing through the stator windings, in an embodiment of the invention; [0070] FIG. 8 illustrates the current passing through the stator windings of a brushless DC motor, controlled using a method in accordance with the present invention; [0071] FIG. 9 illustrates the voltage on a supply to the brushless DC motor, whose winding current variation with time is shown in FIG. 8 ; and [0072] FIG. 10 illustrates another control circuit which may be used in embodiments of the invention to achieve active reduction in stator winding current towards the end of each drive portion. DETAILED DESCRIPTION [0073] Referring first to FIG. 1 , this schematically illustrates a conventional single phase brushless DC motor, comprising stator 1 and rotor 2 . This motor may be controlled using a control method or apparatus embodying the present invention, and may be combined with control apparatus in certain embodiments of the invention. Stator 1 comprises stator windings 3 , shown here as being wound around pole pieces such that when current passes through the windings 3 two pairs of North and South poles are created as shown. In other words, excitement of the stator windings generates a stator magnetic field. The rotor comprises permanently magnetised material arranged to generate a rotor magnetic field which interacts with the stator field to produce rotation. In certain embodiments, the rotor comprises one or more permanent magnets. In the present example, the rotor comprises a ring of magnets 6 having two pairs of poles as shown. The rotor 2 rotates about an axis passing through the centre of stator 1 . A Hall effect sensor 8 is arranged to detect the rotor position. Alternatively, stator windings 3 may be arranged in a ring around a central rotating rotor. [0074] In FIG. 1 , the motor is shown with the poles almost aligned. The rotor 2 is repelled by the poles of the stator 1 such that it rotates in the direction shown by 7 . As the rotor 2 rotates, such that opposite poles on the stator 1 and rotor 2 move into alignment the direction of current flow within the stator windings 3 reverses. This current reversal (a commutation) ensures that onward motion of the rotor 2 continues. [0075] Referring now to FIG. 2 , this illustrates the current passing through the stator windings 3 of a conventional single phase brushless DC motor, illustrating the problem of an increase in current towards the end of a drive portion of the commutation cycle. The current signal is plotted on the Y-axis against time on the X-axis. [0076] At time t 0 , a voltage supply is first applied across the stator windings 3 at the beginning of a drive portion of the commutation cycle. This gives rise to current flow. The current passing through the windings 3 builds rapidly to an initial peak at time t 1 . The current does not rise to its maximum value immediately due to the inductance of the stator windings 3 . As discussed in the introduction, it is during this early part of the commutation cycle that the motor is most efficient in terms of transferring energy from a stator windings 3 to the rotor 2 , i.e. converting electrical energy into kinetic energy. [0077] As the rotor turns, and the poles move apart, the current passing through the stator windings falls off slightly to a low at time t 2 . This is due to the interaction of the magnetic field generated by the current passing through the stator windings 3 and the magnetic field of the rotor 2 affecting the inductance of the stator windings 3 as the stator and rotor poles move apart. As the rotor 2 rotates further, bringing the rotor poles towards alignment with the similar poles on the stator windings 3 , the current starts to rise as the rotor magnets affect the inductance of the stator windings. [0078] The voltage applied across the stator windings is switched off at time t 3 , by which time winding current has risen to a peak 10 due to inductance change caused by the changing position of the rotor 2 relative to the stator 1 . By switching off when such a large current is flowing, a large back EMF is generated which can in turn generate a large current spike as described above. The winding current then drops back towards zero, and there is then a short commutation delay 11 before the next drive portion of the commutation cycle begins at time t 4 . After each drive portion 13 , the direction of current flowing through the stator windings 3 is reversed in order to ensure that the rotor 2 continues to rotate in the same direction. This is achieved by controlling the states of the switching elements within the H-bridge such that the supply voltage is applied across the stator windings in the opposite sense. However, it is convenient to measure the current passing through the stator windings 3 at the ground return of the switching circuit driving the stator windings. Consequently, the second drive portion of commutation cycle beginning at time t 4 is shown as also having a positive current, although it will be appreciated that within the stator windings 3 the current will be reversed. In other words, it will be appreciated that in FIG. 2 the variation of only the current magnitude with time is shown, not its sense. The winding current in the second drive portion of the cycle, beginning at t 4 , is in the opposite sense to that during the interval t 0 -t 3 . The current variation during the next drive portion has substantially the same profile as that in the first drive portion (t 0 -t 3 ) and hence the portion of FIG. 2 between t 0 and t 4 is indicative of winding current variation during the entire commutation cycle. Portion 13 is representative of each drive portion, portion 11 is representative of each commutation delay, and portion 12 is representative of half a commutation cycle. [0079] As discussed above in the introduction, the current spike 10 is inefficient at transferring energy to the rotation of the rotor 2 . The half commutation cycle 12 depicted in FIG. 2 is illustrative of the problem of current spikes for a brushless DC motor having a relatively large commutation delay 11 between consecutive drive portions. With a conventional brushless DC motor, conventionally commutated, there will always be some current spike towards the end of each drive portion. However by increasing the size of the commutation delay the spike may be partially reduced. This may be achieved by altering the position of the Hall sensor relative to the stator such that the current is terminated lower down the rising waveform. The current supply is turned off at time t 3 in order to reduce the size of the current spike. For other configurations of motor, the current spike may be significantly greater than the desired pulse at time t 1 towards the beginning of the commutation cycle 12 . Commutation delay 11 is necessary to ensure that the current is not supplied to the stator windings 3 before the stator and rotor poles have passed each other. [0080] The current spike 10 at the end of each drive portion of each commutation cycle also generates a voltage spike on the voltage supply due to the charge pump effect of the transistor body diodes (or alternatively any external diodes present) as discussed above in the introduction. FIG. 3 illustrates this effect. The normal voltage supply level 20 rises rapidly to peak 21 at the end of each drive portion of each commutation cycle at the time of the current peak 10 , before dropping back to the normal level 20 . [0081] The speed of a brushless DC motor may be varied by varying the voltage applied across the stator windings 3 using linear techniques such as a variable resistor or transistor in series with the coil. However, it is increasingly common to use Pulse Width Modulation (PWM) techniques to switch the current passing through the stator windings on and off at a high frequency during the drive portion 13 of the commutation cycle, i.e. between t 0 and t 3 . The average voltage applied across the stator windings during the drive portion is therefore lower than the peak voltage applied during each applied voltage pulse. Consequently, the average current within the coil is dependent upon the PWM duty cycle of the switching signal supplied to the H-bridge switching elements at any time. PWM serves to vary the amount of energy stored within the coil as magnetic flux. [0082] PWM operates by generating a very fast oscillating signal, typically for motor controllers at a frequency of around 25 kHz. This oscillating signal is then compared with a reference or control signal generating a pulsed output at the same frequency but with a variable duty cycle dependent upon the magnitude of the control signal. The duty cycle may vary between 100% (pulse signal always high) and 0% (pulse signal always low). The PWM signal may then be used to drive circuits, in this instance the stator windings 3 , such that the signal applied to the windings is either fully on or fully off, but the average current flowing through the coil is variable. Therefore, the speed of the motor may be varied by an externally generated control signal driving the PWM oscillator. [0083] FIG. 4 schematically illustrates a simplified known brushless DC motor controller 30 providing variable speed switching signals via PWM to switching circuit 31 . Controller 30 is depicted as being integrated onto a single chip, having a positive voltage supply V cc and a connection to ground 32 (or a connection to a negative voltage supply). [0084] Stator windings 3 are controlled by switching circuit 31 . The flow of current through the stator windings 3 is controlled by a H-bridge circuit 37 comprising transistors 38 , 39 , 40 and 41 which form the switching elements, voltage supply V cc and ground return 43 . The voltage supply V cc and ground return 43 for the switching circuit 31 may be the same as for the controller 30 , or they may differ, for instance if the motor is driving a large load and consequently needs a larger power supply. [0085] Current is allowed to pass through the stator windings 3 in a first direction by turning on transistors 38 and 41 and turning off transistors 39 and 40 . Current is allowed to pass through the stator windings 3 in a second opposite direction by turning on transistors 39 and 40 and turning off transistors 38 and 41 . The times at which transistors 38 , 39 , 40 , 41 are turned on and off are determined by the switching signals supplied to the gates of the transistors on lines 44 , 45 , 46 , 47 respectively. The switching signals are generated by the controller 30 . [0086] In this example, transistors 38 - 41 are MOSFETs. Transistors 38 and 39 are high side p-channel MOSFETs and transistors 40 and 41 are low side n-channel MOSFETs. The signals on lines 44 - 47 are applied to the gate of transistors 38 - 41 respectively. When the signal on line 44 or 45 is low transistor 38 or 39 conducts. When the signal on line 46 or 47 is high transistor 40 or 41 conducts. [0087] Transistors 38 and 39 should not be turned on at the same time. Similarly, transistors 40 and 41 should not be turned on at the same time. As described above, the current passing through stator windings 36 is conveniently measured at the ground return, i.e. at the point where the connections to transistors 40 and 41 and ground connection 43 meet. [0088] Controller 30 comprises a PWM modulator 33 having a speed control signal input 34 derived from speed control circuitry outside of the controller 30 . Input 34 is used to set the speed of the motor and may include feedback from the motor monitoring the speed of the motor. The means by which input 34 is derived may be entirely conventional, and as such will not be described further here. The output 35 from the PWM modulator 33 is a pulse width modulated switching signal having a duty cycle proportional to the level of input 34 . [0089] In certain embodiments of the invention the motor is controlled such that the rotor rotates at substantially constant speed with respect to the stator (in other words, the control is such that the average angular velocity of the rotor is substantially constant from one revolution, and hence from one full commutation cycle, to the next). Even though rotor speed is constant, winding current is actively reduced in the end portion of each drive portion of the commutation cycle. [0090] Thus, the motor may run at a constant speed, in which case input 34 is constant or may be omitted entirely. Additionally, further inputs to the pulse width modulator 33 may be included, such as current feedback to control the current at motor start up and under stall conditions. These additional inputs may be entirely conventional, and as such will not be described further here. [0091] PWM modulator switching signal output 35 is supplied to phase drive and control circuit 48 . Circuit 48 applies the PWM signal 35 to either line 46 or 47 , or neither, depending upon the signal supplied to circuit 48 by commutation control circuit 49 on control line 50 . Control circuit 49 additionally supplies a second control signal on control line 51 to phase drive circuit 52 . Phase drive circuit 52 switches transistors 38 and 39 on and off via signals supplied on lines 44 and 45 . [0092] Together phase drive and control circuit 48 and phase drive circuit 52 comprise the drive means for the controller. The result is that commutation control circuit 49 controls the time at which transistors 38 - 41 are switched on and off, and phase drive and control circuit 48 ensures that when transistors 40 and 41 are switched on the signal supplied to the gate of either transistor 40 or transistor 41 is the PWM signal supplied on line 35 . Therefore, the high side H-bridge switches 38 and 39 are used to provide commutation and determine the duration of the drive portion of the commutation cycle for the stator windings 36 , while low side H-bridge switches 40 and 41 provide commutation, timing of the drive portion and PWM speed control. In the alternative, the PWM speed control may be performed by the high side switches 38 and 39 , by supplying these with the PWM switching signal. [0093] Commutation control circuit 49 ensures that only transistor pairs 38 and 41 or 39 and 40 may be switched on at any one time, or alternatively that all transistors are switched off during the commutation delay 11 , or when the motor is disabled. PWM modulator 33 provides speed control to the motor by ensuring that the current supplied to stator windings 3 by H-bridge 37 is PWM modulated. [0094] Commutation control circuit 49 comprises one or more control inputs 53 . For instance there may be inputs to disable the motor and vary the commutation delay. [0095] Controller 30 further comprises inputs 54 and 55 from Hall Sensor 56 . Hall sensor 56 is used to detect the position of the rotor 2 relative to the stator 1 . Hall sensor 56 provides a differential signal to inputs 54 and 55 . In one embodiment, the Hall sensor may be a “naked” Hall sensor, which normally outputs half its supply voltage to each of its outputs. When a pole of the first orientation passes one output goes to a higher voltage and the other output goes to a lower voltage, and vice versa. In an alternative embodiment, the sensor may be a buffered Hall sensor, which provides a high or low signal on an output provided to either input 54 or 55 . The other input to Hall amplifier 57 is held halfway between the supply voltages to the Hall sensor. Hall amplifier 57 provides an output to control circuit 49 dependent upon the difference between its inputs. Hall amplifier 57 provides a pulse train on output 58 , registering either a positive or a negative pulse as each pole of the rotor passes. Consequently, the pulse train on output 58 is at the frequency of the commutation cycle. This information is used within commutation control circuit 49 to determine the position of the rotor 2 relative to the stator 1 , and consequently determine when each commutation cycle 12 should start and finish. [0096] For a controller 30 , in accordance with the present invention, the PWM functionality is further used to specifically control the voltage applied across the stator windings 3 and consequently the current flowing through the stator windings 3 towards the end of each drive portion of the commutation cycle, such that the current is gradually reduced, thereby avoiding the unwanted current spikes and large back EMFs at the end of each drive portion. In certain embodiments, the current is reduced to zero at the end of the drive portion, although it may alternatively be reduced substantially, but to a non-zero value (e.g. close to zero) thereby substantially reducing any voltage and/or current spikes which may then appear when the current is switched off completely. Alternatively, if the current is reduced to zero earlier then this gives a greater tolerance to timing inaccuracies at the point of commutation. [0097] To achieve this active current reduction, towards the end of each drive portion 13 of the commutation cycle 12 , the duty cycle of the pulse signal on lines 46 or 47 is reduced, such that the proportion of the time that the voltage is applied across the windings is reduced. This has the effect of gradually reducing the average voltage applied across the windings and therefore gradually reducing the current flowing through the stator windings 3 . [0098] Referring to FIG. 5 , this illustrates a partial circuit for achieving this gradual reduction in current within the stator windings 3 towards the end of each drive portion 13 of the commutation cycle 12 in accordance with an embodiment of the present invention. [0099] In order to be able to correctly time the reduction in current passing through the coil, it is necessary to generate a waveform indicative of the commutation cycle within the controller. Typically, the portion of the drive portion, during which the current supply to the stator windings is reduced, is a constant proportion of the drive portion regardless of the speed of rotation of the rotor. As the speed of rotation of the rotor changes the absolute time period during which the current supply to the stator windings is reduced will vary. However, it may be desirable to vary the proportion of the drive portion during which the current supply to the stator windings is reduced during fine tuning of the technique for some applications. [0100] The outputs of existing Hall effect sensor 56 , conventionally used to determine the commutation timings, are additionally used to generate waveforms indicative of both the speed of the motor and each commutation cycle. As before, the outputs of Hall effect sensor 56 are connected to inputs 54 and 55 of Hall amplifier 57 . Output 58 is a voltage pulse train signal, the frequency of which is equal to the frequency of the full single phase commutation cycle. [0101] As well as being supplied to commutation control circuit 49 as described above, Hall amplifier output 58 is also provided to an integrator circuit 60 and a saw tooth generator 61 . With reference to FIG. 6 , integrator 60 outputs a voltage waveform 70 , which is substantially a DC voltage, whose magnitude is proportional to the rotational speed of the rotor 2 . Saw tooth generator 61 outputs a substantially saw tooth waveform 71 at double the frequency of the pulse train signal output from the Hall amplifier 57 . Saw tooth waveform 71 starts at its lowest point at t 3 , i.e. at the end of a drive portion 13 of a commutation cycle. There is then a short flattened portion corresponding to the commutation delay 11 , before waveform 71 begins to rise at a substantially steady rate throughout the next drive portion (of the same, or a subsequent commutation cycle) to point t 3 . [0102] The outputs of integrator 60 and saw tooth generator 61 are passed to level detector 62 which gives an output 72 on control line 63 which at any moment is equal to the greater of waveforms 70 and 71 . Waveform 72 is equal to the saw tooth signal 71 where it crosses above DC level 70 , and DC level 70 at all other times. The portion of waveform 72 where it assumes the saw tooth waveform corresponds to that part of the drive portion of the commutation cycle during which it is desired to back off the pulse width modulation such that the average voltage applied across the stator windings is reduced, so as to actively reduce winding current. Waveform 72 is thus a current reduction control signal. [0103] The current reduction control waveform on line 63 may be combined with other signals controlling the output of the pulse width modulator 33 , for instance a speed control input 34 in combiner 64 . The effect of this additional control signal on line 63 is to progressively back off the PWM switching signal output on line 35 being provided to phase drive and control circuit 48 during an end portion of a drive portion of a commutation cycle. [0104] The PWM switching signal output 35 is backed off by reducing the duty cycle of the PWM signal. The effect of an increased speed control input is a reduced duty cycle over the whole of the commutation cycle. The effect of an increase in the current reduction control signal is to reduce the duty cycle of the PWM switching signal. This has the effect of reducing the average voltage applied across the stator windings and therefore reducing the current flowing through the stator windings. Alternatively, the pulse width modulator 33 may be arranged such that reducing either the speed control input 34 or the current reduction control signal 63 reduces the duty cycle of the PWM switching signal. [0105] Current reduction control signal 72 remains steady during the initial portion of each drive portion of the commutation cycle before beginning to ramp up linearly towards the end of the drive portion. Consequently, for an end portion of each drive portion of the commutation cycle it begins to reduce the average current flowing through the stator windings. The average current may be reduced to zero by or before the end of the drive portion (i.e. the time when all of the H-bridge switching devices are opened to remove current drive from the winding). There may be a gap between the initial portion and the end portion of each duty cycle. In particular, the initial portion may be considered to be only the initial portion of the drive portion during which the current flowing through the stator winding is rising to its initial peak. Similarly, the end portion of the duty cycle may be considered to be only the end portion of the duty cycle during which the magnitude of the stator winding current is being actively reduced. [0106] The duty cycle of the PWM output 35 is reduced during the period for which signal 72 rises above the DC level 70 , the reduction being in proportion to the magnitude of signal 72 . FIG. 7 illustrates schematically the PWM signal 80 provided to the phase drive and control circuit 48 on line 35 . For the first part 81 of the drive portion 13 of commutation cycle 12 the voltage signal being supplied to the H-bridge 37 is shown as being constantly on. This represents a motor running at full speed, with PWM duty cycle at 100%. However, it will be appreciated that if the motor is required to run at a lower speed then during period 81 signal 80 may be modulated to reduce the average current (i.e. the duty cycle may be less than 100%). In the second part 82 of the drive portion 13 of the commutation cycle 12 , the PWM duty cycle is progressively reduced. As before, there is a commutation delay 11 before the next drive portion, with the current being reversed through the stator windings. [0107] FIG. 8 illustrates the current 90 flowing through the stator windings of a DC brushless motor during each drive portion of each commutation cycle when controlled using the combined circuits of FIGS. 4 and 5 . As before, there is a peak 91 during the early part of the drive portion of the commutation cycle. As with the unmodified waveform, the current begins to fall back at point 92 as the poles of the stator and the rotor move further apart. This represents an intermediate, or middle, part of the drive portion in which winding current is being passively reduced, in the sense that drive is constant, and current magnitude is reducing only as a result of inductance changes. The passive change in current magnitude is not a result of any controlling action or step (i.e. change in any control parameter). Then, however, rather than current increasing towards the end of the drive portion, the current falls back progressively towards zero as indicated over the portion 93 of the waveform. This portion 93 is the end portion in which current magnitudes is actively reduced (i.e. by changing a control parameter). [0108] As the duty cycle of PWM modulated switching signal reduces individual peaks and troughs 94 in current 90 become evident, which are not readily detectable when the duty cycle is higher. However, it is the average current flowing at any one time that is important, and it may be readily seen that this progressively reduces before the end of the drive portion, at t 3 . The magnitude of the individual peaks and troughs 94 are increased due to the fact that the current 90 is measured at the ground return of the H-bridge. This effect is dependent upon the size of capacitor connected across the H-bridge. The current variations 94 within the stator windings are smaller due to recirculating currents. [0109] FIG. 9 illustrates the voltage on a supply 100 to a brushless DC motor according to an embodiment of the present invention. It is clear that the pulses 101 on the supply line corresponding to commutation points at the ends of the drive portions are much reduced compared with the unmodified motor, the voltage supply for which is shown in FIG. 3 . If the stator winding current is reduced completely to zero before the end of each drive portion of the duty cycle then the voltage spikes will be removed entirely. [0110] As the current during part 93 of the commutation cycle is actively backed off, there is a reduction in the average current drawn by the motor. A reduction in average current drawn by the motor of around 10% or better over the full commutation cycle has been achieved by implementing a method embodying the current invention. However, as the later part of the drive portion of the commutation cycle is inefficient in terms of transferring energy to the rotating rotor 2 , the reduction in average speed over the whole commutation cycle is significantly less, or even approximately zero. Consequently, a motor controlled by a controller in accordance with the present invention is significantly more efficient than an unmodified brushless DC motor. [0111] Referring now to FIG. 10 , this illustrates another control circuit (or control system) which may be used in embodiments of the invention to achieve active reduction in stator winding current towards the end of each drive portion 13 of a commutation cycle 12 . As in the circuit of FIG. 5 , this arrangement uses a Hall sensor 56 whose outputs 55 , 54 are supplied to a Hall amplifier 57 . The output 58 from the Hall amplifier 57 is substantially a square wave. However, rather than this square wave output 58 being supplied to an integrator and a saw-tooth generator as in FIG. 5 , in the example shown in FIG. 10 square wave output 58 is supplied just to a saw-tooth generator 61 and a commutation control circuit (not illustrated in the figure). The saw-tooth generator 61 generates a saw-tooth output signal 71 from the square wave input. The substantially saw-tooth wave form 71 output from the generator 61 is supplied to one input (in this example the non-inverting input) of a differential amplifier 200 , and to a peak detector 210 . The peak detector output 211 is a DC signal whose magnitude corresponds to the peak height of the saw-tooth signal and hence is proportional to the rotational speed (i.e. angular velocity) of the rotor. The peak detector output 211 is divided down using a potential divider 220 , and the divided down signal 221 is supplied to the other input (in this example the inverting input) of the amplifier 200 . The output 72 (on line 63 ) of the amplifier 200 has the approximate form shown in the figure. This wave form comprises substantially flat portions, corresponding to the times when the saw-tooth generator output voltage is less than the divided down signal 221 from the peak detector output 211 , and a series of peaks above that base level, corresponding to those times when the saw-tooth generator output voltage 71 exceeds the divided down voltage 221 derived from the peak detector output 211 . The peak detector output voltage 211 shifts up and down according to rotor speed and in proportion to the peak voltage of the saw-tooth signal 72 . Thus it will be appreciated that the output waveform 72 has substantially the same proportion of flat portion to peak saw-tooth portion regardless of the speed of rotation of the motor. This gives the control circuit in FIG. 10 some superiority over that shown in FIG. 5 where the saw-tooth signal 71 and integrator signal 70 are generated and may vary independently. The current reduction control signal 72 in the circuit of FIG. 10 may then be combined with a motor speed control signal 34 (which may also be referred to as a speed demand signal) and used to control a PWM generator 33 . The basic duty cycle of the PWM signal output from the generator 33 is determined by the speed control signal 34 . However, the effect of combining the speed control signal 34 with the current reduction control signal 72 is that the duty cycle of the PWM output 35 is progressively reduced during the end portion of each drive portion, i.e. at times corresponding to the positions of the peaks on the current reduction control signal 72 . [0112] Conveniently, in certain embodiments of the invention the Hall amplifier 57 , the saw-tooth generator 61 , the peak detector 210 , and the differential amplifier 200 are integrated on a single control chip. [0113] It will be appreciated that the circuit of FIG. 10 , by employing a peak detector 210 rather than an integrator 60 (as was the case in the circuit of FIG. 5 ), provides the advantage that the substantially DC voltage waveform 221 tracks in proportion to the peak of the saw-tooth waveform 71 . [0114] By reducing the magnitude of current and voltage spikes generated at the end of the drive portion(s) of the commutation cycle, and in some cases by avoiding these spikes altogether, embodiments of the invention provide the advantage that it is no longer necessary to use over specified components, resulting in motors that are cheaper to make and more efficient due to the reduced internal losses within, for instance, the transistors forming the H-bridge. [0115] As the current and voltage spikes are substantially reduced, and may be absent completely, a motor controlled (commutated) in accordance with the present invention is quieter than a motor controlled according to the prior art as audible clicks caused by rapid changes in energy within the stator 1 and the rotor 2 are reduced. [0116] As an alternative to controlling the current in the later part of the drive portion of the commutation cycle by utilising the PWM control circuit, the current may be progressively reduced by placing a linear component having a variable resistance in series with the stator windings 3 in accordance with a further embodiment of the present invention. This may be a variable resistor or transistor, or any other suitable component or circuit as is known in the art. Means are provided to detect the speed and the position of the motor, and typically this will comprise a similar arrangement of Hall effect sensor, Hall amplifier, integrator and saw tooth generator as discussed above. However, in place of passing the resultant control signal to PWM circuitry, the control signal will be provided to circuitry controlling the resistance of the component in series with the stator windings. [0117] Any other means of progressively reducing a current known in the art may be substituted for either of the above-described techniques. The controller may be formed from a single integrated circuit, with inputs and outputs to control the operation of the H-bridge, or the controller and the H-bridge may be combined into a single integrated circuit. Alternatively, the controller may be formed from discrete components and control circuits. [0118] The apparatus and methods embodying the invention and described in detail above are particularly applicable to the control of single phase brushless DC motors. However, the present invention may be applied to any form of brushless DC motor. It is particularly applicable to single and two phase motors, as it is for these types of motors that the problems of excessive current and voltage spikes are particularly significant, but may also be applied to the control of motors having more than two phase windings. [0119] Although the present invention has been primarily described above in connection with brushless DC motors, it will be readily apparent to the appropriately skilled person that the invention may also be applicable for control of an actuator comprising a stator, having at least one stator winding, and an armature (e.g. a plunger) arranged to move (e.g. linearly) with respect to the winding. The armature may, for example, comprise an elongate permanent magnet disposed within the winding, such that it may move linearly along the axis of the winding. By driving current through the winding in accordance with the above teaching controlled motion of the armature may be achieved. In particular, by applying a voltage having a drive portion during an end portion of which the voltage is progressively reduced, across the winding stepped motion of the plunger may be achieved. This is in contrast to normal actuators of this sort for which the current through the winding is either fully on or fully off, thereby only allowing the plunger to be moved from one extreme of its range of motion to the other, dependent upon the sense in which the voltage is applied across the winding. [0120] It will be readily apparent to the appropriately skilled person that although the present invention has been described in terms of controlling the flow of current through the stator windings of a brushless DC motor, the same techniques may be used to control the flow of current through other inductive loads. In particular, the present invention has particular utility in applications where the problems of current and voltage spikes when the current is switched off are significant. [0121] It will also be appreciated that the terms “winding” and “windings”, although encompassing structures formed from wire, are not limited to such structures. The stator winding(s) may comprise other forms of conductor arranged to provide suitable current paths. As just one example of alternative arrangements, a winding may be provided by a conductive track on a printed circuit. [0122] Other modifications, and applications, of the present invention will be readily apparent to the appropriately skilled person, without departing from the scope of the appended claims.

A method of controlling a brushless DC motor of the type having a stator, comprising a stator winding excitable to generate a stator magnetic field, and a rotor, arranged to rotate with respect to the stator and comprising permanently magnetised material arranged to generate a rotor magnetic field to interact with the stator magnetic field to produce rotation of the rotor. The method comprises the steps of driving current through the stator winding to generate a stator magnetic field to interact with the rotor magnetic field, detecting rotor position with respect to the stator, and cyclically commutating the stator winding current according to rotor position as the rotor rotates. Each commutation cycle includes a drive portion during which current is driven through the stator winding in one sense and at the end of which the driving of current in said sense is ceased. The method further comprises the steps of during an initial portion of each drive portion, driving current through the winding such that the magnitude of the winding current increases and during an end portion of each drive portion, actively reducing the magnitude of the winding current.

BACKGROUND The present disclosure relates generally to conserving power in link aggregation groups. As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option is an information handling system (IHS). An IHS generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes. Because technology and information handling needs and requirements may vary between different applications, IHSs may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in IHSs allow for IHSs to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, IHSs may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. Additionally, some embodiments of information handling systems include non-transient, tangible machine-readable media that include executable code that when run by one or more processors, may cause the one or more processors to perform the steps of methods described herein. Some common forms of machine readable media include, for example, floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, and/or any other medium from which a processor or computer is adapted to read. Computer networks form the interconnection fabric that enables reliable and rapid communications between computer systems and data processors that are both in close proximity to each other and at distant locations. These networks create a vast spider web of intranets and internets for handling all types of communication and information. Making all of this possible is a vast array of network switching products that make routing decisions in order to deliver packets of information from a source system or first network node to a destination system or second network node. Due to the size, complexity, and dynamic nature of these networks, sophisticated network switching products are often required to implement the interconnection fabric. This can be further complicated through other networking trends such as network virtualization. Many networks utilize parallelization and other techniques to improve the routing function between two network nodes. By employing parallelization, redundancy is built into a network so that it is possible that more than one path exists between any two nodes. This provides suitably aware network switching products with the ability to select between the redundant paths to avoid network congestion, balance network loads, and/or to avoid failures in the network. Parallelization also provides the ability to handle more network traffic between two nodes than is possible when parallelization is not utilized. In some implementations the parallelization is treated in a more formalized fashion in the form of link aggregation groups (LAGs), in which multiple network links are often bundled into a group to support the parallelization function. For suitably aware network switching products, the LAG can offer a flexible option to select any of the network links in the LAG for routing network traffic towards the next node in the path towards the traffic's final destination. And while LAGs offer additional flexibility in network topologies, they may also add complexity to the routing function and management of the network switching products to which they are attached. And as each network link added to a LAG may increase the quantity of network traffic that can be handled by the LAG, it may also add to the power consumption of both network switching products associated with the network link. Accordingly, it would be desirable to provide improved network switching products that can dynamically activate and deactivate network links within a LAG to reduce the power consumption of the associated network switching products. SUMMARY According to one embodiment, a method of reducing power consumption in a network switching unit includes detecting whether conditions are suitable for reducing power consumption in a first network switching unit. The first network switching unit includes a link aggregation group (LAG) and a plurality of communication ports, each communication port configured to couple the first network switching unit to a second network switching unit using a corresponding network link selected from a plurality of network links, and wherein the plurality of network links are assigned to the LAG. The method further includes requesting network link deactivation by sending a link deactivation request to the second network switching unit, determining whether the link deactivation request is approved, determining a first network link selected from the plurality of network links to deactivate, deactivating the first network link from use by the LAG, and reducing power supplied to the first network link. According to another embodiment, a method of reducing power consumption in a network switching unit includes receiving a link deactivation request by a first network switching unit from a second network switching unit. The first network switching unit includes a link aggregation group (LAG) and a plurality of communication ports, each communication port configured to couple the first network switching unit to the second network switching unit using a corresponding network link selected from a plurality of network links, and wherein the plurality of network links are assigned to the LAG. The method further includes determining whether the link deactivation request is acceptable, in response to determining that the link deactivation request is not acceptable, denying the link deactivation request, in response to determining that the link deactivation request is acceptable, confirming the link deactivation request, determining a first network link selected from the plurality of network links to deactivate, deactivating the first network link from use by the LAG, and reducing power supplied to the first network link. According to yet another embodiment, an information handling system includes a first network switching unit. The first network switching unit includes a link aggregation group (LAG) and a plurality of communication ports, each communication port configured to couple the first network switching unit to a second network switching unit using a corresponding network link selected from a plurality of network links, and wherein the plurality of network links are assigned to the LAG. The first network switching unit is configured to detect whether conditions are suitable for reducing power consumption, request network link deactivation by sending a link deactivation request to the second network switching unit, determine whether the link deactivation request is approved, determine a first network link selected from the plurality of network links to deactivate, deactivate the first network link from use by the LAG, and reduce power supplied to the first network link. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a shows a simplified diagram of a network according to some embodiments. FIG. 1 b shows a simplified diagram of the network with a network link deactivated according to some embodiments. FIG. 2 shows a simplified diagram of a method of reducing power consumption in a network switching unit according to some embodiments. FIG. 3 is a simplified diagram of a method of reducing power consumption in a network switching unit according to some embodiments. FIG. 4 is a simplified diagram of a method of activating a network link in a network switching unit according to some embodiments. FIG. 5 is a simplified diagram of a method of activating a network link in a network switching unit according to some embodiments. FIG. 6 is a simplified diagram of an extension to an actor and a partner state of a LACP data unit (LACPDU) according to some embodiments. In the figures, elements having the same designations have the same or similar functions. DETAILED DESCRIPTION In the following description, specific details are set forth describing some embodiments consistent with the present disclosure. It will be apparent, however, to one skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure. In addition, to avoid unnecessary repetition, one or more features shown and described in association with one embodiment may be incorporated into other embodiments unless specifically described otherwise or if the one or more features would make an embodiment non-functional. For purposes of this disclosure, an IHS may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, entertainment, or other purposes. For example, an IHS may be a personal computer, a PDA, a consumer electronic device, a display device or monitor, a network server or storage device, a switch router or other network communication device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The IHS may include memory, one or more processing resources such as a central processing unit (CPU) or hardware or software control logic. Additional components of the IHS may include one or more storage devices, one or more communications ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The IHS may also include one or more buses operable to transmit communications between the various hardware components. FIG. 1 a shows a simplified diagram of a network 100 according to some embodiments. As shown in FIG. 1 a , the network 100 may include a network switching unit 110 and a network switching unit 120 . The network switching unit 110 may include one or more communication ports 131 - 133 . Each of the one or more communication ports 131 - 133 may be coupled to a corresponding one of one or more network links 141 - 143 . Communication port 131 may be coupled to network link 141 , communication port 132 may be coupled to network link 142 , and communication port 133 may be coupled to network link 143 . The network switching unit 120 may include one or more communication ports 151 - 153 . Each of the one or more communication ports 151 - 153 may be coupled to a corresponding one of the one or more network links 141 - 143 . Communication port 151 may be coupled to network link 141 , communication port 152 may be coupled to network link 142 , and communication port 153 may be coupled to network link 143 . Network switching unit 110 may route network traffic to network switching unit 120 by sending it to any one of the communication ports 131 - 133 where it is sent on the corresponding one of the network links 141 - 143 toward network switching unit 120 . Similarly, network switching unit 120 may route network traffic to network switching unit 110 by sending it to any one of the communication ports 151 - 153 where it is sent on the corresponding one of the network links 141 - 143 toward network switching unit 110 . Thus, the network links 141 - 143 can provide parallel and alternative network paths between the network switching unit 110 and the network switching unit 120 . The parallel nature of the network links 141 - 143 may be formalized in each of the network switching units 110 and 120 through the use of link aggregation groups. Network switching unit 110 may group the network links 141 - 143 into a LAG 161 . When network switching unit 110 desires to route network traffic to network switching unit 120 it may route the network traffic using LAG 161 , leaving the decision of which of the network links 141 - 143 and corresponding communication ports 131 - 133 to use to a LAG hashing algorithm. Similarly, network switching unit 120 may group the network links 141 - 143 into a LAG 162 . When network switching unit 120 desires to route network traffic to network switching unit 110 it may route the network traffic using LAG 162 . Because network utilization may change based on the amount of network traffic being routed and/or the source(s) and destination(s) of the network traffic, the amount of network traffic that needs to be handled by network links 141 - 143 may increase or decrease. A network designer may generally choose the number of parallel network links 141 - 143 between the network switches 110 and 120 based on an expected maximum traffic load to reduce a potential for a loss of network traffic. However, there may be times when the actual traffic load being handled by network links 141 - 143 may be significantly less than the expected maximum traffic load or even non-existent. A ratio of the actual traffic load to a maximum traffic load that can be handled by a LAG is often referred to as the utilization for the LAG. A low utilization may indicate a low traffic load and a high utilization may indicate a high traffic load. In some embodiments, where there is an extended period of time where the utilization is low, it may be advantageous to deactivate one or more of the network links in a LAG to reduce power consumption. In some embodiments, it may be advantageous to reduce power consumption in the LAG for other reasons. In some embodiments, power consumption may be reduced to lower a need for heat dissipation and to lower the temperature of the network switching units 110 and 120 . In some embodiments, power consumption may be reduced to lower a peak power demand. In some embodiments, power consumption may be reduced based on a time of day. FIG. 1 b shows a simplified diagram of the network 100 with the network link 143 deactivated according to some embodiments. As shown in FIG. 1 b , the network link 143 has been deactivated to reduce, for example, power consumption. Network traffic may now only move between the network switching units 110 and 120 using network links 141 and 142 . Network link 143 may also be deactivated for use in LAGs 161 and 162 so that the LAG hashing algorithms of network switching units 110 and 120 will not route network traffic using network link 143 . Because network link 143 is deactivated, network switching unit 110 may reduce or remove power from network link 143 . In some embodiments, network switching unit 110 may also reduce or remove power from communication port 133 . In some embodiments, network switching unit 110 may also reduce or remove power from other circuitry associated with communication port 133 and/or network link 143 . Network switching unit 120 may similarly reduce or remove power from network link 143 , communication port 153 , and/or other circuitry associated with communication port 153 and/or network link 143 . Thus, the overall power consumption of the network switching units 110 and 120 , as well as the network 100 may be reduced. As discussed above and further emphasized here, FIGS. 1 a and 1 b are merely examples, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. According to some embodiments, there may be fewer than three or more than three network links 141 - 143 coupling the network switching units 110 and 120 . FIG. 2 shows a simplified diagram of a method 200 of reducing power consumption in a network switching unit according to some embodiments. As shown in FIG. 2 , the method 200 includes a process 210 for detecting power conservation conditions, a process 220 for requesting network link deactivation, a process 230 for receiving a response to the request, a process 240 for determining whether the request was confirmed, a process 250 for negotiating a network link to deactivate, a process 260 for deactivating the network link from use by a LAG, and a process 270 for reducing the network link power. According to certain embodiments, the method 200 of reducing power consumption in a network switching unit can be performed using variations among the processes 210 - 270 as would be recognized by one of ordinary skill in the art. According to some embodiments, the process 230 is optional and may be omitted. In some embodiments, one or more of the processes 210 - 270 may be implemented, at least in part, in the form of executable code stored on non-transient, tangible, machine readable media that when run by one or more processors in one or more network switching units (e.g., the network switching units 110 and/or 120 ) may cause the one or more processors to perform one or more of the processes 210 - 270 . At the process 210 , a network switching unit (e.g., the network switching unit 110 and/or 120 ) may detect whether network conditions are suitable for reducing power consumption on one of the network switching unit's LAGs (e.g., the LAG 161 and/or 162 ). According to some embodiments, power consumption may be reduced when a utilization of the LAG falls below a minimum utilization threshold for a period of time. In some embodiments, the minimum utilization threshold may be 10% or lower. In some embodiments, the minimum utilization threshold may be 20% or lower. In some embodiments, the minimum utilization threshold may be set as part of the configuration of the network switching unit. In some embodiments, the minimum utilization threshold may be set using a configuration utility. In some embodiments, the minimum utilization threshold may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the minimum utilization threshold may be dynamic based on a time of day and/or other network settings and/or conditions. In some embodiments, the period of time may be as short as a second or less. In some embodiments, the period of time may be as short as a minute or less. In some embodiments, the period of time may be 5-10 minutes or more in length. In some embodiments, the period of time may be set as part of the configuration of the network switching unit. In some embodiments, the period of time may be set using a configuration utility. In some embodiments, the period of time may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the period of time may be dynamic based on a time of day and/or other network settings and/or conditions. According to some embodiments, power consumption may be reduced when a temperature of the network switching unit exceeds a maximum temperature threshold. In some embodiments, the maximum temperature threshold may be 70 degrees centigrade or higher. In some embodiments, the maximum temperature threshold may be 85 degrees centigrade or higher. In some embodiments, the maximum temperature threshold may be 125 degrees centigrade or higher. In some embodiments, the maximum temperature threshold may be set as part of the configuration of the network switching unit. In some embodiments, the maximum temperature threshold may be set using a configuration utility. In some embodiments, the maximum temperature threshold may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the maximum temperature threshold may be dynamic based on a time of day and/or other network settings and/or conditions. According to some embodiments, power consumption may be reduced based on a time of day. According to some embodiments, power consumption may be reduced based on one or more of the factors described above. In some embodiments, any logical and/or temporal combination of the one or more factors may be considered. At the process 220 , the network switching unit makes a request for link deactivation. According to some embodiments, the network switching unit may select a LAG (e.g., the LAG of process 210 whose utilization is below the minimum utilization threshold). In some embodiments, the network switching unit may send a network link deactivation message to a neighboring network switching unit (e.g., the network switching unit 120 and/or 110 ) using one of the network links (e.g., the network links 140 - 143 ) in the LAG. In some embodiments, the link deactivation message may ask the neighboring network switching unit whether it is willing to deactivate one of their shared network links. At the optional process 230 , the network switching unit receives a response to the link deactivation request. According to some embodiments, the network switching unit may receive a response message on one of the network links in the LAG. In some embodiments, the response message may include information indicating whether the neighboring network switching unit is willing to deactivate one of their shared network links. At the process 240 , the network switching unit may determine whether the network link deactivation request is confirmed. According to some embodiments, the network switching unit examines the response message. According to some embodiments, the network deactivation request may not be confirmed when no response message is received. In some embodiments, the network deactivation request may not be confirmed when a response message is not received during a timeout period following the making of the deactivation request. In some embodiments, the timeout period is several milliseconds. In some embodiments, the timeout period is a second or longer. In some embodiments, the timeout period may be set as part of the configuration of the network switching unit. In some embodiments, the timeout period may be set using a configuration utility. In some embodiments, the timeout period may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the timeout period may be dynamic based on a time of day and/or other network settings and/or conditions. If the network switching unit determines that the network link deactivation request has not been confirmed, the method 200 returns to process 210 . At the process 250 , the network switching unit and the neighboring network switching unit may negotiate which network link should be deactivated. According to some embodiments, the network link is selected based on a mutually agreed upon criteria. In some embodiments, the network link, from among the active network links, with a largest ID number is selected. In some embodiments, the network link, from among the active network links, with a smallest ID number is selected. According to some embodiments, the network switching unit and the neighboring switching unit may exchange one or more negotiation messages to determine the network link to deactivate. At the process 260 , the network switching unit may deactivate the network link from use by the LAG. According to some embodiments, the network link may be removed from consideration by a LAG hashing algorithm used to select from among the network links associated with the LAG. At the process 270 , the network switching unit may reduce power provided to the network link. According to some embodiments, the network switching unit may reduce some power or remove all power to the network link. According to some embodiments, the network switching unit may reduce or remove power from a communication port (e.g., one of the communication ports 131 - 133 and/or 151 - 153 ) corresponding to the network link. According to some embodiments, the network switching unit may also reduce or remove power from other circuitry associated with the communication port and/or the network link. As discussed above and further emphasized here, FIG. 2 is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. According to some embodiments, upon completion of the process 270 , the method 200 may return to process 210 to determine whether one or more additional network links may be deactivated. FIG. 3 is a simplified diagram of a method 300 of reducing power consumption in a network switching unit according to some embodiments. As shown in FIG. 3 , the method 300 includes a process 310 for receiving a network link deactivation request, a process 320 for determining whether deactivation of a network link is acceptable, a process 330 for denying the request, a process 340 for confirming the request, a process 350 for negotiating a network link to deactivate, a process 360 for deactivating the network link from use by a LAG, and a process 370 for reducing the network link power. According to certain embodiments, the method 300 of reducing power consumption in a network switching unit can be performed using variations among the processes 310 - 370 as would be recognized by one of ordinary skill in the art. According to some embodiments, the process 330 is optional and may be omitted. In some embodiments, one or more of the processes 310 - 370 may be implemented, at least in part, in the form of executable code stored on non-transient, tangible, machine readable media that when run by one or more processors in one or more network switching units (e.g., the network switching units 110 and/or 120 ) may cause the one or more processors to perform one or more of the processes 310 - 370 . At the process 310 , a network switching unit (e.g., the network switching unit 110 and/or 120 ) may receive a network link deactivation request. In some embodiments, the network link deactivation request may be the network link deactivation request from process 220 . In some embodiments, the network link deactivation request may be in the form of a network link deactivation message sent by a neighboring network switching unit (e.g., the network switching unit 120 and/or 110 ) using one of the network links (e.g., the network links 140 - 143 ) in a LAG (e.g., the LAG 162 and/or 161 ). At the process 320 , the network switching unit determines whether deactivation of a network link is acceptable. According to some embodiments, the network switching unit may make its determination using one or more factors similar to the one or more factors used in the process 210 to detect whether network conditions are suitable for reducing power consumption. In some embodiments, the network switching unit may consider a utilization of the LAG. In some embodiments, the network switching unit may consider a temperature of the network switching unit. In some embodiments, the network switching unit may consider a time of day. In some embodiments, any logical and/or temporal combination of the one or more factors may be considered. According to some embodiments, the network switching unit may recognize that it has network traffic to route to the neighboring network switching unit that the neighboring network switching may not have been able to consider when it made the network link deactivation request. If the network switching unit determines that deactivation of a network link is not acceptable, the method 300 moves to process 330 . Otherwise, the method 300 moves to process 340 . At the optional process 330 , the network switching unit denies the deactivation request. According to some embodiments, the network switching unit may send a response message on one of the network links in the LAG. In some embodiments, the response message may include information indicating that the network switching unit is not willing to deactivate one of its network links. In some embodiments, the response message may be the response received by the neighboring network switching device in process 230 . At the process 340 , the network switching unit confirms the deactivation request. According to some embodiments, the network switching unit may send a response message on one of the network links in the LAG. In some embodiments, the response message may include information indicating that the network switching unit is willing to deactivate one of its network links. In some embodiments, the response message may be the response received by the neighboring network switching device in process 230 . At the process 350 , the network switching unit and the neighboring network switching unit may negotiate which network link should be deactivated. According to some embodiments, the network link is selected based on a mutually agreed upon criteria. In some embodiments, the network link, from among the active network links, with a largest ID number is selected. In some embodiments, the network link, from among the active network links, with a smallest ID number is selected. According to some embodiments, the network switching unit and the neighboring switching unit may exchange one or more negotiation messages to determine the network link to deactivate. According to some embodiments, the selected network link is the same network link selected in process 250 . At the process 360 , the network switching unit may deactivate the network link from use by the LAG. According to some embodiments, the network link may be removed from consideration by a LAG hashing algorithm used to select from among the network links associated with the LAG. At the process 370 , the network switching unit may reduce power provided to the network link. According to some embodiments, the network switching unit may reduce some power or remove all power to the network link. According to some embodiments, the network switching unit may reduce or remove power from a communication port (e.g., one of the communication ports 151 - 153 and/or 131 - 133 ) corresponding to the network link. According to some embodiments, the network switching unit may also reduce or remove power from other circuitry associated with the communication port and/or the network link. As discussed above and further emphasized here, FIG. 3 is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. According to some embodiments, upon completion of the process 370 , the method 300 may return to process 310 to wait for another network link deactivation request. According to some embodiments, upon completion of the process 370 , the method 300 may switch to process 210 of method 200 to detect whether network conditions are suitable for reducing power consumption on one of the network switching unit's LAGs. FIG. 4 is a simplified diagram of a method 400 of activating a network link in a network switching unit according to some embodiments. As shown in FIG. 4 , the method 400 includes a process 410 for detecting an end of power conservation conditions, a process 420 for requesting network link activation, a process 430 for receiving a response to the request, a process 440 for determining whether the request was confirmed, a process 450 for negotiating a network link to activate, a process 460 for returning the network link power, and a process 470 for activating the network link for use by a LAG. According to certain embodiments, the method 400 of activating a network link in a network switching unit can be performed using variations among the processes 410 - 470 as would be recognized by one of ordinary skill in the art. According to some embodiments, the process 430 is optional and may be omitted. In some embodiments, one or more of the processes 410 - 470 may be implemented, at least in part, in the form of executable code stored on non-transient, tangible, machine readable media that when run by one or more processors in one or more network switching units (e.g., the network switching units 110 and/or 120 ) may cause the one or more processors to perform one or more of the processes 410 - 470 . At the process 410 , a network switching unit (e.g., the network switching unit 110 and/or 120 ) may detect an end of power conservation conditions. According to some embodiments, the process 410 may only occur when one or more of the network links (e.g., the network links 141 - 143 ) of a LAG (e.g., the LAG 161 and/or 162 ) are deactivated. In some embodiments, the one or more network links may have been deactivated by the method 200 and/or the method 300 . According to some embodiments, the end of power conservation conditions may indicate that network conditions suggest that additional network links should be activated in the LAG. According to some embodiments, the end of power conservation conditions may occur when a utilization of the LAG rises above a maximum utilization threshold for a period of time. In some embodiments, the maximum utilization threshold may be 80% or higher. In some embodiments, the maximum utilization threshold may be 60% or higher. In some embodiments, the maximum utilization threshold may be set as part of the configuration of the network switching unit. In some embodiments, the maximum utilization threshold may be set using a configuration utility. In some embodiments, the maximum utilization threshold may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the maximum utilization threshold may be dynamic based on a time of day and/or other network settings and/or conditions. In some embodiments, the period of time may be as short as a second or less. In some embodiments, the period of time may be as short as a minute or less. In some embodiments, the period of time may be 5-10 minutes or more in length. In some embodiments, the period of time may be set as part of the configuration of the network switching unit. In some embodiments, the period of time may be set using a configuration utility. In some embodiments, the period of time may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the period of time may be dynamic based on a time of day and/or other network settings and/or conditions. According to some embodiments, the end of power conservation conditions may occur when a temperature of the network switching unit drops below a minimum temperature threshold. In some embodiments, the minimum temperature threshold may be 100 degrees centigrade or lower. In some embodiments, the minimum temperature threshold may be 65 degrees centigrade or lower. In some embodiments, the minimum temperature threshold may be 40 degrees centigrade or higher. In some embodiments, the minimum temperature threshold may be set as part of the configuration of the network switching unit. In some embodiments, the minimum temperature threshold may be set using a configuration utility. In some embodiments, the minimum temperature threshold may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the minimum temperature threshold may be dynamic based on a time of day and/or other network settings and/or conditions. According to some embodiments, the end of power conservation conditions may occur based on a time of day. According to some embodiments, the end of power conservation conditions may occur based on one or more of the factors described above. In some embodiments, any logical and/or temporal combination of the one or more factors may be considered. At the process 420 , the network switching unit makes a request for link activation. According to some embodiments, the network switching unit may select a LAG (e.g., the LAG of process 410 whose utilization is above the maximum utilization threshold). In some embodiments, the network switching unit may send a network link activation message to a neighboring network switching unit (e.g., the network switching unit 120 and/or 110 ) using one of the network links (e.g., the network links 140 - 143 ) in the LAG. In some embodiments, the link activation message may ask the neighboring network switching unit whether it is willing to activate one of their shared network links. At the optional process 430 , the network switching unit receives a response to the link activation request. According to some embodiments, the network switching unit may receive a response message on one of the network links in the LAG. In some embodiments, the response message may include information indicating whether the neighboring network switching unit is willing to activate one of their shared network links. At the process 440 , the network switching unit may determine whether the network link activation request is confirmed. According to some embodiments, the network switching unit examines the response message. According to some embodiments, the network activation request may not be confirmed when no response message is received. In some embodiments, the network deactivation request may not be confirmed when a response message is not received during a timeout period following the making of the activation request. In some embodiments, the timeout period is several milliseconds. In some embodiments, the timeout period is a second or longer. In some embodiments, the timeout period may be set as part of the configuration of the network switching unit. In some embodiments, the timeout period may be set using a configuration utility. In some embodiments, the timeout period may be stored in one or more memory devices (e.g., ROM, RAM, PROM, EPROM, FLASH-EPROM, and/or any other memory chip or cartridge) coupled to the network switching unit. In some embodiments, the timeout period may be dynamic based on a time of day and/or other network settings and/or conditions. If the network switching unit determines that the network link activation request has not been confirmed, the method 400 returns to process 410 . At the process 450 , the network switching unit and the neighboring network switching unit may negotiate which network link should be activated. According to some embodiments, the network link is selected based on a mutually agreed upon criteria. In some embodiments, the network link, from among the deactivated network links, with a largest ID number is selected. In some embodiments, the network link, from among the deactivated network links, with a smallest ID number is selected. According to some embodiments, the network switching unit and the neighboring switching unit may exchange one or more negotiation messages to determine the network link to activate. According to some embodiments, when only one network link in the LAG is deactivated, it may be selected by default. At the process 460 , the network switching unit may return power to the network link. According to some embodiments, the network switching unit may return power to a communication port (e.g., one of the communication ports 131 - 133 and/or 151 - 153 ) corresponding to the network link. According to some embodiments, the network switching unit may also return power to other circuitry associated with the communication port and/or the network link. At the process 470 , the network switching unit may activate the network link for use by the LAG. According to some embodiments, the network link may be added to consideration by a LAG hashing algorithm used to select from among the network links associated with the LAG. As discussed above and further emphasized here, FIG. 4 is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. According to some embodiments, upon completion of the process 470 , the method 400 may return to process 410 to determine whether one or more additional network links may be activated. According to some embodiments, upon completion of the process 470 , the method may switch to method 200 and/or 300 when a reduction in power consumption is desired. FIG. 5 is a simplified diagram of a method 500 of activating a network link in a network switching unit according to some embodiments. As shown in FIG. 5 , the method 500 includes a process 510 for receiving a network link activation request, a process 520 for determining whether activation of a network link is acceptable, a process 530 for denying the request, a process 540 for confirming the request, a process 550 for negotiating a network link to activate, a process 560 for returning the network link power, and a process 570 for activating the network link for use by a LAG. According to certain embodiments, the method 500 of reducing power consumption in a network switching unit can be performed using variations among the processes 510 - 570 as would be recognized by one of ordinary skill in the art. According to some embodiments, the process 530 is optional and may be omitted. In some embodiments, one or more of the processes 510 - 570 may be implemented, at least in part, in the form of executable code stored on non-transient, tangible, machine readable media that when run by one or more processors in one or more network switching units (e.g., the network switching units 110 and/or 120 ) may cause the one or more processors to perform one or more of the processes 510 - 570 . At the process 510 , a network switching unit (e.g., the network switching unit 110 and/or 120 ) may receive a network link activation request. In some embodiments, the network link activation request may be the network link activation request from process 420 . In some embodiments, the network link activation request may be in the form of a from a network link activation message sent by a neighboring network switching unit (e.g., the network switching unit 120 and/or 110 ) using one of the network links (e.g., the network links 140 - 143 ) in a LAG (e.g., the LAG 162 and/or 161 ). At the process 520 , the network switching unit determines whether activation of a network link is acceptable. According to some embodiments, the network switching unit may make its determination using one or more factors similar to the one or more factors used in the process 410 to detect whether network conditions are suitable for activating a network link. In some embodiments, the network switching unit may consider a utilization of the LAG. In some embodiments, the network switching unit may consider a temperature of the network switching unit. In some embodiments, the network switching unit may consider a time of day. In some embodiments, any logical and/or temporal combination of the one or more factors may be considered. According to some embodiments, the network switching unit may have an elevated temperature that does not permit activation of a network link. If the network switching unit determines that activation of a network link is not acceptable, the method 500 moves to process 530 . Otherwise, the method 500 moves to process 540 . At the optional process 530 , the network switching unit denies the activation request. According to some embodiments, the network switching unit may send a response message on one of the network links in the LAG. In some embodiments, the response message may include information indicating that the network switching unit is not willing to activate one of its network links. In some embodiments, the response message may be the response received by the neighboring network switching device in process 430 . At the process 540 , the network switching unit confirms the activation request. According to some embodiments, the network switching unit may send a response message on one of the network links in the LAG. In some embodiments, the response message may include information indicating that the network switching unit is willing to activate one of its network links. In some embodiments, the response message may be the response received by the neighboring network switching device in process 430 . At the process 550 , the network switching unit and the neighboring network switching unit may negotiate which network link should be activated. According to some embodiments, the network link is selected based on a mutually agreed upon criteria. In some embodiments, the network link, from among the deactivated network links, with a largest ID number is selected. In some embodiments, the network link, from among the deactivated network links, with a smallest ID number is selected. According to some embodiments, the network switching unit and the neighboring switching unit may exchange one or more negotiation messages to determine the network link to activate. According to some embodiments, when only one network link in the LAG is deactivated, it may be selected by default. According to some embodiments, the selected network link is the same network link selected in process 450 . At the process 560 , the network switching unit may return power to the network link. According to some embodiments, the network switching unit may return power to a communication port (e.g., one of the communication ports 151 - 153 and/or 131 - 133 ) corresponding to the network link. According to some embodiments, the network switching unit may also return power to other circuitry associated with the communication port and/or the network link. At the process 570 , the network switching unit may activate the network link for use by the LAG. According to some embodiments, the network link may be added to consideration by a LAG hashing algorithm used to select from among the network links associated with the LAG. As discussed above and further emphasized here, FIG. 5 is merely an example, which should not unduly limit the scope of the claims. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. According to some embodiments, upon completion of the process 570 , the method 500 may return to process 510 to wait for another network link activation request. According to some embodiments, upon completion of the process 570 , the method 500 may switch to process 410 of method 400 to detect whether network conditions are suitable for activating another network link. According to some embodiments, upon completion of the process 570 , the method may switch to method 200 and/or 300 when a reduction in power consumption is desired. According to certain embodiments the methods 200 , 300 , 400 , and/or 500 may be implemented using an extension to the Link Aggregation Control Protocol (LACP) as described in the IEEE 802.1AX standard. FIG. 6 is a simplified diagram of an extension 600 to an actor and a partner state of a LACP data unit (LACPDU) according to some embodiments. As shown in FIG. 6 , the extension 600 to the actor and/or partner state includes a conserve power bit 610 with the remaining bits 620 being reserved for other uses. The conserve power bit 610 may be used to designate whether a network switching unit (e.g., the actor or the partner) is willing to activate and/or deactivate a network link. According to some embodiments, a conserve power value of the conserve power bit 610 may indicate a willingness to deactivate a network link and a normal power value of the conserve power bit 610 may indicate an unwillingness to deactivate a network link. In some embodiments, the conserve power value may be a logic 1 and the normal power value may be a logic 0. According to some embodiments, the extension 600 to the actor and partner state may be used in the method 200 . At the process 220 , the network switching unit (i.e., the actor) may format and send a LACPDU with the actor state extension 600 containing the conserve power value for the conserve power bit 610 . By sending the LACPDU with the conserve power bit 610 set to the conserve power value, the network switching unit indicates that it desires a reduction in power. At the process 230 , the network switching unit may receive a LACPDU from the neighboring network switching unit (i.e., the partner) with the partner state extension 600 . When the partner state extension 600 includes the conserve power value for the conserve power bit 610 , the network switching unit may determine that the deactivation request is confirmed during process 240 . When the partner state extension 600 includes the normal power value for the conserve power bit 610 , the network switching unit may determine that the deactivation request is not confirmed during process 240 . At the process 260 , the network switching unit may deactivate the network link from use by the LAG by changing a state of the selected network link and/or the corresponding communication port from NORMAL to STANDBY. According to some embodiments, the extension 600 to the actor and partner state may be used in the method 300 . At the process 310 , the network switching unit (i.e., the partner) may receive a LACPDU from the neighboring network switching unit (i.e., the actor) with the actor state extension 600 containing the conserve power value for the conserve power bit 610 , thus making a link deactivation request. The network switching unit may respond to the link deactivation request by responding with a LACPDU containing a partner state extension 600 . By sending the conserve power value as the conserve power bit 610 , the network switching unit may confirm the link deactivation request in process 340 . By sending the normal power value as the conserve power bit 610 , the network switching unit may deny the link deactivation request in process 330 . At the process 360 , the network switching unit may deactivate the network link from use by the LAG by changing the state of the selected network link and/or the corresponding communication port from NORMAL to STANDBY. According to some embodiments, the extension 600 to the actor and partner state may be used in the method 400 . At the process 420 , the network switching unit (i.e., the actor) may format and send a LACPDU with the actor state extension 600 containing the normal power value for the conserve power bit 610 . By sending the LACPDU with the conserve power bit 610 set to the normal power value, the network switching unit indicates that it desires to activate a network link. At the process 430 , the network switching unit may receive a LACPDU from the neighboring network switching unit (i.e., the partner) with the partner state extension 600 . When the partner state extension 600 includes the conserve power value for the conserve power bit 610 , the network switching unit may determine that the activation request is not confirmed during process 440 . When the partner state extension 600 includes the normal power value for the conserve power bit 610 , the network switching unit may determine that the activation request is confirmed during process 440 . At the process 470 , the network switching unit may activate the network link from use by the LAG by changing a state of the selected network link and/or the corresponding communication port from STANDBY to NORMAL. According to some embodiments, the extension 600 to the actor and partner state may be used in the method 500 . At the process 510 , the network switching unit (i.e., the partner) may receive a LACPDU from the neighboring network switching unit (i.e., the actor) with the actor state extension 600 containing the normal power value for the conserve power bit 610 , thus making a link activation request. The network switching unit may respond to the link activation request by responding with a LACPDU containing a partner state extension 600 . By sending the conserve power value as the conserve power bit 610 , the network switching unit may deny the link activation request in process 530 . By sending the normal power value as the conserve power bit 610 , the network switching unit may confirm the link activation request in process 540 . At the process 570 , the network switching unit may activate the network link from use by the LAG by changing a state of the selected network link and/or the corresponding communication port from STANDBY to NORMAL. Some embodiments of network switching units 110 and/or 120 may include non-transient, tangible, machine readable media that include executable code that when run by one or more processors may cause the one or more processors to perform the processes of methods 200 , 300 , 400 , and/or 500 as described above. Some common forms of machine readable media that may include the processes of methods 200 , 300 , 400 , and/or 500 are, for example, floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, and/or any other medium from which a processor or computer is adapted to read. Although illustrative embodiments have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure and in some instances, some features of the embodiments may be employed without a corresponding use of other features. One of ordinary skill in the art would recognize many variations, alternatives, and modifications. Thus, the scope of the invention should be limited only by the following claims, and it is appropriate that the claims be construed broadly and in a manner consistent with the scope of the embodiments disclosed herein.

A system and method of reducing power consumption in a network switching unit includes detecting whether conditions are suitable for reducing power consumption in a first network switching unit. The first network switching unit includes a link aggregation group (LAG) and a plurality of communication ports, each communication port configured to couple the first network switching unit to a second network switching unit using a corresponding network link selected from a plurality of network links, and wherein the plurality of network links are assigned to the LAG. The system and method further includes requesting network link deactivation by sending a link deactivation request to the second network switching unit, determining whether the link deactivation request is approved, determining a first network link selected from the plurality of network links to deactivate, deactivating the first network link from use by the LAG, and reducing power supplied to the first network link.

FIELD OF THE INVENTION The present invention relates to new D 3 dopamine receptor subtype selective ligands of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or salts and/or hydrates and/or solvates thereof which are useful in the therapy and/or prevention of psychoses (e.g. schizophrenia, schizo-affective disorders, etc.) and other central nervous system and ophthalmological disorders. The present invention also relates to the processes for producing compounds of formula (I) and to pharmacological compositions containing the same. DESCRIPTION OF THE PRIOR ART PCT Patent Publication WO 98/50364 describes tetrahydroisoquinoline derivatives which have affinity for dopamine receptors and useful as antipsychotic agents. PCT Patent Publication WO 97/45403 discloses aryl substituted cyclic amines as selective dopamine D 3 ligands. German Patent Publication DE 19728996 describes triazol derivatives. The compounds are said to be dopamine D 3 receptor antagonists and/or agonists useful for the treatment of central nervous system disorders e.g. Parkinson's disease or schizophrenia. Although the compounds mentioned in the above publications have affinity for dopamine D 3 receptors, their chemical structures differ from the structure of compounds of the present invention. SUMMARY OF THE INVENTION We have found a class of sulfonamide derivatives which have high affinity for dopamine D 3 receptors and selectivity over other receptors, especially dopamine D 2 . The selectivity is particularly important as the undesired side effects of the compounds are much less pronounced. The present invention relates to new D 3 dopamine receptor subtype selective ligands having sulfonamide structures of formula (I) wherein X represents a nitrogen atom or CH group; Y represents a bond when X stands for nitrogen, or an oxygen atom or NH or CH 2 or OCH 2 group when X stands for CH group; R 1 , R 2 , R 3 may be the same or different and represent independently a substituent selected from hydrogen, halogen, C 1-6 -alkyl, C 1-6 alkoxy, cyano, hydroxy, trifluoromethyl, C 1-6 -alkylsulfonyloxy, trifluoromethanesulfonyloxy, C 1-6 -alkanoyloxy, amino, alkylamino, alkanoylamino, alkylsulfonylamino, arylsulfonylamino, aminocarbonyl, carboxy, N-hydroxycarmamimidoyl, carbamimidoyl, hydroxycarbamoyl, thiocarbamoyl, sulfamoyl, mono or bicyclic heterocyclic group or optionally substituted phenyl, or two adjacent groups of R 1 , R 2 and R 3 may combine to form an optionally substituted fused mono or bicyclic heterocyclic group; Q represents a dialkylamino group or an optionally substituted alkyl, aryl, heteroaryl, aralkyl or heteroaralkyl group and/or geometric isomers and/or stereoisomers and/or diastereomers and/or salts and/or hydrates and/or solvates thereof, to the processes for producing the same, to the pharmacological compositions containing the same and their use in therapy and/or prevention of psychoses (e.g. schizophrenia, schizo-affective disorders, etc.), drug (e.g. alcohol, cocaine and nicotine, opioids etc.) abuse, cognitive impairment accompanying schizophrenia, mild-to-moderate cognitive deficits, amnesia, eating disorders (e.g. bulimia nervosa, etc.), attention deficit disorders, hyperactivity disorders in children, psychotic depression, mania, paranoid and delusional disorders, dyskinetic disorders (e.g. Parkinson's disease, neuroleptic induced Parkinsonism, tardive dyskinesias) anxiety, sexual dysfunction, sleep disorders, emesis, aggression, autism, pain, ophthalmological diseases (e.g. glaucoma etc.). DETAILED DESCRIPTION OF THE INVENTION The present invention relates to new compounds of formula (I) wherein X represents a nitrogen atom or CH group; Y represents a bond when X stands for nitrogen, or an oxygen atom or NH or CH 2 or OCH 2 group when X stands for CH group; R 1 , R 2 , R 3 may be the same or different and represent independently a substituent selected from hydrogen, halogen, C 1-6 -alkyl, C 1-6 alkoxy, cyano, hydroxy, trifluoromethyl, C 1-6 -alkylsulfonyloxy, trifluoromethanesulfonyloxy, C 1-6 -alkanoyloxy, amino, alkylamino, alkanoylamino, alkylsulfonylamino, arylsulfonylamino, aminocarbonyl, carboxy, N-hydroxycarmamimidoyl, carbamimidoyl, hydroxycarbamoyl, thiocarbamoyl, sulfamoyl, mono or bicyclic heterocyclic group or optionally substituted phenyl, or two adjacent groups of R 1 , R 2 and R 3 may combine to form an optionally substituted fused mono or bicyclic heterocyclic group; Q represents a dialkylamino group or an optionally substituted C 1-6 -alkyl, aryl, heteroaryl, aralkyl or heteroaralkyl group and/or geometric isomers and/or stereoisomers and/or diastereomers and/or salts and/or hydrates and/or solvates thereof. When Q represents aryl, the aryl moiety may be selected from an optionally substituted mono- or bicyclic aryl namely phenyl or naphthyl group. A heteroaryl ring in the meaning of Q may be monocyclic or bicyclic ring. The monocyclic heteroaryl ring may be an optionally substituted 5- or 6-membered aromatic heterocyclic group containing 1 to 4 heteroatoms selected from O, N or S. Examples of 5- and 6-membered heterocyclic groups include furyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, pyridyl, triazolyl, triazinyl, pyridazyl, pyrimidinyl, isothiazolyl, isoxazolyl, pyrazinyl and pyrazolyl, preferably pyridyl and thienyl. Examples of bicyclic heteroaromatic groups include indazolyl, indolyl, benzofuranyl, benzothienyl, benzothiazolyl, benzimidazolyl, benzoxazolyl, benzisoxazolyl, benzisothiazolyl, quinolinyl, quinoxolinyl, quinazolinyl, cinnolinyl or isoquinolinyl, preferably quinolinyl, benzofuranyl, benzothiophenyl, benzthiazolyl, benzimidazolyl and indolyl group. The substituents of substituted C 1-6 -alkyl, aryl, heteroaryl, aralkyl or heteroaralkyl groups in the meaning of Q are selected from hydrogen, halogen, cyano, trifluoromethyl, C 1-6 -alkyl, C 1-6 -alkoxy, C 1-6 -alkanoyl, methylenedioxy, C 1-6 -alkylamino, C 1-6 -alkanoylamino, optionally substituted aroyl, aryloxy, aminosulfonyl, arylsulfonylamido, optionally substituted mono or bicyclic aromatic or heteroaromatic ring, wherein the aryl may have the same meaning as mentioned above. The substituents of C 1-6 -alkanoyloxy in the meaning of R 1 , R 2 and R 3 are selected from hydrogen or halogen. The amino, aminoalkyl, aminocarbonyl, N-hydroxycarbamimidoyl, carbamimidoyl, hydroxycarbamoyl, thiocarbamoyl and sulfamoyl groups in the meaning of R 1 , R 2 and R 3 may optionally be substituted on the N atom. The mono or bicyclic heterocyclic group in the meaning of R 1 , R 2 and R 3 may be saturated or unsaturated containing 1 to 4 heteroatoms selected from O, N or S. In the compounds of formula (I) an alkyl group or moiety in alkoxy, alkanoyl, alkanoylamino, alkanoyloxy groups may be straight or branched included methyl, ethyl, n-propyl, n-butyl, n-pentyl-, n-hexyl and branched isomers thereof such as isopropyl, t-butyl, sec-butyl, and the like. The halogen substituent(s) in the compounds of formula (I) may be fluorine, chlorine, bromine or iodine, preferably fluorine, bromine and chlorine. The compounds of formula (I) can exist in the form of cis- and trans-isomers with respect to the configuration of the cyclohexane ring. These and their mixtures are likewise within the scope of the present invention. Preferably the compounds of the invention are in the trans configuration. The invention also relates to the salts of compounds of formula (I) formed with acids. Both organic and inorganic acids can be used for the formation of acid addition salts. Suitable inorganic acids can be for example hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid. Representatives of monovalent organic acids can be for example formic acid, acetic acid, propionic acid, and different butyric acids, valeric acids and capric acids. Representatives of bivalent organic acids can be for example oxalic acid, malonic acid, maleic acid, fumaric acid and succinic acid. Other organic acids can also be used, such as hydroxy acids for example citric acid, tartaric acid, or aromatic carboxylic acids for example benzoic acid or salicylic acid, as well as aliphatic and aromatic sulfonic acids for example methanesulfonic acid, naphtalenesulfonic acid and p-toluenesulfonic acid. Especially valuable group of the acid addition salts is in which the acid component itself is physiologically acceptable and does not have therapeutical effect in the applied dose or it does not have unfavourable influence on the effect of the active ingredient. These acid addition salts are pharmaceutically acceptable acid addition salts. The reason why acid addition salts, which do not belong to the pharmaceutically acceptable acid addition salts belong to the present invention is, that in given case they can be advantageous in the purification and/or isolation of the desired compounds. Solvates and hydrates of compounds of formula (I) are also included within the scope of the invention. As the invention relates also to the salts of compounds of formula (I) formed with acids, especially the salts formed with pharmaceutically acceptable acids, the meaning of compound of formula (I) is either the free base or the salt even if it is not referred separately. Preferred compounds of the invention are those compounds of formula (I) wherein X represents a nitrogen atom or CH group; Y represents a bond when X stands for nitrogen, or an oxygen atom or NH or CH 2 or OCH 2 group when X stands for CH group; R 1 R 2 , R 3 may be the same or different and represent independently hydrogen, alkyl, alkoxy, halogen, cyano, aminocarbonyl, trifluoromethyl, amino, alkylamino, alkanoylamino, alkylsulfonylamino, arylsulfonylamino, aminocarbonyl, carboxy, N-hydroxycarmamimidoyl, carbamimidoyl, hydroxycarbamoyl, thiocarbamoyl, sulfamoyl, mono or bicyclic heterocyclic group or optionally substituted phenyl, or two adjacent groups of R 1 , R 2 and R 3 may combine to form an optionally substituted fused mono or bicyclic heterocyclic group; Q represents dialkylamino, optionally substituted phenyl, biphenyl, pyridyl, thienyl, alkyl or quinolinyl; and/or geometric isomers and/or stereoisomers and/or diastereomers and/or salts and/or hydrates and/or solvates thereof. Especially preferred compounds of the invention are those compounds of formula (I) wherein X represents a nitrogen atom or CH group; Y represents a bond when X stands for nitrogen, or CH 2 group when X stands for CH group; R 1 , R 2 , R 3 may be the same or different and represent independently hydrogen, fluorine, bromine, chlorine atoms or cyano, trifluoromethyl, methyl, methoxy, ethoxy, aminocarbonyl, amino, alkylamino, alkanoylamino, alkylsulfonylamino, arylsulfonylamino, aminocarbonyl, carboxy, N-hydroxycarmamimidoyl, carbamimidoyl, hydroxycarbamoyl, thiocarbamoyl, sulfamoyl, mono or bicyclic heterocyclic group or optionally substituted phenyl, or two adjacent groups of R 1 , R 2 and R 3 may combine to form an optionally substituted fused mono or bicyclic heterocyclic group; Q represents C 1-4 alkyl, dimethylamino, biphenyl, alkylphenyl, alkoxyphenyl, halophenyl, nitrophenyl, trifluoromethylphenyl or aminocarbonylmethylphenyl, pyridyl, or quinolinyl; and/or geometric isomers and/or stereoisomers and/or diastereomers and/or salts and/or hydrates and/or solvates thereof. Furthermore subjects of the present invention are the synthesis of compounds of formula (I) and the chemical and pharmaceutical manufacture of medicaments containing these compounds, as well as the process of treatments and/or prevention with these compounds, which means administering to a mammal to be treated—including human—effective amount/amounts of compounds of formula (I) of the present invention as such or as medicament. The present invention also provides processes for preparing compounds of formula (I) by forming a sulfonamide bond between a sulfochloride of formula (II) or a derivative thereof wherein the meaning of Q is as described above for the formula (I) and an amine of formula (III) or a derivative thereof wherein the meaning of R 1 , R 2 , R 3 , X and Y are as described above for the formula (I). The sulfonamide bond formation may be carried out by known methods, preferably by reacting a sulfochloride of formula (II) with an amine of formula (III) in the presence of a base. The amine of formula (III) as a base or as a salt formed with an acid is dissolved in an appropriate solvent (for example chlorinated hydrocarbons, hydrocarbons, tetrahydrofuran, dimethylformamide or acetonitrile), base is added (for example triethylamine) followed by the appropriate sulfochloride. The reaction is carried out preferably between −10° C. and ambient temperature. The reactions are followed by thin layer chromatography. The necessary reaction time is about 6-24 h. The work-up of the reaction mixture can be carried out by different methods. The products can be purified for example by crystallization or, if necessary, by column chromatography. Those having skill in the art can recognize that the starting materials may be varied and additional steps can be employed to produce compounds encompassed by the present invention, as demonstrated by the Examples. In some cases protection of certain reactive functionalities may be necessary to achieve some of the above transformations. In general the need for such protecting groups is apparent to those skilled in the art as well as the conditions necessary to attach and remove such groups. The structures of all intermediates and end products were elucidated by IR, NMR and mass spectroscopy. The sulfochlorides of formula (II) are either commercially available or can be synthesized by different known methods, e.g. J.Chem.Soc., 1992, 4889-4898; J.Med.Chem.,1989, 32, 2436-2442; J.Med.Chem., 1993, 36, 320-330. The amines of formula (III) may be prepared by alkylation of compounds of formula (IV) or a derivative thereof wherein the meaning of R 1 , R 2 , R 3 , X and Y are as described above for formula (I), by known methods: e.g. J.Med.Chem., 2000, 43, 1878-1885. The amines of formula (IV) are either commercially available or can be synthesized by different known methods: e.g. where X stands for CH and Y stands for NH group: Synlett, 1961, 537; where X stands for CH and Y stands for oxygen or OCH 2 : J.Med.Chem., 1974, 17, 1000; where X stands for CH and Y stands for CH 2 group: U.S. Pat. No. 3,632,767; WO 97/23216; FR 2,534,580; where Y is a bond and X stands for nitrogen: Tetrahedron, 1999, 55, 13285-13300; J.Med.Chem., 1989, 32, 1052-1056; U.S. Pat. No. 2,922,788. The separation of cis- and trans-isomers either of compounds of formula (I) or of formula (III) or the protected derivatives of the latter is carried out by conventional methods, e.g. by chromatography and/or crystallization, or the cis- or trans-isomers of formula (III) can be prepared using pure cis- or trans-isomers as an alkylating agents. The obtained derivatives of formula (I) can be transformed into an other compound of formula (I) in given case by introducing further substituent(s) and/or modifying and/or removing the existing one(s). For example cleaving the methyl group from a methoxy group which stands for R 1 and/or R 2 and/or R 3 leads to phenol derivatives. The cleavage of methyl group can be carried out for example with boron tribromide in dichloromethane. The compounds of formula (I) containing cyano groups can be for example transformed to amides by hydrolysing them with hydrogenperoxide in dimethylsulfoxide, or to amidines by reacting them first with gaseous hydrogenchloride in ether, then by reacting the iminoester obtained with ammonia, etc. The sulfonamide derivatives of formula (I) can also be prepared on solid support: i) A compound of formula (VI) wherein R 6 represents hydrogen or a protecting group e.g. silyl or tetrahydropyranyl was attached to a polystyrene resin of formula (V), wherein R 4 and R 5 can be the same or different and represent hydrogen or methoxy group with the exception R 4 ═R 5 ═H, by reductive amination with a reducing agent e.g. NaB(OAc) 3 H or NaBH 3 CN; ii) halogenation, preferably bromination, of the terminal hydroxy group of a compound of formula (VII), wherein the meaning of R 6 is as described above for formula (VI), with a halogenation agent e.g. PPh 3 Br 2 , PPh 3 I 2 , or if it was protected, the protecting group had been removed before the halogenation, which results a solid phase compound of formula (VIII) wherein Z represents halogen, preferably bromide and the meaning of R 4 and R 5 is as described above for formula (V); iii) sulfonylation a compound of formula (VIII) with different sulfochlorides of formula (II) wherein the meaning of Q is as described above for formula (I) (the first combinatorial step); iv) alkylation with a compound of formula (IX) wherein the meaning of Z, R 4 and R 5 are as described above for the formula (VIII) and the meaning of Q is as described above for formula (I) of a secondary amine of formula (IV) wherein the meaning of R 1 , R 2 , R 3 , X and Y are as described above for the formula (I) (the second combinatorial step); v) releasing the products of formula (I) from the solid-phase compounds of formula (X) wherein the meaning of Q, R 1 , R 2 , R 3 , X and Y are as described above for the formula (I) and of R 4 and R 5 are as described above for the formula (V) by acidic cleavage. This synthetic route is represented by FIG. 1. The invention also relates to the pharmaceutical compositions containing the compounds of formula (I) as active ingredient. The compounds of formula (I) of the present invention have been found to exhibit affinity for dopamine receptors, in particular the D 3 receptor, and are expected to be useful in the treatment of disease states which require modulation of such receptors, e.g. psychotic or ophthalmological disorders. The compounds of formula (I) have been found to have greater affinity for dopamine D 3 than for D 2 receptors. The compounds of formula (I) may therefore advantageously be used as selective modulators of D 3 receptors. Dysfunction of the dopaminergic neurotransmitter system is involved in the pathology of several neuropsychiatric disorders such as schizophrenia, Parkinson's disease and drug abuse. The effect of dopamine is mediated via at least five distinct dopamine receptors belonging to the D 1 -(D 1 , D 5 ) or the D 2 -(D 2 , D 3 , D 4 ) families. D 3 receptors have been shown to have characteristic distribution in the cerebral dopaminergic systems. Namely, high densities were found in certain limbic structures such as nucleus accumbens and islands of Calleja. Therefore, selective targeting of the D 3 receptors may be a promising approach for more selective modulation of dopaminergic functions and consequently for successful therapeutic intervention in several abnormalities, such as schizophrenia, emotional or cognitive dysfunctions and addiction (Sokoloff, P. et al: Nature, 1990, 347, 146; Schwartz, J.-C. et al.: Clin. Neuropharmacol., 1993, 16, 295; Levant, B.: Pharmacol. Rev., 1997, 49, 231.), addiction (Pilla, C. et al: Nature, 1999, 400, 371) and Parkinson's disease (Levant, B. et al.: CNS Drugs, 1999, 12, 391) or pain (Levant, B. et al.: Neurosci. Lett., 2001, 303, 9). Dopamine D 3 receptors are also implicated in regulation of intraocular pressure and agonists at these receptors are capable of decreasing the intraocular pressure (Chu, E. et al: J. Pharmacol. Exp. Ther., 2000, 292, 710), thus D 3 receptors agonists can be useful for the treatment of glaucoma. Certain compounds of formula (I) have been found to be dopamine D 3 receptor antagonist, others may be agonists or partial agonists. In a further aspect of the present invention provides a method of treating conditions which require modulation of dopamine D 3 receptors, for example psychoses, for example in the treatment of schizophrenia, schizo-affective disorders, psychotic depression, mania, paranoid and delusional disorders, dyskinetic disorders such as Parkinson's disease, neuroleptic induced parkinsonism, depression, anxiety, memory disorders, sexual dysfunction, drug dependency and ophthalmological disorders which comprises administering to a subject in need thereof an effective amount of a compound of formula (I) or a physiologically acceptable salt thereof. The invention also provides the use of a compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof in the manufacture of a medicament for the treatment of conditions which require modulation of dopamine D 3 receptors. A preferred use for D 3 agonists or partial agonists according to the present invention is in the treatment of drug abuse (such as cocaine abuse etc.) and eye diseases (such as glaucoma). A preferred use for D 3 antagonists according to the present invention is in the treatment of schizophrenia, schizo-affective disorders, psychotic depression, mania, paranoid and delusional disorders, dyskinetic disorders such as Parkinson's disease, neuroleptic induced parkinsonism, depression, anxiety, memory disorders, sexual dysfunction, drug abuse, pain. For use in medicine, the compounds of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof are usually administered as a standard pharmaceutical composition. The present invention therefore provides in a further aspect pharmaceutical compositions comprising a new compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof and one or more physiologically acceptable carrier(s). The compounds of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof may be administered by any convenient method, for example by oral, parental, buccal, sublingual, nasal, rectal or transdermal administration and the pharmaceutical compositions adapted accordingly. The compounds of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof and the physiologically acceptable salts thereof which are active when given orally can be formulated as liquids or solids, for example syrups, suspensions or emulsions, tablets, capsules and lozenges. A liquid formulation of the compounds of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof generally consists of a suspension or solution of the compound of formula (I) or physiologically acceptable salts thereof in a suitable liquid carrier(s) for example an aqueous solvent, such as water, ethanol or glycerine, or a non-aqueous solvent, such as polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring or colouring agent. A composition in the solid form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations. Examples of such carriers include magnesium stearate, starch, lactose, sucrose, cellulose etc. A composition in the solid form of a capsule can be prepared using routine encapsulation procedures. For example, pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatine capsule; alternatively, a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), for example aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatine capsule. Typical parenteral compositions consist of a solution or suspesion of the compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof or physiologically acceptable salt thereof in a steril aqueous carrier or parenterally acceptable oil, for example polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration. Compositions of the present invention for nasal administration containing a compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof may conveniently be formulated as aerosols, drops, gels and powders. Aerosol formulations of the present invention typically comprise a solution or fine suspension of the compound of formula (I) in a physiologically acceptable aqueous or non-aqueous solvent and are usually presented in a single or multidose quantities in steril form is a sealed container, which can take the form of a cartridge or refill for use with an atomising device. Alternatively, the sealed container may be a unitary dispensing device, such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve which is intended for disposal once the contents of the container have been exhausted. Where the dosage form comprises an aerosol dispenser, it will contain a propellant which can be a compressed gas, such as compressed air or an organic propellant, such as a fluorochlorohydrocarbon. The aerosol dosages form can also take the form of a pump-atomiser. Compositions of the present invention containing a compound of formula (I) suitable for buccal or sublingual administration include tablets, lozenges and pastilles, wherein the active ingredient is formulated with a carrier, such as sugar and acacia, tragacanth, or gelatine and glycerin etc. Compositions of the present invention containing a compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof for rectal administration are conveniently in the form of suppositories containing a conventional supposiory base, such as cocoa butter. Compositions of the present invention containing a compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof for transdermal administration include ointments, gels and patches. The compositions of the present invention containing a compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof is preferably in the unit dose form, such as tablet, capsule or ampoule. Each dosage unit of the present invention for oral administration contains preferably from 1 to 250 mg of a compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof calculated as a free base. Each dosage unit of the present invention for parenteral administration contains preferably from 0.1 to 25 mg of a compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof calculated as a free base. The physiologically acceptable compounds formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof can normally be administered in a daily dosage regimen (for an adult patient) of, for example, an oral dose between 1 mg and 500 mg, preferably between 10 mg and 400 mg, e.g. between 10 and 250 mg or an intravenous, subcutaneous, or intramuscular dose of between 0.1 mg and 100 mg, preferably between 0.1 mg and 50 mg, e.g. between 1 and 25 mg of the compound of formula (I) and/or geometric isomers and/or stereoisomers and/or diastereomers and/or physiologically acceptable salts and/or hydrates and/or solvates thereof calculated as the free base. The compound of the present invention can be administered 1 to 4 times per day. The compound of the present invention can suitably be administered for a period of continous therapy, for example for a week or more. Receptor Binding Assays 1. D 3 receptor binding Binding study was carried out on rat recombinant D 3 receptors expressed in Sf9 cells using [ 3 H]-spiperone (0.4 nM) as ligand and haloperidol (10 μM) for determination of non-specific binding. The assay was performed according to Research Biochemical International assay protocol for rD 3 receptor (Cat. No. D-181). 2. D 2 Receptor Binding Binding of [ 3 H]-spiperone (0.5 nM) to rat striatal tissue was measured according to the method of Seeman (J. Neurochem., 1984, 43 221-235). The non-specific binding was determined in the presence of (±)-sulpiride (10 μM). D 3 and D 2 receptor binding data of compounds of the present invention are listed in Table 1. TABLE 1 D3-IC 50 D2-IC 50 code (nM) (nM) 70001485 5.5 2586 70001488 4.3 245 70001492 2.0 65 70001588 2.5 102 70001589 3.0 16 70001596 0.6 110 70001766 5.3 128 70001788 1.5 290 70001934 1.0 109 70001935 0.3 29 70001686 3.9 345 70001875 2.8 66 The most prominent side effects of the first generation antipsychotic compounds (e.g. chlorpromazine and haloperidol) with preferential blockade at dopamine D 2 , and alpha-1 receptors, are the tardive dyskinesia and orthostatic hypotension. The former one is the result of blockade of D 2 receptors in the basal ganglia whereas the latter is the consequence of antagonism of alpha-1 receptors. Compounds in Table 1 are potent ligands at D 3 receptors (IC-50 values are between 0.3 and 5.5 nM) and show 5 to 470 fold selectivity over D 2 receptors. Moreover, the compounds have beneficial profile in terms of potency on D 3 receptors and selectivity towards D 2 . It is therefore anticipated that no or greatly diminished adverse effects related to D 2 receptors will occur in the course of therapeutical application of compounds of the present invention. The invention is further illustrated by the following non-limiting examples. EXAMPLE 1 1-(3-cyano-5-trifluoromethyl-phenyl)-piperazine 2.42 g (13 mmol) 3-fluoro-5-trifluoromethyl-benzonitrile and 6.0 g (70 mmol) piperazine was dissolved in 50 ml dimethylsulfoxide and the solution was refluxed for one day. The mixture was poured into 200 ml of water and extracted with diethylether (3×100 ml). The organic layers were washed with saturated sodium chloride solution, then dried and evaporated to dryness in vacuo giving 2.96 g (yield 89.2%) of the title compound, melting at 85-7° C. EXAMPLE 1 Trans-(4-{2-[4-(3-cyano-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester 0.63 g (2.5 mmol) of 1-(3-cyano-5-trifluoromethyl-phenyl)-piperazine and 0.6 g (2.5 mmol) of trans-2-{1-[4-(N-tert-butyloxycarbonyl)amino]cyclohexyl}-acetaldehyde were dissolved in dichloroethane (35 ml), 0.79 g (3.7 mmol) sodium triacetoxyborohydride was added portionswise and the reaction mixture was stirred for 20 hours at ambient temperature, then 20% potassium carbonate solution in water (20 ml) was added. The organic layer was separated, dried and evaporated to dryness in vacuo. The precipitate was recrystallized from acetonitrile to give the title compound 1.03 g (yield 85.8%), m.p.: 139-140° C. The Following Compounds were Prepared in a Similar Manner to Example 1: Trans-(4-{2-[4-(3-methoxy-biphenyl)-4-yl)-piperazin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 171-2° C. Trans-(4-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 130-2° C. Trans-(4-{2-[4-(2,3-dichloro-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 144-5° C. Trans-(4-{2-[4-(3-trifluoromethyl-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 107° C. Trans-(4-{2-[4-(3-fluoro-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 128° C. Trans-(4-{2-[4-(3-cyano-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 115-6° C. Trans-(4-{2-[4-(3-trifluoromethyl-phenylamino)-piperidin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 112-3° C. Trans-(4-{2-[4-(3-trifluoromethyl-phenylmethoxy)-piperidin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 107° C. Trans-(4-{2-[4-(3-trifluoromethyl-phenoxy)-piperidin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester, m.p.: 118-9° C. EXAMPLE 2 Trans-3-{4-[2-(4-amino-cyclohexyl)-ethyl]-piperazin-1-yl}-5-trifluoromethyl-benzonitrile 1.03 g (2.1 mmol) trans-(4-{2-[4-(3-cyano-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-carbamic acid tert-butyl ester was deprotected at 10° C. using 10 ml ethylacetate saturated with gaseous hydrochloric acid, the precipitate was filtered giving 0.94 g (yield 98%) dihydrochloride salt of the title compound, melting above 260° C. The Following Compounds were Prepared in a Similar Manner to Example 2: Trans-4-{2-[4-(3-methoxy-biphenyl-4-yl)-piperazin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: >280° C. Trans-4-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 280° C. Trans-4-{(2-[4-(2,3-dichloro-phenyl)-piperazin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 264-5° C. Trans-4-{2-[4-(3-trifluoromethyl-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 268° C. Trans-4-{2-[4-(3-fluoro-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 286-7° C. Trans-4-{2-[4-(3-cyano-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 257-8° C. Trans-4-{2-[4-(3-trifluoromethyl-phenylamino)-piperidin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 260-4° C. Trans-4-{2-[4-(3-trifluoromethyl-phenylmethoxy)-piperidin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 262° C. Trans-4-{2-[4-(3-trifluoromethyl-phenoxy)-piperidin-1-yl]-ethyl}-cyclohexylamine dihydrochloride, m.p.: 294° C. EXAMPLE 3 Trans-N-(4-{2-[4-(3-cyano-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-pyridin-3-sulfonamide (70001503) 0.38 g (1 mmol) of trans-3-{4-[2-(4-amino-cyclohexyl)-ethyl]-piperazin-1-yl}-5-trifluoromethyl-benzonitrile was dissolved in dichloromethane (30 ml), 0.42 ml (3 mmol) triethylamine was then added followed by 0.24 g (1.1 mmol) of pyridine-3-sulfochloride hydrochloride. The mixture was stirred for 24 hours, washed twice with 10% sodium bicarbonate solution, dried and evaporated to dryness in vacuo. The residue was purified on silica gel eluting with 10% ethanol/chloroform, then converted to the dihydrochloride salt of the title compound. 0.32 g (yield 54%), melting at 194-5° C. The Following Compounds were Prepared in a Similar Manner to Example 3: Trans-N′-(4-{2-[4-(3-methoxy-biphenyl-4-yl)-piperazin-1-yl]-ethyl}-cyclohexyl)-N,N-dimethyl hydrochloride, m.p.: 243-6° C. (70001488) Trans-4-chloro-N-(4-{2-[4-(3-cyano-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide hydrochloride, m.p.: 260-2° C. (70001492) Trans-4-chloro-N-(4-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide hydrocloride, m.p.:223° C. (70001552) Trans-N-(4-{2-[4-(3-methoxy-biphenyl-4-yl)-piperazin-1-yl]-ethyl}-cyclohexyl)-3-pyridinesulfonamide dihydrochloride, m.p.: 219° C. (70001737) Trans-5-chloro-N-(4-{2-[4-(3-cyano-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-2-thiophenesulfonamide hydrochloride, m.p.: 181° C. (70001766) Trans-N′-(4-{2-[4-(3-cyano-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-N,N-dimethyl-sulfamide, m.p.: 83-5° C. (70001788) Trans-N-(4-{2-[4-(3-methoxy-biphenyl-4-yl)-piperazin-1-yl]-ethyl}-cyclohexyl)-buthanesulfonamide hydrochloride, m.p.: 215-8° C. (70001485) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-buthanesulfonamide hydrochloride, m.p.: 228-9° C. (70001596) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-4-morpholinepropanesulfonamide dihydrochloride, m.p.: 218-20° C. (70001934) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-3-pyridinesulfoamide dihydrochloride, m.p.: 183-6° C. (70001935) Trans-N-(4-{2-[4-(2,3-dichloromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-3-pyridinesulfonamide dihydrochloride, m.p.: 272-4° C. (70002127) Trans-4-bromo-N-(4-{2-[4-(3-trifluoromethyl-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide m.p.: 145° C. (70001539) Trans-4-chloro-N-(4-{2-[4-(3-fluoro-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide m.p.: 109° C. (70001686) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-3-pyridinesulfonamide dihydrochloride, m.p.: 102° C. (70002060) Trans-4-chloro-N-(4-{2-[4-(3-trifluoromethyl-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide m.p.: 150-1° C. (70001317) Trans-4-chloro-N-(4-{2-[4-(3-cyano-phenylmethyl)-piperidin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide hydrochloride, m.p.: 101° C. (70001775) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenylamino)-piperidin-1-yl]-ethyl}-cyclohexyl)-trifluoroethanesulfonamide hydrochloride, m.p.: 198° C. (70001595) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenylamino)-piperidin-1-yl]-ethyl}-cyclohexyl)-buthanesulfonamide hydrochloride, m.p.: 198° C. (70001588) Trans-4-chloro-N-(4-{2-[4-(3-trifluoromethyl-phenylamino)-piperidin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide hydrochloride, m.p.: 237-9° C. (70001589) Trans-N′-(4-{2-[4-(3-trifluoromethyl-phenylamino)-piperidin-1-yl]-ethyl}-cyclohexyl)-N,N-dimethylsulfamide hydrochloride, m.p.: 169-71° C. (70001590) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenylmethoxy)-piperidin-1-yl]-ethyl}-cyclohexyl)-3-pyridinesulfonamide dihydrochloride, m.p.: 73° C. (70001873) Trans-N-(4-{2-[4-(3-trifluoromethyl-phenoxy)-piperidin-1-yl]-ethyl}-cyclohexyl)-3-pyridinesulfonamide dihydrochloride, m.p.: 98° C. (70001875) EXAMPLE 4 Trans-N-{4-[2-[4-(3-aminocarbonyl-5-trifluoromethyl-phenyl)-1-piperizinyl]-ethyl]-cyclohexyl}-3-pyridinesulfonamide (70002080) 0.37 g (0.7 mmol) of trans-N-(4-{2-[4-(3-cyano-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-pyridine-3-sulfonamide was dissolved in 2 ml dimethylsulfoxide, 80 mg K 2 CO 3 was added and 0.15 ml of 30% H 2 O 2 was dropped in while keeping the temperature at 20° C. After stirring for 2 h 20 ml of water was added, the precipitate filtered, washed with water giving the title compound, melting point:191° C. (0.2 g; 53%). EXAMPLE 5 Polymer-bound trans-2-(4-amino-cyclohexyl)-ethanol 5 g of 2-(4-formyl-3-methoxy)phenoxyethyl polystyrene (1.12 mmol/g) resin was suspended in 150 ml of dichloromethane. To the shaken suspension 3.5 g (4.5 eq.) of trans-2-(4-amino-cyclohexyl)-ethanol was added, followed by dropwise addition of 4.5 ml of acetic acid. 1.2 g (1 eq) of NaBH(OAc) 3 was added in portions within 15 minutes. After 3 hours of shaking another 0.6 g (0.5 eq.) of NaBH(OAc) 3 was added in one portion. The shaking was continued overnight. The mixture was filtered and the resin was washed in sequence with the following solvents (100 ml, twice with each): dichloromethane, methanol, 10% triethylamine in dimethylformamide, methanol, dimethylformamide, tetrahydrofuran, diethylether. EXAMPLE 6 Polymer-bound trans-2-(4-amino-cyclohexyl)-ethylbromide The freshly prepared mixture of 1.45 g (5 eq.) triphenylphosphine and 0.28 ml (5 eq.) Br 2 in 20 ml of dichloromethane was added to 1 g of the polymer-bound trans-2-(4-amino-cyclohexyl)-ethanol and 0.38 g (5 eq.) 1-H-imidazole. The suspension was shaken for 18 hours, filtered and the resin was washed in sequence with the following solvents (20 ml, twice with each): dichloromethane, methanol, 10% triethylamine in dimethylformamide, methanol, dimethylformamide, tetrahydrofuran, diethylether. EXAMPLE 7 Polymer-bound trans-4-bromo-N-[4-(2-bromo-ethyl)-cyclohexyl]-benzenesulfonamide To 0.1 g of polymer-bound trans-2-(4-amino-cyclohexyl)-ethylbromide in 2.5 ml of tetrahydrofuran 10 mg dimethylaminopyridine, 0.07 ml (5 eq.) triethylamine and 0.13 g (5 eq.) 4-bromobenzenesulfochloride were added. The mixture was shaken for 18 hours, filtered and the resin was washed in sequence with the following solvents (10 ml, twice with each): tetrahydrofuran, methanol, tetrahydrofuran, dimethylformamide, methanol, dichloromethane, methanol, dimethylformamide. EXAMPLE 8 Polymer-bound trans-4bromo-N-(4-{2-[4-(2-methoxy-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide To the polymer-bound Trans-4-N-[4-(2-bromo-ethyl)-cyclohexyl]-benzenesulfonamide in 2 ml dimethylformamide 65 mg (5 eq.) 1-(2-methoxyphenyl)-piperazine and 0.065 ml (5 eq.) diisopropylethylamine were added and the mixture was shaken for 18 hours at 90° C. The resin was filtered and washed in sequence with the following solvents (10 ml, twice with each): dimethylformamide, methanol, dimethylformamide, methanol, dimethylformamide, methanol, dichloromethane. EXAMPLE 9 Trans-4-bromo-N-(4-{2-[4-(2-methoxy-phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide The product was cleaved from the resin with shaking in 2 ml of 10% TFA in dichloromethane for two hours. The mixture was filtered and washed with the following solvents (10 ml, twice with each): dichloromethane, methanol, dichloromethane, and methanol. The filtrate was evaporated in vacuo to give the title product. The LC/MS analysis were performed using an HP 1100 binary gradient system, controlled by ChemStation software. HP diode array detector was used to acquire UV spectra at λ=240 nm. Analytical chromatographic experiments were made on Discovery C 16 -Amide, 5 cm×4.6 mm×5 μm column with a flow rate of 1 ml/min for qualification (purity, capacity factor). All experiments were performed using HP MSD single quadruple mass spectrometer equipped with an electrospray ionisation source to determine the structure. [k′=t R -t 0 /t 0 t R =retention time t 0 =eluent retention time] k′=capacity factor The following compounds in Table 2 were prepared in a similar manner to Example 5-9: TABLE 2 MS found ID NAME MW MW k′ 80001076 2,5-Dichloro-N-(4-{2-[4-(3-trifluoromethyl-phenoxy)- 579.5 580.4 4.272 piperidin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide 80001099 N-(4-{2-[4-(3-Bromo-phenylamino)-piperidin-1-yl]-ethyl}- 550.6 551.4 3.842 cyclohexyl)-4-methoxy-benzenesulfonamide 80001109 4-Chloro-N-(4-{2-[4-(3-trifluoromethyl-phenyl)- 530.0 530.5 3.986 piperazin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide 80001110 N-(4-{2-[4-(2-Methoxy-phenyl)-piperazin-1-yl]-ethyl}- 502.6 503.5 3.545 cyclohexyl)-4-nitro-benzenesulfonamide 80001121 N-(4-{2-[4-(2,3-Dichloro-phenyl)-piperazin-1-yl]-ethyl}- 541.5 542.5 3.942 cyclohexyl)-2-nitro-benzenesulfonamide 80001137 N-(4-{2-[4-(3-Cyano-5-trifluoromethyl-phenyl)-piperazin- 538.6 539.5 3.859 1-yl]-ethyl}-cyclohexyl)-4-fluoro-benzenesulfonamide 80001138 N-[4-(4-{2-[4-(4-Bromo-2,3-dimethyl-phenyl)-piperazin- 591.6 592.5 3.808 1-yl]-ethyl}-cyclohexylsulfamoyl)-phenyl]-acetamide 80001139 N-(4-{2-[4-(3-Bromo-phenyl)-piperazin-1-yl]-ethyl}- 548.6 549.5 4.036 cyclohexyl)-2,4,6-trimethyl-benzenesulfonamide 80001141 Biphenyl-4-sulfonic acid (4-{2-[4-(4-bromo-2-ethoxy- 626.7 627.6 4.269 phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-amide 80001153 N-(4-{2-[4-(2,5-Dichloro-phenylamino)-piperidin-1-yl]- 555.5 556.5 4.015 ethyl}-cyclohexyl)-4-nitro-benzenesulfonamide 80001168 Biphenyl-4-sulfonic acid (4-{2-[4-(5-chloro-2-methoxy- 568.2 568.6 4.104 phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-amide 80001171 N-(4-{2-[4-(3-Chloro-phenyl)-piperazin-1-yl]-ethyl}- 492.1 492.2 3.631 cyclohexyl)-4-methoxy-benzenesulfonamide 80001181 N-(4-{2-[4-(3,5-Dichloro-phenyl)-piperazin-1-yl]-ethyl}- 510.5 511.5 3.939 cyclohexyl)-4-methyl-benzenesulfonamide 80001187 N-(4-{2-[4-(4-Chloro-phenyl)-piperazin-1-yl]-ethyl}- 492.1 493.1 3.598 cyclohexyl)-4-methoxy-benzenesulfonamide 80001196 N-(4-{2-[4-(4-Bromo-2-ethoxy-phenyl)-piperazin-1-yl]- 676.4 677.5 4.032 ethyl}-cyclohexyl)-4-iodo-benzenesulfonamide 80001210 3,4-Dichloro-N-(4-{2-[4-(3-methoxy-biphenyl-4-yl)- 602.6 603.5 4.230 piperazin-1-yl]-ethyl}-cyclohexyl)-benzenesulfonamide 80001226 Quinoline-8-sulfonic acid (4-{2-[4-(3-trifluoromethyl- 546.7 547.6 3.725 phenyl)-piperazin-1-yl]-ethyl}-cyclohexyl)-amide 80001233 N-[4-(4-{2-[4-(3,5-Dichloro-phenyl)-piperazin-1-yl]- 553.5 554.5 3.555 ethyl}-cyclohexylsulfamoyl)-phenyl]-acetamide 80001238 N-(4-{2-[4-(5-Chloro-2-methoxy-phenyl)-piperazin-1-yl]- 510.1 510.5 3.521 ethyl}-cyclohexyl)-4-fluoro-benzenesulfonamid 80001239 N-[4-(4-{2-[4-(3-Chloro-phenyl)-piperazin-1-yl]-ethyl}- 519.1 519.6 3.273 cyclohexylsulfamoyl)-phenyl]-acetamide 80001252 Biphenyl-4-sulfonic acid (4-{2-[4-(2-fluoro-phenyl)- 521.7 522.6 3.985 piperazin-1-yl]-ethyl}-cyclohexyl)-amide 80001255 N-(4-{2-[4-(2-Fluoro-phenyl)-piperazin-1-yl]-ethyl}- 475.6 476.6 3.325 cyclohexyl)-4-methoxy-benzenesulfonamide 80001262 N-(4-{2-[4-(2-Fluoro-phenyl)-piperazin-1-yl]-ethyl}- 459.6 460.5 3.476 cyclohexyl)-4-methyl-benzenesulfonamide 80001264 N-(4-{2-[4-(5-Chloro-2-methoxy-phenyl)-piperazin-1-yl]- 560.1 560.5 3.804 ethyl}-cyclohexyl)-3-trifluoromethyl- benzenesulfonamide 80001271 N-(4-{2-[4-(4-Chloro-2-methoxy-phenyl)-piperazin-1-yl]- 552.1 552.6 3.374 ethyl}-cyclohexyl)-3,4-dimethoxy-benzenesulfonamide 80001276 N-(4-{2-[4-(2-Fluoro-phenyl)-piperazin-1-yl]-ethyl}- 490.6 491.5 3.442 cyclohexyl)-3-nitro-benzenesulfonamide 80001280 N-(4-{2-[4-(2,3-Dichloro-phenyl)-piperazin-1-yl]-ethyl}- 556.5 557.5 3.713 cyclohexyl)-3,4-dimethoxy-benzenesulfonamide 80001294 N-(4-{2-[4-(4-Chloro-2-methoxy-phenyl)-piperazin-1-yl]- 506.1 506.5 3.698 ethyl}-cyclohexyl)-4-methyl-benzenesulfonamide EXAMPLE 10 Pharmaceutical formulation a) Intravenous injection Compound of formula (I) 1-40 mg Buffer to pH ca 7 Solvent/complexing agent to 100 ml b) Bolus injection Compound of formula (I) 1-40 mg Buffer to pH ca 7 Co-solvent to 5 ml Buffer: suitable buffers include e.g. citrate, phosphate, sodium hydroxide/hydrochloric acid. Solvent: typically water but may also include cyclodextrins (1-100 mg) and co-solvents, such as propylene glycol, polyethylene glycol and alcohol. c) Tablet Compound of formula (I) 1-40 mg Diluent/Filter(may also include cyclodextrins) 50-250 mg  Binder 5-25 mg Disintegrant (may also include cyclodextrins) 5-50 mg Lubricant  1-5 mg Cyclodextrin 1-100 mg  Diluent: e.g. mycrocrystalline cellulose, lactose starch. Binder: e.g. polyvinylpyrrolidone, hydroxypropylmethylcellulose. Disintegrant: e.g. sodium starch glycolate, crospovidone. Lubricant: e.g. magnesium stearate, sodium stearyl fumarate d) Oral suspension Compound of formula (I) 1-40 mg Suspending agent 0.1-10 mg   Diluent 20-60 mg  Preservative 0.01-1.0 mg    Buffer to pH ca 5-8 Co-solvent 0-40 mg Flavour 0.01-1.0 mg    Colourant 0.001-0.1 mg     Suspending agent: e.g. xanthan gum, mycrocrystalline cellulose. Diluent: e.g. sorbitol solution, typically water. Preservative: e.g. sodium benzoate. Buffer: e.g. citrate. Co-solvent: e.g. alcohol, propylene glycol, polyethylene glycol, cyclodextrin.

The present invention relates to new D 3 dopamine receptor subtype selectice ligands of formula (I) to pharmacological compositions containing the same and to their use in therapy and/or prevention of psychoses (e.g. schizophrenia, schizo-affective disorders, etc), drug (e.g. alcohol, cocaine and nicotine, opioids etc.) abuse, cognitive impairment accompanying schizophrenia, mild-to-moderate cognitive deficits, amnesia, eating disorders (e.g. bulimia nervosa, etc.), attention deficit disorders, hyperactivity disorders in children, psychotic depression, mania, paranoid and delusional disorders, dyskinetic disorders (e.g. Parkinson's diseases, neuroleptic induced Parkinson's dissases, tardive dyskinesias) anxiety, sexual dysfunction, sleep disorders, emesis, aggression, autism, pain ophthalmological diseases (e.g. glaucoma etc.).

CROSS REFERENCES TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of nonprovisional application, application Ser. No. 11/868,639 filed on Oct. 8, 2007, and bearing Confirmation Number 1460. STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT None. BACKGROUND [0002] The improved cosmetic and manicuring device as set forth in this disclosure relates to an improvement in nail brushes, and more particularly to an improved combination multi-function nail brush, nail cleaner, nail scraper, and nail cleaner/design applicator. Though described in detail herein primarily for manicuring purposes, it must be understood that the brushes associated with this device may also be brushes suitable for applying make-up, such as, but not limited to, eye shadow, eye liner, and mascara. [0003] Attention is brought to the fingernail, however, because it is an important skin appendage. It covers the dorsal surface of the terminal phalanges; i.e., the most distal bones of each finger and toe. Fingernails serve to protect the tips of the fingers and to assist in picking up small objects. They may be decorated or plain as desired by the person. [0004] Fingernails are composed of laminated layers of a protein called keratin, which is also found in one's hair and skin. As a result, fingernails should be kept in good condition and clipped regularly in a rounded or squared shape. [0005] Most of the fingernail is pink because of the underlying vascular tissue. The crescent-shaped half-moon-like white area at the bottom of the fingernail is the lunula. The lunula has a white-ish appearance because the vascular tissue under it does not show through. The lunula is the area in which new fingernail growth occurs. [0006] The cuticle is just below the lunula and the nail body is above the lunula and is basically pinkish in color. The cuticle is the tissue that overlaps the lunula at the base of the fingernail. It serves as a barrier to keep bacteria from entering one's body and protects the new keratin cells that slowly emerge as the fingernail grows [0007] As the fingernail grows, it will extend beyond the fingertip. The part of the fingernail which extends beyond the fingertip is referred to as the free edge and it also is white-ish in color or not a pink as the nail body. [0008] A “pink-and-white” fingernail has become very popular. The process to produce a pink-and-white fingernail is time-consuming, labor-intensive, and multi-faceted in that several implements are required. These include a large fingernail brush, a smaller fingernail brush, a fingernail scraper, and a fingernail cleaner. [0009] Reference is now made to FIGS. 1 through 4 in an attempt to clarify the process. The pink-and-white fingernail process first requires the manicure specialist to prepare the fingernail 60 for application of a nail tip 65 and ultimate application of acrylic on the fingernail 60 . Conventional preparation requires “roughening” the surface of the fingernail 60 typically by using a rotary sanding device designed for fingernails. A nail tip 65 is then glued onto the fingernail over and covering the free edge 63 of the fingernail 60 and can be trimmed to any desired length. [0010] A ridge or step 66 is formed where the bottom of the nail tip 65 meets the fingernail body 62 . Using the rotary sanding device, this ridge 66 is typically sanded down leaving a slight incline between the bottom of the nail tip 65 , where the ridge 66 was, and the fingernail body 62 . [0011] First the entire nail 62 is primed with a conventional primer. Next a white acrylic is applied onto the nail tip 65 by using a large nail brush and dipping it into a conventional monomer, then into a conventional white powder thereby forming a brushable acrylic paste, followed by brush application of the white acrylic paste onto the nail tip 65 . The white acrylic paste dries extremely fast and the manicure specialist typically works the white acrylic paste by brushing over it with the monomer using the large nail brush. [0012] This is typically followed by use of the smaller brush to create a crescent moon-like shape on the nail tip 65 by brushing side to side and up and down on the nail tip 65 until the exact crescent shape is perfectly achieved. [0013] The idea is to create a white crescent-moon shape on the nail tip 65 up from the ridge line 66 to the entire nail tip 65 [see FIG. 4 ]. Any excess white acrylic under the nail tip 65 is removed with a nail cleaner. Any dried white acrylic below the ridge line 66 is typically removed by sanding, filing, or scraping; a time-consuming and delicate task. [0014] Next, by using a larger nail brush, the pink acrylic component is applied. This is done by dipping the nail brush into a conventional monomer, then into a conventional pink powder thereby forming a brushable acrylic paste, followed by brush application of the pink acrylic paste downward from the nail tip 65 to, but not onto, the cuticle 71 , thereby covering the nail body 62 and lunula 61 in the process. The pink acrylic paste also dries extremely fast and the manicure specialist typically works the pink acrylic paste by brushing over it with the monomer using the large nail brush. [0015] Inasmuch as it is desired for the crescent-moon shape of the white tip to maintain its purest white color, the manicure specialist must remove any excess pink acrylic paste overlapping the white tip by sanding and filing; also a time-consuming and delicate task. Scraping, however, is a novel method and a better method provided scraping can be done quickly and before the acrylic dries. The device of the present disclosure is suited to accomplish this task. [0016] I have found that scraping is best accomplished by placing the scraper onto the white tip, adjacent to the nail 62 and over the ridge 66 , pressing down on that surface area and scraping from one side to the other side to remove all the excess pink acrylic which overlaps the white tip before the pink acrylic dries. This is repeated as necessary until the white tip is clean of the pink, is the desired crescent shape, and is pure white. This scraping procedure eliminates the need for filing or sanding or both. This also is a delicate task and must be done quickly without searching for necessary implements. The need to do this is so that the white tip does not become clouding in appearance. It is desired that it be as pure white as is possible. [0017] After the pink-and-white fingernail process is complete, the customer may also desire a pattern, such as a flower design, on the pink section or the white section or both. Typically, a round-shaped nail cleaner is used for this purpose. This rounded end may be used to create various patterns and designs on the fingernail [such as, but not limited to, flower patterns, dots, hearts, raindrops, and the like], as desired, when first dipped in a suitable polish, a water-based paint, or other solution before dabbing onto the now-dried pink acrylic component or onto the now-dried white acrylic component or both. [0018] Consequently, to process the pink-and-white fingernail, the manicure specialist must have at hand, [1] a large nail brush to apply the pink and white acrylic, [2] a small nail brush to work the white acrylic/polish to the desired crescent-moon shape and to apply a clear glossy gel as a topcoat for a shiny finished look, [3] a nail scraper to remove any excess pink acrylic overlapping the white tip, [4] a nail cleaner to clean excess acrylic under the fingernail, and [5] a nail-design tip to apply design patterns as may be desired by the customer. With the need to work fast due to the fast-drying acrylics, and the requirement of four or more nail-care implements to perform four to five functions, one or more such nail-care implements may not be readily handy or found when precisely needed due to the speed in which the manicure specialist must operate. [0019] The device of my co-pending application, application Ser. No. 11/868,639, combines all these stand-alone prior art nail-care implements required in the pink-and-white fingernail process into a single device to thereby permit the user to be more effective and more efficient in the pink-and-white fingernail process. That single device eliminated the need to switch back and forth between the multiple nail-care implements or the need to locate a misplaced nail-care implement when precisely need. All these components in that single device also eliminated the frustration associated with the very possibility of misplacing one essential prior art nail-care implement and then searching for it or a suitable replacement while in the middle of a pink-and-white fingernail process. [0020] All the user needs to do with that device of my co-pending application is to rotate it from one desired component [large nail brush] to the next desire component [scraper/nail cleaner], or to remove another component [small nail brush] from the handle receptacle of the large nail brush. The pink-and-white fingernail process is simplified and expedited in the process. [0021] Additionally, with all these components incorporated into a single device renders the cost of manufacture and cost to purchase substantially less than the cost of buying several stand-alone prior art nail-care implements. Moreover, if a component is damaged, only that component need be replaced rather than the entire device. The disclosure of my co-pending application, application Ser. No. 11/868,639, is incorporated by reference into this present disclosure of my improved multi-function cosmetic device. [0022] This new and improved device: [0023] a. provides a greater locking capability between the two ends [a twist-lock option and a better friction-lock option]; [0024] b. provides an option for a single-end working component without a second end working component; [0025] c. gives the user an option to use just a single large brush with a cap at the end or just a single small brush with a cap on the end or a small brush with two inter-changeable working components on each end which are removable from each other; and [0026] d. with either option above, provides a stackability feature over which more than one working component can be stacked on a previously stacked component. [0027] The foregoing has outlined some of the more pertinent objects of the improved manicuring device as set forth in this disclosure. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the improved manicuring device. Many other beneficial results can be attained by applying the disclosed improved manicuring device in a different manner or by modifying the improved manicuring device within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the improved manicuring device as set forth in this disclosure may be had by referring to the summary of the improved manicuring device and the detailed description of the preferred embodiment in addition to the scope of the improved manicuring device defined by the claims taken in conjunction with the accompanying drawings. SUMMARY [0028] The above-noted problems, among others, are overcome by the improved cosmetic and manicuring device as set forth in this disclosure. Briefly stated, the improved cosmetic and manicuring device contemplates an improved multi-function cosmetic device having a first and a second component, each removable from one another. The second component has a first section and a second section each of which are also removable from one another. The front of the first component and the fronts of the first and second sections of the second component are working components, such as, but are not limited to, fingernail brushes, fingernail scrapers/cleaners, and fingernail design tips. [0029] A connecting means for removably connecting the first component to the second component, and for removably connecting the first section to and from the second section of the second component are of a twist-locking mechanism or a friction-locking mechanism. The twist-lock has a shaft extending outward of both components or sections with a half-moon top and a three-quarter moon slot between the top and the shaft. The tops of each twist-lock align with each other, are pushed together, and rotated approximately one-quarter turn to seat the tops of each into the slots of the other thereby locking the two together. The friction-lock has a skirt extending outward from either component and section, with a plurality of slits cut through the skirt, and are insertable into a cooperating receiving chamber of the other component or section. [0030] Individual and independent couplers may have a friction-lock on one side and a twist-lock on the other side which accept any cooperating connector. The independent couplers also may have a friction-lock on each side or a twist-lock on each side which accept any cooperating connector. [0031] Additional independent stackable components, each having a similar working component at their respective front ends, are removably stackable onto the fronts of either first component or the fronts of the first and second sections of the second component and are removably stackable onto each other. [0032] The foregoing has outlined the more pertinent and important features of the improved cosmetic and manicuring device as set forth in this disclosure in order that the detailed description that follows may be better understood so the present contributions to the art may be more fully appreciated. Additional features of the improved cosmetic and manicuring device will be described hereinafter which form the subject of the claims. [0033] It should be appreciated by those skilled in the art that the conception and the disclosed specific embodiment may be readily utilized as a basis for modifying or designing other structures and methods for carrying out the same purposes of the improved cosmetic and manicuring device as set forth in this disclosure. It also should be realized by those skilled in the art that such equivalent constructions and methods do not depart from the spirit and scope of the improved cosmetic and manicuring device as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0034] For a fuller understanding of the nature and objects of the improved cosmetic and manicuring device as set forth in this disclosure, reference should be had to the following detailed description taken in conjunction with the accompanying drawings in which: [0035] FIG. 1 is a detailed front elevation view of a fingernail. [0036] FIG. 2 is a side elevation view of a fingernail. [0037] FIG. 3 is a side elevation view of a fingernail with a nail tip attached. [0038] FIG. 4 is a front elevation view of a fingernail with a nail tip attached. [0039] FIG. 5 is an exploded perspective view of the device of the present disclosure illustrating a large brush on one end the either a cap or a dual-component small brush on the other end. [0040] FIG. 6 is an exploded perspective view of the device of the present disclosure illustrating a twist-lock fit of a dual-component. [0041] FIG. 7 is an exploded view of the device illustrating a combination twist-lock and skirt-type friction fit coupler and the stackability feature of the device. [0042] FIG. 8 is a detailed partial view in cross-section illustrating more than one working component stacked upon another working component. [0043] FIG. 9 is a detailed view of the working components of FIG. 8 unstacked from each other. [0044] FIG. 10 is a detailed view of a connector component having a skirt-type friction-lock on both ends. [0045] FIG. 11 is a detailed view of a connector component having a twist-lock on both ends. [0046] FIGS. 12-15 are detailed views of the twist-lock component. DETAILED DESCRIPTION [0047] Referring now to the drawings in detail as to FIGS. 1 through 7 , and in particular to reference character 10 of FIG. 5 , generally designates an improved multi-function cosmetic device constructed in accordance with the preferred embodiments thereof. [0048] FIGS. 1 through 4 are illustrative of a human finger 70 having a cuticle 71 and fingernail 60 . The fingernail 60 consists of, from the cuticle 71 up, the lunula 61 [moon-like white section], the nail body 62 [pinkish section], and the free edge 63 [the basically white-like in color distal end grown out from the distal end of the finger 70 ]. [0049] As discussed in the background, the pink-and-white process for fingernails is time-consuming, detailed work, and requires several different nail-care implements. Each such nail-care implement is a stand-alone nail-care implements which generally needs to be alternated in the pink-and-white process. Consequently, the manicure specialist will lay down one nail-care implement and pick up another, and do this repeatedly during the course of the process. The pink-and-white process requires speed, in that the acrylics are extremely fast-drying, and detail or else the user must start over. Mis-placing a nail-care implement when needed most is a prelude disaster and generally will require the manicure specialist to start over. [0050] The improved multi-function cosmetic and manicure device of the present disclosure has a first component 20 with a front 21 and a back 22 and here illustrating a brush 25 at the front 21 and a removably attachable second component which could be a cap 40 having a front 41 and a back 42 wherein the back 42 inserts into the first component; or it could be a working component [dual or single], as illustrated by reference character 50 , which is also insertable from either end into the first component 20 . [0051] As illustrated in FIGS. 5 and 6 , the front 21 of the first component 20 is a working component; i.e., comprised of a brush 25 , generally for fingernails, or such working component could be, though not limited to, a scraper 29 , or even a design tip 27 as illustrated in FIGS. 7 through 9 . [0052] The back 22 of the first component 20 has a receiving chamber 24 which has a width-A 1 . Where the second component is a cap 40 , the back end 42 of the cap 40 has a width-A 2 wherein width-A 2 is slightly less than width-A 1 . The back end 42 also has one or more nubs or detents 36 thereon as illustrated in FIG. 5 . Such configuration permits the insertion of the back end 42 into the receiving chamber 24 so that the back end 42 translates into the receiving chamber 24 and the protruding nubs 36 exert outward force on the inner walls of the receiving chamber 24 to thereby securely retain the cap 40 to the first component 20 . [0053] FIGS. 5 through 9 are illustrative of a preferred embodiment of a second component 50 , insertable into the first component 20 wherein the second component 50 is comprised of a working component on one or both sections wherein the sections are removably connectable from and from one another. [0054] Reference character 50 of FIG. 50 illustrates the second component 50 having a brush 25 at the outer end of the first section 51 and a design tip 27 at the outer end of the second section 52 . The two sections 51 , 52 are connectable to one another by a combination coupler 380 . [0055] The first section 51 is shown with a twist-lock type connector component 81 at its back end. Reference is made to FIGS. 12 through 15 for the details associated with the twist-lock type connector component 81 . The top 84 of this twist-lock type connector component 81 is approximately half-moon shaped. Between the top 84 and the shaft 87 is an approximately three-quarter-moon slot 86 . The half-moon top 84 has a thickness-B 1 and the three-quarter-moon slot 86 has a width-B 2 wherein width-B 2 is slightly greater than thickness-B 1 to permit the top 84 of one twist-lock connector component 81 to engage and enter the slot 86 of any cooperating twist-lock connector component 81 . A rim or neck 26 surrounds the twist-lock connector component 81 up to the half-moon top to a point approximately one-half of its thickness; about one-half the distance of thickness-B 1 . As such, a recess is defined with the rim 26 by the half-moon top 84 and the three-quarter moon slot 86 . The outer perimeter of the rim 26 has a width-A 2 rendering it insertable into the receiving chamber 24 of the first component 20 . The rim 26 will also have one or more nubs 36 thereon for a secure fit. [0056] A similarly configured cooperating twist-lock connector component 81 is on one end of the combination coupler 380 . In operation, the respective half-moon tops 84 are to be aligned with one another such that the combination coupler 380 may be pushed in the direction of Arrow-X toward and into the recess of the cooperating twist-lock component connector 81 of the first section 51 . Once so inserted, the rim 26 or each respective twist-lock component connector 81 encircles the two opposing twist-lock connector components 81 and the combination coupler 380 is then rotated in the direction of Arrow-Y, approximately one-quarter turn, causing the top 84 of the combination coupler 380 to engage the slot 86 of the first section and the top 84 of the first section to engage the slot 86 of the combination coupler 380 . [0057] Once so engaged the first section and the combination coupler 380 are secured to one another. As attached the outer ends of each respective rim 26 approximately abuts its counterpart rim 26 . [0058] On the opposite end of the combination coupler 380 is a skirt-type friction-lock connector component 91 . In the approximate center of the combination coupler 380 is a collar 82 having a width-A 3 wherein width-A 3 is greater than width-A 1 . Extending away from the collar 82 in the direction of the twist-lock component 91 is a rim 26 without a recess and with nubs 36 around the rim 26 . Extending away from the collar 82 in the direction of the friction-lock connector component 91 is a collar shaft 23 having a width-A 2 and nubs 36 thereon. This configuration permits insertion of the rim 26 of either side of the combination coupler 380 into the receiving chamber 24 of the first component 20 such that said insertion will terminate at the collar 82 . The nubs 36 provide securing outward force on the inner wall of the receiving chamber 24 . [0059] Extending farther out from the collar shaft 23 on this combination coupler 380 is the friction-lock connector component 91 . A plurality of slits 96 are cut through the skirt 94 and are approximately perpendicular to the collar 82 . The outer perimeter of the skirt 94 has a width-A 7 wherein width-A 7 is equal to or greater than width-A 5 . This permits the friction-lock component 91 to compress as necessary as it is being inserted into the receiving chamber 34 of the second section 52 and to exert outward pressure against the inner wall of that receiving chamber 34 , which has a width-A 5 , thereby securing the combination coupler 380 to the second section 52 . [0060] The first section 51 also has a collar 82 forward of the rim 26 wherein said collar 82 has a width-A 3 followed a collar shaft 23 with one or more nubs 36 thereon. The collar shaft 23 has a width-A 2 which facilitates insertion into the receiving chamber 24 of the first component 20 [as described above]. Forward of the collar shaft 23 is a shaft 37 having a width-A 6 wherein width-A 6 is less than width-A 2 and less than width-A 5 thereby making it insertable into a receiving chamber 34 as described above. [0061] An additional unique feature of this improved multi-function cosmetic device is its stackability feature and the stacking extensions 28 A, B, C. FIG. 5 illustrates a stacking extension 28 A having a design tip 27 at its front and a receiving chamber 34 at its back. As alluded to above, the cavity in the receiving chamber 34 has a width-A 5 which is slightly greater than width-A 6 and may be equal to or less than width-A 7 . As described below, this permits this stackable extension 28 A, or any similarly configured extension, to stack onto the shaft 37 of a preceding extension or onto the friction-fit component 91 due to the ability of the friction-fit component 91 to flex inward [or outward]. [0062] Rearward of the design tip 27 is a shaft 37 having a width-A 6 and one or more nubs 36 thereon. The shaft 37 terminates at the ledge 38 wherein the ledge has a width-A 4 . The shaft 37 or this extension 28 A, and all similarly configured extensions 28 B, 28 C is removably insertable into a receiving chamber 34 of any preceding extension 28 A, 28 B, 28 C. FIGS. 5 through 9 are illustrative. [0063] FIG. 9 also illustrates that a cap 16 having an inner chamber with a width-A 5 or width-A 1 . With width-A 5 , the cap 16 may be inserted over onto a shaft 37 of an extension 28 C or any extension 28 A, 28 B. With width-A 1 , the cap 16 may be inserted over the first section 51 over the collar shaft 23 or any similarly constructed section or extensions. [0064] As illustrated in various figures, a working component may comprise a scraper 29 extending beyond the shaft 37 [stackable extension 28 B], and may also include but not be limited to, a brush 25 [stackable extension 28 C] or a design tip 27 [stackable extension 28 A]. [0065] Though the various locking components have been described as being in combination with another different locking component, they may be in combination with one another as illustrated in FIGS. 10 and 11 . The twist-lock component 81 coupler may have the twist-lock component on each end, as illustrated by reference character 280 , FIG. 11 . The friction-lock component 91 coupler may have the friction-lock component on each end, as illustrated by reference character 180 , FIG. 10 . The structures and widths referenced in and for FIGS. 10 and 11 are as described above. [0066] FIGS. 12 through 15 are illustrative of the details associated with the twist-lock 81 component. An additional feature to the component is the beveled edge 85 from the top 84 beveling toward the shaft 87 and the well 83 on the floor 89 of this component. The well 83 may be used to apply a tacky substance or more adhesive substance to thereby strengthen the fit when one twist-lock component 81 is inserted into another twist-lock component 81 . [0067] This improved multi-function cosmetic device accords a user greater flexibility of choice in selecting which configuration is best-suited for that user's purpose and greater flexibility and ease in modifying the working components on the device as best-suited for the particular operation. The stackability feature allows easily changing out the working ends. The dual working ends provides ease of switching which working end is desired at the moment. The locking features, twist-lock and friction-lock, make for a sturdy two-working component device; i.e., a working component on both ends of the device each of which are held steadfast in place. [0068] The present disclosure includes that contained in the present claims as well as that of the foregoing description. Although this improved cosmetic and manicuring device has been described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms has been made only by way of example and numerous changes in the details of construction and combination and arrangement of parts and method steps may be resorted to without departing from the spirit and scope of the improved cosmetic and manicuring device as set forth in this disclosure. Accordingly, the scope of the improved cosmetic and manicuring device should be determined not by the embodiment]s[ illustrated, but by the appended claims and their legal equivalents. [0069] Applicant has attempted to disclose all the embodiment[s] of the improved cosmetic and manicuring device that could be reasonably foreseen. It must be understood, however, that there may be unforeseeable insubstantial modifications to improved cosmetic and manicuring device as set forth in this disclosure that remain as equivalents and thereby falling within the scope of the improved cosmetic and manicuring device.

A multi-function cosmetic device having a first and a second component, each removable from one another wherein the second component has a first section and a second section each of which are removable from one another. The front of the first component and the fronts of the first and second sections are working components, such as, but are not limited to, fingernail brushes, fingernail scrapers/cleaners, fingernail design tips, and make-up brushes. Additional independent stackable components, each having a similar working component at their respective front ends, are removably stackable onto the fronts of either first component or the fronts of the first and second sections of the second component and are removably stackable onto each other.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is the U.S. National Stage of International Application No. PCT/EP2010/002427, filed Apr. 21, 2010, which designated the United States and has been published as International Publication No. WO 2010/130329 and which claims the priority of German Patent Application, Serial No. 10 2009 021 093.8, filed May 13, 2009, pursuant to 35 U.S.C. 119(a)-(d). BACKGROUND OF THE INVENTION The invention relates to a wheel suspension of a motor vehicle. In so-called active steering systems, especially for the rear axle of vehicles, the wheel camber or the wheel toe can be adjusted via an actuator so that handling of the motor vehicle can be influenced by controlling the actuator. DE 10 2004 049 296 A1 discloses a generic wheel suspension for a motor vehicle. It includes a hub unit which rotatably supports the vehicle wheel, and an axle-side guide part, with rotary parts being disposed between the hub unit and the guide part. The rotary part facing the hub unit is a cylindrical adjusting ring having cylindrical inner and outer effective areas which interact with corresponding effective areas of the other rotary part and the hub unit. The rotation axes of both rotary parts are aligned at a slant in relation to one another. When the two rotary parts are rotated, the wheel toe or the wheel camber can be adjusted. Both rotary parts can be rotated in any relation to one another by servo drives. The desired toe-in/camber adjustment can be established in dependence on the combination of the rotation angles. In the extreme case, the resultant diffraction angle may be in the order of several angle degrees. This means that the carrier part can be positioned at a slant at an angle of several angle degrees in relation to the guide part which is mounted with further suspension arms to the vehicle body. SUMMARY OF THE INVENTION The invention is based on the object to provide a wheel suspension which allows a reliable support of encountered radial forces and axial forces. The object is solved by a wheel suspension for a motor vehicle, including a wheel-side carrier part rotatably supporting a vehicle wheel, and an axle-side wide part between which rotary parts are arranged and rotatable in relation to one another, with the guide part, the rotary parts and/or the carrier part interacting with facina first and second effective areas, wherein the facing effective areas between the guide part, the rotary part and/or the carrier part of the wheel suspension are not configured cylindrically but a first effective area may radially delimit a conical or spherical hollow profile in which the second facing effective area is able to at least substantially engage formfittingly. The inventive idea may conceivably include different variants of the two facing effective areas: For example, both facing effective areas may have conical configuration, or a first one of the effective areas may be configured as spherical cup whereas the second effective area may have a corresponding spherical configuration to engage this spherical cup. As an alternative, the first effective area can be conical whereas the second effective area is a surface in the shape of a spherical disk to thereby establish a conical socket/spherical disk bearing. According to a preferred embodiment, the two rotary parts placed between guide part and carrier part may form an actuator for adjusting a toe angle and/or camber angle. The facing effective areas can hereby be dimensioned between the two rotary parts in such a way as to slantingly position the rotation axis of the one rotary part in relation to the rotation axis of the other rotary part by an inclination angle. In accordance with a variant, the facing effective areas can contact one another directly or through intervention of a friction-reducing coating so as to provide overall a cost-efficient and durable slide bearing between both effective areas. As an alternative, the facing effective areas can be connected to one another via a roller bearing. This may be a tapered roller bearing when the effective areas have a conical configuration. According to the invention, three bearing points are established between the four-part wheel carrier comprised of carrier part, the two rotary parts and the guide part. In order to reliably absorb axial and radial forces, it is of advantage to configure each of the bearing points with tapered roller bearings. As described above, the second rotary part has an effective area which faces the first rotary part and an effective area which faces the guide part. For a particularly compact construction that is stable in axial direction, these two effective areas may be expanded in opposite directions to one another on the second rotary part. As described above, the first rotary part has in contrast thereto an effective area which faces the carrier part and an effective area which faces the second rotary part, with both effective areas being expanded in a same direction in a conical or spherical manner. In light of this background, the second rotary part may include in axial direction on both sides a conical or spherical hollow profile, respectively, for engagement of the first rotary part on one hand and also the guide part on the other hand. The carrier part can be further arranged with its effective area radially inwards of the first rotary part for better use of installation space. The wheel-side carrier part and the axle-side guide part can be fixed by a restraining means. In particular, the restraining means can apply a biasing force to maintain the guide and carrier parts under tension in the axial direction. As a result of such a securement or bracing of the carrier and guide parts, the bearing points can be exposed to loads, in particular axial compressive forces and radial forces, while axial pulling forces may be absorbed by the restraining means itself. With regard to assembly, it is beneficial to interconnect the four parts of the wheel carrier, comprised of carrier part, the rotary parts and the guide part, in an assembly direction roughly by a plug-in connection, without the need for an undercutting construction to axially fix the parts. The assembly may be implemented by simply plugging the parts together. For structural reasons, it is furthermore preferred when the restraining means connects the guide part and the carrier part with one another, wherein the restraining means can be arranged radially outside the rotary parts. The restraining means may at the same time act as a coupling between the carrier part and the guide part. The coupling can again transmit as a torque bridge a torque, such as a braking torque, from the carrier part onto the guide part and thus to the vehicle body. The restraining means may hereby be configured preferably as cardan joint or metal bellows. BRIEF DESCRIPTION OF THE DRAWING The invention will now be described with reference to several exemplified embodiments. It is shown in: FIG. 1 a basic representation of the device for adjusting toe and camber angles of a wheel suspension for motor vehicles with a multi-part wheel carrier; FIG. 2 a concrete implementation of the device according to FIG. 1 , having a carrier part which carries a wheel, a guide part which is articulated on wheel guide elements of the wheel suspension, and two pivotable rotary parts which can be adjusted by electric servomotors; FIG. 3 the device according to FIG. 2 by way of an enlarged illustration of the arrangement and pivotal support of the rotary parts and the carrier and guide parts; FIG. 4 a greatly simplified view of the device for illustration of the adjustment mechanism; and FIGS. 5 a to 5 c various variants of the effective areas between the two rotary parts. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS For a theoretical explanation of the invention, FIG. 1 shows a rough basic representation of a wheel carrier 10 of a wheel suspension for motor vehicles, which carrier is subdivided for adjustment of the camber and/or toe of the vehicle wheel as follows: The wheel carrier 10 has a carrier part 12 in which the wheel and the brake element (brake disk, brake drum) of a service brake of the motor vehicle is rotatably supported. It should be noted that any functional parts of the wheel suspension that have not been described can be of conventional structure. The wheel carrier 10 further includes a guide part 14 which interacts with the wheel suspension or optionally may form part of the wheel suspension. Two substantially rotation-symmetrical rotary parts 16 , 18 are provided as actuators between the carrier part 12 and the guide part 14 and are connected for rotation with the carrier part 12 and the guide part 14 , respectively, via respective rotation axes 20 , 22 . Both rotation axes 20 , 22 are oriented coaxially in the figures and extend in the wheel rotation axis. Whereas the contact surfaces of the rotary parts 16 , 18 directly adjacent to the carrier part 12 and the guide part 14 are configured rotation-symmetrically, the rotary parts 16 , 18 bear upon one another via slanted surfaces 16 b , 18 b in such a way that the rotary part 16 pivots about a rotation axis 24 which is inclined upwards in FIG. 1 . The rotation axis 24 is thus oriented, as shown, perpendicular to the slanted surfaces 16 b , 18 b and inclined at a defined angle x in relation to the rotation axis 22 . In FIG. 1 , the center axis 20 of the carrier part 12 is oriented in coaxial relation to the rotation axis 22 of the guide part 14 so that the vehicle wheel, held on the carrier part 12 , is set without camber and toe angles. FIG. 4 , which is being described further below, indicates in addition also the center axis 20 ′. The shown angular disposition of the center axis 20 ′ is established as the rotary parts 16 , 18 pivot about a rotation angle of 180°. Provided on the carrier part 12 and the guide part 13 are electric servomotors 26 , 28 , respectively, which are connected in driving relationship with the rotary parts 16 , 18 in the basic representation via toothed belts 30 . The rotary parts 16 , 18 can be rotated by the servomotors 26 , 28 in same direction or in opposite direction in both rotational directions so that the carrier part 12 executes a pivoting motion or a wobbling motion in order to accordingly change the toe angle and/or the camber angle of the wheel. FIGS. 2 and 3 show a longitudinal section of a concrete embodiment of the wheel carrier 10 along the rotation axis 22 of the wheel of the wheel suspension. As described above, the wheel carrier 10 is comprised of the guide part 14 which is articulated to wheel guide elements such as suspension arms etc., the carrier part 12 which supports the wheel, and the rotation-symmetrical rotary parts 16 , 18 . The guide part 14 has a support flange 34 which supports a radially inwardly arranged bearing ring 36 . According to FIG. 3 , the conical effective area 36 a of the bearing ring 36 faces the conical effective area 18 a of the radially outwardly arranged rotary part 18 . The bearing ring 36 forms via bearing rollers 38 with the radially outwardly arranged rotary part 18 a first tapered roller bearing which is defined by a rotation axis in coincidence with the rotation axis 22 . The rotary part 18 has an outer circumference provided with a gear rim 18 c which interacts in driving relationship with an invisible drive gear of the electric servomotor 28 . The servomotor 28 is also mounted to the support flange 34 of the guide part 14 . According to FIG. 3 , the carrier part 12 has a radially aligned flange portion 40 and an axially extending hub portion 42 . The hub portion 42 extends radially within the two rotary parts 16 , 18 up to a level with the bearing ring 36 of the support flange 34 . Provided within the flange portion 40 is a wheel bearing 44 as pivot bearing for a wheel flange 46 which has a hub portion 48 which projects likewise axially to the hub portion 42 also roughly up to the bearing ring 36 . The wheel or the wheel rim 32 and the brake disk 52 of a disk brake are fastened to the wheel flange 46 by wheel bolts 50 (shown also partially). The caliper of the disk brake is fastened to the flange portion 40 of the carrier part 12 in a manner which is not apparent. Furthermore, the rotary part 16 is rotatably supported on the hub portion 42 via an inner bearing ring 54 and a tapered roller bearing 56 , with the rotation axis of the hub portion also coinciding with the wheel rotation axis 22 . The inner bearing ring 54 and the radially outer rotary part 16 have facing conical effective areas 54 a and 16 a between which the tapered roller bearing 56 is provided. The rotary part 16 is further rotatably supported in the rotary part 18 via a third tapered roller bearing 58 with bearing rollers. The relevant conical effective areas 16 b , 18 b are hereby slantingly configured in relation to the rotation axis 22 so that a rotation causes adjustment of the camber angle and/or toe angle of the wheel from the neutral position in a range of about 5°. According to FIG. 3 , the rotary part 16 engages into an axial groove 40 a of the flange portion 40 and supports an outer gear rim 16 c which is connected in driving relationship with the servomotor 26 via a hidden drive gear and through a recess in the flange portion 40 . The servomotor 26 is respectively fastened to the flange portion 40 of the carrier part 12 . The wheel flange 46 is operated via a cardan shaft 60 , shown only in part by way of its bell-shaped joint housing 62 and the sleeve-shaped driving journal 64 for the sake of simplicity. The driving journal 64 is inserted via a spline 64 a into the hub portion 48 of the wheel flange 46 and tightened by a locking bolt 66 with a locking sleeve 68 against the wheel flange 46 . A distance sleeve 69 is supported between a ring shoulder of the bell-shaped joint housing 62 and the wheel bearing 44 and arranged in coaxial relationship to and in radial direction between the hub portions 42 , 48 of the carrier part 12 and the wheel flange 46 . The locking bolt 66 thus braces the assembly comprised of locking sleeve 68 , wheel flange 46 , wheel bearing 44 , distance sleeve 69 , and cardan shaft 60 . According to FIGS. 2 and 3 , a cardan ring 72 is provided radially outside the rotary parts 16 , 18 as restraint against rotation between the guide part 14 and the carrier part 12 and is guided on the flange portion 40 of the carrier part 12 in circumferential direction in a formfitting manner via, for example, axial catches which project into the cardan ring 72 . The cardan ring permits only angular deflections but no relative rotation. The device for adjustment of the wheel camber and/or toe, as described above, is sealed radially to the outside against environmental impacts such as moisture and dirt by a rubber-elastic bellows 74 (cf. FIG. 2 ). The bellows 74 is respectively fastened to ring-shaped projections 40 a , 34 a of the flange portion 40 of the carrier part 12 and the support flange 34 of the guide part 14 . As an alternative, as shown in FIG. 4 , the bellows 74 may be configured as thin-walled metallic bellows which is sufficiently torsionally rigid to provide restraint against rotation but yet is sufficiently flexible as to lastingly accommodate the mentioned adjustment angles while sealing the radially inwardly arranged functional parts. The described cardan ring 72 can then be omitted. A radial inner sealing of the rotary parts 16 , 18 and their roller bearings etc. is provided between the bearing ring 36 on the support plate 34 of the guide part 14 and the hub portion 42 of the carrier part 12 in the region of the bell-shaped joint housing 62 of the cardan shaft 60 . It should be noted in this context that the carrier part 12 executes a wobbling motion with a pivot center in the middle of the cardan joint at M ( FIG. 4 ) so that sufficient clearance should be provided at the annular gap between the bell-shaped joint housing 62 and the bearing ring 36 . A sleeve-shaped sealing ring 76 is supported on the hub portion 42 for axial displacement to ensure reliable sealing and has on its end face a spherical portion 76 a which interacts with a concavely shaped recess 36 b in the bearing ring 36 . FIG. 4 shows in a greatly simplified way the adjustment mechanism of the wheel suspension according to the invention. Therefore, the servomotors 26 , 28 within the metal bellows 74 are operatively connected with the rotary parts 16 , 18 which are indicated by the arrows. As already described with reference to FIG. 3 , the rotary part 18 has two effective areas 18 a and 18 b . The effective areas 18 a , 18 b are expanded conically in mutually opposite directions. The effective areas 18 b and 16 b of both rotary parts 16 , 18 , which areas are relevant for camber and toe adjustment are inclined upwards at a slant to the rotation axis 22 by a cone angle (y+x) and (y−x), respectively. The conical effective areas 54 a , 16 a between the bearing ring 54 and the rotary part 16 are hereby nested within one another in axial direction. FIGS. 5 a to 5 c schematically show further variants of the invention. The arrangement shown in FIG. 5 a corresponds in its basic structure and mode of operation to the preceding devices. The difference to the preceding devices resides in FIG. 5 a in the provision between the rotary parts 16 , 18 of a slide bearing in which the conical effective areas 16 b , 18 b are in direct contact. The rotary parts 16 , 18 are moreover in rotating connection with the carrier part 12 and the guide part 14 via not shown radial and axial bearings. In contrast to FIG. 5 a , the slide bearings illustrated in FIGS. 5 b and 5 c between the rotary parts 16 , 18 are not realized using corresponding conical effective areas 16 b , 18 b . Rather, the effective area 16 b of the rotary part 16 is configured in FIG. 5 b roughly in the shape of a sphere and in sliding contact with an effective area 18 b of the rotary part 18 of concave shape. In contrast thereto, the effective area 16 b of the rotary part 16 in FIG. 5 c is configured as a surface in the shape of a spherical disk and projects into an effective area 18 b configured as a surface in the shape of a conical socket.

The invention relates to a wheel suspension for a motor vehicle, comprising a wheel-side carrier part ( 12 ) holding a vehicle wheel ( 1 ) in a rotatable manner, and an axle-side guiding part ( 14 ) between which mutually rotating rotary parts ( 16, 18 ) are arranged. The guiding part ( 14 ), the rotary parts ( 16, 18 ) and/or the carrier part ( 12 ) interact with first and second effective areas ( 18 a, 36 a; 18 b, 16 b; 16 a, 54 a ) facing each other. According to the invention, the first effective area radially defines a conical or spherical hollow profile into which the corresponding second effective area protrudes in an essentially form-fitting manner.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional Patent Application No. 61/709,091. This application is a continuation of U.S. patent application Ser. No. 14/044,136. The contents of both applications are hereby incorporated by reference in their entirety. BACKGROUND [0002] The use of autonomous or unmanned vehicles is growing. Unmanned vehicles may be suitable for a variety of industries including construction, manufacturing, and military. While there are many advantages associated with the use of autonomous vehicles, there are also several issues. [0003] On such issue is safety. For example, how do we ensure that unmanned vehicles can be stopped should they become unresponsive due to a software malfunction, or when a remote operator becomes incapacitated or otherwise loses control of the vehicle? Another issue is interoperability. Currently there exist many proprietary systems for unmanned vehicles, making it difficult to design systems or applications that will work across a variety of vehicle systems and types. SUMMARY [0004] An open architecture control system is provided that may be used for remote and semi-autonomous operation of commercial off the shelf (COTS) and custom robotic systems, platforms, and vehicles to enable safer neutralization of explosive hazards and other services. In order to effectively deal with rapidly evolving threats and highly variable operational environments, the control system is built using an open architecture and includes a high level of interoperability. The control system interfaces with a large range of robotic systems and vehicles, autonomy software packages, perception systems, and manipulation peripherals to enable prosecution of complex missions effectively. Because the control system is open and does not constrain the end user to a single robotics system, mobile platform, or peripheral hardware and software, the control system may be used to assist with a multitude of missions beyond explosive hazard detection and clearance. [0005] In an implementation, a method may include: receiving a current location of an operator at an instrument control system of an unmanned vehicle; determining a leading distance of the unmanned vehicle by the instrument control system; determining a current location of the unmanned vehicle by the instrument control system; determining if a difference between the current location of the operator and the current location of the unmanned vehicle is less than the leading distance; and if so, increasing the speed of the unmanned vehicle by the instrument control system. [0006] In some implementations, the method may further include: determining if a difference between the current location of the operator and the current location of the unmanned vehicle is greater than the leading distance; and if so, decreasing the speed of the unmanned vehicle by the instrument control system. The method may further include that the current location of the operator is received from a hand held controller, and that the leading distance is randomly generated. [0007] In an implementation, a system for halting the operation of machinery may include: at least one e-stop controller comprising a first radio; and at least one e-stop comprising: a second radio; a software based failsafe; and a hardware based failsafe, wherein the hardware based failsafe is adapted to: monitor a wireless connection between the first radio and the second radio; determine if the wireless connection has been severed; and if so, halt machinery associated with the e-stop; and wherein the software based failsafe is adapted to: receive a first signal from the e-stop controller via the second radio; and determine whether to halt the machinery associated with the e-stop based on received first signal. [0008] In some implementations, the system may further include that the first signal is a heartbeat signal, and the software based failsafe may determine not to halt the machinery associated with the e-stop based on the heartbeat signal. The first signal may be a stop signal, and the software based failsafe may determine to halt the machinery associated with the e-stop based on the stop signal. The system may further include that the e-stop controller is further adapted to: determine whether to halt the machinery associated with the e-stop; and if so, sever the wireless connection between the first radio and the second radio. Severing the wireless connection may include turning off the first radio. Determining whether to halt the machinery associated with the e-stop may include determining that a second signal has not been received from the e-stop for more than a threshold amount of time. The second signal may be a heartbeat signal. [0009] In some implementations, the system may further include a plurality of e-stops and e-stop controllers, wherein the plurality of e-stops and e-stop controllers form a mesh network. The e-stop controller may be automatically associated with the e-stop based on a distance between the e-stop and the e-stop controller. The e-stop may include a first location determiner and the e-stop controller may include a second location determiner, and further wherein: the e-stop is adapted to determine a first location of the e-stop using the first location determiner and send the determined first location to the e-stop controller; and the e-stop controller is adapted to determine a second location of the e-stop controller using the second location determiner, determine if a distance between the first and second locations exceeds a threshold, and if so, determine to halt the machinery associated with the e-stop. Determining to halt the machinery associated with the e-stop may include one of sending a stop signal to the e-stop and turning off the first radio. The machinery may be an unmanned vehicle. [0010] In an implementation, a system for controlling unmanned vehicles may include: a vehicle integrated control system that is non-destructively integrated into the unmanned vehicle; and an operation control unit that generates one or more instructions and provides the generated one or more instructions to the vehicle integrated control unit, wherein the vehicle integrated control unit is adapted to receive the generated one or more instructions, and in response to the generated one or more instructions, control the operation of the unmanned vehicle, and further wherein the operation control unit is adapted to receive one or more of sensor data and location data from the vehicle integrated control unit, and to make the one or more of sensor data and location data available to one or more devices over a network. [0011] In an implementation, the system may further include that the devices are one or more of smart phones, laptops, or tablets. The operation control unit may include a Hand Held Controller and a Remote Viewing Sensor. [0012] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS [0013] The foregoing summary, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the embodiments, there is shown in the drawings example constructions of the embodiments; however, the embodiments are not limited to the specific methods and instrumentalities disclosed. In the drawings: [0014] FIG. 1 is a high level illustration of the OIP; [0015] FIG. 2 is a more detailed illustration of the OIP; [0016] FIG. 3 is an illustration of a vehicle control scenario using the OIP; [0017] FIG. 4 is an illustration of an example VSC; [0018] FIG. 5 is an illustration of an example HHC; [0019] FIG. 6 is an illustration of an example e-stop; [0020] FIG. 7 is an illustration of an example mesh network formed by e-stops and e-stop controllers; [0021] FIG. 8 is an illustration of an example method for increasing or decreasing a speed of a vehicle based on a leading distance; and [0022] FIG. 9 is an illustration of an example computing environment where aspects of the invention may be implemented. DETAILED DESCRIPTION [0023] FIG. 1 is a high level illustration of the Open Integration Platform (OIP) 100 . The OIP 100 is a control system for unmanned vehicles that translates user commands into manipulations or movements of the unmanned vehicle and provides for failsafe integration of third-party software, sensors, and actuation peripherals through an application programming interface (API). The OIP 100 may be configured to communicate with many robotic systems and vehicle command protocols and is portable across platforms in alternate operational scenarios. [0024] The OIP 100 may be designed to allow for easy integration with respect to one or more components through the API. Examples of such components are illustrated in FIG. 1 , and include autonomy software component 110 , perception component 120 , unmanned system component 130 , and manipulation components 140 . Other components may be supported. [0025] As will be described further below, the OIP 100 may further include one or more built-in or base features. One example of such a feature is the ability to interface and control a variety of vehicles. The OIP 100 may support a variety of vehicle control interfaces including Drive-by-wire, for example. Other vehicle control interfaces may be supported. The vehicle control commands and protocols used for a variety of vehicle types may be abstracted by the API into a single vehicle control library of functions, allowing users and programmers to create a single custom software component that may be used to control a variety of vehicle types using the API. The OIP 100 may similarly provide a single library of functions that may be used to control and interact with a variety of sensors and peripheral devices. [0026] Another example of an integrated feature is safety features. The safety features may be integrated into the OIP and kept separate from the other components of the OIP such that one or more of the autonomy software components 110 , unmanned system components 130 , perception components 120 , and manipulation components 140 can be changed by users without compromising the safety of the system as a whole. Further, such built in safety features allow users to create their own components for the OIP 100 using the API without having to consider how to implement safety features, or worrying about interfering with existing safety features. [0027] Any unmanned system developed using the OIP 100 as the integration hub may achieve the following advantages when compared with existing systems: [0028] Flexibility: The flexible API provided by the OIP 100 allows for a wide variety of components to be easily added or removed from any unmanned system that uses the OIP 100 . For example, users may add or remove components from the unmanned system as threats, mission needs, technologies, or budgets change. The open system of the OIP 100 ensures that the user can use a range of sensors and/or software components from a wide range of providers in their unmanned system, not just those provided by the original manufacturer of the unmanned system. [0029] Safety: By separating the safety features from the computation engine, any unmanned system built using the OIP 100 is assured a high level of safety. Furthermore, an open system built on OIP 100 may allow the components to be changed or modified without affecting the safety features of the system. [0030] Speed: Any unmanned vehicle built using the OIP 100 includes locked down protocols for low-level critical commands and safety supervision. Because these crucial elements of the system remain unchanged, all other elements of the system can be changed much faster than if the core elements had to be redesigned and integrated. [0031] Cost: Any customer or partner using the OIP 100 may be able to avoid substantial development costs for the base hardware and software that enables unmanned system integration. By relying on the OIP 100 for this core, a user would benefit from significant development and testing already completed for the OIP 100 . [0032] Innovation: Threats, tasks, technologies, and budgets change all the time in the world of unmanned systems, and increased innovation is required to confront such complexity. By utilizing an open system the OIP 100 , the user, customer, partner, and stakeholders can rely on a wealth of easily integrated existing technology to help solve problems and reduce complexity much faster, cheaper, and with higher quality than with closed systems. [0033] FIG. 2 is a more detailed illustration of the OIP 100 . In the example shown, the OIP 100 is broken down into two major subsystems: the Vehicle Integrated Control System (VICS) 200 and the Operator Control Unit (OCU) 250 . The VICS 200 may provide a non-destructive means through which one or more users may control a vehicle, may receive information about the vehicle, or may receive information from or control the operation of one or more peripheral devices 210 associated with the vehicle. The VICS 200 is non-destructive in that the vehicle may be operable by an in-vehicle driver even when the VICS 200 is attached or otherwise integrated into the vehicle, and when the VICS 200 is removed the functions of the vehicle are not impaired. [0034] The OCU 250 , on the other hand, may provide one or more customizable user interfaces through which one or more users may control the vehicle through the VICS 200 . The user interfaces may also be used to view data provided by the VICS 200 , or from the peripheral devices 210 associated with the VICS 200 . Other components and/or subsystems may be supported. The peripheral device devices 210 may include, but are not limited to, cameras, lights, weapons and other sensors. [0035] Together, the OCU 250 and the VICS 200 may be used to provide control over an unmanned vehicle, and may allow one or more operators of the unmanned vehicle to view and share data provided by one or more of the peripheral devices 210 , or from the vehicle itself. [0036] In some implementations, the VICS 200 may include a Vehicle Systems Controller (VSC) 230 . The VSC 230 may be adapted to non-destructably interface with a variety of vehicles using a variety of interfaces and/or control systems such as Drive-by-wire (J1939), Direct-drive electric motors (typically found in small robots), and Hydraulic or mechanical controls. Other systems or interfaces may be supported. The VSC 230 may receive a variety of diagnostic and status information from the vehicle including, but not limited to speed, temperature, oil pressure, fuel level, tire pressure, or any other information supplied by a vehicle in its normal operational state. The VSC 230 may also include one or more integrated sensors such as an accelerometer, a GPS or other location detection means, a magnetometer, a thermometer, and a barometer, for example. Other sensors may also be supported. The VCS 230 may be implemented using a general purpose computing device such as the computing system 900 described with respect to FIG. 9 . An exemplary VCS 230 is described further with respect to FIG. 4 . [0037] The VSC 230 may provide such information to one or more users associated with the OCU 250 through a wireless communication means that may be integrated into the VSC (i.e., Bluetooth, Wi-Fi, etc.). Alternatively, or additionally, the VSC may provide such information to one or more smart phones, tablets, or any other devices that are able to receive data via a wireless interface. [0038] For example, an owner of a fleet of construction vehicles may use the OCU 250 , or a smart phone associated with the owner, to query a VSC 230 connected to each of the vehicles in the fleet. Each VSC 230 may receive the query and may provide the status information associated with its associated vehicle to the OCU 250 . The owner may then use the status information assisted with each vehicle to determine which vehicles may require servicing. [0039] The VSC 230 may also control the operation of the vehicle through the one or more interfaces. For example, the VSC 230 may control the throttle, brakes, transmission, lights locks, or any other systems of a vehicle that may be controlled electronically through an interface. In some implementations, the VSC 230 may control the operation of the vehicle based on one or more signals received directly from the OCU 250 . In other implementations, the VSC 230 may control the operation of the vehicle based on one or more signals received directly from an Instrument Control System (ICS) 220 of the VICS 200 . [0040] In some implementations, the ICS 220 may include electrical and computer networking components and may interface with, and provide power to, a variety of components including lights, sensors, and cameras (i.e., the peripheral devices 210 ). The supported computer networking components may include Ethernet (powered or unpowered), USB, Bluetooth, eSATA, or any other type of networking or connecting means. The ICS 220 may receive power from a vehicle that the ICS 220 is mounted to, or may include its own power source such as a battery or one or more solar panels. In implementations where the ICS 220 receives power from the vehicle, the ICS 220 may include a fuse or other means to limit the amount of current that is drawn from the vehicle. The ICS 220 may be attached to a vehicle through a roof mount. Other vehicle locations or attachment means may be supported. [0041] The ICS 220 may further include a locating means 215 . The locating means 215 may determine the location of the ICS 200 , and therefore the location of the vehicle that the ICS 220 is attached to. Any one of a variety of technologies for determining locations such as GPS, and cellular triangulation may be used. [0042] The ICS 220 may a wireless interface 211 . The wireless interface 211 may include one or more radios and may be capable of receiving one or more control signals from the OCU 250 . The ICS 220 may further be capable of transmitting data from one or more of the peripheral devices 210 that are connected to the ICS through the one or more radios of the wireless interface 211 . The transmitted data may include output from the VSC 230 (e.g., information from and about the vehicle including speed, oil pressure, and other diagnostic information), signals from one or more of the peripheral devices 210 connected to the ICS 220 (e.g., video, audio, temperature, and other sensor data), and location information determined by the locating means 215 . In some implementations, both the control signals from the OCU 250 and the data signals from the ICS 220 may be received and provided by the same radio and/or frequencies of the wireless interface 211 . Alternatively, different radios and/or frequencies may be used for control signals and data signals. The ICS 220 may be implemented by a general purpose computing device such as the computing system 900 described with respect to FIG. 9 . [0043] The ICS 220 may further include one or more emergency stops (e-stops) 284 . When the ICS 220 receives a signal from the e-stop 284 , the ICS 220 may immediately disable the vehicle by sending the appropriate signal(s) to the VSC 230 . For example, in one implementation, the e-stop 284 may be highly visible button that is located inside and/or outside the vehicle. When the button is pushed, the ICS 220 may signal the VSC 230 to immediately stop the vehicle by applying the brakes and/or disengaging the throttle, for example. The particular steps or actions that occur upon engaging an e-stop 284 may be set by a user or administrator. The e-stops 284 may be both wired and wireless. In addition, in some implementations, the e-stop 284 signal may also be received directly by the VSC 230 providing additional safety protection and isolation from the various components of the ICS 220 . The e-stops 284 may be integrated into the OIP 100 , may be integrated into a third-party control and automation system, or may function as a stand-alone system as will be described further bellow. [0044] In some implementations, each e-stop 284 may be wirelessly controlled by one or more e-stop controllers 285 . When a user or operator of the e-stop controller 285 determines that the vehicle (or other stationary and non-stationary machinery such as factory equipment or farm equipment) should be stopped, the user may use the e-stop controller 285 to send a stop signal to the e-stop 284 corresponding to the vehicle. The e-stop 284 may then receive the stop signal, and may instruct the ICS 220 and/or VSC 230 to deactivate the vehicle. [0045] In some implementations, each e-stop 284 associated with a vehicle or VICS 200 may have its own associated e-stop controller 285 . Alternatively, one e-stop controller 285 may be associated with a variety of e-stops 284 within a selected range of the e-stop controller 285 , or are otherwise paired with the e-stop controller 285 . For example, a fleet of unmanned vehicles may be used on a construction site. Each vehicle may have a VICS 200 with an associated e-stop 284 . One or more foremen associated with the construction site may receive an e-stop controller 285 (a wireless dongle, for example) that is associated with or paired with the e-stops 284 of all the vehicles used on the construction site. If a foreman believes that an accident has occurred or that the safety of a worker is being compromised, the foreman may activate the e-stop controller 285 which will cause each associated e-stop 284 to disengage its associated vehicle. [0046] In another implementation, a user associated with an e-stop controller 285 may select the particular e-stop 284 that it would like to send a stop signal to. For example, the e-stop controller 285 may have a display that includes a list of the e-stops 284 and/or the vehicles or machinery associated with each e-stop 284 . A supervisor could use the display of the e-stop controller 285 to choose a specific vehicle or machinery that is behaving in an unsafe manner or may be malfunctioning, and may activate the e-stop 284 associated with that vehicle or machinery only. Such remote e-stop controller 285 functionality could be distributed to multiple individuals with safety responsibility, forming a distributed network of e-stops 284 and e-stop controllers 285 . Any individual in this network could choose any machine within the network that they would like to stop using the e-stop controller 285 , and activate the e-stop 285 for that vehicle specifically to disengage it. Both the e-stop 284 and e-stop controller 285 may be implemented using a general purpose computing device such as the computing system 900 illustrated with respect to FIG. 9 . [0047] Additional safety features may be integrated into the VSC 230 . For example, in some implementations, the VSC 230 may receive what is referred to as heartbeat signal from the ICS 220 that indicates that the IC 220 is receiving signals from OCU 250 . If the heartbeat signal is not received by the VSC 230 from the ICS 220 , the VSC 230 may immediately shut down or disengage the vehicle, or alternatively may gradually slow the vehicle. By providing the safety functionality within the VSC 230 rather than the ICS 220 , the safety of the vehicle is not compromised by the particular sensors or peripheral devices 210 that are connected to the ICS. 220 [0048] The ICS 220 may further include a Shared Control Module (SCM) 240 . The SCM 240 may be a computing device (such as the computing system 900 ) and may provide the API functionality described herein. The ICS 220 may allow one or more customized control modules to interface with the ICS 220 and the one or more peripheral devices 210 that are connected to the ICS 220 including the VSC 230 . Thus, for example, a user may interact with the sensors connected to the ICS 220 using the API provided by the SCM 240 . The SCM 240 may then translate the various function calls of the API into the particular format or protocols expected by each peripheral device 210 . Similarly, a user may create an application that controls the vehicle using the API without knowing the particular functions or protocols used by the vehicle. The SCM 240 may then translate the function calls of the API according to various functions and/or protocols that are expected by the vehicle. Thus, the SCM 240 provides a layer of abstraction of the vehicle and peripheral device 210 interfaces that allows a single application to work with a wide variety of vehicle and peripheral device types. [0049] The OCU 250 may include a hand held controller (HHC) 280 . The HHC 280 may be a controller that provides control data or instructions to the ICS 220 and/or directly the VSC 230 . In some implementations, the HHC 280 may include one or more analogue control sticks and/or buttons that may be used to control the steering, braking, throttle, and other functionality of the vehicle. The HHC 280 may further control other operations of the vehicle including locks, lights, and horn, for example. In some implementations, the HHC 280 may also control the operation of one or more sensors or other peripheral devices 210 of the ICS 220 . The HHC may include a GPS, or other location determination means, and may provide the location of the HHC along with any control data to the ICS/VSC. The HHC 280 may be ergonomic, waterproof, and rugged. An example schematic of the HHC is illustrated in FIG. 5 . Note that all wireless communication described herein between the OCU 250 and the VICS 200 may be encrypted or otherwise protected. [0050] In addition to the HHC 280 , in some implementations, the OCU 250 may further include one or more Remote Viewing Stations (RVS) 260 . The RVS 260 may be a rugged portable system allowing one or more users to monitor the ICS 220 and/or VCS 230 remotely. The RVS 260 may include a power source such as a battery 262 , and may allow for the charging one or more devices 270 including the HHC 280 . The RVS 260 is intended to be easily carried by an operator, or may be stored in a vehicle (including the unmanned vehicle) until needed. The RVS 260 may be implemented using a general purpose computing device such as the computing system 900 illustrated with respect to FIG. 9 . [0051] The RVS 260 may further include a wireless interface 261 . The wireless interface 261 may include one or more radios and/or antennas, and may be used to receive data (such as location information, speed, etc.) from the ICS 220 and/or VSC 230 and may make the received data available to one or more devices 270 such as smart phones, tablets, laptops, etc. In some implementations, the RVS 260 may use the wireless interface 261 to create a protected Wi-Fi network that operators may connect to in order to view sensor data on their devices 270 . In some implementations, the operators may use their personal devices to control the vehicle, or to control the operation of one or more sensors or peripheral devices 210 of the ICS 220 and/or VSC 230 . The RVS 260 may pass on any commands or instructions received by the RVS 260 to the ICS 220 or VSC 230 depending on the implementation. [0052] The RVS 260 may further include one or more safety features. For example, the RVS may include an e-stop controller 285 . [0053] FIG. 3 is an illustration of an example scenario where an OCU 250 is used to control a vehicle 300 through a VICS 200 . In the example shown, the vehicle 300 is a bulldozer. However, a variety of vehicles may be supported. [0054] The vehicle 300 includes a vehicle system 310 that is connected to the VCS 230 of the VICS 2000 . The vehicle system 310 may be a drive by wire system, and may include an interface such as a 50 pin signal connector through which the VCS 230 may provide commands to the vehicle 300 , and may receive information from the vehicle such as speed, oil pressure, fuel level, engine temperature, etc. The VCS 230 may provide commands to the vehicle systems 310 to activate various controls associated with the vehicle 300 including lights, throttle, and brakes, for example. [0055] The VCS 230 may receive operating instructions from the HHC 280 , and may provide the instructions to the vehicle systems 310 . Alternatively, or additionally, the VCS 230 may receive instructions from one or more devices associated with the RVS 260 . For example, an operator of the HHC 280 , may use a stick or control pad associated with the HHC 280 to cause the vehicle 300 to turn left. The HHC 280 may then provide a corresponding command wirelessly to the VCS 230 . The VCS 230 may generate a command that may cause the vehicle system 310 to turn left, and may provide it to the vehicle systems 310 . The vehicle 300 may then turn left. [0056] The VSC 230 may provide the status information from the vehicle systems 310 to the ICS 220 . As shown the ICS 220 may be attached to the roof or exterior of the vehicle to maximize the wireless range of the ICS 220 . The ICS 220 may then provide the status information to the RVS 260 where the status information may be displayed or made available by the RVS 260 . [0057] In addition, the ICS 220 may determine a location of the vehicle 300 , and may receive data from one or more peripheral devices 210 attached to the ICS 200 , such as a camera. The location, peripheral device 210 data, and VCS 230 data may be provided to the RVS 260 where the data may be viewed by an operator of the RVS 260 and/or one or more devices 270 . [0058] For example, the RVS 260 may receive the current speed and location of the vehicle 300 from the VSC 230 , along with video from a video camera peripheral device 210 mounted on the top of the vehicle 300 . An operator of the RVS 260 may view a map that indicates the location of the vehicle 300 , along with the video received from the peripheral device 210 . In addition, the locations of other vehicles 300 may also be displayed on the map, and the operator may use the RVS 260 (or other connected device 270 ) to select the vehicle 300 whose video data the operator desires to view. [0059] The VICS 200 also includes an e-stop 284 . The e-stop 284 may be placed on the outside of the vehicle 300 so that an operator may manually activate the button or switch associated with the e-stop to halt the vehicle 300 . When activated the e-stop 284 may send a signal to one or both of the ICS 220 and VSC 230 to cause the vehicle 300 to be immediately stopped. [0060] In addition, the OCU 250 includes a corresponding e-stop controller 285 that can be used to halt the vehicle 300 . The e-stop controller 285 may be a standalone device or may be integrated into some of all of the HHC 280 and the RVS 260 . An operator may activate the e-stop controller 285 and the controller 285 may provide a stop signal that is received directly by the e-stop 284 or indirectly by either the VCS 230 or the ICS 220 . In response to receiving the stop signal the vehicle 300 may halt as if the corresponding switch on the e-stop 284 had been activated. [0061] Depending on the implementation, e-stop controller 285 and the e-stop 284 may include additional safety and/or failsafe features. For example, the e-stop 284 may monitor the state of the wireless connection between them. Should the e-stop 284 detect that the connection has been severed; the e-stop 284 may immediately halt the operation of the vehicle 300 as if the e-stop controller 285 had issued a stop command. Should the wireless connection be restored, the e-stop 284 may reactivate the vehicle 300 . The wireless connection based failsafe may be implemented in hardware, for example [0062] As another level of failsafe, the e-stop 284 may periodically receive a heartbeat signal from the e-stop controller 285 . Should the e-stop 284 not receive the heart beat signal from the e-stop controller 285 within a defined time interval, the e-stop 284 may deactivate the vehicle 300 . [0063] In addition, the e-stop 284 may also send a heartbeat signal to the e-stop controller 285 . Should the e-stop controller 285 not receive the signal, the controller 285 may send a stop signal, and then may deactivate the wireless connection between the e-stop controller 285 and the e-stop 284 . Should the e-stop 284 not receive or understand the stop signal because of a software malfunction, the hardware implemented failsafe will cause the e-stop 284 to deactivate the vehicle 300 . Alternatively, the e-stop controller 285 may deactivate the wireless connection without sending the stop signal, which will similarly result in the e-stop 284 deactivating the vehicle 300 . [0064] FIG. 4 is an illustration of an example VCS 230 . As shown, the VCS 230 includes several components including a processing means 410 , wireless interface 405 , an ICS interface 406 , a vehicle interface 407 , and a fuse 409 . More or fewer components may be supported. [0065] The vehicle interface 407 may allow the VCS 230 to send data to, and receive data from, the vehicle systems 310 . The data that the VCS 230 sends to the vehicle systems 310 may be control data such as instructions to apply brakes, increase or decrease speed, steering instructions, and instructions to turn on one or more lights. The received data may include status data such as information about an amount of remaining fuel and other diagnostic information about the vehicle. In some implementations, the vehicle interface 407 may be a 50 pin connector. However, other types of wired or wireless interfaces may be used. [0066] The ICS interface 406 may allow the VCS 230 to send data to, and receive data from, the ICS 220 . As described previously, in some implementations, the ICS 220 may be externally mounted to the vehicle and may include one or more peripheral devices 210 such as cameras or other sensors. In addition, the ICS 220 may receive control commands or instructions from one or more of the HHC 280 or the RVS 260 , and may also provide information to the RVS 260 and/or HHC 280 regarding the status of the associated vehicle and data from the peripheral devices 210 . Accordingly, the ICS interface 220 may allow the ICS 220 to pass any received control commands to the VCS 230 , as well as the VCS 230 to provide any requested status information received from the vehicle systems 310 to the ICS 200 . In some implementations, the ICS 406 may be a 24 pin signal connector. However, other types of wired or wireless interfaces may be used. [0067] The wireless interface 405 may receive and/or transmit data to one or more of the RVS 260 and the HHC controller 280 . The received data may include control instructions from the HHC controller 280 and/or the RVS 260 . The transmitted data may include status information from the vehicle systems 310 , sensor information, and location information, for example. The wireless interface 405 may include one or more antennas and may support a variety of standards, protocols, and frequencies such as Wifi, cellular, Bluetooth, 1.3 Ghz, 2.4 Ghz, 5.8 Ghz, and 900 Mhz. In some implementations, the control signals may be received using a different frequency and/or antennae than is used to send status information. [0068] The processing means 410 may execute software that manages and routes data to and from the various components of the VCS 230 . For example, the processing means 410 may receive control instructions from one or more of the ICS interface 406 and/or wireless interface 405 and may pass the control instructions to the vehicle systems 310 via the vehicle interface 407 . Similarly, the processing means 410 may provide status data received from the vehicle systems 310 via the vehicle interface 407 to one or more of the wireless interface 405 and the ICS interface 406 . When routing data to and from the various components of the VCS 230 the processing means may transform or format the data into whatever formats are expected or supported by the receiving components. The processing means 410 may include a processor and memory. [0069] The processing means 410 may further interface with an e-stop 284 . The e-stop 284 may generate a stop signal that is received by the processing means 410 . Upon receipt of the stop signal, the processing means may instruct the vehicle systems 310 via the vehicle interface 407 to immediately halt the vehicle. Alternatively, or additionally, the e-stop 284 may generate a heartbeat signal that is received by the processing means 410 . In the event that the heartbeat signal ceases (either because the e-stop 284 has been activated or malfunctioned) the processing means 410 may instruct the vehicle systems 310 via the vehicle interface 407 to immediately halt the vehicle. [0070] The processing means 410 may further receive power through the fuse 409 , and may distribute the power to the various components of the VCS 230 via a bus. The fuse 409 may receive power from a vehicle power source 420 associated with the vehicle. The power may be received via a 4 pin power connector; however other connectors or connector types may be used. The fuse 409 may limit the amount of power that the VCS 230 may draw from the vehicle at any time thereby preventing the VCS 230 from inhibiting the amount of power that is available to the vehicle. In some implementations, the power from the fuse 409 may be further distributed to the ICS 220 via the ICS 406 interface. [0071] While not shown, the VCS 230 may include additional components or sensors such as an accelerometer, a GPS, or other location determination means. In addition, the VCS 230 may include a battery or other power source that is independent of the vehicle power source 420 . [0072] FIG. 5 is an illustration on an example HHC 280 . As shown the HHC 280 include one or more components including, but are not limited to a wireless interface 501 , sensors 502 , battery 504 , display 505 , user controls 540 , an e-stop controller 530 , and a processing means 510 . More or fewer components may be supported. [0073] The wireless interface 501 may receive and/or transmit data to one or more of the ICS 220 and the VCS 230 . As described above, the HHC 280 may be used by an operator to control a vehicle via one or more of the ICS 220 and the VSC 230 . The received data may include status information from the vehicle systems 310 , location information associated with the vehicle, vehicle sensor data, and peripheral device 210 data, for example. The transmitted data may include control data and other instructions generated by the operator of the HHC 280 . The wireless interface 501 may include one or more antennas and may support a variety of standards, protocols, and frequencies such as Wifi, cellular, Bluetooth, 2.4 Ghz, 5.8 Ghz, and 900 Mhz. In some implementations, the control signals may be sent using a different frequency and/or antennae than is used to receive status information or peripheral device 210 data. [0074] The HHC 280 may include user controls 540 . The user controls 540 may include a variety of input means such as buttons and joysticks. The input means may be digital, analogue or some combination of both. The input means may be mapped to variety of vehicle systems 310 and controls such as throttle, brakes, and steering. In addition, one or more of the input means may be mapped to one or more peripheral devices 210 such as lights, camera, or weapons systems. The particular mapping of the user controls to the vehicle systems 310 and/or peripheral devices 210 may be customized by an operator or administrator, for example. [0075] The HHC 280 may further include a display 505 . The display 505 may be used to display data received by the HHC 280 from the ICS 220 and/or the VSC 230 . For example, the VSC 230 may provide the HHC 280 with information about the vehicle such as speed, temperature, and location. The HHC 280 may display the information to an operator on the display 505 . Alternatively, or additionally the HHC 280 may receive video data from a peripheral device 210 of the ICS 220 and may display the video data to the operator on the display 505 . The display 505 may include a variety of display types including LCD and OLED. Other types of displays may be used. [0076] The HHC 280 may include a variety of sensors 502 . The sensors 502 may include a variety of sensor types including a location determination means such as a GPS, an accelerometer, a gyroscope, thermometer, impedance sensor, camera, fingerprint reader and a light sensor. Other types of sensors may be used. The data from the sensors 502 may be used to implement various safety and security related features. [0077] For example, the sensors 502 may be used to determine if an operator is currently holding the HHC 280 . For example, a sudden large acceleration detected by an accelerometer may indicate that the HHC 280 has been dropped. Similarly, because operators do not typically stand completely still, there is an expected amount of background movement or acceleration that is associated with being held still by an operator. If no acceleration is detected, or the detected acceleration is otherwise outside of this expected amount, then the user may have either placed the HHC 280 down or may otherwise be impaired. If any of the above conditions are detected, then the HHC 280 may be deactivated, or the HHC 280 may send the ICS 220 or VSC 230 a signal to deactivate the vehicle. [0078] In another example, a gyroscope sensor or magnetometer of the HHC 280 may detect the orientation of the HHC 280 and may deactivate the HHC 280 if the orientation is outside of an acceptable range. For example, if the HHC 280 is in an orientation that implies that the operator is lying down, upside down, or in any other unacceptable operating position, the HHC 280 may be deactivated. The ICS 220 and/or VSC 230 may be similarly also be deactivated as a result of the HHC 280 deactivation. The camera, light sensor, and/or impedance sensor may similarly be used to determine if the HHC 280 is being held by a user. [0079] With respect to security, the camera, fingerprint reader, and impedance sensor, alone or in combination, may be used to authenticate an operator of the HHC 280 . If an operator is not an authorized operator, or otherwise cannot be authenticated, the HHC 280 may be disabled along with the associated vehicle. [0080] The processing means 510 may execute software that manages and routes data to and from the various components of the HHC 280 , as well as perform any processing related to the display 505 , sensors 502 , and user controls 540 . For example, the processing means 510 may receive indications of one or more button actuations from the user controls 540 , may determine corresponding commands and/or instructions. These instructions may be then provide to the wireless interface 501 for transmission to the ICS 220 and/or VSC 230 . Similarly, the processing means 510 may receive location or video data from the ICS 220 , and may format or process the received data into a format that is suitable for display on the display 505 . The processing means 510 may further implement the various safety and authentication features described above. [0081] The processing means 510 may further interface with an e-stop controller 530 . The e-stop controller 530 may be mapped to a particular button or switch of the user controls 540 , and when actuated may cause a stop signal to be sent to the processing means 510 . Upon receipt of the stop signal, the processing means 510 may send a corresponding stop signal or instruction via the wireless interface 510 to an associated e-stop 284 of the controlled vehicle. Depending on the implementation, the e-stop controller 530 may include its own processing means and wireless interface so that the other operations of the HHC 280 do not impede or interfere with the operation of the e-stop controller 530 . [0082] FIG. 6 is an illustration of an example e-stop 284 . The e-stop 284 may include a plurality of components including a wireless interface 601 , a hardware fail safe 605 , a software failsafe 606 , a processing means 610 , a locating means 615 , a power supply 608 , and a manual input 609 . More or fewer components may be supported. As described above, an e-stop 284 may be paired with a vehicle, manufacturing device, or other machinery, and may allow one or more users to immediately stop the operation of the paired machinery or vehicle by activating either a button or switch attached to the e-stop 284 , or through one or more wireless e-stop controllers 285 . The e-stop 284 may halt the operation of a vehicle or machinery by sending a stop signal, for example. [0083] The e-stop 284 may include a wireless interface 601 . The wireless interface may include at least one antenna or radio and may be used to receive data from an e-stop controller 285 . A variety of communication standards, protocols, and frequencies such as Wifi, cellular, Bluetooth, 1.3 Ghz, 2.4 Ghz, 5.8 Ghz, and 900 Mhz may be supported by the wireless interface 601 . In some implementations, the e-stop 284 may periodically send a heartbeat signal to the e-stop controller 285 indicating that the e-stop 284 is operating correctly. [0084] To prevent malfunction of the e-stop 284 , the e-stop 284 may include a two stage failsafe system. The system may include the hardware failsafe 605 and the software failsafe 606 . The hardware failsafe 605 may determine whether there is an active connection with the e-stop controller 285 and the e-stop 284 . If at any time the wireless connection between the e-stop controller 285 and the e-stop 284 fails or is interrupted, the hardware failsafe 605 may trigger the stop signal to halt the vehicle or machinery. [0085] The software failsafe 605 may monitor the received signal for one or more of a heartbeat signal and a stop signal from the e-stop controller 285 . If the stop signal is received from the software failsafe may trigger the stop signal to halt the vehicle or machinery. The heartbeat signal may signify that the e-stop controller 285 is operating correctly, thus if the heartbeat signal ceases to be received from the e-stop controller 285 , the software failsafe 605 may similarly trigger the stop signal to halt the vehicle or machinery. [0086] As may be appreciated, the hardware failsafe 605 may allow the e-stop controller 285 to stop the associated vehicle or machinery even where the software failsafe 606 has failed. For example, the e-stop controller 285 may stop receiving the heartbeat signal from the e-stop 284 . Because the heartbeat signal is not being received, there may be a software malfunction of the software failsafe 606 that is preventing the heartbeat signal from being generated. However, because there is a software error, even if the e-stop controller 285 were to send a stop signal to the software failsafe 606 , there is a risk that the software failsafe 606 may not respond correctly. Accordingly, rather than, or in addition to sending the stop signal, the e-stop controller 285 may deactivate the wireless connection between the e-stop controller 285 and the e-stop 284 . The deactivation of the wireless connection will be detected by the hardware failsafe 605 , and may cause the hardware failsafe 605 to trigger the stop signal to halt the vehicle or machinery. Because the hardware failsafe 605 is implemented using hardware, rather than software, the hardware failsafe 605 is not affected by software malfunctions. [0087] The processing means 610 may execute software that manages and routes data to and from the various components of the e-stop 284 , as well as perform any processing related to the software failsafe 605 . [0088] The locating means 615 may determine a current location of the e-stop 284 . The locating means 615 may be implemented using a variety of location determination technologies including GPS. The processing means 610 may use the determined location to perform some additional safety functionality. For example, the e-stop controller 285 may periodically transmit its location to the e-stop 284 . The processing means 610 may compare the location of the e-stop controller 285 with the location of the e-stop 284 and may determine if they exceed a minimum separation distance. And if so, the processing means 610 may trigger the stop signal to halt the vehicle or machinery. Alternatively, the e-stop 285 may provide its location to the e-stop controller 285 , and the e-stop controller 285 may determine if the maximum distance has been exceeded. [0089] The e-stop 284 may further include the power supply 608 . The power supply 608 may be a battery, or may be power received from the associated vehicle or machinery, for example. Any type of battery may be used. In some implementations, the e-stop 284 may trigger the stop signal to halt the vehicle or machinery should the remaining battery fall below a threshold. [0090] The e-stop 284 may further include a manual input 609 . The manual input 609 may be a button, switch or other input means. When actuated, the manual input 609 may trigger the stop signal to halt the vehicle or machinery. The manual input may be implemented using hardware to prevent malfunction in the event of a software failure. [0091] FIG. 7 is an illustration of a system of distributed e-stops 284 and e-stop controllers 285 . As shown the system includes a plurality of e-stops 284 a - d (collectively referred to as e-stops 284 ) and a plurality of e-stop controllers 285 a - c (collectively referred to as e-stop controllers 285 ). While only four e-stops 284 and three e-stops controllers 285 are shown, it is for illustrative purposes only. There is no limit to the number of such devices that may be supported. [0092] As shown, together, the e-stops 284 (and e-stop controllers 285 ) may form a mesh wireless network. When an e-stop controller 285 desires to send a signal (such as a stop signal) to particular e-stop, the controller 285 may send it to any available e-stop 284 , which may then forward the signal to the specified e-stop 285 . For example, a user of the e-stop controller 285 c may wish to stop the machinery associated with the e-stop 284 c . Depending on the implementation, the user may select the e-stop 284 c from a list of e-stops 285 on a display associated with the e-stop controller 285 c , or may actuate an input of the e-stop controller 285 c that has been mapped to the e-stop 284 c . After selecting the e-stop 284 c , the stop signal may be sent to the e-stop 284 d because that is the closest e-stop 284 to the e-stop controller in the mesh network. The e-stop 284 d may then forward the signal to the e-stop 284 c , which may then halt or stop its associated machinery or vehicle. Any system method or technique for mesh networking may be used. [0093] In some implementations, each e-stop controllers 285 may be paired with one or more of the e-stops 284 and may only halt the machinery or vehicle associated with an e-stop 285 that is paired with. Alternatively, one or more of the e-stop controllers 285 may stop any of the e-stops 284 that are available. The e-stop controllers 285 may be manually paired with a particular e-stop 284 by a user or administrator. Alternatively, the e-stop controllers 285 may automatically be paired with the e-stops 284 that they are closest to based on location data associated with the e-stop controllers 285 and the e-stops 284 . [0094] In another implementation, a master e-stop controller 285 may be provided. The master e-stop controller 285 may override the stop signal sent by the other e-stop controllers 285 , and may therefore restart a halted vehicle or machinery. The master e-stop controller 285 may also be able to stop any available e-stop 284 on the network. The master e-stop controller 285 may automatically pair with a closest available mesh network. For example, a foreman may oversee several factories or construction sites. When the foreman visits a site or floor his or her controller 285 may discover the network of e-stops 284 at the site or floor and may immediately be able to halt any of the machines associated with the e-stops 284 [0095] In another implementation, the e-stop controllers 285 may be classified as either primary or secondary e-stop controller 285 . Each e-stop 284 may determine, based on location information, if it is within a minimum distance of any secondary e-stop controller 285 . If not, the e-stop 284 may halt its associated machinery. Whereas the primary controller 285 may not be subject to such distance requirements. [0096] For example, workers on a factory floor may be each assigned a secondary e-stop controller 285 , while a foreman on the floor is assigned a primary e-stop controller 285 . Each of the floor workers is tasked with overseeing a particular piece of machinery therefore the e-stops 284 may determine that at least one secondary e-stop controller 285 is within a monitoring distance of the machinery. On the other hand, the foreman may desire to be able to stop the operation of a piece of machinery while on the factory floor, but it is not crucial that he or she always be on the floor or within a particular distance of the e-stops 284 . [0097] FIG. 8 is an illustration of a method 800 implementing semi-autonomous navigation of an unmanned vehicle using the OIP 100 . The method 800 may automatically control the throttle of the unmanned vehicle allowing the user to focus on steering the unmanned vehicle or on operating one or more peripheral devices 210 . Because the user is not controlling the throttle, the functionality of the HHC 280 may be integrated into binoculars, or into a weapon such as rifle. For example, such an HHC 280 may be incorporated into a weapon using a single joystick allowing the user to have their weapon engaged while still controlling the unmanned vehicle. A screen may be provided on the weapon to display received video data from the ICS 220 associated with the vehicle to further assist the user in the control of the vehicle or to identify upcoming threats. The method 800 may be implemented by the ICS 220 and VSC 230 associated with a unmanned vehicle in conjunction with either the HHC 280 or the RVS 260 . [0098] At 801 a current location of an operator may be determined. The operator may be operating the HHC 280 and the current location may be determined by a GPS or other locating means associated with the HHC 280 . The operator of the HHC 280 may be following the vehicle that is being controlled by the HHC 280 . For example, the operator may be in a different vehicle, or may be walking. [0099] At 803 a leading distance between the operator and the unmanned vehicle may be determined. The leading distance may be the desired distance that may be maintained between the unmanned vehicle and the operator. The leading distance may be randomly determined or selected (to confuse possible threats), or may be a fixed distance. [0100] At 805 a current location of the vehicle is determined. The current location may be determined by the locating means associated with either the ICS 220 or the VSC 230 . [0101] At 807 a determination is made as to whether the distance between the current location of the operator and the unmanned vehicle is less than or greater than the leading distance. If the difference is less than the leading distance, then the VCS 230 or the ICS 220 may increase the speed of the vehicle at 807 . If the difference is greater than the leading distance, then the VCS 230 or the ICS 220 may decrease the speed of the vehicle at 809 . [0102] The inherent flexibility of the OIP 100 means that the possibilities for applications are quite numerous. Its ability to be adapted to control many vehicles of varying sizes and different operational environments enables the use of a single platform to develop a wide variety of solutions without needing to support a multitude of systems with redundant development efforts. Examples of such applications follow. [0103] Windowing System [0104] The SCM 240 may provide a unique windowed approach to share control of a vehicle between an operator and an autonomous sensor based algorithm. A window may be a period of time that the HHC 280 is permitted to control the vehicle, and may define a set of allowable controls for the HHC 280 and/or upper or lower bounds on the controls. Outside of the window, the SCM 240 may autonomously control the vehicle. While the operator is using the HHC 280 to drive the vehicle, the SCM 240 may use sensor data and autonomy algorithms to define windows of allowable control commands to the VSC 230 . For example, the operator may instruct the vehicle to drive at a high speed using the HHC 280 , while the autonomy algorithm has determined that danger lies ahead. In response to the danger determination, the SCM 240 may create a window that provides an upper limit for the speed of the vehicle to the VSC 230 to ensure that speed is reduced and a safe speed is used. The VSC 230 may use the defined windows from the SCM 240 to manipulate the vehicle commands from the HHC 280 before ultimately driving the vehicle. If the danger still lies ahead, the SCM 240 may bring the vehicle to a stop or slowly start to steer the vehicle in a safe direction. If the SCM 240 determines that full autonomy is needed to complete a task, it may reduce the allowable window to a single point, thus taking the HHC out of the loop completely. [0105] Safe Takeover [0106] Another example is known as safe takeover. As described above, the OIP 100 allows for a variety unmanned vehicles to be operated remotely by a user through the HHC 280 , even in situations where the user may not have a clear line-of-sight of the unmanned vehicle. Accordingly, a user or administrator may use the OIP 100 to enforce a safety procedure that may be used to verify that the vehicle may be safely operated by the HHC 280 before the OIP 100 allows the HHC 280 to control the vehicle (i.e., takeover). [0107] In one implementation, the OIP 100 may force the user to actuate one or buttons or switches on the vehicle before the VSC 230 or ICS 220 will allow the HHC 280 to control the vehicle. The buttons or switches may be located at different locations on the vehicle to ensure that the user has verified that no lives or property will be damaged by the vehicle. The same takeover sequence may be used for each takeover, or may be randomized. The takeover sequence may be displayed to the user on the display of the HHC 280 . Such a safety procedure may be useful on a construction site or other work environment. The takeover sequence may be customizable by a user or administrator, or may be disabled depending on the implementation. [0108] Training Applications [0109] In some implementations, multiple HHCs 280 may be used to provide training for HHC 280 operators. For example, one HHC 280 may be the “Instructor” controller and another HHC 280 may be a “trainee” controller. The VSC 230 or ICS 220 may receive commands from either the instructor or the trainee controller, but when instructions are received from both controllers, or if there is a conflict between instructions that are received from the controllers, the instructions that are received from the instructor controller are followed. [0110] In another implementation, an instructor may view a video feed from an unmanned vehicle on a personal device through the RVS 260 . The unmanned vehicle may be controlled by a trainee using the HHC 280 . The instructor may use the personal device to provide instructions/and or critiques to the trainee that may be displayed to the trainee on the display of the HHC 280 or on a video feed that the trainee is otherwise viewing. The instructor may use the personal device to disable the unmanned vehicle or to otherwise take control of the vehicle away from the trainee if necessary. [0111] Safety Applications [0112] In another implementation, the ICS 220 may enforce a minimum distance between an unmanned vehicle and other users to ensure the safety of the users. For example, the ICS 220 may determine the distance between the unmanned vehicle and the HHC 280 (via GPS), and may disable the unmanned vehicle if the distance is less than a threshold distance. In another example, workers who operate close to unmanned vehicles may wear wireless sensors. If the ICS 220 determines that such a wireless sensor is within the threshold distance, the ICS 220 may disable the vehicle until the worker with the wireless sensor moves outside of the threshold distance. [0113] Instrument-Aided Precise Manipulation [0114] Integrating high-precision distance sensors into the ICS 220 allows the control of tools with extreme accuracy, even with significant standoff distances. Positioning a sensor on the manipulator arm of a robot gives the operator precise distance feedback between the arm and the object of interest. This simple feedback provides a sense of depth not available on a simple video screen, increasing the precision achievable while also reducing the cognitive workload on the operator. [0115] FIG. 9 shows an exemplary computing environment in which example embodiments and aspects may be implemented. The computing system environment is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality. [0116] Numerous other general purpose or special purpose computing system environments or configurations may be used. Examples of well known computing systems, environments, and/or configurations that may be suitable for use include, but are not limited to, personal computers, server computers, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, network PCs, minicomputers, mainframe computers, embedded systems, distributed computing environments that include any of the above systems or devices, and the like. [0117] Computer-executable instructions, such as program modules, being executed by a computer may be used. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Distributed computing environments may be used where tasks are performed by remote processing devices that are linked through a communications network or other data transmission medium. In a distributed computing environment, program modules and other data may be located in both local and remote computer storage media including memory storage devices. [0118] With reference to FIG. 9 , an exemplary system for implementing aspects described herein includes a computing device, such as computing system 900 . In its most basic configuration, computing system 900 typically includes at least one processing unit 902 and memory 904 . Depending on the exact configuration and type of computing device, memory 1404 may be volatile (such as random access memory (RAM)), non-volatile (such as read-only memory (ROM), flash memory, etc.), or some combination of the two. This most basic configuration is illustrated in FIG. 9 by dashed line 906 . [0119] Computing system 900 may have additional features/functionality. For example, computing system 900 may include additional storage (removable and/or non-removable) including, but not limited to, magnetic or optical disks or tape. Such additional storage is illustrated in FIG. 9 by removable storage 908 and non-removable storage 910 . [0120] Computing system 900 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computing system 1400 and includes both volatile and non-volatile media, removable and non-removable media. [0121] Computer storage media include volatile and non-volatile, and removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Memory 904 , removable storage 908 , and non-removable storage 910 are all examples of computer storage media. Computer storage media include, but are not limited to, RAM, ROM, electrically erasable program read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computing system 900 . Any such computer storage media may be part of computing system 900 . [0122] Computing system 900 may contain communications connection(s) 912 that allow the device to communicate with other devices and/or interfaces. Computing system 900 may also have input device(s) 914 such as a keyboard (software or hardware), mouse, pen, voice input interface, touch interface, etc. Output device(s) 916 such as a display, speakers, printer, etc. may also be included. All these devices are well known in the art and need not be discussed at length here. [0123] It should be understood that the various techniques described herein may be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the methods and apparatus of the presently disclosed subject matter, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other machine-readable storage medium where, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the presently disclosed subject matter. [0124] Although exemplary implementations may refer to utilizing aspects of the presently disclosed subject matter in the context of one or more stand-alone computer systems, the subject matter is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Still further, aspects of the presently disclosed subject matter may be implemented in or across a plurality of processing chips or devices, and storage may similarly be effected across a plurality of devices. Such devices might include personal computers, network servers, and handheld devices, for example. [0125] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

An open architecture control system is provided that may be used for remote and semi-autonomous operation of commercial off the shelf (COTS) and custom robotic systems, platforms, and vehicles to enable safer neutralization of explosive hazards and other services. In order to effectively deal with rapidly evolving threats and highly variable operational environments, the control system is built using an open architecture and includes a high level of interoperability. The control system interfaces with a large range of robotic systems and vehicles, autonomy software packages, perception systems, and manipulation peripherals to enable prosecution of complex missions effectively. Because the control system is open and does not constrain the end user to a single robotics system, mobile platform, or peripheral hardware and software, the control system may be used to assist with a multitude of missions beyond explosive hazard detection and clearance.

TECHNICAL FIELD The method described below relates to phase change inkjet printers, and more particularly to release agent application systems used in these printers. BACKGROUND Phase change inkjet printers receive phase change ink in a solid form and then melt the solid ink to produce liquid ink that is used to form images on print media. Phase change inkjet printers form images using either a direct or an offset (sometimes called indirect) print process. In a direct print process, melted ink is jetted directly onto print media to form images. In an offset print process, melted ink is jetted onto a surface of a rotating member, such as the surface of a rotating drum, belt, or band. Print media are moved proximate the surface of the rotating member in synchronization with the ink images formed on the surface. The print media are then pressed against the surface of the rotating member as the media passes through a nip formed between the rotating member and a transfix roller. The ink images are transferred and affixed to the print media by the pressure in the nip. Offset phase change inkjet printers utilize drum maintenance units (DMUs) to facilitate the transfer of ink images to the print media. A DMU is usually equipped with a reservoir that contains a fixed supply of release agent (e.g., silicon oil), and an applicator for delivering the release agent from the reservoir to the surface of the rotating member. One or more elastomeric metering blades are also used to meter the release agent on the transfer surface at a desired thickness and to divert excess release agent and un-transferred ink pixels to a reclaim area of the drum maintenance system. The collected release agent is filtered and returned to the reservoir for reuse. DMUs are typically provided in a modular form capable of being installed and removed from an imaging device as a self-contained functional unit. The fixed supply of release agent in a DMU provides adequate oil for image transfer for a limited number of prints depending on an average oil usage per print and the quantity of the oil in the reservoir. When the supply of release agent has been depleted, the DMU is removed and replaced with a DMU having a fresh supply of release agent. Replacing DMUs as they are depleted of release agent adds to the operating cost of an imaging device. Finding ways to reduce the amount of oil that is removed from a DMU over time can increase the useful life of the DMU and thus decrease the cost of operating an imaging device. SUMMARY A method of operating a printer operates a release agent system to apply release agent in a manner that conserves release agent stored in the release agent system. The method includes rotating an image receiving member of a printer at a first velocity, moving a metering blade of a release agent application system of the printer into engagement with a surface of the image receiving member, moving an applicator of the release agent application system into engagement with the surface of the image receiving member after the metering blade engages the surface of the image receiving member, disengaging the applicator from the surface of the image receiving member after a predetermined distance has been traveled by the rotating image receiving member, increasing rotation of the image receiving member to a second velocity that is greater than the first velocity after the applicator disengages from the surface of the image receiving member and while the metering blade remains in engagement with the surface of the image receiving member, and disengaging the metering blade from the surface of the image receiving member in response to the rotation of the image receiving member reaching the second velocity. A printer includes a release agent system that operates in a manner that conserves release agent stored in the release agent system. The printer includes a rotatable image receiving member having a surface on which ink images are formed, at least one printhead configured to eject ink onto the surface of the rotatable image receiving member, a release agent application system including: a reservoir containing a supply of release agent, an applicator configured to move into and out of contact with the surface of the rotatable image receiving member to enable the applicator to apply release agent from the reservoir to the surface when the applicator contacts the surface of the image receiving member, and a metering blade configured to move into and out of contact with the surface of the rotatable image receiving member to enable the metering blade to spread the release agent applied to the surface of the rotatable image receiving member. The printer also includes a controller operatively connected to the image receiving member, the applicator, and the metering blade, the controller being configured to rotate the image receiving member and to move the applicator and the metering blade to perform a maintenance cycle during which the controller operates the image receiving member to rotate at a first velocity, the controller operates the metering blade to move into contact with the surface of the rotatable image receiving member and to move the applicator into contact with the surface of the rotatable image receiving member until a predetermined distance has been traveled by the rotating image receiving member at which time the controller moves the applicator out of contact with the surface of the image receiving member, the controller operates the image receiving member to rotate at a second velocity that is greater than the first velocity after the applicator is disengaged from the surface of the rotatable image receiving member and while the metering blade contacts the surface of the rotatable image receiving member, and then operates the metering blade to move out of contact with the surface of the rotatable image receiving member after the rotation of the image receiving member reaches the second velocity. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an indirect phase change inkjet printing system including a rotatable image receiving member having an image transfer surface. FIG. 2 is a schematic view of drum maintenance system of the printing system of FIG. 1 in an engaged position with respect to the image transfer surface. FIG. 3 is a schematic view of the drum maintenance system of FIG. 2 in a disengaged position with respect to the image transfer surface. FIG. 4 is a flowchart depicting a standard DM cycle. FIG. 5A is a flowchart depicting a Slow Auto DM cycle. FIG. 5B is a graph depicting the timing sequence of the Slow Auto DM cycle of FIG. 5A . FIG. 6 is a flowchart depicting a print process that incorporates the Slow Auto DM cycle of FIG. 5 . DETAILED DESCRIPTION The description below and the accompanying figures provide a general understanding of the environment for the method disclosed herein as well as the details for the method. In the drawings, like reference numerals are used throughout to designate like elements. The term “printer” as used herein encompasses any apparatus that generates an image on media with ink. As used in this document, “ink” refers to a colorant that is liquid when applied to an image receiving member. For example, ink may be aqueous ink, ink emulsions, melted phase change ink, and gel ink that has been heated to a temperature that enables the ink to be liquid for application or ejection onto an image receiving member and then return to a gelatinous state. The term “printer” includes, but is not limited to, a digital copier, a bookmaking machine, a facsimile machine, a multi-function machine, or the like. The terms “simplex” and “duplex” used in reference to the term “prints” describe whether an ink image is formed on one side of the sheet, i.e., “simplex print,” or both sides of the print, i.e., “duplex print.” Similarly, as used herein, the “simplex side” or “first side” of a print refers to the side of a print that is positioned to receive an image in a printer. A “print” refers to a substrate of media on which an ink image has been formed. FIG. 1 is a side schematic view of a phase change inkjet printer 10 configured to form ink images on an image receiving, bearing, or contacting member 34 , referred to herein as a drum. The ink image is transferred to a media substrate to form a print. The printer 10 is equipped with a release agent application system 100 , also referred to as a drum maintenance unit (DMU), having an applicator for applying release agent, such as silicone oil, to the surface of the drum and a metering blade for spreading the release agent on the surface to a uniform thickness. Excess release agent and un-transferred ink pixels are removed from the drum as the metering blade is applied to the surface of the drum is diverted to a reclaim area of the DMU. The collected release agent is filtered and returned to the reservoir for reuse. The DMU 100 is configured to perform a drum maintenance (DM) cycle for each print produced by the printer 10 . As part of a DM cycle, the release agent application system 1) applies and meters release agent on the surface of the drum before each print cycle, and 2) removes and stores any excess oil, ink and debris from the surface of the drum after each print cycle. As described in this document, a Slow Auto DM cycle has been developed to reduce the amount of oil removed from a DMU during a DM cycle. During a Slow Auto DM cycle, the drum is rotated at a velocity that is reduced relative to a default velocity used during a standard DM cycle. Testing has shown that the amount of release agent deposited onto the surface of an image receiving member, such as drum 30 , during a standard DM cycle is directly proportional to the rotational velocity of the drum during metering. By reducing the velocity of the drum, the amount of release agent deposited onto the surface of the drum is decreased. The applicator roller floods the drum with oil during a standard DM cycle and a Slow Auto DM cycle. However, during a slow auto DM cycle, the metering blade is more effective at removing the applied oil from the drum due to the reduced drum velocity during wiping. Therefore, less oil remains on the drum after the metering blade interacts with the drum surface during a slow auto DM. The Slow Auto DM cycle is performed at the conclusion of any print job when no print jobs are in a print job queue. The slow auto DM cycle is also performed if a job in the queue is being ripped by the image processing engine. The Slow Auto DM cycle is also performed when the printer is powered on and when the printer transitions from a standby state to an active printing state. The Slow Auto DM cycle results in less oil being deposited onto the drum for the first page of the next print job entering the print job queue or for the first and the second pages if two pages are formed on the imaging drum during an imaging phase. Because the majority of print jobs generated in a typical office environment are short, e.g., 1-3 pages, the print job queue is frequently empty following execution of a print job. As a consequence, a Slow Auto DM cycle is performed after many print jobs and the decreased oil deposition for the first pages of the following print jobs significantly reduces the amount of oil removed from the DMU over time. Consequently, the supply of release agent is reduced more slowly with the expectation that the life of the DMU is increased. Although the Slow Auto DM cycle is described below in conjunction with a release agent application system used in a phase change inkjet printer, a Slow Auto DM cycle can be used with the release agent or lubricant application systems of other printers. For example, a Slow Auto DM cycle can be used with a release agent application system that operates on a fuser roll in a xerographic printer or on an ink spreader in a phase change ink printer that prints directly on media. FIG. 1 depicts the relationship between the DMU 100 and the other components of the exemplary phase change inkjet printer 10 . The printer 10 includes a housing 11 that supports and at least partially encloses an ink loader 12 , an image forming system 26 , a media supply and handling system 48 , and a control system 68 . The ink loader 12 receives and delivers solid ink units 14 to a melting device 20 for generation of liquid ink. The image forming system 26 includes at least one printhead 28 having a plurality of inkjets that is fluidly connected to a reservoir holding melted ink to receive the ink melted by the melting device 20 . Control system 68 operates the inkjets in the printhead 28 to eject drops of liquid ink onto the image transfer surface 30 . The media supply and handling system 48 extracts media sheets from one or more media trays 58 in the printer 10 , synchronizes delivery of the media sheets to a transfix nip 44 for the transfer of an ink image from the image receiving surface 30 to the media sheets as they pass through the nip, and then delivers the prints to an output area. Control system 68 aids in operation and control of the various subsystems, components, and functions of the printer 10 . The control system 68 is operatively connected to one or more image data sources, such as a scanner, to receive and manage image data from the sources. The control system 68 also generates control signals that are delivered to the components and subsystems of the printer. Some of the control signals, such as firing signals for the printhead, are based on image data, while other control signals regulate the operating speeds, power levels, timing, actuation, and other parameters, of the printer components to cause the printer 10 to operate in various states, modes, or levels of operation, referred to collectively herein as operating modes. These operating modes include, for example, a startup or warm up mode, shutdown mode, various print modes, maintenance modes, and power saving modes. The control system 68 is configured to ascertain relevant print job characteristics and attributes in a suitable manner, such as by parsing information in image data files or by monitoring the components and sensors of the printer. The print characteristics and attributes obtained by the control system include print media type, print size, fill or coverage level (i.e., percent of the print covered with ink), and whether the print is a simplex (image on one side) or a duplex (image on both sides) print. The control system 68 includes a controller 70 and electronic storage or memory 74 . The controller 70 has a processor, such as a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) device, or a micro-controller. Among other tasks, the processor executes programmed instructions that are stored in the memory 74 . The controller 70 executes these instructions to operate the components and subsystems of the printer. Any suitable type of memory or electronic storage may be used. For example, the memory 74 may be a non-volatile memory, such as read only memory (ROM), or a programmable non-volatile memory, such as EEPROM or flash memory. The controller 70 is operatively connected to a user interface (UI) 78 . User interface (UI) 78 comprises a suitable input/output device positioned on the printer 10 to enable operator interaction with the control system 68 . For example, UI 78 may include a keypad and display (not shown). The controller 70 is operatively connected to the user interface 78 to receive signals indicative of selections and other information input to the user interface 78 by a user or operator of the device. Controller 70 is also operatively connected to the user interface 78 to display information to a user or operator including selectable options, machine status, consumable status, and the like. The controller 70 is operatively connected to a communication link 84 , such as a computer communication network, for receiving image data files and user interaction data from remote locations. The ink loader 12 of the printer 10 is configured to receive phase change ink in solid form, such as blocks of ink 14 , which are commonly called ink sticks. The ink loader 12 includes feed channels 18 into which ink sticks 14 are inserted. Although a single feed channel 18 is visible in FIG. 1 , the ink loader 12 includes a separate feed channel for each color or shade of color of ink stick 14 used in the printer 10 . The feed channel 18 guides ink sticks 14 toward the melting device 20 at one end of the channel 18 where the sticks are heated to a phase change ink melting temperature to melt the solid ink and form liquid ink. Any suitable melting temperature may be used depending on the phase change ink formulation. In one embodiment, the phase change ink melting temperature is in a range of approximately 80° C. to approximately 130° C. In some embodiments, alternative ink loader configurations, ink forms, and ink formulations are used. The melted ink from the melting assembly 20 is directed gravitationally or by actuated systems, such as pumps, to a melt reservoir 24 . A separate melt reservoir 24 may be provided for each ink color, shade, or composition used in the printer 10 . Alternatively, a single reservoir housing may be compartmentalized to contain the differently colored inks. As depicted in FIG. 1 , the ink reservoir 24 comprises a printhead reservoir that supplies melted ink to inkjet ejectors 27 formed in the printhead(s) 28 . The ink reservoir 24 may be integrated into the printhead 28 . In alternative embodiments, the reservoir 24 is a separate or independent unit from the printhead 28 . Each melt reservoir 24 may include a heating element (not shown) operable to heat the ink contained in the corresponding reservoir to a temperature suitable for melting the ink and/or maintaining the ink in liquid or molten form, at least during appropriate operational states of the printer 10 . The image forming system 26 includes at least one printhead 28 . One printhead 28 is shown in FIG. 1 although any suitable number of printheads 28 may be used. The inkjets 27 of the printhead 28 are operated with firing signals generated by the control system 68 to eject drops of ink toward the image receiving surface 30 . The printer 10 of FIG. 1 is an indirect printer configured to use an indirect printing process in which the drops of ink are ejected onto the intermediate transfer surface 30 and then transferred to media sheets. In alternative embodiments, the printer 10 is configured to eject the drops of ink directly onto media, which may be in sheet or continuous web form. The image receiving member 34 is shown as a drum in FIG. 1 , although in alternative embodiments the image receiving member 34 is a moving or rotating belt, band, roller or other similar type of structure. A transfix roller 40 is configured for movement into and out of engagement with the image receiving member. The control system 68 selectively operates an actuator (not shown) to implement this movement. The transfix roller 40 is loaded against the transfer surface 30 of the image receiving member 34 to form a nip 44 through which sheets of print media 52 pass. The sheets are fed through the nip 44 in timed registration with an ink image formed on the transfer surface 30 by the printhead 28 . Pressure (and in some embodiments heat) is generated in the nip 44 to facilitate the transfer of the ink drops from the surface 30 to the print media 52 in conjunction with release agent to substantially prevent the ink from adhering to the image receiving member 34 . The image receiving member 34 includes an actuator 144 ( FIGS. 2 and 3 ) that drives the image receiving member to rotate at various predetermined velocities in response to control signals received from the control system 68 . The various velocities include an imaging velocity and a transfixing velocity. The control system 68 is configured to cause the image receiving member 34 to rotate at the imaging velocity during imaging operations, i.e., when the ink images are formed on the transfer surface, and to cause the image receiving member 34 to rotate at the transfixing velocity during transfixing operations, i.e., when the print media are fed through the nip 44 in timed registration with the ink images formed on the transfer surface 30 . The imaging and transfixing velocities may be different for different print jobs depending upon the characteristics of the print job, such as print job type, media type, job size, resolution, and coverage level, as well as drum surface condition, pixel transfer efficiency, image durability, properties of the oil, metering blade geometry, and desired oil film thickness. In one embodiment, the imaging velocity and the transfixing velocity are each between approximately 1200 mm/s and 2000 mm/s although any suitable velocity or range of velocities may be used for one or both of the imaging and transfixing velocities. The normal, or default, velocity of the image receiving member, or drum, during a standard DM cycle is typically dictated by the imaging and transfixing speed requirements for the current print. For example, the drum velocity at the beginning of a DM cycle at which time the metering blade typically is moved into engagement with the image receiving member, usually corresponds to the imaging velocity for the image currently being printed, while the drum velocity at the end of the DM cycle at which time the metering blade typically is moved out of engagement with the image receiving member, usually corresponds to the transfixing velocity for the ink image being transferred to media. These values are chosen to maximize print speed and minimize image quality defects. As explained below, the control system is also configured to actuate the image receiving member to rotate at a predetermined reduced velocity during a Slow Auto DM cycle. In one embodiment, the reduced velocity for the Slow Auto DM cycle is approximately 200-500 mm/s, and, in one particular embodiment, is 254 mm/s. Referring to FIG. 1 , the media supply and handling system 48 of printer 10 transports print media along a media path 50 that passes through the nip 44 . The media supply and handling system 48 includes at least one print media source, such as supply tray 58 . The media supply and handling system also includes suitable mechanisms, such as rollers 60 , which may be driven rollers or idle rollers, as well as baffles, deflectors, and the like, for transporting media along the media path 50 . Media conditioning devices may be positioned at various locations along the media path 50 to prepare the print media thermally to receive melted phase change ink. In the embodiment of FIG. 1 , a preheating assembly 64 is utilized to bring print media on media path 50 to an initial predetermined temperature prior to reaching the nip 44 . Media conditioning devices, such as the preheating assembly 64 , may rely on radiant, conductive, or convective heat or any combination of these heat forms to bring the media to a target preheat temperature, which in one practical embodiment, is in a range of about 30° C. to about 70° C. In alternative embodiments, other thermal conditioning devices may be used along the media path before, during, and after ink has been deposited onto the media. The release agent application system 100 , referred to above as a drum maintenance unit (DMU), applies release agent to the surface 30 of the image receiving member 34 . Referring to FIGS. 2 and 3 , the DMU 100 includes a housing 104 , a reservoir 108 , an applicator 110 , a reclaim area 114 , a pump 118 , a metering blade 120 , a cleaning blade 124 , a sump 128 , a filter 130 , a sump pump 134 , a positioning system 140 , and a memory 154 . In some embodiments, the DMU varies in some aspects from the one described and shown in the accompanying figures. For example, in some embodiments, the metering blade is also used as the cleaning blade. The DMU housing 104 is formed of a material, such as molded plastic, that is compatible with the release agent used in the printer 10 and that is capable of withstanding the environment within the housing 11 of the printer 10 during operational use of the printer. The reservoir 108 is positioned within the housing and is configured to hold a supply of release agent 112 . A vent tube or conduit 106 fluidly connects the interior of the reservoir 108 to atmosphere to relieve any positive or negative pressure developed in the reservoir. The vent tube includes a solenoid valve 116 that is normally closed to prevent any oil leaks during shipping and customer handling. The solenoid valve 116 is opened as oil is being pumped into and out of the oil reservoir to allow the reservoir to vent to atmospheric pressure. In some embodiments, the reservoir 108 is equipped with a pressure sensor 164 , such as a pressure transducer, which is configured to directly or indirectly detect or measure the pressure in reservoir 108 . As discussed below, the pressure sensor 164 may be used after a maintenance cycle is performed to determine a change in pressure in the reservoir as a result of pumping release agent to or from the reservoir. The change in pressure may then be used to determine a time period during which the solenoid valve 106 remains open after pumping has been completed to return the pressure to ambient. The applicator 110 is configured to apply the release agent 112 to the transfer surface 30 after the release agent is pumped from the reservoir 108 by the pump 118 . In the embodiment of FIG. 2 , the applicator 110 comprises a roller formed of an absorbent material, such as extruded polyurethane foam. In other embodiments, the applicator 110 is provided in a number of other shapes, forms, and/or materials. Each of these variations enable release agent from the reservoir 108 to be supplied to the reclaim area 114 where the applicator 110 absorbs the release agent and applies it to the surface 30 . For example, in other embodiments, the applicator 110 is comprised of a blotter or pad formed of an absorbent low-friction material that is pressed against the transfer surface 30 to apply release agent. To facilitate saturation of the roller 110 with the release agent, the roller 110 is positioned over a reclaim area 114 in the form of a tub or trough, referred to herein as a reclaim trough. A pump 118 moves release agent from the reservoir through a conduit 119 , or other suitable flow path, to the reclaim trough 114 . In one embodiment, the pump 118 comprises a peristaltic pump, although any suitable type of fluid pump or fluid transport system may be used. In the embodiment of FIG. 2 , the reclaim trough 114 has a bottom surface that follows the cylindrical profile of the lower portion of the roller 110 . The roller 110 is positioned with respect to the reclaim trough 114 to partially submerge the roller in release agent. In some embodiments, the bottom surface of the trough includes surface features (not shown), such as chevrons, that protrude from the surface and are shaped or angled to direct oil from the outer edges of the roller toward the center. The metering blade 120 is positioned close to the drum 34 and is configured to move into and out of contact with the surface 30 of the drum 34 . When the blade 120 contacts the surface 30 , the angle of attack of the blade enables the blade to spread the release agent applied to the surface 30 by the roller 110 to a uniform thickness. The metering blade 120 may be formed of an elastomeric material, such as urethane, supported on an elongated metal support bracket 122 . The metering blade 120 helps ensure that a uniform thickness of the release agent is present across the width of the surface 30 . In addition, the metering blade 120 is positioned above the reclaim trough 114 to divert excess oil metered from the surface 30 by blade 120 back into the reclaim trough 114 . The DMU 100 also includes a cleaning blade 124 that is positioned close to the drum 34 and is configured to move into and out of contact with the surface 30 of the drum 34 . When the blade 124 contacts the surface 30 of the drum 34 , the angle of attack of the blade enables the blade to scrape release agent and debris, such as paper fibers, residual ink and the like, from the surface 30 prior to a fresh application of release agent by roller 110 . In particular, after an ink image is fixed onto a print media, the portion of the drum upon which the image was formed is contacted by the cleaning blade 124 . Similar to the metering blade 120 , the cleaning blade 124 may be formed of an elastomeric material, such as urethane, supported on an elongated metal support bracket 126 . The cleaning blade 124 is positioned above the sump 128 to enable oil and debris scraped off of the surface 30 to be directed to the sump 128 . The sump 128 comprises a receptacle or compartment positioned to capture excess release agent delivered to the reclaim trough 114 , as well as release agent, dust, dried ink, and other debris diverted from the transfer surface 30 . The sump 128 is fluidly connected to the reservoir 108 by a conduit 135 . The sump pump 134 is configured to move release agent from the sump 128 through the conduit 135 to the reservoir 108 . A filter 130 is positioned in the conduit 135 to clean ink, oil, and debris that must pass through the filter before entering the reservoir 108 . In one embodiment, the sump pump 134 comprises a peristaltic pump although any suitable device may be used that moves release agent to be pumped to the reservoir from the sump 128 . In the embodiment of FIGS. 1 and 2 , the DMU 100 is implemented as a customer replaceable unit (CRU). As used herein, a CRU is a self-contained, modular unit that enables all or most of the components of the CRU to be inserted into and removed from a printer as a single unit. When implemented as a CRU, the components of the DMU, such as the housing 104 , reservoir 108 , release agent supply 112 , applicator 110 , and blades 120 , 124 are configured in a modular form capable of being inserted into and removed from the housing 11 of the printer 10 as single component. As depicted in FIG. 1 , the printer 10 includes a docking space or area 90 (shown schematically as a dotted line in FIG. 1 ) in the housing 11 that is configured to receive the DMU 100 . The printer 10 and/or the DMU housing 104 is provided with suitable attachment features (not shown), such as fastening mechanisms, latches, positioning guide features, and the like, to enable the correct placement and installation of the DMU 100 within the housing 11 . In other embodiments, the DMU may be a single field replaceable unit (FRU) or a collection of FRUs. As a CRU, the DMU 100 has an expected lifetime, or useful life, that corresponds to the amount of oil loaded in the DMU reservoir 108 . In the exemplary embodiment, the useful life may be between approximately 300,000 and 500,000 prints depending on factors such as oil usage and the amount of oil in the reservoir. When the DMU has reached the end of its useful life, for example, when the unit is out of release agent, the DMU may be removed from its location or slot in the imaging device and replaced with a new DMU. The DMU 100 includes a positioning system 140 ( FIG. 2 ) that enables the applicator 110 , metering blade 120 , and cleaning blade 124 to be selectively moved into and out of engagement with the surface 30 once the DMU is inserted into the housing. For example, the positioning system in one embodiment includes a moveable member that interacts with a cam in the housing 11 of the printing printer 10 . In the embodiment of FIG. 2 , the positioning system 140 includes a separate positioning mechanism 144 , 148 , and 150 , such as a cam follower, for each of the applicator 110 , metering blade 120 , and cleaning blade 124 , respectively. Each positioning system enables the component operatively connected to the positioning system to be moved into and out of engagement with the transfer surface 30 independently. The positioning mechanisms of the positioning system are configured to enable the applicator 110 , metering blade 120 , and cleaning blade 124 to be selectively and independently moved between a disengaged position ( FIG. 3 ) spaced apart from the surface 30 and an engaged position ( FIG. 2 ) in contact with the transfer surface 30 . In an alternative embodiment, the positioning mechanism 140 is configured so the DMU is moved between an engaged position and a disengaged position with respect to the transfer surface as a unit. Referring again to FIG. 2 , the DMU 100 includes a memory device 154 , such as an EEPROM, for storing operational values and other information pertaining to the DMU 100 , including data and operational information pertaining to the gel-based life-sensing process for use by the control system. The memory includes a plurality of memory locations for storing information pertaining to the operation of the DMU, such as the initial mass of release agent stored in the reservoir, the estimated current mass of release agent in the reservoir, the total number of prints performed by the DMU, the number of prints that are simplex prints, the number of prints that are duplex, the total media area of the prints, and the total media area that has been covered with ink. In one embodiment, the memory 154 is installed on a circuit board 158 . The circuit board 158 includes a suitable connector 160 configured to electrically connect the circuit board 158 including memory 154 to the printer control system 68 when the DMU 100 is installed in the housing 11 . Once the DMU 100 is inserted into the printer 10 and the memory 154 is connected to the controller 70 , the control system 68 selectively accesses the memory 154 to retrieve the operational values and selectively write operational values to the memory 154 to update the values during use. In this manner, DMU performance and life expectancy are tracked. In addition, various controllable components of the DMU 100 , such as the solenoid valve 116 , delivery pump 118 , sump pump 134 , pressure sensor 164 , and the positioning mechanisms 144 , 148 , and 150 of the positioning system 140 are each operatively connected to the circuit board 158 so the control system 68 can operate these components. The control system operates the DMU to perform a DM cycle for each page of each print job performed by the printer 10 . A standard, or full speed, DM cycle is performed for most pages of a print job. Typically, priority is placed on print speed; therefore, a DM cycle is nested within the print process to minimize overhead, for example, non-imaging and transfixing time, and maximize print speed. Although the DM system is optimized to reduce oil consumption at full print speed, oil consumption can be further reduced when the DM cycle is decoupled from the printing process. This is achieved using the slow auto DM cycle. A flowchart depicting a simplified version of a standard DM cycle is illustrated in FIG. 4 . During a standard DM cycle, the drum is rotated at a first velocity during ink image formation, which in one embodiment is approximately 1200-2000 mm/s (block 400 ). As the drum is rotated at the first velocity, the control system operates the positioning system 140 to actuate the positioning mechanism 148 to move the metering blade 120 into engagement with the surface of the drum (block 404 ). Similarly, the control system operates the positioning system 140 to actuate the positioning mechanism 144 to move the applicator into contact with the surface 30 to apply release agent to the drum surface (block 408 ). The metering blade and applicator remain in engagement with the drum surface for a predetermined distance. The velocity of drum rotation is changed from the first velocity to a velocity useful for transfixing the ink image onto a media sheet (block 410 ). After the predetermined distance, the control system operates the positioning system 140 and positioning mechanisms 148 and 144 to disengage the applicator from the surface of the drum (block 414 ). After a second predetermined distance, the metering blade is disengaged from the surface of the drum (block 418 ). The predetermined distance for the applicator engagement is selected with reference to the circumference of the drum. The predetermined distance for engagement of the metering blade is typically equal to or longer than the predetermined engagement distance for the applicator. The maximum metering blade wiping distance is typically chosen so that it does not slow down printing. To reduce the amount of release agent that is removed from the DMU over time, the control system 68 of the printer 10 is configured to operate the DMU and the drum with a Slow Auto DM cycle. A flowchart depicting a Slow Auto DM cycle is depicted in FIG. 5A . In a Slow Auto DM cycle, the drum is rotated at a velocity that is less than the first (imaging) velocity and transfixing velocity (block 500 ). A graph showing the timing sequence for the Slow Auto DM cycle is depicted in FIG. 5B . In one embodiment, the reduced drum velocity is approximately 200-500 mm/s. With the drum rotating at the reduced velocity, the control system operates the positioning system 140 and the positioning mechanism 144 to move the metering blade into engagement with the surface of the drum (block 504 ). The control system also operates the positioning system 140 and the positioning mechanism 148 to move the applicator in contact with the drum (block 508 ). The metering blade and applicator remain in engagement with the surface of the drum for a predetermined distance that corresponds to approximately one full revolution of the drum. After the predetermined distance has been traveled, the control system operates the positioning system to disengage the applicator from the drum surface (block 510 ) while the metering blade remains in contact with the drum surface. Immediately after the applicator is moved away from the drum surface, the drum is accelerated to a higher drum velocity with only the blade engaged with the drum (block 514 ). In one embodiment, the higher drum velocity corresponds substantially to one or both of the first and transfixing velocities, e.g., approximately 1200-2000 mm/s. When the drum reaches the higher drum velocity, the metering blade is disengaged from the drum surface (block 518 ). Disengaging the metering blade after the drum velocity reaches the higher velocity helps reduce any oil bar that may form after the metering blade lifts away from the drum surface. After the metering blade is disengaged, the velocity of the drum is reduced from the higher velocity to the reduced drum velocity used at the initiation of the Slow Auto DM cycle, e.g., the 200-300 mm/s (block 520 ). In some embodiments, the final drum velocity is reduced to zero or to a velocity conducive to maintaining a uniform drum temperature gradient while the printer waits for the next print job. Thereafter, when the next print job is received after performing the Slow Auto DM cycle, the control system may optionally operate the DMU and drum to perform a non-standard DM cycle in which only the metering blade engages the image receiving member or no DM cycle is performed for the first page of the print job (block 524 ). The optional blade only DM cycle enables the next print to begin imaging as fast as possible. If the next image cannot be placed over the release agent smear, a blade only DM cycle preceding the next image speeds up the first page out since the drum does not need to move to a position to avoid the oil smear. A Slow Auto DM cycle is performed following the completion of each print job not having any other fully ripped print jobs following in the print job queue. A Slow Auto DM cycle may also be performed when the printer 10 is started from a powered down state or when the device transitions to a ready state from a standby state or suspended operations state. Once the Slow Auto DM cycle has been performed, a print cycle in which no DM cycle is performed may begin as soon as a print job is received in the print job queue. In one embodiment, after a Slow Auto DM cycle has been performed, a print cycle is performed without a DM cycle once a print job is received. In this embodiment, the amount of time required to generate the first page of these print jobs is reduced because no DM cycle is performed. In addition, the first print of a print job may be generated with less noise because the sound generated by release agent application and metering is avoided. In another embodiment, after a Slow Auto DM cycle has been performed, a DM cycle in which only the metering blade engages the image receiving member is performed for the first print cycle of the next print job received in the print job queue. During this blade only DM cycle, the control system operates the positioning system to move the metering blade into engagement with the surface of the drum without operating the positioning system to move the applicator into engagement with the drum surface. In either case, after a Slow Auto DM cycle has been performed, release agent is not deposited onto the surface of the drum for the first page of a next print job received when the printer 10 is in an idle state, also referred to as the first page out (FPO). The absence of an applicator operation results in lower release agent consumption by the first page of the print job or the first and second page of a print job if two ink images are printed at a time on the drum. Because most print jobs have a low number of pages, e.g., 1-3, this reduction in release agent consumption for the first pages of some print jobs can significantly reduce overall release agent consumption and thus increase the life of the release agent supply, and, consequently, the DMU. Testing has shown that the slow auto DM cycle reduces oil consumption of a solid fill page by approximately 40%. Simplex image transfer efficiency, also known as pixel drop out, duplex image transfer efficiency, and image gloss are all significantly reduced for pages that are preceded by the slow auto DM cycle. A flowchart of a print process that incorporates the Slow Auto DM cycle is shown in FIG. 6 . As depicted, at the end of each print job (block 600 ), the printer queue is checked to detect whether any print jobs are waiting to be performed (block 604 ). If no fully ripped print job is in the job queue, a check is made to determine whether the Slow Auto DM cycle is enabled (block 608 ). A similar check is made when the device is being started from a powered down state or when the device is transitioning to a ready state from a standby state or suspended operations state (block 606 ). When the Slow Auto DM cycle is enabled, a further check is made to determine whether the previous DM cycle was a standard DM cycle or a Slow Auto DM cycle (block 610 ). In one embodiment, when the previous DM cycle was a standard DM cycle or no DM cycle was performed, the Slow Auto DM cycle is performed only after the device is in an idle state for a predetermined time period. The control system is configured to monitor the idle time of the imaging device. The idle time refers to the time elapsed from the end of the previous print job while no jobs are waiting in the queue. The idle time is compared to a predetermined idle time, or wait, threshold value (block 614 ). If the idle time is greater than the wait threshold value, a Slow Auto DM cycle is performed (block 618 ). In one embodiment, the threshold value is one second. If the printer 10 remains in an idle state for a prolonged duration after a Slow Auto DM cycle has been performed prior to receiving a print job, another Slow Auto DM cycle may be performed. For example, in one embodiment, if the previous DM cycle was a Slow Auto DM cycle, the control system 68 determines whether an elapsed time since the previous Slow Auto DM cycle has exceeded a predetermined threshold (block 620 ). That is, the control system 68 monitors the amount of time that has elapsed since the Slow Auto DM cycle was performed and compares the elapsed time to a predetermined threshold time value. If the elapsed time is greater than the threshold value, a Slow Auto DM cycle is performed (block 618 ). The predetermined threshold time value may be any suitable value and, in one embodiment, is set to infinity and, in another embodiment, the predetermined threshold time value is approximately 1 hour. If the elapsed time since the previous Slow Auto DM cycle does not exceed the threshold value, a Slow Auto DM cycle is not performed and the control system waits for the next print job to be received in the queue (block 624 ). This time threshold value helps avoid issues, such as transfer efficiency reduction, caused by oil evaporation or debris build-up on the drum surface. When a ripped print job is detected in the queue, the control system checks to determine whether the last performed DM cycle was a standard DM cycle or a Slow Auto DM cycle (block 628 ). If the previous DM cycle was a standard DM cycle, a standard DM cycle is performed for the detected print job (block 630 ). If the previous DM cycle was a Slow Auto DM cycle, the control system determines whether a blade only DM cycle has been enabled (block 634 ). If the blade only DM cycle is not enabled, a print cycle is performed that does not include a DM cycle (block 638 ). If a blade only DM cycle is enabled, a print cycle is performed with a blade only DM cycle (block 640 ). Control then returns to block 600 . For certain types of images, the lower release agent deposition for the slow auto DM cycle may not be adequate for ink image transfer and results in paper path smudging. For example, ink images that have a high coverage level typically have more ink pixels to transfer to print media than images with low coverage, and therefore may have an increased risk of smudging as the media moves along the media path. To reduce the risk of these types of defects, the control system 68 is configured to perform a standard DM cycle rather than a Slow Auto DM cycle based on the coverage level and/or image composition of the image to be printed. As mentioned above, the control system 68 is configured to parse image data to determine relevant print characteristics including the coverage level. In one embodiment, if the previously performed DM cycle was a Slow Auto DM cycle, the control system 68 is configured to compare the coverage level of a next print in a print job to a predetermined coverage level threshold value (block 632 ). If the coverage level of the print is greater than the coverage level threshold value, a standard DM cycle is performed for the print regardless of whether a previous Slow Auto DM cycle has been performed. In one embodiment, the coverage level threshold value is set to infinity. In addition to the speed of the drum, the amount of release agent that is deposited onto the drum during a DM cycle is also a function of metering blade wear. As wear of the blade increases, the amount of release agent that is metered onto the drum by the blade increases. For example, a metering blade may initially meter release agent onto the surface of the drum at approximately 3-4 mg/print. In some embodiments, this amount increases to approximately 8-9 mg/print after 50,000-100,000 prints have been performed. Therefore, very new metering blades sometimes provide too little oil during a slow auto DM cycle and image smudge defects may occur. Accordingly, in some embodiments the control system 68 is configured to begin utilizing the Slow Auto DM cycle after the metering blade has been used for a predetermined number of release agent applications. In one embodiment, the control system 68 maintains a count of the number of prints executed by the metering blade of the DMU and enables the Slow Auto DM cycle in response to the count reaching a predetermined print count value (block 609 ). The predetermined print count value may be any suitable number of prints. In one embodiment, the control system 68 is configured to enable the Slow Auto DM cycle after the release agent application system has been used to apply release agent for 20,000 prints. It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems, applications or methods. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

In a method of operating a printer, a release agent application system is operated to conserve release agent. The method of operation rotates the image receiving member that receives the release agent at a slower speed to reduce the amount of release agent applied to the image receiving member at select times. Thus, the release agent supply in the release agent application system lasts longer. For every page that is preceded by this method of image receiving member preparation, image gloss is increased and simplex and duplex image transfer efficiency is improved.

REFERENCE TO CROSS-RELATED APPLICATION [0001] This application is a Continuation-in-Part of U.S. patent application Ser. No. 12/343,464 filed on Dec. 23, 2008. [0002] This application claims priority benefits from U.S. patent application Ser. No. 12/343,464 filed on Dec. 23, 2008, which claims priority benefits from U.S. Provisional Patent Application No. 61/019,301, filed on Jan. 7, 2008, herein incorporated by reference in its entirety. FIELD OF THE INVENTION [0003] The present invention relates to an apparatus for transferring electrical power from a source plane to a receiving device placed in various orientations on this plane. BACKGROUND OF THE INVENTION [0004] Many of today's electronic devices are portable and some of them are even equipped with rechargeable batteries. [0005] If a battery less electronic device is used, it must be connected to a power supply, i.e. 110V/220V AC power outlet. [0006] When an electronic device equipped with rechargeable batteries is being used, the operating time of the device is limited to the available charge provided by at least one rechargeable battery. After the depletion of the batteries, the device must be connected to a power supply, i.e. 110V/220V AC power outlet in order to continue to operate and to recharge the batteries in the device. [0007] There are a number of problems associated with conventional means of powering or charging these devices: [0008] The devices have to be plugged into mains 110V/220V AC power outlet and hence if several are used together, they take up space in plug strips and create a messy and confusing tangle of wires. [0009] The locations of the power outlets are fixed and the number of outlets is usually limited. [0010] U.S. Pat. No. 3,521,216, (1970), which is incorporated by reference for all purposes as if fully set forth herein, taught the use of plug and socket assembly incorporating magnetic means for attracting and holding a plug in a socket. [0011] There is thus a widely recognized need for, and it would be highly advantageous to have a power outlet plug and socket that do not require any alignment at all. [0012] The prior art does not teach or suggest such a tool. SUMMARY OF THE INVENTION [0013] An apparatus for transferring electrical power from a source plane, to one receiving device or to a plurality of receiving devices placed in various orientations on this source plane according to the present invention can overcome the described limitations. [0014] The apparatus includes a planar stationary unit set and at least one mobile unit set. [0015] According to one embodiment the planar stationary unit set includes conductive plates embedded in the form of a grid in a non-conductive matrix. [0016] An example for the matrix material could be plastic but the matrix could be made of any material that is non-conductive. [0017] An example for the conductive plates embedded in the matrix material could be copper, but the conductive plates embedded in the matrix could be made of any material that is conductive. [0018] Each of the plates is connected to a power grid through a switch that is normally open. i.e., there is no voltage on the plates. [0019] Half of the plates are connected to the phase port of the electrical power grid and the other half are connected to the zero port of the electrical power grid. [0020] The port names used hereinafter are symbolic only and are not intended to limit the application of this invention to a specific type of electrical current. The present invention may also be used with a positive port and a negative port as used in direct current (DC) power supplies. [0021] In the case of a two dimensional stationary unit set, the plates are arranged in grid formation so that the four nearest neighboring plates of each plate are connected to the opposite port as the port that the plate itself is connected to. [0022] All the switches of the phase port are connected to a signal-receiving device and they can be turned on if in their proximity there is a device that transmits a specific signal to the receiving device. [0023] This transmitting device can transmit the signal (or code) through any form of transmission such as magnetic transmission, electromagnetic transmission, electrostatic transmission (capacitance), radio frequency (RF) transmission etc. [0024] All of the switches of the zero port are connected to a signal-receiving device and they can be turned on if in their proximity there is a device that transmits a specific signal (or code) to the receiving device. [0025] This transmitting device can transmit the signal (or code) through any form of transmission such as magnetic transmission, electromagnetic transmission, electrostatic transmission (capacitance), radio frequency (RF) transmission etc. [0026] The phase port switch cannot be turned on by the same transmission that turns on the zero port switches and the zero port switches cannot be turned on by the same transmission that turns on the phase port switches. [0027] According to the above embodiment, a mobile unit set that is comprised of two large conductive plates is embedded in a planar and non-conductive frame. [0028] The plates in the mobile unit set are significantly bigger than the distances between the plates in the planar stationary unit set so that if placed on the planar stationary unit set, each of the two plates in the mobile unit set covers several plates embedded in the planar stationary unit set. [0029] The distance between the plates in the mobile unit set is greater than the largest dimension of the plates in the planar stationary unit set so that no plate in the planar stationary unit set can be in contact with both plates in the mobile unit set. [0030] The width of the non-conductive frame surrounding the conductive plates is grater than the largest dimension of the plates in the planar stationary unit set so that no plate in the planar stationary unit set can touch a plane and extend beyond the frame at the same time. This is required for safety reasons: it is not permissible that a live plate would be exposed; hence, the mobile unit set must cover it. [0031] Behind each plate in the mobile unit set there is a transmitting device as mentioned before. [0032] Each transmitting device in the mobile unit set is transmitting a different signal (or code). [0033] One transmitting device is transmitting the signal (or code) that causes the phase port switches to turn on. [0034] The opposite transmitting device is transmitting the signal (or code) that causes the zero port switches to turn on. [0035] The plate that has the transmitting device that is transmitting the signal (or code) that causes the phase port switches to turn on is called the “phase plate”. [0036] The plate that has the transmitting device that is transmitting the signal (or code) that causes the zero port switches to turn on is called the “zero plate”. [0037] Following is a summary of the stages of the method according to the present invention: [0038] When the mobile unit set is placed on the planar stationary unit, both its zero plate and the phase plate are in contact with plates that are connected to the phase port and with plates that are connected to the zero port in the stationary unit. [0039] Of the plates that are in contact with the phase plate, only the switches that are connected to the phase port are switched on and thus an electrical connection is established between the phase plate and the phase port through the live plates. [0040] Of the plates that are in contact with the zero plate, only the switches that are connected to the zero port are switched on and thus an electrical connection is established between the zero plate and the zero port through the live plates. [0041] When any other device or being touches the planar stationary unit, and is in contact with the plates, it is not in electrical contact with the phase port or the zero port because the switches between the plates and the phase and zero ports are not on, thus, the exposed plates in the stationary unit are not “live” and are safe to touch. [0042] According to the present invention there is provided an apparatus for transferring electrical power including: (a) at least one planar stationary unit set including: (i) a planar stationary unit phase assembly, having a predetermined maximum cross section width dimension d 1 ; (ii) a planar stationary unit zero assembly, having a predetermined maximum cross section width dimension d 3 ; and (iii) a planar stationary unit set body, wherein the planar stationary unit phase assembly and the planar stationary unit zero assembly being encased inside the planar stationary unit set body aside one another; and (b) at least one mobile unit set including: (i) a mobile unit phase assembly; and (ii) a mobile unit zero assembly; and (iii) a mobile unit set body, wherein the mobile unit phase assembly and the mobile unit zero assembly being encased inside the mobile unit set body, aside one another, and wherein the at least one mobile unit set has a mobile unit set body edge. [0043] According to further features in an embodiment of the present invention, each one of the mobile unit phase assembly including: a mobile unit zero assembly housing; a mobile unit assembly phase assembly contact element disposed on the mobile unit zero assembly housing; and a mobile unit phase assembly magnet mounted inside the mobile unit zero assembly housing, wherein the mobile unit phase assembly magnet has a mobile unit phase assembly magnet first magnetic pole and a mobile unit phase assembly magnet second magnetic pole, wherein the mobile unit phase assembly magnet second magnetic pole is closer to the mobile unit assembly phase assembly contact element than the mobile unit phase assembly magnet first magnetic pole, wherein each one of the mobile unit zero assembly including: a mobile unit zero assembly contact element disposed on the mobile unit zero assembly housing; and a mobile unit zero assembly magnet, wherein the mobile unit zero assembly magnet, has a mobile unit zero assembly magnet first magnetic pole, and a mobile unit zero assembly magnet second magnetic pole, wherein the mobile unit phase assembly magnet first magnetic pole is closer to the mobile unit zero assembly contact element then the mobile unit zero assembly magnet second magnetic pole. [0044] According to further features in an embodiment of the present invention, the planar stationary unit phase assembly is a magnetic switch phase assembly, wherein the magnetic switch phase assembly including: a magnetic switch phase assembly housing; a magnetic switch phase assembly housing end disk disposed on the magnetic switch phase assembly housing; a magnetic switch phase assembly contact element disposed on the magnetic switch phase assembly housing; a magnetic switch phase assembly shaft mounted inside the magnetic switch phase assembly housing; a magnetic switch phase assembly voltage element mounted on the magnetic switch phase assembly shaft, wherein there is a first gap between the magnetic switch phase assembly contact element and the magnetic switch phase assembly voltage element; a magnetic switch phase assembly magnet mounted on the magnetic switch phase assembly shaft; a magnetic switch phase assembly voltage element spring mounted inside the magnetic switch phase assembly housing, and between the magnetic switch phase assembly voltage element and the magnetic switch phase assembly housing end disk; and a magnetic switch phase assembly magnet spring mounted inside the magnetic switch phase assembly housing, and between the magnetic switch phase assembly magnet and the magnetic switch phase assembly housing end disk. [0045] According to further features in an embodiment of the present invention, the at least one planar stationary unit set further including: (v) a planar stationary unit ground element encased inside the planar stationary unit set body, and wherein the at least one mobile unit set further including: (v) a mobile unit ground element encased inside the planar stationary unit set body. [0046] According to another features in an embodiment of the present invention, the planar stationary unit phase assembly is an electromagnetic switch assembly, wherein the electromagnetic switch assembly including: an electromagnetic switch assembly housing; an electromagnetic switch assembly housing end disk disposed on the electromagnetic switch assembly housing; an electromagnetic switch assembly contact element disposed on the electromagnetic switch assembly housing; an electromagnetic switch assembly shaft mounted inside the electromagnetic switch assembly housing; an electromagnetic switch assembly voltage element mounted on the electromagnetic switch assembly shaft, wherein there is a second gap between the electromagnetic switch assembly contact element and the electromagnetic switch assembly voltage element; an electromagnetic switch assembly electromagnet core mounted on the electromagnetic switch assembly shaft; an electromagnetic switch assembly electromagnet coil mounted on the electromagnetic switch assembly shaft; an electromagnetic switch assembly voltage element spring mounted inside the electromagnetic switch assembly housing and between the electromagnetic switch assembly voltage element and the electromagnetic switch assembly housing end disk; and an electromagnetic switch assembly electromagnet spring mounted inside the electromagnetic switch assembly housing, and between the electromagnetic switch assembly electromagnet core and the electromagnetic switch assembly housing end disk. [0047] According to further features in an embodiment of the present invention, the at least one planar stationary unit set further including: (v) a planar stationary unit ground element encased inside the planar stationary unit set body, and wherein the at least one mobile unit set further including: (v) a mobile unit ground element encased inside the planar stationary unit set body. [0048] According to another features in an embodiment of the present invention, the planar stationary unit phase assembly is a cantilever version of a magnetic switch assembly, wherein the cantilever version of a magnetic switch assembly including: a cantilever version of a magnetic switch assembly housing; a cantilever version of a magnetic switch assembly contact element disposed on the cantilever version of a magnetic switch assembly housing; a cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring disposed on the cantilever version of a magnetic switch assembly housing inside the cantilever version of a magnetic switch assembly housing; and a cantilever version of a magnetic switch assembly magnet disposed on the cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring, wherein there is a third gap between the cantilever version of a magnetic switch assembly contact element and the cantilever version of a magnetic switch assembly magnet. [0049] According to further features in an embodiment of the present invention, the at least one planar stationary unit set further including: (v) a planar stationary unit ground element encased inside the planar stationary unit set body, and wherein the at least one mobile unit set further including: (v) a mobile unit ground element encased inside the planar stationary unit set body. [0050] According to another features in an embodiment of the present invention, the planar stationary unit phase assembly is a cantilever version of an electro-magnetic switch assembly, wherein the cantilever version of an electro-magnetic switch assembly including: a cantilever version of electro-magnetic switch assembly housing; a cantilever version of electro-magnetic switch assembly contact element disposed on the cantilever version of electro-magnetic switch assembly housing; a cantilever version of electro-magnetic switch assembly voltage element wire and assembly voltage element spring disposed on the cantilever version of electro-magnetic switch assembly housing inside the cantilever version of electro-magnetic switch assembly housing; a cantilever version of electro-magnetic switch assembly core disposed on the cantilever version of electro-magnetic switch assembly voltage element wire and assembly voltage element spring; and a cantilever version of electro-magnetic switch assembly electromagnet coil mounted around the cantilever version of electro-magnetic switch assembly core, wherein there is a fourth gap between the cantilever version of electro-magnetic switch assembly contact element and the cantilever version of electro-magnetic switch assembly core. [0051] According to further features in an embodiment of the present invention, the at least one planar stationary unit set further including: (v) a planar stationary unit ground element encased inside the planar stationary unit set body, and wherein the at least one mobile unit set further including: (v) a mobile unit ground element encased inside the planar stationary unit set body. [0052] According to another features in an embodiment of the present invention, there is a minimum predetermined distance d 4 between the mobile unit phase assembly and the mobile unit zero assembly, wherein there is a minimum predetermined distance d 2 from the mobile unit phase assembly, and from the mobile unit zero assembly to the mobile unit set body edge, wherein the distance d 4 is larger than the maximum cross section width dimension d 1 and is larger than the maximum cross section width dimension d 3 , and wherein the distance d 2 is larger than the maximum cross section width dimension d 1 and is larger than the maximum cross section width dimension d 3 . [0053] According to further features in an embodiment of the present invention, the planar stationary unit phase assembly is a magnetic switch phase assembly, wherein the magnetic switch phase assembly including: a magnetic switch phase assembly housing; a magnetic switch phase assembly housing end disk disposed on the magnetic switch phase assembly housing; a magnetic switch phase assembly contact element disposed on the magnetic switch phase assembly housing; a magnetic switch phase assembly shaft mounted inside the magnetic switch phase assembly housing; a magnetic switch phase assembly voltage element mounted on the magnetic switch phase assembly shaft, wherein there is a first gap between the magnetic switch phase assembly contact element and the magnetic switch phase assembly voltage element; a magnetic switch phase assembly magnet mounted on the magnetic switch phase assembly shaft; a magnetic switch phase assembly voltage element spring mounted inside the magnetic switch phase assembly housing, and between the magnetic switch phase assembly voltage element and the magnetic switch phase assembly housing end disk; and a magnetic switch phase assembly magnet spring mounted inside the magnetic switch phase assembly housing, and between the magnetic switch phase assembly magnet and the magnetic switch phase assembly housing end disk. [0054] According to further features in an embodiment of the present invention, the apparatus for transferring electrical power including: (c) a planar stationary unit grid body, wherein the planar stationary unit grid body, connects together a plurality of the at least one planar stationary unit set. [0055] According to still another features in an embodiment of the present invention, the planar stationary unit phase assembly is an electromagnetic switch assembly, wherein the electromagnetic switch assembly including: an electromagnetic switch assembly housing; an electromagnetic switch assembly housing end disk disposed on the electromagnetic switch assembly housing; an electromagnetic switch assembly contact element disposed on the electromagnetic switch assembly housing; an electromagnetic switch assembly shaft mounted inside the electromagnetic switch assembly housing; an electromagnetic switch assembly voltage element mounted on the electromagnetic switch assembly shaft, wherein there is a second gap between the electromagnetic switch assembly contact element and the electromagnetic switch assembly voltage element; an electromagnetic switch assembly electromagnet core mounted on the electromagnetic switch assembly shaft; an electromagnetic switch assembly electromagnet coil mounted on the electromagnetic switch assembly shaft; an electromagnetic switch assembly voltage element spring mounted inside the electromagnetic switch assembly housing and between the electromagnetic switch assembly voltage element and the electromagnetic switch assembly housing end disk; and an electromagnetic switch assembly electromagnet spring mounted inside the electromagnetic switch assembly housing, and between the electromagnetic switch assembly electromagnet core and the electromagnetic switch assembly housing end disk. [0056] According to further features in an embodiment of the present invention, the apparatus for transferring electrical power including: (c) a planar stationary unit grid body, wherein the planar stationary unit grid body, connects together a plurality of the at least one planar stationary unit set. [0057] According to another features in an embodiment of the present invention, the planar stationary unit phase assembly is a cantilever version of a magnetic switch assembly, wherein the cantilever version of a magnetic switch assembly including: a cantilever version of a magnetic switch assembly housing; a cantilever version of a magnetic switch assembly contact element disposed on the cantilever version of a magnetic switch assembly housing; a cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring disposed on the cantilever version of a magnetic switch assembly housing inside the cantilever version of a magnetic switch assembly housing; and a cantilever version of a magnetic switch assembly magnet disposed on the cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring, wherein there is a third gap between the cantilever version of a magnetic switch assembly contact element and the cantilever version of a magnetic switch assembly magnet. [0058] According to further features in an embodiment of the present invention, the apparatus for transferring electrical power including: (c) a planar stationary unit grid body, wherein the planar stationary unit grid body, connects together a plurality of the at least one planar stationary unit set. [0059] According to another features in an embodiment of the present invention, the planar stationary unit phase assembly is a cantilever version of an electro-magnetic switch assembly, wherein the cantilever version of an electro-magnetic switch assembly including: a cantilever version of electro-magnetic switch assembly housing a cantilever version of electro-magnetic switch assembly contact element disposed on the cantilever version of electro-magnetic switch assembly housing; a cantilever version of electro-magnetic switch assembly voltage element wire and assembly voltage element spring disposed on the cantilever version of electro-magnetic switch assembly housing inside the cantilever version of electro-magnetic switch assembly housing; a cantilever version of electro-magnetic switch assembly core disposed on the cantilever version of electro-magnetic switch assembly voltage element wire and assembly voltage element spring; and a cantilever version of electro-magnetic switch assembly electromagnet coil mounted around the cantilever version of electro-magnetic switch assembly core, wherein there is a fourth gap between the cantilever version of electro-magnetic switch assembly contact element and the cantilever version of electro-magnetic switch assembly core. [0060] According to further features in an embodiment of the present invention, the apparatus for transferring electrical power including: (c) a planar stationary unit grid body, wherein the planar stationary unit grid body, connects together a plurality of the at least one planar stationary unit set. BRIEF DESCRIPTION OF THE DRAWINGS [0061] The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: [0062] FIG. 1 a of the prior art illustrates an exploded perspective view of a plug upon which the section plane 1 b - 1 b is marked, and socket assembly upon which the section plane 1 c - 1 c is marked, showing the plug disconnected from the socket according to U.S. Pat. No. 3,521,216. [0063] FIG. 1 b is a cross section of the plug taken in the direction of the arrows 1 b - 1 b of FIG. 1 a. [0064] FIG. 1 c is a cross section of the socket taken in the direction of the arrows 1 c - 1 c of FIG. 1 a. [0065] FIG. 2 a is a side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly, according to the present invention. [0066] FIG. 2 b is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly, according to the present invention. [0067] FIG. 2 c is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly, according to the present invention. [0068] FIG. 2 d is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly, according to the present invention. [0069] FIG. 3 a is a perspective view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly voltage element, according to the present invention, upon which the section plane 3 b - 3 b is marked. [0070] FIG. 3 b is a cross sectional side view 3 b - 3 b schematic illustration of an exemplary, illustrative embodiment of the magnetic switch phase assembly voltage element, according to the present invention. [0071] FIG. 4 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an electromagnetic switch assembly, according to the present invention. [0072] FIG. 4 b is a side view schematic illustration of an exemplary, illustrative embodiment of an electromagnetic switch assembly electromagnet, according to the present invention. [0073] FIG. 5 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a cantilever version of a magnetic switch assembly, according to the present invention. [0074] FIG. 5 b is a top view schematic illustration of an exemplary, illustrative embodiment of a cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring, according to the present invention. [0075] FIG. 6 is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a cantilever version of an electro-magnetic switch assembly, according to the present invention. [0076] FIG. 7 a is a front view schematic illustration of an exemplary, illustrative embodiment of planar stationary unit set, according to the present invention. [0077] FIG. 7 b is a front view schematic illustration of an exemplary, illustrative embodiment of planar stationary unit set, according to the present invention. [0078] FIG. 8 is a side view schematic illustration of an exemplary, illustrative embodiment of planar stationary unit set, embedded within the non-conductive matrix, such as a building wall, according to the present invention. [0079] FIG. 9 a is a top view schematic illustration of an exemplary, illustrative embodiment of the planar stationary unit set, including several planar stationary unit phase switch assemblies, planar stationary unit ground elements, and planar stationary unit zero assemblies, arranged in a matrix as described in the figure, where round cross section are used, according to the present invention. [0080] FIG. 9 b is a top view schematic illustration of an exemplary, illustrative embodiment of the planar stationary unit set, including several planar stationary unit phase switch assemblies, planar stationary unit ground elements, and planar stationary unit zero assemblies, arranged in a matrix as described in the figure, where square cross section are used, according to the present invention. [0081] FIG. 10 a is a partial cut-away isometric view schematic illustration of an exemplary, illustrative embodiment of a mobile unit phase assembly according to the present invention. [0082] FIG. 10 b is a cross sectional side view schematic illustration of an exemplary, illustrative embodiment of a mobile unit phase assembly, according to the present invention. [0083] FIG. 11 a is a partial cut-away side view schematic illustration of an exemplary illustrative embodiment of a planar stationary unit set according to the present invention. [0084] FIG. 11 b is a partial cut-away view schematic illustration of an exemplary, illustrative embodiment of a planar stationary unit set, according to the present invention. [0085] FIG. 12 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a mobile unit set, according to the present invention. [0086] FIG. 12 b is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a mobile unit set, according to the present invention. [0087] FIG. 13 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power, according to the present invention. [0088] FIG. 13 b is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power, according to the present invention. [0089] FIG. 13 c is a partial cut-away view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power, according to the present invention. [0090] FIG. 13 d is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power, according to the present invention. [0091] FIG. 13 e is a partial cut-away view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power according to the present invention. [0092] FIG. 13 f is a front view schematic illustration of an exemplary, illustrative embodiment of mobile unit set, according to the present invention. [0093] FIG. 14 a is a schematic diagram of a means of supplying DC voltage to at least one planar stationary unit set, according to the present invention. [0094] FIG. 14 b is a schematic diagram of supplying DC voltage from a mobile unit set to a receiving portable electronic device's power plug, according to the present invention, using a mobile unit voltage regulator. [0095] FIG. 15 is a top view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power, according to the present invention; it also depicts several dimensions crucial to the safety of the apparatus for transferring electrical power, according to the present invention. DETAILED DESCRIPTION OF EMBODIMENTS [0096] The present invention is an apparatus for transferring electrical power from a source plane to a receiving device placed in various orientations on this plane. [0097] The principles and operation of the apparatus for transferring electrical power from a source plane to a receiving device placed in various orientations on this plane according to the present invention may be better understood with reference to the drawings and the accompanying description. [0098] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. [0099] Unless otherwise defined or explained, all 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. The materials, dimensions, methods, and examples provided herein are illustrative only and are not intended to be limiting. [0100] The following is a list of legend of the numbering of the application illustrations: 10 planar stationary unit phase assembly 10 m planar surface 10 n pipe 11 planar stationary unit zero assembly 12 planar stationary unit ground element 12 j planar stationary unit ground element wire 13 a planar stationary unit phase power supply 13 b planar stationary unit zero power supply 13 c planar stationary unit ground 20 mobile unit phase assembly 20 a mobile unit assembly phase assembly contact element 20 e mobile unit phase assembly magnet 20 h mobile unit phase assembly housing 20 i mobile unit phase assembly housing end disk 20 j mobile unit phase assembly wire 20 l mobile unit phase assembly symmetry axis 20 x mobile unit phase assembly magnet first magnetic pole 20 y mobile unit phase assembly magnet second magnetic pole 21 mobile unit zero assembly 21 a mobile unit zero assembly contact element 21 e mobile unit zero assembly magnet 21 h mobile unit zero assembly housing 21 i mobile unit zero assembly housing end disk 21 j mobile unit zero assembly wire 21 l mobile unit zero assembly symmetry axis 21 x mobile unit zero assembly magnet first magnetic pole 21 y mobile unit zero assembly magnet second magnetic pole 22 mobile unit ground element 22 j mobile unit ground element wire 32 electromagnetic switch assembly 32 a electromagnetic switch assembly contact element 32 b electromagnetic switch assembly voltage element 32 c electromagnetic switch assembly shaft 32 f electromagnetic switch assembly electromagnet spring 32 g electromagnetic switch assembly voltage element spring 32 h electromagnetic switch assembly housing 32 i electromagnetic switch assembly housing end disk 32 j electromagnetic switch assembly voltage element wire 32 l electromagnetic switch assembly symmetry axis 32 p electromagnetic switch assembly electromagnet core 32 q electromagnetic switch assembly electromagnet coil 32 r electromagnetic switch assembly electromagnet coil first pin 32 s electromagnetic switch assembly electromagnet coil second pin 32 t electromagnetic switch assembly electromagnet 32 z second gap 34 cantilever version of a magnetic switch assembly 34 a cantilever version of a magnetic switch assembly contact element 34 e cantilever version of a magnetic switch assembly magnet 34 h cantilever version of a magnetic switch assembly housing 34 j cantilever version of a magnetic switch assembly wire 34 jg cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring 34 x cantilever version of a magnetic switch assembly magnet first magnetic pole 34 y cantilever version of a magnetic switch assembly magnet second magnetic pole 34 z third gap 35 cantilever version of an electro-magnetic switch assembly 35 a cantilever version of electro-magnetic switch assembly contact element 35 h cantilever version of electro-magnetic switch assembly housing 35 jg cantilever version of electro-magnetic switch assembly voltage element wire and assembly voltage element spring 35 p cantilever version of electro-magnetic switch assembly core 35 q cantilever version of electro-magnetic switch assembly electromagnet coil 35 r cantilever version of electro-magnetic switch assembly electromagnet coil first pin 35 s cantilever version of electro-magnetic switch assembly electromagnet coil second pin 35 z fourth gap 40 magnetic switch phase assembly 40 a magnetic switch phase assembly contact element 40 b magnetic switch phase assembly voltage element 40 ba magnetic switch phase assembly voltage element base 40 bb magnetic switch phase assembly voltage element wall 40 c magnetic switch phase assembly shaft 40 e magnetic switch phase assembly magnet 40 f magnetic switch phase assembly magnet spring 40 g magnetic switch phase assembly voltage element spring 40 h magnetic switch phase assembly housing 40 i magnetic switch phase assembly housing end disk 40 j magnetic switch phase wire 40 l magnetic switch phase assembly symmetry axis 40 m planar surface 40 n pipe 40 z first gap 40 x magnetic switch phase assembly magnet first magnetic pole 40 y magnetic switch phase assembly magnet second magnetic pole 41 magnetic switch zero assembly 41 a magnetic switch zero assembly contact element 41 b magnetic switch zero assembly voltage element 41 c magnetic switch zero assembly shaft 41 e magnetic switch zero assembly magnet 41 f magnetic switch zero assembly magnet spring 41 g magnetic switch zero assembly voltage element spring 41 h magnetic switch zero assembly housing 41 i magnetic switch zero assembly housing end disk 41 j magnetic switch zero wire 41 l magnetic switch zero assembly symmetry axis 41 x magnetic switch zero assembly magnet first magnetic pole 41 y magnetic switch zero assembly magnet second magnetic pole 60 non-conductive matrix 71 mains outlet plug 72 AC to DC converter 73 planar stationary unit voltage regulator 74 mobile unit voltage regulator 76 portable electronic device's power plug 100 apparatus for transferring electrical power 101 planar stationary unit set 101 a planar stationary unit set body 102 mobile unit set 102 a mobile unit set body 102 b mobile unit set body edge 201 planar stationary unit grid 201 a planar stationary unit grid body [0209] Referring now to the drawings, FIG. 2 a is a side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly 40 , according to the present invention. [0210] FIG. 2 b is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly 40 , according to the present invention. [0211] The figure depicts the elements comprising the magnetic switch phase assembly 40 , and the way they are arranged with regards to each other, while omitting the magnetic switch phase assembly voltage element spring 40 g, (not shown in the present illustration), and the magnetic switch phase wire 40 j, (not shown in the present illustration). [0212] The magnetic switch phase assembly 40 has a magnetic switch phase assembly housing 40 h, which is electrically non-conductive, a magnetic switch phase assembly contact element 40 a, designed to conduct electricity when in contact with a mobile unit phase assembly 20 , (not shown in the present illustration), and is located at one outer edge of the magnetic switch phase assembly 40 , a magnetic switch phase assembly shaft 40 c, which is electrically non-conductive, is located in the middle of the magnetic switch phase assembly housing 40 h, on which other elements may travel over, such as a magnetic switch phase assembly voltage element 40 b, receiving an electrical voltage by means of a magnetic switch phase wire 40 j, (not shown in the present illustration), and a magnetic switch phase assembly magnet 40 e, attached to a magnetic switch phase assembly magnet spring 40 f. The magnetic switch phase assembly 40 is sealed at the opposite end of the magnetic switch phase assembly contact element 40 a by a magnetic switch phase assembly housing end disk 40 i. [0213] FIG. 2 c is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly 40 , according to the present invention. [0214] This figure depicts the magnetic switch phase wire 40 j. In normal operation the magnetic switch phase assembly voltage element spring 40 g ensures that there is a first gap 40 z between the magnetic switch phase assembly contact element 40 a, and the magnetic switch phase assembly voltage element 40 b, such that there is no electrical contact between them. Should a suitable (and strong enough) magnetic force be applied to the magnetic switch phase assembly magnet 40 e and to the magnetic switch phase assembly voltage element 40 b, it will overcome the strength of the magnetic switch phase assembly magnet spring 40 f, and the magnetic switch phase assembly voltage element spring 40 g, creating a physical contact which enables an electrical current to flow between the magnetic switch phase assembly contact element 40 a, and the magnetic switch phase assembly voltage element 40 b. [0215] Magnetic switch phase wire 40 j can also be omitted, and the magnetic switch phase assembly voltage element spring 40 g can be used as an electrical conductor in its place. [0216] The magnetic switch phase assembly 40 can have a magnetic switch phase assembly symmetry axis 40 l. [0217] According to another embodiment of the present invention the magnetic switch phase assembly 40 includes no magnetic switch phase assembly magnet 40 e and a suitable stronger magnetic force is applied to the magnetic switch phase assembly voltage element 40 b, at the proper time. [0218] FIG. 2 d is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly 40 , according to the present invention. [0219] The illustration shows force F 1 which applies to the magnetic switch phase assembly voltage element 40 b, while so long as it is not over powered by an opposite force, there will be no contact between the magnetic switch phase assembly voltage element 40 b and magnetic switch phase assembly contact element 40 a, and force F 2 which applies to the magnetic switch phase assembly magnet 40 e, while only applying a stronger force in the opposite direction will enable movement of the magnetic switch phase assembly magnet 40 e in the direction of the magnetic switch phase assembly voltage element 40 b. [0220] Despite including the word “phase” in the magnetic switch phase assembly 40 and related components' names, it is to be understood that this is not to limit the use of the present invention to be used with alternating current type of electricity, but it can be used with other types of electricity, such as direct current. [0221] FIG. 3 a is a perspective view schematic illustration of an exemplary, illustrative embodiment of a magnetic switch phase assembly voltage element 40 b, according to the present invention, upon which the section plane 3 b - 3 b is marked. [0222] This figure depicts a possible structure of the magnetic switch phase assembly voltage element 40 b, which is shaped as a cylinder comprising of a magnetic switch phase assembly voltage element base 40 ba, and a magnetic switch phase assembly voltage element wall 40 bb, allowing for the best possible movement within the magnetic switch phase assembly housing 40 h. [0223] FIG. 3 b is a cross sectional side view 3 b - 3 b schematic illustration of an exemplary, illustrative embodiment of the magnetic switch phase assembly voltage element 40 b, according to the present invention. [0224] FIG. 4 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an electromagnetic switch assembly 32 , according to the present invention. [0225] The structure of the electromagnetic switch assembly 32 is mostly similar to the structure of magnetic switch phase assembly 40 , (not shown in the present illustration), other than one main difference. The electromagnetic switch assembly 32 has no magnetic switch phase assembly magnet 40 e, (not shown in the present illustration), but instead has an electromagnetic switch assembly electromagnet 32 t, which includes an electromagnetic switch assembly electromagnet core 32 p and an electromagnetic switch assembly electromagnet coil 32 q, whose ends have an electromagnetic switch assembly electromagnet coil first pin 32 r and an electromagnetic switch assembly electromagnet coil second pin 32 s. Also, instead of a magnetic switch phase wire 40 j, (not shown in the present illustration), there is an electromagnetic switch assembly voltage element wire 32 j. [0226] The electromagnet functions as a magnet and provides a magnetic force whose power and direction depends upon the electrical current conducted through the electromagnetic switch assembly electromagnet coil 32 q, when there is such a current. [0227] The electromagnetic switch assembly 32 also includes an electromagnetic switch assembly shaft 32 c, an electromagnetic switch assembly voltage element 32 b, an electromagnetic switch assembly contact element 32 a, an electromagnetic switch assembly voltage element spring 32 g, an electromagnetic switch assembly electromagnet spring 32 f, an electromagnetic switch assembly housing 32 h, and an electromagnetic switch assembly housing end disk 32 i. The electromagnetic switch assembly 32 can have an electromagnetic switch assembly symmetry axis 32 l. [0228] In normal operation the electromagnetic switch phase assembly voltage element spring 32 g ensures that there is a second gap 32 z between the electromagnetic switch phase assembly contact element 32 a, and the electromagnetic switch phase assembly voltage element 32 b, such that there is no electrical contact between them. [0229] FIG. 4 b is a side view schematic illustration of an exemplary, illustrative embodiment of an electromagnetic switch assembly electromagnet 32 t, according to the present invention. [0230] The electromagnetic switch assembly electromagnet 32 t contains an electromagnetic switch assembly electromagnet core 32 p surrounded by an electromagnetic switch assembly electromagnet coil 32 q which has an electromagnetic switch assembly electromagnet coil first pin 32 r and an electromagnetic switch assembly electromagnet coil second pin 32 s. Upon applying direct current through the electromagnetic switch assembly electromagnet coil 32 q, the electromagnetic switch assembly electromagnet core 32 p is magnetized in a specific polarity determined by the direction of the current flowing through the electromagnetic switch assembly electromagnet coil 32 q. [0231] FIG. 5 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a cantilever version of a magnetic switch assembly 34 , according to the present invention. [0232] In the cantilever version of the magnetic switch, the cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring 34 jg is used to conduct electricity from the cantilever version of a magnetic switch assembly wire 34 j to the cantilever version of a magnetic switch assembly contact element 34 a (when engaged) as well as to move the cantilever version of a magnetic switch assembly magnet 34 e away from the cantilever version of a magnetic switch assembly contact element 34 a when it is not engaged, and form a third gap 34 z. [0233] The cantilever version of a magnetic switch assembly magnet 34 e has a cantilever version of a magnetic switch assembly magnet first magnetic pole 34 x and a cantilever version of a magnetic switch assembly magnet second magnetic pole 34 y just as in the magnetic switch phase assembly 40 (not shown in the present figure). [0234] It is possible to affix the cantilever version of a magnetic switch assembly magnet 34 e in the opposite orientation to the one presented in the present figure, thereby creating a cantilever version of the magnetic switch zero assembly 41 (not shown in the present figure). [0235] The cantilever version of a magnetic switch 34 is enclosed in a cantilever version of a magnetic switch assembly housing 34 h. [0236] FIG. 5 b is a top view schematic illustration of an exemplary, illustrative embodiment of a cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring 34 jg, according to the present invention. [0237] The cantilever version of a magnetic switch assembly voltage element wire and assembly voltage element spring 34 jg is made of a flexible material that can bend towards the cantilever version of a magnetic switch assembly contact element 34 a and back during normal operation. [0238] FIG. 6 is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a cantilever version of an electro-magnetic switch assembly, according to the present invention 35 . [0239] The operating concept of cantilever version of an electro-magnetic switch assembly 35 is the same as in the cantilever version of a magnetic switch 34 , (not shown in the present illustration). [0240] However, in this instance, the cantilever version of a magnetic switch assembly magnet 34 e, (not shown in the present illustration), is replaced by a cantilever version of electro-magnetic switch assembly electromagnet coil 35 q (which has a cantilever version of electro-magnetic switch assembly electromagnet coil first pin 35 r and cantilever version of electro-magnetic switch assembly electromagnet coil second pin 35 s ) and a cantilever version of electro-magnetic switch assembly core 35 p. [0241] The cantilever version of an electro-magnetic switch assembly 35 is enclosed in the cantilever version of electro-magnetic switch assembly housing 35 h and includes a cantilever version of electro-magnetic switch assembly contact element 35 a. [0242] FIG. 7 a is a front view schematic illustration of an exemplary, illustrative embodiment of planar stationary unit set 101 , according to the present invention. [0243] The planar stationary unit set 101 according to the illustrative embodiment of the present illustration includes a planar stationary unit phase assembly 10 , and a planar stationary unit zero assembly 11 which are both encased in a planar stationary unit set body 101 a. [0244] In the case described in the figure, the planar stationary unit phase assembly 10 , and the planar stationary unit zero assembly 11 cross sections are circular, but other shapes are possible as well. [0245] FIG. 7 b is a front view schematic illustration of an exemplary, illustrative embodiment of planar stationary unit set 101 , according to the present invention. [0246] The planar stationary unit set 101 according to the illustrative embodiment of the present illustration includes a planar stationary unit phase assembly 10 , a planar stationary unit zero assembly 11 and a planar stationary unit ground element 12 , all the three are enclosed in a planar stationary unit set body 101 a. [0247] In the case described in the figure, the planar stationary unit phase assembly 10 , the planar stationary unit ground element 12 , and the planar stationary unit zero assembly 11 cross sections are circular, but other shapes are possible as well. [0248] FIG. 8 is a side view schematic illustration of an exemplary, illustrative embodiment of planar stationary unit set 101 , embedded within the non-conductive matrix 60 , such as a building wall, according to the present invention. [0249] Pipe 10 n may serve for securing and protecting the electrical wires connecting the power supply grid to the planar stationary unit set 101 . The planar stationary unit set 101 have a planar surface 10 m. [0250] FIG. 9 a is a top view schematic illustration of an exemplary, illustrative embodiment of the planar stationary unit set 101 , including several planar stationary unit phase assemblies 10 , several planar stationary unit ground elements 12 , and several planar stationary unit zero assemblies 11 , arranged in a matrix as described in the figure, with round cross section are used, according to the present invention. [0251] In this figure, it is possible to see the electrical connections of the different phase and zero assemblies to their corresponding power supplies. The planar stationary unit phase assemblies 10 are connected to a planar stationary unit phase power supply 13 a, the planar stationary unit ground elements 12 are connected to a planar stationary unit ground 13 c and the planar stationary unit zero assemblies 11 are connected to a planar stationary unit zero power supply 13 b. [0252] FIG. 9 b is a top view schematic illustration of an exemplary, illustrative embodiment of the planar stationary unit set 101 , including several planar stationary unit phase assemblies 10 , several planar stationary unit ground elements 12 , and several planar stationary unit zero assemblies 11 , arranged in a matrix as described in the figure, with square cross section are used, according to the present invention. [0253] In this figure, it is possible to see the electrical connections of the different phase and zero assemblies to their corresponding power supplies. The planar stationary unit phase assemblies 10 are connected to the planar stationary unit phase power supply 13 a, the planar stationary unit ground elements 12 are connected to the planar stationary unit ground 13 c and the planar stationary unit zero assemblies 11 are connected to the planar stationary unit zero power supply 13 b. [0254] FIG. 10 a is a partial cut-away isometric view schematic illustration of an exemplary, illustrative embodiment of a mobile unit phase assembly 20 according to the present invention. [0255] FIG. 10 b is a cross sectional side view schematic illustration of an exemplary, illustrative embodiment of a mobile unit phase assembly 20 , according to the present invention. [0256] The mobile unit phase assembly 20 can have a mobile unit phase assembly symmetry axis 201 . [0257] A mobile unit phase assembly housing 20 h including inside of it, a mobile unit phase assembly magnet 20 e which has a mobile unit phase assembly magnet first magnetic pole 20 x, and a mobile unit phase assembly magnet second magnetic pole 20 y and is sealed in the back by a mobile unit phase assembly housing end disk 20 i and in the front by a mobile unit assembly phase assembly contact element 20 a, used to receive an electrical current from a planar stationary unit phase assembly 10 , (not shown in the present illustration), to which a mobile unit phase assembly wire 20 j is connected. [0258] FIG. 11 a is a partial cut-away side view schematic illustration of an exemplary illustrative embodiment of a planar stationary unit set 101 according to the present invention. [0259] The planar stationary unit set 101 includes a planar stationary unit set body 101 a, a magnetic switch phase assembly 40 , which is connected to a magnetic switch phase wire 40 j and a magnetic switch zero assembly 41 , which is connected to a magnetic switch zero wire 41 j. The magnetic switch phase assembly 40 and the magnetic switch zero assembly 41 are located in a single plane and encased in to the a planar stationary unit set body 101 a. [0260] The magnetic switch zero assembly 41 can have a magnetic switch zero assembly symmetry axis 41 l. [0261] The magnetic switch zero assembly contact element 41 a, magnetic switch zero assembly voltage element 41 b, magnetic switch zero assembly shaft 41 c, magnetic switch zero assembly magnet 41 e, magnetic switch zero assembly magnet spring 41 f, magnetic switch zero assembly voltage element spring 41 g, magnetic switch zero assembly housing 41 h, magnetic switch zero assembly magnet first magnetic pole 41 x, and magnetic switch zero assembly magnet second magnetic pole 41 y, function in the same manner in the magnetic switch zero assembly 41 to the magnetic switch phase assembly contact element 40 a, magnetic switch phase assembly voltage element 40 b, magnetic switch phase switch assembly shaft 40 c, magnetic switch phase assembly magnet 40 e, magnetic switch phase assembly magnet spring 40 f, magnetic switch phase assembly voltage element spring 40 g, magnetic switch phase assembly housing 40 h, magnetic switch phase assembly magnet first magnetic pole 40 x, and magnetic switch phase assembly magnet second magnetic pole 40 y, in the structure and operation of the magnetic switch phase assembly 40 , respectively. [0262] FIG. 11 b is a partial cut-away view schematic illustration of an exemplary, illustrative embodiment of a planar stationary unit set 101 , according to the present invention. [0263] The planar stationary unit set 101 includes a magnetic switch phase assembly 40 which is connected to magnetic switch phase wire 40 j and a magnetic switch zero assembly 41 , which is connected to a magnetic switch zero wire 41 j. The magnetic switch phase assembly 40 and the magnetic switch zero assembly 41 are located on a single plane, as seen in the figure, and each at the same distance from a planar stationary unit ground element 12 , which is connected to a planar stationary unit ground element wire 12 j. [0264] The magnetic switch phase assembly 40 includes a magnetic switch phase assembly magnet first magnetic pole 40 x, (for example, north pole) and a magnetic switch phase assembly magnet second magnetic pole 40 y, (for example, south pole) which are in of opposite polarity to the magnetic switch zero assembly magnet first magnetic pole 41 x, (for example, north pole) and the magnetic switch zero assembly magnet second magnetic pole 41 y, (for example, south pole) of the magnetic switch zero assembly 41 . The magnetic switch zero assembly 41 has a magnetic switch zero assembly shaft 41 c, a magnetic switch zero assembly voltage element 41 b, a magnetic switch zero assembly contact element 41 a, a magnetic switch zero assembly magnet spring 41 f, a magnetic switch zero assembly voltage element spring 41 g, a magnetic switch zero assembly housing 41 h, and a magnetic switch zero assembly housing end disk 41 i, and can have a magnetic switch zero assembly symmetry axis 41 l. [0265] The magnetic switch phase assembly 40 , the magnetic switch zero assembly 41 , and the planar stationary unit ground element 12 , are encased in to a planar stationary unit set body 101 a. [0266] Despite including the word “zero” in the magnetic switch zero assembly 11 and related components' names it is to be understood that this is not to limit the use of the present invention to be used with alternating current type of electricity, but it can be used with other types of electricity, such as direct current. [0267] FIG. 12 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a mobile unit set 102 , according to the present invention. [0268] Mobile unit set 102 including the mobile unit phase assembly 20 and the mobile unit zero assembly 21 . [0269] The mobile unit zero assembly 21 has a mobile unit zero assembly contact element 21 a, a mobile unit zero assembly magnet 21 e, a mobile unit zero assembly housing 21 h, a mobile unit zero assembly housing end disk 21 i, and a mobile unit zero assembly wire 21 j. The mobile unit zero assembly 21 can have a mobile unit zero assembly symmetry axis 21 l. [0270] The mobile unit phase assembly 20 , and the mobile unit zero assembly 21 are both encased in a mobile unit set body 102 a [0271] FIG. 12 b is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of a mobile unit set 102 , according to the present invention. [0272] Mobile unit set 102 including the mobile unit phase assembly 20 , the mobile unit zero assembly 21 , and the mobile unit ground element 22 , connected to mobile unit ground element wire 22 j. The mobile unit zero assembly 21 has a mobile unit zero assembly contact element 21 a, a mobile unit zero assembly magnet 21 e, a mobile unit zero assembly housing 21 h, a mobile unit zero assembly housing end disk 21 i, and a mobile unit zero assembly wire 21 j. The mobile unit zero assembly 21 can have mobile unit zero assembly symmetry axis 21 l. [0273] The mobile unit phase assembly 20 , the mobile unit zero assembly 21 , and the mobile unit ground element 22 are encased in a mobile unit set body 102 a. [0274] FIG. 13 a is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power 100 , according to the present invention. [0275] The planar stationary unit phase assembly 10 and the planar stationary unit zero assembly 11 being positioned aside one another. [0276] The mobile unit phase assembly 20 and the mobile unit zero assembly 21 being positioned aside one another. [0277] In the present illustration, it is possible to see that the mobile unit phase assembly 20 and the mobile unit zero assembly 21 are aligned with the planar stationary unit phase assembly 10 , and the planar stationary unit zero assembly 11 . [0278] FIG. 13 b is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power 100 , according to the present invention. [0279] The present figure illustrates the use of a magnetic switch phase assembly 40 as a first type of a planar stationary unit phase assembly 10 and a magnetic switch zero assembly 41 as a first type of a planar stationary unit zero assembly 11 . [0280] FIG. 13 c is a partial cut-away view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power 100 , according to the present invention. [0281] The figure shows the measure L 1 representing the width of the mobile unit zero assembly 21 , and L 2 , representing the distance between it and the mobile unit ground element 22 . [0282] This figure also shows the use of a planar stationary unit ground element 12 and a mobile unit ground element 22 in order to add grounding functionality to the operation of the apparatus for transferring electrical power 100 . [0283] FIG. 13 d is a partial cut-away side view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power 100 , according to the present invention. [0284] The present figure illustrates the use of a cantilever version of a magnetic switch assembly 34 as a second type of a planar stationary unit phase assembly 10 and a second type planar stationary unit zero assembly 11 (with a simple reversing of the cantilever version of a magnetic switch assembly magnet 34 e in the cantilever version of a magnetic switch assembly 34 located opposite of the mobile unit phase assembly 20 and the mobile unit zero assembly 21 ). [0285] This figure also shows the use of a planar stationary unit ground element 12 and a mobile unit ground element 22 in order to add grounding functionality to the operation of the apparatus for transferring electrical power 100 . [0286] FIG. 13 e is a partial cut-away view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power 100 , according to the present invention. [0287] The present figure illustrates the use a pair of cantilever version of electro-magnetic switch assemblies 35 as a third type of a planar stationary unit phase assembly 10 and a planar stationary unit zero assembly 11 . The polarity of the electro-magnet within the cantilever version of electro-magnetic switch assemblies 35 is determined by the direction of the current flowing thorough the cantilever version of electro-magnetic switch assembly electromagnet coil 35 q. [0288] This figure also shows the use of a planar stationary unit ground element 12 and a mobile unit ground element 22 in order to add grounding functionality to the operation of the apparatus for transferring electrical power 100 . [0289] FIG. 13 f is a front view schematic illustration of an exemplary, illustrative embodiment of mobile unit set 102 , according to the present invention. [0290] The mobile unit set 102 according to the illustrative embodiment of the present illustration includes a mobile unit phase assembly 20 , a mobile unit zero assembly 21 and a mobile unit ground element 22 , all the three are enclosed in a mobile unit set body 102 a. [0291] In the case described in the figure, the mobile unit phase assembly 20 , the mobile unit zero assembly 21 and the mobile unit ground element 22 cross sections are circular, but other shapes are possible as well. [0292] FIG. 14 a is a schematic diagram of a means of supplying DC voltage to at least one planar stationary unit set 101 , according to the present invention. [0293] The mains outlet plug 71 is plugged into an electrical power supply socket (usually a standard wall power outlet) and the AC to DC converter 72 converts the power coming from the outlet (usually 110V/220V AC voltage) to a much lower DC voltage (usually, not more than 20-30V, but could be more or less than that). The planar stationary unit voltage regulator 73 is used to regulate and maintain a constant supply voltage to the at least one planar stationary unit set 101 even under high load currents. [0294] FIG. 14 b is a schematic diagram of supplying the DC voltage from a mobile unit set 102 , (not shown in the present illustration), to a receiving portable electronic device's power plug 76 , according to the present invention, using a mobile unit voltage regulator 74 . [0295] The planar stationary unit sets 101 (not shown in the present illustration) supply a certain voltage level that may not fit the voltage requirements of the receiving electronic device. Therefore, it is required to regulate the incoming voltage to the appropriate voltage levels using the mobile unit voltage regulator 74 . [0296] FIG. 15 is a top view schematic illustration of an exemplary, illustrative embodiment of an apparatus for transferring electrical power 100 , according to the present invention. [0297] The figure also depicts several dimensions crucial to the safety of the apparatus for transferring electrical power, according to the present invention. [0298] The apparatus for transferring electrical power 100 , according to the embodiment described at the present illustration, includes a planar stationary unit grid 201 , which is comprised of a plurality of planar stationary unit sets 101 , and a mobile unit set 102 , also depicts several dimensions crucial to the safety of the apparatus for transferring electrical power, according to the present invention. [0299] The embodiment of the mobile unit set 102 in the present illustration is different from other embodiments of the mobile unit set 102 described earlier only in its size and dimensions. The operational principles remain the same. [0300] Planar stationary unit phase assemblies 10 and mobile unit phase assembly 20 serve in this instance for conducting a positive current, while planar stationary unit zero assemblies 11 and mobile unit zero assembly 21 serve in this instance for conducting a negative current and are set in a non-conductive planar stationary unit plus and minus assembly sets grid body 202 a. [0301] The dimension d 3 is the largest cross section width dimension of the planar stationary unit phase assembly 10 , and the dimension d 1 is the largest cross section width dimension of the planar stationary unit zero assembly 11 [0302] The dimension d 2 is the minimal distance of the mobile unit phase assembly 20 , and from the mobile unit zero assembly 21 to the mobile unit set body edge 102 b. [0303] The dimension d 4 is the distance between the mobile unit phase assembly 20 and the mobile unit zero assembly 21 . [0304] Dimensions d 1 , d 2 , d 3 , and d 4 are measured from the top view, as depicted in the present illustration on the sides of the planar stationary unit set 101 and the mobile unit set 102 facing each other in the power transferring condition. [0305] In order to prevent accidental contact between a live plate in the planar stationary unit grid 201 and a person, there must be sufficient insulation around the mobile unit phase assembly 20 and around the mobile unit zero assembly 21 . [0306] This is achieved by making the non-conductive mobile unit set body 102 a large enough to overlap any live plates in the planar stationary unit grid 201 . Therefore, the dimension d 2 must be larger than each one of the dimensions d 1 and d 3 . [0307] In order to prevent any shorts between the mobile unit phase assembly 20 and the mobile unit zero assembly 21 , the distance d 4 between them must be large enough so that no live power plate in the planar stationary unit grid 201 may touch both plates in the mobile unit set 102 simultaneously. [0308] This is achieved by making the distance d 4 between the mobile unit phase assembly 20 and the mobile unit zero assembly 21 larger than d 1 . [0309] This description refers to the case where all the dimensions of the planar stationary unit phase assemblies 10 , and the planar stationary unit zero assemblies 11 of the planar stationary unit grid 201 , are identical to each other. [0310] The mobile unit set 102 depicts a case where the mobile unit phase assembly 20 , is greatly larger than any single planar stationary unit phase assembly 10 and planar stationary unit zero assembly 11 . [0311] In such a case, it is not possible to use the planar stationary unit ground element 12 and the mobile unit ground element 22 , as they would cause shorts between one of the contact elements in the mobile unit set 102 contact elements in the planar stationary unit grid 201 . [0312] Such a mobile unit set 102 (compared to a single planar stationary unit set 101 ) ensures that there will always be at least one planar stationary unit phase assembly 10 under the mobile unit phase assembly 20 , and at least one planar stationary unit zero assembly 11 under the mobile unit zero assembly 21 , with no regards to the orientation of the mobile unit set 102 , on the plane seen in the top view of the present illustration, when placed on the planar stationary unit grid 201 . [0313] Although the 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, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

An apparatus and method for transferring power from a stationary unit to a mobile unit are introduced in order to improve on the existing methods of supplying power to appliances and mobile devices. The stationary unit is comprised of multiple magnetic and electromagnetic switches, which are activated only when in close proximity to a mobile unit comprising of a set of magnets of opposite polarity to the magnetic and electromagnetic switches in the stationary unit thus ensuring a safe and easy to use system for supplying power from the stationary unit to the mobile unit. The stationary unit may be large enough to allow the connection of multiple mobile units on a single stationary unit. Each mobile unit can then adjust the voltage supplied by the stationary unit to fit the requirements of its own appliance or mobile device thus allowing different types of devices to connect to the same source (the stationary unit).

CROSS-REFERENCE TO RELATED APPLICATIONS This application is the U.S. national phase of PCT Application No. PCT/EP2012/062307 filed on Jun. 26, 2012, which claims priority to German Patent Application No. 10 2011 078 287.7 filed on Jun. 29, 2011, the disclosures of which are incorporated in their entirety by reference herein. TECHNICAL FIELD The present invention relates to an arrangement for emitting light having essentially point light sources and a light directing element for influencing the light of the light sources. BACKGROUND Sources and Light Deflection Elements Point light sources, in particular halogen lighting means or LED-based lighting means, have by now become central to lighting technology development in particular owing to their energy efficiency. Many point light sources in all power classes are available on the market, so that all lighting technology applications can be carried out with these light sources. Often, particularly for the illumination of domestic and business rooms, the desire arises to achieve homogeneous light emission over a large light exit surface, so that for example the light output can take place homogeneously from the ceiling of a room. Taking into account reliability and energy efficiency aspects, the use of a multiplicity of the aforementioned point light sources is desirable. In this case, however, there is the problem of combining or converting the light emission of a plurality of point light sources in such a way that the desired combined light emission—which may for example be homogeneous—is achieved. To this end, large-surface light emission elements which combine the light output of a plurality of point light sources are known from the prior art. These may be formed from a plurality of lens elements, in which case the lens elements may also be combined integrally. According to a previously known combination of a plurality of lens elements, one point light source is respectively to be assigned to one of the lens elements, the point light source then being arranged in a cavity of the lens element. Each of the lens elements is formed in order to output a part of the light of the assigned light source essentially directly, while another part of the light is reflected by the lens element so as to obtain a relatively accurately delimited region of the light output, or a relatively accurately delimited lit region, which is illuminated by the light output of the one lens element. The combination of the light output, or the lit regions, then produces the desired lighting technology effect—for example desired homogeneous illumination of a surface. SUMMARY It is an object of the invention to improve a light emission element and a method for producing a corresponding light emission element, in such a way that in an arrangement for emitting light, corresponding to the type described above, the light emission of a plurality of point light sources can be combined in a straightforward way, or the possibilities for producing the arrangement for emitting light are optimized. This object is achieved by the features of the independent claims 1 , 15 and 16 . The dependent claims relate to refinements of the invention. According to the invention, a light directing element for influencing the light of at least two essentially point light sources arranged next to one another has a bounding surface or bounding surface section which is arranged in the beam path of the light of both the first light source and the second light source, the bounding surface or bounding surface section forming a light entry surface for the light of the first light source into the light directing element and the bounding surface or bounding surface section simultaneously forming a reflection surface for the light of the second light source on its side facing away from the light entry surface. In this context, “arranged next to one another” is to be understood as meaning that there is no other light source on the shortest connecting path between the first and second point light sources. Preferably, the light sources “arranged next to one another” are arranged on a common plate-like, or planar, support element, or a planar support surface, so that they have an essentially identical light output direction with respect to the support element. An arrangement according to the invention for emitting light accordingly has a plurality of essentially point light sources, and a light directing element having a bounding surface or bounding surface section which is arranged in the beam path of the light of both a first light source and a second light source, the bounding surface or bounding surface section forming a light entry surface for the light of the first light source into the light directing element and the bounding surface or bounding surface section simultaneously forming a reflection surface for the light of the second light source on its side facing away from the light entry surface. In contrast to solutions such as are known from the prior art, the light directing element configured according to the invention now has regions which are used simultaneously for influencing the light of a plurality of light sources, but fulfill a different function—refractive on the one hand and reflective on the other hand—in relation to the light sources. With the aid of these so-called cooperative regions, in particular the integration density of the point light sources can be increased—for example compared with the case in which separate lens elements are provided—so that more versatile possibilities are obtained for simple combination of the light emission of a plurality of point light sources. Furthermore, the configuration according to the invention likewise offers production advantages in the manufacture of the light directing element, since in particular the complexity of the structure can be reduced with the same efficiency, as will be illustrated below with the aid of special examples. The essentially point light sources may be formed by one or more LEDs, which for example form a so-called LED cluster. In this case, “essentially point” means that a centrally symmetrical arrangement (group) of a plurality of LEDs is obtained, which only has differences from central symmetry due to the sizes of individual LEDs. Furthermore, essentially point light sources are also intended to mean halogen lamps, incandescent lamps and other lighting means having similar dimensions, the extent of the light output region of the light sources preferably not exceeding the single-digit centimeter range in a section plane parallel to the light output direction of the arrangement for emitting light. Preferably, the light sources are arranged next to one another, for example on a common, preferably planar or plate-shaped support element. The light directing element particularly preferably has a positionally fixed arrangement with respect to the light sources; for example, this may likewise be achieved by a common support element. This provides the possibility of providing established light emission, in particular with a spatially established proportion of mixed light of the light sources. It is nevertheless possible that one or more light sources may be arranged movably with respect to the light directing element. Particularly preferably, the light directing element may comprise cavities, in each of which one of the light sources is arranged. The aforementioned bounding surfaces or bounding surface sections in this case form the contour of these cavities. The light directing may be improved by one or more of the cavities respectively at least partially forming an optimized light entry surface in the form of a so-called lens region for the light of the light sources. For example, the bottom surface of the cavities could also be configured in the form of a lens. Particularly preferably, the light directing element may essentially be formed in the shape of a plate, for example in order to permit a particularly compact design even with a large number of light sources, together with simple manufacture. For example, the cavities are in this case arranged facing a light exit surface of the light directing element, so that direct light emission can preferably take place via the light directing element, or its light exit surface. Furthermore, for example, in this way a common support element could readily be provided for the light sources and the light directing element. In one refinement, the cavities have a polygonal base surface, or a polygonal surface projection. For example, the density of the arrangement of the light sources can thereby be increased and, furthermore, in this way it is possible to provide combinations of cavities whose surface projection fully covers a planar light exit surface of a light guide element. The surface projection of an individual cavity or of all cavities of the light directing element preferably has a polygonal shape. According to one refinement of the invention, furthermore, the reflection of the light of the second light source at the bounding surface or bounding surface section configured according to the invention takes place by total internal reflection. For example, it is thereby possible to avoid semitransparent sections which, for example, would be formed so as to be transparent for the light of the first light source while they are reflectively coated for the light of the second light source, although according to the invention this is not necessarily ruled out. In the scope of the invention, it is likewise possible to provide semitransparent materials or corresponding coatings, particularly in the region of the bounding surface or bounding surface section. It is furthermore conceivable for the light emission achieved with the arrangement according to the invention to be homogeneous; for example, the light directing element may be formed in order to collimate the light of the light sources. In one exemplary embodiment, it is conceivable for the bounding surface or bounding surface section configured according to the invention to be formed in a planar fashion, so that a particularly simple arrangement of the light sources and corresponding simple manufacture of the light directing element is made possible. According to another exemplary embodiment, furthermore, the bounding surface or bounding surface section may also be curved, particularly preferably parabolically. In this case, it should be pointed out particularly that this includes in particular a polygonal base shape of cavities of the light directing element. Particularly optimized light directing can therefore be produced. According to one refinement of the invention, furthermore, the light directing element is formed in order to convert the light of the first light source into a first light output characteristic and the light of the second light source into a second light output characteristic, the first and second light output characteristics being formed symmetrically, particularly preferably with symmetry of translation, with respect to one another. In this way, for example, homogeneous light emission can be produced with a multiplicity of essentially point light sources which, in an exemplary embodiment that is particularly simple to implement in design terms, may also be formed identically to one another. Another possibility for improving the arrangement for emitting light consists, for example, in the arrangement for emitting light comprising a plurality of pairs of first and second light sources. It is in turn advantageous in design terms for the plurality of pairs preferably to be arranged in a row or a two-dimensional grid, so that the light directing element forms, for example, at least one axis of homogeneous light output. A plurality of pairs may in turn be arranged correspondingly adjacent, i.e. there are no other light sources on the shortest connecting path between the pairs, although this does not exclude the use of further light sources. According to one refinement of the invention, furthermore, the arrangement for emitting light may comprise a plurality of light sources having mutually different light output. For example, a different color spectrum or a different color temperature, a different luminous density, which may for example also be polarization-dependently different, may be envisioned. For example, this may involve LED light sources which are preferably arranged as LED clusters, particularly preferably in an essentially point-like fashion. In this case, in particular, one or more LED clusters may respectively comprise LED light sources having mutually different light output (luminous density, color spectrum or color temperature). Particularly preferably, the light sources having mutually different light output are arranged in a regular grid. For example, in this case it is also conceivable for the first light source to have a different light output than the second light source. Furthermore, a method for producing a light directing element according to the invention may comprise the following steps: producing, for example injection-molding, an essentially planar light directing element; shaping the light directing element preferably by cutting so that the desired shape is obtained. In the case of a plurality of pairs of first and second light sources, step B) may for example be carried out in such a way that at least one bounding surface or bounding surface section which forms a light entry surface for the light of the first light source into the light directing element, and simultaneously a reflection surface for the light of the second light source, is assigned to each pair of first or second light sources. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail below with the aid of the appended drawing, elements which are the same being provided with the same references in all the representations. FIGS. 1 a ) to 1 d ) show a first exemplary embodiment of an arrangement for emitting light; FIGS. 2 a ), b) show a second exemplary embodiment of a light directing element according to the invention; FIGS. 3 a ), b ) show a third exemplary embodiment of a light directing element according to the invention; FIG. 4 shows a detail representation which illustrates the light mixing with the aid of an exemplary embodiment of an arrangement for emitting light; FIG. 5 shows an example of the light output of an individual light source with the aid of an exemplary embodiment of the light directing element; FIGS. 6 a ) to 6 c ) show a fourth exemplary embodiment of an arrangement for emitting light; FIGS. 7 a ) to 7 c ) show a fifth exemplary embodiment of an arrangement for emitting light; FIGS. 8 a ) to 8 d ) show exemplary embodiments of a method for producing a light directing element; and FIG. 9 shows a representation of an arrangement for emitting light according to the prior art. DETAILED DESCRIPTION The use of point light sources for two-dimensional light output requires immense design as well as manufacturing technology outlay in order to achieve the desired illumination, since in particular the interaction of a plurality of light sources has to be taken into account. In particular, this frequently results in relatively complicated shapes of a light directing element which carries out the common light emission of a plurality of point light sources. FIG. 9 shows by way of example an arrangement for emitting light according to the prior art, which establishes the interaction of a plurality of point light sources. The represented arrangement for emitting light according to the prior art comprises a plurality of transparent lens elements 1000 , which are connected to form a common light directing element with the aid of a light exit plate 1200 . Each lens element 1000 has a frustoconical configuration with a hemispherical depression, or cavity, in which a light source 1100 assigned to the lens element 1000 is arranged. The light output of the light source 1100 is thus coupled over a large solid angle range into the lens element 1000 . The lens element is in this case shaped in such a way that a part of the light coupled in is output essentially directly via a common light exit plate 1200 . Another part is reflected—usually totally internally reflected—at lateral sections of the lens elements 1000 which are formed as a reflector and deviated in the direction of the common light exit plate 1200 . With suitable selection of the proportions between reflected and directly output light, for example, homogeneous light output can be achieved over the light exit plate. This concept, however, has some disadvantages. For example, the density of the arrangement of the light sources 1100 is restricted, or conditioned, by the size of individual lens elements 1000 , so that the possibilities for configuration of the light emission are limited. Furthermore, in particular the light output in the transition region between two adjacent lens elements represents a challenge in the design and manufacture of the lens elements 1000 . The invention is based on the need to reduce said design and production technology outlay for the light directing element, and to improve the possibilities of the interaction of a plurality of point light sources. If, for example, homogeneous light output is intended to be achieved over the entire ceiling of a room, or at least over a sizeable surface, then the use of light guides may also be envisioned. For light emission over sizeable surface regions, however, the interaction of a plurality of light guides is here again necessary, so that the above-described arrangement of light sources in a grid will preferably be considered. In this case, the overlap region of the light emission of at least two light sources is to be adapted in such a way that desired light output results, which is particularly difficult for example for the aforementioned homogeneous light output. The production of other lighting technology effects can also be optimized with the aid of the invention. A first exemplary embodiment of the invention is represented in a perspective view in FIGS. 1 a and 1 b . In a similar way to the above-described lens arrangement of the prior art, in this example a plurality of point light sources are to be combined with a light directing element 500 for the light output of the light sources. In the exemplary embodiment, a regular arrangement of light sources—which are not represented in FIGS. 1 a and 1 b —is provided in a grid, the light sources respectively being arranged in a similar way to the above-described lens elements 1000 in cavities 505 of the light directing element, in such a way that precisely one light source is assigned to each cavity 505 . The arrangement of the cavities 505 may for example be seen in detail in FIG. 1 a , which shows a perspective view of the light directing element 500 . FIG. 1 b furthermore shows the lower side of the light directing element 500 , which lies opposite the light sources and which forms a light exit surface of the light directing element. The representations of FIGS. 1 to 3 are respectively to be understood identically in the following way for the subindices a and b for various exemplary embodiments. The subindex a in each case denotes a perspective view of the light directing element 500 on the side of the light directing element 500 facing toward the light sources, and the subindex b in each case shows a perspective view of the light emission surface of the light directing element 500 . The lighting technology effect, as described below, of the invention can be seen in detail in a sectional representation of the exemplary embodiment of FIGS. 1 a and 1 b , which is shown in FIGS. 1 c and 1 d. According to the invention—as shown in FIGS. 1 c and 1 d —an arrangement for emitting light is provided, which comprises a plurality of light sources arranged next to one another. In order to explain the functionality of the light directing element 500 , a first point light source 100 and a second point light source 200 —located next to the former—will be discussed below, although in general they are identical light sources. The light directing element 500 consists of a plurality of lens-like regions, which are arranged in accordance with the arrangement of the light sources 100 , 200 . Each lens-like region has a depression or cavity 505 , in which the associated light source is arranged. In order to use the light of the light sources effectively, in this case the light sources are preferably arranged fully or almost fully inside the associated cavity 505 . The surfaces 511 , 512 , 513 and 550 of the cavity 505 then form the corresponding light entry surface for the light. A first part of the light is refracted when entering the light directing element 500 , in such a way that it leaves the latter directly on the lower side. Another part, on the other hand, which strikes the regions 513 and 550 , is—as explained below and shown in FIG. 1 c -reflected at the surface 550 of the adjacent cavity 505 and deviated toward the lower side. The particular feature of the arrangement according to the invention is the aforementioned bounding surfaces or bounding surface sections 550 , which lie in the beam path of the light of both the first point light source 100 and the second point light source 200 . In this case, the bounding surface or bounding surface section 550 on the one hand forms a light entry surface for the light of the first point light source 100 , and on the other hand the bounding surface or bounding surface section 550 simultaneously forms a reflection surface for the light of the second point light source 200 on its side facing away from the light entry surface, as shown by the ray profiles shown in FIG. 1 c. The light mixing is represented by way of example with the aid of the light rays R 100 coming from the first point light source 100 and R 200 a coming from the second point light source 200 . The light ray R 100 is reflected at the bounding surface II in such a way that it leaves the light directing element 500 approximately at the same exit angle as the light ray R 200 a . The configuration, according to the invention, of the bounding surface I is furthermore illustrated with the aid of the light rays R 100 and R 200 . The light ray R 100 enters the light directing element 500 in the region of the bounding surface I, or 550 , while the light ray R 200 is reflected at the same position on the bounding surface I, or 550 , and a region of the common light path of the light of a plurality of point light sources is thus in turn established with the aid of the bounding surface I, or 550 , according to the invention. An interaction of at least two point light sources 100 , 200 can thus particularly advantageously be optimized and adapted with the aid of the invention. The bounding surface or bounding surface section 550 is formed as a reflection surface; the light emission of one of the point light sources—in this case the light emission of the second point light source 200 —can thus be spatially limited. At the same time, the bounding surface or bounding surface section 550 acts as a light entry surface for the light of the other point light source—in this case the first point light source 100 —so that a spatially delimited overlap region of the light output of the two light sources 100 , 200 is already established by properties of the light directing element 500 . In contrast to the combination of the lens elements 1000 of the prior art, a region of overlapping light output of the first and second point light sources 100 and 200 is therefore already established within the light directing element, so that an interaction of the light output of the first and second point light sources 100 and 200 which is simple in design terms and, for example, can be established independently of the distance of an illuminated surface can be achieved. Another advantage of the solution according to the invention is furthermore that, owing to these “cooperative regions” of the lens arrangement, i.e. of the regions used in common by adjacent light sources 100 , 200 and delimited by the surface sections 550 , the lenses so to speak merge into one another and accordingly a more compact arrangement for the light sources 100 , 200 and a higher luminous density can be achieved. In the exemplary embodiment of FIGS. 1 c and 1 d , reflection of the light of the second point light source 200 at the bounding surface or bounding surface section 550 takes place by total internal reflection. The arrangement for emitting light may in this case be provided for direct mounting on or at a support, for example on a ceiling, supports of a suspended ceiling, a wall or the like. Furthermore, integration into a light housing or a housing frame may also be envisioned. Preferably, the light directing element 500 forms the only light exit surface of the arrangement for emitting light and, to this end, it may for example be arranged in, or close, an opening of a light housing, or it may be connected to a support in such a way that no additional light can emerge from the arrangement, or the light. Particularly preferably, the light directing element 500 is formed in a planar fashion, that is to say its height extent differs from both its width extent and its length extent, so that the height of the light directing element establishes a narrow side of the light directing element 500 , while other surfaces form a wide side of the planar light directing element 500 . In one refinement of the invention, the first and second light sources 100 and 200 are arranged on a wide side of the light directing element. Particularly preferably, an opposite wide side forms a light exit surface of the light directing element 500 . According to the invention, optical surfaces of the light directing element 500 , or particular regions thereof, are therefore to be used together for a plurality of light sources. Owing to the fact that optical elements assigned to the light sources are also used by adjacent light sources, the single optical element has a relatively small installation size. In particular, this makes, extremely planar and thin optical plates possible as light directing elements 500 , which also permit integration of a multiplicity of first and second point light sources 100 and 200 , so that for example the grid-like arrangement of the first and second light sources 100 and 200 according to the perspective views of FIGS. 1 a, b to 3 a, b can be obtained. Each of the light sources may simultaneously fulfill the role of the first and second point light sources 100 and 200 , i.e. each of the light sources interacts with each immediately adjacent light source via the light directing element 500 , in such a way that each adjacent light source forms a second point light source 100 in the sense of the invention for the respective light source, in which case the respective light source is to be regarded as a first point light source in the sense of the invention. Preferably, the light directing element 500 is formed from an essentially transparent material, preferably glass, PMMA (polymethyl methacrylate) or another transparent plastic. This does not exclude the possibility that the light directing element 500 also comprises regions of a nontransparent material. Particularly preferably, the light directing element 500 is formed in one piece; this, however, includes the possibility that the light directing element 500 , for example for particularly large light exit surfaces, is formed in a plurality of parts and for example comprises a plurality of planar sections, which are configured so as to be connectable to one another, preferably with integrated fastening means. In particular, the manufacture and mounting of the light directing element 500 can be optimized in this way. The arrangement for emitting light according to FIGS. 1 c and 1 d is formed, in particular, for homogeneous light output; depending on the application, however, other configurations may also be envisioned. In the case of the exemplary embodiment described, the homogeneous light is output via a light exit surface of the light directing element 500 which lies opposite the first and second point light sources 100 , 200 . In particular, the light directing element 500 is formed in order to collimate the light sources 100 , 200 . The light directing element 500 according to FIGS. 1 c and 1 d , formed in a planar fashion, comprises, as already mentioned, a plurality of cavities 505 , in each of which one of the first or second point light sources 100 or 200 is arranged. As already described, the detail of the arrangement of the cavities 505 may again be seen particularly in FIGS. 1 a and 1 b , which show another representation of the exemplary embodiment. According to the exemplary embodiment, the cavities are arranged in a row or a two-dimensional grid, as will become clearer below. Both the cavities and the first and second point light sources 100 , 200 are in this case arranged opposite a light exit surface of the light directing element 500 , which is oriented in the direction of the surface extent of the light directing element 500 . At the same time, as described above, the light exit surface of the light directing element 500 also forms a light exit surface of the arrangement for emitting light. In the exemplary embodiment of FIGS. 1 a to 1 d , parts of the cavity-delimiting surface 510 form a bounding surface or bounding surface section 550 according to the invention. According to FIGS. 1 c and 1 d , the bounding surface section 550 is formed in a planar fashion, so that a light entry surface for the light of the first point light source 100 can be formed in a particularly simple way. Furthermore, a surface can be oriented optimally with respect to the second point light source 200 in such a way that at least one light subbeam of the light output by the second point light source 200 strikes the bounding surface or bounding surface section 550 more shallowly than the total internal reflection angle. Simple adaptability of the reflection region of the bounding surface or bounding surface section 550 , and therefore of the overlap region of the light output of the first and second point light sources 100 , 200 , can be implemented in this way. The cavity-delimiting surface 510 comprises—immediately adjacent to the bounding surface or bounding surface section 550 —two further planar surfaces 511 and 512 , which form the bottom region of the cavity and which are arranged, in order to guide the direct light output of the first point light source 100 , inclined in a “V” shape with respect to one another at an obtuse angle, preferably between 120 and 160 degrees, and collimation of the light of the first point light source 100 is for example achieved in this way. Furthermore, a further bounding surface 513 formed in a planar fashion, which may constitute a bounding surface or bounding surface section 550 formed according to the invention for a further point light source 200 (not shown), is arranged following the two surfaces 511 and 512 arranged in a “V” shape. The light source (not shown) is in this case arranged mirror-symmetrically with respect to a mirror plane which contains the connecting line from the first point light source 100 to the apex of the “V” of the surfaces 511 , 512 arranged in a “V” shape. In combination, the surfaces 550 , 511 , 512 and 513 describe the cross section of a cavity 505 in which the first point light source 100 is arranged. The apex of the “V” in this case forms a center of the cavity 505 , the connecting line of which to the first light source 100 lies in a symmetry plane of the cavity 505 , or a first symmetry plane S 1 of the light directing element 500 , in which case the light output of the first point light source takes place symmetrically with respect to this first symmetry plane S 1 of the light directing element and the symmetry plane S 1 may in particular contain a main emission direction of the first point light source 1 . A further, second symmetry plane S 2 of the light directing element 500 may, however, be established by a normal to the connecting line of the first and second point light sources 100 and 200 . Said normal, which symmetrically divides the connecting line, is in this case contained in the second symmetry plane S 2 . Furthermore, the symmetry plane S 2 may also divide the normal of said connecting line in a different intended ratio, which, however, is periodically reproduced in the combination of a plurality of point light sources. In particular, the first or second symmetry planes S 1 or S 2 may be arranged in a regular grid, so that a simple possibility is thereby provided for combination of a plurality of point light sources. This includes, in particular, the possibility that the grid sizes of the first and second symmetry planes S 1 and S 2 are selected differently. Corresponding refinements will be described in more detail below. FIG. 1 a shows the planar configuration of the light directing element 500 of FIGS. 1 c and 1 d in more detail. The cavities 505 are configured essentially frustoconically in this case, the lateral surface of the conical frustum comprising the bounding surface section 550 according to the invention. The top surface of the conical frustum, facing away from the first or second light source 100 or 200 , itself in turn has the shape of a cone, the vertex angle of which differs from the vertex angle of the conical frustum so that the already described combination of the surfaces 511 , 512 , 513 and 550 according to FIGS. 1 c and 1 d is obtained in cross section and a conical collimating section of the light directing element 500 is formed. The first and second point light sources 100 , 200 are in this case arranged in a square grid, and respectively assigned to one of the cavities—which in this case are formed frustoconically. A uniform arrangement of preferably identical light sources can be achieved in this way. The square grid is reproduced in the surface projection of the base surface of the cavities. As represented in FIG. 1 b , the light exit surface has rectangular or square elevations; each of the elevations in this case forms the above-described frustoconical cavity on the side of the light directing element 500 facing toward the first or second light sources 100 , 200 . On the top surface of the elevations, a frustoconical light shaping element 570 is in turn arranged, which thus has a “V”-shaped cross section and therefore likewise improves the collimation of the light. Furthermore, other light shaping elements 570 may nevertheless also be envisioned, which for example deviate the direct light output of the associated light source into a preferential direction and which, for example, are formed in order to output the light in a collimated fashion in this preferential direction. The connecting sections of the square elevations and their side surfaces respectively optimize light mixing elements 580 for mixing the light of adjacent light sources 100 , 200 . The side surfaces and the connecting sections approximately have a “W” shape in combination in cross section. This “W” shape may in turn be regarded as the combination of a first “V”-shaped section, which is assigned to a side surface of a square elevation, and a second “V”-shaped section, which is assigned to an adjacent side surface of a further square elevation. The light mixing elements 580 are preferably arranged following the bounding surface or bounding surface section 550 according to the invention in the light path of the first and second point light sources 100 and 200 . The arrangement symmetrical with respect to the first and second point light sources 100 , 200 , in particular symmetrical with respect to the symmetry plane S 2 , in this case simultaneously conditions the establishment of a region in which the mixing of the light emission of the first and second point light sources takes place. In combination, by a shape which is preferably doubly collimating, or limiting for the light output, the “W”-shaped section thus optimizes the light mixing in the region between the cavities, i.e. in the region of the overlap of the light output of the first and second light sources 100 and 200 . According to another refinement, the bounding surface or bounding surface section 550 may also be curved. Particularly preferably, the bounding surface or bounding surface section 550 is parabolically shaped, so that a light source—preferably the first and second light source 100 and 200 —can be arranged at the focal point of the associated parabola and collimation of at least one subbeam of rays of the first or second point light source 200 takes place. In the exemplary embodiment represented, for example, the bounding surface of the cavity in which the first point light source 100 is arranged may be curved so that this bounding surface section is parabolically shaped in such a way that the second point light source 200 is arranged at the focal point of the associated parabola. The above refinement includes the possibility that curved regions of the bounding surface or bounding surface section 550 are combined with planar regions of the bounding surface or bounding surface section 550 . For example, the combination of curved surfaces and parabolic sections may also be provided with sections of the frustoconical or conical cavities. In another exemplary embodiment, according to FIGS. 2 a and 2 b , the cavity 505 has a polygonal base surface, in particular a square base surface, so that the surface projection of the cavity 505 reproduces the arrangement of the light sources with an offset. In contrast to the exemplary embodiment described above, the cavities 505 are now shaped pyramidally or frustopyramidally, each side surface of the pyramid or frustopyramid forming a bounding surface section 550 according to the invention, i.e. in particular a reflection surface and a light entry surface, in which case the light incidence of adjacent light sources into the frustopyramid may thus be fully restricted. The light exit surface in this case likewise has square elevations; as will become clearer below, however, this shape may be adapted to any polygonal configuration of the cavities or the projection surface thereof, so that for example triangular, rectangular, pentagonal, hexagonal or other polygonal elevations of the light exit surface lie within the scope of the invention. In the exemplary embodiment of FIGS. 2 a and 2 b , the light mixing elements 580 are formed by the side surfaces of the polygonal elevations and have a “V”-shaped cross section, so that the light exit surface can on the one hand be configured in a visually particularly attractive way and, on the other hand, particularly advantageous light mixing is obtained. Furthermore, light shaping elements 570 on the top surface of the polygonal elevations can be obviated in this exemplary embodiment; as can be seen in FIG. 2 a , these are produced on the inner side of the cavity, facing toward the first or second light sources 100 or 200 . The base surface of the cavity has, facing toward each side surface, a prismatic, sawtooth or triangular elevation and these optimize, in particular widen, the direct light output of the first or second light sources 100 , 200 assigned to the cavity. A refinement of the invention, in particular of the exemplary embodiment of FIGS. 2 a and 2 b , which is represented in FIGS. 3 a and 3 b , shows a light directing element 500 which has polygonal pyramidal cavities 505 with a hexagonal base surface, and respectively polygonal, hexagonal elevations of the light exit surface. Each of the side surfaces is in this case formed in order to reflect the light of one of the second point light sources 200 , which is arranged in an adjacent cavity 505 , so that six second light sources 200 in a respectively adjacent cavity 505 are assigned to the first light source 100 in this exemplary embodiment. The light emission of the second light source 200 may in this case be fully restricted with respect to the first light source 100 by the bounding surfaces or bounding surface sections 550 according to the invention, so that the cavity 505 is closed for light of the assigned—in this case the six—second light sources 200 . This may, for example, also be achieved for any polygonal cavities 505 or any number of adjacent light sources. The base surface of the cavities 505 , as well as the light mixing elements 580 , are configured in accordance with the exemplary embodiment described above. The limiting case of a polygonal cavity having a large number of bounding surfaces may in this case be described by an elliptical or circular base surface of the cavity, so that for example the frustoconical cavity of the above-described exemplary embodiment of FIGS. 1 a to 1 d is obtained. FIG. 4 again illustrates the lighting technology effect, according to the invention, of the light mixing within the light directing element 500 . An overlap region of the light output of the first and second point light sources 100 and 200 can be established independently of the distance of the illuminated surface. This offers the possibility of optimized compensation for intensity differences, or other light output differences, of the first and second point light sources 100 and 200 already in the light directing element 500 , so that for example established masking of the light emission can take place. In this way, for example, homogeneous light emission from the light directing element 500 can also be improved. With the aid of the refinements described above, not only can an attempt be made to achieve homogeneous light output over the light emission surface of the light exit element, but furthermore inhomogeneous light emission may also be envisioned, according to the invention the interaction of a plurality of point light sources being optimized. For example, FIG. 5 shows the light emission of an arrangement for emitting light, having a light directing element 500 which carries out inhomogeneous light emission. The choice of the base surfaces of the cavities, or the polygonal shape of the cavities, may in particular be adapted to the desired light output, so that for example it is possible to achieve a rotationally symmetrical, rectangular, square, cross-shaped or other polygonal light distribution for a single one of the first or second point light sources. Owing to the fact that the grid of the light sources, which may in particular be described by a grid of symmetry planes S 1 , is reproduced in a grid of the symmetry planes S 2 with an identical grid size, despite inhomogeneous light output of an individual cavity, or of a light source (for example the first point light source 100 ) assigned to this cavity, it is possible to achieve an interaction with a plurality of light sources in such a way that the overall light output of the arrangement for emitting light nevertheless appears homogeneous in terms of the luminous density. Particularly preferably, this may also be achieved for a surface to be illuminated. In order to achieve further lighting technology effects, regions of exaggerated—i.e. increased or reduced—luminous density may particularly advantageously be achieved in that the grid size S 2 differs at least in subregions of the light directing element from the grid size S 1 . As an alternative or in addition, a plurality of light sources of the arrangement for emitting light, in particular the first and second point light sources 100 and 200 , may also have a different light output than one another. Particularly preferably, this relates to the luminous density, color spectrum, the color temperature or, for example, also the polarization of the light. In one refinement, in particular, the first point light source 100 has a different light output than the second point light source 200 . With the aid of the configuration, according to the invention, of the arrangement for emitting light, or of the light directing element 500 , it is thus particularly advantageously possible to achieve light mixing of two adjacent point light sources. With the aid of light sources having different light output, this may for example also be used for color mixing. FIGS. 6 a to 6 c shows another exemplary embodiment of a light directing element 500 configured according to the invention, FIG. 6 a showing a view from above, FIG. 6 b showing the lower side of the light directing element 500 and FIG. 6 c showing a sectional representation. Likewise as in the exemplary embodiment according to FIGS. 3 and 3 b , the light sources 100 , 200 and associated cavities 505 of the light directing element 500 are arranged in a hexagonal structure, although—as mentioned above—other regular arrangements may of course also be used. The transition between two adjacent cavities 505 is here again formed by a cooperative region, which is delimited by the surfaces 550 and now is formed essentially triangularly in cross section. A first particular feature of the variant represented is that elevations respectively extending significantly in the direction of the associated light source 100 or 200 are formed inside the cavities, and these will subsequently be referred to as lens regions 560 . As can be seen from the sectional representation, these lens regions 560 are formed approximately frustoconically in respect of their outer circumference, i.e. according to the sectional representation they comprise side walls 562 lying opposite the surface sections 550 . The top surface 564 of the lens regions 560 is in turn likewise formed in the manner of a lens and has a slightly tapering depression or recess 566 , the bottom surface of which is curved. As can be seen particularly in the ray profiles represented in FIG. 6 c , these lens regions 560 also exert an influence, in the form of refraction and total internal reflection, on the light emitted by the associated light source 100 or 200 , although in contrast to the cooperative regions a lens region 560 influences exclusively the light of the respectively associated light source 100 , 200 . That is to say, as seen in sectional representation, the light directing element 500 alternately comprises lens regions 560 which influence exclusively the light of the associated light source 100 , 200 , and cooperative regions which influence the light of the two adjacent light sources 100 , 200 . As can furthermore be seen from the sectional representation of FIG. 6 c , the lower side of the light directing element 500 is provided with further angled surface regions and depressions in order to influence in the desired way the light emission which is finally achieved. A further lens element 560 , which influences exclusively the light of the light source 100 , 200 arranged above it, is also respectively provided in the region of a cavity in the exemplary embodiment of FIGS. 7 a to 7 c . One difference from the exemplary embodiment of FIGS. 6 a to 6 c is that in this case the top surface 564 of the lens region 560 is configured differently, namely having an essentially point-like central depression 568 to which the surface extends in a curved fashion from the circumference inward. Furthermore, the lens regions 560 are now not provided with a recess on the lower side but instead have a dome, or spherical cap-shaped outward curvature. This ultimately leads to a different influence on the light of the light sources 100 , 200 , although the central concept of the invention is still implemented, namely that owing to the cooperative regions bridging the adjacent cavities 505 very effective light mixing is achieved, and at the same time the light output characteristic can also be influenced in a desired way. The examples illustrate in particular the fact that, by corresponding configuration of the cavities or of the lens regions contained therein, as well as of the lower side of the light directing element, influence can be exerted very efficiently on the light output characteristic of the overall arrangement, or on the light distribution curve achievable with the arrangement. The solution according to the invention furthermore offers the possibility of advantageous manufacture or production of the light directing element 500 , or of an arrangement for emitting light. FIGS. 8 a to 8 d respectively show a light emission element 500 which is manufactured by a method according to the invention for producing a light directing element 500 . To this end, a light directing element 500 according to the invention, preferably configured in a planar fashion, is to be manufactured. For example, a transparent light directing element could be produced, preferably from PMMA, preferably by an injection-molding method. In a further step, the light directing element 500 is then to be shaped in such a way that the desired shape is obtained. For example, the light directing element 500 could be cut accordingly so that the wave-shaped, arc-shaped, or circular or donut-shaped light directing elements 500 represented in FIGS. 8 a to 8 d are obtained. Furthermore, for example, lines, rectangles, squares, steps or circles may also be envisioned as the basic shape of the light directing element 500 . In particular, easy adaptability of the desired light emission can be achieved in this way. Particularly preferably, a laser cutting method or another restricted local shaping method may be envisioned for this, in particular a melting or ablation method, which can significantly reduce corresponding tool costs. From the description above, it is clear that the invention significantly optimizes the possibilities of combining the light emission of a plurality of point light sources. The term bounding surface in the claims means a bounding surface or bounding surface section, formed on a light entry surface of the light directing member. Lastly, it should be pointed out that the combination of features of various exemplary embodiments or methods, or features disclosed in the figures, is included according to the invention.

An arrangement for outputting light is provided, having a plurality of punctiform light sources and a light deflection element with a boundary face and/or a boundary face section, which boundary face or boundary face section is arranged in the beam path of the light of both a first light source and of a second light source. In this context, the boundary face or the boundary face section forms a light input face for the light of the first light source into the light deflection element and at the same time forms a reflective face for the light of the second light source.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on, and claims benefit of, U.S. Provisional patent Application No. 61/313,172, filed Mar. 12, 2010, the entire contents of which are hereby incorporated herein by reference. MICROFICHE APPENDIX Not Applicable. TECHNICAL FIELD The present invention relates generally to optical communication systems, and in particular to a Shared Photonic Mesh network. BACKGROUND Today's Fibre optic transmission systems are employing recent advances in optical switching technology to provide reconfiguration at the optical layer. The networks created in the photonic domain have evolved from simple point-to-point and ring architectures to more arbitrary topologies. That is to say that it is possible to redirect the individual channels within a dense wavelength division multiplexed (DWDM) system onto different transmission fibres. This is what is commonly referred to as the photonic mesh architecture. One of the purported benefits of mesh architectures is the ability to more efficiently use network resources to provide resiliency. This is a well known benefit of internet protocol (IP) router architectures which lend themselves readily to such topologies. The corresponding increased reliance on more complex routing and switching nodes in the network drives more cost into these nodes. The increase in use of optical switching promises to alleviate some of this additional cost by eliminating the need for multiple transponder interfaces. It is also desirable to keep the signals in the optical domain for as much of their transit distance in the system because of the inherent power efficiency of optical components. Optical components have power dissipation several orders of magnitude smaller than the equivalent functions in the electronic domain. However; it is a practical reality that optical switching, especially those which are cost effective and low power, have switching speeds several orders of magnitude slower than their electrical counterparts. Therefore, although there is a potential savings in cost (both capital and energy), there is a penalty in the performance of such an entirely optical network in terms of reconfiguration speed. A motivation of this invention is to eliminate as many transponder interfaces as possible while maintaining overall system availability and keeping a low switching time for failure events. There are different types of failures which may lead to the need to reconfigure the network. It is possible to categorize these in two groups. The first is span failures (which include fibre cuts, line amplifier failures, etc.) which make a link between the routers unavailable. The second is equipment failures at the routing nodes which make individual ports on the nodes unavailable. The first type of failure tends to be the dominant one in most long haul networks. Two factors contribute to this fact. First, recent advances in transponder technology allow for the use of 1000's of km of fibre optic transmission in the optical domain with out the need for electrical regeneration. This elimination of electro-optical (EO) interfaces drives down the failures due to this equipment. In addition, network operators may find it difficult to repair broken fibres in some locations. Underwater cables are an example where it may take a long time for the fibre to be repaired in the case of a break. Also, it is costly to provide the level of service required to ensure a mean time to repair (MTTR) on fibre cable. It is much simpler to ensure a low MTTR for equipment located in the central office (CO). Prior to the introduction of photonic switches, all reconfiguration had to be performed in the electronic domain. FIG. 1 shows an example of a network 2 where all switching/routing nodes are interconnected in a mesh fashion. In the illustration of FIG. 1 , the network 2 is divided into an Internet Protocol/Multi-Protocol Label Switching (IP/MPLS) layer 4 and an optical transport layer 6 . The optical transport layer 6 comprises the physical infrastructure of the network, and comprises physical switching nodes 8 (such as, for example, Reconfigurable Optical Add/Drop Multiplexers (ROADMs)) interconnected by DWDM optical channels 10 routed through optical fiber links 12 . The IP/MPLS layer 4 comprises a respective router 14 for each physical switching node 8 of the optical transport layer 6 , and provides path computation and protection switching for traffic flows through the network 2 . Typically, each router provides electronic switching capacity between a set of client access ports (not shown) and a set of I/O ports connected to EO interfaces that transmit and receive optical signals through the optical transport layer 6 The IP/MPLS layer 4 typically represents each optical channel 10 as a connection 16 extending between a pair of electro-optical (EO) interfaces, and comprising working (W) and protection (P) transport capacity. For simplicity of illustration, each of the connections 16 corresponds with a respective fiber link 12 in the optical transport layer 6 . However, it will be appreciated that this will frequently not be the case. For example, consider an optical channel 10 that extends through the optical transport layer 6 between nodes A and E, which passes through node B without terminating. In this case, corresponding connection 16 in the IP/MPLS layer 4 would extend directly between router A and router E, and bypass router B. The IP/MPLS layer 4 ensures end to end survivability against all failures including optical layer equipment failures and network fiber cuts through the use of additional capacity. This “restoration capacity” is determined using off-line planning tools by running link failure analysis and/or engineered by keeping router trunk utilization below a threshold of 50%. The amount of restoration bandwidth determines the level of network survivability. This type of network uses the same mechanism to protect the system against both span and equipment failures. This is inefficient, since there are many more EO interfaces in place to protect against span failures than are needed for equipment redundancy, especially at high-degree nodes (those with more than two directions intersecting at them). Techniques which enable the elimination of as many transponder interfaces as possible while maintaining overall system flexibility and keeping a low switching time for reconfiguration events remain highly desirable. SUMMARY Accordingly, an aspect of the present invention provides a network element of an optical communications network. The network element comprises an electronic router for forwarding traffic between a set of client access ports and a plurality of I/O ports. A respective EO interface is coupled to each one of the plurality of I/O ports. Each EO interface terminates a respective optical channel. A directionally independent access (DIA) node is configured to selectively route each optical channel between its respective EO interface and a selected one of at least two optical fiber links of the optical communications network. BRIEF DESCRIPTION OF THE DRAWINGS Representative embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: FIG. 1 is a block diagram schematically illustrating elements of a communications network utilizing electronic traffic switching and optical transport, known in the art; FIG. 2 is a block diagram schematically illustrating elements of a communications network communications network utilizing electronic traffic switching and optical layer restoration, in accordance with a representative embodiment of the present invention; FIG. 3 is a block diagram schematically illustrating a first step in a protection/restoration process in accordance with a representative embodiment of the present invention, implemented in the network of FIG. 2 ; FIG. 4 is a block diagram schematically illustrating a second step in a protection/restoration process in accordance with a representative embodiment of the present invention, implemented in the network of FIG. 2 ; and FIG. 5 is a block diagram schematically illustrating elements of a directionally independent access node in accordance with a representative embodiment of the present invention usable in the embodiments of FIGS. 2-4 . It will be noted that throughout the appended drawings, like features are identified by like reference numerals. DETAILED DESCRIPTION In very general terms, the present invention provides methods and systems in which shared electro-optic (EO) interfaces and optical switching technology are used to create a resilient mesh network with a minimum of redundant EO interfaces. This is particularly effective in networks where span availability is a major contributor to the system unavailability. A first representative embodiment is shown in FIG. 2 . Each node includes a conventional electronic router, which in this case is augmented with a directionally independent access (DIA) node 18 that provides colourless directionally independent access for all of the channels terminating at that location. This arrangement is also compatible with a ROADM where wavelengths can be reconfigured when transiting the node. The DIA node 18 enables any optical channel 10 that terminates at the node to be routed through any fiber link 12 attached to the node. Therefore, it is not necessary for the node to have as many EO interfaces as there are channels supported by that node. Instead, the node can be configured with the minimum number of EO interfaces required to support client facing ports and to protect for router equipment failures. Span protection can be achieved by the optical reconfiguration of the DIA node 18 . This is a two step process. FIG. 3 shows how the first step in system recovery to a span failure. In the scenario of FIG. 3 , a span failure occurs on the fiber span we connecting nodes A and B in the Optical transport layer 6 , indicated by an X in the drawing. The span failure is detected by the routers 14 in the IP-MPLS layer as a connection failure affecting the connection 16 between the affected routers 14 a and 14 b . In response to the detected connection failure, the routers A and B implement a conventional protection switching operation to electronically switch the affected traffic to designated protection capacity in the connections AC and CB, using a protection path that is either predetermined or computed following detection of the failure. As a result, the affected traffic flows are re-routed to pass through router C, which restores the traffic flow between routers A and B while bypassing the failed connection 16 , and thus the failed fiber link 12 . As may be appreciated, this first switching event is handled entirely in the electronic domain (that is, in the IP/MPLS layer 4 ) which means that the system response time is very fast. However, the network is now in a state where it is vulnerable to a second failure, affecting either network equipment or a fiber span, which could cause an outage. Even without a second failure, the network links carrying the traffic switched from the failed link are now more heavily loaded, which leaves the network less resilient to peaks or bursts of traffic as are common to routed networks. The probability of a second failure occurring increases with the time spent in this condition. In the prior art, if the system doesn't have adequate additional bandwidth for multiple failures, one must take this time to be the MTTR for a span failure. On the other hand, this additional bandwidth drives cost in EO interfaces and in router/switch capacity. The present invention avoids this problem by re-routing the EO interface which was facing the failed direction (fiber span) onto another fibre direction through the reconfiguration of the DIA nodes 18 as may be seen in FIG. 4 . Thus, at nodes A and B, the EO interfaces that terminate optical channels 10 affected by the span failure are identified. The DIA nodes 18 a and 18 c are then reconfigured so that new optical channels can be set up between the identified EO interfaces, which traverse fiber links AC and CB, and pass through the DIA mode 18 c at node C. The EO interfaces may be re-tuned to new channel wavelengths, as required to support the new channels 10 . Once these new optical channels 10 have been set up and validated (in a conventional manner), they can be advertised to the IP/MPLS layer 4 a working connections between nodes A and B. As a result, routers 14 a and 14 b in the IP/MPLS layer recognise that the connection AB 16 has been restored, and so can switch the protection traffic back onto working transport capacity of that connection. One other interesting benefit of this approach, which should be evident from the FIGS. 3 and 4 , is that the network topology presented to the IP/MPLS layer 4 remains the same before and after restoration. This is because the re-routed channels 10 pass through DIA node 18 C without terminating at that node, and therefore appear as a direct connection 16 in the IP/MPLS layer 4 . Transport networks such as the type described above sometimes also have a sensitivity to the latency of the transport of data between the router ports which terminate any given connection. In some embodiments of the present invention there is provided a route calculation for the optical layer restoration, where the delay or latency is considered in the selection of the restoration path. In a system where the is a rich fibre interconnect and where there is an abundance of router bypass at the optical layer, there will often be photonic restoration paths which will have lower latency than the path that the data will take through the IP/MPLS restoration path. Thus, for example, a controller (which may be co-located with a node or at a central location, as desired) may compute two or more candidate routes through the optical transport layer 6 for the new channel, and estimate the latency for each route. based on this information, the controller may then select the best route (for example the route having the lowest latency) and set up the new channel over the selected route. This embodiment has the additional advantage of restoring not only the network to a pre-failure level of utilization and resiliancy, but it also restores it to a more comparable overall latency. The two step process outlined above is beneficial in that the electrical protection switching step provides a rapid response to network failures, and then the second step enables the restoration of the protection-switched traffic back onto working transport capacity that bypasses the failed span. While a second fiber span failure could cause an outage, the probability of such an event is very much lower than the probability of a failure affecting IP/MPLS layer network equipment (such as EO interfaces, routers etc.). Consequently, this approach yields a very low “effective MTTR” which can dramatically improve the availability of the network as a whole. FIG. 5 schematically illustrates a possible directionally independent access (DIA) node 18 usable in the present invention. In the embodiment of FIG. 5 , the DIA node 18 comprises a network of three Wavelength Selective Switches WSSs 20 , which are interconnected between a set of EO interfaces 22 , and two transmission fiber pairs defining respective bidirectional optical links 12 between the DIA node 18 and counterpart DIA nodes 18 connected to other nodes 8 of the network. Other configurations, which may provide interconnection to more than two transmission fibre pairs, are possible, and may be used, if desired. As may be seen in FIG. 5 , each WSS 20 includes a common-IN port 24 , a common-OUT port 26 and set of m switch ports 28 . Each switch port 28 comprises an Add port 28 a and a Drop port 28 b . In operation, the WSS 20 is designed to selectively switch any wavelength channel from the common-IN port to the Drop port of any one of the switch ports 28 , and to selectively switch any wavelength channel received through the Add port of any given switch port 28 to either the common-OUT port 26 or to the Drop port of any one of the other switch ports 28 . In the DIA node 18 of FIG. 5 , a first WSS 20 a hosts a set of EO interfaces 22 which terminate optical channels 10 being added or dropped at the node 8 , and selectively switches these channels to the two branch Wavelength Selective Switches 20 b and 20 c , each of which is connected to a respective transmission fiber pair 12 . With this arrangement, a wavelength channel received by one branch WSS (say, WSS 20 b ) through its common-IN port 24 , can be selectively switched to either: the first WSS 20 a , which can then switch the received channel through to a local OE interface 22 ; or the other branch WSS 20 c , which can then switch the received channel through to its common-OUT port 26 for transmission to a neighbour node of the network. Conversely, a wavelength channel received by the first WSS 20 a from a local OE interface 22 can be selectively switched to either one of the branch WSSs 20 b , 20 c , which can then switch the received channel through to its common-OUT port. 26 . for transmission to a neighbour node of the network. In the embodiment of FIG. 5 , the operation of the first WSS 20 a and the local OE interfaces 22 is colourless, as described in Applicant's International patent application Serial No. PCT/CA2009/001455. Thus, in the illustrated embodiment, the common out port 26 is connected to a 1:n power splitter 30 , which receives a set of dropped wavelength channels from the first WSS 20 a and supplies these channels to each one of a corresponding set of s coherent receivers (cRx) 22 r . Each coherent receiver (cRx) is preferably tuneable, so that it can receive a wavelength channel signal centered a desired carrier wavelength (or frequency). In some embodiments in which tuneable coherent receivers are used, the frequency range of each receiver 22 r may be wide enough to enable the receiver to tune in any channel of the network. In other embodiments, the dynamic range of each receiver 22 r may be wide enough to enable the receiver to tune in any one of a subset of channels of the network. In still other embodiments, each receiver may be non-tuneable. Each coherent receiver 22 r must be designed having a CMRR which enables the receiver to tune in and receive a selected one channel while rejecting each of the other channels presented to it. Conversely, a 1:n power combiner 32 is used to combine channel signals generated by a respective set of transmitters (Tx) 22 t , and supply the resulting wavelength division multiplexed (WDM) signal to the common in port 24 of WSS 20 a . Preferably, each transmitter (Tx) 22 t is tuneable, so that it can generate a wavelength channel signal centered on a desired carrier wavelength (or frequency). In some embodiments in which tuneable transmitters are used, the dynamic range of each transmitter (Tx) 22 t may be wide enough to enable the transmitter (Tx) 22 t to generate any channel of the network. In other embodiments, the dynamic range of each transmitter (Tx) 22 t may be wide enough to enable the transmitter (Tx) t 22 to generate any one of a subset of channels of the network. In still other embodiments, each transmitter (Tx) 22 t may be non-tuneable. It should be noted that while only a single set of 1:n power splitters and combiners is described herein, there are other embodiments with combinations of WSS stages combined with power splitter and combiner stages which can support more channels in a colorless fashion, the details of which are described in the referenced international patent application. As noted above, in the embodiment of FIG. 5 , the EO interfaces 22 are connected to the common-IN and common-OUT port 26 , 24 if the first WSS 20 a . However, it will be appreciated that this is not essential. In fact, those of ordinary skill in the art will recognise that EO interfaces 22 may be connected to one or more of the switch ports 28 , either alone or in combination with EO interfaces 22 connected to the common ports 24 and 26 . In the foregoing description, the present invention is described with reference to a representative embodiment in which electronic traffic routing functionality is provided by an IP/MPLS layer. However, it will be appreciated that this is not essential. In fact, the techniques of the present invention can be implemented in any network in which a connection-oriented electronic traffic routing layer is over-laid on an optical transport layer. Thus, for example, in alternative embodiments, the electronic traffic routing layer may be implemented using an Ethernet technology, without departing from the scope of the present invention. Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the claims appended hereto.

A network element of an optical communications network. The network element comprises an electronic router for forwarding traffic between a set of client access ports and a plurality of I/O ports. A respective EO interface is coupled to each one of the plurality of I/O ports. Each EO interface terminates a respective optical channel. A directionally independent access (DIA) node is configured to selectively route each optical channel between its respective EO interface and a selected one of at least two optical fiber links of the optical communications network.

CROSS REFERENCES TO RELATED CO-PENDING APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 09/491,722, filed Jan. 27, 2000 now U.S. Pat. No. 6,213,966 which is a continuation of U.S. patent application Ser. No. 09/271,822, filed Mar. 18, 1999, now U.S. Pat. No. 6,113,561, which is a divisional of U.S. patent application Ser. No. 08/786,713, filed Jan. 21, 1997, now U.S. Pat. No. 5,964,723, which is a continuation-in-part U.S. patent application Ser. No. 08/356,325, filed Feb. 21, 1995, now abandoned, which is a 35 U.S.C. 371 priority application of PCT International Application Ser. No. PCT/US93/05876, filed Jun. 18, 1993, which is a continuation-in-part of, and claims priority from, U.S. patent application Ser. No. 07/900,656, filed Jun. 19, 1992, now abandoned. This application is related to U.S. patent application Ser. No. 08/785,794, filed Jan. 21, 1997, now U.S. Pat. No. 5,986,163, and U.S. patent application Ser. No. 08/786,714, file Jan. 21, 1997, now U.S. Pat. No. 5,954,680. FIELD OF THE INVENTION This invention relates to a wound covering for wound treatment and, in particular, wound covers having a substantial portion of the wound cover in non-contact with the wound and capable of delivering heat to the wound. The wound covering preferably controls the temperature, humidity and other aspects of the environment at the wound site. BACKGROUND OF THE INVENTION Wounds in general, as used in this context, are breaks in the integrity of the skin of a patient. Wounds may occur by several different mechanisms. One such mechanism is through mechanical traumatic means such as cuts, tears, and abrasions. There are many instruments of causality for mechanical wounds, including a kitchen bread knife, broken glass gravel on the street, or a surgeon's scalpel. A different mechanism cause for mechanical wounds is the variable combination of heat and pressure, when the heat alone is insufficient to cause an outright burn. Such wounds that result are collectively referred to as pressure sores, decubitus ulcers, or bed sores, and reflect a mechanical injury that is more chronic in nature. Another type of mechanism causing a wound is vascular in origin, either arterial or venous. The blood flow through the affected region is altered sufficiently to cause secondary weakening of the tissues which eventually disrupt, forming a wound. In the case of arterial causes, the primary difficulty is getting oxygenated blood to the affected area. For venous causes, the primary difficulty is fluid congestion to the affected area which backs up, decreasing the flow of oxygenated blood. Because these wounds represent the skin manifestation of other underlying chronic disease processes, for example, atherosclerotic vascular disease, congestive heart failure, and diabetes, these vascular injuries also are chronic in nature, forming wounds with ulcerated bases. Traditional wound coverings, such as bandages, are used to mechanically cover and assist in closing wounds. Such bandages typically cover the wound in direct contact with the wound. This may be acceptable for acute, non-infected traumatic wounds, but it must be kept in mind that direct bandage contact with a wound can interfere with the healing process. This interference is particularly prevalent for chronic ulcerated wounds because of the repeated mechanical impact and interaction of the bandage with the fragile, pressure sensitive tissues within the wound. The benefits of application of heat to a wound are known, and documented benefits include: increased cutaneous and subcutaneous blood flow; increased oxygen partial pressure at the wound site; and increased immune system functions, both humoral and cell mediated, including increased migration of white blood cells and fibroblasts to the site. However, heat therapy for the treatment of wounds, either infected or clean, has been difficult to achieve in practice. For instance, heating lamps have been used, but these resulted in drying of wounds, and in some cases, even burning tissue from the high heat. Due to these and other difficulties, and since most acute wounds usually heal over time, physicians no longer consider the application of heat to the wound as part of the treatment process. The thinking among medical personnel is that any interference in a natural process should be minimized until it is probable that the natural process is going to fail. Additionally, the availability of antibiotics for use in association with infected wounds has taken precedence over other therapies for the treatment of chronic wounds and topical infections. In French patent number 1,527,887 issued Apr. 29, 1968 to Veilhan there is disclosed a covering with a rigid oval dome, its edge resting directly on the patient's skin. One aspect of the Veilhan wound protector is a single oval heating element resting on the outer surface of the rigid dome, positioned at the periphery of the rigid dome. Veilhan does not discuss the heating aspect other than to state that it is a component. The benefit of controlling other environmental parameters around the wound site are not as well known. Control the humidity at the wound site and the benefits of isolating the wound have not been extensively studied and documented. While the benefit of applying heat to wounds is generally known, the manner of how that heat should be used or applied is not known. Historically, heat was applied at higher temperatures with the goal of making the wound hyperthermic. These higher temperatures often resulted in increasing tissue damage rather than their intended purpose of wound therapy and healing. There is a need for appropriate wound care management incorporating a heating regimen that is conducive to wound healing, yet safe and cost effective. SUMMARY OF THE INVENTION The present invention disclosed herein approaches the treatment of wounds with heat based on an understanding of physiology. The normal core temperature of the human body, defined herein for purposes of this disclosure, is 37° C.±1° C. (36°-38° C.), which represents the normal range of core temperatures for the human population. For purposes of discussion and this disclosure, normal core temperature is the same as normothermia. Depending on the environmental ambient temperature, insulative clothing and location on the body, skin temperature typically ranges between about 32° C. and about 37° C. From a physiologic point of view, a 32° C. skin temperature of the healthy distal leg is moderate hypothermia. The skin of the distal leg of a patient with vascular insufficiency may be as low as 25° C. under normal conditions, which is severe hypothermia. A fundamental physiologic premise is that all cellular physiologic functions, biochemical and enzymatic reactions in the human body are optimal at normal body core temperature. The importance of this premise is seen in how tightly core temperature is regulated. Normal thermoregulatory responses occur when the core temperature changes as little as ±0.1° C. However, the skin, as noted above, is usually hypothermic to varying degrees. For example, the skin of the torso is usually only slightly hypothermic, whereas the skin of the lower legs is always hypothermic. Consequently, wounds and ulcers of the skin, regardless of location, are usually hypothermic. This skin hypothermia slows cellular functions and biochemical reactions, inhibiting wound healing. The effects of hypothermia on healing are well known. A number of regulatory systems with a human are affected, such as the immune system and coagulation, with both platelet function as well as the clotting cascade affected. Patients with hypothermic wounds experience more infections which are more difficult to treat, have increased bleeding times and have been shown to require more transfusions of blood. All of these complications increase morbidity and the cost of patient care and, to a lesser extent, increase the likelihood of mortality. One purpose of the present invention is to raise the wound tissue and/or periwound tissue temperatures toward normothermia to promote a more optimal healing environment. The present invention is not a “heating therapy”, per se, where it is the intent of “heating therapy” to heat the tissue above normothermia to hyperthermia levels. Rather, the present invention is intended to bring the wound and periwound tissues toward normothermia without exceeding normothermia. The medical community has not historically considered normothermic heating to be therapeutic. Many physicians feel that hypothermia is protective and, therefore, desirable. Studies with the present invention would indicate that this widely held belief that hypothermia is at least benign or possibly beneficial incorrect with regard to wound healing. The present invention is a wound covering for application to a selected treatment area of a patient's body that includes, at least as a portion of the selected treatment area, a target tissue of a selected wound area. The selected treatment area may also include a portion of the area immediately proximate to the wound area referred to as the periwound area. The wound covering comprises a heater suitable for providing heat to at least a portion of the selected treatment area, an attachment for attaching the heater in a non-contact position proximate the selected treatment area, a heater controller, connected to the heater and including a power source for the heater, for controlling the heater, and an input control to the heater controller providing guidance to the heater controller so as to heat the wound and/or periwound tissue to a temperature in a range from a pretreatment temperature to about 38° C. Pretreatment temperature is that temperature the wound tissue is at when therapy begins and is usually somewhat above ambient temperature and also is variably dependent on where the wound is located on a patient's body skin surface. The ambient temperature is that temperature of the environment immediately around the selected treatment area not a part of the patient's body, i.e., the bed, the air in the room, the patient's clothing. The heater is selectable from among several types of heat sources such as warmed gases directed over the selected treatment area and electrical heater arrays placed proximate the selected treatment area. Electrical heater arrays are adaptable for construction into a layer of variable proportion and geometry or as a point source. The present invention anticipates the ability to provide several different sizes and geometric configurations for the heater. The present invention is flexible in being able to provide uniform heating over the entire selected treatment area or provide a non-uniform heating distribution over selected portions of the selected treatment area. Alternate heat source embodiments could include warm water pads, exothermic chemical heating pads, phase-change salt pads, or other heat source materials. The present invention anticipates that the controller is able to control both the temperature and the duration of the application of heat. This control may extend from manual to fully automatic. Manual control anticipates the controller maintaining the heater temperature at an operator-selected temperature for as long as the operator leaves the heater on. More automatic modes provide the operator an ability to enter duty cycles, to set operating temperatures, as well as to define therapy cycles and therapeutic sequences. As used herein, a duty cycle is a single on cycle when heating of the heater is occurring, measured from the beginning of the on cycle to the end of that on cycle. A heater cycle is a single complete on/off cycle measured from the beginning of a duty cycle to the beginning of the next duty cycle. Consequently, a duty cycle may also be represented in a percentage of, or as a ratio of the time on over the time off. A plurality of heater cycles are used to maintain heater temperature around a selectable temperature set point during a therapy cycle which is defined as an “on” period, composed of a plurality of heater cycles, and an “off” period equivalent to remaining off for an extended period of time. A therapeutic sequence, as used herein, is a longer period of time usually involving a plurality of therapy cycles spread out over an extended period of time, the most obvious being a day in length. The present invention anticipates the use of any period of time as a therapeutic sequence and involving one, or more than one therapy cycles. The present invention also anticipates programmability for a number of modalities including peak heater temperature for a duty cycle and/or therapy cycle, average heater temperature for a duty cycle and/or therapy cycle, minimum heater temperature for a heater cycle and/or therapy cycle, ratio of duty cycle, length of therapy cycle, number of duty cycles within a therapy cycle, and number of therapy cycles in a therapeutic sequence. Different duty cycles within a therapy cycle may be programmed to have different peak heater temperatures and/or heater cycles may have average heater temperatures over that therapy cycle. Different therapy cycles within a therapeutic sequence may be programmed to have different peak heater temperatures and/or average heater temperatures over each therapy cycle. The wound covering control is operator-programmable or may have preprogrammed duty cycles, therapy cycles, and therapeutic sequences selectable by the operator. The input control may take several forms. One form of input control is a temperature feedback from a temperature sensor placed proximate the selected area of treatment to monitor the target tissue temperature response. The sensor provides to the input control, a sequence of temperature values for the target tissue of the selected treatment area. Programmability may provide for variable heater output dependent on the actual target tissue temperature as well as the rate of target tissue temperature change within the selected treatment area. Another form of input control is for the controller of the present invention to follow a temperature treatment paradigm programmable within the controller which is based on one or more parameters derived empirically, such as: the thermodynamic characteristic of tissue, the heat conduction rate of tissue types, the wound location, the wound type, the wound stage, the wound blood flow, the tissue surface area involved in the selected treatment area, the tissue volume involved in the selected treatment area, the heater geometry, the heater output, the heater surface area, and the ambient temperature. This paradigm programming provides an operator the ability, when selecting a treatment mode or method, to take into account all of these parameters. More importantly, the operator is able to tailor a treatment mode based on the type of wound to be treated. For example, wound types, such as wounds secondary to arterial insufficiency verse those secondary to venous insufficiency, or the location of the tissue on the body, for example, the leg versus the sacrum or abdomen, are sufficiently different so as to necessitate different heater treatment methods that take into account the myriad number of differences between wound types. One or more parameters are inputted to the controller to provide a sequence of target tissue temperatures over time to the heater controller based on the parameters used. A preferred form of the wound covering includes an attachment as a peripheral sealing ring which, in use, completely surrounds the area of the wound and periwound, i.e., the selected treatment area. The upper surface of the peripheral sealing ring is spanned by a continuous layer which is preferably transparent and substantially impermeable, although the present invention also anticipates the use of a gas permeable layer suitable for some applications. Once in position, the sealing ring and the layer define a wound treatment volume which surrounds the wound. Additionally, the layer spanning the peripheral sealing ring maybe sealed about the periphery of the sealing ring and act as a barrier layer over the wound treatment volume. Optionally, the heater may be incorporated into the barrier layer or the barrier layer may be incorporated into the heater. An adhesive and a suitable release liner is applied to the lower surface of the peripheral sealing ring to facilitate the application of the wound covering to the patient's skin. The barrier layer may include a pocket adapted to receive an active heater. An alternate form of the invention provides for the transport of heated air from a remote heat source to the wound treatment volume. In the active heater embodiments a thermostat and/or a pressure-activated switch may be used to control the heating effects of the heater. Passively heated embodiments are contemplated as well. These passive versions of the device include the use of thermally insulating coverings which retain body heat within the treatment volume. These reflectors or insulators may be placed in a pocket formed in the barrier layer. Each of these heated embodiments promote wound healing by maintaining the wound site at a generally elevated, but controlled, temperature. In general, the peripheral sealing ring is made from an absorbent material which may act as a reservoir to retain and/or dispense moisture into the treatment volume increasing the humidity at the wound site. The reservoir may also contain and deliver medicaments and the like to promote healing. The present invention is designed to directly elevate the temperature of the hypothermic skin and subcutaneous tissue of the selected wound area to a temperature which is close to or at normothermia. The purpose of this device is to create within the wound and periwound tissues of the selected treatment area a more normal physiologic condition, specifically a more normothermic condition, which is conducive to better wound healing. The present invention anticipates the use of an active heater that creates a heat gradient from heater to wound and periwound tissues. The usual temperature gradient for tissues goes to about 37° C. deep in the body core down to about 32° C. at the skin surface of the leg. The heater of the present invention operates in an output range suitable to raise the temperature of the selected treatment tissue from its pretreatment temperature to not more than 38° C. In contrast, typical local heating therapy (e.g. hot water bottles, hot water pads, chemical warmers, infrared lamps) deliver temperatures greater than 46° C. to the skin. The goal of traditional heating therapy is to heat the tissue above normal, to hyperthermic temperatures. The present invention differs from infrared lamps two ways. First, the present invention includes a dome over the wound that is relatively impermeable to water vapor transmission. After application of the bandage, moisture from the intact skin or wound evaporates, and air within the dome quickly reaches 100% relative humidity. The interior of the present invention is now warm and humid. For example, a 2.5 square inch bandage at 28° C. requires only 0.0014 g of water to reach saturation. When the air is thus saturated, no further evaporation can occur and, therefore, no drying of the wound can occur. This equilibrium will be maintained as long as the bandage is attached to the patient. When heat is provided by the preferred embodiment of the present invention, the absolute amount of water needed to reach 100% relative humidity is slightly increased since warm air has a greater capacity for holding moisture. However, the air within the dome of the bandage still reaches water vapor saturation very quickly, and no further evaporation occurs. For example, a 2.5 square inch bandage of the present invention at 38° C. requires only 0.0024 g of water to reach saturation. Excess moisture is absorbed by the foam ring, but still is retained within the bandage. The enclosed dome design maintains 100% humidity over the wound which also prevents evaporation due to the heat. As long as the humidity is retained within the bandage, heating therapy could theoretically be continued indefinitely without causing the wound to dry. In contrast, when using infrared lamps, the wounds are open and exposed to the environment. The result is excessive drying of the wound, increasing tissue damage. Secondly, the present invention operates at low temperatures, from above ambient to about 38° C. This causes only minimal heating of the skin. In contrast, infrared lamps operate at temperatures in excess of 200° C. These lamps heat the wound to hyperthermic temperatures which can cause thermal damage to the tissue of the wound. At the low (normothermic) opening temperatures of the present invention, the heat transfer to the skin is minimal. The low wattage heater, the inefficiencies of the heat transfer into the tissue, the thermal mass of the tissue and the blood flow (even if markedly reduced), all prevent the wound temperature from reaching the heater temperature. Hypothermic wound tissue is warmed as a result of “migration” of the body's core temperature zone toward the local wound area. The following data document the tissue temperatures resulting from a 38° C. heater of the present invention on: Average Maximum Normally perfused human skin 36° C. 36° C. Arterial/diabetic foot ulcers 32° C. 35° C. Venous/arterial leg/foot ulcers 33° C. 35° C. Non-perfused human model 35° C. 35° C. When warmed with a 38° C. heater, wounds on poorly perfused legs reach stable average temperatures of 32-33° C. In contrast, normally perfused skin reaches 36° C. It is important to note that these data are contradictory to the assumption that poorly perfused tissue would reach a higher temperature than normally perfused tissue. This result substantiates the physiologic finding that the “migration” of the core temperature zone toward the local wound zone, decreasing the gradient difference between the core and surface temperatures, is the cause for the observed increase wound temperatures. Core temperature regulation is heavily dependent on perfusion, and migration of the core temperature zone is also heavily dependent on perfusion. At no point in time did the poorly perfused tissue reach normothermia. Consequently, poorly perfused legs are much colder than normally perfused legs, and, thus, poorly perfused legs constitute a substantially deeper heat-sink. A wound-healing pilot study is under way, studying patients with chronic arterial and/or venous ulcers of the lower leg. These patients have suffered from these ulcers for many months and, in some cases, even years, despite aggressive medical and surgical therapy. Of 29 patients enrolled, 24 have completed the study protocol or are still being treated. Of these 24 patients, 29% are completely healed, and 38% show a significant reduction of the wound size within 2-5 weeks of receiving therapy with the present invention. A known consequence of restoring normothermia to tissues is to induce some degree of vasodilatation which increases local blood flow. Preliminary data collected during trials of the present invention, studying the effects of the present invention on normal subjects and on wound healing, has borne this out. An added effect has been to increase the partial pressure of oxygen in the subcutaneous tissues (P sq O 2 ), which is an indirect indicator of the status of the tissue. The higher the P sq O 2 , the greater the likelihood the tissue will benefit and improve the healing process. The results of some of these studies are presented in Tables 1-4. In conducting the studies presented in Tables 1-4, a wound covering according to the present invention is placed over the skin. The temperature of the subcutaneous tissue is then measured over time. From −60 minutes to the 0 minute mark, the heater is off in order to obtain a baseline temperature. At the 0 minute mark the heater is activated and its temperature kept constant over the next 120 minutes when it is turned off. Temperature measurements were taken during this 120 minute period and for an additional 180 minutes after turning the heater off. As shown in Table 1, with activation of the heater to 38° C., the subcutaneous tissue temperature rapidly rose from about 34.3° C. to about 36° C. over the first 30 minutes. The temperature of the subcutaneous tissue continued to slowly raise over the next 90 minutes to a temperature of about 36.7° C. After turning the heater off, the temperature of the subcutaneous tissue fell to about 35.9° C. and held this temperature fairy uniformly for at least the next 120 minutes. Table 2 presents the skin temperature data collected from within the wound cover of the present invention for the same periods as those in Table 1. The general curve shape is similar to the subcutaneous tissue temperature curve. The baseline temperature at the 0 minute mark was about 33.5° C. After turning the heater on to 38° C., the skin temperature rose rapidly to about 35.8° C. in the first 30 minutes, then slowly rose to about 36.2° C. by the end of the 120 minute heating period. After turning the heater off, the skin temperature fell to about 35° C. and held there for at least the next two hours. Table 3 represents laser Doppler data collected from the tissue during the experiments and correlates to blood flow through the local area being treated with heat. The baseline flow is approximately 80 ml/100 g/min and rises to about 200 ml/100 g/min at its peak, half way through the heating period. The flow “normalizes” back to baseline during the last half of the heating period and remains at about baseline for the remainder of the measuring period. The change in P sq O 2 is followed in Table 4. The baseline P sq O 2 is about 75 when heating begins and rises steadily to about 130 by the end of the heating period. The P sq O 2 remains at this level for the remainder of the measuring period despite the lack of heating for the last 180 minutes. The added benefit of increased P sq O 2 by heating continues well into the period of time after active heating has ceased. Wounds will continue to benefit from the effects of heating for substantial periods of time after the heating is turned off. The consequences of this study with the present invention is that the heating need not be constant, but deliverable over a heater therapy cycle or cycles that may or may not be part of a larger therapeutic sequence. Similar trials were conducted using a heater temperature of 46° C. This data is presented in tables 5-8. Only slight additional benefits were found in any of the four measured parameters when studied at this higher temperature. The benefits imparted by active heating according to the present invention seem to peak at about 46° C. In many instances, 43° C. appears to be the optimal temperature for maximal efficiency in terms of least energy required for the greatest therapeutic gain. Our initial human clinical data shows that the beneficial effects of heating on blood flow and P sq O 2 last at least one hour longer than the actual duration of heat application. Further, we have noted that cycled heating seems to be more effective for wound healing than continuous heating. Therefore, the data recommends cycling the heater in a therapy cycle (e.g. 1 hour “on” and 1 hour “off”) for a total heating time of 2-8 hours per day as a therapeutic sequence. None of the 29 patients with compromised circulation treated to date have shown any indication of skin damage due to 38° C. heat. Furthermore, none of these wounds have exceeded 35° C. tissue temperature, with an average wound temperature of 32-33° C. The present invention raises the wound temperature toward normothermia, but even on a poorly perfused leg, the tissue does not reach normothermia. BRIEF DESCRIPTION OF THE DRAWINGS Illustrative but not limiting embodiments of the invention are shown in the attached drawings. Throughout the several figures like reference numerals refer to identical structure throughout, in which: FIG. 1A is an exploded view of a wound covering according to the present invention; FIG. 1B illustrates an assembled view of the wound covering of FIG. 1A; FIG. 2A is a view of an alternate wound covering; FIG. 2B is a view of an alternate wound covering of FIG. 2A with passive heating card inserted in the wound covering; FIG. 3A is an exploded view of an additional alternate wound covering; FIG. 3B is an assembled view of the wound covering of FIG. 3A; FIG. 4 is a side elevation view of a wound covering; FIG. 5 is an enlarged top plan view of a wound covering; FIG. 6 is an enlarged sectional view taken along line 6 — 6 of FIG. 5; FIG. 7 is a bottom view of the wound covering of FIG. 4; FIG. 8A is an exploded view of an alternate wound covering: FIG. 8B is an assembly view showing the air flow through the wound covering; FIG. 9A is a perspective view of an alternate wound covering; FIG. 9B is a side view of the wound covering of FIG. 9A; FIG. 10 is a perspective view of an alternate wound covering; FIG. 11A is a perspective view of an alternate wound covering; FIG. 11B is a side elevational view of the wound covering of FIG. 11A; FIG. 11C is a view of the wound covering of FIG. 11A; FIG. 12 is a perspective view of an alternate connector apparatus for the wound covering; FIG. 13A is an alternate connector arrangement for the wound covering; FIG. 13B is a side sectional view of the wound covering of FIG. 13A; FIG. 14 is a view of a rigid connector for engagement with a wound covering; FIG. 15 is an alternate fluid inlet line for the wound covering; FIG. 16A is a view of a two ply barrier layer wound covering; FIG. 16B is a side elevational view of the wound covering of FIG. 16A; FIG. 17 is an alternate wound covering; FIG. 18A is an alternate wound covering; FIG. 18B is a side sectional view of the wound covering of FIG. 18A; FIG. 19 is a side elevational view of an alternate wound covering FIG. 20 is a schematic diagram of an embodiment of the present invention; and FIG. 21A is a schematic representation of an alternate embodiment of the heater array distribution shown in FIG. 20; FIG. 21B is a schematic representation of an alternate embodiment of the heater array distribution shown in FIGS. 20 and 21A; FIG. 21C is a schematic representation of an alternate embodiment of the heater array distribution shown in FIGS. 20, 21 A, and 21 B; FIG. 21D is a schematic representation of an alternate embodiment of the heater array distribution shown in FIGS. 20, 21 A, 21 B, and 21 C; FIG. 22 is a graphical representative sample of an operational scheme for an embodiment of the present invention, such as the embodiment shown in FIG. 20; FIG. 23 is a graphical representative sample of an additional operational scheme for an embodiment of the present invention, such as the embodiment shown in FIG. 20 using the scheme depicted in FIG. 22; and FIG. 24 is a graphical representative sample of another additional operational scheme for an embodiment of the present invention, such as the embodiment shown in FIG. 20 using the schemes depicted in FIGS. 22 and 23 . DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a non-contact wound covering for controlling the local environment at a wound site on a patient. A wound site includes those portions of the patient's skin obviously definable as the wound area and the immediately adjacent periwound area as the selected treatment area of the wound site. The wound covering protects the wound from contamination by materials from the outside environment and also prevents the wound site from shedding contaminants into the local environment of the patient, i.e. the hospital room. The treatment volume formed proximate the wound site can be controlled to create an optimal healing environment. The word “wound” as used herein refers generically to surgical incisions, ulcers, or other lesions or breaks in the skin. First, a substantially vertical wall is provided to encircle the selected treatment area on the surface of the patient's skin. This vertical wall provides an upper surface to support a layer spanning this structure above the level of the wound and a lower surface suitable for attachment to the patient's skin. This structure is referred to throughout as an attachment or a peripheral sealing ring. Together these elements form a wound treatment volume between the layer and the surface of the selected treatment area. The fact that the layer does not contact the wound itself promotes healing by minimizing mechanical stresses on the tissues. The lower surface suitable for attaching to the skin may include an adhesive and a complimentary release liner assembly to facilitate the attachment of the wound covering to the skin of the patient. The present invention anticipates using a heater such that the layer may comprise the heater formed as the layer or as a layer which includes a heater within some portion of the layer. The layer may also include functioning as a barrier layer completely enclosing the wound treatment volume. In accordance with the present invention, the climate within the wound treatment volume may be controlled. Typically the temperature, humidity, and gas composition, for example adding oxygen, nitric oxide or ozone, are controlled. Also, aerosolized medications or compounds may be released into this volume as well. The above list is exemplary of the climate controls which may promote healing of the wound, and is not intended to limit the scope of the present invention. It will be understood by those skilled in the art that numerous other climate factors can be controlled within the treatment volume of the present wound covering system without departing from the scope of the invention. FIG. 1A illustrates an exploded view of a wound covering 50 . In this embodiment, a peripheral sealing ring 52 is substantially square in outline. Peripheral sealing ring 52 is intended to be attached to uninjured skin surrounding a selected treatment area 54 using an adhesive 56 . In this embodiment, a layer of adhesive hydrogel is shown as the adhesive 56 . Additionally, peripheral sealing ring 52 is preferably constructed of an open cell hydrophilic foam plastic having a sealed outer surface 58 which isolates the wound from the environment. The peripheral sealing ring is fabricated from a material which may conform to the curved surface of the patient's body. An inner surface 60 of sealing ring 52 is preferably porous or absorbent so that it can form a reservoir to contain and release moisture or water vapor into the air within a treatment volume 62 to create a high humidity environment if desired. Additionally, the hydrophilic absorbent nature of peripheral sealing ring 52 absorbs fluids and blood weeping from the wound. A layer 64 is preferably attached to an upper surface 66 of peripheral sealing ring 52 as a barrier layer to seal treatment volume 62 . Layer 64 is preferably constructed of a flexible synthetic polymeric film, such as polyethylene, polyvinyl chloride, polyurethane, or polypropylene. Additionally, other polymeric films, natural and semi-synthetic, that are suitable for use in medical applications such as cellulose and cellulose acetate, may be used. A wound tracing grid 68 , also constructed of a substantially clear flexible material, may optionally be used as, or attached to, layer 64 to facilitate wound care management so that the physician can draw an outline of the wound as an aid to tracking the healing process of the wound. The wound tracing grid preferably contains a labeling area 70 for identifying the patient, date when the wound was traced, and other patient medical data. It will be understood by those skilled in the art that the volume of peripheral sealing ring 52 will depend on the structural strength of the support material and the amount of fluid absorption desired. Additionally, the total area of peripheral sealing ring 52 is dependent on the size of the wound. For example, larger wounds and more flexible covers will require a thicker sealing ring so that the center of the cover does not touch the wound. Upper surface 66 of peripheral ring 52 is preferably sealed by extending barrier layer 64 over the entire area of upper surface 66 as shown in FIGS. 1A and 1B. Adhesive 56 for attaching peripheral sealing ring 52 to uninjured skin surrounding selected treatment area 54 may take any form, however, the preferred adhesive is preferably a two-faced hydrogel which attaches to a lower surface 72 of peripheral sealing ring 52 . This adhesive 56 permits the attachment of peripheral sealing ring 52 to the patient's skin. Finally, peripheral sealing ring 52 may serve as a reservoir for retaining water or medicaments in treatment volume 62 in order to maintain a high humidity in the air within the volume. Water may be added to peripheral sealing ring 52 at any time during treatment. It will be understood by those skilled in the art that peripheral sealing ring 52 can be supplied in a variety of shapes and sizes to accommodate various wounds. The shapes may include circles, squares, or rectangles. Although it is preferred to dispense the wound covering as a unitary assembly it should be apparent that individual segments of peripheral ring material could be assembled into any shape necessary to form a perimeter around the wound area. Likewise barrier layer 64 and wound tracing grid 68 could be provided in large sheets which may be cut to size and then attached to the peripheral sealing ring. FIG. 1B is an assembled view of wound covering 50 of FIG. 1 A. To dispense the assembled product, a release liner 74 of FIG. 1B is applied to adhesive 56 in FIG. 1 A. Release liner 74 may span the entire lower surface of the covering to maintain the sterility of treatment volume 62 . Release liner 74 preferably has a grip tab 76 to facilitate removal of release liner 74 from wound covering 50 immediately prior to application of wound covering 50 to the skin of a patient. FIGS. 2A and 2B illustrate an alternate embodiment of the present invention as a wound covering 80 utilizing passive heating of the treatment volume 62 . Because heat is constantly being radiated from the patient's skin surface, the insulation properties of the trapped air within treatment volume 62 will reduce this heat loss. By adding an infrared reflector 82 over treatment volume 62 , the infrared heat from the body can be reflected back to the skin for added passive heating. An edge 84 of wound tracing grid 86 is preferably not attached to the barrier layer to form an envelope or a pocket 94 between the wound tracing grid 86 and the barrier layer. A piece of reflective foil material 88 may be inserted into pocket 94 . A thin layer of insulating material 90 may be optionally attached to foil layer 88 to enhance heat retention and to provide foil layer 88 with additional resiliency. A tab 92 is preferably attached to infrared reflector 82 to allow easy insertion and removal from pocket 94 and wound covering 80 . FIGS. 3A and 3B illustrate a preferred alternate embodiment of a non-contact wound covering 108 utilizing active heating of a treatment volume 112 . Wounds may be safely and easily heated utilizing a heater assembly 100 . Heater assembly 100 alternatively comprises a pressure-sensitive switch 102 , an insulating layer 104 , and a foil heater 106 . Pressure-sensitive switch 102 is optionally laminated to the upper surface of heater assembly 100 . The purpose of switch 102 is to shut off power to foil heater 106 in the event that external pressure is applied to wound covering 108 with sufficient force to cause foil heater 106 to contact the skin or wound below. This feature prevents the possibility of applying heat and pressure to the skin at the same time. The combination of heat and pressure is known to cause burns even at low temperatures (40° C.) because the pressure prevents blood flow in the skin making it susceptible to thermal injury. Pressure-sensitive switch 102 preferably covers the entire area of heater assembly 100 so that pressure applied anywhere to the surface of heater assembly 100 will deactivate foil heater 106 . It will be understood by those skilled in the art that a variety of devices are suitable for use as pressure-sensitive switch 102 . Force sensing resistors, resembling a membrane switch, which change resistance inversely with applied force are one such example of a pressure sensitive switch. Devices of this type offer the substantial advantage of being low cost, flexible, and durable. A variety of other force sensing switch devices may be utilized as well. An alterative safety feature anticipated by the present invention is a monitoring function for detecting dramatic increases in power utilization by the heater trying to maintain an operating temperature. Under normal operation, the heater is in a non-contact position proximate the selected treatment area and the heater will have been programmed to operate at a temperature that may be either a straight temperature value or an averaged value for either a duty cycle, therapy cycle or therapeutic sequence. If physical pressure is placed on the heater and it comes into contact with the patient's body, there will be a considerable increase in the rate of heat loss from the heater because of the body's greater heat sink capacity. The heater controller would sense this drop in temperature and initially adjust either the duty cycle ratio or power output, or both, in an attempt to compensate for the increase rate of loss. The safety aspect of this monitoring function would be to override this increase and turn off the device, thus preventing heating the tissue while in direct contact with, and under pressure from, the heater. Heater element 106 is preferably a thin film type resistance heater which is commercially available. Such thin film resistance heaters utilize low voltage, minimizing the electrical risk to the patient and allowing for battery-powered mobility. Foil heater 106 is preferably sized for each wound covering 108 . In actual use, foil heater 106 is preferably provided in sheets with a pair of electrical leads 110 along one edge. While an electrical resistance heater is the preferred embodiment of the invention, other heating devices are anticipated such as warm water pads, exothermic chemical heating pads, and phase-change salt pads. Heater assembly 100 is preferably insertable into a pocket 114 formed between wound tracing grid 86 and the barrier layer as discussed above. Finally, a temperature monitoring device, such as a liquid crystal temperature monitor, may be applied to an upper surface of heater assembly 100 or within treatment volume 112 to monitor the temperature within treatment volume 112 . FIGS. 4-7 illustrate an alternate embodiment of wound covering 10 . In this embodiment, wound covering 10 includes a generally circular head, designated generally at 12 , which transitions to an elongated non-kinking, collapsible air supply or hose 14 . The apparatus, as illustrated in FIG. 4, is connected by suitable supply line or tube 16 to a source 18 of thermally controlled air which is schematically illustrated. The term air as used herein is intended to encompass mixtures of gases of controlled composition. The apparatus is constructed to apply a continuous stream of thermally controlled air to a wound treatment volume. The specific form of the apparatus and details of construction can best be understood by reference to the various figures. The overall appearance of the wound covering is best seen in FIG. 4 and FIG. 5 . It is preferred to construct the apparatus from top and bottom sheets of thin heat-sealable polymer film which overlay one another. A top sheet or membrane 20 overlies a bottom sheet or membrane 22 which are heat sealed together along a plurality of seal lines, including a continuous outer seam 24 , which extends in a circle around head 12 and continues in a sinusoidal or convoluted fashion along and forming hose 14 . An inner continuous circular seam 26 is provided as best seen in FIGS. 6 and 7. This inner seam 26 secures the sheets together along a continuous circle to form the inner wall of a torus defining a supply volume 28 . The inner circular portion of the two sheets 20 , 22 lying in the plane within the center of the supply volume 28 forms a wall 30 separating a lower wound treatment volume 32 from an upper insulation chamber 34 . Wall 30 includes a plurality of apertures 36 formed by making small circular seals 38 and cutting and removing circular portions within the circular seals 38 . Thus, wall 30 , with a plurality of apertures 36 , is formed between the wound treatment volume 32 and insulation chamber 34 . A plurality of apertures 40 are formed in the common circular wall surrounding treatment volume 32 for distributing and conveying heated air or gases from supply volume 28 into wound treatment volume 32 . The heated air flowing into treatment volume 32 bathes the wound surface of a patient's body 42 . The air circulates throughout wound treatment volume 32 , and then passes through apertures 36 into the upper or insulating chamber 34 , where it the passes through filter 44 forming an outer wall of insulation chamber 34 . Filter 44 filters the air leaving wound treatment volume 32 , trapping contaminants shed from the wound. Filter 44 may be constructed of a filter paper bonded along its periphery to the outer tangential walls of head 12 forming the torus. The filter paper also provides an insulating layer which suppresses loss of heat by radiation through upper wall 30 . The lower surface of the head 12 as shown in FIGS. 6 and 7 is provided with a peripheral sealing ring 46 made of an absorbent material such as foam and bonded by a suitable adhesive to the walls of head 12 and skin 42 of the patient around the wound. Preferably, foam or cotton peripheral seal ring 46 is provided with a peel-off tape so that it adheres to the wall of the housing and on the other side to the skin of the patient. The adhesive or tape holds the apparatus in place and prevents airflow escape between the device and the skin of the patient. The absorbent material of the ring absorbs weeping blood and fluids and insulates the skin from direct conduction of heat from head 12 . Hose 14 is designed to be non-kinking by forming it of symmetrically convoluted flexible material. The hose and housing are integrally formed essentially of a unitary structure, such as a thin film membrane. Hose 14 is inflatable upon the application of heated air through supply line 16 . The indentations in hose 14 permit it to bend without kinking and, thus, differentiate from a straight tubular hose which may kink when bent. Since the thermal body treatment apparatus of the invention and the supply hose section are formed from two, thin, sealed-together membranes, the hose, and in fact the entire apparatus, is collapsible. This prevents the possibility of applying heat and pressure to the skin as might happen if a patient rolled over on the device. Instead, the weight of the patient's body collapses the device, obstructing the flow of air, and preventing the application of heat. The film membrane may preferably be transparent to enable viewing the wound without removal. However for cosmetic reasons the layer may be opaque. Filter paper 44 is attached across the tangential surfaces of the toroidal housing, thus providing a large area of filter for the escaping air. Head 12 of the apparatus may be about one foot in diameter for most applications. However, it may be made smaller for certain other applications. FIG. 8A illustrates an exploded view of an alternate embodiment of a non-contact wound covering 120 with climate control within a treatment volume 122 as shown in FIG. 8 B. An inflatable structure 124 is preferably attached to a fluid inlet line 126 at a fluid inlet port 129 on the perimeter of inflatable structure 124 . Inflatable structure 124 is preferably attached to an absorbent peripheral sealing ring 128 , which is in turn attached to a wound area 54 by a suitable adhesive 56 . Peripheral sealing ring 128 preferably has a sealed outer surface and a porous inner surface which performs the same function as peripheral sealing ring 52 discussed above. A barrier layer 130 having an exhaust filter 132 is attached to a top surface 134 on inflatable structure 124 . Turning now to the assembly illustrated in FIG. 8B, a gas, illustrated by direction arrows “A”, is introduced into inflatable structure 124 from an external source (not shown) through inlet line 126 . The gas pressurizes inflatable structure 124 in order to maintain barrier layer 130 and exhaust filter 132 in an elevated position relative to wound area 54 . An inner surface 136 of inflatable structure 124 preferably has a plurality of apertures 138 through which the fluid is introduced into wound treatment volume 122 . As pressure within the chamber increases, excess pressure is relieved through exhaust filter 132 . In this fashion, various fluids or gases can be introduced into wound treatment volume 122 . The use of the term “fluid” in the context of this application refers to both liquid and gaseous materials, and combinations thereof. In one embodiment, oxygen may be introduced into treatment volume 122 through apertures 138 of inflatable structure 124 . The presence of oxygen within wound treatment volume 122 may increase the oxygen available to the superficial layer of growing cells in wound area 54 . Nitric oxide alternatively may be infused into treatment volume 122 . Nitric oxide (NO) is a potent vasodilator which in theory may be absorbed across the wound surface and increase localized blood flow. A very small concentration of NO (parts per million) may provide this effect. NO may also be pre-absorbed into absorbent peripheral sealing ring 128 and then allowed to passively diffuse into the volume once it is applied to the wound. Finally, gaseous or aerosolized medications or compounds may be introduced into the gas flow entering treatment volume 122 . FIGS. 9A and 9B illustrate an alternate embodiment of the climate control system discussed above wherein a fluid inlet line 140 may form part of a barrier layer 142 . Barrier layer 142 is unitary with fluid inlet line 140 and is preferably attached to an exhaust filter media 144 to allow excess pressure to be released from a wound treatment volume 146 . In this embodiment, filter media 144 forms part of barrier layer 142 . The arrows “A” in FIG. 9B illustrate the movement of the fluid through fluid inlet line 140 , treatment volume 146 , and exhaust filter 144 . FIG. 10 illustrates an alternate embodiment wherein an exhaust filter 154 is retained in a recess 150 formed in one side of a peripheral sealing ring 152 . This structure allows excess fluid to be exhausted through the side of peripheral sealing ring 152 , rather than through the top, as illustrated in FIGS. 9A and 9B. FIG. 11A is a perspective view of the embodiment illustrated in FIG. 9A, wherein a connector 160 on the end of a fluid supply line 162 engages with an opening 164 on fluid inlet line 140 . FIG. 11B illustrates a side view of fluid supply line 162 as it engages with fluid inlet line 140 . FIG. 11C illustrates the embodiment in FIGS. 11A and 11B where fluid inlet line 140 is folded over the top of peripheral sealing ring 152 to seal treatment volume 146 when supply line 162 is uncoupled. FIG. 12 illustrates an alternate embodiment in which a fluid inlet slot 170 engages with a rigid connector 172 on a fluid inlet line 174 . Fluid inlet slot 170 forms an opening in one portion of a peripheral sealing ring 176 . The opening is in fluid communication with a treatment volume 178 . This configuration allows for quick disconnection of fluid inlet line 174 from wound covering 180 providing the patient with additional mobility. FIG. 13A is a perspective view of an alternate non-contact wound covering 190 having a fluid inlet connector 192 attached to a top surface 194 of a peripheral sealing ring 196 . Fluid inlet connector 192 preferably contains an inlet filter media 198 . A rigid connector 200 on a fluid inlet line 202 mates with fluid inlet connector 192 . As illustrated in FIG. 13B, a cover 204 extends from the top of fluid inlet connector 192 across the top of peripheral sealing ring 196 where it engages with an exhaust filter media 206 . FIG. 14 illustrates the embodiment of FIGS. 13A and 13B utilizing a non-disposable fluid supply line 210 . FIG. 15 illustrates an alternate embodiment which utilizes a manifold structure 220 as part of a fluid inlet line 222 to provide even distribution of the fluid being introduced into a treatment volume 224 . Fluid inlet line 222 preferably has a series of seals 226 along its edge which are interrupted by a plurality of side openings 228 from which the fluid can be transmitted into treatment volume 224 . The embodiment disclosed in FIG. 15 illustrates an exhaust filter 230 recessed into the side of peripheral sealing ring 232 . However, it will be understood that a variety of exhaust filter configurations are possible with the disclosed manifold structure 220 . FIGS. 16A and 16B illustrate an alternate wound covering 240 with a top barrier layer 242 and a lower layer 244 having a plurality of holes 246 . As is illustrated in FIG. 16B, a top cover 243 forms the barrier layer 242 and it extends substantially across the area of the peripheral sealing ring 248 . Lower layer 244 likewise extends across the peripheral sealing ring 248 . Thus, an upper insulating layer 250 is formed between lower layer 244 and the top of barrier layer 242 . Fluid in a fluid inlet line 252 is directed into upper insulating layer 250 . The pressurized fluid in upper insulating layer 250 passes through holes 246 into a treatment volume 254 . Holes 246 in lower layer 244 provide a generally even distribution of the fluid within wound treatment volume 254 . An optional seal 258 may be formed in the center portion of barrier layer 242 and lower layer 244 to provide these layers with additional structural support. An exhaust filter medium 256 is provided in a recess along one side of peripheral sealing ring 248 to relieve pressure in treatment volume 254 . FIG. 17 illustrates an alternate embodiment of a non-contact wound covering 260 utilizing semi-rigid supports 262 to retain a barrier layer 264 above a wound area. It will be understood by those skilled in the art that a variety of semi-rigid supports 262 may be utilized for this application. For example, plastic or resilient rubber materials may provide sufficient support to barrier layer 264 with a minimum risk of injuring the patient. FIGS. 18A and 18B illustrate an alternate exhaust filter medium 270 with an enlarged surface area to accommodate larger volumes of air flow through a non-contact wound covering 280 . Exhaust filter 270 is incorporated into a fluid inlet line 272 . Fluid inlet line 272 also forms a portion of a barrier layer 274 , which is in turn attached to a peripheral sealing ring 276 . As is best shown in FIG. 18B, fluid illustrated as the arrows “A” is introduced into a fluid inlet line 272 , where it is directed into a wound treatment volume 278 , past the wound area and out through exhaust filter medium 270 . FIG. 19 illustrates a bi-directional line 290 with a center divider 292 . Fluid is introduced into a fluid inlet line 294 where it proceeds through a fluid inlet port 296 into a treatment volume 298 . The fluid then is forced through a fluid outlet port 300 where it is driven away from treatment volume 298 in a fluid outlet line 302 . It will be understood by those skilled in the art that it would be possible to utilize separate fluid inlet and outlet lines to achieve the same result. A schematic diagram of an embodiment of the present invention using active heating and control is depicted in FIG. 20 as an active heater assembly 310 including a heater 312 , a heater filament 314 within heater 312 , a controller 316 , electrically coupled between heater filament 314 and a power source 318 by electrical connectors 315 , and using a tissue temperature sensor 320 , and an operator input interface 322 suitable for an operator to input programming parameters into controller 316 . Heater assembly 310 is useful in several different configurations, for example, as providing a heater layer for use directly in a pocket such as that depicted by heater 100 inserted into pocket 114 shown in FIGS. 3A and 3B or as a heat source for warming air that is circulated over the wound as is depicted in the several embodiments of FIGS. 4 through 19. In addition to the various suggested fluid delivered heater “geometries” depicted in FIGS. 4-19, the present invention anticipates numerous possible heater electrical resistive filament 314 geometries. Examples of four such geometries are shown in FIGS. 21A, B, C, and D wherein there is depicted additional alternate heater array geometries for heating filament 314 within heater 312 . In FIG. 21A, there is depicted a linear geometry for heater filament 314 . This geometry is suitable for non-uniform heating where maximum heating is desired over a linear area, such as a linear surgical wound without direct heating over adjacent periwound areas. FIG. 21B depicts a geometry for heater filament 314 consistent more as a point source. FIG. 21C depicts an ovoid geometry for filament 314 suitable for non-uniform heating of selected periwound area. Alternatively, this non-uniform heating may be achievable with circular, square, rectangular, triangular or other such geometries depending on the type and shape of wound encountered. In operation, heater assembly 310 is programmable, controlling one or more parameters, such as heater temperature, duty cycle, therapy cycle duration, number of duty cycles per therapy cycle, average heater temperature per duty cycle, and average heater temperature per therapy cycle. The programming may be preset at time of manufacture into controller 316 and provide a menu including treatment scenarios operator selectable at input interface 322 . Additionally, the parameter programmability may be entirely under the control of an operator through input interface 322 and suitable for inputting any number of custom treatment regimens. For example, one regimen anticipates that an operator may input a desired tissue temperature and the target tissue is then monitored through tissue temperature sensor 320 . Alternatively, another regimen anticipates that an operator may input a treatment paradigm using parameters based on empirical modeling of tissue temperature responses for the various types of wounds, wound size, wound stage and wound location. Desired tissues targeted for monitoring may be the wound surface, the tissue below the wound surface, the periwound surface and tissue below the periwound surface. Empirical modeling may be based on parameters such as thermodynamic characteristics of tissue temperature conduction rates, surface area to be treated, tissue volume to be treated, wound type, wound location, wound staging, and heater geometries and heater outputs as a few of the paradigm values. Such programmable treatment paradigms are tissue temperature sensor independent and therefor tissue temperature sensor 320 is not needed in this mode. By way of example, and not liming in scope of treatment versatility, FIG. 22 is a graphic representation of one such regimen. In FIG. 22, several heater duty cycles have been depicted as a curve 330 and the tissue temperature response as a curve 332 . Tune (t) is represented along the abscissa and temperature (T) along the ordinate. A tissue temperature target value T tar 334 has been entered either by program or direct input from the operator and the heater started at t 0 334 . The tissue start temperature is at a temperature T a 336 and the starting heater temperature is at ambient temperature T amb 338 . By turning on the heater at t 0 334 , the first of several duty cycles for the heater begins in order to provide heat with which to raise the tissue temperature to T tar 334 . A heater operating temperature T h 340 is chosen by the controller based on the value, either programmed or inputted, for T tar 334 and the heater controller provides the appropriate duty cycle ratio and heater cycle period so as to provide a safe and efficacious heating of at least a portion of the selected wound treatment area. The tissue target temperature T tar 334 value is reached at t 1 342 , at which time the heater is turned off. Alternatively, although not shown, upon reaching T tar 334 , the controller could have changed T h 340 to a lower value and kept the heater active in order to maintain the tissue temperature at T tar 334 . By way of another example, and not limiting in scope of treatment versatility, a plurality of therapy cycles are depicted in FIG. 23, wherein individual heater cycles within each therapy cycle have been averaged out for purposes of clarification and for purposes herein are treated as the heater being “on”. A first therapy cycle begins at t 0 350 as depicted by the heater turning “on”, i.e., a series of heater cycles is begun as shown by a heater temperature curve 352 . A tissue temperature target value T tar 354 has been entered either by program or direct from the operator and the tissue temperature response is shown in a curve 356 . The tissue start temperature is at a temperature T a 358 and the starting heater temperature is at about ambient temperature T amb 360 . The heater remains “on” until the tissue temperature has reached T tar 354 as monitored directly or as predicted by an appropriate heating paradigm. As shown T tar 354 is reached at t 1 362 at which time the heater is turned “off”. As in the previous example, an alternative is that the heater controller selects an alternate heating output, chosen to maintain the tissue temperature at about T tar 354 . As depicted in FIG. 23, however, the tissue temperature is allowed to drift downwardly with the heater “off” until the tissue temperature reaches a temperature T min 364 that is either programmed or pre-selected as a value in the selected paradigm. Upon reaching T min 364 , the heater is turned “on” again, as shown at t 2 366 , so as to provide heat to the selected treatment area to raise the tissue temperature to T tar 354 . This first therapy cycle ends at t 2 366 when a second therapy cycle begins by turning “on” the heater again. As in the first therapy cycle, this second therapy cycle provides heat to the tissue to reach the tissue target temperature, T tar 354 . Alternatively this second therapy cycle may have a different T tar 354 , or optionally may have a different cycle length calling for the controller to change the heater output. The present invention anticipates the use of any number of therapy cycles having any length or duration per cycle and different set temperatures, and a plurality of therapy cycles contributing to a therapeutic sequence. For the above examples, T tar 354 may be programmed as a paradigm or directly inputted into the controller. For the present invention, this tissue target temperature is in a range preferably from a pretreatment temperature to about 38° C. Another aspect of therapy control according to the present invention is the averaging of therapy cycle and therapeutic sequence tissue target temperatures, as depicted in FIG. 24 . The example is not intended to be limiting in scope of treatment versatility. In FIG. 24, a therapy cycle starts at t 0 370 and ends at t 1 372 . The tissue target temperature average T ave 374 for this therapy cycle may be pre-selected or programmed. The tissue temperature change, as depicted by a temperature curve 376 , begins at a temperature T a 376 , rises as it is heated by the heater to T b 378 during the “on” phase of the heater, as depicted by a heater temperature curve 380 , and then drifts downwardly to T c 382 over an additional period of time such that the total period of time is equivalent to the period t 0 370 to t 1 372 . T ave 374 represents the average of the temperatures between T a 376 and T b 378 , or in the alternative the average between T a 376 and T c 382 over the time period t 0 370 to t 1 372 . An alternative approach, also depicted in FIG. 24, anticipates the programming of a number of therapy cycles as elements of a therapeutic sequence, in this example there being two therapy cycles of varying times and tissue target temperatures. The present invention provides for the inputting of an average tissue target temperature T ave 384 for the therapeutic sequence, in this example, extending from t 0 370 to t 0 386 . Each of these average temperatures, whether an average over a therapy cycle or over a therapeutic sequence, is intended to have the same temperature range from a pretreatment temperature to about 38° C. A secondary consequence of this controller regimen is that if average temperatures are used, either over the therapy cycle and/or therapeutic sequence, then the resultant peak tissue temperature may be higher than this range. These peak temperatures are short lived by comparison and do not represent a safety concern. The present invention is the development of a safe, efficacious non-contact heater wound covering providing heat to a patient's wound from the heater that warms a target tissue controlled to a temperature in a range from a pretreatment temperature to about 38° C., or controlled to an average temperature in a range from a pretreatment temperature to about 38° C. While the invention has been illustrated by means of specific embodiments and examples of use, it will be evident to those skilled in the art that many variations and modifications may be made therein without deviating from the scope and spirit of the invention. However, it is to be understood that the scope of the present invention is to be limited only by the appended claims. TABLE 1 Time Subcutaneous Temperature (in minutes) (° C. mean ± S.D.) −60 33.9 ± 1.1 0 34.7 ± 1.2 30 36.9 ± 0.6 60 37.1 ± 0.4 90 37.4 ± 0.5 120 37.6 ± 0.5 180 36.0 ± 0.4 240 36.1 ± 0.2 300 35.8 ± 0.6 TABLE 2 Time Skin Temperature Inside Covering (in minutes) (° C. mean ± S.D.) −60 33.2 ± 1.1 0 33.9 ± 1.1 30 36.7 ± 0.5 60 37.0 ± 0.4 90 37.1 ± 0.4 120 37.2 ± 0.4 180 35.2 ± 0.5 240 35.2 ± 0.4 300 35.1 ± 0.5 TABLE 3 Time Laser Doppler Flow (in minutes) (ml/100 g/min mean ± S.D.) −60 64 ± 42 0 110 ± 100 30 199 ± 191 60 178 ± 131 90 222 ± 143 120 271 ± 235 180 158 ± 146 240 146 ± 125 300 173 ± 158 TABLE 4 Time Subcutaneous Oxygen Tension (P sq O 2) (in minutes) (mm Hg mean ± S.D.) −60  54 ± 10 0 110 ± 60 30 109 ± 58 60 122 ± 59 90 136 ± 57 120 159 ± 55 180 153 ± 60 240 156 ± 61 300 148 ± 52 TABLE 5 Time Subcutaneous Temperature (in minutes) (° C.) −60 33.8 ± 1.5 0 35.2 ± 1.5 30 37.1 ± 1.1 60 37.3 ± 0.8 90 37.4 ± 0.7 120 37.3 ± 0.8 180 35.8 ± 1.2 240 35.8 ± 1.0 300 36.1 ± 0.9 TABLE 6 Time Skin Temperature Inside Covering (in minutes) (° C.) −60 32.9 ± 1.5 0 34.5 ± 1.0 30 37.1 ± 0.6 60 37.5 ± 0.5 90 37.6 ± 0.5 120 37.6 ± 0.5 180 34.9 ± 0.8 240 35.0 ± 0.7 300 35.2 ± 0.6 TABLE 7 Time Laser Doppler Flow (in minutes) (ml/100 g/min) −60 44 ± 22 0  95 ± 132 30 142 ± 155 60 191 ± 150 90 207 ± 209 120 161 ± 91  180 73 ± 29 240 70 ± 30 300 71.5 ± 25   TABLE 8 Time Subcutaneous Oxygen Tension (P sq O 2 ) (in minutes) (mm Hg) −60  58 ± 11 0 123 ± 73 30 128 ± 67 60 145 ± 69 90 157 ± 73 120 153 ± 55 180 148 ± 73 240 142 ± 73 300 143 ± 76

A covering to treat tissue by raising the temperature of the tissue toward a normothermic level includes a flexible material with upper and lower surfaces and an opening to face a tissue treatment area, an attachment portion near the lower surface, and a heater layer supported by the upper surface, over the opening, to maintain tissue at a temperature in a range from a pretreatment temperature to about 38° C.

CROSS-REFERENCE TO RELATED APPLICATION This application is a National Phase Application of PCT International Application No. PCT/CN2012/073588, International Filing Date Apr. 6, 2012, claiming priority of Chinese Patent Applications, 201110086701.8, filed Apr. 7, 2011, all of which are incorporated herein by reference in their entirety. TECHNICAL FIELD The invention relates to the medicinal chemistry field. In particular, the invention relates to a benzopyrone derivative and the use thereof for the treatment of psychoneurosis. BACKGROUND Schizophrenia is a type of disease characterized in severely schizophrenic cognition and emotion, presenting as the influence on the basic behavior of a human, such as language, thinking, feeling, self-perception or the like. This disease encompasses a large variety of disorders, such as those involved in psyche, e.g. delusion, paranoia, illusion or the like. Schizophrenia is the most serious mental disease. About 1% of the people all over the world suffer from schizophrenia, and only 5% of them can be cured after treatments. In addition, schizophrenia is always accompanied with various complications, e.g. anxiety, depression, psychic drug abuse or the like. It was shown in a study by Datamonitor that over ⅓ of the patients with schizophrenia suffer from one or more complicated psychoses or cognitive disorders. The anti-psychosis drug exerting its pharmacological action by blocking dopamine D 2 receptor is conventionally known as the 1 st generation anti-psychosis drug, i.e. the “typical” anti-psychosis drug (e.g. haloperidol). This drug is effective for schizophrenia positive symptoms, but not effective for negative symptoms and cognitive disorders. Furthermore, the typical anti-psychosis drug generally has serious EPS side effects and is not effective for ⅓ of the patients with schizophrenia. A series of new anti-psychosis drugs have been developed since 1960s, including ziprasidone, risperidone or the like, which are considered as the 2 nd generation anti-psychosis drug (the novel anti-psychosis drug). Although these drugs have different pharmacological actions, they share the same pharmacological properties, i.e. the affinities for 5-HT 2A receptor and noradrenalin (NA) receptor (α1, α2) are much higher than those for D 2 receptor, resulting the decrease of the ratio D 2 /5-HT 2A . Their clinical effects are more advantageous over those of the 1 st generation anti-psychosis drugs, since they are effective for the positive symptoms like the conventional anti-psychosis drug, and are effective for the negative symptoms and cognitive defect symptoms and have broader application spectrum. However, these drugs have the side effects of extended QT interval, hyperprolactinemia, weight gain or the like. Therefore, it is needed to find a new drug, which is effective for schizophrenia positive and negative symptoms and cognitive disorders, and has fewer side effect. Aripiprazole belongs to a butyl benzene prazosin compound, which was approved by FDA in November, 2002. This drug has a particular action mechanism as having high affinities with dopamine D 2 , D 3 , 5-HT 1A and 5-HT 2A receptors, and medium affinities with D 4 , 5-HT 2C , 5-HT 7 , α1, H1 receptors and 5-HT essential absorbing site. Aripiprazole exerts its effect against schizophrenia through its partial agonistic action for D 2 and 5-HT 1A receptors and antagonistic action for 5-HT 2A receptor, and has the effect of stabilizing dopamine systemic activity. Clinical trials have shown that aripiprazole is effective for both the positive and negative symptoms of schizophrenia, and its long-term application can reduce the reoccurrence of schizophrenia, and improve emotion and cognitive function disorders. Moreover, its EPS side effects and the effect of increasing serum prolactin level are less than those of the conventional anti-psychosis drug or the above non-typical anti-psychosis drug. 5-hydroxy tryptamine system plays an important role in modulating the function of prefrontal cortex (PFC), including emotion control, cognitive behavior and working memory. The pyramidal neurons and GABA interneurons of PFC contain several 5-hydroxy tryptamine receptor subtypes 5-HT 1A and 5-HT 2A in high density. It has been shown recently that PFC and NMDA receptor channels are the targets of 5-HT 1A receptor, and these two receptors modulate the excitatory neuron of cerebral cortex, thereby affecting the cognitive function. In fact, various preclinical data have shown that 5-HT 1A receptor may be the new target of the development of anti-psychosis drug. The high affinity of non-typical anti-psychosis drug (e.g. olanzapine, aripiprazole or the like) to 5-HT 1A receptor and its low EPS side effects indicate that 5-hydroxy tryptamine system plays an important role in modulating the function of prefrontal cortex (PFC), including emotion control, cognitive behavior and working memory. It has been shown recently that 5-HT 1A agonist is associated with non-typical anti-psychosis drug therapy, which can improve negative symptoms and cognitive disorders. In the treatment of schizophrenia with the non-typical anti-psychosis drug clozapine, it was found that 5-HT 2A plays an important role in various aspects, including cognition, emotion regulation and motion control. The blocking of 5-HT 2A receptor can normalize the release of dopamine, exerting the effect of anti-psychosis. In addition, 5-HT 2C receptor is closely related with weight gain. The distribution of D 3 receptor in brain mainly locates specifically at limbic system and there are two major DA neural pathways in brain: one is nigrostriatal pathway regulating the motion function, while the other is mesencephalic ventral tegmental area-accumbens nucleus-prefrontal cortex. DA pathway is closely associated with learning cognition and emotion behavior, of which the disorder will lead to schizophrenia. This DA pathway is the main pathway of reward effect in brain. D 3 receptor is distributed in both of the DA neural pathways, and has complex interaction with other DA receptor subtypes, and thus may be the target of anti-psychosis drug therapy. Selective D 3 receptor antagonism can reduce the negative and cognitive symptoms of schizophrenia, which can additionally prevent extrapyramidal system side effects, including tardive dyskinesia, Parkinson's disease or the like. Therefore, it is needed to find novel anti-schizophrenia drug which can bind to multiple receptors and has less side effects clinically. SUMMARY It is the object of the invention to provide a novel benzopyrone derivative with activity based on the prior art. It is another object of the invention to provide a method for treating neuropsychical disease, comprising administrating the benzopyrone derivative according to the invention to the patient in need thereof. It is another object of the invention to provide the use of the above-mentioned benzopyrone derivative in the manufacture of a medicament for the treatment or prevention of neuropsychical disease. The objects of the invention can be achieved by the following solutions. A benzopyrone derivative having the structure of formula (I) or a pharmaceutically acceptable salt thereof, wherein, Z is —(CH 2 ) n , which is unsubstituted or substituted by one or more substituents independently selected from the group consisting of hydroxyl and C 1-5 alkyl, wherein n is an integer of 2-6, and the carbon chain of Z optionally has a double bond(s) Y is O or S; Q is N or CH; X is O, S or NH; the dashed line represents a single bond or a double bond; R 1 , R 3 , R 4 and R 5 are each independently H; halogen; cyano; hydroxyl; C 5-14 aryl, which is unsubstituted or substituted by one or more substituents independently selected from the group consisting of halogen, amino and hydroxyl; C 1-5 alkyl, which is unsubstituted or substituted by one or more substituents independently selected from the group consisting of halogen, amino and hydroxyl; or C 1-5 alkoxy, which is unsubstituted or substituted by one or more substituents independently selected from the group consisting of halogen, amino and hydroxyl; wherein the halogen is preferably Cl or F; R 2 is H; or C 1-5 alkyl, which is unsubstituted or substituted by one or more substituents independently selected from the group consisting of halogen, amino and hydroxyl. Preferably, in formula (I), Z is —(CH 2 ) n , which is unsubstituted or substituted by one or more hydroxyl, n is an integer of 2-5, and the carbon chain of Z optionally has a double bond(s); and most preferably, n is 3, 4 or 5. Preferably, in formula (I), Y is O; X is O or S. Preferably, in formula (I), R 1 is H, phenyl, halophenyl, C 1-5 alkyl, C 1-5 haloalkyl or C 1-5 hydroxylalkyl, wherein the halogen (halo) is preferably Cl or F. Most preferably, R 1 is H, phenyl, methyl, ethyl, propyl, trifluoromethyl or hydroxymethyl. Preferably, in formula (I), R 3 , R 4 and R 5 are each independently H, halogen or C 1-5 alkyl, wherein the halogen is preferably Cl or F. Most preferably, R 3 is H, Cl or methyl; R 4 is H, Cl or methyl; R 5 is H, F or methyl. Preferably, in formula (I), R 2 is H or methyl. In formula (I), when Q is CH, X is O, R 5 is F; or when Q is N, X is S, R 5 is H. The above benzopyrone derivatives are selected from the following compounds or the pharmaceutically acceptable salts thereof: 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-2H-benzopyran-2-one; 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-2H-benzopyran-2-one; 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-methyl-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-methyl-2H-benzopyran-2-one; 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-methyl-2H-benzopyran-2-one; 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-methyl-2H-benzopyran-2-one; 7-(5-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-pentyloxy))-4-methyl-2H-benzopyran-2-one; (E)-7-(4-(4-(3-(6-fluoro-benzisoxazole)-3-piperidyl)-but-2-enyloxy))-4-methyl-2H-benzopyran-2-one; 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-phenyl-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-phenyl-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-phenyl-2H-benzopyran-2-one; 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one; 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-methyl-8-chloro-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-methyl-8-chloro-2H-benzopyran-2-one; 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-methyl-8-chloro-2H-benzopyran-2-one; 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-methyl-8-chloro-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4,8-dimethyl-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-8-dimethyl-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-n-propyl-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-n-propyl-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-ethyl-2H-benzopyran-2-one; 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-ethyl-2H-benzopyran-2-one; 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-3,4-dimethyl-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-3,4-dimethyl-2H-benzopyran-2-one 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-hydroxymethyl-2H-benzopyran-2-one; 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-hydroxymethyl-2H-benzopyran-2-one; 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-2-hydroxylpropoxy))-4-methyl-2H-benzopyran-2-one; 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-2-hydroxylpropoxy))-4-phenyl-2H-benzopyran-2-one; and 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-phenyl-benzopyran-2-one. DETAILED DESCRIPTION OF THE INVENTION For the purpose of the invention, the term “C 1-5 alkyl” refers to a linear or branched alkyl containing 1, 2, 3, 4, or 5 carbon atoms. For example, C 1-5 alkyl may be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, neopentyl or the like. The term “C 1-5 alkoxy” refers to the above defined C 1-5 alkyl, which is attached to the rest of the molecule via an oxygen atom. The term “aromatic ring” refers to an aromatic ring group having 5-14 carbon ring atoms, preferably 5-10 or 6-10 carbon ring atoms, for example, phenyl or naphthyl. Any aryl defined herein may be substituted by one, two or more substituents preferable selected from the group consisting of halogen, hydroxyl, cyano, amino, C 1-5 alkyl (e.g. methyl or ethyl), and C 1 -C 5 alkoxy (e.g methoxy). The term “halogen” refers to F (fluorine), Cl (chlorine), Br (bromine) or I (iodine). The compound of formula (I) can be reacted with a pharmaceutically acceptable acid to form a pharmaceutically acceptable salt, which may be hydrochloride, hydrobromide, hydriodate, nitrate, sulfate or bisulfate, phosphate or acid phosphate, acetate, lactate, citrate, tartrate, maleate, fumarate, mesylate, gluconate, saccharate, benzoate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate or the like. The general synthesis procedures of the present compounds can be performed by synthesizing the parent structure of benzopyrone, and then the attaching it to 1,2-benzisoxazole or 1,2-benzisothiazole substituted by a piperazinyl or a piperidyl via a carbon chain. For example, the compounds of the invention can be synthesized according to following Schemes 1-5. The invention provides a pharmaceutical composition, comprising the compound of formula (I) or the pharmaceutically acceptable salt thereof, and pharmaceutically acceptable adjuvant (e.g. carrier and/or excipient). This pharmaceutical composition is an anti-psychosis composition comprising the compound according to the invention in an amount sufficient to exert anti-psychosis effect. The effective dose of the present compounds can be orally administrated with, for example, inert diluent or some carriers. It can be encapsulated in a gelatin capsule or compressed into a tablet. For the purpose of oral administration, the compounds according to the invention can be used with excipients and in the forms of tablet, troche, capsule, suspension, syrup or the like. These formulation should contain the active compounds according to the invention in an amount of at least 0.5 wt %, but such an amount can vary according to particular formulations, and the amount of 4-7% by weight will be beneficial. The active compounds should be present in a suitable dosage in such compositions. The oral unit dose of the preferable composition and formulation contains 1.0-300 mg of the active compounds according to the invention. The compound provided herein, i.e. the compound of formula (I) and the pharmaceutically acceptable salt, solvate and hydrate thereof can be combined with the pharmaceutically acceptable carrier or diluent to form a pharmaceutical formulation. The pharmaceutically acceptable carrier comprises inert solid filler or diluent and sterile aqueous solution or organic solution. The dosage of the compound according to the invention depends on the type and severity of the disease or disorder, and the nature of the subject, for example, general health, age, gender, weight and drug tolerance. A person skilled in the art can determine the suitable dosage according to these or other factors. The effective dosage for a central nervous system drug is well known to a person skilled in the art. The total daily dosage is generally about 0.05 mg-2000 mg. The invention relates to a pharmaceutical composition, which can provide about 0.01-1000 mg active ingredient per unit dose. The composition can be administrated in any suitable route, for example, oral administration in a capsule, parenteral administration in an injection, topical administration in an ointment or a lotion, rectal administration in a suppository, or transdermal administration in a patch. The compounds according to the invention can be combined with suitable solid or liquid carrier or diluent to form capsule, tablet, pill, powder, syrup, solution or the like. The tablet, pill, capsule or the like contains about 0.01% to about 99% by weight of active ingredients and binder, such as gelatin, maize starch, arabic gum etc; excipient, such as calcium hydrophosphate; disintegrant, such as maize starch, potato starch or alginic acid; lubricant, such as magnesium stearate; and sweetener, such as sucrose, lactose. When the formulation is in the form of capsule, in addition to above materials, it may contain liquid carrier, for example, grease. For the parenteral administration, the compounds according to the invention can be combined with sterile water or organic medium to form injectable solution or suspension. The compounds according to the invention may contain a chiral center(s), thereby being present in the form of different enantiomers or diastereomers. Accordingly, the invention relates to all the optical isomers and all the stereoisomers of the present compounds, in the forms of racemic mixture and respective enantiomers and diastereomers. Moreover, the invention relates to the above defined compounds or all the pharmaceutical compositions containing or using the same as well as the therapeutical method using the same. Furthermore, the compounds according to the invention and the pharmaceutical composition containing the same may be used to prepare a medicament for the treatment or prevention of a neuropsychical disease selected from the group consisting of mental disorder, anxiety, personality disorder, depression, mania, migraine, epilepsy or spasticity disorder, childhood disorder, Parkinson's disease, cognitive disorder, neural degeneration, neurotoxicity and ischemia, preferably schizophrenia. The compounds according to the invention may also be used to prepare a medicament for the treatment or prevention of other central nervous system diseases, for example, depression, memory disorder and functional disorders associated with intelligence, learning or the like. It is shown in the in vitro receptor binding assay that the derivates according to the invention have relatively high affinities for dopamine D 2 , D 3 , 5-HT 1A and 5-HT 2A receptors, while low affinities for 5-HT 2C . It is shown in the animal experiments that these compounds can significantly improve the MK-801 induced high activity and effectively improve the apomorphine induced clambering symptoms, without causing EPS at effective dosage. Since these in vitro acting targets and in vivo pharmacological models are closely associated with dopamine function disorder induced neural system disease, particularly schizophrenia, the compounds according to the invention have the therapeutic effect for neuropsychical disease, especially schizophrenia. EXAMPLES The following Examples are provided for illustrative purposes rather than limiting to the invention. A. Synthetic Examples Example 1 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-2H-benzopyran-2-one (1) The target compound was synthesized according to Scheme 1. 1) 5.5 g of resorcinol and 6.7 g of d,l-malic acid were added to 50 ml of 70% HClO 4 , and the solution was heated to 90° C. for reaction. The solution became clear slowly, and the reaction was completed after 4 hours. The reaction mixture was cooled to room temperature, and the reaction liquid was poured into an ice-water mixture. A large amount of solid was precipitated, which were filtrated. The cake was washed with water. Recrystallization with 95% ethanol gave 4.5 g of white crystal. Melting point: 226-228° C., Yield: 60.8%. 2) 5 g of product of step 1), 6 g of anhydrous potassium carbonate, 50 ml of acetone and 8.2 g of 1,4-dibromobutane were heated under reflux for 6 hours. Then the mixture was cooled to room temperature and filtrated. The solvent was distilled to give yellowish oil, which was passed through a column to give 5.4 g of white solid. Melting point: 55-57° C., Yield: 60.7%. 3) 0.52 g of the product of step 2), 0.65 g of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride, 2 g of anhydrous potassium carbonate, 0.2 g of potassium iodide and 25 ml of acetonitrile were heated under reflux for 12 hours. Then the mixture was cooled to room temperature, and the solvent was distilled. A suitable amount of dichloromethane was added to the mixture, which was then washed with water. The aqueous layer was discarded, and to the organic layer was added anhydrous magnesium sulfate for drying. The solvent was distilled to give yellowish oil. Column chromatography gave 0.55 g of white solid. Melting point: 116-118° C., Yield: 72.3%. 1 H NMR (CDCl 3 ) δ 1.73-1.88 (m, 4H), 2.06-2.16 (m, 6H), 2.48 (t, 2H, J=14.4 Hz), 3.07-3.10 (m, 4H), 4.07 (t, 2H, J=12 Hz), 6.24 (d, 1H, J=9.6 Hz), 6.80-6.86 (m, 2H), 7.05 (t, 1H, J=1.6 Hz), 7.22-7.24 (m, 1H), 7.37 (d, 1H, J=8.4 Hz), 7.63-7.69 (m, 2H) MS (ESI) m/z 437.2 ([M+H] + ) Example 2 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-2H-benzopyran-2-one (2) The target compound was prepared according to the procedures of Example 1, using 3-(1-piperazinyl)-1,2-benzisothiazole hydrochloride instead of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride. Melting point 103-105° C. 1 H NMR (CDCl 3 ) δ 1.75-1.76 (m, 2H), 1.87-1.91 (m, 2H), 2.51 (t, 2H, J=14.8 Hz), 2.68-2.71 (m, 4H), 3.56-3.59 (m, 4H), 4.06 (t, 2H, J=12.4 Hz), 6.23 (d, 1H, J=9.6 Hz), 6.80-6.85 (m, 2H), 7.33-7.37 (m, 2H), 7.44-7.48 (m, 1H), 7.62 (d, 1H, J=9.6 Hz), 7.80 (d, 1H, J=8 Hz), 7.91 (d, 1H, J=8 Hz) MS (ESI) m/z 436.2 ([M+H] + ) Example 3 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-2H-benzopyran-2-one (3) The target compound was prepared according to the procedures of Example 1, using 1,3-dibromopropane instead of 1,4-dibromobutane. Melting point: 128-130° C. 1 H NMR (CDCl 3 ) δ 2.03-2.19 (m, 8H), 2.60 (t, 2H, J=14.4 Hz), 3.07-3.10 (m, 3H), 4.12 (t, 2H, J=12.8 Hz), 6.25 (d, 1H, J=9.2 Hz), 6.84-6.87 (m, 2H), 7.05-7.06 (m, 1H), 7.23-7.27 (m, 1H), 7.37 (d, 1H, J=8.4 Hz), 7.63-7.70 (m, 2H) MS (ESI) m/z 423.2 ([M+H] + ) Example 4 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-2H-benzopyran-2-one (4) The target compound was prepared according to the procedures of Example 1, using 1,3-dibromopropane instead of 1,4-dibromobutane. Melting point: 91-93° C. 1 H NMR (CDCl 3 ) δ 2.04-2.08 (m, 2H), 2.64 (t, 2H, J=14.4 Hz), 2.70-2.73 (m, 4H), 3.57-3.59 (m, 4H), 4.12 (t, 2H, J=12.8 Hz), 6.23 (d, 1H, J=9.6 Hz), 6.82-6.86 (m, 2H), 7.33-7.37 (m, 2H), 7.44-7.48 (m, 1H), 7.62 (d, 1H, J=9.6 Hz), 7.80 (d, 1H, J=8 Hz), 7.91 (d, 1H, J=8 Hz) MS (ESI) m/z 422.2 ([M+H] + ) Example 5 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-methyl-2H-benzopyran-2-one (5) The target compound was synthesized according to Scheme 2. 1) 30 ml of concentrated sulfuric acid was stirred in an ice bath, to which was added resorcinol (5.5 g), and ethyl acetoacetate (9.2 g) dropwise. The solution turned yellow from yellowish, and the reaction was completed after 18 hours. The reaction liquid was poured into ice/water mixture, and white solid was precipitated, which was filtrated. The cake was washed with water to neutral. Recrystallization with 75% ethanol gave 8.5 g of white crystal. Melting point: 186-188° C., yield: 73.9%. 2) 5 g of the product of step 1), 6 g of anhydrous potassium carbonate, 50 ml of acetone and 8.7 g of 1,4-dibromobutane were heated under reflux for 4 hours, and then cooled to room temperature. The mixture was filtrated and the solvent was distilled to give yellowish oil, which was passed through a column to give 6.5 g of white solid. Melting point: 58-60° C., yield: 77.8%. 3) To 0.5 g of the product of step 2) were added 0.6 g of 3-(1-piperazinyl)-1,2-benzisothiazole hydrochloride, 2 g of anhydrous potassium carbonate, 0.2 g of potassium iodide and 25 ml of acetonitrile, and the mixture was heated under reflux for 20 hours, and then cooled to room temperature and filtrated. The solvent was distilled to give yellowish oil, which was passed through a column to give 0.52 g of white solid. Melting point: 110-112° C., yield: 72.2%. 1 H NMR (CDCl 3 ) δ 1.75-1.90 (m, 4H), 2.38 (s, 3H), 2.51 (t, 2H, J=14.4 Hz), 2.68-2.71 (m, 4H), 3.56-3.58 (m, 4H), 4.06 (t, 2H, J=12 Hz), 6.11 (s, 1H), 6.80-6.86 (m, 2H), 7.29-7.36 (m, 1H), 7.43-7.48 (m, 2H), 7.79 (d, 1H, J=8 Hz), 7.90 (d, 1H, J=8.4 Hz) MS (ESI) m/z 450.2 ([M+H] + ) Example 6 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-methyl-2H-benzopyran-2-one (6) The target compound was prepared according to the procedures of Example 5, using 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride instead of 3-(1-piperazinyl)-1,2-benzisothiazole hydrochloride. Melting point: 126-128° C. 1 H NMR (CDCl 3 ) δ 1.71-1.92 (m, 4H), 2.09-2.19 (m, 6H), 2.09 (s, 3H), 2.50 (t, 2H, J=14.4 Hz), 3.09-3.12 (m, 3H), 4.07 (t, 2H, J=12.8 Hz), 6.13 (s, 1H), 6.81-6.88 (m, 2H), 7.03-7.08 (m, 1H), 7.23-7.25 (m, 1H), 7.49 (d, 1H, J=8.8 Hz), 7.69-7.72 (m, 1H) MS (ESI) m/z 451.3 ([M+H] + ) Example 7 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-methyl-2H-benzopyran-2-one (7) The target compound was prepared according to the procedures of Example 6, using 1,3-dibromopropane instead of 1,4-dibromobutane. Melting point: 138-140° C. 1 H NMR (CDCl 3 ) δ 2.02-2.23 (m, 8H), 2.40 (s, 3H), 2.60 (t, 2H, J=14.4 Hz), 3.07-3.10 (m, 3H), 4.12 (t, 2H, J=12.8 Hz), 6.13 (s, 1H), 6.84-6.89 (m, 2H), 7.06 (t, 1H, J=2 Hz), 7.23-7.27 (m, 1H), 7.50 (d, 1H, J=8.8 Hz), 7.71 (t, 1H, J=8.8 Hz) MS (ESI) m/z 437.2 ([M+H] + ) Example 8 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-methyl-2H-benzopyran-2-one (8) The target compound was prepared according to the procedures of Example 5, using 1,3-dibromopropane instead of 1,4-dibromobutane. Melting point: 113-115° C. 1 H NMR (CDCl 3 ) δ 2.06-2.08 (m, 2H), 2.38 (s, 3H), 2.64 (t, 2H, J=14.4 Hz), 2.70-2.73 (m, 4H), 3.57-3.59 (m, 4H), 4.12 (t, 2H, J=12.4 Hz), 6.12 (s, 1H), 6.82-6.88 (m, 2H), 7.35-7.49 (m, 3H), 7.80 (d, 1H, J=8 Hz), 7.91 (d, 1H, J=8.4 Hz) MS (ESI) m/z 436.2 ([M+H] + ) Example 9 7-(5-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-pentyloxy))-4-methyl-2H-benzopyran-2-one (9) The target compound was prepared according to the procedures of Example 6, using 1,5-dibromopentane instead of 1,4-dibromobutane. Melting point: 119-121° C. 1 H NMR (CDCl 3 ) δ 1.53-1.63 (m, 4H), 1.85-1.89 (m, 2H), 2.05-2.14 (m, 6H), 2.40 (s, 3H), 2.43 (t, 2H, J=14.8 Hz), 3.06-3.08 (m, 3H), 4.04 (t, 2H, J=12.8 Hz), 6.12 (s, 1H), 6.80-6.87 (m, 2H), 7.02-7.07 (m, 1H), 7.22-7.24 (m, 1H), 7.49 (d, 1H, J=4.8 Hz), 7.67-7.71 (m, 1H) MS (ESI) m/z 465.3 ([M+H] + ) Example 10 (E)-7-(4-(4-(3-(6-fluoro-benzisoxazole)-3-piperidyl)-but-2-enyloxy))-4-methyl-2H-benzopyran-2-one (10) The target compound was prepared according to the procedures of Example 6, using 1,4-dibromo-2-butene instead of 1,4-dibromobutane. Melting point: 129-130° C. 1 H NMR (CDCl 3 ) δ 2.05-2.17 (m, 6H), 2.39 (s, 3H), 3.05-3.13 (m, 5H), 4.06 (t, 2H, J=12.8 Hz), 5.91-5.96 (m, 2H), 6.13 (s, 1H), 6.83-6.90 (m, 1H), 7.05-7.06 (m, 1H), 7.22-7.27 (m, 1H), 7.49 (d, 1H, J=8.8 Hz), 7.68-7.70 (m, 1H) MS (ESI) m/z 449.2 ([M+H] + ) Example 11 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-phenyl-2H-benzopyran-2-one (11) 1) To 5.5 g of resorcinol and 9.6 g of ethyl benzoylacetate was added 30 ml of phosphoric acid, and the mixture was stirred under room temperature. The solution turned yellow from yellowish, and the reaction was completed after 12 hours. The reaction liquid was poured into ice/water mixture, and a lot of solid was precipitated, which was filtrated. The cake was washed with water. Recrystallization with 95% ethanol gave 9.3 g of white crystal. Melting point: 237-239° C., yield: 80.9%. 2) 4.8 g of the product of step 1), 6 g of anhydrous potassium carbonate, 50 ml of acetone and 8.4 g of 1,3-dibromopropane were heated under reflux for 4 hours, and then cooled to room temperature and filtrated. The solvent was removed by rotation and the residue was passed through a column to give 5.6 g of white solid. Melting point: 67-69° C., yield: 78.0%. 3) To 0.5 g of the product of step 2) were added 0.6 g of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride, 2 g of anhydrous potassium carbonate, 0.2 g of potassium iodide and 25 ml acetonitrile, and the mixture was heated under reflux for 24 hours and then cooled to room temperature and filtrated. The solvent was distilled to give yellowish oil, which was passed through a column to give 0.51 g of white solid. Melting point: 185-187° C., yield: 73.9%. 1 H NMR (CDCl 3 ) δ 2.04-2.19 (m, 8H), 2.67-2.77 (m, 6H), 3.07-3.10 (m, 3H), 4.13 (t, 2H, J=12.4 Hz), 6.22 (s, 1H), 6.79-6.82 (m, 1H), 6.91-6.92 (m, 1H), 7.05-7.06 (m, 1H), 7.23-7.27 (m, 1H), 7.37-7.51 (m, 6H), 7.68-7.71 (m, 1H) MS (ESI) m/z 499.3 ([M+H] + ) Example 12 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-phenyl-2H-benzopyran-2-one (12) The target compound was prepared according to the procedures of Example 11, using 3-(1-piperazinyl)-1,2-benzisothiazole hydrochloride instead of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride. Melting point: 96-98° C. 1 H NMR (CDCl 3 ) δ 2.05-2.08 (m, 2H), 2.62-2.72 (m, 6H), 3.57-3.59 (m, 4H), 4.13 (t, 2H, J=14 Hz), 6.20 (s, 1H), 6.79-6.82 (m, 2H), 6.90 (d, 1H, J=2 Hz), 7.36-7.51 (m, 8H), 7.81 (d, 1H, J=8 Hz), 7.92 (d, 1H, J=8 Hz) MS (ESI) m/z 498.3 ([M+H] + ) Example 13 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-phenyl-2H-benzopyran-2-one (13) The target compound was prepared according to the procedures of Example 11, using 1,4-dibromobutane instead of 1,3-dibromopropane. Melting point: 97-99° C. 1 H NMR (CDCl 3 ) δ 1.72-1.76 (m, 2H), 1.87-1.91 (m, 2H), 2.07-2.18 (m, 6H), 2.48 (t, 2H, J=14.8 Hz), 3.07-3.10 (m, 3H), 4.08 (t, 2H, J=12.4 Hz), 6.21 (s, 1H), 6.80-6.81 (m, 1H), 6.88-6.89 (m, 1H), 7.03-7.07 (m, 1H), 7.21-7.24 (m, 1H), 7.37-7.52 (m, 6H), 7.68-7.71 (m, 1H) MS (ESI) m/z 4514.3 ([M+H] + ) Example 14 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-phenyl-2H-benzopyran-2-one (14) The target compound was prepared according to the procedures of Example 12, using 1,4-dibromobutane instead of 1,3-dibromopropane. Melting point: 116-118° C. 1 H NMR (CDCl 3 ) δ 1.76-1.90 (m, 4H), 2.53 (t, 2H, J=14.8 Hz), 2.70-2.72 (m, 4H), 3.57-3.59 (m, 4H), 4.09 (t, 2H, J=12.4 Hz), 6.21 (s, 1H), 6.78-6.80 (m, 1H), 6.89 (d, 1H, J=2.4 Hz), 7.35-7.52 (m, 8H), 7.81 (d, 1H, J=8 Hz), 7.91 (d, 1H, J=8.4 Hz) MS (ESI) m/z 512.3 ([M+H] + ) Example 15 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one (15) 1) 30 ml of concentrated sulfuric acid was stirred in an ice bath, to which was added 5.5 g of resorcinol and was added 9.2 g of trifluoro ethyl acetoacetate dropwise. The solution turned yellow from yellowish. The reaction was carried out for 18 hours. The reaction liquid was poured into ice/water mixture, and a lot of solid was precipitated, which was filtrated. The cake was washed with water to neutral. Recrystallization with 75% ethanol gave 8.5 g of white crystal. Melting point: 218-220° C., yield: 73.9%. 2) 4.6 g of the product of step 1), 6 g of anhydrous potassium carbonate, 50 ml of acetone and 8.4 g of 1,3-dibromopropane were heated under reflux for 4 hours, and then cooled to room temperature and filtrated. The solvent was removed by rotation to give yellowish oil, which was passed through a column to give 5.6 g of white solid. Melting point: 72-74° C., yield: 80.1%. 3) To 0.5 g of the product of step 2) were added 0.6 g of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride, 2 g of anhydrous potassium carbonate, 0.2 g of potassium iodide and 25 ml of acetonitrile, and the mixture was heated under reflux for 12 hours, and then cooled to room temperature and filtrated. The solvent was removed by rotation to give yellowish oil, which was passed through a column to give 0.50 g of white solid. Melting point: 146-148° C., yield: 71.4%. 1 H NMR (CDCl 3 ) δ 2.04-2.23 (m, 8H), 2.60 (t, 2H, J=6.8 Hz), 3.07-3.13 (m, 3H), 4.15 (t, 2H, J=12.8 Hz), 6.12 (s, 1H), 6.90-6.95 (m, 2H), 7.03-7.08 (m, 1H), 7.23-7.26 (m, 1H), 7.61-7.71 (m, 2H) MS (ESI) m/z 491.3 ([M+H] + ) Example 16 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one (16) The target compound was prepared according to the procedures of Example 15, using 3-(1-piperazinyl)-1,2-benzisothiazole hydrochloride instead of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride. Melting point: 103-105° C. 1 H NMR (CDCl 3 ) δ 2.10-2.13 (m, 2H), 2.67-2.77 (m, 6H), 3.62 (br, 4H), 4.16 (t, 2H, J=12.4 Hz), 6.62 (s, 1H), 6.90-6.95 (m, 2H), 7.36-7.38 (m, 1H), 7.46-7.47 (m, 1H), 7.61-7.62 (m, 1H), 7.63-7.64 (m, 1H), 7.81-7.90 (m, 1H) MS (ESI) m/z 490.2 ([M+H] + ) Example 17 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one (17) The target compound was prepared according to the procedures of Example 15, using 1,4-dibromobutane instead of 1,3-dibromopropane. Melting point: 125-127° C. 1 H NMR (CDCl 3 ) δ 1.77-1.92 (m, 4H), 2.11-2.23 (m, 6H), 2.52 (t, 2H, J=14.8 Hz), 3.10-3.13 (m, 3H), 4.10 (t, 2H, J=12.4 Hz), 6.61 (s, 1H), 6.87-6.93 (m, 2H), 7.03-7.08 (m, 1H), 7.22-7.25 (m, 1H), 7.60-7.63 (m, 1H), 7.70-7.73 (m, 1H) MS (ESI) m/z 505.3 ([M+H] + ) Example 18 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-(trifluoromethyl)-2H-benzopyran-2-one (18) The target compound was prepared according to the procedures of Example 16, using 1,4-dibromobutane instead of 1,3-dibromopropane. Melting point: 93-95° C. 1 H NMR (CDCl 3 ) δ 1.76-1.77 (m, 2H), 1.89-1.91 (m, 2H), 2.52 (t, 2H, J=14.8 Hz), 2.70 (t, 4H, J=9.6 Hz), 3.58 (t, 4H, J=9.6 Hz), 4.10 (t, 2H, J=12.4 Hz), 6.61 (s, 1H), 6.87 (d, 1H, J=2.4 Hz), 6.90-6.93 (m, 1H), 7.35 (t, 1H, J=15.2 Hz), 7.46 (t, 1H, J=14.8 Hz), 7.61 (d, 1H, J=1.2 Hz), 7.63 (d, 1H, J=1.2 Hz) MS (ESI) m/z 504.3 ([M+H] + ) Example 19 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-methyl-8-chloro-2H-benzopyran-2-one (19) The target compound was prepared according to the procedures of Example 6, using 2-chlororesorcinol as starting material. Melting point: 128-130° C. 1 H NMR (CDCl 3 ) δ 1.78-1.80 (m, 2H), 1.93-2.15 (m, 8H), 2.41 (s, 3H), 2.50 (t, 2H, J=14.4 Hz), 3.07-3.10 (m, 3H), 4.19 (t, 2H, J=12.4 Hz), 6.15 (s, 1H), 6.92 (d, 1H, J=8.8 Hz), 7.02-7.07 (m, 1H), 7.22-7.28 (m, 1H), 7.46 (d, 1H, J=8.8 Hz), 7.68-7.71 (m, 1H) MS (ESI) m/z 485.2 ([M+H] + ) Example 20 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-methyl-8-chloro-2H-benzopyran-2-one (20) The target compound was prepared according to the procedures of Example 5, using 2-chlororesorcinol as starting material. Melting point: 133-135° C. 1 H NMR (CDCl 3 ) δ 1.79-1.85 (m, 2H), 1.93-1.98 (m, 2H), 2.39 (s, 3H), 2.55 (t, 2H, J=7.2 Hz), 2.72 (t, 2H, J=9.6 Hz), 3.58 (t, 4H, J=9.6 Hz), 4.18 (t, 2H, J=12.4 Hz), 6.14 (s, 1H), 6.88-6.91 (m, 1H), 7.33-7.37 (m, 1H), 7.43-7.48 (m, 2H), 7.80 (d, 1H, J=8.4 Hz), 7.90 (d, 1H, J=8 Hz) MS (ESI) m/z 484.2 ([M+H] + ) Example 21 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-methyl-8-chloro-2H-benzopyran-2-one (21) The target compound was prepared according to the procedures of Example 7, using 2-chlororesorcinol as starting material. Melting point: 185-187° C. 1 H NMR (CDCl 3 ) δ 2.07-2.20 (m, 8H), 2.41 (s, 3H), 2.64 (t, 2H, J=7.2 Hz), 3.08-3.10 (m, 3H), 4.24 (t, 2H, J=12 Hz), 6.17 (s, 1H), 6.94 (d, 1H, J=8.8 Hz), 7.05 (t, 1H, J=2 Hz), 7.25 (t, 1H, J=16 Hz), 7.46 (d, 1H, J=8.8 Hz), 7.66-7.70 (m, 1H) MS (ESI) m/z 471.2 ([M+H] + ) Example 22 7-(3-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-propoxy))-4-methyl-8-chloro-2H-benzopyran-2-one (22) The target compound was prepared according to the procedures of Example 8, using 2-chlororesorcinol as starting material. Melting point: 162-164° C. 1 H NMR (CDCl 3 ) δ 1.79-1.98 (m, 4H), 2.39 (s, 3H), 2.55 (t, 2H, J=7.2 Hz), 2.72 (t, 4H, J=9.6 Hz), 3.58 (t, 4H, J=9.6 Hz), 4.18 (t, 2H, J=12.4 Hz), 6.14 (s, 1H), 6.90 (d, 1H, J=8.8 Hz), 7.35 (t, 1H, J=14.8 Hz), 7.43-7.48 (m, 2H), 7.80 (d, 1H, J=8.4 Hz), 7.90 (d, 1H, J=8 Hz) MS (ESI) m/z 470.2 ([M+H] + ) Example 23 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4,8-dimethyl-2H-benzopyran-2-one (23) The target compound was prepared according to the procedures of Example 6, using 2-methylresorcinol as starting material. Melting point: 117-119° C. 1 H NMR (CDCl 3 ) δ 1.72-1.80 (m, 2H), 1.88-1.94 (m, 2H), 2.05-2.19 (m, 6H), 2.31 (s, 3H), 2.39 (s, 3H), 2.49 (t, 2H, J=14.8 Hz), 3.09 (d, 3H, J=10 Hz), 4.11 (t, 2H, J=12.4 Hz), 6.11 (s, 1H), 6.84 (d, 1H, J=8.8 Hz), 7.05 (t, 1H, J=2 Hz), 7.22-7.24 (m, 1H), 7.40 (d, 1H, J=8.8 Hz), 7.68-7.71 (m, 1H) MS (ESI) m/z 465.3 ([M+H] + ) Example 24 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-8-dimethyl-2H-benzopyran-2-one (24) The target compound was prepared according to the procedures of Example 5, using 2-methylresorcinol as starting material. Melting point: 106-108° C. 1 H NMR (CDCl 3 ) δ 1.73-1.86 (m, 4H), 2.05-2.17 (m, 9H), 2.36 (s, 3H), 2.48 (t, 2H, J=14.8 Hz), 3.07-3.10 (m, 3H), 4.05 (t, 2H, J=12.4 Hz), 6.78-6.86 (m, 2H), 7.02-7.07 (m, 1H), 7.21-7.24 (m, 1H), 7.48 (d, 1H, J=8.8 Hz), 7.68-7.71 (m, 1H) MS (ESI) m/z 464.3 ([M+H] + ) Example 25 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-n-propyl-2H-benzopyran-2-one (25) The target compound was prepared according to the procedures of Example 6, using ethyl butyrylacetate as starting material. Melting point: 139-141° C. 1 H NMR (CDCl 3 ) δ 1.00 (t, 3H, J=14.4 Hz), 1.64-1.69 (m, 2H), 1.93-2.22 (m, 6H), 2.64 (t, 2H, J=14.4 Hz), 3.00-3.74 (m, 9H), 4.04 (t, 2H, J=12.8 Hz), 6.05 (s, 1H), 6.71-6.78 (m, 2H), 7.05-7.23 (m, 2H), 7.80 (d, 1H, J=8 Hz), 7.91 (d, 1H, J=8 Hz) MS (ESI) m/z 479.3 ([M+H] + ) Example 26 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-n-propyl-2H-benzopyran-2-one (26) The target compound was prepared according to the procedures of Example 5, using ethyl butyrylacetate as starting material. Melting point: 114-116° C. 1 H NMR (CDCl 3 ) δ 1.04 (t, 3H, J=14.4 Hz), 1.69-1.90 (m, 6H), 2.51 (t, 2H, J=14.8 Hz), 2.67-2.71 (m, 6H), 3.56-3.58 (m, 4H), 4.06 (t, 2H, J=12.8 Hz), 6.11 (s, 1H), 6.81-6.86 (m, 2H), 7.28-7.52 (m, 3H), 7.80 (d, 1H, J=8 Hz), 7.91 (d, 1H, J=8 Hz) MS (ESI) m/z 478.3 ([M+H] + ) Example 27 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-ethyl-2H-benzopyran-2-one (27) The target compound was prepared according to the procedures of Example 6, using ethyl propionylacetate as starting material. Melting point: 96-98° C. 1 H NMR (CDCl 3 ) δ 1.32 (t, 3H, J=14.8 Hz), 1.74-1.90 (m, 4H), 2.06-2.16 (m, 6H), 2.48 (t, 2H, J=14.8 Hz), 2.75-2.81 (m, 2H), 3.05-3.10 (m, 3H), 4.07 (t, 2H, J=12.8 Hz), 6.14 (s, 1H), 6.82-6.87 (m, 2H), 7.03-7.07 (m, 1H), 7.23-7.25 (m, 1H), 7.52 (d, 1H, J=8.8 Hz), 7.68-7.71 (m, 1H) MS (ESI) m/z 465.3 ([M+H] + ) Example 28 7-(4-(4-(3-(1,2-benzisothiazole)-1-piperazinyl)-n-butoxy))-4-ethyl-2H-benzopyran-2-one (28) The target compound was prepared according to the procedures of Example 5, using ethyl propionylacetate as starting material. Melting point: 110-112° C. 1 H NMR (CDCl 3 ) δ 1.32 (t, 3H, J=14.8 Hz), 1.76-1.91 (m, 4H), 2.53 (t, 2H, J=14.4 Hz), 2.71-2.79 (m, 6H), 3.58 (br, 4H), 0.07 (t, 2H, J=12.4 Hz), 6.15 (s, 1H), 6.82-6.87 (m, 2H), 7.36 (t, 1H, J=14.8 Hz), 7.47 (t, 1H, J=14.8 Hz), 7.52 (d, 1H, J=8.8 Hz), 7.81 (d, 1H, J=8.4 Hz), 7.91 (d, 1H, J=8 Hz) MS (ESI) m/z 464.3 ([M+H] + ) Example 29 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-3,4-dimethyl-2H-benzopyran-2-one (29) The target compound was prepared according to the procedures of Example 6, using 2-methyl ethyl acetoacetate as starting material. Melting point: 106-108° C. 1 H NMR (CDCl 3 ) δ 1.73-1.86 (m, 4H), 2.05-2.17 (m, 9H), 2.36 (s, 3H), 2.48 (t, 2H, J=14.8 Hz), 3.07-3.10 (m, 3H), 4.05 (t, 2H, J=12.4 Hz), 6.78-6.86 (m, 2H), 7.02-7.07 (m, 1H), 7.21-7.24 (m, 1H), 7.48 (d, 1H, J=8.8 Hz), 7.68-7.71 (m, 1H) MS (ESI) m/z 464.3 ([M+H] + ) Example 30 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-hydroxymethyl-2H-benzopyran-2-one (30) The target compound was synthesized according to Scheme 3. 1) 50 ml of concentrated sulfuric acid was stirred in an ice bath, to which was added 5.5 g of resorcinol and added 8 g of 4-chloro ethyl acetoacetate dropwise. The solution turned yellowish and turbid slowly. The reaction was performed at room temperature overnight. The reaction liquid was poured into ice/water mixture, and a lot of white solid was precipitated, which was filtrated. The cake was washed with water. The cake was recrystallized with 40% ethanol to give 7.5 g of white crystal. Melting point: 183-185° C., yield: 84%. 2) 5 g of the product of step 1) was added to 300 ml of water, and the mixture was heated under reflux for 30 hours. After the reaction was completed, the reaction mixture was filtrated while it was warm. The filtrate was cooled with ice and the needle-shaped solid was precipitated. Standing for 1 hour allowed a lot of solid to precipitate, which was filtrated. The cake was washed with water, dried and recrystallized with 30% ethanol to give 4.1 g of white solid. Melting point: 212-214° C., yield: 91%. 3) 6 g of the product of step 2), 8 g of anhydrous potassium carbonate, 100 ml of acetone and 8 g of 1,3-dibromopropane were heated under reflux for 12 hours and then cooled to room temperature, and filtrated. The solvent was distilled to give yellowish oil, which was passed through a column to give 4.5 g of white solid. Yield: 72.68%. 4) To 0.62 g of the product of step 3) were added 0.6 g of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride, 2 g of anhydrous potassium carbonate, 0.2 g of potassium iodide and 25 ml of acetonitrile, and the mixture was heated under reflux for 12 hours, and then cooled to room temperature. The solvent was distilled and the residue was dissolved with dichloromethane, washed with water, dried with anhydrous magnesium sulfate, and filtrated. The solvent was distilled to give yellowish oil, which was passed through a column to give 0.3 g of white solid. Melting point: 144-146° C., yield: 33.7%. 1 H NMR (CDCl 3 ) δ 2.05-2.09 (m, 8H), 2.60 (t, 2H, J=14.4 Hz), 3.08-3.11 (m, 3H), 4.11 (t, 2H, J=12.8 Hz), 4.88 (s, 2H), 6.47 (s, 1H), 6.84-6.86 (m, 2H), 7.06-7.07 (m, 1H), 7.23-7.25 (m, 1H), 7.41-7.43 (m, 1H), 7.71-7.72 (m, 1H) MS (ESI) m/z 453.3 ([M+H] + ) Example 31 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-butoxy))-4-hydroxymethyl-2H-benzopyran-2-one (31) The target compound was prepared according to the procedures of Example 30, using 1,4-dibromobutane instead of 1,3-dibromopropane. Melting point: 160-162° C. 1 H NMR (CDCl 3 ) δ 1.73-1.89 (m, 4H), 2.08-2.17 (m, 6H), 2.49 (t, 2H, J=14.4 Hz), 3.08-3.11 (m, 3H), 3.62 (br, 1H), 4.05 (t, 2H, J=12.4 Hz), 4.88 (s, 2H), 6.46 (s, 1H), 6.83-6.85 (m, 2H), 7.03-7.08 (m, 1H), 7.23-7.25 (m, 1H), 7.42 (d, 1H, J=8.8 Hz), 7.68-7.72 (m, 1H) MS (ESI) m/z 467.3 ([M+H] + ) Example 32 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-2-hydroxylpropoxy))-4-methyl-2H-benzopyran-2-one (32) The target compound was synthesized according to Scheme 4. 3.2 g of 4-methyl-7-hydroxylcoumarin, 20 ml of epoxy chloropropane, 5 ml of 10% potassium hydroxide solution were added to 25 ml of ethanol and the mixture was heated under reflux for 4 hours, and then cooled to room temperature after the reaction was completed. The solvent was distilled and to the residue was added dichloromethane, washed with water and dried with anhydrous magnesium sulfate. The solvent was distilled to give solid, which was recrystallized with anhydrous ethanol to give 3 g of white solid. Yield: 71.8%. 0.84 g of the product of the first step and 0.83 g of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole were added to 50 ml of anhydrous methanol and the mixture was heated under reflux for 4 hours. White solid was precipitated. The reaction mixture was cooled to room temperature and filtrated. The cake was washed with cold methanol to give 1.2 g of white solid. Melting point: 183-185° C., yield: 66.8%. 1 H NMR (CDCl 3 ) δ 2.08-2.14 (m, 4H), 2.26-2.27 (m, 1H), 2.40 (s, 3H), 2.59-2.65 (m, 3H), 3.02-3.20 (m, 3H), 3.63 (br, 1H), 4.08-4.18 (m, 3H), 6.15 (s, 1H), 6.85 (d, 1H, J=2.8 Hz), 6.91-6.93 (m, 1H), 7.06-7.09 (m, 1H), 7.24-7.27 (m, 1H), 7.51 (d, 1H, J=8.8 Hz), 7.66-7.69 (m, 1H) MS (ESI) m/z 453.2 ([M+H] + ) Example 33 7-(3-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-2-hydroxylpropoxy))-4-phenyl-2H-benzopyran-2-one (33) The target compound was prepared according to the procedures of Example 32, using 4-phenyl-7-hydroxylcoumarin instead of 4-methyl-7-hydroxylcoumarin. Melting point: 193-195° C. 1 H NMR (CDCl 3 ) δ 2.08-2.14 (m, 4H), 2.24-2.27 (m, 1H), 2.52-2.68 (m, 3H), 3.02-3.21 (m, 3H), 3.63 (br, s, 1H), 4.09 (t, 2H, J=9.6 Hz), 4.17-4.18 (m, 1H), 6.23 (s, 1H), 6.84-6.87 (m, 1H), 6.93-6.94 (m, 1H), 7.05-7.10 (m, 1H), 7.24-7.27 (m, 1H), 7.39-7.51 (m, 6H), 7.66-7.69 (m, 1H) MS (ESI) m/z 515.3 ([M+H] + ) Example 34 7-(4-(4-(3-(6-fluoro-benzisoxazole)-1-piperidyl)-n-propoxy))-4-phenyl-benzopyran-2-one (34) The target compound was synthesized according to Scheme 5. 1) To 5.5 g of resorcinol, 7.4 g of cinnamic acid were added 200 ml of concentrated hydrochloric acid, to which was introduced hydrochloride gas. The mixture was heated under reflux for 6 hours and then cooled to room temperature. The solid was precipitated and filtrated. The cake was washed with water, dried under vacuum, recrystallized with toluene to give 8.1 g of white solid. Melting point: 104-106° C., yield: 67.5%. 2) 3.1 g of the product of step 1), 6 g of anhydrous potassium carbonate, 50 ml of acetone, 6 g of 1,4-dibromobutane were heated under reflux, being monitored with TLC. The reaction was completed after about 6 hours, and then the reaction mixture was cooled to room temperature, and filtrated. The solvent was removed by rotation to give yellowish oil, which was passed through a column to give 2.9 g of colorless oil. Yield: 60.4%. 3) To 1.8 g of product of step 2) were added 1.26 g of 6-fluoro-3-(4-piperidyl)-1,2-benzisoxazole hydrochloride, 2.6 g of anhydrous potassium carbonate, 0.3 g of potassium iodide and 30 ml of acetonitrile, and the mixture was heated under reflux for 12 hours. The reaction mixture was cooled to room temperature after the reaction was completed. The solvent was removed by rotation and a suitable amount of dichloromethane was added. The mixture was washed with water, and dried with anhydrous magnesium sulfate. The solvent was distilled to give yellowish oil, which was passed through a column to give 1.6 g of colorless oil. Yield: 65.0%. 1 H NMR (CDCl 3 ) δ 1.61-1.76 (m, 5H), 2.07-2.16 (m, 6H), 2.47 (t, 2H, J=14.8 Hz), 3.08-3.10 (m, 5H), 3.89 (t, 2H, J=12.4 Hz), 6.38-6.40 (m, 2H), 7.01-7.05 (m, 2H), 7.22-7.27 (m, 6H), 7.65-7.70 (m, 1H) MS (ESI) m/z 515.3 ([M+H] + ) TABLE 1 Numbering of the preferable compounds prepared in the Examples and the structures No. Compound Structure 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 B. Pharmacological Examples Example 35 Preparation of 5HT 1A Membrane Rats were sacrificed by cervical dislocation on ice. Brain striatum was rapidly taken, and 2 brain striatums were combined into a centrifuge tube, to which 3 ml of buffer (0.05 M Tris-HCl buffer, containing 0.1% ascorbic acid, 10 μm pargyline and 4 mM CaCl 2 ) was added. Homogenization was conducted for 3-4 s at level 4 for four times, and then 5 ml of buffer was added (0.05 M Tris-HCl buffer, containing 0.1% ascorbic acid, 10 μm pargyline and 4 mM CaCl 2 ). Incubation at 37° C. was conducted for 10 min, the weight of the tubes were adjusted using a balance after incubation. Centrifugation was conducted at 12000 r, 4° C. for 20 min, the supernatant was discarded, and 3 ml of buffer was added (0.05 M Tris-HCl buffer, containing 0.1% ascorbic acid, 10 μm pargyline and 4 mM CaCl 2 ). Vortex mixer was used for blending, and then 5 ml of buffer was added (0.05 M Tris-HCl buffer, containing 0.1% ascorbic acid, 10 μm pargyline and 4 mM CaCl 2 ). Centrifugation was conducted and repeated 3 times. After the centrifugations, the supernatant was discarded, and the pellets were stored at −80° C. for future use. Materials for the Receptor Binding Assay Isotope ligand 3 H-8-OH-DPAT (67.0 Ci/mmol) was purchased from PerkinElmer Company; 5-HT was purchased from RBI Company; GF/C glass fiber filter paper was purchased from Whatman Company; Tris was imported and divided into aliquots; PPO, POPOP were purchased from Shanghai No. 1 Reagent Factory; lipid-soluble scintillation solution. Beckman LS-6500 Multi-function Liquid Scintillation Counter was used. Procedures (1) The prepared membrane was first applied with appropriate amount of homogenized liquid, and homogenizer was used for evenly dispersing. 15 tubes were mixed into a 100 ml container, and appropriate amount of homogenized liquid was added to give 50 ml of membrane suspension, which was reserved for future use. (2) 100 μL of membrane preparation and 100 μL of homogenized liquid were added into each reaction tube. (3) 100 μL of homogenized liquid was added into the total binding tube (TB), 100 μL of 5-HT (final concentration 10 −5 M) was added into the non-specific binding tube (NB), and 100 μL of the test compound (final concentration 10 −5 M) was added into the specific binding tube (SB) for each compound. (4) 10 μL of radioactive ligand 3 H-8-OH-DPAT was respectively added into each reaction tube (2 parallel tubes were used for each reaction tube, and each of them was placed on ice when adding sample). (5) Each reaction tube was incubated at 37° C. for 10 min; after the reaction was completed, the bound ligands were rapidly filtered under reduced pressure, and the ice-chilled assay buffer was used for adequate washing. The filter was taken out and put into a 3 ml scintillation vial, and 2 ml of toluene scintillation solution was added and blended. (6) The scintillation vials were put into Liquid Scintillation Counter for counting. Inhibition rate(1%)=(Total binding tube cpm−compound cpm)/(Total binding tube cpm−non-specific binding tube cpm)×100% Each assay for the compounds was conducted in duplicate. The results are listed in Table 2. Example 36 Preparation of 5HT 2A Membrane Rats were sacrificed by cervical dislocation on ice. Brain striatum was rapidly taken, and 2 brain striatums were combined into a centrifuge tube, to which 3 ml of buffer (0.05 M Tris-HCl buffer: 6.05 g of Tris was dissolved in 1000 ml of double-distilled water, and concentrated HCl was used to adjust to pH 7.5) was added, homogenization was conducted for 3-4 s at level 4 for four times, and then 5 ml of buffer was added. Incubation at 37° C. was conducted for 10 min, the weight of the tubes were adjusted using a balance after incubation. Centrifugation was conducted at 12000 r, 4° C. for 20 min, the supernatant was discarded, and 3 ml of buffer was added (0.05 M Tris-HCl buffer: 6.05 g of Tris was dissolved in 1000 ml of double-distilled water, and concentrated HCl was used to adjust to pH 7.5). Vortex mixer was used for blending, and then 5 ml of buffer was added. Centrifugation was conducted (repeated 3 times). After the centrifugations, the supernatant was discarded, and the pellets were stored at −80° C. for future use. Materials for the Receptor Binding Assay Isotope ligand [ 3 H]-Ketanserin (67.0 Ci/mmol) was purchased from PerkinElmer Company; Methysergide was purchased from RBI Company; GF/C glass fiber filter paper was purchased from Whatman Company; Tris was imported and divided into aliquots; PPO, POPOP were purchased from Shanghai No. 1 Reagent Factory; lipid-soluble scintillation solution. Beckman LS-6500 Multi-function Liquid Scintillation Counter was used. Procedures (1) The prepared membrane was first applied with homogenized liquid, and homogenizer was used for evenly dispersing. 15 tubes were mixed into a 100 ml container, and appropriate amount of homogenized liquid was added to give 50 ml of membrane suspension, which was reserved for future use. (2) 100 μL of membrane preparation and 100 μL of buffer were added into each reaction tube. (3) 100 μL of homogenized liquid was added into the total binding tube (TB), 100 μL of Methysergide (final concentration 10 −5 M) was added into the non-specific binding tube (NB), and 100 μL of the test compound (final concentration 10 −5 M) was added into the specific binding tube (SB) for each compound. (4) 10 μL of radioactive ligand 3 H-Ketanserin was respectively added into each reaction tube (2 parallel tubes were used for each reaction tube, and each of them was placed on ice when adding sample). (5) Each of the reaction tubes was incubated at 37° C. for 15 min. After the reaction was completed, the bound ligands were rapidly filtered under reduced pressure, and the ice-chilled assay buffer was used for adequate washing. The filter was taken out and put into a 3 ml scintillation vial, and 2 ml of toluene scintillation solution was added and blended. (6) The scintillation vials were put into Liquid Scintillation Counter for counting. Inhibition rate(1%)=(Total binding tube cpm−compound cpm)/(Total binding tube cpm−non-specific binding tube cpm)×100% Each assay for the compounds was conducted in duplicate. The results are listed in Table 2. Example 37 Preparation of D 2 Membrane Rats were sacrificed by cervical dislocation on ice. Brain striatum was rapidly taken, and 2 brain striatums were combined into a centrifuge tube, to which 3 ml of buffer (0.05 M Tris-HCl buffer, containing NaCl 120 mM, KCl 5 mM, MgCl 2 1 mM, CaCl 2 1 mM) was added, homogenization was conducted for 3-4 s at level 4 for four times, and then 5 ml of buffer was then added. The weight of the homogenized tubes were adjusted using a balance, and centrifugation was conducted at 12000 r, 4° C. for 20 min. The supernatant was discarded, and 3 ml of buffer was added (0.05 M Tris-HCl buffer, containing NaCl 120 mM, KCl 5 mM, MgCl 2 1 mM, CaCl 2 1 mM). Vortex mixer was used for blending, and then 5 ml of buffer was added (0.05 M Tris-HCl buffer, containing NaCl 120 mM, KCl 5 mM, MgCl 2 1 mM, CaCl 2 1 mM). Centrifugation was conducted (repeated 3 times). After the centrifugations, the supernatant was discarded, and the pellets were stored at −80° C. for future use. Materials for the Receptor Binding Assay Isotope ligand 3 H-Spiperone (67.0 Ci/mmol) was purchased from PerkinElmer Company; Butaclamol was purchased from RBI Company; GF/C glass fiber filter paper was purchased from Whatman Company; Tris was imported and divided into aliquots; PPO, POPOP were purchased from Shanghai No. 1 Reagent Factory; lipid-soluble scintillation solution. Beckman LS-6500 Multi-function Liquid Scintillation Counter was used. Procedures (1) The prepared membrane was first applied with appropriate amount of homogenized liquid, and homogenizer was used for evenly dispersing. 15 tubes were mixed into a 100 ml container, and appropriate amount of homogenized liquid was added to give 50 ml of membrane suspension, which was reserved for future use. (2) 100 μL of membrane preparation and 100 μL of buffer were added into each reaction tube. (3) 100 μL of homogenized liquid was added into the total binding tube (TB), 100 μL of Butaclamol (final concentration 10 −5 M) was added into the non-specific binding tube (NB), and 100 μL of the test compound (final concentration 10 −5 M) was added into the specific binding tube (SB) for each compound. (4) 10 μL of radioactive ligand 3 H-Spiperone was respectively added into each reaction tube (2 parallel tubes were used for each reaction tube, and each of them was placed on ice when adding sample). (5) Each of the reaction tubes was incubated at 37° C. for 20 min. After the reaction was completed, the bound ligands were rapidly filtered under reduced pressure, and the ice-chilled assay buffer was used for adequate washing. The filter was taken out and put into a 3 ml scintillation vial, and 2 ml of toluene scintillation solution was added and blended. (6) The scintillation vials were put into Liquid Scintillation Counter for counting. Inhibitory rate(1%)=(Total binding tube cpm−compound cpm)/(Total binding tube cpm−non-specific binding tube cpm)×100% Each assay for the compounds was conducted in duplicate. The results are listed in Table 2. Example 38 D 3 Receptor Assay Cells In HEK-293 cells, after 48-72 hours, receptor proteins were expressed on membrane in large amount. After the cells were centrifuged at 1000 rpm for 5 min, the supernatant was discarded, and the cell pellet was collected and stored in a −20° C. fridge for reservation. It was re-suspended with Tris-Cl (pH 7.4) in the assay. Materials for the Assay D 3 receptor isotope ligand [3H]-Spiperone was purchased from Amersham Company; (+)Butaclamol was purchased from RBI Company; GF/C glass fiber filter paper was purchased from Whatman Company; lipid-soluble scintillation solution. Tris was divided into aliquots by Genetimes Technology Inc. Procedures Competitive binding test for receptors: 20 μl of each of the test compounds and 20 μl of the radioactive ligand together with 160 μl of the receptor proteins were added into the reaction tubes, and the final concentrations of the test compound and the positive drug were all 10 μmol/L. After 50 min of incubation in 30° C. water bath, the tubes were immediately moved to ice bath to terminate the reactions. GF/C glass fiber filter papers were used for rapid sucking filtration on a Millipore cell sample collector, elution buffer (50 mM Tris-HCl, PH 7.4) was applied for 3 ml×3 times, and microwave was applied for 4-5 min for drying. The filter papers were moved into 0.5 ml centrifuge tubes, and 500 μl of lipid-soluble scintillation solution was added. The tubes were allowed to stand still for over 30 min in dark, and the intensities of radioactivity were measured by a counter. The percentage inhibition rates of each compound against the binding of isotope ligands were calculated according to the following formula: Inhibition rate(1%)=(Total binding tube cpm−compound cpm)/(Total binding tube cpm−non-specific binding tube cpm)×100% The results are listed in Table 2. Example 39 Preparation of 5HT 2C Membrane Rats were sacrificed by cervical dislocation on ice. Brain striatum was rapidly taken, and 2 brain striatums were combined into a centrifuge tube, to which 3 ml of buffer (0.05 M Tris-HCl buffer: 6.05 g of Tris was dissolved in 1000 ml of double-distilled water, and concentrated HCl was used to adjust to pH 7.5) was added, homogenization was conducted for 3-4 s at level 4 for four times, and then 5 ml of buffer was added. Incubation at 37° C. was conducted for 10 min, the weight of the tubes were adjusted using a balance after the incubation. Centrifugation was conducted at 12000 r, 4° C. for 20 min, the supernatant was discarded, and 3 ml of buffer was added (0.05 M Tris-HCl buffer: 6.05 g of Tris was dissolved in 1000 ml of double-distilled water, and concentrated HCl was used to adjust to pH 7.5). Vortex mixer was used for blending, and then 5 ml of buffer was added. Centrifugation was conducted (repeated 3 times). After the centrifugations, the supernatant was discarded, and the pellets were stored at −80° C. for future use. Materials for the Receptor Binding Assay Isotope ligand [ 3 H]-mesulergine (67.0 Ci/mmol) was purchased from PerkinElmer Company; mianserin was purchased from RBI Company; GF/C glass fiber filter paper was purchased from Whatman Company; Tris was imported and divided into aliquots; PPO, POPOP were purchased from Shanghai No. 1 Reagent Factory; lipid-soluble scintillation solution. Beckman LS-6500 Multi-function Liquid Scintillation Counter was used. Procedures (1) The prepared membrane was first applied with appropriate amount of homogenized liquid, and homogenizer was used for evenly dispersing. 15 tubes were mixed into a 100 ml container, and appropriate amount of homogenized liquid was added to give 50 ml of membrane suspension, which was reserved for future use. (2) 100 μL of membrane preparation and 100 μL of buffer were added into each reaction tube. (3) 100 μL of homogenized liquid was added into the total binding tube (TB), 100 μL of mianserin (final concentration 10 −5 M) was added into the non-specific binding tube (NB), and 100 μL of the test compound (final concentration 10 −5 M) was added into the specific binding tube (SB) for each compound. (4) 10 μL of radioactive ligand [ 3 H]-mesulergine was respectively added into each reaction tube (2 parallel tubes were used for each reaction tube, and each of them was placed on ice when adding sample). (5) Each of the reaction tubes was incubated at 37° C. for 15 min. After the reaction was completed, the bound ligands were rapidly filtered under reduced pressure, and the ice-chilled assay buffer was used for adequate washing. The filter was taken out and put into a 3 ml scintillation vial, and 2 ml of toluene scintillation solution was added and blended. (6) The scintillation vials were put into Liquid Scintillation Counter for counting. Inhibition rate(1%)=(Total binding tube cpm−compound cpm)/(Total binding tube cpm−non-specific binding tube cpm)×100% Each assay for the compounds was conducted in duplicate. The results are listed in Table 2. The results of in vitro assay indicated that, compounds 1, 6, 7, 12, 18 and 22 have relatively stronger affinities for four receptors (D 2 , D 3 , 5-HT 1A and 5-HT 2A ) while lower affinities for 5-HT 2C . Example 40 MK-801 Induced High Activity—the In Vivo Anti-Schizophrenia Activity of the Compounds Animals and Reagents Healthy mice of Kunming breed (with half male and half female, (20±2)g) were provided by Qinglongshan Animal Cultivation Center, Nanjing. Ascorbic acid was provided by Sinopharm Chemical Reagent Co. Ltd. MK-801 was produced by Sigma Company, USA; the formulation method: 0.1% vitamin C was used to formulate a 1 mg/ml solution. Test positive drugs: haloperidol, clozapine, risperidone, olanzapine, aripiprazole, ziprasidone, quetiapine. Tween 80, with the concentration of 10%. Procedures Mice with qualified body weight were selected, and randomly divided into blank group, model group, positive control group (risperidone group) and drug group. 10% Tween was administered intragastrically to the blank group and the model group at 0.1 ml/10 g; risperidone was administered intragastrically to the positive control group at 0.1 mg/kg; and corresponding amounts of drugs were administered intragastrically to the drug groups, respectively. 1 h after the administration, 0.1% of ascorbic acid was intraperitoneally injected to the blank group at 0.1 ml/10 g; and the model group, the positive control group (30 min) and the drug group were intraperitoneally injected the MK-801 solution at 0.1 mg/kg. Subsequently, the spontaneous activities of the mice of each group in 90 min were measured. The results are listed in Table 3. The results of this assay indicate that, when compared to the model group, risperidone, compound 19 and 23 can not only significantly improve the MK-801 induced high activity, but also effectively improve the apomorphine induced clambering symptoms, and they did not cause EPS at effective dosage, indicating that they have notable anti-schizophrenia effects. Example 41 Apomorphine Induced Clambering Assay of Mice Animals Healthy KM mice (male, with body weight of 18-22 g) were provided by Qinglongshan Animal Cultivation Center, Nanjing. Main Reagents Test positive drugs: haloperidol, clozapine, risperidone, olanzapine, aripiprazole, ziprasidone, quetiapine. Apomorphine provided by Sigma Company was dissolved in 0.9% NaCl (containing 0.1% vitamin C) before use, and was freshly formulated before use. Vitamin C, F20061113, was provided by Sinopharm Chemical Reagent Co. Ltd. Sodium chloride injection, H32026305, was provided by Xuzhou No. 5 Pharmaceutical Factory Co. Ltd. Instruments: self-made clambering cage, chronograph. Procedures: apomorphine induced clambering assay of mice KM mice (male, with body weight of 18-22 g) were randomly divided into negative control group, model group, positive drug groups for each dosage (risperidone, aripiprazole, ziprasidone, quetiapine, olanzapine, haloperidol, clozapine), and compound groups for each dosage (the specific dosages are listed in the following Table), with 10 mice in each group. Corresponding solvent double-distilled water was administered intragastrically to the negative control group and the model group, corresponding positive drugs were administered intragastrically to the positive drug groups (a small amount of acetic acid was first added and then double-distilled water was added when dissolving), and corresponding dosages of compounds were administered intragastrically to the compound groups for each dosage, with the volume for intragastric administration as 0.1 ml/10 g. 1 hour after the intragastric administration, apomorphine was subcutaneously injected (1 mg/kg), with the volume as 0.1 ml/10 g. After the injection of apomorphine, the mice were immediately put into the clambering cages. After 5 min of adaptation, the behaviors of the mice at 10-11, 20-21, and 30-31 min after the injection of apomorphine were observed and scored. Scoring criteria: 4 paws on the floor was scored as 0; 2 forepaws on the cage was scored as 1; and 4 paws on the cage was scored as 2. Example 42 Catalepsy Assay Animals Healthy mice of Kunming breed (with half male and half female, (22±2)g) were provided by Qinglongshan Animal Cultivation Center, Nanjing. Main reagents: the test drugs, haloperidol, clozapine, risperidone, olanzapine, aripiprazole, ziprasidone. Instruments: self-made bar-grabbing apparatus: stainless steel bar in mice box, which was 0.3 cm in diameter and 5 cm above the bench. Procedures KM mice (half male and half female, with body weight of 20-24 g) were randomly divided into negative control group, model group, positive drug groups for each dosage (risperidone, aripiprazole, ziprasidone, quetiapine, olanzapine, haloperidol, clozapine), and compound groups for each dosage, with 10 mice in each group. Corresponding solvent double-distilled water was administered intragastrically to the negative control group and the model group, corresponding positive drugs were administered intragastrically to the positive drug groups (a small amount of acetic acid was first added and then double-distilled water was added when dissolving), and corresponding dosages of compounds were administered intragastrically to the compound groups for each dosage, with the volume for intragastric administration as 0.1 ml/10 g. At 30 min, 60 min, 90 min after the intragastric administration, the two forepaws of the mice were gently placed on the bars (which were 20 cm in length, 0.3 cm in diameter, and 5.5 cm above the bench), and the hindpaws of the animals were placed on the bottom of the box. The durations for the mice to maintain the posture with the two forepaws on the bars were recorded, and 30 s of spasticity without moving was considered as the positive response. In the case the forepaws of the mice were not put down persistently, the observation was terminated at 60 s. The numbers of animals with positive response in each of the compound dosage groups were counted. Example 43 Acute Toxicity Study Limit Test of Sequential Assay KM mice (half male and half female) were randomly divided into several groups (with 2-5 mice in each group), which were respectively the 2000 mg/kg groups for each compound, and the solvent group. 0.2 ml/10 g were administered intragastrically. The death of the animals in 3 days were observed. (In the case 3 or more animals survived in 3 days without notable abnormity in their life states, the observation was continued until the assay was completed in 7 days. In the case 3 or more animals died in 3 days, the median lethal dose method was used to determine the LD 50 ). Pre-Assay for the Median Lethal Dose Method KM mice (half male and half female) were randomly divided into several groups (with 4 mice in each group), which were respectively the 1500 mg/kg, 1000 mg/kg, 500 mg/kg groups for each compound, and the solvent group. 0.2 ml/10 g were administered intragastrically, and the death of the animals in 1-3 days were observed. Results The LD 50 of single intragastric administration in mice was greater than 2000 mg/kg, which was comparable to aripiprazole (93 mg/kg) and ziprasidone (>2000 mg/kg), and was far greater than risperidone (82.1 mg/kg), indicating a relatively low acute toxicity. TABLE 2 The inhibition or IC 50 of the compounds for each receptor Compound D 2 5HT 1A inhibition % 5HT 2A inhibition % D 3 5HT 2C No. inhibition % or (IC 50 , nM) or (IC50, nM) inhibition % inhibition % 1 128.3% 9.61 a 1.53 a  97.6% 88.0% 2 80.6% 99.4% 103.4%  — — 3 106.3% 42.3% 101.2%  — — 4 49.2% 101.2%  59.1% — — 5 88.5% 113.5%  104.4%  — — 6 101.3% 3.52 a 0.39 a 100.4% 91.4% 7 102.8% 5.95 a 0.69 a 101.1% 82.0% 8 73.8% 98.5% 88.6% — — 9 102.4% 88.8% 119.6%  — — 10 111.2% 101.5%  109.1%  — — 11 18.5% 35.3% 57.8% — — 12 124.1% 127.3 a    9.26 a 103.1% 93.4% 13 65.2% 111.4%  67.2% — — 14 68.6% 95.5% 83.4% — — 15 94.6% 107.4%  83.3% — — 16 114.6% 104.1%  96.3% — — 17 92.3% 101.4%  95.9% — — 18 113.3% 6.19 a 0.79 a 103.3% 77.6% 19 27.8% 103.7%  119.2%  — — 20 9.7% 92.8% 15.5% — — 21 32.9% 100.8%  90.1% — — 22 111.8% 12.81 a   6.88 a 103.8% 99.8% 23 6.9% 78.5% 78.6% — — 24 98.1% 105.0%  97.4% — — 25 70.7% 84.5% 40.2% — — 26 61.9% 99.7% 128.9%  — — 27 84.0% 65.7% 123.6%  — — 28 58.8%   11% 56.1% — — 29 43.2% 97.1% 24.7% — — 30 20.3% 82.8% 98.5% — — 31 2.4% 63.9%  1.8% — — 32 62.6% 103.3%  157.1%  — — 33 110.5% 23.5% 128.6%  — — 34 119.6%  5.9% 115.4%  — — aripiprazole 94.9% 3.35 a 11.51 a   99.50% 99.8% Note: (“ a ” indicates that the data in the cell is IC 50 value) TABLE 3 Results of the in vivo animal model assay of the preferable compounds MK-801 apomorphine induced high induced catalepsy/ catalepsy/ activity clambering catalepsy MK-801 apomorphine Compoud LD 50 (ED 50 , po, (ED 50 , po, (ED 50 , po, induced high induced No. (po, mg/kg) mg/kg) mg/kg) mg/kg) activity clambering 1 >2000 0.61 0.32 1.41 2.35 4.41 6 >2000 0.32 0.11 0.68 2.13 6.18 7 1000-2000 0.27 0.15 1.50 5.56 10.00 19  >2000 1.33 1.68 70.85 53.27 42.17 23  >2000 4.24 0.21 46.14 10.88 219.71 haloperidol 20 7.42 0.10 0.44 4.40 4.89 clozapine 150 2.28 17.92 >50 >21.93 >5.58 risperidone 82.1 0.01 0.015 0.92 92.00 61.33 olanzapine 177 0.10 0.11 2.23 22.30 20.27 aripiprazole 93 0.12 0.66 2.40 20.00 11.43 ziprasidone >2000 0.56 0.37 30.40 54.29 82.16 quetiapine 800 10.1 2.02 800.00 79.21 396.04 C. Composition Example Example 44 Tablet Active Ingredient 100 mg (the compound according to the invention) microcrystalline cellulose 50 mg lactose 100 mg Povidone K30 9 mg carboxymethyl starch sodium 12 mg silica 2.5 mg magnesium stearate 1.5 mg The raw excipients were sieved with 80 mesh for use. The prescription doses of active ingredient, microcrystalline cellulose, lactose, Povidone K30 were weighed and introduced into a high speed mixing granulator, whereby they were mixed uniformly at low speed. A suitable amount of purified water was added, the stiffing was performed at low speed, and high speed shear granulation was carried out. The wet granules were dried at 60° C. for 3 hours, and sieved with 24 mesh. The prescription doses of carboxymethyl starch sodium, silica and magnesium stearate were added for mixing totally. The compression was performed in a rotary tablet press. Example 45 Capsule (230 mg) Active Ingredient 100 mg (the compound according to the invention) lactose 80 mg starch 40 mg Povidone K30 7 mg silica 2 mg magnesium stearate 1 mg The raw excipients were sieved with 80 mesh for use. The prescription doses of active ingredient, lactose, starch, Povidone K30 were weighed and introduced into a high speed mixing granulator, whereby they were mixed uniformly at low speed. A suitable amount of purified water was added, the stirring was performed at low speed, and high speed shear granulation was carried out. The wet granules were dried at 60° C. for 3 hours, and sieved with 24 mesh. The prescription doses of silica and magnesium stearate were added for mixing totally. The capsules were filled in a capsule filling machine.

The present invention relates to the field of pharmaceutical chemistry, and in particular, to a benzopyrone derivative and a use thereof. The benzopyrone derivative is compound having a structure of formula (I) or a pharmaceutically acceptable salt thereof. It has been found by experiments that, this type of compounds is useful in prevention or treatment of neuropsychical diseases.

BACKGROUND OF THE INVENTION [0001] Risperidone is a new serotonin/dopamine antagonist belonging to a new class, the benzisoxazole. The structure of risperidone is shown in Formula-1. It is used for the treatment of schizophrenia and psychotic disorder. DESCRIPTION OF THE PRIOR ART [0002] Risperidone was first disclosed in U.S. Pat. No. 4,804,663, according to which it may be prepared by the condensation of the benzisoxazole compound of Formula-2 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole in its free base form and the tetahydropyrimidine compound 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido-[1,2-a]pyrimidinone of Formula-3 in its hydrochloride salt form, in the presence of sodium carbonate as a base (condensing agent) and potassium iodide as a catalyst in dimethylformamide (DMF) medium (Scheme-1), followed by standard workup to get crude Risperidone, which is recrystallized in a mixture of dimethylformamaide and isopropyl alcohol to get pure Risperidone with an overall yield of 46%. [0003] WO-A-02/14256 and WO-A02/12200 disclose another process for producing risperidone, in which the condensation of the intermediates of Formula-2 and Formula-3, in their free base forms, is carried out in isopropyl alcohol or methylethylketone solvent medium, using sodium carbonate as a base (condensing agent). The overall yield as described here is 60%. [0004] Recently, WO-A-01/185731 describes a process for producing risperidone starting from the same two intermediates of Formula-2 and Formula-3, as free base, in the presence of sodium carbonate (condensing agent), but in water medium. Risperidone precipitates as a solid and is filtered and crystallised from dimethylformamide. The overall yield as described here is 65%. [0005] The benzisoxazole of Formula-2, 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole and tetrahydropyrimidine of Formula-3, 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido-[1,2-a]pyrimidin-4-one are basic nitrogen heterocyclic derivatives that are solids with low melting points. These two intermediates, in particular the tetrahydropyrimidine of Formula-3, are not stable, on account of their susceptibility to aerial oxidation. Therefore, these intermediates are usually isolated as acid addition salts, and are purified and stored as their acid addition salts, for example their hydrochloride salts. According to the above prior art processes, these acid addition salts have to be converted to the free base forms from the hydrochloride salts, before being subjected to condensation. These steps involve additional operations, which consume time and energy. Also, it is observed that impurities are formed while performing the set-free of said hydrochloride. [0006] The present invention addresses these drawbacks and provides a simple and efficient process for producing risperidone from the stable hydrochloride salts of the two intermediates of Formula-2 and Formula-3. Advantageously, the present invention allows risperidone to be produced by an easily operated process with minimal operation steps and a reduced effluent load. SUMMARY OF THE INVENTION [0007] Accordingly, the present invention provides a process for the preparation of risperidone of Formula-1: which process comprises reacting, in a condensation reaction, 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole monohydrochloride of Formula-2 with 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2,a]pyrimidin-4-one monohydrochloride of Formula-3: [0008] In a first embodiment, the condensation reaction is carded out in the presence of a base (condensing agent), in a solvent medium of water, one or more water-miscible solvents or a mixture of water and one or more water-miscible solvents, and the process comprises: [0009] a) carrying out the condensation reaction at a temperature in the range from 25 to 90° C.; [0010] (b) after completion of the condensation reaction, diluting the condensation reaction mass with ice-cold water to precipitate risperidone; [0011] (c) filtering and drying the precipitated risperidone to obtain crude risperidone; and [0012] (d) crystallizing the crude risperidone in an aqueous solvent to produce pure risperidone. [0013] In a second embodiment, the condensation reaction is carded out in the presence of a base (condensing agent), in a solvent medium of water, one or more water-miscible solvents or a mixture of water and one or more water-miscible solvents, and the process comprises: [0014] a) carrying out the condensation reaction at a temperature in the range from 25 to 90° C.; [0015] (b) after completion of the condensation reaction, then reaction mass is cooled to room temperature and diluting the condensation reaction mass with water to precipitate risperidone; [0016] (c) extracting the precipitated risperidone of step (b) with a water-immiscible solvent; [0017] (d) optionally subjecting the water-immiscible solvent extract to acid-base work-up followed by extraction with a water-immiscible solvent; [0018] (e) concentrating the extract resulting from step (c) or optional step (d) under reduced pressure to produce crude risperidone; and [0019] (f) crystallizing the crude risperidone in an aqueous solvent to produce pure risperidone. DETAILED DESCRIPTION OF THE INVENTION [0020] According to the first part of the process of the invention, the intermediates of Formula-2 and Formula-3, as their hydrochloride salts, are used for the condensation reaction, to form risperidone according to the Scheme 1: [0021] The condensation reaction is carried out in a solvent medium. The solvent medium may be water or one or more water-miscible organic solvents, or a mixture of water and one or more water-miscible organic solvents. Preferably the solvent medium is water or a mixture of water and acetonitrile. Most preferably, the solvent medium is a mixture of water and acetonitrile. [0022] The base (condensing agent) used according to the present invention may be an inorganic salt such as the carbonate, bicarbonate or hydroxide of an alkali metal or alkaline earth metal. Preferred as base is sodium carbonate or potassium carbonate, and most preferred as base is sodium carbonate. [0023] The mole ratio of the base (condensing agent) with respect to the hydrochloride salt of the compound of Formula-2 may be from 2.0:1 to 5.0:1, and more preferably is from 4.0:1 to 4.6:1. Most preferably, the rate is 4.3:1. [0024] The condensation reaction is carried out according to the present invention by dissolving or suspending both of the reactants and reagent in the solvent medium. The sequence of addition of the reactants and reagent is very important. The most preferred sequence is to dissolve or suspend the base (condensing agent) in a solvent medium as described above (preferably water or acetonitrile, more preferably acetonitrile), and then to add to this the hydrochloride salt of the compound of Formula-2. The hydrochloride salt of the compound of Formula -3 is dissolved in a solvent medium as described above (preferably water) and added to the reaction mixture. [0025] Preferably, the solution of the hydrochloride salt of the compound of Formula-3 is added over a period of 1 to 5 hours, and the most preferably is added over a period of 4 to 5 hours. The slow addition of the solution of the hydrochloride of the compound of Formula-3 to the reaction mixture is to avoid the decomposition of the intermediate of Formula-3 under the reaction conditions, and thus enhances the yield and quality of the product risperidone. [0026] The temperature of the reaction mixture during the addition of the solution of the hydrochloride salt of the compound of Formula- 3 is maintained in the range from 25 to 90° C. The temperature of the solution of the hydrochloride salt of the compound of Formula-3 being added is also preferably maintained in this temperature range. [0027] Thus, the condensation reaction is carried out at a temperature in the range from 25 to 90° C., preferably in the range from 40 to 90° C., and more preferably in the range from 50 to 75° C. [0028] After the completion of the addition of the solution of the hydrochloride salt of the compound of Formula-3 the reaction mixture is maintained in the range from 25 to 90° C., preferably in the range from 40 to 90< C., and more preferably in the range from 50 to 75° C., for an additional 2 to 10 hours, and preferably for an additional 4 to 8 hours. Most preferably the reaction mixture is stirred at the same temperature as that of the reaction mixture during the addition of the solution of the hydrochloride salt of the compound of Formula-3, for the additional hours. [0029] Finally the product is isolated by standard work-up, preferably by work-up (i) or (ii) as explained further below, and crystallised to produce pure risperidone as a crystalline solid: [0030] (i) A typical work-up may comprise of diluting the reaction mixture with ice-cold water to precipitate risperidone, filtering and drying the precipitated residue to obtain crude risperidone. [0031] (ii) Alternatively, the reaction mixture is cooled to room temperature and diluted with water to precipitate risperidone, and the precipitated risperidone is then extracted with a water-immiscible organic solvent such as methylene dichloride (i.e. dichloromethane), ethylene chloride, dichloroethane, ethyl acetate, toluene, benzene or chloroform, preferably methylene dichloride, to produce an organic extract. The organic extract is then worked up according to Method A or Method B explained below. [0032] According to Method A, the organic extract (preferably methylene dichloride) is washed with water, treated with activated carbon, and finally concentrated under reduced pressure to obtain crude risperidone. [0033] According to Method B, the organic extract (preferably methylene dichloride) is purified by typical acid-base work-up, preferably as follows: The organic extract (preferably methylene dichloride) is extracted with aqueous acid such as 10-25% aqueous acid, preferably 10-15% aqueous acid, for example formic acid, acetic acid, hydrochloric acid, hydrobromic acid or tartaric acid. Preferred is 10-15% aqueous hydrochloric acid. The aqueous acidic extract is optionally, but preferably, washed with organic solvent such as toluene, methylene dichloride, dichloroethane or ethyl acetate, or mixtures thereof, preferably methylene dichloride. The aqueous acidic extract is cooled to 15-25° C. and the pH adjusted to 8-9 at 15-25° C. by addition of a base such as aqueous sodium or potassium hydroxide, aqueous sodium or potassium carbonate or bicarbonate, or liquor ammonia solution. Most preferred as base is liquor ammonia solution. The resulting reaction mixture is extracted with a water-immiscible organic solvent such as methylene dichloride, ethylene chloride or chloroform, preferably with methylene dichloride. The organic (preferably methylene dichloride) extract is washed with water, treated with activated carbon and finally concentrated under reduced pressure to obtain crude risperidone worked up according to Method B. [0034] Then, the crude risperidone obtained from work-up (i) or from Method A or B in work-up (ii) is crystallised in an aqueous solvent, preferably 5-20% aqueous solvent, selected from aqueous acetone, aqueous methyl ethyl ketone, aqueous methyl isobutyl ketone, aqueous acetonitrile and aqueous dimethylformamide, preferably aqueous acetone, especially 10% aqueous acetone, to produce pure risperidone as a crystalline solid. By this method, it is possible to obtain directly a pharmaceutically acceptable grade of risperidone, for example having purity greater than 99% (as deterrmined by HPLC). [0035] The crystallisation is carried out in known manner, for example by dissolving the crude risperidone in the aqueous solvent at 50-70° to produce a clear solution, treating the solution wit activated carbon, filtering, cooling to 0-5° C., and then separating the pure risperidone by filtration. [0036] When crystallised from an aqueous ketonic solvent selected from aqueous acetone, aqueous methyl ethyl ketone and aqueous methyl isobutyl ketone, crystalline risperidone is obtained having a polymorphic form identical to that of risperidone obtained from /the inventors' recrystallizing process as disclosed in U.S. Pat. No. 4,804,663 i.e. crystallization from IPA/DMF mixture. This is confirmed by the X-ray diffraction (XRD) analysis as shown in FIG. 1 . This polymorphic form is designated as Form B in US-A-2002/0115672 (Mayers) and as Form A in WO-A-02/12200 (Teva). As shown by FIG. 1 , this polymorphic form has peaks at about 6.956, 10.630, 11.410, 14.188, 14.794, 15.428, 16.377, 18.453, 18.875, 19.750, 21.309, 22.121, 22.427, 23.152, 23.477, 24.303, 25.77, 27.507, 28.328, 28.965, 32.262, 33.005, 33.622, 38.488, 39.585, 42.705, 43.404 and 45.059±0.2 degrees two theta. [0037] Risperidone base, thus crystallized, may be converted to pharmaceutically acceptable non-toxic acid addition salts such as hydrochloride, tartrate or palmate salts, by conventional methods. [0038] The benzisoxazole compound of Formula-2 is preferably prepared according to the procedure described in the U.S. Pat. No. 4,355,037. [0039] The tetrahydropyrimidine compound of Formula-3 is preferably prepared by hydrogenation of the corresponding pyrimidine derivative 3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2,a]pyrimidin-4-one, preferably in methanol using a Raney nickel catalyst according to Scheme-2. [0040] The preferred hydrogenation reaction temperature is 28-35° C., and preferred hydrogen pressure 70-80 psi. The pyrimidine derivative itself prepared according to known procedures by the condensation of 2-aminopyridine with 2-acetylbutyrolactone. [0041] The present invention is further illustrated by the following non-limiting experimental examples: EXAMPLES [0000] Experimental Details for Preparation of Risperidone Example 1 Condensation Reaction in Water Medium [0042] 6-Fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride (Formula-2.HCl, 100 g) is added to a solution of sodium carbonate(180 g) in 400 ml water at 25-30° C. Slowly the reaction mass is warmed to 50-55° C. and then a solution of 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one hydrochloride (Formula-3.HCl, 150 g) in water (300 ml) is added gradually over a period of 5 hours at 50-55° C. The reaction mass temperature is maintained further for another 4 hours. The reaction mass is cooled to room temperature and diluted with (200 ml) water the precipitated risperidone is separated by filtration, washed with water (50 ml) and dried to get crude risperidone. [0043] Crude risperidone weight=135 gm [0044] Purity=90-95% (HPLC) Example 2 Condensation Reaction in Water Medium [0045] 6-Fluoro-3-(4-piperidinyl)-1,2-benzisoxazole hydrochloride (Formula-2.HCl, 100 g) is added to a solution of sodium carbonate(180 g) in 400 mi water at 25-30° C. Slowly the reaction mass is warmed to 50-55° C. and then a solution of 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one hydrochloride (Formula-3.HCl, 150 g) In water (300 ml) is added gradually over a period of 5 hours at 50-55° C,. The reaction mass temperature Is maintained further for another 4 hours. The reaction mass is cooled to room temperature and diluted with (200 ml) water the precipitated risperidone is extracted with dichloromethane (3×450 ml). The dichloromethane extract is used for further work-up according to Method A or Method B, as given below to get crude risperidone. Example 3 Condensation Reaction in Mixture of Water and Water-Miscible Solvents [0046] 6-fluoro-3-(4-piperidinyl)-1,2 benzisoxazole hydrochloride (100 g) is added to a suspension of sodium carbonate (180 g) in acetonitle (500 ml) at 25-30° C. Slowly, the reaction mass is warmed to 70-75° C. and then a solution of 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one hydrochloride (110 g) in water (200 ml) is added gradually over a period of 4 hours at 70-75° C. The reaction mass is maintained at the same temperature for an additional 4 hours. The reaction mass is then cooled to room temperature and diluted with water (500 ml). The resulting mixture is extracted with dichloromethane (3×450 ml). The dichloromethane extract is worked up as explained for Method A in Example 1 to produce crude risperidone [0047] Method A: The dichloromethane extract is washed with 2×150 ml of water, treated with activated carbon, and concentrated under reduced pressure to produce crude risperidone. [0048] Crude risperidone: 190-200 g [0049] Purity: ˜85-90% (HPLC) [0050] Method B: The dichloromethane extract is extracted with aqueous dilute hydrochloric acid (10%). The aqueous extract is washed with dichloromethane (200 ml) and basified with aqueous ammonia to pH 8.5-9.0. The aqueous mass is extracted with dichloromethane (3×450 ml), and the dichloromethane extract is washed with water, treated with activated carbon and then concentrated under reduced pressure to produce crude risperidone. [0051] Crude risperidone: 180-190 g [0052] Purity: ˜87-92%(HPLC) Example 4 Purification of Crude Risperidone [0053] A) From 10% Aqueous Acetone: [0054] Risperidone crude (100 g) is dissolved in 10% aqueous acetone (700 ml) at 50-55° C., then treated with 10% activated carbon and filtered. The clear filtrate is gradually cooled to 0-5° C. over a period of 45 hours . The crystallized risperidone is separated by filtration and washed with chilled 10% aqueous acetone followed by drying at 50-55° C. under vacuum to get pure risperidone. [0055] Pure risperidone: 75-80 g. [0056] Purity: >99%( HPLC) [0057] B) From 10% aqueous acetonitrile: [0058] Risperidone crude (100 g) is dissolved in 10% aqueous acetonitile (500 ml) at 65-70° C., then treated with 10% activated carbon and filtered. The clear filtrate is gradually cooled to 0-5° C. over a period of 45 hours. The crystallized risperidone is separated by filtration and washed with chilled 10% aqueous acetontrile followed by drying at 50-55° C. under vacuum to get pure risperidone. [0059] Pure risperidone: 80-85 g Purity: >99% (HPLC) [0060] C) From 10% aaueous methvl ethyl ketone: [0061] Risperidone crude (100 g) is dissolved in 10% aqueous methyl ethyl ketone (600 ml) at 65-70° C., then treated with 10% activated carbon and filtered. The clear filtrate is gradually cooled to 0-5° C. over a period of 4-5 hours. The crystallized risperidone is separated by filtration and washed with chilled 10% aqueous methyl ethyl ketone followed by drying at 50-55° C. under vacuum to get pure risperidone. [0062] Pure risperidone: 65-70 g [0063] Purity. >99% (HPLC) [0064] D) From 5% aqueous isobutyl methyl ketone: [0065] Risperidone crude (100 g) is dissolved in 5% aqueous isobutyl methyl ketone (650 ml) at 65-70° C., then treated with 10% activated carbon and filtered. The clear filtrate is gradually cooled to 0-5° C. over a period of 4-5 hours. The crystallized risperidone is separated by filtration and washed with chilled 10% aqueous isobutyl methyl ketone followed by drying at 50-55° C. under vacuum to get pure risperidone. [0066] Pure risperidone: 60-65 g [0067] Purity: >99%( HPLC) [0068] Crude risperidone is prepared using the same procedure as described in Example-3, but using different solvent media and temperature as given in Table-1, Instead of acetonitrile (500 ml) /water (200 ml) at 70-75° C. in Example-3, in the condensation reaction to get crude risperidone. The above isolated crude risperidone is purified as disclosed in Example-4 ;A,B,C and D. [0069] The weights, yields & purities of pure risperidone (samples 1-8) are given in Table 1: Condensation Solvent used for reaction SI. condensation temperature Weight Purity Yield No reaction (° C.) (g) (%) (%) 1 Water 50-55 121 99.34 75.8% 2 Water:DMF 55-60 110 99.67 68.76%  (1.0:4.6 v/v) 3 Water:DMF 65-70 120 99.87   75% (1.0:7.0 v/v) 4 Water:IPA 60-65 80 99.67   50% (1.0:14.0 v/v) 5 Water:MeOH 60-65 80 99.74   50% (1.0:30.0 v/v) 6 Water:ACN 65-70 135 99.63 81.2% (1.0:4.0 v/v) 7 Ethanol 65-70 115 99.72 67.5% 8 DMF 65-70 60 98.77 37.5% Example 5 Preparation of 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one hydrochloride (Formula-3 (1):Preparation of 3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one [0070] 2-Aminopyridine (100 g) is added to a solution of toluene (100 ml) and phosphorus oxychloride (365 g) at 0-5° C. and then the temperature is raised to 50-55° C. 2-Acetylbutyrolactone (82 g) is added to the mixture at the same temperature. The temperature is raised to 90-95° C. and maintained for an additional 5 hours. Additional 2-acetylbutyrolactone (82 g) is added at this temperature and the temperature is further maintained for an additional 9-10 hours: Toluene and the excess phosphorus oxychloride is then distilled off under reduced pressure and the residue is quenched over ice-water mixture. The pH of the resulting aqueous mixture is adjusted to 89 with liquor ammonia and the precipitated solid is extracted with dichloromethane (3×200 ml). The organic extract is washed with water and then concentrated under reduced pressure to obtain a residue. The residue is triturated with isopropyl alcohol to produce 3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one. (2):Preparation of 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one hydrochloride (Formula-3) [0071] 3-(2-Chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one(100 gm) is taken in methanol(500 ml) in a pressure reactor and Raney nickel(10 g) added to it. The reactor is pressurised with hydrogen at 70-80 psi and the mixture is stirred at 28-35° C. until the hydrogen absorption ceases (approximately after 6 hours). The Raney nickel catalyst is then filtered. The pH of the filtrate is adjusted to 1.5-2.0 with concentrated hydrochloric acid (50-60 ml). Methanol is then distilled off under reduced pressure and isopropyl alcohol (500 ml) is added to the residue. The resulting slurry is cooled to 0-5° C. and the precipitated solid is filtered. The solid is washed with cold isopropyl alcohol and dried to produce 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido]1,2-a]pyrimidin-4-one hydrochloride of Formula-3. [0072] Yield: 90 g [0073] Purity: >98% (by HPLC)

A process is provided for the preparation of risperidone of Formula (1); which process comprises reacting, in a condensation reaction, 6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole monohydrochloride of Formula (2) with 3-(2-chloroethyl)-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2,a]pyrimidin-4-one monohydrochloride of Formula (3).

FIELD OF THE INVENTION The present invention relates to the field of printing. In particular, the invention concerns an inkjet printhead for high resolution printing. CROSS REFERENCE TO OTHER RELATED APPLICATIONS The following applications have been filed by the Applicant simultaneously with this application: 7,712,876 7,712,859 11/829,961 11/829,962 11/829,966 11/829,967 11/829,968 11/829,969 The disclosures of these co-pending applications are incorporated herein by reference. The following patents or patent applications filed by the applicant or assignee of the present invention are hereby incorporated by cross-reference. 6,405,055 6,628,430 7,136,186 7,286,260 7,145,689 7,130,075 7,081,974 7,177,055 7,209,257 7,161,715 7,154,632 7,158,258 7,148,993 7,075,684 7,564,580 11/650,545 7,241,005 7,108,437 6,915,140 6,999,206 7,136,198 7,092,130 7,249,108 6,566,858 6,331,946 6,246,970 6,442,525 7,346,586 7,685,423 6,374,354 7,246,098 6,816,968 6,757,832 6,334,190 6,745,331 7,249,109 7,197,642 7,093,139 7,509,292 7,685,424 10/866,608 7,210,038 7,401,223 7,702,926 7,716,098 11/706,329 11/757,385 7,657,488 7,170,652 6,967,750 6,995,876 7,099,051 7,453,586 7,193,734 11/209,711 7,468,810 7,095,533 6,914,686 7,161,709 7,099,033 7,364,256 7,258,417 7,293,853 7,328,968 7,270,395 7,461,916 7,510,264 7,334,864 7,255,419 7,284,819 7,229,148 7,258,416 7,273,263 7,270,393 6,984,017 7,347,526 7,357,477 11,748,482 7,562,960 11/779,851 7,524,017 7,465,015 7,364,255 7,357,476 11/003,614 7,284,820 7,341,328 7,246,875 7,322,669 11/764,760 7,445,311 7,452,052 7,455,383 7,448,724 7,441,864 7,637,588 7,648,222 7,669,958 7,607,755 7,699,433 7,658,463 7,344,226 7,328,976 11/685,084 7,669,967 11/685,090 11/740,925 7,605,009 7,568,787 11/518,238 11/518,280 7,663,784 11/518,243 11/518,242 7,331,651 7,334,870 7,334,875 7,416,283 7,438,386 7,461,921 7,506,958 7,472,981 7,448,722 7,575,297 7,438,381 7,441,863 7,438,382 7,425,051 7,399,057 7,695,097 7,686,419 11/246,669 7,448,720 7,448,723 7,445,310 7,399,054 7,425,049 7,367,648 7,370,936 7,401,886 7,506,952 7,401,887 7,384,119 7,401,888 7,387,358 7,413,281 7,530,663 7,467,846 7,669,957 11/482,963 11/482,956 7,695,123 11/482,974 7,604,334 11/482,987 7,708,375 7,695,093 7,695,098 11/482,964 7,703,882 7,510,261 11/482,973 7,581,812 7,641,304 11/495,817 6,227,652 6,213,588 6,213,589 6,231,163 6,247,795 6,394,581 6,244,691 6,257,704 6,416,168 6,220,694 6,257,705 6,247,794 6,234,610 6,247,793 6,264,306 6,241,342 6,247,792 6,264,307 6,254,220 6,234,611 6,302,528 6,283,582 6,239,821 6,338,547 6,247,796 6,557,977 6,390,603 6,362,843 6,293,653 6,312,107 6,227,653 6,234,609 6,238,040 6,188,415 6,227,654 6,209,989 6,247,791 6,336,710 6,217,153 6,416,167 6,243,113 6,283,581 6,247,790 6,260,953 6,267,469 6,588,882 6,742,873 6,918,655 6,547,371 6,938,989 6,598,964 6,923,526 6,273,544 6,309,048 6,420,196 6,443,558 6,439,689 6,378,989 6,848,181 6,634,735 6,299,289 6,299,290 6,425,654 6,902,255 6,623,101 6,406,129 6,505,916 6,457,809 6,550,895 6,457,812 7,152,962 6,428,133 7,216,956 7,080,895 7,442,317 7,182,437 7,357,485 7,387,368 11/607,976 7,618,124 7,654,641 11/607,980 7,611,225 11/607,978 11/735,961 11/685,074 7,637,582 7,419,247 7,384,131 11/763,446 7,416,280 7,252,366 7,488,051 7,360,865 11,766,713 11/482,980 11/563,684 11/482,967 11/482,966 11/482,988 7,681,000 7,438,371 7,465,017 7,441,862 7,654,636 7,458,659 7,455,376 11/124,158 11/124,196 11/124,199 11/124,162 11/124,202 11/124,197 11/124,198 7,284,921 11/124,151 7,407,257 7,470,019 7,645,022 7,392,950 11/124,149 7,360,880 7,517,046 7,236,271 11/124,174 11/124,194 11/124,164 7,465,047 7,607,774 11/124,166 11/124,150 11/124,172 11/124,165 7,566,182 11/124,185 11/124,184 11/124,182 7,715,036 11/124,171 11/124,181 7,697,159 7,595,904 11/124,191 11/124,159 7,466,993 7,370,932 7,404,616 11/124,187 11/124,189 11/124,190 7,500,268 7,558,962 7,447,908 11/124,178 7,661,813 7,456,994 7,431,449 7,466,444 11/124,179 7,680,512 11/187,976 11/188,011 7,562,973 7,530,446 7,628,467 11/228,540 11/228,500 7,668,540 11/228,530 11/228,490 11/228,531 11/228,504 11/228,533 11/228,502 11/228,507 7,708,203 11/228,505 7,641,115 7,697,714 7,654,444 11/228,484 7,499,765 11/228,518 11/228,536 11/228,496 7,558,563 11/228,506 11/228,516 11/228,526 11/228,539 11/228,538 11/228,524 11/228,523 7,506,802 11/228,528 11/228,527 7,403,797 11/228,520 7,646,503 11/228,511 7,672,664 11/228,515 11/228,537 11/228,534 11/228,491 11/228,499 11/228,509 11/228,492 7,558,599 11/228,510 11/228,508 11/228,512 11/228,514 11/228,494 7,438,215 7,689,249 7,621,442 7,575,172 7,357,311 7,380,709 7,428,986 7,403,796 7,407,092 11/228,513 7,637,424 7,469,829 11/228,535 7,558,597 7,558,598 6,087,638 6,340,222 6,041,600 6,299,300 6,067,797 6,286,935 6,044,646 6,382,769 6,787,051 6,938,990 7,588,693 7,416,282 7,481,943 7,678,667 7,152,972 7,513,615 6,746,105 11/763,440 11/763,442 11/246,687 7,645,026 7,322,681 7,708,387 11/246,703 7,712,884 7,510,267 7,465,041 11/246,712 7,465,032 7,401,890 7,401,910 7,470,010 11/246,702 7,431,432 7,465,037 7,445,317 7,549,735 7,597,425 7,661,800 7,712,869 7,156,508 7,159,972 7,083,271 7,165,834 7,080,894 7,201,469 7,090,336 7,156,489 7,413,283 7,438,385 7,083,257 7,258,422 7,255,423 7,219,980 7,591,533 7,416,274 7,367,649 7,118,192 7,618,121 7,322,672 7,077,505 7,198,354 7,077,504 7,614,724 7,198,355 7,401,894 7,322,676 7,152,959 7,213,906 7,178,901 7,222,938 7,108,353 7,104,629 7,455,392 7,370,939 7,429,095 7,404,621 7,261,401 7,461,919 7,438,388 7,328,972 7,322,673 7,306,324 7,306,325 7,524,021 7,399,071 7,556,360 7,303,261 7,568,786 7,517,049 7,549,727 7,399,053 11/737,080 7,467,849 7,556,349 7,648,226 11/782,593 7,303,930 7,401,405 7,464,466 7,464,465 7,246,886 7,128,400 7,108,355 6,991,322 7,287,836 7,118,197 7,575,298 7,364,269 7,077,493 6,962,402 7,686,429 7,147,308 7,524,034 7,118,198 7,168,790 7,172,270 7,229,155 6,830,318 7,195,342 7,175,261 7,465,035 7,108,356 7,118,202 7,510,269 7,134,744 7,510,270 7,134,743 7,182,439 7,210,768 7,465,036 7,134,745 7,156,484 7,118,201 7,111,926 7,431,433 7,018,021 7,401,901 7,468,139 7,128,402 7,387,369 7,484,832 11/490,041 7,506,968 7,284,839 7,246,885 7,229,156 7,533,970 7,467,855 7,293,858 7,520,594 7,588,321 7,258,427 7,556,350 7,278,716 11/603,825 7,524,028 7,467,856 7,469,996 7,506,963 7,533,968 7,556,354 7,524,030 7,581,822 7,533,964 7,549,729 7,448,729 7,246,876 7,431,431 7,419,249 7,377,623 7,328,978 7,334,876 7,147,306 7,261,394 7,611,218 7,637,593 7,654,645 11/482,977 7,491,911 11/764,808 09/575,197 7,079,712 6,825,945 7,330,974 6,813,039 6,987,506 7,038,797 6,980,318 6,816,274 7,102,772 7,350,236 6,681,045 6,728,000 7,173,722 7,088,459 7,707,082 7,068,382 7,062,651 6,789,194 6,789,191 6,644,642 6,502,614 6,622,999 6,669,385 6,549,935 6,987,573 6,727,996 6,591,884 6,439,706 6,760,119 7,295,332 6,290,349 6,428,155 6,785,016 6,870,966 6,822,639 6,737,591 7,055,739 7,233,320 6,830,196 6,832,717 6,957,768 7,456,820 7,170,499 7,106,888 7,123,239 7,468,284 7,341,330 7,372,145 7,425,052 7,287,831 10/727,162 7,377,608 7,399,043 7,121,639 7,165,824 7,152,942 10/727,157 7,181,572 7,096,137 7,302,592 7,278,034 7,188,282 7,592,829 10/727,180 10/727,179 10/727,192 10/727,274 7,707,621 7,523,111 7,573,301 7,660,998 10/754,536 10/754,938 10/727,160 7,171,323 7,278,697 7,360,131 7,519,772 7,328,115 11,749,750 11,749,749 7,369,270 6,795,215 7,070,098 7,154,638 6,805,419 6,859,289 6,977,751 6,398,332 6,394,573 6,622,923 6,747,760 6,921,144 10/884,881 7,092,112 7,192,106 7,457,001 7,173,739 6,986,560 7,008,033 7,551,324 7,222,780 7,270,391 7,525,677 7,388,689 7,398,916 7,571,906 7,654,628 7,611,220 7,556,353 7,195,328 7,182,422 11/650,537 11/712,540 7,374,266 7,427,117 7,448,707 7,281,330 10/854,503 7,328,956 10/854,509 7,188,928 7,093,989 7,377,609 7,600,843 10/854,498 10/854,511 7,390,071 10/854,525 10/854,526 7,549,715 7,252,353 7,607,757 7,267,417 10/854,505 7,517,036 7,275,805 7,314,261 7,281,777 7,290,852 7,484,831 10/854,523 10/854,527 7,549,718 10/854,520 7,631,190 7,557,941 10/854,499 10/854,501 7,266,661 7,243,193 10/854,518 10/934,628 7,163,345 7,322,666 7,566,111 7,434,910 11/735,881 11,748,483 11,749,123 11/766,061 7,465,016 11,772,235 11/778,569 7,543,808 11/544,764 11/544,765 11/544,772 11/544,774 11/544,775 7,425,048 11/544,766 11/544,767 7,384,128 7,604,321 11/544,769 7,681,970 7,425,047 7,413,288 7,465,033 7,452,055 7,470,002 11/293,833 7,475,963 7,448,735 7,465,042 7,448,739 7,438,399 11/293,794 7,467,853 7,461,922 7,465,020 11/293,830 7,461,910 11/293,828 7,270,494 7,632,032 7,475,961 7,547,088 7,611,239 11/293,819 11/293,818 7,681,876 11/293,816 7,703,903 7,703,900 7,703,901 11/640,358 11/640,359 11/640,360 11/640,355 11/679,786 7,448,734 7,425,050 7,364,263 7,201,468 7,360,868 7,234,802 7,303,255 7,287,846 7,156,511 10/760,264 7,258,432 7,097,291 7,645,025 10/760,248 7,083,273 7,367,647 7,374,355 7,441,880 7,547,092 10/760,206 7,513,598 10/760,270 7,198,352 7,364,264 7,303,251 7,201,470 7,121,655 7,293,861 7,232,208 7,328,985 7,344,232 7,083,272 7,311,387 7,303,258 11/706,322 7,517,050 7,708,391 11,779,848 7,621,620 7,669,961 7,331,663 7,360,861 7,328,973 7,427,121 7,407,262 7,303,252 7,249,822 7,537,309 7,311,382 7,360,860 7,364,257 7,390,075 7,350,896 7,429,096 7,384,135 7,331,660 7,416,287 7,488,052 7,322,684 7,322,685 7,311,381 7,270,405 7,303,268 7,470,007 7,399,072 7,393,076 7,681,967 7,588,301 7,249,833 7,547,098 7,703,886 7,524,016 7,490,927 7,331,661 7,524,043 7,300,140 7,357,492 7,357,493 7,566,106 7,380,902 7,284,816 7,284,845 7,255,430 7,390,080 7,328,984 7,350,913 7,322,671 7,380,910 7,431,424 7,470,006 7,585,054 7,347,534 7,441,865 7,469,989 7,367,650 11/778,567 7,469,990 7,441,882 7,556,364 7,357,496 7,467,863 7,431,440 7,431,443 7,527,353 7,524,023 7,513,603 7,467,852 7,465,045 11/688,863 11/688,864 7,475,976 7,364,265 11/688,867 11/688,868 11/688,869 11/688,871 11/688,872 7,654,640 11/741,766 7,645,034 7,637,602 7,645,033 7,661,803 11/495,819 11/677,049 11/677,050 7,658,482 7,306,320 7,111,935 7,562,971 10/760,219 7,604,322 7,261,482 10/760,220 7,002,664 10/760,252 7,088,420 11/446,233 7,470,014 7,470,020 7,540,601 7,654,761 7,377,635 7,686,446 7,237,888 7,168,654 7,201,272 6,991,098 7,217,051 6,944,970 10/760,215 7,108,434 7,210,407 7,186,042 10/760,266 6,920,704 7,217,049 7,607,756 10/760,260 7,147,102 7,287,828 7,249,838 10/760,241 7,431446 7,611,237 7,261,477 7,225,739 7,712,886 7,665,836 7,419,053 7,191,978 10/962,426 7,524,046 10/962,417 10/962,403 7,163,287 7,258,415 7,322,677 7,258,424 7,484,841 7,195,412 7,207,670 7,270,401 7,220,072 7,588,381 11/544,547 11/585,925 7,578,387 11/706,298 7,575,316 7,384,206 7,628,557 7,470,074 7,425,063 7,429,104 7,556,446 7,367,267 11/754,359 11/778,061 11/765,398 11/778,556 7,399,065 7,695,204 7,322,761 11/223,021 11/223,020 11/014,730 7,079,292 BACKGROUND OF THE INVENTION The quality of a printed image depends largely on me resolution of the printer. Accordingly, there are ongoing efforts to improve the print resolution of printers. The print resolution strictly depends on the spacing of the printer addressable locations on the media substrate and the drop volume. The spacing between nozzles on the printhead need not be as small as the spacing between addressable locations on the media substrate. The nozzle that prints a dot at one addressable location can be spaced any distance away from the nozzle that prints the dot at the adjacent addressable location. Movement of the printhead relative to the media, or vice versa, or both, will allow the printhead to eject drops at every addressable location regardless of the spacing between the nozzles on the printhead. In the extreme case, the same nozzle can print adjacent drops with the appropriate relative movement between the printhead and the media. Excess movement of the media with respect to the printhead will reduce print speeds. Multiple passes of a scanning printhead over a single swathe of the media, or multiple passes of the media past the printhead in the case of pagewidth printhead reduces the page per minute print rate. Alternatively, the nozzles can be spaced along the media feed path or in the scan direction so that the addressable locations on the media are smaller than the physical spacing of adjacent nozzles. It will be appreciated that the spacing the nozzles over a large section of the paper path or scan direction is counter to compact design. More importantly, it requires the paper feed to carefully control the media position and precise printer control of nozzle firing times. For pagewidth printheads, the large nozzle array emphasizes the problem. Spacing the nozzles over a large section of the paper path requires the nozzle array to have a relatively large area. The nozzle array must, by definition, extend the width of the media. But its dimension in the direction of media feed should be as small as possible. Arrays that extend a relatively long distance in the media feed direction require complex print platens that maintain the spacing between the nozzles and the media surface across the entire array. Some printer designs use a broad vacuum platen opposite the printhead to get the necessary control of the media. In light of these issues, there is a strong motivation to increase the density of nozzles on the printhead (that is, the number of nozzles per unit area) in order to increase the addressable locations of the printer and therefore the print resolution while keeping the width of the array (in the direction of media feed) small. SUMMARY OF THE INVENTION Accordingly, the present invention provides a printhead for an inkjet printer, the printhead comprising: an array of nozzles arranged in adjacent rows, each nozzle having an ejection aperture and a corresponding actuator for ejecting printing fluid through the ejection aperture, each actuator having electrodes spaced from each other in a direction transverse to the rows; and, drive circuitry for transmitting electrical power to the electrodes; wherein, the electrodes of the actuators in adjacent rows have opposing polarities such that the actuators in adjacent rows have opposing current flow directions. By reversing the polarity of the electrodes in adjacent rows, the punctuations in the power plane of the CMOS can be kept to the outside edges of the adjacent rows. This moves one line of narrow resistive bridges between the punctuations to a position where the electrical current does not flow through them. This eliminates their resistance from the actuators drive circuit. By reducing the resistive Josses for actuators remote from the power supply side of the printhead IC, the drop ejection characteristics are consistent, across the entire array of nozzles. Preferably, the electrodes in each row are offset from its adjacent actuators in a direction transverse to the row such that the electrodes of every second actuator are collinear. In a further preferred form, the offset is less than 40 microns. In a particularly preferred form, the offset is less than 30 microns. Preferably the array of nozzles is fabricated on an elongate wafer substrate extending parallel to the rows of the array, and the drive circuitry is CMOS layers on one surface of the wafer substrate, the CMOS layers being supplied with power and data along a long edge of the wafer substrate. In a further preferred form, the CMOS layers have a top metal layer forming a power plane that carries a positive voltage such that the electrodes having a negative voltage connect to vias formed in holes within the power plane. In another preferred form, the CMOS layers have a drive FET (field effect transistor) for each actuator in a bottom metal layer. Preferably, the CMOS layers have layers of metal less than 0.3 microns thick. In some embodiments, the actuators are heater elements for generating a vapor bubble in the printing fluid such that a drop of the printing fluid is ejected from the ejection aperture. Preferably, the heater elements are beams suspended between their respective electrodes such that they are immersed in the printing fluid. Preferably, the ejection apertures are elliptical with the major axis of the ejection aperture parallel to the longitudinal axis of the beam. In another preferred form, the major axes of the ejection apertures in one of the rows are respectively collinear with the major axes of the ejection apertures in the adjacent row such that each: of the nozzles in one of the rows is aligned with one of the nozzles in the adjacent tow. Preferably, the major axes of adjacent ejection apertures are spaced apart less than 50 microns. In a further preferred form, the major axes of adjacent ejection apertures are spaced apart less than 25 microns. In a particularly preferred form, the major axes of adjacent ejection apertures are spaced apart less than 16 microns. In particular embodiments, the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media iced direction. In preferred embodiments, the nozzle pitch is greater thaw 3000 npi. In a particularly preferred embodiment, the printhead has a print resolution in dots per inch (dpi) that equals the nozzle pitch. In specific embodiments, the printhead is a pagewidth printhead configured for printing A4 sized media. Preferably, the printhead has more than 100,000 of the nozzles. Accordingly, the present invention provides an inkjet printhead for a printer that can print onto a substrate at different print resolutions, the inkjet printhead comprising: an array of nozzles, each nozzle having an ejection aperture and a corresponding actuator for ejecting printing fluid through the ejection aperture; and, a print engine controller for sending print data to the array of nozzles; wherein, during use the print engine controller can selectively reduce the print resolution by apportioning print data for a single nozzle between at least two nozzles of the array. The invention recognizes that some print jobs do not require the printhead's best resolution—a lower resolution is completely adequate for the purposes of the document being printed. This is particularly true if the printhead is capable of very high resolutions, say greater than 1200 dpi. By selecting a lower resolution, the print engine controller (PEC) can treat two or more transversely adjacent (but not necessarily contiguous) nozzles as a single virtual nozzle in a printhead with less nozzles. The print data is then shared between the adjacent nozzles—dots required from the virtual nozzle are printed by each the actual nozzles in turn. This serves to extend the operational life of all the nozzles. Preferably, the two nozzles are positioned in the array such that they are nearest neighbours in a direction transverse to the movement of the printhead relative to the substrate. Preferably, the PEC shares the print data equally between the two nozzles in the array. In a further preferred form, the two nozzles are spaced at less than 20 micron centers. In a particularly preferred form, the printhead is a pagewidth printhead and the two nozzles are spaced in a direction transverse to the media iced direction at less than 16 micron centers. In a specific embodiments, the two nozzles are spaced in a direction transverse to the media feed direction at less than 8 micron centers. In particular embodiments, the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction. In preferred embodiments, the nozzle pitch is greater than 3000 npi. In a particularly preferred embodiment, the printhead has a print resolution in dots per inch (dpi) that equals the nozzle pitch. In specific embodiments, the printhead is configured for printing A4 sized media and the printhead has more than 100,000 of the nozzles. In some embodiments, the printer operates at an increased print speed when printing at the reduced print resolution. Preferably, the increased print speed is greater than 60 pages per minute. In preferred forms, the PEC halftones the color plane printed by the adjacent nozzles with a dither matrix optimized for the transverse shift of every drop ejected. Accordingly, the present invention provides an inkjet printhead comprising: an array of nozzles arranged in adjacent rows, each nozzle having an ejection aperture, a chamber for containing printing fluid and a corresponding actuator for ejecting the printing fluid through the ejection aperture, each of the chambers having a respective inlet to refill the priming fluid ejected by the actuator; and, a printing fluid supply channel extending parallel to the adjacent rows for supplying printing fluid to the actuator of each nozzle in the array via the respective inlets; wherein, the inlets of nozzles in one of the adjacent rows configured for a refill flowrate that differs from the refill flowrate through the inlets of nozzles in another of the adjacent rows. The invention configures the nozzle array so that several rows are filled from one side of an ink supply channel. This allows a greater density of nozzles on the printhead surface because the supply channel is not supplying just one row of nozzles along each side. However, the flowrate through the inlets is different for each row so that rows further from the supply channel do not have significantly longer refill times. Preferably, the inlets of nozzles in one of the adjacent rows configured for a refill flowrate that differs from the refill flowrate through the inlets of nozzles in another of the adjacent rows such that the chamber refill time is substantially uniform for all the nozzles in the array. In a further preferred form, the inlets of the row closest the supply channel are narrower than the rows further from the supply channel. In some embodiments, there are two adjacent rows of nozzles on either side of the supply channel. Preferably, the inlets have flow damping formations. In a particularly preferred form, the flow damping formation is a column positioned such that it creates a flow obstruction, the columns in the inlets of one row creating a different degree of obstruction to the columns is the inlets of the other row. Preferably, the columns create a bubble trap between the column sides and the inlet sidewalls. Preferably, the columns diffuse pressure pulses in the printing fluid to reduce cross talk between the nozzles. In some embodiments, the actuators are heater elements for generating a vapor bubble in the printing fluid such that a drop of the printing fluid is ejected from the ejection aperture. Preferably, the heater elements are beams suspended between their respective electrodes such that they are immersed in the printing fluid. Preferably, the ejection apertures are elliptical with the major axis of the ejection aperture parallel to the longitudinal axis of the beam. Preferably, the major axes of adjacent ejection apertures are spaced apart less than 50 microns. In a further preferred form, the major axes of adjacent ejection apertures are spaced apart less than 25 microns. In a particularly preferred form, the major axes of adjacent ejection apertures are spaced apart less than 16 microns. In particular embodiments, the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction. In preferred embodiments, the nozzle pitch is greater than 3000 npi. In a particularly preferred embodiment, the printhead has a print resolution in dots per inch (dpi) that equals the nozzle pitch. In specific embodiments, the printhead is a pagewidth printhead configured for printing A4 sized media. Preferably, the printhead has more than 100,000 of the nozzles. Accordingly, the present invention provides an inkjet printhead comprising: an array of nozzles arranged in a series of rows, each nozzle having an ejection aperture, a chamber for holding printing fluid and a heater element for generating a vapor bobble in the printing fluid contained by the chamber to eject a drop of the printing fluid through the ejection aperture; wherein, the nozzle, the heater element and the chamber are all elongate structures that have a long dimension that exceeds their other dimensions respectively; and, the respective long dimensions of the nozzle, the heater element and the chambers are parallel and extend normal to the row direction. To increase the nozzle density of the array, each of the nozzle components—the chamber, the ejection aperture and the heater element are configured as elongate structures that are all aligned transverse to the direction of the row. This raises the nozzle pitch, or nozzle per inch (npi), of the row while allowing the chamber volume and therefore drop volume to stay large enough for a suitable color density. It also avoids the need to spread the over a large distance in the paper feed direction (in the case of page-width primers) or in the scanning direction (in the case of scanning printheads). Preferably each of the rows in the array is offset with respect to it adjacent row such that none of the long dimensions of the nozzles in one row are not collinear with any of the long dimensions of the adjacent row. In a further preferred form the printhead is a pagewidth printhead for printing to a media substrate fed past the printhead in a media feed direction such that the long dimensions of the nozzles are parallel with the media feed direction. Preferably the long dimensions of the nozzles in every second are in registration. In a particularly preferred form the ejection apertures for all the nozzles is formed in a planar roof layer that partially defines the chamber, the roof layer having an exterior surface that is flat with the exception of the ejection apertures. In a particularly preferred form, the array of nozzles is formed on an underlying substrate extending parallel to the roof layer and the chamber is partially defined by a sidewall extending between the roof layer and the substrate, the side wall being shaped such that its interior surface is at least partially elliptical. Preferably, the sidewall is elliptical except for an inlet opening for the printing fluid. In a particularly preferred form, the minor axes of the nozzles in one of the rows partially overlaps with the minor axes of the nozzles in the adjacent row with respect to the media feed direction. In a further preferred form, the ejection apertures are elliptical. Preferably, the heater elements are beams suspended between their respective electrodes such that, during use, they are immersed in the printing fluid. Preferably, the vapor bubble generated by the heater element is approximately elliptical in a cross section parallel to the ejection aperture. In some embodiments, the printhead farther comprises a supply channel adjacent the array extending parallel to the rows. In a preferred form, the array of nozzles is a first array of nozzles and a second array of nozzles is formed on the other side of the supply channel, the second array being a mirror image of the first array but offset with respect to the first array such that none of the major axes of the ejection apertures in the first array are collinear with any of the major axes of the second array. Preferably, the major axes of ejection apertures in the first array are offset from the major axes of the ejection apertures in the second array in a direction transverse to the media feed direction by less than 20 microns. In a particularly preferred form, the offset is approximately 8 microns. In some embodiments, the printhead has a nozzle pitch in the direction transverse to the direction of media feed greater than 1600 npi. In a particularly preferred form, the substrate is less than 3 mm wide in the direction of media feed. Accordingly, the present invention provides an inkjet printhead comprising: an array of nozzles for ejecting drops of printing fluid onto print media when the print media and moved in a print direction relative to the printhead; wherein, the nozzles in the array are spaced apart from each other by less than 10 microns in the direction perpendicular to the print direction. With nozzles spaced less than 10 microns apart in the direction perpendicular to the print direction, the printhead has a very high ‘true’ print resolution—i.e. the high number of dots per inch is achieved by a high number of nozzles per inch. Preferably, the nozzles in the array that are spaced apart from each other by less than 10 microns in the direction perpendicular to the print direction, are also spaced apart from each other in the print direction by less than 150 microns. In a further preferred form, the array has more than 700 of the nozzles per square millimeter. Preferably, the array of nozzles is supported on a plurality of monolithic wafer substrates, each monolithic wafer substrate supporting more than 10000 of the nozzles. In a further preferred form, each monolithic wafer substrate supports more than 12000 of the nozzles. In a particularly preferred form, the plurality of monolithic wafer substrates are mounted end to end to form a pagewidth printhead for mounting is a printer configured to feed media past the printhead is a media feed direction, the printhead having more than 100000 of the nozzles and extends in a direction transverse to the media feed direction between 200 mm and 330 mm. In some embodiments, the array has more than 140000 of the nozzles. Optionally, the printhead further comprises a plurality of actuators for each of the nozzles respectively, the actuators being arranged in adjacent rows, each having electrodes spaced from each other in a direction transverse to the rows for connection to respective drive transistors and a power supply; wherein, the electrodes of the actuators in adjacent rows have opposing polarities such that the actuators in adjacent rows have opposing current flow directions. Preferably the electrodes in each row are offset front its adjacent actuators in a direction transverse to the row such that the electrodes of every second actuator are collinear. In particularly preferred embodiments, the droplet ejectors are fabricated on an elongate wafer substrate extending parallel to the rows of the actuators, and power and data supplied along a long edge of the wafer substrate. In some embodiments, the printhead has a print engine controller (PEC) for sending print data to the array of nozzles; wherein, during use the print engine controller can selectively reduce the print resolution by apportioning print data for a single nozzle between at least two nozzles of the array. Preferably, the two nozzles are positioned in the array such that they are nearest neighbours in a direction transverse to the movement of the printhead relative to a print media substrate. In a particularly preferred form, the PEC stores the print data equally between the two nozzles in the array. Preferably, the two nozzles are spaced at less than 40 micron centers. In a particularly preferred form, the printhead is a pagewidth printhead and the two nozzles are spaced in a direction transverse to the media feed direction at less than 16 micron centers. Preferably, the adjacent nozzles are spaced in a direction transverse to the media feed direction at less than 8 micron centers. Preferably, the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction. In a further preferred form, the nozzle pitch is greater than 3000 npi. Accordingly, the present invention provides a printhead integrated circuit for an inkjet printhead, the printhead integrated circuit comprising: a monolithic wafer substrate supporting an array of droplet ejectors for ejecting drops of printing fluid onto print media, each drop ejector having a nozzle and an actuator for ejecting a drop of printing fluid through the nozzle; wherein, the array has more than 10000 of the droplet ejectors. With a large number of droplet ejectors fabricated on a single wafer, the nozzle array has a high nozzle pitch and the printhead has a very high ‘true’ print resolution—i.e. the high number of dots per inch is achieved by a high number of nozzles per inch. Preferably, the array has more than 12000 of the droplet ejectors. In a further preferred form, the print media moves in a print direction relative to the printhead and the nozzles in the array are spaced apart from each other by less than 10 microns in the direction perpendicular to the print direction. In a particularly preferred form, the nozzles in the array that are spaced apart from each other by less than 10 microns in the direction perpendicular to the print direction, are also spaced apart front each other in the print direction by less than 150 microns. In a preferred embodiment, the array has more than 700 of the droplet ejectors per square millimeter. In a particularly preferred form, the actuators are arranged in adjacent rows, each having electrodes spaced from each other in a direction transverse to the rows for connection to respective drive transistors and a power supply, the electrodes of the actuators in adjacent rows having opposing polarities such that the actuators in adjacent, rows have opposing current flow directions. In a still farther preferred form, the electrodes in each row are offset from their adjacent actuators in a direction transverse to the row such that the electrodes of every second actuator are collinear. In specific embodiments, the monolithic wafer substrate is elongate and extends parallel to the rows of the actuators, such that in use power and data is supplied along a long edge of the wafer substrate. In some forms, the inkjet printhead comprises a plurality of the printhead integrated circuits, and further comprises a print engine controller (PEC) for sending print data to the array of droplet ejectors wherein during use the print engine controller can selectively reduce the print resolution by apportioning print data for a single droplet ejector between at least two droplet ejectors of the array. Preferably, the two nozzles are positioned in the array such that they are nearest neighbours in a direction transverse to the movement of the printhead relative to a print media substrate. In a particularly preferred form, the PEC shares the print data equally between the two nozzles in the array. Optionally, the two nozzles are spaced at less than 40 micron centers. In particularly preferred embodiments, the printhead is a pagewidth printhead and the two nozzles are spaced in a direction transverse to the media feed direction at less than 16 micron centers. In a still farther preferred form, the adjacent nozzles are spaced in a direction transverse to the media feed direction at less than 8 micron centers. In some embodiments, the inkjet printhead comprises a plurality of the printhead integrated circuits mounted end to end to form a pagewidth printhead for a printer configured to feed media past the printhead is a media feed direction, the printhead having more than 100000 of the nozzles and extends in a direction transverse to the media feed direction between 200 mm and 330 mm. In a further preferred form the array has more than 140000 of the nozzles. Preferably, the array of droplet ejectors has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction, and preferably the nozzle pitch is greater than 3000 npi. Accordingly, the present invention provides a printhead integrated circuit (IC) for an inkjet printhead, the printhead IC comprising: a planar array of droplet ejectors, each having data distribution circuitry, a drive transistor, a printing fluid inlet, an actuator, a chamber and a nozzle, the chamber being configured to hold printing fluid adjacent the nozzle such that during use, the drive transistor activates the actuator to eject a droplet of the printing fluid through the nozzle; wherein, the array has more than 700 of the droplet ejectors per square millimeter. With a high density of droplet ejectors fabricated on a wafer substrate, the nozzle array has a high nozzle pitch and the printhead has a very high ‘true’ print resolution—i.e. the high number of dots per inch is achieved by a high number of nozzles per inch. Preferably, the array ejects drops of printing fluid onto print media when the print media and moved in a print direction relative to the printhead, and the nozzles in the array are spaced apart from each other by less than 10 microns in the direction perpendicular to the print direction. In a further preferred form, the nozzles that are spaced apart from each other by less than 10 microns in the direction perpendicular to the print direction, are also spaced apart from each other in the print direction by less than 150 microns. In specific embodiments of the invention, a plurality of the printhead IC's are used in an inkjet printhead, each printhead IC having more than 10000 of the droplet ejectors, and preferably more than 12000 of the nozzle unit cells. In some embodiments, the printhead IC's are elongate and mounted end to end such that the printhead has more than 100000 of the droplet ejectors and extends in a direction transverse to the media feed direction between 200 mm and 330 mm. In a further preferred form, the printhead has more than 140000 of the droplet ejectors. In some preferred forms, the actuators are arranged in adjacent rows, each having electrodes spaced from each other in a direction transverse to the rows for connection to the corresponding drive transistor and a power supply; wherein, the electrodes of the actuators in adjacent rows have opposing polarities such that the actuators in adjacent rows have opposing current flow directions. Preferably, in these embodiments, the electrodes in each row are offset from its adjacent actuators in a direction transverse to the row such that the electrodes of even second actuator are collinear. In further preferred forms, the elongate wafer substrate extends parallel to the rows of the actuators, and power and date supplied along a long edge of the wafer substrate. In specific embodiments, the printhead has a print engine controller (PEC) for sending print data to the array of nozzles; wherein, during use the print engine controller can selectively reduce the print resolution by apportioning print data for a single nozzle between at least two nozzles of the array. Preferably, the two nozzles are positioned in the array such that they are nearest neighbours in a direction transverse to Use movement of the printhead relative to a print media substrate. In a further preferred form, the PEC shares the print data equally between the two nozzles in the array. Preferably, the two nozzles are spaced at less than 40 micron centers. In a particularly preferred form, the printhead is a pagewidth printhead and the two nozzles are spaced in a direction transverse to the media feed direction at less than 16 micron centers. In a still further preferred form, the adjacent nozzles are spaced in a direction transverse to the media, feed direction at less than 8 micron centers. In some forms, the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction. Preferably, the nozzle pitch is greater than 3000 npi. Accordingly, the present invention provides a pagewidth inkjet printhead comprising: an array of droplet ejectors for ejecting drops of printing fluid onto print media fed passed the printhead in a media feed direction, each drop ejector having a nozzle and an actuator for ejecting a drop of printing fluid through the nozzle; wherein, the array has more than 100000 of the droplet ejectors and extends in a direction transverse to the media feed direct between 200 mm and 330 mm. A pagewidth printhead with a large number of nozzles extending the width of the media provides a high nozzle pitch and a very high ‘true’ print resolution—i.e. the high number of dots per inch is achieved by a high number of nozzles per inch. Preferably, the array has more than 140000 of the droplet ejectors. In a farther preferred form, the nozzles are spiced apart from each other by less than 10 microns in the direction perpendicular to the media feed direction. In a particularly preferred form, the nozzles that are spaced apart front each other by less than 10 microns in the direction perpendicular to the media feed direction, are also spaced apart from, each other in the media feed direction by less than 130 microns. In specific embodiments, the array of droplet ejectors is supported on a plurality of monolithic wafer substrates, each monolithic wafer substrate supporting more than 10000 of the droplet ejectors, and preferably more than 12000 of the droplet ejectors. In these embodiments, it is desirable that the array has more than 700 of the droplet ejectors per square millimeter. Optionally, the actuators are arranged in adjacent rows, each having electrodes spaced from each other in a direction transverse to the rows for connection to respective drive transistors and a power supply; wherein, the electrodes of the actuators in adjacent rows have opposing polarities such that the actuators in adjacent rows lave opposing current flow directions. Preferably the electrodes in each row are offset from its adjacent actuators in a direction transverse to the row such that the electrodes of every second actuator are collinear. In particularly preferred embodiments, the droplet ejectors are fabricated on an elongate wafer substrate extending parallel to the rows of the actuators, and power and data supplied along a long edge of the wafer substrate. In some embodiments, the printhead has a print engine controller (PEC) for sending print data to the array of nozzles; wherein, during use the print engine controller can selectively reduce the print resolution by apportioning print data for a single nozzle between at least two nozzles of the array. Preferably, the two nozzles are positioned in the array such that they are nearest neighbours in a direction transverse to the movement of the printhead relative to a print media substrate. In a particularly preferred form, the PEC shares the print data equally between the two nozzles in the array. Preferably, the two nozzles are spaced at less than 40 micron centers. In a particularly preferred form, the printhead is a pagewidth printhead and the two nozzles are spaced in a direction transverse to the media feed direction at less than 16 micron centers. Preferably, the adjacent nozzles are spaced in a direction transverse to the media feed direction at less than 8 micron centers. Preferably, the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction. In a further preferred form, the nozzle pitch is greater than 3000 npi. Accordingly, the present invention provides a printhead integrated circuit for an inkjet printer, the printhead integrated circuit comprising: a monolithic wafer substrate supporting an array of droplet ejectors for ejecting drops of printing fluid onto print media, each droplet ejector having nozzle and an actuator for ejecting a drop of printing fluid the nozzle, the array being formed on the monolithic wafer substrate by a succession of photolithographic etching and deposition steps involving a photo-imaging device that exposes an exposure area to light focused to project a pattern onto the monolithic substrate; wherein, the array has more than 10000 of the droplet ejectors configured to be encompassed by the exposure area The invention arranges the nozzle array such that the droplet ejector density is very high and the number of exposure steps required is reduced. Preferably the exposure area is less than 900 mm 2 . Preferably, the monolithic wafer substrate is encompassed by the exposure area. In a further preferred form the photo-imaging device is a stepper that exposes an entire reticle simultaneously. Optionally, the photo-imaging device is a scanner that scans a narrow band of light across the exposure area to expose the reticle. Preferably, the monolithic wafer substrate supports mote than 12000 of the droplet ejectors. In these embodiments, it is desirable that the array has more than 700 of the droplet ejectors per square millimeter. In some embodiments, the printhead IC is assembled onto a pagewidth printhead with other like printhead IC's, for ejecting drops of printing fluid onto print media fed passed the printhead in a media feed direction, wherein, the printhead has more than 100000 of the droplet ejectors and extends in a direction transverse to the media feed direct between 200 mm and 330 mm. In a further preferred form, the nozzles are spaced apart from each other by less than 10 microns in the direction perpendicular to the media feed direction. Preferably, the printhead has more than 140000 of the droplet ejectors. In a particularly preferred form, the nozzles that are spaced apart from each other by less than 10 microns in the direction perpendicular to the media feed direction, are also spaced apart from each other in the media feed direction by less than 150 microns. Optionally, the actuators are arranged in adjacent rows, each having electrodes spaced from each other in a direction transverse to the rows for connection to respective drive transistors and a power supply; wherein, the electrodes of the actuators in adjacent rows have opposing polarities such that the actuators in adjacent rows have opposing current flow directions. Preferably the electrodes in each row are offset from its adjacent actuators in a direction transverse to the row such that the electrodes of every second actuator are collinear. In particularly preferred embodiments, the droplet ejectors are fabricated on an elongate wafer substrate extending parallel to the rows of the actuators, and power and data supplied along a long edge of the wafer substrate. In some embodiments, the printhead has a print engine controller (PEC) for sending print data to the array of nozzles; wherein, during use the print engine controller can selectively reduce the print resolution by apportioning print data for a single nozzle between at least two nozzles of the array. Preferably, the two nozzles are positioned in the array such that they are nearest neighbours in a direction transverse to the movement of the printhead relative to a print media substrate. In a particularly preferred form, the PEC shares the print data equally between the two nozzles in the array. Preferably, the two nozzles are spaced at less than 40 micron centers. In a particularly preferred form, the printhead is a pagewidth printhead and the two nozzles are spaced in a direction transverse to the media feed direction at less than 16 micron centers. Preferably, the adjacent nozzles are spaced in a direction transverse to the media feed direction at less than 8 micron centers. Preferably, the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction. In a farther preferred form, the nozzle pitch is greater than 3000 npi. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: FIG. 1A is a schematic representation of the linking printhead IC construction; FIG. 1B shows a partial plan view of the nozzle array on a printhead IC according to the present invention; FIG. 2 is a unit cell of the nozzle array; FIG. 3 shows the unit cell replication pattern that makes up the nozzle array; FIG. 4 is a schematic cross section through the CMOS layers and heater element of a nozzle; FIG. 5A schematically shows an electrode arrangement with opposing electrode polarities in adjacent actuator rows; FIG. 5B schematically shows an electrode arrangement with typical electrode polarities in adjacent actuator rows; FIG. 6 shows the electrode configuration of the printhead IC of FIG. 1 ; FIG. 7 shows a section of the power plane of the CMOS layers; FIG. 8 shows the pattern etched into the sacrificial scaffold layer for the roof/side wall layer. FIG. 9 shows the exterior surface of the roof layer after the nozzle apertures have been etched; FIG. 10 shows the ink supply flow to the nozzles; FIG. 11 shows the different inlets to the chambers in different rows; FIG. 12 shows the nozzle spacing for one color channel; FIG. 13 shows an enlarged view of the nozzle array with matching elliptical chamber and ejection aperture; FIG. 14 is a sketch of a photolithographic stepper; and, FIGS. 15A to 15C schematically illustrate the operation of a photolithographic stepper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The printhead IC (integrated circuit) shown in the accompanying drawings is fabricated using the same lithographic etching and deposition steps described in the U.S. Ser. No. 11/246,687 filed 11 Oct. 2005, the contents of which are incorporated herein by reference. The ordinary worker will understand that the printhead IC shown in the accompanying drawings have a chamber, nozzle and heater electrode configuration that requires the use of exposure masks that differ from those shown in U.S. Ser. No. 11/246,687 filed 11 Oct. 2005 Figures. However tire process steps of forming the suspended beam heater elements, chambers and ejection apertures remains the same. Likewise, the CMOS layers are formed in the same manner as that discussed U.S. Ser. No. 11/246,687 filed 11 Oct. 2005 with the exception of the drive FETs. The drive FETs need to be smaller because the higher density of the heater elements. Linking Printhead Integrated Circuits The Applicant has developed a range of printhead devices that use a series of printhead integrated circuits (IC's) that link together to form a pagewidth printhead. In this way, the printhead IC's can be assembled into printheads used in applications ranging from wide format printing to cameras and cellphones with inbuilt printers. The printhead IC's are mounted end-to-end on a support member to form a pagewidth printhead. The support member mounts the printhead IC's in the printer and also distributes ink to the individual IC's. An example of this type of printhead is described in U.S. Ser. No. 11/293,820, the disclosure of which is incorporated herein by cross reference. It will be appreciated that any reference to the term ‘ink’ is to be interpreted as any printing fluid unless it is clear from the context that it is only a colorant for imaging print media. The printhead IC's can equally eject invisible inks, adhesives, medicaments or other functionalized fluids. FIG. 1A shows a sketch of a pagewidth printhead 100 with the series of printhead IC's 92 mounted to a support member 94 . The angled sides 96 allow the nozzles from one of the IC's 92 overlap with those of an adjacent IC in the piper feed direction 8 . Overlapping the nozzles in each IC 92 provides continuous printing across the junction between two IC's. This avoids any ‘banding’ in the resulting print. Linking individual printhead IC's in this manner allows printheads of any desired length to be made by simply using different numbers of IC's. The end to end arrangement of the printhead IC's 92 requires the power and data to be supplied to bond pads 98 along the long sides of each printhead IC 92 . These connections, and the control of the linking IC's with a print engine controller (PEC), is described in detail in Ser. No. 11/544,764 filed 10 Oct. 2006. 3200 dpi Printhead Overview FIG. 1B shows a section of the nozzle array on the Applicants recently developed 3200 dpi printhead. The printhead has ‘true’ 3200 dpi resolution in that the nozzle pitch is 3200 npi rather than a printer with 3200 dpi addressable locations and a nozzle pitch less than 3200 npi. The section shown in FIG. 1B shows eight unit cells of the nozzle array with the roof layer removed. For the purposes of illustration, the ejection apertures 2 have been shown in outline. The ‘unit cell’ is the smallest repeating unit of the nozzle array and has two complete droplet ejectors and four halves of the droplet ejectors on either side of the complete ejectors. A single unit cell is shown in FIG. 2 . The nozzle rows extend transverse to the media feed direction 8 . The middle four rows of nozzles are one color channel 4 . Two rows extend either side of the ink supply channel 6 . Ink from the opposing side of the wafer flows to the supply channel 6 through the ink feed conduits 14 . The upper and lower ink supply channels 10 and 12 are separate color channels (although for greater color density they may print the same color ink—eg a CCMMY printhead). Rows 20 and 22 above the supply channel 6 are transversely offset with respect to the media feed direction 8 . Below the ink supply channel 6 , rows 24 and 26 are similarly offset along the width of the media. Furthermore, rows 20 and 22 , and rows 24 and 26 are mutually offset with respect to each other. Accordingly, the combined nozzle pitch of rows 20 to 26 transverse to the media feed direction 8 is one quarter the nozzle pitch of any of the individual rows. The nozzle pitch along each row is approximately 32 microns (nominally 31.75 microns) and therefore the combined nozzle pitch for all the rows in one color channel is approximately 8 microns (nominally 7.9375 microns). This equates to a nozzle pitch of 3200 npi and hence the printhead has ‘true’ 3200 dpi resolution. Unit Cell FIG. 2 is a single unit cell of the nozzle array. Each unit cell has the equivalent of four droplet ejectors (two complete droplet ejectors and four halves of the droplet ejectors on both sides of the complete ejectors). The droplet ejectors are the nozzle, the chamber, drive FET and drive circuitry for a single MEMS fluid ejection device. The ordinary worker will appreciate that the droplet ejectors are often simply referred to as nozzles for convenience but it is understood from the context of use whether this term is a reference to just the ejection aperture or the entire MEMS device. The top two nozzle rows 18 are fed from the ink feed conduits 14 via the top ink supply channel 10 . The bottom nozzle rows 16 are a different color channel fed from the supply channel 6 . Each nozzle has an associated chamber 28 and heater element 30 extending between electrodes 34 and 36 . The chambers 28 are elliptical and offset from each other so that their minor axes overlap transverse to the media feed direction. This configuration allows the chamber volume, nozzle area and heater size to be substantially the same as the 1600 dpi printheads shown in the above referenced U.S. Ser. No. 11/246,687 filed 11 Oct. 2005. Likewise the chamber walls 32 remain 4 microns thick and the area of the contacts 34 and 36 are still 10 microns by 10 microns. FIG. 3 shows the unit cell replication pattern that makes up the nozzle array. Each unit cell 38 is translated by its width x across the wafer. The adjacent rows are flipped to a mirror image and translated by half the width; 0.5x=y. As discussed above, this provides a combined nozzle pitch for the rows of one color channel ( 20 , 22 , 24 and 26 ) of 0.25x. In the embodiment shown, x=31.75 and y=7.9375. This provides a 3200 dpi resolution without reducing the size of the heaters, chambers or nozzles. Accordingly, when operating at 3200 dpi, the print density is higher than the 1600 dpi printhead of U.S. Ser. No. 11/246,687 filed 11 Oct. 2005, or the printer can operate at 1600 dpi to extend the life of the nozzles with a good print density. This feature of the printhead is discussed further below. Heater Contact Arrangement The heater elements 30 and respective contacts 34 and 36 are the same dimensions as the 1600 dpi printhead IC of U.S. Ser. No. 11/246,687 filed 11 Oct. 2005. However, as there is twice the number of contacts, there is twice the number of FET contacts (negative contacts) that punctuate the ‘power plane’ (the CMOS metal layer carrying the positive voltage). A high density of holes in the power plane creates high resistance through the thin pieces of metal between the holes. This resistance is detrimental to overall printhead efficiency and can reduce the drive pulse to some heaters relative to others. FIG. 4 is a schematic section view of the wafer, CMOS drive circuitry 56 and the heater. The drive circuitry 56 for each printhead IC is fabricated on the wafer substrate 48 in the form of several metal layers 40 , 42 , 44 and 45 separated by dielectric material 41 , 43 and 47 through which vias 46 establish the required inter layer connections. The drive circuitry 56 has a drive FET (field effect transistor) 58 for each actuator 30 . The source 54 of the FET 58 is connected to a power plane 40 (a metal layer connected to the position voltage of the power supply) and the drain 52 connects to a ground plane 42 (the metal layer at zero voltage or ground). Also connected to the ground plane 42 and the power plane 40 are the electrodes 34 and 36 or each of the actuators 30 . The power plane 40 is typically the uppermost metal layer and the ground plane 42 is the metal layer immediately beneath (separated by a dielectric layer 41 ). The actuators 30 , ink chambers 28 and nozzles 2 are fabricated on top of the power plane metal layer 40 . Holes 46 are etched through this layer so that the negative electrode 34 can connect to the ground plane and an ink passage 14 can extend from the rear of the wafer substrate 48 to the ink chambers 28 . As the nozzle density increases, so to does the density of these holes, or punctuations through the power plane. With a greater density of punctuations through the power plane, the gaps between the punctuations are reduced. The thin bridge of metal layer though these gaps is a point of relatively high electrical resistance. As the power plane is connected to a supply along one side of the printhead IC, the current to actuators on the non-supply side of the printhead IC may have had to pass through a series of these resistive gaps. The increased parasitic resistance to the non-supply side actuators will affect their drive current and ultimately the drop ejection characteristics from those nozzles. The printhead uses several measures to address this. Firstly, adjacent rows of actuators have opposite current flow directions. That is, the electrode polarity in one rows is switched in the adjacent row. For the purposes of this aspect of the printhead, two rows of nozzles adjacent the supply channel 6 should be considered as a single row as shown in FIG. 5A instead of staggered as shown in the previous figures. The two rows A and B extend longitudinally along the length of the printhead IC. All the negative electrodes 34 arc along the outer edges of the two adjacent rows A and B. The power is supplied from one side, say edge 62 , and so the current only passes through one line of thin, resistive metal sections 64 before it flows through the heater elements 30 in both rows. Accordingly, the current flow direction in row A is opposite to the current, flow direction in row B. The corresponding circuit diagram illustrates the benefit of this configuration. The power supply V+ drops because of the resistance R A of the thin sections between the negative electrodes 34 of row A. However, the positive electrodes 36 for all the heaters 30 are at the same voltage relative to ground (V A =V B ). The voltage drop across all heaters 30 (resistances R BA and R BB respectively) in both rows A and B is uniform. The resistance R B from the thin bridges 66 between the negative electrodes 34 of row B is eliminated from. The circuit for rows A and B. FIG. 5B shows the situation if the polarities of the electrodes in adjacent rows are not opposing. In this case, the line of resistive sections 66 in row B are in the circuit. The supply voltage V+ drops through the resistance R A to V A —the voltage of the positive electrodes 36 of row A. From there the voltage drops to ground through the resistance R BA of the row A heaters 30 . However, the voltage V B at the row B positive electrodes 36 drops from V A though R B front the thin section 66 between the row B negative electrodes 34 . Hence the voltage drop though the raw B heaters 30 is less than that of row A. This in turn changes the drive pulse and therefore the drop ejection characteristics. The second measure used to maintain the integrity of the power plane is staggering adjacent electrodes pairs in each row. Referring to FIG. 6 , the negative electrodes 34 are now staggered such that every second electrode is displaced transversely to the row. The adjacent row of heater contacts 34 and 36 are likewise staggered. This serves to further widen the gaps 64 and 66 between the holes through the power plane 40 . The wider gaps have less electrical resistance and the voltage drop to the heaters remote from the power supply side of the printhead IC is reduced. FIG. 7 shows a larger section of the power plane 40 . The electrodes 34 in staggered rows 41 and 44 correspond to the color channel feed by supply channel 6 . The staggered rows 42 and 43 relate to one half the nozzles for the color channels on either side—the color fed by supply channel 10 and the color channel fed by supply channel 12 . It will be appreciated that a five color channel printhead IC has nine rows of negative electrodes that can induce resistance for the heaters in the nozzles furthest from the power supply side. Widening the gaps between the negative electrodes greatly reduces the resistance they generate. This promotes more uniform drop ejection characteristics from the entire nozzle array. Efficient Fabrication The features described above increase the density of nozzles on the wafer. Each individual integrated circuit is about 22 mm long, less than 3 mm wide and can support more than 10000 nozzles. This represents a significant increase on the nozzle numbers (70,400 nozzles per IC) in the Applicants 1600 dpi printhead IC's (see for example U.S. Ser. No. 11/246,687 field 11 Oct. 2005). In fact, a true 3200 dpi printhead nozzle array fabricated to the dimensions shown in FIG. 12 , has 12,800 nozzles. The lithographic fabrication of this many nozzles (more than 10,000) is efficient because the entire nozzle array fits within the exposure area of the lithographic stepper or scanner used to expose the reticles (photomasks). A photolithographic stepper is sketched in FIG. 14 . A light source 102 emits parallel rays of a particular wavelength 104 through the reticle 106 that carries the pattern to be transferred to the integrated circuit 92 . The pattern is focused through a lens 108 to reduce the size of the features and projected onto a wafer stage 110 the carries the integrated circuits 92 (or ‘dies’ as they are also known). The area of the wafer stage 110 illuminated by the light 104 is called the exposure area 112 . Unfortunately, the exposure area 112 is limited in size to maintain the accuracy of the projected pattern—whole wafer discs can not be exposed simultaneously. The vast majority of photolithographic steppers have an exposure area 112 less than 30 mm by 30 mm. One major manufacturer. ASML of the Netherlands, makes steppers with an exposure area of 22 mm by 22 mm which is typical of the industry. The stepper exposes one die, or a part of a die, and then steps to another, or another part of the same die. Having as many nozzles as possible on a single monolithic substrate is advantageous for compact printhead design and minimizing the assembly of the IC's on a support in precise relation to one another. The invention configures the nozzle array so that more than 10,000 nozzles fit into the exposure area. In feet the entire integrated circuit can fit into the exposure area so that more than 14,000 nozzles are fabricated on a single monolithic substrate without having to step and realign for each pattern. The ordinary worker will appreciate that the same applies to fabrication of the nozzle array using a photolithographic scanner. The operation of a scanner is sketched in FIG. 15A to 15C . In a scanner, the light source 102 emits a narrower beam of light 104 that is still wide enough to illuminate the entire width of the reticle 106 . The narrow beam 104 is focused through a smaller lens 108 and projected onto part of the integrated circuit 92 mounted in the exposure area 112 . The reticle 106 and the wafer stage 110 are moved in opposing directions relative to each other so that the reticle's pattern is scanned across the entire exposure area 112 . Clearly, this type of photo-imaging device is also suited to efficient fabrication of printhead IC's with large numbers of nozzles. Flat Exterior Nozzle Surface As discussed above, the printhead IC is fabricated in accordance with the steps listed in cross referenced U.S. Ser. No. 11/246,687 filed 11 Oct. 2005. Only the exposure mask patterns have been changed to provide the different chamber and heater configurations. As described in U.S. Ser. No. 11/246,687 filed 11 Oct. 2005, the roof layer and the chamber walls are an integral structure—a single Plasma Enhanced Chemical Vapor Deposition (PECVD) of suitable roof and wall material. Suitable roof materials may be silicon nitride, silicon oxide, silicon oxynitride, aluminium nitride etc. The roof and walls are deposited over a scaffold layer of sacrificial photoresist to form an integral structure on the passivation layer of the CMOS. FIG. 8 shows the pattern etched into the sacrificial layer 72 . The pattern consists of the chamber walls 32 and columnar features 68 (discussed below) which are all of uniform thickness. In the embodiment shown the thickness of the walls and columns is 4 microns. These structures are relatively thin so when the deposited roof and wall material cools there is little if any depression in the exterior surface of the roof layer 70 (see FIG. 9 ). Thick features in the etch pattern will hold a relatively large volume of the roof/wall material. When the material cools and contracts, the exterior surface draws inwards to create a depression. These depressions leave the exterior surface uneven which can be detrimental to the printhead maintenance. If the printhead is wiped or blotted, paper dust and other contaminants can lodge in the depressions. As shown in FIG. 9 , the exterior surface of the roof layer 72 is flat and featureless except for the nozzles 2 . Dust and dried ink is more easily removed by wiping or blotting. Refill Ink Flow Referring to FIG. 10 , each ink inlet supplies four nozzles except at the longitudinal ends of the array where the inlets supply fewer nozzles. Redundant nozzle inlets 14 are an advantage during initial printing and in the event of air bubble obstruction. As shown by the flow lines 74 , the refill flow to the chambers 28 remote front the inlets 14 is longer than the refill flow to the chambers 28 immediately proximate the supply channel 6 . For uniform drop ejection characteristics, it is desirable to have the same ink refill time for each nozzle in the array. As shown in FIG. 11 , the inlets 76 to the proximate chambers are dimensioned differently to the inlets 78 to the remote chambers. Likewise the column features 68 are positioned to provide different levels of flow constriction for the proximate nozzle inlets 76 and the remote nozzle inlets 78 . The dimensions of the inlets and the position of the column can tune the fluidic drag such that the refill times of all the nozzles in the array are uniform. The columns can also be positioned to damp the pressure pulses generated by the vapor bubble in the chamber 28 . Damping pulses moving though the inlet prevents fluidic cross talk between nozzles. Furthermore, the gaps 80 and 82 between the columns 68 and the sides of the inlets 76 and 78 can be effective bubble traps for larger outgassing babbles entrained in the ink refill now. Extended Nozzle Life FIG. 12 shows a section of one color channel in the nozzle array with the dimensions necessary for 3200 dpi resolution. It will be appreciated that ‘true’ 3200 dpi is very high resolution—greater than photographic quality. This resolution is excessive for many print jobs. A resolution of 1600 dpi is usually more than adequate. In view of this, the printhead IC sacrifice resolution by sharing the print data between two adjacent nozzles. In this way the print data that would normally be sent to one nozzle in a 1600 dpi printhead is sent alternately to adjacent nozzles in a 3200 dpi printhead. This mode of operation more than doubles the life of the nozzles and it allows the printer to operate at much higher print speeds. In 3200 dpi mode, the printer prints at 60 ppm (full color A4) and in 1600 dpi mode, the speed approaches 120 ppm. An additional benefit of the 1600 dpi mode is the ability to use this printhead IC with print engine controllers (PEC) and flexible printed circuit boards (flex PCBs) that are configured for 1600 dpi resolution only. This makes the printhead IC retro-compatible with the Applicant's earlier PECs and PCBs. As shown in FIG. 12 , the nozzle 83 is transversely offset front the nozzle 84 by only 7.9375 microns. They are spaced further apart in absolute terms but displacement in the paper feed direction can be accounted for with the timing of nozzle firing sequence. As the 8 microns transverse shift between adjacent nozzles is small, it can be ignored for rendering purposes. However, the shift can be addressed by optimizing the dither matrix if desired. Bubble, Chamber and Nozzle Matching FIG. 13 is an enlarged view of the nozzle array. The ejection aperture 2 and the chamber walls 32 are both elliptical. Arranging the major axes parallel to the media feed direction allows the high nozzle pitch in the direction transverse to the feed direction while maintaining the necessary chamber volume. Furthermore, arranging the minor axes of the chambers so that they overlap in the transverse direction also improves the nozzle packing density. The heaters 30 are a suspended beam extending between their respective electrodes 34 and 36 . The elongate beam heater elements generate a bubble that is substantially elliptical (in a section parallel to the plane of the wafer). Matching the bubble 90 , chamber 28 and the ejection aperture 2 promotes energy efficient drop ejection. Low energy drop ejection is crucial for a ‘self cooling’ printhead. Conclusion The printhead IC shown in the drawings provides ‘true’ 3200 dpi resolution and the option of significantly higher print speeds at 1600 dpi. The print data sharing at lower resolutions prolongs nozzle life and offers compatibility with existing 1600 dpi print engine controllers and flex PCBs. The uniform thickness chamber wall pattern gives a flat exterior nozzle surface that is less prone to clogging. Also the actuator contact configuration and elongate nozzle structures provide a high nozzle pitch transverse to the media feed direction while keeping the nozzle array thin parallel to the media feed direction. The specific embodiments described are in all respects merely illustrative and in no way restrictive on the spirit and scope of the broad inventive concept.

An inkjet printhead with an array of nozzles for ejecting drops of printing fluid onto print media. The print media moves in a print direction relative to the printhead and the nozzles in the array are spaced apart from each other by less than 10 microns in the direction perpendicular to the print direction. With nozzles spaced less than 10 microns apart in the direction perpendicular to the print direction, the printhead has a very high ‘true’ print resolution—i.e. the high number of dots per inch is achieved by a high number of nozzles per inch.

FIELD OF THE INVENTION The present invention relates to multimedia communications, and, in particular, relates to a particular technique for handling multimedia calls with clients having legacy phones and services. BACKGROUND OF THE INVENTION The world of telecommunications is evolving at a rapid pace. Consumers are perceived to demand new features, especially in the area of multimedia services. Sharing files, video conferencing, sharing a virtual white board, and similar activities are helpful in the business context as geographically dispersed personnel try to coordinate efforts on projects. While the business world may be the driving force behind the need for such multimedia services, the residential consumer may also desire to take advantage of these services. A few approaches have been proposed to provide integrated multimedia services. The first approach is to replace the customer premises equipment and network equipment with equipment that supports this functionality seamlessly. This approach is less than optimal for a number of reasons. First, it forces a large cost on the network providers and the consumers who have to replace costly, functioning equipment that, in many cases, is still well within its nominal life expectancy. Second, the older equipment has evolved over time until approximately three hundred different services are offered on this legacy equipment. After transitioning to the newer equipment, there will be a lag between deployment and reintegration of these services as new software must be written to implement the services on the new equipment. Many consumers of these services would not be happy with the loss of these services in the interim. Other drawbacks such as determining a standard or protocol and retraining users in the new hardware and software are also present. A second approach has been proposed by the assignee of the present invention and embodied in U.S. patent application Ser. No. 09/960,554, filed Sep. 21, 2001, which is hereby incorporated by reference in its entirety. That application provides a way to integrate multimedia capabilities with circuit switched calls. In the circuit based domain, this solution is functional. However, there remains a need for integrating multimedia capabilities in packet switched calls while preserving presently deployed network hardware. SUMMARY OF THE INVENTION The present invention provides a solution in the packet domain for integrating voice calls with multimedia sessions as a blended call. A blended call is a call which blends voice and multimedia functions into a single communication session. In an exemplary embodiment, a multimedia server is associated with a telephony server. The multimedia server has software incorporated therein that manages blended calls, using the functions of the multimedia server where appropriate and the telephony server where appropriate. To the multimedia server, there is a single session, but the session may have a voice component and a multimedia component. This software is sometimes referred to herein as a blender. In an alternate embodiment, the blender may be a function of sequential logic devices or other hardware that performs the same functions. Specifically, the present invention takes an incoming call from a remote caller that is received at a telephony server and accesses a database to determine if the intended recipient of the phone call has blended capabilities. If the answer is negative, the call is handled according to conventional protocols. If the answer is affirmative, the intended recipient supports blended calling, then the telephony server directs the call to a multimedia server, and particularly to a multimedia server with blender software associated therewith. The blender software receives the call request and initiates a single session with two call components: 1) a voice call component and 2) a multimedia call component. The voice call component is handled through the telephony server, and the multimedia call component is handled through the multimedia server. As used herein, the multimedia component includes all the non-voice parts of the call. As part of the two call components, two signaling paths are routed to the blender software, which may integrate the signaling paths into a single signal path as part of the single session, which is used by the multimedia server to control the bearer paths associated with the call. Further, when passing the voice call component back to the telephony server, the blender may include an indication that the component is being passed from the blender and that the telephony server is not to redirect or “loop” the signal back to avoid infinite loops between the blender and the telephony server. The indication to prevent the redirection or looping back may be a “loopback signal” such as a flag, information in a header, or other signaling technique. Additionally, the indication may not be a signal per se, but could be a persistent attribute such as call delivery via a specific trunk on the telephony server reserved for signals that have been processed by the blender. As used herein, the terms “loopback signal” and “loopback indication” cover such signals and indications. It should be appreciated that a loopback signal falls within the definition of a loopback indication as used herein. An outgoing call from a user that has blended capabilities may be processed at the telephony server and a destination address extracted to verify that the user is making a call. The telephony server, upon reference to a database to determine that the caller in this instance has blended capabilities, refers the call to a blender function on the multimedia server. The blender then initiates two call components: 1) a voice call component and 2) a multimedia call component. The multimedia server may handle both components as a single session, or may redirect or loop the voice call component back to the telephony server with an indication that the voice call component has been redirected back from blender processing. As noted above, the indication may be a loopback signal or loopback indication. While many systems may be used, the present invention is well suited for use with a Session Initiation Protocol for Telephones (SIP-T) configuration as the information included in the SIP-T messages contains the information helpful in setting up and tearing down the parallel call components. In another aspect of the present invention, an Intelligent Network (IN) signal may be used to determine if a blended call is being handled. If the call is a blended call, then the call is referred to the blender. If the call is not blended, the telephony server handles the call as normal. This embodiment effectively integrates the circuit based system described in the previously incorporated '554 application with the packet based approach of the present invention. Those skilled in the art will appreciate the scope of the present invention and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the invention, and together with the description serve to explain the principles of the invention. FIG. 1 illustrates a communication environment according to one embodiment of the present invention; FIG. 2 illustrates the methodology of an exemplary embodiment of an incoming voice call used in the present invention; FIG. 3 illustrates the methodology of an exemplary embodiment of an incoming multimedia call used in the present invention; FIG. 4 illustrates the methodology of an exemplary embodiment of an outgoing voice call used in the present invention; and FIG. 5 illustrates the methodology of an exemplary embodiment of an outgoing multimedia call used in the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the invention and illustrate the best mode of practicing the invention. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the invention and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. The present invention is designed to prolong the viability of existing network devices by allowing existing customer premises equipment and existing network elements to be used to support multimedia capabilities. As used herein, a blended call is a call that supports voice and multimedia exchanges of information. To create the blended call, a telephony server or a multimedia server sends calls to blender software. The blender software initiates parallel voice and multimedia components with the customer premises equipment. The voice session may pass through the telephony server with an indication that blended processing has occurred. The blender further keeps control of the signaling paths of the parallel components so that the bearer path may be controlled to accommodate multimedia requests at any stage during the call. Because of the desire to be backwards compatible, the present invention may be used on any number of network systems using a number of different protocols. An exhaustive list of suitable networks and protocols is beyond the scope of the present discussion, but those of ordinary skill in the art will appreciate variations on the subject matter herein disclosed after a review of an exemplary embodiment, which is based on a session initiation protocol (SIP) environment. A communication environment 10 capable of carrying out the concepts of the present invention is illustrated in FIG. 1 . The communication environment 10 depicted includes a communication network 12 , which may preferably include a packet switched network with SIP enabled devices. Thus, the network may include any type of packet switched network having devices using SIP to facilitate communications between two or more devices, also referred to herein as a SIP enabled network. Two clients 14 , 16 are connected to the communication network 12 . Each client 14 , 16 may have customer premises equipment (CPE) 18 associated therewith, denoted 18 A for client 14 and 18 B for client 16 . Specifically, client 14 may have a telephone type device 20 and a computer type device 22 . Client 16 may have a telephone type device 24 and a computer type device 26 . In general, the telephone type devices 20 , 24 are directed to voice communications with limited data options such as displaying a number called, a calling number, time elapsed and other common telephony functions. In contrast, the computer type devices 22 , 26 may have a monitor, a keyboard, user input devices, and other conventional computer features such that a user may provide inputs and receive outputs and particularly generate and view multimedia content on the computer type device 22 , 26 . It is possible that a telephone type device 20 , 24 could be integrated with its corresponding computer type device 22 , 26 into a single piece of customer premises equipment 18 with the functionalities of both devices. Telephone type devices 20 , 24 and computer type devices 22 , 26 may contain data processing devices such as microprocessors which implement software that may be stored on any appropriate computer readable medium such as memory, floppy disks, and compact discs. Alternatively, the functionality of the present invention may be stored in sequential logic as is well understood. The telephone type devices 20 , 24 may, if desired, be “dumb” SIP terminals, H.323 terminals, or other devices delivering primarily voice based service. Each piece of customer premises equipment 18 may be a user agent within the SIP enabled network. As the telephone type devices 20 , 24 and the computer type devices 22 , 26 do not have a full range of features, they may be referred to as feature limited user agents. Clients 14 , 16 are connected to the communication network 12 by one or more connections 28 . These connections 28 may be wireless or wirebased. In the event that they are wirebased, copper line, fiber optic line, or other comparable communication medium may be used. It is preferred that the connection 28 be a wideband connection, suitable for exchanging large amounts of information quickly. Note further that while multiple connections are shown, a single connection may in fact provide all the communication links to the customer premises equipment 18 . At some point in the communication network 12 , the connection 28 from the telephone type device 20 , 24 terminates on a telephony server, such as telephony servers 30 , 32 . The telephony servers 30 , 32 may be the CS2000 or DMS100 sold by Nortel Networks Limited of 2351 Boulevard Alfred-Nobel, St. Laurent, Quebec, Canada, H4S 2A9. Other class five telecommunication switches or comparable devices including a PBX or a KEY system could also be used as needed or desired and may support both circuit switched voice calls and voice over packet calls. The telephony servers 30 , 32 may communicate with one another and other components in the communication network 12 via a Session Initiation Protocol for Telephones (SIP-T). SIP-T is fully compatible with other SIP enabled devices. Still other communication protocols could be used if needed or desired. Each telephony server 30 , 32 may be connected to or integrated with a database (DB) server 34 , 36 . The database servers 34 , 36 may track which clients support which services. For example, a client 14 may support blended services, call forwarding, and the like, each of which is noted in the database server 34 . The database server 34 may index the entries by a trunk line, a directory number, or other unique identifier as is well understood. Other components of the present invention are multimedia servers (MS) 38 , 40 which may be positioned throughout the communication network 12 as needed to provide the appropriate quality of service for the present invention. Multimedia servers 38 , 40 are sometimes referred to in the industry as media portals and may be the Interactive Multimedia Server (IMS) sold by Nortel Networks Limited. The IMS is based on JAVA technology and is a SIP enabled device capable of serving SIP clients by providing call conferencing, call transfers, call handling, web access, whiteboarding, video, unified messaging, distributed call centers with integrated web access and other multimedia services. Other media portals or multimedia servers may also be used if needed or desired. Operating off of the data processing devices of the multimedia servers 38 , 40 is software that embodies blenders 42 , 44 respectively. An exemplary blender 42 , 44 is further explicated in commonly owned U.S. patent application Ser. No. 10/028,510, filed 20 Dec. 2001, which is hereby incorporated by reference in its entirety. The '510 application refers to the blender as a combined user agent. The present invention builds on the functionality described in the '510 application by showing how the telephony server and the multimedia server interact in response to commands from the blender. As an alternative to software, the blenders 42 , 44 may be instructions embedded in sequential logic or other hardware as is well understood. The present invention takes incoming and outgoing calls associated with a client, such as client 14 , and routes the call to the blender 42 associated with the telephony server 30 . The routing to the blender 42 may be done by standard telephony interfaces such as an ISUP trunk, a Primary Rate Interface (PRI) link, a Public Telephone Service (PTS) trunk, or more preferably a SIP or SIP-T connection. The blender 42 then initiates two parallel components for the call. The first component is a voice component and the second component is a multimedia component. Each component may be established with the corresponding piece of customer premises equipment 18 A, and the signaling paths pass through and are controlled by the blender 42 . A more detailed exploration of this is presented below. It should be appreciated that the various components within the communication network 12 may communicate with one another even though specific connections are not illustrated. This reflects that in a packet network, the connections are frequently virtual and may change over time or between packets depending on load, router availability, and similar network traffic conditions. Further, the SIP enabled network may have gateways to the Public Switched Telephone Network (PSTN), the Public Land Mobile Network (PLMN), and the like. As the particular network and protocol are not central to the present invention, a further discussion of these well known elements is foregone. Also, the particular connections to the client 14 may be varied. For example, a single Digital Subscriber Line (DSL) into a location may serve both the telephone type device 20 and the computer type device 22 . Alternatively, the telephone type device 20 may be served by a phone line and the computer type device 22 served by a cable modem or the like as is well understood. Before turning to the details of the present invention, an overview of SIP may be helpful, as the following discussion is couched in terms of the commands used by SIP. The specification for SIP is provided in the Internet Engineering Task Force's Request for Comments (RFC) 3261: Session Initiation Protocol Internet Draft, which is hereby incorporated by reference in its entirety. A SIP endpoint is generally capable of running an application, which is generally referred to as a user agent (UA), and is capable of facilitating media sessions using SIP. User agents register their ability to establish sessions with a SIP proxy by sending “REGISTER” messages to the SIP proxy. The REGISTER message informs the SIP proxy of the SIP universal resource locator (URL) that identifies the user agent to the SIP network. The REGISTER message also contains information about how to reach specific user agents over the SIP network by providing the Internet Protocol (IP) address and port that the user agent will use for SIP sessions. A “SUBSCRIBE” message may be used to subscribe to an application or service provided by a SIP endpoint. Further, “NOTIFY” messages may be used to provide information between SIP endpoints in response to various actions or messages, including REGISTER and SUBSCRIBE messages. When a user agent wants to establish a session with another user agent, the user agent initiating the session will send an “INVITE” message to the SIP proxy and specify the targeted user agent in the “TO:” header of the INVITE message. Identification of the user agent takes the form of a SIP URL. In its simplest form, the URL is represented by a number of “<username>@<domain>”, such as “[email protected].” The SIP proxy will use the SIP URL in the TO: header of the message to determine if the targeted user agent is registered with the SIP proxy. Generally, the user name is unique within the name space of the specified domain. If the targeted user agent has registered with the SIP proxy, the SIP proxy will forward the INVITE message directly to the targeted user agent. The targeted user agent will respond with a “200 OK” message, and a session between the respective user agents will be established as per the message exchange required in the SIP specification. Media capabilities are passed between the two user agents of the respective endpoints as parameters embedded within the session setup messages, such as the INVITE, 200 OK, and acknowledgment (ACK) messages. The media capabilities are typically described using the Session Description Protocol (SDP). Once respective endpoints are in an active session with each other and have determined each other's capabilities, the specified media content may be exchanged during an appropriate media session. Against this protocol backdrop, FIG. 2 illustrates a flow chart of the methodology of an incoming call to a blended client 14 . In particular, a client 16 dials a number for the client 14 on the telephone type device 24 (block 100 ). The telephony server 32 receives the dialed number (block 102 ) as is conventional. The telephony server 32 references the database server 36 to learn that telephony server 30 serves the dialed number (block 104 ). The telephony server 32 contacts the telephony server 30 with the call request (block 106 ). So far, the call processing is performed according to any conventional protocol and over any conventional network hardware. When the telephony server 30 receives the call request, the telephony server 30 references the database server 34 about the number dialed (block 108 ) to determine if the number dialed supports blended services (block 110 ). If the answer to block 110 is “no”, blended services are not supported, the telephony server 30 rings the client 14 conventionally (block 112 ). If, however, the answer to block 110 is “yes”, the dialed number does support blended services, then the telephony server 30 passes the call request to the blender 42 in the multimedia server 38 (block 114 ). The blender 42 issues an INVITE message (hereinafter “invite”) to the multimedia server 38 (block 116 ). The multimedia server 38 performs call disposition handling including offering the call to client 14 (block 118 ). Call disposition handling may include for example a “find-me, follow-me” function, call blocking, routing to voice mail based on call screening criteria, updating a user's presence-state information, and the like. The multimedia server 38 sends an “invite” to the client 14 via the blender 42 (block 120 ). The blender 42 separates the “invite” into a call request and a multimedia request (block 122 ). The requests may be INVITE messages according to the SIP standard. The blender 42 sends the call request back to the telephony server 30 which rings the telephone type device 20 (block 124 ). The blender 42 may, as part of sending the call request back to the telephony server 30 , include indicia or otherwise provide an indication that designates that the call request is coming from the blender such that the telephony server 30 does not redirect or otherwise loop the call request back to the blender 42 as would be normal for an incoming call. These indicia may take any appropriate form such as a flag, information in the header, a persistent condition, or other technique, and prevent an infinite loop from forming between the telephony server 30 and the blender 42 . The blender 42 sends the multimedia request to the computer type device 22 (block 126 ). The multimedia server 38 maintains control over the signaling paths associated with the blended session. In an exemplary embodiment, the blender 42 merges the signaling paths of the voice component and the multimedia component into a single signaling path and passes the merged signaling path to the multimedia server 38 as a single session. By having access to the signaling path of the session, the multimedia server 38 may control the bearer paths of the components without having to parse the information in the bearer path. Note that because SIP is being used, the multimedia server 38 has access to the Uniform Resource Locators (URLs) of the endpoints of the call (the respective clients 14 , 16 ), the capabilities of the clients 14 , 16 , and other information relevant to the call disposition handling. Other protocols may provide the same information, but SIP is particularly well suited for this task. FIG. 3 illustrates an incoming multimedia call methodology. The client 16 desires to instant message (IM) the client 14 . To achieve this, the client 16 IM's the client 14 with computer type device 26 (block 150 ). The IM request may include an address for the client 14 , an indication that the client 16 supports blended capabilities and other SIP information. The multimedia server 40 receives the IM request (block 152 ) and references a database (not shown explicitly) to learn that multimedia server 38 serves the address (block 154 ). The multimedia server 40 contacts the multimedia server 38 with the IM request (block 156 ). The multimedia server 38 sends an “invite” to client 14 via the blender 42 (block 158 ). The blender 42 separates the “invite” into a call request and a multimedia request (block 160 ). The call request is passed to the telephony server 30 with indicia that the call request is coming from the blender 42 (block 162 ) to prevent the creation of an infinite loop. The telephony server 30 sends an “invite” to the telephone type device 20 (block 164 ). At this point the telephone type device 20 may not ring, but it may answer the “invite” to set up the signaling path associated with the provision of call services. The blender 42 also sends an “invite” to the computer type device 22 (block 166 ). The answers from the telephone type device 20 and the computer type device 22 arrive at the blender 42 (block 168 ), which merges them into a single signaling path and delivers the signaling path to the multimedia server 38 . The multimedia server 38 then manages the call (block 170 ) by maintaining control over the signaling path and allowing the bearer path to be routed through the communication network 12 as needed. If at any point one of the clients 14 , 16 wishes to establish a voice connection, the signaling path for the voice session is already in existence through the blender 42 and may be activated. Alternatively, the invitation for the voice component may only be generated upon request by the users. Thus, the IM session may continue as normal until a user decides to speak with the other party. Upon issuing the appropriate command to the computer type device 22 , the blender 42 receives the request to activate the voice component. FIG. 4 illustrates the methodology of an outgoing voice call from a client 14 . The client 14 dials a number with the telephone type device 20 (block 200 ). The telephony server 30 receives the dialed number (block 202 ). The destination address is extracted by the telephony server 30 (block 204 ) to determine that the client 14 is actually making a call rather than activating a call handling feature such as call forwarding, programming a speed call number, or similar features. The call can be a speed call activation, a normally dialed number, or other technique such that an indication is made that there is a call and not a call handling feature. The telephony server 30 references the database 34 (block 206 ) and determines if the client 14 supports blended services (block 208 ). If the answer to block 208 is “no”, the client 14 does not support blended services, the call is processed conventionally (block 210 ). If however, the answer to block 208 is “yes”, the client 14 does support blended services, the telephony server 30 passes the call to the blender 42 (block 212 ). The blender 42 sends an “invite” to the computer type device 22 (block 214 ). The computer type device 22 accepts (block 216 ). Note that a bearer path may not exist yet to the computer type device 22 , but the signaling path associated with the provision of the multimedia session may be created such that if the client 14 desires to begin using multimedia services, they are readily available. The blender 42 passes the combined signal to the multimedia server 38 (block 218 ). The multimedia server 38 performs call disposition handling and sends an “invite” to client 16 (block 220 ). The multimedia server 38 may route the voice portion of the call back through the telephony server 30 if needed or desired, or may handle that portion itself. Other arrangements could also be made. Note also that the invitation to the computer type device 22 may not be issued until a function is invoked that necessitates the provision of multimedia services. FIG. 5 illustrates an exemplary method of an outgoing multimedia call from the client 14 . The client 14 desires to instant message the client 16 and sends an IM to client 16 with the computer type device 22 (block 250 ). The multimedia server 38 receives the multimedia request (block 252 ). The multimedia server 38 may reference a database (not shown explicitly) to determine which multimedia server serves the destination address of the IM request (block 254 ). The multimedia server 38 sends an invitation to the client 14 via the blender 42 (block 256 ). Concurrently with the invitation to the client 14 , the multimedia server 38 sends an “invite” to the multimedia server 40 (block 258 ). The multimedia server 40 then invites the client 16 to join the call (block 260 ). The blender 42 is meanwhile separating the “invite” to the client 14 into a call request and a multimedia request (block 262 ). The blender 42 invites the telephone type device 20 and the computer type device 22 (block 264 ) to join the call. Note that the original request from the computer type device 22 may cause the multimedia request to subsume into the original request. Further, the “invite” to the telephone type device 20 may be routed through the telephony server 30 and have a loopback signal or a loopback indication that prevents the formation of an infinite loop between the telephony server 30 and the blender 42 . The blender 42 passes the combined signaling path from the telephone type device 20 and the computer type device 22 to the multimedia server 38 (block 266 ) and the multimedia server 38 connects the signal from the blender 42 with the signal from the multimedia server 40 and performs call disposition handling (block 268 ). Again, it is possible that the telephony server 30 may not pass the invitation to the telephone type device 20 until that function is invoked by the participants. As another embodiment, instead of relying on SIP for all of the trigger commands, the present invention may be integrated with an Intelligent Network (IN) such that for basic call disposition handling, the IN triggers and commands are used. For mid-call activation of multimedia features, the fact that the multimedia server 38 has access to the signaling path allows the multimedia server 38 to provide the requested multimedia services. For more information on the use of the IN as a trigger point, see the previously incorporated '554 application. Note that while the processes above have been described in a generally linear fashion, it is within the scope of the present invention to rearrange the order of some of the steps such that they occur concurrently or in different orders where needed or desired. Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present invention. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.

A communications system that supports multimedia components is easily adapted to existing network elements. Voice components arriving at or coming from a user having multimedia capabilities are referred from a telephony server serving the user to a multimedia server. A determination is made as to whether the other party supports multimedia capabilities. If that determination is negative, the component is passed back to the telephony server with an indication that the session is coming from the multimedia server to avoid an infinite loop. If the determination is positive, a parallel multimedia component is established between the parties while the multimedia server remains aware of the bearer path.

CROSS-REFERENCE TO RELATED APPLICATION This application is a construction-in-part of application Ser. No. 133,755 filed Mar. 25, 1980, now abandoned. The disclosure of that application is incorporated herein by cross-reference. BACKGROUND OF THE INVENTION Large caverns are solution-mined in salt formations and subsequently used for the storage of hydrocarbons such as petroleum and petroleum products. Caverns in salt domes, usually known as wells or jugs, are routinely used for storing high vapor pressure, low molecular weight hydrocarbons such as ethane, ethylene, propane, propylene, and butane. The hydrocarbon is stored on top of brine in the well. When the hydrocarbon is transferred to the cavern, brine is displaced to an open pit. Brine is subsequently pumped from the pit into the well to displace and thereby recover the hydrocarbon. Salt formations which are solution-mined to form caverns often contain large quantities of gases such as methane and ethane as well as carbon dioxide. When liberated by the dissolution of the salt, these gases dissolve in the brine. Further, when fresh waters from open reservoirs and streams are used to solution mine the salt, oxygen and nitrogen from the air dissolved in the fresh water are carried into the caverns and remain dissolved in the brine. Such contaminating gases (O 2 , CO 2 , CH 4 , C 2 H 6 , etc.) are many times more soluble in stored liquid hydrocarbons such as ethylene, propylene, propane, etc., at well storage conditions than in brine. Thus, with long exposure times, large quantities of the gases in the brine are transferred to the stored hydrocarbon. Often the quantity of gases transferred is sufficient to exceed specifications for contaminating gases in the stored hydrocarbon. Reprocessing of the stored hydrocarbon is sometimes required to reduce the contaminating gases below specified amounts. A process for removing contaminating gases from water in an underground cavern is disclosed in U.S. Pat. No. 3,289,416. The disclosed invention requires heating the water and stripping the heated water in a simple tower with a suitable stripping gas to remove the CO 2 and O 2 which normally would be liberated at that temperature and a portion of the remaining dissolved CO 2 and O 2 , depending upon the efficiency of the column. This process, however, is relatively inefficient compared to the present invention, as explained hereinafter. Other patents considered pertinent to the present invention include U.S. Pat. Nos. 3,083,537; 2,104,759; and 3,856,482. SUMMARY OF THE INVENTION The present invention pertains to a process for storing a liquefied gas such as a hydrocarbon over a liquid such as water or brine in an underground cavern such as a salt dome cavern. Before admitting the liquefied gas to the cavern, the liquid such as brine is treated to remove contaminating gases therefrom. The contaminating gas (e.g. O 2 , CO 2 , CH 4 , C 2 H 6 , etc.) preferably is removed by sparging (i.e., bubbling a gas through the liquid in the cavern). The sparging gas preferably is nitrogen although another gas such as methane (if it is a non-contaminant) may be utilized, or even some of the gas which is to be stored over the brine or other liquid. Nitrogen gas is preferred inasmuch as it is readily available, performs exceptionally well in removing most contaminating gases from the brine or other liquid and can be released safely to the atmosphere. Thus, as a nitrogen bubble passes through the brine, the contaminating gases pass from the brine into the nitrogen in the bubble in an attempt to establish equilibrium with respect to their partial pressures in the two phases. When a bubble of nitrogen leaves the brine at the top of the well and is recovereed or released (e.g. to the atmosphere), the contaminating gas is removed from the system. Accordingly, a principal improvement of the present invention is the utilization of a sparging technique to decontaminate a brine or other liquid in situ in an underground cavern. DESCRIPTION OF THE DRAWING FIG. 1 is a schematic depiction of the use of nitrogen to decontaminate brine in a salt cavern. DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows the use of nitrogen (or another gas such as methane) to decontaminate brine (or another liquid such as water) in a salt dome cavern (or other underground cavern). The nitrogen 1 is admitted (at a pressure of about 20 to 1000 psig and temperature of about 30° to 140° F.) through a sparger string 2 passing through a seal 3. Brine 4 is passed through a brine string 6 and a seal 7. Sparger string 2 extends downwardly into a salt dome cavern 8 having a brine level 9. Typically, the brine 14 (or other liquid) is at a temperature of 75° to 140° F. Sparger string 2 connects with sparger 10 close to the bottom of cavern 8 and releases bubbles 11 which pass upwardly in the brine, out of the cavern via casing 12 and then to atmosphere or recovery via conduit 13. Gas bubbles tend to spread and swirl and mix thoroughly with the brine in every part of the cavern. When brine is pumped out for degassing as is the case with the invention of U.S. Pat. No. 3,289,416 cited above, a thorough mixing action is not readily obtained, and the brine in the remote areas of the cavern can only be thoroughly reached after extensive pumping. About 75% of the contaminating gases are removed from a salt dome is one week by the present invention. By comparison, approximately three months of pumping at normal rates as practiced in the art are required to remove 75% of the gases by a process such as that in U.S. Pat. No. 3,289,416. The dispersing of gas in the liquid brine is preferably accomplished by sparging through simple bubblers such as an open-end standpipe, a horizontal perforated pipe, or a perforated plate at the bottom of the cavern. Although the size of the bubbles will be a function of the discharge pressure and of the diameter of the orifice through which the gas is introduced at low rates, at ordinary gassing rates relatively large bubbles will be produced regardless of the size of the orifice. Perforated pipes or plate spargers usually have orifices 1/8 to 1/2-inch in diameter. A perforated pipe sparger is designed so that the pressure drop across the individual orifices is large compared with the pressure drop down the length of the pipe; otherwise the orifices most remote from the gas supply may not function. Porous septa in the form of plates, tubes, discs, or other shapes may be utilized instead of simple bubblers and are made by bonding together carefully sized particles of carbon, ceramics or metal. The resulting septa may be used as spargers to produce much smaller and more efficient bubbles than will result from a simple bubbler. The size of the bubbles formed is proportional not only to the pore diameter but also to the pressure drop across the septum. At high gas rates, coalescence occurs on the surface of the septum, and poor gas dispersion results. EXAMPLE After completing the solution mining of a well in a salt formation, the well is full of fresh brine which contains large quantities of oxygen, carbon dioxide, methane, ethane, etc. The quantities of these gases are reduced as follows: (1) a pipe equipped with a folding sparger or a nozzle is lowered through a brine string to near the bottom of the well (for most applications this can be a nominal 2-inch pipe); (2) after passing from the brine string near the bottom of the cavern, the sparger arms are released to assume a horizontal position; (3) pressurized nitrogen is forced into the annulus (brine string-casing) to displace about 500 barrels of brine from the annulus and the cavern; (4) preferably, pressure on the nitrogen in the dome cavern above brine level 9 is reduced, more preferably to a pressure no lower than atmospheric pressure; (5) cryogenic nitrogen is heated and forced to the bottom of the cavern utilizing the sparger piping; (6) the nitrogen, as bubbles, passes up through the brine in the well and out of the well through the conduit normally used to transfer a liquid hydrocarbon (for storage) to and from the cavern; (7) upon passing through the brine, contaminating gases, by diffusion, are transferred from the brine to the nitrogen in the bubble; (8) upon reaching the atmosphere, nitrogen containing the contaminants is released or processed to remove the contaminating gas; (9) nitrogen is added until an analysis of the exiting nitrogen approaches the desired content of contaminated gases; (10) the pipe and sparger are removed from the brine string; (11) brine is added through the brine string to displace the nitrogen from the top of the cavern and tubing.

Liquid hydrocarbons are stored in salt dome caverns containing brine after first stripping the brine of contaminating gases such as oxygen and carbon dioxide by sparging a decontaminating gas such as nitrogen into the brine and removing the nitrogen and the contaminating gases from the salt dome cavern.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 11/777,845, filed Jul. 13, 2007, now U.S. Pat. No. 8,085,382, which claims priority under 35 U.S.C. §119(e)(1) to U.S. provisional patent application Ser. No. 60/807,367, filed Jul. 14, 2006, and U.S. Provisional patent application Ser. No. 60/888,647, filed Feb. 7, 2007. U.S. application Ser. No. 11/777,845 also claims priority under 35 U.S.C. §119 to German patent application serial No. 10 2006 032 810.8, filed Jul. 14, 2006. The contents of these applications are hereby incorporated by reference in their entirety. FIELD The disclosure relates to optics, such as, for example, microlithographic projection exposure apparatus illumination optics, as well as related systems, methods, components and devices. BACKGROUND Typically, a microlithographic projection exposure apparatus includes an illumination system and a projection objective. SUMMARY The disclosure relates to optics, such as, for example, microlithographic projection exposure apparatus illumination optics, as well as related systems, methods, components and devices. In one aspect, the disclosure features a microlithographic projection exposure apparatus illumination optical system. The illumination optical system has an optical path, an object plane and a pupil plane. The illumination optical system is configured so that, during use when light passes through the illumination optical system along the optical path, the illumination optical system illuminates a field of the object plane with the light. The illumination optical system includes an optical module that is configured so that during use the first optical module sets a first illumination setting in the pupil plane of the illumination optical system. The illumination optical system also includes an additional optical module that is configured so that during use the second optical module sets a second illumination setting in the pupil plane of the illumination optical system. In addition, the illumination optical system includes at least one decoupling element in the optical path upstream of the two optical modules. The decoupling element is configured so that during use the decoupling element provides light to at least one of the two optical modules. The illumination optical system further includes at least one coupling element in the optical path downstream from the two optical modules. The at least one coupling element is configured so that during use the at least one coupling element provides the light which has passed through at least one of the two optical modules to the illumination field. In another aspect, the disclosure features a microlithographic projection exposure apparatus that includes a projection objective and the illumination optical system described in the preceding paragraph. In a further aspect, the disclosure features a method that includes using the illumination system described in the preceding two paragraphs to make a microstructured component. In an additional aspect, the disclosure features a system that includes a first optical module configured to be used in addition to a second optical module of illumination optics in a microlithographic projection exposure apparatus so that during use, when incorporated into the microlithographic projection exposure apparatus, the first and second optical module provide first and second illumination settings, respectively, in a pupil plane of the illumination optics. The system also includes at least one decoupling element configured to be incorporated into the illumination optics so that during use the at least one decoupling element is located in the optical path upstream from the first and second optical modules so that the at least one decoupling element provides light to at least one of the first and second optical modules. The system further includes at least one coupling element configured to be incorporated into the illumination optics so that during use the coupling element is located in the optical path downstream from the first and second optical modules so that it provides light from at least one of the first and second optical modules to the illumination field. In one aspect, the disclosure features a a microlithographic projection exposure apparatus that has a pupil plane. The microlithographic projection exposure apparatus includes a device configured so that, during use when light passes through the microlithographic projection exposure apparatus, the device alters an illumination setting in the pupil plane within a time period of 10 milliseconds or less. In another aspect, the disclosure features a microlithographic projection exposure apparatus that has a pupil plane and that is configured to image an object into an image plane using multiple, nearly periodic pulses of light. The microlithographic projection exposure apparatus includes a device configured so that during use the device changes an illumination setting in the pupil plane from a first illumination setting to a second illumination setting. In a further aspect, the disclosure features a system that includes a microlithographic projection exposure apparatus configured to image an object into an image plane using multiple, nearly periodic pulses of light. The microlithographic projection exposure apparatus includes a first optical element and a second optical element. The microlithographic projection exposure apparatus also includes a device configured so that during use the device alters the number of pulses between the first and second optical elements. In an additional aspect, the disclosure features a microlithographic projection exposure apparatus configured to image an object into an image plane using multiple, nearly periodic pulses of light having an average pulse duration. The microlithographic projection exposure apparatus includes a first optical element and a second optical element. The microlithographic projection exposure apparatus also includes a device configured so that during use the device alters the average pulse duration between the first and second optical elements. Embodiments can optionally provide one or more of the following advantages. In some embodiments, the systems can allow for relatively fast changes in optical settings (e.g., illumination settings) during use. In some instances, fast changes of illumination settings can be desirable for multiple exposure in order to illuminate the mask briefly at two different illumination settings. In certain embodiments, the systems can allow for relatively fast changes in optical settings (e.g., illumination settings) during use with relatively little or no movement of optical components and/or with relatively little or no light loss. In some embodiments, such advantages can be provided, for example, by including in the system at least two optical modules that are adjusted (e.g., preadjusted) to produce specific illumination settings (e.g., polarization settings) such that it is possible to switch between the optical modules as appropriate. Optionally, switching between optical modules can be accomplished mechanically, such as, for example, by temporarily introducing a mirror into the illumination light path. Alternatively or additionally, switching between optical modules can be accomplished by modifying a characteristic of the illumination light. Under some circumstances, this can allow relatively substantially different illumination settings to be accessible with relatively little switching effort. Optionally, switching can be performed between more than two optical modules (e.g., by cascaded decoupling elements and coupling elements), which can, for example, allow for switching between more than two different illumination settings (e.g., more than two different polarization states). In some embodiments, the change in light characteristic (e.g., polarization state) can take place in one second or less (e.g., one microsecond or less, 100 ns or less, 10 ns or less). In some embodiments, use of polarization-selective beam splitter can result in an illumination light beam with a relatively large cross-section which can advantageously result in a relatively low-energy and/or relatively low-intensity load on the beam splitter. In certain embodiments, depending on the illumination light wavelength used, a polarization cube or a beam splitter cube used in a variation can be made of CaF 2 or of quartz. Optionally, use can also be made of a, for example, optically coated beam splitter plate which lets through light having a first polarization direction and reflects light having a second polarization direction. Use of a Pockels cell can provide good switching between polarization states. Optionally, a Kerr cell which is suitable for changing the beam geometry can also be used. Also optionally, an acousto-optic modulator can be used as the light-characteristic changer in order to change the beam direction (the beam direction being modified by Bragg reflection). In some embodiments, a light-characteristic changer can be particularly well suited for obtaining a light load which is distributed over the optical components and well adapted to the time characteristic of light emission of commonly used light sources. In certain embodiments, a polarization changer can be an example of a light-characteristic changer where the light characteristic is changed by mechanically switching an optical component. The optical component can be switched so that, before and after switchover, the illumination light passes through the same optically active surface of the optical component. This is the case, for example, when a single λ/2 plate is used as a polarization changer. With other embodiments of the light-characteristic changer, various optically active regions of the optical component are used by this mechanical switching. The control expense for such a light-characteristic changer can be relatively low. In some embodiments, use of a second polarization optical component can create the possibility of using a polarization optical beam splitter to extract the illumination light. The first polarization optical component of the polarization changer can be a λ/2 plate having, in its operating position, an optical axis which is oriented differently compared to the second polarization optical component. The first polarization optical component can be a free passage through the polarization changer. In certain embodiments, changeover between the two optical modules can be obtained by temporarily inserting a mirror into the ray path of the illumination light. This variation requires relatively inexpensive control. Examples of decoupling elements are known, for example, from metrology and optical scanner technology. In some embodiments, a decoupling element can be relatively light weight. In certain embodiments, the first illumination setting and the second illumination setting generally differ. However, in some embodiments, the second illumination setting may also be exactly the same as, or similar within predetermined tolerance limits to, the first illumination setting, so the first illumination setting does not significantly differ from the second illumination setting in any light characteristic. In such cases, the change between the illumination settings can still lead to a reduction in the optical load on the components of the first and the second optical module, as merely a respective portion of the overall illumination light acts on these optical modules. Illumination settings are also different if they differ exclusively in the polarization of the illumination light fed to the object or illumination field. Such a difference in polarization may be a difference in the type of polarization of the light passing through a local point in a pupil of the illumination optics. The pupil is in this case the region through which illumination light passes of a pupil plane which is, in turn, optically conjugate with a pupil plane of an objective, in particular a projection objective, downstream from the illumination optics. Alternatively or additionally, a difference in polarization may also be a difference in the spatial distribution of the orientation of the type of polarization relative to the pupil coordinate system beyond the various local points of the pupil. The term “type of polarization” or “polarization state” refers in the present document to linearly and/or circularly polarized light and to any form of combinations thereof such as, for example, elliptically, tangentially and/or radially polarized light. It is, for example, possible in a first illumination setting to irradiate the entire object field with a first illumination light linear polarization state which is constant over the pupil. A second illumination setting can use light having polarization rotated for this purpose through a constant angle, for example through 90°, with respect to an axis of rotation. The polarization distribution does not in this case vary on rotation about the axis of rotation through the aforementioned constant angle. Alternatively, it is possible in a first illumination setting to illuminate the pupil with a first spatial polarization distribution, for example with the same polarization over the entire pupil and in a second illumination setting to illuminate portions of the pupil with a first polarization direction of the illumination light and other portions of the pupil with a further polarization direction of the illumination light. In this case, not only the polarization direction but also the polarization distribution in the pupil is varied. Under the terms of the present application, illumination settings are different if their intensity distribution as a scalar variable and/or their polarization distribution as a vectorial variable differs over the pupil. The differing polarization states may be described as vectorial variables in the pupil based on vectorial E-field vectors of the illumination light. The pupil may in this case also have a non-planar (a curved surface). The intensity distribution is then described as a scalar variable and the polarization distribution is then described as a vectorial variable over this curved surface. In some embodiments, the illumination settings may differ merely in terms of the polarization state, i.e. for example in the type of polarization (linear, circular) and/or in the polarization direction and/or in the spatial polarization distribution. This can allow the polarization state to be adapted to changing imaging features, especially features resulting from the geometry of the structures to be imaged. In certain embodiments, an optical delay can allow defined time synchronization of the illumination light guided through the first optical module relative to the illumination light guided through the second optical module in the light path after the coupling element. This can be used to homogenize in time a dose of light onto the optical components from the coupling element in order thus to reduce, especially in the case of pulsed light sources, the deposition of energy per pulse in the optical components. This can apply especially to the optical components of the projection exposure apparatus arranged after the coupling element in the direction of the illumination or projection beam such as, for example, a condenser, a REMA (reticle/masking) objective, a reticle or a mask, optical components of a projection objective, immersion layers, the photoresist, the wafer and the wafer stage. The optical delay component may be an optical delay line arranged in the light path of the first optical module or in the light path of the second optical module. The optical delay can be adjustable via the optical delay component, and this can be achieved, for example, via a linear sliding table movable along a path over which the illumination light can be guided several times and a mirror, in particular a retroreflecting mirror, rigidly connected to the linear sliding table. Alternatively, and especially for setting relatively short delay paths, the optical delay component may be configured as an optically transparent and optically denser medium having a predetermined optical path. Use may also be made of a combination of an optical delay component wherein the optical delay is based on enlargement of the pure path and an optical delay component wherein the optical delay is based on a light path in an optically denser medium. In some embodiments, the illumination optics can have a relatively small peak load on the reticle and/or on optical components downstream from the decoupling beam splitter. In some embodiments, by changing the light characteristic during the illumination light pulse, this pulse can be split into two light pulse parts which are then shaped into different illumination settings. This can advantageously reduce the illumination light load on the components, in particular the local load on the components. By changing the light characteristic during the illumination light pulse, if a laser is chosen as the light pulse source, it is possible to work with half the laser repetition rate, twice the pulse energy and double the pulse duration. The single pulse energy is in this case the integral of the power of the individual pulse over the pulse duration thereof. In some instances, such lasers can be relatively easily integrated in a microlithographic projection exposure apparatus. In certain embodiments, the optical modules can be subjected to a relatively low mean light output to which the optical modules are subjected because not all light pulses from the light source are conducted through the same optical module. Assuming appropriate synchronization, a decoupling element can be used instead of the light-characteristic changer. In such instances, the decoupling element can let through every second light pulse, for example, and the light pulses in between are reflected by the mirror elements of the decoupling element to the other optical module. The light-characteristic changer may, for example, be configured in such a way that the light characteristic changes between two successive light pulses. In some embodiments, illumination light which is generated by the at least two light sources can be coupled into an illumination light beam by a coupling optical device and this light beam illuminates the illumination field. A beam splitter of the same type as the coupling or decoupling beam splitter can be used to obtain coupling; this is, however, not compulsory. Alternatively, it is possible, for example, to merge at least two illumination light beams from the light sources via coupling mirrors or coupling lenses. In certain embodiments, the illumination system can be relatively compact. In certain embodiments, a control system can allow proportional adjustment of illumination of the illumination field with various preset illumination settings. These components can be produced by time-proportional illumination, i.e. by sequential illumination initially with a first and then with at least one other illumination setting or by intensity-proportional illumination, i.e. parallel illumination of the illumination field with a plurality of illumination settings with a preset intensity distribution. The main control system can also be connected to the coupling element by signals for control purposes if this is necessary in order to obtain changeover between optical modules. In some embodiments, the control system can acquire information concerning the relevant illumination setting via its signal links to the components of the illumination system, can specify specific preset lighting settings by acting on the adjustment of the optical modules and make additional adaptations, for example via the reticle masking system or scan speeds. The systems can be used, for example, in methods to manufacture components. In some embodiments, the optics can be in the form of a supplementary module for a microlithographic projection exposure apparatus. The supplementary module can, for example, be retrofitted to an existing illumination optics and an existing illumination system. This can, for example, allow the optics described herein to be used in pre-existing systems. This can, for example, reduce the cost and/or complexity associated with using the optics described herein. In certain embodiments, the individual components of the supplementary module, can be designed and developed as already described above in relation to the illumination optics according to the disclosure and the illumination system according to the disclosure. The further illumination setting provided by the supplementary module may differ from the illumination setting of the first optical module. In some applications, the further illumination setting can, in this case too, correspond within predetermined tolerance limits in all light characteristics to the illumination setting of the first optical module. A number of references are incorporated herein by reference. In the event of an inconsistency between the explicit disclosure of the present application and the disclosure in the references, the present application will control. Embodiments of the disclosure are described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of an embodiment of a microlithographic projection exposure apparatus. FIGS. 2 to 4 are schematic representations of two successive light pulses from a light source of a projection exposure apparatus. FIG. 5 is a schematic representation of an embodiment of a microlithographic projection exposure apparatus. FIGS. 6 to 9 are schematic representations of two successive light pulses from a light source of a projection exposure apparatus. FIGS. 10 and 11 are schematic representations of embodiments of a microlithographic projection exposure apparatus FIGS. 12 and 13 are schematic representations of embodiments of microlithographic projection exposure apparatuses. FIG. 14 is a schematic representation of an embodiment of a decoupling element and an embodiment of a coupling element. FIG. 15 is a schematic representation of an embodiment of a decoupling element and an embodiment of a coupling element. FIG. 16 is a schematic representation of an embodiment of a polarization changer. FIG. 17 is a schematic representation of an embodiment of a microlithographic projection exposure apparatus. FIGS. 18 and 19 are schematic representations of embodiments of illumination settings. FIGS. 20 and 21 are schematic representations of embodiments of mask structures. FIGS. 22 and 23 are schematic representations of embodiments of illumination settings. FIGS. 24 and 25 are schematic representations of embodiments of mask structures. FIGS. 26 and 27 are schematic representations of embodiments of illumination settings. FIGS. 28 and 29 show the two masks which are successively to be imaged onto the same wafer to be illuminated by double exposure with the illumination settings in FIGS. 26 and 27 , respectively. DETAILED DESCRIPTION FIG. 1 shows a microlithographic projection exposure apparatus 1 which can be used, for example, in the fabrication of semiconductor components and other finely structured components and which uses light in the vacuum ultraviolet range (VUV) to achieve resolutions of fractions of a micrometer. A light source 2 is (e.g., an ArF excimer laser with a working wavelength of 193 nm) produces a linearly polarized light beam 3 which is coaxially aligned with an optical axis 4 of an illumination system 5 of the projection exposure apparatus 1 . Other UV light sources (e.g., a F 2 laser with a working wavelength of 157 nm, an ArF laser with a working wavelength of 248 nm, a mercury vapour lamp with a working wavelength of 368 nm or 436 nm, light sources with wavelengths below 157 nm) can optionally be used as the light source 2 . Light exiting from the light source 2 is initially polarized perpendicularly to the plane of projection in FIG. 1 (s-polarization). This is indicated in FIG. 1 by the individual dots 6 on the light beam 3 . This linearly polarized light from the light source 1 first enters a beam expander 7 which can be formed, for example, as a mirror arrangement (such as described, for example, in DE 41 24 311, which is hereby incorporated by reference) and is used to reduce the coherence and increase the cross-section of the beam. After the beam expander 7 , the light beam 3 passes through a Pockels cell 8 which is an example of a light-characteristic changer. In general, as long as no voltage is applied to the Pockels cell 8 , the light beam 3 is still s-polarized as it leaves the Pockels cell 8 . The light beam 3 then passes through a decoupling beam splitter 9 which is an example of a decoupling element and is formed as a polarization cube made of CaF 2 or quartz. The decoupling beam splitter 9 lets the s-polarized light beam 3 through in the direction of the optical axis 4 and the beam passes through a first diffractive optical element (DOE) 10 . The first DOE 10 is used as a beam-shaping element and is located in an entry plane of a first lens group 11 positioned in the ray path downstream therefrom. The first lens group 11 includes a zoom system 11 a and a subsequent axicon setup 11 b . The zoom system 11 a is doubly telecentric and designed as a scalar zoom so that optical imaging with preset magnification is achieved between one entry plane and one exit plane of the zoom system 11 a . The zoom system 11 a can also have a focal-length zoom function so that triple Fourier transformation, for example, is performed between the entry plane and the exit plane of the zoom system 11 a . The illumination light distribution set after the zoom system 11 a is subjected to radial redistribution by the axicon elements of the axicon setup which can be displaced axially towards each other provided that a finite distance is set between the opposite-facing conical axicon surfaces of the axicon elements. If this gap is reduced to zero, the axicon setup 11 b basically acts as a plane-parallel plate and has practically no influence on the local distribution of illumination created by the zoom system 11 a . The axial clearance between the optical components of the zoom system 11 a and the axicon setup 11 b can be adjusted by actuators. The first lens group 11 is part of a pupil forming element which is used to set a defined local two-dimensional illumination intensity distribution for illumination light from the light source 2 in a pupil forming plane 12 of the illumination system 5 located downstream of lens group 11 (the illumination pupil or illumination setting). The pupil forming plane 12 which is a pupil plane of the illumination system 5 coincides with the exit plane of the first lens group 11 . A further optical raster element 13 is located in the immediate vicinity of the exit plane 12 . A coupling optic 14 located downstream therefrom transfers the illumination light to an intermediate field plane 15 in which a reticle masking system (REMA) 16 , which is used as an adjustable field stop, is located. The optical raster element 13 has a two-dimensional arrangement of diffractive or refractive optical elements and has several functions. On the one hand, incoming illumination light is shaped by the optical raster element 13 so that, after passing through subsequent coupling optic 14 in the region of the field plane 15 , it illuminates a rectangular shaped illumination field. The optical raster element 13 with a rectangular radiation pattern is also referred to as a field defining element (FDE) and generates the main component of the etendue and adapts it to the desired field size and field shape in the field plane 15 which is conjugate with a mask plane 17 . The optical raster element 13 can be designed as a prism array in which individual prisms arranged in a two-dimensional field introduce locally determined specific angles in order to illuminate the field plane 15 as required. The Fourier transformation performed by coupling optic 14 that each specific angle at the exit of the optical raster element 13 corresponds to a location in the field plane 15 whereas the location of the optical raster element 13 (its position in relation to the optical axis 4 , determines the illumination angle in the field plane 15 ). The beams emerging from the individual optical elements of the optical raster element 13 are superimposed in the field plane 15 . It is also possible to construct FDE 13 as a multistage honeycomb condenser with microcylinder lenses and diffusing screens. By constructing FDE 13 and its individual optical elements appropriately, it is possible to ensure that the rectangular field in the field plane 15 is substantially homogeneously illuminated. FDE 13 is thus also used as a field shaping and homogenising element for homogenising the field illumination so that a separate light-mixing element, for instance an integrator rod acting through multiple internal reflection or a honeycomb condenser, can be dispensed with. This can make the optical setup in this region especially axially compact. A downstream imaging objective 18 , which is also referred to as a REMA objective, images the intermediate field plane 15 with the REMA 16 onto a reticle or its surface 19 in the mask plane 17 on a scale which can be, for example, from 2:1 to 1:5 and, in the embodiment shown in FIG. 1 , is approximately 1:1. Imaging takes place without an intermediate image so that there is precisely one pupil plane 21 between the intermediate field plane 15 , which corresponds to an object plane of imaging objective 18 and an image plane of imaging objective 18 which coincides with the mask plane 17 and corresponds to the exit plane of the illumination system and, at the same time, an object plane of downstream projection objective 20 . The latter is a Fourier transformed plane relative to the exit plane 17 of the illumination system 5 . A deflection mirror 22 , tilted at 45° with respect to the optical axis 4 and positioned between the pupil plane 21 and the mask plane 17 , makes it possible to install a relatively large illumination system 5 , which is several meters long, horizontally and, at the same time, keep the reticle 19 horizontal. Those optical components which guide illumination light from the light source 2 and, from it, form the illumination light which is directed at the reticle 19 are part of the illumination system 5 of the projection exposure apparatus. Downstream from the illumination system 5 there is a device 23 for holding and manipulating the reticle 19 arranged so that a pattern on the reticle falls in object plane 17 of the projection objective 20 and, in this plane, can be moved with the aid of a scan drive for scan operation in a scan direction which is perpendicular to the optical axis 4 . The projection objective 20 is used as a reduction objective and forms an image of the reticle 19 on a reduced scale, for example on a 1:4 or 1:5 scale, on the wafer 24 which is coated with a photoresistive layer or photoresist layer, the light-sensitive surface of which lies in image plane 25 of the projection objective 20 . Refractive, catadioptric or catoptric projection objectives are possible. Other reduction scales, for instance greater minification, up to 1:20 or 1:200 are possible. The semiconductor wafer 24 which is to be exposed is secured by the device 26 configured to hold and/or manipulate it which includes a scanner drive in order to move the wafer 24 , in synchronism with the reticle 19 , perpendicularly to the optical axis 4 . These movements can be parallel to each other or anti-parallel, depending on the design of the projection objective 20 . The device 26 , which is also referred to as a wafer stage, and the device 23 , which is also referred to as a reticle stage, are component parts of a scanner which is controlled via a scan controller. The pupil forming plane 12 is located on or close to a position which is optically conjugate with next downstream pupil plane 21 and with image-side pupil plane of the projection objective 20 . This way, the spatial and local light distribution in the pupil plane 27 of the projection objective 20 can be determined by the spatial light distribution and local distribution in the pupil forming plane 12 of the illumination system 5 . Between each of the pupil surfaces 12 , 21 and 27 , there are field surfaces in the optical ray path which are Fourier-transformed surfaces relative to the relevant pupil surfaces. This can allow for a defined local distribution of illumination intensity in the pupil forming plane 12 can result in a specific angular distribution of the illumination light in the region of the downstream field plane 15 which, in turn, can correspond to specific angular distribution of the illumination light which falls onto the reticle 19 . Together with the first DOE 10 , the first lens group 11 forms a first optical component 28 configured to set a first illumination setting in the illumination pupil 12 . In some embodiments, the illumination system 5 can allow for relatively fast modification of the illumination pupil 12 during an illumination process (e.g., for an individual reticle 19 ). This can make double exposure or other multiple exposure possible at short time intervals. A second optical module 29 , which is located in the decoupling path 29 a of the decoupling beam splitter 9 , can be used for fast modification of the illumination setting in the pupil forming plane 12 . The second optical module 29 includes the second DOE 30 and a second lens group 31 which is, in turn, divided up into a zoom system 31 a and the axicon setup 31 b . The two optical modules 28 , 29 are of similar construction. The optical effect and the layout of the individual optical components of the zoom system 31 a , the axicon setup 31 b and of second DOE 30 are, however, different from the first optical module 28 so that illumination light from the light source 2 which passes through the second optical module 29 is influenced so that a second illumination setting which differs from the first illumination setting created by the first optical module 28 is produced in the pupil forming plane 12 . Decoupling path 29 a is indicated in FIG. 1 by the dashed line. In the decoupling path 29 a , the illumination light is guided in the parallel polarization direction (p-polarization) relative to the plane of projection in FIG. 1 which is indicated in FIG. 1 by double arrows 32 which are perpendicular to the optical axis in the decoupling path 29 a. A deflection mirror 33 is positioned, in the same way as the deflection mirror 22 , between the decoupling beam splitter 9 and the second DOE 30 . Another deflection mirror 34 is positioned between the axicon setup 31 b of the second lens group 31 and a coupling beam splitter 35 which is constructed as a polarization cube like the decoupling beam splitter 9 . The coupling beam splitter 35 is an example of a coupling element. The coupling beam splitter 35 is located in the optical path between the axicon setup 11 b of the first lens plane 11 and the optical raster element 13 . The illumination light guided onto the decoupling path 29 a is deflected by the coupling beam splitter 35 so that, downstream from the coupling beam splitter, it travels precisely along the optical axis 4 . High voltage, typically 5 to 10 kV, can be applied to the Pockels cell 8 in order to obtain a rapid change of illumination setting. When high voltage is applied to the Pockels cell 8 , the polarization of the illumination light can be rotated (e.g., from s to p) within a few nanoseconds. The p-polarized illumination light is extracted in the decoupling path 29 a because a polarizer in the decoupling beam splitter 9 acts as a reflector for p-polarization. In the decoupling path 29 a , the illumination light is subjected to different setting adjustment to the s-polarized illumination light which is not extracted. After deflection by the deflection mirror 34 via the coupling beam splitter 35 , the polarizer of which acts as a reflector for p-polarized light, p-polarized illumination light which has passed through the second optical module 29 is coupled again in the direction of the optical axis 4 . The light source 2 can generate, for example, laser pulses having a duration of 150 ns or 100 ns and a single pulse energy of, for example, 30 mJ or 15 mJ at a repetition rate of, for example, 6 kHz. FIGS. 2 to 4 show various examples of switching times for high-voltage switching instants t s of the Pockels cell 8 . FIGS. 2 to 4 all schematically show consecutive individual rectangular pulses L from the light source 2 at interval t z =t 2 −t 1 which corresponds to the reciprocal of the 6 kHz repetition rate. In the switching-time example in FIG. 2 , the Pockels cell 8 switches between every two laser pulses L. Laser pulse L 1 shown on the left in FIG. 2 passes through the Pockels cell without voltage being applied and therefore remains p-polarized. The polarization of subsequent laser pulse L 2 is rotated through 90° because switching instant t s has occurred and it therefore passes through the decoupling path 29 a . The next laser pulse (not shown) passes through the Pockels cell 8 without its polarization being altered. In the case of the switching-time example in FIG. 2 , every second laser pulse is therefore fed through the decoupling path 29 a whereas the other laser pulses are not decoupled. The reticle 19 is therefore subjected to alternate illumination with two different illumination settings which correspond to the setting of the optical modules 28 , 29 respectively and the laser pulses for each illumination setting have a repetition rate of 3 kHz. The radiation load incident on the reticle and the optical components of the illumination system downstream from the decoupling beam splitter 9 is determined by the energy and peak intensity of each individual laser pulse L. In the switching-time example in FIG. 3 , the Pockels cell 8 switches while a single laser pulse L is passing through it. Individual laser pulse L is therefore split into pulse parts L 1 , L 2 . In the example in FIG. 3 , polarization of the leading laser pulse part L 1 is unaffected and it therefore remains s-polarized. In contrast, the polarization of the subsequent laser pulse part L 2 is subjected to rotation because it passes through the Pockels cell 8 after switching instant t s , and is extracted and creates a different illumination setting to laser pulse part L 1 . The two laser pulse parts L 1 and L 2 have a pulse duration equivalent to roughly half the pulse duration of the non-divided laser pulse which, in this embodiment, is therefore around 50 or 75 ns. The energy of the laser pulse parts is roughly half the energy of individual laser pulses (7.5 mJ or 15 mJ). The polarization of leading laser pulse part L 2 of the subsequent laser pulse in FIG. 3 is rotated and is therefore p-polarized. Voltage is removed from the Pockels cell 8 at switching instant t s , so that the polarization of next laser pulse part L 1 is no longer affected and therefore remains s-polarized. This second laser pulse is therefore split. Switching repeats accordingly during laser pulses for subsequent laser pulses from the light source 2 which are not shown. In the switching-time example in FIG. 3 , one laser pulse part is therefore fed through the decoupling path 29 a , i.e. through the optical module 29 , and the other laser pulse part is fed through the other optical module 28 . In this switching-time example, the reticle 19 is illuminated at an effective repetition rate of 6 kHz with the first illumination setting and illuminated at the same effective repetition rate of 6 kHz with the second illumination setting. Because of the halving of the pulse energy in the laser pulse parts, the peak load on the reticle and the optical components downstream from the decoupling beam splitter 9 is reduced by a factor of roughly 2. In practice, this reduction factor can be even higher because the two different illumination settings generated by the optical modules 28 , 29 , in general, impinge on different regions of the pupil with different polarization characteristics. In the switching-time example in FIG. 4 , the Pockels cell 8 switches three times for each laser pulse L. In the case of leading laser pulse L shown on the left in FIG. 4 , high voltage is initially applied to the Pockels cell but this voltage is then switched off and applied again. The left-hand laser pulse shown in FIG. 4 is therefore split into leading laser pulse part L 1 with s-polarization, subsequent laser pulse part L 2 with p-polarization, yet another subsequent laser pulse part L 1 with s-polarization and final laser pulse part L 2 with p-polarization. In the case of laser pulse L shown on the right in FIG. 4 , these conditions are precisely reversed because when the Pockels cell 8 first switches during laser pulse L shown on the right in FIG. 4 , the high voltage is initially switched off. The right-hand laser pulse L shown in FIG. 4 therefore has a leading p-polarized laser pulse part L 2 , a subsequent s-polarized laser pulse part L 1 , a subsequent p-polarized laser pulse part L 2 and a final s-polarized laser pulse part L 1 . In the case of the switching-time example in FIG. 4 , the illumination light impinges on the reticle 19 with an effective repetition rate of 12 kHz for both illumination settings. In the case of the switching-time example in FIG. 4 , the light pulse parts L 1 and L 2 have a pulse duration of approximately 25 or 37.5 ns and a pulse energy of approximately 3.75 or 7.5 mJ. Because the individual light pulses are quartered by the triple switching of the Pockels cell 8 during one light pulse L, the peak load on the reticle 19 and on the optical components downstream from the decoupling beam splitter 9 drops by a factor of 4. Depending on polarization state, the service life of optical materials depends not only on peak illumination power H, but also on the number of pulses N and the pulse duration T of the laser pulses. Various theoretical models in relation to this, which are familiar to persons skilled in the art, have been developed. One of these models is the polarization double refraction model according to which the load limit of optical materials depends on the product H×N. With the so-called compaction model or the microchannel model, the load limit depends on the product H 2 ×N/T. Comparative analysis shows that it is possible to use a laser 2 with a halved repetition rate (number of pulses N/2), doubled pulse laser power (2H) and doubled pulse duration (2T) for double exposure by once-only changeover by the Pockels cell 8 during one laser pulse. Such lasers with a half repetition rate and doubled power are one possible way of increasing the performance of current lithographic lasers and can be implemented simply. Using the light-characteristic changer 8 makes it possible to use a 6 kHz laser in microlithographic applications which were previously only possible using a 12 kHz laser. The constructional requirements placed on the laser light source become commensurately less demanding. A polarization-changing light-characteristic changer other than the Pockels cell 8 can be used to influence the polarization of the illumination light, for example a Kerr cell. Instead of polarization, a different characteristic of the illumination light can be influenced by the light-characteristic changer, for example the light wavelength. In this case, dichroitic beam splitters can be used as the decoupling beam splitter 9 and as the coupling beam splitter 35 . The beam geometry of the light beam 3 or its direction can be the light characteristics that are modified by an appropriate light-characteristic changer in order to switch between the two optical modules 28 , 29 . A Kerr cell or an acousto-optic modulator can be used as an appropriate light-characteristic changer. An embodiment with two optical modules 28 , 29 is described above. It is equally possible to provide more than two optical modules and switch between them. For example, another Pockels cell which rotates the polarization of the illumination light at preset switching times, thereby causing extraction into another decoupling load which is not shown in FIG. 1 , can be provided between the decoupling beam splitter 9 and DOE 10 or in the decoupling path 29 a . This way, it is possible to obtain fast changeover between more than two illumination settings. The Pockels cell 8 can also be located inside the light source 2 and chop the laser pulses generated in the light source 2 into several light pulse parts of the same kind as parts L 1 and L 2 . This can result in little or no laser coherence and can, for example, reduce the possibility of undesirable interference in the mask plane 17 . FIG. 5 shows an embodiment of an illumination system. Components that are identical to those already described above with reference to FIGS. 1 to 4 have the same reference numerals and are not individually described again. The illumination system in FIG. 5 can be implemented in combination with all the design variations that are described above with reference to the embodiment in FIGS. 1 to 4 . In addition to the light source 2 , the illumination system 5 in FIG. 5 has another light source 36 , the internal construction of which can be identical to that of the light source 2 . Downstream from the light source 36 , there is a beam expander 37 , the construction of which can be identical to that of the beam expander 7 . A light beam 38 from the light source 36 is expanded by the beam expander 37 (e.g., as already described in connection with the light beam 3 from the light source 2 ). Downstream from beam expander 37 , there is a Pockels cell 39 . After exiting the other light source 36 , the light beam 38 is also initially s-polarized as indicated by dots 6 on the light beam 38 . As long as no voltage is applied to the Pockels cell 39 , the light beam 38 remains s-polarized after passing through the Pockels cell 39 . After the Pockels cell 39 , the light beam 38 impinges on a second decoupling beam splitter 40 . The light beam splitter 40 lets s-polarized light through and reflects p-polarized light to the right by 90° in FIG. 5 . A polarization-selective deflection element 41 is located downstream from the second decoupling beam splitter 40 in the beam splitter's forward direction. The deflection element is for s-polarized light which is incident from the direction of the second decoupling beam splitter 40 , reflecting to the right by 90° in FIG. 5 , and it lets p-polarized light through unimpeded. Using the illumination system 5 in FIG. 5 , light from the two light sources 2 and 36 can be injected optionally into the two optical modules 28 , 29 . When no voltage is applied to the two Pockels cells 8 and 39 , the light source 2 illuminates the first optical module 28 because s-polarized light beam 3 from the two decoupling beam splitters 9 and 40 is allowed through unimpeded. As long as no voltage is applied to the two Pockels cells 8 and 39 , the second light source 36 illuminates the second optical module 29 because the second decoupling beam splitter 40 lets the s-polarized light of the light beam 38 through unimpeded and this s-polarized light is deflected into the second optical module 29 by the deflection element 41 . When voltage is applied to the first Pockels cell 8 but not to the second Pockels cell 39 , the two light sources 2 and 36 illuminate the second optical module 29 . The now p-polarized light from the first light source 2 is extracted from the decoupling beam splitter 9 , as described above, into the decoupling path 29 a and, after deflection by the deflection mirror 33 , passes through the deflection element 41 unimpeded so that it can enter the second optical module 29 . The optical path of the light beam 38 from the second light source 36 remains unchanged. When voltage is not applied to the first Pockels cell 8 , but is applied to the second Pockels cell 39 , the two light sources 2 and 36 illuminate the first optical module 28 . The s-polarized light from the first light source 2 can pass through the two decoupling beam splitters 9 and 40 unimpeded and enters the first optical module 28 . The light of the light beam 38 from the second light source 36 rotated into p-polarization by the second Pockels cell is reflected through 90° by the second decoupling beam splitter 40 and enters the first optical module 28 . When light from the two light sources 2 and 36 collectively impinges on one of the optical modules 28 , 29 , the light from the two light sources 2 and 36 which collectively passes through the optical module 28 or 29 can have two different polarization states. P-polarized light which has passed through the first optical module 28 is reflected by the coupling beam splitter 35 in FIG. 5 upwards along the optical path 42 , from where it has to be brought back in the direction of the optical axis 4 by another appropriate coupling device. The same applies to s-polarized light which is fed through the second optical module 29 and which passes through the coupling beam splitter 35 , without being deflected thereby, in the direction of the optical path 42 . When voltage is applied to the two Pockels cells 8 and 39 , light from the light source 2 is conducted through the second optical module 29 and light from the light source 36 is conducted through the first optical module 28 . FIGS. 6 and 7 show the possible characteristics, as a function of time, of the intensities I 1 of the light pulses L from the first light source 2 and of the intensities I 2 of the light pulses L′ from the second light source 36 . The two light sources 2 and 36 are synchronized with each other so that light pulses L′ are generated during the gaps between two light pulses L. Two light pulses L and L′ therefore do not impinge simultaneously on the second decoupling beam splitter 40 and the deflection element 41 . Also, beyond the coupling beam splitter 36 , laser pulses L and L′ do not simultaneously impinge on downstream optical components of the illumination system 5 or on the reticle 19 and the wafer 24 . As described above with reference to FIGS. 2 to 4 , laser pulses L and L′ can be split into two or more laser pulse parts L 1,2 and L′ 1,2 by one or more optical polarization components and appropriate switching times. This reduces the illumination light load on the optical components as already described above with reference to FIGS. 2 to 4 . Two pulsed light sources with pulse waveforms according to FIGS. 6 and 7 can also be combined upstream from a single Pockels cell of the illumination system. To achieve this, light 3 , for example, from the second light source 2 upstream from beam expander 7 can be injected into the optical path of the light beam 3 with the aid of a perforated mirror 2 a which is tilted 45° relative to the optical axis 4 . The light source 2 ′, the light beam 3 ′ and the perforated mirror 2 a are shown in a dashed line in FIG. 1 . The light beam 3 ′ is also s-polarized. The light beam 3 ′ from the light source 2 ′ ideally has a mode which carries practically no energy in the region of a central hole in the perforated mirror 2 a . The light beam 3 from the light source 2 passes through the hole in the perforated mirror 2 a . The beam expander 7 is then illuminated by merged light beams 3 and 3 ′. The Pockels cell 8 is then used as a common Pockels cell in order to influence the polarization state of the light beams 3 and 3 ′. FIGS. 8 and 9 show another way of reducing the illumination light load on individual components of the illumination system 5 in FIG. 5 in situations where the light pulses L and L′ of the two light sources 2 and 36 overlap in time. FIG. 8 shows the intensity I 1 of the light pulses L from the light source 2 . FIG. 9 shows the intensity I 2 of the light pulses L′ from the light source 36 . The Pockels cell 8 is deenergized before the arrival of the first laser pulse L at t=t s0 . Laser pulse part L 1 therefore passes through the first optical module 28 . The second Pockels cell 39 is also deenergized at t=t s0 in synchronism with the first Pockels cell 8 . Switching instant t s0 coincides with the centre of a laser pulse L′ of the second light source 36 , so that subsequent light pulse part L′ 2 is then conducted through the second optical module 29 . In period T D between the rising edge of laser pulse L and the trailing edge of laser pulse L′ following switching instant t s0 during which the two laser pulses L and L′ overlap, the two laser pulses L and L′ are therefore separately conducted through the optical modules 28 , 29 so that there is no simultaneous loading by the two laser pulses L and L′. At the next switching instant t s1 , voltage is applied to the two Pockels cells 8 and 30 in synchronism. Switching instant t s1 coincides with the centre of laser pulse L of the light source 2 . Subsequent laser pulse part L 2 therefore passes through the second optical module 29 . In contrast, laser pulse part L′ 1 of next laser pulse L′ of the second light source 36 which overlaps with this laser pulse part L 2 is conducted through the first optical module 28 . At switching instant t s2 in the centre of next laser pulse L′, the process described with reference to switching instant t s0 repeats. The frequency of switching instants t s is twice that of the laser pulses of individual light sources 2 and 36 , with laser pulse L and L′ of one light source being halved and with switching between two laser pulses L′ and L of the other light source. This circuit ensures that light from the two light sources 2 and 36 is never conducted through a single optical module 28 or 29 and this reduces the load on the individual optical components of the optical modules 28 , 29 accordingly. FIG. 10 shows an embodiment of the illumination system 5 . Components that are identical to those already described above with reference to FIGS. 1 to 9 have the same reference numerals and are not individually described again. The variation in FIG. 10 is equivalent to the variation in FIG. 5 , apart from the way in which the light from the second light source 36 is extracted. In FIG. 10 , the decoupling beam splitter 9 , which already extracts the light beam 3 of the light source 2 , is used to extract the light beam 38 of the second light source 36 . The decoupling beam splitter 9 firstly lets the s-polarized light of the light source 2 and secondly lets the s-polarized light of the light source 36 through unimpeded, so that s-polarized light from the light source 2 impinges on the first optical module 28 and s-polarized light from the second light source 36 impinges on the second optical module 29 . The decoupling beam splitter 9 reflects the p-polarized light of the light sources 2 and 36 through 90° respectively, so that p-polarized light from the second light source 36 impinges on the first optical module 28 and p-polarized light from the first light source 2 impinges on the second optical module 29 . In terms of coupling, the variation in FIG. 10 corresponds to that in FIG. 5 . In terms of the switching times of the Pockels cells 8 and 39 , the examples of switching times described above with reference to FIGS. 6 to 9 can also be used in the system shown in FIG. 10 . In some embodiments, the change in light characteristic in order to change the optical path between the optical modules 28 , 29 can take place in one second or less (e.g., one microsecond or less, 100 ns or less, 10 ns or less). Switching of the Pockels cells 8 and 39 can be periodic at a fixed frequency. This frequency can be around 1 kHz, for example. Other exemplary frequencies are in the range from 1 Hz to 10 kHz. By changing the light characteristic, it is believed that it is possible to ensure that the maximum laser power per laser pulse after creating an illumination setting in the pupil plane 12 is at least 25% lower than it would be using a conventional illumination system with the same setting measured at the same location. The maximum intensity at a specific location in the illumination system can be, for example, up to 25% lower in the case of the designs according to the disclosure than in the case of conventional illumination systems with just one optical module. Instead of the coupling beam splitter 35 , an optical system which integrates the two optical paths can be provided in the form of, for example, a lens, an objective or a refractive mirror or a plurality of such mirrors. One example of such an optically integrating system is described in WO 2005/027207 A1. FIG. 11 shows an embodiment of a projection exposure apparatus 1 configured to produce proportional illumination of the illumination field via the first optical module 28 , on the one hand, and via the second optical module 29 , on the other hand, e.g. for specified double exposure of the reticle 19 using the two illumination settings that can be set via the optical modules 28 , 29 . Components of the projection exposure apparatus 1 in FIG. 11 that are identical to those already described above with reference to the projection exposure apparatus 1 in FIGS. 1 to 10 have the same reference numerals and are not individually described again. The project exposure apparatus 1 in FIG. 11 has a main control system in the form of, for example, a computer 43 (e.g., to specify proportional illumination). The computer 43 is connected to a control module 45 by a signal cable 44 . The control module 45 is connected by signals to the light source 2 by a signal cable 46 , to a light source 2 ′ by a signal cable 47 and to the Pockels cell 8 by a signal cable 48 . The computer 43 is connected to the zoom systems 11 a and 31 a by the signal cables 49 and 50 . The computer 43 is connected to the axicon setups 11 b and 31 b by signal cables 51 and 52 . The computer 43 is connected to the REMA 16 by a signal cable 53 . The computer 43 is connected to the wafer stage 26 by a signal cable 54 and to the reticle stage 23 by a signal cable 55 . The computer 43 has a display 56 and a keyboard 57 . The computer 43 specifies the switching instants t s for the Pockels cell 8 . By selecting the switching instants over time with the aid of the computer 43 , it is possible to specify the intensity with which reticle 19 is illuminated using either of the two illumination settings that can be produced via the two optical modules 28 , 29 . The switching instants for the Pockels cell 8 can be synchronized with trigger pulses of the light sources 2 and 2 ′ so that switching instants occur in correct phase relation during laser pulses as described above in connection with FIGS. 2 to 8 . Switching instants t S are specified depending on the particular illumination settings previously set in the optical modules 28 , 29 . The computer 43 receives information regarding the particular previously set illumination setting over the signal cables 49 to 52 . The computer 43 can also actively set a predefined illumination setting by controlling appropriate displacement drives for the zoom systems 11 a and 31 a and for the axicon setups 11 b and 31 b over the corresponding signal cables. Switching instants t s are also specified depending on the particular scanning process. The computer 43 receives information concerning this from the REMA 16 and stages 23 and 26 via the signal cables 53 to 55 . Depending on the specified value, the computer 43 can also actively change the operating position of the REMA 16 and stages 23 and 26 by controlling appropriate drives via the signal cables 53 to 55 . This way, the computer 43 can, depending on the particular operating situation of the projection exposure apparatus 1 , make sure that each of the two optical modules 28 , 29 contributes sufficient light to illuminate the illumination field on reticle 19 . The computer 43 determines the relevant light contribution by integrating the intensity curves (cf. FIGS. 2 to 4 and FIGS. 7 to 9 ). Any excess light which is not needed for projection exposure can be coupled out of the exposure path by using a second Pockels cell and a downstream polarizer. The main control system 43 can also be connected by signals to the decoupling element 9 and/or coupling element 35 if this is necessary in order to specify proportional illumination of the illumination field using the illumination settings that can be achieved via the optical modules 28 , 29 . The main control system 43 makes time-proportional illumination of the illumination field on the reticle 19 possible via the first optical module 28 and the second optical module 29 . Alternatively or additionally, the main control system 43 can also be used to obtain intensity-proportional illumination of the illumination field via the first optical module 28 and the second optical module 29 . For instance, it is possible to illuminate the illumination field at 30% of total intensity via the first optical module 28 and at 70% of total intensity via the second optical module 29 . This can be performed statically so that these percentages do not change over a predefined period. Alternatively, it is also possible to vary these proportions dynamically. To achieve this, the Pockels cell 8 can be driven, for example, by a sawtooth waveform having 1 ns timebase. To achieve this, the control circuit of the Pockels cell 8 can have a least one high-voltage generator. If fast switching between two voltages is desirable, the control circuit of the Pockels cell 8 can have two high-voltage generators. Besides high-voltage switching on a nanosecond timescale, there can also be additional high-voltage switching, for example on a millisecond timescale, so that, measured against the duration of the laser pulses, slow transitions between illumination settings that can be specified via the optical modules 28 , 29 are possible. FIG. 12 shows an embodiment of the projection exposure apparatus 1 . Components that are identical to those already described above with reference to FIGS. 1 to 11 have the same reference numerals and are not individually described again. In contrast to the projection exposure apparatus in FIGS. 1 , 5 , 10 and 11 , the projection exposure apparatus 1 in FIG. 12 has pupil forming planes 58 and 59 which are each located in the optical paths to the optical modules 28 , 29 and are therefore directly assigned to them. The pupil forming plane 58 is directly downstream from the axicon setup 11 b of the first optical module 28 . The pupil forming plane 59 is directly downstream from the axicon setup 31 b of the second optical module 29 (located in the decoupling path 29 a ). In the embodiment in FIG. 12 , the pupil forming planes 58 and 59 replace the pupil forming plane 12 in FIG. 12 . Alternatively, it is possible for the pupil forming planes 58 and 59 to be optically conjugate with the pupil forming plane 12 . Individual raster elements corresponding to raster element 13 in the projection exposure apparatus 1 in FIG. 1 can be assigned to the pupil forming planes 58 and 59 . In the case of the embodiment of the illumination system 5 in FIG. 12 , pupil forming, i.e. setting an illumination setting, can be performed by using appropriate optical components in optical modules 28 , 29 , as is known in principle from the prior art, e.g. from WO 2005/027207 A. Other components for influencing a pupil setting which can be used in optical modules 28 , 29 are described in WO 2005/069081 A2, EP 1 681 710 A1, WO 2005/116772 A1, EP 1 582 894 A1 and WO 2005/027207 A1, which are hereby incorporated by reference. FIG. 13 shows an embodiment of the illumination system 5 of the projection exposure apparatus 1 . Components that are identical to those already described above with reference to FIGS. 1 to 12 have the same reference numerals and are not individually described again. In contrast to the illumination systems 5 in FIGS. 1 to 12 , the mechanism for obtaining decoupling between optical modules 28 , 29 in the case of the illumination system 5 in FIG. 13 is not based on influencing a light characteristic which is subsequently used to alter an optical path, but on directly influencing the path of the illumination light. To achieve this, the decoupling element 60 is provided in the form of a mirror element. The decoupling element 60 is located at the position of the decoupling beam splitter 9 , e.g. in the embodiment in FIG. 1 , and can rotate around axis 61 which lies in the projection plane of FIG. 13 . This rotating movement is driven by a rotary drive 62 . The rotary drive 62 is connected to synchronization module 63 by the signal cable 64 . The decoupling element 60 has a disc-shaped mirror mount 65 , part of which is shown in FIGS. 13 and 14 . A multiplicity of individual mirrors 67 are fitted over the circumferential wall 66 of the mirror mount 65 and project beyond said wall. The representation in FIG. 14 is not true scale. In fact, there can be a large number of individual mirrors 67 , for example several hundred such individual mirrors, on the mirror mount 65 . In the circumferential direction, the gap between two adjacent individual mirrors 67 is equivalent to the circumferential extent of a single mirror 67 . The individual mirrors 67 all have the same circumferential extent. When the mirror mount 65 rotates, illumination light is either reflected by one of the mirrors 67 or passes between the individual mirrors 67 and is uneffected. Reflected illumination light impinges on the decoupling path 29 a , i.e. the second optical module 29 . Illumination light which is let through impinges on the first optical module 28 . In the case of the embodiment in FIG. 13 , a coupling element 68 is located at the position of the coupling beam splitter 35 in the embodiment in FIG. 1 and the coupling element 68 has precisely the same structure as the decoupling element 60 . The coupling element 68 is only shown schematically in FIG. 13 . The coupling element 68 , controlled by control module 63 , is driven in synchronism with the decoupling element 60 so that whenever the decoupling element 60 lets illumination light through, the coupling element 68 also lets illumination light through unaffected. In contrast, when the decoupling element 60 reflects illumination light with one of the mirrors 67 , this extracted illumination light, after passing through the decoupling path 29 a , is reflected by a corresponding individual mirror of the coupling element 68 and is thereby injected into the adjacent common illumination light ray path towards reticle 19 . The speed of rotation of the coupling element 60 and that of the decoupling element 68 is synchronised with the pulse sequence from the light sources 2 and 2 ′. Owing to the aspect ratio of the circumferential extent of the individual mirrors 67 relative to the circumferential extent of the gaps between adjacent the individual mirrors 67 of the decoupling element 60 and of the coupling element 68 , it is possible to specify the proportion of illumination via the first optical module 28 on the one hand and via the second optical module 29 on the other hand. Such aspect ratios can be defined by the configuration and arrangement of the individual mirrors 67 on the circumferential wall 66 of the mirror mount 65 (e.g., from 1:10 to 10:1). FIG. 15 shows an embodiment of the decoupling element 60 which can also be used in this form as the coupling element 68 . The decoupling element 60 is in the form of strip-shaped mirror foil 69 . The mirror foil 69 is divided up into individual mirrors 70 between which there are transparent gaps 71 through which illumination light can pass. The mirror foil 69 is an endless loop which is transported over corresponding guide rollers so that, at the location of the individual mirrors 67 in the embodiment in FIG. 13 , it is transported perpendicularly to the plane of projection through the ray path of illumination light 3 . In general, as long as illumination light is reflected by one of the individual mirrors 70 , it is reflected by the decoupling element 60 into the decoupling path 29 a and injected by the coupling element 68 back into the common ray path towards reticle 19 . The illumination light is not affected by the transparent gaps 71 so that, in the case of the decoupling element 60 , it passes through to the first optical module 28 and, in the case of the coupling element 68 , it passes through to reticle 19 . The explanations given above regarding aspect ratios in connection with coupling and decoupling elements 60 and 68 in FIG. 14 also apply to the control of the mirror foil 69 driven via control module 63 and to the aspect ratio of the lengths of the individual mirrors 70 and the lengths of the gaps 71 . FIG. 16 shows a polarization changer 72 which can be used instead of the decoupling element 60 . The polarization changer 72 is installed in the illumination system 5 in FIG. 1 at the location of the Pockels cell 8 . The polarization changer 72 is rotatably driven around the rotation axis 76 which runs parallel to the light beam 3 between the light source 2 and the decoupling beam splitter 9 . The polarization changer 72 is rotatably driven around the rotation axis 76 by an appropriate rotary drive synchronised via control module 63 . The polarization changer 72 has a revolving support 73 with a total of eight revolving receptacles 74 . A significantly larger number of receptacles 74 is possible. A λ/2 plate 75 is fitted in every second receptacle 74 in the circumferential direction. The other four receptacles 74 are empty. The optical axes of the four λ/2 plates 75 in total are therefore arranged so that, when one of the λ/2 plates 75 is in the ray path of the illumination light, the polarization of the illumination light is rotated through 90° as it passes through the λ/2 plate. The polarization changer 72 then has the same function as the Pockels cell 8 when high voltage is applied to it. When one of the empty receptacles 74 lets the illumination light through unaffected, the polarization changer 72 functions as a deenergized Pockels cell. A rotatable polarization-changing plate as described, for example in WO 2005/069081 A can be used as an alternative to the polarization changer 72 . A λ/2 plate placed in the ray path of illumination light beam 3 , for example at the location of the Pockels cell 8 in the setup in FIG. 1 and which replaces the Pockels cell 8 , can also be used as another alternative to the polarization changer 72 . By rotating the λ/2 plate around a rotation axis parallel to illumination light beam 3 which passes through it, the polarization plane of the illumination light can be rotated through 90°, for example, so that the λ/2 plate has a polarization-changing effect equivalent to that of the Pockels cell 8 in the embodiment in FIG. 1 . The optical axis of the λ/2 plate is in the plane of the plate as a rule. Other orientations of the optical axis of the λ/2 plate relative to the plane of the plate are also possible. Polarization-changing elements of the same kind as λ/2 plates are described, for example, in DE 199 21 795 A1, US 2006/0055834 A1 and WO 2006/040184 A2, which are hereby incorporated by reference. Embodiments are described above assuming that the illumination system already includes two optical modules 28 , 29 . According to the disclosure, it is also possible to retrofit existing projection exposure apparatuses having an optical module equivalent to the first optical module 28 in the embodiments described above with a supplementary module, thereby producing one of the embodiments described above. The retrofit supplementary module includes, besides the second optical module 29 , the decoupling element 9 or 60 and the coupling element 35 or 68 . Depending on the design of the supplementary module, it also has a light-characteristic changer, for example the Pockels cell 8 or the polarization changer 72 . The main control system 43 may also be part of the supplementary module. The supplementary module may also include another light source 2 ′ or 36 with appropriate coupling and decoupling optics (e.g., as described above in connection with FIGS. 1 and 5 ). Embodiments have been described with reference to two differing illumination settings having differing spatial intensity distributions in the pupil or pupil plane 12 . The term “illumination setting” refers not only to the spatial intensity distribution but also to the spatial polarization distribution in the pupil. Using the at least two optical modules 28 , 29 , it is also possible to adjust a single spatial illumination setting with regard to the spatial intensity distribution in the pupil plane 12 , the illumination settings differing merely in terms of their spatial polarization distribution in the pupil plane 12 . Depending on the structures to be imaged, the second illumination setting can, for example, have a polarization distribution rotated through 90° in the pupil plane 12 relative to the polarization distribution of the first illumination setting in the pupil plane 12 . It is thus possible, by suitable activation of the two optical modules 28 , 29 , to control the proportional illumination thereof using a control unit, such as for example the computer 43 , so as to allow, for a single intensity illumination setting with which the reticle 19 is illuminated, various polarization states to be achieved during the illumination. This can be advantageous, for example, if manufacturing processes are to be transferred from development installations in development centres to production installations in factories for manufacturing microstructured components or chip factories and these differing installations, in particular the projection objectives thereof for imaging mask structures onto the wafer, differ in terms of their polarization transfer characteristics. In such a case, it can be advantageous if, for a single intensity illumination setting, the development of which has been found to be optimal for a specific chip structure, use of the two optical modules allows the polarization characteristic to be controlled, so the production installations operated therewith also image optimum chip structures onto the wafer. Another application of the change in polarization characteristic at a single intensity illumination setting is obtained on illumination of chips in a scanning process in which, although a single intensity illumination setting was selected for illuminating the entire chip, the chip structures in differing regions of the chip can be imaged with higher contrast by differing polarization. In this case, it can be desirable to vary the polarization characteristics during the scanning process. In addition, the spatial intensity distribution of the illumination settings (e.g., intensity illumination setting), generated by the at least two optical modules, can also be altered during the scanning process. A further aspect in the change in polarization characteristics at a single illumination setting can be obtained from what is known as polarization-induced birefringence. This is a material effect based on the fact that polarized irradiation of the material causes over time stress birefringence in the material through which the illumination light passes. Such material regions with illumination-induced stress birefringence form defect regions in the material. In order to prevent these material defects, circular or unpolarized light is, if possible, used. The present disclosure can allow the polarization characteristic to be altered at a single intensity illumination setting, thus allowing polarization-induced birefringence to be reduced, at least for the optical components following the coupling element. Based on the foregoing embodiments, it is also possible using the at least two optical modules 28 , 29 to generate any desired illumination settings having any desired polarization distributions in the pupil plane 12 . It is in this case also possible to change rapidly between the illumination settings having the corresponding polarization states—up to a plurality of changes within a light pulse. Furthermore, it is possible to allow slow changes of the illumination settings in synchronism with the scanning process and at the same time to alter the polarization distribution within the at least two optical modules 28 , 29 using appropriate polarization-influencing optical elements, such as for example a polarization rotation unit as described in WO 2006/040184 A2 or a rotatable λ/2 plate as disclosed, for example, in WO 2005/027207 A1, which are arranged in the modules 28 , 29 or in the beam direction after these modules, for example in time correlation with the scanning process. Polarization-influencing optical elements as presented, for example, in WO 2006/040184 A2 can allow relatively fast changes in the polarization characteristic within the two modules 28 , 29 . The disclosure therefore provides the flexibility to illuminate chip structures or combinations of differing chip structures of wafer partial regions, for example during the scanning process, with intensity illumination settings adapted to the requirements for imaging and/or spatial polarization distributions in the pupil plane of the projection exposure apparatus for imaging which is optimised with regard to contrast and resolution. For chip manufacturers, this can open up new possibilities for arranging differing chip structures on a wafer, as the disclosure allows combination of chip structures which, owing to the various requirements placed on the necessary illumination settings, may have been previously avoided on a single wafer or may have been imaged only with relatively high integration density. With the foregoing embodiments, it is equally possible to provide, using the at least two optical modules 28 , 29 , a single intensity illumination setting even with the same spatial polarization distribution, i.e. two illumination settings which are similar within predetermined tolerances, in the pupil plane 12 . This is, for example, advantageous if during the scanning process double exposure with two differing settings and/or differing polarization states would be inappropriate for specific partial regions of a chip, for the high-contrast imaging of chip structures into the partial region. A further potential advantage of operating the two optical modules 28 , 29 with identical illumination settings and identical spatial polarization distributions in the pupil plane 12 is that, on switching during the light pulse according to the switching-time example in FIG. 3 , the peak load or, on switching between the light pulses according to the switching-time example in FIG. 2 , the permanent load on the optical components in the two optical modules 28 , 29 is reduced compared to operation of an identical illumination setting with the same polarization distribution in a conventional illumination system or compared to operation of the illumination setting in merely one of the two optical modules 28 , 29 . FIGS. 18 to 29 specify examples of combinations of differing illumination settings in the pupil plane 12 with associated mask structures. The examples specified in FIGS. 18 , 19 , 22 , 23 , 26 and 27 are merely a small selection of the illumination settings achievable by the disclosure. The terms “sigma inner (inner σ)”, “sigma outer (outer σ)” and “polar width” will be used hereinafter for the purposes of characterization. The inner σ is in this case defined as the pupil radius in which 10% of the illumination light intensity is in the pupil. The outer σ is in this case defined as the pupil radius in which 90% of the illumination light intensity is in the pupil. The polar width is defined as the opening angle between radii which delimit a structure illuminated in the pupil plane and at which the intensity has fallen to 50% of the maximum intensity of this structure. FIG. 18 shows an illumination setting in the form of dipole illumination in the X-direction having a polar width of 35°, an inner σ of 0.8 and an outer σ of 0.99. FIG. 19 shows a further illumination setting in the form of a dipole illumination in the Y-direction having a polar width of 35°, an inner σ of 0.3 and an outer σ of 0.5. The illumination setting in FIG. 18 can in this case be provided by the module 28 and the illumination setting in FIG. 19 by the module 29 or vice versa. If these illumination settings are to be operated in a polarized manner, it is advantageous if the illumination setting in FIG. 18 is polarized linearly in the Y direction. The polarization direction of the illumination setting in FIG. 19 is in this case not crucial for the imaging contrast as owing to the maximum outer σ of 0.5 the light beams strike the wafer while still at moderate angles in contrast to the illumination setting in FIG. 18 . FIGS. 20 and 21 show exemplary mask structures that can be illuminated and imaged with good imaging quality during a scanning process by double exposure or change-over of the illumination settings in FIGS. 18 and 19 provided by the optical modules 28 , 29 . The mask structure in FIG. 20 is in the form of thick vertical lines having an extension in the Y direction of 50 nm wide and a 50 nm spacing between the lines in the X direction. The mask structure in FIG. 21 is in the form of horizontal and vertical lines having a width greater than 100 nm. In the latter case, the lines are said to be isolated. The simultaneous imaging of structures in FIGS. 20 and 21 is a typical application in which on a mask in one direction relatively low width structures and at the same time in the same direction or perpendicularly thereto relatively non-low width structures are to be transferred via illumination onto the wafer. Depending on whether on a mask the aforementioned thick and isolated lines from FIGS. 20 and 21 are formed adjacently to or set apart from one another, the double exposure or the change-over or a mixture of double exposure and change-over of the illumination settings in FIGS. 18 and 19 , correlated with the scanning process, will prove to be optimal for imaging the mask structures of FIGS. 20 and 21 . The illumination setting in FIG. 18 is suitable for the high-contrast imaging of a mask having exclusively thick lines corresponding to the mask structure in FIG. 20 and the illumination setting in FIG. 19 is suitable for high-contrast imaging of a mask having exclusively isolated lines corresponding to the mask structure in FIG. 21 . FIG. 22 shows an illumination setting in the form a quasar or quadrupole illumination having poles with 35° polar width along the diagonal between the X and Y direction with an inner σ of 0.8 and an outer σ of 0.99. FIG. 23 shows an illumination setting in the form of a conventional illumination with an outer σ of 0.3. The illumination setting in FIG. 22 can in this case be provided by the module 28 and the illumination setting in FIG. 23 by the module 29 or vice versa. If these illumination settings are to be operated in a polarized manner, it is advantageous if the illumination setting in FIG. 22 is linearly polarized tangentially to the optical axis. The foregoing remarks concerning the polarization direction of the illumination setting in FIG. 19 accordingly apply to the polarization direction of the illumination setting in FIG. 23 . FIGS. 24 and 25 show mask structures which are to be provided by double exposure or change-over of the illumination settings in FIGS. 22 and 23 during a scanning process. These structures are relatively high packing density ( FIG. 24 ) and relatively non-high packing density ( FIG. 25 ) contact holes having a width of, for example, 65 nm. Depending on whether on a mask the aforementioned high packing density contact holes and non-high packing density contact holes from FIGS. 24 and 25 are formed adjacent to or set apart from one another, the double exposure or change-over or a mixture of double exposure and change-over of the illumination settings in FIGS. 22 and 23 , correlated with the scanning process, will be found to be optimal for imaging the mask structures from FIGS. 24 and 25 . The illumination setting in FIG. 22 is suitable for the high contrast imaging of a mask having exclusively relatively high packing density contact holes corresponding to the mask structure of FIG. 24 and the illumination setting in FIG. 23 can be best suited for the high-contrast imaging of a mask having exclusively non-high packing density contact holes corresponding to the mask structure of FIG. 25 . FIG. 26 shows an illumination setting in the form of an X-dipole illumination having poles with 35° polar width in the X direction with an inner σ of 0.8 and an outer σ of 0.99. FIG. 27 shows an illumination setting in the form of a Y-dipole illumination having poles with 35° polar width in the Y direction with an inner σ of 0.8 and an outer σ of 0.99. The illumination setting in FIG. 26 can in this case be provided by the module 28 and the illumination setting in FIG. 27 by the module 29 or vice versa. If these illumination settings are to be operated in a polarized manner, it is advantageous if the illumination setting in FIG. 26 is polarized linearly in the Y direction and the illumination setting in FIG. 27 is polarized linearly in the X direction. FIGS. 28 , 29 show the two masks which are successively to be imaged onto the same wafer to be illuminated by double exposure with the illumination settings in FIGS. 26 and 27 during two scanning processes. These masks are thick horizontal ( FIG. 28 ) and vertical ( FIG. 29 ) structures having a width of, for example, 50 nm and a line spacing of, for example, 50 nm. In contrast to the foregoing examples, for imaging the two masks in FIGS. 28 , 29 there is carried out a double exposure in which there is carried out on the same wafer to be illuminated, in a first step, a scanning process with the mask in FIG. 28 and the illumination setting in FIG. 26 and, in a second step, a second scanning process with the mask in FIG. 29 and the illumination setting in FIG. 27 . Two different illuminations are thus carried out on the same wafer with the differing masks. This double exposure with the differing masks therefore differs from the double exposure or change-over in a single mask in which merely the illumination setting with which the mask is illuminated is changed. It is also possible in this case for the two separate masks to be arranged next to each other in the reticle or mask plane and to be moved in the scanning direction by component 23 for holding and manipulating the masks or reticles. In this case, there is no need for a complex change of masks between the two illuminations and the masks can be successively transferred onto the same wafer to be illuminated in a single scanning process instead of in two scanning processes carried out in succession. Owing to the high scanning speed of the component 23 , which is responsible for the high wafer throughput of the projection exposure apparatus, it is necessary to change the illumination settings for the two masks very rapidly during transfer of the masks in the one scanning process. In principle, it is not compulsory for the two separate masks to be arranged in the same plane. In principle, the two masks can also be arranged in various planes, the projection exposure apparatus being adapted during the change between the masks arranged in various planes by appropriate and optionally automatic adjustment of optical components. In all of the above-mentioned illumination settings in FIGS. 18 , 19 , 22 , 23 , 26 and 27 , the double or multiple exposure according to the disclosure of a mask with the two illumination settings in FIGS. 18 and 19 , 22 , 23 , 26 and 27 with switching times of up to 1 ns or the change-over according to the disclosure of the two settings allows precise monitoring and optimization of the light intensity within the two settings. This can allow for the scanning process with a mask structure in FIGS. 20 , 21 , 24 , 25 , 28 and 29 good (e.g., optimum) structures and structure widths to be achieved on the wafer to be illuminated. It is in this case also possible for the two zoom-axicon groups 11 , 31 of the two optical modules 28 , 29 to be controlled over a slower time scale during the scanning process in order to alter the inner and outer minimum or maximum illumination angles, defined by the two respectively utilized illumination settings. A further potential advantage of operating the at least two optical modules 28 , 29 with identical or differing illumination settings and with identical or differing polarization distributions in the pupil plane 12 is obtained on switching during the light pulse in accordance with the switching-time example in FIG. 3 if, within an optical module 28 or 29 , use is made of an optical component 80 which delays the partial light pulse of the module (see FIG. 17 ). The optical component 80 may, for example, consist of a correspondingly folded optical delay line, of at least two mirrors or of corresponding equivalents which allow the light propagation time to be extended. Switching during the light pulse in accordance with the switching-time example in FIG. 3 allows, as stated hereinbefore, a laser having an output with a repetition rate of 12 kHz to be produced from a laser having a repetition rate of, for example, 6 kHz. The optical component 80 in FIG. 17 then delays the partial light pulse of the illumination light in the optical module 29 in relation to the other partial light pulse of the illumination light in the other optical module 28 with regard to the light propagation time in such a way that, for example, the partial light pulses from the one module 28 are mutually time-shifted with respect to the partial light pulses from the other module in such a way that chronologically equidistant light pulses arrive on the reticle 19 to be illuminated. In this case, the light pulses L 1 , L 2 are time-delayed by the interval of adjacent laser pulses L at the location at which they were separated at the switching instant t s , so all the laser pulse parts L 1 , L 2 generated by the switching are at the same intervals from one another after the coupling element. Thus, for example, not only can a 6 kHz laser be split up to form a 12 kHz laser, the dose per time interval of the split 12 kHz laser can, for example, also be controlled so as substantially to correspond to the dose per time interval of a real 12 kHz laser. This is important for a scanning process with pulsed light sources, as it has to be ensured that each partial region of a chip is given the same dose of light during the scanning process. If, as mentioned hereinbefore, the two modules 28 , 29 are operated proportionally, i.e. with, in their dose, differing partial light pulses in the period of time and/or with varying intensity, a chronologically non-equidistant pulse sequence of the light pulses arriving on the reticle 19 from the two modules 28 , 29 may be beneficial with regard to the dose. It should be noted that the above-mentioned polarization setting within the two optical modules 28 , 29 or thereafter is not only beneficial with regard to the adjustment of the spatial polarization distribution in the pupil plane 12 for the respective illumination settings, as for example in FIG. 18 , 19 , 22 , 23 , 26 or 27 ; it is also beneficial to preserve a certain polarization state which is varied by the two optical modules 28 , 29 themselves, the subsequent lens system, the reticle 19 , the projection objective 20 and/or by a photoresist layer of the wafer 24 to be illuminated. It is thus possible to provide on the wafer 24 the polarization state respectively required for high-contrast imaging even if the polarization state changes in the light path from the polarization-influencing optical elements to the wafer 24 . This preservation of a spatial polarization distribution may also prove beneficial only during operation of a projection exposure apparatus if, owing to slow changes in the optical characteristics of the optical elements of the illumination system 5 , the projection objective 20 and the reticle 19 , these optical elements alter the polarization state of the light passing therethrough. Slow changes of this type may, for example, be brought about by thermal drifts. As an alternative to switching the polarization using a Pockels cell 8 ; 39 or a Kerr cell, use may also be made of a magneto-optic switch based on the Faraday effect. As an alternative to the aforementioned switching or decoupling using the light wavelength as the exchangeable light characteristic, Raman cells, as described in U.S. Pat. No. 4,458,994, or Bragg cells, as described in U.S. Pat. No. 5,453,814, may be used. U.S. Pat. No. 4,458,994 and U.S. Pat. No. 5,453,814 are hereby incorporated by reference. Use may be made for this purpose of a photoelastic modulator (PEM) such as is described, for example, in US 2004/0262500 A1, which is hereby incorporated by reference. As an alternative to the aforementioned possible switching or decoupling elements, use may also be made of combinations of the aforementioned options, especially combinations in which at least one component operates of the basis of an electro-optical or magneto-optical principle. Other embodiments are in the claims.

Optics, such as, for example, microlithographic projection exposure apparatus illumination optics, as well as related systems, methods, components and devices are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority benefit of U.S. Provisional Patent Application Ser. No. 61/581,496 filed Dec. 29, 2011, and entitled “Dual Filter Cartridge and Frame Apparatus and Method of Use.” The disclosure of the aforementioned Provisional Patent Application Ser. No. 61/581,496 is hereby incorporated by reference in its entirety. BACKGROUND [0002] Filtering toxic compounds from blood has been an area of great importance for human health. Filters for adsorption of toxic compounds from blood are known in the art. An example is the use of extracorporeal filters to remove chemotherapeutic drugs from the blood stream during cancer treatments such as in hepatic chemosaturation therapy. This therapy also known as percutaneous hepatic perfusion (PHP) delivers ultra-high doses of intra-arterial chemotherapy directly into the isolated liver, saturating both the liver and the tumor cells. The blood from the liver is drained through an isolation-aspiration catheter, and then directed outside the body to specially designed, and often proprietary, filters which reduce the concentration of chemotherapeutic agent before this blood is returned to the body. The potential of chemosaturation therapy includes: the ability to administer higher doses of chemotherapeutic agent to a particular organ than could be delivered with traditional systemic-intravenous methods while significantly reducing systemic exposure to the high dose levels. [0003] The filters used to absorb the drug from the blood are incorporated in an extracorporeal circuit. The blood drained from the liver through the isolation aspiration catheter is pumped by a venous bypass pump, such as is used in heart bypass surgery, through a filter or set of filters. The outlet of the filter(s) is connected by a tube set to a return catheter inserted in a central vein, through which the cleaned blood is returned to the patient's circulatory system. In use, the filter(s) are required to absorb drug at an efficiency which protect the patient's systemic circulation from toxic side effects of high drug concentrations. During use with certain drugs such as Melphalan Hydrochloride, poor filtration can cause side effects such as anemia, thrombocytopenia, neutropenia, together commonly known as Myelo Suppression. Other drugs at high concentrations have risk of cardio toxicities if poor filtration fails to reduce systemic concentrations to safe levels. [0004] Filters, pumps, and connecting tubing are typically set up and assembled by a perfusionist, or other technician, prior to the case. Filters may be clamped or taped to equipment such as IV poles. Multiple filters are often used to aid efficiency. Many times hardware such as lab clamps can become misplaced between cases wasting time to find or forcing the technician to improvise a support method at the last minute. [0005] The system, including filters, is connected to catheters for withdrawal and return of blood to the patient. For the entire system all surfaces exposed to body fluids should be kept sterile. [0006] Prior to use, the filters, blood circuit tube set, and pump are prepared for the procedure. The filters are required to be primed with saline to remove all air from the filter media and to be flushed with saline to remove any fine particulate in the media prior to blood being introduced to the circuit. Proper priming is critical to filter performance. Removing air is necessary to eliminate the potential for air to be infused into the patient. Also, any air left in the filter reduces the surface area that blood will contact the filter media thus reducing filter efficiency. SUMMARY [0007] The inventors have recognized some problems with prior art filters and provide herein an apparatus that can solve many of the problems in the prior art. [0008] Where multiple filters are used, the set up procedure can become cumbersome and unsteady. Technicians will need to use a variety of hardware to clamp the filters to a support. [0009] If filters were to fall, sterility could be comprised, or catheters could be dislodged from the patient's body. Additionally, filters could crack or leak exposing technical staff and equipment to high concentrations of toxic compounds such as chemotherapeutic drugs. [0010] If the filters are clamped in place to a support or taped together, it may be difficult to see the entire filter's circumference and this will hinder the priming process where air bubbles are to be removed. Additionally, if a technician attempts to turn the filters to visualize the circumference, the mounting method may need to be repeated. [0011] Additionally, during use filters may not see the same resistance to flow if they are angled or set at different heights relative to each other. In accordance with an advantageous feature of some embodiments of the invention, the filters are held in about the same orientation. This will enable about the same flow resistance in each filter such that blood flows about equally through each filter. When filtering drugs from blood it is desirable that each filter provides the same flow resistance so that blood equally flows through each filter. A reduction in flow in one filter may allow thrombus formation in the low flow filter which can continue to develop until flow is completely stopped in that filter. The other filter then provides for the majority, and possibly 100% of the flow and filtration. If the flow rate remains the same, and the total filter volume is decreased or possibly reduced by 50%, the residence time will decrease thus reducing filter efficiency. Additionally, having all flow forced through only one filter may lead to complete saturation of the filter media and limit the filters ability to absorb or filter drug from the blood. Reduced filter efficiency may lead to an increase in adverse reactions caused by the toxic effects of the chemotherapeutic drug not adsorbed by the filter. [0012] The inventors recognized that that these problems could be solved by providing, in some embodiments of the invention, a filter system, apparatus, and method which allows the technician to quickly and securely attach the filter housing to a support without the need for additional hardware. Filter cartridges can be easier to prime and verify all air is removed if the housing allows the cartridges to be rotated so that all areas of the filter can be visualized. The system will guarantee that filters have the same flow conditions if the housing mounts all filter cartridges at the same height and orientation. Combining filter cartridges in a rugged frame housing will increase durability of the product. In some embodiments of the invention, provided herein is a filter system and apparatus wherein the housing of the apparatus enables the filter cartridges to be rotated so that all areas of the filter can be visualized, the housing mounts all of the filter cartridges at the same height and orientation, and the filter cartridges are combined in a rugged frame housing that provides durability. The combination of these features results in an easy to use and robust filter system that protects the equipment and staff from inadvertent breakage. The apparatus allows for the holding of filter cartridges in about the same orientation. The filter cartridges being held in about the same orientation allows for the flow to be about the same in the different cartridges. [0013] In some embodiments, the invention is a filter system where multiple filter cartridges are mounted in a single frame housing. The housing includes a built in clamping mechanism that deploys to allow the filter to be mounted to an IV pole or other suitable and available structure in an operating room. A technician can simply open the sterile supplied filter system, deploy the mounting mechanism, and clamp the assembly to an available IV pole or other supporting member available in the operating room. The housing is mechanically strong and provides a very solid attachment to the support with no risk of falling and no need to improvise a clamping means. The cartridge is allowed to rotate within the housing during priming so that all areas of the filter can be visualized to verify air has been removed. The housing also insures that both filters are mounted in the same orientation and height which guarantees that each filter sees the same flow conditions. [0014] In some embodiments, provided is a filter apparatus, comprising two or more filter cartridges having a first end with an inlet and screen and a second end with an outlet and screen, and walls to contain a filter media, a housing for holding the two or more filter cartridges in about the same orientation, and an attachment clamp connected to the housing. In some embodiments the housing comprises an upper plate and a lower plate for holding the two or more filter cartridges, the upper plate and the lower plate comprising openings for rotatably engaging the two or more filter cartridges, and one or more support elements connecting the upper plate and the lower plate. By providing for the rotation of the filter cartridges, a medical professional can examine the filter media in the where the cartridges are made of a transparent material. Examination of the filter media is often useful in various stages of medical procedures that comprise filtration such as when the filter media needs to be primed for filtration. Priming often comprises removal of trapped gas bubbles in the filter media and being able to notice whether bubbles are trapped in the filter media will help facilitate the priming process. [0015] In some embodiments of the filter apparatus, the attachment clamp is connected to one or more of the one or more support elements. In some embodiments, the one or more support elements comprise a combination of rods and support plates. In some embodiments the attachment clamp is a pole clamp. [0016] In some embodiments of the filter apparatus the walls that contain the filter media comprise a cartridge tube. In some embodiments, the cartridge tube is transparent. [0017] In some embodiments of the filter apparatus the inlet and outlet comprise an inlet connector and an outlet connector. In some embodiments, the outlet connector is connected to the cartridge tube by an outlet flange. In some embodiments, the outlet flange is conical. [0018] In some embodiments, the inlet connector is connected to the cartridge tube by an inlet flange. [0019] In some embodiments of the filter apparatus, the filter media comprises activated carbon. In some embodiments, the filter media is hydrogel coated activated carbon. [0020] In some embodiments of the filter apparatus, the walls to contain the filter media define a cylindrical shape. [0021] In some embodiments, provided is a filter apparatus, comprising two filter cartridges having a first end with an inlet comprising an inlet connector connected to the cartridge tube by an inlet flange and screen and a second end with an outlet comprising an outlet connector and connected to the cartridge by a conical outlet flange and screen, and a transparent cartridge tube to contain a filter media, a housing for holding the two filter cartridges in about the same orientation comprising an upper plate and a lower plate for holding the two filter cartridges, the upper plate and the lower plate comprising openings for rotatably engaging the two filter cartridges, support elements comprising support plates and rods connecting the upper plat to the lower plate, and a pole clamp connected to the support plates. [0022] In some embodiments, the filter apparatus the cartridge tubes of the filter apparatus are comprised of a transparent material selected from a polysulfone, a polycarbonate, a polypropylene, an acrylic, or combinations thereof. [0023] In some embodiments, provided is a housing for holding two or more filter cartridges in about the same orientation, comprising a connected structure comprising an upper plate and a lower plate, the upper plate and the lower plate comprising openings for rotatably engaging the two or more filter cartridges, one or more support elements connecting the upper plate and the lower plate, and an attachment clamp connected to the housing. [0024] In some embodiments, a method is provided for setting up a filter apparatus for a hemo filtration therapy, comprising attaching a filter apparatus according to claim 1 to an IV pole and rotating the cartridges to observe if there are lodged bubbles in the filter media. In some embodiments of the method, the housing is a connected structure. BRIEF DESCRIPTION OF THE DRAWINGS [0025] FIG. 1 shows a perspective view from the front of dual filter cartridges mounted in a single frame; [0026] FIG. 2 shows a top view of dual filter cartridges mounted in a single frame with the mounting means deployed for connection; [0027] FIG. 3 shows a bottom view of dual filter cartridges mounted in a single frame with the mounting means deployed for connection; [0028] FIG. 4 shows a front view of dual filter cartridges mounted in a single frame; [0029] FIG. 5 shows a perspective view from the back of dual filter cartridges mounted in a single frame with mounting means stowed for packaging; [0030] FIG. 6 shows a back view of dual filter cartridges mounted in a single frame with mounting means stowed for packaging; [0031] FIG. 7 shows a side view of dual filter cartridges mounted in a single frame with the mounting means deployed for connection; [0032] FIG. 8 shows an exploded view of dual filter cartridges and housing; [0033] FIG. 9 shows a perspective view from back of dual filter cartridges mounted in a single frame with mounting means deployed and connected to a pole such as an IV pole; and [0034] FIG. 10 shows dual filter cartridges mounted in a single frame in an extracorporeal blood filtration set up incorporated into a percutaneous hepatic perfusion procedure. DETAILED DESCRIPTION [0035] In some embodiments, a filter cartridge can be made in the following way by assembling lower inlet flange 12 to the cartridge tube 11 , to the upper outlet flange 18 . An inlet connector 15 is connected to lower inlet flange 12 . In some embodiments, an inlet screen (not shown) is incorporated at the inside end of a cartridge tube 11 at the joint between the lower inlet flange 12 and cartridge tube 11 . In some embodiments, filter media can be added to the assembly by filling the inside volume of cartridge tube 11 . An outlet connector 19 is connected to upper outlet flange 18 . An outlet screen (not shown) is incorporated at the inside ends of cartridge tube 11 at the joint between the upper outlet flange 18 and cartridge tube 11 . The screens provide a means to keep filter media (not shown), typically small spheres or beads, within the filter cartridge while allowing blood to flow into, through, and out of the filter. The screens can be formed of a suitable polymer with a 200-400 micron mesh. The flanges 12 and 18 and tube 11 can be formed from any suitable transparent plastic such as a polysulfone, a polycarbonate, a polypropylene, an acrylic, and the like. In some embodiments, combinations of these transparent materials can be used. The connections between components can be joints formed by adhesive such as two part epoxy or ultraviolet light curing epoxy, or the joints can be heat welded by means such as radio frequency welding, induction welding, or ultrasonic welding. [0036] The housing is assembled from structural components. In some embodiments, lower plate 1 is attached to six tie rods 7 with six tamper proof flat head cap screws 10 . In some embodiments, center support plates 2 and 3 are assembled with the pole clamp 5 to create a deployable mounting mechanism. Pivot pin 4 is pressed fit into center support plate 2 , and is passed through pole clamp 5 and is press fit into opposite center support plate 3 . Three stop pins 6 are pressed into receiving holes in center support plate 2 and 3 . Two stop pins 6 form the stop for the pole clamp 5 deployed position, one stop pin 6 form the stop for the stowed position. Clamp knob 8 has a threaded shaft that is screwed through pole clamp 5 . The sub assembly of center support plates 2 and 3 , pins 4 and 6 , and pole clamp 5 and knob 8 creates the deployable mounting mechanism. The sub assembly is then attached to lower plate 1 with four tamper proof flat head cap screws 10 . Herein, item 1 is used for both upper plate and lower plate as the plates are the same part. Face plate 25 is inserted into grooves in the center support plates 2 and 3 and slid towards the lower plate 1 until it contacts the lower plate 1 . O ring 9 can be formed from an elastomeric material such as Silicone or Viton. One O ring 9 is added to the top of each cartridge assembly at the upper outlet flange 18 . A cartridge assembly with O ring 9 is inserted into each side of the frame housing between tie rods 7 and center support plates 2 and 3 . Upper plate 1 is placed on top of the assembly and secured to the tie rods 7 and center support plates 2 and 3 with ten tamper proof flat head cap screws 10 . The O rings 9 are captured between upper plate 1 and upper outlet flanges 18 such that the cartridges can smoothly rotate within the housing frame without being loose or creating excessive compression of the cartridge within the housing frame. [0037] In some embodiments of the invention, the filter system can be packaged, labeled, and sterilized by the manufacturer. It can be shipped to the customer alone or as a component of a comprehensive kit containing all components needed to perform a procedure. Once in use the technician setting up the system will open the packaging while maintaining sterility of inlet connector 15 and outlet connector 19 . As shown in FIG. 9 , the pole clamp 5 can be deployed from its storage position between center support plates 2 and 3 . The pole clamp 5 can rotate around pivot pin 4 and contact stop pins 6 , which limits the clamp rotation to a perpendicular orientation. The pole clamp 5 can be placed around an available IV pole or similar available structure in the operating room. The frame is secured to a pole by tightening clamp knob 8 on to the pole. [0038] The technician and physician team can then assemble the system connect tubing between the filter system and other components which make up a complete circuit such as pump, saline supply bags, and flow rate monitor. The tube set which connects to the filter uses rotatable connectors to connect to inlet connectors 15 and outlet connector 19 . All components are primed and flushed with saline. The technician will slowly fill the filters with saline from the bottom up allowing air to escape from the top. Due to the high surface area of some filter media, air will often be trapped in the filter cartridge and will need to be coaxed to leave by slowly flushing saline through the filter while tapping the filter cartridge walls to break the air bubbles free. To insure that all air has been removed the technician can rotate the cartridge within the frame to view the entire circumference of the cartridge. Once the filters are primed, the final connections can be made to the isolation aspiration catheter which acts as a supply catheter and the venous return catheter, already placed in location in the patient as shown in FIG. 10 . The procedure can then be performed with a secure and safe system.

Provided is a filter apparatus, comprising two or more filter cartridges having a first end with an inlet and screen and a second end with an outlet and screen, and walls to contain a filter media held in a housing for holding the two or more filter cartridges in about the same orientation, and an attachment clamp connected to the housing. Also provided is a housing for holding two or more filter cartridges in about the same orientation and a method of using the filter apparatus and housing.

TECHNICAL FIELD OF THE INVENTION This invention relates to a terminal strip for making terminals and more particularly to terminals having a compliant portion and to a method for making such. BACKGROUND OF THE INVENTION A terminal is known to electrically interconnect one electrical component to another through a pressure fitted electrical connection at either or both ends. The terminal is typically made of a cost effective tin plated copper alloy providing a reliable electrical connection. When making or breaking the electrical connection, the tin oxide layer of the terminal essentially cracks permitting clean tin to ooze out through the crack. The clean tin bonds to the connector of the electrical component providing a very stable electrical connection Fretting corrosion is a known phenomenon which can cause otherwise stable tin plated copper alloy electrical connections to fail. For fretting corrosion to occur, there must be a small degree of movement or rubbing between the pressure fitted tin plated terminal interface. Such movement is usually the result of vibration from one or both of the electrical components. Fretting or the rubbing of the terminal interface together typically occurs only when the vibration or displacement between components is of a small magnitude measured in microns (i.e. 10-100 microns) and the pressure between the interface is low. Fretting corrosion occurs when the once clean tin is exposed to the air as a result of movement, wherein the tin quickly forms into an electrically insulating tin oxide film. With repeated motions, the debris of tin oxide builds up until the electrical connection fails. Fretting corrosion can be eliminated by preventing the electrical components from vibrating, or utilizing gold or silver based terminal contact coatings which resist fretting corrosion. Unfortunately, either means may not be practical or may be cost prohibited depending upon the application. SUMMARY OF THE INVENTION The present invention provides an elongated terminal strip having a series of terminals and Cut lines disposed therebetween. Each terminal has a compliant portion extending longitudinally with respect to the elongated terminal strip from one laterally extended cut line to the next succeeding cut line. An electrical contact first portion extends laterally outward from the compliant portion between the two adjacent cut lines. An opposing second portion, extends laterally outward from the opposite side of the compliant portion. The first and second portions electrically engage respective electrical components. If either electrical component should vibrate, the compliant portion of the terminal will extend, retract or twist, in other words, will move within a three dimensional array, thereby enabling either the first or second portions of the terminal to move relative to the respective vibrating electrical component preventing any relative movement at the electrical contact points and eliminating fretting concerns. The compliant portion has at least one slot which extends longitudinally with respect to the elongated terminal strip from either one of the adjacent cut lines to an end of the slot disposed within the compliant portion of the terminal. Preferably, the compliant portions have a plurality of slots which extend from both of the adjacent cut lines. For instance, preferably the compliant portion has a leading slot extended rearward within the compliant portion. The leading slot is disposed between two trailing slot which extend forward within the compliant portion from a succeeding cut line to the cut line communicating with the leading slot. The trailing slots have ends disposed within the compliant portion lying slightly rearward of the cut line communicating with the leading slot. The ends of the trailing slots are disposed laterally outward with respect to the leading slot. A feature of the present invention is the reduction of fretting corrosion caused by vibrating electrical components. Another feature of the invention is the production of a cost effective and robust compliant portion of the terminal. BRIEF DESCRIPTION OF THE DRAWINGS The presently preferred embodiments of the invention are disclosed in the following description and accompanying drawings wherein: FIG. 1 is a partially exploded perspective view of a terminal strip of the present invention, FIG. 2 is a partially exploded perspective view of a second embodiment of a terminal strip of the present invention; and FIG. 3 is partially exploded perspective view of a third embodiment of a terminal strip of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a terminal strip 10 of the present invention has a series of terminals 12 generally aligned laterally across the longitude of the terminal strip 10 . A substantially planar compliant portion 14 is engaged between an electrical contact first portion 16 and an electrical contact second portion 18 . The compliant portion 14 extends longitudinally with respect to the elongated terminal strip 10 in a forward direction from a trailing cut line 20 to a leading cut line 22 . The compliant portion 14 of the terminal 12 is substantially identical to the next succeeding compliant portion 14 of the next terminal 12 along the terminal strip 10 . Interconnecting each terminal 12 along the terminal strip 10 are a series of connecting portions 24 . Each connecting portion 24 extends rearward from the trailing cut line 20 of one terminal 12 to the leading cut line 22 of the next succeeding terminal 12 . The connecting portion 24 has an indexing hole 26 which receives a protrusion from a manufacturing cutting machine (not shown) to align the terminal strip 10 prior to cutting the terminal 12 off from the terminal strip 10 along the trailing and leading cut lines 20 , 22 . After the terminals 12 are formed and cut, the cut connecting portion 24 becomes scrap material. Providing the flexibility within the compliant portion 14 of the terminal 12 is a leading slot 28 . Leading slot 28 extends rearward from the leading cut line 22 and longitudinally with respect to the terminal strip 10 . The leading slot 28 has an end 30 disposed within the compliant portion 14 slightly forward of the trailing cut line 20 and an opposite end 32 disposed either on the leading cut line 22 or slightly within the connecting portion 24 disposed adjacent to and forward of the compliant portion 14 . Providing additional flexibility of the compliant portion 14 are preferably two longitudinally extended tailing slots 34 . The trailing slots 34 extend forward from the trailing cut line 20 and longitudinally with respect to the terminal strip 10 . Each trailing slot 34 has an end 36 disposed within the compliant portion 14 slightly rearward of the leading cut line 22 and an opposite end 38 disposed either on the trailing cut line 20 or slightly within the connecting portion 24 disposed adjacent and rearward of the compliant portion 14 . A major portion of the leading slot 28 contained within the compliant portion 14 is disposed substantially between the two trailing slots 34 . The two ends 36 of the trailing slots 34 are disposed laterally outward from and on either side of the leading slot 28 . The leading slot 28 and the trailing slots 34 are substantially parallel to one another. The configuration of the leading and trailing slots 28 , 34 provide a three dimensional flexing capability of the compliant portion 14 . In other words, the electrical contact first portion 16 may move toward or away from the contact second portion 18 of the terminal 12 as a result of electrical component vibrations. Similarly, the first and second portions 16 , 18 may twist, move side to side, or move up and down with respect to one another. This flexibility of the compliant portion 14 ensures that the electrical contact points of the first or second portions 16 , 18 and the respective electrical components do not rub as a result of component vibration. In this way, fretting, corrosion is avoided or at least reduced. Increasing the number of alternating trailing and leading slots 34 , 28 , or increasing the lengths of the slots within the compliant portion 14 can further enhance the flexing capability of the terminal 12 if the need is required. During the manufacturing process, the terminal strip 10 is pre-stamped, containing all of the leading and trailing slots 28 , 34 and indexing holes 26 previously described. The step of cutting the connecting portion 24 away from the leading end of the terminal strip 10 , along the leading cut line 22 , cuts off the opposite end 32 of the leading slot 28 exposing the leading slot 28 along the cut edge of the compliant portion 14 , as shown in FIG. 1 . Likewise, the step of cutting the terminal 12 away from the subsequent leading end of the terminal strip 10 , along the trailing cut line 20 leaves the opposite ends 38 of the trailing slots 34 behind within the next succeeding connecting portion 24 of the terminal strip 10 . The trailing slots 34 of the separated terminal 12 are now exposed through the opposite cut edge of the compliant portion 14 . In essence, the act of cutting or dispensing the terminals 12 from the terminal strip 10 creates or enables the flexibility of the compliant portion 14 . Referring, to FIG. 2, a second embodiment of the present invention is illustrated wherein the connecting portions 24 of the first embodiment are eliminated so that the compliant portions 14 ′ of the terminals 12 ′ are end to end or juxtaposed. The terminal strip 10 ′ of the second embodiment is indexed within the manufacturing cutting machine utilizing any one of the trailing or leading slots 34 ′, 28 ′ as the indexing hole 26 of the first embodiment. The trailing cut line 20 and the next succeeding or trailing, cut line 22 of the first embodiment coincide in the terminal strip 10 ′ of the second embodiment, forming a singular common cut line 40 . The terminal 12 ′ extends from cut line 40 to the next succeeding common cut line 40 . The leading slot 28 ′ extends rearward from the cut line 40 into the compliant portion 14 ′. The trailing slots 34 ′ extend forward from the next succeeding common cut line 40 . The leading and trailing slots 28 ′, 34 ′ have the same configuration within the compliant portion 14 ′ as previously described for the terminal strip 10 of the first embodiment. Referring to FIG. 3, a third embodiment of the present invention is shown. Unlike the first and second embodiments where the terminals 12 or 12 ′ are identical, the series of terminals 12 ″ of the terminal strip 10 ″ comprise alternating leading and trailing terminals 42 , 44 . Although not identical to one another as are the terminals 12 ′ of the second embodiment, the leading terminal 42 of the third embodiment is substantially a mirror image of the trailing terminal 44 . The leading terminal 42 extends rearward along the terminal strip 10 ″ from a second cut line 48 to a first cut line 46 . The trailing terminal 44 is disposed adjacent to the leading terminal 42 and extends rearward from the first cut lie 46 to the next succeeding second cut line 48 . The leading terminal 42 has a trailing slot 50 which extends forward from the first cut line 46 to an end 52 . The end 52 of the trailing slot 50 is disposed within the compliant portion 54 slightly rearward of the respective second cut line 48 . The leading terminal 42 preferably has two leading slots 56 disposed on either side of the trailing slot 50 . The leading slots 56 extend rearward from the second cut line 48 to respective ends 58 . The end 58 is disposed within the compliant portion 54 slightly forward of the first cut line 46 and laterally outward with respect to the trailing slot 50 . The trailing terminal 44 has the leading slot 28 ″ extending rearward within the compliant portion 14 ″ from the first cut line 46 to the end 30 ″. The end 30 ″ is disposed within the compliant portion 14 ″ slightly forward of the second cut line 48 . Furthermore the leading slot 28 ″ of the trailing terminal 44 is collinear to the trailing slot 50 of the leading terminal 42 and communicates with the trailing slot 50 through the first cut line 46 . The trailing terminal 44 also has preferably two trailing slots 34 ″ which extend forward from the second cut line 48 within the compliant portion 14 ″ to the end 36 ″ which is disposed slightly rearward from the first cut line 46 . Like the first and second embodiments, the leading slot 28 ″ is disposed substantially between the two trailing slots 34 ″. The ends 36 ″ of the trailing slots 34 ″ are disposed laterally outward with respect to the leading slot 28 ″. Each respective trailing slots 34 ″ of the trailing terminal 34 are collinear with the respective leading slots 56 of the leading terminal 42 and thereby communicate through the second cut line 48 . Although the preferred embodiment of the present invention have been disclosed, various changes and modification may be made thereto by one skilled in the art without departing from the scope and spirit of the invention as set forth in the appended claims. Furthermore, it is understood that the terms used herein are merely descriptive, rather than limiting and various changes may be made without departing from the scope and spirit of the invention.

An elongated terminal strip has a series of terminals, each having a compliant portion engaged laterally between a first and second portion which electrically engage to respective electrical components having a tendency to vibrate. Each compliant portion extends longitudinally with respect to the terminal strip between two adjacent cut lines. A plurality of leading and trailing slots extend longitudinally within the compliant portions and are disposed alternately through one then the other adjacent cut lines. The step of dispensing or cutting the terminal away from the terminal strip exposes the slots along the cut edge enabling the flexing capability of the compliant portion.

BACKGROUND OF THE INVENTION [0001] I. Field of the Invention [0002] The present invention relates to soft plastic tube-type fishing lure. More specifically, the present invention relates to improvements to tube-type fishing lures concerning their ability to attract fish and their ability to securely hook a fish that bites the bait. [0003] II. Description of the Prior Art [0004] Tube baits generally consist of a soft plastic tube surrounding a cavity and having a generally closed end and an open end. A plurality of plastic tentacles extends from the open end of the tube. Tube baits also include a hook. The hook has an eye, point, barb, shank and bend creating a gap between the shank and the barb typically, a single hook with a wide gap is used with tube baits. The shaft sometimes exits the open end of the tube such that the curve positions the barb parallel to the center axis of the body of the tube. Alternatively, the user can push the point of the hook through the soft body of the tube and positions the barb of the hook outside of the tube and generally parallel to the center axis of the body of the tube. In either case, the eye (and sometimes a portion of the shank) is pushed through the closed end of the tube. Sometimes a weight is also attached to the shank of the hook outside the tube between the eye of the hook and the front closed end of the tube. However, such a weight can result in an unnatural appearance. [0005] Prior art tube baits have proven to be effective when used by experienced professional anglers. However, amateurs and inexperienced anglers have difficulty catching fish with such baits. Some of the problems inexperienced anglers encounter relate to their inability to get the tube bait to mimic the patterns real minnows and crawfish display. Minnows, for example, tend to drift down through the water without their heads pointing either up or down. If the weight distribution of a tube bait is such that either end of the tube points down as it falls through the water, the tube bait will look unnatural to fish in the area. Likewise, if the angler does not provide enough slack in the line, the closed end will point up as the tube bait drifts down presenting an unnatural appearance. [0006] Inexperienced anglers also have problems setting the hook of prior art tube baits. If the hook is not set so it penetrates both soft tissue and one of the bones of the mouth of the fish, large fish or those that put up a fight easily can escape. SUMMARY OF THE INVENTION [0007] The present invention addresses each of the problems with prior art tube baits outlined above. To provide a more natural presentation of the tube bait to fish in the area, a unique and distributed weighting mechanism is provided. To reduce problems associated with setting the hook, the hook having a single point used in the prior art is replaced by a hook having a plurality of points and barbs is used. [0008] The construction of the improved tube bait of the present invention will be better understood from the following detailed description of the preferred embodiment with specific reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is a perspective view of a prior art tube bait. [0010] FIG. 2 is a cross-sectional view of the tube bait of FIG. 1 through line 2 - 2 . [0011] FIG. 3 is a perspective view of the tube bait of the present invention. [0012] FIG. 4 is a cross-sectional view of the tube bait through line 3 - 3 of FIG. 2 showing a first embodiment of the tube bait of the present invention. [0013] FIG. 5 is a cross-sectional view of the tube bait through line 3 - 3 of FIG. 3 showing a second embodiment of the present invention. [0014] FIG. 6 is a cross-sectional view of the tube bait through line 303 of FIG. 2 showing a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0015] As shown in FIGS. 1 and 2 , prior art tube baits 1 typically comprise a tube 2 having a soft plastic wall 3 surrounding a hollow chamber 4 . The wall 3 has a front closed end 5 and an open rear end 6 . Projecting rearwardly from the tube 2 and attached to the rear end 6 of the tube 2 is a number of soft, flexible plastic tentacles 7 . The tube is generally hollow and has a central axis 8 . The tube bait 1 also has a hook 10 . The hook 10 is generally J-shaped and includes an eye 11 for attaching the hook 10 to a fishing line, a shank 12 extending from the eye 11 to a curve 13 and a barb 14 extending from the curve 13 to a point 15 . The major portion of the shank 12 is positioned inside the hollow chamber 4 . The shank 12 penetrates the front closed end 5 of the tube 2 to expose the eye 11 . The curve 13 penetrates wall 3 of tube 2 intermediate the front end 5 and rear end 6 of the tube 2 . Thus, the barb 14 and point 15 of the hook reside outside of the tube 2 . The barb 14 is generally parallel to the central axis 8 of the tube 2 . FIG. 1 also shows an exterior weight 16 attached to the shank 12 of the hook 10 between the eye 11 of the hook and the front end 5 of the tube 2 . The eye 11 is used to attach the tube bait to a fishing line (not shown) in a conventional manner. [0016] The positioning of the weight 16 in FIG. 1 typically causes the tube bait 1 to tip with the weight down as the tube bait descends through the water resulting in an unnatural presentation. Also, the single barb 14 and point 15 of the hook 10 makes the typical tube bait difficult to set when a fish bites or nibbles on the tube bait. The wide gap and exposed barb 14 and point 15 of the hook also result in an unnatural appearance. These problems are all overcome by the embodiments of the present invention disclosed in FIGS. 3-6 . [0017] The embodiments of FIGS. 3-6 still all comprise a soft plastic tube 2 having a wall 3 terminating in a front end 5 and a rear end 6 . The front end 5 is typically closed while the rear end 5 is open to the hollow chamber 4 of the tube 2 . Attached to and extending away from the rear end 6 of the tube 2 is a plurality of tentacles 7 . However, each of the four embodiments shown in FIGS. 3-6 show important improvements over prior art tube baits. [0018] FIGS. 3-6 each show a leader 20 and a treble hook 30 . FIGS. 4-7 also each show an interior weighting mechanism 40 . However, as described below the interior weighting mechanism 40 shown in each of FIGS. 4-6 is different. [0019] The leader 20 shown in each of FIGS. 3-6 comprises a shaft 21 made of a length of wire with eyelets 22 and 23 formed at each end of the leader 20 . When used, the eyelet 22 is used to attach the tube bait to a fishing line (not shown) in any conventional manner. The eyelet 23 is used to attach the treble hook 30 to the leader 20 . In the drawings, such attachment is made using a coupling ring 24 . However, other conventional means can also be used to attach the hook 30 to the leader 20 without deviating from the invention. The length of the shaft 21 may be adjusted depending on the composition of the interior weighting mechanism used. [0020] As shown, treble hook 30 comprises an eye 31 , a shank 32 , three J-shaped curves ( 33 a , 33 b and 33 c ) and three barbs ( 34 a , 34 b and 34 c ) each terminating in a point ( 35 a , 35 b and 35 c ). The shank 32 can, of course, be three separate shanks fused or otherwise joined together. Eye 31 is used to join the hook 30 to the leader 20 . While a treble hook 30 is shown in the drawings, what is important is that the hook presents a plurality of barbs and points as opposed to a single barb and point. Thus, any hook with two or more barbs and points may suffice. The advantage of using a hook with multiple barbs such as treble hook 30 is that the hook will more securely set in either the soft tissue or bone of the fish at multiple points as opposed to a single point. [0021] The various interior weighting mechanisms 40 shown in FIGS. 3-6 provide various advantages related to the speed of the tube bait 1 as it drops through the water and the presentation of the tube bait 1 as it descends through the water. As shown in FIGS. 3-6 , the interior weighting mechanism 40 resides within the hollow interior chamber 4 of tube 2 and about the shaft 21 of the leader 20 . In FIG. 3 , the interior weighting mechanism 40 includes a plurality of spherical weights 41 of differing sizes and/or densities. Each spherical weight 41 has a bore sized to permit the shaft 21 to pass through the weight 41 . The distribution of weights of different sizes or densities along the shaft 21 allows for control of the presentation of the tube bait during descent. Specifically, the distribution of the weights of different diameters or densities along shaft 21 can be used to ensure that the tube bait drifts down without either end tipping markedly downward or upward relative to the other. Of course, the correct distribution of smaller and larger weights 41 along the shaft 21 will be dependent on the characteristics of the plastic tube 2 and tentacles 7 . Also, if the weights 41 are not packed too tight on the shaft 21 , some rattling of the weights will occur which also serves to attract fish. The weighting mechanism 40 could also include a time release capsule filled with a scent that either attracts fish or masks the human scent of the angler which may have transferred to the tube bait 1 . [0022] The plastic used to form the tube 2 and tentacles 7 may be sufficiently dense to cause the tube bait to sink on its own without adding weights 41 . Even when this is the case, it may be desirable to control the rate of descent or to prevent the ends of the tube 2 from pointing up or down as the tube bait 1 descends. Such control is provided in the embodiment of FIG. 5 by replacing the spherical weights 41 with one or more low density internal floats 51 . Such floats may be of different sizes and densities like the weights 41 . Each will typically have a bore therethrough so the floats 51 can be arranged on the shaft 21 of the leader 20 and within the hollow chamber 4 of tube 2 . Proper arrangement of floats 42 on the shaft 21 will again depend on the composition of the tube 2 and tentacles 7 . They should be arranged to provide generally level descent at the proper rate. In FIG. 6 , a combination of floats 42 and weights 41 are arranged on the shaft 21 and within the hollow chamber 4 to provide such level descent at the proper rate. [0023] The various embodiments shown in FIGS. 3-6 provide important advantages over the prior art. First, the overall appearance is more realistic. There is no large weight at the front as in FIG. 1 . Instead, the weights 41 (and/or floats 42 ) are all located within the hollow chamber 4 of the tube 2 . Further, there is no large hook projecting through the side of the tube 2 as shown in FIG. 1 . Instead, the barbs 34 a , 34 b and 34 c of the treble hook 30 are all to a very large extent camouflaged by the tentacles 7 . [0024] Second, the presentation of the tube bait as it drifts down through the water is more lifelike since the interior weighting mechanism 40 (i.e., the weights 41 and floats 42 ) provide not only a proper rate of descent, but also substantially eliminate tipping of the tube as it slowly drops through the water. Locating the weights and floats inside the hollow chamber of the tube bait also results in a more natural appearance. [0025] Third, the hook 30 of the present invention provides multiple potential points of contact between the mouth of the fish and the hook. Catching soft tissue with more than one point and barb is typically enough to prevent the fish from escaping the hook even if bone is not penetrated by any of the barbs and points. [0026] Those skilled in the art will recognize from the foregoing disclosure that the present invention provides important advantages over the prior art. Those skilled in the art will also appreciate that modifications can also be made without deviating from the present invention. Thus, the foregoing description is intended to meet the disclosure requirements of the patent laws without being limiting.

An improved lure for use when fishing provides better control of the lure by novice and experienced fishermen, better camouflage of the hook and weighting system associated with the lure and more secure setting of the hook when a fish bites. The improved lure comprises a standard tube bait in combination with a hook and weighting arrangement that makes the lure easier to use than prior art tube baits.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of our copending application, Ser. No. 08/045,515, filed Aug. 9, 1993, still pending all of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION Wave guides have become familiar means to transmit high radio frequency signals, especially in the microwave region. More recent developments have made wave guides for the transmission of light rather commonplace. An optical fiber is a wave guide in which light is propagated by total internal reflection at the fiber boundaries. For the purpose of this application, "light" will refer to electromagnetic radiation in the ultraviolet, visible, and infrared ranges of the electromagnetic spectrum, which are approximately 200-400 nm, 400-800 nm, and 800-300,000 nm, respectively, extending through the far infrared range. The greatest use of optical fibers has been in communication and data transmission systems where light waves of a narrow wavelength are used as carriers via pulse or frequency modulation to transmit information. A less common but increasingly important application of optical fibers is for the transmission of analog information from a sensor to a remotely located detector which measures the intensity of the transmitted light over a range of wavelengths within the spectrum of light. For the purpose of this application the spectral range of greatest interest is that spanning the ultraviolet (ca. 200-400 nm), visible (ca. 400-800 nm) and near infrared (ca. 800-2500 nm). The measurement of, for example, digital information differs significantly from that of analog information and imposes different requirements. Where digital information is transmitted along an optical fiber one is interested only in whether or not a signal is present, or more accurately whether light of a particular frequency is present at an intensity above some threshold value. Where analog information is transmitted along optical fibers one is interested in the absolute intensity of the signal at each wavelength of some extended portion of the light spectrum. Thus it becomes clear that where accurate transmission of analog information along an optical fiber is required it is necessary that both the wavelength and intensity of the transmitted light be preserved, that is, one can tolerate neither wavelength shifts nor intensity variation along the transmission path. The principles of optical fibers are too well known to require extended discussion here. See, for example, "Optical Fiber Communications", B. K. Tariyal and A. H. Cherin, Encyclopedia of Physical Science and Technology, Vol. 9, pp 605-629 (1987); "Optical Fibers, Drawing and Coating", L. L. Blyler, Jr. and F. V. DiMarcello, ibid., pp 647-57. In brief, optical fibers have a core of plastic, glass, silica or other glassy transparent material with an outer, concentric layer called cladding which has a refractive index lower than the core. Where light injected into the core strikes the core-cladding interface at an angle of incidence greater than the critical angle there is total reflection, and since the angle of incidence equals the angle of reflection it follows that light will zigzag or spiral along the length of the core. Although in theory there should be no light loss, in practice attenuation occurs along the optical fiber because of the absorption by impurities within the core and because of scattering arising mainly from fiber imperfections such as non-uniform core diameter, bends in the fiber, and discontinuities at the core-cladding interface. Optical fibers per se are delicate and fragile, and generally need to be protected by being sheathed with several concentric layers. In a variant of interest here the core of the optical fiber is coated during the drawing process with a thin layer of a tough polymer, such as a polyimide, to protect the delicate surface from scratching and marring, and to prevent microfracture. This is followed by another concentric layer of an elastic polymer, such as silicones, thermoplastic rubber compounds, urethanes or acrylates. Yet other coatings may be applied as protection from physical and chemical damage. It also should be noted that in another variant the cladding itself may be an elastic polymer. Of special interest is the case where the optical fiber comprises concentric layers of a glassy core of refractive index n, a glassy cladding of refractive index less than n, a polyimide coating, and a silicone coating. It needs to be emphasized that even though such an optical fiber is of special interest to us, our invention is not limited to such an optical fiber but is instead applicable to optical fibers generally. We recently observed spurious signals in light transmitted along optical fibers under two quite different circumstances. In one case the intensity of light transmission varied with the intensity of ambient light external to the optical fiber. Thus, the light intensity measured at different wavelengths at the exit of an optical fiber varied with the intensity of external light. This implied that there was a significant amount of extraneous light from a source external to the fiber entering the core through the cladding along the length of the optical fiber, contrary to expectations. By "extraneous light" is meant light inserted into the core of an optical fiber through the cladding, in contradistinction to light injected directly into the core. The second circumstance of spurious light transmission was noticed in an optical fiber having bends along its length and was manifested as selective attenuation at certain wavelengths. Further investigation showed that the wavelengths whose intensity were reduced corresponded to spectral absorption bands of a coating for the fiber. Evidently light was not totally reflected at the core-cladding interface at bends in the fiber but was reflected at the surface of other coatings acting as a secondary cladding. Thus light traversed the core-(primary)cladding interface, through one or more coatings external to the primary cladding where selective absorption occurred, was reflected at the interface with the secondary cladding back through the coatings it had already traversed where absorption occurred for a second time, and finally entered the core once more. In summary, light escaped the core, travelled through one or more layers of coatings, there to be selectively absorbed, and was reflected back into the core. Thus, light reentering the core corresponded, at least roughly, to the "absorption spectrum" of the traversed coatings and led to selective signal attenuation. Once the nature of these problems was determined both were susceptible to a common solution. If any coating contained one or more components which efficiently absorbed the light entering the coating the problem could be expected to be effectively solved for the case of incident light. If the coating containing the light-absorbing component was placed between the primary cladding and the secondary cladding both problems would be solved. In fact, that turned out to be correct in the foregoing cases. SUMMARY OF THE INVENTION The purpose of this invention is to reduce or eliminate extraneous light entering the core of an optical fiber. An embodiment comprises the addition to a coating of at least one component absorbing light within the range of wavelengths traveling along the core of the optical fiber. In a more specific embodiment the component is charcoal in any of its forms. In a more specific embodiment charcoal is present in an amount from about 0.1 up to about 10 weight percent of the coating. In yet another embodiment the light absorbing component is added in an amount effective to absorb at least 90% of the extraneous light at least at those wavelengths of radiation injected into the core. In still another embodiment the optical fiber is coated with an elastic polymer containing at least one light absorbing component in an amount effective to absorb at least 90% of the offending extraneous light. Other embodiments will be apparent from the ensuing description. DESCRIPTION OF THE INVENTION This invention relates to optical fibers transmitting light, especially radiation in the ultraviolet-visible-near infrared-infrared portion of the light spectrum. For the purpose of this application, the light spectrum of greatest interest is between about 200 and about 30,000 nm, and more particularly from about 200 up to about 2500 nm. In the more usual case, the optical fiber of our invention will be transmitting light of only a limited wavelength range within the foregoing spectrum, and in fact the more relevant parameter is the range of wavelengths whose intensity is measured at the exit of the optical fiber, irrespective of the range of wavelengths travelling within the fiber. The wavelength range Δ will in this application represent the wavelength range measured at the exit of the optical fiber and usually, although not necessarily, also will correspond to the wavelength range of the light being transmitted along the optical fiber. It should be clear that only light of wavelengths within Δ are of importance in our invention. We previously have defined "extraneous" light as that entering the core of an optical fiber through the primary cladding. By "offending" light is meant extraneous light within the wavelength range Δ as that term is defined above. It also should be explicitly recognized that material constraints place limitations on spectral range which only reflect practical limitations. Thus, most quartz fibers transmit light only up to about 2500 nm. Optical fibers of zirconium fluoride can carry light of wavelength up to ca. 4000 nm. Chalcogenide fibers may extend that range to about 14,000 nanometers. Thus, the limitations in materials available as optical fibers place constraints on the spectral range of light carried by the fiber. The optical fibers of our invention have at least one and usually several coatings arranged concentrically around the cladded core. In at least some cases one or more of the coatings also act as a secondary cladding, reflecting light which escapes from the core through the primary cladding back into the core. The coatings generally are organic polymers, some of which may be elastic polymers. As previously stated, we have observed that under some conditions there is extraneous light, which includes both 1) the case where the extraneous light is ambient light entering from outside the fiber and 2) the case where extraneous light is light which escapes from the core via scattering and via loss of total internal reflection at bends in the fiber and is reflected from a coating acting as a secondary cladding. What is necessary is to prevent the extraneous light which has entered any coating external to the primary cladding from entering, or reentering, the core of the optical fiber. The extraneous light which has entered a coating is prevented from getting into the core of the optical fiber by having present in the coating a light absorbing component. It is only necessary that this component absorb light within the wavelength range Δ since only that range of wavelengths is being measured, or transmitted and measured. The light absorbing component is present in an amount such that it absorbs at least 90% of the offending radiation, although it is preferable that it absorbs at least 95%, and yet more preferable that it absorbs at least 99%, or substantially all, of the offending radiation. One light absorbing component which is particularly desirable is particulate amorphous carbon, in all of its various forms, because it is effective to absorb radiation over a very broad range of the spectrum of interest. By "particulate amorphous carbon" is meant charcoal in all of its various forms and however it may be referred to, such as decolorizing carbon, lamp black, carbon black, activated carbon, activated charcoal, and so forth. It needs to be understood that the success of our invention does not depend on the nature or source of the particulate amorphous carbon used, but rather on the fact that we use particulate amorphous carbon dispersed throughout the polymeric coating. When particulate amorphous carbon is used it may be employed in a concentration as little as about 0.1 weight percent up to as high as about 10 weight percent of the coating. However, it should be recognized that some polymer properties may be adversely affected (for example, strength loss) with increasing concentrations of carbon black. Consequently, it is more preferable that particulate amorphous carbon concentrations do not exceed 5 weight percent, and even more preferable that concentrations do not exceed about 2 weight percent. It also should be clear that many other light absorbing components may be used. In particular, other dyes may be used which are effective light absorbers over more or less narrow ranges of the light spectrum. This variant may be particularly useful when problems arise in only a very narrow and limited range of the light spectrum, for in those cases the light absorbing component may be carefully chosen to correspond to the problem areas within the spectrum. The identity of the coating is not of particular importance and it is known that a rather broad range of materials are presently used. Examples of suitable elastic polymers as coatings include silicones, acrylates, urethanes, and rubbers, whether thermally cured or ultraviolet cured. Examples of hard polymeric coatings include polyimides, polyacrylates, and so forth. As stated above the most generally effective placement of the coating containing the light absorbing component(s) is between the primary and the secondary claddings, for with such placement extraneous radiation from both an external source as well as from failure of total internal reflection can be absorbed. Where only radiation from an external source is a problem the coating containing the light absorbing component(s) may be located anywhere external to the primary cladding. The foregoing description was couched in terms of discrete fibers. However, in many uses fibers are bundled to afford an ensemble with each fiber core carrying its own discrete spectrum of radiation. In such cases having on each fiber a coating which contains the light absorbing components of our invention also can be expected to be useful, especially in preventing "crosstalk" between adjacent fibers. It should be clear that our invention encompasses this variation as well. The following examples illustrate our invention but are not intended to limit it in any way. EXAMPLE 1 Extraneous light via secondary cladding. An optical fiber was drawn from a commercially available preform, coated with a thermally cured polyimide (from DuPont) and sheathed in a thermally cured silicone. The fiber was used to transmit light in the 1000-2300 nm range, and intensity measurements were made on various coils of fiber of different bend radius vs. unbent fiber as a reference. Significant attenuation was noticed at wavelengths corresponding to absorption peaks of the polyimide. Absorption varied with the bend radius, further supporting the view that light leaks from the core of the bent fiber, i.e., it escapes from the core because of failure of total internal reflection. The leaked light internally reflects off the silicone sheath acting as a secondary cladding after being absorbed by the polyimide, and is absorbed again by the polyimide before reentering the core of the fiber. EXAMPLE 2 Extraneous light via ambient light. The basic optical fiber was the same as described above with a polyimide coating and was 500 microns in diameter. Spectra of chloroform were obtained at various wavelengths in the 1000-2100 nm range using as the fiber on the source side of the analyzer, i.e., fiber transmitting light to the sample, one having a thermally cured silicone sheath, an ethylene-tetrafluoroethylene copolymer (Tefzel from DuPont) jacket, a Kevlar™ braid, and an outer Tefzel jacket, with the jacketed fiber wrapped in aluminum foil. The detector side of the analyzer was connected to 6 meters of different fibers, one being a bare fiber (only polyimide coated) and the other also having a silicone sheath containing 1 weight percent carbon black. The latter were coiled, covered with aluminum foil from their connection points to the coil, and placed in an aluminum foil lined box. Scans of chloroform in a 50 mm cuvette were obtained, both with the coils illuminated by a 100 W bulb held 7 inches from the coil and without illumination. Table 1 gives the difference (in absorbance units, AU) in light transmission at 4 points. Since chloroform is virtually opaque at these wavelengths under the foregoing path length, these are quite sensitive measurements for stray light. TABLE 1______________________________________Effect of Ambient Light AU DifferenceFiber 1151 nm 1408 nm 1679 nm 1860 nm______________________________________Bare 0.0441 0.0947 0.1891 0.2478Silicone + 1% C 0.0004 0.0011 0.0014 0.0008______________________________________ The foregoing data show both that light from an external source enters the core through the coatings, and that the addition of carbon to a silicone coating effectively absorbs the extraneous radiation over the measured wave length region.

Optical fibers having one or more polymeric coatings have been found to be sensitive to extraneous light arising either as incident light from outside the optical fiber or as light escaping the fiber at bends and being reflected back into the fiber by a coating acting as a secondary cladding. In either case the extraneous light intensity may be reduced by placing at least one light absorbing component in a coating. Where the light absorbing component is placed in a coating between the primary cladding of the optical fiber and the secondary cladding both sources of extraneous light may be reduced or eliminated. Particulate amorphous carbon is an effective light absorber because of the broad range of optical wavelengths absorbed and because of its efficiency of absorption (high extinction coefficient) over this range.

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority based on U.S. Provisional Patent Application Ser. No. 62/016,544 filed Jun. 24, 2014 and titled “PUMP AND DELIVERY TUBE,” the disclosure of which is incorporated herein in its entirety by this reference. BACKGROUND This application relates generally to personal hydration systems, such as backpacks that carry water for use during exercise, and in particular to an electrically powered pump and a delivery tube that may be affixed to a hydration bladder of a personal hydration system. Such hydration systems are often used by participants in cycling, hiking, racing, skiing and other outdoor activities. When exercising, participants often want to carry water or another hydrating liquid. This is particularly true when the participant is going a significant distance between possible water stops. Often, people do not want to carry a rigid or semi-rigid water bottle in their hands or backpacks. Therefore, there are a number of hydration devices on the market today that improve upon the rigid water bottle commonly seen on bicycles and found in the backpacks of hikers. These hydration devices typically carry a larger volume of liquid, often use flexible bladders to hold the liquid, and typically have a tube coming out of the bladder from which the liquid can be dispensed. Hence, these hydration devices can be effective in keeping the end user hydrated during physical exercise or during hot weather. Examples of such devices are disclosed in U.S. Pat. Nos. 4,095,726; 4,420,097; 4,948,023; 5,060,833; 5,085,349; 5,282,557; 5,427,290; 5,645,404; 5,727,714; 5,722,573; 5,806,726; 5,864,880; 5,911,406; 5,941,640; 5,975,387; 5,984,145; 6,032,831; 6,039,305; 7,007,826; and 8,220,664; the entire disclosures of which are incorporated herein by this reference. These hydration devices have other ancillary uses. For example, a larger hydration device that delivers liquid under pressure on demand would also be convenient in sharing of the liquid with a thirsty friend, washing out a wound, or washing dirt or mud off of a surface. These ancillary uses can be tricky when the liquid must be suctioned out, forced out by pushing on the bladder, or require gravity to cause the liquid to flow. Attaching a pump, such as a pump powered by squeezing or other exertion by the user, further complicates use of the hydration system because the pump interferes with many physical activities. In addition, prior devices may be difficult for athletes involved in physical exertion and high respiration rates to use. During such activity, it may take significant effort to stop breathing and to suck liquid from the hydration system. Another prior attempt to provide liquid under pressure on demand involved including a tank or bladder, of air under pressure, attached to the regular hydration bladder of liquid (which in effect squeezes the hydration liquid bladder) to force the liquid through the output tube. Adding the additional volume of an air pressure bladder is wasteful of the limited space and inconvenient. In addition, the pressure curve (of the stored air pressure bladder) goes downward as liquid is used and thus must be periodically pumped up during the emptying of just one bladder. This causes the pressure of the liquid stream to be inconsistent. That is, the output stream of water from the bladder starts out strong but the pressure goes down with each use and is typically insufficient to empty a whole bladder of water, thus requiring the end user to carry a pump and to devote time and effort to re-pressurizing the system. Thus, considerably less energy may be expended if the liquid from the hydration system could be automatically pumped through the drinking tube without the user expending significant effort or time. Such a system may give a competing athlete a measurable advantage over competitors. Furthermore, such a system would permit easy sharing of liquids with a friend, and may permit washing of a wound or dirty surface with what amounts to a low pressure stream of water. SUMMARY According to the present disclosure, a small, light-weight, in-line pump assembly connects to the existing liquid output port of the bladder of a hydration unit. The in-line pump assembly attaches to a drinking tube through which a user may suck water (or other liquid) from the bladder. A casing in the in-line pump assembly contains an electrically driven fluid delivery pump that is configured to pump liquid from the bladder and through the in-line pump assembly and the drinking tube to the user. According to one embodiment, an expanding and contracting bulb system inside the delivery tube activates the fluid delivery pump by simply pressing a bite valve. That is, a switch line runs inside the drinking tube from the pump casing to a bite valve at the output end of the drinking tube or delivery tube. An expandable switch bulb affixed to the end of the switch line extends into the casing. The switch bulb abuts a pressure switch, so that when liquid is forced into the switch bulb, the switch bulb expands and the switch is closed, thereby activating the pump. The bite valve at the delivery end of the switch line contains a bite valve bulb. When a user has the delivery end of the drinking tube in their mouth, the user may bite down on the bite valve, which will cause the liquid in the bite valve bulb to flow out of that bulb and into the switch bulb at the other end of the switch line. The liquid in the switch line is essentially incompressible, and thus when the user bites the bite valve, that liquid pressure causes the switch bulb (on the other end of the switch line) to expand, thereby closing the pressure switch. This design has the advantage of not having electricity in the bite valve and therefore in the user's mouth (or anywhere around the user's mouth). The present in-line pump assembly may be designed, with appropriate different adapters, to attach to multiple brands of hydration systems and therefore is an accessory to the personal hydration system. The pump and delivery hose can be quickly attached or removed. Furthermore, in the event that the battery is discharged or depleted, the user may continue to suck fluid from the hydration system even after the energy source for the pump is depleted. While any of these advantages are possible, it may be the case that only some or even none of them are made use of in connection with the present invention. Whatever the case, the present invention includes systems comprising any of these features described herein. Methodology described in association with the devices disclosed also forms part of the invention. The invention further comprises such hardware and methodology as may be used in connection with that described, all of which is incorporated by reference. BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the present invention will be apparent from the following Detailed Description taken in conjunction with the accompanying Drawings, in which: FIG. 1 depicts a plan view of a hydration bladder with the present pump and tube apparatus attached thereto; FIG. 2 depicts an exploded view of the pump and tube apparatus depicted in FIG. 1 ; FIG. 3 depicts an exploded view of an in-line pump assembly of the apparatus depicted in FIG. 1 ; FIG. 4 depicts an exploded view of a pump of the present apparatus according to one embodiment; FIG. 5 depicts a cross-sectional view of the pump housing, pump and tube of the apparatus depicted in FIG. 1 according to one embodiment; and FIG. 6 depicts a switching mechanism for the pump and tube apparatus depicted in FIG. 1 according to another embodiment. DETAILED DESCRIPTION As depicted in FIG. 1 , a typical personal hydration system 10 comprises a bladder 12 having a input port 14 that may be sealed by a screw-on cap 18 . To fill the bladder, the cap is screwed off, liquid is poured into the bladder, and the cap is screwed back on to the bladder. The bladder also has a drain port 20 from which the liquid is dispensed out of the bladder. In the embodiment shown in the FIGURES, the drain port includes a bladder connection barb 22 to which a drinking tube of appropriate diameter may be attached. In other embodiments, a quick release mechanism is formed or attached as part of the drain port. According to the present disclosure, an in-line pump assembly 24 may be connected to the bladder connection barb 22 (or other mechanism) of a new or existing hydration bladder 12 . The in-line pump assembly 24 includes a pump and a tube to assist in delivery of liquid from the bladder to a user. In the embodiment depicted in FIGS. 1 and 2 , a short adaptation tube 28 is removably mounted between the bladder connection barb 22 and a pump input connection barb 30 formed on a tapered end cap 32 at the input end of an outer pump housing 34 (see FIG. 3 ). Although the adaptation tube 28 is depicted in FIGS. 1 and 2 , depending on the style or manufacturer of the bladder 12 , the connection between the bladder and the pump housing may take the form of a quick release mechanism or other design that is compatible with the bladder. A drinking tube 38 is removably mounted to a pump output connection barb 40 that is formed on an output end cap 42 formed in, or affixed to, the second end (or output end) of the pump housing 34 . Again, different connection mechanisms may be used. Inside (or mounted alongside, in other embodiments) the drinking tube 38 resides a removable, flexible, hollow switch line 44 with expandable bulbs formed or attached on each end. One bulb, a bite valve bulb 48 , fits into a bite valve 50 on the delivery end of the drinking tube 38 . The other expandable bulb, a switch bulb 54 (see FIG. 5 ), is mounted in a switch bulb holder 56 held inside the inner pump cap 58 that is attached to the pump housing 34 (see FIG. 4 ). As depicted in FIG. 3 , the in-line pump assembly 24 comprises the outer pump housing 34 having, at the input end of the outer pump housing, the tapered end cap 32 with formed pump input connection barb 30 . The output end cap 42 with formed pump output connection barb 40 attaches to the opposite end of the outer pump housing 34 , typically with an O-ring 64 to seal liquid inside the housing. A pump 62 is held within the housing 34 . As depicted in FIGS. 4 and 5 , the pump 62 includes a motor 68 that is powered by a battery 70 (or other energy store). The battery may be kept in place by a battery holder 72 on which a pressure switch 74 is also attached. In the embodiment depicted in FIG. 4 , the motor and battery are held within a pump casing 60 that is sealed off from the hydration liquid at one end by an O-ring 52 and the inner pump cap 58 and at the opposite end by a press-fit lower pump cap and stabilizer 82 . In this embodiment, the switch bulb holder 56 screws into the inner pump cap 58 , and is typically sealed with the assistance of an O-ring 92 . A multi-bladed impeller 84 is mounted on the drive shaft 88 of the motor 68 . The impeller is shrouded by the tapered end cap 32 . In the embodiment depicted in FIG. 5 , for efficiency, the taper of this end cap typically matches or closely matches the contour of the impeller, but other embodiments could be implemented, to vary the flow characteristic of the hydration liquid, that did not follow the contour of the end cap. According to this embodiment, the lower pump cap and stabilizer 82 is press-fit into the pump casing 60 . O-rings 93 and 94 are placed on the motor shaft 88 on both sides of the lower pump cap and stabilizer 82 to help seal the entry end of the pump 62 . The other (exit) end of the pump 62 is sealed from the hydration liquid being pumped by the inner pump cap 58 , typically with the O-ring 52 between the inner pump cap and the casing 60 . As depicted in FIGS. 3 and 5 , two arms 96 formed on the inner pump cap 58 fit flush into notches 97 formed on the inside of the outer pump housing 34 to prevent the pump 62 from twisting within the outer pump housing 34 . This flush fitting allows the O-ring 64 to seal between output end cap 42 and outer pump housing 34 . Posts 98 formed in the lower cap and stabilizer 82 abut against the interior diameter of the outer pump housing 34 to center and to stabilize the lower end of the pump 62 so that the impeller 84 blades do not rub or come in contact with either the outer pump housing 34 or the tapered end cap 32 . Alternatively, stabilizing vanes or other mechanisms could be used. The purpose is to keep the impeller stable during pumping of the fluid, thereby making the device more efficient. The switch line 44 and the switch bulb 54 and bite valve bulb 48 hold an essentially incompressible liquid and thereby form a sealed unit. Compressing the bite valve bulb 48 causes the non-compressible liquid to travel through the switch line 44 , thereby causing the switch bulb 54 to expand. The switch bulb is mounted against a pressure switch 74 on the battery holder 72 . Thus, when the switch bulb 54 expands, the abutting pressure switch 74 is closed, thereby actuating the motor 68 . The motor turns the impeller 84 , causing the hydration liquid (or other liquid in the bladder 12 , such as an antiseptic liquid or a vitamin supplement or a cleaning liquid) to be pumped from the bladder drain port 20 through the pump housing 34 , through the drinking tube 38 , and to exit under pressure through the bite valve 50 . In other embodiments, rather than using the bite valve bulb 48 , switch bulb 54 , and hollow switch line 44 , the pump assembly 24 can be activated by a bluetooth (or other frequency or communications protocol) remote switch typically attached to a bicycle handle bar or carried inside the user's pocket. As depicted in FIG. 6 , in this embodiment an actuator 100 resides inside the pump 62 between the battery 70 (or other energy storage) and the inner pump cap 58 and attached to battery holder 72 . A switch holder 102 is mounted to a handle bar 106 or paddle by a plastic zip tie or other attachment method (such as a half circle mount with two screws). A remote switch 104 snaps into and out of the switch holder 102 so that the remote switch may be removed and carried within frequency range of the in-line pump assembly 24 . This enables the personal hydration system 10 , with in-line pump assembly 24 , to be used in other applications. Pressing the remote switch 104 sends a signal to the actuator 100 , which then activates the pump 62 to send pressurized liquid to the bite valve 50 for use. Releasing the remote switch deactivates the pump 62 and stops the flow of liquid from the bite valve 50 . Thus, the present in-line pump assembly 24 overcomes the problem of requiring the user to exert effort or stop breathing to suck liquid from the hydration system. The user may easily share water with others, significantly reducing the risk of disease transmission that sharing of the bite valve might create. The same is true of using the hydrating liquid to clean a wound. The present assembly is also light-weight, takes up very little additional space, and will expel liquid at a generally stable pressure over the life of the battery or other stored energy source. Also, the present design may have sufficient power to pump out several bladders full of liquid without requiring a replacement battery or re-charging of a stored energy source. According to other embodiments, the in-line pump assembly 24 may be mounted on liquid reservoirs to be used to water plants, transfer liquid from one location to another, administer vitamins or antibiotics to children in war torn or impoverished areas. Furthermore, because the liquid flow is not blocked by the pump 62 , should the battery power run out, the user may still suck out the liquid, or may use gravity or pressure on the bladder 12 to force the liquid through the drinking tube 38 . The present delivery mechanism provides a user with hydrating liquid essentially on demand, and without requiring suction or other potentially difficult effort or distraction while exercising or during competition. Thus, the present device has several advantages over the prior art. It will be obvious to those of skill in the art that the invention described in this specification and depicted in the FIGURES may be modified to produce different embodiments. Although embodiments of the invention have been illustrated and described, various modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the invention.

An in-line pump assembly attachable to a hydration bladder includes an electrically driven pump held in a casing and placed in the flow of hydrating liquid. The pump connects to the outlet of the hydration system. Bulbs at the respective ends of a switch line hold an essentially incompressible liquid. Pinching a bite valve bulb on the output end of the drinking tube cause a switch line bulb on the other end of the switch line to expand, closing a pressure switch and causing the pump to pump liquid from the hydration bladder through the drinking tube. Releasing the bite valve bulb reduces the pressure in the switch bulb, disengaging the switch and stopping the flow of liquid. The in-line pump assembly may be connected to a preexisting hydration system through an adapter.

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation of Ser. No. 07/540,910, filed Jun. 20, 1990 (now abandoned), which was a continuation-in-part of Ser. No. 07/352,689, filed May. 10, 1989, (now abandoned) which was, in turn, a continuation of Ser. No. 07/139,075 filed Dec. 28, 1987, now abandoned, which was, in turn, a continuation of Ser. No. 06/871,066 filed Jun. 5, 1986, now abandoned. BACKGROUND This invention relates to means for and methods of mixing and activating or inverting polymers, at a high speed, and in either batch or continuous loads, while being able to control, select and maintain polymer concentration and activation. The term "activation" is widely used to describe the chemical transition of polymer to a usable form. Recently, the terminology has tended to focus on how much activation has occurred with some arguing that there must be 100% activation before the word can be used. Since nothing is ever perfect, it is seen that if this argument is carried to the extreme, very little polymer would ever be 100% activated. As used herein, no such fine level of distinction is made. The word "activated", in its many forms, is intended to encompass the start of the process and everything occurring thereafter. Perhaps the word "inversion" might be more appropriate since it applies regardless of the degree of completion of the activating process. Liquid or emulsion polymers are ionic-charged organic molecules which are soluble in water or another electrolytic fluid, which are herinafter simply called "water". Unactivated or neat polymers are encased by an oil carrier. In this phase, the molecule is coiled upon itself in a microgel form suspended in the oil carrier. Due to its charge, it tries to uncoil, but the oil carrier overcomes the charge and keeps it coiled. Liquid polymers are used by various industries to simplify their industrial processes and make them more economical. For example, liquid polymers may be used for water purification and flocculation; may be used in automotive paint spray booths; may be used in the chemical industry to separate inorganics and solids from plant effluent; may be used in the coal industry to promote solids settling and to float coal fines; may be used in the petro-chemical industry to enhance oil recovery; may be used in the phosphate industry to improve recovery; may be used in the pulp and paper industry as dewatering aids and retention aids; or may be used in the steel industry to settle wastes. Those familiar with this art will readily perceive many other uses in many other industries. Usually polymers are manufactured and shipped in a deactivated form to a location where they will be used. At that location, it is necessary to activate or invert the polymers before they can be used. Usually, that means that a polymer must be mixed with water or other electrolyte (solvent), or with a chemical, to provide an electrolyte which can change the polymer from an inactive state into an active state which can be so mixed. The process for so converting the polymer into an active state is one of imparting a sufficient amount of energy to the polymer. Reference may be made to U.S. Pat. Nos. 4,057,223, 4,218,147 and 4,217,145 for examples of prior art polymer activating systems. The polymer encased in the oil phase is inactive. Therefore, its hydrocarbon surroundings must be emulsified or broken to allow the ionic molecule to uncoil or hydrate. This process of hydration is called activation or inversion. The way in which emulsion polymers are activated are to dilute them with water and to add enough mixing energy to emulsify the oil carrier and thus to enable the ionic charged molecule to uncoil. More particularly, the energy imparted to the inactive polymer includes a mechanical agitation which breaks down the hydrocarbon carrier phase, and thus enables water to reach and react with the long coiled molecule. Once that molecule is in water, like charges on the molecule repel each ocher and the molecule straightens and changes from the coil into a long and more or less straight "conformation". Until this conformational rearrangement occurs, the molecule is useless for most purposes. The exact amount of energy required for an emulsion polymer activation is not known. However, there is an increase in the viscosity of the polymer, which is proportional to its stage of activation. This increase in viscosity is due to the uncoiled molecules intertwining with each other. The uncoiling of the molecules provide active sites for the attachment of foreign material in a medium. Then, the increased weight on these molecules settles them, carrying with them the settled material. In the utilization of emulsion polymers, care must be taken to properly prepare the polymer. Different polymers require different amounts of energy for activation, tougher polymers require more force, while others need less force. Further, care must be taken not to overshear the molecules. Overshearing tends to break the uncoiled molecules, thus lowering their viscosity and making them less effective. Undershearing also is deleterious in that the polymer is then inefficient and uneconomical. The known activating systems have required relatively long periods of time (such as an hour or so) in order to, for example, complete the inversion of the polymer. This long period of time increases the requirements for holding tanks during activation. Therefore, the relatively long period of activation time is relatively expensive. Also, the requirement for such a long term for activation greatly increases the capital requirements for the purchase of machinery when a system is operating continuously, as opposed to a batch system. Thus a faster polymer activating system is highly desired. Primarily, the prior art used the batch method to invert liquid polymers. Polymer and water are delivered to a common mixing tank. Once in the tank, the solution is beat or mixed for a specific length of time in order to impart energy thereto. After mixing, the resulting solution must age to allow enough time for the molecules to unwind. There are many different kinds of polymers which leads to a plethora of application requirements. It might be easy to build an entirely new custom designed system or machine for each and every different polymer activation job; however, the cost would then become prohibitive. This highlights the need for a great flexibility for a polymer activation system or machine, which in turn leads to the need for alternative mechanisms which may be added to or removed from the activating hydraulic circuits according to the then current needs. One way to satisfy both the greater flexibility and a reduced system cost is to adjust the system to process a greater concentration of polymer. For example, instead of producing an output fluid which is 1% polymer, the system may be adjusted to produce a more concentrated fluid which is 2% polymer. Then, the concentrated 2% outflow may be diluted downstream to become 1% polymer, which would double the volume produced by a relatively small machine, to become the volume of a machine of twice the size, if it was originally designed to process a polymer as a 1% fluid. The activation process continues long after the discharge of the inverted polymer from the system outlet. Merely adding more water in the primary dilution of a polymer might very likely wash away necessary inverting agents, called "activators" or surfactants which are useful in emulsifying the hydrocarbon carrier. For example, a particular use of a particular polymer might require a tenth percent (0.1) polymer solution, but the polymer would lose necessary chemical components if an effort is made to dilute the polymer this much in a single pass through the system. Once a polymer is inverted, there is little, if any, need for retaining these chemical activators. Therefore, the invention presents the opportunity to invert a polymer solution to, say, one percent. (1.0) Once the polymer is inverted, the solution may be diluted downstream to reduce the one percent solution to become a tenth percent solution. Hence, in this example, with the invention, it is possible to produce a tenth percent solution that could not have been produced heretofore. Two examples of dilution systems which have been designed with these thoughts in mind are found in Rosenberger's and Brazelton's U.S. Pat. Nos. 4,128,147 and 4,642,222. Each of these patents shows a method of adding dilution water to an inverted polymer as it exits a system, thereby theoretically enabling the system to deliver higher concentrations of polymer which are then diluted to give a greater volume of total output. However, it is thought that each of these patents contain basic design flaws since each subjects activated polymers to abrupt pressure changes or additional mixing once the polymer has reached its extended state. That is the output lines of these patents include pressure regulators and/or mixing devices which will create a higher upstream pressure as compared to a lower downstream pressure. Once a polymer is activated, such a pressure change or additional mixing may cause shear and break the now linear polymer molecule, thereby damaging or destroying the polymer. According to FIG. 1 of the Rosenberger patent the polymer solution is subject to a pressure drop as it passes through the second fixed flow rate regulator. Brazelton teaches the reduction or increase in the input of polymer flow to his mixing system instead of varying the water flow. SUMMARY Accordingly, an object of the invention is to provide new and improved means for and methods of activating polymers. Another object of the invention is to provide flexible polymer activating systems or machines, which may be adapted to fit the needs of particular polymers which are being processed. In particular, an object is to provide means for activating concentrated polymer solutions and for thereafter introducing downstream a secondary dilution to bring the concentrate into a useful range before the molecules become fully hydrated. Yet another object of the invention is to provide an efficient system and method for activating liquid polymers. Here an object is to provide an automatic, continuous system which is able to vary the output rate of inverted polymer, while automatically maintaining the amount of energy imparted thereto and while maintaining a desired concentration of the polymer. In particular, an object is to monitor the level of active solids in an outflow from the system and to provide system control functions in response to the level detected during the monitoring in order to maintain greater stability. In keeping with an aspect of the invention, the activation of a polymer occurs in four stages, which are: pre-mixing, blending, recycling, and a final sudden pressure reduction. The pre-mixing occurs in a manifold containing a static mixer. The blending occurs within a centrifugal pump where water is blended with the polymer. The outflowing stream from the centrifugal pump divides with part of the outflow feeding back through the static mixer and centrifugal pump. The other divided part of the outflow is delivered to a mixing pressure regulator where the pressure imparted by the centrifugal pump is suddenly reduced to, or near, atmospheric pressure. This suddenly relaxes the coiled, long polymer molecule to hasten its straightening. This system provides three different kinds of shear which are imparted during the inversion of the polymer fluid. First, there is a boundary layer shear occurring in the centrifugal pump. Second, there is a visco-elastic shear at an orifice where the polymer fluid flows faster at the center of the orifice than at the periphery of the orifice. Third, there is a structuring shear when the pressure suddenly reduces as the polymer solution passes through the mixing pressure regulator. In one exemplary inventive system, the entire inversion requires only about one second. The invention enables an adjustment which controls the amount of energy introduced into the polymer for inversion. Once the relationship between the amount of introduced energy and the output rate is established, the inventive system automatically compensates for variations therein. The system also provides controls for varying the concentration of the polymer. A secondary fluid delivery system may dilute the concentrated polymer after it is inverted. BRIEF DESCRIPTION OF DRAWINGS Preferred embodiments of the invention are shown in the attached drawings, wherein: FIG. 1 schematically shows the principles of an inventive system having two inputs, which are for water and for the polymer that is to activated; FIG. 2 is a perspective view of a pre-mixing manifold; FIGS. 3A and B are two plan views (rotated by 90° from each other) a static mixer which is used inside the manifold of FIG. 2; FIG. 4 is an end view of the static mixer, taken along line 4--4 in FIG. 3A; and FIG. 5 is a schematic showing of a more sophisticated version of the system of FIG. 1 with provisions for introducing one or more chemicals which may be used in the electrolyte for activating the polymer; FIG. 6 is a front plan view of a system incorporating the invention; FIG. 7 is a plan view of the inventive system taken along lines 7--7 of FIG. 6; FIG. 8 is a schematic disclosure of a prior at system for introducing secondary delivery; FIG. 9 is a schematic diagram of an inventive system for introducing a diluent via primary and secondary legs; FIG. 9A is a cross-section of a pilot valve used in FIG. 9; FIG. 9B is part of FIG. 9 with an automatic control for maintaining a ratio of flows in primary and secondary legs of an electrolyte delivery system; FIG. 10 is a front elevation of the inventive machine having secondary dilution capabilities; FIG. 10A shows an alternative wet polymer sensor for use in FIG. 10; and FIG. 11 is a top plan view of the machine of FIG. 10. DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1, the polymer inverting and activating system 18 components are an input throttling valve 20 for controlling the ratio of water to polymer, a centrifugal pump 22 for introducing the water, a closed mixing loop 24, a pre-mixing manifold 26, and a centrifugal pump 28 for introducing the polymer. The water and polymer first meet in the pre-mixing manifold 26, the water flow being indicated in FIG. 1 by solid lines and the polymer flow being indicated by dashed lines. Valve 20 may be set to provide a ratio of water to about 1% polymer, in one example, with a useful ranger of ratios being in the order of 0.25 to 15% polymer. Associated with valve 20 may be a meter (not shown) which is calibrated in gallons per minute. By an adjustment of the valve 20, one can also select the desired output of the system, or a more highly concentration of inverted polymer solution. The mixing pressure regulator 30 is critical in three areas. It is used to maintain a constant net positive discharge head on the booster module or centrifugal pump 22, which is an important consideration in the hydraulics of the system. It controls the amount of recycling which occurs in the recycle stage. It provides a variable pressure drop zone in the final stage and enables the operator to select a proper amount of mixing energy, based on the type and concentration of polymer being processed. The higher solids polymers and higher solution concentrations require more mixing energy than usual. In greater detail, the mixing manifold 26 (FIG. 2) is, for example, a solid block of metal having a central bore 32 extending through substantially its entire length. The bore 32 stops short of a counterbored and threaded input opening 34, to form a bulkhead 36. An orifice 38 of fixed diameter is formed in the center of the bulkhead 36 to establish communication between the water inlet hole 34 and the central bore 32, with a flow rate that is controlled by the orifice diameter. The polymer solution experiences an extrusion type of shear as it passes through the orifice 38. TABLE I______________________________________AN EXEMPLARY FLOW RATE AND RECYCLEVOLUME IN ONE EXEMPLARY SYSTEM DIAMETER SOLUTION RECYCLETYPE OF OF OUTPUT VOLUMEPUMP ORIFICE 38 (GPM) GPM______________________________________054 AnCAT 3/32" to 3/16" .25 to 10 gpm 1.85 @ 40 psi to 8.12 @ 60 psiL-10 AnCAT 1/8" to 1/4" 3 to 10 gpm 2.56 @ 30 psi to 14.5 @ 60 psiL-20 AnCAT 1/8" to 1/4" 3 to 20 gpm 2.56 @ 30 psi to 14.5 @ 60 psiL-30 AnCAT 1/8"to 3/8" 3 to 30 gpm 2.56 @ 30 psi to 32.5 @ 60 psiL-60 AnCAT 3/16" to 1/3" 5 to 60 gpm 5.75 @ 30 psi to 57.8 @ 60 psiL-80 AnCAT 3/16" to 5/8" 5 to 80 gpm 5.75 @ 30 psi to 90.4 @ 60 psiL-100 AnCAT 3/16" to 3/4" 5 to 100 gpm 5.75 @ 30 psi to 130.0 @ 60 psi______________________________________ The last or recycle column indicates that the recycled or returned output from the derated pump 15 is in the order of about 5% to 70by volume. These figures are derived from a Cameron Table, which a conventional tool for hydraulic engineering. The converse statement would be that the outflow is 95% -30% by volume. A first threaded hole 40 leads to another bulk head 42 between the entrance to the counter bored and threaded hole 40 and the central bore 32. An orifice 44 is formed in the bulkhead 42 to establish communication and to control the flow rate between the hole 40 and the central bore 32. The output port 46 is in direct communication with the central bore 32 to give an unimpeded outflow of a mixture of polymer and water. A static mixer 50 (FIGS. 3,4) comprises two sets of semi-elliptical baffles which are set at an angle with respect to each other so that the over all end view configuration is a circle (FIG. 4). The baffles 52 (FIG. 3A) on one side of the static mixer are a series of spaced parallel plates. The baffles 54 on the other side of the static mixer are Joined on alternate ends to give an over all zig-zag appearance. The outside diameter of the static mixer corresponds to the inside diameter of the central bore 32. Therefore, the static mixer 50 slides through an end opening 56 and into the bore 32. Thereafter a plug 58 seals off the end of the bore. In one embodiment, the static mixer 50 is a standard commercial product from TAH Industries of Inlaystown, N.J. Water is introduced through the centrifugal pump 22 and into the mixing loop 24 (FIG. 1). The flow of water is controlled and metered by the throttling flow valve and meter at 20. The beginning stages of activation or the pre-blend stage occurs inside the centrifugal pump assembly 22. The centrifugal pump 22 is a modified commercial item which is derated on the high end of its output flow by a factor in the order of 2 to 7, for example, for most applications. On the low end of its output flow, the derating factor may be much higher. That is the diameter (for example) of the impeller is trimmed to give a derated performance wherein there is a larger amount of stirring and mixing per volume flow, as compared to what might normally be expected from standard commercial centrifugal pump. Other techniques for derating an impeller including changing a pitch of the blades, thinning the width of blades, and the like. Derating is also controlled by an adjustment of the water inlet flow. In greater detail, by way of example, a centrifugal pump usually has a series of flow charts which are supplied by the manufacturer. One flow chart, which may be the one normally used, may describe how the pump could provide a flow of 20 gallons per minute to the top of a 40 foot head, for example. Another flow chart may describe how the same pump could be operated at a different speed to provide five times that capacity, or at 100 gallons per minute to the same 40 foot head, in this particular example. According to the invention, the pump is operated, for example, in the manner described by the manufacturer to deliver 100 gallons per minute, but the diameter of the impeller is reduced until the delivery returns to 20 gallons per minute, while the pump continues to be operated in the manner which the manufacturer suggests for 100 gallons per minute. Thus, in this particular example, the centrifugal pump has been derated by a factor of 5 (i.e. derated from 100 to 20 gallons per minute). After derating, the increased impeller speed, which is normally required to deliver 100 gallons per minute imparts a higher level of energy to the mixed fluid, without increasing the volume of fluid output. The following chart illustrates a number of different centrifugal pumps which may be used for polymer injection at pump 28. ______________________________________TYPE PUMP FLOW RATE______________________________________054 AnCAT 0-864 gpdL-10 AnCAT 0-2160 gpdL-20 AnCAT 0-4320 gpdL-30 AnCAT 0-6480 gpdL-60 AnCAT 0-12,960 gpdL-80 AnCAT 0-17,280 gpdL-100 AnCAT 0-21,600 gpd______________________________________ In pump type L-60, the impeller diameter was 5 inches; in pump type L-S0, it was 6 inches, and in pump type L-100, it was 6.25 inches. The unactivated or neat polymer is introduced through the premix manifold 26 and into the mixing loop 24 by a variable speed, positive displacement pump 28 which delivers the polymer at a rate which achieves, a range of desired concentrations. Because the centrifugal pump 22 is derated, it causes a desirable mixing shear of the polymer. A calibration column (not shown) is provided to correlate the variable speed pump 28 to its capability to deliver the unactivated polymer at a rate which accurately obtains the desired concentration. The pump 28 is not modified and merely delivers the polymer to the mixing manifold 26. The mixed water and polymer solution is recycled, via loop 24, back through the premix manifold 26 and the booster module (derated centrifugal pump 22) which continues to boost the level of the activation or inversion of the polymer. The final stage of polymer inversion is controlled by the mixing pressure regulator 30. The polymer solution passing through the regulator 30 experiences a sudden and abrupt pressure drop which further inverts the solution. The pressure drop causes a third kind of shear of the polymer. This pressure drop is adjustable and represents an important factor in the development of the inversion of polymer molecules. The pressure regulator 30 is a standard commercial item. More specifically, the mixing pressure regulator 30 is provided in the mixing loop to enable a discharge of the inverted polymer at a desired level of activation while, maintaining a net positive suction head in the centrifugal pump to prevent cavitation. Once the desired output rate and level of inversion is selected, the mixing pressure regulator 30 automatically compensates for any surging or ebbing flow which is attendant upon changes in the output flow rate. Thus pressure regulator 30 maintains the desired level of inversion in the centrifugal pump 22. It should now be apparent that the mixing pressure regulator is critical in three areas. It is used to maintain a constant net positive discharge head on the booster module, which is an important consideration in the hydraulics of the system. It controls the amount of recycling which occurs in the recycle stage. It provides a variable pressure drop zone in the final stage and enables the operator to select a proper amount of mixing energy, based on the type and concentration of polymer being processed. The higher solids polymers and higher solution concentrations require more mixing energy than usual. Regulator 30 is set to cause a sudden and abrupt relaxation of pressure, from the pressure in line 60 to or near atmospheric pressure. This sudden and abrupt relaxation causes an effect which is somewhat similar to the aging which occurs in a holding tank in prior art systems. A limiting factor is that the pressure regulator 30 can not be adjusted to operate at any level which causes cavitation in the derated centrifugal pump 22. The inverted polymer is delivered at output 59 for any suitable further use. The solution output of the system with the various pump described above may be as follows: ______________________________________054 AnCAT .13 to 10 gpmL-10 AnCAT 3 to 10 gpmL-20 AnCAT 4 to 20 gpmL-30 AnCAT 4 to 30 gpmL-60 AnCAT 5 to 60 gpmL-80 AnCAT 5 to 80 gpmL-100 AnCAT 5 to 100 gpm______________________________________ The system also has a flow sensor (not shown) which senses the flow rate of the solution in the system. If a low water flow rate condition is sensed, (i.e. a flow below three gallons per minute for the L-10 pump), the system is automatically shut down and alarms are sounded. Further, a compound gauge 61 in the mixing loop provides means for a visual inspection of the operating conditions of the pump. In operation, the invention provides an automatic system for inverting emulsion polymers at desired output rates and desired levels of activation. The system provides homogeneous, inverted, solutions at desired concentrations. The system, in fact, is inexpensive, reliable, and provides variable capabilities which are not offered by other known systems. More particularly, the system takes in polymer at inlet 62 and water at inlet 64. The throttling valve 20 is set to regulate the amount of inflowing water and, therefore, the ratio of water to polymer. By adjusting valve 20 a more highly concentrated polymer solution may be produced. For example, a solution which is 1% polymer may be increased to a solution which is 2% polymer by a suitable adjustment of valve 20. The diameters of the pipes, apertures, impedance of the static mixing device 50, etc. cause an outflow of derated centrifugal pump 22 to divide at point 66. The ratio selected for the division depends upon the nature of the product. In an exemplary system, about 60% of the outflow of derated centrifugal pump 22 passes through pipe 60 and the pressure regulator 30 to the output of the system. The remaining approximately 40% of the outflow from derated centrifugal pump 22 recirculates to the pre-mixing manifold 26, from which, it is fed back at 68 to the derated centrifugal pump 22. Thus, the feedback loop 24, 66, 26, 68, 22 always contains both the combination of a previously mixed solution of water and polymer and a new mixture of fresh stock and a feedback mixture. It should now be clear that the inventive system has four stages: pre-mix, blend, recycling, and final stage. The pre-mix occurs in the mixing manifold 26 when the raw polymer first meets back fed polymer solution. The turbulence caused by baffles 52, 54 (FIG. 3) of the static mixer 50 tends to thoroughly mix the polymer and polymer solution, but the oil carrier suspending the coiled polymer molecule may remain unbroken. The blend stage starts in the centrifugal pump 22 where the oil carrier begins to be or is broken, at a first level of inversion. The recycling stage occurs in the feedback loop 24 where about 40% of the outflow of pump 22 continues to receive an imparted amount of energy to enhance the inversion process. A level of equilibrium and stability is soon reached wherein the majority of the hydrocarbon carrier is emulsified by the time that the outflow reaches the outlet pipe 60, where the polymer is inverted. The final stage occurs when there is a sudden pressure drop in regulator 30 which relaxes the polymer molecule. Then, the similar charges along the long polymer molecule repel each other and cause it to straighten in response to the sudden reduction of pressure in regulator 30. The resulting inverted polymer is delivered from output 59 to any suitable device. The principles and the apparatus described thus far may be expanded and modified to provide systems which are custom designed for inverting various polymers in various electrolytes. These changes are illustrated in FIG. 5 where the format of the piping system has been modified to mix a polymer with, not only water, but also additional chemicals. In this particular example, the polymer is mixed with dimethylamine ("DMA") and formaldehyde. In its pure form, DMA is a highly flammable material which should not be brought into a factory. Therefore, DMA is introduced via a pump 80, the output of which is connected to the water input pipe 64 while it is outside the factory and before it reaches the throttle valve 20. After the DMA is mixed with water, it may be safely pumped into the factory. The formaldehyde may safely be handled within a factory area; therefore, it is introduced via pump 81 which may be at any convenient location. The formaldehyde is injected into the mixture of water and DMA before it reaches the derated centrifugal pump 22 and the polymer. The remainder of the system in FIG. 5 is the same as the system of FIG. 1. Therefore, it will not be described again. The out flow from pressure regulator 30 is a composition comprising a polymer mixed into a carrier of water, DMA, and formaldehyde. FIGS. 6 and 7 shows a practical embodiment of an inventive system which incorporates the principles set forth in FIGS. 1-5. The system 110 is adapted to receive water and neat emulsion polymer in a mixing loop 112 in order to mix and invert the emulsion polymer at desired levels of energy. The system 110 further provides a continuous output of inverted emulsion polymer at desired rates through discharge outlet 114 where a sensor means may sense an active level of the polymer. The mixing loop 112 includes a static mixing manifold or chamber 116 and a booster module or centrifugal pump 118 in fluid communication with each other through conduits 120 and 122. The unactivated or neat polymer is introduced through conduit 124 and into the mixing loop 112, for inversion, in the premix manifold or chamber 116. The water is supplied to a water inlet 126 which is in fluid communication with the mixing loop 112 through conduit 128. Neat polymer is supplied from a source to the conduit 124 through shut-off valve 130 and pump 132. The system 110 is capable of automatically selecting the desired concentration of the inverted polymer once the desired flow rate of water is selected. This is accomplished by motor 134 coupled through gearbox 136 to the pump 132. The motor 134 receives its power from control panel 140 through electrical cable 138. The gearbox 136 enables an adjustment of the polymer feed rate through the pump 132 to the mixing loop 112. The gearbox 136 is calibrated for each polymer which is utilized, because different solution concentrations produce different flow rates, for the same pump speed. The calibration is accomplished by closing shut-off valve 130 and by filling calibration column 142 with the polymer which is to be used. The calibration column 142 supplies its polymer to the pump 132. By correlating the rate of decrease of polymer in the column 142 to an adjustment member 144 on the gearbox 136, the polymer is delivered at a selected rate to the mixing loop 112. The shut-off valve 130 can then be opened to supply polymer at the desired rate. Gauges 146 and 148 are coupled to the inlet and discharge sides, respectively, of the pump 132. These gauges provide a visual inspection of proper pump operation. Gauge 146 is a vacuum pressure gauge and indicates suction pressure of the pump. Gauge 148 monitors the discharge pressure of the pump. High level values on gauge 148 warn of blockage in the pump 132 or in the premix manifold or chamber 116 and lead to a deactivation of the system in order to ascertain and correct the cause of a malfunction. The water is supplied to the mixing loop 112 via the conduit 128, a metering valve 150, and a flow rate indicator 152. The flow rate indicator 152 is calibrated in gallons per minute. By adjusting valve 150, one can select the desired rate of output of inverted polymer solution. The flow rate indicator 152 includes a low flow sensor. When a low flow condition is sensed in the system, an impulse is sent through electrical cable 154 to the control panel 140, which deactivates the system and sounds an alarm to alert an operator. A mixing pressure regulator 156 communicates between the discharge outlet 114 and the mixing loop 112. The pressure regulator 156 contains an adjustment 158 for varying pressure within the mixing loop 112 to achieve a desired level of inversion of the emulsion polymer. The booster module or centrifugal pump 118 supplies a motive force for mixing the polymer and water and for moving it through the mixing loop 112. The centrifugal pump 118 receives its power from the control panel 140 via cable 162. A gauge 164 is provided to visually inspect the operating condition of the pump 118. The gauge 164 is a compound gauge which is coupled to the premix manifold or chamber 116, to indicate the suction pressure of the pump 118. The conduit 120 includes a visual flow indication viewing window, for the mixing loop. Gauge 166 is coupled to the conduit 122 and gives values for the mixing pressure within the mixing loop. The discharge outlet 114 discharges the inverted polymer either to a tank (not shown) or directly to a processing system (also not shown). Cable 168 communicates between the control panel 140 and the tank. When a predetermined level of active solids in the inverted polymer is sensed by a sensor 169 at discharge outlet 114, the control panel 140 deactivates or otherwise controls the system. Once the desired levels of output and energy levels are selected, the system automatically operates the pressure regulator 156 to change the flow rate of the water to maintain the level of pressure in the mixing loop 112 which provides the desired level of the polymer inversion energy. Pressure within the mixing loop 112 dictates how much polymer recirculates, which in turn is directly proportional to the level of inversion energy. Therefore, with an increase in mixing pressure, via the mixing pressure regulator, the pressure in the loop increases which means more polymer recirculation. All of this is carried out by controls in panel 140 acting, in part, responsive to sensor 169. The mixing loop 112 not only provides a balance to achieve a desired output rate and a desired level of inversion energy, but also provides a regulation to prevent a cavitation of pump 118. In order to get a flow rate out of the pump 118, it is necessary to supply it with its net positive suction head ("NPSH ") requirement. Cavitation or a boiling of the liquid occurs if there is a failure to supply the pump 118 with its required NPSH. Therefore the regulator 156 and valve 150 balance the loop 112 and provide variations in the output rate and in the level of inversion energy, within ranges to regulate the NPSH requirement of pump 118. The system is an automatic, efficient, low cost apparatus for mixing and inverting emulsion polymers. More particularly, the system 110 provides an ultimate control over an inverted polymer concentration which is in the range of about 0.10 to 15 percent. Also, the system 110 automatically provides a variable rate output, while maintaining critical mixing pressures for the introduction of controlled mixing energy to the emulsion polymer. Thus, the system may be either shut down or adjusted in response to an output sensor 169 in order to insure a proper inversion level and to maintain quality control. An addition of secondary dilution enables the system to operate in a manner where a relatively small, low volume, low cost system may increase its productive output to match that of a much larger and high cost machine. Also, the secondary dilution enables a system to invert polymers in a manner which is much simpler, straight forward, and easier than was possible heretofore. In fact, it at least theoretically opens the door to an activation of polymers which might not have been subject to proper inversion heretofore. The system described above (FIG. 1) has only a "primary dilution" between the inputs 62, 64 and output 59. The primary dilution results from the mixture of polymer and water in a ratio selected by valve 20. The outflow from pressure regulator 30 may have characteristics which are predetermined by the polymer being activated and the user's needs. If an effort is made to use a simplistic approach of directly producing a 0.1% solution, the raw water or other electrolyte forming the primary dilution would result in "surfactant washout". If an effort is made to simply double the output of the system by running more polymer and water through the system, the controls placed within the system would be overcome thus producing a low quality polymer solution. Heretofore, secondary dilution has been introduced in a manner shown in FIG. 8 which uses the teaching of the polymer inverter of U.S. Pat. No. 4,218,147, which is being used as the basic inversion system. The reference numerals 59, 62, 64 are used to orient FIG. 8 to the system of FIG. 1. It should be understood, however that except for these three reference numerals, the system of FIG. 8 has no relationship to the system of FIG. 1. In FIG. 8, the introduction of a secondary dilution is controlled by two flow rate regulators 200, 202. The secondary water introduced at 204 is automatically held at a first and fixed flow rate by regulator 200. This water is mixed at a "T" fitting with the inverted polymer solution outflow from pipe 59. Fresh water is also added at 208 to the diluted stream. Finally, a fixed rate regulator 202 releases the secondarily diluted solution at outlet 210. The trouble with this system (FIG. 8) is that the already inverted polymer goes through the fixed rate regulator 202. At least some of the time, such a regulator is certain to have a relatively high upstream pressure on one side and a relatively low pressure on the other side with a pressure drop between, which causes some degree of shear and therefore changes the characteristics of the inverted polymer. Thus, it is quite likely that the inverted molecules will break as they pass through regulator 202. It is possible to have this kind of control in a primary loop such as loop 24 (FIG. 1). However, once the polymer leaves the closely controlled primary system, the secondary and tertiary effects of randomly occurring variables make it extremely difficult or impossible to effect the same degree of control. Therefore, as a practical matter, the system of FIG. 8 is either totally useless or too sensitive to provide a reliable operation. FIG. 9 shows the inventive secondary dilution system. Again, the reference numerals 18, 59, 62, 64 are used to help orient the relationship between FIGS. 1 and 9. The primary dilution leg 211 (FIG. 9) couples into the (FIG. 1) system at the premix block 26. The secondary dilution leg 216 couples into the output pipe 59 via a simple "T" coupling. The raw water flow into the FIG. 1 system is via a primary dilution circuit 211 including a flow meter 212, the throttle valve 214, and a maximum flow rate valve 216, which may be a commercial product sometimes identified as a "Dole" valve. The secondary dilution circuit 216 is as nearly identical as possible to the primary circuit 211, including a flow meter 218, a throttle valve 220, and a maximum flow rate valve 222. In addition, a pilot operated regulator 224 is coupled between the throttle valve 220 and the maximum flow rate valve 222. A pilot line 226 couples the primary dilution circuit 211 to the secondary dilution circuit 216. Thus, it is seen that primary circuit 211 and secondary circuit 216 may be described as a pair of parallel legs having a pilot controlled regulator for delivering the water or other electrolyte fluid to the polymer inverting system in a fixed ratio despite fluctuations. A conventional regulator 224, such as one made by the Watts Regulator Company of Andover, Mass., has a double chamber sealed by a diaphragm which is exposed on one side to the pressure of a mainstream of water flow. In another chamber is a spring which normally presses against the other side of the diaphragm. If the pressure in the mainstream chamber exceeds the bias of the spring, the diaphragm moves in one direction. If the spring bias exceeds the pressure in the mainstream chamber, the diaphragm moves in the other direction. Depending upon the direction and amount of the diaphragm movement, the mainstream flow rate is increased or decreased to maintain a closely regulated uniformity of the mainstream flow. In the pilot flow regulator 224 of the inventive system (FIGS. 9A, 11), the construction is similar except there is no spring. Instead, a pilot line tube 226 is connected to a control chamber Cl in regulator 224 of the primary dilution circuit 211. The mainstream flows through another chamber C2. If the pressure in the primary circuit 211 is higher than the pressure in the secondary circuit 216, the diaphragm D moves in on direction. If it is less, the diaphragm moves in the other direction. The flow of the mainstream is controlled by the movement of the diaphragm. Hence, the pilot regulator 224 keeps the same relationship between the pressures in the primary and secondary circuits 211, 216. This means that the system output at 230 always has the same ratio of primary and secondary dilution water. The various flow meters and maximum valves are set to establish maximum dilution values. If, for example, the throttle valve 214 is opened or closed a little to simulate changes in water pressure, the pilot operated regulator 224 is observed as immediately opening or closing the secondary dilution circuit 216 in order to restore the preselected ratio of water flowing in the two circuits 211, 216. Thus, an operator may adjust the throttle valve 214 to provide a proper amount of water without unbalancing the system. This greatly simplifies operational procedures. Also, the regulator 224 may respond to and correct for any primary water delivery fluctuation which the system may encounter. First, the upstream source of water 64 may fluctuate. Second, something within the system (FIG. 1) may cause a fluctuation. Third, something downstream, after output 230, may cause an increase or decrease of back pressure upon the system to cause primary water fluctuations. The throttle valves 214, 220 of FIG. 9B have a servo valve controllers 219, 221 (known in the trade as "valve actuators"). These actuators respond to signals transmitted from control circuit 217 to maintain a predetermined relationship between the flow in the primary and secondary legs 211, 216. Therefore, if for example, the ratio of primary to secondary dilution is set at 2:1, and further if a downstream sensor detects an increase in the concentration of the polymer solution, the sensor sends a signal over wire 223 directing circuit 216 to increase the amount of diluting water. The signals sent from circuit 217 to valve actuators 219, 221 increases the flow rates through valves 214, 220 in a ratio of 2:1. The sensor may be placed anywhere in the system which is representative of the final dilution (percentage of solids and water in the final output of the system). The ratio may also be controlled from a remote location. More particularly, in certain applications the ratio of primary and secondary dilution flows can be critical. For example, in paper making, where polymers are used as retention aids, the final working polymer solution concentration (i.e. after all dilutions are made) must be substantially exact and known in order for the chemical to act favorably on the paper machine. Therefore, a signal processor or operator may control the system. In this instance, the flow meters 212, 218 on each dilution leg is fitted with a flow transmitter which is in communication with a sensing controller 217, Foxboro (Model 761), Foxboro, Mass. Such flow transmitters are standard commercial items available from Hedland of Racine Wis. The sensing controller may be adjusted from a number of outside sources (e.g. local, remote, etc.) to maintain a selected ratio between the primary and secondary dilution legs. Valve actuators 219, 212 (available from Asahi) fitted to throttling control valves 214 and 220 change the flow rates in response to the sensing controllers commands. The operator or signal processor sends suitable signals over wire 223 to control, select, and adjust ratios of the flow from an outside source and through the primary and secondary legs. It is important to note (FIG. 9) that, after inversion, the secondary dilution system does not subject the polymer to any mechanical shear. By an inspection of FIG. 9, it will be seen that an output pipe 59 extends directly from the polymer inverter of FIG. 1 to any suitable activated polymer utilization device without going through any pressure changing devices, such as the regulator 202 of FIG. 8. The system hardware is seen in FIG. 10 (a side elevation) and FIG. 11, (a top plan view). The raw water intake is at 64 (FIG. 11) and the concentrated polymer intake is at 62. The water is taken in through a solenoid controlled valve 20. The polymer concentrate is taken in through a calibration assembly 240 and a booster pump 28. Electric wires are seen in various o places identified as 242. The polymer concentrate is pumped into the pre-mix block 26 via a conduit 244 and returned from the block via conduit 248, both of which are part of the loop 24. A pressure gauge is seen at 61. A manual valve 250 provides for adjusting the pressure setting of the pressure regulator 224. A "T" fitting 252 forms the junction between the water intake 64, and the primary and secondary dilution circuits. The remainder of the hardware may be identified by comparing the reference numbers in FIGS. 8-11. During the course of the operation of devices that mix, blend and invert liquid polymers, it is necessary to isolate concentrated polymer from the dilution water flowing in the mixing system. This isolation is generally accomplished by using a checking device 400 in a supply line 402 extending between the concentrated polymer supply and the mixing system. This checking device can be a swing check valve, a spring loaded ball or popper, or a simple on/off valve. When the check valve fails, the water flows back into the polymer supply lines 402, changing the characteristic of the polymer at some measured threshold valve which could result in the improper preparation of the polymer. A suitable relay (not shown) can be engaged for annunciating when a check valve failure is in progress, and also for shutting down the system. More particularly, check valve 400 prevents a reverse flow of the water through line 402 and back into the concentrated polymer supply source. Under normal circumstances, the check valve may fail from time to time and allow a backflow water seepage to occur. These failures usually result when some form of solid or semi-solid material lodges in the check valve mechanism and stops the valve parts. Such a backflow would lead to a premature wetting of the concentrated polymer which would render the concentrated polymer useless so that it usually has to be discarded. A continued operation of the machine under these conditions usually results in a contamination of the polymer supplies and may cause potential polymer injection pump failures. According to the invention, means are provided for sensing a change in the characteristic between that of the pure concentrated polymer flowing through line 402 and into the mixing device and that of the polymer that is contaminated with back flowing dilution water. After a polymer is wetted, the water or other electrolyte gives greater conductivity (lower resistivity) to the mixture since a concentrated polymer is usually an effective insulator. Additionally, a physical and chemical change in the polymer occurs when the premature wetting of the polymer causes a certain level of inversion to take place. In a preferred embodiment of the invention, the resistivity of the polymer is measured by a device which is comprised of two components, a field sensor and a sensor circuit which measures resistivity. An example of such a circuit is manufactured by Curtis Industries, Milwaukee, Wis. and preferably is identified as Model LCS-10, although other circuits in their LOS or LHS lines may be used. The sensing device is built into a stainless steel tube which is the supply line 402 that interconnects the polymer supply 62 (FIG. 1) and the mixing block 26. A circuit board carrying the sensor circuit 404 is coupled to the stainless steel tube via leads 416, 418 and low voltage electrodes attached to the stainless steel tube. The principle used by this sensor is to determine the conductivity of the neat polymer stream. For most polymers, the conductivity of a polymer solution changes as water, or another electrolyte, is added to it. Thus, since the highly concentrated, high solids neat polymers are relatively non-conductive, it is possible to measure their electrical current carrying capability to determine when they have become contaminated with water. In one system which was actually built and tested the current resistance was measured by an ohmmeter circuit which measured resistivity in the range of O-to-100,000 ohms. Other ranges could also be used. More particularly, the stainless steel tube has two insulation sections 406, 408 which isolate a section 410 of the tube between them. The electrically isolated section 410 doubles as a sensor electrode, the other electrode being the part of the stainless steel tube which is the conduit for the neat polymer being pumped to the premix manifold 26. The polymer is an isolator; therefore, if nothing but polymer appears in the stainless steel tubing extending from pump 28 to block 26, the resistivity between section 410 and tubing 412 is very high. If the check valve 400 is functioning properly, all polymer flow is in the direction of the arrow 414. There is no back flow of water from the mixing block 26 to the polymer pump 28. If the check valve 400 is not functioning properly, there may be a seepage of water from the block 26 upstream (against the direction of the arrow 414) through tube 402 and toward the pump 28. The water conducts electricity and, therefore, the resistivity goes down, the greater the amount of water, the lower the resistance between section 410 and tubing 412. The circuit on card 404 applies a voltage on one of the leads 416, 418 and reads the voltage on the other lead. While it does so, it sees the current flow, if any, between its two leads 416, 418. If the check valve 400 is not functioning properly, water in the mixing loop begins to migrate upstream (toward pump 28). Water conducts electricity. Therefore, the electrical signal which is applied to one of the leads 416, 418 transmitted by the wetted polymer across the insulating barrier 408. The circuit on the printed circuit card 404 is basically an ohmmeter designed to measure the resistance across the insulator barrier 408, and thus the amount of water that is backflowing through the check valve. Once the resistance across the barrier falls below a threshold level, a suitable command signal is sent to the system in order to give an alarm, shut down the system, or the like. In this version, the sensor tube is located between the injection pump head and the check valve. In other versions, it may be located elsewhere. Also, the circuit on board 404 could be an ammeter to measure current or a voltmeter to measure potential difference. Still other techniques could measure upon doppler effect, inductance, capacitance, frequency, or another phenomenon. Another electrode may be attached to another conductive element in communication with the concentrated polymer conduit. The location of the other electrode may vary with the type of polymer used or the point in the system which is to be monitored, e.g. locating the second electrode close to the injection pump head will monitor contaminated polymer as it approaches the pump head. Therefore, the location of the second electrode, (e.g. close to the check valve, or the injection pump, or even the bulk tank supply vessel) is fundamental in determining the point of alarm in the system. The principles of the sensor 402 which are shown in FIG. 10 may be expanded to give more detailed information. For example, in FIG. 10A a third isolator 408a is added to the stainless steel pipe, thereby making two isolated conductive sections 410, 412 which are connected to leads 416, 418, respectively. The process may be expanded so that any suitable member of isolated sections may be provided. This way, the system may monitor the progress of water seeping back toward the source of the polymer. Thus, the system may be adapted to give different command signals depending upon how serious the problem becomes. Ideally, all parts of the conductive conduit should normally be made of similar metals, but this is not necessary. In one embodiment the sensor board has a potentiometer that may adjust the sensitivity of the circuit to enable an operator to compensate for increased or decreased polymer conductivity, dilution water conductivity, or the concentrated polymer conduit's electrical resistivity. Those who are skilled in the art will readily perceive how to modify the invention. Therefore, the appended claims are to be construed to cover all equivalent structures which fall within the true scope and spirit of the invention.

The inventive method inverts and activates polymer, and delivers it to an output at a relatively high concentration of polymer in an electrolyte fluid, such as water. The inversion and activation results from four steps: (1) premixing polymer and a diluent, (2) blending the premixed polymer/diluent in a derated centrifugal pump, (3) recycling a portion of the blended mix, and (4) suddenly relaxing the pressure to relax the polymer in the blended polymer/diluent mixture. A secondary source of the fluid is applied at the output to the high concentration in order to dilute it to a desired level of concentration. A pilot controlled valving system controls the secondary source of the fluid and maintains a uniform dilution despite any fluctuation in the delivery of the fluid to the activating system. A sensor at the output feeds back a control signal to maintain a uniform level of polymer activity in the outflow from the system. A check valve monitoring system gives an alarm if water seeps back toward a source of polymer which is to be activated.

FIELD OF THE INVENTION [0001] The invention relates to a controlling device for controlling a state of an alarm limit of an alarm device. [0002] Further, the invention relates to a patient monitoring apparatus for monitoring a physiological parameter of a patient. BACKGROUND OF THE INVENTION [0003] It is commonly known that a patient monitoring apparatus is used for monitoring a physiological parameter of a patient, in order to continuously supervise a health state of the patient. Usually, the patient monitoring apparatus comprises an alarm device configured for providing an alarm signal in those cases in which a sensed value of the monitored physiological parameter deviates from values of a predefined interval. In particular, an alarm signal is generated in cases in which the sensed value is less than or at most equal to a lower alarm limit and in cases in which the sensed value exceeds an upper alarm limit. The lower and upper alarm limits may depend on the age of the patient, the kind of monitored physiological parameter, and general guidelines defined by a supervision unit owning or operating the patient monitoring apparatus. [0004] It is further known that a supplementary treatment may be administered to the patient during the monitoring of the physiological parameter, in order to guarantee a proper health state of the patient and/or to improve the health state of the patient. The administration of the treatment may influence the sensed value of the monitored physiological parameter of the patient. In particular, the sensed physiological parameter value may decrease or increase, respectively, causing the sensed value of the physiological parameter to be lower than the lower alarm limit or to exceed the upper alarm limit of the alarm device of the patient monitoring apparatus, respectively. Accordingly, the lower and upper alarm limits of the alarm device may represent particularly important parameters during monitoring the patient, since the lower and upper alarm limits may represent safety relevant issues for the patient. [0005] For example, arterial hemoglobin oxygen saturation (SpO2) of a preterm infant may be monitored using a patient monitoring apparatus during the first days after the birth of the infant, in order to guarantee a proper physical development of the infant. A deviation of the oxygen saturation value of the infant from a range of predefined values for a given time may impact the health of the infant. For example, a too low value of the oxygen saturation (hypoxemia) may result in hypoxia of the brain and other organs, which may lead to permanent damage of these organs. For a preterm infant, the lower SpO2 alarm limits of an alarm device may be defined by individual hospital definitions and may correspond to about 88%. [0006] Further, a treatment agent in the form of supplementary oxygen may be supplied to the preterm infant, to ensure a sufficient oxygen saturation value of the infant. On the other side, supplying too much oxygen to the infant may increase the incidence of retinopathy of prematurity (ROP) and lung disease. During a time in which the infant may receive supplementary oxygen, an increased diligence of a caregiver of the infant may be required to prevent diseases of the infant resulting from too high oxygen saturation values. This may be achieved by avoiding oxygen saturation levels in the upper range (hyperoxemia). Typically this may be accomplished by using the upper SpO2 alarm limit of an alarm device. The upper SpO2 alarm limits of an alarm device may be defined by individual hospital definitions and may correspond to about 94%, a saturation value which is of no concern when the infant is breathing normal air. [0007] By using the standard low and high SpO2 alarm limits, it may happen that nuisance alarm signals are triggered by a sensed hemoglobin oxygen saturation value exceeding the upper alarm limit although no supplementary oxygen is supplied to the infant. [0008] In order to adapt the personal monitoring of a caregiver of the infant to the fact whether the infant is receiving oxygen or not, it is known from the medical survey “Which oxygen saturation level should we use for very premature infants? A randomized controlled trial”, BOOSTII, NHMC Clinic Trials Center, 24 Aug. 2006, that the upper alarm limit of an alarm device shall be set to 94% in case a monitored infant receives supplementary oxygen and that the upper alarm limit of the alarm device shall be switched off or deactivated in cases in which the infant is exposed to air. [0009] Further, it is known from NICU Specific policies “Pulse Oximetry”, Proc17.23, issued in July 1992 and revised in July 2000, that a high Sp02 alarm is to be deactivated in cases in which the patient is exposed to room air or is a full term infant and that a high Sp02 alarm is to be set to 98% in cases in which the patient is a preterm infant and is receiving oxygen. [0010] However, such a manual controlling of the upper alarm limit may result in a time consuming supervision of the infant, since the caregiver of the infant may have to permanently monitor the individual treatment of the infant. Further, a potential risk of health threats of the infant may be increased using the above described controlling of the state of the upper alarm limit of the alarm device. SUMMARY OF THE INVENTION [0011] It may be an object of the invention to provide an improved controlling of an alarm limit of an alarm device which may be used during monitoring a physiological parameter of a patient. [0012] In order to achieve the object defined above, a controlling device for controlling a state of an alarm limit of an alarm device, and a patient monitoring apparatus for monitoring a physiological parameter of a patient are provided. [0013] According to an exemplary aspect of the invention, a controlling device for controlling a state of an alarm limit of an alarm device is provided, wherein the alarm device is configured for generating an alarm signal in association with a monitored physiological parameter of the patient, wherein the alarm limit triggers the generation of the alarm signal, the controlling device comprising a receiving unit configured for receiving information indicating an administration of a treatment to the patient, a determining unit configured for determining whether the treatment is administered to the patient based on the received information, and a controlling unit configured for controlling the state of the alarm limit based on a result of the determination of the determining unit. [0014] According to another exemplary aspect of the invention, a patient monitoring apparatus for monitoring a physiological parameter of a patient is provided, the patient monitoring apparatus comprising an alarm device configured for generating an alarm signal in association with the monitored physiological parameter of the patient, and a controlling device configured for controlling a state of an alarm limit of the alarm device as defined as above. [0015] According to another exemplary aspect of the invention, a method of controlling a state of an alarm limit of an alarm device is provided, wherein the alarm device is configured for generating an alarm signal in association with a monitored physiological parameter of a patient, wherein the alarm limit triggers the generation of the alarm signal, the method comprising receiving (particularly by a receiving unit of a controlling device configured for controlling a state of an alarm limit of the alarm device) information indicating an administration of a treatment to the patient, determining whether the treatment is administered to the patient based on the received information (particularly by a determining unit of the controlling device), and controlling the state of the alarm limit based on a result of the determination of the determining unit (particularly by a controlling unit of the controlling device). [0016] According to another exemplary aspect of the invention, a computer-readable medium is provided, in which a computer program for controlling a state of an alarm limit of an alarm device is stored, which computer program, when being executed by a processor, is configured to carry out or control a method of controlling a state of an alarm limit of an alarm device as defined above. [0017] According to another exemplary aspect of the invention, a program element is provided, which program element, when being executed by a processor, is configured to carry out or control a method of controlling a state of an alarm limit of an alarm device as defined above. [0018] In the context of the present application, the term “alarm limit of an alarm device” may particularly denote a numerical boundary (value) of an interval being defined in the alarm device comprising a lower numerical boundary (value) and an upper numerical boundary (value). In particular, the values of the upper and/or lower numerical boundaries of the interval may be defined or selected in accordance with a monitored physiological parameter of a patient. In particular, in cases in which a sensed physiological parameter value of the patient may correspond to a value outside of the interval, particularly may be lower than the lower alarm limit or may exceed the upper alarm limit, the alarm device may generate an alarm signal. [0019] The term “state of the alarm limit” may particularly denote a status of an operational mode of the alarm limit and/or a value of the alarm limit associated with the generation of the alarm signal. [0020] The term “physiological parameter” of a patient may particularly denote a physical characteristic of the patient, wherein a value of the physiological parameter may indicate a health state of the patient. [0021] According to the exemplary aspects of the invention, an automatic control of a state of an alarm limit associated with a monitored physiological parameter of a patient may be provided. The control of the state of the alarm limit may be based on the fact whether a (particularly supplementary) treatment may be administered to the patient, which may influence the sensed value of the monitored physiological parameter of the patient. [0022] In particular, as the state of the alarm limit of the alarm device may be automatically controlled, a monitoring of the patient may be less time-consuming in comparison with a manual controlling of the alarm limit of the alarm device. Accordingly, a caregiver of the patient may have much time at his or her disposal usable for other patients, and a hospital service may significantly improve. [0023] In particular, basing the controlling on a result of the determination of the determining unit whether a treatment may be administered to the patient but not on a sensed value of the monitored physiological parameter of the patient may reduce an inaccurate controlling of the state of the alarm limit, since measuring errors of the sensed value may not impact the controlling of the state of the alarm limit. Thus, safety of the monitored patient may be significantly increased. [0024] In particular, failures caused by an improper manual controlling of the alarm limit of the alarm device may significantly decrease. In particular, in cases in which a caregiver of the patient may set the alarm limit of the alarm device in a deactivated or less sensitive state and may forget to set the alarm limit of the alarm device in an activated or more sensitive state when a treatment condition of the patient may have been changed may be prevented. Thus, a safety of the patient may further increase, as potential health threats of the patient may be reduced. [0025] In particular, the controlling device may allow for an accurate and timely adjusted control of the state of the alarm limit of the alarm device, since changes in a treatment condition of the patient may be automatically accounted for. [0026] In particular, disturbances arising from unnecessary generations of nuisance alarm signals in cases in which no treatment may be administrated to the patient may be prevented. [0027] Next, further exemplary embodiments of the controlling device for controlling a state of an alarm limit of an alarm device will be explained. However, these embodiments also apply to the respective patient monitoring apparatus, the respective method, the respective computer-readable medium, and the respective program element. [0028] The alarm limit may comprise at least one of a lower alarm limit of the alarm device and an upper alarm limit of the alarm device. In particular, controlling the lower and upper alarm limits may impact the interval of values between the lower and upper alarm limits which may not trigger the generation of the alarm signal. [0029] The information may comprise at least one of an indication indicating whether the treatment may be administered to the patient, and a value indicating the amount or level of the treatment administered to the patient. In particular, the indication that the treatment is not administered to the patient may comprise zero information, for example in terms of a message having no content. Thus, the controlling device may be adapted for operating on various kinds of information, thereby being easily integratable in already existing patient monitoring apparatuses and/or central surveillance systems installed in hospitals or doctor's offices. In particular, basing the determination on the indication whether the treatment may be administered to the patient may allow for a very easy determination rule which may be less error-prone, resulting in a significantly improved accuracy of an operation of the controlling device. [0030] In particular, the information may be generated by an another device, particularly a treatment administration device being connectable to the controlling device or the patient monitoring apparatus, based on an actual execution of the administration of the treatment to the patient and/or may be inputted by a caregiver of the patient into the controlling device, the patient monitoring apparatus and/or another input device connectable to the controlling unit. In particular, the controlling device and/or the patient monitoring apparatus may comprise a respective input unit, for example, a keyboard. [0031] The determining unit may be configured for comparing the received value with a threshold value, wherein the determining unit may be configured for determining whether the treatment may be administered to the patient based on the comparison. Thus, an accuracy of an operation of the controlling device may be enhanced, since the determination whether the treatment may be administered to the patient or not may be based on a numerical determination. Further, a respective determination algorithm may be easily definable. [0032] In particular, the determining unit may be configured for determining that the treatment may be administered to the patient if the received value may exceed the threshold value and for determining that the treatment may not be administered to the patient if the received value may be at most equal to the threshold value. In particular, the determining unit may be configured for determining that the treatment may be administered to the patient if the received value may not exceed the threshold value and for determining that the treatment may not be administered to the patient if the received value may exceed the threshold value. This measure may provide a particularly simple determination algorithm which may be, for example, easily integrated in already present operational functions of a controlling device. [0033] In particular, the state of the alarm limit may comprise an activated state and a deactivated state, wherein the activated state may be associated with the alarm device generating the alarm signal and the deactivated state may be associated with the alarm device not generating the alarm signal. Thus, the controlling device may be configured for controlling whether the alarm device may generate an alarm signal or not, in order to indicate whether a sensed value of a monitored physiological parameter may be lower or may exceed an alarm limit of the alarm device. [0034] The controlling unit may be configured for at least one of setting the alarm limit in an activated state, for setting the alarm limit in a deactivated state, or setting a value of the alarm limit to another value based on the result of the determination of the determining unit. In this context, the terms “activated state” and “deactivated state” may correspond to the terms “activated state” and “deactivated state” as explained above. In particular, setting the alarm limit in an activated state may be executed by setting a value of the alarm limit to the previously used or defined value of the alarm limit. In particular, setting the alarm limit in a deactivated state may be executed by setting a value of the alarm limit to another value. In particular, the another value selected by the controlling unit may correspond to a value which may be sufficiently different from the numerical boundary value of the alarm interval of the alarm device (for example, sufficiently high in a case of the upper alarm value or sufficiently low in a case of the lower alarm limit) such that no alarm signal may be generated. In particular, the another value of the lower alarm limit may be selected to be (about) 0.1 or a suitable numerical value corresponding to a virtual physiological parameter value of about 10%. In particular, the another value of the upper alarm limit may be selected to be (about) 1 or a suitable numerical value corresponding to a virtual physiological parameter value of about 100%. In particular, setting the value of the alarm limit to another value of the alarm limit may result in the alarm device being less or more sensitive to the monitored physiological parameter or to be sensitive to different values of the monitored physiological parameter. In particular, the controlling unit may be configured for setting the alarm limit to the another value without changing the status of the operational mode, particularly the activated or deactivated states, of the alarm limit. In particular, in a case in which the controlling device is configured for controlling the lower and upper alarm limits of the alarm device, setting the values of the lower and upper alarm limits to another values may change the interval of the alarm device which may not trigger the generation of the alarm signal. These measures may allow for adjusting a controlling of the state of the alarm limit to a particular treatment condition of the monitored patient in order to, for example, increase (particularly extend) or decrease (particularly reduce) the range of sensed values of the monitored physiological parameter which may not trigger the alarm signal, completely change the range of sensed values of the monitored physiological parameter which may not trigger the generation of the alarm signal, adjust (particularly extend) the value of the alarm limit to potentially more safety relevant, critical values of the physiological parameter, or change the value of the alarm limit to different values of the physiological parameter of a patient which may be expected owing to the treatment administered to the patient. [0035] In particular, the controlling unit may be configured for selecting the another value based on the kind of the treatment administered to the patient, thereby the controlling unit may be enabled for automatically changing the value of the alarm limit without requiring an additional specification of the another value, for example, by a caregiver of the patient. [0036] In particular, the value and/or the another value of the alarm limit may be definable by a caregiver prior to the use of the controlling device (for example, via an input unit of the controlling device), thereby providing a single controlling device which may be usable in association with monitoring different physiological parameters and/or with different patients. [0037] In particular, the value and/or the another value of the alarm limit may be predetermined for the controlling device, thereby providing different controlling devices each of which may be usable in association with monitoring a different one physiological parameter and/or with a different one patient. [0038] In particular, the controlling unit may be configured for setting the alarm limit in the activated state if the treatment may be administered to the patient and for setting the alarm limit in the deactivated state if the treatment may not be administered to the patient. Thus, an alarm signal may only be generated in those cases in which a supplementary treatment may be administered to the patient, which administration may influence a sensed value of the monitored physiological parameter of the patient and thus may cause potential health threats for the monitored patient. Accordingly, the safety of the monitored patient may be guaranteed for those treatment conditions which may endanger the health state of the monitored patient. Further, unnecessary disturbances of a caregiver of the patient which may be caused by nuisance alarm signals generated in cases in which no supplementary treatment may be administered to the patient may be prevented. Further, in cases in which a caregiver of the patient may have manually set the alarm limit in the deactivated state and may have forgotten to reactivate the alarm limit as a treatment may be now administered to the patient, the controlling device may automatically account for the changed treatment condition of the patient, thereby increasing a safety of the patient. [0039] The controlling unit may be configured for controlling the state of the alarm limit in a timely limited way (particularly for a predetermined time period). In particular, the controlling unit may be configured to automatically set the state of the alarm limit of the alarm device in a (default) state associated with a time prior to the executed controlling or in an additional state being defined by a caregiver prior to the executed controlling. In particular, the caregiver may define a particular value of the alarm limit to which the alarm limit may be set after the timely controlling. In particular, this defined value may be different from the (original) value of the alarm limit before the executed controlling. Accordingly, the controlled alarm limit may fall back after a time period into the previous state of the alarm limit which may be associated with a status in which (it may be assumed that) the treatment may not be administered to the patient. In particular, the time period after which the controlling may be finished may be selected according to a time scheme of an execution of the administering of the treatment to the patient. Thus, this kind of controlling may account for a timely limited administration of a treatment to the patient. In particular, combining this measure with the information being manually inputted into a respective device may avoid a generation of nuisance alarms during an administration of the treatment to the patient and meanwhile may not compromise a safety of the patient by ensuring that a particularly time-limited treatment administered to the patient may not cause the alarm limit to be permanently controlled in case the caregiver of the patient may forget to manually input further information whether a treatment may be administered to the patient or may re-control (particularly re-activate) the alarm limit of the alarm device. [0040] The controlling unit may be configured for controlling at least one of a display of an indication indicating the state of the alarm limit and a display of an indication indicating whether the treatment may be administered to the patient. Thus, an additional, manually controllable supervision of the state of the alarm limit as well as of the treatment condition of the patient by a caregiver of the patient may be provided such that a caregiver of the patient may be able to personally control the state of the alarm limit of the patient, in order to check a proper operation of the controlling device. [0041] In particular, the controlling of the display of the indication indicating the state of the alarm limit may be based on controlling of displaying or not displaying an indication indicating the value of the alarm limit and/or on controlling of displaying an additional (particularly text-based) indication comprising, for example, the content “Activated state” or “Deactivated state”. [0042] In particular, the controlling of the display of the indication whether the treatment may be administered to the patient may be based on controlling of displaying a (particularly text-based) indication comprising the content “Supplementary treatment” and “No supplementary treatment”. In particular, the controlling of the display of the indication indicating whether the treatment may be administered to the patient may be based on controlling a display of a color of an indication indicating a monitored value of the physiological parameter, wherein a first color may correspond to the treatment being administered to the patient, and a second color may correspond to the treatment being not administered to the patient. For example, the first color may be a regularly used color when displaying the sensed value of the physiological parameter, and the second color may be red. [0043] In particular, the controlling unit may be configured for controlling the display of the indication indicating the state of the alarm limit and the display of the indication indicating whether the treatment may be administered to the patient simultaneously or (particularly immediately) subsequently to the controlling of the state of the alarm limit. Thus, the display of the indication indicating the state of the alarm limit and the indication indicating whether the treatment may be administered to the patient may always correspond to the actual state of the alarm limit and the actual treatment condition of the patient, respectively. [0044] In particular, the controlling device may comprise a respective display unit and/or may be connectable to a display unit of a patient monitoring apparatus and/or of a respective central surveillance system particularly comprising the patient monitoring apparatus, wherein the controlling unit may be configured for controlling a display of at least one of the latter mentioned display devices. [0045] In particular, in order to control the display of at least one of the indication indicating the state of the alarm limit and the display of the indication indicating whether the treatment may be administered to the patient, the controlling unit may be configured for generating respective control signals for at least one of the latter mentioned display devices. [0046] In particular, additionally or alternatively, the controlling unit may be configured for controlling at least one of an audio notification notifying the state of the alarm limit and a notification of an indication indicating whether the treatment may be administered to the patient in an audible way. [0047] The physiological parameter of the patient may comprise a (arterial) hemoglobin oxygen saturation (SpO2) of the patient (particularly measured in units of fractions of 1 or in percentage or “%”), an oxygen partial pressure (pO2) of the patient (particularly measured in units of “mmHg”), a transcutaneously measured oxygen partial pressure (tpO2) of the patient (particularly measured in units of “mmHg”), a (particularly invasively monitored arterial) blood pressure of the patient (particularly measured in units of “mmHg”), a heart rate of the patient (particularly measured in units of beats per minute (BMP)), a pulse rate of the patient (particularly measured in units of impulses per minute), a respiratory rate of the patient (particularly measured in units of respiration acts per minute or second), a respiratory interval of the patient, a capnography parameter of the patient (particularly a concentration of carbon dioxide (CO2) in the respiratory gas measured in units of fractions of 1 or in percentage or a partial pressure of carbon dioxide (CO2) in the respiratory gas measured in units of “mmHg” or Pascal), or a (body) temperature of the patient (particularly measured in units of degree Celsius). These parameters may correspond to conventionally monitored physiological parameters of hospitalized patients in intensive care units, floor units or step-down units of a hospital, thereby the controlling device and the patient monitoring apparatus being versatile usable. [0048] The treatment may comprise a treatment agent which may be supplied to the patient. Here, the term “treatment agent” may particularly denote a gaseous, fluid, or solid agent or a mixture of a gaseous, fluid and/or solid supplementary agent(s) supplied to a patient. In particular, supplying a treatment agent to a patient may impact, particularly increase or decrease, a sensed value of a monitored physiological parameter, thereby triggering a generation of an alarm signal by the alarm device. [0049] The treatment agent may comprise supplementary oxygen or a vasodilatation drug. In particular, in a case of monitoring hemoglobin oxygen saturation, an oxygen partial pressure or a transcutaneously measured oxygen partial pressure of a patient, the treatment agent may correspond to supplementary oxygen, whereas, when monitoring a blood pressure of the patient, the treatment agent may correspond to a vasodilatation drug. These commonly used treatment agents may precisely indicate a potential health risk of the monitored patient. [0050] In particular, the information indicating the supply of supplementary oxygen may comprise a “fraction of inspired oxygen” (FiO2) of a gaseous mixture or a respective value thereof which may be particularly measured in units of fractions of 1 or in percentage or “%”. In particular, a FiO2 value corresponding to room air may be 0.21 or 21%. In particular, the respective FiO2 indication indicating the supply of the supplementary oxygen may comprise the particular value or the content “Supplementary oxygen” or “Room air”. In particular, the respective threshold value usable during the determination whether the treatment agent may be supplied to the patient may correspond to a value of (about) 0.21 (corresponding to (about) 21%) being (approximately) equal to a regular amount of oxygen in room air. [0051] In particular, additionally or alternatively, the information indicating the supply of supplementary oxygen may comprise a tidal volume, a minute volume, and a respiration rate. [0052] The treatment may comprise a treatment procedure which may be applied to the patient. Here, the term “treatment procedure” may particularly denote electrical, electromagnetic, radioactive, light, mechanical, pneumatic or hydraulic energy applied to the patient for therapeutic reasons. In particular, applying a treatment procedure on a patient may impact, particularly increase or decrease, a sensed value of the monitored physiological parameter, thereby triggering the generation of the alarm signal by the alarm device. [0053] The treatment procedure may comprise a ventilation, an electro-surgery (for example, electrical cauterization of tissue using an electro-surgery unit (ESU)), (transcutaneous) pacing, intra-aortic pumping (particularly using an intra-aortic balloon pump), suction of an airway of a patient, or therapeutic cooling. In particular, applying ventilation on a patient may impact a respiration of the patient and may thus be associated with a respiration alarm, an apnea alarm or a respiratory rate alarm. In particular, applying electro-surgery or pacing on a patient may impact a heart rate of the patient and may thus be associated with a heart rate alarm. In particular, applying an intra-aortic pumping on a patient may impact a pulse rate of the patient and may thus be associated with a pulse rate alarm. In particular, applying a therapeutic cooling on the patient (also referred to as “Induced Hypothermia”) may impact a (body) temperature of the patient and may thus be associated with a (body) temperature alarm. In particular, applying airway suction on a patient may impact a hemoglobin oxygen saturation of the patient, a carbon dioxide (CO2) content of a blood of the patient, a respiration of the patient and may thus be associated with the SpO2 alarm, a CO2 alarm, or a respiration alarm. In this example, a lower alarm limit of the SpO2 alarm, a CO2 alarm, or a respiration alarm may be decreased or extended but not be set in a deactivated state. [0054] In particular, in a case of monitoring a hemoglobin oxygen saturation of the patient and applying airway suction on the patient, the value of the lower SpO2 alarm limit, and/or the value of the lower CO2 alarm limit may be decreased. In particular, in a case of monitoring a (body) temperature of the patient and applying therapeutic cooling on the patient, the value of the lower and upper (body) temperature alarm limits may be decreased. Here, the respective values may be particularly selected based on a set point of cooling temperature. In particular, in a case of monitoring hemoglobin oxygen saturation of the patient, a CO2 content of a patient blood, or a respiration of the patient, and applying airway suction on the patient, the value of the lower SpO2 alarm limit, the value of the lower respiration rate alarm limit, or the value of CO2 alarm limit may be decreased. [0055] In particular, the receiving unit may be configured for anew receiving information indicating an administration of a treatment to the patient, the determining unit may be configured for anew determining whether the treatment may be administered to the patient based on the received information, and the controlling unit may be configured for anew controlling the state of the alarm limit based on a result of the determination of the determining unit. Thus, the controlling device may be configured for continuously controlling of the state of the alarm limit. [0056] In particular, the controlling device may form part of a patient monitoring apparatus or may represent an individual module being connectable to various (particularly different) kinds of patient monitoring apparatuses, thus representing a retrofitting module for an already existing patient monitoring apparatus. [0057] In particular, suitable embodiments of at least one of the receiving unit, the determining unit, and the controlling unit may correspond to one or more processors comprising integrated circuits having suitable electronic components such as power supply units, diodes, transistors, integrators, and/or logical components such as AND-, OR-, or NOR-gates. In particular, the receiving unit may be embodied as an interface module or an Input/output-port of a processor. [0058] Next, further exemplary embodiments of the patient monitoring apparatus for monitoring a physiological parameter of a patient will be explained. However, these embodiments also apply to the respective controlling device, the respective method, the respective computer-readable medium, and the respective program element. [0059] In particular, the patient monitoring apparatus may be connectable to a sensing device (or more sensing devices) configured for sensing a value of the (more) physiological parameter(s) of the patient, wherein the alarm device may be configured for generating the alarm signal based on the sensed value(s). Thus, the patient monitoring apparatus may be usable in association with monitoring various physiological parameters. [0060] In particular, alternatively or additionally, the patient monitoring apparatus may further comprise a sensing device configured for sensing a value of the physiological parameter of the patient, wherein the alarm device may be configured for generating the alarm signal based on the sensed value. Such a patient monitoring apparatus may represent a self-contained apparatus being installable in various kinds of treatment environments without the need of further devices. [0061] The patient monitoring apparatus may further comprise a display device configured for at least one of displaying an indication indicating the state of the alarm limit, and for displaying an indication indicating whether the treatment may be administered to the patient. Thus, a visualization of parameters relevant for the health state of the patient may be provided particularly to the caregiver of the patient, thereby the caregiver being able to additionally personally control a proper operation of the control device and the patient monitoring apparatus. Thus, the safety of the patient during the monitoring may be increased. [0062] The patient monitoring apparatus may be connectable to another display device configured for at least one of displaying an indication indicating the state of the alarm limit, and for displaying an indication indicating whether the treatment is administered to the patient. Such a display device may represent a remote display device of a central surveillance system which may particularly comprise a plurality of patient monitoring apparatuses. [0063] The patient monitoring apparatus may further comprise or may be connectable to another sensing device configured for sensing a value of the treatment administered to the patient. Thus, the patient monitoring apparatus may represent a self-contained system which may not rely on supplementary information provided by further devices. BRIEF DESCRIPTION OF THE DRAWINGS [0064] The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited. [0065] FIG. 1 shows a patient monitoring apparatus according to an exemplary embodiment of the invention. [0066] FIG. 2 shows a display provided by a display unit of the patient monitoring apparatus of FIG. 1 DETAILED DESCRIPTION OF EMBODIMENTS [0067] The illustration in the drawing is schematic. It is noted that in different Figures, similar or identical elements are provided with the same reference signs or with reference signs, which are different from the corresponding reference signs only with a first digit. [0068] FIG. 1 shows a patient monitoring apparatus 100 according to an exemplary embodiment of the invention. The patient monitoring apparatus 100 is used for monitoring the arterial oxygen saturation of a preterm infant and for invasively monitoring an arterial blood pressure of the preterm infant. The patient monitoring apparatus 100 is configured as IntelliVue Patient Monitor manufactured by Philips and is installable in a Neonatal Intensive Care Unit of a hospital. The patient monitoring apparatus 100 comprises a housing 102 , in which two interfaces 104 , 106 , an alarm device 108 configured for generating an alarm signal in association with the monitored arterial oxygen saturation and the arterial blood pressure of the infant, a controlling device 110 configured for controlling a state of alarm limits of the alarm device 108 , and a display device 112 is accommodated. [0069] The interfaces 104 , 106 are configured for providing a connection to further electronic components. [0070] The alarm device 108 comprises a loudspeaker 114 configured for announcing an alarm signal in response to a sensed arterial oxygen saturation value or a sensed arterial blood pressure value of the infant. [0071] The alarm device 108 comprises lower and upper limits associated with the arterial oxygen saturation and the blood pressure such that a respective alarm signal is provided by alarm device 108 in cases in which the sensed values of the arterial oxygen saturation and the arterial blood pressure are lower or higher than the upper and lower limit values defined in the alarm device 108 . The lower and upper alarm limits associated with the arterial hemoglobin oxygen saturation are 88% and 94%, and the lower and upper alarm limits associated with the arterial blood pressure are 65 and 110, respectively. [0072] The display device 112 is configured for displaying a sensed value of the hemoglobin oxygen saturation, a sensed value of the arterial blood pressure, and the upper and lower alarm limit associated with the monitored arterial hemoglobin oxygen saturation and the alarm limits associated with the monitored arterial blood pressure. Further information which may be displayed by the display device 112 , 144 will be explained with reference to FIG. 2 . [0073] A first sensing device 116 is configured for sensing the arterial oxygen saturation of the monitored infant and is connected to the interface 104 of the patient monitoring apparatus 100 via a first cable 118 . The sensing device 116 is configured as a foot sensor forming part of a pulse oximetry device accommodated in the housing 102 of the patient monitoring apparatus 100 . A second sensing device 120 is configured for invasively sensing the arterial blood pressure of the infant and is connected to the interface 104 of the patient monitoring apparatus 100 via a second cable 122 . The sensing device 120 is configured as a hypodermic needle being accommodatable into an artery of the infant, connected to a pressure transducer via a fluid filled line. A respective blood pressure measuring device is accommodated in the housing 102 of the patient monitoring apparatus 100 . [0074] The patient monitoring apparatus 100 is further connectable to a treatment agent supply device 124 in the form of a combined ventilator and drug reservoir. The treatment agent supply device 124 is configured for supplying supplementary oxygen to the infant via a respiratory element 126 and a respective tube 128 . An injection needle 130 is connected to the treatment agent supply device 124 via a tube 132 such that a vasodilatation drug is injectable in the body of the infant using titration techniques. Further, the treatment agent supply device 124 comprises a keyboard 134 via which an operator may input a value corresponding to an amount of supplied supplementary oxygen and an amount of the supplied vasodilatation drug. [0075] The patient monitor apparatus 100 is connected via a module 136 to the treatment agent supply device 124 such that a data exchange between the treatment agent supply device 124 and the patient monitoring device 100 is mediated by the module 136 . The module 136 is configured as a commercially available VueLink and/or IntelliBridge Interface Module manufactured by Philips. In particular, information pertaining to whether supplementary oxygen is supplied to the infant and/or the inputted value of the amount of the vasodilatation drug supplied to the infant is transferable from the treatment agent supply device 124 to the interface 104 of the patient monitoring apparatus 100 via the module 136 . The connection between the treatment agent supply device 124 and the module 136 and between the module 136 and the patient monitoring device 100 is accomplished via cables 138 and 140 , respectively. [0076] The patient monitoring apparatus 100 forms part of a central surveillance system 142 which comprises up to 16 patient monitoring apparatuses similar to the patient monitoring apparatus 100 and a central display device 144 arranged at a remote place, for example, in a nurses' room. The central display device 144 is connected to the interface 106 of the patient monitoring apparatus 100 via a cable 145 and the other patient monitoring apparatuses. The central surveillance system is configured as Philips Information Center (PIC). [0077] Alternatively, a communication between the patient monitoring apparatus 100 and the display device 144 of the central surveillance system 142 may be based on a wireless communication. [0078] In the following, the control device 110 of the patient monitoring apparatus 100 will be described in more detail. [0079] The controlling device 110 is configured for controlling the state of the upper alarm limit of the alarm device 108 associated with the measured oxygen saturation and the upper and lower alarm limits of the alarm device 108 associated with the measured arterial blood pressure. The controlling device 110 comprises a receiving unit 146 , a determining unit 148 , a controlling unit 150 , and a sending unit 152 . A constructive implementation of the controlling device 110 may comprise integrated circuits having suitable electronic components accomplishing the functions of the individual units. [0080] The receiving unit 146 is adapted for receiving a sensed value of the arterial hemoglobin oxygen saturation of the infant, a sensed value of the arterial blood pressure of the infant, an information containing the FiO2 value, and the indication indicating whether the vasodilatation drug is supplied to the infant or not. A connection between the receiving unit 146 and the interface 104 is wire-based and is indicated by the double-ended arrow 154 . [0081] The determining unit 148 is configured for determining whether the supplementary oxygen and/or the vasodilatation drug is supplied to the infant based on the information received from the receiving unit 146 using the following algorithms: When receiving a Fi02 value indicating the present amount or percentage of oxygen in the gaseous mixture supplied to the infant, the determining unit 150 is configured for determining that supplementary oxygen is supplied to the infant in case the value received from the treatment agent supply device 124 exceeds a predefined threshold value. Accordingly, in case the received value is below or is equal to the threshold value, the determining unit 150 is configured for determining that supplementary oxygen is not supplied to the infant. The threshold value is independent of the age of the infant and is selected to be 0.21. Further, in case the indication received from the treatment agent supply device 124 indicates that a vasodilatation drug is supplied to the infant, the determining unit is configured for determining that the vasodilatation drug is supplied to the infant. Accordingly, in case the indication received from the treatment agent supply device 124 indicates that no vasodilatation drug is supplied to the infant, the determining unit is configured for determining that the vasodilatation drug is not supplied to the infant. Instead of executing the latter described determination, the determining unit 148 may also simply process the received indication and passes suitable information, for example in a different format, to the controlling unit 150 . [0082] The controlling unit 150 is configured for executing the controlling of the state of the upper alarm limit of the alarm device 108 associated with the arterial oxygen saturation and the alarm limits of the alarm device 108 associated with the arterial blood pressure based on the result of the determination executed by the determination unit 148 and uses the following algorithms: In case the determination results in that supplementary oxygen is not supplied to the infant, i.e. the infant is exposed to regular air, the upper alarm limit associated with the oxygen saturation is set in its deactivated state by switching off the upper alarm limit. In case the determination results in that supplementary oxygen is supplied to the infant, i.e. the infant is exposed to a gaseous mixture having a FiO2 value higher than 0.21, the upper alarm limit is set in its activated state and thus to its predetermined value of 94% or the value that the caregiver previously had assigned. [0083] The controlling of the upper alarm limit associated with the measured arterial blood pressure uses the following definitions: In case that the vasodilatation drug is supplied to the infant the alarm limits associated with the arterial blood pressure are both decreased in their value. In case that no vasodilatation drug is supplied to the infant the alarm limits associated with the arterial blood pressure of the infant are set to their predetermined values of 65 and 110, respectively, or the values that the caregiver previously had assigned. [0084] Alternatively, the control unit 150 may be configured for setting the upper alarm limit associated with the arterial oxygen saturation to 100%, instead of switching off the upper alarm limit. [0085] The sending unit 152 is configured for providing respective control signals to the alarm unit 114 . A connection between the sending unit 152 and the interface 106 is wire-based and is indicated by the double-ended arrow 156 . [0086] Further, the controlling unit 150 is configured for generating control signals for controlling a display of the display device 144 of the central surveillance system 142 and the display device 112 of the patient monitoring apparatus 100 as will be explained with reference to FIG. 2 . A connection between the sending unit 152 and the display device 112 is also wire-based. [0087] In operation of the controlling device 112 and the patient monitoring apparatus 100 , an infant is connected to the treatment agent supply device 124 via the respiratory element 126 and the hypodermic needle 130 and to the patient monitoring apparatus 100 via the sensing devices 116 , 120 . A caregiver of the infant inputs a numerical value of 0.21 into the keyboard 134 of the treatment agent supply device 124 . Further, the caregiver inputs a value of 5 corresponding to an amount of 5 μg/kg/min of a vasodilatation drug to be supplied to the infant. Accordingly, no supplementary oxygen is supplied to the infant but an amount of 5 μg/kg/min of a vasodilatation drug. [0088] The patient monitoring device 100 receives information about the monitored arterial blood pressure and the monitored arterial oxygen saturation from the sensing devices 116 , 120 . Further, the patient monitoring apparatus 100 may receive information about a tidal volume, a minute volume, and a respiration rate from the treatment agent supply device 124 . [0089] Further, the patient monitoring device 100 receives the information having the content “0.21” and the indication indicating that a vasodilatation drug is supplied to the infant via the module 136 . Accordingly, the state of the upper alarm limit associated with the monitored arterial oxygen saturation and the alarm limits associated with the monitored arterial blood pressure is controlled by the controlling device 110 based on the received information. Here, the determination unit 148 determines that no supplementary oxygen is supplied to the infant but a vasodilatation drug is supplied to the infant. The controlling unit 150 sets the upper alarm limit associated with the arterial oxygen saturation of the infant in its deactivated state but sets the alarm limits associated with the arterial blood pressure of the infant to a lower range of 50 mmHg and 100 mmHg, respectively. Respective information about the supply of supplementary oxygen, the supply of the vasodilatation drug, the upper and lower alarm limits associated with the monitored oxygen saturation, and the monitored arterial blood pressure, the monitored oxygen saturation and the monitored arterial blood pressure are displayed by the display devices 112 , 144 . [0090] Referring to FIG. 2 , a display of the display device 112 will be explained in more detail. This content displayed by the display device 112 and the content displayed by the display device 144 are identical to one another. [0091] The display unit 112 is adapted to display an indication 260 indicating the sensed arterial oxygen saturation value, an indication 262 indicating the state and/or value of the upper alarm limit associated with the oxygen saturation of the infant, an indication 264 indicating the state and/or value of the lower limit of the alarm associated with the oxygen saturation of the infant, and a label indication 266 indicating the kind of displayed information and its unit. The latter described indications 260 - 266 correspond to “99”, “- -”, “85”, and “% Sp02”. Hence, since the upper alarm limit is set in a deactivated state, the indication 262 only indicates the deactivated state by not displaying the value but does not indicate the value of the upper alarm limit. [0092] Further, the display comprises an indication 268 indicating the amount of supplementary oxygen supplied to the infant and a respective label indication 270 indicating the kind and unit of displayed information. As no supplementary oxygen is supplied to the infant, the displayed indication 268 is “- -”. [0093] Further, the display comprises an indication 272 indicating the value of the sensed arterial blood pressure (in the shown embodiment “71”), an indication 274 indicating a value of the upper alarm limit associated with the arterial blood pressure (here “100”), an indication 276 indicating a value of the lower alarm limit associated with the arterial blood pressure (“50”), and a label indication 278 indicating the kind and unit of displayed information (“mmHg SYS”). [0094] The display also comprises an indication 280 indicating the amount of the supplied vasodilatation drug (“5”), and a respective label indication 282 (“μg/kg/min VD”) denoting the kind and unit of displayed information of the indication 280 . [0095] Alternatively, instead of displaying or not displaying the indications 268 , 270 , 280 , 282 , the color of the indication 260 , 272 may be controlled by the controlling unit 112 in that a first color, for example red, may correspond to the fact that supplementary oxygen is supplied to the infant, and a second color, for example black, may correspond to the fact that no supplementary oxygen is supplied to the infant. [0096] Alternatively, instead of displaying the FiO2 value or value indicating the amount of the vasodilatation drug, a simple indication in the form of a text “NO” or “YES”, “Room air” and “Supplementary oxygen” or “Vasodilatation drug” and “No vasodilatation drug” may be displayed. [0097] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the use of the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

A controlling device ( 110 ) is configured for controlling a state of an alarm limit of an alarm device ( 108 ). The alarm device ( 108 ) is configured for generating an alarm signal in association with a monitored physiological parameter of a patient. The alarm limit triggers the generation of the alarm signal. In order to automatically control the state of the alarm limit, the controlling device ( 110 ) comprises a receiving unit ( 146 ) configured for receiving information indicating an administration of a treatment to the patient, a determining unit ( 148 ) configured for determining whether the treatment is administered to the patient based on the received information, and a controlling unit ( 150 ) configured for controlling the state of the alarm limit based on a result of the determination of the determining unit ( 148 ).

This is a continuation of application Ser. No. 842,706, filed Oct. 17, 1977, now abandoned. FIELD OF THE INVENTION This invention relates to navigational equipment and more particularly to hyperbolic navigational equipment utilizing the time difference in the propagation of radio frequency pulses from synchronized ground transmitting stations. BACKGROUND OF THE INVENTION Throughout maritime history navigators have sought an accurate reliable method of determining their position on the surface of the earth and many instruments such as the sextant were devised. During the second world war, a long range radio-navigation system, LORAN-A, was developed and was implemented under the auspices of the U.S. Coast Guard to fulfill wartime operational needs. At the end of the war there were seventy LORAN-A transmitting stations in existence and all commercial ships, having been equipped with LORAN-A receivers for wartime service, continued to use this navigational system. This navigational system served its purpose but shortcomings therein were overcome by a new navigational system called LORAN-C. Presently, there are eight LORAN-C multi-station transmitting chains in operation by 1980. This new navigational system will result in an eventual phase-out of the earlier LORAN-A navigational system. LORAN-C is a pulsed low-frequency (100 kilohertz), hyperbolic radio navigation system. LORAN-C radio navigation systems employ three or more synchronized ground stations that each transmit radio pulse chains having, at their respective start of transmissions, a fixed time relation to each other. The first station to transmit is referred to as the master station while the other stations are referred to as the secondary stations. The pulse chains are radiated to receiving equipment that is generally located on aircraft or ships whose position is to be accurately determined. The pulse chains transmitted by each of the master and secondary stations is a series of pulses, each pulse having an exact envelope shape, each pulse chain transmitted at a constant precise repetition rate, and each pulse separated in time from a subsequent pulse by a precise fixed time interval. In addition, the secondary station pulse chain transmissions are delayed a sufficient amount of time after the master station pulse train transmissions to assure that their time of arrival at receiving equipment anywhere within the operational area of the particular LORAN-C system will follow receipt of the pulse chain from the master station. Since the series of pulses transmitted by the master and secondary stations is in the form of pulses of electromagnetic energy which are propagated at a constant velocity, the difference in time of arrival of pulses from a master and a secondary station represents the difference in the length of the transmission paths from these stations to the LORAN-C receiving equipment. The focus of all points of a LORAN-C chart representing a constant difference in distance from a master and a secondary station, and indicated by a fixed time difference of arrival of their 100 kilohertz carrier pulse chains, described a hyperbola. The LORAN-C navigation system makes it possible for a navigator to exploit this hyperbolic relationship and precisely determine his position using a LORAN-C chart. By using a moderately low frequency such as 100 kilohertz, which is characterized by low attenuation, and by measuring the time difference between the reception of the signals from master and secondary stations, the modern-day LORAN-C system provides equipment position location accuracy within two hundred feet and with a repeatability of within fifty feet. The theory and operation of the LORAN-C radio navigation system is described in greater detail in an article by W. P. Frantz, W. Dean, and R. L. Frank entitled "A Precision Multi-Purpose Radion Navigation System," 1957 I.R.E. Convention Record, Part 8, page 79. The theory and operation of the LORAN-C radio navigation system is also described in a pamphlet put out by the Department of Transportation, U.S. Coast Guard, No. CG-462, dated August, 1974, and entitled "LORAN-C User Handbook". The LORAN-C system of the type described in the aforementioned article and pamphlet and employed at the present time, is a pulse type system, the energy of which is radiated by the master station and by each secondary station in the form of pulse trains which include a number of precisely shaped and timed bursts of radio frequency energy as priorly mentioned. All secondary stations each radiate pulse chains of eight discrete time-spaced pulses, and all master stations transmit the same eight discrete time-spaced pulses but also transmit an identifying ninth pulse which is accurately spaced from the first eight pulses. Each pulse of the pulse chains transmitted by the master and secondary stations has a 100 kilohertz carrier frequency, so that it may be distinguished from the much higher frequency carrier used in the predecessor LORAN-A system. The discrete pulses radiated by each master and each secondary LORAN-C transmitter are characterized by an extremely precise spacing of 1,000 microseconds between adjacent pulses. Any given point on the precisely shaped envelope of each pulse is also separated by exactly 1,000 microseconds from the corresponding point on the envelope of a preceding or subsequent pulse within the eight pulse chains pulses. To insure such precise time accuracy, each master and secondary station transmitter is controlled by a cesium frequency standard clock and the clocks of master and secondary stations are synchronized with each other. As mentioned previously, LORAN-C receiving equipment is utilized to measure the time difference of arrival of the series of pulses from a master station and the series of pulses from a selected secondary station, both stations being within a given LORAN-C chain. This time difference of arrival measurement is utilized with special maps having time difference of arrival hyperbola information printed thereon. These maps are standard LORAN-C hydrographic charts prepared by the U.S. Coast Guard and the hyperbola curves printed thereon for each secondary station are marked with time difference of arrival information. Thus, the difference in time arrival between series of pulses received from a master station and selected ones of the associated secondary stations must be accurately measured to enable the navigator to locate the hyperbola on the chart representing the time difference measured. By using the time difference of arrival information between a master station and two or more secondary stations, two or more corresponding hyperbolae can be located on the chart and their common point of intersection accurately identifies the position of the LORAN-C receiver. It is clear that any inaccuracies in measuring time difference of arrival of signals from master and secondary transmitting stations results in position determination errors. There are other hyperbolic navigation systems in operation around the world similar to LORAN-C, and with which my novel receiver can readily be adapted to operate by one skilled in the art. There is a LORAN-D system utilized by the military forces of the United States, as well as the aforementioned LORAN-A system. Others are DECCA, DELRAC, OMEGA, CYTAC, GEE and the French radio WEB, all of which operate in various portions of the radio frequency spectrum and provide varying degrees of positional accuracy. LORAN-C receiving equipment presently in use is relatively large in size, heavy and requires relatively large amounts of power. In addition, present LORAN-C receivers are relatively expensive and, accordingly, are found only on larger ships and aircraft. Due to the cost, size, weight, and power requirements of present LORAN-C receiving equipment, such equipment is not in general use on small aircraft, fishing boats and pleasure boats. In addition, LORAN-C receiving equipment presently in use required anywhere from five to ten minutes to warm up and provide time difference measurement information. Further, present LORAN-C equipment is rather complex, having many controls, and the operator thereof usually must have some training in the use of the equipment. Thus, there is a need in the art for a new LORAN-C receiver that is small, light in weight, has few controls and is therefore easy to operate by inexperienced people, requires a small amount of electrical power, and is relatively low in cost. Such equipment would fill the needs of those who do not now have LORAN-C receiving equipment. SUMMARY OF THE INVENTION The foregoing needs of the prior art are satisfied by my novel LORAN-C receiver. I eliminate much of the complex and costly automatic acquisition and tracking circuitry in prior art LORAN-C navigation receivers and provide a small, light weight, inexpensive receiver using relatively little electrical power. Four thumbwheel switches on my LORAN-C equipment are used by the operator to enter the group repetition rate information for a LORAN-C chain covering the area within which the LORAN-C equipment is being operated. This information entered via the thumbwheel switches is used by an internal microprocessor to locate the signals from the master and secondary stations of the chosen LORAN-C chain. The receiver of my equipment receives all signals that appear within a small bandwidth centered upon the 100 Khz. operating frequency of the LORAN-C network. A digital register coupled with logic circuitry is then used to continuously check all received signals to search for the unique pulse trains transmitted by the master and secondary stations. The microprocessor internal to my novel LORAN-C equipment analyzes all signals output from the register and logic circuitry indicating that signals from master or secondary stations have been received to first determine if they match the group repetition rate for the selected LORAN-C chain and then to develop a histogram of the time of arrival of the signals from the secondary stations. Once the equipment has approximately located and is receiving the pulse trains from the selected master and secondary stations, the microprocessor causes other circuitry to go into a fine search mode. In the fine search mode the microprocessor disables the equipment from analyzing any signals other than those received within 35 microseconds of the approximate time of arrival of the signals from the secondary stations as determined using the histogram. The microprocessor also enables other equipment to analyze the phase of each pulse and to locate the third cycle zero crossing point of each received pulse. In the event the third cycle zero crossing of a pulse is not located at the approximate time indicated by the microprocessor, the analyzation circuitry indicates to the microprocessor whether to add or subcontract 10 microseconds to the approximate time of arrival and then repeats the analyzation process. This analyzation process and shifting of the approximate search point is repeated until the third cycle zero crossing of the desired pulse of the selected master and secondary station pulse trains is located. Using an accurate crystal controlled clock internal to my novel equipment, the microprocessor then makes accurate time difference of arrival measurements between the time of arrival of signals from the master station of the selected chain and the arrival of the pulse trains from the secondary stations. The equipment operator utilizes other thumbwheel switches to indicate two secondary stations, the time difference of arrival information to be visually displayed. The operator of the LORAN-C equipment utilizes these two read-outs using a LORAN-C hydrographic chart to locate the physical position of the navigation equipment on the surface of the earth. In an alternative embodiment of my invention a front panel keyboard may be utilized rather than thumbwheel switches and the microprocessor can be programmed to perform other functions including, but not limited to, use as a calculator. Other possible uses are limited only by the amount of storage provided within the microprocessor or auxiliary memory adjunct to the processor in a well known manner, and by the imagination of the equipment designer. The operator of my novel LORAN-C navigation receiver can quickly and easily calibrate the receiver master oscillator, unlike prior art receivers. To accomplish this, the operator places the equipment in a calibration mode wherein the output of the oscillator is compared against the group repetition interval [GRI] information which has been entered via the thumbwheel switches. The display is used to indicate to the operator if the equipment is in calibration or requires a simple adjustment by the operator. The Applicant's novel LORAN-C navigation receiver will be better understood upon a review of the detailed description given hereinafter in conjunction with the drawing in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a general block diagram of the Applicant's LORAN-C navigation receiver; FIG. 2 shows the shape of each pulse of the pulse trains transmitted by all LORAN-C master and secondary stations; FIG. 3 is a graphical representation of the pulse trains transmitted by the master and secondary stations within a LORAN-C chain. FIG. 4 is a representation of a portion of a LORAN-C navigation chart; FIGS. 5, 6, and 7 are detailed block diagrams of the Applicant's navigation receiver; FIG. 8 is a detailed block diagram of the smart shift register shown in FIG. 5; and, FIG. 9 shows the manner in which FIGS. 4, 5, and 6 should be arranged with respect to each other when reading the detailed description. GENERAL DESCRIPTION To understand the general or detailed operation of my novel LORAN-C receiver, it is best to first understand the makeup of the signals transmitted by LORAN-C stations and being received by my novel receiver. Representation of these signals are shown in FIGS. 2 and 3 which will now be discussed. All master and secondary stations transmit groups of pulses as briefly mentioned above, at a specified group repetition interval which is defined as shown in FIG. 3. Each pulse has a 100 Khz. carrier and is of a carefully selected shape shown in FIG. 2. For each LORAN-C chain a group repetition interval (GRI) is selected of sufficient length so that it contains time for transmission of the pulse chains from the master station and each associated secondary station, plus time between the transmission of each pulse train from the master station so that the signals received from two or more stations within the chain will never overlap each other when received anywhere in the LORAN-C chain coverage area. Each station transmits one pulse chain of eight or nine pulses per GRI as shown in FIG. 3. The master station pulse chain consists of eight pulses, each shaped like the pulse shown in FIG. 2, with each of the eight pulses spaced exactly 1,000 microseconds apart, and with a ninth pulse spaced exactly 2,000 microseconds after the eighth pulse. The pulse chain for each of the secondary stations X, Y and Z contains eight pulses shaped as shown in FIG. 2, and each of the eight pulses is also spaced exactly 1,000 microseconds apart. The pictorial representation of the pulses transmitted by the master station and the three secondary stations X, Y and Z associated therewith shown in FIG. 3 shows that the pulse trains never overlap each other and all are received within the group repetition interval. FIG. 3 also shows a representative time difference of arrival of the pulse train from each of the secondary stations with respect to the master station. These time difference of arrival figures are designated Tx, Ty and Tz and are the time differences measured using my receiver. It is to be recognized that the time difference of arrival between reception of the pulse train from the master station and the pulse trains from each of the X, Y and Z secondary stations will vary depending upon the location of the LORAN-C receiving equipment with the coverage area of a LORAN-C chain. In addition, the signal strength of the received signals from the master and secondary stations will also vary depending upon the location of the receiving equipment, as represented by the different heights of the representative pulse lines shown in FIG. 3. The delayed or spaced ninth pulse of each master station not only identifies the pulse train as being from a master station, but the ninth pulse is also turned on and off by the Coast Guard in a "blink" code, well known in the art, to indicate particular faulty secondary stations in a LORAN-C chain. These "blink" codes are published by the Coast Guard on the LORAN-C charts. In World War II when the LORAN-C systems were installed, carrier phase coding was used as a military security method, but after the war when the need for military security ceased, the phase coding was called a skywave unscrambling aid. In skywave unscrambling the 100 Khz. carrier pulses from the master station and the secondary stations in a LORAN-C chain are changed in phase to correct for skywave interference in a manner well known in the art. Skywaves are echoes of the transmitted pulses which are reflected back to earth from the ionosphere. Such skywaves may arrive at the LORAN-C receiver anywhere between 35 microseconds to 1,000 microseconds after the ground wave for the same pulse is received. In the 35 microsecond case, the skywave will overlap its own groundwave while in the 1,000 microsecond case the skywave will overlap the groundwave of the succeeding pulse. In either case the received skywave signal has distortion in the form of fading and pulse shape changes, both of which can cause positional errors. In addition, a skywave may be received at higher levels than a ground wave. To prevent the long delay skywaves from affecting time difference measurements, the phase of the 100 Khz. carrier is changed for selected pulses of a pulse train in accordance with a predetermined pattern. These phase code patterns are published by the Coast Guard on the LORAN-C charts. The exact pulse envelope shape of each of the pulses transmitted by all master and secondary stations is also very carefully selected to aid in measuring the exact time difference in arrival between a pulse train from a master station and a pulse train from a secondary station as is known to those skilled in the art. To make exact time difference measurement, one method the prior art teaches is superpositions matching pulse envelopes of pulses from a master station and a selected secondary station. Another method which I also utilize, is detection of a specific zero-crossing of the 100 Khz. carrier of the master and secondary station pulses. Now that the reader has an understanding of the nature of the signals transmitted by the LORAN-C master and secondary stations and how they are used for navigation purposes, the reader can better understand the operation of my novel LORAN-C receiver which will now be described. In FIG. 1 is seen a general block diagram of my novel LORAN-C navigation equipment. Filter and preamplifier 1 and antenna 2 are of a conventional design of the type used in all LORAN-C receivers and is permanently tuned to a center frequency of 100 Khz., which is the operating frequency of all LORAN-C transmitting stations. Filter 1 has a bandpass of 20 Kilohertz. Received signals are applied to smart shift register 3 and zero crossing detector 6. The signal input to zero crossing detector 6 is first amplitude limited so that each cycle of each pulse is represented by a binary one and each negative half cycle is represented by a binary zero. The leading or positive edge of each binary one exactly corresponds to the positive slope of each sine wave comprising each pulse. Thus, detector 6 is a positive zero-crossing detector. As will be described in detail further in this specification logic circuit 16 also provides an input to zero crossing detector 6, not shown in FIG. 1, which sets a 10 microsecond window only within which the leading edge of each binary 1 may be detected. The end result is that only the positive zero-crossing of the third cycle of each pulse of the train pulse trains transmitted by each LORAN-C station is detected and an output provided by detector 6. It can be seen that latch 5 has inputs from zero crossing detector 6 and logic circuit 4. Clock/counter 7 is a crystal controlled clock which is running continuously while my novel LORAN-C receiver is in operation. The count present in counter 7 at the moment that zero crossing detector 6 indicates a third cycle positive zero crossing is stored in latch 5, the contents of which are then applied to multiplexer 8. Multiplexer 8 is a time division multiplexer used to multiplex the many leads from logic circuit 16, latch 5, clock/counter 7, thumbwheel switches 11, 61 and 62 through to microprocessor 9. The count in latch 5 indicates to microprocessor 9 the time at which each positive zero crossing is detected. Smart shift register 3 has a filter at its input causing it to receive the output from receiver 1 within a narrower bandpass of five kilohertz centered on the carrier frequency of 100 Khz. The signal input to register 3 is also amplitude limited so that a pulse train of 1's and 0's is produced that is input to a shift register therein which is shifted at a 100 Khz. rate. Because of the 100 Khz. shifting frequency only the pulse trains from LORAN-C master and secondary stations will result in outputs from each of the individual stages of the shift register internal to smart shift register 3. Logic circuitry within register 3 is used to analyze the contents of the shift register internal to register 3 to first determine if the signals represent a pulse train from a LORAN-C station, secondly to determine if the pulse train is from a master or a secondary station, and finally to indicate the particular phase coding of the signals being received from a LORAN-C station. Logic circuit 4 includes a latch and a circuit to store information from register 3 indicating whether a pulse train is from a master or a secondary station and further indicating the phase code transmitted. This information stored within the latch of logic circuit 4 is applied to microprocessor 9 via multiplexer 8 for use in processing received LORAN-C signals. At the same time the information is stored on the latch within logic circuit 4 there is an output from circuit 4 enabling latch 5 to store the count in clock/counter 7 which will indicate the time of occurrence. It should be noted that clock/counter 7 also has an input to multiplexer 8 so that microprocessor 9 can keep track of a continuous running time as indicated by recycles of counter 7. The output of thumbwheel switches 11 are also input to multiplexer 8 allowing the operator of my novel LORAN-C equipment to input the group repetition rate of a selected LORAN-C chain to microprocessor 9. The group repetition rate is also called the Group Repetition Interval (GRI). In alternative embodiments of my invention thumbwheel switches 11 may be replaced by a keyboard which can be used by the operator to access microprocessor 9 to do many things including perform navigation calculations. With the various types of information being input to microprocessor 9 via multiplexer 8 from the circuits previously described, microprocessor 9 determines if and when signals being received via filter 1 are from the master and secondary stations of the selected LORAN-C chain. Once the microprocessor 9 locates the signals from the selected master station, as determined by a match of the GRI number input thereto via the four thumbwheel switches 11 with the difference in time arrival between each pulse train transmitted by the selected master station, microprocesor 9 similarly locates the corresponding secondary station signals. To locate the secondary stations microprocessor 9 creates a histogram from time of arrival information of any and all secondary station signals which are stored in twenty bins or slots created by the microprocessor in its own memory between the arrival of any two consecutive master station pulse trains. When signals from the secondary stations of the selected LORAN-C chain are located by secondary station signal counts appearing in the histogram bins at the same rate as the GRI of the selected LORAN-C chain, the microprocessor 9 performs a finer search by creating histogram bins of a shorter time duration. Each of the histrogram bins in which are stored the time of arrival counts of the signals of the appropriate secondary stations is then subdivided by microprocessor 9 into one hundred smaller time slot histogram bins to more closely determine the time of arrival of the pulse trains from the secondary stations of the selected LORAN-C chain. Each of these smaller histogram bins or slots stores counts corresponding to the time of receipt of signals received in consecutive twelve microsecond periods. In this manner, microprocessor 9 closely determines the time of arrival of pulse trains from the master and secondary stations of the selected LORAN-C chain within twelve microsecond periods. Once microprocessor 9 determines the particular twelve microsecond histogram time slots in which the secondary station signals are being received, the microprocessor causes an enable timing signal which causes the equipment to go into a fine search mode utilizing logic circuit 16 to accurately find the third cycle positive zero crossing of each pulse of the selected master and secondary station pulse trains. To accomplish this function, the approximate time of arrival of sequentially received pulses of the master and secondary station pulse trains are sequentially entered into latch 15 and the contents thereof are applied to comparator 14. Comparator 14 compares the contents of latch 15 with the contents of clock/counter 7 and upon there being a match, comparator 14 provides an output signal to logic circuit 16. The time entered into latch 15 is actually a time calculated to be 35 microseconds before the time of arrival of each pulse of the pulse train from a selected secondary station. The output from comparator 14 to logic circuit 16 is used to store three timing signals therein which are received from microprocessor 9. These three timing signals represent lines which occur 2.5 microseconds, 12.5 microseconds, and 30.0 microseconds after the output signal from comparator 14. At the end of each of these three timed sequences, the phase coding of a received pulse is checked against phase coding permanently stored in microprocessor 9. With the phase coding information, microprocessor 9 is able to accurately locate the third cycle zero crossing of each pulse of the pulse trains from the master and secondary stations. In the event that the previously described signal characteristics immediately prior to and at fixed points during a pulse are not received, microprocessor 9 knows that there is an error in its calculated time placed in latch 15 and microprocessor 9 either increases or decreases the calculated time of subsequent pulse trains by 10 microseconds and the new calculated time figure is placed in latch 15. Logic circuit 16 again analyzes incoming signals at the aforementioned points. This process of adding or subtracting 10 microseconds to the calculated time is repeated until microprocessor 9 accurately locates the third positive zero crossing of each pulse of the pulse trains transmitted by each of the master and secondary stations of the selected LORAN-C chain; then determines if the received pulse trains are from a master or a secondary station, and further determines the particular skywave phase code being transmitted by each of the stations. Once microprocessor 9 functioning with the other circuits in my LORAN-C receiver has located and locked onto the pulse trains being transmitted by the master and secondary stations of the selected LORAN-C chain and has made the desired time difference of arrival measurement that is required in LORAN-C operation, microprocessor 9 causes a visual indication to be given to the equipment operator via display 12. The output information is plotted on a LORAN-C hydrographic chart in a well known manner to locate the physical position of the LORAN-C receiver. DETAILED DESCRIPTION Turning now to describe in detail the operation of my novel LORAN-C equipment. In FIG. 2 is seen the shape or waveform of every pulse transmitted by both master and secondary LORAN-C stations. The waveform of this pulse is very carefully chosen to aid in the detection of the third carrier cycle zero crossing in a manner well known in the art. One method known in the art is to take the first derivative of the curve represented by the envelope of the pulse shown in FIG. 2, and this first derivative clearly indicates a point at 25 microseconds from the beginning of the pulse. The next zero crossing following this indication is the desired zero crossing of the third cycle of the carrier frequency. Similar to the prior art method just described, my novel LORAN-C receiver detects the third zero crossing for each pulse of the master station and each secondary station. The precise time difference of arrival measurements to be made utilizing a LORAN-C receiver are made by measuring from the third cycle zero crossing of the fifth pulse of the master station pulse train and the third carrier cycle zero crossing of the fifth pulse of the manually selected secondary station. In FIG. 3 is shown a representation of the nine pulse and eight pulse signals transmitted by a master station and the secondary stations of a LORAN-C chain. The small vertical lines each represent a pulse waveform such as shown in FIG. 2. The height of the vertical lines represents the relative signal strength of the pulses as received at a LORAN-C receiver. It can be seen that the signal strength of the pulses from the master station and each of the secondary stations are not identical. It can be seen in FIG. 3 that the group repetition interval (GRI) is defined as the period between the first pulses of two consecutive master station pulse trains for a given LORAN-C chain. This information is found on standard LORAN-C hydrographic charts and is used to calibrate the oscillator in my novel LORAN-C receiver as will be described to greater detail further in this specification. In a manner well known in the art, LORAN-C receiving equipment is used to measure the time difference of arrival between the pulse train from a master station pulse train and the pulse trains from two or more secondary stations associated with the master station. This time difference of arrival information is shown on FIG. 3 as T x , T y , and T z . In FIG. 4 is shown a representative figure of a LORAN-C hydrographic chart. On this chart are shown three sets of arcuate curves, each set of curves having a five digit number thereon and suffixed by one of the letters, x, y or z. The numbers directly correspond to the time difference of arrival information T x , T y and T z shown in FIG. 3 and measured by a LORAN-C receiver. In FIG. 3 the particular secondary station with which a set of the arcuate curves is associated is indicated by the suffix x, y, or z after the numbers on the curves. LORAN-C charts show land masses such as island 80 on FIG. 4. For an example, the operator of my LORAN-C receiver located on boat 81 near island 80 would measure the time difference of arrival information between the master station and at least two of the three secondary stations in the LORAN-C chain. The operator, in making a measurement with respect to the X secondary station would measure 379000 on my LORAN-C receiver. As can be seen in FIG. 4, the line of position (LOP) 379000 is shown passing through boat 81. In a similar manner, the operator would measure the time difference arrival information with respect to the Y secondary station and would come up with the number 699800 on the receiver. Again, the LOP for this receiver reading passes through boat 81. If the operator of the LORAN-C receiver measures the time difference of arrival information with respect to the Z secondary station the reading would show 493500 and the LOP for this reading also passes through boat 81. Thus, the operator can accurately fix the position of boat 81 on the LORAN-C chart. From this position information on the map of FIG. 4, boat 81 may, for example, be accurately navigated toward harbor 82 of island 80. It will be noted that the sample LORAN-C chart shown in FIG. 4 has only five digits on each LOP, but my LORAN-C receiver, has six digits. The lowest order or sixth digit is used to interpolate between two LOPs on the LORAN-C chart in a manner well known in the art. In the simple example given above, boat 81 is located exactly on three LOPs so no interpolation need be done to locate a LOP between those shown on the chart of FIG. 4. Thus, it should be noted that the six digit numbers obtained utilizing my equipment each included an extra zero suffixed to the end of the five digit LOP numbers shown on the LORAN-C chart. A sixth digit other than zero on the receiver would require interpolation between the LOP lines on the chart. In FIGS. 5, 6, and 7 is shown a detailed block diagram schematic of my novel LORAN-C receiver which I will now describe in detail. FIGS. 5, 6, and 7 should be arranged as shown in FIG. 9 to best understand the description found hereinafter. LORAN-C signals are received by a conventionally designed antenna 2 and conventionally designed filter and preamplifier 1, in a manner well known in the art. Interference caused by miscellaneous radio frequency signals and signals from other navigational systems are essentially eliminated by filter 1 which utilizes filters having a 20 Khz, bandwidth centered on 100 Khz, with a sharp drop off at either side of this band. Filter 1, being of a conventional design utilized in many LORAN-C receivers, is not described in further detail herein. Similarly, the choice of antenna 2 and/or the design thereof is also well known in the art and is not disclosed herein in detail for the purpose of not cluttering up the specification with details that are well known in the art and would detract from an understanding of the invention. The output from filter 1 is undemodulated and is applied to limiter 17 in zero crossing detector 6 and to 5 Khz, bandwidth filter 19. When my novel LORAN-C equipment is initially placed in operation, it is in a coarse search mode wherein it is only trying to generally locate the pulse trains from the master and secondary stations of the selected chain. This function is accomplished by smart shift register 3 as now described. Filter 19 has a five Khz. bandwidth centered on the 100 Khz. carrier frequency of the LORAN-C signals and causes rejection of most spurious signals. LORAN-C signals and a few spurious signals are passed through filter 10 to limiter 20. Limiter 20 demodulates and hard limits the signals input thereto so that only a chain of binary 1's is output from the limiter. Each of the binary 1's output from limiter 20 corresponds to a spurious signal pulse or to each of the pulses in the pulse trains from master and secondary stations. These pulses are applied to smart shift register 3 which is shown in block diagram form in FIG. 5, but is shown in detail in FIG. 8 and will be described in detail further in this specification. Smart shift register 3 is made up of ten serially connected shift registers, all of which are clocked or shifted at the same period as the pulses from master and secondary LORAN-C stations are received and logic gates. This is a one-thousand microsecond period as shown in FIG. 3. These ten shift registers store a window time sample of received signals which are analyzed to determine if the signal stored in the shift registers represents a pulse train from a LORAN-C master or secondary station. Due to the clocking the sample moves in time. The logic gates connected to various stages of shift registers provide outputs that are used to analyze the signals temporarily stored in the register to determine if received signals are from a master or secondary station and to determine if the received signals have what the U.S. Coast Guard refers to as group repetition interval A or B phase coding. These phase codes are well known to those skilled in the art. Upon smart shift register 3 determining that a pulse train has been received from a master or secondary station the internal logic gates, which are described in greater detail further in the specification, apply an output signal on one of leads MA, MB, SA, or SB, indicating if the signals are from a master or secondary station and the particular phase coding thereof. A signal indication that the received signals are from either a master or a secondary station is stored in latch 21. In addition, the last named signal output from register 3 is applied via OR gate 22 to the SET input of R/S flip-flop 23 to place this flip-flop in its set state with its 1 output high indicating that a pulse train from either a master or secondary station has been received. The 1 output of R/S flip-flop 23 is applied via OR gate 24 to latch 5. More particularly, this output signal from flip-flop 23 is applied to the clock input CK of latch 5 and causes the latch to store the contents of BCD counter 26 in clock/counter 7 at the moment in time that it is determined that signals have been received from the master or secondary station as indicated by the signal at input CK. The sored count is indicative of the real time at which the pulse train was received. As previously briefly described, the contents stored in latch 5 are applied to multiplexer 8 in FIG. 6 to thereafter be input to microprocessor 9. Multiplexer 8 in FIG. 6 is required to input signals to microprocessor 9 in FIG. 7 due to the limited number of input terminals to microprocessor 9 and the large number of leads over which signals must be applied to the microprocessor. Multiplexer 8 accomplishes this task utilizing time division multiplexing techniques. Integrated circuit multiplexers are available on the market, but may also be made up of a plurality of two input logic AND gates, one input of each of which is connected to the leads on which are the signals to be multiplexed, and the other input of each of which is connected to a clock and counter arrangement which causes ones or groups of the logic gates to have their other inputs sequentially energized in a cyclic manner. In this embodiment of my invention multiplexer 8 comprises Texas Instrument TI74151 multiplexers. It can be seen in FIG. 6 that there are inputs to multiplexer 8 from logic circuit 4, latch 5, clock/counter 7, thumbwheel switches 11, 61 and 62, logic circuit 16 and microprocessor 9. The signals input to multiplexer 8 from microprocessor 9 on leads 40 are used to control the operation of multiplexer 8. The contents of BCD counter 26 which are stored in latch 5 in response to the receipt of a pulse train from a master or secondary station are applied via multiplexer 8 to microprocessor 9 and indicate to the microprocessor the time of receipt of a valid pulse train from a master or secondary station. Following microprocessor 9 receiving the contents of latch 5 via multiplexer 8, indicating the time of receipt of a pulse train from a master or a secondary station, the microprocessor outputs a signal on LATCH RESET which is applied to reset latch 21 and clear the information stored therein in preparation of storing a subsequent master or secondary station indication. In addition, the CATCH RESET is applied via OR gate 60 to place flip-flop 23 in its reset state. As signals being input to microprocessor 9 from latch 5 will represent the receipt of master and secondary station signals from more than one LORAN-C station chain, microprocessor 9 requires an input from the equipment operator using thumbwheel switches 11 to indicate a particular LORAN-C chain of interest. The operator first consults a LORAN-C hydrographic chart published by the U.S. Coast Guard and finds the group repetition interval (GRI) for the LORAN-C station chain of interest. Using the four switches 11 the operator enters the repetition rate or GRI. As previously described, latch 5 is used to store the count present in BCD counter 25 each time a pulse train from a master or secondary station is detected by smart shift register 3. At the same time, the information stored in latch 21 is also applied to microprocessor 9 via multiplexer 8 to indicate the signal is from a master or secondary station and the phase coding thereof. In the previously mentioned initial coarse search mode microprocessor 9 analyzes master and secondary station information being input thereto via latch 5 to determine which indications represent signals from the stations of the selected LORAN-C chain. Microprocessor 9 stores the time of signal reception of the pulse trains from all master and secondary stations as indicated by the counts stored in latch 5 until it has definitely located and locked onto the selected stations and can therefore calculate the time of arrival of subsequent pulse chains therefrom. The microprocessor is programmed to create twenty bins or slots each corresponding to one of twenty sequential time periods of approximately twelve hundred microseconds duration each. The count stored in latch 5 when logic circuit 4 indicates a pulse train has been received from a master or secondary station causes a count to be stored internal to microprocessor 9 in the corresponding one of the twenty slots or bins. The microprocessor 9 is programmed to store the counts stored in these twenty bins, which make up a histogram to determine which bins contain counts indicating receipt of master and secondary station pulse trains at the correct GRI. Once microprocessor 9 is consistently receiving signals from the master station of the selected LORAN-C chain, it causes a front panel light designated "M" to be lit indicating that the receiver has locked onto the correct master station signals. As microprocessor 9 locates each secondary station associated with the selected LORAN-C chain, it causes a corresponding front panel light "51", "52", "53" and "54" to be lit as each secondary station is locked onto. This indicates to the operator which secondary stations are acceptable to use to make LORAN-C measurements. Microprocessor 9 then takes only the ones of the twenty histogram bins in which the selected chain master and secondary station signal counts are stored and subdivides each of these bins into one-hundred bins corresponding to sequential time slots of twelve microseconds duration each. The process just described is repeated for the shorter duration histogram bins created in memory internal to microprocessor 9 to more closely determine the time of arrival or receipt of the pulse trains from the secondary stations of the selected LORAN-C chain. When the above histogram processing has been accomplished to determine the time of receipt of master and secondary station pulse trains within twelve microseconds accuracy, microprocessor 9 generates an enable timing signal which causes the equipment to switch from the coarse search mode to a fine search mode to accurately make the LORAN-C time difference measurements as is described further in this specification. To place the equipment in the fine search mode, microprocessor 9 outputs a signal on its output COARSE DISABLE. The last named signal is applied via OR gate 60 to the reset input R of flip-flop 23 which prevents signals from register 3 being applied to the set input S and placing flip-flop 23 in its set or one state. Microprocessor 9 also applies a signal to its FINE ENABLE output causing the equipment to go into the fine search mode wherein the time of arrival of subsequently received signals is accurately made and a readout is provided on display 12. More particularly, the FINE ENABLE signal is applied to comparator 14 in FIG. 7 to enable same. One of the two inputs to comparator 14 is the output from BCD counter 25 in clock 7 on lead REAL TIME. The other input to comparator 14 is a number stored in latch 15 and this number is calculated by microprocessor 9 as is now described. Once microprocessor 9 determines the time of arrival of the signal trains from the master and secondary stations of the selected chain in the coarse search mode, and then switches to the fine search mode, it calculates the time of arrival of the subsequent pulse trains of the master and secondary stations from the secondary or fine (12 microsecond) histogram. Using the fine histogram, microprocessor 9 actually calculates a time 35 microseconds prior to the expected time of arrival of a subsequent master or secondary pulse train and loads this information into latch 15 over lead PRE-TIME under the control of another microprocessor generated signal on the CONTROL input. Comparator 14 compares the signal from clock 7 with the number stored in latch 15 and upon there being a match between these two digital numbers, there is an output from comparator 14 which places flip-flop 30 in logic circuit 16 into its set or one state. The one output of the flip-flop 30 is connected to the reset input R of counter 31 and to one of the two inputs of OR gate 32. Being in its one state the output of flip-flop 30 is high and this is applied via OR gate 32 to the set input S of flip-flop 33 which is thereby placed in its set state with its one output high. The high one output of flip-flop 30 being supplied to reset input R of counter 31 causes this counter to reset to zero. Once reset to zero, counter 31 counts to a count of 8, stops counting and causes its TC output to go high. The TC output of counter 31 is applied to the reset input R of counter 34 which is disabled from counting once counter 31 reaches a count of eight and is thereby disabled from counting. This occurs because flip-flop 30 being placed in its set state with its one output high enables counter 31 to count by resetting it to zero whereby its TC output goes to zero, thereby removing the signal to the reset input R of counter 34. Counter 34, which is reset to zero count, is thereby enabled to count in response to the 1 MHz signal being input to its clock input CK. Counter 34 is different than counter 31 in that it counts up to its maximum count of 10,000 and then resets itself to zero to recount to 10,000 again and again. Because of counter 34 counting and recounting to 10,000, its output TC has a signal thereat which occurs at a 1,000 microsecond rate due to the dividing action by counter 34 of the 1 MHz signal at its CK input. Thus, counter 34 is providing output signals at the same rate that each of the pulses are being received in the pulse trains from the master and secondary stations. The TC output of counter 34 is applied to the second input of OR gate 32 and is also applied to the clocking input CK of counter 31. This causes the count in counter 31 to be increment by one each time counter 34 counts to 10,000. Thus, at the end of 8,000 microseconds counter 31 will have reached its full count and its output TC is high which, being applied to the reset input R of counter 34, causes counter 34 to be reset to zero and to cease counting. Counter 31 will not be reset to zero until flip-flop 30 is returned to its reset state with its one output low. This happens when output TC goes high, which being connected to reset input R of flip-flop 30, causes it to be reset to its zero state. This removes the high input to reset input R of counter 31, leaving the counter at its full count with its output TC high. One of the purposes for the timing function accomplished by counters 31 and 34 is to check the phase coding of the pulse trains being received from the selected master and secondary stations. Upon microprocessor 9 changing over the receiver to the fine search mode, the microprocessor parallel loads the phase coding for the first eight pulses of the master and secondary station pulse trains of the selected LORAN-C chain into parallel/serial converter 35 of logic circuit 16. Converter 35 is a conventional shift register well-known in the art which may be loaded in parallel and then shifted out in serial to perform parallel to serial conversion. As is well known in the art, each of the pulses of the pulse trains received from master station and secondary stations has a particular phase coding. This phase coding is stored in microprocessor 9 and is selected by information input to the equipment by the operator using thumbwheel switches 11. It can be seen that the clocking input CK to converter 35 is the same 1,000 microsecond signal output from counter 34. Thus, the contents of converter 35 are serially shifted out at its output Q at a 1,000 microsecond rate. It should be noted that the output Q of converter 35 is connected to one of the two inputs of exclusive OR gate 36 in zero crossing detector 6. Exclusive OR gate 36 functions as an inverter in this case in a manner known to circuit designers. When a particular one of the pulses of the pulse trains received from a master or secondary station is of a positive phase there is no signal or a zero on output Q from converter 35 if the phase codes match. The result is that each radio frequency cycle of the particular pulse which is hard limited by limiter 17 will pass directly through exclusive OR gate 36 to flip-flop 37 unchanged. Upon the expected receipt of each particular pulse of the pulse trains from the master and secondary stations which are to be of a negative phase, converter 35 will have shifted its contents such its output Q will be high or a one. This high input applied to the second input of exclusive OR gate 36 causes OR gate 36 to invert the phase of the pulse output from limiter 17. That is, the signal being input to detector 6 is effectively shifted 180° thereby eliminating the negative phase coding applied to the particular pulse. This is done in order that there will be an output from exclusive OR gate 36 to place flip-flop 37 in its set state at exactly the beginning of each pulse of the pulse trains from the master and secondary stations. Fiip-flop 37 in detector 6 being placed in its set state with its one output high as described heretofore, causes latch 5 to store the contents of counter 26 at that particular moment in time. Microprocessor 9 thereby receives a time indication of the beginning of each radio frequency cycle of each of the pulses and this information is used to make the required time difference of arrival measurements which are the basis or the LORAN-C system. Flip-flop 37 is returned to its reset state before the beginning of the first cycle of a subsequent pulse received from a master or secondary station by the LATCH RESET signal as described heretofore. Microprocessor 9 determines the estimated time of arrival of the third cycle positive zero crossing of each of the pulses of the next to be received pulse train from the selected master and secondary stations. Microprocessor 9 then subtracts 35 microseconds from this time which results in a time that should occur five microseconds before the beginning of the first radio frequency cycle of each pulse of the master and secondary station pulse trains. This point in time occurring 5 microseconds before the beginning of each pulse of the pulse trains is output from microprocessor 9 on its output leads PRE-TIME and is input to latch 15 under control of signals from the microprocessor on the input CONTROL. The contents of latch 15 are applied to comparator 14 which is enabled by the microprocessor energizing input E upon the equipment being placed in the fine search mode. It should be noted that comparator 14 also has an input thereto designated REAL TIME, which is the lock output from BCD counter 26 of clock/counter 7 in FIG. 5. Upon there being a match of the two inputs to the comparator 14, there is an output therefrom which places flip-flop 30 in logic circuit 16 into its set state and its one output goes high. As mentioned heretofore, this enables counters 31 and 34 to commence counting as previously described. The one output of flip-flop 30 is also coupled by an OR gate 32 to the set input S of flip-flop 33 to place this flip-flop in its set state with its one output high. As seen in FIG. 6, the one output of flip-flop 33 is connected to the reset inputs of counters 38, 39 and 41, and to the clocking input CK of flip-flop 42, all in logic circuit 16. The purpose of these last listed circuit elements is to help microprocessor 9 analyze each received pulse of the pulse trains from the master and secondary stations to accurately determine the time of arrival of the third cycle positive zero crossing of each pulse. It can be seen that the clocking input CK to each of counters, 38, 39 and 41 is driven by a clock signal on lead CLK. The source of this clocking signal is the 10 megahertz clock 45 in clock/counter 7 in FIG. 5. Flip-flop 33 being placed in its one state energizes the reset input R of each of counters 38, 39 and 41, thereby resetting these counters to zero and enabling these counters to commence counting. As can be seen in FIG. 6, counter 38 is designated a 30 microsecond counter. This means it counts and provides a signal at its output TC 30 microseconds after this counter is enabled to count. Similarly, counter 39 has an output signal on output TC 2.5 microseconds after this counter is enabled to count. Also, counter 41 has an output signal at output TC 12.5 microseconds after this counter is enabled to count. Thus, 2.5 microseconds after comparator 14 caused flip-flop 30 to be placed in its set state, which thereby causes flip-flop 33 to be placed in its set state, there is an output from counter 39 to the clocking input CK of flip-flop 43 of logic circuit 16. The output TC of counter 39 remains high until its reset input R is deenergized. Similarly, 12.5 microseconds after counter 41 is enabled by resetting there is an output therefrom to the clocking input CK of flip-flop 44. Flip-flop 43 is a D type flip-flop which will store whatever signal is present at its D input upon its clocking input CK being energized. It should be noted that the D input of flip-flop 43, as well as the D input of flip-flops 42 and 44 is obtained from the output of exclusive OR gate 36 in zero-crossing detector 6 in FIG. 5. The output of OR gate 36 is a square wave pulse corresponding to each radio frequency cycle of each pulse of the pulse trains received from the master and secondary LORAN-C stations and also inverted to account for phase coding as previously described. Counter 39 will time out and cause the clocking input CK of flip-flop 43 to go high at a point in time 32.5 microseconds before the expected arrival of the third cycle positive zero crossing of each pulse. It should be noted that this 32.5 microsecond point occurs 2.5 microseconds before the first cycle of each pulse. At that point in time only noise should be received by the LORAN-C equipment and, more particularly, only noise of a frequency that falls within the 10 kilohertz bandwidth of filter 1. Statistically noise pulses applied to the D input of flip-flop 43 will occur as often as they do not occur. Thus, counter 39 energizing clocking input CK of flip-flop 43 will cause this flip-flop to store either zero's or one's on a proportionally equal basis if the microprocessor 9 has accurately determined the third cycle positive zero crossing and the output signal from counter 39 does occur prior to the beginning of each pulse. The Q output of flip-flop 43, as well as the Q outputs of flip-flops 42 and 44, are coupled via multiplexer 8 to microprocessor 9 as can be seen in FIGS. 6 and 7. Microprocessor 9 receives and stores the output of flip-flop 43 for a total of 2,000 samples and is programmed to average these samples received from flip-flop 43. There will be approximately an equal number of zero's and one's received therefrom if the input to the D input of flip-flop 43 is received prior to any pulse of the pulse trains from the master and secondary stations. Counter 41 completes its count 12.5 microseconds after it is enabled by the output signal from comparator 14 as previously described. The output from counter 41 occurs 7.5 microseconds after the beginning of the first cycle of each pulse of the pulse trains if microprocessor 9 has accurately determined the position of the third cycle positive zero crossing of each pulse. This point in time will occur during the mid-point of the negative cycle of the first radio frequency cycle of each pulse. Thus, the moment counter 41 energizes clocking input CK of flip-flop 44, the D input of this flip-flop from exclusive OR gate 36 will be a zero. The result is that the Q output of flip-flop 44 will also be a zero which will be forwarded to microprocessor 9 via multiplexer 8 as previously described. Microprocessor 9 also stores each output from flip-flop 44 for 10,000 samples, one per pulse, and is programmed to average these samples to determine if they are predominantly zero representing a negative half cycle. In the event microprocessor 9 does not initially accurately determine the location of the third cycle positive zero crossing of each pulse of the pulse trains from the master and secondary stations, and this will usually happen upon microprocessor 9 initially switching the LORAN-C equipment into its fine search mode, the outputs from flip-flops 43 and 44 will not be as described immediately hereinabove. When the estimated time is too long, the sample points clocked into flip-flops 43 and 44 by counters 39 and 41 respectively will both occur during each pulse of the pulse trains. As a result, the averages made by microprocessor 9 for flip-flops 43 and 44 will yield positive or negative averages and will not yield a zero average. In response to this condition, microprocessor 9 subtracts 10 microseconds from the estimated time of arrival and the sequence described above is repeated. When the estimated time is too short the averages of the stored samples at the 2.5 microsecond and 12.5 microsecond points will both be zero and microprocessor 9 will add ten microseconds to the estimated time of arrival. This recalculation and repeat of the circuit operation just described is repeated until the output from flip-flop 43 yields a zero average to microprocessor 9 and the output from flip-flop 44 yields a negative average. As microprocessor 9 gets closer to the exact time of arrival, the microprocessor can add or subtract less than 10 microseconds to the calculated time to determine the exact estimated time of arrival figure. Counter 38, which is also enabled to count upon receipt of the output signal from comparator 14 via flip-flop 33, counts to time a period of 30 microseconds at the end of which it provides an output at its output TC. Output TC from counter 38 is connected to the reset input R of flip-flop 37 in zero-crossing detector 6 and to the reset input R of flip-flop 33. Flip-flop 37 is thereby placed in its reset state with its one output low immediately prior to the receipt of the third cycle positive zero crossing of each received pulse of the pulse trains from the master and secondary stations of the selected LORAN-C chain. The hard limited output from limiter 17 occurring immediately after flip-flop 37 is placed in its reset state is responsive to the third cycle positive zero crossing of each pulse. As a result, the one output of flip-flop 37 goes high in direct correspondence with the leading edge of the hard limited square wave pulse output from limiter 17 and corresponding to the third cycle position zero crossing. As previously described, this causes the count contents of BCD counter 25 to be clocked into latch 5 and indicates the exact time of receipt of the third cycle positive zero crossing of each pulse of the pulse trains. This information is applied via multiplexer 8 to microprocessor 9 as previously described for processing. In response to this information, microprocessor 9 can make the desired time difference of arrival measurements required in LORAN-C equipment. Upon the time difference of arrival measurements being made, microprocessor 9 provides appropriate outputs on its DISPLAY outputs leads which are input to display 12. The signals output from microprocessor 9 to display 12 are applied to the appropriate digital display units therein. Digital display unit 51 is used to visually display the time difference of arrival information for one selected secondary station, and digital display 52 is used to visually display the time difference of arrival information for a second selected secondary station. The inputs to these digital displays is encoded and is appropriately decoded by anode drivers 46 and 47, anode driver 48 and decoder/drivers 40 and 50 to drive digital displays 51 and 52 respectively. These displays along with their associated decoding and driving circuitry are well known in the art and are commercially available. In this embodiment of my invention, displays 51 and 52 are Itron FG612A1 flourescent displays, but they may also be light emitting diode displays or liquid crystal displays, or any other form of visual display. To select the secondary stations, the time difference of arrival measurements for which are to be displayed on displays 51 and 52, thumbwheel switches 61 and 62 are provided. Switch 61 is physically adjacent to display 51 and one of the numbers "1" to "4" are selected with this switch to indicate to processor 9 the information to be displayed. Similarly, thumbwheel switch 62 is associated with display 52 and is used by the equipment operator to indicate the particular secondary station arrival measurement to be displayed on display 52. Switch 11 shows no details but is made up of right individual switch such as represented by switch 61 in FIG. 7. The operation of a detented thumbwheel brings numbers into a window and output terminals of the switch indicates the chosen number. A signal to noise button 62 is also located on the front panel of the equipment which while depressed by the operator causes the existing display on displays 51 and 52 to be replaced by a signal to noise figure for the same secondary stations indicated by the position of the corresponding ones of switches 61 and 62. Microprocessor 9 is programmed to calculate the signal to noise figures to be displayed and responds to the operation of button 62 to change the display on displays 51 and 52. To make this signal to noise ratio check, microprocessor 9 stores fourteen-thousand samples of the first negative half cycle of each pulse as indicated by counter 41 described in detail hereinabove. As is easily understood, pure noise would yield seven-thousand detected negative half cycles and seven thousand positive half cycles, and a perfect signal would yield fourteen thousand detected negative half cycles. Accordingly, numbers between seven thousand and fourteen thousand indicate the signal to noise ratio with this ratio getting higher as the count of detected negative half cycles increases toward the sample number of fourteen thousand. It is numbers between seven thousand and fourteen thousand that will be displayed on displays 51 and 52 when signal/noise button 62 on the front panel is operated. It can readily be seen that microprocessor 9 can be programmed to display numbers from 0 to 100 corresponding to the range of seven thousand to fourteen thousand by using a simple interpolation algorithm. Any other number scheme may also be used to indicate signal to noise. While that which has been described hereinabove is at present considered to be the preferred embodiment of the invention, it is illustrative only, and the rapid changes in technology will make various changes and modifications obvious to those skilled in the art without departing from the scope of the invention as claimed below. Thus, for example, programming may be added to the microprocessor and the keyboard may be used or input and the display as output to perform calculations of all kinds, or the display may, in addition, be used to provide a digital clock with day, date and other information. In another variation the microprocessor may provide navigation instructions via the display.

LORAN-C navigation apparatus is disclosed wherein digital circuitry and a microprocessor is used to automatically identify LORAN transmitting stations and makes standard hyberbolic navigation measurements. The equipment operator manually enters the group repetition rate into the apparatus for a LORAN-C chain covering the area within which the navigation apparatus is being operated. Initially, the apparatus searches all incoming signals until signals from a master station are received regularly at the stored group repetition rate. The apparatus then closely determines the time of arrival of signals from the secondary stations of the selected LORAN-C chain before changing to a fine search mode in which the exact time of arrival of the secondary station signals is determined; the phase code of the received signals is checked to determine if the received signal is a ground or sky wave, and a determination is made if there is a defective secondary station blink code. The time difference of arrival measurements are then output visually to be plotted in a well known manner on a LORAN-C chart to locate the position of the craft upon which the apparatus is located.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in part application of international application PCT/EP2008/008250 having a filing date of 28 Sep. 2008, the disclosure of which is incorporated herein by reference in its entirety, and claims the benefit under 35 USC 119 of German patent applications 10 2007 046 136.6 filed 27 Sep. 2007 and 10 2007 046 135.8 filed 27 Sep. 2007, the contents of which are incorporated herein by reference in their entirety. BACKGROUND OF THE INVENTION The invention relates to a mixing faucet for two liquids of different temperatures that comprises a mixing valve, a perforated plate valve with an actuation quantity that determines the volume of an outflow, and at least one rotary actuator mounted in a rotary degree of freedom in relation to a fixed housing, wherein rotation of the at least one rotary actuator adjusts at least a first of two independent coaxial rotational control variables to control the volume or temperature of an outflow. Mixing faucets with two rotary actuators are known, which adjust two incoming flows by means of one closing valve or one closing and mixing valve for each of the said flows, whose rotational axes include an angle between 60° and 120° or are spaced at a distance to one another. The disadvantage of these mixing faucets is that the quantity and temperature of the outflow can only be adjusted in combination by two gripping movements, whereby the two movements enable fine adjustability. This is achieved by single uniaxial rotary movements rotating through angles of up to more than 360°; this is known by experience as the best actuating movement because it is known to be most safely and confidently controllable. Mixing faucets are also known with one actuator movable in two degrees of freedom. DE1198150A and DE2724429A1 describe mixing faucets with an actuator that sets the quantity of outflow by a shift in the direction of the rotational axis and the size ratio of two inflows via a rotational movement of max. 150°. The disadvantage is the limited angle of rotation of 150°, which does not assure fine adjustability. The longitudinal movement is ergonomically even more unfavorable and gives only unsatisfactory results. DE2636517A1 discloses an actuator with two degrees of freedom. A shift in the direction of the rotational axis switches to adjust either the quantitiy of the outflow or the size ratio of two inflows by rotating the single actuator by max. 180°. The to disclosed design requires two movements for a change of temperature, that is: firstly, the longitudinal movement to switch, then the rotational movement; this is not only cumbersome but also ergonomically implausible and thus unfavorable. Moreover, additional pulling or pushing force is applied during the rotational movement for one of the adjustments in order to maintain the adjusted setting, which makes handling more difficult. Thus, despite the single directly accessible actuator, only one variable is available in direct access. Fine and accurate adjustment is thus not possible due to the limited angle of rotation. The complex valve design with one closing and mixing valve for each inflow is delicate and costly, and the mixing valve is difficult to clean and replace. The entire valve construction is obsolete. Lever mixer faucets are the most familiar type (for example DE3411447A1, DE2324364A), having a lever handle as the rotary tilting actuator with two degrees of freedom, in which the initial longitudinal movement of a piston valve that is also rotatable is converted into a vertical tilting movement of the lever to adjust the outflow quantity. It is now state of the art to equip these lever mixing faucets with a ceramic perforated plate mixing valve, whereby the movable perforated plate is in direct rotational contact with the lever actuator. The temperature is adjusted by means of a rotational movement of the lever actuator via the size ratio of two inlet cross sections, and the outflow quantity is adjusted via the size of the inlet cross sections by means of a rotation-dependent tilting movement of the same lever actuator. In these lever mixing faucets, only tilting angles of less than 30° and angles of rotation of less than 120° are feasible, which is ergonomically inadequate. The combination of two basically single rotational or tilting movements in the same actuator results in an unmanageable and barely controllable three-dimensional movement, which is not capable of intuitive regulation when operated only briefly. The adjustment movement has to be corrected subsequently and as experience shows, it has to be broken down into the two basic movements, although a successful, clear separation of the two is rare. It has become apparent that, for over 90% of people, the two basically independent variables, outflow quantity and temperature, are almost impossible to adjust accurately by means of a combined rotational and tilting movement. Inadvertent maladjustment, such as opening the faucet unintentionally, happens easily merely by knocking against the lever handle, which may even lead to scalding in the worst case. It is known from DE10347819A1 to provide a mixing faucet without a mixing valve, the mixing faucet having two coaxial rotary actuators in succession. The required high torque can only be applied with levers, even if an intermediate gear is present. Each rotary actuator operates a closing valve for cold or hot water respectively. This does not permit a deliberate clear setting of the temperature or outflow quantity, as the temperature results from the relative angle of rotation of both rotary actuators. Nor are the directions of access either the same or consistent, so that genuine single handed operation (i.e. access with one hand) is ruled out. The angles of adjustment are extremely small due to reduction by the internal crown gear, and this is only slightly and inadequately compensated by the intermediate gear. At the same time, this system increases the differentials in the direction of access. Fine and accurate adjustment is impossible with this principle. Thermostatic mixers (e.g. DE3118003A1, DE10044684A1, EP0242680A2) have two single-axis rotary actuators, which are widely spaced in an ergonomically unfavorable manner, with access from opposite directions, even though they permit 180° of rotation for the quantity and 360° for the temperature of the outflow. This necessitates two grasping movements and opposite rotational movements, thus ruling out comfortable single-handed operation. Thermostatic mixers that are partially built into the wall (DE10048041A1) are provided with two coaxial rotary actuators arranged in succession, with a rotational angle of approximately 360° (for the temperature) and just under 90° (for outflow volume control), and can be adjusted from two directions of access lying at least close together. The front rotationally symmetrical rotary actuator for the temperature can be grasped and positioned at the end, the rear rotary actuator for the outflow volume works due to the high torque only via a radial lever, and this does not allow genuine single-handed operation. Both adjustment movements are achievable only by means of dual access, in which the direction of access to the lever changes during the adjustment movement in absolute and, above all, relative terms in relation to the direction of access of the front rotary actuator. Temperature adjustment is more obvious and easier than the adjustment of the outflow volume. This is ergonomically inadequate, as the volume adjustment at the start of the outflow has the highest priority when operating a mixing faucet. Moreover, the built-in thermostat is requires complex installation in the wall, hence is not suitable for the common and by far the most frequent use in visible applications as sink, shower and bath faucets. An object of the invention is to create a mixing faucet that will allow selective, substantially direct, comfortable, and clear setting of the two target variables, i.e. temperature and quantity of outflow, substantially independently of each other whilst ruling out inadvertent actuation, for example by a mere knock, thus creating the conditions for genuine single-handed operation in a permanent direction of access, also of thermostatic mixers, using proven valve technology at little extra cost. SUMMARY OF THE INVENTION This problem is solved by the invention by means of a torque converter that is able to convert the type of movement, position and/or magnitude of the actuator quantity into the first rotational control variable on a plane that is in particular parallel to the sliding plane of the perforated plate valve. This torque converter is so efficient that it enables independent clear and sure setting of both rotational control variables smoothly and without lever reinforcement across the full range of adjustment, using only two fingertips on approximately opposite sides of the envelope surface of the rotary actuator in substantially only one position of the accessing hand. In this embodiment of the mixing faucet, the simple and low-cost torque converter transforms, by means of conversion of movement, such as a displacement and/or deflection, a degree of freedom defined by the valve technology of the perforated plate valve controller into an ergonomically favorable adjustment movement for operation, and thus enables use of the said embodiment in various proven valve technologies such as perforated ceramic plate valves, thermostatically controlled valves—the design of which may need to be optimised if appropriate. The torque converter not only opens up in principle a simple means of obtaining transmission ratios far in excess of 2, but also creates the conditions for setting the two target variables, temperature and outflow volume, independently of one another, deliberately and accurately in an ergonomically optimum position and manner of movement, with the optimum input of movement energy in the form of adjustment range and adjustment force. The pre-requisite for this is that the two adjustment movements are not coupled in any way. The concept of the invention with one or more torque converters allows designs in which the ergonomically most simple and precise uniaxial rotary operating movement is realised for both rotational control variables independently of each other by applying two fingertips on approximately opposite sides of the outer envelope surface of the rotary actuator in an ergonomically favorable position. The rotary actuator is unlevered and substantially invariate in relation to its adjustment movements. Each rotary actuator has only one degree of freedom in relation to the stationary housing. Inadvertent operation is thus ruled out in principle. Invariance allows access independently of the current angular position of the rotary actuator. This means that access requires no particular positioning of the hand. This is comfortable operation, as it is not necessary to recognize the current angular position of the rotary actuator or to adjust the positioning of the hand accordingly when accessing it, and is thus the precondition for the simple interchange between two rotary actuators. Invariance can be achieved by rotational symmetry to the axis of rotation. In the simplest case, this is a smooth cylinder with the rotational axis as the axis of symmetry. Slight variations from rotational symmetry are advantageous for a secure grip between fingertips and outer envelope surface, for example polygonal shapes such as a round-cornered triangle or square, etc. The said variations from symmetry should, however, be limited in such a way that no special position or holding of the hand is required when accessing it, in order to avoid any impairment of the comfort of operation. Alternatively, the outer envelope surface of the rotary actuators can be axially gnurled for a secure friction or form fit, or it may be provided with longitudinal ribs with a thickness of about 1 to 2 mm and a height of up to 3 mm, or grooves of 1 to 2 to mm in depth. They can be arranged such that the rotational symmetry of the actuators, hence their invariance in relation to rotation about their axis of rotation is substantially not or only negligibly limited for handling. Furthermore, the invention enables two rotary actuators to be arranged in a design with the same direction of access such that the said rotary actuators can be operated selectively by moving only the fingers from just one position, after positioning the hand for access, this with extreme smoothness and ease. This forms the basis for clear and targeted true single-handed operation using only two fingertips, which is substantially different from known “single handed mixing faucets”. Furthermore, the more important adjustment—outflow volume—can be arranged to be reached more easily in the direction of access, and hence to take preference, this being ergonomically correct, so that the sum of all these advantages amounts to the highest ease of operation. The use of a simple, flat torque converter, for instance made of injection molded plastic, keeps down the extra cost. The cost with a perforated plate mixing valve is comparable to that of lever type mixing faucets, the standard medium-range mixing faucets or, in the case of a thermostatic valve, with those of built in thermostats. The invention enables a very compact, stable construction with both housing rotary actuator embodiments in thin stainless steel pipes, and cast brass or plastic. The inventive combination of torque converters with leverless single-handed finger-operated rotary actuators opens up the way for a great diversity of artistically harmonious design alternatives. In a further embodiment of the invention, the actuating movement, of the fingertips of the accessing hand can operate to switch to either of the control variables with no movement of the arm and no substantial displacement of the hand, resulting in the highest comfort of single-handed operation even when setting both rotational control variables in one action. This is of particular interest in equipping bathrooms for the elderly or sanitary facilities for people with handicaps. The torque converter enables practically any limitable torque adjustment by converting an actuation quantity into the corresponding rotational control variable with a transmission ratio of 1.6 to over 4, thus determining and assuring the smoothness of a rotational control variable. At the same time, almost any size of positioning angle can be achieved up to well over 250°. The result is the greatest ergonomic comfort of operation combined with sensitive and accurate adjustment. The gearing effect of the torque converter can also be achieved or reinforced with an additional gear. Shaping the torque converter in the general form of a circular disc and arranged in parallel spacing to the slip plane of the perforated plate valve, results in the most compact structure of a perfectly cylindrical shape, as the central axis of the torque converter can be selected to be identical to all the axes of rotation of the rotary actuators and rotational control variables. The design is simplified if the axes of rotation of the rotational control variables and the associated actuators intersect each other or all, or in the simplest case, are identical. Further simplification results from arranging the axes of rotation of the rotational control variables normal to the slip plane of the perforated plates and hence to the plane in which the actuator quantities lie. This applies both when a rotary actuation quantity of the movable perforated plate is transformed (e.g. by a planetary gear) into a rotational control variable, and in the conversion of a translatory actuation quantity into a rotational control variable. If the rotational control variables are uniaxial rotations whose axes of rotation are identical, in particular to the axis of rotation of the rotary actuator(s), the conditions are given for the simplest formal structure, i.e. in the basic form of a cylinder that is invariate with regard to the adjustment movements and has its direction of access to the end in the same direction as the axis of rotation. For ergonomic reasons, but also by reason of artistic and design considerations, it may be advantageous if the axes of rotation of the rotary actuators include an angle of more than 0° and approximately in the range of 30°. It makes the engineering easier if they intersect. The smallest adjustment effort, i.e. the most convenient and ergonomically sound solution, is achieved when, selectively and independently of the current relative position of the rotary actuator, only two or three fingertips at a time need to be placed from the same direction of access on one or two rotationally symmetrical outside envelope surfaces, which are then rotatable by the fingertips without any movement of hand or arm. The switchover then also takes place without hand or arm movement by a small displacement of the fingertips, either from outer envelope surface to outer envelope surface or with the outer envelope surface. From the ergonomic point of view, the outflow volume adjustment should have higher access priority, that is, it should be reached automatically or “blind”. This means that the rotational control variable for adjusting the outflow volume from the direction of access is adjustable more directly, hence more simply and easily. This is achieved by constructing the required torque for setting the outflow volume lower or at least not substantially higher than that of the rotational control variable to set the temperature, by ensuring that a switchable rotary actuator is coupled as a default pre-setting with the rotational control variable to adjust the outflow volume or, if there are two rotary actuators, that the one for adjusting the outflow volume is accessed first. In an embodiment as a single mixing faucet, the metering and mixing function is realized with a double perforated plate valve as a mixing valve, whereby its two actuation quantities are each adjustable with one rotational control variable virtually independently of the other. The temperature of the outflow is manually adjustable via a rotational control variable as a ratio of the two flows with different temperatures entering the mixing valve through the inlet holes. In an embodiment of the invention as a single-handed thermostat, a two perforated plate valve is a closing valve having a common angle of rotation of 65 to 90° as the actuation quantity for the outflow. The outflow temperature is controlled according to the rotational temperature control variable as a set value for the temperature by a thermostatic element in a thermostat valve as the mixing valve. Prior art thermostatic mixer are constructed with coaxial rotary actuators with to the same direction of access, having an internal housing and a housing, whereby the rotary actuator for the temperature set point is mounted inside the internal housing. The said housing transmits the rotational control variable for flow quantity from the annular rotary actuator arranged behind the end-facing rotary actuator for the temperature to the perforated plate valve. This neither meets the ergonomic priority of volume adjustment, nor does it offer independent control movements. Ergonomically correct handling can be achieved when the internal housing and the housing partially interpenetrate each other. The housing is divided in into an outermost and innermost part, in which the axis of rotation of the rotational temperature control variable is mounted in a fixed position. The internal housing is arranged between these parts and provided with openings, through which the struts on the innermost part, which are open to the outermost part, reach until they are in supporting contact, centering the housing. The width of the struts, the size of the openings and the number of both on the circumference are co-ordinated such that the internal housing is rotatable against the two-part housing by the maximum angle of rotation of the perforated plate valve. In an embodiment of the mixing faucet of the invention with a second uniaxial rotary actuator for the second rotational control variable, direct access is created to each rotational control variable. In this way, the two rotational control variables can be set directly and clearly, each with an easily controllable single-axis rotation and without any additional effort that would impede the action or detract from its plausibility. For single-handed operation, the axis of rotation of the second rotary actuator should run closely, preferably parallel to the axis of rotation of the first rotary actuator. The closer the rotary actuators are arranged to a direction of access, the more convenient the single-handed operation will be. If their axes of rotation are identical, the two rotary actuators can be operated in only one action of one hand. If they are arranged directly behind one another, the fingertips will be moved only slightly by about 2 cms substantially in the direction of its axis of rotation, to switch to the desired rotary actuator and thus to switch the rotational movement of the fingers to one of the two rotational control variables. When access to the handle is from the end in the direction of the axis of rotation, the result is the ergonomically optimised structure. The rotary actuators form a substantially invariate rotational body to the adjustment movements. The rotational actuation can be made more explicit and the adjustment force input reduced with a radial lever, although this is superfluous in the invention. It complicates the adjustment movement, especially with large but precise control angles, and does not allow true single handed operation with two rotary actuators. The direction of access changes with the current relative position, requiring recognition of the current relative position to enable co-ordination of the access movement with it before accessing the actuator and performing the adjustment action. A switching gear in the form of a torque converter as embodied in the invention enables switching the rotation of the fingers on a rotary actuator to either of the two rotational control variables, for example via an interchangeable coupling. A rotary actuator with an additional degree of freedom for switching between the two rotational control variables has, by nature, a uniform direction of access and also an identical axis of rotation for both control movements. Said rotary actuator is directly accessible by the shortest route. The rotational control variables can be set unambiguously with a uniaxial rotation. However, only the first control variable is directly accessible and is a simple rotation if for instance a spring pre-sets and holds the rotary actuator in switching position for the first rotational control variable. The setting of the second rotational control variable requires a switchover before the rotation movement and a holding force during the rotation movement, the said holding force being superimposed on the adjusting force. The simplest case for a switchover is a thrust movement in the direction of the axis of rotation—either by pushing or pulling. The thrust movement can either be orthogonal to the direction of the axis of rotation or a pivoting or tilting movement of the rotary actuator or a part of the mixing faucet. Interchangeable couplings include friction or toothed radial, axial or bevel couplings. The advantage of friction couplings is the short working distance and the smooth coupling action in every relative rotational position of the rotational control variables. The advantage of toothed coupling is the lower holding force, which does not have to be the higher normal force that generates the adhesion/friction force, but only has to overcome the switch spring and assure torque transmission after the coupling action. When applying the concept of the invention to a single-handed thermostat, the angle of rotation of about 90° of the movable perforated plate can be transmitted by a planetary gear, which can be arranged entirely inside the rotary actuator, in the entrance via the land or ring gear to the rotational control variable at the sun gear. The said sun gear is connectable torsion-resistantly to the rotary actuator with an identical axis of rotation. The actuation quantity has a high torque, due to seals and seal grease, and at the same time a smaller angle of rotation. The said high torque can be converted with a more than threefold transmission ratio into an ergonomically convenient adjustment movement. A simple, reliable valve for the two functions of mixing and metering is the double ceramic perforated plate mixing valve, of which at least the first actuation quantity is a displacement of a first movable perforated plate of the perforated plate valve having in particular one hole, in relation to a second perforated plate arranged with a surface in surface contact with said first perforated plate, the second perforated plate being fixed in the housing and having two inlet bores and in particular one outlet bore. A second actuation quantity can be, in particular, a degree of freedom of a third perforated plate of the perforated plate valve arranged movably in relation to the first perforated plate with its contact surface in surface contact and/or second perforated plate preferably as a mixing valve It is simpler to utilize two degrees of freedom of the first perforated plate independent of one another in relation to the second perforated plate for the two actuation quantities of the perforated plate valve especially as the mixing valve. To this end, a rotation or a second displacement orthoganol to the first displacement can be used as the second degree of freedom, whereby the outflow volume is not changed by adjusting the temperature, and vice versa. The target variables temperature and outflow volume can thus be set clearly and independently of each other. There is surface contact by means in particular of grease between the movable first perforated plate with one hole and the second perforated plate fixed in the housing and having two inlet holes and one outlet hole in its contact area. In principle, the control element and the movable perforated plate may be identical. It is recommendable for reasons of engineering design, however, to transfer the actuation quantities to the perforated plate via a control element in direct supporting contact with the movable perforated plate. Alternatively, the second actuation quantity can be selected as a degree of freedom of a third movable perforated plate. A second actuation quantity of a valve controller can be converted into the second rotational control variable either by an additional degree of freedom of the first torque converter or by a separate second torque converter. With a rotatory degree of freedom, the said second actuation quantity can be utilised directly as a rotational control variable. Both are then identical and can be the rotation of the second rotary actuator at the same time. A very elegant solution for a suitable flat torque converter is a cam plate gear made up of a ring-shaped spirally grooved cam disc and a slider. The motion link of the said slider is guided in the helical groove. It is advantageous to arrange the center of the helix on the axis of rotation of the helical groove disc. The slider carries a tappet that engages in a groove of the controller, the length of which corresponds to its width and the displacement of the other degree of freedom. The perforation enables the passage of the dog of a second slider and/or the rotatable mounting of the cam disc on a shaft with an outside diameter corresponding to the diameter of the hole. Here, too, kinematic inversion is possible, of course, wherein the guide to groove is replaced by a guide rib on the cam disc and the motion link is replaced by a slider. The simplest, most symmetrical and most compact design is given when the axes of rotation of at least one rotational control variable and at least the associated cam disc are identical or when even also the axis of rotation of the rotary actuator is identical. Then the rotary actuator and the cam disc can be rotatably mounted on a shared shaft, preferably the neck of a cartridge, both being connected to one another in particular torsion-resistantly, and executed preferably in one piece. If the axes of rotation of the two rotational control variables, the two cam discs and the two rotary actuators are identical, they can all be mounted on a single fixed shaft without frictional contact between the two rotational control variables. A cartridge connects the valve and the torque converter to form a module. It reduces noise emission via the atmosphere and gives all the valve and gear members guidance and support. In this way, a slider can be mounted slidably in a groove of the cartridge and a cam disc with a perforation or port can be rotatably mounted on a shaft of the cartridge or with a shaft or its outer edge in a bore of the cartridge or also on the inner side of the circular cartridge envelope. The cartridge also serves to facilitate assembly when the valve or the torque converter is replaced. With a second gear, especially a flat torque converter, the second actuation quantity of the perforated plate valve as the mixing valve or of a second valve, is convertible to the second rotational control variable. When using two, especially flat torque converters for the two degrees of freedom of the movable perforated plate, it is advantageous to arrange the torque converter gears in surface contact above each other, on condition that one torque converter has a fixed aperture such as, for example, a perforation concentric with the axis of rotation of the cam disc in a cam disc gear, to carry the transmission from the other gear through it. In the case of cam disc gears with grooved discs, the grooved disc and slider can each be layered above each other alternately like blocks. They guide and support each other reciprocally. This results in the most compact, stable and, if the axes of rotation of the cam discs are identical, the simplest structural principle, wherein large parts of the torque converter can be accommodated inside the rotary actuator. If at least one, and especially all of the rotary actuators preferably having a direction of access from the front, is/are invariate in its/their external form to its/their respective degree of freedom, they can be grasped with the fingers and adjusted in any position without prior orientation. With two successively arranged rotary actuators with the same axis of rotation, the switch from one to the other is possible in any relative rotatory position without any correction of position of the fingers, making handling genuinely most convenient. The invention also allows for the rotary actuator(s) to be electrically driven. The angle of rotation can be set by a manual adjuster, more particularly operated by at least one finger, preferably by means of an incremental rotary position transducer. The mixing faucet of the invention enables mixing in the quasi widened pipe, i.e. in a purely rotationally symmetrical external shape, wherein the outflow can be carried through the torque converter(s) and preferably the rotary actuator(s), particularly through the passage, which is preferably formed by a centrally perforated cam disc. To this end, the mixing valve, perforated plate valve, rotary actuator and in particular the torque converter can define a cavity open at opposite ends, preferably and partially formed by a cartridge, which positions the mixing valve, perforated plate valve, rotary actuator and torque converter especially in relation to each other. The cavity preferably extends in particular along the central axis of the housing from the inlet holes to the outlet of the outflow, and/or the mixing valve, perforated plate valve, rotary actuator and in particular the torque converter are formed as concentric rings. A channel for the outflow, connecting the mixing valve and the outlet, can lead through at least part of the cavity, said channel being formed at least in part more particularly by a central pipe leading out of the housing. If the rotary actuator(s) and in particular the housing are formed in a rotationally symmetrical manner, with its/their central axi(e)s preferably in alignment with the central axis of the central pipe, a generally uniform rotationally symmetrical outer shape can be created as the simplest embodiment. The simplest embodiment of a mixing valve as a robust ceramic threefold perforated plate valve can be achieved by means of a third perforated plate in surface contact with the movable first perforated plate, both of them being formed with in particular one hole each, of which one is larger than the other about the control paths and both of them opening into each other and into the channel connecting the mixing valve and the outlet for the outflow Further features and advantages of the invention will be apparent from the claims and the following description of the drawings, in which three embodiments of the invention are visualised diagrammatically. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows in a perspective drawing a mixing faucet according to the invention, in which for the sake of simplicity the usual outflow arm and the inlet connections are not shown. FIG. 2 shows another perspective diagram of the same embodiment, in which, for the sake of easier visibility, only the valve and the torque converter are exploded vertically and shown spaced from one another by 5 mm each, leaving out the rotary actuator, the cartridge and the housing. FIG. 3 shows another perspective illustration of the same embodiment, in which one rotary actuator with the associated cam disc is vertically exploded by 20 mm in each case in relation to the adjacent part, leaving out the housing. FIG. 4 a perspective view of a second embodiment of a mixing faucet according to the invention, in which the usual outflow arm and the inlet connections are not shown. FIG. 5 shows a diagrammatic cross-section of the actuating mechanism of the simplified second embodiment of a mixing faucet according to the invention, in which thermostat valve is shown with thermostatic element only as a black box, openings to and struts that penetrate them are represented by the bold dotted lines, and the outflow arm and connections are omitted. FIG. 6 a and FIG. 6 b show two sections orthagonally placed to each other in a third embodiment of the mixing faucet of the invention, in which the contact cross sections of holes are projected as a phantom. DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1 the mixing faucet is shown in the usual external view. The two cylindrical rotary actuators 31 , 32 , which are invariate in relation to their adjusting movements, and each having a uniaxial rotatory degree of freedom 311 , 321 , are arranged, directly above one another. The access direction 6 is the same and constant across the entire range of adjustment. The external envelope surfaces are gnurled in order to guarantee a secure friction engagement even with soapy fingers. Their axes of rotation are identical with the center axis of the housing 170 , which is also cylindrical. This upright arrangement corresponds to the use of the mixing faucet in sinks or wash basins. The hand comes from the end and above parallel to the axes of rotation to grasp it. The ergonomically advantageous length of the housing 170 beneath the two rotary actuators 31 , 32 is between 45 and 200 mm. The preferable external diameter of the two rotary actuators 31 , 32 is between 25 and 50 mm. If the external diameter of the housing 170 corresponds to those of the rotary actuators 31 , 32 , they will be between 40 and 50 mm. Their height is preferably between 15 and 40 mm each, depending on the respective diameter, in order to enable reliable operation by a single hand in one action. When using the mixing faucet for showers or bathtubs, the mixing faucet is arranged rotated by 90° in horizontal position, so that the two rotary actuators 31 , 32 point forward towards the user. The housing length behind the rotary actuators 31 , 32 is then approximately 65 mm. The bottom part of FIG. 2 shows a perforated plate mixing valve 1 , consisting of a first perforated plate 11 , fixed in the housing (not shown), having one inlet hole 180 each for hot and cold water and an outlet hole 190 for the mixed water, and a to second performated disc 12 , arranged in surface contact in a contact area 140 with it, being displaceable in relation to the said first perforated plate in two orthogonally translatory degrees of freedom as actuation quantities 51 , 52 , the said second perforated plate 12 being connected to the control element 150 in positive locking manner. This arrangement has the purpose firstly to deflect the incoming cold and hot water flows by 180° and secondly, it carries two control grooves 121 , 122 . The main direction of extension corresponds in each case to one of the two actuation quantities 51 , 52 to receive the dogs 111 , 112 . Above the control element 150 are two cam disc gears as flat torque converters 41 , 42 , layered en bloc in surface contact with each other. Their members mutually support and guide each other. Each of them has a slider 101 , 102 arranged beneath an annular grooved disc as the cam disc 71 , 72 , each with one single-axis rotatory degree of freedom as the rotational control quantity 21 , 22 , which in this embodiment corresponds in each case to the degree of freedom 311 , 321 of the rotatory actuator 31 , 32 , with which they are connected torsion resistantly. The said slider 101 , 102 is guided with its motion link 81 , 82 in the helical guiding groove 91 , 92 on the underside of the grooved disc. The two cam disc gears convert the two displacements, which are orthogonal to one another and defined by the valve construction as actuation quantities 51 , 52 of the perforated plate 12 into single-axis rotations of the cam discs 71 , 72 with limited torque and a large actuating angle as the rotational control variables 21 , 22 . The axes of rotation of the two cam discs 71 , 72 are identical, centric to their external envelope surface and normal to the contact surface 140 of the two perforated plates 11 , 12 . The dog 111 of the upper torque converter projects through the passage 13 of the cam disc 72 of the lower torque converter 42 into the control groove 122 of the control unit 150 . The passage 13 is a circular centric hole concentric with the axis of rotation of the cam disc that allows sufficient play for the displacement of the actuation quantity 51 of the upper slider 101 and is in fixed position, as its central axis is identical with the axis of rotation of the lower cam disc 72 . FIG. 3 discloses the interconnection between the two rotary actuators 31 , 32 to with the same direction of axis 6 and the two torque converters 41 , 42 and shows the fixed cartridge 200 , which defines the relative positions of all the members of the torque converters 41 , 42 and the first perforated plate (not shown) of the perforated mixing valve 1 . The said mixing valve is defined in the housing (not shown) and has two inlet holes 180 in its base for the hot and cold inflows, and an outlet hole 190 for the mixed outflow. The bottom part is an almost closed cylinder enclosing the perforated plate mixing valve 1 and the control element 150 . The upper closure of this cylinder has a groove 212 to receive and guide the slider 102 of the lower torque converter 42 in the direction of its sliding movement as actuation quantity 52 . Further up, the cartridge 200 continues into a neck with a circular ring-shaped cross section, which is interrupted by another groove 211 to receive and guide the slider 101 of the upper torque converter 41 in the direction of its displacement as actuation quantity 51 . The neck forms a common shaft 220 , on which the two cam discs 71 , 72 , and hence the two associated torsion-resistantly connected rotary actuators 31 , 32 , are rotatably mounted in pairs in their degrees of freedom 311 , 312 . In this way, the axes of rotation of the two rotary actuators 31 , 32 and the two cam discs 71 , 72 , hence the rotational control variables 21 , 22 are identical. The degrees of freedom 311 , 312 of the rotary actuators 31 , 32 are also those of the cam discs 71 , 72 as rotational control variables 21 , 22 and identical in this embodiment. Because of the uniform rotational symmetry about the vertical center axis as the single, shared axis of rotation, the entire torque converter 41 and a large part of the torque converter 42 can be accommodated simply inside the rotary actuator 32 in a mutually guiding and stabilising manner. In the embodiment of FIGS. 4 and 5 , the mixing faucet is a true single-handed thermostatic mixer with thermostat valve 2 as the mixing valve to control the actuation quantity for the mixing ratio of the inflows, which determines the temperature of the outflow according to a set point specified by the rotational control variable 22 and perforated plate valve 1 , to control the actuation quantity 51 for the size of the outflow as a closing valve actuated by rotational control variable 21 . With a switching gear as the torque converter 41 , the two rotational control variables 21 , 22 can be actuated from a permanent direction of access 6 with one action of one hand by means of only one uniaxial rotary actuator 31 . An additional translatory degree of freedom 312 in the direction of the axis of rotation of its first rotational degree of freedom 311 allows the addition of a radial shift gear 17 , 18 . Depending on its final position 3121 , 3122 in its degree of freedom 312 during the rotation of its degree of freedom 311 , the said shift gear 17 , 18 either couples the said additional degree of freedom 312 with the movable perforated plate 12 of the perforated plate valve 1 via the hollow shaft 35 , planetary gear 29 and the internal housing 171 , or with the actuator of the thermostatic control element 45 of the thermostatic valve 2 , via the crown gear 16 , axis 152 , screw thread 65 and thrust sleeve 66 , as a result of which its rotatory degree of freedom 311 corresponds to one or the other rotational control variable 21 , 22 . Internal housing 171 and housing 170 interpenetrate each other by means of openings 64 and struts 63 passing through the said openings. To this end, the housing 170 is divided into an outermost, closed portion 62 and an innermost portion with openings 61 forming struts 63 for supporting contact, the said struts 63 being open to the outermost portion 62 . The two portions 61 , 62 , are torsion-resistantly and releasably connected. The axis 152 for the rotational control variable 22 and the thrust sleeve 66 are mounted in the innermost portion 61 . The internal housing 171 is arranged between these portions 61 , 62 and provided with openings 64 , through which the struts 63 of the innermost portion 61 of the housing 170 grasp outwards far enough to center and support the outermost portion 62 . The width of the struts 63 and the size of the openings 64 are co-ordinated such that the internal housing 171 can be twisted in relation to the two-part housing 170 by the maximum actuation quantity 51 as the angle of rotation of the movable perforated plate 12 of the perforated plate valve 1 of about 65 to 80°. Actuation quantity 51 is defined via the internal housing 171 for turning the planet gear carrier 25 . The ring gear 26 is fixed in the outermost part 62 of the housing. The resulting rotation of the sun gear 27 with limited torque and enlarged angle of rotation of preferably more than 250° forms the rotational control variable 21 . The transmission ratio is preferably 1.6 to 4, more particularly via 2. Interchangeable coupling 17 , 18 , and the planetary gear 29 together form the switching gear as the torque converter 41 . The interchangeable coupling 17 , 18 is held in its end position 3121 by means of a spring 19 as the pre-setting, so that the adjustment of the rotational control variable 21 is always possible in a direct, sure and practically “blind” manner without any additional coupling action. This conforms to the ergonomic priority for the adjustment of the outflow volume, which determines the start and finish of drawing water. To switch to end position 3121 and thus to rotational control variable 22 , the spring force must be overcome by a compression force in the direction of access 6 to maintain the setting for the entire duration of adjustment. This can be achieved by the upper end surface 310 of the rotary actuator 31 impacting the cupped hand as it grasps in the direction of access, the height of the rotary actuator being selected to be greater than the depth of the cupped hand, or by a secure friction bond between the adjusting fingertips and the outer envelope surface of the rotary actuator 31 , e.g. by circumferential gnurling The third embodiment of a mixing faucet of the invention according to FIG. 6 a and FIG. 6 b is also a genuine one-hand mixer. The two conical rotary actuators 31 , 32 are invariate in relation to their adjustment movements, each having a uniaxial rotary degree of freedom 311 , 321 . The said rotary actuators 31 , 32 are arranged directly on top of each other. Their direction of access 6 is the same, constant across the entire range of adjustment, and almost at the end of the rotary actuator 31 in a very small angle of the central axis of the whole rotary body. This is formed jointly by the housing 170 , rotary actuators 31 , 32 and the central pipe 230 opening into the outlet 231 (shown shortened) to a “widened pipe”. The central axis shared by all of them is also the axis of rotation of the two rotary actuators 31 , 32 , through which either of the rotational control variables 21 , 22 can be set from a hand position by finger movement only, by shifting the fingertips merely in the direction of the central axis from one rotary actuator 31 , 32 to the other. Each of the rotational control variables 21 , 22 leads to a rotation of a cam disc to 71 , 72 with the helical guide groove 91 , 92 , in which runs the motion link 81 , 82 of a slider 101 , 102 . The said slider 101 , 102 is in surface contact with the cam disc 71 , 72 and is guided in a straight linear groove 211 , 212 of the cartridge. This enables any rotational control variable 21 , 22 to be converted into one of two translatory actuation quantities 51 , 52 of the movable perforated plate 12 that are orthogonal to each other and hence independent of each other. The two flows coming in through the inlet holes 180 are mixed in the mixing valve 1 with three perforated plates and guided in the same direction out of the housing 170 to the outlet 231 via the central pipe 230 arranged in the cavity 232 defined by the perforated plate valve 1 , annular torque converters 41 , 42 and annular rotary actuators 31 , 32 , the said cavity being partly limited by a neck 220 of the cartridge 200 . The actuation quantity 52 causes a displacement of the hole 121 in relation to the two holes of the inlet bores 180 , thereby adjusting the ratio of the inflows, hence the temperature of the outflowing mixed flow. The actuation quantity 51 also causes a shift of hole 121 in relation to the two inlet holes 180 , although the two holes are more or less closed to the same degree. Thus, the volume of the mixed outflow is adjusted. Perforated plate 14 has a larger hole 141 than hole 121 , so that the displacements are balanced out again and the mixed flow always flows into the central pipe 230 . The cartridge 200 positions all parts in relation to one another and is closed on its underside with a bottom. It is supported by an intermediate floor of the housing 170 . This upright arrangement corresponds to the use of the mixing faucet on sinks or wash basins. It can also be used in a horizontally or obliquely in relation to the wall tap. Accordingly, other embodiments and modifications are conceivable and feasible within the scope of the claims. The object of the invention is not limited to the embodiments shown in the drawings and described above.

A compact and low-cost mixing faucet for liquids of different temperatures is proposed that allows fine and accurate adjustment of the volume and temperature of the mixed outflow by single-handed operation. The mixing faucet is suitable for use of a ceramic perforated plate and/or thermostatic mixing valve. The actuation quantities can be converted by torque converters to rotational control variables in an ergonomically optimum type, magnitude and/or positioning of movement, such that both rotational control variables can be selectively adjusted when manually operated by accessing from a permanent direction of access. The hand position enables actuation of the faucet with only two fingertips, with torque limitable up to any degree of smoothness and a large angle of rotation at the associated rotary actuator. The rotational control variable for the outflow volume can be made ergonomically easier to reach and adjust from the direction of access.

This application is the U.S. national phase of International Application No. PCT/IB2008/050321 filed 30 Jan. 2008, which designated the U.S. and claims priority to NZ Application No. 552936 filed 30 Jan. 2007, the entire contents of each of which are hereby incorporated by reference. FIELD OF THE INVENTION The invention relates to a method of producing moulded foam products from polylactic acid (“PLA”) polymer. The invention also relates to pre-expanded PLA beads, impregnated PLA beads and the products made from such. BACKGROUND OF THE INVENTION There are polymer foams used for insulation and packaging applications with good performance to price ratio. But because these forms are petroleum-derived, there is increasing environmental and consumer demand for using biofoams—biologically derived foams—for some applications. PLA is a ‘green plastic’ being bio-derived and bio-degradable. A useful blowing agent, carbon dioxide, is a ‘green’ blowing agent because it has no ozone depletion potential and a tiny global warming potential. A number of attempts have been made to develop a process for foaming PLA in order to provide a green alternative to materials such as polystyrene foam (expanded polystyrene/EPS). Because of a small processing window and the theological properties of the PLA polymer melt, many of these processes were unsuccessful or unsatisfactory. The processes that were to some extent successful often required complex processes and/or additives such as nucleating agents to improve the foaming and the fusing parts of the process. See for example United States patent publication US 2006-0167122 that reports that use of a nucleating agent is necessary. There are a number of reported processes that use carbon dioxide as a blowing agent including uses in relation to PLA. Reported PLA foaming and moulding processes using PLA resin beads impregnated with carbon dioxide generally involve impregnating the beads with gaseous or supercritical CO 2 , pre-expanding the impregnated beads, resting and sometimes treating the pre-expanded beads, before re-impregnating them with more CO 2 or another blowing agent and further expanding and fusing them in a mould. See for example European patent application EP 1 378 538 that reports use of blends comprising predominantly crystalline PLA that require re-impregnation with blowing agent before moulding. It is an object of the present invention to provide a simple method of foaming PLA resin beads or to at least provide the public with a useful choice. SUMMARY OF THE INVENTION Accordingly, a first aspect of the present invention relates to a method of forming a composition of expanded polylactic acid (PLA) resin beads, the method comprising impregnating PLA resin beads with CO 2 by contacting the beads with liquid CO 2 ; and holding the impregnated beads at a temperature and pressure that prevents the beads from foaming while allowing the level of impregnated CO 2 to reduce to about 5 to 18 weight % relative to the total weight of the beads and CO 2 . Preferably the method further comprises pre-expanding the beads at a pre-expansion temperature. Promptly following pre-expansion or after a desired storage period, the method may further comprise introducing the pre-expanded beads into a mould and further expanding and fusing the beads in the mould by application of a temperature greater than the temperature used for pre-expansion. A second aspect of the present invention relates to a method of manufacturing a moulded polylactic acid (PLA) product, the method comprising impregnating PLA resin beads with CO 2 by contacting the beads with liquid CO 2 ; holding the impregnated beads at a temperature and pressure that prevents the beads from foaming while allowing the level of impregnated CO 2 to reduce to about 5 to 18 weight % relative to the total weight of the beads and CO 2 ; pre-expanding the beads at a pre-expansion temperature; introducing the pre-expanded beads into a mould; and further expanding and fusing the beads in the mould by application of a temperature greater than the temperature used for pre-expansion. A third aspect of the present invention relates to a method of forming a composition of expanded polylactic acid (PLA) resin beads, the method comprising (1) providing a composition of impregnated PLA beads prepared by a process comprising (a) impregnating PLA resin beads with CO 2 by contacting the beads with liquid CO 2 ; (b) holding the impregnated beads at a temperature and pressure that prevents the beads from foaming while allowing the level of impregnated CO 2 to reduce to about 5 to 18 weight % relative to the total weight of the beads and CO 2 ; and (2) pre-expanding the beads at a pre-expansion temperature. As described above, the method may further comprise optionally storing the beads in a pre-expanded state. Alternatively, promptly following pre-expansion or after a desired storage period, the method may further comprise introducing the pre-expanded beads into a mould and further expanding and fusing the beads in the mould by application of a temperature greater than the temperature used for pre-expansion. A fourth aspect of the present invention relates to a method of manufacturing a moulded polylactic acid (PLA) product, the method comprising (1) providing a composition of impregnated PLA beads prepared by a process comprising (a) impregnating PLA resin beads with CO 2 by contacting the beads with liquid CO 2 ; and (b) holding the impregnated beads at a temperature and pressure that prevents the beads from foaming while allowing the level of impregnated CO 2 to reduce to about 5 to 18 weight % relative to the total weight of the beads and CO 2 ; (2) pre-expanding the beads at a pre-expansion temperature; (3) introducing the pre-expanded beads into a mould; and (4) further expanding and fusing the beads in the mould by application of a temperature greater than the temperature used for pre-expansion A fifth aspect of the present invention relates to a CO 2 impregnated PLA resin bead having a CO 2 wt % of about 5 to 18% manufactured by immersing a PLA resin bead in liquid CO 2 until equilibrium then storing the bead in refrigerated conditions until the CO 2 level drops to about 5 to 18%, about 5 to 12%, or about 8 to 12% by weight. Preferably the bead is stored until the CO 2 level drops to about 5 to 18%, more preferably about 5 to 12%, and most preferably about 8 to 12% by weight. A sixth aspect of the present invention relates to a pre-expanded CO 2 impregnated PLA resin bead manufactured by immersing an PLA resin bead in liquid CO 2 until equilibrium then storing the bead in refrigerated conditions until the CO 2 wt % level drops to the about 5 to 18% by weight then pre-expanding the bead under ambient pressure and a temperature of about 20-110° C. or about 50-110° C. A seventh aspect of the present invention relates to a moulded product made from fused expanded PLA resin beads manufactured by an aspect of the invention described above, such as immersing PLA resin bead in liquid CO 2 until equilibrium, storing the bead in refrigerated conditions until the CO 2 level drops to about 5% to 18% by weight, pre-expanding the bead at a pre-expansion temperature, immediately transferring the pre-expanded beads to a mould, and further expanding and fusing together the beads by application of a temperature greater than that used for pre-expansion. Preferred moulded products include moulded blocks and shaped moulded products, especially blocks adapted to form packing material. Other preferred moulded products include convenience items such as containers including clamshell containers, pots, boxes, bowls, cups, plates and trays. An eighth aspect of the present invention relates to a method of manufacturing a moulded polylactic acid (PLA) product, the method comprising impregnating PLA resin beads with CO 2 by contacting the beads with liquid CO 2 ; holding the impregnated beads at a temperature and pressure that prevents the beads from foaming while allowing the level of impregnated CO 2 to reduce to about 5 to 18 weight % relative to the total weight of the beads and CO 2 ; pre-expanding the beads at a pre-expansion temperature; introducing the pre-expanded beads into a mould; and further expanding and fusing the beads in the mould by application of a temperature lower than or equal to the temperature used for pre-expansion. Any of the following embodiments may relate to any of the aspects described above or below. In one embodiment impregnation is conducted by contacting the PLA resin beads with liquid CO 2 , preferably immersing the PLA resin beads in liquid CO 2 , until the absorption of CO 2 by the beads reaches equilibrium. The amount of CO 2 adsorbed by the beads at equilibrium will depend on the nature of the PLA beads and the impregnation pressure and temperature. The amount of CO 2 adsorbed by the beads at equilibrium may be determined experimentally by determining the maximum amount of CO 2 that a selected population of beads will adsorb at a desired pressure or temperature. In one embodiment impregnation is conducted until the percentage of CO 2 absorbed by the beads is at least about 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 or 35% by weight relative to the weight of the CO 2 and the beads, and useful ranges may be selected between any of these values (for example, about 18-35%). In some embodiments impregnation is conducted in a pressure vessel and the temperature and pressure in the pressure vessel during impregnation is selected so that the percentage of CO 2 absorbed by the beads is about 18-35% by weight relative to the weight of the CO 2 and the beads. Preferably, the temperature and pressure in the pressure vessel during impregnation is selected so that, in combination with the type and grade of PLA resin beads, the percentage of CO 2 absorbed in the beads is about 18-35% by weight. In one embodiment impregnation is conducted by contacting the PLA resin beads with liquid CO 2 at a pressure of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 MPa, and useful ranges may be selected between any of these values (for example, about 1 to 10, 2 to 10, 3 to 10, 4 to 10, 5 to 10, 6 to 10, 7 to 10, 8 to 10, 1 to 8, 2 to 8, 3 to 8, 4 to 8, 5 to 8, 6 to 8, or 7 to 8 MPa). In one embodiment impregnation is conducted by contacting the PLA resin beads with liquid CO 2 at a temperature of at least about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18° C., and useful ranges may be selected between any of these values (for example, about 2-18, 3-17, 4-16, 5-15, 6-14, 7-13, 8-12 or 9-11° C.). In one embodiment impregnation is conducted by contacting the PLA resin beads with liquid CO 2 , preferably by immersing the PLA resin beads in liquid CO 2 , at a pressure of about 5-8 MPa and a temperature of about 5-15° C. In another embodiment impregnation is conducted by contacting the PLA resin beads with liquid CO 2 at a pressure of about 5-8 MPa and a temperature of about 8-12° C. In another embodiment impregnation is conducted by contacting the PLA resin beads with liquid CO 2 at a pressure of about 5.5-6.5 MPa and a temperature of about 5-15° C. In another embodiment impregnation is conducted by contacting the PLA resin beads with liquid CO 2 at a pressure of about 5.5-6.5 MPa and a temperature of about 8-12° C. In one preferred embodiment the liquid CO 2 is not mixed with any dispersion medium during impregnation. In one embodiment impregnation is conducted for at least about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230 or 240 minutes, or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours, and useful ranges may be selected between any of these values (for example, about 10 to 240, 10 to 200, 10 to 150, 10 to 100, 20 to 240, 20 to 200, 20 to 150, or 20 to 100 minutes, or 1-24, 2-23, 3-22, 4-21, 5-20, 6-18, 7-17, 8-16, 9-15 or 10-14 hours). For example, in one embodiment, a low impregnation pressure (e.g. up to about 5 MPa) is used with a long impregnation time (e.g. at least about 4 hours) or a high impregnation pressure (e.g. at least about 5 MPa) is used with a short impregnation time (e.g. up to about 4 hours). In one embodiment, following impregnation of the beads the pressure is reduced to ambient pressure and the beads are held under refrigerated conditions. Preferred refrigerated conditions include holding by storage at about or at less than about 8, 6, 4, 2, 0, −2, −4, −6, −8, −10, −12, −14, −16, or −18° C. In one embodiment, following impregnation the PLA resin beads are held in refrigerated conditions until the CO 2 wt. % decreases to about 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, or 4%, preferably about 4-20%, 5-18%, 5-12%, or 8-12% by weight. In one embodiment the beads are held for at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90 or 96 hours, and useful ranges may be selected between any of these values (for example, about 1-24, 2-23, 3-22, 4-21, 5-20, 6-18, 7-17, 8-16, 9-15 or 10-14 hours). In one embodiment pre-expanding the beads comprises applying suitable temperatures to initiate the nucleation and growth of gas pores. In one embodiment pre-expanding the beads is conducted at ambient pressure. In another embodiment pre-expanding the beads is conducted at a pre-expansion temperature of about 19 to 110° C., about 19 to 71° C., or about 49 to 71° C. In one embodiment pre-expanding the beads is conducted by heating the beads to the pre-expansion temperature for at least about 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230 or 240 seconds, and useful ranges may be selected between any of these values (for example, about 5 to 240, 5 to 200, 5 to 150, 5 to 120, 5 to 100, 10 to 240, 10 to 200, 10 to 150, 10 to 120, 10 to 100, 20 to 240, 20 to 200, 20 to 150, 20 to 120, or 20 to 100 seconds). The further expanding (foaming) and fusion of the beads in a mould is conducted at a temperature (the moulding temperature) greater than that used in pre-expansion. In one embodiment the foaming and fusion of the beads in a mould is conducted by the application of steam. In another embodiment the foaming and fusion of the beads in a mould is conducted by the application of steam and vacuum. In one embodiment the beads are subjected to the moulding temperature for at least about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230 or 240 seconds, and useful ranges may be selected between any of these values (for example, about 10 to 240, 10 to 200, 10 to 150, 10 to 100, 20 to 240, 20 to 200, 20 to 150, or 20 to 100 seconds). In one embodiment the moulding temperature is at least about 40, 50, 60, 70, 80, 90, 100, 110 or 120° C., and useful ranges may be selected between any of these values (for example, about 40-120, 50-110, 60-100, or 70-90° C.). In one embodiment a vacuum is applied to the mould for at least about 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230 or 240 seconds, or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 minutes, and useful ranges may be selected between any of these values (for example, about 1 to 240, 1 to 200, 1 to 150, 1 to 100, 1 to 50, 1 to 10, 10 to 240, 10 to 200, 10 to 150, 10 to 100, 10 to 50, 20 to 240, 20 to 200, 20 to 150, or 20 to 100 seconds, or 1-15, 2-14, 3-13 or 4-12 minutes). In one embodiment, the further expanding and fusion of the beads in a mould is conducted at a temperature lower than or equal to that used in pre-expansion. In one embodiment the PLA resin beads comprise at least about 50, 60, 70, 80, 90, 95, 99 or 100% PLA by weight. In another embodiment the beads comprise amorphous PLA. In another embodiment the beads comprise at least about 50, 60, 70, 80, 90, 95, 99 or 100% amorphous PLA by weight. In another embodiment the beads comprise a blend of amorphous PLA and crystalline PLA, preferably about 50, 60, 70, 80, 90, 95 or 99% amorphous PLA and about 1, 5, 10, 20, 30, 40, or 50% crystalline PLA. In another embodiment, the beads comprise a blend of PLA and aliphatic polyester or ethylene-vinyl-acetate (EVA), preferably about 80, 85, 90, 95 or 99% PLA and about 1, 5, 10, 15, or 20% aliphatic polyester or EVA. Preferably the aliphatic polyester is Bionelle™ (Showa Denko K.K., Japan). In one embodiment the PLA resin beads comprise a filler. In one embodiment the fillers are inert and biodegradable. Suitable fillers include but are not limited to talc, calcium carbonate, calcium stearate, sand, clay, zeolite, bark (including pine bark), sawdust, borax, zinc borate, aluminium hydroxide, or any mixture of any two or more thereof. Preferred fillers include talc, calcium carbonate, clay, zeolite, bark (including pine bark), or any mixture of any two or more thereof In one embodiment the beads comprise about 1, 5, 10, 15, 20 or 25% filler. It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. The term “comprising” as used in this specification means consisting at least in part of that is to say the feature or component that something is said to consist of will be present but other features or components may also be present. Related terms such as “comprise” and “comprised” are to be interpreted in the same manner. DETAILED DESCRIPTION The advantages of present invention include that it is a simple process, that it allows the impregnated unfoamed beads to be stored and/or transported, that doesn't require a second re-impregnation step and that can be utilized as a ‘drop-in’ technology using much of an existing Expanded Polystyrene foam plant and equipment for pre-expansion and moulding and that it uses and produces ‘green’ products. Various aspects and embodiments of the method of the invention are described above. Polylactic acid or PLA is a polymer or copolymer comprising, consisting essentially of or consisting of lactic acid monomer units. For the purposes of the present invention references to polylactic acid includes homo-isomeric, hetero-isomeric, crystalline and amorphous polymers and mixtures of the aforestated. The PLA resin beads may comprise about 50-100% PLA by weight, including at least about 50, 60, 70, 80, 90, 95, 99 or 100% PLA by weight. The PLA may comprise amorphous PLA or a blend of amorphous PLA and crystalline PLA. Preferred blends comprise at least about 50, 60, 70, 80, 90, 95, 99 or 100% amorphous PLA by weight and about 0-50% crystalline PLA by weight, including at least about 0, 1, 5, 10, 20, 30, 40 or 50% crystalline PTA by weight. The lactic acid in the resin beads may comprise one or more lactic acid isomers including L-lactic acid, D-lactic acid or DL-lactic acid. Preferably the lactic acid is L-lactic acid. PLA is produced industrially by polymerization of lactic acid obtained by the bacterial fermentation of biomass such as beet, sugarcane, cornstarch or milk products. The PLA may also be blended with other additives, fillers or polymers. It should be noted that the process when utilized using industrially practical temperature and pressure ranges, is less effective when applied to highly crystalline grades. In one embodiment the PLA resin beads comprise a filler. Suitable fillers are known in the art and may be identified by a skilled worker with regard to that skill and the teachings of this specification. Preferred fillers are inert and biodegradable. In one embodiment fillers include but are not limited to talc, calcium carbonate, calcium stearate, sand, charcoal, clay, zeolite, bark (including pine bark), sawdust, borax, zinc borate, aluminium hydroxide, or any mixture of any two or more thereof. Preferred fillers are talc, calcium carbonate, clay, zeolite, bark (including pine bark), or any mixture of any two or more thereof. Most known impregnation techniques for PLA use gaseous or supercritical CO 2 . However, these have disadvantages over the present invention. In regard to supercritical CO 2 impregnation higher pressures are required (supercritical conditions require at least 7.4 MPa and 31° C.) and, further, the individual PLA granules tend to fuse into a single lump during impregnation as the CO 2 behaves as a very efficient plasticizer, thus lowering the glass transition temperature (Tg) of the PLA. Reducing the pressure after impregnation, due to the size of the pressure reduction, can cause an instantaneous foaming of the impregnated granules while still in the reactor resulting in one big lump unless temperatures also are greatly reduced. In regard to gas phase impregnation, gas conditions generally require much longer time frames to achieve equilibrium CO 2 concentrations compared to supercritical and liquid impregnations. In addition, particles still have a profound tendency to stick together during impregnation. After impregnation it is difficult to separate the agglomerates into individual granules. In liquid CO 2 impregnation the beads have little tendency to stick to each other. Liquid impregnation requires moderate temperature and pressure, e.g. 5 to 15° C. and preferably 10° C. and 5 to 8 MPa, preferably 6 MPa, and yields high CO 2 concentrations in the PLA granules, typically around 30% by weight (30 wt. %) and usually in the range of 18-35% by weight. Despite the high loading, the beads do not stick together and after releasing the pressure from the impregnation reactor they can be handled as a bulk commodity. Commercially available PLA resin beads can be impregnated without any pre-treatment using liquid CO 2 . Amorphous, crystalline, and amorphous-crystalline blends may be used but results with highly crystalline grades are sometimes of lesser quality at the preferred pressure and temperature ranges. Reference to resin “beads” generally means the crude resin material (often in the form of pellets) obtained from manufacturers and the terms beads, granules and pellets may be used interchangeably. Beads may be resized by extrusion and billing of the commercially available material using known techniques. A preferred means for impregnating the beads is by placing the beads in a pressure vessel under 6 MPa pressure and at 10° C. and then filling the pressure vessel with liquid CO 2 until the PLA beads are submerged. The PLA granules are left submerged in the liquid CO 2 until the carbon dioxide-PLA absorption equilibrium is substantially attained. Going to equilibrium results in the CO 2 blowing agent being dispersed evenly throughout the impregnated bead resulting in more even foaming and better cell structure when compared to other known processes that only take the beads to about 10 or 12 wt. %. Achieving equilibrium takes approximately 30-90 minutes when using NatureWorks™ PLA Polymer 4060D™ (NatureWorks LLC, USA), a commonly available commercial amorphous grade but may take longer or shorter depending on the size of the beads and the grade and composition of the beads. After substantially achieving equilibrium at the preferred temperature and pressure ranges, the beads comprise about 18-35% CO 2 by weight. When using NatureWorks™ PLA Polymer 4060D™ and CO 2 at 6 MPa and 10° C. equilibrium results in the beads having around 30 wt. % CO 2 . The liquid CO 2 is then removed (and can be recycled for re-use for impregnating the next batch of beads), and the pressure released until it reaches the ambient pressure. In other embodiments of the invention the beads may be retained and/or stored under higher than ambient pressure. The impregnated beads are then stored at a temperature below the minimum foaming temperature. The minimum foaming temperature will depend on the given pressure and the amount of CO 2 in the PLA-CO 2 matrix as CO 2 has the effect of lowering the glass transition and minimum foaming temperatures. At atmospheric pressure the beads must be stored in a refrigerated condition. A standard freezer at −18° C. or −20° C. is generally sufficient. In those conditions, in the first 24 hrs of storage, approximately 50%-75% of the CO 2 may be desorbed from the beads. Subsequently, the CO 2 loss reduces to a very moderate rate and the beads may be stored in a freezer for several weeks before being further processed. For expansion (often referred to as “foaming”), the preferred CO 2 concentrations are in the vicinity of 5 to 18 wt. % and around 10 wt. % is preferred. The CO 2 released during this storage time can be collected and compressed for re-use within the impregnation process. The impregnated beads may be pre-expanded immediately, stored then pre-expanded, pre-expanded then moulded (expanded and fused), moulded immediately, or stored then moulded. Absorbed CO 2 has the effect of reducing the glass transition temperature and therefore the amount of absorbed CO 2 affects the minimum foaming temperature of PLA. Pre-expansion is conducted at different temperatures and for different times according to the individual foaming characteristics of impregnated beads which in turn depends on blend and CO 2 percentage and the differences in minimum foaming temperatures that are the consequence of these factors. Preferably the pre-expansion is conducted at temperatures ranging from 20° C. to 110° C. at ambient pressure and more preferably commercially available amorphous PLA beads having been impregnated to about 30 wt. %-CO 2 , refrigerated until the CO 2 percentage reduces to 5-12%, and pre-expanded at 50-70° C. The pre-expansion step generally results in up to about 85-95%, preferably about 90%, of possible expansion. The purpose of this step is to expand the beads before the mould is sealed. Moulding without pre-expansion may require longer mould residence times and therefore may be less desirable. In many regards the pre-expansion and fusing stages of the present invention are similar to the well known Expanded Polystyrene (“EPS”) process and to known methods of foaming and moulding PLA. There is one significant difference. EPS and known PLA methods require a certain time period (called stabilization, aging, or the like) after pre-expansion but before fusing during which the pre-expanded beads are subjected to ambient conditions (sometimes with reduced humidity) to remove negative pressure within the foam pores, thus improving fusion during the subsequent moulding. A consequence of this is the loss of blowing agent and the pre-expanded beads generally require re-impregnation with blowing agent or some other gas before being inserted into a mould and fused. The method of the present invention does not require a “stabilization period” or re-impregnation. Rather, any prolonged time-period between pre-expansion and fusing reduces the quality and extent of the fusion. The pre-expanded beads are promptly transferred into a mould and steam (or other heating providing a temperature greater than the pre-expansion temperature) is applied to further expand the beads and fuse them together in the mould. A vacuum may also be applied before cooling and removal from the mould. The mould is preferably adapted to produce a moulded product including moulded blocks and shaped moulded products, especially blocks adapted to form packing material and shaped moulded products in the form of packaging material or convenience items such as packaging and storage products. Preferred convenience items include containers such as clamshell containers, pots, boxes, bowls, cups, plates and trays. A person skilled in the art will be aware that the absorption percentages, temperatures and pressures can be manipulated relative to each other at the different stages of the method of the invention to achieve substantially the same result with the major limiting factors being the preference for keeping the CO 2 weight percentage within or close to the optimum range of percentages, avoiding the excessive formation of dry ice in the pressure vessel, and retaining control of the foaming steps. Various aspects of the invention will now be illustrated in non-limiting ways by reference to the following example. EXAMPLES General Protocol Unless otherwise stated, the following general protocol was followed. The Polylactic acid material (NatureWorks LLC, USA) was pre-dried using an oven at 45° C. overnight. Other drying procedures are equally applicable as are commonly used in plastic, foam or other polymer processing. The PLA material, typically as pellets or particles, was placed in a pressure vessel suited to withstand the required pressure and temperature ranges. In some experiments, the size of the beads was altered from the commercial format and/or fillers or other additives were included (e.g. zinc stearate (a non-stick additive), talc, calcium carbonate, bark, clay, or zeolite) Liquid CO 2 was introduced into the vessel to the required pressure (e.g. about 5-8 MPa) or amount. The vessel was heated to the required temperature (e.g. 5-15° C.). After a period of a few minutes or after the pressure had stabilized, additional CO 2 was added or CO 2 was released as necessary to achieve the target pressure for impregnation with liquid carbon dioxide (e.g. about 5-8 MPa). After the period of time for impregnation (e.g. about 10 to 240 minutes, optionally longer—overnight, for example) CO 2 pressure was released and the vessel removed from temperature control. The impregnated beads were weighed before and after impregnation to calculate % CO 2 by weight. In some cases, the impregnated beads were used directly in an integrated moulding process with or without pre-expansion. Alternatively, the impregnated beads were stored in refrigerated conditions, for example in a standard freezer at −18° C., and then subjected to pre-expansion and moulding or moulding without pre-expansion. The impregnated beads, either directly after impregnation or later after storage, are then fused by application of heat in suitable mould. A pre-expansion step may be used to pre-expand the beads before expansion and fusing. The pre-expansion step may be conducted before the beads are introduced to the mould or may be conducted in the mould. The pre-expansion step involves heating the impregnated beads for a short period (e.g. about 5 to 120 seconds) at a suitable temperature (19-110° C. for example). Once impregnated or pre-expanded beads are added to the mould, a combination of steam heating (about 50 to 100° C., for about 5 to 120 seconds for example) and optional vacuum (for about 1 second to 10 minutes for example) was applied to expand and fuse the beads. Steam and optionally vacuum are applied for a short time (e.g. 2 to 10 minutes) to fuse the impregnated beads and fill to the mould shape, to make a foam block of uniform foam structure. Cooling may be applied before de-moulding, using water cooling of the mould for example. Average block density can be readily calculated from the weight and dimensions of the block. Block density is preferably measured 48 hours after moulding by which time the CO 2 levels have stabilized. All references to % CO 2 concentrations in the examples are references to percent CO 2 by weight relative to the combined weight of the PLA material and CO 2 . Example 1 Commercial PLA beads and blends of commercial PLA beads were inserted into a pressure vessel (impregnation equipment) with the beads in close contact. No stirring nor dispersion medium nor stabilizing agents were used. The PLA resin beads used were NatureWorks™ (NatureWorks LLC, USA) PLA Polymer 4060D™. Subsequent runs were conducted using 5:1 and 1:1 blends of NatureWorks™ PLA Polymer 4060D™ (amorphous) and NatureWorks™ PLA Polymer 3001™ (highly crystalline) (NatureWorks LLC, USA). The pressure vessel was filled with liquid CO 2 and PLA beads submerged under 6 MPa pressure and at 10° C. The PLA granules were left submerged in the liquid CO 2 for approximately 90 minutes until reaching (CO 2 absorption) equilibrium. After 90 minutes the PLA beads and CO 2 achieved equilibrium with the PLA beads incorporating around 30 wt. % CO 2 . The liquid CO 2 was removed and the pressure released until it reached ambient. The impregnated beads were stored in a freezer (at −20° C.) for 24 h. During this time 50%-75% of the CO 2 was desorbed from the beads. Subsequently, the CO 2 loss reduced to a very moderate rate. The beads were stored in the freezer for a month before being further processed. After storage the beads having 10 wt. % CO 2 were pre-expanded at temperatures of 50-70° C. Without a re-impregnation step, the beads were directly transferred and blown into a mould and then further expanded and fused in the mould. A water boiler in combination with a water-ring vacuum pump provided the steam at required temperatures and pressures and vacuum pump provided vacuum. After applying steam and vacuum the mould was water cooled for one minute. The mould was dismantled to remove the moulded product. The moulded product of fused foamed (expanded) PLA beads consisted of consistently expanded and fused beads with substantially uniform foam structure and fully filled the mould. Example 2 Expansion Test, PLA 4060D™ Liquid Impregnation for 30 Min PLA 4060D™ beads were impregnated at 10° C., 6 MPa pressure for 30 min as per the protocol above. Average CO 2 concentration of the beads after impregnation was 25.46% by weight. Hard core* was found, when tried to foam immediate after impregnation and 27 h after storing in freezer, in hot water at different temperatures (20° C., 50° C. and 80° C.). The hard core disappeared when the beads were stored in the freezer for 45 h and foamed in hot water at 80° C. for 40 seconds. The CO 2 concentration of the expanded beads was 6.57%. The beads expanded very well and had a density of 38 g/l. Hard core: Unfoamed solid polymer remaining at the centre of the bead after foaming. Due to unfoamed solid polymer, the density of the foam bead will be higher. When the hard core disappears and the whole bead foams, the density will be lower Example 3 Expansion Test, PLA 4060D™ Liquid Impregnation for 60 Min Impregnation of PLA 4060D™ beads was performed at 10° C., 6 MPa pressure for 60 min as per the protocol. Average CO 2 concentration of the beads after impregnation was 29.82%. Hard core was found, when tried to foam immediate after impregnation and 1 h after storing in freezer, in hot water at different temperatures. The hard core disappeared, after storing in freezer for 18 h and foamed in hot water at 80° C. for 40 s. CO 2 concentration of the beads was 13.51%. The beads expanded very well. Density of the beads was 38 g/l. It was found that sufficient CO 2 retention was able to be realized up to at least 48 hrs at −18 C without any other attempts to retain CO 2 and good quality expanded beads could be obtained—see Table 1. TABLE 1 CO 2 concentrations after storage at −18° C. Time in freezer CO 2 concentration on (hour) removal (wt. %) 0 29.82 1 21.82 18 13.51 25 12.59 42 11.24 48 10.87 Example 4 Expansion Test, PLA 4060D™ Liquid Impregnation for 90 Min Impregnation of PLA 4060D™ beads was carried out at 10° C., 6 MPa pressure for 90 min as per the protocol. Average CO 2 concentration of the beads after impregnation was 30.30%. Impregnated beads were expanded immediately after impregnation using hot water at 50° C. for 40 s or at 80° C. for 1 min. Impregnated beads were also stored in a freezer and the average CO 2 concentration of the beads after storage in the freezer for 19 hr was 13.73% and the average CO 2 concentration of the beads after storage in the freezer for 42 hr was 11.83%. All such beads could be expanded at 80° C. for 1 min. The average density of these beads was 35 g/l. Example 5 Block Production, PLA 4060D™ Larger Beads and Liquid Impregnation PLA 4060D™ beads were first extruded on a standard laboratory twin screw extruder into cooled strands (air cooled) and pelletized into larger pellets than typically received in commercial PLA material. The extruded pellets were about 4-6 mm, compared to those typically received from NatureWorks LLC that were about 3-4 mm). These larger beads were dried and impregnated at 10° C., 6 MPa pressure for 3 hr as per the above examples and protocol. The average CO 2 concentration of the beads was 27.63%. A block was made after storing impregnated beads in a freezer for 43 h as per the protocol above. The CO 2 concentration of the beads after storage was 12.78%. Impregnated beads were pre-expanded in hot water at 70° C. for 90 s and fused together in a metal mould by applying steam at 86° C. for 90 s. The average density of the block was ˜30 g/l. Example 6 Block Production, PLA 4060D™ Smaller Beads and Liquid Impregnation PLA 4060D™ beads were extruded and pelletized to make smaller beads. Cooled (water cooled) strands of extruder polymer were collected and pelletized (1-2 mm) (compared to those from NatureWorks of 3-4 mm). The smaller beads were dried at 45° C. overnight. Optionally a small amount (for example in this case, 0.140%) of anti-stick additive such as zinc stearate could be added prior to impregnation, or during extrusion. Impregnation was carried out at 10° C., 6 MPa pressure for 2 hr as per the protocol. The average CO 2 concentration of the beads was 29.31%. A moulded block was made after storing impregnated beads in the freezer for 17 hrs as per the above protocol. The CO 2 concentration of the beads after storage was 11.62%. Impregnated beads were pre-expanded in hot water at 69° C. for 1 min and fused together in a metal mould by applying steam at 80° C. for 20 s. The block formed was very good and its density was ˜42 g/l. Example 7 Block Production, PLA 4060D™ and PLA 8302D™ Liquid Impregnation Dried PLA 4060D™ or PLA 8302D™ (amorphous) beads were impregnated at 10° C., 6 MPa pressure for 2 h as per the protocol above. The average CO 2 concentration of the beads was 32.42% and 31.03% for PLA 4060D™ and PLA 8302D™ impregnated beads respectively. Fused blocks were made from impregnated beads after storing in the freezer for 22 h and for 46 hrs as follows. PLA 4060D™ (after 22 h in freezer) exhibited an average CO 2 concentration of 13.18% and impregnated beads were pre-expanded at 70° C. for 40 s, and then fused at 80° C. (65 s) with steam and vacuum (5 min). The block formed was cooled with tap water. The density of the fused block was ˜44 g/l. The mould was fully filled and the block was good. PLA 8302D™ (after 22.50 h in freezer) exhibited an average CO 2 concentration of 13.40%. The impregnated beads were pre-expanded at 70° C. for 40 s, and then fused in a mould at a steam temperature of 80° C. for 65 s, with applied vacuum and then cooling (ambient water). Block density was ˜44 g/l. The mould was not fully filled. PLA 4060D™ beads (after 46 h in freezer) exhibited a CO 2 concentration of 11.24%. The impregnated beads were pre-expanded at 70° C. for 50 s and then fused in a mould at a steam temperature of 80° C. for 75 s, with application of vacuum and subsequent cooling to make a fused foam block. The mould was fully filled and the block looked good. PLA 8302D™ (after 46.50 h in freezer) exhibited a CO 2 concentration of 11.63%. Impregnated beads were pre-expanded at 70° C. for 50 s and then successfully fused in a mould as above at 80° C. for 75 s. The mould was not fully filled. Example 8 Block Production, PLA4060D™ 75° C. Moulding PLA 4060D beads were impregnated at 10° C., 60 bar pressure for 4 hours as per the protocol above. The average CO 2 concentration of the beads after impregnation was 28.08%. The beads were then stored in a freezer for 48 h. The average CO 2 concentration of the beads after storing was 11.21%. The impregnated beads were then pre-foamed in hot water at 80° C. for 15 seconds and then fused using steam at 75° C. for 1 minute, followed by 6 minutes vacuum and 1 minute cooling. The beads were fused together well and the block was good. The density of the foam block was 55 g/l. Example 9 Block Production, 10-30% Talc by Weight Extruded with PLA 4060D™ 10, 20 or 30% talc (by weight of the talc and PLA) was compounded with PLA 4060D™ using extrusion compounding. Air cooled strands were pelletized and dried in an oven at 45° C. overnight prior to impregnation at 10° C., 6 MPa pressure for 2.5 h as per the protocol. The average CO 2 concentration of the beads was 25.80%, 2519% and 23.42% for 10%, 20% and 30% beads respectively. Impregnated beads were pre-expanded at 70° C. and fused together using steam at 80° C. in a metal mould as per the protocol. The block comprising 10% talc was of good quality and consistency. The beads comprising 30% talc shrunk and did not fuse during moulding. For 10% talc extruded with PLA 4060D™, the CO 2 concentration after 26 h in freezer was 10.59%. The beads were pre-expanded at 70° C. for 40 s and Fused in a mould at 78° C. for 65 s. The density of the block was 53 g/l Similarly 20% talc was extruded with PLA 4060D™ impregnated as above and stored (26 h in freezer). The CO 2 concentration after 26 h in the freezer was 10.69% Beads were pre-expanded at 70° C. for 40 s. Moulding was at 80° C. for 65 s. Although some shrinkage of expanded beads had occurred good quality fused blocks could be made. The density of the blocks after 24 hr at 45° C. and 24 hr at room temperature was 46 g/l. 10% talc extruded with PLA 4060D™ (after 48 h in freezer). The CO 2 concentration after 48 h in the freezer was 10.59%. Beads were pre-expanded at 70° C. for 40 s and moulded successfully at 79° C. for 55 s. The block was good and the density of the block was 59 g/l after 24 hr at 45° C. and 24 hr at room temperature. Example 10 Block Production, Calcium Carbonate Extruded with PLA 4060D™ 10% or 20% calcium carbonate (by weight of the calcium carbonate and PLA) was compounded with PLA 4060D™ using extrusion. Air cooled strands were pelletised and dried in an oven at 45° C. overnight prior to impregnation at 10° C., 6 MPa pressure for 3 hr as per the protocol. The average CO 2 concentration of the beads following impregnation was 25.62% and 24.80% for 10% and 20% extrusion compounded granules of calcium carbonate with PLA 4060D™ respectively. Foam blocks were made as per the protocol as follows. 10% calcium carbonate beads had a CO 2 concentration after 24 h in the freezer of 11.82%. Beads were pre-expanded at 70° C. for 30 s and moulded at 79° C. for 55 s. The density of the block after 24 hr in a 45° C. oven was 56.3 g/l. The block was good. 10% calcium carbonate beads had a CO 2 concentration after 24 h in the freezer of 11.43%. Beads were pre-expanded at 70° C. for 30 s and moulded at 79° C. for 55 s with application of vacuum for 6 minutes and water cooling. The density of the block after 24 hr in a 45° C. oven was 53.9 g/l. The block was good. 20% calcium carbonate beads had a CO 2 concentration after 24 h in the freezer of 10.17%. Beads were pre-expanded at 70° C. for 20 s and moulded at 78° C. for 50 s with vacuum for 6 minutes and water cooling. The density of the block after 24 hr in a 45° C. oven was 67.89 g/l. The block was acceptable. Example 11 Block Production, Pine Bark and PLA 4060D™ 10% and 20% ground pine bark (by weight of the bark and PLA) were blended with PLA 4060D™ using extrusion compounding. Air cooled strands were pelletised and dried in an oven at 45° C. overnight prior to impregnation at 10° C., 6 MPa pressure for 2.5 hr as per the protocol. The average CO 2 concentration of the beads was after impregnation was 26% and 27.5% for 10% and 20% extrusion compounded granules of bark with PLA 4060D™ respectively. Blocks were moulded according to the protocol as follows. 10% bark beads had a CO 2 concentration after 24 h in the freezer of 11.25%. Beads were pre-expanded at 70° C. for 25 s and then moulded at 78° C. for 55 s. The expanded block was good quality and had a density (after 48 hr) of 38 g/l. Other beads were pre-expanded at 70° C. for 15 s and then moulded at 79° C. for 60 s. The expanded block was good quality and had a density (after 48 hr) of 49 g/l. 20% bark beads had a CO 2 concentration after 24 h in the freezer of 11.16%. The beads were pre-expanded at 70° C. for 10 s and then moulded at 79° C. for 40 s. Vacuum was applied for 6 min. The expanded block was good quality and had a density (after 48 hr) of 66 g/l. Other beads were pre-expanded at 70° C. for 13 s and then moulded at 77° C. for 43 s. The expanded block was good quality and had a density (after 48 hr) of 56 g/l. Example 12 Block Production, Clay and Zeolite-PLA Compounds 5% clay or 10% zeolite (by weight of the clay and/or zeolite and PLA) were blended with PLA 4060D™ using extrusion compounding. Air cooled strands were pelletized and dried in an oven at 45° C. overnight prior to impregnation at 10° C., 6 MPa pressure for 3 h as per the protocol. The average CO 2 concentration of the beads was 35.56% and 33.40% for 5% and 10% extrusion compounded granules of 5% clay and 10% zeolite with PLA 4060D™ respectively. The beads expanded well, again with a fine cell structure, after storing in a freezer (−18° C.) for 48 hr. INDUSTRIAL APPLICATION The methods and compositions of the present invention have utility in packaging applications. Those persons skilled in the art will understand that the above description is provided by way of illustration only and that the invention is not limited thereto.

Method of forming a composition comprising impregnated polylactic acid (PLA) resin beads, by impregnating PLA resin beads with CO 2 . The method is carried out by contacting the beads with liquid CO 2 , and holding the impregnated beads at a temperature and pressure that prevents the beads from foaming while allowing the level of impregnated CO 2 to reduce to about 4 to 20 weight % relative to the total weight of the beads and CO 2 .

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a sanitary facility room to be installed in a computer room or a clean room found in a semiconductor element manufacturing factory or the like. 2. Description of the Prior Art In a conventional type of such clean room, a sanitary facility room having some sanitary equipment such as toilet bowls and hand washing bowls or the like installed therein was not arranged in the clean room, but installed outside of the clean room, so that its use was quite inconvenient. The sanitary facility room was not mounted in the clean room because splashed stain water or adhered filth during use of sanitary facility generates dust after they become dried, or because manual operation of the plug during washing operation caused some hand stains to adhere to the operating part of the plug due to the relative by frequent operation of the plug, and because the hand stains might float in the sanitary facility room as dust, and at the same time odor or dust in the sanitary equipment stay in the air. Further, in case of the toilet bowl, a user uses toilet paper after utilizing the toilet bowl and in the case utilizing a hand washing bowl, the user might use a towel after its utilization, resulting in the generation of dusts from the toilet paper or towel or the like floated in the sanitary facility room and accumulated in it, and these dusts were adhered to the clothes of the user and brought into the clean room. SUMMARY OF THE INVENTION With the foregoing in mind, the present invention may accomplish the following objects. That is, it is an object of the present invention to provide a sanitary facility room for a clean room in which a splashing of sewage or adhesion of filth during use of the sanitary facility is prevented and the occurrence of dust can be prevented. It is another object of the present invention to provide a sanitary facility room for a clean room in which user can utilize the sanitary facility without touching it with his hands at all. It is still a further object of the present invention to provide a sanitary facility room for a clean room in which a user can completely utilize the sanitary facility without using any toilet paper or towel even after utilization of the facility. It is still a yet further object of the present invention to provide a sanitary facility room for a clean room in which odor in the toilet bowl or dust in the hand washing bowl can be discharged. It is still further object of the present invention to provide a sanitary facility room for a clean room in which the sanitary facility equipment can easily be installed on site. The above-mentioned first object can be accomplished by a method wherein a water feeding part is operated during use of the sanitary facility, washing water is fed to the sanitary facility, and a water film is formed at the inner surface of sanitary facility. The above-mentioned second object can be attained by a method wherein the water feeding part is operated in response to a human sensing operation at a sensing part. The above-mentioned third object can be accomplished by a method wherein the toilet bowl is provided with a local washing and drying device for cleaning and drying a local part of a human body and further a hand washing bowl is provided with a hot air supplying device for use in drying the hands. The above-mentioned fourth object can be attained by a method wherein the toilet bowl and the hand washing bowl are provided with an air bleeding device for discharging interior air, respectively. The above-mentioned fifth object can be accomplished by a method wherein a functioning part and a control part for the water feeding part are fixed and arranged in the fixing frames which are integrally assembled at the rear part of the sanitary instrument, or from its bottom part to its upper part through the rear part, and these functioning and control parts of the water feeding part are covered by cover panels which are fixed between the fixing frames. BRIEF DESCRIPTION OF THE DRAWINGS Other objects and features of the present invention will become apparent from the following description taken in conjunction with the attached drawings. FIG. 1 is a perspective view in section for showing a sanitary facility room for a clean room for illustrating one preferred embodiment of the present invention. FIG. 2 is a perspective view for showing a toilet bowl. FIG. 3 is a longitudinal side elevation view of FIG. 2. FIG. 4 is a cross sectional top plan view of FIG. 2. FIG. 5 is a side elevation view partly broken away for showing an enlarged sensing part. FIG. 6 is an enlarged front elevation view for showing an operating part. FIG. 7 is an enlarged front elevation view for showing a water force adjusting control panel. FIG. 8 is a time chart for use in performing a cleaning of a toilet bowl. FIG. 9 is a time chart for use in performing a local cleaning and drying operation. FIG. 10 is a flow chart for use in performing a cleaning of toilet bowl, a local cleaning and a drying operation. FIG. 11 is a longitudinal side elevation view for showing another preferred embodiment of a toilet bowl. FIG. 12 is a cross sectional view in top plan of FIG. 11. FIG. 13 is a longitudinal side elevation view for showing a toilet bowl. FIG. 14 is a front elevation view partly broken away. FIG. 15 is a top plan view partly broken away. FIG. 16 is a side elevation view partly broken away for showing an enlarged fixing structure for a sensing part. FIG. 17 is a time chart for use in performing a cleaning of a toilet bowl. FIG. 18 is a flow chart of for performing a cleaning operation. FIG. 19 is a longitudinal side elevation in section for showing another preferred embodiment of a toilet bowl. FIG. 20 is a front elevational view of FIG. 19. FIG. 21 is a longitudinal side elevational view for showing a hand washing bowl. FIG. 22 is a front elevational view of FIG. 21. FIG. 23 is an enlarged front elevational view for showing a control panel for use in performing a manual control. FIG. 24 is a time chart for use in performing manual control. FIG. 25 is a flow chart for use in performing manual control. FIG. 26 is a time chart for use in performing manual control. FIG. 27 is a flow chart for use in performing manual control. FIGS. 28 and 29 are longitudinal side elevations, in section for showing another preferred embodiment of a hand washing bowl. FIG. 20 is a time chart for use in performing an automatic control. FIG. 31 is a flow chart for use in performing automatic control. FIG. 32 is a time chart for use in performing manual control. FIG. 33 is a flow chart for use in performing manual control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In reference to FIG. 1, one preferred embodiment of the present invention will be described. This figure shows a case in which a toilet bowl (a), a toilet bowl (b) and a hand washing bowl (c) are arranged in a unit room (A). The unit room (A) is formed with an air passage (A 4 ) communicating with the interior of its floor (A 1 ), interior of a side wall (A 2 ) and interior of a ceiling (A 3 ), and a grating (A 5 ) having several vent holes therein is arranged over an entire floor surface, and in turn an entire ceiling wall is provided with air filters (A 6 ). Interior air is forcedly circulated by a circulation blower (A 7 ) arranged midway in the air passage (A 4 ), thereby clean and fresh air is always supplied through air filters (A 6 ) and the atmosphere in the room is kept clean. Each of the air filters (A 6 ) is a high grade filter which can collect dusts from ultra fine particles, and its efficiency of collection is more than 99.7%. The toilet bowl (a) is provided with a water supplying part (1) for cleaning the interior of the toilet bowl (a) as shown in FIGS. 2 to 4 and, a local cleaning device (2) and local drying devices (3) constituting a local cleaning and drying device for use in cleaning a local part of a user and thereafter drying the local part, an air bleeding device (4) for discharging odor in the toilet bowl (a), and a control part (6) for receiving a sensing signal from a sensing part (5) for sensing a human body and a signal from a operating part (7) for controlling each of the operations of the devices. The water supplying part (1) is made such that a water passage (1a) communicating with a source of water is formed at an outer circumference of the toilet bowl (a), a water supplying pipe (1b) is connected to the water passage (1a), a solenoid valve (1c) is arranged midway in of the water supplying pipe (1b), the solenoid valve (1c) is electrically connected to the control part (6), the solenoid valve (1c) is opened for a predetermined perod of time under an instruction from the control part (6), cleaning water is supplied to the water passage (1a) from the water supplying pipe (1b), and cleaning water flows along the inner wall of the toilet bowl (a) from several water flowing ports (1d) open at the bottom wall of the water passage (1a) so as to clean the toilet bowl (a). The water supplying pipe (1b) and the solenoid valve (1c) are placed out of the unit room (A), so as not to hinder the flow of the clean air in the unit room (A) and then they are connected to the source of water. Cleaning water from the water supplying part (1) and sewage in the toilet bowl (a) are discharged out of the unit room (A) through a drain trap (1e) and a drain pipe (1f) connected to the drain trap. The local cleaning device (2) is made such that a cleaning water injection nozzle (2a) is arranged at the lower surface of seat (A1), the nozzle (2a) is connected to the source of hot cleaning water through the water supplying pipe (2b) and the solenoid valve (2c), solenoid valve (2c) is electrically connected to the control part (6), solenoid valve (2c) is opened under an instruction from the control part (6), cleaning water of desired temperature is supplied to the cleaning water injection nozzle (2a) through the water supplying pipe (2b), and the nozzle (2a) injects cleaning water toward the local part of the user so as to clean the local part. The cleaning water injection nozzle (2a) can be extended out or retracted from an opening (a2) of seat (a1), and it is set such that it projects with respect to the opening (a2) an amount which is different during each anus cleaning and bidet-type cleaning, respectively. The water supplying pipe (2a) and the solenoid valve (2c) are out of the unit room (A) due to reasons similar to those in the case of the toilet bowl cleaning device. Local drying devices (3) are made such that hot air passages (3a) are defined within seat (a1), in which the passages (3a) are connected to a hot air generating machine (3c) through air feeding pipes (3b) for guiding passages out of the unit room (A), and the hot air generating machine (3c) is electrically connected to control part (6). The hot air generating machine (3c) is operated under instructions from the control part (6) to feed hot air to the hot air passages (3a), and hot air is injected toward the local part of the user from injection ports (3d) opened at the front end walls of the passages (3a) so as to dry the local part of the user. The hot air generating machine (3c) is placed out of the unit room (A), and within the casing (32c) to which the suction pipe (31c) is connected are sequentially arranged a blower fan (33c), an air filter (34c) having a high efficiency of collection, and a ceramic heater (35c) generating no oxides; and further the hot air generating machine has a lower thermal loss and can supply clean hot air in such a way so that the air does not pollute the interior of the unit room (A). An air bleeding device (4) is made such that an air bleeding passage (4a) is defined at an outer circumference of the seat (a1), bleeding passage (4a) is communicated with the forced discharging fan (4c) through discharging pipes (4b) for guiding passages out of the unit room (A), the bleeding fan (4c) is electrically connected to the control part (6), the forced discharging fan (4c) is operated under instructions from the control part (6), odor in the toilet bowl (a) is suctioned from the suction port (4d) opening to the bottom wall of the discharging passage (4a) and is then discharged out of the unit room (A). A sensing part (5) comprises a photoelectric sensor which is fixed at the rear upper position of the toilet bowl (a) at the rear wall (A 8 ) of the unit room (A), and which is electrically connected to the control part (6). The sensor detects a human body during use of the toilet bowl, sends a sensed signal to the control part (6) and verifies to the control part (6) that beginning of the use of the toilet bowl has occurred. The sensing part (5) is made such that as shown in FIG. 5 a light emitting and receiving element (5a) is inclined forwardly and downwardly, a sensing area is restricted near the toilet bowl (a), and an erroneous operation is prevented in such a case as, for example, other than the use of toilet bowl, i.e., when a man merely passes by in front of the toilet bowl (a), it may not detect the human body. The operating part (7) is used for making a manual changeover operation between the local cleaning device (2) and the local drying devices (3), wherein as shown in FIG. 6, a photoelectric sensor (7a) is assembled in the operating panel (7b) and arranged at the upper side position of the toilet bowl (a) at the side wall (A 2 ) of the unit room (A). The operating part is electrically connected to the control part (6) and the photoelectrical sensor (7a) detects the hands of the user during a change-over operation and sends the sensed signal to the control part (6). That is, every time the user places his hands in front of the photoelectrical sensor (7a), operations of the local cleaning device (2) and the local drying devices (3) change over among a local cleaning, cleaning with bidet, drying, and stop. Operation of the operating part (7) is allowed only when the sensing part (5) is operated, operation other than use of toilet bowl sensed by the sensing part (5) is prohibited, and cleaning water is prevented from accidentally being injected at the cleaning water injection nozzle (2a) in the local cleaning device (2) other than during occasional use of the toilet bowl, water is further prevented from staining unit room (A). Receipt of a signal sent from the operating part (7) to the control part (6) is cancelled when a signal output time is within a desired period of time, e.g., less than 0.5 seconds; subsequent signals are also cancelled when the output interval of signals is less than a desired period of time, e.g. less than 1 second, and operations of the local cleaning device (2) and the local drying device (3) are not unnecessarily changed over. The operating panel (7b) is provided with a display for indicating operating conditions of the presence or the absence of the power supply input ranging from the cleaning to stop, and is provided with light emitting diodes (7c) near the display for indicating the operations. At a position near the operating panel (7b) a water force adjusting operating panel (8) is arranged for use in adjusting the water force from the cleaning water injection nozzle (2a) in the local cleaning device (2). The operating panel (8) is provided with water force adjusting switches (8a) and (8b) as shown in FIG. 7. The switches (8a) and (8b) are so-called manual touch switches. These switches are relatively less frequently used and only a part of the finger tip is contacted with the switches, so the slight adhesion of hand stains may not generate any troubles at all. Operations of the toilet bowl (a) during its use described above are performed in reference to the time chart and the flow chart as shown in FIGS. 8 and 10. That is, the user sits on the seat (a1), the sensing part (5) detects the human body and the sensed signal is sent to the control part (6). This sensed signal is cancelled, within a desired time, e.g. within tree seconds, and useless operation of the water supplying part (1), local cleaning device (2) and the local drying devices (3) are prevented. When the sensed signal is fed to the control part (6) for more than three seconds, the solenoid valve (1c) of the water supplying part (1) is opened and a preparatory cleaning of the toilet bowl (a) is carried out; and, at the same time, the power supply for the operating part (7) is turned on. Further, when the sensing part (5) detects the human body, at the same time the forced discharging fan (4c) for the air bleeding device (4) is operated, and the discharging or bleeding of odor is started under suction at the suction port (4d). The reason why the preparatory cleaning is performed consists in the fact that water film is formed at the inner wall surface of the toilet bowl (a) in advance, and so that stains after use of the toilet bowl may easily be removed. And the bleeding operation is continued during the use of the toilet bowl in such a way that odors can be discharged without leaving them as well as for a desired period of time, for example, 15 seconds after the user has moved away from the toilet bowl, upon completion of the use of the toilet bowl, cleaning of the local part; and drying of the local part and even after the output of the sensed signal of the sensing part (5) is stopped and after output of the sensed signal is stopped. Upon completion of use of the toilet bowl, the user sets his hands in front of the photoelectric sensor (7a) at the operating part (7) to cause the sensor (7a) to detect the hands; thereby, the local cleaning device (2) starts to operate with the output of the first sensed signal and the cleaning of the local part is carried out with the cleaning water injected from the cleaning water injection nozzle (2a). After completion of the local cleaning operation, a second sensing signal is outputted at the photoelectric sensor (7a) at the operating part (7) again during a manual operation and cleaning with a bidet can be carried out. After washing with a bidet, or in cases where cleaning with bidet is not required, a third sensing signal is subsequently outputted at the photoelectrical sensor (7a) of the operating part (7); thereby, the local drying devices (3) start to operate, hot air is blown from the blowing ports (3d), and then the local part is dried. A ceramic heater (35c) in the local drying devices (3) begin to heat when the sensing signal of the sensing part (5a) is outputted, and hot air is fed instantly by a blower fan (33c) when the drying operation is started. A fourth sensing signal is outputted at the photoelectric sensor (7a) of the operating part (7); thereby, operation of the local drying devices (3) is stopped and a light emitting diode (7c) for displaying a stopped condition in the operating panel (7b) is illuminated for about one second. Further, upon completion of cleaning after use of the toilet bowl and drying of it in such a manner as described above, when the user moves away from the toilet bowl (a), input from sensing part (5) to control part (6) is stopped, and the power supply for the operating part (7) is turned off and, at the same time the solenoid valve (1c) of the water supplying part (1) is opened again for a desired period of time under instructions from the control part (6) after a desired interval, for example, 2 seconds after the input of the signal is stopped. Thus, a major cleaning of the toilet bowl is carried out and sewage is discharged out of the toilet bowl (a). After the input of the sensed signal from the sensing part (5) is stopped and after a desired period of time, for example, 15 seconds, has elapsed, operation of the bleeding device is stopped and all of the operations are also stopped. In this way, under conditions in which all of the operations are stopped, that is, at a time other than during use of the toilet bowl, the power supply for the operating part (7) is kept turned off, so that the operating part (7) does not detect the human body so long as the sensing part (5) does not output any sensing signals; and it does not produce any outputs and thus, it is possible to prevent erroneous, i.e., unintended, operation of the local cleaning device (2) and the local drying devices (3). The local cleaning device (2) and the local drying devices (3) continue their operations within a desired period of time set by the control part (6) until the operating part (7) produces a new sensed signal, and stop automatically after the desired period of time is elapsed. The set time is set to, for example, 5 minutes in case of performing local cleaning and cleaning with bidet, and it is set at 10 minutes for example when performing a local drying operation. After the set time is elapsed, an alarm device will be operated after the local cleaning device (2) and the local drying devices (3) are stopped, and this alarm device will generate an alarm. FIGS. 11 and 12 illustrate another preferred embodiment of a toilet bowl (a), wherein fixing frames (9) are integrally assembled and formed at the rear part of the toilet bowl (a). Within the fixing frames (9) are fixed and arranged the water supplying part (1), local cleaning device (2), local drying devices (3), the functioning part of the discharging device (4), and the control part (6). Cover panels (10) are fixed between the fixing frames (9), thereby covering the functioning part of each of the devices and the control part (6) so as to make a unified assembly. The fixing frames (9) are assembled in a box-like form higher than the toilet bowl (a) and the seat (a1), a sensing part (5) is fixed to the cover panel (10) covering the front surface, and at the same time a code (6a) pulled out of the control part (6) can be connected to a power supply code (6b) arranged out of the cover panel (10). The functioning part of the water supplying part (1) corresponds to the water supplying pipe (1b) and the solenoid valve (1c), the base end of the water supplying part (1b) is passed through the cover panel (10) and projected outwardly and can be further connected to a main water supplying pipe (1h) through a connector (1g). The base end of drain pipe (1f) connected to the toilet bowl (a) is similarly passed through the cover panel (10), projected outwardly, and can be connected to the main drain pipe (1j) through a connector (1i). The functioning part of the local cleaning device (2) comprises the water supplying pipe (2b) and the solenoid valve (2c), except that a cleaning injection nozzle (2a) and a hot water heater (2d) is connected to the end of the water supplying pipe (2b) as shown in the drawings, and the hot water heater (2d) is mounted on and fixed to a mounting plate (2e) arranged within the fixing frames (9) and at the same time, the heater is connected to the midway part of the water supplying pipe (1b) of the water supplying part (1) through a branch pipe (2f). The functioning part of the local drying devices (3) comprises to the air blowing pipe (3b) and the hot air generating machine (3c), and the base end of the suction pipe (31c) of the hot air generating machine (3c) is passed through the cover panel (10), projected outwardly, and can be connected to the main suction pipe (3d). The functioning part of the bleeding device (4) comprises a bleeding pipe (4b) and a forced bleeding fan (4c), the base end of the bleeding pipe (4b) is passed through the cover panel (10) and projected outwardly and can be connected to the main bleeding pipe (4d). Therefore, the system shown in FIGS. 11 and 12 can be completed on site only by connecting a power supply code (6b), main water supplying pipe (1h), main drain pipe (1j), suction main pipe (3d) and bleeding main pipe (4d). Since this system has no troublesome operation, as found in FIGS. 3 and 4, in which the functioning part of each of the devices and the control part (6) are separately arranged and they must thereafter be connected to each other, the result is that their mounting work is quite simple and convenient. Now, a toilet bowl (b) will be described as follows. As shown in FIGS. 13 to 15, the toilet bowl (b) is provided with a water supplying part (11) for cleaning the interior of the toilet bowl (b) and a control part (13) for receiving a sensed signal from a sensing part (12) sensing the human body and for controlling the operation of the water supplying part (11). the water supplying part (11) has a water passage (11a) along an entire circumference of the opening (b1), the water passage (11a) is connected to a water supplying source through the water supplying pipe (11b) extending out of the unit room (A), a solenoid valve (11c) is arranged in the water supplying pipe (11b), the solenoid valve (11c) is electrically connected to the control part (13), and solenoid valve (11c) is opened under instructions from the control part (13), the cleaning water is supplied from the water supplying pipe (11b) to the water passage (11a). The cleaning water flows from several water flowing holes (11d) opening at the bottom wall of the water passage (11a) along the inner wall of the toilet bowl (b), so as to clean the interior of the toilet bowl (b). The cleaning water and sewage from the water supplying part (11) are discharged outwardly of the unit room (A) from the toilet bowl (b) through a drain trap (11e) and a drain pipe (11f). The sensing part (12) is comprised of a photoelectric sensor, detects a human body standing in front of the toilet bowl (b) when the toilet bowl is being used, sends the sensed signal to the control part (13), causes the control part (13) to acknowledge the starting of use of the toilet bowl, and the sensing part is fixed in a flush fashion, to the upper front wall (b2) of the toilet bowl (b) in such a way so that it will not hinder the flow of clean air within the unit room (A). A fixing structure for the sensing part (12) is constructed as shown in FIG. 16, wherein the sensing part (12) is inserted and fixed to a front wall (b2) of the toilet bowl (b) through a fixing hole (b3), a front end flange (12a) of the sensing part (12) is abutted against an outer surface of the front wall (b2) and, in turn a fixing threaded shaft (12b) at the rear end is fixed to the inner surface of the front wall (b2) through bracket (12c) and nut (12d). Operation of the toilet bowl (b) during use of the toilet bowl (b) as described above is performed with reference to the time chart and the flow chart shown in FIGS. 17 and 18. That is, when the user stands in front of the toilet bowl (b), the sensing part (12) detects the human body and sends the sensed signal to the control part (13). This sensed signal will be cancelled when the output has a desired period of time, for example, within three seconds, and useless operation of the water supplying part (11) will be prevented. When the sensed signal is inputted to the control part (13) for more than three seconds, the solenoid valve (11c) of the water supplying part (11) will be opened under instructions from the control part (13), and then cleaning of the toilet bowl (b) will be started before use the toilet bowl. The duration of the solenoid valve (11c) is one second, the solenoid valve (11c) is closed after the time of opening of the valve is elapsed, the valve will be opened again after six seconds, and periodic opening and closing operation of the solenoid valve (11c) is repeated several times within the period of use of the toilet bowl. The valve opening time or valve closing time of the solenoid valve (11c) is counted by a timer at the control part (13), and the solenoid valve (11c) is opened or closed with within the period of setting time at the control part. Thus, a proper amount of cleaning water is supplied into the toilet bowl (b) continously from a time before starting use of the toilet bowl until the time after completion of use of the toilet bowl under a periodic opening and closing operation of the solenoid valve (11c); a water film is always formed at the inner wall of the toilet bowl (b), the bowl is cleaned without any remaining urine component and no odor will be produced. That is, even if the user moves away from a front part of the toilet bowl (b) upon completion of use of the bowl and input of the sensing signal from the sensing part (12) to the control part (13) is stopped, the cleaning water supplied under the opening of the solenoid valve (11c) before its stoppage cleans the interior of the toilet bowl (b). FIGS. 19 and 20 illustrate another preferred embodiment of the toilet bowl (b), wherein the fixing frames (14) are integrally assembled and formed at the rear part of the toilet bowl (b), the functioning part of the water supplying part (11) and the control part (13) are fixed and arranged in fixing frames (14), and cover panels (15) are fixed between the fixing frames (14) so as to cover the functioning part of the water supplying part (11) and the control part (13) to make a unified assembly. The fixing frames (14) are assembled to form a box-like shape slightly higher than the height of the toilet bowl (b) and a code (13a) pulled out of the control part (13) can be connected to a power supply code (13b) arranged outside of the cover panel (15). The functioning part of the water supplying part (11) corresponds to a water supplying part (11b) and a solenoid valve (11c), a base end of the water supplying pipe (11b) is passed through the cover panel (15) projected outwardly, and can be connected to a main water supplying pipe (11h) through a connector (11g). The base end of the drain pipe (11f) connected to the toilet bowl (b) is passed through the cover panel (15) in the same manner as that of the water supplying pipe (11b), projects outwardly, and can be connected through a main drain pipe (11j). Therefore, the system shown in FIGS. 19 and 20 is completed in its work on site merely by connecting the power supply code (13a), main water supplying pipe (11h) and the main drain pipe (11j), and this system may eliminate troublesome work, such as separate mounting of the functioning part of the water supplying part (11) and the control part (13) and then the necessary connection of these elements, as found in FIGS. 13 to 15, resulting in installation work becoming simple and convenient. A hand washing bowl will now be described. The hand washing bowl (c) is supported by a mounting block (c') placed out of the unit room (A), with only its front opening part (c1) and a front wall (c2) around the opening being adjacent to the interior of the unit room (A) from the rear wall (A 8 ). The hand washing bowl (c) is provided with a hand washing water injection device (21) comprising a water supplying part, a bowl cleaning device (22), a hot air heater (23) for drying hands, an air bleeding device (24) in the bowl (c), and a control part (26) for controlling an operation of each of these devices by receiving a sensed signal from a sensing part (25) for sensing presense the hands when the hands are washed. Each of the devices and the control part (26) are arranged within the hand cleaning bowl (c) or out of the unit room (A) so as not to prevent the flow of clain air in the unit room (A). The hand washing water injection device (21) is arranged such that the water injection nozzle (21a) is displaced from an intermediate position by a width direction outwardly on the upper wall surface (c4) of the bowl part (c3) in the hand washing bowl (c), and is fixed to face downward. The nozzle (21a) is connected to a water supplying source through the water supplying pipe (21b) having a solenoid valve (21c) therein, the solenoid valve (21c) is electrically connected to the control part (26), the solenoid valve (21c) is opened for a specified period of time under instructions from the control part (26) to supply cleaning water to the injection nozzle (21a), and the nozzle (21a) injects hand washing water into the bowl (c3). The injection nozzle (21a) is inclined at a desired angle toward a vertical line passing through an intermediate position in the width-wise direction of the hand washing bowl (c). The bowl cleaning device (22) has an annular water passage (22a) at the upper circumferential part of and the bowl (c3), the water passage (22a) is connected to the water supplying source through a water supplying pipe (22b) provided with the solenoid valve (22c). The solenoid valve (22c) is electrically connected to the control part (26), the solenoid valve (22c) is opened under instructions from the control part (26), the cleaning wter is supplied to the water passage (22a), and flows from several water flowing holes (22d) opening at the bottom wall of the water passage (22a) along the inner wall of the bowl (c3) so as to clean the interior of the bowl (c3). The cleaning water from the bowl cleaning device (22) is discharged outwardly of the hand washing bowl (c) and unit room (A) together with cleaning water from the hand washing water injection device through a drain trap (22e) and a drain pipe (22f). A hot air heater (23) is provided with a hot air injection nozzle (23a) at the upper wall surface (c4) of the bowl part (c3) at a position in its width direction which is symmetrical to the injection nozzle (21a). The nozzle (23a) is connected to and the hot air generating machine (23c) through a flexible pipe (23b), the hot air generating machine (23c) is electrically connected to the control part (26). The hot air generating machine (23c) is operated for a desired period of time under instructions from the control part (26) to send the hot air to the injection nozzle (23a) and then the hands are dried by hot air blown from the nozzle (23a). The injection nozzle (23a) is inclined at the same angle as that of the water injection nozzle (21a) towards the vertical line passing through an intermediate position along the width of the hand washing bowl (c). Therefore, putting the hands at the intermediate position along the width of the hand washing bowl (c) causes both cleaning water from the water injection nozzle (21a) and hot air from the injection nozzle (23a) to be applied to the hands without moving them. The hot air generating machine (23c) is made such that a blower fan (233c), air filter (234c) and ceramic heater (235c) are arranged in sequence from the upstream side within a casing (232c) to which a suction pipe (231c) is connected. The thermal loss is less, and clean hot air can be fed in such a way that the clean air in the unit room (A) is not polluted. The air bleeding device (24) in the bowl (c3) is placed adjacent to the rear part of the bowl (c3) to form air bleeding passage (24a), the air bleeding passage (24a) is connected to a forced air bleeding fan (24c) through an air bleeding pipe (24b), and at the same time the air bleeding fan (24c) is electrically connected to the control part (26), the forced air bleeding fan (24c) is operated for a specified period of time under instructions from the control part (26) to suck dust such as effete matter of hands which has dropped into the bowl (c3) under chafing of the hands during drying, from the air bleeding passage (24a) together with hot air, and to then discharge them. The sensing part (23) is comprised of a photoelectric sensor which is arranged at a position in the upper wall surface (c4) of the bowl held between the water injection nozzle (21a) and the blowing nozzle (23a), that is, an intermediate position in a width direction of the hand cleaning bowl (c), at and as shown in FIG. 21, an optical axis (l 1 ) of the light emitting and light receiving element is inclined downward and forward by a desired angle with respect to a vertical line. The inclination of the optical axis (l 1 ) is made in order to enable the sensing part (25) to be positioned slightly deeper from the opening (c5) of the hand washing bowl (c), in order to prevent any erroneous operation of the sensing part (25) caused by accidental cutting of the light beam emitted from the light emitting element by hands and to enable rapid sensing of hands to be performed when the hands are put into the hand washing bowl (c) through the opening (c5), in case of washing of hands. Operation of each of the devices in the hand washing bowl (c) is automatically controlled by the control part (26), which received the sensed signal from the sensing part (25). In order to perform both hand washing and drying operations for a desired period of time, it is necessary to have manual control over the operation of each of the devices, and so in the preferred embodiment of the present invention the manual control is performed by a switching operation at the operating panel (27). The operating panel (27) is arranged at the side position of the hand washing bowl (c) at the rear wall (A 8 ) of the unit room (A). The operating panel; (27) is provided with a hand washing switch (27a) and a drying switch (27b) of the push-button type, light emitting diodes (27c), (27d) indicating the input condition of the switches, as shown in FIG. 23, and it is similarly provided with a stop switch (27e) of the push button type and with light emitting diodes (27f0, (27g) for displaying either automatic control or manual control and for indicating its operation, and further it is electrically connected to the control part (26). Operation of the hand washing bowl (c) during hand washing is performed with reference to the time chart and the flow chart shown in FIGS. 24 to 27. At first, in the case of an automatic control operation, when the user puts his hands into the hand washing bowl (c), the sensing part (25) detects the hands and sends the sensed signal to the control part (26). Input of a sensing signal to the control part (26) is only the first time of the inputting operation, and the sensed signals outputted subsequently to the first input time are prohibited from being input to the control part (26). When a sensed signal is inputted to the control part (26), the solenoid valve (21c) for the hand washing water injection device (21) is opened for a desired period of time, for example, 10 seconds, under instructions from the control part (26), and the cleaning water for washing hands is injected from the water injection nozzle (21a). The solenoid valve (22c) for the bowl cleaning device (22) is opened simultaneously with the injection of the cleaning water from the water injection nozzle (21a) and then cleaning in the bowl (c) is started. Time of opening of the solenoid valve (22c) is for one second, the solenoid valve (22c) is closed after this valve opening time is elapsed and the valve is then opened again after six seconds. Such periodic opening and closing of the solenoid valve (22c) is repeated several times during a hand washing time. Valve opening and closing times of the solenoid valve (22c) are counted by a timer at the control part (26), and the solenoid valve (22c) is opened or closed for a specified period of time at the control part (26). Thus, a proper amount of cleaning water is supplied continuously into the bowl (c3) of hand washing bowl (c) until completion of hand washing action under periodic opening and closing operation of the solenoid valve (22c), and the sewage generated after hand washing action is discharged out of the hand washing bowl (c) and out of unit room (A) without remaining in the bowl (c). After the hand washing and cleaning of the bowl (c3) are carried out, the hot air generating device (23) and air bleeding device (24) simultaneously start their operation after a desired time, for example, after 5 seconds is elapsed and then the hand drying and the air bleeding of the bowl part (c3) are carried out. The reason why a delay time is effected between starting operation of the hot air heater (23) and the air bleeding device (24) and stopping operation of the hand washing water injection device (21) and the bowl cleaning device (22) is that the cleaning water or sewage remaining in the bowl part (c3) is prevented from being splashed out of the bowl part (c3) with hot air produced from the hot air heater (23), and the air bleeding device may not be badly affected by the suction of the cleaning water into the air bleeding device. The hot air heater (23) is operated such that air is heated during its passage through ceramic heater (235c) under rotation of the blower fan (233c) in the hot air generating machine (23c), and hot air is blown from the blowing nozzle (23a), struck against the hands to dry them. The ceramic heater (235c) is already started to heat when the sensed signal is inputted to the control part (26), and the hot air may instantly be fed by the blower fan (233c) when the drying operation is started. The air bleeding device (24) is operated such that the bowl part (c3) is suctioned through the air bleeding passage (24a) under rotation of the forced air bleeding fan (24c), the operating time of the fan (24c) is counted by a timer at the control part (26), the fan (24c) is operated within a specified period of time at the control part (26) and then its operation is stopped after a desired delay time, for example, 5 seconds, has elapsed after the operation of the hot air generating device (23) is stopped. The reason why this delay time is provided consists in the fact that dusts such as waste matter produced by scrubbing of hands after drying is discharged out of the bowl part (c3) without remaining therein. In cases where the automatic control is changed over to a manual control the stop pushbutton switch (27e) at the operating panel (27) is depressed, and the operation performed under an automatic control is stopped and reset to its initial condition, and thereafter either the hand washing switch (27a) or the drying switch (27b) is depressed to change-over from automatic control to manual control. Even if both the hand washing switch (27a) and the drying switch (27a ) are depressed during the automatic control operation, input is not received at the control part (26). When the hand washing switch (27a) is depressed, both hand washing water injection device (21) and bowl cleaning device (22) are simultaneously started to operate in the same manner as the automatic control so as to perform both cleaning of hands and bowl part (c3). In order to stop the water injection of cleaning water after the hand cleaning is performed for a specified period of time, either the stop switch (27a) or the drying switch (27b) is depressed. When the drying switch (27b) is depressed, the hot air heater (23) and the air bleeding device (24) are started to operate with a desired time delay in the same manner as that of the automatic control after the injection of cleaning water is stopped, and a change-over from the hand washing operation to the drying operation is performed. In turn, when the drying switch (27b) is depressed, the hands can be dried for a desired period of time under operation of the hot air heater (23) in the same manner as above. In order to stop the drying operation, either the stop switch (27e) or the hand washing switch (27a) is depressed, and when the hand washing switch (27a) is depressed, the operation is changed-over to the hand cleaning operation with a delay time in the same manner as that of the automatic control. The system shown in FIGS. 28 and 29 illustrates another preferred embodiment of the toilet bowl (b), respectively. The system shown in FIG. 28 is made such that fixing frames (28) are integrally assembled and formed from the bottom part of the hand washing bowl (c) to the upper part thereof through a rear part, and the toilet cleaning water injection device (21), bowl cleaning device (22), hot air heater (23), the functioning part of air bleeding device (24), and the control part (26), are fixed and arranged in the fixing frames (28), and at the same time a cover panel (29) is fixed over the fixing frames (28), thereby covering the functioning part of each of the devices and the control part to make a unified device. The fixing frames (28) are comprised of a mounting block (28a) and a frame (28b) formed in a longitudinal box-like shape and facing upwardly from the mounting block (28a), hand washing bowl (c) is mounted and fixed on the mounting block (28a), a front opening (c1) of the hand washing bowl (c) and a front wall (c2) around the opening project out of the cover panel (29), and at the same time a code (26a) pulled out of the control part (26) can be connected to a power supply code (26b) arranged outside of the cover panel (26b). The functioning part of the toilet cleaning water injection device (21) corresponds to the water supplying pipe (21b) and the solenoid valve (21c) except for the water injection nozzle (21a), and a base end of the water supplying pipe (21b) is passed through the cover panel (29) and projected outwardly and can be connected to the main water supplying pipe (21e) through a connector (21d). The functioning part of the bowl cleaning device (22) corresponds to the water supplying pipe (22b) and the solenoid valve (22c), and a base end of the water supplying pipe (22b) is connected to the midway part of the water supplying pipe (21b) of the toilet cleaning water injection device (21) through a branch pipe (22b); thereby cleaning water is supplied. A base end of the drain pipe (22f) to be connected to the hand washing bowl (c) is also passed through the cover panel (29) in the same manner as that of the water supplying pipe (21b), is projected outwardly and can be connected to the main drain pipe (22i) through a connector (22h). The functioning part of the hot air heater (23) corresponds to a flexible pipe (23b) and a hot air generating machine (23c) except for a blowing nozzle (23a), and the hot air generating machine (23c) is mounted and fixed on a mounting plate (32d) arranged in the fixing frames (28). The functioning part of the air bleeding device (24) comprises air bleeding pipe (24b) and a forced air bleeding fan (24c), and a base end of the air bleeding pipe (24b) is passed through the cover panel (29) and projected outwardly, and can be connected to the main air bleeding pipe (24d). Therefore, the system shown in FIG. 28 is completed in its work on site by a mere connection of a power supply code (26b), a main water supplying pipe (21e), a main drain pipe (22i) and a main air bleeding pipe (24d), and it does not require any troublesome operation in which the functioning parts of each of the devices and the control part (26) are separately mounted they must then be connected to each other as shown in FIGS. 21 and 22, resulting in mounting work becoming simple and convenient. In turn, the system shown in FIG. 29 is made such that an hot air generating machine (23c) of a hot air heater (23) and an air bleeding passage (24a) formed adjacent to the rear part of the bowl part (c3) are connected by a suction and air bleeding pipe (23e). The air fed through the suction and air bleeding pipe (23e) from within the bowl part (c3) under rotation of the blower fan (233c) of the hot air generating machine (23c) is heated while it is passed through the ceramic heater (235c), and then the hot air is blown from the blowing nozzle (23a) to dry the hands and at the same time dust, such as waste matters generated during scrubbing of both hands while a drying operation is performed, are suctioned and then removed while they are passed through the air filter (234c), and they are then circulated. Operation of the automatic control, in the case of hand washing at the hand washing bowl (c) shown in FIG. 29, is carried out with reference to the time chart and the flow chart of FIGS. 30 and 31, during performance of a manual control, and the operation is performed with reference to the time chart and the flow chart of FIGS. 32 and 33. Therefore, the system shown in FIG. 29 can be installed more easily than that of FIG. 28 due to the fact that the air bleeding device and the main air bleeding pipe are not required to have a connection on site. Further, although the present preferred embodiments show that the toilet bowls (a) and (b) and the hand washing bowl (c) are installed in the unit room (A), it is not necessarily required to install three units (a), (b) and (c) and for example, two units of toilet bowls (a) and (b) or two units of toilet bowl (b) and the hand washing bowl (c) may be installed.

This invention relates to a sanitary facility room to be installed in a computer room or a clean room found in a manufacturing factory for a semiconductor element wherein the water supplying means is operated by a control part received a sensed signal from the sensing means by a sensing operation of the sensing means for a human body, a cleaning water is supplied to the sanitary device to form water films at the inner surface of the sanitary device and to perform an automatic cleaning of the sanitary device.

This application is a Continuation-in-Part of application Ser. No. 10/919,579, filed on Aug. 17, 2004, now pending, the contents of which are incorporated herein by reference. FIELD OF THE INVENTION This invention relates to tube apparatus such as tube sealers. More specifically, this invention relates to a method and apparatus for closing or severing a tube using a controllable force. BACKGROUND OF THE INVENTION In a wide variety of applications and industries, there is a need to seal, connect, weld or otherwise manipulate tubes. For example, there is often a need to create a seal at a location along the length of a tube or a portion thereof. Such a seal may be desired to prevent or substantially reduce the flow of gaseous or liquid fluid between adjacent portions of a tube. One example of an application in which a tube may be desired to be sealed is the sealing of tubes that contain blood or other bodily fluids. For example, blood may be drawn from a donor from flexible tubing that extends into a plastic blood collection bag. Once the bag is filled to its capacity, it may be desired to seal the tubing in order to prevent leakage and/or contamination or deterioration of the collected blood. After such collection, the blood may need to be typed and/or tested under various criteria. In order to provide a representative supply of blood for such typing and test purposes, a plurality of segments of the tubing may be sealed from one another to provide multiple sealed samples. Such samples may later be separately opened for typing and/or testing purposes. The foregoing comments apply not only to dielectric tube sealers but also to any apparatus configured to connect, weld, or otherwise manipulate tubes using radio frequency, heat, mechanical elements, or any other known means for manipulating tubes. SUMMARY OF THE INVENTION According to one aspect, this invention provides a tube apparatus configured to perform a tube operation on a tube portion. An exemplary embodiment of such a tube apparatus may include tube-contacting surfaces spaced from one another to receive the tube portion, at least one of the tube-contacting surfaces being movable with respect to another one of said tube-contacting surfaces to compress the tube portion, means for moving said at least one movable tube-contacting surface, and means for controlling a duty cycle of the moving means according to a compression profile of the moving means. According to another aspect, this invention provides a tube sealer to control a size of a seal formed in a tube portion. One exemplary embodiment of such a tube sealer may include a plurality of jaws mounted for movement with respect to each other, at least one of the jaws being coupled to an energy source to heat the tube portion, a solenoid coupled to a respective one of the jaws to move the respective one of the jaws to compress the tube portion, and a microprocessor configured to control the energy source and the solenoid, the microprocessor being programmable to select one or more periods during which heating of the tube portion is performed by the energy source and to select one or more compression periods, successive compression periods having a different duty cycle to supply power to the solenoid to adjust a compression action of the solenoid, thereby controlling the size of the seal formed in the tube portion. According to yet another aspect, this invention includes a method of controlling a tube apparatus configured to seal, weld or sever a tube portion, the tube apparatus including tube-contacting surfaces spaced from one another to receive the tube portion, at least one of said tube-contacting surfaces being movable with respect to another one of said tube-contacting surfaces to compress the tube portion, and an actuator coupled to said at least one movable tube-contacting surface. An exemplary method according to this aspect of the embodiment of the invention may include the steps of controlling a duty cycle of an actuator according to a compression profile of the actuator to compress the tube portion and to control an area of a seal formed in the tube portion and/or a thickness of the sealed tube portion. According to yet another aspect, this invention includes a method of controlling a tube sealer configured to seal a tube portion, the tube sealer having a heat source to selectively heat the tube portion and an actuator configured to compress the tube portion via at least one movable tube-contacting surface. An exemplary method according to this aspect of the invention may include the steps of selecting one mode of a plurality of selectable modes of operating the tube sealer, each of the modes having heating and compression profiles, the heating and compression profiles defining heating periods of the heat source for heating the tube portion and duty cycles of the actuator for compression of the tube portion, respectively, and during a plurality of periods defined by the selected mode, simultaneously heating and compressing the tube portion according to the heating and compression profiles of the selected mode. According to yet another aspect, this invention includes a method of controlling a tube sealer configured to seal a tube portion, the tube sealer having a heating source to selectively heat the tube portion and an actuator configured to compress the tube portion, compression by the actuator being controlled according to a duty cycle of the actuator. An exemplary method according to this aspect of the invention may include the steps of simultaneously heating and compressing the tube portion according to a mode selected by a user, each mode including a heating profile and a compression profile, the heating and compressing of the tube portion being adjusted based on a time to produce a measured compression of the tube portion. According to yet another aspect, this invention includes a computer readable medium to store program code for use in a microprocessor to control a tube sealer having an actuator for compressing a tube portion. An exemplary computer readable medium according to this aspect of an embodiment of the invention may include a program code segment for controlling a duty cycle of the actuator according to a compression profile to compress the tube portion, thereby controlling an area of a seal formed in the tube portion and or a thickness of the sealed tube portion. BRIEF DESCRIPTION OF THE DRAWING The invention will described with reference to the exemplary embodiments illustrated in the drawing, of which: FIGS. 1 a and 1 b are front and top views, respectively, of a tube portion sealed according to aspects of this invention. FIG. 2 is a cross-sectional end view of the tube portion illustrated in FIGS. 1 a and 1 b. FIG. 3 is a front perspective view of an embodiment of a tube sealer according to aspects of this invention. FIG. 4 is a top perspective view of the tube sealer shown in FIG. 3 . FIG. 5 is a side perspective view of the tube sealer shown in FIG. 3 . FIG. 6 is another top perspective view of the tube sealer shown in FIG. 3 . FIG. 7 is a rear perspective view of an interior region of the tube sealer shown in FIG. 3 . FIGS. 8 a and 8 b provide a flow diagram illustrating the use of an embodiment of a tube sealer according to aspects of this invention. FIG. 9 provides block diagram of a radio frequency amplifier according to aspects of this invention. FIG. 10 illustrates a circuit diagram for an embodiment of an exemplary radio frequency generator according to aspects of this invention. FIG. 11 illustrates a block diagram of an embodiment of a control circuit according to aspects of this invention. FIG. 12 illustrates an embodiment of a control board according to aspects of this invention. FIG. 13 provides a block diagram for an embodiment of a control unit according to aspects of this invention. FIGS. 14-17 are timing charts illustrating aspects of an exemplary control method according to aspects of this invention. FIGS. 18 a and 18 b provide a flow diagram illustrating the use of an embodiment of a tube apparatus according to aspects of this invention. DETAILED DESCRIPTION OF THE INVENTION Preferred features of exemplary embodiments of this invention will now be described with reference to the figures. It will be appreciated that the spirit and scope of the invention are not limited to the embodiments selected for illustration. Also, it should be noted that the drawings are not rendered to any particular scale or proportion. It is contemplated that any of the configurations and materials described hereafter can be modified within the scope of this invention. Generally, systems have been proposed to seal tubes using a pair of jaws, such as electrodes, for compressing tubing and applying radio frequency energy to melt the tubing and form a weld to effect a seal. Such systems typically may use a solenoid to compress the tubing as the RF radiation is applied. As the solenoid is activated a coil of the solenoid increases in temperature due to the current applied to the coil. A problem exist in these tube sealing systems that as the solenoid increases in temperature due to the current applied to the coil of the solenoid, compression force of the solenoid significantly decrease because resistance of the coil increases as temperature increases. Thus, frequent use of the tube sealing system, reduces the compression force to compress the tubing which significantly reduces the efficiency of the tube sealing system and produces an increased number of defective seals in the tubing being sealed. An improved tubing sealing apparatus is provided to reduce or substantially eliminate the compression force reduction in the solenoid when such a system is heavily (i.e., repeatedly) used. Exemplary tube sealers according to aspects of this invention can be adapted to seal tubes such as those illustrated in FIGS. 1 a , 1 b and 2 . Referring to those figures, a tube portion 2 is illustrated with two (2) seals 4 , thereby separating an interior 6 of the tube portion 2 into multiple sections or compartments. As is illustrated in FIGS. 1 a and 1 b , the tube portion 2 may have a diameter D and a wall thickness T 1 . The dimensions of the tube portion 2 can be varied depending upon the nature of the tube and the use thereof. The tube portion 2 may be a tube used to collect a sample of blood from a donor. If so, the tube portion 2 may be formed from polyvinyl chloride (PVC) or any another suitable material. The seals 4 in the tube portion 2 are formed by compressing the tube so that its walls come into contact with one another and simultaneously subjecting the tube portion 2 , in the area of a seal 4 , to energy until a seal is formed by heating and softening or melting the tube such that a weld can be formed. Referring to FIGS. 1 a , 1 b and 2 , the seals 4 formed in tube portion 2 will have a width W, a height H, and a thickness T 2 . It has been discovered that it may be desirable to modify, select, and/or control the “size” or “area” defined by one or more of the dimensions W, H, and T 2 . Generally, there is likely to be some limited flow of the material of the tube in the area of a seal during the formation of the seal. More specifically, the softening or melting of the material of the tube is likely to cause some migration of the material radially outwardly to arrive at a height H of the seal 4 that is greater than diameter D of the tube. Also, the width W of the seal 4 will result from some migration of the material of the tube along the axis of the tube. The dimensions W, H, and T 2 of each seal 4 are impacted by various parameters relating to the energy used to form the seal as well as the jaws of the sealer that directly form the seal. These parameters include the degree of compression imparted on the tube by the jaws (i.e., the minimum gap between the jaws), the duration of the compression (i.e., the time delay before the jaws are separated), and the duration over which the radio frequency energy is generated, among other parameters. It has been discovered that it may be beneficial to permit the adjustment of a tube sealer with respect to one or more of these parameters, as will be discussed later in greater detail. Referring again to FIGS. 1 a and 1 b , a “good” or “successful” weld or seal 4 across a tubing portion 2 will be likely to exist if the combination of melting of the tubing with the compressive force exerted by the jaws forming the seal force lateral flow of the plastic to develop ears or tab portions disposed on opposite sides of the tubing. Such ears or tabs may be indicative of an impermeable seal across the tubing. Generally referring to FIGS. 3-7 , one aspect of this invention provides a dielectric tube sealer 8 adapted to limit radio frequency emissions or emanations during operation. The dielectric tube sealer 8 includes an enclosure such as a cabinet 10 and first and second jaws (i.e. first and second tube-contacting surfaces) 42 and 26 , respectively, oriented with respect to the cabinet 10 to receive a tube portion in a space therebetween. The first jaw 42 is fixed and is coupled to a radio frequency generator, and the second jaw 26 is movable with respect to the first jaw 42 and is coupled to ground potential. A shield 12 is positioned adjacent the cabinet 10 and configured to at least partially enclose the first and second jaws 42 and 26 yet permit the introduction of a tube portion to a position between the first and second jaws 42 and 26 . The shield 12 thereby reduces radio frequency emanations from the first jaw 42 , and the shield 12 can be movable with respect to the cabinet 10 to at least partially expose the first and second jaws 42 and 26 . According to another aspect of the invention, a dielectric tube sealer 8 is adapted to detect successful or failed seals. The dielectric tube sealer 8 includes jaws 26 and 42 mounted for movement with respect to one another between (1) a first position spaced from one another to receive a tube portion and (2) a second position proximal one another to compress the tube portion, wherein the jaws 26 and 42 in the second position define a gap selected to form a successful seal. The dielectric tube sealer 8 also includes a sensor 204 positioned to detect when the jaws 26 and 42 have moved into the second position. The dielectric tube sealer 8 also includes a timer electrically coupled to the sensor 204 for determining the time delay before the jaws 26 and 42 have moved into the second position. A time delay up to a predetermined time limit indicates a successful seal, and a time delay exceeding the predetermined limit indicates a failed seal. According to another aspect of the invention, a dielectric tube sealer 8 includes a radio frequency generator configured to generate radio frequency for a time period. Jaws 26 and 42 are mounted for movement with respect to one another, one of the jaws 26 or 42 being coupled to the radio frequency generator. The dielectric tube sealer 8 also includes a microprocessor or microcontroller 206 configured to control the radio frequency generator. The microcontroller 206 is programmable to select the time period or time periods during which radio frequency is generated by the radio frequency generator, thereby controlling the area of the seal formed in a tube. Referring to FIGS. 3-7 , exemplary features of one embodiment of a tube sealer according to this invention will now be described. The dielectric tube sealer 8 includes a cabinet 10 to which a cover or shield 12 is removably mounted. The dielectric tube sealer 8 also includes a power switch 14 which acts as an on/off switch for the operation of the unit. The dielectric tube sealer 8 further includes a power indicator 16 and a seal indicator 18 , both of which may take the form of an LED according to one exemplary embodiment of the invention. The seal indicator 18 will be on when the solenoid is energized. When the shield 12 is off and the unit is inoperable, the seal indicator 18 will flash (except when the unit is in programming mode as will be described later). Referring specifically to FIG. 4 , which reveals internal features of the dielectric tube sealer 8 , an actuator (e.g., solenoid 20 ) is mounted on a mounting platform 22 within an interior of the cabinet 10 . It will be noted that, although cabinet 10 is adapted as a table-top unit, cabinet 10 may also be reconfigured as a hand-held device that is remote from other components that are illustrated within the cabinet 10 in FIGS. 3-7 . Coupled to the solenoid 20 is a ground jaw shaft 24 on which the ground jaw 26 is positioned. A flag 28 is provided as a part of the assembly of the ground jaw shaft 24 in order to actuate a stop sensor 204 , which will be described in further detail later. A fastener 30 , which may take the form of a cap-head screw or any other suitable fastener, is used to make a connection between a wire 32 leading to a radio frequency board ( FIG. 10 ) and the RF jaw 42 (see RF jaw 42 in FIG. 5 , for example). A start lever 33 is also provided as a component of the dielectric tube sealer 8 . The start lever 33 has a proximal end 34 and a distal end 36 , wherein the proximal end 34 extends outwardly from the cabinet 10 and the distal end 36 extends inwardly into the interior of cabinet 10 . The proximal end 34 of the start lever 33 is depressed downwardly when a tube is introduced into a position between the ground jaw 26 and the RF jaw 42 , and the distal end 36 of the start lever 33 is pivoted upwardly. A flag (not shown) toward the distal end 36 of start lever 33 actuates a start sensor 205 ( FIG. 11 ), details of which will be provided later. The start lever 33 , ground jaw shaft 24 , and connection to the RF jaw 42 each passes through an insulator 40 . According to exemplary aspects of the invention, the insulator 40 is in the form of a block of insulating material. The insulating material may be DELRIN, for example, or any other suitable insulator. If DELRIN is used, it is preferably black to provide a UV protectant. The insulator 40 serves two (2) purposes according to exemplary features of this invention; namely, it isolates the radio frequency potential applied to the RF jaw from the ground potential of the ground jaw and it provides a low-friction surface through which moving parts (e.g., ground jaw shaft 24 ) can slide. Referring to FIG. 5 , it will be seen that a portion of the RF jaw 42 extends outwardly beyond the surface of the insulator 40 , thereby exposing a surface of the RF jaw 42 for contact with a tube portion to be sealed. Also shown in FIG. 5 is a power supply 44 , which is positioned under the mounting platform 22 . Although not shown in FIG. 5 , it has been discovered that there is benefit in selecting a power supply 44 that incorporates a fan for heat dissipation. Heat will of course be generated within the cabinet 10 by virtue of the operation of the solenoid 20 and other components of the system. It has been discovered that the positioning of a power supply 44 toward the base of the cabinet 10 can help dissipate significant heat when the power supply 44 is provided with the fan. More specifically, the fan of the power supply 44 exhausts heat downwardly and outwardly through a base portion of the cabinet 10 . Referring still to FIG. 5 , the RF jaw remains fixed with respect to the cabinet 10 and the ground jaw 26 moves with respect to the RF jaw 42 by virtue of sliding movement of ground jaw shaft 24 through an aperture in the insulator 40 and the action of the solenoid 20 . More specifically, upon actuation of the dielectric tube sealer 8 to seal a portion of a tube, the solenoid 20 will withdraw the ground jaw shaft 24 toward the interior of the cabinet 10 , thereby moving the ground jaw 26 closer the RF jaw 42 . In that manner, the jaws 26 and 42 have two (2) positions; namely, an open position in which the jaws 26 and 42 are separated from one another a distance sufficient to receive a tube, and a closed position in which the jaws 26 and 42 are proximal to one another such that a tube positioned therebetween will be in a compressed state. The gap between the jaws 26 and 42 when the jaws are in the closed position is selected to correspond substantially to the desired thickness T 2 of the seal 4 (see FIG. 2 ). That gap can be periodically adjusted during calibration of the dielectric tube sealer 8 to ensure that an appropriate thickness T 2 is imparted to a seal. Also, the gap can be adjusted to avoid arcing between the jaws, which would otherwise occur if the jaws were too close together. On the other hand, if the jaws are too far apart, the seal of the tube might not be properly formed and might leak. When the jaws 26 and 42 are in the closed position (not shown), the flag 28 on the opposite end of the ground jaw shaft 24 will block an optical sensor such as stop sensor 204 to signal that the seal is virtually complete. Accordingly, the flag 28 is sized and positioned to actuate such a sensor as the jaws 26 and 42 enter the closed position. For example, when the gap between jaws 26 and 42 is reduced to a predetermined size (e.g., 0.1 mm-0.2 mm), the flag 28 will trigger the sensor to indicate full compression of the tubing. Although not shown in FIGS. 3-7 , a controller board, such as the exemplary embodiment of a board shown in FIG. 12 , is mounted in a horizontal position extending rearwardly from the top of the insulator block 40 . Standard fasteners can be used to fasten the board to the insulator block 40 or to otherwise mount the board within the cabinet 10 . The sensors for sensing the flags on the start lever 33 and the ground jaw shaft 24 are mounted to the controller board and are positioned on the board in locations selected to correspond to the respective flags on the start lever 33 and ground jaw shaft 24 . Referring now to FIG. 6 , it will be seen that the RF jaw 42 is provided with a substantially flat surface 43 for contact with a tube portion to be sealed. Similarly, the ground jaw 26 is also provided with a substantially flat surface 27 for contact with the opposite side of the tube portion. These flat surfaces 27 and 43 are sized and oriented so as to impart a predetermined configuration to a seal 4 in a tube portion 2 . It will be appreciated that the widths and other dimensions of the flat surfaces 27 and 43 can be modified so as to alter the configuration of the seal 4 . More specifically, the surfaces 27 and 43 can be modified to impart functional or ornamental features to the surface of the seal, depending upon the particular application or preferences of the end user. Also, the texture or finish of the surfaces 43 and 27 can be modified to impart a particular surface feature to the seal. As shown in the figures, the ground jaw shaft 24 is substantially rounded in cross-sectional shape. For example, a cylindrical shape for ground jaw shaft 24 can be selected to correspond to a through-hole formed in the insulator 40 . Also, a cylindrical shaft or otherwise rounded shaft may be easier to clean in the instance of leaked fluids because the cylindrical shape will not encourage an accumulation of fluids on the ground jaw shaft 24 . The portion of ground jaw shaft 24 on which the ground jaw 26 is formed is also substantially cylindrical except for the flat surface 27 formed thereon. As is best illustrated in FIG. 5 , it will be seen that the axis of the longitudinally extending portion of the ground jaw shaft 24 is spaced from, but substantially parallel to, the axis of the solenoid 20 . Also, the axis of the solenoid 20 corresponds to the position on the RF jaw 42 and ground jaw 26 that contact a tube portion to be sealed. In order to provide this feature, the ground jaw shaft 24 (extending all the way from the flag 28 extending upwardly beyond the axis of the solenoid to the top of the ground jaw 26 ) forms a substantially “U” shaped configuration. Such a configuration makes it possible to compress a tube portion along an axis of compression that is common to the axis of the solenoid 20 . The ground and RF jaws are, according to one exemplary embodiment, formed from a metal but can optionally be formed from any conductive material. The jaws can be formed from steel plate or rod by known forming techniques. It has been discovered that the configuration of the RF jaw as a fixed jaw at least partially insulated and located adjacent the cabinet 10 helps to reduce the radio frequency emanations from the dielectric tube sealer 8 . More specifically, the mounting of the RF jaw at least partially within an insulator block such as insulator 40 helps to shield the emanations of radio frequency energy. This can be accomplished by configuring the ground jaw 26 to be the moving jaw that extends outwardly from the cabinet 10 . By exposing the ground jaw 26 as the outer jaw, as opposed to the RF jaw 42 , the radio frequency emanations from the dielectric tube sealer 8 are further reduced. The configuration of the ground jaw shaft 42 as an exemplary “U” shaped configuration permits the orientation of the stationery RF jaw 42 in or near the cabinet with the ground jaw 26 extending outwardly beyond the RF jaw 42 . Referring now to FIG. 7 , a magnet 46 is mounted to a portion of the shield 12 . Although not shown in FIG. 7 , HALL effect sensor “H 1 ” on the control board shown on FIG. 12 corresponds in position to the magnet 46 when the shield 12 is in place and the control board is mounted within the cabinet 10 . By virtue of the HALL effect sensor, therefore, the presence or absence of the magnet 46 (and therefore the presence or absence of the cover or shield 12 ) can be detected. It has been discovered that combined features of the exemplary dielectric tube sealer 8 cooperate to reduce emanations of radio frequency energy during operation of the sealer. Although each of the foregoing features helps to reduce radio frequency emanations, the combination of the shield 12 , the at least partial insulation of the stationery RF jaw 42 , and the outward positioning of the movable ground jaw 26 provide significant reductions in RF emanations. Also, the configuration of the jaws and the insulator with respect to one another helps to prevent arcing between the jaws (e.g., arcing between ground and RF potentials). More specifically, the extension of jaw 42 outwardly from the insulator 40 helps to prevent bridging of fluids such as blood between the RF jaw 42 and the ground jaw shaft 24 . In the exemplary embodiment illustrated in the figures, the shield 12 is removably mounted adjacent the cabinet 10 . Removal of the shield 12 facilitates cleaning and maintenance of the jaws and other components of the tube sealer 8 . As will be described later in greater detail, the removal of the shield 12 also facilitates the periodic calibration of the tube sealer to maintain an appropriate seal thickness and facilitates the programming of the tube sealer. While the exemplary shield 12 is removable and replaceable by virtue of a sliding engagement with the insulating block 40 , the tube sealer is configured to prevent its operation while the shield 12 is not in place. Contact between the shield 12 and the cabinet (e.g., by virtue of the flanges of the shield 12 extending between the insulator 40 and the cabinet 10 ) is optionally provided to ground the shield 12 . The shield 12 may be formed from a conductive material such as a metal. The slot (not numbered) in the shield 12 permits a user to insert a portion of the tube to be sealed between the jaws of the dielectric tube sealer 8 . The shape and configuration of the slot and the body of the shield are not important, however. Referring now to FIGS. 8 a and 8 b , a flow diagram illustrating operation of an exemplary embodiment of a tube sealer according to this invention will now be described. Steps 50 - 63 roughly correspond to an exemplary sealing operation of the unit, steps 64 - 67 illustrate exemplary operation of the system in connection with a failed seal, steps 68 - 73 illustrate an exemplary programming mode, and steps 74 and 75 illustrate an exemplary inoperable mode. Referring first to the exemplary sealing operation illustrated in steps 50 - 63 in FIGS. 8 a and 8 b , the unit is turned on in step 50 , which is followed by a query in step 51 as to whether the cover or shield 12 is in place. This query can be answered, for example, by use of a Hall sensor to detect the presence or absence of a magnet 46 on the shield 12 . In step 52 , the mode setting is read from the memory of the sealing unit, and the power LED is flashed in step 53 to indicate the mode selected. The number of flashed of the LED can indicate the mode. The mode may correspond, for example, to the time delay mode selected in steps 68 - 73 (described later). After the mode selected is indicated, the power LED is turned on in step 54 . In step 55 , a query asks whether the start switch has been activated. This query can be answered, for example, with the use of an optical sensor such as the start sensor 205 to detect the presence or absence of a flag on a distal end 36 of the start lever 33 , which would indicate that a tube portion has been inserted between the jaws of the sealer, thereby depressing the proximal end 34 of the start lever 33 . If the start switch has been activated, the solenoid and RF generator (and red seal LED) are turned on in step 56 . Step 57 queries whether the limit switch is activated, which can be answered, for example, depending on whether the flag 28 on the ground jaw shaft 24 is sensed by the optical sensor or stop sensor 204 on the control board. If so, the programmed time delay is read in step 58 and the RF generator is turned off after the programmed time delay elapses in step 59 . After a predetermined time (e.g., 500 ms), which may be selected based on the amount of time desired for the seal to cool adequately, the solenoid (and red seal LED) is turned off in step 60 , and a count is added to the memory for an updated count of complete seals in step 61 . The successful seal is then completed in step 62 and the unit can then be readied to create another seal at step 63 . If at any time during power “on” of the sealer the sealer cover 12 is removed, then the seal LED remains flashing and the unit will not respond to the start sensor 205 . Referring now to the exemplary failed seal mode in steps 64 - 67 , a query is made in step 64 to determine whether 3 seconds, or some other predetermined delay, has elapsed since the solenoid and RF generator were turned on in step 56 . If so, that means that too much time has elapsed since the start of the sealing process without a full seal being indicated by the limit switch. In other words, thereby indicating that the seal has not yet been made. If so, the RF generator and solenoid power are shut off in step 65 , and the seal LED flashes 3 times to indicate to the user of the sealer that the seal was unsuccessful in step 66 . If a buzzer is incorporated into the sealer system as an audible indicator to the user and the buzzer is programmed to activate, then the buzzer is sounded in step 66 . In step 67 , a count is added to the memory to updated the count of incomplete seals and the sealer is readied for another attempt at steps 62 and 63 . Referring now to the exemplary programming mode in steps 68 - 73 , if the cover is off (step 51 ) and the limit switch or stop sensor 204 is activated (step 68 ) during system start up, then the sealer unit scrolls through a menu of available delay times in step 69 . Accordingly, the programming mode in steps 68 - 73 is initiated by: (1) either removing the cover 12 , using start lever 33 to activate the limit switch or, otherwise, pushing the ground jaw 26 in to activate the limit switch, (2) turning the unit on, and (3) selecting a delay time. In step 70 , the power LED can flash as an indicator of a variety of selectable delay times and/or an audible alarm mode. In one embodiment, six (6) modes are available for selection. Program mode is initiated when the shield 12 is off, the limit switch is activated, and the power is then turned on. If the cover or shield is removed after power up and the limit switch is triggered, the unit will not enter program mode. For example, one flash may correspond to a particular mode with a delay time. As mentioned, the user of the system can activate the limit switch (step 68 ) by either using start lever 33 or, otherwise, pushing in the ground jaw shaft 24 or ground jaw 26 while the cover is off. While in the programming mode, the system will continue to scroll through the menu of possible delay times until the limit is switch is deactivated at step 71 . In other words, if the limit switch remains activated (e.g., by the user retaining the ground jaw shaft 24 in a closed position) then the system will continue to scroll delay times. Upon release of the ground jaw shaft 24 by the user, the limit switch will thereby be deactivated in step 71 and the delay mode selected by the user by deactivating the limit switch is then stored in the memory in step 72 . The various programmed modes may determine the delay times and/or the nature of the indicator with respect to failed and successful seals. For example, a menu of program modes can include modes configured to sound an audible alarm (e.g., a buzzer) in the event of a failed seal. Alternatively, modes can dictate a silent, visual alarm depending on the preferences of the end user. In one exemplary embodiment, six (6) modes are provided to offer three delay times with an audible indicator and three delay times without the audible indicator. The delay times can be, for example, 50 ms, 100 ms, and 150 ms, but a variety of delay times can be provided depending on the material to be sealed, the size of the tubing, the application for the tube sealer, and other factors. As indicated in step 72 , the delay mode selected by the user will correlate to a desired seal width. Generally, the longer the delay time (i.e., prior to turning off the RF generator), then the wider the seal may be. After step 72 , the programming mode is concluded at step 73 . Referring now to an exemplary inoperable mode of the dielectric tube sealer 8 in steps 74 and 75 , if the cover is off (step 51 ) and the limit switch is not activated (step 68 ), then the unit should not be operated by a user and a warning is delivered to the user in the form of the flashing of the seal LED in step 74 . As indicated in step 75 , further seal operation is prevented, and the system is returned to the query of whether or not the cover is on (step 51 ). Referring next to FIG. 9 , there is shown an exemplary block diagram of a radio frequency (RF) energy generator, generally designated as 100 , for providing RF power to melt and weld a seal across a plastic tube. As shown, RF energy generator 100 includes RF amplifier 101 , coupling coil 107 and jaw/electrode 108 . RF amplifier 101 may include crystal oscillator 102 , monolithic amplifier 103 , current driver 104 , push/pull amplifier 105 , and filter network 106 . These are discussed below. An exemplary electrical circuit of RF amplifier 101 is shown in FIG. 10 , and may include electrical components that are surface mountable on a single board. Referring to both FIGS. 9 and 10 , there is shown crystal oscillator 102 capable of providing an RF signal at 40.68 MHz. The RF signal provided by crystal oscillator 102 may be filtered by a network of components (R 2 , C 1 , C 2 , C 3 and L 1 ) prior to amplification by monolithic amplifier 103 . The monolithic amplifier, designated as U 1 in FIG. 10 , may be a MAV11 monolithic amplifier for providing an amplified RF output that may be adjustable by way of resistive components R 4 , R 5 and R 15 . The RF energy is adjustable largely by potentiometer R 5 . Alternatively, resistive components R 4 and R 5 can be removed, allowing the amplifier to run at maximum power, which will be controlled by fixed resistor R 3 . The crystal oscillator and monolithic amplifier may be turned on/off by way of switching transistors Q 6 and Q 2 . Upon activation by RF trigger input signal (provided from a control circuit, discussed below), transistors Q 6 and Q 2 may be turned on, thereby allowing voltage, +V, to saturate transistor Q 1 and start RF oscillation. Switching transistors Q 6 and Q 2 will activate monolithic amplifier U 1 to amplify the RF oscillation. The output energy from monolithic amplifier 103 may be filtered by various components including C 5 , C 7 , C 8 , L 2 and L 3 . The filtering advantageously prevents RF energy from feeding into the power supply and noise from reaching a microcontroller residing on the control circuit (discussed below). The output energy from monolithic amplifier 103 is further amplified by current driver 104 and push/pull amplifier 105 . Current driver 104 may include power amplifier Q 3 for driving step-down transformer L 4 (5T to 1T), which effectively lowers the output voltage and increases the current by a five-to-one ratio. The output of step-down transformer L 4 may be provided to push/pull amplifier 105 . In the exemplary embodiment of FIG. 10 , the push/pull amplifier may have a configuration that includes transistors Q 4 and Q 5 for driving step-up transformer L 5 (1T to 3T). The amplified RF output signal from push/pull amplifier 105 may be low pass filtered by filter network 106 and may include components L 6 , L 7 , L 8 , C 13 , C 14 , C 15 , C 16 and C 17 . It will be appreciated that filter network 106 may provide a cut-off frequency for RF harmonics above the baseband frequency of crystal oscillator 102 . Completing description of RF amplifier 101 , additional filtering components may be included on the surface mountable RF board, such as D 1 , L 9 , C 11 , C 12 and C 18 . These additional filtering components may further prevent RF noise from reaching the power supply (+V, for example) and the microcontroller on the control circuit. In the embodiment shown, the amplified RF output signal is sent to coupling coil 107 , which may be mounted separately from RF amplifier 101 . Coupling coil 107 may be included to provide a matching impedance (50 ohms) between filter network 106 and jaw electrode 108 . In this manner, sufficient RF energy may be radiated from jaw electrode 108 to provide efficient melting and welding of the plastic tubing. In the RF circuit of FIG. 10 , monolithic amplifier U 1 , may be configured to provide approximately 8-9 dB of amplification. Coupled between oscillator 102 and current amplifier Q 3 , the monolithic amplifier amplifies the low output signal from oscillator 102 and may achieve a maximum output power of 0.5 watts, for example. Sufficient gain is provided from the monolithic amplifier to directly drive current amplifier Q 3 . It will be appreciated that the monolithic amplifier is optionally utilized to provide gain in a single stage that conventionally may require three or more stages of amplification. The monolithic amplifier also requires less filtering. As a result, the RF circuit may be compact and small in size. The monolithic amplifier may, for example, be an MAV-11 amplifier manufactured by Mini-Circuits in Brooklyn, N.Y. Referring to FIG. 11 , an exemplary embodiment of a control circuit, generally designated as 200 , will now be described. Control circuit 200 is adapted for monitoring and controlling the tube sealing operation. The control circuit may also provide status and alerts to the operator (or user). As shown, the heart of the control circuit is microcontroller 206 , and, for example, may be AVR microcontroller ATtiny 28L. In the embodiment shown, microcontroller 206 monitors sealer cover sensor 203 , stop sensor 204 and start sensor 205 . In response to these sensors and in response to a programmed method of operation, microcontroller 206 activates buzzer 214 , power on LED (green) 215 , seal indicator LED (red) 216 , solenoid 217 and RF trigger output to the RF amplifier board. Each of these elements may be activated by way of respective drivers 209 - 213 . Of course, a driver may be omitted, if the microcontroller is capable of directly driving the element. As shown, microcontroller 206 is coupled to memory 207 , which may be an EEPROM, such as FM 25160, and is capable of providing over a billion write operations. One such write operation may include microcontroller 206 storing “good/bad seal” status into memory 207 . Another write operation may include storing the modes of operation. Also included may be data port 208 for allowing the user to access memory 207 and obtain status information of a sealing operation. Control circuit 200 may also include voltage regulator 201 and reset monitor 202 . As shown, voltage regulator 201 regulates the V+voltage (for example 13.8 V) and provides Vcc voltage to both the microcontroller and the memory. Reset monitor 202 may also be included to continuously monitor the Vcc voltage from regulator 201 . If the voltage drops below a threshold (for example 4.68 V), microcontroller 206 may be reset by monitor 202 . Describing next the sensor signals provided to the microcontroller, there is shown sealer cover sensor 203 , which may be a Hall sensor adapted to sense magnetic fields emanating from a pole magnet 46 disposed on the cover or shield 12 . It will be appreciated that the placement of the Hall sensor may be such that if the magnetic fields are absent (or below a threshold), the Hall sensor may effectively alert the microcontroller that the sealer cover is not in a shielding position. In response to the Hall sensor alert, the microcontroller may be programmed to prevent activating the solenoid and the RF trigger signal. Start sensor 205 may include a combination of a transistor and a photodiode for sensing that the tube is in proper position for sealing. It will be appreciated that the microcontroller may be programmed to prevent activation of the solenoid and the RF energy until the tube is in proper position. In the example shown, start sensor 205 senses an absence of light that results from depression of a lever 33 after the tube has been placed in position. Depression of the lever 33 , in turn, raises a flag that blocks the light from reaching the photodiode. Blockage of the light may turn off the transistor and cause activation of a signal to inform the microcontroller that the tube is in position. In a similar manner, stop sensor 204 may include a similar combination of transistor and photodiode for sensing that a limit switch is to be activated. Activation of the limit switch may indicate that a preset jaw-gap has been reached (or a predetermined thickness of the seal has been reached). Activation of the limit switch may result from movement of a flag such as flag 28 of ground jaw shaft 24 into position to block light from reaching the photodiode of stop sensor 204 . Upon turning off the photodiode, the transistor may also be turned off, thereby providing an output signal to inform the microcontroller of the limit switch having been activated. Turning next to output signals that may be provided by microcontroller 206 , there is shown buzzer 214 that may be activated to alert the user that a step in the method is not successfully completed. For example, if sealing is not successfully completed, the buzzer may be activated. In another embodiment of the invention, the buzzer may be omitted. Power-on LED (green) 215 may be activated by the microcontroller to alert the user that the sealing unit is turned-on. The power-on LED may also be controlled from the microcontroller to flash on-and-off. The microcontroller may be programmed to cause the LED to flash a predetermined number of times to indicate a mode of operation (there may be, for example, six modes of operation corresponding to delay times, as discussed previously). Seal indicator LED (red) 216 may be activated by the microcontroller to alert the user that the RF energy and the solenoid is activated. The microcontroller may also be programmed to cause the seal indicator LED to flash, for example, if power to the unit is on and the shield cover 12 is not in position. In addition, the seal indicator LED may be programmed to flash a predetermined number of times to indicate, for example, that the RF energy and solenoid power are off. Completing the description of control circuit 200 , microcontroller 206 may be programmed to energize solenoid 217 (item 20 in FIG. 5 ). The solenoid may be, for example, a 12 V solenoid energized by way of driver 212 . The driver may be a transistor-switch that when activated by the microcontroller places a ground potential at one end of the solenoid (the other end already having a 12 V potential). Microcontroller 206 may be programmed to generate the RF trigger signal for turning on the RF amplifier. Although shown as having driver 213 in the path between the microcontroller and switching transistor Q 6 ( FIG. 10 ), it will be appreciated that the AVR microcontroller ATtiny 28L may drive the transistor without need for a driver. Exemplary physical spacing among the components shown schematically in FIG. 11 are provided in FIG. 12 . The controller board may be positioned within the cabinet or other form of enclosure in such a way that the flags of the start lever and ground jaw correspond to the positions of the optical sensors and such that the position of the Hall sensor corresponds to the shield's magnet. A notch is provided in the insulator 40 at a location corresponding to the magnet 46 of the cover 12 to accommodate the Hall sensor. A connector (such as connector J 1 shown in FIG. 12 ) can be provided for connection between the dielectric tube sealer 8 and an external computer or monitor. For example, a computer can be connected to the dielectric tube sealer 8 by means of the connector to download or upload information. In one exemplary embodiment, a Personal Digital Assistant (PDA) or other computer, communications, or reading device can be connected to download the counts of failed and successful seals. This count information can be used to monitor the amount of the use of the sealer, to schedule maintenance and calibration of the sealer, etc. Also, the recordation of the count helps to track the number of cycles a unit has completed, diagnose problems with the equipment, determine maintenance needs, and make accountings for billing purposes. Referring back to FIG. 11 , microcontroller 206 may be programmed to output a pulse width modulated (PWM) signal to supply PWM power to solenoid 217 . That is, the PWM signal from microcontroller 206 may control a duty cycle of the power supplied to solenoid 217 . Solenoid 217 may be, for example, a 12 V or 13 V solenoid and may have a power rating in the range of 30-80 watts, preferably 60 to 70 watts, and a coil of solenoid 217 may have a DC resistance in the range of about 2.0-5.0 Ω. Moreover, the PWM signal may be at a frequency in the range of between about 250 Hz to 5 KHz. In a typical tube apparatus that does not include such a pulse width modulation operation, the solenoid heats up during continuous usage and the DC resistance increases at a result of such heating resulting in a reduction in current supplied to the solenoid and a corresponding reduction in compression force exerted by the jaws of the typical tube apparatus. Also the coil transfers heat to the plunger which would conduct unwanted heat to the movable ground jaw 26 . By controlling the duty cycle of the PWM power supplied to solenoid 217 , heating of solenoid 217 may be controlled (i.e., reduced or substantially eliminated) and instantaneous compression force produced during on cycles may remain substantially constant throughout all tubing operation of the tubing apparatus. Microcontroller 206 outputs the PWM signal to driver 212 . Driver 212 is connected with a DC voltage supply, for example, at Vcc voltage, such that the DC voltage supply switchably energizes solenoid 217 according to the PWM signal from microcontroller 206 . That is, driver 212 may be, for example, a switch switchably coupling the DC voltage supply to solenoid 217 such that microcontroller 206 may control the switch (driver 212 ) according to the PWM signal output from microcontroller 206 . FIG. 13 illustrates an alternative embodiment for duty cycle control of solenoid 217 . Referring to FIG. 13 , a pulse width modulation (PWM) controller 300 maybe included in the tube apparatus. PWM controller 300 includes an input terminal 301 and an output terminal 302 . Input terminal 301 may be connected to any mode input device 303 . Mode input device 303 may provide, for example, an analog voltage proportional to the desired duty cycle. That is, for example, if a 10V signal from mode input device 303 represented a 100% duty cycle, then a 5V signal would represent a 50% duty cycle and soon on. Thus, mode input device 303 may be programmed with the selectable modes, and the selected mode selected by the user may be communicated directly to PWM controller 300 without affecting microcontroller 206 . In such a configuration, driver 212 would be coupled to output terminal 302 of PWM controller 300 , instead of microcontroller 206 . Driver 212 and solenoid 217 have the same functionality previously described. Moreover, a separate mode indicator 304 may be provided, such as an LED indicator, a display device or, otherwise, a wireless connectable device, such as a PDA (i.e., palm pilot) may be used to indicate the selectable modes and the selected mode. FIG. 14-17 illustrate an exemplary embodiment of four (4) pulse width modulated signals defining four different compression profiles and corresponding delay times defining corresponding heating profiles that are selectable modes by a user. These selectable modes are store in memory and are adjustable according to actual measured compression of the tube portion. A compression profile refers to establishing one or more periods, each having a successively different duty cycle such that the composite force (i.e., average force for that period) provided by solenoid 217 varies during the one or more periods. A heating profile refers to establishing one or more periods during which heating (e.g., by radio frequency source) of the tube portion occurs. Referring to FIGS. 14-17 , the output of microcontroller 206 is represented by a control signal 120 , 125 , 130 or 135 . Control signals 120 , 125 , 130 or 135 corresponding to the duty cycle of solenoid 217 for four (4) different selectable modes (i.e., first through fourth modes). Each control signal 120 , 125 , 130 or 135 may be a pulse width modulated signal. That is, microcontroller 206 generates a control signal 120 , 125 , 130 or 135 according to a compression profile, to control the duty cycle of power supplied to solenoid 217 to actuate solenoid 217 and the coupled movable ground jaw 26 , thereby compressing the tube portion. Microcontroller 206 controls the duty cycle of power supplied to solenoid 217 for moving ground jaw 26 to adjust the area of the seal formed in the tube portion during compression and/or thickness T 2 of the sealed area. That is, by varying the composite force during the compression operation the area of the seal formed by the compression operation and/or the thickness T 2 of the sealed tube portion may be adjusted to produce improved seals. Moreover, the RF generator 100 may generate heat in the tube portion according to the heating profile simultaneously with the compressing of the tube portion to adjust the area of the seal tube portion and/or the thickness T 2 of the sealed tube portion. In an initial period TP 1 , a initial duty cycle of the control signal 120 , 125 , 130 or 135 is 100%. That is, solenoid 217 is fully turned on. The initial period TP 1 is for a time period that varies according to the mode selected and is in a range of about 70 to 200 milliseconds. After, initial period TP 1 is complete, a heating period TP 2 is commenced. The duration of the heating period TP 2 is based on activation of the limit switch (i.e., the duration of the heating period TP 2 is determined based on a time to produce a measured compression of the tube portion). The duration of the heating period T 2 is an indicator of a good tubing operation being accomplished by the tube apparatus. In the heating period TP 2 , the tube portion is simultaneously heated by RF generator 100 and compressed via solenoid 217 . After, the heating period TP 2 is complete, a sealing period TP 3 is commenced. The duration of the sealing period TP 3 varies according to the mode selected and may be in the range of about 0 to 200 milliseconds. In the sealing period TP 3 , the tube portion is simultaneously heated by the RF generator 100 and compressed via solenoid 217 , however, generally, composite compression force (i.e., the average force over the particular period, TP 3 in this case) is lower in the sealing period TP 3 than in the heating period TP 2 . That is, the duty cycle of solenoid 217 in the sealing period TP 3 is typically less than the duty cycle of solenoid in the heating period TP 2 . After the sealing period TP 3 is complete, a cooling period TP 4 is commenced. The duration of the cooling period TP 4 varies according to the mode selected and may be in the range of about 0 to 500 milliseconds. In the cooling period TP 4 , RF generator 100 is stopped and the composite compression force may remain the same as in the sealing period TP 3 (i.e., the duty cycle of solenoid 217 remains the same in the heating and cooling periods TP 3 and TP 4 ). After, the cooling period TP 4 is complete, power to solenoid 217 is stopped (see period TP 5 ). Microcontroller 206 may simultaneously control both the heating profile (e.g., a radio frequency energy profile) for heating of the tube portion and the compression profile for compressing of the tube portion to adjust the area or the thickness T 2 of the sealed tube portion. During the initial, heating and sealing periods TP 1 , TP 2 and TP 3 , simultaneously heating and compressing of the tube portion occurs and during the cooling period TP 4 , only compressing of the tube portion occurs. Although it is provided that the duration of the heating period TP 2 is based on a measure compression of the tube portion by activating the limit switch, it is contemplated that the measurement of compression may be provided by measuring impedance changes across ground and RF jaws 26 and 42 . Although an initial period TP 1 is shown, it is contemplated that for particular types of tube portions (for example, very thin walled tube portions) that the initial period TP 1 may be eliminated. For the four (4) exemplary selectable modes (i.e. first through fourth modes), in heating period TP 2 , the duty cycle of solenoid 217 may be 10%, 50%, 70% and 80%, respectively. For the first to fourth selectable modes, in sealing and cooling periods TP 3 and TP 4 , the duty cycle of solenoid 217 may be 40%, 40%, 48% and 64%, respectively. By providing different selectable modes, the user can select a mode to provide, for example, a particular width W and/or thickness T 2 of the sealed tube portion. That is, for a particular tube portion by selecting, for example, the fourth mode a wider sealed tube portion may be realized than, otherwise, if the first mode is selected. Although in the exemplary selectable modes specific values are provided for duty cycles in the various periods (i.e., the initial period TP 1 , the heating period TP 2 , the sealing period TP 3 and the cooling period TP 4 ), other duty cycles are possible as long as a good seal can be produced. The preferred ranges for duty cycles in the various periods are as follows: (1) in initial period TP 1 , the duty cycle of solenoid 217 is desirably in the range of about 90% to 100%; (2) in heating period TP 2 , the duty cycle of solenoid 217 is desirably in the range of about 10% to 90%; and (3) in third and fourth periods TP 3 and TP 4 , the duty cycle of solenoid 217 is desirably in the range of about 40% to 70%. Memory 207 may store the plurality of selectable modes in one or more tables. That is, memory 207 may include the one or more tables for storing the heating profiles and the compression profiles corresponding to the selectable modes. For example, for each selectable mode the one or more tables may include the programmed time delay that is used to turn off RF generator 100 after activation of the limit switch second and third duty cycle settings to set the duty cycle of solenoid 217 in the second and third periods TP 2 and TP 3 , respectively, and first, third and fourth duration settings to set the duration of the initial, cooling and sealing periods TP 1 , TP 3 and TP 4 . By controlling the duty cycle of solenoid 217 , power requirement for sealing the tube portion are reduced. Since power requirements are reduced, solenoid 217 may be configured to reduce or eliminate the affect of heating during heavy (e.g. continuous) usage. Thus, DC resistant of the coil of solenoid 217 may be keep substantially constant such that the instantaneous compression force exerted by movement of ground jaw 26 or the tube portion does not degrade (i.e., is not reduced) over time during heavy usage. If the tube apparatus is operated by battery power or uses a portable generator, this aspect of reducing the power requirements may be especially desirable. Since nonlinearities in compression force from solenoid 217 exist, it is contemplated that by varying the duty cycle of solenoid 217 that such nonlinearities may be compensated for, thereby producing a compression force from solenoid 217 that is equivalent to a linear compression force. That is, a typical solenoid has the least compression force for a particular input current when solenoid 217 is fully extended and the most compression force for the particular input current when solenoid 217 is fully retracted. Thus, using a varying duty cycle may allow for compensation of this effect to linearize the compression force of solenoid 217 . Microcontroller 206 or memory 207 may include program code stored therein for uses by microcontroller 206 to control the tube apparatus, the program code may include a program code segment for controlling the duty cycle of solenoid 217 according to the compression profile to compress the tube portion, thereby controlling the area of the seal formed in the tube portion and or thickness T 2 of the sealed tube portion. It is contemplated that the methods previously described may be carried out within microcontroller 206 or a general purpose computer system instructed to perform these functions by means of a computer-readable medium. Such computer-readable media include; integrated circuits, magnetic and optical storage media, as well as audio-frequency, radio frequency, and optical carrier waves. A plurality of user selectable modes which each may be defined by the heating profile, for example, the programmed delay time for turning off RF generator 100 and the compression profile, for example, the duty cycles of power supplied to solenoid 217 , may be programmed into microcontroller 206 . That is, the selectable modes set the delay time to shut off RF generator 100 after activation of the limit switch (for example, as shown in FIGS. 8 a and 8 b ), and, furthermore, set, for example, the duty cycle of solenoid 217 . FIGS. 18 a and 18 b which illustrate a flow diagram showing operation of an exemplary embodiment of a tube apparatus according to this invention will now be described. Now referring to FIGS. 18 a and 18 b , for brevity, only a brief review of steps which are common with those of FIGS. 8 a and 8 b will be included below. Steps 64 - 67 which illustrate exemplary operation of the system in connection with a failed seal and steps 74 and 75 which illustrate an exemplary inoperable mode are common between this embodiment and that covered in FIGS. 8 a and 8 b and will not be further discussed. Steps 50 - 55 , 57 , 61 - 63 , and 151 - 154 roughly correspond to another exemplary sealing operation of the apparatus. Further, steps 68 , 70 - 71 , 73 , and 155 and 156 illustrate another exemplary programming mode. Referring first to the exemplary sealing operation illustrated in steps 50 - 55 , 57 , 61 - 63 , and 151 - 154 of FIGS. 18 a and 18 b , steps 50 - 55 are common between this embodiment and that covered in FIGS. 8 a and 8 b and will not be further discussed. After step 55 is complete, if the start switch has been activated, RF generator 100 (and red seal LED) may be turned on and solenoid 217 may be turned on (i.e., having a 100% duty cycle) for a predetermined time in step 150 . That is, RF generator 100 may be turned on and may remain on until the limit switch is activated or until an overall time period for making a seal elapse causing an indication of an unsuccessful seal (see steps 64 and 65 of FIGS. 18 a and 18 b ) and solenoid 217 may be turned on for a predetermined time in the range of about 0 to 200 milliseconds. By turning solenoid 217 on initially, a maximum force is applied to compress the tube portion when ground and RF jaws 26 and 42 are fully extended. This compensates for an affect that as solenoid 217 is extend the compression force produced by solenoid 217 is reduced for a constant input current level. After the predetermined time is completed, solenoid 217 is duty cycled (i.e., cycled on and off at a switching frequency in the range of about 250 Hz to 5 KHz) at a first duty cycle that is between about 10% and 90% according to the mode selected by the user in step 151 . Step 57 queries whether the limit switch is activated. If so, the programmed time delay of the selected mode is read in step 152 . In step 153 , solenoid 217 is duty cycled at a second duty cycle that is between about 40% and 64% according to the mode selected by the user. RF generator 100 is turned off after the programmed time delay of the set mode elapses in step 154 . After a predetermined time (e.g., 500 ms), which may be selected based on the amount of time desired for the seal to cool adequately, solenoid 217 (and red seal LED) is turned off in step 60 , and a count is added to memory 207 for an updated count of complete seals in step 61 . The successful seal is then completed in step 62 and the apparatus can then be readied to create another seal at step 63 . Referring now to the exemplary programming mode in steps 68 , 70 , 71 , 73 , 155 and 156 , if the cover is off (step 51 ) and the limit switch or stop sensor 204 is activated (step 68 ) during apparatus start up, then the apparatus scrolls through a menu of available modes in step 155 . Accordingly, the programming mode in steps 68 , 70 , 71 , 73 , 155 and 156 is initiated by: (1) removing the cover 12 , (2) either using start lever 33 to activate the limit switch or, otherwise, pushing ground jaw 26 in to activate the limit switch, (3) turning the apparatus on, and (4) selecting a mode. In step 70 , the power LED can flash as an indicator of a variety of selectable modes and/or an audible alarm mode. This embodiment includes four (4) modes available for selection. Each of these modes control both the timing of RF generation and the duty cycle of solenoid 217 during the sealing process of the tube portion received in the apparatus. Program mode is initiated when the shield 12 is off, the limit switch is activated, and the power is then turned on. If the cover or shield is removed after power up and the limit switch is triggered, the apparatus will not enter program mode. For example, one flash may correspond to a particular mode with a particular heating profile (e.g., a delay time to turn off RF generator 100 after the limit switch is activated) and a particular compression profile (e.g., a first duty cycle for cycling solenoid 217 after a full on predetermined period and a second duty cycle for cycling solenoid 217 after the limit switch is activated for another predetermined period). The user can activate the limit switch (step 68 ) by: either using start lever 33 to activate the limit switch or, otherwise, pushing in ground jaw shaft 24 or ground jaw 26 while the cover is off. While in the programming mode, the apparatus will continue to scroll through the menu of possible modes until the limit switch is deactivated at step 71 . In other words, if the limit switch remains activated (e.g., by the user retaining ground jaw shaft 24 in a closed position) then the apparatus will continue to scroll selectable modes. Upon release of ground jaw shaft 24 by the user, the limit switch will thereby be deactivated in step 71 and the mode selected by the user by deactivating the limit switch is then stored in the memory 207 as the selected mode in step 156 . The various programmed modes may determine the heating and compression profiles and/or the nature of the indicator with respect to failed and successful seals. For example, a menu of program modes can include modes configured to sound an audible alarm (e.g., a buzzer) in the event of a failed seal. Alternatively, modes can dictate a silent, visual alarm depending on the preferences of the end user. As indicated in step 155 , the mode selected by the user will correlate to a desired seal width. Generally, the longer the delay time (i.e., prior to turning off RF generator 100 ) and the larger the duty cycles of solenoid 217 (i.e., the higher the composite compression action of solenoid 217 ), the wider the seal may be. After step 155 , the programming mode is concluded at step 73 . Although in the embodiment shown includes four (4) user selectable modes, it is contemplated that any number of other user selectable modes may be implemented. Although in the embodiment shown the user selectable modes are preprogrammed (i.e., user selectable according to a scrolled menu), it is contemplated that an input device, such as a touch pad may be implemented to input setting to microcontroller 206 to set the mode according to unique requirements of the user by allowing the user to adjust any number of parameters established in a preprogrammed selectable mode or, otherwise, to establish a new mode for selection. Although exemplary embodiments of a tube sealer and method according to this invention have been described, there are others that support the spirit of the invention and are therefore within the contemplated scope of the invention. For example, although the dielectric tube sealer 8 is embodied as a tabletop unit, the jaw components of the system, and optionally the entire system, can be reconfigured as a hand-held unit to improve upon its portability. Also, the configuration of the jaws with respect to the cabinet can be modified. More specifically, although the jaws are shown to be extending outwardly from a cabinet 10 and covered by an external shield 12 , the jaws can be positioned entirely within the interior of a cabinet so long as access to the jaws can be provided for the insertion of a tube portion between them. Although the invention has been described with reference to tube sealers to illustrate exemplary features of the invention, this invention applies with equal benefit to all tube apparatus, whether such apparatus are used to seal, connect, weld, join, cut, or otherwise alter or manipulate tubing. For example, exemplary features of this invention can be applied to sterile tube welders or connection devices such as those used in blood bank or blood center applications. The foregoing is considered as illustrative only of the many possible variations in the illustrated configurations of the invention, and the foregoing recitation of variations should not be considered to be an exhaustive list. It will be appreciated, therefore, that other modifications can be made to the illustrated embodiment without departing from the scope of the invention. The scope of the invention is separately defined in the appended claims.

FIG. 1 depicts a full view of the picnic table backrest. It shows the backrest, the bars that wrap around the bench to keep the back rest stable and the latch on the back of the rest that keeps the rest from slipping out. FIG. 2 shows a close up view of the latch on the rear of the backrest. The bar that holds the latch swivels upward to latch on to the top part of the backrest. This keeps the backrest from slipping out and also holds it in place so it doesn't shift while your sitting.

BACKGROUND OF THE INVENTION Phosphoric acid prepared by the digestion of phosphate rock commonly contains cationic impurities such as calcium, magnesium, aluminum and iron. It is known to purify phosphoric acid by solvent extraction techniques. The organic solvent displays a greater preference for phosphoric acid than it does for the metal salt impurities in the crude phosphoric acid. Nevertheless, an undesirable residue of polyvalent cationic impurities amounting to 25 to 250 parts per million usually remains in the solvent phase. U.S. Pat. No. 3,993,733 describes a process for preparing alkaline metal phosphates by neutralizing a solvent acid phase to obtain a precipitate and thereafter neutralizing the resultant aqueous acid phase to form a solution of soluble phosphate salts. U.S. Pat. No. 3,993,736 describes a process for preparing purified phosphoric acid by first neutralizing an acid containing solvent phase to obtain a precipitate, neutralizing the resultant aqueous phase to form a solution of soluble phosphate salts, and thereafter reconverting the phosphate salts to phosphoric acid. U.S. Pat. No. 4,112,118 extracts phosphoric acid containing solvent with an alkaline solution to remove substantially all of the P 2 O 5 value of the solvent. The aqueous extract contains phosphoric acid and phosphate salts in combination. U.S. Pat. No. 4,024,225 describes a sequential neutralization procedure for preparing phosphate salts. U.S. Pat. No. 3,081,151 prepares a purified phosphate salt liquor using a two-step neutralization. Prior art processes are not adapted to the concurrent production of purified phosphoric acid and purified phosphate salt. THE INVENTION This invention is an improved solvent extraction process wherein the organic solvent extract phase from a crude phosphoric acid extraction is treated to recover both purified phosphoric acid and purified sodium phosphate salts. The process of this invention converts at least one-half of the P 2 O 5 value in the solvent extract to purified phosphoric acid. A minor fraction of the P 2 O 5 is separated from the purified acid to become purified sodium phosphate salts. The objectives of this invention are accomplished by subjecting solvent extract containing P 2 O 5 values to three neutralization steps. A first partial neutralization step withdraws a substantial part of unwanted polyvalent cations from the organic solvent extract phase without neutralizing or removing a major portion of phosphoric acid contained in the solvent phase. The resultant solvent phase is washed with water to give a purified phosphoric acid. The aqueous raffinate produced by the first step partial neutralization is sent to a second neutralization step. The second neutralization step further neutralizes the aqueous raffinate from the first partial neutralization step and results in the precipitation of unwanted cationic impurities. Thereafter, a third neutralization step takes the precipitate-free raffinate from the second neutralization and completes the neutralization to obtain a purified salt solution. DESCRIPTION OF THE INVENTION The general technique of crude phosphoric acid purification by solvent extraction is well-known and is typified by U.S. Pat. No. 3,917,805; the disclosure of which is incorporated herein by reference. The organic solvent used for extraction must be capable of dissolving phosphoric acid and have a limited miscibility with water. Suitable solvents include alcohols, ketones, amines, aldehydes, and organophosphates. Examples of solvents having utility in this invention are diethyl ether, diisopropyl ether, di-n-butyl ether, ethyl acetate, butyl acetate, amyl acetate, ethyl butyrate, n-butyl alcohol, isobutyl alcohol, amyl alcohol, isoamyl alcohol, hexanol, and octanol. Mixtures of solvents may be used if desired. Preferred solvents are the C 4 -C 8 primary, secondary and tertiary alcohols. Mixed five carbon alcohols are a particularly preferred solvent for the process of this invention. Crude phosphoric acid is extracted with organic solvent to yield; (1) a phosphoric acid enriched organic solvent phase, and (2) an aqueous raffinate phase depleted in P 2 O 5 values and containing the major part of the cationic impurities originally present in the crude acid. The process of this invention is directed to treatment of the solvent phase resulting from solvent extraction of crude phosphoric acid. FIRST STEP Partial Neutralization Organic solvent (containing P 2 O 5 values) produced by the solvent extraction of crude phosphoric acid is treated by intimate contact with a selected volume ratio of aqueous neutralizing agent containing a predetermined amount of alkaline sodium salts. The treatment of the phosphoric acid containing solvent with aqueous neutralizng agent results in the formation of two phases. The first phase (labeled N-1S) is purified organic solvent containing phosphoric acid substantially free of polyvalent cationic impurities. Typically, solvent phase N-1S has a polyvalent cation content of from about 0.1 to about 10 ppm. The second phase (labeled N-1R) from the first step neutralization is an acidic partially neutralized raffinate containing phosphate salts, phosphoric acid, and most of the polyvalent cationic impurities originally present in the solvent phase before treatment with the aqueous neutralizing agent. The aqueous neutralizing agent is a water solution of alkaline sodium salts selected from sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, sodium hydroxide, or mixtures thereof. The aqueous neutralizing agent is intimately contacted with the organic solvent in a volume ratio of 1 part aqueous neutralizing agent to from about 50 to about 300 parts of organic solvent. Preferably, the volume ratio of aqueous neutralizing agent to organic solvent is from 1:75 to 1:150. Too small an amount of neutralizing agent will be ineffective in removing the major portion of cationic impurities in the solvent phase. Conversely, too large a proportion of neutralizing agent will extract the major portion of water soluble phosphoric acid from the solvent phase and subsequently prevent recovery of purified phosphoric acid directly from the organic solvent. The quantity of neutralizing agent in the aqueous neutralizing agent should be an amount effective to neutralize no more than 40 weight percent of the phosphoric acid value in the organic solvent. The alkaline sodium salt content of the neutralizing agent should preferably be such as to neutralize from about 15 weight percent to 35 weight percent of the phosphoric acid in the organic solvent. Alkaline sodium salt levels which neutralize over 40 weight percent of the phosphoric acid value in the solvent extract convert an undesirably large proportion of phosphoric acid to phosphate salts. In addition, the amount of alkaline sodium salt used in the first step must not destroy the highly acidic character of the raffinate phase. A raffinate phase with a pH above 3 tends to release precipitate and promote equipment fouling. At the conclusion of the first step partial neutralization both phases N-1S and N-1R should be highly acidic (pH less than 2.5). The function of the first step partial neutralization is to transfer substantially all of the polyvalent cations from the organic solvent into the aqueous raffinate. The first step neutralization is advantageously carried out in an apparatus which permits effective contact of two immiscible phases. Conventional apparatus such as mixer-settler extraction batteries, columns, etc., are suitable for performing the first step partial neutralization. The phase N-1S is a purified solvent which may be conventionally processed by reextraction with water and/or phosphoric acid to release a purified acid product. Generally, 60 to 85 weight percent of the original phosphoric acid (P 2 O 5 value) in the untreated organic solvent starting material is recovered from the N-1S phase as purified phosphoric acid. The purified acid may be concentrated or further purified if desired. The solvent separated from the purified acid may be dehydrated, distilled and reused in the initial extraction of crude phosphoric acid. The aqueous raffinate phase N-1R is forwared for processing to the second neutralization step: SECOND STEP NEUTRALIZATION The second step neutralization treats only the aqueous raffinate phase (N-1R) from the first step partial neutralization. The second step neutralization gives a controlled precipitation of most of the polyvalent cation content in aqueous phase N-1R. An advantage of confining the precipitation of impurities to a separate second neutralization stage is that fine control of the precipitation process is possible, high concentration levels of unwanted cations may be maintained, and fouling of process equipment is eliminated. Second step neutralization requires the addition of alkaline sodium salts to aqueous phase N-1R in an amount effective to give a final pH in the range of 4 to 6. The final aqueous raffinate resulting from the second neutralization step is designated N-2R. Removal of cations from aqueous phase N-1R is promoted by maintaining its cation concentration as high as possible. Consequently, it is advantageous to add alkaline sodium salts in a form absent significant amounts of extraneous water. This object of limited water addition may be met by using concentrated forms of alkaline sodium salts such as solid sodium carbonate or solid sodium hydroxide. Alternatively, highly concentrated slurries or solutions of alkaline sodium salts selected from sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, sodium hydroxide, or mixtures thereof may be used. The optimum neutralization within the range of 4 to 6 may be determined by taking an aliquot portion of the aqueous raffinate and reacting it with alkaline sodium salt until precipitate no longer forms. It is generally desirable to avoid large excesses of neutralizing agents since high pH tends to solubilize precipitate and redissolve the cationic impurities. The precipitate formed by the second step neutralization is separated from aqueous raffinate N-2R. In some cases it is desirable to let the precipitate age for a time period in the range of ten minutes to six hours to promote its removal. Separation of the precipitate may be performed by conventional means such as centrifugation, filtration, or decantation. The precipitate is withdrawn from the process as waste. Aqueous raffinate N-2R is forwared for processing to the third neutralization step. THIRD NEUTRALIZATION STEP The precipitate-free raffinate (N-2R) from the second neutralization step is further neutralized in the third neutralization step to yield a purified solution of sodium phosphate salts. The purified phosphate salt solution product of the third step is designated aqueous raffinate N-3R. The third step neutralization is conducted by mixing alkaline sodium salts with raffinate N-2R to give a pH of 8 or more. The alkaline sodium salts used for the third step neutralization are selected from sodium hydroxide or sodium hydroxide in combination with one or more of sodium carbonate, sodium bicarbonate, or sodium sesquicarbonate. The presence of sodium hydroxide is generally necessary to achieve the high pH levels required for the third neutralization step. The alkaline sodium salts (containing sodium hydroxide) may be used in the form of solutions, slurries or solids. If subsequent recovery of solid phosphate salts from raffinate N-3R is desired, it is advantageous to use alkaline salts having the minimum practical water content. The exact amount of alkaline sodium salts used to neutralize raffinate N-2R will depend on the sodium phosphate salt mixture of salts desired as product. Generally, alkaline sodium salt is added to raffinate N-2R to the point where the sodium to phosphorous mole ratio of the desired phosphate salt product is achieved. Typically, useful sodium to phosphorus mole ratio are in the range from 1.6:1 to 1.9:1. For example, neutralization to a sodium to phosphorous mole ratio of 1.67 to 1 will form a solution equivalent to an equimolar mixture of disodium hydrogen phosphate and monosodium dihydrogen phosphate. Sodium tripolyphosphate may be formed by tempering and calcining this equimolar mixture of salts. The process of this invention may be used to prepare disodium phosphate, trisodium phosphate, sodium acid pyrophosphate, tetrasodium pyrophosphate, the Na 2 O--P 2 O 5 glasses (e.g. hexametaphosphate), sodium tripolyphosphate or mixtures thereof. This invention finds particular application for the preparation of laundering detergent chemicals such as sodium tripolyphosphate. Alternatively, sodium tripolyphosphate may be further processed to yield chlorinated trisodium phosphate. Phosphate salts solution N-3R resulting from the third step neutralization is advantageously processed to recover solid sodium phosphate salt products by techniques such as crystallization, drying, etc. The process of this invention is illustrated by reference to the flow diagram depicted in the FIGURE. Crude phosphoric acid prepared by the acid digestion of phosphate rock is sent via line (3) to primary solvent extraction battery (5) where it is intimately contacted with organic solvent entering the battery via line (29). The products of the primary extraction battery are a P 2 O 5 depleted aqueous raffinate stream which is withdrawn via line (7) for separate treatment and a phosphoric acid enriched solvent phase which exists via line (9). The solvent from line (9) moves to a first neutralization zone N 1 (11) where it is contacted with aqueous alkaline neutralizing agent supplied from container (13) via line (15). Sufficient neutralizing agent is taken from container (13) to neutralize approximately 25 weight percent of the phosphoric acid in the first neutralization zone (11). The first neutralization zone releases a solvent phase and an aqueous phase. The aqueous phase from the first neutralization zone is sent for further treatment as a partially neutralized raffinate via line (17). The solvent extract phase from the first neutralization zone (11) is sent via line (19) to acid release chamber (21). Water and/or dilute phosphoric acid entering chamber (21) via line (23) reextracts purified aqueous phosphoric acid product which exits via line (25) and recycles P 2 O 5 depleted solvent via line (26) to dehydration and distillation purification unit (27) where it is purified and recycled to the primary extraction battery (5) via line (29). The partially neutralized aqueous raffinate from N 1 is sent via line (17) to second neutralization zone N 2 (31). Alkaline neutralizing agent from vessel (13) is supplied via line (33) so zone (31) in an amount which yields a solution having a pH in the range of 4 to 6. The precipitate containing aqueous solution from the second neutralization zone (31) is sent to filtration unit (37) via line (35) wherein solid precipitate is filtered out and removed through line (39). Aqueous precipitate-free filtrate is sent via line (41) to the third neutralization zone N 3 (43). Neutralizing agent from vessel (13) is sent via line (45) to zone (43) to give a pH above 8 and from an aqueous phosphate salt solution. The aqueous phosphate salt solution is sent via line (47) to crystallizer and dryer unit (49) which produces a solid phosphate salt product which exist via line (51). EXAMPLE This example illustrates the practice of the invention. Materials and test conditions Crude phosphoric acid (produced by sulfuric acid digestion of phosphate rock). Analysis: 46% P 2 O 5 ; 820 ppm iron. The experiment was performed at ambient temperature and pressure. All proportions are by weight unless otherwise indicated. Method A twelve stage counter-current liquid/liquid extraction was carried out on a laboratory scale using a battery of twelve 5,000 milliliter separatory funnels.* 476 grams of crude phosphoric acid was extracted with a total of 1,568 grams of mixed C 5 aliphatic alcohols. The extraction produced 87 grams of aqueous raffinate phase (Analysis: 12.5% P 2 O 5 ; 44,860 ppm. iron) and 1,957 grams of an alcohol solvent phase containing 10.7 weight percent P 2 O 5 and 151 ppm. iron. A first step partial neutralization was conducted by shaking the organic solvent phase with 14.8 grams of 50% sodium hydroxide solution using 5,000 ml. separatory funnels in a six stage counter current extraction procedure.* This first step neutralization yielded (1) aqueous raffinate (labeled N-1R) of 147 grams containing 21.4% P 2 O 5 and 1,998 ppm. iron and (2) a purified solvent phase (labeled N-1S) of 1,824 grams containing 9.8% P 2 O 5 and 1 ppm. iron. The purified solvent phase N-1S was washed with deionized water to release purified phosphoric acid product. The aqueous raffinite phase N-1R was further treated by a second neutralization step by admixture with 30 grams of solid sodium carbonate. The second neutralization resulted in the formation of 8.7 grams of a solid precipitate containing 7% P 2 O 5 , 10,000 ppm. iron, and 168 grams of an aqueous raffinate (labeled N-2R) containing 18.4% P 2 O 5 and 1,120 ppm. iron. Aqueous raffinate N-2R was filtered on 10.2 cm. filter paper in a Buchner funnel to remove the precipitate. A third neutralization was performed by mixing aqueous raffinate N-2R with 4.65 grams of solid sodium carbonate to achieve a sodium to phosphorus ratio of 1.7. Thereafter, the neutralization was completed by adding 4.67 grams of 50% sodium hydroxide to give a phosphate salt solution having a sodium to phosphorus ratio of 1.8 and a pH of 8.8. The product of the third step neutralization was 175 grams of a 39% disodium phosphate solution. The phosphate solution was dried and yielded 68.4 grams of solid disodium phosphate. This example shows the concurrent preparation of purified phosphoric acid and sodium phosphate salts. Approximately 15% of the P 2 O 5 content orginally in the organic solvent phase was converted to sodium phosphate salts. The balance of the P 2 O 5 in the original organic solvent was withdrawn as purified phosphoric acid. Iron, a typical cationic impurity, was effectively removed from the phosphoric acid product. In addition, a major part of the iron was removed from the phosphate salt product. Having now a fully described the process of this invention, it will be apparent that many modifications can be made thereto without departing from the scope of the invention as set forth herein.

Disclosed is a process for concurrently preparing purified phosphoric acid and purified sodium phosphate salts by employing a solvent extraction process with three neutralization steps.

BACKGROUND OF INVENTION 1. Field of the Invention Embodiments disclosed herein relate generally to drill bits, and more particularly to impregnated drill bits and the methods for the manufacture of such drill bits. 2. Background Art An earth-boring drill bit is typically mounted on the lower end of a drill string and is rotated by rotating the drill string at the surface or by actuation of downhole motors or turbines, or by both methods. When weight is applied to the drill string, the rotating drill bit engages the earth formation and proceeds to form a borehole along a predetermined path toward a target zone. Different types of bits work more efficiently against different formation hardnesses. For example, bits containing inserts that are designed to shear the formation frequently drill formations that range from soft to medium hard. These inserts often have polycrystalline diamond compacts (PDC's) as their cutting faces. Roller cone bits are efficient and effective for drilling through formation materials that are of medium to hard hardness. The mechanism for drilling with a roller cone bit is primarily a crushing and gouging action, in which the inserts of the rotating cones are impacted against the formation material. This action compresses the material beyond its compressive strength and allows the bit to cut through the formation. For still harder materials, the mechanism for drilling changes from shearing to abrasion. For abrasive drilling, bits having fixed, abrasive elements are preferred. While bits having abrasive polycrystalline diamond cutting elements are known to be effective in some formations, they have been found to be less effective for hard, very abrasive formations such as sandstone. For these hard formations, cutting structures that comprise particulate diamond, or diamond grit, impregnated in a supporting matrix are effective. In the discussion that follows, components of this type are referred to as “diamond impregnated.” Diamond impregnated drill bits are commonly used for boring holes in very hard or abrasive rock formations. The cutting face of such bits contains natural or synthetic diamonds distributed within a supporting material to form an abrasive layer. During operation of the drill bit, diamonds within the abrasive layer are gradually exposed as the supporting material is worn away. The continuous exposure of new diamonds by wear of the supporting material on the cutting face is the fundamental functional principle for impregnated drill bits. The construction of the abrasive layer is of critical importance to the performance of diamond impregnated drill bits. The abrasive layer typically contains diamonds and/or other super-hard materials distributed within a suitable supporting material. The supporting material must have specifically controlled physical and mechanical properties in order to expose diamonds at the proper rate. Metal-matrix composites are commonly used for the supporting material because the specific properties can be controlled by modifying the processing or components. The metal-matrix usually combines a hard particulate phase with a ductile metallic phase. The hard phase often consists of tungsten carbide and other refractory or ceramic compounds. Copper or other nonferrous alloys are typically used for the metallic binder phase. Common powder metallurgical methods, such as hot-pressing, sintering, and infiltration are used to form the components of the supporting material into a metal-matrix composite. Specific changes in the quantities of the components and the subsequent processing allow control of the hardness, toughness, erosion and abrasion resistance, and other properties of the matrix. Proper movement of fluid used to remove the rock cuttings and cool the exposed diamonds is important for the proper function and performance of diamond impregnated bits. The cutting face of a diamond impregnated bit typically includes an arrangement of recessed fluid paths intended to promote uniform flow from a central plenum to the periphery of the bit. The fluid paths usually divide the abrasive layer into distinct raised ribs with diamonds exposed on the tops of the ribs. The fluid provides cooling for the exposed diamonds and forms a slurry with the rock cuttings. The slurry must travel across the top of the rib before reentering the fluid paths, which contributes to wear of the supporting material. An example of a prior art diamond impregnated drill bit is shown in FIG. 1 . The impregnated bit 10 includes a bit body 12 and a plurality of ribs 14 that are formed in the bit body 12 . The ribs 14 are separated by channels 16 that enable drilling fluid to flow between and both clean and cool the ribs 14 . The ribs 14 are typically arranged in groups 20 where a gap 18 between groups 20 is typically formed by removing or omitting at least a portion of a rib 14 . The gaps 18 , which may be referred to as “fluid courses,” are positioned to provide additional flow channels for drilling fluid and to provide a passage for formation cuttings to travel past the drill bit 10 toward the surface of a wellbore (not shown). Impregnated bits are typically made from a solid body of matrix material formed by any one of a number of powder metallurgy processes known in the art. During the powder metallurgy process, abrasive particles and a matrix powder are infiltrated with a molten binder material. Upon cooling, the bit body includes the binder material, matrix material, and the abrasive particles suspended both near and on the surface of the drill bit. The abrasive particles typically include small particles of natural or synthetic diamond. Synthetic diamond used in diamond impregnated drill bits is typically in the form of single crystals. However, thermally stable polycrystalline diamond (TSP) particles may also be used. In one impregnated bit forming process, the shank of the bit is supported in its proper position in the mold cavity along with any other necessary formers, e.g. those used to form holes to receive fluid nozzles. The remainder of the cavity is filled with a charge of tungsten carbide powder. Finally, a binder, and more specifically an infiltrant, typically a nickel brass copper based alloy, is placed on top of the charge of powder. The mold is then heated sufficiently to melt the infiltrant and held at an elevated temperature for a sufficient period to allow it to flow into and bind the powder matrix or matrix and segments. For example, the bit body may be held at an elevated temperature (>1800° F.) for a period on the order of 0.75 to 2.5 hours, depending on the size of the bit body, during the infiltration process. By this process, a monolithic bit body that incorporates the desired components is formed. One method for forming such a bit structure is disclosed in U.S. Pat. No. 6,394,202 (the '202 patent), which is assigned to the assignee of the present invention and is hereby incorporated by reference. Referring now to FIG. 2 , a drill bit 22 in accordance with the '202 patent comprises a shank 24 and a crown 26 . Shank 24 is typically formed of steel and includes a threaded pin 28 for attachment to a drill string. Crown 26 has a cutting face 29 and outer side surface 30 . According to one embodiment, crown 26 is formed by infiltrating a mass of tungsten-carbide powder impregnated with synthetic or natural diamond, as described above. Crown 26 may include various surface features, such as raised ridges 32 . Preferably, formers are included during the manufacturing process so that the infiltrated, diamond-impregnated crown includes a plurality of holes or sockets 34 that are sized and shaped to receive a corresponding plurality of diamond-impregnated inserts 36 . Once crown 26 is formed, inserts 36 are mounted in the sockets 34 and affixed by any suitable method, such as brazing, adhesive, mechanical means such as interference fit, or the like. As shown in FIG. 2 , the sockets can each be substantially perpendicular to the surface of the crown. Alternatively, and as shown in FIG. 2 , holes 34 can be inclined with respect to the surface of the crown 26 . In this embodiment, the sockets are inclined such that inserts 36 are oriented substantially in the direction of rotation of the bit, so as to enhance cutting. To form such bits using a powder metallurgy process, as described above, abrasive particles (often diamonds) are placed in a mold, which is then packed with a matrix powder, and infiltrated with a molten binder material to result in the abrasive particles suspended both near and on the surface of the drill bit. In packing the matrix powder materials into the mold, the geometry of the bit (and thus mold) make it difficult to place different matrix materials in different regions of a bit because there is little or no control over powder locations in the mold during assembly, particularly around curved surfaces (shoulder and gage). Thus, a single matrix powder material is typically selected for use in packing the entire bit. Typically, a softer matrix material may be selected so allow for higher rate of penetrations to be achieved, due to the relative easier wear of the matrix material in exposing the diamonds for cutting. However, it may be preferable to use not as soft as a material or the shoulder or gage of the bit may wear down prematurely. Further, too hard of a matrix material would likely create a brittle cone, nose and shoulder area of the bit, resulting in rib cracking and breakage. Thus, frequently, to allow for the use of such softer materials (for ROP), diamond inserts (including diamond impregnated inserts such as the type discussed in the '202 patent described above, PCD inserts or TSP wafers) are frequently brazed or cast into the gage area. However, for extremely abrasive formations or horizontal drilling applications, for example, the use of softer materials (desired for ROP) may still result in premature wearing away, which may lead to pull-out of the inserts or diamond grit particles (due to an increased load) or wear of the gage to an “under-gage” status. Accordingly, there exists a continuing need for improvements in diamond impregnated cutting structures to improve rate of penetration without sacrificing durability. SUMMARY OF INVENTION In one aspect, embodiments disclosed herein relate to a drill bit that includes a body having a lower end face for engaging a rock formation, the end face having a plurality of raised ribs extending from the face of the bit body and separated by a plurality of channels therebetween; and at least one of the plurality of ribs having a cutting portion of the at least one rib comprising a first diamond impregnated matrix material and at least a portion of a gage surface region thereof comprising a second diamond impregnated matrix material, the gage surface region backed by a third matrix material. In another aspect, embodiments disclosed herein relate to a drill bit that includes a body having a lower end face for engaging a rock formation, the end face having a plurality of raised ribs extending from the face of the bit body and separated by a plurality of channels therebetween; and at least one of the plurality of ribs having a cutting portion of the at least one rib comprising a first diamond impregnated matrix material and at least a portion of a gage surface region thereof comprising a second diamond impregnated matrix material harder than the first diamond impregnated matrix material. In another aspect, embodiments disclosed herein relate to a drill bit that includes a body having a lower end face for engaging a rock formation, the end face having a plurality of raised ribs extending from the face of the bit body and separated by a plurality of channels therebetween; at least one of the plurality of ribs comprising, at a portion of a base of the at least one rib extending from the face of the bit body along a sidewall, a first diamond impregnated matrix material, the at least one rib comprising a second diamond impregnated matrix material in a remaining portion of the at least one rib, the second diamond impregnated matrix material being harder than the first diamond impregnated matrix material. In yet another aspect, embodiments disclosed herein relate to a method of manufacturing a drill bit including a bit body and a plurality of ribs extending from the bit body that includes adhering a plurality of abrasive particles and a first matrix material to at least a vertical portion of a mold cavity corresponding to at least one of the plurality of ribs; loading a plurality of abrasive particles and a second matrix material into the other portions of the mold cavity; and heating the mold contents to form an impregnated drill bit. In yet another aspect, embodiments disclosed herein relate to a method of manufacturing a drill bit including a bit body and a plurality of ribs extending from the bit body that includes loading a plurality of abrasive particles and a first matrix material in at least a portion of a mold cavity corresponding to a gage portion of at least one of the plurality of ribs; loading a plurality of abrasive particles and a second matrix material into the other portions of the mold cavity; and heating the mold contents to form an impregnated drill bit. Other aspects and advantages of the invention will be apparent from the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a prior art impregnated bit. FIG. 2 is a prior art impregnated bit. FIG. 3 shows a top view of a drill bit in accordance with one embodiment of the present disclosure. FIG. 4 shows a cross-sectional view of a rib along 4 - 4 of the bit of FIG. 3 . FIG. 5 shows a cross-sectional view of a rib in accordance with an alternate embodiment. FIG. 6 shows a cross-sectional view of a rib in accordance with an alternate embodiment. FIG. 7 shows a cross-sectional view of a rib in accordance with an alternate embodiment. FIG. 8 shows a cross-sectional view along 8 - 8 of the bit of FIG. 3 . FIG. 9 shows a cross-sectional view of a rib in accordance with an alternate embodiment. FIG. 10 shows a perspective view of a rib in accordance with one embodiment. DETAILED DESCRIPTION In one aspect, embodiments disclosed herein relate to impregnated drill bits and the methods of manufacturing and using the same. More particularly, embodiments disclosed herein relate to impregnated drill bits having tailored material compositions allowing for extension of their use downhole. Specifically, embodiments disclosed herein relate to impregnated drill bits having ribs with harder gage portions and/or tougher supporting base/sidewalls. Referring to FIGS. 3-4 , a drill bit in accordance with one embodiment is shown. As shown in FIGS. 3-4 , impregnated bit 30 includes a bit body 32 and a plurality of ribs 34 that are extending from the bit body 32 . Ribs may extend from a center of the bit body radially outward to the outer diameter of the bit body 32 , and then axially downward, to define the diameter (or gage) of the bit 30 . The ribs 34 are separated by channels 36 that enable drilling fluid to flow between and both clean and cool the ribs 34 . Each rib 34 has a profile 38 defining its general shape/geometry that may be divided into various segments: a cone region 42 (recessed central area), a nose region 44 (leading cutting edge of profile), a shoulder region 46 (beginning of outside diameter of bit), transition region 47 (transition between shoulder and vertical gage), and a gage region 48 (vertical region defining outer diameter of bit). The primary cutting portion of the rib 34 includes cone region 42 , nose region 44 , and shoulder region 46 , whereas gage region 48 is primarily responsible for maintaining the hole size. In a conventional impregnated bit, such as formed by infiltrating techniques, a mixture of diamond particles and matrix particles are poured into the rib portions (and a portion of the interior bit body), a softer, machinable powder is typically poured on top of the diamond mixture (thus occupying at least a portion of the mold corresponding to the gage region of the ribs), and the bit is infiltrated with an infiltration binder. However, in accordance with the present disclosure, at least a portion a rib's gage surface is formed using a hard matrix material. As shown in FIG. 4 , a portion of gage region 48 is occupied by a diamond impregnated material 40 unique as compared to the material(s) used in the remaining portions of the rib 34 and body 32 . In a particular embodiment, diamond impregnated material 40 may be tailored to have a material composition harder than the remaining portions of the rib 34 . An alternate embodiment is shown in FIG. 5 . As shown in FIG. 5 , rib 34 is similarly divided into cone region 42 , nose region 44 , shoulder region 46 , transition region 47 , and gage region 48 . However, as compared to FIG. 4 , diamond impregnated material 40 extend beyond the gage region 48 , through transition region 47 , and into shoulder region 46 . Diamond impregnated material 40 may be found a selected distance D into the rib 34 from the surface thereof. The cutting portions of rib 34 may be formed of a second diamond impregnated material 43 , while diamond impregnated material 40 at gage region 48 may be backed by a third material 45 . In a particular embodiment, it may be desirable to have a cutting portion with a diamond impregnated material 43 tailored to allow for relative ease in diamond exposure to provide improvements in rate of penetration, while forming a gage region 48 with a diamond impregnated material 40 harder than cutting diamond impregnated material 43 so that risk of drilling under gage may be minimized. Further, while such a hard material may be desirable for the gage surface, the backing of diamond impregnated material 40 (or at least a gage portion thereof) may be achieved with a tougher, softer material 45 that is machinable for manufacturing ease. In a particular embodiment, such distance D may be greater than 2 mm (so as to allow for placement of a single layer of diamond particles). However, in other particular embodiments, the thickness may range from 3 to 15 mm. Referring to FIG. 6 , yet another embodiment of a rib 34 is shown. As shown in FIG. 6 , rib 34 includes diamond impregnated material 40 extending from gage region 48 into shoulder region 46 , diamond impregnated material 43 in a cutting portion of the rib, and a material 45 as an inner bit body material. Additionally, rib 34 includes sockets 62 in which preformed impregnated inserts 64 may be affixed. Such inserts 64 may extend along the entire rib profile 38 , including into gage region 48 . Preformed inserts may include a consolidated or hot pressed insert, such as the type described in U.S. Pat. No. 6,394,202, which is assigned to the present assignee and herein incorporated by reference in its entirety. Similar to other embodiments of impregnated ribs, such preformed inserts may include super abrasive particles dispersed within a continuous matrix material, such as the materials described below in detail. Further, such preformed inserts may be formed from encapsulated particles, as described in U.S. Patent Publication No. 2006/0081402 and U.S. application Ser. Nos. 11/779,083, 11/779,104, and 11/937,969. Further, as is also shown in FIG. 6 , superabrasive wafer elements 66 , such as TSP or PCD wafers may be affixed to the surface of gage region 48 of bit to increase the hardness of such exterior portion of the bit. Use of such features (preformed inserts or cutting elements) affixed to the gage region is known in the art, thus, it is within the scope of the present disclosure that such features (or any other features) known in the art of diamond impregnated bits may be used in conjunction with the embodiments of the present disclosure. Now referring to FIG. 7 , it also is within the scope of the present disclosure that the overall hardness of the gage region may be altered by the use of a preformed impregnated insert(s) 68 having a greater hardness, as compared to the radially inward inserts 64 on the rib 34 . It is also within the scope of the present disclosure that other such “vertical” surfaces may be tailored to a particular desirable bit application. For example, referring to FIG. 8 , another embodiment of a rib 34 of the present disclosure is shown. As shown in FIG. 8 , rib 34 extends from bit body 32 a selected height H. Thus, area from which rib 34 extends from bit body 32 is referred to as base 82 . As shown in FIG. 8 , at least a portion of base 82 , extending a selected height H along the sidewall 84 of rib 34 , is formed from a diamond impregnated material 80 , whereas the remaining portion of the rib (primarily forming the top cutting surface 88 ) is formed from a diamond impregnated material 86 . Further, while diamond impregnated material 86 is shown as being continuous with bit body 32 , one skilled in the art would appreciate that likely, the bit body may be formed of a material unique from the diamond impregnated ribs. The combination of multiple materials to form different segments of a rib may allow for greater tailoring depending on the particular application. For example, use of a tougher diamond impregnated material 80 may produce generally tougher ribs, particularly as rib height increase, to prevent rib cracking. Referring to FIG. 9 , an alternate embodiment is shown. As shown in FIG. 9 , diamond impregnated material 80 may extend the entire length of the sidewall 84 from a base 82 to the cutting top of the rib 34 , with diamond impregnated material 86 forming the remaining portion of rib 34 . Thus, the height H of diamond impregnated material 80 may range from 10 mm to the entire height of rib 34 . Referring to FIG. 10 , yet another embodiment of rib 34 is shown. As shown in rib 34 , rib 34 includes a cone region 42 , nose region 44 , shoulder region 46 (all forming the primary cutting portion of the rib 34 ), and gage region 48 . A surface portion of the gage region 48 may be formed from diamond impregnated material 40 (a selected distance D into rib 34 ), a base portion 82 of rib 34 (where rib 34 extends from bit body (not shown)) may be formed from diamond impregnated material 80 a selected height H, while the remainder of (including top cutting surface 88 ) of the collective primary cutting portion 42 , 44 , 46 may be formed from diamond impregnated material 43 . Further, a matrix material 45 may back diamond impregnated material 40 on the gage surface. In a particular embodiment, comparing all of the various materials, the materials may all be selected to having differing material properties (hardness) such that diamond impregnated material 40 is the hardest material, followed in hardness by diamond impregnated material 43 , then diamond impregnated material 80 , and then matrix material 45 . Another embodiment could be such that diamond impregnated material 40 is the hardest material, followed in hardness by diamond impregnated material 80 , then diamond impregnated material 43 , and then matrix material 45 . Further, one skilled in the art would appreciate that a bit body material (while not shown) may also be provided as a different material than those shown. In a particular embodiment, diamond impregnated material 40 may extend along the entire gage surface to the shank (not shown). Further, as shown in FIG. 10 , preformed inserts 64 may be included along the entire rib profile, including on the top cutting surface and gage surface. Additionally, super abrasive elements may be affixed to the surface of gage region as well. Further, one skilled in the art would appreciate that while various features or aspects of the present disclosure have all been shown in various combinations in the various figures, any combination of some or all of such features is within the scope of the present disclosure. Thus, embodiments of the present disclosure provide an impregnated drill bit having various vertical portions of a rib of formed of a unique material, as compared to a neighboring region of the rib. For example, the various portions may be formed from various combinations of matrix material impregnated with super abrasive particles (and/or matrix material without super abrasives). Further, in a particular embodiment, the different regions may be formed of materials to result in a hardness difference of at least 7 HRC and up to 50 HRC between two neighboring regions of the rib. This difference between the materials used in certain portions of a rib may include variations in chemical make-up or particle size ranges/distribution, which may translate, for example, into a difference in wear or erosion resistance properties of the rib portions. Thus, for example, different types of carbide (or other hard) particles may be used among the different types of matrix materials. One of ordinary skill in the art would appreciate that a particular variety of tungsten carbide, for example, may be selected based on hardness/wear resistance. The hardness of the material may also be varied by altering the amount, type, etc., of super abrasive particles. Further, chemical make-up of a matrix powder material may also be varied by altering the percentages/ratios of the amount of hard particles as compared to binder powder. Thus, by decreasing the amount of tungsten carbide particle and increasing the amount of binder powder in a portion of the rib, a softer portion of the rib may be obtained, and vice versa. In a particular embodiment, the matrix materials may be selected so that a gage region may include a harder material (as compared to the primary cutting portion of the rib), and/or a base region of the rib may include a tougher, softer material (as compared to the primary cutting surface of the rib). Additionally, in various embodiments, the various portions may be formed of encapsulated particles to provide for impregnation described above. The use of encapsulated particles in cutting structures is described for example in U.S. Patent Publication No. 2006/0081402 and U.S. application Ser. Nos. 11/779,083, 11/779,104, and 11/937,969, all of which are assigned to the present assignee, and herein incorporated by reference in their entireties. Briefly, encapsulated particles are formed of super abrasive particles coated or surrounded by encapsulating shell of matrix powder material. The encapsulated particles may be infiltrated with an infiltrating material that may include an infiltration binder and an optional matrix powder material. Thus, in forming a rib, different types, amounts of encapsulated particles may be used in the various regions of the rib and/or encapsulated particles may be used in one region and not others, etc. Super Abrasive Particles The super abrasive particles may be selected from synthetic diamond, natural diamond, reclaimed natural or synthetic diamond grit, cubic boron nitride (CBN), thermally stable polycrystalline diamond (TSP), silicon carbide, aluminum oxide, tool steel, boron carbide, or combinations thereof. In various embodiments, the gage portion may be impregnated with particles selected to result in a harder gage surface as compared to the cutting portion. Thus, the impregnated particles may be selected to differ in type (i.e., chemical composition), quality (strength), size, concentration, and/or retention coatings, all of which may alter the resulting materials properties of the rib portions. The shape of the abrasive particles may also be varied as abrasive particles may be in the shape of spheres, cubes, irregular shapes, or other shapes. In some embodiments, abrasive particles may range in size from 0.2 to 2.0 mm in length or diameter; from 0.3 to 1.5 mm in other embodiments; from 0.4 to 1.2 mm in other embodiments; and from 0.5 to 1.0 mm in yet other embodiments. However, particle sizes are often measured in a range of mesh sizes, for example −40+80 mesh. The term “mesh” actually refers to the size of the wire mesh used to screen the particles. For example, “40 mesh” indicates a wire mesh screen with forty holes per linear inch, where the holes are defined by the crisscrossing strands of wire in the mesh. The hole size is determined by the number of meshes per inch and the wire size. The mesh sizes referred to herein are standard U.S. mesh sizes. For example, a standard 40 mesh screen has holes such that only particles having a dimension less than 420 μm can pass. Particles having a size larger than 420 μm are retained on a 40 mesh screen and particles smaller than 420 μm pass through the screen. Therefore, the range of sizes of the particles is defined by the largest and smallest grade of mesh used to screen the particles. Particles in the range of −16+40 mesh (i.e., particles are smaller than the 16 mesh screen but larger than the 40 mesh screen) will only contain particles larger than 420 μm and smaller than 1190 μm, whereas particles in the range of −40+80 mesh will only contain particles larger than 180 μm and smaller than 420 μm. Thus, in some embodiments, abrasive particles may include particles not larger than would be filtered by a screen of 10 mesh. In other embodiments, abrasive particles may range in size from −15+35 mesh. In a particular embodiment, the leading portion may include abrasive particles ranging in size from −25+35 mesh, while the trailing portion may include abrasive particles ranging in size from −20+25 mesh. However, one of ordinary skill would recognize that the particle sizes and distribution of the particle sizes of the abrasive particles may be selected to allow for a broad, uniform, or bimodal distribution, for example, depending on a particular application, and that size ranges outside the distribution discussed above may also be selected. Further, although particle sizes or particle diameters are referred to, it is understood by those skilled in the art that the particles may not necessarily be spherical in shape. Further, as discussed above, various abrasive particles that may be selected for use in the ribs may vary in type (i.e., chemical composition) such that the various portions of a rib may use different types of abrasive particles; however, one of ordinary skill in the art would appreciate that among these particles, there may also be a difference in compressive strength of the particles. For example, some synthetic diamond grit may have a greater compressive strength than natural diamond grit and/or reclaimed grit. Furthermore, even within the general synthetic grit type, there may exist different grades of grit having differing compressive strengths, such as those grades of grit commercially available from Element Six Ltd. (Berkshire, England). For example, recycled diamond grit (reduced strength due to multiple high temperature exposures) could be used as the abrasive particles within one segment so as to render that segment less wear resistant than a neighboring segment. In addition to varying the strength of the abrasive particles, the presence and chemical identity of a retention coating on the surface of the abrasive particle may also optionally be varied. Such retention coatings may be applied by conventional techniques such as CVD or PVD. One of ordinary skill in the art would appreciate that the thin coatings (having a thickness of only a few micrometers) may be more helpful for high temperature protection (e.g., SiC coatings) while others are helpful for grit retention (e.g., TiC). In certain embodiments, the retention coating (TiC in the above example) may help bond the diamond to the “outer” matrix material in which the abrasive particles are impregnated. Additionally, in certain applications the retention coating may reduce thermal damage to the particles. For example, different coatings may be used between abrasive particles on the various rib portions, such as for example, a weaker PVD coating could be applied on the particles in a first segment of the rib, and a stronger CVD coating on abrasive particles in a second segment of the rib, leading to a less wear resistant first segment. One example is to use a high temperature protection coating, such as SiC for gage area diamond grit ( 43 and 64 ) for improved thermal protection, and thus improved wear resistance on gage, while using lower temperature coating, such as TiC, for regions 43 and 80 to maintain good ROP performance. Matrix Material The impregnated particles may be dispersed in a continuous matrix material formed from a matrix powder and infiltrating binder material. The matrix powder material may include a mixture of a carbide compounds and/or a metal alloy using any technique known to those skilled in the art. For example, matrix powder material may include at least one of macrocrystalline tungsten carbide particles, carburized tungsten carbide particles, cast tungsten carbide particles, and sintered tungsten carbide particles. In other embodiments non-tungsten carbides of vanadium, chromium, titanium, tantalum, niobium, and other carbides of the transition metal group may be used. In yet other embodiments, carbides, oxides, and nitrides of Group IVA, VA, or VIA metals may be used. Typically, a binder phase may be formed from a powder component and/or an infiltrating component. In some embodiments of the present invention, hard particles may be used in combination with a powder binder such as cobalt, nickel, iron, chromium, copper, molybdenum and their alloys, and combinations thereof. In various other embodiments, an infiltrating binder may include a Cu—Mn—Ni alloy, Ni—Cr—Si—B—Al—C alloy, Ni—Al alloy, and/or Cu—P alloy. In other embodiments, the infiltrating matrix material may include carbides in amounts ranging from 0 to 70% by weight in addition to at least one binder in amount ranging from 30 to 100% by weight thereof to facilitate bonding of matrix material and impregnated materials. Further, with respect to particle sizes, each type of matrix material (for respective portions of a rib) may be individually be selected from particle sizes that may range in various embodiments, for example, from about 1 to 200 micrometers, from about 1 to 150 micrometers, from about 10 to 100 micrometers, and from about 5 to 75 micrometers in various other embodiments or may be less than 50, 10, or 3 microns in yet other embodiments. In a particular embodiment, each type of matrix material (for respective rib segments) may have a particle size distribution individually selected from a mono, bi- or otherwise multi-modal distribution. One of ordinary skill in the art would appreciate that the type of matrix materials, i.e., the types and relative amounts of tungsten carbide, for example, may be selected based on the location of their use in a mold, so that the various rib portions have the desired hardness/wear resistance for the given location. In addition to varying the type of tungsten carbide (as the various types of tungsten carbide have inherent differences in material properties that result from their use), the chemical make-up of a matrix powder material may also be varied by altering the percentages/ratios of the amount of hard particles as compared to binder powder. Thus, by decreasing the amount of tungsten carbide particle and increasing the amount of binder powder in a portion of the rib, a softer portion of the rib may be obtained, and vice versa. Types of Tungsten Carbide Tungsten carbide is a chemical compound containing both the transition metal tungsten and carbon. This material is known in the art to have extremely high hardness, high compressive strength and high wear resistance which makes it ideal for use in high stress applications. Its extreme hardness makes it useful in the manufacture of cutting tools, abrasives and bearings, as a cheaper and more heat-resistant alternative to diamond. Sintered tungsten carbide, also known as cemented tungsten carbide, refers to a material formed by mixing particles of tungsten carbide, typically monotungsten carbide, and particles of cobalt or other iron group metal, and sintering the mixture. In a typical process for making sintered tungsten carbide, small tungsten carbide particles, e.g., 1-15 micrometers, and cobalt particles are vigorously mixed with a small amount of organic wax which serves as a temporary binder. An organic solvent may be used to promote uniform mixing. The mixture may be prepared for sintering by either of two techniques: it may be pressed into solid bodies often referred to as green compacts; alternatively, it may be formed into granules or pellets such as by pressing through a screen, or tumbling and then screened to obtain more or less uniform pellet size. Such green compacts or pellets are then heated in a vacuum furnace to first evaporate the wax and then to a temperature near the melting point of cobalt (or the like) to cause the tungsten carbide particles to be bonded together by the metallic phase. After sintering, the compacts are crushed and screened for the desired particle size. Similarly, the sintered pellets, which tend to bond together during sintering, are crushed to break them apart. These are also screened to obtain a desired particle size. The crushed sintered carbide is generally more angular than the pellets, which tend to be rounded. Cast tungsten carbide is another form of tungsten carbide and has approximately the eutectic composition between bitungsten carbide, W 2 C, and monotungsten carbide, WC. Cast carbide is typically made by resistance heating tungsten in contact with carbon, and is available in two forms: crushed cast tungsten carbide and spherical cast tungsten carbide. Processes for producing spherical cast carbide particles are described in U.S. Pat. Nos. 4,723,996 and 5,089,182, which are herein incorporated by reference. Briefly, tungsten may be heated in a graphite crucible having a hole through which a resultant eutectic mixture of W 2 C and WC may drip. This liquid may be quenched in a bath of oil and may be subsequently comminuted or crushed to a desired particle size to form what is referred to as crushed cast tungsten carbide. Alternatively, a mixture of tungsten and carbon is heated above its melting point into a constantly flowing stream which is poured onto a rotating cooling surface, typically a water-cooled casting cone, pipe, or concave turntable. The molten stream is rapidly cooled on the rotating surface and forms spherical particles of eutectic tungsten carbide, which are referred to as spherical cast tungsten carbide. The standard eutectic mixture of WC and W 2 C is typically about 4.5 weight percent carbon. Cast tungsten carbide commercially used as a matrix powder typically has a hypoeutectic carbon content of about 4 weight percent. In one embodiment of the present invention, the cast tungsten carbide used in the mixture of tungsten carbides is comprised of from about 3.7 to about 4.2 weight percent carbon. Another type of tungsten carbide is macro-crystalline tungsten carbide. This material is essentially stoichiometric WC. Most of the macro-crystalline tungsten carbide is in the form of single crystals, but some bicrystals of WC may also form in larger particles. Single crystal monotungsten carbide is commercially available from Kennametal, Inc., Fallon, Nev. Carburized carbide is yet another type of tungsten carbide. Carburized tungsten carbide is a product of the solid-state diffusion of carbon into tungsten metal at high temperatures in a protective atmosphere. Sometimes it is referred to as fully carburized tungsten carbide. Such carburized tungsten carbide grains usually are multi-crystalline, i.e., they are composed of WC agglomerates. The agglomerates form grains that are larger than the individual WC crystals. These large grains make it possible for a metal infiltrant or an infiltration binder to infiltrate a powder of such large grains. On the other hand, fine grain powders, e.g., grains less than 5 μm, do not infiltrate satisfactorily. Typical carburized tungsten carbide contains a minimum of 99.8% by weight of WC, with total carbon content in the range of about 6.08% to about 6.18% by weight. Referring back to FIG. 10 , in a particular embodiment, various combinations of materials suitable for use in the present disclosure are envisioned. In a particular embodiment, diamond impregnated material 40 in gage region 48 may be formed from 120 concentration 25/35 mesh SiC coated grit with a hard GM 55 matrix (available from Smith International, Inc. (Houston, Tex.)). Diamond impregnated material 80 along the base 82 of rib 34 may be formed from 80 concentration 20/25 mesh TiC coated grit with soft GM52 matrix (available from Smith International, Inc. (Houston, Tex.)). Diamond impregnated material 43 , forming the primary cutting portion of rib 34 , may be formed from 100 concentration 20/25 mesh TiC coated grit with soft GM52 matrix material (available from Smith International, Inc. (Houston, Tex.)). Finally, matrix material 45 , backing the diamond impregnated material 40 , may be formed from a tungsten/nickel powder, also known as a machinable shoulder powder. As discussed above, combinations of materials (and material properties) may be used in forming the ribs of the present disclosure. It is specifically within the scope of the present disclosure that materials may be selected for the various regions of the rib to provide a differential in hardness/toughness, etc, depending on the loads and potential failure modes frequently experienced by that region of the rib. For example, in a particular embodiment, a base of a rib may be formed of a less hard or tougher material than the top height of the rib so as to provide greater support and durability to the rib, and reduce or prevent the incidents of rib breakage, which may be experienced particularly as rib height increases. Further, it is also within the scope of the present disclosure to provide a gage surface that has an increased hardness, so as to prevent or reduce the incidents of drilling undergage, while avoiding use of such harder materials in the primary cutting region which would be too brittle and likely result in rib cracking and breakage. In particular, steerable bits and horizontal drilling applications require a harder gage area to resist the high stress three-body abrasive wear, making bits of the present application particularly suitable for use in such applications. The ribs of the present disclosure have vertically oriented portions thereof (when formed in a mold) tailored with a varying material composition depending on the particular region of the rib, unattainable by conventional powder metallurgy techniques. Manufacturing of a bit in accordance with the present disclosure may begin with the fabrication of a mold, having the desired body shape and component configuration, including rib geometry. Using conventional powder metallurgy, creating a surface gage region (or other vertical surface) from a separate powder material (as compared to neighboring regions of a rib would be infeasible, if not impossible, as within a mold, the powders would too easily mix together. However, in accordance with embodiments of the present disclosure, a mixture of matrix material and diamond (for example, in a clay-like mixture) may be loaded into the mold, and place in the desired location of the mold, corresponding to the regions of the rib desired to have different material properties. The other regions or portions of the rib may be filled with a differing material, and the ribs may be infiltrated with a molten infiltration binder and cooled to form a bit body. Optionally, a matrix material, and optionally a metal binder powder, may be loaded on top of the diamond mixtures loaded in the rib portions. In a particular embodiment, during infiltration a loaded matrix material may be carried down with the molten infiltrant to fill any gaps between the particles. Further, one skilled on the art would appreciate that other techniques such as casting may alternatively be used. In a particular embodiment, the materials (diamond and matrix powder) may be combined as premixed pastes, which may then be packed into the mold in the respective portions of the mold, such that along the vertical gage surface and/or sidewall of the rib. By using a paste-like mixture of superabrasives, carbides, and metal powders, the mixture may possess structural cohesiveness beneficial in forming a rib having the material make-up disclosed herein. Additionally, the material may be formable or moldable, similar to clay, which may allow for the material to be shaped to have the desired thickness, shape, contour, etc., when placed or positioned in a mold. Further, as a result of the structural cohesiveness, when placed in a mold, the material may hold in place without encroaching the opposing portion of the mold cavity. To be moldable, such materials may have a viscosity of at least about 250,000 cP. However, in other embodiments, the materials may have a viscosity of at least 1,000,000 cP, at least 5,000,000 cp in another embodiment, and at least 10,000,000 cP in yet another embodiment. Further, the material may be designed to possess sufficient viscidity and adhesive strength so that it can adhere to the mold wall during the manufacturing process, without moving, specifically, it may be spread or stuck to a surface of a graphite mold, and the mold may be vibrated or turned upside down without the material falling. Thus, for a given material, the adhesive strength should be greater than the weight of the material per given contact area (with the mold) of the material. Once such materials are adhered to the particular desired vertical surfaces, the remaining portions of rib cavities (corresponding to cutting portions for example) may be filled using a diamond/matrix powder mixture or encapsulated particles. A bit body material may be loaded into the rib material, and a softer matrix powder may be loaded thereon (particularly to serve as the backing of the gage surface). In a particular embodiment, a tough (and machinable) matrix material may be loaded from approximately 0.5 inches from the gage point to fill the mold. The entire mold contents may then be infiltrated using an infiltration binder (by heating the mold contents to a temperature over the melting point of the infiltration binder), as known in the art. Advantageously, embodiments of the present disclosure for at least one of the following. Prior art techniques have not allowed for use of two different matrix material to be mixed in a mold due to lack of controllability of the powder locations in the mold during assembly, particularly along curved surfaces. Bits of the present disclosure may include use of harder materials on the gage (for abrasive areas and horizontal applications) which may reduce the wearing of the gage matrix material, which in turn may decrease the loads on gage insert features and incidents of drilling under gage. Use of such harder materials at gage surfaces may be achieved while maintaining a slightly softer material on the primary cutting surfaces to prevent the use of brittle materials (leading to rib cracking and breaking). Furthermore, the use of pelletized grit on the gage has shown to offer improved diamond grit retention properties, thus improving gage wear resistance. Additionally, embodiments also provide for the use of a tougher material at a base portion of a rib, providing increased toughness to a rib, so that taller ribs (and greater rate of penetrations) may be achieved, without sacrificing durability. While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

A drill bit that includes a body having a lower end face for engaging a rock formation, the end face having a plurality of raised ribs extending from the face of the bit body and separated by a plurality of channels therebetween; and at least one of the plurality of ribs having a cutting portion of the at least one rib comprising a first diamond impregnated matrix material and at least a portion of a gage surface region thereof comprising a second diamond impregnated matrix material, the gage surface region backed by a third matrix material is disclosed.

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority from U.S. Provisional Application No. 60/773,290 filed Feb. 14, 2006. FIELD OF THE INVENTION [0002] This invention relates to a method of treating metal surfaces to enhance corrosion resistance and paint bonding characteristics and relates to trivalent chromium coatings for aluminum and aluminum alloys used in such processes, which are substantially or entirely free of hexavalent chromium. More particularly, this invention relates to an aqueous composition, suitable for use as a dry-in-place coating for metal, that comprises trivalent chromium cations, fluorometallate anions, their corresponding counterions, and other optional components, and methods for using same. BACKGROUND OF THE INVENTION [0003] It is generally known to treat the surfaces of metals, such as zinc, cadmium, or aluminum with aqueous hexavalent chromium solutions which contain chemicals that dissolve the surface of the metal and form insoluble films known as “chromate conversion coatings.” These coatings, which contain hexavalent chromium, are corrosion resistant and protect the metal from various elements which cause corrosion. In addition, it is known that hexavalent chromate conversion coatings generally have good paint bonding characteristics and, therefore, provide an excellent base for paint or other finishes. [0004] Although the aforementioned coatings enhance corrosion resistance and paint bonding properties, the coatings have a serious drawback, i.e., the toxic nature of the hexavalent chromium constituent. This is a serious problem from two viewpoints, one being the handling of the solution by operators and the other, the disposal of the used solution. Therefore, it is highly desirable to have coatings which are free of, or substantially free of, hexavalent chromium, but at the same time capable of imparting corrosion resistance and paint bonding properties which are comparable to those imparted by conventional hexavalent chromium coatings. [0005] Of particular interest is the use of hexavalent chromate conversion coatings on aircraft aluminum alloys due to the excellent corrosion resistance and the ability to serve as an effective base for paint. The baths used to develop these coatings contain hexavalent chromates, and it is the residual hexavalent chromates in the coating that is largely responsible for the high degree of corrosion inhibition. However, these same hexavalent chromates are toxic and their presence in waste water effluents is severely restricted. It would, therefore, be desirable to provide a composition for coating aluminum and its alloys, and for sealing of anodized aluminum, utilizing less hazardous chemicals that could serve as an alternative to the toxic hexavalent chromate coatings. There has been a significant unmet need in the coating industry to provide conversion coatings that contain little or no hexavalent chromium, but which still provide corrosion resistance and paint bonding that is comparable to the prior art hexavalent chromium containing conversion coatings. SUMMARY OF THE INVENTION [0006] It is therefore an object of this invention to provide a novel chromium-containing solution for treating aluminum, including anodized aluminum, wherein said solution contains no or substantially no hexavalent chromium, but provides performance comparable to the hexavalent chromium containing conversion coatings. [0007] It is another object of this invention to provide a composition for treating aluminum which contains chromium only in the trivalent oxidation state. Preferably, the composition contains substantially no zinc, meaning, no zinc other than trace amounts found in the raw materials or substrate to be coated. Most preferably no heavy metals, other than the trivalent chromium and those found in the fluorometallates, e.g. fluorozirconate, fluorotitanate and the like, are present in more than such trace amounts, that is substantially no other heavy metals. [0008] It is still another object of this invention to provide a trivalent chromium-containing solution wherein the trivalent chromium has little or no tendency to precipitate, preferably forming no Cr (III)-containing precipitate, during storage but reacts with metal substrates to form a trivalent chromium-containing coating on the metal substrate surface. That is, a composition wherein the Cr (III) is stable in solution. [0009] It is an object of the invention to provide compositions for treating a metal surface comprising a component of fluorometallate anions; a component of chromium(III) cations; and, optionally, one or more of the following components: a component of free fluoride ions; a component of surfactant molecules; a pH adjusting component and a viscosity increasing component. [0010] It is an object of this invention to provide a composition for coating or touching-up or both coating and touching-up a metal surface, the composition comprising water and: [0000] (A) from about 4.5 millimoles per kilogram to about 27 millimoles per kilogram of a component of fluorometallate anions and mixtures of fluorometallate anions, each of the anions comprising: (i) at least four fluorine atoms; and (ii) at least one atom of an element selected from the group consisting of titanium, zirconium, hafnium, silicon, aluminum, and boron, and, optionally, one or both of (iii) at least one ionizable hydrogen atom; and (iv) at least one oxygen atom; and (B) from about 3.8 g/l to about 46 g/l of trivalent chromium cations; the composition being substantially free of hexavalent chromium. Desirably, the fluorometallate anions are selected from the group consisting of fluorosilicate, fluorotitanate, and fluorozirconate anions, and mixtures thereof. [0015] In one embodiment, the fluorometallate anions include fluorozirconate anions in a concentration within a range from about 5.1 to about 24 mM/kg. In another embodiment, the liquid composition may comprise not more than 0.0.06% of dispersed silica and silicates. [0016] It is also an object of the invention to provide such a composition that further includes fluorinated alkyl ester surfactant molecules. Their concentration can be selected to fall within a range from about 0.070 to about 0.13 parts per thousand. [0017] In another embodiment, the fluorometallate anions include fluorozirconate anions, whose concentration is desirably within a range from about 4.5 to about 27 mM/kg; the concentration of chromium(III) cations may desirably be within a range from about 3.8 g/l to about 46 g/l; and the ratio of trivalent chromium to zirconium may desirably fall within the range of 12 to 22. Desirably, this composition further includes from about 0.070 to about 0.13 parts per thousand fluorinated alkyl ester surfactant molecules. [0018] In an alternative embodiment, a composition for coating or touching-up or both coating and touching-up a metal surface is made by mixing together a first mass of water and at least the following components: [0000] (A) a second mass of at least one water-soluble source of fluorometallate anions to provide in the composition from about 4.5 to about 27 mM/kg of the fluorometallate anions and mixtures thereof, each of the anions comprising: (i) at least four fluorine atoms; and (ii) at least one atom of an element selected from the group consisting of titanium, zirconium, hafnium, silicon, aluminum, and boron, and, optionally, one or both of (iii) at least one ionizable hydrogen atom; and (iv) at least one oxygen atom; and (B) a third mass of a component to provide the composition with from about 3.8 g/l to about 46 g/l of trivalent chromium cations. In one aspect of this embodiment, the composition may comprise not more than 0.06% of dispersed silica and silicates. [0023] It is also an object of the invention to provide a composition, wherein: the second mass comprises fluorozirconate anions in an amount that desirably corresponds to a concentration, in the composition, that is within a range from about 5.1 to about 24 mM/kg; and there is mixed into the composition a fourth mass of fluorinated alkyl ester surfactant molecules that desirably corresponds to a concentration, in the composition, that is within a range from about 0.070 to about 0.13 parts per thousand. [0024] It is also an object of the invention to provide compositions wherein the source or third mass of trivalent chromium cations is selected from the group consisting of acetates, nitrates, sulfates, fluorides and chlorides of chromium (III). [0025] Another aspect of the invention is a process for coating or touching-up or both coating and touching-up a surface, the surface comprising at least one area of bare metal, at least one area of coating over an underlying metal substrate, or both of at least one area of bare metal and at least one area of coating over an underlying metal substrate, the process comprising operations of: (I) covering the surface to be coated, touched-up, or both coated and touched-up with a layer of a liquid composition as described herein; and (II) drying the liquid layer formed in operation (I) to form a coated surface, and optionally applying a paint or sealant. [0028] Preferably, for reasons of economy and convenience, the coating of operation (I) is not rinsed prior to drying step (II). In one aspect of the process, the surface comprises at least one area of bare metal and at least one area of coating over an underlying metal substrate; and in operation (I), the liquid layer is formed over the at least one area of bare metal. [0029] The liquid composition used in operation (I) may comprise fluorozirconate anions in a concentration range from about 4.5 to about 27 mM/kg, preferably from about 5.1 to about 24 mM/kg; the concentration of chromium(III) ions is greater than 0 g/l and can be up to the solubility limit of chromium in the solution, desirably the concentration is at least 3.0 g/l and not more than 46 g/l. The composition can further include a surfactant comprising fluorinated alkyl ester molecules in a concentration that is within a range from about 0.070 to about 0.13 parts per thousand; and optionally a concentration of hydrofluoric acid is present within a range from about 0.70 to about 1.3 parts per thousand. [0030] In another embodiment of the process, the surface comprises at least one area of bare metal adjacent to at least one area of coating over an underlying metal substrate, the at least one area of coating over an underlying metal substrate comprising a first portion and a second portion, in operation (I), the liquid layer is formed over both the area of bare metal and at least the first portion of the adjacent area of coating over an underlying metal substrate; and the coating over an underlying metal substrate is selected from the group consisting of a phosphate conversion coating, a chromate conversion coating, and a conversion coating produced by contacting a surface consisting predominantly of iron, titanium, aluminum, magnesium and/or zinc and alloys thereof with an acidic treating solution comprising at least one of fluorosilicate, fluorotitanate, and fluorozirconate. [0031] It is still another object of this invention to provide an article of manufacture having at least one portion that comprises a metal surface coated as described herein, desirably an aluminum or aluminum alloy metal surface and/or an anodized aluminum surface. [0032] It is likewise an object of the invention to provide a coating that is dried-in-place on the metal surface, said coating comprising chromium in substantially only trivalent form and providing salt spray resistance of at least 96, 120, 144, 168, 192, 216, 240, 264, 288, 312, 336, 360, 408, 456, 480, 504 hours in corrosion testing according to ASTM B-117. Desirably surfaces coated according to the invention as described herein that are intended to be left unpainted will be selected from those coated surfaces that provide salt spray resistance of at least 336 hours. Coated surfaces that are intended to be subsequently painted or sealed may be selected from those coated surfaces that provide salt spray resistance of at least 96 hours. [0033] It is also an object of the invention to provide processes for treating a metal surface to form a protective coating, or for treating a metal surface on which a protective coating has previously been formed and remains in place, with its protective qualities intact, on one part of the surface but is totally or partially absent from, or is present only in a damaged condition over, one or more other parts of the surface, so that its protective value in these areas of at least partial damage or absence has been diminished. (Usually the absence or damage of the initial protective coating has been unintentional and has occurred as a result of such events as imperfectly uniform formation of the initial protective coating, mechanical damage of the initial protective coating, spotty exposure of the initially coated surface to solvents for the initial protective coating, or the like. The absence or damage of the initial protective coating may be intentional, however, as when holes are drilled in a coated surface, for example, or when untreated parts are attached to and therefore become part of a previously coated surface.) [0034] Particularly if the surface in question is large and the damaged or untreated area(s) are relatively small, it is often more economical to attempt to create or restore the full protective value of the original coating primarily in only the absent or damaged areas, without completely recoating the object. Such a process is generally known in the art, and will be briefly described herein, as “touching-up” the surface in question. This invention is particularly well suited to touching-up surfaces in which the original protective coating is a conversion coating initially formed on a primary metal surface, more particularly a primary metal surface consisting predominantly of iron, titanium, aluminum, magnesium and/or zinc and alloys thereof, this includes Galvalume and Galvaneal. One of skill in the art will understand “predominantly” as used herein to mean the predominant element is the one comprising the greatest amount by weight of the alloy. [0035] An alternative or concurrent object of this invention is to provide a process for protectively coating metal surfaces that were never previously coated. Other concurrent or alternative objects are to achieve at least as good protective qualities in the touched-up areas as in those parts of the touched-up surfaces where the initial protective coating is present and undamaged; to avoid any damage to any pre-existing protective coating from contacting it with the touching-up composition; and to provide an economical touching-up process. Other objects will be apparent to those skilled in the art from the description below. [0036] Except in the claims and the operating examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word “about” in describing the broadest scope of the invention. Practice within the numerical limits stated is generally preferred. Also, throughout this description, unless expressly stated to the contrary: percent, “parts of”, and ratio values are by weight; the term “polymer” includes “oligomer”, “copolymer”, “terpolymer”, and the like; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the invention implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred; description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description or of generation in situ by chemical reactions specified in the description, and does not necessarily preclude other chemical interactions among the constituents of a mixture once mixed; specification of materials in ionic form additionally implies the presence of sufficient counterions to produce electrical neutrality for the composition as a whole (any counterions thus implicitly specified should preferably be selected from among other constituents explicitly specified in ionic form, to the extent possible; otherwise such counterions may be freely selected, except for avoiding counterions that act adversely to the objects of the invention); the term “paint” includes all like materials that may be designated by more specialized terms such as primer, lacquer, enamel, varnish, shellac, topcoat, and the like; and the term “mole” and its variations may be applied to elemental, ionic, and any other chemical species defined by number and type of atoms present, as well as to compounds with well defined molecules. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0037] Corrosion resistant coatings, and compositions for depositing them, comprising hexavalent chromium alone or in combination with trivalent chromium, as well as coatings and baths comprising trivalent chromium that is oxidized to hexavalent chromium, in the bath or as part of the coating process are known. Heretofore, no trivalent chromium containing coating or coating bath has been developed that achieved adequate salt spray resistance for use on substrates that were not to be painted, unless hexavalent chromium was included in the coating. In particular, no trivalent chromium-containing coatings that have been dried-in-place on the substrate, as compared to trivalent chromium-containing coatings that are applied and then rinsed with water, have achieved salt spray resistance adequate for use on substrate that are to be left unpainted. Applicants have developed a hexavalent chromium-free, liquid composition that satisfies this unmet need. The composition is stable for more than 1000 hours, showing little or no precipitation of trivalent chromium compounds, and requires no post-rinsing of the substrate. [0038] One embodiment of the present invention provides a liquid composition that comprises, preferably consists essentially of, or more preferably consists of, water and: (A) a component of fluorometallate anions, each of said anions comprising, preferably consisting of: (i) at least four fluorine atoms; and (ii) at least one atom of an element selected from the group consisting of titanium, zirconium, hafnium, silicon, aluminum, and boron; and, optionally, one or both of (iii) at least one ionizable hydrogen atom; and (iv) at least one oxygen atom; (B) a component of chromium(III) cations; and, optionally, one or more of the following components: (C) a component of free fluoride ions that are not part of any of immediately previously recited components (A) through (B); (D) a component of surfactant molecules that are not part of any of immediately previously recited components (A) through (C); (E) a pH adjusting component that is not part of any of the immediately previously recited components (A) through (D); and (F) a viscosity increasing component that is not part of any of the immediately previously recited components (A) through (E). [0049] It should be understood that alternatively, the components listed need not necessarily all be provided by separate chemicals. For example, HF may provide pH adjustment as well as free fluoride ions. [0050] It has been found that excellent coating and/or touching-up quality, particularly for corrosion resistance on previously untreated areas and corrosion resistance in combination with a conversion coating, can be achieved by: (I) covering the areas to be touched-up with a layer of the above described composition of the invention; and subsequently (II) drying into place over the surface the liquid layer formed in step (I); the coated surfaces by subsequently be given an optional coating of paint or sealant. [0054] The compositions of the invention have been developed as hexavalent chromium-free. Although not preferred, formulations according to the invention can be made including hexavalent chromium. Compositions according to the invention desirably contain less than 0.04, 0.02, 0.01, 0.001, 0.0001, 0.00001, 0.000001 percent by weight of hexavalent chromium, most preferably essentially no hexavalent chromium. The amount of hexavalent chromium present in the compositions of the invention is desirably minimized. Preferably only traces of hexavalent chromium are present in the composition and the deposited conversion coating, in amounts such as are found as trace elements in the raw materials used or in the substrates treated. Most preferably no hexavalent chromium is present. [0055] It is known in the prior art to oxidize some of the trivalent chromium in a coating to form hexavalent chromium, see U.S. Pat. No. 5,304,257. In the present invention, it is desirable that the coatings formed by compositions, as dried-in-place, according to the invention contain hexavalent chromium only in the amounts as recited in the immediately preceding paragraph, that is, little or no hexavalent chromium. It will be understood by those of skill in the art that the invention includes coatings that as dried-in-place contain no hexavalent chromium but which may, due to subsequent exposure to weathering or other treatments, contain hexavalent chromium resulting from oxidation of the trivalent chromium in the coating. [0056] In a preferred embodiment of the invention, the composition and the resulting dried-in-place coating are substantially free, desirably essentially free, of hexavalent chromium. More preferably, any hexavalent chromium is present in trace amounts or less, and most preferably the compositions contain no hexavalent chromium. [0057] Various embodiments of the invention include processes for treating surfaces as described above, optionally in combination with other process steps that may be conventional per se, such as precleaning, rinsing, and subsequent further protective coatings over those formed according to the invention, compositions useful for treating surfaces as described above, and articles of manufacture including surfaces treated according to a process of the invention. [0058] Independently of the concentration of Component (A), the fluorometallate anions preferably are fluorosilicate (i.e., SiF 6 −2 ), fluorotitanate (i.e., TiF 6 −2 ) and/or fluorozirconate (i.e., ZrF 6 −2 ), more preferably fluorotitanate or fluorozirconate, most preferably fluorozirconate. [0059] In general a working composition for use in a process according to this invention desirably has a concentration of at least, with increasing preference in the order given, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3 millimoles of fluorometallate anions, component (A), per kilogram of total working composition, this unit of concentration being freely applicable hereinafter to any other constituent as well as to fluorometallate anions and being hereinafter usually abbreviated as “mM/kg”. Independently, in a working composition, the concentration of fluorometallate ions preferably, at least for economy, is not more than, with increasing preference in the order given, 27.0, 26.0, 25.0, 24.0, 23.0, 22.0, 21.0, 20.0, 19.0, 18.5, 18.0, 17.5, 17.0, 16.5, 16.0, 15.5, 15.0, 14.5, 14.0, 13.5, 13.0, 12.5, 12.0, 11.5, 11.0, 10.9, 10.8, 10.7 mM/kg. [0060] If the working composition is intended for use in a process in which at least two treatments according to the invention will be applied to the substrate, the concentration of fluorometallate anions still more preferably can be not more than, with increasing preference in the order given, 15, 12, 10, 8.0, 7.0, 6.5, 6.0, 5.5, or 5.1 mM/kg. In the event that only a single treatment with a composition according to the invention is desired, for maximum corrosion protection, the concentration of fluorometallate anions preferably is at least, with increasing preference in the order given, 9.0, 9.5, 9.7, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, 21.0, 22.0, 23.0, or 24.0 mM/kg. [0061] Desirably the cation for the fluorometallate anion selected from ions of Group IA elements, or ammonium ions. Preferably the cation is K or H, most preferably H. [0062] Component (B) as defined above is to be understood as including one or more of the following sources of trivalent chromium cations: acetates, nitrates, sulfates, fluorides, and chlorides of chromium(III), and the like. In a preferred embodiment, Component (B) comprises, preferably consists essentially of, most preferably consists of trivalent chromium fluoride. The total concentration of trivalent chromium cations in a working composition according to the invention is preferably at least, with increasing preference in the order given, 3.8, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.3, 14.5, 14.7, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 g/l, and independently, primarily for reasons of economy, is preferably not more than, with increasing preference in the order given, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36 g/l. [0063] A component of free fluoride ions (C) may optionally be provided, which may or may not be part of any of immediately previously recited components (A) through (B). This component may be supplied to the composition by hydrofluoric acid or any of its partially or completely neutralized salts that are sufficiently water soluble. At least for economy, component (C) is preferably supplied by aqueous hydrofluoric acid, and independently preferably is present in a concentration that is at least, with increasing preference in the order given, 0.10, 0.30, 0.50, 0.60, 0.70, 0.80, or 0.90 parts per thousand of its stoichiometric equivalent as HF. Independently, in a working composition to be used in a process according to the invention, the concentration of component (C), measured as its stoichiometric equivalent as HF, preferably is not more than, with increasing preference in the order given, 10, 8.0, 6.0, 4.0, 3.0, 2.0, 1.5, 1.3, or 1.1 parts per thousand. Suitable sources of free fluoride ions are known to those of skill in the art. Preferably, the source of (C) is HF. [0064] Component (D), if used, is chosen from anionic surfactants, such as salts of carboxylic acids, alkylsulphonates, alkyl-substituted phenylsulphonates; nonionic surfactants, such as alkyl-substituted diphenylacetylenic alcohols and nonylphenol polyoxyethylenes; and cationic surfactants such as alkylammonium salts; all of these may and preferably do contain fluorine atoms bonded directly to carbon atoms in their molecules. Each molecule of a surfactant used preferably contains a hydrophobe portion that (i) is bonded by a continuous chain and/or ring of covalent bonds; (ii) contains a number of carbon atoms that is at least, with increasing preference in the order given, 10, 12, 14, or 16 and independently preferably is not more than, with increasing preference in the order given, 30, 26, 22, or 20; and (iii) contains no other atoms except hydrogen, halogen, and ether-bonded oxygen atoms. Component (D) is most preferably a non-ionic fluorosurfactant, such materials are known in the art and commercially available under the Zonyl® trade name from E.I. du Pont de Nemours and Company. [0065] A working composition according to the invention may contain, with increasing preference in the order given, at least 0.010, 0.030, 0.050, 0.070, 0.080, 0.090, or 0.100 parts per thousand of component (D) and independently preferably, primarily for reasons of economy, contains not more than, with increasing preference in the order given, 5.0, 2.5, 1.30, 0.80, 0.60, 0.40, 0.30, 0.20, 0.18, 0.15, 0.13, or 0.11 parts per thousand of component (D). [0066] The pH of a composition used according to the invention preferably is at least, with increasing preference in the order given, 2.10, 2.30, 2.50, 2.70, 2.90, 3.0, 3.10, 3.20, 3.30, 3.40, 3.50, 3.55, or 3.60 and independently preferably is not more than, with increasing preference in the order given, 5.0, 4.95, 4.90, 4.80, 4.70, 4.60, 4.50, 4.40, 4.30, 4.20, 4.10, 4.00, 3.90, 3.80, or 3.70. A pH adjusting component (E), which may or may not be part of any of the immediately previously recited components (A) through (D) can be added to the composition in an amount sufficient to produce a pH in the above-recited range, as necessary. A pH adjusting component may be any acid or a base, known in the art which does not interfere with the objects of the invention. In one embodiment, the pH adjuster is an acid, desirably HF, which also provides free fluoride ion (C). In another embodiment, the pH adjusting component comprises a base, and desirably is ammonium hydroxide. [0067] Dilute compositions within these preferred ranges, that include the necessary active ingredients (A) through (B) only, may have inadequate viscosity to be self-supporting in the desired thickness for touching-up areas that can not be placed in a substantially horizontal position during treatment and drying; if so, one of the materials known in the art, such as natural gums, synthetic polymers, colloidal solids, or the like should be used as optional component (F), as is generally known in the art, unless sufficient viscosity is provided by one or more of other optional components of the composition. If the characteristic treatment composition is to be applied in a process according to the invention by use of a saturated felt or like material, component (F) is rarely needed and usually is preferably omitted, because most viscosity increasing agents are susceptible to being at least partially filtered out of the treatment composition by applicators of this type. [0068] A working composition according to the invention may be applied to a metal workpiece and dried thereon by any convenient method, several of which will be readily apparent to those skilled in the art. For example, coating the metal with a liquid film may be accomplished by immersing the surface in a container of the liquid composition, spraying the composition on the surface, coating the surface by passing it between upper and lower rollers with the lower roller immersed in a container of the liquid composition, contact with a brush or felt saturated with the liquid treatment composition, and the like, or by a mixture of methods. Excessive amounts of the liquid composition that might otherwise remain on the surface prior to drying may be removed before drying by any convenient method, such as drainage under the influence of gravity, passing between rolls, and the like. [0069] A particularly advantageous method of application of the treatment liquid in a process according to this invention makes use of an applicator as disclosed in U.S. Pat. Nos. 5,702,759 and 6,010263 to White et al., the entire disclosure of which, except for any part that may be inconsistent with any explicit statement herein, is hereby incorporated herein by reference. [0070] The temperature during application of the liquid composition may be any temperature within the liquid range of the composition, although for convenience and economy in application, normal room temperature, i.e., from 20-27° C. is usually preferred. [0071] Application of compositions of the instant invention provide improved adhesive bonding to subsequently applied protective layers, such as paints, lacquers and other resin based coatings. [0072] Preferably the amount of composition applied in a process according to this invention is chosen so as to result, after drying into place, in at least as good corrosion resistance for the parts of the surface treated according to the invention as in the parts of the same surface where the initial protective coating is present and a process according to the invention has not been applied. Ordinarily, for most common protective chromate conversion coatings as initial protective coatings, such protection will be achieved if the total add-on mass (after drying) of the coating applied in a process according to the invention is at least, with increasing preference in the order given, 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, or 0.060 grams per square meter of surface coated (hereinafter usually abbreviated as “g/m 2 ”). Independently, at least equal corrosion resistance ordinarily will be achieved even if the add-on mass is not, and therefore for reasons of economy the add-on mass preferably is not greater than, with increasing preference in the order given, 1.00, 0.70, 0.50, 0.30, 0.20, 0.15, 0.10, 0.090, 0.085, 0.080, or 0.075 g/m 2 [0073] The add-on mass of the protective film formed by a process according to the invention may be conveniently monitored and controlled by measuring the add-on weight or mass of the metal atoms in the anions of component (A) as defined above, or of chromium, except in the unusual instances when the initial protective coating and/or the underlying metal substrate contains the same metal element(s). The amount of these metal atoms may be measured by any of several conventional analytical techniques known to those skilled in the art. The most reliable measurements generally involve dissolving the coating from a known area of coated substrate and determining the content of the metal of interest in the resulting solution. The total add-on mass can then be calculated from the known relationship between the amount of the metal in component (A) and the total mass of the part of the total composition that remains after drying. However, this method is often impractical for use with this invention, because the area touched-up is not always precisely defined. A more practical alternative is generally provided by small area X-ray spectrographs that, after conventional calibration, directly measure the amount(s) per unit area of individual metallic element(s) present in a coating, free from almost all interferences except the same elements present in other coatings on, or in a thin layer near the surface of, the underlying metal surface itself. [0074] The effectiveness of a treatment according to the invention appears to be affected by the total amounts of the active ingredients that are dried-in-place on each unit area of the treated surface, and on the nature of the active ingredients and their ratios to one another, rather than on the concentration of the acidic aqueous composition used. The speed of drying has not been observed to have any technical effect on the invention, although it may well be important for economic reasons. If practical in view of the size of the object treated and the size of the areas of the object to be treated, drying may be speeded by placement of the surface to be treated, either before or after application to the surface of a liquid composition in a process according to the invention, in an oven, use of radiative or microwave heating, or the like. If speed of treatment is desired, but placing the entire object in an oven is inconvenient, a portable source of hot air or radiation may be used in the touched-up area(s) only. In either instance, heating the surface before treatment is preferred over heating after treatment when practical, and prewarming temperatures up to at least 65° C. may be satisfactorily used. If ample time is available at acceptable economic cost, a liquid film applied according to this invention often may simply be allowed to dry spontaneously in the ambient atmosphere with equally good results insofar as the protective quality of the coating is concerned. Suitable methods for each circumstance will be readily apparent to those skilled in the art. [0075] Preferably, the surface to be treated according to the invention is first cleaned of any contaminants, particularly organic contaminants and foreign metal fines and/or inclusions. Such cleaning may be accomplished by methods known to those skilled in the art and adapted to the particular type of substrate to be treated. For example, for galvanized steel surfaces, the substrate is most preferably cleaned with a conventional hot alkaline cleaner, then rinsed with hot water and dried. For aluminum, the surface to be treated most preferably is first contacted with a conventional hot alkaline cleaner, then rinsed in hot water, then, optionally, contacted with a neutralizing acid rinse and/or deoxidized, before being contacted with an acid aqueous composition as described above. Ordinarily, cleaning methods suitable for the underlying metals will also be satisfactory for any part of the initial protective coating that is also coated in a process according to the invention, but care should be taken to choose a cleaning method and composition that do not themselves damage the protective qualities of the initial protective coating in areas that are not to be touched-up. If the initial protective coating is thick enough, the surface can be satisfactorily cleaned by physically abrading, as with sandpaper or another abrasive, the area(s) to be touched-up and any desired overlap zone where the initial protective coating is still in place around the damaged areas to be touched-up. The swarf may then be removed by blowing, brushing, rinsing, or with attachment to a cleaning tool, such as a moist cloth. It has been found that, when dry abrasion is used as the last preparatory cleaning method, the corrosion resistance of the coating usually will be less than optimal and the coating will appear smutty. However, dry abrasion followed by wiping, e.g. with a clean cloth, or rinsing is a satisfactory and often preferred cleaning method. One indication that the surface is sufficiently clean is that a film of water sprayed on the surface will dry without beading. A preferred process is abrasion using a Scotch-Brite™ pad, commercially available from 3M Corporation, or similar abrasive material, followed by wiping with a clean “Chem Wipe”, commercially available from Henkel Corporation, followed by application of the invention. [0076] After the preparatory cleaning, the surface may be dried by absorption of the cleaning fluid, evaporation, or any suitable method known to those skilled in the art. Corrosion resistance is usually less than optimal when there is a delay between the preparatory cleaning, or cleaning and drying, and the coating of the surface. The time between cleaning, or cleaning and drying, and coating the surface should be no more than, in increasing order of preference, 48, 24, 12, 6.0, 5.0, 4.0, 3.0, 2.0, 1.0, 0.50, 0.25, or 0.1 hours. [0077] Usually, it is preferable, as a precaution during a touch-up process according to the invention, to apply the composition used for touching-up not only to obviously bare metal or obviously damaged areas of the initial protective coating, but also over a transition or overlap zone of apparently undamaged initial protective coating adjacent to such areas that obviously need touching-up. With increasing preference in the order given, such a transition zone has a width that is at least 0.2, 0.5, 0.7, 1.0, 1.5, or 2.0 millimeters and independently preferably, primarily for reasons of economy, is not more than, with increasing preference in the order given, 25, 20, 15, 10, 8.0, 6.0, 5.0, or 3.0 millimeters. [0078] Virtually any kind of initial protective coating can be touched-up effectively for many purposes by a process according to this invention. In particular, but without limitation, conversion coatings produced on underlying metal according to the teachings of any one of the following U.S. Patents, the disclosures of all of which, except to any extent that they may be inconsistent with any explicit statement herein, are hereby incorporated herein by reference, may be effectively touched-up by a process according to this invention: U.S. Pat. No. 5,769,667 of Jun. 23, 1998 to Dolan; U.S. Pat. No. 5,700,334 of Dec. 23, 1997 to Ishii et at; U.S. Pat. No. 5,645,650 of Jul. 8, 1997 to Ishizaki et al.; U.S. Pat. No. 5,683,816 of Nov. 4, 1997 to Goodreau; U.S. Pat. No. 5,595,611 of Jan. 21, 1997 to Boulos et al.; U.S. Pat. No. 5,551,994 of Sep. 3, 1996 to Schriever; U.S. Pat. No. 5,534,082 of Jul. 9, 1996 to Dollman et al.; U.S. Pat. No. 5,507,084 of Apr. 16, 1996 to Ogino et al.; U.S. Pat. No. 5,498,759 of Mar. 12, 1996 to Nakada et al.; U.S. Pat. No. 5,498,300 of Mar. 12, 1996 to Aoki et al.; U.S. Pat. No. 5,487,949 of Jan. 30, 1996 to Schriever, U.S. Pat. No. 5,472,524 of Dec. 5, 1995; U.S. Pat. No. 5,472,522 of Dec. 5, 1995 to Kawaguchi et at; U.S. Pat. No. 5,452,884 of Oct. 3, 1995; U.S. Pat. No. 5,451,271 of Sep. 19, 1995 to Yoshida et al.; U.S. Pat. No. 5,449,415 of Sep. 19, 1995 to Dolan; U.S. Pat. No. 5,449,414 of Sep. 12, 1995 to Dolan; U.S. Pat. No. 5,427,632 of Jun. 27, 1995 to Dolan; U.S. Pat. No. 5,415,687 of May 16, 1995 to Schriever; U.S. Pat. No. 5,411,606 of May 2, 1995 to Schriever; U.S. Pat. No. 5,399,209 of Mar. 21, 1995 to Suda et al.; U.S. Pat. No. 5,395,655 of Mar. 7, 1995 to Kazuyuki et al.; U.S. Pat. No. 5,391,239 of Feb. 21, 1995 to Boulos; U.S. Pat. No. 5,378,392 of Jan. 3, 1995 to Miller et al.; U.S. Pat. No. 5,366,567 of Nov. 22, 1994 to Ogino et al.; U.S. Pat. No. 5,356,490 of Oct. 18, 1994 to Dolan et al.; U.S. Pat. No. 5,342,556 of Aug. 30, 1994 to Dolan; U.S. Pat. No. 5,318,640 of Jun. 7, 1994 to Ishii et al.; U.S. Pat. No. 5,298,092 of Mar. 29, 1994 to Schriever; U.S. Pat. No. 5,281,282 of Jan. 25, 1994 to Dolan et al.; U.S. Pat. No. 5,268,042 of Dec. 7, 1993 to Carlson; U.S. Pat. No. 5,261,973 of Nov. 16, 1993 to Sienkowski et al.; U.S. Pat. No. 5,242,714 of Sep. 7, 1993 to Steele et al.; U.S. Pat. No. 5,143,562 of Sep. 1, 1992 to Boulos; U.S. Pat. No. 5,141,575 of Aug. 25, 1992 to Yoshitake et al.; U.S. Pat. No. 5,125,989 of Jun. 30, 1992 to Hallman; U.S. Pat. No. 5,091,023 of Feb. 25, 1992 to Saeki et al.; U.S. Pat. No. 5,089,064 of Feb. 18, 1992 to Reghi; U.S. Pat. No. 5,082,511 of Jun. 21, 1992 to Farina et al.; U.S. Pat. No. 5,073,196 of Dec. 17, 1991; U.S. Pat. No. 5,045,130 of Sep. 3, 1991 to Gosset et al.; U.S. Pat. No. 5,000,799 of Mar. 19, 1991 to Miyawaki; U.S. Pat. No. 4,992,196 of Feb. 13, 1991 to Hallman. [0079] A process according to this invention is particularly advantageously applied to touching-up a surface in which the undamaged parts are protected by a coating selected from the group consisting of a phosphate conversion coating, a chromate conversion coating, and a conversion coating produced by contacting a predominantly aluminiferous or a predominantly zinciferous surface with an acidic treating solution comprising at least one of fluorosilicate, fluorotitanate, and fluorozirconate. [0080] In addition, of course, metal surfaces with any other type of previously applied protective coating or without any previous deliberately applied coating can be coated in a process according to the invention. [0081] The practice of this invention may be further appreciated by consideration of the following, non-limiting, working examples. EXAMPLES Example 1 [0082] Three compositions containing different concentrations of trivalent chromium were made according to Table 1. An amount of chromium (III) fluoride, as recited in Table 1 for each respective formula, was added to 160° F. water and mixed until dissolved completely. The solution was cooled to room temperature and fluorozirconic acid added. The pH was 2.7 and was adjusted to pH 4 by addition of ammonium hydroxide. [0000] TABLE 1 Amount (g/liter) Component Formula A Formula B Formula C CrF 3 —4H 2 O 15.5 31.0 46.5 Fluorozirconic acid, 45% 2.22 4.44 6.66 Distilled water Remainder Remainder Remainder [0083] Two commercially available, 2024 T3 bare aluminum panels for each formula were abraded with a Scotch-Brite™ pad until surface oxidation was removed. A total of six panels were treated, two for each composition in Table 1. Each panel received two coats (one applied horizontally and one applied vertically) with a 50% overlap of parallel applications lines, meaning all surfaces received at least two layers of treatment. The panels were allowed to dry without rinsing and cured for 3 days at ambient temperature and humidity. All panels were exposed to 168 hours salt spray testing according to ASTM B117. Formula A panels pitted at 75 pits for each 3×6 inch panel. Formula B had one panel with no pits and one panel with 3 pits. Formula C showed no pitting but showed black and dark grey staining. Benchmarking [0084] Formula A, as modified in Table 1A, was compared for performance in a dry-in-place application with two products according to the prior art. [0085] Formula 1, a hexavalent chromium-containing composition formulated for dry-in-place use; Formula 2, a hexavalent chromium-free, trivalent chromium-containing composition useful for coating operations where the substrate is rinsed after contact with the coating composition, both commercially available from Henkel Corporation; and Formula A were compared for performance as dried-in-place coatings. [0000] TABLE 1A Amount (g/liter) Component Formula 1 Formula A Formula 2 Chromic Acid Flake 8.56 CrF 3 —4H 2 O 15.5  CrOHSO 4 35% 4.45 Phosphoric Acid 75% 1.00 Thickener 0.94 0.94 Surfactant 0.10 0.10 Fluorozirconic Acid, 40% 2.22 5.48 Fluorozirconic Acid, 45% 2.22 Liquid Caustic Potash 45% 3.62 Distilled water Remainder Remainder Remainder [0086] The coating and salt spray testing procedure of Example 1 was used for all three compositions. In the ASTM salt spray test, Formula A performed better than Formula 2, the trivalent chromium-containing formula useful for coat-then-rinse applications, but not as well as Formula 1, the hexavalent chromium-containing composition formulated for dry-in-place use. Example 2 [0087] Formula B from Example 1 was applied to 6 additional panels that had been abraded with a Scotch-Brite™ pad until surface oxidation was removed. Formula B was applied to the panels as shown in Table 2, with coats 1 and 3 applied vertically and coat 2 applied horizontally, that is transverse to the direction of application of coats 1 and 3. The treated panels were exposed to salt spray testing for 336 hours according to ASTM B117. The results are recited in Table 2: [0000] TABLE 2 Number Panel Amount of of Results Number Coating Coats 336 hours Salt Spray 1 Heavy 1 No pits 2 Light 1 No pits 3 Heavy 2 No pits 4 Light 2 No pits; rundown from salt spray markings 5 Heavy 3 No pits; rundown from salt spray markings 6 Light 3 No pits; rundown from salt spray markings Example 3 [0088] A composition according to the invention was made as recited in Table 3: [0000] TABLE 3 Component Amount (g) Distilled water 3854.08 CrF 3 -4H 2 O 124.00 Fluorozirconic acid, 45% 17.76 Total 3995.84 The composition was pH adjusted to pH 4 by addition of ammonium hydroxide. [0089] Panels of the following materials were obtained from aerospace supplier, Kaiser: 2024 aluminum, 6061 aluminum, 7075 aluminum. Five panels of each material were abraded with a Scotch-Brite™ pad until surface oxidation was removed. The panels were treated with the composition of Table 3, which had been prepared according to the method recited in Example 1. Each panel received two coats with a 50% overlap, meaning all surfaces received at least two layers of treatment, one in a vertical direction and one in a horizontal direction. All panels were exposed to salt spray testing according to ASTM B117. All five 2024 aluminum panels passed the 336 hours salt spray test with no pitting. All five panels of the 6061 aluminum passed the 336 hours salt spray test with no pitting. For the 7075 aluminum, three panels passed 336 hours salt spray with no pits. Two panels had minor edge pitting, but still passed the corrosion test. Example 4 [0090] A composition according to the invention was made as recited in Example 3. Panels of the following materials were obtained from aerospace supplier, Kaiser: 2024-T3 aluminum, 6061 aluminum, and 7075 aluminum, as well as 2024-T3 Clad and 7075 Clad aluminum. The panels were treated according to the procedure of Example 3. The results of ASTM B117 salt spray testing for these panels is shown in Table 4. [0000] TABLE 4 336 Hours Salt Spray (ASTM B117) Test Panel Number Alloy Material and Cladding 1 2 3 2024-T3 Clad 0 pits 0 pits 0 pits 7075 Clad 0 pits 0 pits 0 pits 2024-T3 Bare 0 pits 0 pits 0 pits 6061 Bare 0 pits 0 pits 0 pits 7075 Bare 0 pits 0 pits 0 pits Example 5 [0091] A composition according to the invention was made as recited in Example 3. Two panels of 2024-T3 aluminum were coated with Alodine® 1600, a hexavalent chromium containing conversion coating commercially available from Henkel Corporation, according to Henkel Technical Process Bulletin No. 236149. Two different panels of 2024-T3 aluminum were coated with Formula 2, a trivalent chromium-containing conversion coating commercially available from Henkel Corporation, and rinsed, according to Henkel Technical Process Bulletin No. 239583. The panels were allowed to cure for the time period recited in Table 5, and were then touched-up with the composition according to Example 3. The panels received two coats with a 50% overlap, meaning all surfaces received at least two layers of treatment, one in a vertical direction and one in a horizontal direction. All panels were then exposed to salt spray testing according to ASTM B117, with results as shown in Table 5. [0000] TABLE 5 336 hour Salt Spray Resistance after Touch-up over existing coating Time between Panel Number original coating and Alloy Material Existing Coating 1 2 touch-up application 2024-T3 Bare Alodine ® 1600 0 pits 0 pits 2 hours 2024-T3 Bare Formula 2 0 pits 0 pits 2 hours 2024-T3 Bare Alodine ® 1600 0 pits 0 pits 2 weeks 2024-T3 Bare Formula 2 0 pits 0 pits 2 weeks Example 6 [0092] A composition according to the invention was made as recited in Example 3. Panels of 2024-T3 aluminum were treated according to the procedure of Example 3, but the type of abrasive material was varied as was the method of mechanical abrasion. Green Scotch Brite™ Pads are described by the manufacturer as Scotch Brite™ General Purpose Scouring Pad No. 96; yellow Scotch Brite™ Pads are described by the manufacturer as Scotch Brite™ Clear Blend Prep Scuff N. 051131-07745. Electrical orbital sanders were those typically used in the aerospace industry as is known by those of skill in the art. All panels were abraded for 3 minutes and wiped to remove debris, prior to coating with the composition of Example 3. All panels were then exposed to salt spray testing according to ASTM B117, with results as shown in Table 6. [0000] TABLE 6 336 hour Salt Spray Resistance Unaffected by varying Scotch Brite ™ Method Type of Scotch Brite ™ Method of Mechanical Panel Number Alloy Material Pad Used Abrasion 1 2 2024-T3 Bare Green Electric Orbital Sander 0 pits 0 pits 2024-T3 Bare Yellow Electric Orbital Sander 0 pits 0 pits 2024-T3 Bare Green Manually Hand Sand 0 pits 0 pits 2024-T3 Bare Yellow Manually Hand Sand 0 pits 0 pits Example 7 [0093] A composition according to the invention was made and applied to panels of 6061 aluminum as recited in Example 3. Each panel was given one or two coats of the composition and then allowed to cure as recited in Table 7. The resistivity of the coated surface was measured in milliohms according to Mil-DTL-81706B with the following results: [0000] TABLE 7 Electrical Resistance on 6061 Bare per Military Specification: Mil-DTL-81706B Resistivity Number of coats Cure Time (days) (milliohms) 1 1 1.19 2 1 0.45 1 3 1.3 2 3 0.9

Corrosion resistant coatings are formed on aluminum by contacting with aqueous solutions containing trivalent chromium ions and fluorometallate ions, the solutions being substantially free of hexavalent chromium. Trivalent chromium films formed on the aluminum surface when tested in 5% NaCl salt spray chamber showed corrosion resistance in excess of 168 hours. Trivalent chromium coated aluminum also serves as an effective base for paint primers.

BACKGROUND OF THE INVENTION The present invention relates to an apparatus used for the storage of small items and, more particularly, but not by way of limitation, to an apparatus removably mounted to the ceiling of an automobile roof in a position above the heads of a vehicle's occupants across the ceiling from the driver's side to the passenger's side in order to provide storage for items normally carried within an automobile such as cassette tapes, compact discs, gloves, sunglasses, maps, nasal tissue, garage opener, mail, first aid kit, loose change, and/or hand towels. In today's society, automobiles are more like second homes than a means of transportation. As such, people routinely carry large amounts of personal belongings within their automobiles. Unfortunately, storage space for smaller items which are easily lost is extremely limited in most of today's automobiles. Thus, small items such as cassette tapes, compact discs, maps, sunglasses, and gloves are left lying about the automobile where they be lost within the seats or out the door or they find their way to the floorboards where they are ruined under an occupant's feet. Additionally, small personal items left laying about an automobile create a dangerous situation if the vehicle's driver wishes to find a particular object while driving. That is, if the item is not readily available, a driver may temporarily avert his/her eyes from the road in an attempt to locate the desired item. Seeking to locate an object within an automobile by averting one's eyes from the road produces an extremely dangerous situation because failure to pay full attention to the road is likely to be the cause of an accident resulting in the injury of the driver, innocent third parties, or both. The above situation is clearly exemplified when the item in the car is a cassette tape or compact disc. With the proliferation of radios which are outfitted with cassette tape players or compact disc players, the trend is to possess a large personal music collection readily available in one's automobile. Normally, these collections consist of cassette tapes or compact discs either spread throughout an automobile's interior or placed in a cassette tape or compact disc carrying case which is located on one of the car's seats. Thus, a vehicle operator desiring to listen to his/her favorite song must either randomly grab tapes or CD's stuck in various the crevices in the car's interior or open the carrying case placed on one of the car's seats and search through the tapes or CD's held within until the desired one is found. In either case, the driver's will take his/her eyes off the road for what may amount to an extended period of time just to find the desired tape or CD. Such a lack of attention to the road is unacceptable when safe driving is considered. Failure to pay proper attention while driving is a large cause of automobile accidents, and searching for items in a car such as cassette tapes or CD's certainly encourages a driver to avert his/her eyes from the road. The present invention, therefore, provides an apparatus that overcomes the lack of storage within an automobile which causes small items to be ruined or lost and further creates the dangerous driver condition of failing to pay full attention to the road provoked when a small object which is not readily accessible must be located during vehicle operation. SUMMARY OF THE INVENTION The present invention is a car storage system which may be mounted to an automobile's ceiling in a position above the head of a vehicle operator across from the driver's side to the passenger's side. The car storage system of the present invention comprises an adjustable support member equipped with pivotable flanges which are designed to fit behind the molding which surrounds the edges of the ceilings in most automobiles. The car storage system of the present invention further comprises a storage member, comprised of a plurality of storage compartments, which is removably connected to the support member. To mount the car storage system of the present invention within an automobile, one of the pivotable flanges is positioned at an angle which will allow it to fit behind the ceiling molding, and then its edge is inserted behind the molding. Second, the support member is adjusted to the appropriate ceiling width. Finally, the flange opposite from the inserted flange is positioned at an angle which will also allow it to fit behind the ceiling molding, and then its edge is inserted behind the molding. Each flange edge is forced behind the ceiling molding to suspend the support member along the ceiling of the automobile from the driver's side to the passenger's side. Although the support member may be positioned at any point along the ceiling molding, it is normally desirable to place the support member slightly forward and above of the head of the vehicle operator. Finally, after the support member is in place, the storage member is connected to the support member and locked securely in position to complete the assembly of the car storage system of the present invention. Thus, the present invention provides a car storage system which furnishes a plurality of individual storage compartments which are easily accessible to a vehicle operator. In use, the plurality of storage compartments which reside above the head of the vehicle operator may be filled with various items such as cassette tapes, compact discs, gloves, maps, sunglasses, hand towels, garage door openers, mail, loose change, and/or nasal tissue for easy access by the vehicle operator. With regard to cassette tapes, a vehicle operator may place all his/her favorite tapes in the storage compartments. By placing the tapes in the storage compartments, the vehicle operator has completely eliminated either having the tapes randomly spread throughout the automobile's interior or the necessity of having a separate carrying case placed on one of the vehicle's seats. If the vehicle operator wishes to retrieve a tape, he/she merely reaches up and pulls a tape which may then be placed in the tape player. A vehicle operator that places his/her tape in a systematic order will not even have to glance at the tape before it is inserted into the cassette player. The car storage system of the present invention, accordingly, eliminates the need of a vehicle operator to avert his/her eyes from the road during vehicle operation to find small items in the automobile. Any item may be retrieved without the necessity of having to stop paying attention to the road. The item may merely be pulled from the correct storage compartment using only touch. It is, therefore, an object of the present invention to provide a car storage system which allows small items normally carried within an automobile to be stored in an easily accessible location. It is another object of the present invention to provide a car storage system which may be mounted away from a vehicle's occupants so that seat space is not limited. It is a further object of the present invention to provide a car storage system which is size adjustable in order to allow it to fit in a variety of automobiles. It is still another object of the present invention to provide a car storage system which has a plurality of storage compartments which are accessible to the vehicle operator without necessitating the vehicle operator having to avert his/her eyes from the road. It is even another object of the present invention to provide a car storage system with a storage member which performs as a carrying case once detached from the support member. It is even a further object of the present invention to provide a car storage system which keeps cassette tapes and/or CD's out of direct sunlight. Still other features and advantages of the present invention will become evident to those skilled in the art in light of the following. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing the car storage system according to the preferred embodiment of the present invention mounted along the ceiling of a car roof. FIG. 2 is a side view showing the car storage system according to the preferred embodiment of the present invention mounted along the ceiling of a car roof. FIG. 3 is a front view showing the support member of the car storage system according to the preferred embodiment of the present invention. FIG. 4 is a bottom view showing the support member of the car storage system according to the preferred embodiment of the present invention. FIG. 5 is a partial bottom view of the support member showing the locking mechanism which makes the support member adjustable. FIG. 6 is a front view showing the storage member of the car storage system according to the preferred embodiment of the present invention. FIG. 7 is a bottom view showing the storage member of the car system storage according to the preferred embodiment of the present invention. FIG. 8 is a cross-sectional side view showing individual storage compartments of the storage member of the present invention. FIG. 9 is a perspective view showing the mounting of the storage member to the support member to form the car storage system according to the preferred embodiment of the present invention. FIG. 10 is a cross-sectional side view showing the mounting of the storage member to the support member in order to form the car storage system according to the preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 3, 4, 5, and 9, the support member of the car storage system of the present invention will be described. Support member 20 comprises sleeves 21A and B pivotally connected at one end. Support member 20 further comprises arms 22A and B slidably mounted within sleeves 21A and B, respectively, wherein arms 22A and B are provided at one end with pivotable flanges 23A and B, respectively, and at their opposite ends with locking mechanisms 24A and B, respectively. The pivotal connection between sleeves 21A and B is created by coupling members 25A and B which are integral to and form part of sleeves 21A and B. Coupling members 25A and 25B extend perpendicularly from one end of sleeves 21A and 21B and terminate in alternately spaced circularly-shaped teeth 26A, 26B, 26C (hereafter 26A-C) and 27A, 27B, 27C (hereafter 27A-C) (See FIG. 5). Each tooth of teeth 26A-C and 27A-C is provided with a hole therethrough such that after teeth 26A-C and 27A-C are fitted together, they form a hinge which has passage 28. Thus, after all the teeth are lined up a pivot pin (not shown) may be fitted through passage 28, thereby, locking teeth 26A-C and 27A-C in place and pivotally connecting sleeves 21A and B together. Furthermore, coupling members 25A and 25B are provided with slots 41 and 42, respectively, which serve as part of the mount for the storage member. The second part of the mount for the storage member is supplied by hooks 40 and 43 of sleeves 21A and 21B, respectively, which are positioned at the ends opposite from coupling members 25A and B. The use of slots 41 and 42 and hooks 40 and 43 to mount the storage member is described herein with reference to FIG. 10. For the purposes of disclosure, only sleeve 21A and arm 22A will be described. However, it is to be understood that sleeve 21B and arm 22B are formed in a similar fashion and operate identically. Sleeve 21A is a rectangularly shaped segment comprised of upper member 29, lower member 30, side members 31 and 32 (see FIG. 9), and end member 47 (see FIGS. 3 and 4) which is integral to coupling member 25A. The inside portions of members 29-32 form opposing slots which serve as rails for arm 22A as it is moved within sleeve 21A. Upper and lower members 29 and 30 are further provided with elongated openings 33 and 34 which allow access to locking mechanism 24A of arm 22A. The end of sleeve 21A opposite to coupling member 25A further has a rectangular opening (not shown) which allows the insertion of arm 22A into the slots of sleeve 21A. Arm 22A is also a rectangularly shaped member which fits through the opening at the unconnected end of sleeve 21A into the two opposing slots formed by the insides of members 29-32. The end of arm 22A held within sleeve 21A has a slight curvature (see FIG. 5) and is connected to locking mechanism 24A. Locking mechanism 24A comprises flexible bar 34, bolt 35, spring 36, and nut 37. To connect locking mechanism 24A to arm 22A, spring 36 is placed between arm 22A and flexible bar 34 with bolt 35 placed through the openings (not shown) in both flexible bar 34 and arm 22A. Nut 37 is then screwed onto bolt 35 to secure flexible bar 34 to arm 22A such that flexible bar 34 bends slightly inward. Although in the preferred embodiment locking mechanism 24A included a nut and bolt to hold the flexible bar in place, one of ordinary skill in the art will readily recognize that a T-shaped molded piece held on arm 22A by a clip could be substituted. Locking mechanism 24A operates by placing tension against side members 31 and 32 of sleeve 21A. The slight inward angle of flexible bar 34 provides a tension which locks arm 22A within sleeve 21A, but still allows arm 22A to be extended outwardly from sleeve 21A. However, the tension against sleeve 21A is sufficient to prevent arm 22A from unintentionally or unexpectedly retracting. To retract arm 22A, flexible bar 34 is pressed inward towards the curvature at the end of arm 22A. That action pulls the ends of flexible bar 34 away from side members 31 and 32, thereby, allowing arm 22 to be manually slid back further into sleeve 21A. The opposite end of arm 22A is provided with pivotable flange 23A which is used in conjunction with pivotable flange 23B to secure support member 20 to the ceiling of an automobile. Arm 22A terminates in alternately spaced teeth 45A-C (see FIG. 4.) while one end of flange 23A is furnished with alternately spaced teeth 46A-C which mesh with teeth 45A-C to form the connection point between arm 22A and flange 23A. Teeth 45A-C and 46A-C are provided with holes therethrough which line up and form a passage (not shown). The passage holds a pivot pin (not shown) which secures teeth 45A-C and teeth 46A-C together, thereby, connecting flange 23A to arm 22A. In the preferred embodiment, flange 23A is not pivotable beyond the completely horizontal position with respect to arm 22A shown in FIG. 3 and may only be pivoted below arm 22A to a point perpendicular to arm 22A. The opposite end of flange 23A is equipped with knife edge 38A which is used to secure flange 23A behind the molding of an automobile ceiling. Once inserted behind the molding, flange 23A is held in place and prevented from pivoting by the tension created against the molding by arm 22A held within sleeve 21A by locking mechanism 24A. Flange 23A is further supplied with lip 39 which, after knife edge 38A is inserted behind the molding, abuts the molding to prevent flange 23A from being over inserted and possibly causing damage to the molding. Referring to FIGS. 6-9, the storage member of the car storage system of the preferred embodiment of the present invention will be described. Storage member 50 comprises storage sections 51 and 52 which in turn are comprised of individual storage compartments 53-68. Storage sections 51 and 52 are connected together in a manner similar to that of sleeves 21A and B of support member 20. That is, one end of each storage section (51 and 52) terminates in circularly-shaped teeth 69 and 70 and circularly-shaped teeth 71 and 72, respectively, which mesh together to form a pivotal connection point. Teeth 69 and 71 are aligned and a pivot pin (not shown) is inserted to connect them together. Similarly, teeth 70 and 72 are aligned and connected together using a second pivot pin (not shown). Unlike sleeve 21A and 21B, however, the connection point between the ends of storage sections 51 and 52 form cavity 73 (see FIG. 9) which is used to connect storage member 52 to support member 20. Positioned within cavity 73 are tabs 74 and 75 which are provided to form the connection point between support member 20 and storage member 50 (discussed herein with reference to FIG. 10). In the preferred embodiment, individual storage compartments 53-68 are formed in a grid-like structure by the wall members which comprise sections 51 and 52 (See FIGS. 8 and 9). In describing the individual storage compartments, only storage section 51 will be referenced, however, it is to be understood that section 52 is constructed similarly and functions identically. Storage section 51 comprises upper member 76, lower member 77, wall members 78-82, center wall member 83, and side wall members 84 and 85. Wall members 78-82 are equally spaced apart in the preferred embodiment and function in conjunction with center wall member 83 to separate upper member 76 from lower member 77 and to partition the space between upper member 76 and lower member 77 into equal compartments. To allow access to the compartments created by members 76-85, upper member 76, lower member 77, and side wall members 84 and 85 are produced with openings (see any of FIGS. 6-9). Although upper member 76 is afforded openings, these openings are covered with flexible covers (see e.g. 86 and 87 as shown in FIG. 8 and FIG. 9) which serve to hold an object placed in one of the compartments pressed firmly against the inside lip created in each of compartments 53-68 by lower member 77 and one of side wall members 84 or 85. Furthermore, upper member 76 extends slightly beyond wall member 82 in order to form tab 88A (described herein with reference to FIG. 10). In the preferred embodiment, the configuration of the storage compartments is best suited to the holding of cassette tapes. However, changes in the configuration of the storage compartments will allow other objects to be firmly secured. Thus, a person skilled in the art will readily recognize that changes in the configuration of the compartments which would allow CD's, mail, facial tissue, loose change, garage openers, maps, gloves, sunglasses, etc. will still fall within the scope of the present invention. Referring to FIGS. 1, 2, and 10, the installation of the present invention along the ceiling of an automobile roof will be described. Support member 20 must first be mounted along the ceiling of the automobile. Arms 22A and 22B are extended until support member 20 is the same width as the automobile ceiling and flanges 23A and 23B will easily reach molding 100 (see FIG. 1). Flanges 23A and 23B are pivoted such that knife edges 38A and 38B may be slid behind molding 100, thereby, securing support member 20 along the car's ceiling. Flanges 23A and 23B are held in place and prevented from pivoting by the tension created against the molding by arms 22A and 22B held within sleeves 21A and 21B by locking mechanisms 24A and 24B. Once support member 20 is in place, storage member 50 must be mounted underneath. Mounting of storage member 50 is accomplished by first folding storage section 51 underneath storage section 52 (see FIG. 10). Storage sections 51 and 52 are pivotal about each other because of their connections along teeth 69 and 71 and teeth 70 and 72 by the two separate pivot pins. Slots 41 and 42, formed within coupling members 25A and B, respectively, provide the support attachments for one end of storage member 50. Tab 75 is slid within slot 42 contained in coupling member 25B (see FIG. 10). After tab 75 is in place, the end opposite from tab 75 is connected to support member 20 by hook 43. Similar to storage section 51, the upper member of storage section 52 extends slightly beyond the last spacer wall to form tab 88B as shown in FIG. 6. Hook 43 is flexible and allows tab 88B to slide past it and into the slot formed between hook 43 and the underside of sleeve 21B (see FIG. 3). Hook 43 then returns to its original position, thus, holding tab 88B and, thereby, storage section 52 in place. Once storage section 52 is in place, storage section 51 is pivoted completely around as shown by the arrow in FIG. 10 until tab 74 resides within slot 41 which is contained within coupling member 25A. Tab 88A of upper member 76 is then inserted as previously described within the slot between hook 40 and lower member 30 to finish the securing of storage member 52 to support member 20. In place, car storage system 10 resides above the heads of the vehicle's occupants and may be placed such that it is easily accessible to a vehicle operator by securing it to the molding in a position directly behind the sun visor as shown in FIG. 2. Once car storage system 10 is affixed, cassette tapes, CD's, maps, gloves, sunglasses, nasal tissue, hand towels, or any other small item carried in an automobile may be secured out of the way, but still in a location which is readily accessible to a vehicle operator. Additionally, after storage member 50 has been removed from support member 20, it functions as a carrying case for the objects stored therein. However, if support member 20 is removed from the automobile with storage member 50 still attached, storage member 50 will still function as a carrying case. From the foregoing description and illustration of this invention, it is apparent that various modifications can be made by reconfigurations or combinations to produce similar results. It is, therefore, the desire of the applicant not to be bound by the description of this invention as contained in this specification, but to be bound only by the claims as appended hereto.

A car storage system is disclosed which mounts to the ceiling of an automobile to provide storage for small items carried by a vehicle operator such as cassette tapes, compact discs, gloves, sunglasses, nasal tissue, and/or maps. The car storage system is adjustably mountable to the ceiling of an automobile such that any of the above items are easily within reach of a vehicle operator. The car storage system comprises a support member which is adjustable to any ceiling width and is mounted using pivotable flanges secured behind the trim molding normally placed about a vehicle's ceiling. A storage member which comprises a plurality of individual storage compartments is removably connected to the support member in order to provide the storage area for any of the above items.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates generally to astragal seals and more particularly to self positioning astragal seals. [0003] 2. Background Art [0004] Double entrance doorways are used in a large variety of residential homes and commercial buildings. Typically, an active door provides for day to day ingress and egress to and from the residential home or building, and an inactive door remains closed, except in instances when a width greater than or equal to the width of the active door and less than or equal to the width of the double entrance doorway is required, such as, for example, for delivery of furniture and/or equipment that cannot fit through the double entrance doorway. If large objects, such as furniture and/or equipment must pass through the double entrance doorway, both the normally inactive door and the active door of the doorway are opened, to create a wide entrance way, through which the furniture and/or equipment may pass. [0005] Mating edges of the inactive door and the active door do not typically contact one another directly, but are separated by an astragal, the astragal being attached to the edge of an inactive leaf, the astragal extending the length of the inactive door, cushioning the closing of the active door and associated inactive leaf of the doorway, and sealing gaps between the inactive door and the active door. [0006] The astragals often have upper and lower bolt-slide assemblies, which lock the astragals and the inactive doors to upper and lower portions of a door frame surrounding the double entrance door way. The upper and lower bolt-slide assemblies have bolts, which slide within upper and lower ends of the astragal, and are pushed outwardly from the inactive door to extend beyond the ends of the astragal, and are received by upper and lower apertures in the upper and lower portions of the door frame, also known as the header and threshold sill, respectively, to lock the inactive door in place. [0007] Stationary seals are typically used at the lower end of the astragals for sealing and preventing drafts from entering the residential homes and/or commercial buildings through the double entrance doorways at the threshold sill. Since many different types, sizes, and shapes of thresholds are used, the drafts remain an unwanted by product of using the stationary sills. In many instances, the fixed size of the seals, and the materials used, for the stationary seals, are either too thick or too thin to fill the gap between the lower end of the astragal and the threshold sill, and, thus, result in not providing an adequate seal, and/or the seal degrading over time. [0008] There is thus a need for a self positioning astragal seal that prevents unwanted drafts, is easy to use and install in a quick, convenient, and efficient manner, is durable and long lasting, maintains its seal against drafts over time, even in situations where repeated opening and closing of the inactive door is necessary, and can be used with a variety of astragals and threshold sills, types, sizes, and shapes of threshold sills, doors, and door frames. [0009] The self positioning astragal seal should be capable of automatically positioning at least one seal at the lower end of the astragal adjacent the threshold sill, and prevent drafts at the vicinity of the lower end of the astragal and the threshold sill, and/or of automatically positioning at least one seal at the upper end of the astragal adjacent the header, and prevent drafts at the vicinity of the header. [0010] The self positioning astragal seal should independently position itself abuttingly adjacent the sill and/or the header when the bolts are extended from a retracted position to an extended position and are received by the upper and/or lower apertures in the upper and/or lower portions of the door frame. [0011] Different astragals have heretofore been known. However, none of the astragals adequately satisfies these aforementioned needs. U.S. Pat. No. 5,857,291 (Headrick) discloses an astragal with integral sealing lock block, for use with a double door installation, which includes an astragal strip secured along a vertical edge of an inactive door. A lock block is slidably disposed in at least one end of the astragal strip, and can be moved between an extended position, for securing the inactive door, and a retracted position for freeing the inactive door. The lock block has a projecting bolt receivable in a receptacle in a door frame, when the lock block is slid to its extended position. A gasket is secured to an end of the lock block, and the bolt passes through an opening in the gasket. The gasket engages and seals against the door frame, when the lock block is in its extended position. Gaskets are also provided on the sides of the lock block, for engaging and sealing against the doors of the double door installation. When the doors are closed and secured in place, the lock block and gasket assembly prevents drafts from flowing under the door installation beneath the astragal thereof. [0012] U.S. Pat. Nos. 5,350,207 and 5,328,217 (Sanders) disclose locking astragals, for attaching to an inactive leaf of a double doorway, and in particular U.S. Pat. No. 5,350,207. Each of the locking astragals has an elongated astragal casing, which has a channel and bolt-slide assemblies mounted slidably within the channel. Each bolt-slide assembly includes a latching member and bolt. By depressing the latching member, the latching member can slide through the channel, to extend and lock the bolts into indentations in upper and lower surfaces of a door frame. The bolts may also be retracted back into the astragal, to open the inactive leaf. Each of the latching members has an integral spring, which simplifies fabrication and assembly. [0013] U.S. Pat. No. 6,491,326 (Massey, et al) discloses a swing adaptable astragal with lockable unitary flush bolt assemblies, for double door entryways, which includes an extruded aluminum frame into which upper and lower flush bolt assemblies are slidably disposed. The flush bolt assemblies include a long metal bolt about which is injection overmolded a series of retainer guides, which ride in the frame. Locking mechanisms are also integrally overmolded onto the bolts. The frame and all components of the astragal assembly are symmetrical and reversible, so that the assembly is non-handed; that is, it can be adapted to both a right hand swing and a left-hand swing inactive door. A strike plate mounting system and bottom-sealing block are provided, and the upper end of the assembly includes means for sealing against a stop of a head jamb. Drafts at upper and lower inside corners of the doors of a double door entryway may be prevented. [0014] U.S. Pat. No. 6,125,584 (Sanders) discloses an automatic door bottom for a hinged door, which is pivotable to be positioned over a sill when closed, the door having a hinge side and a width, the door bottom having an inverted channel having an open bottom, a length corresponding to the door width and a hinge end corresponding to the hinge side of the door; a sealing member having a length corresponding to the length of the channel, the sealing member being housed in the channel and being movable vertically downwardly into a sealing position, in which the sealing member contacts the sill when the door is closed; and a displacement mechanism installed in the channel and coupled to the sealing member, for moving the sealing member vertically into the sealing position in response to closing of the door, wherein the displacement mechanism is coupled to the sealing member at a plurality of points along the length of the sealing member, and is operative to move the end of the sealing member at the hinge side of the channel into the sealing position, prior to the remainder of the sealing member, during closing of the door. [0015] U.S. Pat. No. 6,457,751 (Hartman) discloses a locking assembly for an astragal, which can be attached to an inactive door of a double door unit of a residence or a building. The astragal is attached to an edge of the inactive door in space between the inactive door and active door. A separate locking assembly is attached adjacent a top end of the door and also adjacent a bottom end of the door. A plug having an elongated locking bolt extending therefrom is mounted in a front end of a carriage member. Additional structure is provided for reciprocal travel of the carriage member between a locked position and an unlocked position. [0016] U.S. Pat. No. 5,335,450 (Procton) discloses an astragal, which has an exterior aluminum extrusion and an interior wooden portion. The exterior extrusion includes a pair of rearwardly extending center walls, which form a channel for receiving the wooden interior portion. Attachments and door hardware can be installed in the wooden interior portion, while the extruded exterior acts as cladding. [0017] U.S. Pat. No. 5,590,919 (Germano) discloses a T-astragal and sleeve for door, for use with double swinging doors, such as for french doors. The T-astragal includes a cap portion perpendicular to a base portion, wherein both the cap and base can be formed from wood, such as plywood or plastic. The T-astragal is a molding that extends the full height of the swinging doors. One side of the base portion is fixably coupled to the free end of one of the swinging doors by nails or screws. The free end of the other swinging doors is able to swing up to and against a shoulder portion formed from the cap and base portions. A metal pipe shaped sleeve having an approximate length of one foot is partially positioned along the longitudinal axis of the T-astragal molding. A bolt slides within the sleeve from a rest position to an extended position, where the extended position locks the attached door to a matching slot in the door frame. [0018] U.S. Pat. No. 4,429,493 (St. Aubin) discloses an astragal housing seal and lock, for use in a double door assembly having an active door and a relatively inactive door. The astragal has a vertically extending mullion housing, which is attached to a free edge of the relatively inactive door. A vertically extending slide section is mounted on the mullion housing on a sealing side of the free edge of the inactive door. The slide section extends from the free vertical edge of the inactive door, when the active door is in the closed position. The slide section is vertically movable from an unlocked position to a locked position, wherein the slide section is moved vertically downward, with respect to the mullion housing, to engage the sill/threshold of the door frame, thereby preventing movement of the inactive door. [0019] U.S. Pat. No. 4,058,332 (DiFazio) discloses an astragal and flush bolt assembly to be secured to a relatively stationary member such as a door jamb or to the edge of an inactive door of a pair of double doors or the like. The astragal assembly includes a flat metal body mounted on the edge of the stationary member and a metal stop member secured to the body along one edge thereof. The flat body includes first and second spaced apart legs extending outwardly from the stationary member, with the flat body and legs defining a channel to receive and retain a door latch bolt from the active door. The stop member prevents movement of the door in a first direction, and when the latch bolt is engaged in the channel, the channel and latch bolt prevent the door from moving in the opposite direction. A pair of flush bolts are slidably mounted in the channel, one adjacent each end thereof, so that when the astragal assembly is utilized with double doors, the flush bolts are moved to engage the header and sill, respectively, to hold the inactive door stationary. The astragal body is secured to the stop member by a thermal barrier or thermal break structure, to provide thermal insulation between the inside and the outside of the doors. The stop member also includes a weather strip to form a seal against the active door, and when metal doors or metal covered doors are used, the weather strip may include a magnetic member to form a seal against the active door. [0020] U.S. Pat. No. 6,453,616 (Wright) discloses an astragal for use with exterior double door installations, such as french doors. When attached to the edge of a generally inactive door, the astragal provides a door stop for an active door, a seal to prevent intrusion of water, and a lock for the inactive door. The invention particularly pertains to extruded metal astragals, capable of increasing the resistance of the double door system to high wind conditions. The astragal comprises a longitudinally extending base member that has at least one longitudinally extending channel and a pair of spaced apart outwardly extending legs. At least one bolt is slidably inserted in the channel adjacent to one of the first and second ends of the channel. The astragal is attached to the door, by at least one cleat whose spaced apart arms engage the legs of the base member, providing resistance to the astragal rocking in relation to the door edge, when the doors are subject to wind forces. [0021] U.S. Pat. No. D293,719 discloses a combined astragal extrusion and seal. For the foregoing reasons, there is a need for a self positioning astragal seal that prevents unwanted drafts, is easy to use and install in a quick, convenient, and efficient manner, is durable and long lasting, maintains its seal against drafts over time, even in situations where repeated opening and closing of the inactive door is necessary, and can be used with a variety of astragals and threshold sills, types, sizes, and shapes of threshold sills, doors, and door frames. The self positioning astragal seal should be capable of automatically positioning at least one seal at the lower end of the astragal adjacent the threshold sill, and prevent drafts at the vicinity of the lower end of the astragal and the threshold sill, and/or of automatically positioning at least one seal at the upper end of the astragal adjacent the header, and prevent drafts at the vicinity of the header. The self positioning astragal seal should independently position itself abuttingly adjacent the sill and/or the header when the bolts are extended from a retracted position to an extended position and are received by the upper and/or lower apertures in the upper and/or lower portions of the door frame. SUMMARY [0022] The present invention is directed to a self positioning astragal seal that automatically positions at least one seal at the lower end of an astragal adjacent the threshold sill of a door frame, and prevent drafts at the vicinity of the lower end of the astragal and the threshold sill, and/or of automatically positions at least one seal at the upper end of the astragal adjacent the header of the door frame, and prevent drafts at the vicinity of the header. The self positioning astragal seal independently positions itself abuttingly adjacent the sill and/or the header when the astragal's bolts are extended from a retracted position to an extended position and are received by the upper and/or lower apertures in the upper and/or lower portions of the door frame. The self positioning astragal seal prevents unwanted drafts, is easy to use and install in a quick, convenient, and efficient manner, is durable and long lasting, maintains its seal against drafts over time, even in situations where repeated opening and closing of the inactive door is necessary, and can be used with a variety of astragals and threshold sills, types, sizes, and shapes of threshold sills, doors, and door frames. [0023] A self positioning astragal seal, for use with an astragal having a bolt having a bolt retracted position and a bolt extended position, having features of the present invention comprises: a seal block having a catch and a hole, the bolt slidably disposed through the hole, the catch catching a portion of the bolt and holding the seal block in a seal block retracted position when the bolt is in the bolt retracted position and releasing the seal block when the bolt is in the bolt extended position; spring means forcing the seal block into a seal block extended position when the seal block is released. [0024] An astragal having a self positioning astragal seal having features of the present invention comprises: an astragal body; a bolt having a bolt retracted position and a bolt extended position; a seal block having a catch and a hole, the bolt slidably disposed through the hole, the catch catching a portion of the bolt and holding the seal block in a seal block retracted position when the bolt is in the bolt retracted position and releasing the seal block when the bolt is in the bolt extended position; spring means forcing the seal block into a seal block extended position when the seal block is released. DRAWINGS [0025] 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: [0026] FIG. 1 is a perspective view of a self positioning astragal seal, constructed in accordance with the present invention, shown extended; [0027] FIG. 2 is a perspective view of the self positioning astragal seal, shown retracted; [0028] FIG. 3 is an exploded view of the self positioning astragal seal and a latching mechanism; [0029] FIG. 4 is an exploded view of selected components of the self positioning astragal seal and a portion of the latching mechanism of FIG. 3 ; [0030] FIG. 5 is an exploded view of the latching mechanism of FIG. 3 ; [0031] FIG. 6 is a perspective view of entrance doors, comprising an inactive door, shown in a closed position, and an active door; [0032] FIG. 7 is a perspective view of the inactive door, showing the self positioning astragal seal and an astragal installed thereon the inactive door, with the self positioning astragal seal extended; [0033] FIG. 8 is a section view of the self positioning astragal seal, shown extended; [0034] FIG. 9 is another section view of the self positioning astragal seal, shown extended; [0035] FIG. 10 is another section view of the self positioning astragal seal, with the self positioning astragal seal extended; [0036] FIG. 11 is another section view of the self positioning astragal seal, with the self positioning astragal seal extended; [0037] FIG. 12 is another section view of the self positioning astragal seal, with the self positioning astragal seal extended; [0038] FIG. 13 is another section view of the self positioning astragal seal, with the self positioning astragal seal extended; [0039] FIG. 14 is another section view of the self positioning astragal seal, with the self positioning astragal seal extended; [0040] FIG. 15 is a section view of the latching mechanism of FIG. 3 , along a portion of line 8 - 8 of FIG. 7 , with the self positioning astragal seal extended; [0041] FIG. 16 is a section view of the self positioning astragal seal, along a portion of line 8 - 8 of FIG. 7 , with the self positioning astragal seal extended; [0042] FIG. 17 is a section view of the self positioning astragal seal, shown retracted; [0043] FIG. 18 is another section view of the self positioning astragal seal, shown retracted; [0044] FIG. 19 is an exploded view of an upper bolt and latching mechanism of the astragal of FIG. 7 . [0045] FIG. 20 is a section view of the self positioning astragal seal shown with an alternate embodiment of an astragal installed thereon the inactive door; [0046] FIG. 21 is a section view of the self positioning astragal seal shown with an alternate embodiment of an astragal installed thereon the inactive door; [0047] FIG. 22 is a section view of the self positioning astragal seal shown with an alternate embodiment of an astragal installed thereon the inactive door, and also showing the active door; [0048] FIG. 23 is a section view of the self positioning astragal seal shown with an alternate embodiment of an astragal installed thereon the inactive door, and also showing the active door; [0049] FIG. 24 is a section view of the self positioning astragal seal shown with an alternate embodiment of an astragal installed thereon the inactive door, and also showing the active door; and [0050] FIG. 25 is a section view of the self positioning astragal seal shown with an alternate embodiment of an astragal installed thereon the inactive door, and also showing the active door. REFERENCE NUMERALS [0051] These and other features, aspects, and advantages of the present invention will become better understood with regard to the references and associated reference numerals of the following description and accompanying drawings where: 10 self positioning astragal seal 12 seal block 14 seal block hole 16 shoulder 18 compression spring 20 end seal 30 astragal 42 inactive door edge 44 inactive door 46 sill 48 door frame 52 elongated guide 54 elongated guide channel 56 lower bolt 58 shoulder 60 astragal bottom 74 seal block bottom 78 seal block base 80 face plate 82 guide block 84 “T” shaped member 86 compression spring guide holder 88 compression spring bottom end 90 base top 92 barrel 94 barrel extension 96 barrel extension arcuate interior 98 extension 100 extension arcuate interior 102 T top portion 104 arcuate interior 105 angled edges 106 shoulder 108 face plate reinforcement 110 face plate stop 112 guide block edge stop 114 guide block reinforcement 116 guide block stop 130 astragal recess 132 astragal extension stop 134 astragal retraction stop 136 astragal opposing side 138 astragal side portion 140 astragal side 142 side channel 144 threaded hole 146 threaded hole 148 set screw 150 angled longitudinal channel edge 152 compression spring top end 154 seal hole 156 face seal 158 face plate exterior side 160 active door edge 162 active door 164 header 166 seal peel off adhesive strip 168 face seal peel off adhesive strip 180 astragal housing 182 longitudinal channel 184 longitudinal retention guide 185 channel base 186 lockset strike 188 deadbolt strike 190 upper bolt 191 upper bolt assembly 192 lockset 194 deadbolt 196 lockset cover plate 198 deadbolt cover plate 199 screws 200 latching member 202 pull block 204 elongated connector 206 compression spring 208 slide plate 210 bolt lower portion 212 bolt mid portion 214 bolt upper portion 216 bolt slot 218 bolt hole 220 end pin 222 elongated connector hole 224 pin 226 pin 228 pull block track 230 pull block retention track 232 pull block retention track 234 pull block channel 236 pull block channel 238 pull block notch 240 pull block base 242 pull block notch 244 pull block bearing notch 246 pull block notch side 248 lever arm receiving hole 250 lever arm 252 trunnion 254 spring tail 256 latching dog 260 slide plate retraction hole 262 slide plate extension hole 264 slide plate notch 266 slide plate end tab 268 slide plate projecting tab 270 slide plate projecting notch 280 elongated guide notched recess 282 elongated guide end 284 pull block arrow marking 286 arcuate side 288 arcuate base 300 alternate astragal housing 302 saw tooth recess 304 finned tail 306 foam weather strip 308 cavity 310 alternate astragal housing 312 thermal break 314 slot 320 alternate astragal 322 alternate astragal housing 324 cover 326 outer seal 328 inner seal 330 alternate astragal 332 thermal break 340 alternate astragal 342 cover element 344 saw tooth recess 346 finned tail 348 weather strip seal 349 inner seal 350 alternate astragal 352 thermal break DESCRIPTION [0186] The preferred embodiments of the present invention will be described with reference to FIGS. 1-25 of the drawings. Identical elements in the various figures are identified with the same reference numbers. [0187] FIGS. 1-19 show an embodiment of the present invention, a self positioning astragal seal 10 , which comprises a seal block 12 having a substantially centrally disposed hole 14 therethrough, a shoulder 16 , compression springs 18 , and end seal 20 , for use with an astragal 30 . [0188] The astragal 30 is mounted to edge 42 of inactive door 44 , and the self positioning astragal seal 10 is mounted to the astragal 30 adjacent sill 46 of door frame 48 , as shown in FIGS. 6 and 7 . The astragal 30 has an elongated guide 52 having a substantially centrally disposed longitudinal channel 54 and a bolt 56 having a shoulder 58 , the bolt 56 slidably mounted therein the substantially centrally disposed longitudinal channel 54 . [0189] The astragal seal shoulder 16 catches the bolt shoulder 58 when the bolt 56 is retracted to a retracted position, as shown in FIGS. 2, 17 , and 18 , and is released from the bolt shoulder 58 when the bolt 56 is extended to an extended position, as shown in FIGS. 1 and 7 - 16 , the compression springs 18 forcing the seal block 12 into an extended position, when the bolt 56 is in the bolt extended position. The seal block 12 is, thus, retracted to a retracted position, the astragal seal shoulder 16 catching and abutting the bolt shoulder 58 , and holding the seal block 12 in a seal block retracted position when the bolt 56 is in the bolt retracted position. The seal block 12 is extended to the seal block extended position, when the astragal seal shoulder 16 is released from the bolt shoulder 58 , the compression springs 18 forcing the seal block 12 into the seal block extended position, when the bolt 56 is in the bolt extended position. The astragal seal shoulder 16 , thus, acts as a catch, which catches the bolt shoulder 58 when the bolt 56 is retracted to the bolt retracted position, and is released from the bolt shoulder 58 when the bolt 56 is extended to the bolt extended position. [0190] The self positioning astragal seal 10 automatically and independently adjusts itself to fit snugly and fill any gaps between bottom 60 of the astragal 30 and the sill 46 of the door frame 48 , when the bolt 56 is in the bolt extended position, thus, preventing unwanted drafts between bottom 74 of the seal block 12 and the sill 46 of the door frame 48 , the compression springs 18 forcing the seal block 12 opposingly away from the bottom 60 of the astragal 30 and forcing the end seal 20 , which is affixed to the bottom 74 of the seal block 12 , to abut the sill 46 of the door frame 48 . [0191] The seal block 12 has base 78 , face plate 80 , and guide block 82 , which is adjacent the inactive door edge 42 , when the self positioning astragal seal 10 and the astragal are installed on the inactive door 44 and the seal block 12 is in the retracted position, the face plate 80 and the guide block 82 being substantially perpendicular to the base 78 , and substantially parallel one to the other. [0192] The seal block 12 has substantially “T” shaped member 84 integral with the guide block 82 and compression spring guide holders 86 , which hold the compression springs 18 in place, the compression springs 18 being mounted about the compression spring holders 86 , with bottom ends 88 of the compression springs 18 abutting top 90 of the base 78 . The seal block 12 has barrel 92 integral with the guide block 82 , the barrel 92 having the substantially centrally disposed hole 14 therethrough to the bottom 74 of the seal block 12 , the bolt 56 slidable therethrough the substantially centrally disposed hole 14 , and the seal block 12 slidable about the bolt 56 . The barrel 92 has extension 94 , which is integral with the barrel 92 , having arcuate interior 96 , which is substantially collinear with the interior of the barrel 92 , and extension 98 having the shoulder 16 and arcuate interior 100 . The substantially “T” shaped member 84 has T top portion 102 , which has arcuate interior 104 , angled edges 105 , and shoulder 106 . The face plate 80 has reinforcements 108 having stops 110 . The guide block 82 has edge stops 112 and reinforcements 114 having stops 116 . The compression spring holders 86 have splines for reinforcement. [0193] The elongated guide 52 of the astragal 30 has recesses 130 , which have extension stops 132 and retraction stops 134 at opposing ends thereof, and substantially planar opposing side 136 . The elongated guide 52 of the astragal 30 has substantially planar side portions 138 adjacent the recesses 130 , which oppose the substantially planar opposing side 136 , and sides 140 , which are substantially perpendicular to the substantially planar side portions 138 , the recesses 130 , and the substantially planar opposing side 136 . The elongated guide 52 also has opposing longitudinally disposed side channels 142 . The substantially planar side portions 138 and the substantially planar opposing side 136 have threaded holes 144 and 146 , respectively, therethrough, opposing one another, having set screws 148 therein, the set screws 148 extending across the longitudinally disposed side channels 142 . The elongated guide 52 also has angled longitudinal edges 150 atop the substantially centrally disposed longitudinal channel 54 adjacent the recesses 130 and the substantially planar side portions 138 . [0194] The substantially “T” shaped member 84 and the face plate 80 of the seal block 12 matingly sandwich the recesses 130 and the substantially planar opposing side 136 of the astragal 30 , respectively, therebetween, and retain the seal block 12 slidably mating about the elongated guide 52 between the seal block retracted position and the seal block extended position, and vice versa. [0195] The compression springs 18 are mounted about the compression spring holders 86 , with the bottom ends 88 of the compression springs 18 abutting the top 90 of the base 78 of the seal block 12 and top 152 of the compression springs 18 abutting the set screws 148 in the longitudinally disposed side channels 142 of the astragal 30 . The compression springs 18 are held in the longitudinally disposed side channels 142 of the astragal 30 under compression, the extension stops 132 of the astragal 30 preventing the compression springs 18 from forcing the substantially “T” shaped member 84 out of the recesses 130 . [0196] The barrel 92 of the seal block 12 is matingly slidable about the bolt 56 of the astragal 30 , and the bolt 56 is matingly slidable therethrough the substantially centrally disposed hole 14 of the barrel 92 of the seal block 12 . The angled edges 105 of the substantially “T” shaped member 84 matingly abut the angled longitudinal edges 150 of the astragal 30 . The angled edges 105 of the substantially “T” shaped member 84 and the barrel 92 of the guide block 82 guide the seal block 12 collinearly with the angled longitudinal edges 150 of the astragal 30 and the substantially centrally disposed longitudinal channel 54 , the bolt 56 being substantially aligned with the substantially centrally disposed longitudinal channel 54 . [0197] The extension stops 132 and the retraction stops 134 limit the extent of travel of the substantially “T” shaped member 84 , and, thus, limit the extent of travel of the seal block 12 and the end seal 20 from the seal block extended position to the seal block retracted position, respectively, the compression springs 18 forcing the seal block 12 into the extended position, other than when the seal block 12 is retracted. The seal block 12 is retracted to the retracted position, the astragal seal shoulder 16 catching and abutting the bolt shoulder 58 , and holding the seal block 12 in the seal block retracted position, when the bolt 56 is in the bolt retracted position. The seal block 12 is extended to the seal block extended position, when the astragal seal shoulder 16 is released from the bolt shoulder 58 , the compression springs 18 forcing the seal block 12 into the seal block extended position, when the bolt 56 is in the bolt extended position. The end seal 20 has substantially centrally disposed hole 154 therethrough, which is substantially aligned collinearly with the substantially centrally disposed hole 14 of the seal block 12 , which allows the end seal 20 to slide about the bolt 56 , and vice versa. The self positioning astragal seal 10 has face seal 156 , which is affixed to exterior side 158 of the face plate 78 of the seal block 20 and abuts edge 160 of active door 162 , when the active door 162 is closed abuttingly against the inactive door 44 , thus, preventing unwanted drafts between the self positioning astragal seal 10 and the edge 160 of the active door 162 . The astragal 30 also has edge seal 163 . [0198] The self positioning astragal seal 10 may be used with the astragal 30 adjacent the sill 46 and/or header 164 of the door frame 48 , and may be used with the inactive door 44 and/or the active door 162 . Typical installations, however, have the astragal 30 mounted to the edge 42 of the inactive door 44 , and the self positioning position astragal end seal 20 mounted to the astragal 30 adjacent the sill 46 . [0199] The self positioning astragal seal 10 may be used with a variety of astragals but is preferably used with the astragal 30 shown in the accompanying figures. Other astragals may be modified to suit the needs of particular applications. [0200] The end seal 20 and the face seal 156 may have adhesives covered by peel off adhesive strips 166 and 168 , respectively, the end seal 20 and the face seal 156 being fastened to the seal block 12 with the adhesives, upon removal of the adhesive strips 166 and 168 , respectively. [0201] The astragal 30 has astragal housing 180 having longitudinal channel 182 , which has longitudinal retention guides 184 , the elongated guide 52 inserted into the longitudinal channel 182 and held in the longitudinal channel 182 by the retention guides 184 and the set screws 148 , and channel base 185 , the set screws 148 locking the elongated guide 52 into the astragal housing 180 . The astragal 30 also has lockset strike 186 , deadbolt strike 188 , and upper bolt 190 mounted to the longitudinal channel 182 of the astragal housing 180 , the bolt 56 and the upper bolt 190 being used to lock the astragal 30 , and, thus, the inactive door 44 , which the astragal 30 is affixed to, to the sill 46 and the header 164 , respectively, of the door frame 48 . The upper bolt 190 may be used with the self positioning astragal seal 10 and/or alternatively the upper bolt 190 may use an alternative sealing means. Upper bolt assembly 191 having the upper bolt 190 is installed into the longitudinal channel 182 in substantially the same manner as the elongated guide 52 . The active door 162 has lockset 192 and deadbolt 194 , which are received by lockset strike 186 , deadbolt strike 188 , respectively, on the inactive door 44 , for securing the active door 162 to the inactive door 134 when the active door 162 is closed abuttingly adjacent the inactive door 44 . The astragal housing 180 has lockset cover plate 196 and deadbolt cover plate 198 , which are mounted to the astragal housing 180 , the lockset strike 186 and the deadbolt strike 188 being fastened to the lockset cover plate 196 and the deadbolt cover plate 198 with screws 199 . [0202] The astragal 30 has latching member 200 , pull block 202 , elongated connector 204 , compression spring 206 about the elongated connector 204 , and slide plate 208 . The bolt 56 has lower portion 210 , mid portion 212 adjacent the shoulder 58 , the mid portion 212 having a smaller diameter than the diameter of the lower portion 210 , and upper portion 214 , the upper portion 214 of the bolt 56 having substantially the same diameter as the lower portion 210 , and having a slot 216 therethrough and a hole 218 therethrough, the slot 216 and the hole 218 substantially perpendicular one to the other. [0203] The elongated connector 204 has end pin 220 , opposing hole 222 , and pin 224 therebetween, the end pin 220 and the pin 224 substantially perpendicular to the plane of the elongated connector 204 . The elongated connector 204 is sandwiched in the slot 216 of the upper portion 214 of the bolt 56 , the hole 218 and the hole 222 aligned one with the other, the bolt 56 and the elongated connector 204 pinned one to the other with pin 226 , the pin 226 therethrough the holes 222 and 218 . [0204] The pull block 202 has longitudinal tracks 228 , retention tracks 230 and 232 , and channels 234 and 236 , the channels 234 between the longitudinal tracks 228 and the retention tracks 230 , and the channels 236 between the longitudinal tracks 230 and the retention tracks 232 . The pull block 202 is inserted into the longitudinal channel 182 of the astragal housing 180 , the channels 234 and 236 being adjacent to the retention guides 184 of the astragal housing 180 , the retention guides 184 slidably retaining the pull block 204 in the astragal housing 180 . The pull block 202 has substantially centrally disposed notch 238 at base 240 of the pull block 202 , notch 242 adjacent and substantially perpendicular to the substantially centrally disposed notch 238 , and bearing notches 244 . The substantially centrally disposed notch 238 is adjacent to and surrounds the elongated connector 204 adjacent the end pin 220 of the elongated connector 204 ; and sides 246 of the notch 242 surround and abut the end pin 220 , thus, pinning the elongated connector 204 to the pull block 202 one to the other. The pull block 202 also has lever arm receiving hole 248 . [0205] The latching member 200 has lever arm 250 , which has trunnions 252 protruding therefrom, spring tail 254 , and latching dog 256 . [0206] The slide plate 208 has retraction hole 260 , extension hole 262 , notches 264 , which form end tabs 266 , and projecting tabs 268 , which form projecting notch 270 therebetween, the projecting notch 270 for matingly slidably receiving the elongated connector 204 therebetween. [0207] The elongated guide 52 is locked into the astragal housing 180 with the set screws 148 . The elongated guide 52 has notched recesses 280 opposing the recesses 130 , the notched recesses 280 matingly receiving the end tabs 266 of the slide plate 208 therein, and adjacent ends 282 , the notches 264 of the slide plate 208 matingly receiving the ends 282 of the elongated guide 52 therein, the slide plate 208 being sandwiched and locked between the elongated guide 52 and the channel base 185 of the astragal housing 180 . The projecting notch 270 of the slide plate 208 slidably guides the elongated connector 204 , which is located in the projecting notch 270 , substantially collinear with the center line of the elongated guide 52 . The latching member 200 is sandwiched between the pull block 202 and the slide plate 208 , with the trunnions 252 in the bearing notches 244 of the pull block 202 and the lever arm 250 extending through the lever arm receiving hole 248 of the pull block 202 , thus facilitating operator control. [0208] The retraction hole 260 and the extension hole 262 of the latching member 200 matingly receive the latching dog 256 of the latching member 200 therein. [0209] The latching member 200 may be retracted to a latching member retracted position, when the lever arm 250 of the pull block 202 is depressed and pushed in the direction of pull block arrow marking 284 , which pulls the elongated connector 204 in the direction of the pull block arrow marking 284 , pulls the bolt 56 into the bolt retracted position, pulls the seal block 12 into the seal block retracted position, compresses the compression springs 18 , and compresses the compression spring 206 between the pin 224 of the elongated connector 204 and the projecting tabs 268 of the slide plate 208 . When the latching member 200 is retracted to the latching member retracted position, the spring tail 254 of the latching member 200 forces the latching dog 256 into the retraction hole 260 of the slide plate 208 , thus, locking the bolt 56 into the bolt retracted position and locking the seal block 12 into the seal block retracted position. [0210] The latching member 200 may be released into a latching member extended position from the latching member retracted position, when the lever arm 250 of the pull block 202 is depressed and released, releasing compression from the compression spring 206 between the pin 224 of the elongated connector 204 and the projecting tabs 268 of the slide plate 208 , forcing the elongated connector 204 in the direction opposing the pull block arrow marking 284 , forcing the bolt 56 into the bolt extended position, releasing compression on the compression springs 18 , which forces the seal block 12 into the seal block extended position. When the latching member 200 is released, the latching member 200 snaps into latching member extended position, the latching dog 256 snaps into the extension hole 262 of the slide plate 208 , the spring tail 254 of the latching member 200 forcing the latching dog 256 into the extension hole 262 , thus, locking the bolt 56 into the bolt extended position with the seal block 12 in the seal block extended position, the seal block 12 automatically and independently self positioned with the end seal 20 abutting the sill 46 of the door frame 48 . The latching member 200 may alternatively be pushed into the latch member extended position. [0211] The substantially centrally disposed longitudinal channel 54 of the elongated guide 52 has arcuate sides 286 and arcuate base 288 to slidably and matingly accommodate the bolt 56 , the lower portion 210 and the mid portion 212 of which are substantially cylindrical and have substantially the same diameter. The mid portion 212 of the bolt 56 is also substantially cylindrical, but has a smaller diameter than the diameter than that of the lower portion 210 and the upper portion 214 . [0212] The astragal housing 180 and the elongated guide 52 are preferably of metal, such as aluminum or steel, thermoplastics, thermosetting polymers, rubber, or other suitable material or combination thereof. [0213] The seal block 12 and the latching member 200 are preferably injection molded from an engineered plastic resin that has properties to provide flexural strength, such as an acetal, although other suitable materials may be used. The end seal 20 and the face seal 156 are preferably of cellular material, such as closed cell neoprene sponge, although other suitable materials may be used. [0214] FIG. 15 shows the latching member 200 with the lever arm 250 depressed and the latching dog 256 ready to be moved to the retraction hole 260 of the slide plate 208 , which is shown after being moved in FIGS. 17 and 18 . The seal block 12 is also retracted along with the bolt 56 , when the latching dog 256 is moved into the retraction hole 260 , as shown in FIGS. 17 and 18 . [0215] The active door 162 and the inactive door 44 are “handed” as either right hand, in which the hinges of the active door 162 are on the right side of the active door 162 as viewed from the outside of the door frame 48 and left hand if the hinges of the active door 162 are on the left side of the door frame 48 as viewed from the outside of the door frame 48 . The elongated guide 52 and the self positioning astragal seal 10 may easily be reversed from left hand to right hand, and vice versa, by merely loosening the set screws 148 , removing the elongated guide 52 with the self positioning astragal seal 10 from the longitudinal channel 182 of the astragal housing 180 , and installing the elongated guide 52 with the self positioning astragal seal 10 on the end of the astragal housing 180 opposing that from which it was removed, thus, converting the astragal 30 from one hand to the other. [0216] FIGS. 20-25 show alternate embodiments of astragals having astragal housings that the self positioning astragal 10 may be used with, although other suitable astragals having other suitable astragal housings may be used. [0217] FIG. 20 shows an alternate embodiment of an astragal housing 300 , which has a saw-tooth recess 302 to retain finned tail 304 of a typical wrapped foam type weather strip 306 for sealing. The astragal housing 300 also has cavity 308 . [0218] FIG. 21 shows an alternate embodiment of an astragal housing 310 , which is substantially the same as the astragal housing 300 , except that the astragal housing 310 has thermal break 312 , for installations in climates that experience extremely cold weather, in which the astragal housing 310 is fabricated from an aluminum extrusion, or other suitable material having substantially the same properties, which would otherwise readily lose heat to the outside and result in condensation, and in some cases even the formation of ice. The thermal break 312 is created by filling cavity 308 of the astragal housing 300 with a polyurethane thermal break compound, after which it is de-bridged by milling slot 314 , thus, separating outer and inner portions of the astragal housing 310 and preventing infiltration of the cold. [0219] FIG. 22 shows an alternate embodiment of an astragal 320 , which may be used for installation on a pair of outwsinging rather than inswinging doors, which has astragal housing 322 , cover 324 that provides overlap, and outer seal 326 , and is used on the active leaf of the pair of out swinging doors. Inner seal 328 is of greater reach as the beveled edge of the active door is reversed, creating a greater gap at its inner edge. [0220] FIGS. 23 shows an alternate embodiment of an astragal 330 , which may be used for installation on a pair of outwsinging rather than inswinging doors, which is substantially the same as the astragal housing 320 , except that the astragal 330 has thermal break 332 . [0221] FIG. 24 shows an alternate embodiment of an astragal 340 , which may be used for installation on a pair of outwsinging rather than inswinging doors, in which cover element 342 has saw-tooth recess 344 to accommodate finned tail 346 of a wrapped foam weather strip seal 348 . Inner seal 349 is of greater reach as the beveled edge of the active door is reversed, creating a greater gap at the inner edge. [0222] FIGS. 25 shows an alternate embodiment of an astragal 350 , which may be used for installation on a pair of outwsinging rather than inswinging doors, which is substantially the same as the astragal housing 340 , except that the astragal 350 has thermal break 352 . [0223] 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 description of the preferred versions contained herein.

A self positioning astragal seal that automatically positions at least one seal at the lower end of an astragal adjacent the threshold sill of a door frame, and prevents drafts at the vicinity of the lower end of the astragal and the threshold sill, and/or of automatically positions at least one seal at the upper end of the astragal adjacent the header of the door frame, and prevent drafts at the vicinity of the header. The self positioning astragal seal independently positions itself abuttingly adjacent the sill and/or the header when the astragal's bolts are extended from a retracted position to an extended position and are received by the upper and/or lower apertures in the upper and/or lower portions of the door frame, is easy to use, install, and can be used with a variety of astragals and threshold sills, types, sizes, and shapes of threshold sills, doors, and door frames.

BACKGROUND OF THE INVENTION [0001] The present invention relates to a telecommunication architecture and associated method of extending quality of service (QOS) control beyond the network edge, and, more specifically, to an auto adaptive full duplex QOS mechanism for customer premises equipment (CPE), such as a residential/enterprise gateway. [0002] The “background” description provided herein is for the purpose of generally presenting the context of the invention. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention. [0003] Currently, QOS is primarily controlled internal to the network edge (i.e., network core or “backbone”) via a multitude of routing and resource allocation mechanisms. In a typical Wide Area Network (WAN) environment, the Internet for example, link-state routing protocols, MPLS, and/or MPLS related traffic engineering protocols, Diffserv, etc are leveraged to ensure a guaranteed level of bandwidth for meeting application and/or customer delivery requirements. Theses mechanisms may interface with carrier and edge policies to further improve communication latencies, and, to adjust traffic shaping metrics. While these techniques are highly effective, customer premises equipment, which by its nature is external to the network edge, cannot benefit from such network management schemes and QOS technologies. [0004] Virtual Private Lan Services (VPLS) provides one solution to extending network management technologies and QOS control beyond the network edge. This mechanism is currently being pursued by the Internet Engineering Task Force (IETF) to provide metro Ethernet integration. However, competing protocols and methodology are complicating the adoption of this technology. Further, the adoption of such an increasingly complex layering of control and routing protocols is not a cost effective solution for residential and/or most smaller to medium sized enterprise customers. [0005] In today's residential and/or home network envrionment, residential CPE equipment such as a gateway, cable modem, etc is provided to deliver basic connectivity to an external network. This basic interface provided by the service provider does not provide any QOS funtionality, nor can it shape traffic exchanged therethrough in an upstream or downstream direction. The extension of connectivity from an external network edge to CPE equipment is referred to as “the last mile.” As most of the traffic shaping is done at the edge of the network by the service provider, there exists a deficiency in QOS control in the last mile. Consequently, many residential customers, get very bad quality of service due to bandwidth limitations in the last mile. [0006] For example, current residential services, whether offered over DSL, cable modem ,or by Wireless Service Provider (WISP), do not guarantee QoS to the customer. Such services include real time A/V streaming, Voice Over IP applications such as emergency 911 calling, on-line gaming and virtual reality environments, and so called “triple play” (IPTV) delivery etc. Likewise, there is no way by which a priority can be assigned to data streams in the last mile such that one data stream, or “active session,” can be given priority with respect to available last mile resources. [0007] Accordingly, there is a need for an adaptive architecture which provides quality of service beyond the network edge to manage, at the session level, both upstream and downstream traffic for the last mile. SUMMARY OF THE INVENTION [0008] The present invention provides a customer premises device or “gateway” to monitor and manage quality of service (QOS) levels for traffic between a network edge and a customer. The gateway includes a memory which stores at least one user profile, and, information regarding active sessions of traffic flow through the gateway. A hardware and/or software/firmware based controller monitors traffic flow between the customer and the network edge, and, manages requests for new active sessions. The controller initiates access to the at least one user profile stored in memory to identify a policy hierarchy with respect to active sessions of traffic flow upon receipt of a request to establish a new active session. The controller selects an active session to be terminated based upon the policy hierarchy and terminates the selected session in accordance with information stored in memory regarding the selected session. In this manner, the controller enforces quality of service, for both upstream and downstream sessions, based upon the policy hierarchy defined by the user profile. [0009] In a further aspect of the invention, a method of policing quality of service (QOS) for active sessions of a customer premises device positioned between a network edge and a customer is provided. The method includes storing at least one user defined policy hierarchy, and, information regarding active sessions of traffic flow through the customer premises device. Active sessions between the customer and the network edge are monitored. Upon reception of a request for establishing a new active session, the memory is accessed for retrieving the at least one user profile. A policy hierarchy with respect to active sessions of traffic flow is identified from the at least one user profile, and, an active session is selected to be terminated in accordance with the at least one user defined policy hierarchy. The selected active session is discontinued in accordance with the information of the memory and the newly requested new active session is established. In this way, the quality of service policies are enforced for both upstream and downstream sessions, based upon the user defined policy hierarchy. [0010] In still a further aspect of the invention, a method of policing quality of service (QOS) for active sessions of a customer premises device positioned between a network edge and a customer is provided. The method includes storing at least one user defined policy, and, information regarding active sessions of traffic flow through the customer premises device. Active sessions between the customer and the network edge are monitored, and, the memory is accessed for retrieving the at least one user profile. Groups of traffic metrics with respect to active sessions of traffic flow are identified from the at least one user profile, and, an active session is selected to be terminated upon violation of a metric defined in the user profile. The selected active session is discontinued in accordance with the information of the memory. In this way, the quality of service policies are enforced for both upstream and downstream sessions, based upon the user defined policy. [0011] It is to be understood that both the foregoing general description of the invention and the following detailed description are exemplary, but are not restrictive, of the invention. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0012] A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: [0013] FIG. 1 is a network diagram including the architecture of the present invention; [0014] FIG. 2 is a block diagram of a gateway device in accordance with an exemplary architecture of the invention; [0015] FIG. 3 is a high level block diagram of a guardian control module of the gateway device of FIG. 2 ; [0016] FIG. 4 is a flowchart describing an exemplary traffic shaping operation of the control and management module of FIG. 3 ; and [0017] FIG. 5 is a flowchart describing a further exemplary traffic shaping operation of the control and management module of FIG. 3 . DETAILED DESCRIPTION OF THE INVENTION [0018] Certain terminology used in the following description is for convenience only and is not limiting. The term “gateway” as used herein refers to hardware and/or software functioning to interface between a customer/enterprise and a provider edge. No functionality is either implied or inferred from the use of the term “gateway” aside from that described herein. Likewise, “customer premises” is not limited with respect to physical location, but, instead, merely denotes functionality with respect to the exchange of traffic with a customer. As such, the customer premises device (CPE) may be physically located at any distance from home network or enterprise network point of presence. The ability to pass communications therebetween being a function of the transmission range, power and wireless/hardwire application protocol of the respective devices. In the drawings, the same reference numerals are used for designating the same elements throughout the several figures. [0019] The present invention is directed to a device for managing traffic flow between a customer and a network provider access point (AP). The AP or “customer premises device” in accordance with the present invention provides intelligent control of full duplex data streams to shape the upstream or downstream traffic from within the home network to address the “last mile problem.” The device admits, controls, and shapes both upstream and downstream traffic (inbound and outbound streams). Intelligence embedded in the customer premises device as described herein provides an architecture which polices quality of service and bandwidth management for every session in accordance with user defined priorities. The user defined priorities may dictate the management of additional active session requests to maintain minimum levels of performance, and/or dictate the termination of active sessions upon exceeding of such minimum levels by presently established active sessions. [0020] In monitoring active sessions, the device in accordance with the present invention relates each active session of traffic to a priority level of a policy hierarchy provided in a user profile. Each session is associated with a profile that specifies in addition to other parameters, a session's priority level and a session's QoS parameters, such as maximum tolerable delay, minimum throughput, maximum variance of the delay (jitter), etc. In this way, a determination is made whether a session's policy has exceeded or fallen below a user defined requirement, or, can be supported by the network: (a) by either the network providing sufficient capacity or resources to support the QoS, or (b) by dropping some lower priority session to accommodate the QoS requirements of the higher priority session. [0021] The present invention may be embodied to provide functions which are part of existing CPE equipment, such as residential gateways, to strictly monitor each session maintained by the gateway, to retrieve real-time information on the session, and to guarantee QoS for each session based on priority levels and the user profile. Such functions allow carriers to provision the maximum usage of the bandwidth by managing, via the residential gateway, the customer's bandwidth. Along these lines, the carrier may collect information on the traffic within the home network so that the ISP can offer a personalized package based on the traffic patterns of the user. [0022] The present invention further provides an end-to-end QoS architecture that may manage several network segments. Similarly, auto learning mechanisms in the control plane of the present invention enable graceful termiantion of sessions for avoiding the delivery of rejected traffic to critical customer device ports. [0000] I. Architecture [0023] Refering now more specifically to FIG. 1 , a network diagram, including the architecture of the present invention, generally designated 5 , is shown. The network 10 is a wide area network, in the exemplary embodiment netowork 10 is the Internet. While network 10 is shown as a single cloud, of course, WAN network 10 may include sub-nets and component networks which are not depicted in FIG. 1 for the sake of simplicity and clarity of explanation. Likewise, network 10 can be a Local Area network (LAN). The network 10 includes a multitude of devices, routers, hosts etc. However, only core routers 12 and edge routers 14 are illustrated in FIG. 1 for exhibiting the high level functionality of the network 10 as a delivery medium. The monitoring and management of traffic in accordance with the present invention is between edge router 14 and customer premises 20 . [0024] Customer premises 20 may be a home network or enterprise network providing a CPE interface between a user and the edge of network 10 . In this regard, customer premises 20 may include a co-located gateway 22 or similar CPE device. Of course, those skilled in the art will recognize that the exact location of gateway 22 is not limited to any specific physical location. [0025] In the exemplary embodiment, the CPE is a gateway 22 of a residential home network. Those skilled in the art will recognize that CPE is not limited to gateway 22 and may instead be a Digital Subscriber Line (DSL) interface, a DOCSIS compliant device such as a cable modem, or an integrated device such as a set-top box including Microsoft® Media Center PC or Xbox 360®. Such devices may be configured to provide the same functionality of gateway 22 , namely, managing connectivity between a plurality of active data stream sessions. [0026] In the exemplary embodiment of FIG. 1 , customer preimses 20 includes an Ethernet local area network (LAN) 26 for interconnecting customer devices, generally designated 24 . The customer premises 20 in accordance with the present invention is not limited to any specific LAN technology, and, those skilled in the art will recognize that alternative hard wire and wireless technologies exist which will perform the same function and in the same manner, such as token ring, serial connection, USB, BlueTooth®, Wi-Fi, WiMax, cellular technologies, radio frequency (RF), infrared and the like. Likewise, the customer premises 20 may not employ any LAN at all, simply provide connectivity to a single customer device 24 . Customer devices 24 are generally depicted for the purposes of expressing the broad scope of devices that may be found in such an enterprise or home environement, including PDAs, PCs, Internet Appliances, cell phones, media centers and the like. [0027] In an alternative embodiment, the customer premises 20 is operably linked to a profile server 30 for distributing user profiles to gateway 22 . The server 30 , while shown separate from customer premises 20 , may be resident with in LAN 26 , likewise, identical functionality may be provided by an Internet Service provider (ISP) of network 10 . When situated external to the LAN and under control of an ISP, a security negotiation may be performed prior to the distribution or modification of user profiles resident on gateway 22 . This security negotiation may be performed transparent to the user via an automatic updating mechanism for example. The implementation of encryption/authentication mechanisms for performing this negotiation are known to those skilled in the art. The server 30 enables carriers of network 10 to provision the maximum usage of the bandwidth by managing, via the gateway 22 , the customer's bandwidth. Along these lines, the carrier may collect information on the traffic within the customer premises 20 so that personalized service packages based on the traffic patterns of the user can be provided. [0028] The server 30 is separately depicted for describing its functionality only, and those skilled in the art will recognize that the server functionality to the extent it is desired may be provided by alternative devices and at alternative locations. In the exemplary embodiment, the functionality of server 30 is integrated in a command line interface of the gateway 22 , and/or provided by customer devices 24 for defining user profiles as described further herein. [0029] Referring more specifically to FIG. 2 , a high level block diagram of the exemplary gateway 22 . The gateway 22 includes connectivity module 32 , a guardian control module 34 , memory 38 and customer side interface 36 . The gateway 22 communicates traffic from its customer side (upstream) to a downstream side of gateway 22 (shown in FIG. 3 ) via IPV 4 or IPV 6 in accordance with the TCP/IP protocol stack; those skilled in the art will recognize that alternative networking technologies are likewise embraced by the teachings of the present invention. [0030] The connectivity module 32 generally provides the behavior outlined above for presenting an access point to the edge of network 10 . In the exemplary embodiment, the connectivity module is cable modem which operates in accordance with the DOCSIS protocol. [0031] The guardian control module 34 provides additional functionality to the connectivity module 32 . In the exemplary embodiment, the guardian control module 34 functionality is performed by a software instruction set of a data processor (not shown). The instruction set may be in the form of application software and/or software drivers ported to the operating system of the gateway 22 . In alternative embodiments, the guardian control module 34 may be embodied in firmware, programmable logic, via an Application Specific Integrated Circuit (ASIC). [0032] Memory 38 may be integrated with the operation of guardian control module 34 via a scratchpad memory of a data processor of gateway 22 . Similarly, memory 38 may be a separate volatile or non-volatile memory. The memory 38 is provided for storing user profiles 40 a and session data 42 a . In an alternative embodiment, memory 38 may further store authentication data (not shown) for negotiating access to user profiles 40 a and session data 42 a via server 30 . Memory 38 is separately illustrated to represent functionality only; those skilled in the art recognize that the separate depiction in no way limits the implementation of the memory as a stand alone implementation of gateway 22 . For example, memory 38 may be physically separate from gateway 22 , or, resident at server 30 or a customer device 20 . [0033] The exemplary customer side interface 36 is an Ethernet switch for managing the delivery of traffic to one or more customer devices 20 of LAN 26 . Those skilled in the art recognize that the customer side interface 36 is not limited to any specific LAN technology. Likewise, customer side interface 36 may provide non-LAN connectivity such as serial ports. [0000] II. Control Functionality [0034] Referring now more specifically to FIG. 3 , a more detailed block diagram of guardian control module 34 is shown. The guardian control module 34 includes a bi-directional traffic shaper (BTS) 46 , an Application Killer (AP) 44 , policy database (including user profiles 40 a , control session dictionary (CSD) 42 (including session data 42 a ). [0035] FIG. 3 illustrates the functionality of guardian control module 34 interoperation with portions of memory 38 (CSD 42 and PD 40 ). The BTS 46 and Application Killer 44 , although illustrated as individual executable components, may be agents of the same instruction set. Alternatively, the BTS 46 and/or AK 44 may be embodied in the form of individual software drivers of gateway 22 . [0036] The BTS 46 is a QoS policy enforcement point for both upstream and downstream traffic relative to the edge of network 10 and customer premises 20 . The BTS 46 is the point of action/coordination between PD 40 , AK 44 , and CSD 42 . The BTS 46 performs bi-directional state-full Layer 2-to-Layer 7 traffic shaping. [0037] The BTS 46 communicates with PD 40 and user profiles 40 a therein, to retrieve QoS policy for each service before establishing a requested session. If the required QoS for a new session is not available and if the session is a higher priority relative to an active session, the BTS 46 utilizes the AK 44 to terminate the already existing session of lower priority. Where a new session is requested to be established, if the new session is of lower priority relative to existing sessions based on a user defined profile, and/or a required QoS is not available, then the session may not be established. [0038] Likewise, the BTS 46 can manage and control active session based on a group of user defined metrics to maintain a QOS for active sessions even when new requests are absent. For example, established active sessions may be terminated when they exceed certain user defined traffic metrics CSD 42 provides the control signals to stop the session based on data stored therein. The AK 44 cooperates with the BTS 46 to stop the active sessions by sending control messages to the source or sink of the stream (i.e., active session). AK 44 gets information about control messages and parameters from CSD 42 through BTS 46 . [0039] The policy database 40 is embodied in memory 38 and is a repository of QoS policy for all the possible services offered and also contains all the user profiles 40 a . It helps BTS 46 in prioritizing the active sessions. PD 40 may be populated via server 30 of the network 10 . The policy database 40 is accessed by the guardian control module 34 to provide the customer premises QOS management in accordance with the present invention. The exemplary user profile 40 a of policy database 40 includes a policy data hierarchy which classifies priorities of traffic in accordance with user preferences. The exemplary hierarchy employs weighted values for identifying a traffic flow (i.e., session) of a higher importance to the user relative to others. Such a weighting system can assign a high priority to VOIP or video streamed traffic as opposed to FTP traffic. [0040] Additionally, the exemplary policy data base 40 and user profiles 40 a stored therein, may include further policy data such as session QoS parameters, maximum tolerable delay, minimum throughput, maximum variance of the delay (jitter), etc. In this way, a determination can be made by the guardian control module 34 as to whether a newly requested session can be supported by the network 10 based on this additional policy data of user profile 40 : (a) by either the network providing sufficient capacity or resources to support the QoS, or (b) by dropping some lower priority session to accommodate the QoS requirements of the higher priority session. [0041] The session data control information is used to tear down the session. The CSD 42 is a group of parameter sets such as session data 42 a which are stored in the memory 38 for users and accessed by the guardian control module 34 to provide the customer premises QOS management in accordance with the present invention. The session data 42 a is a parameter set stored in memory 38 to identify details of active sessions of traffic being exchanged through the gateway 22 . The session data includes connection control data in state-full fashion. The CSD 42 may be populated externaly, for example by a server 30 of the network 10 , or through a CLI of gateway 22 . [0000] III. Operation [0042] Any processes descriptions or blocks in flow charts should be understood as representing modules, segments, portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process, and alternate implementations are included within the scope of the exemplary embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending upon the functionality involved, as would be understood by those skilled in the art. [0043] The flowchart of FIG. 4 describes the operation of the session establishment and termination for the guardian control module 34 . Initially, the BTS 46 receives a session or service request to accommodate new upstream or downstream user traffic at step 2 . The BTS 46 then retrieves the user profile 40 a corresponding to the newly requested session from the PD at step 4 . At step 6 , a determination is made whether the BTS 46 can support the newly requested session. If, for example, the required QoS can be supported, then the BTS 46 updates the CSD 42 with the sessions parameters at step 8 , and, allows the requested session at step 10 . If, on the other hand, the BTS 46 cannot support the required QoS, a determination is then made at step 12 whether there are any active lower priority sessions in the CSD 42 that may be terminated to allow the new session. If such a lower priority session exists, then a request is made to the AK 44 to clear the lower priority session from the CSD 42 , and allow the higher priority requesting session at step 16 . If however there are no such lower priority sessions in the CSD 42 , the requested session is terminated at step 14 . [0044] In an alternative embodiment, the AK 44 includes intelligence to update the PD 40 to respond to new requests from the end user in modifying the user profile 40 a , and the CSD 42 stores all the sessions data for upload to a network server as shown in the flowchart of FIG. 5 . [0045] Referring now to the flow chart of FIG. 5 , initially, the BTS receives session or service requests to accommodate new upstream or downstream user traffic at step 20 . The BTS 46 then retrieves the user profile 40 a for the newly requested session from the PD 40 at step 22 . A determination is made at step 24 whether the BTS 46 can support the newly requested session. If, for example the required QoS can be suported, then the BTS 46 updates the CSD 42 with the newly requested session parameters at step 26 , and allows the requested session at step 28 . If the BTS 46 cannot support the required QoS of the session, then a determination is made at step 30 whether there are any lower priority sessions in the CSD 42 that may be dropped. If there are lower priority sessions in the CSD 42 , a determination is then made whether the customer is willing to keep this low priority session at step 32 . If the customer is not willing to keep this low priority session, at step 34 , a request is made to the AK 44 to clear the lower priority session, and, at step 36 , a request is made to the the BTS 46 to update the CSD 42 with respect to the cleared session. If however the customer is willing to keep the low priority session at step 32 , a determination is then made if the customer is willing to pay for higher bandwidth at step 38 . If not, the requested session is terminated at step 40 . However, if the customer is willing to pay for higher bandwidth, the requested bandwidth is allocated to the new session at step 42 . [0046] Obviously, readily discernible modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. For example, while described in one or both of software and hardware components interactively cooperating, it is contemplated that the system described herein may be practiced entirely in software. The software may be embodied in a carrier such as magnetic or optical disk, or a radio frequency or audio frequency carrier wave. [0047] Thus, the foregoing discussion discloses and describes merely exemplary embodiment of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting of the scope of the invention, as well as other claims. The disclosure, including any readily discernible variants of the teachings herein, define, in part, the scope of the foregoing claim terminology such that no inventive subject matter is dedicated to the public.

A customer premises device is provided for monitoring quality of service (QOS) metrics between a network edge and a customer. The device includes a memory which stores at least one user profile, and, information regarding active sessions of traffic flow through the customer premises device. A hardware and/or software/firmware based controller monitors traffic flow between the customer and the network edge and receives requests for new active sessions. The processor accesses the at least one user profile stored in memory to identify a policy hierarchy with respect to active sessions of traffic flow upon receipt of a request to establish a new active session. The processor selects a candidate active session to be terminated based upon the policy hierarchy and terminates the selected session in accordance with information stored in memory regarding the selected session. In this manner, the processor enforces quality of service, for both upstream and downstream sessions, based upon the policy hierarchy of the user profile.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The inventive subject matter relates to substituted diaminopyrimidine compounds, which are effective therapeutic compounds for treating diseases and disorders associated with those commonly treated by Protein Kinase C theta (PKCθ) inhibitors. [0003] 2. Description of Related Art [0004] In International Patent Application WO 99/65881, 6-membered heterocyclic compounds are disclosed which are said to be useful as hypoglycemic agents. International Patent Application WO 00/39108 discloses aromatic heterocyclic compounds, which are said to be useful as thrombin or factor Xa inhibitors. In International Patent Application WO 00/39101, pyrimidine compounds are disclosed which are said to be useful as anti-cancer agents. International Patent Application WO 01/00214 discloses pyrimidines, which are said to be useful as SRC kinase inhibitor compounds. In U.S. Pat. No. 6,159,982 2,4-diaminopyrimidine derivates are described as dopamine D4 receptor antagonists. BRIEF SUMMARY OF THE INVENTION [0005] It has now been found that the compounds of the formula 1, which are described in more detail below, possess surprising and particularly advantageous properties. [0006] One embodiment of the inventive subject matter relates to compounds of the formula 1, in which R1 is a mono- or bicyclic aromatic radical substituted by R11, R12, R13 and R14, wherein R1 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R11 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, or together with R12 methylenedioxy or ethylenedioxy, R12 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, or together with R11 methylenedioxy or ethylenedioxy, R13 is hydrogen, 1-4C-alkyl or halogen and R14 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R2 is a mono- or bicyclic aromatic radical substituted by R21, R22, R23 and R24, wherein R2 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R21 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, or together with R22 methylenedioxy or ethylenedioxy, R22 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, or together with R21 methylenedioxy or ethylenedioxy, R23 is hydrogen, 1-4C-alkyl or halogen and R24 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R3 is a mono- or bicyclic aromatic radical substituted by R31, R32, R33 and R34, wherein R3 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R31 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, or together with R32 methylenedioxy or ethylenedioxy, R32 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, or together with R31 methylenedioxy or ethylenedioxy, R33 is hydrogen, 1-4C-alkyl or halogen and R34 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R4 is hydrogen or methyl, R5 is hydrogen or methyl, A1 is 1-3C-alkylene or ethyleneoxy (—CH 2 —CH 2 —O—) and A2 is 1-3C-alkylene or ethyleneoxy (—CH 2 —CH 2 —O—), and their salts. [0034] Another embodiment of the inventive subject matter relates to a pharmaceutical composition comprising a compound of the above formula and/or a pharmaceutically acceptable salt thereof together with pharmaceutically acceptable excipients and/or carrier. [0035] A further embodiment of the inventive subject matter relates to a method of treating a patient afflicted with a disease or disorder, comprising the step of administering a therapeutically effective amount of a compound as described above and/or a pharmaceutically acceptable salt thereof to said patient afflicted with said disease or disorder, wherein the disease is selected from the group of acute and/or chronic airway disorders, inflammatory or allergen-induced airway disorder, bronchitis, obstructive bronchitis, spastic bronchitis, allergic bronchitis, allergic asthma, bronchial asthma, emphysema, chronic obstructive pulmonary disease (COPD), a disorder which is based on an excessive release of T-Cell derived cytokines, HIV-infection, septic shock, adult respiratory distress syndrome, graft-versus-host reactions, acute or chronic rejection of organ or tissue allo- or xenografts, generalized inflammations in the gastrointestinal area, rheumatoid arthritis, rheumatoid spondylitis, osteoarthritis, allergic and/or chronic, faulty immunological reactions in the area of the upper airways and the adjacent regions, dermatose of the proliferative, inflammatory or allergic type, psoriasis (vulgaris), toxic and allergic contact eczema, atopic eczema, seborrheic eczema, lichen simplex, sunburn, pruritus in the anogenital area, alopecia areata, hypertrophic scars, discoid lupus erythematosus, follicular and vide-area pyodermias, endogenous and exogenous acne, acne rosacea, other proliferative, inflammatory, allergic skin disorders, a disorder in connection with disturbances of brain metabolism or alternatively disorders of the central nervous system (CNS), cerebral senility, senile dementia, multiinfarct dementia, depression, arteriosclerotic dementia, cancer and diabetes insipidus. [0036] A still further embodiment of the inventive subject matter relates to a process for preparing a compound of formula 1 as described above or a salt thereof, which comprises reacting a boronic acid derivative R1-B(OH) 2 wherein R1 has the meaning specified above, with a pyrimidine derivate of formula (4) in which A1, A2, R2, R3, R4 and R5 have a meaning specified above, and optionally converting an obtained compound into a corresponding salt or converting an obtained salt into a corresponding free compound. DETAILED DESCRIPTION OF THE INVENTION [0000] Definitions [0037] The following terms are used herein to have the indicated meanings and are capable of including additional components well known to one of ordinary skill in the art. [0038] 1-4C-Alkyl represents straight-chain or branched alkyl radicals having 1 to 4 carbon atoms. Examples which may be mentioned are the butyl, isobutyl, sec-butyl, tert-butyl, propyl, isopropyl, ethyl and the methyl radical. [0039] Hydroxy-1-4C-alkyl represents aforementioned 1-4C-alkyl radicals, which are substituted by a hydroxy group. Examples which may be mentioned are the hydroxymethyl, the 2-hydroxyethyl and the 3-hydroxypropyl radical. [0040] 1-4C-Alkoxy represents radicals, which in addition to the oxygen atom contain a straight-chain or branched alkyl radical having 1 to 4 carbon atoms. Examples which may be mentioned are the butoxy, isobutoxy, sec-butoxy, tert-butoxy, propoxy, isopropoxy and preferably the ethoxy and methoxy radical. [0041] 2-4C-Alkenyl represents straight-chain or branched alkenyl radicals having 2 to 4 carbon atoms. Examples which may be mentioned are the 2-butenyl, 3-butenyl, 1-propenyl and the 2-propenyl radical (allyl radical). [0042] 2-4C-Alkenyloxy represents a radical, which in addition to the oxygen atom contains a 2-4C-alkenyl radical. An example which may be mentioned is the allyloxy radical. [0043] 1-4C-Alkylcarbonyl represents a radical, which in addition to the carbonyl group contains one of the aforementioned 1-4C-alkyl radicals. An example which may be mentioned is the acetyl radical. [0044] Carboxyl is the group —COOH. [0045] Aminocarbonyl is Amino (—NH 2 ) which is bound to the carbonyl group, i.e. aminocarbonyl is —CO—NH 2 . Mono- or di-1-4C-alkylamino radicals contain, in addition to the nitrogen atom, one or two of the aforementioned 1-4C-alkyl radicals. Di-1-4C-alkylamino is preferred and here, in particular, dimethyl-, diethyl or diisopropylamino. [0046] Mono- or di-1-4C-alkylaminocarbonyl represents a radical, which in addition to the carbonyl group contains one of the aforementioned mono- or di-1-4C-alkylamino radicals. [0047] 1-4C-Alkoxycarbonyl represents a carbonyl group, to which one of the aforementioned 1-4C-alkoxy radicals is bonded. Examples which may be mentioned are the methoxycarbonyl (CH 3 O—C(O)—) and the ethoxycarbonyl radical (CH 3 CH 2 O—C(O)—). [0048] Carboxy-1-4C-alkyl for example represents the carboxymethyl (—CH 2 COOH) or the carboxyethyl radical (—CH 2 CH 2 COOH). [0049] 1-4C-Alkoxycarbonyl-1-4C-alkyl represents one of the aforementioned 1-4C-alkyl radicals, which is substituted by one of the aforementioned 1-4C-alkoxycarbonyl radicals. An example which may be mentioned is the ethoxycarbonylmethyl radical (CH 3 CH 2 OC(O)CH 2 —). [0050] Halogen within the meaning of the invention is bromo, chloro and fluoro. [0051] Aryl-1-4C-alkyl represents an aryl-substituted 1-4C-alkyl radical. An example which may be mentioned is the benzyl radical. [0052] Aryl-1-4C-alkoxy represents an aryl-substituted 1-4C-alkoxy radical. An example which may be mentioned is the benzyloxy radical. [0053] 1-4C-Alkylcarbonylamino represents an amino group to which a 1-4C-alkylcarbonyl radical is bonded. Examples which may be mentioned are the propionylamino (C 3 H 7 C(O)NH—) and the acetylamino radical (acetamido radical) (CH 3 C(O)NH—). [0054] 1-4C-Alkoxycarbonylamino represents an amino radical, which is substituted by one of the aforementioned 1-4C-alkoxycarbonyl radicals. Examples which may be mentioned are the ethoxycarbonylamino and the methoxycarbonylamino radical. [0055] 1-4C-Alkoxy-1-4C-alkoxy represents one of the aforementioned 1-4C-alkoxy radicals, which is substituted by a further 1-4C-alkoxy radical. Examples which may be mentioned are the radicals 2-(methoxy)ethoxy (CH 3 —O—CH 2 —CH 2 —O—) and 2-(ethoxy)ethoxy (CH 3 —CH 2 —O—CH 2 —CH 2 —O—). [0056] 1-4C-Alkoxy-1-4C-alkoxycarbonyl represents a carbonyl group, to which one of the aforementioned 1-4C-alkoxy-1-4C-alkoxy radicals is bonded. Examples which may be mentioned are the 2-(methoxy)-ethoxycarbonyl (CH 3 —O—CH 2 CH 2 —O—CO—) and the 2-(ethoxy)ethoxycarbonyl radical (CH 3 CH 2 —O—CH 2 CH 2 —O—CO—). [0057] 1-4C-Alkoxy-1-4C-alkoxycarbonylamino represents an amino radical, which is substituted by one of the aforementioned 1-4C-alkoxy-1-4C-alkoxycarbonyl radicals. Examples which may be mentioned are the 2-(methoxy)ethoxycarbonylamino and the 2-(ethoxy)ethoxycarbonylamino radical. [0058] In case that R11 together with R12, or R21 together with R22, or R31 together with R32 form a methylenedioxy (—O—CH 2 —O—) or ethylenedioxy (—O—CH 2 CH 2 —O—) group, it is necessary that R11 and R12, or R21 and R22, or R31 and R32 are in adjacent positions to each other (ortho-position). [0059] 1-3C-Alkylene represents straight-chain or branched 1-3C-alkylene radicals, for example the methylene (—CH 2 —), ethylene (—CH 2 CH 2 —), ethylidene [—CH(CH 3 )—], trimethylene (—CH 2 CH 2 CH 2 —), isopropylidene [—C(CH 3 ) 2 —] and the 1-methylethylene [—CH(CH 3 )—CH 2  ] radical. [0060] The compounds according to the invention have valuable pharmacological properties, which make them commercially utilizable. In one possible mode of action they may act as selective Protein Kinase C theta (PKCθ) inhibitors. As such they are suitable as therapeutics especially for the treatment of disorders, in particular of inflammatory nature, e.g. of the airways (asthma prophylaxis), of the skin, of the central nervous system, of the intestine, of the eyes and of the joints, which are mediated by T-cells and derived mediators such as cytokines, interleukins, chemokines, alpha-, beta- and gamma-interferon or tumor necrosis factor (TNF). The compounds according to the invention are distinguished here by low toxicity, good enteral absorption (high bioavailability), a large therapeutic breadth and the absence of significant side-effects. [0061] On account of their PKC-inhibiting properties, the compounds according to the invention can be employed in human and veterinary medicine and therapeutics, where they can be used, for example, for the treatment and prophylaxis of the following illnesses: acute and chronic (in particular inflammatory and allergen-induced) airway disorders of various origins (bronchitis, obstructive bronchitis, spastic bronchitis, allergic bronchitis, allergic asthma, bronchial asthma, emphysema, COPD); dermatoses (especially of proliferative, inflammatory and allergic type) such as, for example, psoriasis (vulgaris), toxic and allergic contact eczema, atopic eczema, seborrheic eczema, lichen simplex, sunburn, pruritus in the anogenital area, alopecia areata, hypertrophic scars, discoid lupus erythematosus, follicular and wide-area pyodermias, endogenous and exogenous acne, acne rosacea and other proliferative, inflammatory and allergic skin disorders; disorders which are based on an excessive release of T-cell derived cytokines, e.g. disorders of the arthritis type (rheumatoid arthritis, rheumatoid spondylitis, osteoarthritis and other arthritic conditions), disorders of the immune system (AIDS, multiple sclerosis), HIV-infection, septic shock or adult respiratory distress syndrome, graft-versus-host reactions, acute or chronic rejection of organ or tissue allo- or xenografts, and generalized inflammations in the gastrointestinal area (Crohn's disease and ulcerative colitis); disorders which are based on allergic and/or chronic, faulty immunological reactions in the area of the upper airways (pharynx, nose) and the adjacent regions (paranasal sinuses, eyes), such as, for example, allergic rhinitis/sinusitis, chronic rhinitis/sinusitis, allergic conjunctivitis and nasal polyps autoimmune disorders involving various tissues (e.g. kidney, pancreas, thyroidea, skin or joints). In addition, the compounds according to the invention can be employed for the treatment of cancer, diabetes insipidus and disorders in connection with disturbances of brain metabolism, such as, for example, cerebral senility, senile dementia (Alzheimer's dementia), multiinfarct dementia or alternatively disorders of the CNS, such as, for example, depressions or arteriosclerotic dementia. [0062] The compounds according to the invention may be administered as the sole active ingredient or together, i.e. in a fixed or free combination, with other therapeutic agents used in clinical practice for the treatment of those diseases listed above. Reference is made in this connection to other drugs in immunomodulating regimens or other anti-inflammatory agents e.g. for the treatment or prevention of inflammatory or autoimmune disorders or allo- or xenograft acute or chronic rejection. For example, the compounds of formula 1 may be used in combination with cyclosporines or ascomycines or their immunosuppressive analogs or derivatives; an mTOR inhibitor, corticosteroids; cyclophosphamide; azathioprene; methotrexate; an accelerating lymphocyte homing agent; leflunomide or analogs thereof, mizoribine; mycophenolic acid; mycophenolate mofetil; 15-deoxyspergualine or analogs thereof; immunosuppressive monoclonal antibodies, e.g. monoclonal antibodies to leukocyte receptors or their ligands; or other immunomodulatory compounds, e.g. a recombinant binding molecule or portions of it e.g. CTLA4 or other adhesion molecule inhibitors, e.g. mAbs or low molecular weight inhibitors including LFA-1 antagonists, Selectin antagonists and VLA-4 antagonists. Compounds according to this invention may also be administered together with an anti-proliferative drug, e.g. a chemotherapeutic drug, e.g. in cancer treatment, or with an anti-diabetic drug in diabetes treatment. [0063] The invention further relates to the compounds according to the invention for use in the treatment of mammals, including man, which are suffering from one of the abovementioned illnesses. The process comprises administering to the sick mammal a therapeutically efficacious and pharmacologically tolerable amount of one or more of the compounds and/or a pharmaceutically acceptable salt thereof according to the invention. [0064] The invention further relates to the compounds according to the invention for use in the treatment and/or prophylaxis of illnesses, in particular the illnesses mentioned. [0065] The invention likewise relates to the use of the compounds according to the invention for the production of pharmaceutical compositions which are employed for the treatment and/or prophylaxis of the illnesses mentioned. [0066] Pharmaceutical compositions for the treatment and/or prophylaxis of the illnesses mentioned, which contain one or more of the compounds according to the invention, are furthermore a subject of the invention. [0067] The inventive subject matter relates to compounds of the formula 1, in which R1 is a mono- or bicyclic aromatic radical substituted by R11, R12, R13 and R14, wherein R1 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R11 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, or together with R12 methylenedioxy or ethylenedioxy, R12 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, or together with R11 methylenedioxy or ethylenedioxy, R13 is hydrogen, 1-4C-alkyl or halogen and R14 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R2 is a mono- or bicyclic aromatic radical substituted by R21, R22, R23 and R24, wherein R2 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R21 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, or together with R22 methylenedioxy or ethylenedioxy, R22 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, or together with R21 methylenedioxy or ethylenedioxy, R23 is hydrogen, 1-4C-alkyl or halogen and R24 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R3 is a mono- or bicyclic aromatic radical substituted by R31, R32, R33 and R34, wherein R3 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R31 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, or together with R32 methylenedioxy or ethylenedioxy, R32 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, or together with R31 methylenedioxy or ethylenedioxy, R33 is hydrogen, 1-4C-alkyl or halogen and R34 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R4 is hydrogen or methyl, R5 is hydrogen or methyl, A1 is 1-3C-alkylene or ethyleneoxy (—CH 2 —CH 2 —O—) and A2 is 1-3C-alkylene or ethyleneoxy (—CH 2 —CH 2 —O—), and their salts. [0095] Another embodiment of the Inventive subject matter relates to a compound of formula 1, [0000] in which [0000] R1 is a mono- or bicyclic aromatic radical substituted by R11, R12, R13 and R14, wherein R1 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R11 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, R12 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, R13 is hydrogen, 1-4C-alkyl or halogen and R14 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R2 is a mono- or bicyclic aromatic radical substituted by R21, R22, R23 and R24, wherein R2 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R21 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, R22 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, R23 is hydrogen, 1-4C-alkyl or halogen and R24 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R3 is a mono- or bicyclic aromatic radical substituted by R31, R32, R33 and R34, wherein R3 is selected from the group consisting of phenyl, naphthyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, indolyl, benzimidazolyl, furanyl (furyl), benzofuranyl(benzofuryl), thiophenyl(thienyl), benzothiophenyl (benzothienyl), thiazolyl, isoxazolyl, pyridinyl, pyrimidinyl, quinolinyl and isoquinolinyl, where R31 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, aryl, aryl-1-4C-alkyl, aryloxy, aryl-1-4C-alkoxy, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, R32 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl or hydroxyl, R33 is hydrogen, 1-4C-alkyl or halogen and R34 is hydrogen, 1-4C-alkyl or halogen, where aryl is phenyl or substituted phenyl having one, two or three substituents selected from the group consisting of 1-4C-alkyl, 1-4C-alkoxy, carboxyl, 1-4C-alkoxycarbonyl, halogen, trifluoromethyl, nitro, trifluoromethoxy, hydroxyl, cyano and mixtures thereof, R4 is hydrogen, R5 is hydrogen, A1 denotes 1-3C-alkylene and A2 denotes 1-3C-alkylene, and their salts. [0123] An embodiment of the inventive subject matter, to be emphasized is a compound of formula 1, [0000] in which [0000] R1 is an aromatic radical substituted by R11, R12, R13 and R14, wherein R1 is selected from the group consisting of phenyl, furanyl (furyl) and thiophenyl(thienyl), where R11 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, or together with R12 methylenedioxy or ethylenedioxy, R12 is hydrogen or halogen, or together with R11 methylenedioxy or ethylenedioxy, R13 is hydrogen and R14 is hydrogen, R2 is an aromatic radical substituted by R21, R22, R23 and R24, wherein R2 is selected from the group consisting of pyridinyl and pyrimidinyl, where R21 is hydrogen, 1-4C-alkyl, 1-4C-alkoxy or halogen, R22 is hydrogen or halogen, R23 is hydrogen and R24 is hydrogen, R3 is an aromatic radical substituted by R31, R32, R33 and R34, wherein R3 is selected from the group consisting of phenyl and pyridinyl, where R31 is hydrogen, 1-4C-alkyl, hydroxy-1-4C-alkyl, 1-4C-alkoxy, 2-4C-alkenyloxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkoxycarbonyl, carboxy-1-4C-alkyl, 1-4C-alkoxycarbonyl-1-4C-alkyl, halogen, hydroxyl, trifluoromethyl, nitro, amino, mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, 1-4C-alkoxycarbonylamino, 1-4C-alkoxy-1-4C-alkoxycarbonylamino or sulfonyl, R32 is hydrogen or halogen, R33 is hydrogen and R34 is hydrogen, R4 is hydrogen or methyl, R5 is hydrogen or methyl, A1 is 1-3C-alkylene or ethyleneoxy (—CH 2 —CH 2 —O—) and A2 is 1-3C-alkylene or ethyleneoxy (—CH 2 —CH 2 —O—), and their salts. [0145] An embodiment of the inventive subject matter to be particularly emphasized, is a compound of formula 1, [0000] in which [0000] R1 is an aromatic radical substituted by R11, R12, R13 and R14, wherein R1 is selected from the group consisting of phenyl, furanyl (furyl) and thiophenyl(thienyl), where R11 is hydrogen, 1-4C-alkoxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, halogen, hydroxyl or mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, or together with R12 methylenedioxy or ethylenedioxy, R12 is hydrogen or halogen, or together with R11 methylenedioxy or ethylenedioxy, R13 is hydrogen and R14 is hydrogen, R2 is an aromatic radical substituted by R21, R22, R23 and R24, wherein R2 is selected from the group consisting of pyridinyl and pyrimidinyl, where R21 is hydrogen, R22 is hydrogen, R23 is hydrogen and R24 is hydrogen, R3 is an aromatic radical substituted by R31, R32, R33 and R34, wherein R3 is selected from the group consisting of phenyl and pyridinyl, where R31 is hydrogen, 1-4C-alkoxy or halogen, R32 is hydrogen, R33 is hydrogen and R34 is hydrogen, R4 is hydrogen or methyl, R5 is hydrogen or methyl, A1 denotes methylene, ethylene, ethylidene [—CH(CH 3 )—] or ethyleneoxy (—CH 2 —CH 2 —O—) and A2 denotes methylene, ethylene, ethylidene [—CH(CH 3 )—] or ethyleneoxy (—CH 2 —CH 2 —O—), and their salts. [0168] Selected compounds of formula 1 are those, [0000] in which [0000] R1 is furanyl (furyl), thiophenyl(thienyl) or phenyl substituted by R11 and R12, where R11 is hydrogen, 1-4C-alkoxy, carboxyl, aminocarbonyl, halogen or di-1-4C-alkylamino and R12 is hydrogen, R2 is pyridinyl, R3 is phenyl, R4 is hydrogen, R5 is hydrogen, A1 denotes methylene and A2 denotes methylene, and their salts. [0179] Further selected compounds of formula 1 are those, [0000] in which [0000] R1 is furanyl (furyl), thiophenyl(thienyl) or phenyl substituted by R11 and R12, where R11 is hydrogen, 1-4C-alkoxy, 1-4C-alkylcarbonyl, carboxyl, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, halogen, hydroxyl or mono- or di-1-4C-alkylamino, 1-4C-alkylcarbonylamino, or together with R12 methylenedioxy or ethylenedioxy, R12 is hydrogen or halogen, or together with R11 methylenedioxy or ethylenedioxy, R2 is pyridinyl, R3 is phenyl, R4 is hydrogen, R5 is hydrogen, A1 denotes methylene and A2 denotes methylene, and their salts. [0190] Exemplary substituents R1 are: 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, phenyl, 4-methoxyphenyl, 4-chlorophenyl, 4-dimethylaminophenyl, 4-aminocarbonylphenyl, 4-carboxyphenyl, 3-chloro-4-fluorophenyl, 3-acetylaminophenyl, benzo[1,3]dioxol-5-yl, 3-hydroxyphenyl, 4-hydroxyphenyl, 4-acetylphenyl, 3-acetyl-phenyl, 4-acetylaminophenyl, 4-dimethylaminocarbonyl-phenyl and 4-aminocarbonylphenyl. [0191] In a preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein R1 is furanyl (furyl), thiophenyl(thienyl) or phenyl substituted by R11 and R12, where R11 is hydrogen, 1-4C-alkoxy, carboxyl, aminocarbonyl, halogen or di-1-4C-alkylamino and R12 is hydrogen. [0192] In another preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein R1 is 2-furanyl or 3-furanyl. [0193] In a still preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein R1 is 2-thiophenyl or 3-thiophenyl. [0194] In another still preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein R1 is selected from the group of phenyl, 4-methoxyphenyl, 4-chlorophenyl, 4-dimethylaminophenyl, 4-aminocarbonylphenyl, 4-carboxyphenyl, 3-chloro-4-fluorophenyl, 3-acetylaminophenyl, benzo[1,3]dioxol-5-yl, 3-hydroxyphenyl, 4-hydroxyphenyl, 4-acetylphenyl, 3-acetylphenyl, 4-acetylaminophenyl, 4-dimethylaminocarbonyl-phenyl and 4-aminocarbonylphenyl. [0195] Exemplary substituents R2 are: 4-pyridyl, 2-pyridyl, 3-pyridyl and 4-pyrimidinyl. Amongst the pyridyl groups, the 2-pyridyl group is preferred. [0196] In another still preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein R2 is selected from the group of 4-pyridyl, 2-pyridyl, 3-pyridyl and 4-pyrimidinyl. [0197] Exemplary substituents A1-R2 are: 2-pyridylmethyl, 4-pyridylmethyl, 3-pyridylmethyl, 4-pyrimidinylmethyl, 2-pyridyl-1-ethyl, 2-pyridyl-2-ethyl, 3-pyridyl-2-ethyl, 4-pyrimidinyl-2-ethyl, 2-pyridyloxy-2-ethyl and 3-pyridyloxy-2-ethyl. [0198] In another still preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein A1-R2 is selected from the group of 2-pyridylmethyl, 4-pyridylmethyl, 3-pyridylmethyl, 4-pyrimidinylmethyl, 2-pyridyl-1-ethyl, 2-pyridyl-2-ethyl, 3-pyridyl-2-ethyl, 4-pyrimidinyl-2-ethyl, 2-pyridyloxy-2-ethyl and 3-pyridyloxy-2-ethyl. [0199] Exemplary substituents R3 are: phenyl, 4-fluorophenyl, 4-methoxyphenyl, and 4-pyridinyl. [0200] In another still preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein R3 is selected from the group of phenyl, 4-fluorophenyl, 4-methoxyphenyl, and 4-pyridinyl. [0201] Exemplary substituents A2-R3 are: benzyl, 4-fluorobenzyl, 4-methoxybenzyl, phenyl-1-ethyl, phenyl-2-ethyl and phenoxy-2-ethyl. [0202] In another still preferred embodiment the inventive subject matter relates to a compound of formula 1, wherein A2-R3 is selected from the group of benzyl, 4-fluorobenzyl, 4-methoxybenzyl, phenyl-1-ethyl, phenyl-2-ethyl and phenoxy-2-ethyl. [0203] The compounds according to the invention can be prepared as exemplary described in the paragraph “Examples” which follows below, or using analogous process steps starting from appropriate starting compounds. The compounds according to the invention can be prepared for example starting from appropriate 2,4,5-trihalopyrimidines, for example from 5-bromo-2,4-dichloropyrimidine, according to the following reaction scheme: [0204] 5-Bromo-2,4-dichloropyrimidine is reacted with the aminopiperidine 2 in a manner known per se. Advantageously, the reaction is carried out in an inert solvent at an appropriate temperature, such as room temperature, in the presence of a base (e.g. of an inorganic hydroxide, such as sodium hydroxide, or of an inorganic carbonate, such as potassium carbonate, or of an organic nitrogen base, such as triethylamine) or with an excess of compound 2. The subsequent reaction with the amine H 2 N-A1-R2 is likewise carried out in the presence of an auxiliary base or with an excess of the amine, preferably at temperatures higher than room temperature, e.g. between 60 and 150° C., in particular at the boiling point of the inert solvent used. The concluding reaction with the boronic acid R1-B(OH) 2 is also carried out in a manner known per se to the person skilled in the art and familiar with the Suzuki reaction, e.g. as outlined in the Examples which follow below. [0205] The starting compounds are known or can be prepared analogously to the known compounds. The substances according to the invention are isolated and purified in a manner known per se, for example, by distilling off the solvent in vacuo and recrystallizing the residue obtained from a suitable solvent or subjecting it to one of the customary purification methods, such as, for example, column chromatography on suitable support material. [0206] Salts are obtained by dissolving the free compound in a suitable solvent, e.g. in a chlorinated hydrocarbon, such as dichloromethane or chloroform, or a low molecular weight aliphatic alcohol (ethanol, isopropanol) which contains the desired acid, or to which the desired acid is subsequently added. The salts are obtained by filtering, reprecipitating, precipitating with a non-solvent for the addition salt or by evaporating the solvent. Salts obtained can be converted by alkalization or by acidification into the free compounds, which in turn can be converted into salts. In this way, salts pharmaceutically not acceptable can be converted into pharmaceutically acceptable salts. [0207] Possible salts of compounds of the formula 1—depending on substitution—are especially all acid addition salts. Particular mention may be made of the pharmaceutically acceptable salts of the inorganic and organic acids customarily used in pharmacy. Those suitable are water-soluble and water-insoluble acid addition salts with acids such as, for example, hydrochloric acid, hydrobromic acid, phosphoric acid, nitric acid, sulfuric acid, acetic acid, citric acid, D-gluconic acid, benzoic acid, 2-(4-hydroxybenzoyl)benzoic acid, butyric acid, sulfosalicylic acid, maleic acid, lauric acid, malic acid, fumaric acid, succinic acid, oxalic acid, tartaric acid, embonic acid, stearic acid, toluenesulfonic acid, methanesulfonic acid or 3-hydroxy-2-naphthoic acid, where the acids are used in salt preparation—depending on whether a mono- or polybasic acid is concerned and on which salt is desired—in an equimolar quantitative ratio or one differing therefrom. [0208] Salts, which are pharmaceutically not acceptable, which can initially be obtained, for example, as process products in the production of the compounds according to the invention on the industrial scale, are converted into the pharmaceutically acceptable salts by processes known to the person skilled in the art. [0209] It is known to the person skilled in the art that the compounds according to invention and their salts, if, for example, they are isolated in crystalline form, can contain various amounts of solvents. The invention therefore also comprises all solvates and in particular all hydrates of the compounds of the formula 1, and also all solvates and in particular all hydrates of the salts of the compounds of the formula 1. [0210] In case of A1 and/or A2 being ethylidene [—CH(CH 3 )—], the compounds of the formula 1 have one or two chiral centers. The invention relates to all four conceivable stereoisomers in any desired mixing ratio with one another, including the pure enantiomers, which are a preferred subject of the invention and which can be synthesized by using the corresponding optically pure starting compounds. [0211] A further subject of the invention is a commercial product, consisting of a customary secondary pack, a primary pack containing the pharmaceutical composition (for example an ampoule or a blister pack) and, if desired, a pack insert, the medicament exhibiting antagonistic action against Protein Kinase C theta (PKCθ) and leading to the attenuation of the symptoms of illnesses which are connected Protein Kinase C theta (PKCθ), and the suitability of the medicament for the prophylaxis or treatment of illnesses which are connected with Protein Kinase C theta (PKCθ) being indicated on the secondary pack and/or on the pack insert of the commercial product, and the medicament containing one or more compounds of the formula I according to the invention. The secondary pack, the primary pack containing the medicament and the pack insert otherwise comply with what would be regarded as standard to the person skilled in the art for pharmaceutical compositions of this type. [0212] The pharmaceutical compositions are prepared by processes, which are known per se and familiar to the person skilled in the art As pharmaceutical compositions, the compounds according to the invention (=active compounds) are either employed as such, or preferably in combination with suitable pharmaceutical excipients, e.g. in the form of tablets, coated tablets, capsules, suppositories, patches, emulsions, suspensions, gels or solutions, the active compound content advantageously being between 0.1 and 95%. [0213] The person skilled in the art is familiar on the basis of his/her expert knowledge with the excipients, which are suitable for the desired pharmaceutical formulations. In addition to solvents, gel-forming agents, ointment bases and other active compound vehicles, it is possible to use, for example, antioxidants, dispersants, emulsifiers, preservatives, solubilizers or permeation promoters. [0214] For the treatment of disorders of the respiratory tract, the compounds according to the invention are preferably also administered by inhalation in the form of an aerosol; the aerosol particles of solid, liquid or mixed composition preferably having a diameter of 0.5 to 10 μm, advantageously of 2 to 6 μm. [0215] Aerosol generation can be carried out, for example, by pressure-driven jet atomizers or ultrasonic atomizers, but advantageously by propellant-driven metered aerosols or propellant-free administration of micronized active compounds from inhalation capsules. [0216] Depending on the inhaler system used, in addition to the active compounds the administration forms additionally contain the required excipients, such as, for example, propellants (e.g. Frigen in the case of metered aerosols), surface-active substances, emulsifiers, stabilizers, preservatives, flavorings, fillers (e.g. lactose in the case of powder inhalers) or, if appropriate, further active compounds. [0217] For the purposes of inhalation, a large number of apparatuses are available with which aerosols of optimum particle size can be generated and administered, using an inhalation technique which is as right as possible for the patient. In addition to the use of adaptors (spacers, expanders) and pear-shaped containers (e.g. Nebulator®, Volumatic®), and automatic devices emitting a puffer spray (Autohaler®), for metered aerosols, in particular in the case of powder inhalers, a number of technical solutions are available (e.g. Diskhaler®, Rotadisk@, Turbohaler® or the inhaler described in European Patent Application EP 0 505 321), using which an optimal administration of active compound can be achieved. [0218] For the treatment of dermatoses, the compounds according to the invention are in particular used in the form of those pharmaceutical compositions, which are suitable for topical application. For the production of the pharmaceutical compositions, the compounds according to the invention (=active compounds) are preferably mixed with suitable pharmaceutical excipients and further processed to give suitable pharmaceutical formulations. Suitable pharmaceutical formulations, which may be mentioned are, for example, powders, emulsions, suspensions, sprays, oils, ointments, fatty ointments, creams, pastes, gels or solutions. [0219] Pharmaceutical compositions according to the invention can be prepared by processes known per se. Dosage of the active compounds takes place in the order of magnitude customary for PKCθ inhibitors. Thus topical application forms (such as, for example, ointments) for the treatment of dermatoses contain the active compounds in a concentration of, for example, 0.1-99%. The dose for administration by inhalation is customarily between 0.1 and 3 mg per day. The customary dose in the case of systemic therapy (p.o. or i.v.) is between 0.03 and 3 mg per kilogram per day. [0220] The following examples are illustrative of the present invention and are not intended to be limitations thereon. Likewise, further compounds of the formula 1 whose preparation is not described explicitly can be prepared analogously or in a manner familiar to the person skilled in the art using customary process techniques. The abbreviation ESMS stands for Electro Spray Mass Spectroscopy and eq stands for equivalent(s). EXAMPLES [0000] Final Products 1. [1-Benzyl(4-piperidyl)]{2-[(2-pyridylmethyl)amino]-5-(3-thienyl)pyrimidin-4-yl}amine [0221] 3-Thiopheneboronic acid (0.62 g, 4.85 mmol) was added to a solution of {5-bromo-2-[(2-pyridylmethyl)-amino]pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine (1.00 g, 2.21 mmol) in ethylene glycol dimethyl ether (50 mL). A solution of potassium carbonate (1.25 g, 9.04 mmol) in water (15 mL) was added to the above reaction mixture. Tetrakis(triphenylphosphine)palladium (260 mg, 0.225 mmol) was added to the reaction and stirred at 80° C. under nitrogen for 2 hours. The reaction mixture was diluted with water (150 mL) and extracted with methylene chloride (4×100 mL). The organic layer was concentrated and the residue was purified using flash chromatography (5% methanol in ethyl acetate) to give [1-benzyl(4-piperidyl)]{2-[(2-pyridylmethyl)amino]-5-(3-thienyl)pyrimidin-4-yl}amine (0.45 g, 45% yield) as an off-white foam; ESMS 457 (M+1) + . 2. {5-(4-Methoxyphenyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0222] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-methoxyphenyl boronic acid as described in Example 1 as an off-white foam; ESMS 481 (M+1) + . 3. {5-Phenyl-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0223] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, phenyl boronic acid as described in Example 1 as an off-white foam; ESMS 451 (M+1) + . 4. {5-(4-Chlorophenyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0224] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-chlorophenyl boronic acid as described in Example 1 as an off-white foam; ESMS 486 (M+1) + . 5. {5-(4-(N,N-Dimethylamino)phenyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0225] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-(N,N-dimethylamino)phenyl boronic acid as described in Example 1 as an off-white foam; ESMS 494 (M+1) + . 6. {5-(Phenyl-4-carboxamido)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]-amine [0226] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-carboxyphenylboronic acid as described in Example 3 to provide {5-(4-carboxyphenyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine. A solution of {5-(4-carboxy-phenyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, carbonyl diimidazole (1.2 eq), ammonium hydroxide (12 eq) in tetrahydrofuran (25 mL) was stirred at room temperature for 6 h. Flash chromatography (SiO 2 , 5% methanol in ethyl acetate) afforded the title compound as white solid; ESMS 494 (M+1) + . 7. {5-(4-Carboxyphenyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0227] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-carboxyphenylboronic acid as described in Example 1 to provide the title compound; ESMS 495 (M+1) + . 8. {5-(2-Thienyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0228] The title compound was prepared from (5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine, 2-thienylboronic acid as described in Example 1 to provide the title compound; ESMS 457 (M+1) + . 9. {5-(2-Furanyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0229] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 2-furanylboronic acid as described in Example 1 to provide the title compound; ESMS 441 (M+1) + . 10. {5-(3-Furanyl)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0230] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 3-furanylboronic acid as described in Example 1 to provide the title compound; ESMS 441 (M+1) + . 11. {5-(3-Thienyl)-2-[(4-pyridylmethyl)amino)pyrimidin-yl}[1-benzyl(4-piperidyl)]amine [0231] The title compound was prepared from {5-bromo-2-(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 3-thienylboronic acid as described in Example 1 to provide the title compound; ESMS 457 (M+1) + . 12. {5-(2-Furanyl)-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0232] The title compound was prepared from {5-bromo-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 2-furanylboronic acid as described in Example 1 to provide the title compound; ESMS 441 (M+1) + . 13. {5-(3-Furanyl)-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0233] The title compound was prepared from {5-bromo-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 3-furanylboronic acid as described in Example 1 to provide the title compound; ESMS 441 (M+1) + . 14. {5-(2-Thienyl)-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0234] The title compound was prepared from {5-bromo-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 2-thienylboronic acid as described in Example 1 to provide the title compound; ESMS 457 (M+1) + . 15. {5-(Phenyl-4-carboxamido)-2-[2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0235] The title compound was prepared from {5-bromo-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-carboxyphenylboronic acid as described in Example 3 to provide {5-(phenyl-4-carboxy)-2-[(2-pyridylmethyl)amino)pyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine. A solution of {5-(phenyl-4-carboxy)-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine, carbonyl diimidazole (1.2 eq), ammonium hydroxide (12 eq) in tetrahydrofuran (0.1M) was stirred at room temperature for 6 h. Flash chromatography (SiO2, 5% methanol in ethyl acetate) afforded the title compound as white solid; ESMS 494 (M+1) + . 16. N(4)-(1-Benzyl-piperidin-4-yl)-5-(3-chloro-4-fluoro-phenyl)-N(2)-pyridin-2-ylmethyl-pyrimidine-2,4-diamine [0236] The title compound was prepared from (5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 3-chloro-4-fluoro-phenyl boronic acid as described in Example 1 as an off-white foam; ESMS 503 (M+1) + . 17. N-(3-[4-(1-Benzyl-piperidin-4-ylamino)-2-[(pyridin-2-ylmethyl)-amino]-pyrimidin-5-yl]phenyl)-acetamide [0237] The title compound was prepared from (5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine, 3-acetaminophenyl boronic acid as described in Example 1 as an off-white foam; ESMS 508 (M+1) + . 18. 5-Benzo[1,3]dioxol-5-yl-N(4)-(1-benzyl-piperidin-4-yl)-N(2)-pyridin-2-ylmethyl-pyrimidine-2,4-diamine [0238] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 5-benzo[1,3]dioxolo boronic acid as described in Example 1 as an off-white foam; ESMS 495 (M+1) + . 19. 3-[4-(1-Benzyl-piperidin-4-ylamino)-2-[(pyridin-2-ylmethyl)-amino]-pyrimidin-5-yl]-phenol [0239] The title compound was prepared from (5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 3-hydroxyphenylphenyl boronic acid as described in Example 1 as an off-white foam; ESMS 467 (M+1) + . 20. 4-{4-(1-Benzyl-piperidin-4-ylamino)-2-[(pyridin-2-ylmethyl)-amino]-pyrimidin-5-yl}-phenol [0240] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-hydroxyphenyl boronic acid as described in Example 1 as an off-white foam; ESMS 467 (M+1) + . 21. 1-(4{(4-(1-Benzyl-piperidin ylamino)-2-[(pyridin-2-ylmethyl)-amino]-pyrimidin-5-yl}phenyl)-ethanone [0241] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine, 4-acetylphenyl boronic acid as described in Example 1 as an off-white foam; ESMS 493 (M+1) + . 22. 1-(3-[4-(1-Benzyl-piperidin ylamino)-2-[(pyridin-2-ylmethyl)-amino]-pyrimidin-5-yl}phenyl)-ethanone [0242] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 3-acetylphenyl boronic acid as described in Example 1 as an off-white foam; ESMS 493 (M+1) + . 23. 4-{4-(1-Benzyl piperidin-4-ylamino)-2-[(pyridin-2-ylmethyl)-amino]-pyrimidin-5-yl}N,N-di-methyl-benzamide [0243] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-dimethylaminocarbonylphenyl boronic acid as described in Example 1 as an off-white foam; ESMS 522 (M+1) + . 24. N-(4-[4-(1-Benzyl-piperidin-4-ylamino)-2-[(pyridin-2-ylmethyl)-amino]-pyrimidin-5-yl]-phenyl)-acetamide [0244] The title compound was prepared from {5-bromo-2-[(4-pyridylmethyl)amino)pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine, 4-acetaminophenyl boronic acid as described in Example 1 as an off-white foam; ESMS 508 (M+1) + . [0000] Intermediates A. (5-Bromo-2-chloropyrimidin-4-yl)[1-benzyl (4-piperidyl)]amine [0245] 4-Amino-1-benzylpiperidine (4.09 g, 0.22 mol) was added to a solution of 5-bromo-2, 4-dichloropyrimidine (4.90 g, 0.22 mol) and potassium carbonate (3.86 g, 0.28 mol) in THF (150 mL) under constant stirring at room temperature. The reaction was stirred for 30 min at room temperature then diluted with water (400 mL) and extracted with ethyl acetate (2×200 mL). The organic layer was separated and evaporated under reduced pressure to give a residue. The residue was purified using flash chromatography (SiO 2 , ethyl acetate) to give (5-bromo-2-chloropyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine (5.15 g, 65% yield) as clear oil; ESMS 381 (M+1) + . B. Ethyl 4-({5-bromo-2-chloropyrimidin-4-yl}amino)piperidinecarboxylate [0246] The title compound was prepared from ethyl 4-aminopiperdinecarboxylate and 5-bromo-2,4-dichloro-pyrimidine as described in Example A to give the title compound; ESMS 363 (M+1) + . C. {5-Bromo-2-[(2-pyridylmethyl)amino]pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0247] A solution of (5-bromo-2-chloropyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine (4.91 g, 0.13 mol) and 2-(aminomethyl)pyridine (3.20 g, 0.30 mol) was heated (neat) at 120° C. for 25 minutes. The reaction mixture was partitioned between ethyl acetate (300 mL) and saturated aqueous NaHCO 3 solution (300 mL). The organic layer was separated, washed with brine, concentrated, and purified using flash chromatography (10% methanol in ethyl acetate) to give {5-bromo-2-[(2-pyridylmethyl)amino]pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine (3.18 g 55% yield) as off-white foam; ESMS 453 (M+1) + . D. {5-Bromo-2-[(4-pyridylmethyl)amino]pyrimidin-4-yl}[1-benzyl(4-piperidyl)]amine [0248] The title compound was prepared from (5-bromo-2-chloropyrimidin-4-yl)[1-benzyl(4-piperidyl)]amine and 4-(aminomethyl)pyridine as described in Example C to provide an off-white foam; ESMS 453 (M+1) + . E. Ethyl 4-({5-bromo-2-[(2-pyridylmethyl)amino]pyrimidin-4-yl}amino)piperdinecarboxylate [0249] The title compound was prepared from Ethyl 4-({5-bromo-2-chloropyrimidin-4-yl}amino)piperidine-carboxylate and 2-(aminomethyl)pyridine as described in Example C to give the title compound; ESMS 453 (M+1) + . [0000] Biological Investigations [0250] Protein kinase C-theta is a member of the Ca 2+ -independent novel protein kinase C (PKC) subfamily, which is predominantly expressed in skeletal muscle and T-cells (Baler et al., JBC 268:4997; Bauer et al., Eur J. Immunol 30: 3645). PKC-θ was shown to selectively colocalize with the TCR to the T cell synapse when antigen-specific T cells are engaged by their physiological ligand (Monks et al., Nature 395:82; Monks et al., Nature 385:83). Functional studies of PKC-θ revealed an early and essential role in the TCR/CD28-induced stimulation of MAP kinase JNK/AP-1 and NFAT, but also the IKKβ/I-κB/NF-κB signaling cascade (see for review Altman et al., Immunol Today 21:567; Bauer and Baier, 2002 Mol. Immunol., submitted). [0251] In T cells PKC-θ activates AP-1, NFAT and NF-κB (Bauer et al., Eur. J. Immunol. 30: 3645; Lin et al., Mol Cell Biol 20:2933; Coudronniere et al., PNAS 97:3394) and PKC-θ was shown to synergize with Calcineurin in inducing the IL-2 gene (Werlen et al., EMBO J. 17:3101; Ghaffari-Tabrizi et al., Eur. J. Immunol. 29:132). Inhibition of PKC-θ leads to impaired T-cell functions (Baier-Bitterlich et al., Mol Cell Biol 16:1842; Ghaffari-Tabrizi et al., Eur. J. Immunol. 29:132). Consistently, T-cells of PKC-θ-deficient mice display profound defects in TCR-induced IL-2 production and, subsequently, T-cell proliferation (Sun et al, Nature 404:402; Pfeifhofer et al., submitted). [0252] For the investigation of PKC-θ inhibition on the enzymatic level the phosphorylation of a substrate pep-tide by recombinant PKC-θ enzyme can be measured. On the cellular level (in vitro) the immunomodulatory potential of PKC-θ inhibitors is evident from the inhibition of activated T-cell responses such as proliferation, cytokine synthesis (e.g. IL2) and expression of activation markers. Substances, which inhibit the aforementioned proinflammatory parameters are those which inhibit PKC-E. [0000] Protein Kinase C-θ Assay [0253] The compounds of formula 1 were tested for their activity on PKC-θ according to the following method. The assay was performed in 96 well microtiter plates (Perkin Elmer Wallac) at a final assay volume of 200 μl. The reaction mixture (50 μl) contained 10 μl of recombinant human PKC-θ enzyme together with 5 μl of the test compound and 3 μM biotinylated PKC-θ substrate peptide (Biotin-RKRQRSMRRRVHOH), 160 μM phosphatidylserine, 0.3 mg/ml BSA, 1 μM ATP and 2 μCi of 33 γ-ATP (Amersham) in 40 mM Tris-buffer pH 7.4. Incubation was performed for 40 min at room temperature. The reaction was stopped by adding 150 μl of a mixture containing 10 mM ATP and 1.33 mg/ml streptavidin coated yttrium silicate SPA beads (Amersham). Incorporated radioactivity (cpm) was measured for 2 min in a radioactivity counter (Wallac MicroBeta JET). According to the method described above IC 50 measurement was performed on a routine basis by incubating a serial dilution of inhibitor at the desired concentrations and a final DMSO concentration of 1% (v/v), which did not affect PKC-θ activity. IC 50 values for inhibition of PKC-θ were calculated from the concentration-inhibition curves by nonlinear-regression. [0254] The inhibitory values determined for the compounds according to the invention follow from the following table A, in which the numbers of the compounds correspond to the numbers of the examples. TABLE A Inhibition of PKC-θ activity [measured as IC 50 (μmol/l)] Example No. PKC-θ 1 <4.0 12 <4.0 13 <4.0 14 <4.0 15 <4.0 16 <4.0 17 <4.0 18 <4.0 19 <4.0 20 <4.0 21 <4.0 22 <4.0 23 <4.0 24 <4.0 [0255] To determine the effects of compounds of formula 1 on T-cell activation the following assays were performed. [0000] CD4+ Proliferation Assay [0256] CD4+ lymphocytes were purified as described by Hatzelmann and Schudt (J Pharmacol Exp Ther 297: 267-279) and resuspended in assay medium (RPMI 1640/10% fetal calf serum (FCS) containing 2 mM Glutamine, 1% sodiumpyruvate, 1% non-essential amino acids and 1% penicillin/streptomycin) at a density of 1×10 6 cells/ml. 96 well plates were coated with αCD3 antibodies (0.3 μg/well; Ortho-clone OKT-3, Jansen-Cilag) for 2.5 h at 37° C. in 5% CO 2 and then washed twice with PBS (200 μl/well). Prior to plating of the cells (200 μl, 2×10 5 cells) the compounds of formula 1 dissolved in 2% DMSO were added to the antibody-coated plates at the desired concentrations. Following a preincubation period of 30 min at 37° C. and 5% CO 2 10 μl of αCD28 antibody (3 μg/ml, Beckman) were added and incubation continued for 48 h at 37° C. and 5% CO 2 . 18 h prior to cell harvest 10 μl of 3 H-methylthymidin ( 0 . 2 μCi, Amersham) were added. After 48 h total incubation time the cells were lysed using deionized water and radiolabeled DNA was immobilized on 96 well filter plates using a Tomtec device. The plates were dried at 60° C. for 1 h and overlayed with 40 μl Microscint-O (Packard) before counting in a Topcount radioactivity counter (Packard). Calculation of IC50 values was performed as described above. [0257] The inhibitory values determined for the compounds according to the invention follow from the following table B, in which the numbers of the compounds correspond to the numbers of the examples. TABLE B Inhibition of CD4+ cell proliferation [measured as IC 50 (μmol/l)] CD4+ Example No. proliferation 1 <4.0 8 <4.0 14 <4.0 15 <4.0 CD4+ IL-2 Secretion Assay [0258] CD4+ T lymphocytes were stimulated and treated with compounds of formula 1 as described above for the CD4+ proliferation assay. Following a 48 h incubation period IL-2 levels in the supernatants (50 μl/well) were determined by ELISA (Beckman Coulter). Calculation of IC 50 values was performed as described above. [0259] The inhibitory values on CD4+ T-cell activation determined for the compounds according to the invention follow from the following table C, in which the numbers of the compounds correspond to the numbers of the examples. TABLE C Inhibition of IL-2 secretion in CD4+ cell [measured as IC 50 (μmol/l)] CD4+ IL2 Example No. proliferation 1 <4.0 6 <4.0 8 <4.0 12 <4.0 13 <4.0 14 <4.0 15 <4.0 The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications are intended to be included within the scope of the following claims.

The invention relates to substituted diaminopyrimidine compounds, which are effective therapeutic compounds for treating diseases and disorders associated with those commonly treated by Protein Kinase C theta (PKCθ) inhibitors.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to wireless signal transmission systems and, more specifically, to an Improved Signal Receiver Having Wide Band Amplification Capability. 2. Description of Related Art In a conventional infrared transceiver system 10 depicted by the diagram of FIG. 1 , infrared signals 14 are received by an infrared diode 12 . These incident infrared signals 14 generate a current within the infrared diode 12 , which is conventionally converted to a voltage signal by shunting the system with resistor R S , as shown. This relatively low-voltage signal is then passed through a voltage amplifier 16 . The signal then passes through various stages of staged amplification 18 before being carried on out of the system as the output signal V IRRX . What should be appreciated is at node V OUT the signal is essentially the incident IR signal 14 , plus any noise created by the IR diode 12 or the resistor R S . It should be apparent that the better the signal-to-noise ratio at V OUT , the better and cleaner the amplification through the voltage amplifier 16 and the subsequent staged amplification 18 . Now turning to FIG. 2 , we can discuss the operation of the conventional system in more depth. FIG. 2 is a schematic of a single-ended version of a conventional infrared transceiver system of FIG. 1 . As can be seen in FIG. 2 , the IR diode 12 is simulated by current source I 1 and capacitance C 1 . R S of FIG. 1 is here R 7 , shunted with the current source. Essentially, what we have in this diagram is a current mirror 20 and a voltage amplifier 22 . What should be appreciated from this circuit is that in normal operation the typical input level for fast infrared (FIR) frequency bandwidth will result in approximately 0.5 micro amps of current at current source I 1 , which results in 106 micro volts across a “real” 212 ohm resistor R 7 . Under such conditions, the resistor R 7 will have a thermal noise of 17.8 micro volts (at 40 MHz frequency bandwidth), which results in a noise ratio of 15.5 decibels without even having entered the amplification stages. If we now look at the operation of the amplifier 22 , we can see that typically, it is a high impedance voltage amplifier. The problem with this type of voltage amplifier is that R 7 , which is required for the specified system bandwidth, also provides additional noise that is added to the incident infrared signal 14 (at V OUT ) before the signal is amplified—this further decreases the signal-to-noise ratio. It should also be understood that since the “Miller Effect” will apply to the input stage, the value of the intrinsic gate-to-drain capacitance of such a stage is multiplied by the voltage gain. For example, a voltage gain of 10 will result in a “Miller Effect” drain-to-gate capacity of 11 times. In order to achieve the desired bandwidth, a Cascode stage becomes a necessity. The addition of this Cascode stage results in a corresponding addition of another transistor-based noise contribution discussed above (i.e. a total of two equal noise-contributing stages). Consequently, this phenomena further degrades the signal to noise ratio and harms the amplifier performance. Another type of amplifier has been conventionally used, in which R 7 is replaced by a feedback resistor. This amplifier has not been discussed herein, since its design is limited to a lower bandwidth, in particular, because of its poor noise performance. Now turning to FIG. 3 , we can see a preferred model for the prior art circuit of FIG. 2 . FIG. 3 is a simulation of the circuit of FIG. 2 provided for the purposes of modeling the performance of the circuit; the pertinent results of this modeling are shown in FIGS. 4 and 5 . FIG. 4 is a plot of noise vs. frequency bandwidth for the conventional circuit of FIGS. 1 through 3 . As can be seen, at a frequency of approximately 40 MHz (which is in the FIR bandwidth), the spot noise is 1.6×10 −21 /√{square root over (Hz)} approximately. This number will become more significant once we discuss the improvements of the present invention. Now turning to FIG. 5 we can see the effect of these noises and capacitance's created in the prior art voltage feedback type amplification circuit. FIG. 5 a response plot of output voltage (V IRRX ) for the prior system of FIG. 2 . As can be seen, the peaks and valleys are extremely erratic and choppy, which creates an unstable signal and ultimately inferior data processing. What is needed is an improved amplifier system to reliably handle in excess of 40 MHz frequency bandwidth. SUMMARY OF THE INVENTION In light of the aforementioned problems associated with the prior systems and devices, it is an object of the present invention to provide an Improved Signal Receiver Having Wide Band Amplification Capability. The preferred receiver should be able to receive and reliably amplify infrared and/or other wireless signals having frequency bandwidths in excess of 40 MHz. It is an object of the present invention to reduce the signal-to-noise ratio of the received signal to ⅕ th of the prior systems. In its preferred form, the receiver will eliminate both shunting and feedback resistors on the input end by amplifying the signal in current form. Furthermore, the receiver will include transconductance amplification means for amplifying the current signal without the need for Cascode stages. It is a further object that the receiver include staged amplification to amplify the current signal in stages prior to converting the signal into a voltage output. BRIEF DESCRIPTION OF THE DRAWINGS The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, of which: FIG. 1 is a functional diagram of a conventional eared transceiver system; FIG. 2 is a schematic of the conventional infrared transceiver system of FIG. 1 ; FIG. 3 is a simulation of the circuit of FIG. 2 provided for the purposes of modeling the performance of the circuit; FIG. 4 is a plot of frequency bandwidth of noise to frequency bandwidth for the conventional circuit of FIGS. 1 through 3 ; FIG. 5 a plot of output voltage keeping the effect of the high system noise characteristics; FIG. 6 is a functional diagram of an improved infrared transceiver system of the present invention using current amplification; FIG. 7 is a preferred circuit design of the circuit of FIG. 6 ; FIG. 8 is a circuit model of the circuit of FIGS. 6 and 7 ; FIG. 9 is a plot of noise versus bandwidth of the circuit of FIGS. 6 , 7 , and 8 ; and FIG. 10 is a plot of output voltage of the circuit of FIGS. 6 , 7 , 8 , and 9 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventors of carrying out their invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide an Improved Signal Receiver Having Wide Band Amplification Capability. The present invention can best be understood by initial consideration of FIG. 6 . FIG. 6 is a functional diagram of an improved infrared transceiver system 24 of the present invention, employing current amplification. In this system 24 , the IR signals 14 incident upon the IR diodes remain in the form of a current (I OUT ). The Current (I OUT −I F ) develops voltage across R INEFF (Effective Input Resistance=R IN /(1+βA OL ). This voltage is multiplied by the Transconductance of the current amplifier 26 , producing a current through R L , giving a voltage input to the buffer 32 . This pre-amplifier output voltage is converted to a feedback current (I F ) by device X 3 . I F is then combined with I OUT which results in a reduction in the size of R IN (noiselessly), which ultimately improves the bandwidth of the system. Now turning to FIG. 7 , we can see the preferred circuit design for the improved transceiver system 24 of FIG. 6 . As can be seen, in this case, current generator 13 and capacitor C 4 simulate the IR diode 12 . In contrast to the prior voltage-type amplifier depicted in FIGS. 2 and 3 , the amplifier 30 of this FIG. 7 is a transimpedence-type amplifier. With the transimpedence amplifier, since there is typically no resistive feedback loop (i.e. there is no feedback resistor), the intrinsic system noise is substantially reduced. Furthermore, the significant benefit of using this topology for the transimpedence amplifier is that it does not result in a Miller effect, and therefore there is only a noise contribution from a single input stage (since the full Cascode stage is rendered unnecessary by the absence of a Miller effect). The result is an amplifier that is capable of extremely high signal-to-noise ratios, in addition to very good bandwidth, since R INEFF is equal to R IN /(1+βA OL ). In order to potentially achieve further performance improvements, the transistors X 3 , X 6 , X 7 and/or X 4 might include dynamically-adjustable bias voltage control in order to operate these transistors in the “weak inversion” range for certain portions of their operational curves. Since weak inversion operations are well known in the art, the particulars of this operational mode are not discussed herein. For the purposes of this discussion, a 0.7μ CMOS process is employed; it should be understood that additional system capacitance reductions (and therefore performance improvements) might be achievable through the use of smaller geometry. FIG. 8 is a circuit model of the circuit of FIGS. 6 and 7 constructed in order to provide simulation data on the circuit, as reported below in FIGS. 9 and 10 . FIG. 9 is a plot of noise versus frequency bandwidth of the circuit of FIGS. 6 , 7 , and 8 . If we look at the 40 MHz line we can see that the spot noise at 0.54×10 −21 /√{square root over (Hz)} this point is This compares to 1.6×10 −21 of the prior circuit, or approximately ⅓ the spot noise at equivalent frequency in the new circuit of FIG. 7 (as compared to the old circuit of Figure 2 ), which equates to a 13 dB improvement when integrated over the full frequency range. Also, at 3 dB signal-to-noise ratio, the frequency bandwidth exceeds 64 MHz. As can be seen from FIG. 10 , the improvement in responsiveness of the transimpedence solution is dramatic. FIG. 10 is a plot of output voltage of the circuit of FIGS. 6 , 7 , 8 , and 9 . In contrast to the sawtooth response curve of FIG. 5 , FIG. 10 shows a smooth output through several signal pulses. It should be understood from FIGS. 9 and 10 that the device of the present invention will provide extremely high bandwidths with low noise while at the same time giving very, very smooth response. It also should also be understood that while throughout this application the embodiments discussed have been in regard to infrared signal receipt, this method can also be expected to provide the same benefits for other wireless signal receipt, for example radio frequency, and in particular cellular phones and other devices. Through application of this technology it is believed that the noise improvement of 15 to 16 decibels will result in an incredible increase in-range and coverage that heretofore has not been achievable. Theoretical Noise Comparison to the Prior Art The following analysis is provided in order to further explain the significant benefits of the signal receiver of the present invention. A noise comparison between the prior art amplifier and the amplifier of the present invention revolves around the input transistor and the input resistor, since the system signal-to-noise ratio is essentially determined at this point in the respective circuits. In the prior art circuit (see FIG. 2 ), R 7 is the input resistor, X 5 is the input transistor—as discussed above, X 5 is a Cascode connection. In the preferred circuit of the present invention, there is NO input resistor, as well as NO Cascode connection. Input Resistor Contribution In the prior circuit, assume that a Bandwidth of 40 MHz drives R 7 to be 265 Ω (in order to have adequate gain without decreasing the signal-to-noise ratio to an unacceptable level). The formula for RMS noise generated in a resistor is: i RMS ⁡ ( resistor ) = 4 ⁢ xkxT R , where: k=Boltzman's constant=1.38×10 −23 T=Temperature (deg. Kelvin)=290 R=Resistor value=265 , such that: i RMS ⁡ ( R7 ) = 4 ⁢ x1 ⁢ .38 × 10 - 23 ⁢ x290 265 = 49.16 ⁢   ⁢ nanoAmperes Input Transistor Contribution The thermal noise of one input MOSFET is calculated by the following formula: i RMS ⁡ ( MOSFET ) = { 8 ⁢ xkxT 3 } ⁢ x ⁢ 2 ⁢ x ⁢   ⁢ β ⁢   ⁢ xId , where: β=K′×W/L K′ is a transconductance parameter=30.3×10 −6 W/L are width and length dimensions of the MOSFET=55/1 (therefore β=7.575×10 −4 ) Id is the MOSFET drain current=60×10 −6 (for this case) , such that: i RMS ⁡ ( MOSFET ) = { 8 ⁢ x1 ⁢ .38 ⁢ x10 - 23 ⁢ x290 3 } ⁢ x ⁢ 2 ⁢ x7 ⁢ .575 ⁢ x10 - 4 ⁢ x60x10 - 6  i RMS (MOSFET)=11.34 nanoAmperes Comparison between the Circuits: Assume that the input current source may drop as low as 250 nanoAmperes (fairly common for infrared communications). The prior circuit's input components' noise: i RMS (input)=i RMS (R7)+i RMS (MOSFET) , but since X 5 is Cascode-connected, there are essentially two noise contributions, making the combined contribution equal to the square root of their squared contributions, therefore: i RMS ⁡ ( input ) = i RMS ⁡ ( R7 ) 2 + 2 ⁢ x ⁢ { i RMS ⁡ ( MOSFET ) } 2 i RMS ⁡ ( input ) = 49.16 2 + 2 ⁢ x ⁢ { 11.3 } 2 = 51.6 ⁢   ⁢ nanoAmperes . The preferred circuit of the present invention's input components' noise Since there is no input resistor, the formula for the comparable noise current is simply: i RMS (input)=i RMS (MOSFET) i RMS (input)=11.34 nanoAmperes Signal-to-Noise Ratio Comparison: S:N(prior circuit)=250:51.6=4.85:1 S:N(present invention)=250:11.34=22.0:1! This represents over 5 (five) times the signal-to-noise ratio of the prior circuit, which, when coupled with the superior frequency performance described previously, clearly demonstrates the previously-unknown benefits of the present circuit and method over the prior devices and methods. 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.

An Improved Signal Receiver Having Wide Band Amplification Capability is disclosed. Also disclosed is a receiver that is able to receive and reliably amplify infrared and/or other wireless signals having frequency bandwidths in excess of 40 MHz. The receiver of the present invention reduces the signal-to-noise ratio of the received signal to ⅕th of the prior systems. The preferred receiver eliminates both the shunting resistor and the feedback resistor on the input end by amplifying the signal in current form. Furthermore, the receiver includes transconductance amplification means for amplifying the current signal without the need for Cascode stages. Finally, the receiver includes staged amplification to amplify the current signal in stages prior to converting the signal into a voltage output.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an exposure apparatus and a method for manufacturing 3-D horn antenna using the exposure apparatus. More particularly, it relates to a method for manufacturing a horn-shaped 3-D micro-structure antenna and an extremely low-speed, inclined-rotating, parallel exposure apparatus that makes it possible to manufacture the 3-D micro-structure antenna mentioned above. [0003] 2. Description of the Related Art [0004] A chuck of an exposure apparatus, which is a photo-processing apparatus for manufacturing a Micro-Electro-Mechanical System(MEMS), generally has a horizontal structure. However, it is difficult to construct a horn-shaped 3-D micro-structure antenna by using a chuck of an exposure apparatus having a horizontal structure. [0005] And, it appears, by calculation, that the structure of an exposure apparatus to obtain parallel light to be exposed has a comparably high vertical structural shape. [0006] [0006]FIG. 1 is a view illustrating the overall structure of a prior exposure system having horizontal structure by using mirror reflection. And FIG. 2 is a view showing an exposure simulation result of a horizontal-structure exposure apparatus. [0007] Referring to FIG. 1, the system comprises numbers of reflecting mirrors, a fly eye lens(F.E.L), a plate lens, and a collimating lens. [0008] However, in case of manufacturing a 3-D inclined structure using an ultraviolet lithographic process, which is a general MEMS process, the function of an antenna is insufficient because the homogeneity of the surface is considerably lowered as described in FIG. 2. [0009] And, there exists a problem of securing a sufficient room for installing an exposure apparatus having a special structure to obtain parallel light in a general experimental room. SUMMARY OF THE INVENTION [0010] The present invention is proposed to solve the problems of the prior art mentioned above. It is therefore the object of the present invention to provide a novel method for manufacturing a horn-shaped 3-D micro-structure antenna. [0011] It is another object of the present invention to provide a method of constructing an extremely low-speed, inclined-rotating, parallel exposure apparatus that makes it possible to manufacture the 3-D micro-structure antenna mentioned above. [0012] It is yet another object of the present invention to provide a method of constructing an exposure apparatus having horizontal structure, instead of vertical structure, by using reflection of mirrors installed inside the mirror box of the exposure apparatus. [0013] To achieve the object mentioned above, the present invention presents: (1) an exposure apparatus by which light is exposed by rotating a chuck, on which a mask and a wafer are united, with extremely low-speed in an inclined state, (2) a method of reducing the size of an exposure apparatus by constructing a horizontal-structure mirror box using reflection of mirrors installed inside, to overcome the comparably-high theoretical vertical length of the mirror box to obtain parallel light in the prior exposure apparatus, and (3) a method of manufacturing 3-D micro system using the exposure apparatus. BRIEF DESCRIPTION OF THE DRAWINGS [0014] [0014]FIG. 1 is a view illustrating the overall structure of a prior exposure system having horizontal structure by using mirror reflection. [0015] [0015]FIG. 2 is a view showing an exposure simulation result of a horizontal-structure exposure apparatus. [0016] [0016]FIG. 3 is a view illustrating the overall structure of a mirror-reflection type, horizontal-structure, parallel exposure apparatus, in which an extremely low-speed, inclined-rotating, exposure chuck is installed, in accordance with the present invention. [0017] [0017]FIG. 4 is a view illustrating the details of a calibration-capable reflection mirror in the exposure apparatus described in FIG. 3. [0018] [0018]FIG. 5 is a view illustrating the structure of an extremely low-speed, inclined-rotating, exposure chuck in the exposure apparatus described in FIG. 3. [0019] [0019]FIG. 6 a ˜FIG. 8 f are views illustrating the manufacturing procedures of a horn-shaped 3-D micro-structure antenna in accordance with the present invention. DESCRIPTION OF THE NUMERALS ON THE MAIN PARTS OF THE DRAWINGS [0020] [0020] 10 : a power supply [0021] [0021] 20 : a lamp cooler [0022] [0022] 30 : a mirror box of exposure apparatus [0023] [0023] 40 : a chuck [0024] [0024] 50 : a motor [0025] [0025] 60 : a vacuum device [0026] [0026] 70 : a computer [0027] [0027] 100 : a semiconductor substrate [0028] [0028] 102 : a sacrificial oxide film [0029] [0029] 104 : the first photosensitive film [0030] [0030] 106 : an exposure mask [0031] [0031] 108 the first metal film [0032] [0032] 110 : a micro-structural body [0033] [0033] 112 : a polymer thick film [0034] [0034] 114 : the second photosensitive film [0035] [0035] 116 : a round [0036] [0036] 118 : the second metal film [0037] [0037] 120 : the third metal film [0038] [0038] 122 : the third photosensitive film [0039] [0039] 124 : the fourth metal film DETAILED DESCRIPTION OF THE EMBODIMENTS [0040] Hereinafter, referring to appended drawings, the structure and the operation procedures of the embodiments of the present invention are described in detail. [0041] [0041]FIG. 3 is a view illustrating the overall structure of a mirror-reflection type, horizontal-structure, parallel exposure apparatus, in which an extremely low-speed, inclined-rotating, exposure chuck is installed, in accordance with the present invention. FIG. 4 is a view illustrating the details of a calibration-capable reflection mirror in the exposure apparatus described in FIG. 3, and FIG. 5 is a view illustrating the structure of an extremely low-speed, inclined-rotating, exposure chuck in the exposure apparatus described in FIG. 3. [0042] Referring to FIG. 3, the system comprises: a power supply( 10 ) to provide an electric power for actuating the exposure apparatus; a lamp cooler( 20 ) to reflect the parallel light generated from a parallel light lamp; a mirror box( 30 ) of the exposure apparatus having a certain horizontal/vertical length to obtain the parallel light output reflected by the lamp cooler( 20 ) via numbers of reflecting mirrors; a chuck( 40 ) that carries out an exposure process, by an extremely low-speed rotation in an inclined state, using the parallel light output through the mirror box( 30 ) of the exposure apparatus; a motor( 50 ) to actuate the chuck( 40 ) to rotate in an extremely low-speed; a vacuum device( 60 ) to maintain the vacuum state of the chuck( 40 ); and a computer( 70 ) to control the inclination, the rotational speed, and the rotation time of the chuck( 40 ). [0043] Referring to FIG. 4, the lamp cooler( 20 ) comprises a reflecting shade( 22 ) to reflect the parallel light and a parallel light lamp( 24 ). [0044] Inside the mirror box( 30 ) of the parallel exposure apparatus connected to the lamp cooler( 20 ), numbers of reflecting mirrors( 32 a , 32 b , 32 c , 32 d , 32 e , and 32 f ), a fly eye lens( 34 ), a plate lens( 36 ) and a collimating lens( 38 ) are installed respectively. And, a shutter( 39 ), which controls the exposure level of parallel light, is installed at the end of the mirror box( 30 ). [0045] In addition, mirror angle calibrators( 32 g ), which calibrate the mirror angle, are installed at the reflecting mirrors( 32 a , 32 b , 32 c , 32 d , 32 e , and 32 f ). [0046] Here, an excimer laser as well as an ultraviolet light can be used as a light source in the exposure apparatus, and the power of the light source can be controlled. [0047] Referring to FIG. 5, the main body( 40 a ) of the chuck( 40 ) is equipped with fixing devices( 42 a , 42 b ) that unite a mask and a wafer at the body. [0048] Thus, the chuck( 40 ) carries out exposure process in an inclined state having a mask united on top of the wafer fixed at the main body( 42 a ). [0049] Here, the symbol T indicates the inclination range of the chuck( 40 ) on which the mask and the wafer are united, and the symbol S indicates the rotation range of the chuck( 40 ) on which the mask and the wafer are united. [0050] Looking into the operation procedures of a parallel exposure apparatus having a mirror-reflection type horizontal structure as described before, when an electric actuating power is provided to the parallel exposure apparatus from a power supply( 10 ), a lamp cooler( 20 ) generates parallel light, and thereafter the parallel light outputs through numbers of reflecting mirrors( 32 a , 32 b , 32 c , 32 d , 32 e , and 32 f ) installed inside the mirror box( 30 ) of the exposure apparatus. [0051] Next, the chuck( 40 ) of the exposure apparatus carries out exposure process, in the form of a mask united on top of the wafer, by the extremely low-speed rotational actuation by the low-speed motor( 50 ) within the inclination/rotation range of the chuck. [0052] [0052]FIG. 6 a ˜FIG. 8 f are views illustrating the manufacturing procedures of a horn-shaped 3-D micro-structure antenna in accordance with the present invention. [0053] Referring to FIG. 6 a and FIG. 6 b , a sacrificial oxide film( 102 ) is deposited on top of a semiconductor substrate( 100 ). And then, the first photosensitive film( 104 ) is coated on the sacrificial oxide film( 102 ), and exposing/developing processes are carried out using an exposure mask( 106 ) thereafter. [0054] Here, a mask, at which a pattern is formed to lithograph the light only to the center portion, is used for the exposure mask( 106 ). [0055] Referring to FIG. 6 c and FIG. 6 d , after a pattern being formed on the first photosensitive film( 104 ) by the exposing/developing processes, the first metal film( 108 ) is deposited thereon, with a thickness enough for covering the pattern of the first photosensitive film( 104 ), by using an electroless plating technique. [0056] Here, the pattern of the first photosensitive film( 104 ) has a horn-shaped structure. [0057] Referring to FIG. 6 e and FIG. 6 f , after being deposited, the first metal film( 108 ) is polished by chemical/mechanical polishing(CMP) process until the upper surface of the pattern of the first photosensitive film( 104 ) comes out. And thereafter, the horn-shaped pattern of the first photosensitive film( 104 ) is eliminated by plasma asher process. [0058] Next, the first metal film( 108 ) is polished by CMP process to have a designated thickness to constitute a horn-shaped micro-structure. [0059] And, referring to FIG. 7 a and FIG. 7 b , after a horn-shaped micro-structure( 110 ) is constituted by the sacrificial oxide film( 102 ) being separated and eliminated, a polymer thick film( 112 ) is deposited thereon. [0060] Here, the polymer thick film( 112 ) is deposited up to a thickness enough to cover the whole space where the eliminated first photosensitive film( 104 ) pattern existed. [0061] Next, referring to FIG. 7 c and FIG. 7 d , the second photosensitive film( 114 ) is coated thereon, and thereafter a pattern of the second photosensitive film( 114 ) is formed by patterning process using a mask(not described in the figure) at which a pattern is formed to lithograph the light only to the center portion. [0062] And then, referring to FIG. 7 e and FIG. 7 f , a round( 116 ) is formed at the surface of the polymer thick film( 112 ), exposed by the pattern of the second photosensitive film( 114 ), by performing dry etching process on the whole surface. Thereafter, the second photosensitive film( 114 ) pattern is eliminated. [0063] Next, referring to FIG. 7 g , the second metal film( 118 ) is deposited thereon, and thereafter a polishing process is performed, using CMP process, until the round( 116 ) of the second metal film( 118 ) is eliminated. [0064] Next, referring to FIG. 8 a and FIG. 8 b , the third metal film( 120 ) is deposited thereon, and the third photosensitive film( 122 ) is coated on the third metal film( 120 ). And then, a pattern of the third photosensitive film( 122 ) is formed by patterning process by which the pattern is formed only at the portion designated to be a waveguide of 3-D antenna. [0065] Next, referring to FIG. 8 c , and FIG. 8 d , a pattern of the third metal film( 120 ) is formed to be superposed on the pattern of the third photosensitive film( 122 ) by patterning process in which the pattern of the third photosensitive film( 122 ) is used as an etching barrier. [0066] Next, referring to FIG. 8 e , and FIG. 8 f , the pattern of the third photosensitive film( 122 ) is eliminated, and thereafter a pattern of polymer thick film( 112 ) is formed by an oxidative anisotropic etching process in which the pattern of the third metal film( 118 ) is used as an etching barrier. [0067] Next, the fourth metal film( 124 ) is deposited thereon using an electroless plating technique. Thereafter, a 3-D micro-structure antenna is finally produced by eliminating the pattern of the third metal film( 120 ) and the pattern of the polymer thick film( 112 ) from the semiconductor substrate( 100 ) by plasma asher process. [0068] As mentioned thereinbefore, an extremely low-speed, inclined-rotating, parallel exposure apparatus and method for manufacturing 3-D micro-structure antenna using the exposure apparatus in accordance with the present invention have the following advantages: [0069] First, the present invention can be applied to manufacturing a horn-shaped 3-D micro-structure antenna array, which can not be manufactured easily by prior MEMS process. [0070] Second, the present invention provides a method of reducing the size of an exposure apparatus by constructing a horizontal-structure mirror box using reflection of mirrors installed inside, to overcome the comparably-high vertical length of the mirror box to obtain parallel light in the prior exposure apparatus. Thus, experiment can be easily performed in a general experimental room. [0071] Third, the exposure apparatus in accordance with the present invention can be applied to manufacturing various types of 3-D micro-structures because it can control the inclination, the rotational speed, and the rotation time of the chuck on which a mask and a wafer are united. [0072] Since those having ordinary knowledge and skill in the art of the present invention will recognize additional modifications and applications within the scope thereof, the present invention is not limited to the embodiments and drawings described above.

The present invention relates to an exposure apparatus and a method for manufacturing 3-D horn antenna using the exposure apparatus. More particularly, it relates to a method for manufacturing a horn-shaped 3-D micro-structure antenna and an extremely low-speed, inclined-rotating, parallel exposure apparatus that makes it possible to manufacture the 3-D micro-structure antenna mentioned above.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates generally to the power flow analysis of a power grid embedded with a generalized power flow controller in the technical field, and more particularly to a method to incorporate the steady-state model of a generalized power flow controller into a conventional Newton-Raphson power flow algorithm, which can be applied to calculate the power flow solution of a power grid embedded with the generalized power flow controller. [0003] 2. Description of Related Art [0004] In the last decade, the power industry has extensively employed an innovative Flexible Alternative Current Transmission System (FACTS) technology to improve the utilization of existing transmission facilities. Connecting several Voltage Sourced Converters (VSCs) together forms various multiple functional FACTS controllers, such as: Static Synchronous Compensator (STATCOM), Unified Power Flow Controller (UPFC), and Generalized Unified Power Flow Controller. [0005] The STATCOM, as shown in FIG. 1 , has one shunt VSC. The AC side of the shunt VSC connects to a bus of a power grid through a coupling transformer, and the DC side connects to a capacitor. The STATCOM provides reactive power compensation to regulate the voltage magnitude of the connected bus at a fix level. [0006] The UPFC, as shown in FIG. 2 , has one shunt VSC and one series VSC. The AC side of the shunt VSC connects to a bus through a shunt coupling transformer, whereas the AC side of the series VSC is in series with a transmission line through a series coupling transformer. The DC sides of the shunt and series VSCs sharing the same capacitor. The shunt VSC can regulate the voltage magnitude of the connected bus at a fixed level, and the series VSC can control the active and reactive power of the connected transmission line. [0000] The GUPFC, as shown in FIG. 3 , comprises one shunt VSC and a plurality of series VSCs. The connections and functions of the VSCs of GUPFC like those in the UPFC. These VSCs enable the GUPFC to control the voltage magnitude of the bus connected with the shunt VSC, and to control the active and reactive power of each transmission line which is in series with the series VSC. [0007] The disclosed generalized power flow controller has a more flexible structure than the GUPFC. Comparing FIG. 3 and FIG. 4 , both the GUPFC and the generalized power flow controller has one shunt branch and a plurality of series branches. In GUPFC, the shunt branch and the receiving-end of each series branch connect to a common bus, bus s 1 , however, in the disclosed generalized power flow controller, the shunt branch and the receiving-end of each series branch are allowed to connect to different buses, bus s 1 , bus s 2 ˜s n , respectively. [0008] The versatility of the generalized power flow controller can be applied to equalize both the active and reactive power in the transmission lines, relieve the overloaded transmission lines from the burden of reactive power flow, and restore for declines in resistive as well as reactive voltage drops. [0009] Developing a steady-state model of the generalized power flow controller is fundamentally important for a power flow analysis of a power grid embedded with the generalized power flow controller. The power flow analysis provides the information of impacts on a power system after installing the generalized power flow controller. Many steady-state models of STATCOM, UPFC and GUPFC applied to power flow analysis have been set forth. In 2000, a STATCOM steady-state model accounting for the high-frequency effects and power electronic losses is proposed in an article “An improved StatCom model for power flow analysis”, by Zhiping Yang; Chen Shen; Crow, M. L.; Lingli Zhang; in IEEE Power Engineering Society Summer Meeting, 2000, Volume 2, Page(s):1121-1126. [0010] A conventional approach to calculate the power flow solution of a power grid that includes a unified power flow controller is disclosed in an article “Unified power flow controller: a critical comparison of Newton-Raphson UPFC algorithms in power flow studies” by C. R. Fuerte-Esquivel and E. Acha in IEE Proc. Generation, Transmission & Distribution, 1997, and in an article “A comprehensive Newton-Raphson UPFC model for the quadratic power flow solution of practical power network” by C. R. Fuerte-Esquivel, E. Acha and H. Ambriz-Perez in IEEE Trans. Power System, 2000. In 2003, X.-P. Zhang developed a method to incorporate a voltage sourced based model of GUPFC into a Newton-Raphson power flow algorithm in an article “Modeling of the interline power flow controller and the generalized unified power flow controller in Newton power flow”, IEE Proceedings. Generation, Transmission & Distribution, Vol. 150, No. 3, May. 2003, pp. 268-274. The method included the voltage magnitude and phase angle of the equivalent voltage source into the state vector of Newton-Raphson iteration formula. The number of appended state variables is twice the number of VSCs. Thus, the length of state vector is varied depending on the number of VSCs. Therefore, the prior art can only be applied to the case with fixed number of VSCs. It can not be extended to the applications of STATCOM and UPFC. Besides, the speed of convergence is sensitive to the initial values of control variables of GUPFC. The initial values of control variables need a careful selection. Improper selection of the control variables may cause the solutions oscillating or even divergent. [0011] Although the steady-state models of STATCOM, UPFC and GUPFC have been widely discussed individually, a method to incorporate steady-state models of STATCOM, UPFC, GUPFC and the generalized power flow controller into a Newton-Raphson power flow algorithm in a single framework have not been disclosed. SUMMARY OF THE INVENTION [0012] It is, therefore, an object of the present invention to provide a method to incorporate the steady-state model of a generalized power flow controller into a Newton-Raphson power flow algorithm with a robustness and rapid convergence characteristic, wherein the convergence speed is not sensitive to the selection of initial values of control variables of the generalized power flow controller. [0013] It is another object of the present invention to provide a method to incorporate the steady-state model of the generalized power flow controller into a Newton-Raphson power flow algorithm, wherein the steady-state model has a flexible structure which can be applied to calculate the power flow solution of a power grid embedded with STATCOM, UPFC, GUPFC and the generalized power flow controller in a single framework. [0014] To carry out previously mentioned objects, an innovative steady-state model of the generalized power flow controller is disclosed. The steady-state model has a flexible structure, wherein the sending-end of the each series VSC doesn't confine to connect to the same bus as the shunt converter connected. The feature of the steady-state model is expressing the variables of the steady-state model in a rectangular coordinate. Transforming the phasor from a conventional polar coordinate into d-q components reduces the appended state variables in the Newton-Raphson iteration. As a result, the increased iterations introducing by the generalized power flow controller is fewer than the prior art. The power flow calculation can preserve a rapid convergence characteristic. [0015] In addition, a method to incorporate the steady-state model of the generalized power flow controller is disclosed. The method only incorporates the control variables of the shunt VSC into the state vector of Newton-Raphson power flow algorithm. The equivalent voltages of the series VSCs are calculated directly from the power flow control objectives and the bus voltages. Thus, the length of the state vector is the same regardless the number of series VSCs. As a result, the present invention can be utilized to calculate the power flow solution of a power grid embedded with STATCOM, UPFC, GUPFC and the generalized power flow controller. [0016] The above and other objects and efficacy of the present invention will become more apparent after the description takes from the preferred embodiments with reference to the accompanying drawings is read. BRIEF DESCRIPTION OF THE DRAWINGS [0017] FIG. 1 is the interconnection of a STATCOM and a power grid according to the present invention; [0018] FIG. 2 is the interconnection of a UPFC and a power grid according to the present invention; [0019] FIG. 3 is the interconnection of a GUPFC and a power grid according to the present invention; [0020] FIG. 4 is the interconnection of a generalized power flow controller and a power grid according to the present invention; [0021] FIG. 5 is an equivalent circuit of a generalized power flow controller according to the present invention; [0022] FIG. 6 is a flow chart for finding the power flow solution of a power grid embedded with the generalized power flow controller according to the present invention; [0023] FIG. 7 shows the progress of control variables of the generalized power flow controller at each iteration according to the present invention. [0024] FIG. 8 shows power mismatches of buses of the generalized power flow controller at each iteration according to the present invention; and [0025] FIG. 9 shows a quadratic convergence pattern of the solution process according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0026] The generalized power flow controller 100 is a multi-functional FACTS controller. As depicted in FIG. 4 , the generalized power flow controller comprises a plurality of voltage sourced converters (VSCs) 111 , 121 , 131 and a plurality of coupling transformers 112 , 122 , 132 . These VSCs are connected back-to-back to share a common DC bus. The AC sides of VSCs couple to a power grid through coupling transformers, and the DC sides of VSCs link together to a DC coupling capacitor 110 . [0027] One of these VSCs, VSC 1 111 , connects to an AC bus 113 in parallel, and the other VSCs 121 , 131 coupled to transmission lines 125 , 135 in series. These VSCs exchange active power via the common DC bus. The shunt VSC, VSC 1 111 , can provide the reactive power compensation to regulate the voltage magnitude at its connected bus s 1 113 , whereas each of the series VSCs, VSC 2 -VSC n 121 , 131 , can provide both the active and reactive power compensation to concurrently control the active and reactive power of the connected transmission line 125 , 135 . [0028] The main function of VSC 1 is to keep a fixed DC voltage at DC bus by balancing the active power transfer among VSCs. The remaining capacity of VSC 1 is utilized to regulate the voltage magnitude at bus s 1 . In other words, the active power generated/absorbed by VSC 1 is restricted by the operation of other VSCs. Thus, the VSC 1 111 has only one control degree of freedom. It can provide the reactive power compensation to regulate the voltage magnitude of bus s 1 . On the other hand, each of series VSCs, VSC 2 -VSC n 121 , 131 , has two control degrees of freedom. It can simultaneously provide the active and reactive power compensation to control the active and reactive power in transmission line. [0029] The equivalent circuit of the generalized power flow controller according to the present invention is derived next. As shown in FIG. 5 . The equivalent circuit includes one shunt branch and a plurality of series branches. Each branch comprises an equivalent voltage source in series with an impedance, wherein the equivalent voltage source models the VSC, and the impedance models the coupling transformer. The operation of these equivalent voltage source is dependent on each other. An active power balance equation, which will be derived later, must be satisfied to conform the energy conservation law. [0030] The distinct feature of the present invention is expressing the control variables of the equivalent circuit in a rectangular coordinate. These variables are decomposed into d-q components by an orthogonal projection technique. For each generalized power flow controller, the voltage of the bus connecting the shunt branch is chosen as a reference phasor. The d component is in phase with the reference phasor, whereas the q component leads the reference phasor by 90 degree. For examples, the d-q decomposition on a voltage phasor, V xk =|V xk |∠θ xk , is expressed as: [0000] V xk D =|V rk | cos(θ rk −θ s1 ); V xk Q =|V rk | sin(θ rk −θ s1 )  eq. (1) [0000] where θ s1 , is the phase angle of the voltage at bus s 1 . The superscripts “D” and “Q” symbolize the d-q components of the corresponding variables, subscript “k” is the index of the VSC. The subscript “x” can be replaced with “s”, “r”, “sh” or “ser” to represent variables related to the sending-end, receiving-end, shunt branch and series branch, respectively. The d-q decomposition of a current phasor can be performed in a similar way. [0031] The steady-state model of the generalized power flow controller can be incorporated into a Newton-Raphson power flow algorithm by replacing the generalized power flow controller with equivalent loads at the ends connected with the power grid. By the definition of the complex power, the equivalent load of the shunt branch is: [0000] [ P s   1 Q s   1 ] = [  V s   1  0 0 -  V s   1  ]  [ I sh D I sh Q ] , . eq .  ( 2 ) [0000] where I sh D and I sh Q are the d-q current components of the shunt branch. The equivalent load at the receiving-end of each series branch is set to achieve a power flow control objective as, [0000] [ P rk Q rk ] = - [ P linek ref Q linek ref ] ,  k = 2 , Λ , n , eq .  ( 3 ) [0000] where n is the total number of VSCs, P linek ref and Q linek ref are the reference commands of the active and reactive power from the receiving-end of the kth series branch toward the connected transmission line. The equivalent load at the sending-end of the kth series branch is, [0000] [ P sk Q sk ] = - [ V sk D V sk Q V sk Q - V sk D ]  [ I serk D I serk Q ] ,  k = 2 , Λ , n , eq .  ( 4 ) [0000] where I serk D and I serk Q are the d-q current components of the kth series branch, which can be obtained explicitly as: [0000] [ I serk D I serk Q ] = - 1 V rk 2  [ V rk D V rk Q V rk Q - V rk D ]  [ P rk Q rk ] . [0000] Balancing the active power transfer among VSCs is a main function of VSC 1 . The remaining capacity of VSC 1 can provide the reactive power compensation to regulate the voltage magnitude of the connected bus at a fixed level. Therefore, the voltage magnitude at the bus connecting the shunt branch can be set to achieve a voltage magnitude control objective, [0000] | V s1 |=V s1 ref ,  eq. (5) [0000] where V s1 ref is the desired voltage magnitude at the bus s 1 . Under the lossless assumption of the VSCs, the sum of the active power generated by the VSCs must equal to zero. Therefore, the active power generated by the VSCs must be constrained by an active power balance equation, [0000] P dc = P sh + ∑ k = 2 n  P serk = 0 , eq .  ( 6 ) [0000] where P sh is the active power generated from the equivalent voltage source of the shunt branch, and P serk is the active power generated from the equivalent voltage source of the kth series branch, After simple algebra manipulations, P sh and P serk , can be expressed as: [0000] P sh =I sh D V s1 D +( I sh D 2 +I sh Q 2 ) R sh [0000] P serk =I serk D ( V rk D −V sk D )+ I serk Q ( V rk Q −V sk Q )+( I serk D 2 +I serk Q 2 ) R serk [0000] Each of STATCOM, UPFC, GUPFC and the generalized power flow controller has different numbers of series VSCs. However, they are in common by having one shunt VSC. Consequently, UPFC, STATCOM and GUPFC can be regarded as a subdevice of the generalized power flow controller. For example, if the shunt branch and series branches share the same sending-end bus, ie. bus s 1 , s 2 and s n connect together, the foregoing derivations can be applied to the GUPFC. Similarly, UPFC has only one series branch, set n=2 in Eq (6) in a UPFC application. Furthermore, because the STATCOM has no series branch, the summation part of Eq (6) is omitted, ie. Eq. (6) becomes P dc =P sh , in a STATCOM application. [0032] In the present invention, regardless of the number of series VSCs, and whether the shunt branch and the series branch share the same sending-end or not, the power flow solution can be found under the same procedures. That is, the present invention can be utilized to calculate the power flow solution of a power grid embedded with STATCOM, UPFC, GUPFC and the generalized power flow controller. [0033] The power flow solution can be obtained by solving power flow equations, which is a set of nonlinear equations describing the power balance at each bus of a power grid. The Newton-Raphson power flow algorithm is an iterative procedure to solve power flow equations. The iterative formula of the algorithm is expressed as, [0000] x i+1 =x (i) −[J ( x (i) )] −1 f ( x (i) ),  eq. (7) [0000] where x is a state vector, f(x) is a mismatch vector, and i means the ith iteration. The elements of the state vector are called state variables which include the voltage magnitudes and the phase angles of buses of a power grid. The elements of the mismatch vector include the net active and reactive power flowing into each bus, and the other constraints of the power system. J is a corresponding Jacobian matrix which is formed by the first-order partial derivatives of the mismatch vector. After considering the equivalent loads of the generalized power flow controller, the mismatch vector is modified as: [0000] f′=f+Δf GUPFC ,  eq. (8) [0000] where Δf GUPFC =[Δf bus |Δf control ] T =[P s1 Q s1 P sk Q sk P rk Q rk | P dc ] T , The first part of Δf GUPFC , Δf bus , relates to the equivalent loads at the ends of the generalized power flow controller. The elements of Δf bus are added to the corresponding position of f. The second part of Δf GUPFC , Δf control , is the added constraints introduced by the generalized power flow controller. The element of Δf control augments the size of the mismatch vector. Therefore, the length of f′ is longer than that of f by 1. The elements of Δf GUPFC have been derived in eq. (2), (3), (4) and (6). [0034] With regard to the state vector of the iteration formula, Instead of selecting the voltage magnitudes and phase angles as state variables, the d-q current components of the shunt branch have been chosen as state variables. Hence, elements of the state vector associated with the generalized power flow controller are expressed as: [0000] x GUPFC =[x bus |x control ] T =[θ s1 θ sk |V sk |θ rk |V rk ||I sh D I sh Q ] T ,  eq. (9) [0000] where x bus consists of the original state variables relevant to the generalized power flow controller, and x control consists of the added state variables introduced by the generalized power flow controller. Because |V s1 | is regulated by I sh Q at a fixed voltage level, |V s1 | has been omitted from x bus . The elements of x control augments the size of the original state vector. Thus, one element is omitted and two new elements are appended to the state vector. The length of the state vector is increased by one after embedding the generalized power flow controller. The Jacobian matrix is also modified according to the first-order partial derivatives of f′ as: [0000]  J ′ = J + Δ   J GUPFC ,  Eq .  ( 10 )   where Δ   J GUPFC = [ 0 0 0 0 0 ∣ ∂ P s   1 ∂ I sh D ∂ P s   1 ∂ I sh Q 0 0 0 0 0 ∣ ∂ Q s   1 ∂ I sh D ∂ Q s   1 ∂ I sh Q ∂ P sk ∂ θ s   1 ∂ P sk ∂ θ sk ∂ P sk ∂ V sk ∂ P sk ∂ θ rk ∂ P sk ∂ V rk ∣ 0 0 ∂ Q sk ∂ θ s   1 ∂ Q sk ∂ θ sk ∂ Q sk ∂ V sk ∂ Q sk ∂ θ rk ∂ Q sk ∂ V rk ∣ 0 0 0 0 0 0 0 ∣ 0 0 0 0 0 0 0 ∣ 0 0 - - - - - ⊣ - - ∂ P d   c ∂ θ s   1 ∂ P d   c ∂ θ sk ∂ P d   c ∂ V sk ∂ P d   c ∂ θ rk ∂ P d   c ∂ V rk ∣ ∂ P d   c ∂ I sh D ∂ P d   c ∂ I sh Q ] [0035] The upper left part of ΔJ GUPFC adds to the corresponding position of the original Jacobian matrix J. The other parts of ΔJ GUPFC augment the size of J. Since P r2 □Q r2 □P rk and Q rk are constants, the elements of ΔJ GUPFC in the fifth and sixth rows are all zeros. Because the length of the mismatch vector and the state vector are both increased by one, the size of J′ is bigger than J by one row and one column. [0036] After modifying the mismatch vector and Jacobian matrix, the iterative formula for updating the state vector becomes [0000] x (i+1) =x (i) −[J′ ( x (i) )] −1 f′ ( x (i) )  eq. (11) [0037] When the state vector converges within a specified tolerance, the equivalent voltage of shunt VSC can be recovered from I sh D and I sh Q . Simple manipulations yield the d-q components of the equivalent voltage of the shunt VSC, [0000] [ V sh D V sh Q ] = [ R sh - X sh X sh R sh ]  [ I sh D I sh Q ] + [  V s   1  0 ] . Eq .  ( 12 ) [0000] The equivalent voltages of the series VSCs can be calculated explicitly by: [0000] [ V serk D V serk Q ] = [ R serk - X serk X serk R serk ]  [ I serk D I serk Q ] + [ V rk D - V sk D V rk Q - V sk Q ] ,  k = 2 , Λ , n . Eq .  ( 13 ) [0000] Finally, the polar form of the equivalent voltage of the shunt VSC and the series VSC can be obtained by: [0000]  V sh   ∠   θ sh = V sh D 2 + V sh Q 2  ∠  ( tan - 1  V sh Q V sh D + θ s   1 ) Eq .  ( 14 )  V serk   ∠   θ serk = V serk D 2 + V serk Q 2  ∠  ( tan - 1  V serk Q V serk D + θ s   1 ) Eq .  ( 15 ) [0038] Under the assumption of known generations and loads, the basic power flow solutions, including voltages of all buses in the power grid and the equivalent voltages of the shunt and series VSCs of the generalized power flow controller, can be find by using the disclosed method, and the detail power flow solutions, including the active and reactive power flows into each transmission line, reactive power output of each generator, can be determined by using the basic power flow solution together with the fundamental circuit theory. A summary of procedures to calculate the power flow solution of a power grid embedded with the generalized power flow controller is depicted in FIG. 6 . Step 301 : set the initial value of the state vector, wherein the elements of the state vector, called state variables, comprising the voltage magnitudes of all buses excluding the bus connected to the shunt branch of the generalized power flow controller, the phase angles of all buses, the d-q components of the shunt branch current of the generalized power flow controller; the voltage magnitude of each bus initially sets to 1.0 p.u., the phase angle of each bus, the d and q components of the shunt branch current of the generalized power flow controller all initially set to 0. Step 302 : construct the mismatch vector, f of a power grid ignoring the generalized power flow controller. Step 303 : establish the corresponding Jacobian matrix J using the first order derivatives of the mismatch vector f obtained in step 302 . Step 304 : perform a d-q decomposition on the voltage of the receiving-end of each series branch by eq. (1). The d-q decomposition uses the voltage of the bus connected to shunt branch of the generalized power flow control as a reference phasor. The d component, V rk D , is in phase with the reference phasor, whereas the q component, V rk Q , leads the reference phasor by 90 degree. Step 305 : use eq. (2) to calculate the equivalent load of the shunt branch of the generalized power flow controller. Step 306 : judge whether there exists a series VSC, if it exists, go to step 307 , otherwise, go to step 308 . Step 307 : calculate the equivalent loads at the sending-end and receiving-end of each series branch by using eq. (3) and eq. (4), from the 2 nd to n th series branch, wherein n is the number of VSCs. Step 308 : use eq. (6) to calculate the total active power generated from VSCs, P dc . Step 309 : modify the mismatch vector by using eq. (8). Step 310 : modify the Jacobian matrix by using eq. (10). Step 311 : substitute the modified mismatch vector and modified Jacobian matrix into eq. (11) to update the state vector. Step 312 : judge whether the state vector converges within specified tolerance. If it does not, go back to step 302 . Otherwise, proceed to step 313 . Step 313 : calculate the equivalent voltages of the VSCs by using use eq. (14) and eq. (15). Step 314 : calculate the power flow solution, which includes the voltage of each bus, the active and reactive power flow of each transmission line, the reactive power generated from each generator. [0053] Simulating several test systems embedded with STATCOM, UPFC, GUPFC and the generalized power flow controller has been performed to validate the present invention. The descriptions of the test systems are as follows: Case 1: IEEE 300-bus test system without installing FACTS controller, referred to as a base case. This case provides a comparison basis with other cases. Case 2: Similar to Case 1, except that it has been installed with one additional GUPFC. The GUPFC has one shunt branch and three series branches. The shunt branch is in parallel with bus 37 to control its voltage magnitude. The series branches are in series with line 37 - 49 (the transmission line linking bus 37 and bus 49 ), line 37 - 89 and line 37 - 40 , respectively, to control their active and reactive power flow. Case 3: Similar to Case 2 except that it has been installed with one additional generalized power flow controller, it is referred to as GPFC. GPFC has one shunt branch and two series branches. The shunt branch is in parallel with bus 102 to control its voltage magnitude. The series branches are in series with line 102 - 104 and line 103 - 105 , respectively, to control their active and reactive power flow. Case 4: Similar to Case 3 except that it has been installed with one additional UPEC. The UPFC has one shunt branch and one series branch. The shunt branch is in parallel with bus 7 to control its voltage magnitude. The series branch is in series with line 7 - 131 to control its active and reactive power. Case 5: Similar to Case 4 except that it has been installed with one additional STATCOM. The STATCOM has one shunt branch, and it is in parallel with bus 81 to control its voltage magnitude. [0059] In the above test cases, assuming the coupling transformers have the same impedances as 0.01+j0.05 p.u. The allowable tolerance of Newton-Raphson algorithm is set to 10 −12 . The initial values for the state variables are 1∠0° for the bus voltages, and 0 for I sh D and I sh Q . Table 1 shows the iteration numbers required for obtaining power flow solution in the different test systems. The simulation results showed that incorporating the steady-state model of the generalized power flow controller will not increase the iteration number for obtaining the power flow solution within the same allowable tolerance. [0000] TABLE 1 Iteration numbers required for obtaining power flow solution in the different test systems Case 1 2 3 4 5 Iteration 6 6 6 6 6 numbers [0060] FIG. 7 shows the convergence pattern of state variables of the GUPFC. As shown, the current components I sh Q and I sh D converge to their target values after six iterations, respectively. [0061] Case 3 is designed to demonstrate a distinguishing feature of the present invention. Even through the sending-ends of shunt branch and series branches of the GPFC connect to different buses, the power flow solution converges as rapid as the base case does. FIG. 8 shows the power mismatches at the sending-end and receiving-end buses of the GPFC. After six iterations, the power mismatches are within a tight tolerance, and thus a precise power flow solution is obtained. Therefore, it is well demonstrated that the power flow calculation achieves a rapid convergence characteristic using the steady state model of the generalized power flow controller according to the present invention. [0062] FIG. 9 shows a quadratic convergence pattern of the solution process of Case 4, in which the dotted line is a typical quadratic convergence pattern and the solid line is the convergence curve of Case 4. It reveals that the quadratic convergence characteristic is preserved after embedding one STATCOM, one UPFC, one GUPFC and one generalized power controller into a power grid. [0063] According to the simulation results, the power flow solution of the test cases, installed with STATCOM, UPFC, GUPFC the generalized power flow controller, can converge as rapidly as the base case does. It concludes that incorporating the steady-state model of the generalized power flow controller will not degrade the convergence speed of Newton-Raphson algorithm. [0000] Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.

A method to incorporate the steady-state model of the generalized power flow controller into a Newton-Raphson power flow algorithm is disclosed. The disclosed method adopts a flexible steady-state model of the generalized power flow controller, which can be applied to calculate the power flow solution of a power grid embedded with STATCOM, UPFC, GUPFC and the generalized power flow controller in a single framework. The disclosed method only incorporates the control variables of the shunt voltage sourced converter into the state vector of Newton-Raphson power flow algorithm. The increment of state variables due to incorporating the generalized power flow controller is less than the prior art. Further, the method can preserve the quadratic convergence characteristic of the Newton-Raphson power flow algorithm after embedding the generalized power flow controller into a power grid.

BACKGROUND OF THE INVENTION This invention relates to the measurement of acoustic wave travel time in a fluid medium, with particular application to acoustic pyrometry. Techniques are known for measuring the transit time of acoustic waves from a transmitting location to a receiving location through a fluid medium. Systems using both pulsed waves and continuous waves have been proposed and used in the past for various purposes. In pulsed systems, the transit time is typically measured by noting the time difference between the generation of an acoustic pulse at the transmitting location and the receipt of the same acoustic pulse at the receiving location. In continuous wave systems, the phase difference between the continuous wave at the transmitting location and at the receiving location provides an indirect measurement of the transit time. The transit time thus obtained is typically used to compute the velocity of the acoustic waves in the medium. In acoustic pyrometry, the computed velocity is used to compute the temperature of the fluid using a well-known relationship between acoustic velocity and temperature. For a fuller discussion of the pulsed technique see M. W. Dadd, "Acoustic Thermometry In Gases Using Pulse Techniques", High Temperature Technology, Vol. 1, No. 6, November, 1983. For a fuller discussion of the continuous wave technique see U.S. Pat. No. 4,215,582. While both the pulsed and continuous wave techniques have been found to be useful in many applications, each is demonstrably unsuitable in extremely noisy environments in which erroneous transit time determinations occur due to the masking presence of substantial noise signals and multiple transmission paths for the acoustic wave. One example of such a noisy environment is in the field of industrial boilers, such as modern utility boilers, chemical recovery boilers and refuse boilers. Added to the noise problem is the compounding adverse effect of attenuation of acoustic waves due to scattering of the waves by temperature and velocity gradients (the latter in a moving fluid), and the masking effect of acoustic waves arriving at the receiving location via reflected boundary paths. While many efforts have been made to improve the reliability of acoustic transit time measurement in noisy environments, such efforts have not met with success to date. SUMMARY OF THE INVENTION The invention comprises a method and system for measuring the transit time of acoustic waves between a transmitting location and a receiving location which is highly reliable in operation, even in the extremely noisy and multi-path environments encountered in industrial applications. From a method standpoint, the invention comprises the steps of transmitting acoustic waves through a fluid medium from a transmitting location to a receiving location, generating electrical counterpart signals corresponding to the acoustic waves at the transmitting location and at the receiving location, and determining the transit time of the acoustic waves between the transmitting location and the receiving location by obtaining the impulse response of the electrical signals and determining the point of maximum value corresponding to the arrival time of the acoustic waves at the receiving location. The acoustic waves transmitted through the fluid medium are random continuous or successive bursts each having a plurality of frequencies. For acoustic pyrometry applications, the spectrum of interest is in the band of frequencies between about 100 Hz and about 3,000 Hz. The transit time value can be used to determine a number of parameters, such as the acoustic wave velocity in the fluid medium, the velocity of the medium itself (for a moving medium), and the temperature of the fluid medium. From a system standpoint, the invention comprises a transmitter transducer for generating random acoustic waves for transmission through the fluid medium from a transmitting location to a receiving location, means for producing electrical signals corresponding to the acoustic waves generated by the transducer, a receiver transducer for sensing the acoustic waves arriving at the receiving location and for producing electrical signals corresponding to the received acoustic waves, and computing means for receiving the electrical signals from the producing means and the receiver transducer and for determining the transit time of the acoustic waves between the transmitting location and the receiving location by obtaining the impulse response of the electrical signals and determining the point of maximum value corresponding to the arrival time of the acoustic waves at the receiving location. The transmitting transducer is preferably a pneumatic generator powered by a suitable compressed air source and operated in a time sequential fashion in order to generate continuous or successive bursts of random acoustic waves. The invention has been found to provide particularly improved results in extremely noisy environments, such as those found in industrial boiler applications, while at the same time providing the known advantages attendant with non-invasive acoustic pyrometric techniques. Also, the pneumatic embodiment of the transmitting transducer provides automatic purging of contaminants in the sound generating path without adversely affecting the ability of the system to obtain the transmit time. For a fuller understanding of the nature and advantages of the invention, reference should be had to the ensuing detailed description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating the preferred embodiment of the invention applied to acoustic pyrometry; FIG. 2 is a top plan view of the sound transmitter unit; FIG. 3 is a side elevational view of the sound transmitter unit; FIG. 4 is a rear elevational view of the sound transmitter unit with the cover opened; FIG. 5 is a wiring diagram of the sound transmitter unit; and FIG. 6 is a plot of the impulse response versus time for the system of FIG. 1 applied to a boiler. DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the drawings, FIGS. 1-5 illustrate a preferred embodiment of a system incorporating the invention. As seen in FIG. 1, a pair of boundary walls 11, 12 partially define a volume 14 in which a fluid (not illustrated) of interest is located. In the specific example described below, the fluid is a gas in an industrial boiler, and the parameter of interest is temperature of this gas in the volume 14. In order to determine this temperature, the transit time of acoustic waves between the boundary walls 11, 12 must be measured according to the invention. For this purpose, a pneumatic sound generator 21 is mounted externally of wall 11 in any convenient fashion. The pneumatic sound generator 21 is a unit having two valves schematically indicated by elements 22, 23 and is designed to produce random noise in response to the application of compressed air to an inlet 24 from a suitable source shown). The compressed air is released via valve 23 which comprises an electrically operated solenoid valve (shown in FIG. 4) and which opens and closes in response to control signals supplied by a controller/processor 25. Pneumatic source 21 is coupled to the interior volume 14 via a pipe waveguide 27 having a flared end 28 coupled to a stand-off pipe coupler 29 received in a suitable aperture in wall 11. Check valve 22 (FIG. 4) prevents high pressure in volume 14 from entering the compressed air line and contaminating the compressed air conduit (or otherwise affecting adversely the sound generator 21). The entire system is designed to produce random noise in the frequency band of interest for the acoustic pyrometry application for two major reasons: firstly, the frequency spectrum of paramount interest to acoustic pyrometry is the band of frequencies between 100 Hz and 3,000 Hz; and secondly, it is desired to have as many frequencies as possible generated in the spectrum of interest. Thus, the generator 21 causes a spectrum to be generated with acoustic energy distributed throughout the frequency band of interest. Adjacent the flared end 28 of the pneumatic sound generator 21 is a transducer 30, which is preferably a model 941 piezoelectric transducer available from Scientific Engineering Instruments, Inc. of Sparks, Nev. and which generates electrical signals corresponding to the actual acoustic waves generated by pneumatic generator 21 and injected into the volume 14 via waveguide 27 and coupler 29. These electrical signals are coupled via a cable 31, a preamplifier 32 and cable 26 to the controller/processor 25 and represent a function x(t) required for the signal processing described below. Preamplifier 32 is a dual gain amplifier having a low gain operation and a high gain operation. The low gain operation is used for measuring the high intensity transmitting signal and the high gain operation is used for measuring a received signal. Adjacent boundary wall 12 is a second transducer 34 which is substantially identical to transducer 30 and which generates electrical signals corresponding to the acoustic waves which travel across volume 14 and reach the region of boundary wall 12 adjacent transducer 34. The output of transducer 34 is coupled via a cable 35 and a second preamplifier 36 as a second function y(t) to controller/processor 25. Preamplifier 36 is essentially identical to preamplifier 32 in construction and function, and is used as a high gain preamplifier when used as a receiver amplifier for detecting acoustic; waves generated within the volume 14 by sound generator 21. Similarly, preamplifier 36 is used as a low gain amplifier when sound generator 41 is used as the acoustic wave generator for transmitting waves in the opposite direction towards boundary wall 11. The system shown in FIG. 1 is designed to be symmetric about the vertical plane through the middle of volume 14. Consequently, a second pneumatic source 41, check valve 42, electrically operated air valve 44, pipe waveguide 47 and flared end 48 are provided as shown. It should be understood that such symmetry is not required for all applications, but only those applications in which it is desired to present the capability of generating acoustic waves alternately in opposite directions across volume 14. The acoustic waves generated by source 21 or generator 41 for the high noise acoustic pyrometry application comprise a constant flow or a series of successive bursts of random acoustic waves in the frequency band of interest. The electrical counterparts to the generated acoustic waves developed by transducer 30 and the electrical counterparts to the received acoustic waves generated by transducer 34 are coupled as functions x(t) and y(t), respectively to controller/processor 25 for further processing. This processing proceeds as follows. An impulse response, h (τ) calculation is performed on the signals x(t) and y(t). The impulse response for this system is given as the inverse Fourier Transform of the frequency response function, H(f), that: is, h(τ)=F.sup.-1 [H(f)]=F.sup.-1 [.sup.Sxy /S.sub.xx ] (1) where S xx (f)=averaged autospectral density function or autospectrum of x(t), and S xy (f)=averaged cross spectral density function or cross spectrum between x(t) and y(t) It is well known that the cross-correlation function between x(t) and y(t) is given by R.sub.xy (τ)=F.sup.-1 [S.sub.xy ] (2) As can be seen from a comparison of the two equations, the unit impulse response function resembles a cross-correlation function for an input x(t) with a uniform spectral density of S xx (f)=1. In effect, the unit impulse response provides the cross-correlation function for a uniform input spectral density. Hence, the input data can be computationally pre-whitened over its frequency range using a unit impulse response calculation, which improves the definition of individual propagation paths. This is an extremely important feature in acoustic pyrometry where multi-path signals are generated in the cavity of the furnace. In particular, since the actual input spectrum of the acoustic wave source extends over the relatively wide range noted above and has concentrations of power, improved resolution of flight paths can be achieved by using the unit impulse response computation. As a consequence, it is important to provide as many frequencies as possible throughout the frequency band of interest for acoustic pyrometry since each frequency generates a concentration of power for use by the unit impulse response calculation. FIG. 6 illustrates the result of the impulse response computation for values of x(t) and y(t) obtained in a coal fired 265 megawatt utility boiler presenting an extremely noisy environment. This data was obtained with a pneumatic source 21 capable of generating acoustic waves in excess of 130 dB re: 20μPa @1 m. FIG. 6 is a plot of the magnitude of the impulse response function along the ordinate versus time along the abscissa. The results show a prominent peak at a value of 17.5 milliseconds. Efforts to obtain the same pronounced data using a pulsed chirp system have been found to fail due to the level of noise in the furnace and the presence of multipaths. Other experimental results have established the advantages of the invention in obtaining reliable data in particularly noisy environments. As will now be apparent, the invention provides a method and system for enabling the accurate determination of the transit time between two boundary points in a bounded volume of acoustic waves. From this transit time measurement, the velocity of acoustic waves in the fluid medium between the two boundaries can be computed, and the temperature and velocity of fluid (e.g., gas) can also be computed from the velocity computation using a well known relationship. Further, due to the use of a pneumatic acoustic generator 21 (and alternate, symmetric generator 41), energy levels beyond those available from electromechanical transducers can be achieved, with a corresponding increase in the ability of a system employing acoustic pyrometry to obtain reliable transit time basic information. In addition, by providing transducer 30 adjacent the entrance point of the acoustic waves into the volume 14, a reliable electrical signal replica of the acoustic waves actually injected into the volume 14 can be obtained for subsequent signal processing purposes; and an accurate replica of the received acoustic waves at the receiving wall boundary is obtained by the use of transducer 34. Consequently, intermediate effects produced by pipe 27 and flared end 28 are substantially reduced or eliminated from the information signals x(t) and y(t), which eliminates the necessity of providing compensation factors found in prior art devices using stored waveforms. One important aspect of the invention lies in the use of the pneumatic sound generator 21 as both an acoustic wave generation device and also a contaminant purging device. In known systems, for example, using non-pneumatic generators (such as electro mechanical devices, piezoelectric transducers and the like), in particularly contaminated environments, the wave guides extending between the wave generating element (e.g., a diaphragm) and the entrance to the volume 14 can become contaminated with particulate matter found in the interior of the volume 14 (such as soot) in a coal-fired boiler system. The buildup of the contaminating particles over time leads to a change in the acoustic characteristics of the sound generating system (and the acoustic receiving system as well). Consequently, these units require cleaning at maintenance intervals whose frequency depends on a number of factors affecting the buildup of contamination. With the pneumatic sound generator described above, purging of the acoustic paths leading from the sound source to the volume under investigation is automatically performed along with the generation of the acoustic waves. The importance of this advantage is commensurate with the rate at which contamination accumulates in the system subject to the acoustic testing. For relatively clean environments, either the pneumatic generator described above or conventional acoustic wave generating devices (such as those discussed in the references cited above) may be employed. An another significant advantage of the invention is that the effect of increasing levels of noise, which tend to mask the transit time information, can be compensated for by either increasing the length of time during which the acoustic waves are generated by the transmitter and detected by the receiver or by increasing the number of averages in the frequency domain, especially by providing an increased number of burst repetitions and corresponding impulse response computations when using the burst mode. While the above provides a full and complete disclosure of the preferred embodiment of the invention, various modifications, alternate constructions and equivalents will appear to those skilled in the art. For example, other specific frequencies may be employed in both acoustic pyrometry applications and other applications. Also, other transducers than those specifically identified with respect to elements 30, 34 may be employed, as desired. Therefore, the above descriptions and illustrations should not be construed as limiting the invention which is defined by the appended claims.

The transit time of acoustic waves between a generator and a receiver positioned across a fluid chamber is determined by generating acoustic waves using a self-purging pneumatic sound generator, a transducer adjacent the outlet of the sound generator, and a receiving transducer positioned away from the sound generator outlet so that the acoustic waves received by the receiving transducer pass through a portion of the fluid. The electrical signals generated by the transmitting transducer and the receiving transducer are processed to obtain the impulse response of these electrical signals, and the point of maximum value is determined. This point of maximum value corresponds to the arrival time of the acoustic waves at the receiving location. The transit time determination may be used to calculate the fluid temperature or other parameters. The pneumatic sound generator is driven by a compressed air source so that the generator is automatically purged of any contaminants in the process of generating the random acoustic noise.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation-in-part of U.S. application Ser. No. 13/884,187, filed on May 8, 2013, which is a national stage of International Application No. PCT/EP2011/069691, filed on Nov. 8, 2011, which claims the benefit of U.S. Provisional Application No. 61/435,030, filed on Jan. 21, 2011 and which claims the benefit of Swedish Application No. 1051167-3, filed on Nov. 8, 2010. The entire contents of each of U.S. application Ser. No. 13/884,187, International Application No. PCT/EP2011/069691, U.S. Provisional Application No. 61/435,030, and Swedish Application No. 1051167-3 are hereby incorporated herein by reference in their entirety. TECHNICAL FIELD [0002] The invention disclosed herein generally relates to the field of access control (AC) in computer systems. In particular, it provides devices and methods for efficient evaluation of a plurality of related access requests to an attribute-based access control (ABAC) policy. BACKGROUND OF THE INVENTION [0003] An attribute-based AC (ABAC) policy defines access control permissions based on the attributes of the subject, of the resource, and of the action that the subject is to perform on the resource (e.g., read, write). When the policy is enforced in a computer system or computer network, it controls access to entities in the system or network and thereby influences their state of operation. A resource may be, inter alia, a portion of a personal storage quota, a business unit storage quota, an information retrieval system, a (portion of a) database, an online service, a protected webpage or a physical device. [0004] Functional expressions, in particular rules, in an ABAC policy may be nested hierarchically in a conditional fashion, so that attribute values will influence what further rules are to be applied. To this end, an expression in a policy may evaluate not only to Permit and Deny, but also to Not applicable or a value equivalent to this. An expression may also evaluate to intermediate attribute values, bags of attribute values or assume an error state. In particular the expression may be divided into a target portion, which may trigger a Not applicable state, and a condition portion. Any conflicts arising in the decision making may be settled by way of appropriate combining algorithms, such as permit-overrides and deny-overrides. The final decision for an access control request is the result of a specifically identified top level object. Based on a policy or policy set (unless otherwise indicated, these terms are used interchangeably herein) that covers a broad range of resources and subjects and a given request, it is often possible to obtain a decision by evaluating only a fraction of all functional expressions in the policy. Conversely, it cannot always be ascertained prima facie whether a request contains enough attribute values to allow a successful policy evaluation. [0005] To illustrate, a simple enterprise policy governs use of company printers and company documents (resources). For printers, the printer location is a remote attribute available in a directory. For documents, document classification, type, stage and author are remote attributes available in a database. For users (subjects), their clearance, office location, and nationality are remote attributes available in a directory. The policy (cf. FIG. 2 ) grants a user access to printers if his or her office is in the same location as the printer. For documents, access is allowed if the user has the same or higher clearance as the document classification, except for document on the “draft” stage, which may be accessed by the author only. Furthermore, if the document type is “military”, then only users of domestic nationality may see the document. [0006] There currently exist general-purpose AC languages that have the richness to express fine-grained conditions and conditions which depend on external data. One particular example of an AC language is the eXtensible Access Control Markup Language (XACML) which is the subject of standardization work in a Technical Committee within the Organization for the Advancement of Structured Information Standards (see http://www.oasis-open.org). A policy encoded with XACML consists of functional expressions in attribute values, and the return value (decision) of the policy is one of Permit, Deny, Not Applicable, or Indeterminate. An XACML policy can apply to many different situations, that is, different subjects, resources, actions and environments and may give different results for different combinations of these. The XACML specification defines how a policy is evaluated for a request (or access request), particularly what policy attributes are to be evaluated or, at least, which values are required to exist for a successful evaluation to result. Key characteristics of this evaluation process are that the access request (the query against the policy) must describe the attempted access to a protected resource fully. In practice, it may be that the request is constructed in multiple stages by different components, so that a PEP (Policy Enforcement Point) provides only some initial attribute values and a PDP (Policy Decision Point) or other components can dynamically fetch more attribute values from remote sources as they are needed. [0007] In many situations, it is desirable to automatically derive from an XACML policy a subset which applies to a restricted situation, such as the policy which applies to a specified individual subject or resource, a type of subject or resource, a special action, a certain access location, and so on. The Master's thesis J. Sandberg, “Administrative queries in XACML—feasibility of partial-query evaluation”, Department of Computer and Systems Sciences at Stockholm University and School of Computer Science and Communication, Royal Institute of Technology, Stockholm (2006) (retrievable from http://www.dsv.su.se), which is hereby included by reference, describes evaluation of so-called administrative queries (e.g., “What can user X do?”) to a policy by an approach involving partial evaluation of the policy. Such partial evaluation is based on a partial request in which some attributes have been assigned values and some have been left undefined and yields as output a simplified policy, which is represented in the same form as the original policy but typically evaluates faster since it is expressed as a smaller amount of code and/or contains fewer variable attributes. It is expected that the simplified policy and the original policy provide identical access decision in response to identical requests, provided these requests do not contradict the partial request forming the basis for the partial evaluation. [0008] In section 3.2 of Sandberg's thesis, several simplification rules are derived, including rules governing allowed simplifications of expressions (e.g., rules, policies and policy sets) joined by different combining algorithms, such as deny-overrides and permit-overrides. Examples of these simplification rules include 1. Any expression evaluating to Not applicable is removed. 2. For expressions appearing under a deny-overrides rule combining algorithm: 2.1. If there exists an expression that evaluates to Deny whose target is applicable, remove all other rules and return Deny. 2.2. If there exists an expression that evaluates to Indeterminate whose target is applicable, remove any rule with a Permit effect. 2.3. If there exists an expression that evaluates to Permit whose target is applicable, remove all expressions that evaluate to Indeterminate if their effect is Permit. 2.4. If there exist no expressions with a Deny effect and at least one expression with a Permit effect, remove all other expressions and return Permit. 2.5. If there exist no expressions with a Deny effect and all rules evaluate to Indeterminate, return Indeterminate. 3. For expressions appearing under a permit-overrides policy combining algorithm: 3.1. If there is an expression evaluating to Permit whose target is applicable, remove all other expressions and return Permit. 3.2. If there is an expression evaluated to Deny whose target is applicable, remove all expressions which have returned Indeterminate. [0019] This approach is useful in the context of evaluating administrative queries, wherein it is feasible to verify that the requests to the simplified policy are consistent, i.e., do not contradict, the partial request forming the basis for the partial evaluation. It would be desirable, however, to broaden the applicability of the partial evaluation technique in the field of ABAC policies. SUMMARY OF THE INVENTION [0020] It is an object of the present invention to propose methods and devices for constructing a simplified ABAC policy such that this more faithfully reproduces not only Permit and Deny decisions but also data relating to errors and quasi-errors occurring in the evaluation. It is a further object to extend the applicability of partial evaluation to a broader range of situations. [0021] In a normal evaluation of an access control policy it is possible that there are error conditions or that the policy does not match the access request. Therefore the possible decisions from an evaluation are not just Permit or Deny but also Not applicable or Indeterminate. Also, during normal access control policy evaluation, fragments of the full policy may consist of functional expressions which may evaluate to intermediate values of attribute values, bags of attribute values or Indeterminate. Also, other types of fragments of the policy, used to determinate whether a policy matches the request, may evaluate to intermediate values of Match, NoMatch or Indeterminate. [0022] The result of a partial evaluation is an access control policy which applies to the situation described by the partial request which was used in the evaluation. During partial evaluation, fragments of the policy which are being evaluated may evaluate to simplified fragments, or any of the intermediate results mentioned above. In some cases it is possible to discard intermediate results during partial evaluation. For instance when evaluating a Boolean AND function, any argument of the function which evaluates to “True” may be discarded since the result of the function in that case will depend entirely of the other arguments of the AND function. [0023] However, as the inventors have realized, there are cases in which such intermediate values cannot be discarded. Prior art does not handle these cases. For instance, if the first argument of an AND function results into a simplified expression for that argument and the second argument results in an Indeterminate, the AND expression cannot be simplified further and the Indeterminate of the second argument cannot be discarded. The reason is that the result of partial evaluation must be equivalent to the original AND expression with respect to any access control request which is consistent with the partial request. Since the first argument was simplified to a functional expression, which might take any value True, False or Indeterminate, then the effect of the second argument, which is Indeterminate, depends on the specifics of the access control request being evaluated later on the simplified expression. If the first argument evaluates to “True”, then the Indeterminate of the second argument makes the whole AND expression Indeterminate. On the other hand, if the first argument would evaluate to “False”, then the whole AND expression is false. [0024] The prior art does not have the capability to encode the intermediate values into the resulting expressions. In the prior art, there are two options in a case like this. One option is to fail the partial evaluation process as a whole and return an exception. This is undesirable since in these cases the system relying on the partial evaluation method would fail to function at all. [0025] The other option in prior art is to discard the intermediate values. This will lead to incorrect results for the system which relies on the partial evaluation method. For instance, assume in the example above that we have the following AND expression, with two nested expressions as arguments: [0000] A =AND(expr1,expr2) [0000] Now assume that during partial evaluation expr1 evaluates to a simplified expression called expr1*. Expr2 evaluates to Indeterminate. The resulting simplified AND expression is then [0000] A *=AND(expr1*,Indeterminate) [0000] However, prior art is not capable of encoding this expression into an access control policy. Discarding the Indeterminate leads to another simplified AND expression: [0000] B =AND(expr1*) [0000] Alternatively, the Indeterminate may tentatively be replaced by True or False, which prior art is able to represent: [0000] C =AND(expr1*,True) [0000] D =AND(expr1*,False) [0000] Expr1* will take the same value as expr1 if it is evaluated against an access control request. The following table illustrates the values of A, B, C and D, given the different possible values for expr1/expr1*. [0000] Expr1/expr1* A B C D True Indeterminate True True False False False False False False Indeterminate Indeterminate Indeterminate Indeter- Indeter- minate minate It is to be noted how none of the expressions B, C or D gives the same results as expression A, so this approach fails to meet the basic expectation from partial evaluation, namely, that the simplified expression returns identical results. A system relying on a prior art method for partial evaluation could malfunction at this point, leading to possibly severe complications even if the subsequent requests are found to be consistent with the partial request forming the basis for the partial evaluation. [0026] The example illustrates that the representation used to encode the result of a partial evaluation of an access control policy must be able to encode intermediate results of policy fragments, including error conditions. In the prior art, access control policy languages do not allow for encoding the required intermediate results because such results are not needed in an access control policy which is directly constructed to represent the access control requirements of an organization. For instance, it is not possible in standard XACML to encode results of partial evaluation if certain error conditions occur. [0027] In view of this, the invention provides a method and a system for partially evaluating an ABAC policy, in accordance with the independent claims. By the invention an enriched representation of the simplified policy is created for the purpose of storage, temporary caching or transmission to a different entity or process. The enriched representation includes a dedicated data field associated with an expression, for storing intermediate results of evaluation of the expression itself or an expression subordinate thereto. [0028] In an embodiment, a condition result field operable to store at least a Permit or Deny result from the evaluation of the expression itself is included. Additionally or alternatively, a target result field operable to store at least a Not applicable result, which is a target matching result, from the evaluation of the expression itself. [0029] When the invention is applied to a XACML context, a PolicySet, Policy or Rule will be able to contain a direct defined result within itself. The result may be any valid policy evaluation result, including any error condition, obligation and/or status code. This is needed because the impact of a PolicySet, Policy or Rule may not be known until the results of other PolicySets, Policies or Rules are known. In this case the result must be directly encoded so it is not lost. A PolicySet, Policy or Rule which contains such direct result always evaluates to that result for any access control request or partial request. [0030] A Target expression of a PolicySet, Policy or a Rule can contain a direct matching result of Match, NoMatch or any error condition and status code. This also applies to any nested logical expressions, such as AllOf and AnyOf within the Target. The reason is that a fragment of target may evaluate to an intermediate result, whose significance could depend on the values of other fragments, which might not have been fully evaluated with the given partial request. Therefore this intermediate result must be represented in the simplifled policy resulting from the partial evaluation. [0031] The arguments of functional expressions, including Boolean functions, may consist of a direct defined result on closed form. This defined result may be an attribute value of any type (including values False, True, Permit and Deny), a bag of such attribute values or any error condition with status code. This is needed because there may be other arguments of the function which could not be evaluated such that the value of the function or the significance of the arguments can be determined. In these cases the intermediate values of the arguments of the function must be represented in the simplified policy resulting from the partial evaluation. [0032] Returning to the general ABAC policy context, the new data field allows for several improved simplification rules, including: An expression evaluable only to False is formed in the simplified ABAC policy for each expression in the full ABAC policy which is not completely evaluable under the partial request and which is connected by a Boolean AND function to at least one expression that evaluates under the partial request to False. An expression evaluable only to Indeterminate is formed in the simplified ABAC policy for each expression in the full ABAC policy which is not completely evaluable under the partial request and which is connected by a target-type combining algorithm to at least one expression that evaluates under the partial request to Indeterminate. [0035] An advantage associated with the first of the above simplification rules is that the total result of a policy evaluation is not necessarily false, but may be Indeterminate if the other expression evaluates to Indeterminate, so that the simplified ABAC policy is equivalent to the full ABAC policy. [0036] As used herein, an expression which is not completely evaluable is one that does not evaluate to closed form, such as False, True, Permit, Deny or numerical or textual values, but which requires further argument values for definiteness. In these cases, it is necessary to form at least one functional expression in the simplified policy. [0037] A Boolean AND function is defined in the XACML as an expression with the following properties: AND returns True if there are no argument values. The arguments are evaluated in order, from the first to last, where remaining arguments are not evaluated after a result is found. If an argument evaluates to False, then the function is False. Otherwise, if an argument evaluates to Indeterminate, then the function evaluates to Indeterminate. Otherwise, if all arguments were True, then the function evaluates to True. [0043] Regarding target-type combining algorithms in the XACML context, a Target is a hierarchical conditional expression. The target as a whole evaluates to Match, NoMatch or Indeterminate. The top level of the target is an operation over nested expressions. Each nested expression can return either Match, NoMatch or Indeterminate. The value of the Target as a whole is defined as follows, in the given order, over the possible values of the nested expressions: If the target is empty, then the Target is a Match. If all nested expressions return Match, then the Target is Match. If at least one nested expression is NoMatch, then the Target is NoMatch. Otherwise the Target is “Indeterminate”. [0048] As far as the XACML context is concerned, it is noted that the simplified policy may in some cases be represented in the same form as the original policy. However, the simplified policy may in some cases require a richer representation than standard XACML, possibly including new quasi-error states stemming from the fact that some attributes have not yet been evaluated (substituted). For instance, a situation may arise in which a rule cannot be evaluated for lack of values assumed by the attributes appearing in a condition or target in the rule. The simplified policy may then contain an indication that the rule is indeterminate, that is, temporarily overriding the standard evaluation rules, which may specify for this situation that an evaluation error is to be signaled. This is useful since it may turn out, when combining algorithms in the policy are applied, that the sub-tree in which this rule is located is inconsequential to the policy evaluation, so that this sub-tree may be eliminated from the simplified policy. It is noted that if the simplified policy cannot be represented in standard XACML, evaluation engines adapted for standard XACML may need to be modified to evaluate a simplified policy. [0049] In the XACML context, one distinguishes Not applicable and Indeterminate as error states, wherein Not applicable may typically be returned by an expression in response to a formally correct request which however, by way of its target being different than the intended target of the expression, is not relevant. A request that contains formal deficiencies (e.g., too few arguments, incorrect data types) will, by contrast, be responded to by Indeterminate. By the distinction of a true error state (e.g., Indeterminate) and a quasi-error state (e.g., Not applicable) it becomes possible to collect expressions governing to a broad range of resources, subjects etc., as well as combinations of these, in one policy or policy set. [0050] Furthermore, the inventors have realized that the partial evaluation approach suggested by Sandberg necessitates a continuous verification that any subsequent request to the simplified policy indeed does not contradict the partial request based on which the simplified policy was constructed. Consider the policy [0000] P ( q )=deny-overrides(Rule A ( q ),Rule B ( q )), [0000] wherein RuleB is evaluable to one of Permit, Indeterminate and Not applicable (i.e., the effect of the rule is Permit and it cannot evaluate to Deny) and no assumption is made concerning RuleA. Further consider a partial request q=q1, for which [0000] Rule A ( q 1)=Rule A *( q 1) [0000] Rule B ( q 1)=Indeterminate [0000] where RuleA*(q) is a simplified rule which always gives the same result as RuleA(q) given that the access request is consistent with the partial request q1. [0051] By Sandberg's simplification rule 2.2, a simplified policy according to the prior art would not include RuleB, namely: [0000] P pA ( q )=deny-overrides(Rule A *( q )). [0000] For a request q2, which is such that [0000] Rule A ( q 2)=Not applicable=Rule A *( q 2)[[ ]] [0000] Rule B ( q 2)=Indeterminate, [0000] the original policy will return [0000] P ( q 2)=deny-overrides(Not applicable,Indeterminate)=Indeterminate [0000] provided the deny-overrides algorithm conforms to the XACML standard. However, the policy simplified according to the prior art will contradict the original (or full) policy by returning [0000] P PA ( q 2)=deny-overrides(Not applicable)=Not applicable. [0052] The invention remedies this incoherence by methods and devices according to the independent claims, wherein at least one of the following simplification rules is included: [0053] i) a rule stipulating that an expression evaluable to only Indeterminate is formed in the simplified ABAC policy for each expression in the full ABAC policy which evaluates under the partial request to Indeterminate and which is connected by a deny-overrides combining algorithm to at least one expression that is evaluable to Permit and not completely evaluable under the partial request; [0054] ii) a rule stipulating that an expression evaluable to only Indeterminate is formed in the simplified ABAC policy for each expression in the full ABAC policy which evaluates under the partial request to Indeterminate and which is connected by a permit-overrides combining algorithm to at least one expression that is evaluable to Deny and not completely evaluable under the partial request. [0055] Preferably, said at least one expression that evaluates to Indeterminate is located at the same level of the full policy as the expression which evaluates to Permit (rule i) or Deny (rule ii), respectively. As used herein, an expression may refer to a rule, a policy or a policy set. [0056] Continuing the example above, the invention simplifies the full policy into: [0000] P inv ( q )=deny-overrides(Rule A *( q ),Rule B *( q )), [0000] where RuleB*(q)=Indeterminate for all requests q, according to rule i. The invention removes the incoherence because: [0000] P inv  ( q   2 ) =  deny  -  overrides   ( Not   applicable , Indeterminate ) =  Indeterminate =  P  ( q   2 ) . [0057] A second example along the same lines may be elaborated in respect of a policy [0000] Q ( q )=permit-overrides(Rule A ( q ),Rule B ( q )), [0000] wherein RuleA is evaluable to one of Deny, Indeterminate and Not applicable (i.e., the effect of the rule is Deny) and RuleB is arbitrary. Essentially, the second example may be obtained by substituting “deny” for “permit” and vice versa throughout. When this policy Q forms the basis for the construction of an equivalent simplified policy, simplification rule ii is applicable. [0058] According to one embodiment, a system is operable to perform partial evaluation in order to construct a simplified policy for a set of attributes according. The system comprises a first storing means operable to store all policies for all sets of attributes. The system also comprises a partial request generation means operable to construct a partial request comprising a subset of said set of attributes via a policy information means operable to handle said set of attributes. Furthermore, the system also comprises a partial evaluation means connected to the first storing means, to the partial request generation means, to a second storing means operable to store simplified policies, and to the policy information means. The partial request means is also operable to send a partial request to the partial evaluation means, which in turn is operable to perform partial evaluation against the policy stored in the first storing means, resulting in a simplified policy, which is stored in said second storing means. [0059] The main advantage with this system is that it is possible to derive a policy subset which applies to a restricted situation. A further advantage in this context is achieved if each set of attributes is a set of resource attributes, subject attributes, action attributes, environment attributes, or a combination of two or more of these alternatives. Furthermore, it is an advantage in this context if the system also comprises an input means connected to the first storing means, and operable to input a new policy or to amend a policy in the first storing means. A further advantage in this context is achieved if the first storing means and the second storing means each is in the form of a database, a file, a directory, or a combination of these alternatives. Furthermore, it is an advantage in this context if each of the attributes is either present, not present, or undefined. [0060] In a further embodiment, a method for performing partial evaluation in order to construct a simplified policy for a set of attributes is performed with the aid of a system. The method comprises the steps: with the aid of a partial request generation means, comprised in the system, to construct a partial request from the set of attributes via a policy information means, comprised in the system; to send the partial request to a partial evaluation means, comprised in the system; with the aid of a first storing means, comprised in the system, to store all policies for all sets of attributes; to perform partial evaluation against the policy stored in the first storing means, resulting in a simplified policy; and with the aid of a second storing means, comprised in the system, to store the simplified policy. The main advantage with this method is that it is possible to derive a policy subset which applies to a restricted situation. A further advantage in this context is achieved if each said set of attributes is a set of resource attributes, subject attributes, action attributes, environment attributes, or a combination of two or more of these alternatives. [0066] Furthermore, it is an advantage in this context if the method also comprises the step: with the aid of an input means, comprised in the system and connected to the first storing means, to input a new policy, or to amend a policy in the first storing means. [0068] A further advantage in this context is achieved if each of the attributes is either present, not present, or undefined. [0069] Furthermore, it is an advantage in this context if the step to perform partial evaluation is performed by substituting the attributes which are present in the partial request with values into the policy. [0070] It is noted that the invention relates to all combinations of features, even if these are recited in mutually different claims. BRIEF DESCRIPTION OF THE DRAWINGS [0071] Embodiments of the invention will now be described with reference to the accompanying drawings, on which: [0072] FIG. 1 is a block diagram of the XACML architecture according to prior art; [0073] FIG. 2 is a block diagram of a system operable to perform partial evaluation in order to construct a simplified policy for a set of attributes according to the present invention; [0074] FIG. 3 is a flow chart of a method for performing partial evaluation in order to construct a simplified policy for a set of attributes according to the present invention; [0075] FIG. 4 schematically shows a number of computer program products according to the present invention; and [0076] FIG. 5 is schematically shows a functional expression in a policy. DETAILED DESCRIPTION OF EMBODIMENTS [0077] In FIG. 1 there is disclosed a block diagram of the XACML architecture 200 , although simplified, according to the prior art. As stated before, XACML is an access control policy language. An attempt to access a resource 202 is described in terms of a “Request”, which lists attributes of the subject 204 , the resource 202 , the action and the environment 206 . Most kinds of “facts” about the subject 204 , the resource 202 , the action and the environment 206 can be described in terms of attributes. An attribute is an identifier, a data type and a value. It can also be described as a variable with a name (the identifier), a data type and a value. The request is constructed by a Policy Enforcement Point, PEP 208 . The purpose of a PEP 208 is to guard access to a resource 202 and only let authorized users through. The PEP 208 itself does not know who is authorized; rather it submits the request to a Policy Decision Point, PDP 210 , which contain policies about which requests that shall be permitted respective denied. The PDP 210 evaluates the policies, and returns a permit/deny response to the PEP 208 . The PEP 208 then either lets the access proceed or stops it. [0078] The fundamental purpose with this architecture is to establish separation of concerns, that is, to differentiate between policy decision making and policy enforcement. Enforcement is by its nature specific to a particular resource 202 , while a decision engine can be made general purpose and reusable. In general policies can be nested in a tree form. Different policies are combined using so called combining algorithms which define which policy takes precedence over another. [0079] In FIG. 2 there is disclosed a block diagram of a system operable to perform partial evaluation in order to construct a simplified policy for a set of attributes 12 according to the present invention. The system comprises a first storing means 14 operable to store all policies for all sets of attributes 12 . Furthermore, the system also comprises a partial request generation means 16 operable to construct a partial request comprising a subset of the set of attributes 12 via a policy information means 22 operable to handle the set of attributes 12 . [0080] As is apparent in FIG. 2 , the policy information means 22 is connected to the partial request generation means 16 . The system also comprises a partial evaluation means 18 connected to the first storing means 14 , to the partial request generation means 16 , to a second storing means 20 , and to the policy information means 22 . The second storing means 22 is operable to store simplified policies. Furthermore, the partial request generation means 16 is also operable to send a partial request to the partial evaluation means 18 , which in turn is operable to perform partial evaluation against the policy stored in the first storing means 14 . The result of the partial evaluation is a simplified policy, which is stored in the second storing means 20 . [0081] According to a preferred embodiment of the system 10 , each set of attributes 12 is a set of resource attributes, subject attributes, action attributes, environment attributes, or a combination of two or more of these alternatives. [0082] According to another preferred embodiment, the system also comprises an input means 24 connected to the first storing means 14 . The input means 24 is operable to input a new policy, or to amend a policy in the first storing means 14 . [0083] Furthermore, according to another alternative the first storing means 14 and the second storing means each is in the form of a database, a file, a directory, or a combination of these alternatives. The attributes can be partitioned into attributes which are present, attributes which are not present and attributes which are undefined. Since these three sets partition the set of possible attributes, it is necessary to only define two of them and the third is implied. Typically, the set of attributes which are present and the set of undefined attributes are explicitly listed in an actual request, but this need not always to be the case. [0084] In FIG. 3 there is disclosed a flow chart of a method for performing partial evaluation in order to construct a simplified policy for a set of attributes 12 (see FIG. 2 ) according to the present invention. The method is performed with the aid of a system (see FIG. 2 ). The method begins at block 50 . The method continues, at block 52 , with the step: with the aid of a partial request generation means 16 , comprised in the system 10 , to construct a partial request from the set of attributes 12 via a policy information means 22 , comprised in the system 10 . Thereafter, the method continues, at block 54 , with the step: to send the partial request to a partial evaluation means 18 comprised in the system 10 . The method continues, at block 56 , with the step: with the aid of a storing means 14 , comprised in the system 10 , to store all policies for all sets of attributes 12 . Thereafter, the method continues, at block 58 , with the step: to perform partial evaluation against the policy stored in the first storing means 14 , resulting in a simplified policy. The method continues, at block 60 , with the step: with the aid of a second storing means 20 , comprised in the system 10 , to store the simplified policy. The method is completed at block 62 . [0085] According to a preferred embodiment of the method, each set of attributes 12 is a set of resource attributes, subject attributes, action attributes, environment attributes, or a combination of two or more of these alternatives. [0086] According to another embodiment, the method also comprises the step: with the aid of an input means 24 , comprised in the system and connected to the first storing means 14 , to input a new policy, or to amend a policy in the first storing means 14 . [0088] Furthermore, the attributes can be partitioned into attributes which are present, attributes which are not present and attributes which are undefined. Since these three sets partition the set of possible attributes, it is necessary to only define two of them and the third is implied. Typically, the set of attributes which are present and the set of undefined attributes are explicitly listed in an actual request, but this need not always to be the case. [0089] According to a preferred embodiment of the method, the step to perform partial evaluation is performed by substituting the attributes which are present in the partial request with values into the policy. [0090] Partial evaluation is evaluation of XACML against a request which contains undefined attributes. The parts of the policy tree which refer to the defined attributes can be evaluated as normally, while the parts which refer to undefined attributes are left unevaluated. The result of a partial evaluation is either a permit/deny, in case the defined attributes alone were sufficient to reach a definite conclusion, or a simplified policy in case the policy references undefined attributes. In general, by defining the restricted situation in terms of a partial request with the defining attributes of the situation, and other attributes undefined, the partial evaluation mechanism in general can be used to derive a policy subset/simplified policy which applies to the restricted situation. The policy subset/simplified policy will produce the same result as the full policy for each request which is consistent with the partial request used to derive the policy subset/simplified policy. [0091] In FIG. 4 , computer program products 102 1 , . . . , 102 n according to the present invention are schematically shown. In FIG. 4 , n different digital computers 100 1 , . . . , 100 n are shown, where n is an integer. In FIG. 4 , n different computer program products 102 1 , . . . , 102 n are here shown in the form of compact discs. The different computer program products 102 1 , . . . , 102 n are directly loadable into the internal memory of the n different computers 100 1 , . . . , 100 n . Each computer program product 102 1 , . . . , 102 n comprises software code portions for performing all the steps according to FIG. 3 , when the product/products 102 1 , . . . , 102 n is/are run on the computers 100 1 , . . . , 100 n . [0092] In the upper portion of FIG. 5 , there is illustrated a portion of a policy tree containing functional expressions E 1 , E 2 , E 3 , E 4 . The expressions E 2 , E 3 , E 4 , which are on the same level, are connected by a combination algorithm included in expression E 1 , which may receive inputs data from each of the three other expressions. The lower portion of FIG. 5 shows in more detail expression E 2 , which receives as input attribute values v 1 , v 2 , . . . , which are supplied to condition evaluation unit 510 and target evaluation unit 520 . While the condition evaluation unit 510 is configured to return, for a formally correct set of input data, a decision to Permit or Deny, the target evaluation unit 520 determines whether the expression E 2 is applicable at all. As such, the output of the target evaluation unit 520 takes precedence over that of the condition evaluation unit 510 , which has been symbolically shown in that the target evaluation unit 520 actuates a switch 530 operable to output from the expression E 2 either the output of the condition evaluation unit 510 (as shown in the figure) or a Not applicable output (by setting the switch in the other position). [0093] In accordance with the invention, the expression E 2 includes a condition result memory 511 and a target result memory 512 so that evaluation results may be stored when the expression is included in a simplified policy. The memories 511 , 512 may be embodied as dedicated memories, as memory positions in a shared memory, as data fields in a predefined policy format for transmission or storage. [0094] As a variation to this, the memories 511 , 512 may be replaced by a total result memory 540 for storing the final output of the expression E 2 . [0095] As another variation, the memories 511 , 512 and 540 may be replaced or supplemented by an argument memory 550 for storing the output of a further expression, subordinate to expression E 2 , which supplies the input to expression E 2 . [0096] In XACML, a PolicySet or a Policy may contain a Target and zero or more nested PolicySets or Policies in the case of a PolicySet, or Rules in the case of a Policy. If there is no Target, then the PolicySet or Policy behaves as if there was a Target which is “Match”. There is a policy or rule combining algorithm which decides which of the nested elements determines the result of the PolicySet or Policy as a whole. The result is determined as follows, in the given order: If the Target is Match, then the result is defined by the combining algorithm If the Target is NoMatch, then the result is NotApplicable If the Target is Indeterminate, then the result is Indeterminate [0100] Note that for any combining algorithm, there is a defined partial evaluation function. The specifics of this function depends on the combining algorithm. Since there may be any number of combining algorithms, as users may define their own algorithms, we do not define any specific algorithm for partial evaluation of a combining algorithm. We just assume that the combining algorithm can be evaluated partially, where the inputs to the partial evaluation are the nested elements of the PolicySet or Policy and the output of the partial evaluation is either a defined decision in the form of Permit, Deny, NotApplicable or Indeterminate, or a list of simplified nested elements for the PolicySet or Policy. [0101] In XACML, a rule contains an Effect, which is either Permit or Deny. A rule may contain a Target. A rule may also contain a Condition, which is a functional expression of arbitrary form, except that it returns a Boolean value. If a rule has no Target, it is treated as if it had a Target which evaluates to Match. A rule with no Condition is treated as if it had a condition which evaluates to True. A Rule is evaluated as follows, in the given order. If the Target is Match and the Condition is True, then the Rule is its Effect. If the Target is Match and the Condition is False, then the Rule is NotApplicable If the Target is Match and the Condition is Indeterminate, then the Rule is Indeterminate If the Target is NoMatch, then the rule is NotApplicable If the Target is Indeterminate, then the rule is Indeterminate EXAMPLES [0107] The following pseudo-code examples are included purely for illustration purposes and are not to be construed as limiting the scope of the present invention. Example 1 [0108] To perform partial evaluation of a Boolean AND function, do the following: 1. Declare Boolean variable “GotSimplifiedExpression”, and set it to false 2. Declare a list of arguments, called SimplifiedArgs, to be used if a simplified expression is to be returned as the result of this function. The list starts empty. 3. For each argument of the AND function, evaluate the argument, giving intermediate result R a. If R is Indeterminate i. If GotSimplifiedExpression is False, then return Indeterminate for the AND function result ii. Otherwise save the Indeterminate R as an intermediate result at the end of the list SimplifiedArgs b. If R is True i. Continue to the next argument c. If R is False i. If GotSimplifiedExpression is False, then return False as the values of the AND function result ii. Otherwise save the False R as an intermediate result at the end of the list SimplifiedArgs d. If R is a simplified expression i. Set GotSimplifiedExpression to True ii. Save the expression R as an intermediate result at the end of the list SimplifiedArgs 4. If GotSimplifiedExpression is False a. Return True 5. Otherwise a. Return a new AND function with the arguments in the list SimplifiedArgs. Example 2 [0127] To perform partial evaluation at the top level of a Target, do the following. 1. Define variable atLeastOneIndeterminate of type MatchResult and set it to null 2. Define a list variable simplifiedTargetElements, which can collect simplified nested target expressions. The list starts as empty. 3. For each nested expression in the Target, evaluate the nested expression, giving a result R of type MatchResult a. If R is a simplified expression, save R in the list simplifiedTargetElements b. If R is NoMatch, then return NoMatch c. If R is Indeterminate, set atLeastOneIndeterminate to R d. If R is Match, then continue to the next nested expression 4. If atLeastOneIndeterminate is not null, and the list simplifiedTargetElements is empty, return atLeastOneIndeterminate 5. If the list simplifiedTargetElements is empty, return Match 6. If atLeastOneIndeterminate is not null, add atLeastOneIndeterminate to the list simplifiedTargetElements [0138] Return a new Target containing the nested expressions in the list simplifiedTargetElements Example 3 [0139] To perform partial evaluation of a PolicySet or a Policy, do the following. 1. Evaluate the Target, which gives the result T. If there is no Target, then T is “Match” 2. If T is NoMatch, then return NotApplicable 3. If T is Indeterminate, then return Indeterminate 4. Declare variable SimplifiedTarget and set it to null 5. If T is a simplified expression, set SimplifiedTarget to T 6. Perform partial evaluation on the combining algorithm, given the result C 7. If SimplifiedTarget is null a. If C is a list of simplified nested elements, return a new PolicySet or Policy with no target and the nested elements given by C b. Otherwise return C 8. Otherwise if SimplifiedTarget is not null a. If C is a list of simplified nested elements, return a new PolicySet or Policy with SimplifiedTarget as the Target and the nested elements given by C b. Otherwise return a new PolicySet or Policy with SimplifiedTarget as the Target and a nested defined decision as given by C Example 4 [0152] To perform partial evaluation of a Rule, do the following. 1. Evaluate the Target, which gives the result T. If there is no Target, then T is “Match” 2. If T is NoMatch, then return NotApplicable 3. If T is Indeterminate, then return Indeterminate 4. Declare variable SimplifiedTarget and set it to null 5. If T is a simplified expression, set SimplifiedTarget to T 6. Perform partial evaluation on the condition, given the result C. If there is no Condition, then C is “True” 7. If SimplifiedTarget is null a. If C is a simplified expression, return a new Rule with no target and the condition given by C and the same effect as the Rule itself b. If C is True, return the Effect of the Rule c. If C is False, return NotApplicable d. If C is Indeterminate, return Indeterminate. 8. Otherwise if SimplifiedTarget is not null: a. If C is a simplified expression, return a new Rule with SimplifiedTarget as the Target and the condition given by C and the same effect as the Rule itself. b. If C is False, return a new Rule with SimplifiedTarget as the Target, no condition and a nested defined decision with NotApplicable. c. If C is True, return a new Rule with SimplifiedTarget as the Target, no condition and the same effect as the Rule itself. d. If C is Indeterminate, return a new Rule with SimplifiedTarget as the Target, no condition and a nested defined decision with the Indeterminate from C. EMBODIMENTS [0169] A computer system may include a subject (e.g., a user terminal) and a resource (e.g., a file, a webpage or a hardware device). The subject's access to the resource is controlled by a guard means (e.g., a server) adapted to evaluate an ABAC policy. A policy storage means, preferably a non-volatile storage, stores data representing an ABAC policy which specifies, in attribute-based form, the permissions which are currently to apply in the computer system. In typical circumstances, the ABAC policy is frequently updated, which is reflected in frequent modifications to the policy data stored in the policy storage means. [0170] Advantageous embodiments of the invention include the following: [0171] 1. A system ( 10 ) operable to perform partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ), said system ( 10 ) comprising a first storing means ( 14 ) operable to store all policies for all sets of attributes ( 12 ), characterized in that said system ( 10 ) also comprises a partial request generation means ( 16 ) operable to construct a partial request comprising a subset of said set of attributes ( 12 ) via a policy information means ( 22 ) operable to handle said set of attributes ( 12 ), a partial evaluation means ( 18 ) connected to said first storing means ( 14 ), to said partial request generation means ( 16 ), to a second storing means ( 20 ) operable to store simplified policies, and to said policy information means ( 22 ), wherein said partial request generation means ( 16 ) also is operable to send a partial request to said partial evaluation means ( 18 ), which in turn is operable to perform partial evaluation against the policy stored in said first storing means ( 14 ), resulting in a simplified policy, which is stored in said second storing means ( 20 ). [0172] 2. A system ( 10 ) operable to perform partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to embodiment 1, characterized in that each set of attributes ( 12 ) is a set of resource attributes, subject attributes, action attributes, environment attributes, or a combination of two or more of these alternatives. [0173] 3. A system ( 10 ) operable to perform partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to embodiment 1, or 2, characterized in that said system ( 10 ) also comprises an input means ( 24 ) connected to said first storing means ( 14 ), and operable to input a new policy or to amend a policy in said first storing means ( 14 ). [0174] 4. A system ( 10 ) operable to perform partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to any one of embodiments 1-3, characterized in that said first storing means ( 14 ) and said second storing means ( 20 ) each is in the form of a database ( 14 ; 20 ), a file ( 14 ; 20 ), a directory ( 14 ; 20 ), or a combination of these alternatives. [0175] 5. A system ( 10 ) operable to perform partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to any one of embodiments 1-4, characterized in that each of the attributes is either present, not present or undefined. [0176] 6. A method for performing, with the aid of a system ( 10 ), partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ), said method comprises the steps: with the aid of a partial request generation means ( 16 ), comprised in said system ( 10 ), to construct a partial request from said set of attributes ( 12 ) via a policy information means ( 22 ), comprised in said system ( 10 ); to send said partial request to a partial evaluation means ( 18 ), comprised in said system ( 10 ); with the aid of a first storing means ( 14 ), comprised in said system ( 10 ), to store all policies for all sets of attributes ( 12 ); to perform partial evaluation against the policy stored in said first storing means ( 14 ), resulting in a simplified policy; and with the aid of a second storing means ( 20 ), comprised in said system ( 10 ), to store said simplified policy. [0182] 7. A method for performing partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to embodiment 6, characterized in that each said set of attributes ( 12 ) is a set of resource attributes, subject attributes, action attributes, environment attributes, or a combination of two or more of these alternatives. [0183] 8. A method for performing partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to embodiment 6, or 7, characterized in that said method also comprises the step: with the aid of an input means ( 24 ), comprised in said system ( 10 ) and connected to said first storing means ( 14 ), to input a new policy, or to amend a policy in said first storing means ( 14 ). [0185] 9. A method for performing partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to any one of embodiments 6-8, characterized in that each of said attributes is either present, not present, or undefined. [0186] 10. A method for performing partial evaluation in order to construct a simplified policy for a set of attributes ( 12 ) according to any one of embodiments 6-9, characterized in that said step to perform partial evaluation is performed by substituting said attributes which are present in said partial request with values into said policy. [0187] 11. At least one computer program product ( 102 1 , . . . , 102 n ) directly loadable into the internal memory of at least one digital computer ( 100 1 , . . . , 100 n ), comprising software code portions for performing the steps of embodiment 6 when said at least one product ( 102 1 , . . . , 102 n ) is/are run on said at least one computer ( 100 1 , . . . , 100 n ). CLOSING REMARKS [0188] Further embodiments of the present invention will become apparent to a person skilled in the art after studying the description above. In particular, the skilled person will realize in the light of this disclosure what additional adaptations are required in order for existing policy formats and policy evaluation systems to be able to benefit from partial evaluation in general situations. Such generalization work may proceed by a systematic survey of existing constructs (in particular, available functional expressions, such as rules, policies and policy sets, as well as their combining algorithms), wherein several situations, which may arise when partial evaluation leads to combinations of error, quasi-error and/or Permit/Deny results, are considered with a view to maintaining consistency between the simplified ABAC policy and the full ABAC policy. [0189] Even though the present description and drawings disclose embodiments and examples, the invention is not restricted to these specific examples. For instance, the invention can be applied to control access to resources outside the context of computing; as an example, access to the premises in a building can be controlled if suitable identification means (e.g., card readers, biometric sensors, which identify a person as a subject in a guarding system) and actuators (e.g., electrically controllable door locks) are provided and are communicatively connected to a computer system for enforcing the AC policy. Furthermore, the exact order of the steps in a method disclosed above is not an essential feature of the invention unless this is clearly indicated or unless the outcome of a method step depends on input obtained from a different step, which is then necessarily prior in order. Similarly, in a sequence of conditional steps to be executed on an “otherwise” basis, the order of the steps can obviously not be changed arbitrarily. Thus, numerous modifications and variations can be made without departing from the scope of the present invention, which is defined by the accompanying claims. Any reference signs appearing in the claims are not to be understood as limiting their scope. [0190] The systems and methods disclosed hereinabove may be implemented as software, firmware, hardware or a combination thereof. In a hardware implementation, the division of tasks between functional units referred to in the above description does not necessarily correspond to the division into physical units; to the contrary, one physical component may have multiple functionalities, and one task may be carried out by several physical components in cooperation. Certain components or all components may be implemented as software executed by a digital signal processor or microprocessor, or be implemented as hardware or as an application-specific integrated circuit. Such software may be distributed on computer readable media, which may comprise computer storage media (or non-transitory media) and communication media (or transitory media). As is well known to a person skilled in the art, the term computer storage media includes both volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Further, it is well known to the skilled person that communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

Methods and devices for constructing a simplified attribute-based access control policy, which more faithfully reproduces not only Permit and Deny decisions but also data relating to errors and quasi-errors resulting from the evaluation. To this end, the simplified policy includes new data fields for storing intermediate results. Further, improved simplification rules allowing partial evaluation to be used in a broader range of situations.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional application that claims priority of provisional application Ser. No. 60/580,161, filed Jun. 16, 2004, provisional application Ser. No. 60/679,305 filed May 10, 2005, and U.S. non-provisional application Ser. No. 11/153,602 filed Jun. 15, 2005, which are incorporated herein by reference in their entirety. TECHNICAL FIELD This invention relates to a medical device and more particularly to a medical device for the introduction of a stent graft into a human or animal body. BACKGROUND OF THE INVENTION This invention will be generally discussed in relation to deployment of stent grafts into the aorta but it is not so limited and can be applied to other vasculature or other body lumens. The introduction of endovascular techniques for the placement of stent grafts into the vascular of human or animal patient has revolutionized the treatment of vascular diseases. As treatment techniques have improved there is a requirement for deployment devices which can provide a physician with more flexibility and control in placement of stent grafts. The object of this invention is to provide an introducer for a stent graft which will give a physician more control or at least provide the physician with a useful alternative. Throughout this specification the term “distal” with respect to a portion of the aorta, a deployment device or a prosthesis is the end of the aorta, deployment device or prosthesis further away in the direction of blood flow away from the heart, and the term “proximal” means the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. When applied to other vessels similar terms such as caudal and cranial should be understood. Throughout this discussion the term “stent graft” is intended to mean a device which has a tubular body of biocompatible graft material and at least one stent fastened to the tubular body to define a lumen through the stent graft. The stent graft may be bifurcated and have fenestrations, side arms or the like. Other arrangements of stent grafts are also within the scope of the invention. SUMMARY OF THE INVENTION In one form, the invention is said to reside in a stent graft introducer for intraluminal deployment of a stent graft, the introducer comprising a stent graft retention and release mechanism to allow selective release of each end of the stent graft when carried on the introducer, an indwelling catheter extending from a distal end of the introducer to a proximal end of the introducer and passing through the stent graft when retained on the introducer, whereby control of the stent graft can be maintained while allowing access into the lumen of the stent graft by use of the indwelling catheter. Preferably the release mechanism includes a fastening between the stent graft and introducer at both proximal and distal ends of a stent graft retained on the introducer. The stent graft introducer may have a sheath surrounding the deployment catheter and preferably the sheath is a highly flexible sheath. In a further form the invention is said to reside in a stent graft introducer for intraluminal deployment of a stent graft, an introducer having: a guide wire catheter extending from a proximal to a distal end, a nose cone dilator on the proximal end of the guide wire catheter, the nose cone dilator having a proximal end and a distal end and a longitudinal groove therein, a deployment catheter on the guide wire catheter, the guide wire catheter passing through a lumen in the deployment catheter and the deployment catheter being able to move longitudinally and rotationally with respect to the guide wire catheter, a first retention arrangement at the proximal end of the deployment catheter to retain the distal end of a stent graft thereon, a second retention arrangement at the distal end of the nose cone dilator to retain the proximal end of a stent graft thereon, a release arrangement associated with the handle to separately release the first retention arrangement and the second retention arrangement, and an indwelling catheter extending from the handle to the groove in the nose cone dilator. Preferably, each release arrangement includes a trigger wire extending from the retention arrangement to a respective trigger wire grip on the handle, and the trigger wire grips are arranged on the handle so that they can only be released in a selected order. In a preferred form of the invention the stent graft has a distally extending exposed stent and the first retention arrangement for the distal end of the stent graft includes a capsule covering the exposed stent and acting as the first retention arrangement and a trigger wire associated with the capsule which prevents the exposed stent from being released from the capsule until the trigger wire has been removed as discussed earlier. There can be further diameter reducing ties associated with the stent graft when retained on the introducer and the handle including a release arrangement for the diameter reducing ties. The diameter reducing ties comprise loops of suture or other thread material which extend around part of the periphery of the stent graft and are located by a trigger wire and are tightened to reduce the circumference of the stent graft. When released, the stent graft can expand to its full diameter. In a preferred form the stent graft has at least one fenestration such that when the stent graft is deployed in the body lumen such as an aorta fluid communication can occur between the lumen of the stent graft and a branch artery of the lumen. For instance in the case of a stent graft deployed in the aorta of a patient then the fenestration may allow access to the renal, mesenteric or coeliac axis arteries. In the case of a stent graft deployed into the descending aorta the fenestration may be at or adjacent the distal end of the stent graft to allow access to a branch artery. The indwelling catheter would allow access from the thoracic arch such as by a brachial or carotid access. Such a fenestration may be in the form of a scallop at the distal end of the stent graft or may be an aperture in the body of the stent graft. The aperture may be reinforced with a resilient wire ring around its periphery. When the stent graft has been at least partially released the resilient wire ring will cause the fenestration to open to assist with access through the fenestration. Preferably the introducer further comprises an indwelling catheter extending from a distal end of the introducer to a proximal end of the introducer and passing through the stent graft when retained on the introducer. Preferably the indwelling catheter extends through the deployment catheter to the nose cone dilator to be received in the groove therein. Preferably the indwelling catheter extends through the fenestration. In a further form the invention is said to reside in a stent graft introducer for intraluminal deployment of a stent graft, an introducer having: a guide wire catheter extending from a proximal to a distal end, a nose cone dilator on the proximal end of the guide wire catheter, the nose cone dilator having a proximal end and a distal end, a deployment catheter on the guide wire catheter, the guide wire catheter passing through a lumen in the deployment catheter and the deployment catheter being able to move longitudinally and rotationally with respect to the guide wire catheter, a distal retention arrangement a the proximal end of the deployment catheter to retain the distal end of a stent graft thereon and an associated distal release arrangement, a proximal retention arrangement at the distal end of the nose cone dilator to retain the proximal end of a stent graft thereon and an associated proximal release arrangement, the proximal retention arrangement including multiple fastenings between the stent graft and the release mechanism, a first release arrangement associated with the handle to release the distal retention arrangements, a second release arrangement associated with the handle to release the proximal fastenings, each release arrangement including a trigger wire extending from the respective retention arrangement to a trigger wire grip on the handle, the trigger wire grips being arranged on the handle so that they can only be released in a selected order. There can be further diameter reducing ties associated with the stent graft when retained on the introducer and the handle including a release arrangement for diameter reducing ties on the stent graft. In a preferred form of the invention the stent graft has a distally extending exposed stent and the distal retention arrangement includes a capsule to cover the exposed stent and the distal release arrangement includes means to withdraw the capsule from the exposed stent. There can be further included a capsule trigger wire associated with the capsule which engages with the exposed stent within the capsule and prevents the capsule from being removed from the exposed stent until the capsule trigger wire has been removed and there is a respective trigger wire grip on the handle. In a preferred form the stent graft has at least one fenestration at a distal end thereof such that when the stent graft is deployed in the body lumen, such as an aorta, fluid communication can occur between the lumen of the stent graft and a branch artery of the lumen. For instance, in the case of a stent graft deployed in the aorta of a patient then the fenestration may allow access to the renal, mesenteric or coeliac axis arteries. The fenestration may be an aperture through the wall of the stent graft or may be a cut out in an end of the stent graft. The stent graft may comprise a tubular body of a biocompatible graft material and a plurality of stents to define in use a lumen through the stent graft. In an alternative form the invention is said to reside in a stent graft introducer for intraluminal deployment of a stent graft, the introducer comprising a stent graft release mechanism to allow partial release of at least one end of the stent graft when carried on the introducer, whereby control of the stent graft can be maintained while allowing access into the lumen of the stent graft through the partially released at least one end of the stent graft. Preferably the release mechanism includes a fastening between the stent graft and introducer at both proximal and distal ends of a stent graft retained on the introducer and the partial release releases at least part of the fastening at either the proximal or distal end. Preferably the partial release is only a part of the total fastening at either the proximal or distal end and hence because there is still some retention at both the proximal and distal ends of the stent graft, control of the positioning of the stent graft within a body lumen is still possible. In a preferred embodiment retention of either the proximal or distal ends of the stent graft includes at least three fastenings between the stent graft and a release mechanism with the fastening spaced around the periphery of the stent graft and the partial release releases at one of these at least three fastenings thereby releasing part of the end of the stent graft to allow the access as discussed above. In a further form the invention is said to reside in a stent graft introducer for intraluminal deployment of a stent graft, the introducer having proximal and distal stent graft release mechanisms, the proximal release mechanism having at least two fastenings between the stent graft and at least two release mechanisms for the fastenings at the proximal end to allow partial release of part of the proximal end of the stent graft when carried on the introducer, whereby control of the stent graft can be maintained while allowing access into the lumen of the stent graft from the partially released proximal end of the stent graft. In a further form the invention is said to reside in a stent graft introducer for intraluminal deployment of a stent graft, an introducer comprising: a guide wire catheter extending from a proximal to a distal end, a nose cone dilator on the proximal end of the guide wire catheter, the nose cone dilator having a proximal end and a distal end, a deployment catheter on the guide wire catheter, the guide wire catheter passing through a lumen in the deployment catheter and the deployment catheter being able to move longitudinally and rotationally with respect to the guide wire catheter, a first retention arrangement at the proximal end of the deployment catheter to retain the distal end of a stent graft thereon, a second retention arrangement at the distal end of the nose cone dilator to retain the proximal end of a stent graft thereon, a release arrangement associated with the handle to separately release the first retention arrangement and the second retention arrangement, either the first or the second retention arrangement including multiple fastenings between the stent graft and the release mechanism and wherein one of the multiple fastenings can be released independently of the others of the multiple fastenings, a stent graft retained on the introducer, the stent graft comprising at least one fenestration whereby when the stent graft is deployed in a body lumen fluid communication can occur between the lumen of the stent graft and a branch artery of the lumen through the fenestration, an indwelling catheter extending from a distal end of the introducer through the deployment catheter to a proximal end of the stent graft when retained on the introducer, and the indwelling catheter extending through the fenestration. In one embodiment the fenestration comprises a scallop at the distal end of the stent graft. Alternatively the fenestration is an aperture in the body of the stent graft and being reinforced with a resilient wire ring around its periphery. The graft material may be a woven or non-woven fabric such as Dacron or may be a polymeric material such as expandable PTFE. The graft material may alternatively be a naturally occurring biomaterial, such as collagen, particularly a specially derived collagen material known as an extracellular collagen matrix (ECM), such as small intestinal submucosa (SIS) that causes remodelling of host tissue coming into contact therewith. Besides SIS, examples of ECM=s include pericardium, stomach submucosa, liver basement membrane, urinary bladder submucosa, tissue mucosa, and dura mater. The plurality of stents may be self-expanding zig zag stents or may be balloon expandable stents or other forms of stent. U.S. Pat. No. 5,387,235 entitled “Expandable Transluminal Graft Prosthesis For Repair Of Aneurysm” discloses apparatus and methods of retaining grafts onto deployment devices. These features and other features disclosed in U.S. Pat. No. 5,387,235 could be used with the present invention and the disclosure of U.S. Pat. No. 5,387,235 is herewith incorporated in its entirety into this specification. U.S. Pat. No. 5,720,776 entitled “Barb and Expandable Transluminal Graft Prosthesis For Repair of Aneurysm” discloses improved barbs with various forms of mechanical attachment to a stent. These features and other features disclosed in U.S. Pat. No. 5,720,776 could be used with the present invention and the disclosure of U.S. Pat. No. 5,720,776 is herewith incorporated in its entirety into this specification. PCT Patent Publication No. WO 98/53761 entitled “A Prosthesis And A Method And Means Of Deploying A Prosthesis” discloses an introducer for a prosthesis which retains the prosthesis so that each end can be moved independently. These features and other features disclosed in PCT Patent Publication No. WO 98/53761 could be used with the present invention and the disclosure of PCT Patent Publication No. WO 98/53761 is herewith incorporated in its entirety into this specification. U.S. Pat. No. 6,524,335 and PCT Patent Publication No. WO 99/29262 entitled “Endoluminal Aortic Stents” disclose a fenestrated prosthesis for placement where there are intersecting arteries. This feature and other features disclosed in U.S. Pat. No. 6,524,335 and PCT Patent Publication No. WO 99/29262 could be used with the present invention and the disclosure of U.S. Pat. No. 6,524,335 and PCT Patent Publication No. WO 99/29262 is herewith incorporated in its entirety into this specification. U.S. patent application Ser. No. 10/280,486, filed Oct. 25, 2002 and published on May 8, 2003 as U.S. Patent Application Publication No. US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 entitled “Prostheses For Curved Lumens” discloses prostheses with arrangements for bending the prosthesis for placement into curved lumens. This feature and other features disclosed in U.S. patent application Ser. No. 10/280,486, and U.S. Patent Application Publication No. US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 could be used with the present invention and the disclosure of U.S. patent application Ser. No. 10/280,486, and U.S. Patent Application Publication No. US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 is herewith incorporated in its entirety into this specification. U.S. Pat. No. 6,206,931 entitled “Graft Prosthesis Materials” discloses graft prosthesis materials and a method for implanting, transplanting replacing and repairing a part of a patient and particularly the manufacture and use of a purified, collagen based matrix structure removed from a submucosa tissue source. These features and other features disclosed in U.S. Pat. No. 6,206,931 could be used with the present invention and the disclosure of U.S. Pat. No. 6,206,931 is herewith incorporated in its entirety into this specification. U.S. Provisional Patent Application Ser. No. 60/392,682, filed Jun. 28, 2002, U.S. patent application Ser. No. 10/447,406, filed May 29, 2003, and Published on Dec. 18, 2003, as U.S. Patent Application Publication No. US-2003-0233140-A1, and PCT Patent Publication No. WO 03/101518 entitled “Trigger Wires” disclose release wire systems for the release of stent grafts retained on introducer devices. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/392,682, U.S. patent application Ser. No. 10/447,406, and U.S. Patent Application Publication No. US-2003-0233140-A1, and PCT Patent Publication No. WO 03/101518 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/392,682, U.S. patent application Ser. No. 10/447,406, and U.S. Patent Application Publication No. US-2003-0233140-A1, and PCT Patent Publication No. WO 03/101518 is herewith incorporated in its entirety into this specification. U.S. Provisional Patent Application Ser. No. 60/392,667, filed Jun. 28, 2002, and U.S. patent application Ser. No. 10/609,846, filed Jun. 30, 2003, and Published on May 20, 2004, as US Patent Application Publication No. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399 entitled “Thoracic Deployment Device” disclose introducer devices adapted for deployment of stent grafts particularly in the thoracic arch. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/392,667, U.S. patent application Ser. No. 10/609,846, and US Patent Application Publication No. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/392,667, U.S. patent application Ser. No. 10/609,846, and US Patent Application Publication No. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399 is herewith incorporated in its entirety into this specification. U.S. Provisional Patent Application Ser. No. 60/392,599, filed Jun. 28, 2002, and U.S. patent application Ser. No. 10/609,835, filed Jun. 30, 2003, entitled “Thoracic Aortic Aneurysm Stent Graft” disclose stent grafts that are useful in treating aortic aneurysms particularly in the thoracic arch. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/392,599 and U.S. patent application Ser. No. 10/609,835, filed Jun. 30, 2003 could be used with the present invention, and the disclosure are herewith incorporated in their entirety into this specification. U.S. Provisional Patent Application Ser. No. 60/392,599, filed Jun. 28, 2002, and U.S. patent application Ser. No. 10/609,835, filed Jun. 30, 2003, and published on Jun. 3, 2004, as U.S. Patent Application Publication No. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370 entitled “Thoracic Aortic Aneurysm Stent Graft” disclose stent grafts that are useful in treating aortic aneurysms particularly in the thoracic arch. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/392,599, U.S. patent application Ser. No. 10/609,835, and U.S. Patent Application Publication No. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370 could be used with the present invention, and the disclosure of U.S. Provisional Patent Application Ser. No. 60/392,599, U.S. patent application Ser. No. 10/609,835, and U.S. Patent Application Publication No. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370 is herewith incorporated in its entirety into this specification. U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/647,642, filed Aug. 25, 2003, and published on Apr. 15, 2004, as U.S. Patent Application Publication No. US-2004-0073289-A1, and PCT Patent Publication No. WO 2004/017868 entitled “Asymmetric Stent Graft Attachment” disclose retention arrangements for retaining onto and releasing prostheses from introducer devices. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/647,642, filed Aug. 25, 2003, and U.S. Patent Application Publication No. US-2004-0073289-A1, and PCT Patent Publication No. WO 2004/017868 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/647,642, filed Aug. 25, 2003, and U.S. Patent Application Publication No. US-2004-0073289-A1, and PCT Patent Publication No. WO 2004/017868 is herewith incorporated in its entirety into this specification. U.S. patent application Ser. No. 10/322,862, filed Dec. 18, 2002 and published as U.S. Patent Application Publication No. US2003-0120332, and PCT Patent Publication No. WO 03/053287 entitled “Stent Graft With Improved Adhesion” disclose arrangements on stent grafts for enhancing the adhesion of such stent grafts into walls of vessels in which they are deployed. This feature and other features disclosed in U.S. patent application Ser. No. 10/322,862, filed Dec. 18, 2002 and published as U.S. Patent Application Publication No. US2003-0120332, and PCT Patent Publication No. WO 03/053287 could be used with the present invention and the disclosure of U.S. patent application Ser. No. 10/322,862, filed Dec. 18, 2002 and published as U.S. Patent Application Publication No. US2003-0120332, and PCT Patent Publication No. WO 03/053287 is herewith incorporated in its entirety into this specification. U.S. Provisional Patent Application Ser. No. 60/405,769, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/645,095, filed Aug. 23, 2003, and published on Apr. 29, 2004, as U.S. Patent Application Publication No. US-2004-0082990-A1, and PCT Patent Publication No. WO 2004/017867 entitled “Composite Prostheses” discloses prostheses or stent grafts suitable for endoluminal deployment. These prostheses and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/405,769, U.S. Patent Application Ser. No. 10/645,095, and U.S. Patent Application Publication No. US-2004-0082990-A1, and PCT Patent Publication No. WO 2004/017867 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/405,769, U.S. patent application Ser. No. 10/645,095, and U.S. Patent Application Publication No. US-2004-0082990-A1, and PCT Patent Publication No. WO 2004/017867 is herewith incorporated in its entirety into this specification. BRIEF DESCRIPTION OF THE DRAWING This then generally describes the invention but to assist with understanding reference will now be made to the accompanying drawings which show preferred embodiments of the invention. In the drawings: FIG. 1 shows a general view of a deployment device according to one embodiment of the invention; FIG. 2 shows a longitudinal cut-away view of the embodiment shown in FIG. 1 but with the device rotated through 90 degrees on a longitudinal axis; FIG. 3 shows part of the deployment device as shown in FIG. 1 after a first stage of deployment and with a fenestrated stent graft retained thereon; FIG. 3A shows the same view as FIG. 3 except that it shows the other side of the stent graft and deployment device; FIG. 4 shows part of the deployment device as shown in FIG. 1 with an alternative stent graft retained thereon with a scalloped fenestration and an apertured fenestration; FIG. 5 shows a longitudinal cross sectional view showing detail of the sliding handle mechanism of the deployment device of FIG. 1 ; FIG. 6 shows a similar view to that of FIG. 5 except that the handle has been retracted; FIG. 7 shows a detailed view of one embodiment of proximal fastening arrangement for a stent graft onto the deployment device of FIG. 1 ; FIG. 8 shows a cross sectional view along the line 8 B 8 =in FIG. 7 ; FIG. 9 shows a detailed view of one embodiment of a distal retention arrangement for a stent graft onto the deployment device of FIG. 1 ; FIG. 10 shows one embodiment of a stent graft suitable for use with a deployment device according to one embodiment of the invention; FIG. 11 shows a longitudinal cross sectional view of the stent graft of FIG. 10 ; FIG. 12 shows a detail view of the proximal end fastenings of a stent graft onto a deployment device according to one embodiment of the invention; FIG. 13 a detail view of an alternative embodiment of proximal end fastenings of a stent graft onto a deployment device according to the invention; FIG. 14 shows a detail of the proximal end of a stent graft fastened onto a deployment device according to one embodiment of the invention; FIG. 15 shows a detail of the proximal end of a stent graft fastened onto a deployment device according to an alternative embodiment of the invention; FIG. 16 shows the detailed fastening of FIG. 15 but with the stent graft partially released; FIG. 17 shows an alternative embodiment of a stent graft with a scalloped fenestration suitable for use with a deployment device according to one embodiment of the invention; FIG. 18 shows detail of an alternative embodiment of scalloped fenestration; FIG. 19 shows an alternative embodiment of a stent graft with a scalloped fenestration and an apertured fenestration suitable for use with a deployment device according to the invention; FIG. 20 shows a perspective view of one embodiment of stent graft mounted onto a deployment device according to the present invention; FIG. 21 shows the other side of the stent graft mounted onto a deployment device shown in FIG. 18 ; and FIG. 22 shows a general view of an alternative embodiment of deployment device according to the invention. DETAILED DESCRIPTION FIG. 1 shows a general view of a deployment device according to one embodiment of the invention and FIG. 2 shows a longitudinal cut-away view of the embodiment shown in FIG. 1 but rotated through 90 degrees on a longitudinal axis. In FIGS. 1 and 2 , it will be seen that the deployment device 1 generally consists of a guide wire catheter 2 which extends the full length of the device from a Luer lock connector 3 for a syringe at the far distal end of the device to and through a nose cone dilator 4 at the proximal end. The nose cone dilator 4 is fixed to the guide wire catheter 1 and moves with it. To lock the guide wire catheter with respect to the deployment device in general a pin vice 5 is provided. Trigger wire release mechanisms generally shown as 6 on a fixed handle 10 includes three trigger wire release mechanisms as will be discussed below. The trigger wire release mechanisms 6 slide on a portion of the fixed handle 10 and hence until such time as they are activated the trigger wire mechanisms 6 which are fixed by thumbscrews 11 remain fixed with respect to is the fixed portion of the fixed handle 10 . The trigger wire release mechanisms generally shown as 6 includes three trigger wire mechanisms 7 , 8 and 9 for three different stages of release of the stent graft from the deployment device. The three stages of release generally comprise: (1) release of the distal end of the stent graft; (2) release of diameter reducing ties; and (3) release of the proximal retention arrangements. The trigger wire release mechanism 9 has a trigger wire 48 (see FIG. 3A ) which extends to the capsule 21 and engages one of the loops of the exposed stent 29 . When the thumb screw 11 on the retention mechanism 9 is removed, the trigger wire mechanism 9 and trigger wire 48 can be removed and the capsule 21 can be removed from the exposed stent. The trigger wire release mechanism 8 extends a trigger wire 45 (see FIG. 3A ) to diameter reducing ties 43 on the stent graft. When the thumb screw 11 on the trigger wire mechanism 8 is removed, the trigger wire mechanism 8 and trigger wire 45 can be completely removed from the deployment device which releases the diameter reducing ties 43 . The trigger wire mechanism 7 has three trigger wires 76 (see FIG. 7 ) connected to it and when this trigger wire release mechanism 7 and trigger wires 76 are removed the proximal retention fastenings 90 , 91 and 92 (see FIG. 12 ) can be released to release the proximal end of the stent graft as is discussed in relation to FIGS. 7 , 8 and 12 to 14 . Immediately proximal of the trigger wire release mechanisms 6 on the fixed handle 10 is a sliding handle mechanism generally shown as 15 . The sliding handle mechanism 15 generally includes a fixed handle extension 16 and a sliding portion 17 the sliding portion 17 slides over the fixed handle extension 16 . A thumbscrew 18 fixes the sliding portion with respect to the fixed portion. The fixed handle portion 16 is affixed to the trigger wire mechanism handle 10 by a screw threaded nut 24 . More detail of the sliding and fixed handle mechanisms is shown in FIGS. 5 and 6 . The sliding portion of the handle 17 is fixed to the deployment catheter 19 by a mounting nut 20 . The deployment catheter 19 extends through to a capsule 21 at the proximal end of the deployment catheter 19 . Over and around the deployment catheter 19 is a sheath manipulator 22 and a sheath 23 which slides with respect to the deployment catheter 19 and in the ready to deploy situation extends forward to the nose cone dilator 4 to cover the stent graft 26 . The sheath 23 is preferably a highly flexible sheath. In the ready to deploy condition as shown in FIGS. 1 and 2 the sheath 23 assists in retaining the stent graft 26 , which includes self-expanding stents 26 , in a compressed condition. The proximal covered stent 27 is retained at proximal end 28 by a retention mechanism as will be discussed in detail with reference to FIGS. 7 , 8 and 12 to 16 and the distal exposed stent 29 on the stent graft 26 is retained within the capsule 21 on the deployment catheter 19 and by the distal retention mechanism as will be discussed in relation to FIG. 9 . An indwelling catheter 50 extends from the distal end of the deployment device along a groove 51 in the fixed handle 10 and under the trigger wire release mechanisms 7 , 8 and 9 . As can be seen particularly in FIG. 2 the indwelling catheter 50 then extends through an aperture 55 into the lumen between the guide wire catheter 2 and the fixed handle 10 to extend through the sliding handle mechanism as discussed below and then extends through the lumen between the guide wire catheter 2 and the deployment catheter to a further aperture 57 just distal of the capsule 21 . The indwelling catheter 50 then exits the deployment catheter 19 , passes over the capsule 21 and enters the fenestration 59 in the stent graft 26 and extends proximally through the lumen of the stent graft 26 to exit at the proximal end 28 and extend along the nose cone dilator 4 in a longitudinal groove 61 in the nose cone dilator 4 . The indwelling catheter 50 has a auxiliary guide wire 53 extending through it. This auxiliary guide wire 53 can be extended through the indwelling catheter to be snared to enable trans-brachial access for placement of branch stents through the fenestrations in the stent graft. FIG. 3 shows a detailed view of a portion of the deployment device shown in FIGS. 1 and 2 after a first stage of deployment and with a fenestrated stent graft retained thereon and FIG. 3A shows the same view as FIG. 3 except that it shows the other side of the stent graft and deployment device. In FIGS. 3 and 3A the stents on the stent graft are not shown for clarity. In FIGS. 3 and 3A the sheath 23 has been withdrawn distally to expose the stent graft 26 and the capsule 21 . The stent graft 26 is retained on the deployment device between the nose cone dilator 4 and the deployment catheter 19 . The proximal end 28 of the stent graft 26 is retained onto the deployment device distally of the nose cone dilator 4 by a retention arrangement as discussed below. The distal exposed stent 29 is retained in the capsule 21 and is locked in place using a trigger wire 48 as will be discussed below. The indwelling catheter 50 exits the deployment catheter 19 through aperture 57 , passes over the capsule 21 and enters the fenestration 59 in the stent graft 26 and extends proximally through the lumen of the stent graft 26 to exit at the proximal end 28 and extend along the nose cone dilator 4 in a longitudinal groove 61 . The other side of the stent graft 26 as shown in FIG. 3A has a number of diameter reducing ties 43 retained by a release mechanism as will be discussed below. FIG. 4 shows part of the deployment device as shown in FIG. 1 with an alternative stent graft retained thereon with a scalloped fenestration 66 and an apertured fenestration 67 . In FIG. 4 the stents on the stent graft are not shown for clarity. In FIG. 4 the sheath 23 has been withdrawn to expose the stent graft 26 and the capsule 21 . In this case there are two indwelling catheters 63 and 65 with the indwelling catheter 63 extending through scalloped fenestration 66 and the indwelling catheter 65 extending through the apertured fenestration 67 . The two indwelling catheters 63 and 65 extend forward to the nose cone dilator 4 and are received in grooves 68 and 69 respectively in the nose cone dilator 4 . Now looking more closely at FIGS. 5 and 6 the detailed construction of a particular embodiment of a sliding handle mechanism according to this invention is shown. FIG. 5 shows the sliding handle mechanism in the ready to deploy condition and FIG. 6 shows the mechanism when the deployment catheter and hence the capsule has been withdrawn by moving the sliding handle with respect to the fixed handle. The retraction of the capsule releases the distally extending exposed stent 29 on the stent graft 26 (see FIG. 2 ). The fixed handle extension 16 is joined to the trigger wire mechanism handle 10 by screw threaded nut 24 . The sliding handle 17 is fixed to the deployment catheter 19 by screw threaded fixing nut 20 so that the deployment catheter moves along with the sliding handle 17 . The sliding handle 17 fits over the fixed handle extension 16 and in the ready to deploy situation is fixed in relation to the fixed handle by locking thumbscrew 18 which engages into a recess 30 in the fixed handle extension 16 . On the opposite side of the fixed handle extension 16 is a longitudinal track 31 into which a plunger pin 32 spring loaded by means of spring 33 is engaged. At the distal end of the track 31 is a recess 34 . A guide tube 35 is fixed into the proximal end of the sliding handle 17 at 36 and extends back to engage into a central lumen in the fixed handle extension 16 but able to move in the central lumen. An O ring 37 seals between the fixed handle extension 16 and guide tube 35 . This provides a hemostatic seal for the sliding handle mechanism. The trigger wire 38 which is fixed to the trigger wire releasing mechanism 8 by means of screw 39 passes through the annular recess 42 between the fixed handle extension 16 and the guide wire catheter 2 and then more proximally in the annular recess 44 between the guide wire catheter 2 and the guide tube 35 and forward to extend through the annular recess 46 between the guide wire catheter 2 and the deployment catheter 19 and continues forward to the proximal retaining arrangement. Similarly the distal trigger wire (not shown in FIGS. 5 and 6 ) extends to the distal retaining arrangement and the diameter reducing release wire (not shown in FIGS. 5 and 6 ) extends to the diameter reducing ties. The indwelling catheter 50 extends from the distal end of the deployment device along the groove 51 in the fixed handle 10 and under the trigger wire release mechanism 8 . The indwelling catheter 50 extends through the aperture 55 into the lumen 42 between the guide wire catheter 2 and the fixed handle 10 to extend through the sliding handle mechanism. A further hemostatic seal 70 is provided where the guide wire catheter 1 enters the trigger wire mechanism handle 10 and the trigger wires 38 and the indwelling catheter 50 pass through the hemostatic seal 40 to ensure a good hemostatic seal. As can be seen in FIG. 6 the locking thumbscrew 18 has been removed and discarded and the sliding handle 17 has been moved onto the fixed handle 16 and the plunger pin 32 has slid back along the track 31 to engage into the recess 34 . At this stage the sliding handle cannot be moved forward again. As the trigger wire release mechanisms 7 , 8 and 9 are on the trigger wire mechanism handle 10 which is fixed with respect to the fixed handle 16 then the proximal trigger wire 38 is not moved when the deployment catheter 19 and the sliding handle 17 is moved so that it remains in position and does not prematurely disengage. In FIGS. 7 and 8 a proximal part of the stent graft deployment device is shown and includes the guide wire catheter 2 which extends the length of the deployment device and at the proximal end of the guide wire catheter 2 is the nose cone dilator 4 . Extending back from the nose cone dilator 4 and surrounding the guide wire catheter 2 is a trigger wire guide 72 . The trigger wire guide 72 is coaxial with the guide wire catheter 2 and defines a lumen 74 between them through which, in use, pass trigger wires 76 . Just distal of the nose cone dilator 4 there are apertures 78 in the trigger wire guide 72 extending into the lumen 74 and out of which apertures 78 extend the trigger wires 76 in a loop 80 so that it can engage the zig zag stents of a stent graft (see FIG. 13 ) or sutures can be engaged around the loops 80 and into a stent graft (see FIG. 12 ). The trigger wires 76 continue along the lumen 74 to terminate within the region of the nose cone dilator 4 . When it is desired to release the proximal end of the stent graft the trigger wires 76 are pulled out. FIG. 8 shows a cross sectional view along the line 8 B 8 =in FIG. 7 . It will be noted that the trigger wires 76 extend in the lumen 74 between the guide wire catheter 2 and the trigger wire guide 72 . The groove 61 in the nose cone 4 to receive the indwelling catheter 50 (see FIG. 3 ) can be seen in this drawing. FIG. 9 shows a detailed view of one embodiment of distal retention of a stent graft onto the deployment device of FIG. 1 . In this view it will be noted that the stent graft 26 has a tubular body 80 supported by stents 25 and having a distally extending exposed stent 29 . The distally extending exposed stent 29 is received in a proximally opening capsule 21 at the proximal end of the deployment catheter 19 . A locking wire 48 extends from the trigger wire release mechanism 6 (see FIG. 1 ) and engages a strut 29 a of the exposed stent 29 before exiting through an aperture 49 in the capsule 21 and being passed into the lumen of the stent graft 26 . A diameter reducing tie release wire 40 passes through the lumen between the guide wire catheter 2 and the deployment catheter 19 and through the capsule 21 and extends to the stent graft 26 where it is stitched in and out of the graft material at intervals, such as at 47 , longitudinally along the graft as is shown in FIG. 3A and as is discussed below in relation to FIG. 21 to engage the diameter reducing ties. The indwelling catheter 50 exits the deployment catheter 19 through aperture 57 in the deployment catheter and passes through scalloped fenestration 66 into the lumen of the stent graft 26 forward to the nose cone dilator as is discussed in relation to FIG. 3 . The capsule 21 is smaller in diameter than the deployment catheter 19 and is mounted off centre from the deployment catheter 19 so that sufficient space is provided beside the capsule on the side that the aperture 57 is in the deployment catheter 19 so that the indwelling catheter 50 can pass beside the capsule when the sheath (not shown) extends over the capsule 21 . FIGS. 10 and 11 show an arrangement of a stent graft including a fenestration of the type suitable for the present invention. The stent graft 100 comprises a tubular body 102 of biocompatible graft material with a lumen 104 therethrough. The stent graft 100 has a distal end 106 and a proximal end 105 . The proximal end 105 has barbs 107 to assist with retention when the stent graft 100 is deployed into the thoracic aorta, for instance. The distal end 106 of the stent graft has distally extending exposed stent 108 and within the tubular body 102 there are proximal and distal internal stents 110 and several external stents 112 intermediate the proximal and distal ends. A fenestration 114 is provided towards the distal end 106 of the stent graft 100 . In this embodiment the fenestration 114 is in the form of an aperture. Radiopaque or MRI opaque markers 116 are provided each side of the fenestration to enable visualisation of the fenestration to an accurate position with respect to a branch vessel. A retention arrangement to hold the proximal end of the stent graft 26 onto the deployment device in this embodiment is a multiple retention system with multiple fastenings and is shown in detail in FIG. 12 . At three points around the periphery of the stent graft 26 , fastenings 90 , 91 and 92 respectively pull the material of the stent graft to fasten onto trigger wires 76 . The trigger wires 76 extend through a lumen 74 of the trigger wire guide 72 which fits around guide wire catheter 2 as discussed in relation to FIGS. 7 and 8 back to the trigger wire release mechanism generally shown as 6 in FIGS. 1 and 2 . FIG. 13 shows a different retention arrangement in which the three points around the periphery of the stent graft 26 are directly engaged to the trigger wires 76 by the trigger wires 76 being passed through the material of the stent graft and more preferably around a bend of a stent of the stent graft as well as through the material of the stent graft. For clarity the stents are not shown in FIG. 13 . The trigger wires extend through a lumen 74 of the trigger wire guide 72 which fits around guide wire catheter 2 as discussed in relation to FIGS. 7 and 8 back to the trigger wire release mechanism generally shown as 6 in FIGS. 1 and 2 . FIG. 14 shows a general view of a proximal end of a stent graft 26 when retained by the mechanism as discussed above. It will be seen that there are three lobes 95 of graft material around the trigger wire guide 72 and guide wire catheter 2 . The indwelling catheter can easily pass through one of these to the groove 61 in the node cone dilator 4 (see FIG. 3 ). FIGS. 15 and 16 show an end on view of the proximal end of the stent graft 26 when mounted in an alternative manner onto a deployment device. FIG. 15 shows detail of the stent graft tubular body 26 constricted at three places by ties 90 a , 91 a and 92 a . As shown in FIG. 16 when the tie 91 a is released by removing the trigger wire 76 a , the end of the stent graft can open up to enable entry into the lumen of the stent graft. It will be noted that the loop of suture thread 91 a remains on the end of the stent graft 26 . FIG. 17 shows an alternative arrangement of a stent graft of the type suitable for the present invention and including a scalloped fenestration. The stent graft 120 comprises a tubular body 122 of graft material with a lumen 124 therethrough. The distal end 126 of the stent graft has distally extending exposed stent 128 and within the tubular body 122 there are proximal and distal internal stents 130 and three external stents 132 intermediate the proximal distal ends. A fenestration 134 is provided at the distal end 126 of the stent graft 100 . In this embodiment the fenestration 134 is in the form of a scallop or cut out extending from the distal end 126 of the stent graft 120 . The fenestration 134 is aligned with the struts 136 of the distal, internal, self expanding, zig zag stent 130 so that the sides of the fenestration 134 can be stitched by stitching 138 to the struts 136 along at least part of their length. FIG. 18 shows an alternative arrangement of scalloped fenestration on a stent graft. In this embodiment the scallop 140 is at the distal end of the tubular body 142 and the struts 144 and 145 of the distal self expanding stent either side of the scallop are shaped to give a more arch-like shape to the aperture. The edge of the scalloped fenestration 140 is stitched as at 146 to the strut to ensure that the scalloped fenestration 140 opens when the stent graft is released upon deployment. FIG. 19 shows an alternative arrangement of a stent graft of the type suitable for the present invention including both a fenestration and a scalloped fenestration. The stent graft 150 comprises a tubular body 152 of graft material with a lumen 154 therethrough. The distal end 156 of the stent graft 150 has distally extending exposed stent 158 and within the tubular body 152 there are proximal and distal internal stents 160 and at least one external stent 162 intermediate the proximal distal ends. A fenestration 164 is provided towards the distal end 156 of the stent graft 150 . In this embodiment the fenestration 164 is in the form of an aperture. A scalloped fenestration 166 is also provided towards the distal end 156 of the stent graft 150 . This fenestration 166 is in the form of a scallop or cut out extending from the distal end 156 of the stent graft 68 . The fenestration 82 is aligned with the struts of the distal, internal, self expanding, zig zag stent 160 so that the sides of the fenestration 90 can be stitched by stitching to the struts along at least part of their length. FIGS. 20 and 21 show two views of a stent graft mounted onto a delivery device according to an embodiment of the present invention and in particular in FIG. 21 showing the side of the stent graft upon which are the diameter reducing ties. The part of the delivery device 170 shown includes part of a nose cone dilator 172 and a guide wire catheter 174 with a guide wire lumen 175 therethrough. A proximal fastening for a stent graft 176 of the type shown in FIG. 13 is used which gives a clover leaf type pattern at the proximal end 177 of the stent graft 176 such as that shown in FIG. 15 . At the distal end of the stent graft 176 a capsule 180 is mounted in an off set manner on a deployment catheter 182 . The capsule 180 receives a distally extending exposed stent 184 which is fastened to the stent graft 176 . The stent graft 176 includes internal stents at each end and external stents 185 intermediate the ends. As can be seen in FIG. 20 an indwelling catheter 188 extends from an aperture 190 in the deployment catheter 182 and over the capsule 180 and into a fenestration 192 in the stent graft 176 . The indwelling catheter 188 extends through the lumen of the stent graft 176 and out of the proximal end 177 thereof and to the nose cone dilator 172 . A longitudinal groove 194 in the nose cone dilator 172 receives the indwelling catheter 188 . An anchor trigger wire 200 extends along the lumen (not shown) of the deployment catheter 182 and engages a bend of the exposed stent 184 within the capsule 182 and exits the capsule 182 through aperture 201 and then extends along the outside of the capsule and is inserted into the graft material of the stent graft 176 . The other side of the stent graft 176 is shown in FIG. 21 . On this side the diameter reducing ties 196 are provided to draw together some of the struts of the internal and external stents 185 so that the circumference and hence the diameter of the stent graft can be reduced to enable maneuverability after partial release of the stent graft after withdrawal of the sheath (not shown). The diameter reducing ties are placed on the side of the stent graft opposite to the fenestration or fenestrations. The diameter reducing ties are fastened to a release wire 198 which extends out of the capsule 180 and is stitched in and out of the graft material. As the diameter reducing ties 196 are tightened the struts of the stents 185 are drawn together and the graft material is corrugated between them. FIG. 22 shows a general view of an alternative embodiment of deployment device according to the invention. In this drawing the same reference numeral will be used for corresponding components to those of FIG. 1 . In FIG. 22 it will be seen that the deployment device 200 generally consists of a guide wire catheter 2 which extends the full length of the device from a Luer lock connector 3 for a syringe at the far distal end of the device to and through a nose cone dilator 4 at the proximal end. The nose cone dilator 4 is fixed to the guide wire catheter 2 and moves with it. To lock the guide wire catheter 2 with respect to the deployment device in general a pin vice 4 is provided. The trigger wire release mechanism generally shown as 6 on a fixed handle 10 includes four trigger wire release mechanisms as will be discussed below. The trigger wire release mechanisms 6 slide on a portion of the fixed handle 10 and hence until such time as they are activated the trigger wire mechanisms 6 which are fixed by thumbscrews 11 remain fixed with respect to the fixed portion of the fixed handle 10 . Immediately proximal of the trigger wire release mechanisms 6 is the sliding handle mechanism generally shown as 15 . The sliding handle mechanism 15 generally includes a fixed handle extension 16 and a sliding portion 17 the sliding portion 17 slides over the fixed handle extension 16 . A thumbscrew 18 fixes the sliding portion with respect to the fixed portion. The fixed handle portion 16 is affixed to the trigger wire mechanism handle 10 by a screw threaded nut 24 . The sliding portion of the handle 17 is fixed to the deployment catheter 19 by a mounting nut 20 . The deployment catheter 19 extends through to a capsule 21 at the proximal end of the deployment catheter 19 . Over the deployment catheter 19 is a sheath manipulator 22 and a sheath 23 which slides with respect to the deployment catheter 19 and in the ready to deploy situation extends forward to the nose cone 3 to cover the stent graft 26 . In the ready to deploy condition shown in FIG. 22 the sheath 23 assists in retaining the stent graft 26 which includes self-expanding stents 25 in a compressed condition. The proximal covered stent 27 is retained at 28 by a retention mechanism as will be discussed later and the distal exposed stent 29 on the stent graft 26 is retained within the capsule 21 on the deployment catheter 19 and by a distal retention mechanism. For this release mechanism the handle include four trigger wire release grips 7 , 8 9 and 12 . The first grip 12 is fastened to the trigger wire 76 a (see FIG. 15 ) and by removal of the thumb screw 11 on release trigger wire release mechanism 12 , the trigger wire 76 a (see FIG. 15 ) can be completely withdrawn from the deployment device which releases the fastening 91 a so that the retention of the proximal end of the stent graft changes from that shown in FIG. 15 to that shown in FIG. 16 . The trigger wire release mechanism 9 has a trigger wire which extends to the capsule at the proximal end of the deployment catheter and engages one of the loops of an exposed stent 29 of the stent graft 26 . When the thumb screw 11 on the retention mechanism 9 is removed, that trigger wire can be removed and the capsule can be removed from the exposed stent. The trigger wire release mechanism 8 extends a trigger wire 45 to diameter reducing ties 43 on the stent graft 26 (see FIG. 3A ). When the thumb screw 11 on the trigger wire mechanism 8 is removed, the trigger mechanism 8 can be completely removed from the deployment device which releases the diameter reducing ties as discussed in detail in relation to FIG. 21 . The trigger wire mechanism 7 has two trigger wires 76 connected to it and when this trigger wire release mechanism is removed the remaining proximal retention fastenings 90 a and 92 a can be released to release the proximal end of the stent graft as is discussed in relation to FIGS. 15 and 16 . As can be seen in FIG. 16 the proximal end of the stent graft is partially open and a guide wire can be introduced through the larger lobe 97 via a cranial or brachial entry into the aorta so that it can extend into the lumen within the stent graft 26 and by careful manipulation extend out through a fenestration in the stent graft. To assist with placement of the guide wire the rotational, longitudinal position of the stent graft 26 can still be adjusted because the diameter reducing ties prevent the stent graft from fully expanding against the walls of the vessel. An indwelling catheter 50 extends from the distal end of the deployment device along a groove 51 in the fixed handle 10 and under the trigger wire release mechanisms 7 , 8 , 9 and 12 . The indwelling catheter 50 has a auxiliary guide wire 53 extending through it. The indwelling catheter 50 and auxiliary guide wire 53 can be extended out of the stent graft after the stent graft has been partially released at its proximal end as discussed in relation to FIGS. 15 and 16 . The auxiliary guide wire 53 can then be extended through the indwelling catheter to be snared to enable trans-brachial access for placement of branch stents through the fenestrations in the stent graft. It will be seen that by this invention there is provided a deployment device which ensures good control of the stent graft during deployment is possible by the use of an indwelling catheter and separate release mechanisms. In particular for fenestrated stent grafts a partial retention removal stage will assist with ensuring that access to the lumen of the stent graft to enable placement of a catheter through the stent graft and fenestration into a branch vessel is possible. Throughout this specification various indications have been given as to the scope of the invention but the invention not limited to any one of these but may reside in two or more of these combined together. The examples are given for illustration only and not for limitation.

A stent graft introducer for intraluminal deployment of a stent graft ( 26 ), the introducer comprising a stent graft release mechanism ( 6 ) to allow partial release of the stent graft ( 26 ) when carried on the introducer, whereby control of the stent graft can be maintained while allowing access into the lumen of the stent graft from at least one end of the stent graft. The partial release can comprise partial release of one end of the stent graft.

[0001] This is a continuation of U.S. application Ser. No. 10/350,816, filed Jan. 24, 2003, which is incorporated herein by reference. U.S. application Ser. No. 10/350,816 claims the benefit of U.S. Provisional Application No. 60/389,078, filed Jun. 14, 2002, and of U.S. Provisional Application No. 60/351,949, filed Jan. 25, 2002. FIELD OF THE INVENTION [0002] The present invention relates to the field of cell and tissue culture. More specifically, the invention relates to methods and compositions for ex vivo propagation of cells capable of forming cartilaginous tissue intended for treatment or repair of cartilage defects. BACKGROUND OF THE INVENTION [0003] Articular cartilage is composed of chondrocytes encased within the complex extracellular matrix produced by these cells. The unique biochemical composition of this matrix provides for the smooth, nearly frictionless motion of articulating surfaces of the knee joint. With age, tensile properties of human articular cartilage change as a result of biochemical changes. After the third decade of life, the tensile strength of articular cartilage decreases markedly. Damage of cartilage produced by trauma or disease, e.g., rheumatoid and osteoarthritis, can lead to serious physical debilitation. [0004] The inability of cartilage to repair itself has led to the development of several surgical strategies to alleviate clinical symptoms associated with cartilage damage. More than 500,000 arthroplastic procedures and joint replacements are performed annually in the United States alone. Autologous chondrocyte implantation is a procedure that has been approved for treatment of articular cartilage defects. The procedure involves harvesting a piece of cartilage from a non-weight bearing part of the femoral condyle and propagating the isolated chondrocytes ex vivo for subsequent implantation back into the same patient (Brittberg et al. (1994) New England J. of Medicine, 331: 889-895). [0005] Articular chondrocytes express articular cartilage-specific extracellular matrix components. Once articular chondrocytes are harvested and separated from the tissue by enzymatic digestion, they can be cultured in monolayers for proliferative expansion. However, during tissue culture, these cells become phenotypically unstable, adopt a fibroblastic morphology, and then cease to produce type II collagen and proteoglycans characteristic of hyaline-like articular cartilage. Such “dedifferentiated” cells proliferate rapidly and produce type I collagen, which is characteristic of fibrous tissue. Nevertheless, when placed in an appropriate environment such as suspension culture medium in vitro (Aulthouse et al. (1989) In Vitro Cell. & Devel. Biology, 25: 659-668) or in the environment of a cartilage defect in vivo (Shortkroff et al. (1996) Biomaterials, 17: 147-154), the cells redifferentiate, i.e., express articular cartilage-specific matrix molecules again. The reversibility of dedifferentiation is key to the successful repair of articular cartilage using cultured autologous chondrocytes. [0006] Human chondrocytes are typically cultured in Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% (v/v) fetal bovine serum (FBS) (Aulthouse et al. (1989) In Vitro Cell. & Devel. Biology, 25: 659-668; Bonaventure et al. (1994) Exp. Cell Res., 212: 97-104). However, even though serum is widely used for mammalian cell culture, there are several problems associated with its use (Freshney (1994) Serum-free media. In Culture of Animal Cells, John Wiley & Sons, New York, 91-99): 1) serum contains many unidentified or non-quantified components and therefore is not “defined;” 2) the composition of serum varies from lot to lot, making standardization difficult for experimentation or other uses of cell culture; 3) many of the serum components affect cell attachment, proliferation, and differentiation making it difficult to control these parameters; 4) some components of serum are inhibitory to the proliferation of specific cell types and to some degree may counteract its proliferative effect, resulting in sub-optimal growth; and 5) serum may contain viruses and other pathogens which may affect the outcome of experiments or provide a potential health hazard if the cultured cells are intended for implantation in humans. [0007] Thus, the use of defined serum-free media is particularly advantageous in the ex vivo expansion of chondrocytes for treatment of cartilage defects. However, such defined serum-free media must be sufficient for attachment of adult human articular chondrocytes seeded at low density, sustain proliferation until confluent cultures are attained, and maintain the capacity of chondrocytes to re-express the articular cartilage phenotype. [0008] There has been some effort to develop biochemically defined media (DM) for cell culture. DM generally includes nutrients, growth factors, hormones, attachment factors, and lipids. The precise composition must be tailored for the specific cell type for which the medium is designed. Successful growth of some cell types, including fibroblasts, keratinocytes, and epithelial cells has been achieved in various DM (reviewed by Freshney, 1994). However, attachment and proliferation of cells in the known media are often not optimal. [0009] Additionally, the amounts of starting cell material available for autologous chondrocyte implantation are generally limited. Therefore, it is desirable to seed articular chondrocytes at a minimal subconfluent density. Attempts to culture articular chondrocytes at subconfluent densities in DM have been only partially successful. Although DM that can sustain the proliferative capacity of the chondrocytes seeded at low density have been developed, the use of these media still requires serum for the initial attachment of cells to the tissue culture vessel after seeding (Adolphe et al. (1984) Exp. Cell Res., 155: 527-536, and United States Patent No. 6,150,163). [0010] A need exists to optimize, standardize, and control conditions for attachment, proliferation and maintenance of redifferentiation-capable chondrocytes for use in medical applications, especially, in humans. SUMMARY OF THE INVENTION [0011] It is an object of the invention to provide safe, effective, and inexpensive culture medium compositions and methods for culturing articular chondrocytes. [0012] It is another object of the invention to provide a method for culturing articular chondrocytes which does not involve the use of serum. [0013] It is yet another object of the invention to provide a simple method for culturing articular chondrocytes in a single defined cell culture medium. [0014] It is yet another object of the invention to provide a method for culturing articular chondrocytes under serum-free conditions, wherein chondrocytes are seeded at low subconfluent densities. [0015] Still another object of the invention is to provide a method for ex vivo expansion of articular chondrocytes, in which the cells retain their redifferentiation capacity. [0016] The invention provides a method for culturing human articular chondrocytes and compositions of chemically defined culture media. The DM of the invention avoid the use of serum at any stage of chondrocyte culture and enhance cell attachment and proliferation under serum-free conditions while maintaining the capacity of chondrocytes to re-express cartilage-specific phenotype. [0017] One aspect of the invention provides defined cell culture media that are sufficient for the initial attachment of cells to a culture substratum, thereby eliminating a need for a serum-containing medium in the initial stage of cell culture. Another aspect of the invention provides defined serum-free cell culture media that promote proliferation of chondrocytes without use of serum at any stage during cell culture. Yet another aspect of the invention provides cell culture media that may be used to prime chondrocytes prior to implantation into a subject or included as a redifferentiation-sustaining medium to chondrocytes embedded in a matrix intended for implantation into cartilage defects. [0018] In certain embodiments, the DM of the invention comprises a basal medium. In one embodiment, the basal medium is prepared using commercially available culture media such as DMEM, RPMI-1640, and Ham's F-12. In one embodiment, DMEM, RPMI-1640, and Ham's F-12 are mixed at a 1:1:1 ratio and combined with growth supplements to produce the basal medium defined in Table 3 (referred to hereinafter as cDRF). In addition to a basal medium, the DM of the invention comprises at least two of the supplements selected from the group consisting of: platelet-derived growth factor (PDGF), and one or more lipid components selected from the group consisting of stearic acid, myristic acid, oleic acid, linoleic acid, palmitic acid, palmitoleic acid, arachidonic acid, linolenic acid, cholesterol, and alpha-tocopherol acetate. In a particular embodiment, DM comprises PDGF and at least one lipid component. In related embodiments, DM comprises PDGF and at least two, four, six, eight, or all of the lipid components set forth in Table 4. In a further embodiment, the PDGF is PDGF-BB. In certain embodiments, the concentration of PDGF is chosen from 0.1-1 ng/ml, 1-5 ng/ml, 5-10 ng/ml, 10 ng/ml, 10-15 ng/ml, 15-50 ng/ml, and 50-100 ng/ml. In certain other embodiments, the concentration (v/v) of lipid components is chosen from 0.05-0.1%, 0.1-0.5%, 0.5%, 0.5-1%, 1-2%, and 2-5%. [0019] 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. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. [0020] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. [0021] The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE FIGURES [0022] FIG. 1 is a diagram of growth index for human articular chondrocytes propagated ex vivo for four passages in DMEM/10% FBS or cDRF (defined in Table 3), cDRF supplemented with 10 ng/ml PDGF, and cDRF supplemented with 10 ng/ml PDGF and 5 μl/ml of the chemically defined lipid mixture (CDLM) set forth in Table 4. [0023] FIG. 2 illustrates cell yields for human articular chondrocytes plated at various seeding densities and propagated ex vivo for four passages in DMEM/10% FBS or in the defined serum-free media as follows: cDRF; cDRF supplemented with 10 ng/ml PDGF; and cDRF supplemented with 10 ng/ml PDGF and 5 μl/ml CDLM. [0024] FIGS. 3A and 3B depict results of a TaqMan analysis of genes expressed by chondrocytes expanded in DMEM/10% FBS or in cDRF supplemented with 10 ng/ml PDGF and 5 μl/ml CDLM. DETAILED DESCRIPTION OF THE INVENTION [0025] This invention provides a method for culturing chondrocytes in a defined serum-free media and is based, at least in part, on the discovery that the basal medium referred to as cDRF, as described below, when supplemented with PDGF and at least on of the lipids set forth in Table 4, is sufficient for attachment, proliferation and maintenance of redifferentiation-capable chondrocytes in culture and can substitute for a serum-containing medium in all stages of cell culture. [0000] Preparation of Basal Medium (cDRF) [0026] The first step in preparing defined, serum media (DM) of the invention is to prepare a basal medium. In a particular embodiment, the basal medium defined in Table 3 (cDRF), is prepared from commercially available starting components as described below. cDRF is a modification of the DM developed by Adolphe et al. (1994) and by McPherson et al. (U.S. Pat. No. 6,150,163). [0027] The three starting components of cDRF are DMEM, RPMI-1640, and Ham's F12 (Gibco BRL, Grand Island, N.Y.). The precise composition of each of these starting components is set forth in Table 1. The starting components are combined at a 1:1:1 ratio. The resulting medium (defined in Table 2 and referred to as DRF) is then supplemented with ITS (10 μg/ml insulin, 5.5 μg/ml transferrin, 7 ng/ml selenium, and, optionally, 2.0 μg/ml ethanolamine), human fibronectin (Collaborative Biomedical Products, Bedford, Mass.), human serum albumin (HSA), linoleic acid, human basic fetal growth factor (bFGF) (R&D Systems, Minneapolis, Minn.), gentamycin (BioWhittaker, Walkersville, Md.), and hydrocortisone (Sigma, St. Louis, Mo.) to create cDRF. Freshly prepared incomplete cDRF (cDRF without bFGF, fibronectin, linoleic acid, and HSA) can be stored in the dark up to 2 weeks at 2-8° C. bFGF, fibronectin, and HSA supplemented with linoleic acid are diluted into the medium to create cDRF on the day of use for cell culture. HSA utilized in the media of the invention is either purified from human plasma (Grifols® HSA, SeraCare, Oceanside, Calif.) or recombinant (New Century Pharmaceuticals, Huntsville, Ala.). All materials are reconstituted, diluted, and stored as per suppliers' recommendations. [0028] The term “basal medium” is used interchangeably with “defined basal medium” and refers to any medium that comprises all essential components of cDRF listed in Table 3. A component or a subset of components listed in Table 3 is non-essential if, when its concentration is reduced, or the component is eliminated, the properties of the medium related to chondrocyte attachment, proliferation, and redifferentiation, remain substantially the same. The stated concentrations of individual components may be adjusted for specific cell culture conditions. Such adjustments can easily be made by a person skilled in the art using routine techniques. It will also be understood that additional components may be added to the medium if such components are desirable and do not negatively impact on chondrocytes attachment, proliferation, and redifferentiation. Such components include growth factors, lipids, serum proteins, vitamins, minerals, carbohydrates. For example, it may be advantageous to supplement the medium with growth factors or hormones that promote chondrocyte redifferentiation such as TGF-β (TGF-β1, -β2, -β3), IGF, and insulin, as described in U.S. Pat. No. 6,150,163. Such growth factors and hormones are commercially available. Additional examples of supplements include, but are not limited to, bone morphogeneteic proteins (BMP), of which there are at least 15 structurally and functionally related proteins. BMP have been shown to be involved in the growth, differentiation, chemotaxis, and apoptosis of various cell types. Recombinant BMP-4 and BMP-6, for example, can be purchased from R&D Systems (Minneapolis, Minn.; catalog #314-BP and 507-BP, respectively). The concentration of various supplements in DM of the invention can be determined without undue experimentation. The concentration of BMP in DM of the invention is chosen from 0.01-0.1 ng/ml, 0.1-1 ng/ml, 1-10 ng/ml, 100 ng/ml, 10-50 ng/ml, 50-100 ng/ml, and 0.1-1 μg/ml. [0029] A skilled artisan will appreciate that DM of the invention have advantages in addition to avoiding the use of serum. Thus, it may be desirable to utilize DM of the invention in applications where the use of undefined components is acceptable. Consequently, DM of the invention may be supplemented with serum e.g., fetal calf serum, or other chemically undefined components such as, for example, animal or plant tissue extracts. In certain embodiments, the DM of the invention may be supplemented with 10% or less than 8%, 6%, 4%, 2%, or 1% of serum. [0030] A skilled artisan will also appreciate that equivalents of cDRF may be prepared from a variety of known media, e.g., Basal Medium Eagle medium (Eagle, Science, 122: 501, 1955), Minimum Essential medium (Dulbecco et al., Virology, 8: 396, 1959), Ham's medium (Ham, Exp. Cell Res., 29: 515,1963), L-15 medium (Leibvitz, Amer. J. Hyg., 78:173,1963), McCoy 5A medium (McCoy et al., Proc. Exp. Biol. Med., 100: 115,1959), RPMI medium (Moore et al., J. A. M. A., 199: 519,1967), Williams' medium (Williams, Exp. Cell Res., 69:106-112,1971), NCTC 135 medium (Evans et al., Exp. Cell Res., 36: 439,1968), Waymouth's medium MB752/1 (Waymouth, Nat. Cancer Inst., 22: 1003,1959), etc. These media may be used singularly or as mixtures in suitable proportions to prepare a basal medium equivalent to cDRF. Alternatively, cDRF or its equivalent can be prepared from individual chemicals or from other media and growth supplements. The invention is not limited to media of any particular TABLE 1 Compositions of Starting Media DMEM RPMI-1640 Ham's F-12 1× Liquid, 1× Liquid, 1× Liquid, mg/L mg/L mg/L Inorganic Salts CaCl 2 (anhyd.) 200.00 33.22 Ca(NO 3 ) 2 •4H 2 O 100.00 CuSO 4 •5H 2 O 0.0024 Fe(NO 3 ) 2 •9H 2 O 0.10 FeSO 4 •7H 2 O 0.83 KCl 400.00 400.00 223.60 MgSO 4 (anhyd.) 97.67 48.84 MgCl 2 (anhyd.) 57.22 NaCl 6400.00 6000.00 7599.00 NaHCO 3 3700.00 2000.00 1176.00 NaH 2 PO 4 •H 2 O 125.00 Na 2 HPO 4 (anhyd.) 800.00 142.00 ZnSO 4 •7H 2 O 0.86 Other Components D-Glucose 4500.00 2000.00 1802.00 Glutathione (reduced) 1.00 Hypoxanthine Na 4.77 Linoleic Acid 0.084 Lipoic Acid 0.21 Phenol Red 15.00 5.00 1.20 Putrescine•2HCl 0.161 Sodium Pyruvate 110.00 Thymidine 0.70 Amino Acids L-Alanine 8.90 L-Arginine 200.00 L-Arginine•HCl 84.00 211.00 L-Asparagine•H 2 O 15.01 L-Asparagine (free base) 50.00 L-Aspartic Acid 20.00 13.30 L-Cystine•2HCl 63.00 65.00 L-Cysteine•HCl•H 2 O 35.12 L-Glutamic Acid 20.00 14.70 L-Glutamine 584.00 300.00 146.00 Glycine 30.00 10.00 7.50 L-Histidine•HCl•H 2 O 42.00 21.00 L-Histidine (free base) 1.00 5.00 L-Hydroxyproline 20.00 L-Isoleucine 105.00 50.00 4.00 L-Leucine 105.00 50.00 13.10 L-Lysine•HCl 146.00 40.00 36.50 L-Methionine 30.00 15.00 4.50 L-Phenylalanine 66.00 15.00 5.00 L-Proline 20.00 34.50 L-Serine 42.00 30.00 10.50 L-Threonine 95.00 20.00 11.90 L-Tryptophan 16.00 5.00 2.00 L-Tyrosine•2Na•2H 2 O 104.00 29.00 7.81 L-Valine 94.00 20.00 11.70 Vitamins Biotin 0.20 0.0073 D-Ca pantothenate 4.00 0.25 0.50 Choline Chloride 4.00 3.00 14.00 Folic Acid 4.00 1.00 1.30 I-Inositol 7.20 35.00 18.00 Niacinamide 4.00 1.00 0.036 Para-aminobenzoic Acid 1.00 Pyridoxine HCl 1.00 0.06 Pyridoxal HCl 4.00 Riboflavin 0.40 0.20 0.037 Thiamine HCl 4.00 1.00 Vitamin B 12 0.005 1.40 [0031] TABLE 2 Composition of DRF 3× Liquid, mg/L Inorganic Salts CaCl 2 (anhyd.) 233.22 Ca(NO 3 ) 2 •4H 2 O 100.00 CuSO 4 •5H 2 O 0.0024 Fe(NO 3 ) 2 •9H 2 O 0.10 FeSO 4 •7H 2 O 0.83 KCl 1023.60 MgSO 4 (anhyd.) 146.51 MgCl 2 (anhyd.) 57.22 NaCl 19999.00 NaHCO 3 6876.00 NaH 2 PO 4 •H 2 O 125.00 Na 2 HPO 4 (anhyd.) 942.00 ZnSO 4 •H 2 O 0.86 Other Components D-Glucose 8302.00 Glutathione (reduced) 1.00 Hypoxanthine•Na 4.77 Linoleic Acid 0.084 Lipoic Acid 0.21 PhenolRed 21.20 Putrescine 2HCl 0.161 Sodium Pyruvate 110.00 Thymidin 0.70 Amino Acids L-Alanine 8.90 L-Arginine 200.00 L-Arginine•HCl 295.00 L-Asparagine•H 2 O 15.01 L-Asparagine (free base) 50.00 L-Aspartic Acid 33.30 L-Cystine•2HCl 128.00 L-Cysteine HCl•H 2 O 35.12 L-Glutamic Acid 34.70 L-Glutamine 1030.00 Glycine 47.50 L-Histidine•HCl•H 2 O 63.00 L-Histidine (free base) 15.00 L-Hydroxyproline 20.00 L-Isoleucine 159.00 L-Leucine 168.10 L-Lysine•HCl 222.50 L-Methionine 49.50 L-Phenylalanine 86.00 L-Proline 54.50 L-Serine 82.50 L-Threonine 126.90 L-Tryptophan 23.00 L-Tyrosine 2Na•2H 2 O 140.81 L-Valine 125.70 Vitamins Biotin 0.2073 D-Ca pantothenate 4.75 Choline Chloride 21.00 Folic Acid 6.30 i-Inositol 60.20 Niacinamide 5.036 Para-aminobenzoic Acid 1.00 Pyridoxine•HCl 1.06 Pyridoxal•HCl 4.00 Riboflavin 0.637 Thiamine•HCl 5.30 Vitamin B 12 1.405 [0032] TABLE 3 Composition of cDRF 1× Liquid Basal Components DRF 99% ITS 1% Supplements Linoleic Acid 5 μg/ml Gentamycin 100 μg/ml Hydrocortisone 40 ng/ml Fibronectin 5 μg/ml Basic FGF 10 ng/ml Human Serum Albumin 1 mg/ml consistency and encompasses the use of media ranging from liquid to semi-solid and includes solidified media and solid compositions suitable for reconstitution. Supplementation of Basal Medium [0033] Platelet-Derived Growth Factor (PDGF) [0034] PDGF is a major mitogenic factor present in serum but not in plasma. PDGF is a dimeric molecule consisting of two structurally related chains designated A and B. The dimeric isoforms PDGF-AA, AB and BB are differentially expressed in various cell types. In general, all PDGF isoforms are potent mitogens for connective tissue cells, including dermal fibroblasts, glial cells, arterial smooth muscle cells, and some epithelial and endothelial cell. [0035] Recombinantly produced PDGF is commercially available from various sources. Human recombinant PDGF-BB (hrPDGF-BB) used in the examples below was purchased from R&D Systems (Minneapolis, Minn.; catalog #220-BB) and reconstituted and handled according to the manufacturer's instructions. The E. coli expression of hrPDGF-BB and the DNA sequence encoding the 109 amino acid residue mature human PDGF-B chain protein (C-terminally processed from that ends with threonine residue 190 in the precursor sequence) is described by Johnson et al. ( EMBO J., 3: 921, 1984). The disulfide-linked homodimeric rhPDGF-BB consists of two 109 amino acid residue B chains and has molecular weight of about 25 kDa. The activity of PDGF is measured by its ability to stimulate 3 H-thymidine incorporation in quiescent NR6R-3T3 fibroblast as described by Raines et al. ( Methods in Enzymology 109: 749-773, 1985). The ED 50 for PDGF in this assay is typically 1.0-3 ng/ml. [0036] In certain embodiments, DM of the invention is cDRF supplemented with PDGF and BMP or one or more lipids selected from the group consisting of stearic acid, myristic acid, oleic acid, linoleic acid, palmitic acid, palmitoleic acid, arachidonic acid, linolenic acid, cholesterol, and alpha-tocopherol acetate. The concentration of PDGF is chosen from 0.1-1 ng/ml, 1-5 ng/ml, 5-10 ng/ml, 10 ng/ml, 10-15 ng/ml, 15-50 ng/ml, and 50-100 ng/ml. In certain embodiments, cDRF is supplemented with 1 to 25 ng/ml, more preferably, 5 to 15 ng/ml and, most preferably, 10 ng/ml of PDGF. In a particular embodiment, the PDGF is PDGF-BB. Alternatively, PDGF could be of another type, e.g., PDGF-AB, PDGF-BB, or a mix of any PDGF types. In related embodiments, the DM of the invention further comprises additional supplements as described below. [0000] Lipids [0037] Lipids are important as structural components as well as potential energy sources in living cells. In vitro, most cells can synthesize lipids from glucose and amino acids present in the culture medium. However, if extracellular lipid is available, lipid biosynthesis is inhibited and the cells utilize free fatty acids, lipid esters, and cholesterol in the medium. Serum is rich in lipids and has been the major source of extracellular lipid for cultured cells. Chemically undefined lipid preparations based on marine oils have been found to be effective in promoting growth of cells in serum free-media in several systems (Weiss et al. (1990) In Vitro 26: 30A; Gorfien et al. (1990) In Vitro 26: 37A; Fike et al. (1990) In Vitro 26: 54A). Thus, supplementation of serum-free media with various lipids to replace those normally supplied by serum may be desirable. [0038] Suitable lipids for use in the DM of this invention include stearic acid, myristic acid, oleic acid, linoleic acid, palmitic acid, palmitoleic acid, arachidonic acid, linolenic acid, cholesterol, and alpha-tocopherol acetate. In one embodiment, the basal medium is supplemented with the chemically defined lipid mixture (CDLM), shown in Table 4. CDLM is available from Gibco BRL (catalog #11905-031). As supplied by Gibco BRL, in addition to the lipid components, CDLM contains ethanol (100 g/L) and emulsifiers Pluronic F68® (100 g/L) and Tween 80® (2.2 g/L). [0039] In practicing the methods of the invention, the concentrations of individual lipid components of CDLM shown in Table 4 may be adjusted for specific cell culture conditions. Such adjustments can easily be made by a person skilled in the art using routine techniques. Furthermore, not all components of CDLM may be essential. A component or a subset of components is non-essential if, when its concentration is reduced, or the component is eliminated, the properties of the medium related to chondrocyte attachment, proliferation, and redifferentiation, remain substantially the same. [0040] In certain embodiments, the DM of the invention comprises at least one, two, four, six, eight, or all lipid components of CDLM. In one embodiment, the DM comprises PDGF and CDLM as defined in Table 4. In other nonlimiting illustrative embodiments, the DM comprises PDGF and lipid combinations as set forth in Table 5. TABLE 4 Composition of CDLM Lipid components mg/L DL-alpha-tocopherol acetate 70 Stearic acid 10 Myristic acid 10 Oleic acid 10 Linoleic acid 10 Palmitic acid 10 Palmitoleic acid 10 Arachidonic acid 2 Linolenic acid 10 Cholesterol 220 [0041] In certain embodiments, the concentration (v/v) of lipids in the culture medium is chosen from 0.05-0.1%, 0.1-0.5%, 0.5%, 0.5-1%, 1-2%, and 2-5%. In certain other embodiments, DM is additionally supplemented with 1 to 25 ng/ml, more preferably, 5 to 15 ng/ml, and, most preferably, 10 ng/ml of PDGF. In a particular embodiment, DM comprises approximately 0.5% (v/v) CDLM, and 10 ng/ml PDGF. [0042] The media can be used to seed, grow, and maintain chondrocytes capable of redifferentiation in culture without the use of serum. The stated ranges of concentrations of PDGF and lipids may need to be adjusted for specific cell culture conditions. Such adjustments can easily be made by a person skilled in art using routine techniques. TABLE 5 Illustrative Lipid Combinations 1 cholesterol 2 cholesterol, arachidonic acid 3 cholesterol, arachidonic acid, linoleic acid 4 cholesterol, arachidonic acid, linoleic acid, linolenic acid 5 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate 6 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid 7 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid 8 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid 9 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid 10 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid, palmitic acid 11 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 12 arachidonic acid, linoleic acid, linolenic acid, alpha- tocopherol acetate, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 13 arachidonic acid, linoleic acid, linolenic acid, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 14 arachidonic acid, linoleic acid, linolenic acid, stearic acid, myristic acid, oleic acid, palmitic acid 15 arachidonic acid, linoleic acid, linolenic acid, stearic acid, myristic acid, oleic acid 16 arachidonic acid, linoleic acid, linolenic acid, stearic acid, myristic acid 17 arachidonic acid, linoleic acid, linolenic acid, acetate, stearic acid 18 arachidonic acid, linoleic acid, linolenic acid, stearic acid 19 arachidonic acid, linoleic acid, linolenic acid 20 arachidonic acid, linoleic acid 21 arachidonic acid 22 cholesterol, linoleic acid 23 cholesterol, linoleic acid, linolenic acid 24 cholesterol, linoleic acid, linolenic acid, stearic acid 25 cholesterol, linoleic acid, linolenic acid, stearic acid, myristic acid 26 cholesterol, linoleic acid, linolenic acid, stearic acid, myristic acid, oleic acid 27 cholesterol, linoleic acid, linolenic acid, stearic acid, myristic acid, oleic acid, palmitic acid 28 cholesterol, linoleic acid, linolenic acid, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 29 cholesterol, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 30 linoleic acid 31 cholesterol, linoleic acid 32 cholesterol, arachidonic acid, linoleic acid 33 cholesterol, arachidonic acid, linoleic acid, linolenic acid 34 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate 35 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid 36 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid 37 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid 38 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid 39 cholesterol, arachidonic acid, linoleic acid, linolenic acid, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 40 linolenic acid 41 cholesterol, linolenic acid 42 cholesterol, alpha-tocopherol acetate, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 43 cholesterol, alpha-tocopherol acetate 44 cholesterol, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 45 stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 46 cholesterol, myristic acid, oleic acid, palmitic acid, palmitoleic acid 47 cholesterol, oleic acid, palmitic acid, palmitoleic acid 48 cholesterol, stearic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid 49 cholesterol, myristic acid, oleic acid, palmitic acid 50 cholesterol, arachidonic acid, linoleic acid, linolenic acid, palmitic acid, palmitoleic acid [0043] Chondrocytes and Other Suitable Cells [0044] The present invention is generally suitable for ex vivo proliferation of cells capable of producing cartilaginous tissue. Chondrocytes are cells found in various types of cartilage, e.g., hyaline cartilage, elastic cartilage, and fibrocartilage. Chondrocytes are mesenchymal cells that have a characteristic phenotype based primarily on the type of extracellular matrix they produce. Precursor cells produce type I collagen, but when they become committed to the chondrocyte lineage, they stop producing type I collagen and start synthesizing type II collagen, which constitutes a substantial portion of the extracellular matrix. In addition, committed chondrocytes produce proteoglycan aggregate, called aggrecan, which has glycosaminoglycans that are highly sulfated. [0045] Chondrocytes can be isolated from any mammal, including, without limitation, human, orangutan, monkey, chimpanzee, dog, cat, rat, rabbit, mouse, horse, cow, pig, elephant, etc. Chondrocytes used in the present invention can be isolated by any suitable method. Various starting materials and methods for chondrocyte isolation are well known in the art (Freshney (1987) Culture of Animal Cells: A Manual of Basic Techniques, 2d ed. A. R. Liss, Inc., New York, pp. 137-168; Klagsburn (1979) Methods Enzymol. 58: 560-564). By way of example, articular cartilage can be harvested from femoral condyles of human donors, and chondrocytes can be released from the cartilage by overnight digestion in 0.1% collagenase/DMEM. The released cells are expanded as primary cells in a suitable medium such as the DM of this invention or DMEM containing 10% FBS. Cells can be passaged at 80-90% confluence using 0.05% trypsin-EDTA, diluted for subculture, and reseeded for second and subsequent passages to allow for further expansion. At any time, trypsinized cells can be frozen in DMEM containing 10% DMSO and 40% HSA or in other compositions known in the art, e.g., as described in U.S. Pat. No. 6,365,405. [0046] It may be desirable in certain circumstances to utilize chondrocyte progenitor stem cells such as mesenchymal stem cells rather than cells from cartilage biopsies that are already differentiated into chondrocytes. Examples of tissues from which such stem cells can be isolated include placenta, umbilical cord, bone marrow, skin, muscle, periosteum, or perichondrium. Chondrocytes can be obtained by inducing differentiation of such cells into chondrocytes in vitro. [0047] The term “chondrocytes,” as used herein, refers not only to mesenchymal stem cells, but also to cells that can be trans-differentiated into chondrocytes, for example, adipocytes, osteocytes, fibroblasts, and myocytes. The term “chondrocytes” also refers to chondrocytes that are passaged or dedifferentiated. [0048] The term “low density” refers to seeding densities less than 20,000 cells/cm 2 . [0049] The methods of this invention are suitable for cells growing in cultures under various conditions including, but not limited to, monolayers, multilayers, on solid support, in suspension, and in 3D cultures. [0050] Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. EXAMPLES [0051] Various aspects of the invention are further described and illustrated in the examples presented below. Example 1 [0052] Human articular cartilage biopsy samples from donors of 16-51 years of age were trimmed of extraneous material, minced and subjected to enzymatic digestion using 0.25% protease from Bascilus Thermopropolipycus for 1-2 hrs followed by an overnight digestion in 0.1% collagenase/DMEM at 37° C. Isolated articular chondrocytes were washed twice in DMEM containing 10% human serum albumin (DMEM/10% HSA). The isolated primary human articular chondrocytes (HAC) were seeded at 5,000-6,000 cells/cm 2 in T75 flasks using the following separate media conditions: 1) DMEM/10% FBS (DMEM supplemented with 10% fetal bovine serum and 100 μg/ml gentamycin); 2) cDRF (as defined in Table 3); 3) cDRF/P (cDRF supplemented with 10 ng/ml PDGF); 4) cDRF/L (cDRF supplemented with 5 μl/ml CDLM (as defined in Table 4)); and 5) cDRF/P/L (cDRF supplemented with 10 ng/ml PDGF and 5 μl/ml CDLM) [0058] Two flasks were used per each condition. At the end of each passage, nearly confluent cells were harvested by trypsinization, counted, washed in DMEM/10% HSA and reseeded at 5,000-6,000 cells/cm 2 in the corresponding media. Cell yield was calculated as the average of duplicate samples for each condition. A comparison of cell yields at the end of each passage for chondrocytes propagated under media condition defined above is represented in Table 6. The results of this experiment demonstrate that regardless of the passage number, cell yields were higher for chondrocytes passaged in cDRF/P/L, as compared to either DMEM/10% FBS or cDRF. The effect was more pronounced for higher passage numbers. TABLE 6 Cell Yield per T75, ×10 7 Passage Medium 1 2 3 4 5 DMEM/10% FBS 0.95 0.6 0.25 0.24 0.3 cDRF 0.59 0.75 0.90 1.05 0.8 cDRF/P/L 1.9 2.8 1.2 2.25 2.05 Example 2 [0059] Hyaline cartilage biopsy samples collected from multiple donors were used to compare cell yields as a function of the passage number for chondrocytes cultured in DMEM/10% FBS or in a completely defined serum-free medium according to this invention. Samples were collected and treated as described in Example 1. Isolated chondrocytes were washed twice in DMEM containing 10% human serum albumin (DMEM/10% HSA). The isolated primary human articular chodrocytes (HAC) were seeded at 6,000 cells/cm 2 in T75 flasks using the following media conditions: 1) DMEM/10% FBS (DMEM supplemented with 10% fetal bovine serum and 100 μg/ml gentamycin); and 2) cDRF/P/L (cDRF supplemented with 10 ng/ml PDGF and 5 μl/ml CDLM) [0062] At the end of each passage nearly confluent cells were harvested by trypsinization, counted, washed in DMEM/10% HSA and reseeded at 6,000 cells/cm 2 in respective media. A comparison of cell yields at the end of each passage for chondrocytes propagated in DMEM/10% FBS or cDRF/P/L is shown in Table 7. Cell yields were higher in cDRF/P/L as compared to DMEM/10% FBS for cells in passages 1-3, and significantly higher (p=0.05) for cells in passage 4. TABLE 7 Passage 1 2 3 4 DMEM/10% FBS Cell Yield (×10 4 /cm 2 ) 7.5 ± 2.3  8.5 ± 2.4   5 ± 2.7   4 ± 2.0 Number of Samples 9 8 5 3 cDRF/P/L Cell Yield (×10 4 /cm 2 ) 9.6 ± 7.0 12.5 ± 4.5 9.0 ± 5.0 14.0 ± 6.3 Number of Samples 8 8 3 3 T-test p-value 0.43 0.07 0.10 0.05* Example 3 [0063] In this experiment, human articular chondrocytes from three donors, ages 16, 22, and 55, were isolated and treated as described in Example 1. Chondrocytes were seeded at 6,000 cells/cm 2 in T75 flasks and grown in DMEM/10% FBS until near confluence. The cells were then harvested by trypsinization, washed in seeding media, and immediately frozen in 10% DMSO/40% HSA/50% DMEM. For the second passage, ampules of frozen cells were thawed out, rinsed in DMEM/10% HSA and reseeded at 3,000-4,000 cells/cm 2 in the following media: 1) DMEM/10% FBS; 2) cDRF; 3) cDRF/P; and 4) cDRF/P/L (see Example 1 for the description of the media). Two flasks were used per each set of media conditions. At the end of each passage nearly confluent cells were harvested by trypsinization, washed in DMEM/10% HSA and reseeded in the corresponding media. At the end of the third passage, cells were harvested and counted. Growth index expressed as a number of doublings per day at the end of a seven-day period was calculated as the mean value for the three donor samples, with each sample being represented by the average of duplicates derived from the donor. A comparison of growth index for chondrocytes propagated in DMEM/10% FBS and in completely defined serum-free media is illustrated in FIG. 1 . Growth index for chondrocytes propagated in DMEM/10% FBS and those propagated in cDRF/P/L were comparable whereas cells propagated in cDRF/P or cDRF had slightly lower growth index. Chondrocytes grown as monolayer in DM of the invention did not have the typical fibroblastic morphology when compared with chondrocytes grown in DMEM/10% FBS, but had a very distinct cell shape with well defined borders. Example 4 [0064] In this experiment, the dependence on the seeding density was investigated. Human hyaline articular chondrocytes were obtained from the same donors and treated as described Example 3, except each sample was split into three to be seeded at 6,000; 4,000, and 2,000 cells/cm 2 . At the end of each passage, cells were reseeded at the original seeding density of that set. At the end of the third passage, cells were harvested, counted and cell yield was calculated for chondrocytes propagated in DMEM/10% FBS or in DM of this invention. The results of the experiment are presented in FIG. 2 . Chondrocytes grown in cDRF/P/L had at least comparable or higher yields than cells grown in DMEM/10% FBS or cDRF/P, whereas cells propagated in cDRF had slightly lower yields as compared to DMEM/10% FBS. The difference was more pronounced for cells passaged at seeding density of 6,000 cells/cm 2 . Additionally, cells grown in cDRF or cDRF/P had higher yields at higher seeding densities. Example 5 [0065] To assess the redifferentiation potential of chondrocytes after their expansion in monolayer culture in DM of this invention, the chondrocytes' capacity to form cartilaginous tissue was examined. Chondrocytes were isolated and treated as described in Example 2. At the end of the second passage chondrocytes were trypsinized, rinsed in DMEM/10% FBS and seeded as described below on Millicell-CM® filter inserts (12 mm diameter, 0.4 μm pore size, Millipore Corp., Bedford, Mass.). The filters were pre-coated with type II collagen (0.5 mg/ml 0.012N HCl) [Sigma St. Louis, Mo.]. Chondrocytes were seeded at 2×10 6 cells/cm 2 on top of the filter in DMEM/20% FBS or in a DMEM-based differentiation medium (DMEM supplemented with 2 mg/ml HSA, 5 μg/ml linoleic acid, 2% ITS). The cultures were maintained at 37° C. in a humidified atmosphere supplemented with 5% CO 2 . After three days in culture 100 μg/ml ascorbic acid, 5 ng/ml TGF-β2 and 10 ng/ml PDGF-BB were added to the media. The media were changed every two days. After 1 week, the chondrocyte cultures on the filter inserts were harvested at selected intervals and fixed in 10% formalin, embedded in paraffin and cut in 5 μm sections that were then stained with toluidine blue or safranin-◯. These reagents stain sulphated proteoglycans. Sulphated glycosaminoglycans were quantified using a modified dimethylmethylene blue assay according to the procedure described by Farndale et al. ( Biochimica et Biophyca Acta 883:173-177, 1986). [0066] Immunohistochemical analysis on the paraffin-embedded sections was performed to analyze expression of type II collagen. Primary antibodies for type II collagen (Biodesign International, Kennebunkport, Me.) were used at 1:50 dilution. The reaction was carried out in a humid atmosphere at 37° C. for one hour. The tissue sections were then washed 3 times in Phosphate Buffered Saline (PBS) and incubated with a 1:200 dilution of rhodamine-conjugated goat anti-rabbit IgG in PBS as a secondary antibody, under the same conditions as described for the primary antibodies. Hoechst dye at 1 μg/ml was included in some experiments with the secondary antibody for nuclear staining. The sections were washed three times in PBS and examined under a fluorescence microscope. [0067] Histological examination of the cultures showed that the chondrocytes passaged in cDRF/P/L accumulated an extracellular matrix, which contained proteoglycans and collagen, and formed a continuous layer of cartilaginous tissue. These chondrocytes showed an increase in the amount of tissue produced and the matrical staining of proteoglycans when compared with chondrocyted propagated with DMEM/10% FBS. The cells propagated in cDRF/P/L readily underwent differentiation from a monolayer to round cells with lacunae chondrogenic morphology and expressed more type 11 collagen as compared to DMEM/10% FBS. The results of this experiment demonstrate that chondrocytes propagated in DM of the invention, are capable of re-expressing their chondrocyte phenotype, i.e., they retain their redifferentiation potential. The results also demonstrate the feasibility of producing preformed cartilage grafts from propagated chondrocytes isolated and expanded in DM of the invention. Example 6 [0068] Normal adult human articular chondrocytes dedifferentiate as a consequence of expansion in monolayer in vitro. To confirm that chondrocytes cultured in DM of the invention have retained their capacity to redifferentiate, a TaqMan analysis of gene expression of cartilage-specific markers was performed. The analysis of gene expression begins with the isolation of quality total RNA from ex vivo formed cartilagenous tissue and normal articular cartilage. [0069] Initially, chondrocytes were isolated and treated and expanded in DMEM/10% FBS or cDRF/P/L described in Example 2. These cultures were then harvested at 1, 2, 3, and 4 weeks from seeding on the filter inserts. Subsequently, chondrocytes cultures were grown on Millicell-CM® filter inserts as described in Example 5. Gene expression was analyzed for the following proteins: aggrecan, type I collagen, type II collagen, type X collagen, osteocalcin, osteopontin, and versican. [0070] Total RNA was isolated using a modification of a published protocol (Reno et al. (1997) Biotechniques 22: 1082-1086). First total RNA is isolated from the tissue using the TRIzol reagent (catalog #15596-026, Invitrogen Life Technologies, Carlsbad, Calif.) along with mechanical homogenization using a handheld tissue homogenizer. The isolated RNA was resuspended in 10 μl of nuclease-free water and purified over a RNeasy Mini spin column (calalog #74104, QIAGEN, Valencia, Calif.) following a protocol as supplied by the manufacturer. Contaminating genomic DNA is removed using DNA-free kit (catalog #1906, Ambion, Austin, Tex.). An equal amount of total RNA was taken from each sample and reverse-transcribed (RT) using beads with an oligo-dT primer (catalog #27-9264-01, Amersham Biosciences, Piscataway, N.J.). A Picogreen assay ( catalog # P-7589, Molecular Probes, Eugene, Oreg.) was performed to measure the efficiency of the RT reaction. Next, a TaqMan assay was performed to quantify of the absolute copy number of each gene using 25 ng of starting material from each sample. The number of gene copies was determined for each gene using a standard curve created with commercially available plasmid standards. The final results were adjusted in accordance with results of the PicoGreen assay. [0071] The results of a TaqMan assays for samples from two subjects are presented in FIGS. 3A and 3B . These results demonstrate a sustained (2-4 weeks) elevated expression of the type II collagen gene, a major marker for articular cartilage, in cells propagated in DMEM/P/L. The results of this experiment confirm that that chondrocytes propagated in DM of the present invention retain their capacity to re-express the chondrocyte phenotype. The results also demonstrate the feasibility of producing preformed cartilage grafts from propagated chondrocytes isolated and expanded in DM of the invention. [0072] The specification is most thoroughly understood in light of the teachings of the references cited within the specification, all of which are hereby incorporated by reference in their entirety. The embodiments within the specification provide an illustration of embodiments of the invention and should not be construed to limit the scope of the invention. [0073] Unless otherwise indicated, all numbers expressing quantities of ingredients, cell culture conditions, and so forth used in the specification, including claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless otherwise indicated to the contrary, the numerical parameters are approximations and may very depending upon the desired properties sought to be obtained by the present invention. A skilled artisan will recognize that many other embodiments are encompassed by the claimed invention and that it is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

The present invention provides defined serum-free cell culture media useful in culturing fibroblasts, especially articular chondrocytes, that avoids problems inherent in the use of serum-containing media. The defined media comprise platelet-derived growth factor (PDGF), and chemically defined lipids, or combinations of these compounds. In another aspect, the present invention also provides tissue culture methods that comprise incubating chondrocytes in the defined serum free media. The methods enhance attachment and proliferative expansion of chondrocytes seeded at low density while maintaining their redifferentiation potential.

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of the U.S. Provisional patent application No. 60/214,438 filed on Jun. 28, 2000, the contents of which are incorporated herein by reference. TECHNICAL FIELD The present invention relates generally to food trays, and more particularly to food trays having selectively deployable condiment compartments. BACKGROUND OF THE INVENTION Finger foods, such as chicken nuggets, popcorn shrimp, french fries, and onion rings, are often served in paperboard trays. These trays have flat bottom walls and side walls that extend upwardly therefrom at an angle to define a top opening larger than the bottom wall. In the interest of space efficiency, these trays are preferably stackable or nestable so that one tray fits inside another tray. This allows large stacks of trays to be shipped and stored in a relatively small space until needed. Many of the above foods are frequently eaten with condiments such as ketchup, cocktail sauce, and barbeque sauce. Since these foods are often eaten with one's fingers, a person typically holds a food item in his fingers and dips it into a condiment. When eating in a sit-down restaurant, the condiment may be dispensed directly into the paperboard tray next to or on top of the food product, or a tub of the condiment can be placed on a table next to the consumer. When consuming such products in an automobile or while walking, however, the option of using a tub of condiment becomes more difficult. Furthermore, because semi-liquid condiments tend to run, it is difficult to keep the condiments and food products separate, and a user is often left with some products that are substantially covered with condiment and with condiment spread over the entire bottom wall of the container. The more the container is moved during use, the more the condiment is likely to move. Fast food containers having a condiment compartment, such as the one shown in U.S. Pat. No. 4,126,261 for “Disposable Food Tray With Condiment Container” issued to Cook on Nov. 21, 1978, are known in the prior art. However, in the first embodiment of the invention shown in the '261 patent, a condiment holder must be formed from a separate piece of material and then affixed to the main container, resulting in increased assembly costs. In the second embodiment of the invention shown in the '261 patent, the condiment holder is made from the same blank as the tray, but produces a finished product that is not stackable. It would therefore be desirable to produce a stackable tray having an integral condiment compartment formed from a unitary blank of material. SUMMARY OF THE INVENTION These problems and others are addressed by the present invention which comprises a novel tray structure that is stackable and nestable and that includes one or more fold-out walls that form at least one compartment for holding a condiment substantially separate from a food product. The invention also comprises a unitary blank for making such a tray which blank is cut form a sheet of stock material in a manner that makes efficient use of the material, minimizes waste, and provides for an accurate assembly of the food tray. According to the invention, a tray includes a movable wall or panel foldable between a first position flush with one or more sidewalls of the tray and a second position spaced apart from the one or more sidewalls to define a compartment between the sidewalls and the movable wall. This arrangement allows trays to be stacked and nested when the movable wall is in a stowed position flush with a side wall. When the condiment compartment is in its stowed position, the trays can also be used in the same manner as ordinary trays. To use the condiment compartment, it is merely necessary to flip the wall inwardly from the sidewall. The flexibility of the wall allows the wall to be shifted with very little effort. In a first embodiment of the invention, the condiment compartment is formed across a corner of the tray and connected to two adjacent tray sidewalls. When flipped open into a deployed position, a pyramidal condiment compartment is formed in one corner of the tray. In a second embodiment, a movable wall is formed between two parallel sidewalls of the tray. When flipped open, the wall defines a compartment spanning the length or width of the rectangular tray between the movable wall and one of the tray sidewalls. In a third embodiment, the tray includes two condiment compartments along opposite sides of the rectangular compartment each formed by a moveable wall. In a fourth embodiment, the tray is formed much like the tray of the second embodiment but the top edge of one tray wall and the top edge of the movable wall forming the condiment compartment have curved portions to provide for an increased gripping surface. It is therefore a primary object of the present invention to provide a stackable container having an interior wall that can be deployed to form an interior compartment. It is a further object of the present invention to provide a stackable container having a secondary compartment formed from a unitary blank of material. It is another object of the present invention to provide a stackable food tray having a selectively deployable condiment compartment. It is still a further object of the present invention to provide a food tray having a deployable corner compartment. It is still another object of the present invention to provide a stackable food tray having a condiment compartment that is shiftable between a use and a storage position. It is yet another object of the present invention to provide a unitary blank for forming a food tray having the above characteristics. These features and advantages will be better appreciated and understood by those skilled in the art after reading the following detailed description of several preferred embodiments of the invention in connection with the drawings and appended claims. BRIEF DESCRIPTION OF DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings, of which: FIG. 1 is a perspective view of a food tray having a condiment compartment according to a first embodiment of the invention; FIG. 2 is a right side elevation view of the tray of FIG. 1; FIG. 3 is a front elevation view of the tray of FIG. 1; FIG. 4 is a top plan view of the tray of FIG. 1 with the condiment compartment wall in a stowed position; FIG. 5 is a top plan view of the tray of FIG. 1 with the condiment compartment wall in a deployed position; FIG. 6 is a plan view of a blank for forming the tray of FIG. 1; FIG. 7 is a perspective view of a food tray according to a second embodiment of the present invention having two condiment compartments both shown in deployed positions; FIG. 8 is a left side elevation view of the tray of FIG. 7; FIG. 9 is a front elevation view of the tray of FIG. 7; FIG. 10 is a top plan view of the tray of FIG. 7 showing only one of the two compartments in a deployed position; FIG. 11 is a plan view of a blank for forming the tray of FIG. 7; FIG. 12 is a top plan view of a food tray according to a third embodiment of the present invention; FIG. 13 is a plan view of a blank for forming the tray of FIG. 12; FIG. 14 is a front elevational view of a food tray according to a fourth embodiment of the invention; and, FIG. 15 is a plan view of a blank for forming the tray of FIG. 14 . DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, wherein the showings are for the purpose of illustrating several embodiments of the invention only and not for the purpose of limiting same, FIG. 1 illustrates a food tray 10 that is assembled by folding and gluing a unitary blank 12 of paperboard stock. To facilitate the description of the present invention, the tray will be generally described in a position in which it is normally used by a consumer, that is, with the opening for food at the top and with the bottom wall resting on a flat support surface (not shown). Referring to FIGS. 1-6, tray 10 includes a food compartment 11 and a condiment compartment 13 . Food compartment 11 has a pair of opposed first and second sidewalls 18 , 20 , a front wall 22 , a rear wall 24 , and a bottom panel 26 . First sidewall 18 has an upper edge 28 , and is joined with bottom panel 26 along a first fold line 32 . First and second triangular glue flaps 34 , 36 are coextensive and integral with the edges of first sidewall 18 and are connected thereto at a second fold line 38 and a third fold line 40 respectively. Second and third fold lines 38 , 40 are outwardly divergent, making first sidewall 18 trapezoidal. Second triangular glue flap 36 has a concave upper edge portion 42 which, as will be explained hereinafter, provides access to the condiment compartment movable wall so that wall can be moved. Second sidewall 20 has an upper edge 44 , and is joined with the bottom panel edge along a fourth fold line 48 generally running parallel to first fold line 32 . Third and fourth triangular glue flaps 50 , 52 are integral with rear and front edges of second sidewall 20 and are joined to the second sidewall along a fifth fold line 54 and a sixth fold line 56 respectively, which the fold lines are mutually divergent. Rear wall 24 is trapezoidal, includes an upper edge 60 , and is joined at its lower edge with the rear edge of the bottom panel along a seventh fold line 62 generally perpendicular to first and fourth fold lines 32 , 48 . Rear wall 24 further includes slanted side edges 64 , 66 . Front wall 22 has an upper edge 68 , and a bottom edge that meets bottom panel 26 along an eighth fold line 72 generally parallel to seventh fold line 62 . Front wall 22 also includes two opposed slanted side edges 74 and 76 and a concave upper edge portion 78 which overlays the concave edge portion 42 of second triangular glue flap 36 when condiment compartment 13 is in a stowed position. Condiment compartment 13 , which is more specifically defined as the area between first and second triangular walls 80 and 82 , a portion of first sidewall 18 , and a portion of front wall 22 , and which is integral with the food compartment, includes a first triangular wall 80 , a second triangular wall 82 joined and coextensive with first triangular wall 80 along a ninth fold line 90 , a first condiment compartment glue flap 84 joined and integral with first triangular wall 80 along a tenth fold line 88 , and a second condiment compartment glue flap 86 integral and coextensive with second triangular wall 82 along an eleventh fold line 92 . First glue flap 84 is joined and integral with upper edge 68 of front wall 22 along a twelfth fold line 94 from which second portion 16 as a whole is attached to first portion 14 of unitary blank 12 . First triangular wall 80 of condiment compartment 13 has a convex edge portion 96 along its upper edge where, in the folded configuration of the condiment compartment, convex edge portion 96 extends peripherally beyond concave edge portion 78 of the front wall 22 and concave edge portion 42 of second triangular glue flap 36 . Convex edge portion 96 provides a gripping location at which the condiment compartment walls can be gripped and pulled out into a deployed or use position. In the preferred embodiment, first and second triangular walls 80 , 82 are generally isosceles. That is, tenth fold line 88 , ninth fold line 90 , and eleventh fold line 92 all have about the same length. Moreover, as best seen in FIGS. 5 and 6, the distance between a first point A and a second point B in the assembled, and deployed, condiment compartment 13 is less than the distance between point C and point D of the second portion of panel 16 . These relative distances, as will be explained herein, provide for a snap-out deployment of condiment compartment 13 which allows condiment compartment 13 to stay in a deployed configuration without any condiment inside. As best seen in FIG. 5, condiment compartment 13 has an inverted pyramid shape in its deployed position. It should also be appreciated that the bottom portion of the inverted pyramid shaped condiment compartment is held closely against the lower edge of the front wall of the tray. That is, edge 98 of first glue flap 84 overlays eighth fold line 72 of the tray. The assembly of tray 10 will now be explained with reference to the blank shown in FIG. 6 . First sidewall 18 is folded up along first fold line 32 toward bottom panel 26 . Second sidewall 20 is folded up along fourth fold line 48 toward bottom panel 26 . Rear wall 24 is then folded up along seventh fold line 62 . Next, first triangular glue flap 34 is folded along second fold line 38 inwardly where side edge 66 coincides with second fold line 38 and then glue flap 34 is adhesively bonded onto the back surface of rear wall 24 . Similarly, third triangular glue flap 50 is folded along fifth fold line 54 inwardly and behind rear wall 24 until side edge 64 coincides on top of fifth fold line 54 and then third triangular glue flap 50 is adhesively bonded to the back surface of rear wall 24 . Second and fourth triangular glue flaps 36 and 52 are folded along third and sixth fold lines 40 and 56 , respectively, and are adhesively bonded to the back surface of front wall 22 , where side edge 76 coincides on top of third fold line 40 , and side edge 74 coincides on top of sixth fold line 56 . At this point, food compartment 11 of tray 10 is assembled. Now, the assembly of condiment compartment 13 , which is integral with the food compartment will be described. Second triangular wall 82 is folded under first triangular wall 80 along ninth fold line 90 and the two triangular walls are symmetrically placed on top of one another. Eleventh fold line 92 coincides along tenth fold line 88 as second condiment glue flap 86 partially overlays on first condiment glue flap 84 . Next, second portion 16 as a whole is folded up and into the food compartment along twelfth fold line 94 until first triangular wall 80 and first condiment glue flap 84 are flush with front wall 22 of tray 10 . At this point, upper edge 98 of first glue condiment flap 84 becomes aligned with and eighth fold line 72 . First condiment glue flap 84 is adhesively bonded to the interior surface of front wall 22 . First triangular wall 80 is free to fold along tenth fold line 88 . Also, second triangular wall 82 is free to fold along ninth fold line 90 . Second condiment glue flap 86 is adhesively bonded to the interior side of first sidewall 18 at a location and position which is determined by aligning ninth fold line 90 with third fold line 40 and second triangular wall 82 flush with first wall 18 . This results in the stowed configuration of the condiment compartment. In order to deploy the condiment compartment, the user pulls convex edge 96 of first triangular wall 80 in the direction of the interior of the food compartment. The first and second triangular walls 80 and 82 are flexible thus bend to allow the wall to shift from the stowed position shown in FIG. 4 to the deployed position shown in FIG. 5 . As stated earlier, because the distance between points C and D is longer than the distance between points A and B, the wall snaps open into a deployed position and remains deployed even with no condiment inside. Referring now to FIGS. 12 and 13, a second embodiment of the invention is illustrated. In this embodiment, elements common to the first embodiment are identified by like numerals. The condiment compartment in this embodiment is elongated, spans the width of the tray and deploys and stows relative to the front wall of the tray. Of course, this compartment could also be formed along one of the long sides of the rectangular tray or along the rear wall of the tray. A flap 100 is attached to front wall 22 along a perforated cut line 102 , and spans the width of the upper edge of front wall 22 . When folded over front wall 22 and attached thereto as described below, this flap will form a condiment compartment 113 having a main wall 104 . Condiment compartment 113 shown in an open position in FIG. 12, further includes a first triangular portion 106 integral with main wall 104 along a fourteenth fold line 118 on one side, and integral with a third glue flap 108 along a fifteenth fold line 120 on the opposing side. A second triangular portion 110 is integral with main wall 104 along a sixteenth fold line 116 on one side, and is joined and integral with a fourth glue flap 112 along a seventeenth fold line 114 . A glue flap 124 is integral with the lower edge of main wall 104 along an eighteenth fold line 122 . Fourteenth and sixteenth fold lines 116 , 118 are divergent. It should be appreciated that condiment compartment 113 is the area confined between first and second triangular portions 106 and 110 , main wall 104 , front wall 22 , and is closed off on the corners along the fifteenth and seventeenth fold lines 120 and 114 , and on the bottom along eighth fold line 72 of bottom panel 26 . All edges of the condiment compartment are glued to the sidewalls and/or bottom wall of the tray thus providing a good seal to hold a condiment in place. As stated hereinabove, main wall 104 is joined with front wall 22 on the unitary blank along the perforated thirteenth line 102 , which may is scored along most of its length and connected to wall 22 at a small number of locations. This arrangement holds panel 100 to wall 22 during manufacture and assembly, but allows a user to easily break the connections between wall 22 and panel 100 when the tray is assembled so that the condiment compartment can be deployed. The food compartment is assembled in the same way as the first embodiment explained hereinabove. The condiment compartment 113 is assembled as follows: First, top portion 124 is slightly folded outwardly along eighteenth fold line 122 . Next, main wall 104 is folded inwardly into the food compartment along thirteenth fold line 102 and is placed flush with front wall 22 . Eighteenth fold line 122 overlays eighth fold line 72 and top portion 124 rests on the top surface of bottom panel 26 and is adhesively bonded thereon. Fourth glue flap 112 is adhesively bonded to the inner surface of second sidewall 20 and seventeenth fold line 114 overlays sixth fold line 56 and side edge 74 of front wall 22 . Similarly, at the opposing side, third glue flap 108 is adhesively bonded to the inner surface of first sidewall 18 in such configuration that fifteenth fold line 120 overlays third fold line 40 and side edge 76 of front wall 22 . Therefore, second portion 100 is adhesively bonded and secured to first portion 14 where in the stowed position and configuration of the condiment compartment, main wall 104 is flush with front wall 22 , bottom portion 124 is secured on the top surface of bottom panel 26 , and third and fourth glue flaps 108 , 112 are secured to first and second sidewalls 18 , 20 . To deploy condiment compartment 113 , main wall 104 is pulled away from front wall 22 breaking the few connections therebetween. As best seen in FIG. 12, the distance E-F-G-H is greater that the distance between points E and F, and therefore, when panel 104 is moved away from front wall 22 , front panel 22 and the triangular panels 106 and 110 are deformed until panel 104 reaches the position shown in FIG. 12 . Because these panels also need to be deformed to move panel 104 back against front wall 22 , the condiment compartment tends to stay in an open position, even when it is empty. Referring now to FIGS. 7-11, a third embodiment of the invention is illustrated. This embodiment is identical to the second embodiment described above, except a second identical condiment compartment is utilized at the opposing side of the tray along rear wall 24 . Reference numerals with primes are used to designate portions of the second compartment, for example the second compartment 113 ′ includes a wall 104 ′ corresponding to wall 104 of the second embodiment. The production and assembly of this embodiment will easily be understood from reading the above description of a tray having single compartment spanning its width and will not be described further. A fourth embodiment of the invention is shown in FIGS. 14 and 15. This embodiment is substantially the same as the second embodiment described above except in the area of the top edges of the front wall and the condiment compartment wall. FIG. 14 shows a front view of a fourth embodiment of the invention. The container includes a front wall 220 having a top edge 222 which includes first and second linear outer portions 224 , 226 and a sinusoidal central portion having a first arched section 228 curving away from front wall 220 and a second arched section 230 cut into front wall 220 . The panel further includes a wall 232 that shifts to form a condiment compartment as described above. Wall 232 has a top edge 234 with a first portion 236 arching away from the center of wall 232 and a second portion 238 cutting into wall 232 . When the container is assembled, first arched section 236 of wall 232 overlies the second arched section 230 of front wall 220 . This arrangement produces a wall for forming a condiment compartment that functions substantially the same as the previous embodiment but which provides an increased gripping surface to make the condiment compartment wall 232 easier to separate from front wall 220 . A blank for forming a tray according to this embodiment is shown in FIG. 15 . While preferred embodiments have been shown and described, various modifications and changes may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration only, and such illustrations and embodiments as have been disclosed herein are not to construed as limiting to the claims.

A food tray for holding food and a condiment is formed from a unitary paperboard blank. The food tray has a food compartment and a condiment compartment, and the condiment compartment is deployable from a stowed position overlaying one or more sidewalls of the food compartment to a deployed position for holding condiments. Multiple trays can be stacked in a nested fashion when the condiment compartment is stowed.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention relates generally to unmanned parachutes for cargo drops. More particularly, it relates to a control system and method for targeted landing of cargo using controllable parachutes. [0003] 2. Discussion of Related Art [0004] Parachutes have evolved over the years into highly sophisticated systems, and often include features that improve the safety, maneuverability, and overall reliability of the parachutes. Initially, parachutes included a round canopy. A skydiver was connected to the canopy via a harness/container to suspension lines disposed around the periphery of the canopy. Such parachutes severely lacked control. The user was driven about by winds without any mechanism for altering direction. Furthermore, such parachutes had a single descent rate based upon the size of the canopy and the weight of the parachutist. [0005] In the mid-1960's the parasol canopy was invented. Since then, variations of the parasol canopy have replaced round canopies for most applications, particularly for aeronautics and the sport industry. The parasol canopy, also known as a gliding or ram air parachute, is formed of two layers of material—a top skin and a bottom skin. The skins may have different shapes but are commonly rectangular or elliptical. The two layers are separated by vertical ribs to form cells. The top and bottom skins are separated at the lower front of the canopy to form inlets. During descent, air enters the cells of the canopy through the inlets. The vertical ribs are shaped to maintain the canopy in the form of an airfoil when filled with air. Suspension[s] lines are attached along at least some of the ribs to maintain the orientation of the canopy relative to the pilot. The canopy of the ram air parachute functions as a wing to provide lift and forward motion. Guidelines operated by the user allow deformation of the canopy to control direction and speed. Ram air parachutes have a high degree of lift and maneuverability. [0006] Despite the increased lift from a ram air parachute, round canopies are still used for cargo drops. However, as the weight of cargo increases, the size of the canopy must increase to obtain an appropriate descent rate. Reasonable sizes of round parachutes greatly limit the amount of cargo which can be dropped. Therefore, a need exists for a parachute system which can carry additional cargo weight. Additionally, accurate placement of cargo drops from high altitude with round parachutes is impossible. Adjustments can be made for prevailing winds at various altitudes but the cargo is likely to be drift off course due to variations. Furthermore, improvements in surface-to-air missiles requires higher altitude drops in order to protect aircraft. In military use, round parachutes are generally used from an altitude around one thousand (1000) feet to ensure accurate placement. However, new, inexpensive, hand held surface-to-air missiles can put in jeopardy airplanes up to twenty-five thousand (25,000) feet in altitude. Current military technique is to use a special forces soldier to pilot both parachute and cargo to the ground from altitudes of twenty-five to thirty-five thousand (25-35,000) feet. This limits cargo to six hundred fifty (650) pounds, as it must be attached to a human. Therefore, a need exists for an autonomous guided parachute system for cargo which can operate at high altitudes as well as scale to heavier cargo weights. [0007] Autonomous ram air parachutes systems have been developed for cargo drops but suffer from several problems that have prevented them from being generally adopted into military techniques. Prior art guided systems include a harness/container system, a single parachute, flight computer, guidance and navigation control software, a GPS, and electric motor actuators. The flight computer must calculate a flight path and glide the system from the drop point all the way to the ground target. In order for the flight computer to accomplish this, the parachute used must be of low wing loading to ensure docile and slow flight. Such lightly loaded parachutes fly with free flight forward speeds of approximately twenty-five (25) miles per hour or slower. Typical wing loadings are around one (1) pound per square foot of wing area. Such slow systems present several problems, first they are greatly effected by winds aloft. At high altitudes winds are quite strong and can be several times the forward speed of the wing. This necessitates the need to map out specific winds at each altitude by dropping radio frequency transmitting sensors units. The collected data must be analyzed and imported to the autonomous systems flight computer to enable a drop position to be calculated and then a flight path. Another problem is the systems time in the air with such light wing loaded parachutes is quite long, increasing their vulnerability and delivery time. Another problem is that higher weight cargo requires proportionally larger wings which become completely impractical far below the maximum weight desired for military use. Therefore, a need exists for an improved autonomous guided parachute system which can provide accurate targeting control from high altitudes, while flying at higher speeds to reduce or negate wind effects, and be able to scale to the ultimate high weight cargo required by militaries. [0008] Typically, static line deployment is used for cargo drops. A line from the harness/container is attached to the cargo hold of the delivery aircraft. The cargo is then pushed out of the hold. The line causes the parachute to be deployed, with or without the use of a drogue. However, air currents around the delivery aircraft can interfere with proper deployment of a gliding parachute using a static line. Also, the cargo is not typically falling stable upon immediate exit which can cause difficulties during opening of the gliding parachute. In order to slightly delay opening, existing systems utilize a double-bag deployment system. However, the double-bag system is complicated and expensive to construct as well as complicated to pack. Therefore, a need exists for an improved system for delaying the deployment of a gliding parachute. [0009] Additionally prior art systems use electric motor actuators and batteries. Typically the motors are overly complicated DC servo drive motors. At high altitudes temperatures are very low. Such systems suffer from the requirement for very large, low power density cold weather batteries. To meet military demand high altitude systems must operate up to −65 F and existing systems do not function at such temperatures. As such there exists a need for lighter simpler actuators and power system that are unaffected by extreme temperatures. SUMMARY OF THE INVENTION [0010] The deficiencies of the prior art are substantially overcome by the guided, multi-stage parachute system of the present invention. According to an aspect of the invention, the parachute system includes two different kinds of parachutes for use during different phases of the cargo drop process. The requirements of guidance and soft landing have been separated. A fast, high performance ram air parachute is used to guide the cargo in substantially a straight line from exit point to substantially overhead of the target location and then rapidly spiral dive down to lose altitude. The system transitions to a larger unguided landing parachute prior to impact. The multi-stage parachute system utilizes the advantages of different kinds of parachutes to achieve greater control and improved performance. Since the gliding parachute is not used for landing of the cargo, it can be designed for extremely high speed and high wing load capabilities. These features allow higher reliability in high altitude drops by limiting the effect of winds and greatly reduce time aloft. Since the landing parachute is not used to control location, it can be designed for a soft landing of large cargos. Also, it can be deployed at the lowest possible altitudes to minimize unguided drift. [0011] According to another aspect of the invention, a novel flight controller provides control for the parachute system. The flight controller determines the position and altitude of the parachute system. The flight controller operates the steering controls of the guidance parachute. Once within a specified radius of overhead the target location, the flight controller further operates steering controls of the guidance parachute for a rapid, controlled descent overhead the target location until a predetermined minimum altitude is reached. Once the predetermined altitude is reached, the flight controller releases the guidance parachute to transition to the landing parachute. [0012] According to another aspect of the invention, static line drogue deployment of the parachute system is performed with a time delay on releasing the drogue to extract and deploy the main. The time delay may be a mechanical delay or may be controlled by the flight controller. The time delay allows the system to stabilize under drogue before deployment of the main guidance wing. [0013] According to other aspects of the invention, the release of the guidance parachute operates to static line deploy the landing parachute. According to another aspect of the invention, a two stage harness is used to attach the parachute system to the cargo. During transport and release of the cargo from the airplane, the parachute system is closely attached to the cargo. Following deployment of the drogue chute, the parachute system is spaced further away from the cargo. [0014] According to another aspect of the invention, the parachute system of the invention is used with explosive cargo to create a “smart” bomb. The gliding parachute and flight controller are used to steer the explosive cargo over a desired target location. The landing parachute may be used to land the explosive cargo when it is over the target location. Alternatively, according to another aspect of the invention, a landing parachute is not used. The gliding parachute is used to fly the explosive cargo at high speed into the target or the flight controller detonates the explosive at a preset altitude over the target. [0015] According to another aspect of the invention, a flight controller determines position of the parachute system using GPS signals and controls the guidance parachute to reach a desired destination. [0016] According to another aspect of the invention, the flight controller logs position and control information and optional sensor data during flight. The flight controller includes a microprocessor and memory. During flight, in order to control the parachute, the flight controller determines the position and altitude of the parachute system. This information can be recorded at predetermined intervals. Information from the memory can be retrieved to analyze performance of the flight controller and the parachute system. [0017] According to another aspect of the invention, the flight controller includes a transceiver, preferably a radio frequency transceiver. During flight, the transceiver is used to transmit position, altitude, orientation or other information to a base location. The base location may be located on the ground, in the deploying airplane, or other location. The information from the flight controller may be used to monitor operation of the system in real-time. Additionally, the transceiver may receive information from the base location. Such information may include manual override control of the system or change in target coordinates. [0018] According to another aspect of the invention the steering and release actuators are pneumatic, being powered by compressed gas instead of battery power. Miniature carbon fiber high pressure compressed gas tanks can store far more power density than cold weather batteries and are unaffected by extreme cold. BRIEF DESCRIPTION OF THE DRAWINGS [0019] FIG. 1 is a side view of a parachute system according to an embodiment of the present invention. [0020] FIG. 2 is a top view of the parachute system of FIG. 1 . [0021] FIG. 3 is a flow diagram for operation of a parachute system according to an embodiment of the present invention [0022] FIGS. 4 A-G illustrate the sequence of operation of a parachute system according to an embodiment of the present invention. [0023] FIG. 5 is a top view of a flight controller according to an embodiment of the present invention. [0024] FIG. 6 is a block diagram of the components of the flight controller. DETAILED DESCRIPTION [0025] In order to provide improved performance for automatic control of cargo drops, the parachute system of the present invention includes multiple parachutes and a flight controller. FIGS. 1 and 2 are respectively a side view and a top view of an embodiment of the parachute system 10 of the present invention when packed for deployment. The parachute system includes a drogue 20 , a high wing loaded, guidance parachute or wing 30 , and a landing parachute 40 . Preferably, the guidance parachute is a high wing loaded, high speed, steerable, ram air parachute. However, any controllable wing or parachute may be used. Preferably, the landing parachute is a larger parachute allowing slow unguided vertical descent. A flight controller 50 is disposed below the parachutes and operates to control deployment of the parachutes and steering of the guidance parachute. The parachutes 20 , 30 , 40 may be of any known design based upon the type of chute required for the specific operation. [0026] FIG. 3 is a block diagram illustrating the operation of the parachute system 10 under control of the flight controller 50 . Illustrations relating to the sequence of operation of the parachute system 10 are illustrated in FIGS. 4A-4G . As illustrated in FIG. 4A , the parachute system 10 is attached closely to the cargo 70 to prevent movement in the cargo hold of the plane. FIG. 4A illustrates the cargo 40 as a barrel, but any other type of cargo container, including pallets, could be used. The orientation of the parachute system and the mechanisms for attachment to the cargo will depend upon the type of cargo being dropped. [0027] To start the cargo drop process, illustrated in FIG. 3 , the cargo and parachute system are deployed in a known manner from the delivery aircraft at step 110 . Preferably, a static line deployment is used. Upon deployment of the cargo and parachute system, the drogue 20 is deployed (step 120 ; FIG. 4B ), preferably using a static line 21 ( FIG. 1 ). Of course, other mechanisms could be used to deploy the drogue, including a controllable release operable from by the flight controller 50 . The drogue properly orients the cargo with the parachute system 10 on top and releases the tie downs 25 . [0028] During the delivery flight and upon discharge of the cargo, the parachute system 10 is tightly retained against the cargo 70 . However, for improved flight, the cargo 70 is preferably suspended below and away from the parachute system 10 via a swivel. Thus, at step 130 , the drogue chute releases tie downs 25 between the parachute system 10 and the cargo 70 . Preferably, the parachute system is closely attached to the cargo using 3-ring releases. Cable 24 ( FIG. 4B ) from the drogue bridal to the 3-ring releases allows the cargo to separate from the parachute system upon deployment of the drogue. Following release of the tie downs 25 , the cargo 70 is attached to the parachute system 10 with a harness 71 . The harness 71 allows the cargo to hang from the parachute system 10 . Any type of harness 71 can be used to retain a proper orientation of the cargo below the parachute system 10 . Preferably, a swivel 72 is included in the harness 71 to allow for spurious movement of the cargo from winds during descent. The parachute system 10 of the present invention is not limited to any particular tie down 25 or harness 71 . Furthermore, the parachute system 10 could be directly attached to the cargo 70 with out the need for the separation in step 130 . [0029] According to an embodiment of the present invention, at step 140 , an inventive hydraulic time delay is introduced for the drogue 20 . Tension on the drogue bridal is applied to a piston in hydraulic fluid. The piston has an orifice drilled through it to allow passage of fluid from one side of the piston to the other. As fluid is incompressible the flow can not go supersonic and the speed the piston can move is able to be fixed. The motion of the piston is transferred to a cable that initiates the guidance wing deployment at the end of its stroke. The purpose of the time delay is to ensure the system is in stable drogue fall before deploying the guidance parachute 30 . The delay may also be controlled by the flight controller via an actuator (not shown). Alternatively, a double bag system could be used for the guidance parachute instead of the drogue delay. [0030] Following the drogue delay, the guidance parachute 30 is deployed (step 150 ; FIG. 4D ). As illustrated in FIG. 2 , the guidance parachute is retained in a multiple flap container 31 prior to deployment. Following the delay, the release cable 23 is pulled which opens the bag 31 . According to an embodiment of the invention, the release cable 23 removes a pin from a string holding the flaps of the multiple flap container 31 closed. The string also retains riser extensions 65 , 66 , 67 , 68 at the bridal 22 . The riser extensions 65 , 66 , 67 , 68 are connected to the harness/container system 10 to carry the weight of the system and cargo and relieve stresses on the fabric of the harness/container system during use of the drogue. The drogue bridal 22 is attached to the guidance parachute bag 30 causing it to be deployed when the container 31 is released. Alternatively, the release cable 23 could be operated by the flight controller 50 . [0031] The guidance parachute 30 is preferably of a type having high wing load and high speed. According to an embodiment of the invention, the guidance parachute is preferably wing loaded in the range of five to twenty (5-20) pounds per square foot wing loading, and has forward flight speeds of forty to one hundred forty (40 to 140) miles per hour. An exception to such performance characteristics may to be when the system is used with extremely small payload, i.e., seventy-five (75) pounds. With small payloads, further reducing the size of the parachute becomes impractical. Lightweight systems may fly at lower wing loadings. Current systems of the invention have been tested from four and one half to ten (4.5-10) pounds per square foot loading. [0032] The guidance parachute 30 is connected via four risers 61 , 62 , 63 , 64 attached to the harness/container system 10 . The four risers 61 , 62 , 63 , 64 extend from the suspension harness 71 , and preferably from the swivel 72 to the parachute system 10 . The webbing from the swivel are sewn to the sides of the container of the parachute system. Each riser includes a 3-ring release 61 a , 62 a , 63 a , 64 a between the container system and the guidance parachute. Before deployment of the guidance parachute, the risers 61 , 62 , 63 , 64 extend into the multiple flap bag 31 through the corners. Upon deployment, the risers suspend the parachute system 10 and the cargo 70 from the guidance parachute 30 . [0033] Brake lines 81 , 82 are connected to the guidance parachute 30 for control. The brake lines 81 , 82 are retained in sleeves 81 a , 82 a attached to the risers 61 , 64 , and extend into the parachute system for attachment to the steering actuators. The steering actuators are operated by the flight controller 50 to steer the canopy 30 in a known manner. The steering actuators are preferably pneumatic and built as an integrated steering module possessing multiple functions. Pneumatically controlled stages can transverse linearly to pull either the left or right control line. The lines are each routed through a pneumatic guillotine cutter which allows the line connection to the actuator to be severed when transitioning from the guidance parachute to the landing parachute. Additionally, many ram air parachutes deploy best when the brake lines are partially pulled during deployment. The force required to hold the brake lines during deployment is typically many times the force required to actuate a turn once in flight. As such, so as not to over design the strength of the steering actuators, an additional pneumatic actuator is provided to pull a pin for each line. There is a loop on each brake line that can be set or trapped by the actuation prior to retracting the pin. The pin allows a very high holding force on the brake lines during deployment and then is retracted freeing the brake lines to be controlled by the steering actuators. [0034] At step 160 , the flight controller adjusts the direction of the guidance parachute 30 using the brake lines 81 , 82 to direct the cargo towards the desired target location. Operation of the flight controller 50 for steering the guidance parachute is discussed below. [0035] Once the cargo 70 and parachute system 10 reaches an area approximately overhead of the desired target location, the guidance parachute is controlled to fly in a spiral dive or holding pattern (step 170 ; FIG. 4E ). Other holding patterns, such as a figure- 8 or flat spiral (slow altitude drop maneuver), could also be used. A spiral will initiate the fastest possible vertical decent. Tested systems with a wing load of four and one half (4.5) have shown a vertical decent rate in a spiral dive of 120 mph. The cargo 70 and parachute system 10 descends without significant variation from the target location. If the flight computer detects significant drift it will stop the spiral correct and reinitiate, if time permits once corrected. and parachute system 10 reaches an area approximately overhead of the desired target location, the guidance parachute is controlled to fly in a spiral dive or holding pattern (step 170 ; FIG. 4E ). Other holding patterns, such as a figure- 8 or flat spiral (slow altitude drop maneuver), could also be used. A spiral will initiate the fastest possible vertical decent. Tested systems with a wing load of four and one half (4.5) have shown a vertical decent rate in a spiral dive of one hundred twenty (120) mph. The cargo 70 and parachute system 10 descends without significant variation from the target location. If the flight computer detects significant drift it will stop the spiral correct and reinitiate, if time permits once corrected. [0036] Prior to the system spiraling into the ground, at a minimum altitude preset into the flight computer, actuators pull cables from the four 3-ring releases on the guidance parachute risers to release the guidance parachute 30 . At the same time the guillotine cutters sever the brake lines to the steering actuators. A line (not shown) connects at least one of the risers from guidance parachute 30 to a release on a multi flap container 41 containing the landing parachute. This line further attaches the guidance parachute 30 to the landing parachute 40 so its drag extracts and deploys the landing parachute. Additionally by remaining tethered, nothing is lost. The guidance parachute 30 , thus, operates as a drogue for the landing parachute 40 . The landing parachute, preferably a round canopy parachute, allows the cargo to slowly descend, landing unguided. The landing parachute should be released at a low enough altitude to prevent significant deviations from wind drift. Risers 42 for the landing parachute are sewn on the inside of the bag to the risers 61 , 62 , 63 , 64 on the outside of the bag. Upon deployment of the landing parachute, the parachute system maintains the same orientation due to the consistent placement of the risers. [0037] Militaries are content to use round parachutes from low altitudes, i.e., one thousand (1000)-[[′]] feet. Drift from such a low altitude is easy to correct and accuracy is high. This invention simply seeks to create a system to transport cargo from a high altitude plane out of harms way as rapidly as possible to a targeted low altitude for subsequent landing under a conventional round cargo parachute. [0038] FIG. 5 is a top view of components of the flight controller according to an embodiment of the present invention. FIG. 6 is a block diagram of the components of the flight controller. While specific components are illustrated and discussed herein, the flight controller may be designed in any manner to provide the desired functions and operations. Preferably, the flight controller 50 includes a microprocessor 200 and associated memory 250 . The instructions for operation of the microprocessor 200 are stored in the memory. They may be created and operated in any known computer programming language. The microprocessor 200 is programmed to provide the steps set forth in FIG. 3 . [0039] Attached to or integrated with the microprocessor 200 are other devices to provide inputs to or outputs from the microprocessor 200 for operation of the parachute system. In particular, the flight controller 50 may include a Global Positioning Satellite (GPS) system receiver 210 , a barometric altimeter sensor 220 , inertial sensors 221 , a decent arming switch 222 , or other sensors 225 , integrated with the microprocessor 200 as a single unit. Alternatively, discrete sensors may be used to provide inputs to the microprocessor 200 . The microprocessor 200 uses information from the integrated or discrete sensors to determine the position of the parachute system 10 . The altitude is provided based on a three dimensional GPS fix using the GPS receiver 210 . However, an additional barometric pressure sensor 220 may be used for redundancy. Other sensors may include inertial navigation or gyros 221 for determining position in the event that GPS signals are lost or jammed. [0040] The microprocessor 200 uses the information from the sensors to determine position and to control the parachute system 10 . The microprocessor 200 has outputs connected to electro pneumatic solenoids 240 for controlling pneumatic actuators 230 , 241 , 242 , 243 . The pneumatic actuators are powered by a source of compressed gas 235 , preferably compressed nitrogen or dry air. Alternatively, electric motors could be used instead of the actuators. However, the use of pneumatic actuators with compressed gas is advantageous for the parachute system of the present invention. The extremely cold air at the high altitudes at which the parachute system is deployed would greatly drain a battery or other source of electric power. By using the pneumatic actuators, the electrical requirements of the system for operating the microprocessor 200 is very low and system weight is reduced. [0041] The embodiment of the present invention uses two principal types of actuators: steering control actuators 240 and guidance wing release actuators 230 . Other actuators could be included to provide additional functionality. For example, the flight controller 50 could be used to deploy the drogue or to deploy the glide parachute. If the flight controller performs these functions, additional actuators and solenoids would be necessary. [0042] The steering control actuators 241 , 242 , 243 operate the brake lines 81 , 82 of the glide parachute 30 to direct the parachute system to the target location. Upon deployment of the guidance parachute 30 , the brake lines 81 , 82 must be held in for proper inflation and stabilization. A pair of deployment actuators 242 , 243 are used to hold the brake lines in. Loops in the brake lines 81 , 82 are held by the deployment actuators 242 , 243 . Once the guidance parachute is deployed and stabilized, the deployment actuators 242 , 243 release the loops and the brake lines 81 , 82 are positioned for normal operation. The brake lines 81 , 82 are controlled by steering actuators 241 , which may include one actuator 241 a , 241 b for each line. The actuators 241 pull or release the brake lines to alter the direction of flight of the system. Upon release of the guidance parachute 30 , the brake lines also need to be released. Actuators 236 , 237 are used for this purpose. Actuators 236 , 237 are positioned around the brake lines 81 , 82 at the entrance to the steering actuators 241 . Actuators 236 , 237 operate guillotine cutters to cut the brake lines 81 , 82 for release. Other combinations of actuators are possible for control of the brake lines. The steering actuators 241 may be used to hold in the brake lines during deployment rather than the deployment actuators. Other kinds of release mechanisms may also be used instead of the guillotine cutters. [0043] Four release actuators 231 , 232 , 233 , 234 are used to release the risers 61 , 62 , 63 , 64 holding the glide parachute 30 to the parachute system 10 . Each of the release actuators 231 , 232 , 233 , 234 is connected to one of the release cables 61 b , 62 b , 63 b , 64 b for the 3-ring releases on the risers. When the glide parachute is to be released, the microprocessor 200 operates the release actuators 231 , 232 , 233 , 234 to pull the release cables 61 b , 62 b , 63 b , 64 b . Alternative methods, including guillotine cutters could be used to release the risers 61 , 62 , 63 , 64 under control of the microprocessor 200 . [0044] The flight controller 50 may be powered and operated at any time during the deployment process depending upon when it is needed. According to an embodiment of the invention, the flight controller 50 is powered prior to deployment from the drop plane to allow a GPS fix to be obtained before dropping. Software ‘arming’ of the system is possible by detecting the vertical decent rate. However, a steeply diving airplane can falsely arm the system and then the units would begin steering and possible release actuators while the system is still in the cargo bay. A preferred method uses an arming switch that senses when the guidance parachute has left the container. This has been accomplished by use of a magnet sewn into the parachute bag and a magnetic reed switch connected to the flight computer. [0045] Once the guidance parachute 30 is released, the microprocessor 200 operates to control the direction of flight. The GPS receiver 210 provides position information which is also used to determine orientation. The microprocessor 200 provides signals to the steering control actuators 241 attached to the brake lines 81 , 82 of the guidance parachute 30 to steer the system. The target location is stored in memory 250 . The system determines the necessary changes in flight direction to move from the currently traveled vector to one that would intersect overhead of the target. Preferably, the system uses PID control algorithms to prevent oversteering when correcting the flight vector. Such oversteering results in a system that flys a sinewave or damped sinewave flight path instead of perfectly straight. [0046] Once the target location has been reached, as determined by the microprocessor 200 , the microprocessor 200 actuates [a] steering actuators 241 to initiate a sustained turn or spiral dive or other holding pattern. The cargo and parachute system continues to descend over the target location. Once a set altitude is reached, as stored in the memory 250 , as determined by the altimeter 220 or the GPS receiver 210 , the microprocessor 200 sends a signal to the guidance wing release actuators 230 to release the risers 61 , 62 , 63 , 64 of the guidance parachute 30 and sever the brake lines, thus deploying the landing parachute. The system continues it descent using the landing parachute until touchdown. [0047] The flight controller 50 needs to be programmed with the target location and altitude information for the landing parachute release. Input/output (I/O) ports are attached to the microprocessor 220 for the purpose of inputting the necessary information. The I/O ports may be of any known type, and may include a display, keyboard, mouse, disk or other memory drive, or a port for connection to a computer or other storage device. FIG. 6 illustrates a wireless modem 260 and antenna 261 as an I/O port for inputting information. Additionally, if appropriate, the drogue delay time may also be entered into the system using the I/O ports. [0048] When the glide ratio of the system is known, the flight computer may be connected to an indicator light to show when the drop plane is within the cone of acceptability to drop the cargo and have it fly to its intended target. This aids drop personnel in the cargo plane. [0049] Since the microprocessor 200 of the flight controller 50 is receiving information about the flight, such as position and altitude, the information can be stored in the memory 250 . A timer (not shown) can be used to provide time based information in the memory 250 . Upon completion of the drop, the stored information from the memory 250 can be retrieved through the I/O ports for analysis and review. Other sensors could also be included in the flight controller 50 for determining and recording data for analysis. For example, sensors could be used to determine G-forces, stress and strain placed on various components of the parachute and the cargo. These sensors can be connected to the microprocessor 200 to store the sensed information in the memory. [0050] The flight controller 50 may also include a transceiver for wireless communication with the flight controller. The wireless modem 260 and antenna 261 illustrated in FIG. 6 can also function as a transceiver. The transceiver is preferably RF, but can include an infrared or other transmission medium. The transceiver can be used to output position, altitude or other information, in real time to a base station. The base station may be in the delivery aircraft, at the target location, or some other control position. The information transferred from the flight controller 50 to the base station can be used to monitor flight and operation of the system. Additionally, the transceiver can be used to receive information from the base station. The base station could transfer information changing any of the flight parameters, such as the target location. Alternatively, direction information could be transmitted to the flight controller for the steering controller 240 . Thus, the parachute system could be remote controlled by an operator at the base station, instead of automatic operation. In a preferred embodiment telemetry data sent to the base station is graphically displayed on a screen to allow remote control without visual contact with the parachute system. [0051] A GPS repeater provides the GPS signals within the cargo area of the aircraft. Thus, the GPS receiver of the flight controller can acquire a position lock prior to being dropped. The flight controller must be powered on several minutes before drop to allow a valid ephemeris to be downloaded which can take up to four (4) minutes. If they are then shut off, the software directs them to look for GPS satellites as if they were in the same position from time of power off. With the inventive system, it has been found that up to two (2) hours ‘black out’ period results in a reacquisition of position lock in forty (40) ms to eight (8) sec, after two (2) hours extending out to four (4) hours the time lengthens to its maximum of up to four (4) minutes. [0052] FIG. 3 illustrates the steps for operation of the flight controller after launch of cargo and parachute system from the delivery aircraft. The flight controller would also include a program for operation in a pre-launch mode to prepare for launch. The pre-launch mode include the steps of uploading target coordinates through the I/O ports and downloading a valid ephemeris for the drop location to the GPS receiver. Target coordinates on the inventive system may be uploaded by an RS232 or other connection from a laptop or dedicated handheld terminal, or simply by inserting a memory chip with the data into the flight computer, i.e. a compact flash card is uploaded with target data from the laptop software and then inserted into the flight computer. The ephemeris is automatically acquired by the GPS. [0053] In another embodiment, the parachute system of the present invention is used to convert dumb bomb to guided ‘smart’ bombs. Militaries have been converting inexpensive ‘dumb’ bombs into more effective guided weapons by a bolt on tail kit that includes a guidance computer/sensors/software and actuators for piloting the tail fins of the bomb, i.e., JDAM/conversion. These devices have received extensive use in the Gulf War and in Afghanistan. Cost wise they are very desirable, but performance wise they have certain shortcomings. The bombs typically weigh from five hundred to two thousand (500-2000) pounds. The tail fins are an extremely small wing surface for guiding such a heavy weight; as such, they are not capable of much course correction or significant glides. They suffer from accuracy and standoff shortcomings. A parachute system of the present invention attached to a dumb bomb, typically at the tail, to create a bomb guided by a high performance guidance parachute overcomes the problems of limited standoff and accuracy while remaining economically competitive. The coordinates of the desired target are loaded into the system. Since the bomb is intended to explode at impact, the landing parachute can be eliminated. Soft landing required for cargo is not required for bombs. Thus, step 180 in FIG. 3 can be eliminated allowing the system to fly under the high speed, high wing load guidance wing until impact with the target or triggered to detonate at a predetermined distance above the target. [0054] While the present inventions have been described with a certain degree of particularity, it is obvious from the foregoing detailed description that one skilled in the art may make one or more modifications which are suggested by the above descriptions of the novel embodiments.

An autonomous guided parachute system for cargo drops that divides the requirements of guidance and soft landing into separate parachutes. Said invention includes a high wing-loaded ram air parachute for guidance, a larger round parachute for soft landing, a harness/container system, flight computer, position sensors and actuation system. The system is dropped from an airplane. A predetermined period of drogue fall ensures a stable position prior to deploying the guidance parachute. The flight controller determines a heading to intersect with an area substantially above the desired target and controls the guidance parachute via pneumatic actuators connected to the parachutes steering lines to fly on that heading. At a minimum altitude prior to the system's impact with the ground the flight computer transitions the system from the fast high performance guidance parachute to a larger landing parachute by releasing the guidance parachute to static line extract and deploy the landing parachute. If the system reaches a position substantially above target area prior to the parachute transition altitude the flight computer controls the system into a spiral dive or other rapid altitude dropping maneuver until the transition altitude is reached. Once transitioned to the landing parachute the system descends for a brief period unguided under the landing parachute until touchdown.

CROSS REFERENCE TO RELATED APPLICATION Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 13/031,347, filed concurrently herewith, entitled: “Method for Media Reliving Playback”, by Jiebo Luo et al., which is incorporated herein by reference. FIELD OF THE INVENTION The present invention relates generally to sharing photo and video collections, and particularly to a time-varying presentation of photos and videos in response to real-time user requests. BACKGROUND OF THE INVENTION Pictures and videos are not taken only to record memory. There is an increasing recognition and emphasis on a media sharing and rich reliving experience. There have been many attempts to enable and empower media sharing and browsing. Popular commercial photo and video management systems have recently started to leverage spatial, temporal, and social cues for image and video organization and browsing. For example, Apple iPhoto and Google Picasa extract global positioning system (GPS) information whenever available and display photos and videos on a map. Although with iPhoto users can configure events that will serve as their basic browsing units, Google Picasa permits users to choose from a flat list view (using years as separators) and a tree view of their pictures. One of the prized additions to both Apple iPhoto and Google Picasa is the ability to detect, extract, group and label faces with a certain amount of user interaction. With respect to browsing, both iPhoto and Picasa permit individual browsing as well as a slide-show option. In addition iPhoto has a skimming option wherein a user can mouse-over an event causing the thumbnail to cycle through the contents of the particular event. Both iPhoto and Picasa permit picture and video tagging and geo-tagging. As an alternative way of browsing Google has proposed Swirl that enables hierarchical browsing of collections. Images are clustered by appearance and content into groups hierarchically. There is an inherent “intent gap” in providing a browsing or reliving experience to different receivers because it is difficult for current computer systems to know what each receiver likes to see. There is also a practical “semantic gap” in using current computer systems to analyze the semantic content of the images or videos in a media collection. Another aspect that has not been recognized or addressed by the current systems mentioned above is the need to consider the receiver's need in one's diverse social networks that contain busy people always on the run with different interests. SUMMARY OF THE INVENTION The present invention represents a method for viewing a collection of images or videos, comprising: (a) analyzing the collection to determine properties of the images or videos and using the determined properties to produce icons corresponding to such properties; (b) providing a time-varying display of the images or videos in the collection following an ordering of the images or videos in the collection and at least one of the corresponding icons; (c) receiving a user selection of an icon; and (d) changing the time-varying display of the images or videos in the collection following a reordering of the images or videos in the collection in response to the user selection. It is an advantage of the present invention to redefine sharing and reliving as a function of the receiving person's needs in an attempt to overcome both “semantic gap” and “intent gap” by including a user in the loop. A plurality of robust semantic understanding technologies are selected to facilitate author-based story-telling as well as receiver-based customization. An advantage of the present invention is to provide a receiver the ability to redirect the flow of the media reliving experience along multiple dimensions at will. In contrast, alternatives are standard slideshows, or a system that requires users to provide labor intensive media annotation for this same purpose. It has the additional advantage that reliving are achieved using a plurality of intuitive dimensions reliably extracted from photo and video content and meta-data. In the present invention, the three dimensions of who-when-where serve as axes or guides for viewers to relive using photo and video collections. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a system that will be used to practice an embodiment of the present invention; FIG. 2 is a pictorial illustration of an interface of the present invention; FIG. 3 is a block diagram of steps involved in the media processing component of the present invention; FIG. 4 is a flow diagram illustrating steps of operations of the present invention; FIG. 5 is a block diagram showing a plurality of media metadata used in the present invention; FIG. 6 is a block diagram showing a plurality of event metadata used in the present invention; FIG. 7 is a block diagram showing operation steps involved in the media reliving experience component of the present invention; FIG. 8 is a pictorial illustration of example page layouts according to the present invention; and FIG. 9 is a block diagram showing transforms needed for transition from one photo to another photo according to faces in the photos. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates a system 100 for media reliving and browsing, according to an embodiment of the present invention. The system 100 includes a data processing system 110 , a peripheral system 120 , a user interface system 130 , and a processor-accessible memory system 140 . The processor-accessible memory system 140 , the peripheral system 120 , and the user interface system 130 are communicatively connected to the data processing system 110 . The data processing system 110 includes one or more data processing devices that implement the processes of the various embodiments of the present invention, including the example process of FIG. 2 . The phrases “data processing device” or “data processor” are intended to include any data processing device, such as a central processing unit (“CPU”), a desktop computer, a laptop computer, a mainframe computer, a personal digital assistant, a Blackberry™, a digital camera, a cellular phone, or any other device or component thereof for processing data, managing data, or handling data, whether implemented with electrical, magnetic, optical, biological components, or otherwise. The processor-accessible memory system 140 includes one or more processor-accessible memories configured to store information, including the information needed to execute the processes of the various embodiments of the present invention. The processor-accessible memory system 140 is a distributed processor-accessible memory system including multiple processor-accessible memories communicatively connected to the data processing system 110 via a plurality of computers or devices. On the other hand, the processor-accessible memory system 140 need not be a distributed processor-accessible memory system and, consequently, can include one or more processor-accessible memories located within a single data processor or device. The phrase “processor-accessible memory” is intended to include any processor-accessible data storage device, whether volatile or nonvolatile, electronic, magnetic, optical, or otherwise, including but not limited to, registers, floppy disks, hard disks, Compact Discs, DVDs, flash memories, ROMs, and RAMs. The phrase “communicatively connected” is intended to include any type of connection, whether wired or wireless, between devices, data processors, or programs in which data is communicated. Further, the phrase “communicatively connected” is intended to include a connection between devices or programs within a single data processor, a connection between devices or programs located in different data processors, and a connection between devices not located in data processors. In this regard, although the processor-accessible memory system 140 is shown separately from the data processing system 110 , one skilled in the art will appreciate that the processor-accessible memory system 140 is stored completely or partially within the data processing system 110 . Further in this regard, although the peripheral system 120 and the user interface system 130 are shown separately from the data processing system 110 , one skilled in the art will appreciate that one or both of such systems are stored completely or partially within the data processing system 110 . The peripheral system 120 can include one or more devices configured to provide digital images to the data processing system 110 . For example, the peripheral system 120 can include digital video cameras, cellular phones, regular digital cameras, or other data processors. The data processing system 110 , upon receipt of digital content records from a device in the peripheral system 120 , can store such digital content records in the processor-accessible memory system 140 . The user interface system 130 can include a mouse, a keyboard, another computer, or any device or combination of devices from which data is input to the data processing system 110 . In this regard, although the peripheral system 120 is shown separately from the user interface system 130 , the peripheral system 120 is included as part of the user interface system 130 . The user interface system 130 also can include a display device, an audio output device such as speakers, a processor-accessible memory, or any device or combination of devices to which data is output by the data processing system 110 . In this regard, if the user interface system 130 includes a processor-accessible memory, such memory are part of the processor-accessible \memory system 140 even though the user interface system 130 and the processor-accessible memory system 140 are shown separately in FIG. 1 . The present invention builds an automatic system using the above mentioned processor to address the photo sharing problem mentioned in the background section, i.e., organizing individual collections of images or videos captured for the same event by different cameras into a master collection. The phrase, “digital content record”, as used herein, refers to any digital content record, such as a digital still image, a digital audio file, or a digital video file, or a frame of a digital video. The phrase, “media stream”, as used herein, refers to any sequence of a plurality of digital content records, such as digital still images, digital audio files or digital video files. Referring to FIG. 2 , there is shown a pictorial illustration of an interface of the present invention. One or more images or videos are displayed in a center media display area 200 of the display. A plurality of navigation tool bars are provided to enable a viewer to redirect the flow of the time varying display of images or videos, including a “places” navigation tool bar 201 , a “people” navigation tool bar 202 , a “time” navigation tool bar 203 , and an “event” navigation tool bar 204 . Each navigation tool bar 201 , 202 , 203 , 204 can contain zero, one, or multiple icons indicating what options are available to the viewer for that tool bar. For example, multiple maps are shown to indicate to the viewer the places where images or videos have been taken, multiple face images are shown to indicate the people who are present in the images or videos in the media collection, multiple bars of various heights are shown to indicate the years and months when images or videos have been taken, and multiple thumbnail images are shown to indicate multiple events that are related to the viewers current request. FIG. 3 shows the building components of the present invention and their interaction. Media collection 1000 is a media collection of pictures or videos from personal, family, or friends' sources. Metadata repository 1002 is a database repository of descriptive metadata, or properties, obtained from the media collection 1000 . In an embodiment of the present invention, properties including “places”, “people”, “time”, and “events” are examples of the metadata in the metadata repository 1002 . They are presented as icons on the corresponding navigation tool bars 201 , 202 , 203 , 204 . A media processing component 1003 , a process of producing metadata from the media collection 1000 , is described in more detail in FIG. 4 . A reliving experience component 1008 involves a combination component 1004 of media collection 1000 , metadata repository 1002 , and a user interaction component 1006 . The media collection 1000 is displayed in a time-varying fashion to the user although the metadata repository 1002 and user interaction component 1006 drive the reliving experience component 1008 . FIG. 4 shows the steps involved in the media processing 1003 component that extracts metadata. Step 1010 involves date and time extraction from every image or video in the media collection 1000 . Images or videos taken with digital cameras or camcorders typically have date and time information embedded in their file headers that are extracted. The date and time information from the entire collection is used to perform event clustering 1018 . In the present invention, events are the basic units of user reliving experience. Semantically images or videos in an event are related in their content by time, place, people, or some combination of them. The present invention performs event-clustering based on visual and temporal information as described in U.S. Pat. No. 6,606,411 to Loui et al, entitled “Method for automatically classifying images into events”. Briefly summarized, a collection of images is classified into one or more events determining one or more largest time differences of the collection of images based on time or date clustering of the images and separating the plurality of images into the events based on having one or more boundaries between events where one or more boundaries correspond to the one or more largest time differences. For each event, sub-events are determined (if any) by comparing the color histogram information of successive images. The time, date, and event cluster information for media is stored in the metadata repository 1002 . For each image or video in the media collection 1000 , an aesthetic value or quality is computed in Step 1012 and stored in the metadata repository 1002 . Aesthetic value or quality is a valuable determinant in deciding how much screen-time and how much in size and how prominent in position should be allotted to an image or video during the reliving experience component 1008 . In an embodiment of the present invention, an image value index is computed for each image or video using a method described by Jiang, Loui, and Cerosaletti, “Automatic aesthetic value assessment in photographic images,” in the proceedings of the 2010 IEEE International Conference on Multimedia and Expo (ICME). Another important metadata extracted from media collection 1000 is information about people present in images or videos. In order to achieve this, the present invention performs a face detection step 1014 . Face detection has been a very active research area in computer vision for several decades now. A method to detect faces in pictures is described within an object detection framework in the published article of Paul Viola and Michael Jones, “Rapid Object Detection using a Boosted Cascade of Simple Features”, Proceedings of the International Conference on Computer Vision and Pattern Recognition, 2001. A preferred embodiment of the present invention uses the face detection method described in the above article for step 1014 . The faces detected are used to perform face clustering in step 1020 . The objective of this step is to group similar looking faces that belong to the same individual into one cluster to facilitate subsequent viewing if a viewer chooses to browse or relive images or videos of a particular individual. A face recognition step 1022 attaches specific name labels to face clusters identified in step 1020 . This is performed by manual labeling of names with the help of a user (familiar with people in the collection) or by automatic methods based on machine learning such as described in the published article of He, Yan, Hu, Niyogi and Zhang, “Face recognition using Laplacianfaces”, IEEE Transactions on Pattern Analysis and Machine Intelligence, 27(3), 2005. The present invention adopts the former approach for face recognition and labeling by proving a user-interface that permits a user to associate labels with faces that have been clustered for different individuals. Face labels and cluster information are stored in the metadata repository 1002 . Geographic location, if available with images or video, can provide another form of metadata helpful for media reliving. The geographic location of an image or video are in the form of latitude-longitude pair (recorded automatically at capture time or later manually by user placement of media on a geographic map) or in the form of descriptive country/city place names (provided by user). The location information extraction step 1016 extracts location information from images or videos whenever such information is available. A geographic clustering step 1024 is then performed to group closely taken (in location) images or video together. The present invention uses a mean-shift clustering based approach as described in the published article of Cao, Luo, Gallagher, Jin, Han, Huang, “A Worldwide Tourism Recommendation System Based on Geotagged Web Photos”, Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, 2010. In another embodiment of the present invention, descriptive country/city place names are extracted from user provided information (e.g., in the image file names, image folder names, or other image related tags). The location and geographic cluster information obtained from the media collection is stored in metadata repository 1002 . FIG. 5 depicts examples of media metadata that is related to each image or video 1100 . In a preferred embodiment of the present invention, they fall into three categories including semantic media metadata 1101 (time, geographic location, people), generic media metadata 1102 (type, URL, height-width), and aesthetic value metadata 1104 (aesthetic value). FIG. 6 depicts examples of event metadata that is related to each event 1500 that contain one or more images or videos. Recall that events are the basic units of user reliving experience in the present invention. In a preferred embodiment of the present invention, they fall into two categories including a media list 1501 (a list of images or videos in an event), and semantic event metadata 1502 (people list, geographic location, [start-time, end-time]). FIG. 7 shows a block diagram of the operation steps involved in the media reliving experience component 1008 ( FIG. 3 ) of the present invention. The present invention provides a user several criteria to control the reliving experience. In an embodiment of the present invention, the criteria correspond to ‘time’, ‘location’, ‘people’, and ‘event’. For each criterion, a set of clickable icons are shown to the user to help make their choice. The ‘time’ criterion is displayed as bars for years and months (where the bar height corresponds to image or video capturing activity in the corresponding month or year). The ‘location’ criterion is displayed in the form of geographic clusters obtained in step 1024 ( FIG. 4 ) during which the ‘people’ criterion is displayed as labeled faces from the collection (step 1022 in FIG. 4 ). A user-click on a particular icon triggers a reordering of the images or videos in the collection to honor the user selection (steps 2000 and 2004 in FIG. 7 ). If the user chooses not to click on any criterion but to passively experience the reliving show, a default order of events is used by the present invention (step 2002 ), or the current order of events is played out until further user actions. Each event 2006 in the event list contains corresponding images or videos, which will be displayed in a time-varying fashion with proper selection of layout, transition effect, suitability, and music in steps 2008 - 2014 . In the present invention, the reordering for the time criterion occurs based on the normalized time span difference between the user selected time stamp and start time of each event (which contains images or videos). The method selected for location based reordering is based on the normalized spatial difference between user-chosen-location and location of an event. For the ‘people’ criterion, the suitability of each event is computed based on a weighted average of the percentage of images that contain the person selected by the user, and the actual number of images with the person's face. Hence after sorting, events with many images of that person (both in ratio and absolute terms) show up at the top of the event tool bar. This order of events computed in step 2004 dictate the order in which events are presented to the user. Alternatively, in step 2002 , the order of events is computed with time selected as the default criterion. Each event contains images or video and presentation of an event corresponds to presentation of images or video in some fashion. The present invention computes a suitability score for each image or video in any given event (step 2012 ). This suitability score depends on the user selected criteria for reliving. If the criterion selected is ‘time’, or ‘location’, the present invention uses the aesthetics value (computed at step 1012 in FIG. 4 ) to score the image. If the criteria selected is ‘person’ (or a group of persons if the user chooses more than one person), a weighted average of multiple factors is computed as the suitability score wherein the factors include: chosen person's presence in the image or video, the relative size of the face in the image or video, the location of the face, the ratio of chosen person(s) to total number of persons present in that image. In another embodiment of the present invention, a pruning step is adopted to discard images that score below a threshold. This is useful to ensure that only images of the person selected (in person criteria) are displayed and getting rid of very poor quality images in other criteria. Otherwise, images or videos would be displayed in a descending order of the current user selected criterion without further user intervention. Step 2008 performs layout selection for the media to be displayed. Ideally the layout should be aesthetically pleasing and relevant to show the media (images or video) in a given event. In an embodiment of the present invention, page layouts with two ( 3000 ), three ( 3002 ), four ( 3004 ) or five ( 3006 ) images are pre-designed, as shown in FIG. 8 . For a given event, a layout is selected such that the number of images or video shown is a direct multiple of the total number of images or videos in the event. If the number of images or videos in an event is greater than the number of images or videos permitted by a layout selected at step 2008 , they cannot be displayed in one step. The present invention provides for a dynamic transition between outgoing and incoming images of videos. Step 2010 performs transition selection for the media to be displayed. In the present invention, the transitions for ‘time’ and ‘location’ criteria are ‘slide in’ and ‘slide out’ of the screen. For the ‘people’ criteria, the present invention performs a semantically more meaningful transition that provides the effect of the person's face being used as a ‘wormhole’ to move on from one image or video to another. As shown in FIG. 9 , an affine transformation (rotation, translation, and scale) is computed to move the face in the current image or video 4000 into a predefined size-orientation intermediate frame 4002 . At the same time a transformation to move from the intermediate frame 4002 according to the face in the next image 4004 is also computed. When both these transformations are applied in tandem as a smooth transition, such a transition produces the abovementioned face-to-face transition effect. In the meantime, step 2014 selects semantically meaningful music to accompany the media to be displayed. The music accompanying the media is selected based on the current user criterion chosen at step 2000 that drives the time-varying display of the media. The music reflects the user criterion in content or genre. In one embodiment of the present invention, for the ‘time’ criteria, music is selected based on the season (e.g. music for seasons spring, summer, autumn, winter) of the event; for criteria ‘people’, music is selected based on generation (and gender if applicable) of the person(s) selected (e.g. music for the generation of Baby-boomers and generations X, Y, and Z); for criteria ‘location’ an embodiment of the present invention searches into a database of geolocation-characteristic songs and chooses the music that is closest of the location of the event. A database of geolocated music is constructed by manually searching for music in a location annotated music database and selecting songs for popular tourist destination locations. After computing the suitability, layout, transition, and the accompanying music for media, step 2016 displays the images or video one event at a time. The images or video are granted screen time based on their suitability score (computed at step 2012 ). In the present invention, images or video are displayed in a purely temporal order so as to present a clear temporal flow to the user who is reliving the media collection. At times, the orientation of the images or video (landscape or portrait) might not match with the screen space allotted to them (based on the layout selected in step 2008 ). In order to resolve this issue, the present invention performs auto-zoom-crop to maintain semantic content. For the criteria ‘people’, the auto-zoom-crop attempts to preserve the chosen person's face. If the criterion is not ‘people’ and images or video contain faces, auto-zoom-crop attempts to preserve faces that are found. If no faces are found in images or video, auto-zoom-crop attempts to conserve the center portion of the image by sacrificing the outer parts. In order to avoid the problem of having multiple images or video transitioning out of the screen at the same time (and leaving large blank screen space), the present invention implements a simple token passing scheme between different holes, which permits only one image or video frame/hole to be outside the screen at a given time. In step 2018 , the navigation toolbars are updated based on the content of the displayed event. In the present invention, the ‘time’ browsing toolbar remains constant and permits users to switch to any time instance, except the month or year of the current event is highlighted to give the user a sense when in time she is. The ‘people’ toolbar shows people relevant to the displayed event. The ‘location’ toolbar shows locations of nearby events. In one embodiment of the present invention, the ‘people’ and ‘location’ toolbars also contain certain slots that, if requested, are filled by people or location randomly chosen from the user collection. The rationale behind this randomization is to permit the user to take a random leap in the reliving experience if she gets bored with the current selection. The present invention also contains a toolbar which gives preview of current and next few events by showing a sample image or video of the event as a representative thumbnail and giving (mouse-over) details of the event type and number of images or video in them. The present invention also permits users to control the speed, and flow of the reliving experience at any time by adjusting the temporal display speed as well as an options to pause the slide show or go back to the previous event. The present invention also permits storing the time-varying display of images or videos in the collection in a processor accessible memory. Furthermore, the stored time-varying display of images or videos are used to produce a movie, photo pages, or a photo book. It is to be understood that the exemplary embodiments disclosed herein are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by one skilled in the art without departing from the scope of the invention. It is therefore intended that such variations be included within the scope of the following claims and their equivalents. PARTS LIST 100 System 110 Data processing system 120 Peripheral system 130 User interface system 140 Processor-accessible memory system 200 Center media display area 201 “Places” navigation tool bar 202 “People” navigation tool bar 203 “Time” navigation tool bar 204 “Event” navigation tool bar 1000 Media collection 1002 Metadata repository 1003 Media processing component 1004 Combination component 1006 User interaction component 1008 Reliving experience component 1010 Date and time extraction step 1012 Aesthetics value extraction step 1014 Face detection step 1016 Location information extraction step 1018 Event clustering step 1020 Face clustering step 1022 Face recognition step 1024 Geographic clustering step 1100 Media (an image or video) 1101 Semantic media metadata 1102 Generic media metadata 1104 Aesthetic value metadata 1500 Event 1501 Media list 1502 Semantic event metadata 2000 User selection step 2002 Use default order of events step 2004 Reorder event list according to user selected criterion step 2006 Each event in event list 2008 Select layout for media step 2010 Select transition for media step 2012 Compute suitability for media step 2014 Select music for media step 2016 Display media in event list step 2018 Update navigation toolbars 3000 Two-image page layout 3002 Three-image page layout 3004 Four-image page layout 3006 Five-image page layout 4000 Current image with a face 4002 Intermediate image with a face 4004 Next image with a face

A method for viewing a collection of images or videos, includes analyzing the collection to determine properties of the images or videos and using the determined properties to produce icons corresponding to such properties; providing a time-varying display of the images or videos in the collection following an ordering of the images or videos in the collection and at least one of the corresponding icons; receiving a user selection of an icon; and changing the display of the images or videos in the collection following a reordering of the images or videos in the collection in response to the user selection.

[0001] The present invention relates to a metallocene catalyst based on a transition metal from group 4 or 5 of the periodic table which is supported by hybrid catalyst supporting means with aliphatic organic groups. [0002] One also describes the process for supporting metallocene on said hybrid catalytic supporting means with aliphatic organic groups. [0003] The main advantage of the supported metallocene catalyst of the present invention is that an ethylene polymer with broad or bimodal molar mass distribution is produced by using only one type of metallocene complex on the supporting means. As a result, the resin produced can be processed in an improved manner, and one obtains a potential reduction of processing costs. DESCRIPTION OF THE PRIOR ART [0004] There are many researches involving the development of metallocene catalysts. These catalysts, due to the fact that they have a single active center, enable the production of polyolefins with properties that are differentiated in terms of molecular mass, molar mass distribution, stereoregularity and incorporation and co-monomer distribution. [0005] Particularly, polymers that have a narrow distribution of molar mass exhibit better physical properties, such as resistance to impact and to “environmental stress cracking”, as well as film transparency. However, these polymers exhibit processing difficulty due to their restriction in the distribution of molar mass. [0006] In general, a broad distribution of molar mass provides greater fluidity of the polymer in the molten state, facilitating the processing thereof. [0007] Thus, a few strategies for broadening the distribution of molar mass of polyolefins produced by using metallocene catalysts have been developed in the prior art. Among them we can cite: (i) blends of polymers produced by two different catalysts such as described in U.S. Pat. No. 6,649,698 and U.S. Pat. No. 6,787,608; (ii) use of multi-reactor technology as described in WO07336A1; U.S. Pat. No. 6,566,450; U.S. Pat. No.7,488,790, and WO/2005/005493; (iii) combination of two metallocenes that are not supported on the polymerization of olefins, as mentioned in U.S. Pat. No. 0,234,547A1 and US2011257348A1; and (iv) polymerization of olefins by using a catalyst prepared by immobilizing two different metallocenes or one metallocene and one non-metallocene in the same support, as for instance in U.S. Pat. No. 719,302B2; U.S. Pat. No. 7,312,283B2; U.S. Pat. No.6,943,134B2; U.S. Pat. No.0,183,631A1; U.S. Pat. No. 5,525,678A; U.S.Pat. No. 7,199,072B2; U.S. Pat. No.199,072b2; U.S. Pat. No. 6,686,306B2, and U.S. Pat. No.6,001,766A. [0008] The use of catalytic systems for polymerizing olefins comprising supported metallocene catalysts comprising inorganic supports is extensively described in the literature (Hlatky, Chem. Rev. 100 (2000) 1347-1376; Severn et alli, Chem Rev. 105 (2005) 4073-4147). [0009] As can be seen from the prior art, silica has been the inorganic support at that is most widely employed in the development of supported metallocene catalysts. The surface and reactivity of the functional silica groups (isolated silanols, vicinal and geminal silanols, and siloxane) are well known. Obtaining them involves well-known pathways, among which is precipitation (precipitated silicas), and resulting from hydrolysis and reactions and condensation (xerogel silicas, aerogels, hydrogels). See, example, US 1970/3505785; US1971/3855172; DE1972/2224061; US1974/3668088; DE1975/2505191; US1975/3922393; DE1977/2719244; DE1976/2628975; US1979/4179431; EP1980/0018866; DE1986/3518738; DE1989/0341383; EP1989/0335195A2; US 1992/5118727 and US 1998/5723181. [0010] Various pathways for preparing supported metallocene catalysts have been described in the literature and may be classified into: [0011] (i) direct immobilization on silica as described in Santos et alli, Macromol. Chem. Phys. 198 (1997) 3529; Dos Santos et alli, J. Mol. Catal A; 139 (1999) 199; Dos Santos et alli, Macromol. Chem. Phys. 200 (1999) 751); [0012] (ii) immobilization on silica functionalized with methylaluminoxane (herein referred to as MAO), or with other types of catalysts, as described in US1989/4808561; US1989/4871705; US1990/4912075; US1990/4914253; US1990/4925821; US1990/4935397; US1990/4925217; US1990/4921825; US1991/5026797; US1991/5006500; US1992/5086025; US1993/5328892; WO1994/26793; US1995/5462999; WO1996/04318; US 1995/5468702; EU1997/849286; WO1997/42228; US1997/5629253; US1997/5661098; EU1998/922717; EU1998/856525; US1998/5712353; US1998/5739368; US1998/5763543; US1998/5719241; EU1999/989139; US1999/5968864; EU2000/1038855; US2000/6034024; WO2001/12684; WO2001/40323; US2001/6214953; EU2001/1167393; US2001/0051587; US2001/0053833; EU2002/1231225; US2002/40549; US2002/0107137; US2003/236365 and WO2004/055070; [0013] (iii) synthesis of metallocene situ on the support, as described in JP1990/0485306; US1996/5504408; US998/5739226; US2002/6399531; and US2002/326005; [0014] (iv) Immobilization on hybrid silica, as described in: Dos Santos et alli, Appl. Catal. A: Chemical 220 (2001) 287-392; Dos Santos et alli, Polymer 42 (2001) 4517-4525; Dos Santos et alli, J. Mol. Catal. A: Chemical 158 (2002) 541-557; and [0015] (v) Immobilization on silicas modified with spacers, as describes, for example, in US1995/5397757; US1995/257788 and US1997/5639835. [0016] The pathway (i) consists of the reaction between the silica silanol groups and the group that gives off the metallocene (chloride or hydride) in the presence of an organic solvent. The pathway (ii) essentially comprises pre-contact of the support with MAO or other alkylaluminums, followed by immobilization of the matallocene. In the pathway (iii), the silanol groups of the silica surface are reacted with compounds of the type MCl4 (M=Ti, Zr) and then with indenyl or cyclopentadienyl ions, or the sinanol groups of the silica surface are reacted organosilanes provided with ligands of the cyclopentadiene or indene type, which by deprotonation generate aromatic ions that may be metallized with reactants of the type MCl4 (M=Ti, Zr). Hybrid-silica immobilizing pathways (pathway iv) consist in obtaining a silica containing organic groups on the surface, obtained by the sol-gel method, followed by metallization. This pathway differs from the preceding one in that in pathway (iii) the silica employed is commercial, previously synthesized, whereas in the latter pathway the silica is synthesized already with the organic ligands (hybrid silicas). The pathway (iv) differs from the present invention in that the hybrid silica does not contain aliphatic organic groups and, therefore, does not generate a catalyst capable of producing polyethylenes that are bimodal or have broad distribution of molar mass. Finally, in the last pathway, the catalytic sites are generated or pushed off the surface (vertical spacers) or from each other (horizontal spacers). In both cases, the objective is to increase the catalytic activity of these supported metallocene catalysts. [0017] In the open literature, examples of these five pathways are commented in the bibliographic revisions of Hlatky ( Chem. Rev. 100 (2000) 1347-1376) and of Severn et al ( Chem Rev. 105 (2005) 4073-4147). Examples of these methodologies can also be found in documents WO 2006/131704; WO 2006/131703; JP 2006/233208; US 2006/135351; US 2006/089470; JP 2006/233208; US 2001/6239060 and EP 2000/1038885. [0018] Most patent documents that use chemically modified silica employs some type of commercial silica and modify it by grafting reactions or impregnation. [0019] O WO 2006/131704 describes the preparation of a supported catalyst, on which, after pre-contacting the co-catalyst with the catalyst (transition metal compounds, particularly metallocenes), in mole ration lower than 10:1, the mixture is contacted with a porous support, followed by removal of the solvent (impregnation method). The preparation method is simple, without implying loss of activity. The same thing happens in US 2006/089470, in which a homogeneous metallocene catalyst and a combination of alkylaluminoxane and alkiyaluminum are supported on silica, with average size of 540 μm. Metallocene catalyst and co-catalyst (aluminoxane or alkylaluminum) are also pre-contacted before being immobilized on spheroidal silica (5-40 μm) according to patent EP 200/1038885. In this case, 50% of the catalytic component is immobilized inside the support pores, which guarantees the production of a product having few gel imperfections. [0020] In WO 2006/131703, the porous support is pre-treated with a dehydrating agent and with a hydroxylated compound. The resulting support is then reacted with the catalyst (transition metal compound, such as metallocene, for example) and co-catalyst. The resulting supported catalyst is provided with enhanced catalytic activity. In document JP 2006/233208, the support is also pre-treated, but in this case with aluminoxane compounds, such as MAO, followed by reaction with metallocene. In this case, a part of the support is reacted with an ansa-metallocene and a part with an ansa-fluorenylmetallocen. In both cases, the metallocenes are individually treated with tri-isobutylaluminum (herein referred to as TIBA) and with 1-hexane. The final catalytic system is constituted by the combination of the two supported metallocenes and is active for co-polymerization of ethylene and 1-hexene. In US 2001/6239060, silica, after acidic treatment (HCl) and thermal treatment (110 and 800° C.), is functionalized previously with alkylaluminum and then contacted with metallocene-aluminoxane mixture. In WO 2002/038637, the process of preparing the supported metallocene catalyst is carried out by successive reaction of silica with ordinary alkylaluminum, and with borate derivatives, followed by addition of an ansa-metallocene. The final catalyst, active in the co-polymerization of ethylene and/or propylene with alpha-olefins, guarantees high contents of incorporated co-monomer. [0021] Organoaluminums of the type Et 2 AlH and Et 2 Al(OEt) were proposed as silica modifying agents in document WO 2003/053578. The resulting silica served as a support for immobilizing metallocene. The resulting system exhibited an increase in catalytic activity, attributed to the additional presence of co-catalysts on the silica surface. [0022] JP 2003/170058 describes the preparation of a support in which commercial silica pre-modified with ordinary alquylaluminum and with compounds having electroactive groups, such as 3,4,5-trifluorofenol. The modified silica is employed in the co-polymerization of olefins as a component of the catalytic system constituted by a metallocene and common alquylaluminum. This is no preparation of the final supported catalyst, but rather in situ immobilization, in which the ultimate heterogenization process takes place in situ, inside the polymerization reactor. [0023] JP 2006/274161 teaches the preparation of active supported catalysts for co-polymerization of olefins, capable of polymerizing ethylene and 1-butene in the presence of common alkylaluminums and producing co-polymers with short branching and molar mass distribution (herein referred to as DPM) of 6.8. Such catalysts use silica functionalized with organometallic compounds with metal of the groups 1 and 2, as for example Et2Zn, which is then treated in a number of steps with electron-donating organic solvents, water, before the immobilization of an ansa-metallocene. [0024] US 2006/135351 describes the preparation of the supported catalyst, wherein the metallocene has a functional group that facilitates and leads to a strong bond with the silica surface, used as support, minimizing bleaching processes. According to the technical description of this document, the polymerization takes place without “fouling” in the reactor, in both slurry process and in gaseous phase, and the morphology and density of the polymer produced are much better defined. [0025] Lewis bases such as pentafluorofenol were also used in the modification of silica. The immobilization of metallocenes and organometallic compounds such as chromocene, on the same support (silica) modified with Lewis bases and alkylaluminum generate active catalysts in the co-polymerization of ethylene and 1-hexene, with DPM of 10.9. [0026] WO 2004/018523 describes a process of preparing supported metallocene catalyst, in which the support (silica) is synthesized by a non-hydrolytic sol-gel process by condensing a silane containing anionic ligands, of a halogenated silane (r siloxane) and an alkoxysilane. The hybrid silica generated is then subjected to a metallization reaction, and the resulting catalyst is active, in the presence of a co-catalyst, in processes of polymerization olefins, in gaseous phase. [0027] As can be seen from the prior art, it is not described or expected that the immobilization of a single metallocene complex on a silica-base support results in a polyethylene with broad or bimodal mass distribution. Moreover, the use of hybrid silica provided with aliphatic organic groups, prepared by the sol-gel process, as a support for metallocene was not reported in the literature. [0028] Thus, the present invention relates to metallocene catalysts based on transition metal of the groups 4 and 5 of the periodic table, supported on a hybrid support for the production of homopolymers or copolymers of ethylene with alpha-olefins with broad or bipolar molar mass distribution. [0029] One also describes a process of preparing metallocene catalysts supported on a hybrid catalytic support and a process for the production of homopolymers or copolymers of ethylene with alpha-olefins with broad or bimodal molar mass distribution. [0030] The supported metallocene catalyst of the present invention exhibits, as its main advantage, the fact that it produces an ethylene polymer with broad or bimodal molar mass distribution using only one type of metallocene complex on the support. As a result, one obtains better processability of the resin obtained and, therefore, a potential reduction of the processing cost. OBJECTIVES OF THE INVENTION [0031] The present invention provides a metallocene catalyst based on transition metal of the groups 4 and 5 of the periodic table, supported on a hybrid catalytic support having aliphatic organic groups. [0032] One also describes a process for supporting metallocene on said hybrid support having aliphatic organic groups. [0033] The present invention also relates to a hybrid catalytic support containing aliphatic organic groups and to the process of preparing it, by means of a hydrolytic sol-gel pathway. [0034] Finally, the present invention relates to a process of producing homopolymers of ethylene and copolymers of ethylene with alpha-olefins with broad or bimodal molar mass distribution. [0035] The supported metallocene catalyst of the present invention exhibits, as its main advantage, the fact that one produces a polymer of ethylene with broad or bimodal molar mass distribution by using only one type of metallocene complex on the support. As a result, one obtains better processability of the resin obtained and, therefore, a potential reduction of processing cost. BRIEF DESCRIPTION OF THE INVENTION [0036] The present invention relates to a metallocene catalyst based on transition metal of the group 4 or 5 of the periodic table, supported on the hybrid catalytic support having aliphatic organic groups. [0037] A process of supporting metallocene on the hybrid catalytic support and a process of homopolymerizing ethylene or copolymerizing ethylene with alpha-olefins with broad or bimodal molar mass distribution are also described. [0038] The metallocene catalyst supported on a hybrid catalytic support of the invention comprises: [0039] (I) at least one metallocene derived from a compound of formula 1: [L] 2 -MQ 2 Formula (1), [0000] wherein: [0040] M is a transition metal of the group 4 or 5 of the periodic table; [0041] Q, which may be equal or different, comprise: halogen radical, aryl radical, alkyl radical containing 1 to 5 carbon atoms or alkoxy radical containing to 5 carbon atoms; and [0042] L is a ligand selected from: cyclopentadienyl, indenyl or fluorenyl, either substituted with hydrogen or not, alkyl, cycloalkyl, aryl, alkenyl, alkylaryl, arylalkyl or arylalkenyl, attached to the transition metal by bonding; [0043] (II) a hybrid catalytic support having at least one inorganic component and aliphatic organic groups. [0044] Preferably, the supported metallocene catalyst comprises at least one organometallic reactant containing a metal selected from the groups 2 or 13 of the periodic table. [0045] The process of obtaining supported metallocene catalysts based on transition metal of groups 4 or 5 of the periodic table of the present invention comprises: [0046] a) preparing the hybrid support having aliphatic organic groups; [0047] b) reacting the hybrid support obtained in step (a) with an organometallic reactant; [0048] c) reacting the product obtained in step (b) with the metallocene. [0049] In a preferred embodiment, the hybrid catalytic support is prepared according to the following steps: i) preparing an aqueous solution of a base diluted in alcohol; ii) adding a tetraalkylorthosilicate solution to the solution obtained in (i); iii) reacting a trialkoxydoorganosilicate solution with the solution obtained in (ii); iv) removing the solvent from the product of the reaction obtained in (iii). [0054] Preferably, the hybrid catalytic support is impregnated with a solution of organometallic compound from the groups 2 or 13 of the periodic table, in an inert organic solvent. [0055] In a preferred embodiment, the hybrid support obtained after impregnation reacts with a metallocene solution based on transition metal of the groups 4 or 5 of the periodic table in an inert organic solvent. After said reaction, the supported catalyst is washed and the solvent is removed. BRIEF DESCRIPTION OF THE FIGURES [0056] FIG. 1 —image of scanning electron microscopy of the hybrid support obtained in Example 1; [0057] FIG. 2 —image of scanning electron microscopy of the hybrid support obtained in Example 3; [0058] FIG. 3 —image of scanning electron microscopy of the hybrid support obtained in Example 4; [0059] FIG. 4 —image of scanning electron microscopy of the hybrid support obtained in Example 5; [0060] FIG. 5 —image of scanning electron microscopy of the hybrid support obtained in Example 6; [0061] FIG. 6 —GPC curve for the polyethylene prepared with the catalyst obtained in Example 8; [0062] FIG. 7 —GPC curve for the polyethylene prepared with the catalyst obtained in Example 9; [0063] FIG. 8 —GPC curve for the polyethylene prepared with the catalyst obtained in Example 7 (comparative). DETAILED DESCRIPTION OF THE INVENTION [0064] For a better understanding of the terms to be mentioned in the present specification, one should consider the following abbreviations and clarifications: hybrid support: a material constituted by an inorganic component and by at least one organic component; TEOS: tetraethoxylane; C contents: total percentage by mass of carbon in the hybrid catalytic support, determined by CHN on a CHN catalyst model 2400, manufactured by Perkin Elmer; Zr contents: total percentage by mass of zirconium in the supported metallocene catalyst, determined by Rutherford backscattering spectrometry on a 500 kV HVEE ion implanter; Al contents: total percentage by mass of aluminum in the supported metallocene catalyst, determined by SEM-EDX under a scanning electron microscope with energy-dispersive X-ray spectroscopy y spectrometer model JSM, manufactured by JEOL; TEAL: triethylaluminum; L 2 MX 2 : metallocene complex; Al/SiO2: ratio in weight percentage of transition metal belonging to the group 4 or 5 of the periodic table on silica, determined by Rutherford backscattering spectrometry on a 500 kV HVEE ion implanter. Al/M: mole ratio between aluminum of the co-catalyst and transition metal of the supported complex belonging to the group 4 or 5 of the periodic table; Catalytic activity: it represents the yield in kilograms (kg) of polymer produced per mole of transition metal belonging to the group 4 or 5 of the periodic table, present in the catalyst, and per hour of reaction; T m : it represents the measurement of the melting temperature in ° C. of the polymer, determined by Differential Scanning Calorimetry effected on a DSC 2920 analyzer manufactured by TA instruments; GPC: gel-permeation chromatography; M w : it represents average weight molecular mass of the polymers, determined by GPC effected on a GPCV 2000 equipment manufactured by Waters; M w /M n : it represents the molar mass distribution determined from the GPC curve effected on a GPCV 2000 Waters equipment. [0078] The hybrid catalytic support of the present invention is constituted by an inorganic component, preferably silica, and an organic component. Said organic component is constituted by aliphatic hydrocarbons (or aliphatic organic groups) with chain containing 1 to 40 carbon atoms bonded covalently to the inorganic component. Preferably, the aliphatic hydrocarbons used in the present invention contain from 8 to 22 carbon atoms. [0079] The hybrid catalytic support of the present invention exhibits aliphatic organic groups dispersed homogeneously at molecular level, both on the surface of the organic component and inside it. [0080] The hybrid catalytic support of the present invention is preferably obtained by means of a sol-gel pathway. The sol-gel pathway described in the present invention refers to a hydrolytic pathway in a base medium, wherein the base acts as a catalyst of the sol-gel reaction. This base accelerates the hydrolysis reaction and condensation reaction of the reactants present in said reaction. [0081] The hybrid catalytic support of the present invention preferably has spherical and lamellar morphology and is provided with aliphatic organic groups. [0082] In a preferred embodiment, the process of preparing the hybrid catalytic support comprises the following steps: i) diluting an aqueous solution of a base in an alcohol; ii) adding an alcoholic solution of tetraalkylorthosilicate onto the solution obtained in steps (i); iii) reacting a solution of trialkoxydoorganosilane with the solution obtained in step (ii); and iv) removing the solvent that is present in the reaction product obtained in step (iii). [0087] According to step (i) of the process of preparing the catalytic support of the present invention, the aqueous solution of a base with concentrations ranging from 0.1 to 5 mole/L is diluted in an alcohol. [0088] The dilution factor (aqueous solution of a base/alcohol) ranges from 10 to 300. Preferably, one uses the dilution factor of 100. [0089] The bases that may be used in step (i) of preparing the hybrid catalytic support are selected from hydroxides of the group I and II, aliphatic and aromatic amines, ammonium hydroxide and/or mixture thereof. Preferably, ammonium hydroxide is used. The pH of the base solution ranges from 8 to 14. [0090] The alcohols that may be used in step (i) of preparing the hybrid catalytic support are selected from: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-ehxanol and/or mixtures thereof. Preferably, ethanol is used. [0091] The aqueous base solution and the alcohol are subjected to stirring, the stirring velocity ranging from 50 rpm to 40,000 rpm. [0092] In step (ii) of the process of preparing the hybrid catalytic support, an alcoholic solution of tetraalkylorthosilicate is added on the solution obtained in (i). [0093] The alcohols used in step (ii) comprise: methanol, ethanol, 1-propanol, 2-propanol, 1-buthanol, 2-buthanol, 1-penthanol, 2-pentanol, 1-hexanol, 2-hexanol and/or mixtures thereof. [0094] Non limiting examples of the tetraalkylorthosilicates that are used in the present invention include: tetramethylorthosilicate (TMOS), tetraethylorthosilicate (TEOS), tetrapropylorthosilicate (TPOS), tetrabutylorthosilicate (TBOS) and/or mixtures thereof. Preferably, TEOS is used. [0095] The stirring velocity of the mixture obtained in step (ii) is kept between 50 and 40,000 rpm. [0096] The reaction time of this mixture ranges from 0.1 to 24 hours. Preferably, 2 hours are used. This mixing and stirring step may also be carried out simultaneously in step (iii). [0097] Step (iii) of the process of preparing the hybrid catalytic support comprises reacting a trialkoxyorganosiliane with the solution obtained in step (ii). [0098] The trialkoxyorganosilane has carbon chain ranging from 1 to 40 carbon atoms. Preferably, a trialkoxyorganosilane with 8 to 22 carbon atoms is used. [0099] The alkoxide grouping of said reactant should have from 1 to 4 carbon atoms. Preferably, the alkoxide grouping with 1 carbon atom is used. [0100] Non-limiting examples of trialkoxyorganosilanes that are used in the present invention include: hexadecyltrimethoxysiliane (HDS), heptadecyltrimethoxysiliane (HPDS), octadecyltrimethoxysiliane (ODS), hexadecyltriethoxysiliane (HDES), heptadecyltriethoxysilane (HPDES), octadecyltriethoxysilane (ODES) and/or mixture thereof. Preferably, ODS is used. [0101] The mole ratio of trialkoxyorganosilane:tetraalkylorthosilicate ranges from 1:0 to 1:100, preferably from 1:1 to 1:60. [0102] The addition of trialkoxyorganosilane to the solution obtained in (ii) may be made concomitantly or until 24 hours after addition of tetraalkylorthosilicate. Preferably, the addition of trialkoxyorganosilane is carried out 2 hours after addition of tetraalkylorthosilicate. The reaction is kept for an additional time ranging from 0.1 to 48 h, preferably 2 hours. [0103] The stirring velocity during the reaction should be kept between 50 and 40,000 rpm. Preferably, one uses a stirring velocity of 150 rpm. This step may be carried out simultaneously with step (ii). [0104] In step (iv) of the process of preparing the hybrid catalytic support, one carries out the removal of the solvent that is present in the reaction product obtained in (iii). [0105] The removal of the solvent may be carried out by evaporation at room temperature, filtration, centrifugation, or under reduced pressure. Preferably, one uses reduced pressure in a time ranging from 1 to 24 hours. [0106] The contents of aliphatic organic groups, measured through the C content, of the hybrid catalytic support, obtained in the above-described process, range from 0.5 to 80%. The number of aliphatic organic groups in the catalytic hybrid supports influences the Mw/Mn of the ethylene polymers. [0107] The metallocene catalyst supported in a hybrid catalytic support having aliphatic organic groups of the invention comprises: [0000] at least one metallocene derived from a compound of formula 1: [L 2 -MQ 2 formula (1), wherein: [0108] M is a transition metal of the group 4 or 5 of the periodic table; [0109] Q, which may be equal or different, comprise: halogen radical, aryl radical, alkyl radical containing 1 to 5 carbon atoms or alkoxy radical containing to 5 carbon atoms; and [0110] L is a ligand selected from: cyclopentadienyl, indenyl or fluorenyl, either substituted with hydrogen or not, alkyl, cycloalkyl, aryl, alkenyl, alkylaryl, arylalkyl or arylalkenyl, attached to the transition metal by bonding; [0000] a hybrid catalytic support having at least one inorganic component and aliphatic organic groups. [0111] Preferably, the supported metallocene catalyst comprises at least one organometallic reactant containing a metal selected from the groups 2 or 13 of the periodic table. More preferably, in the process of preparing the metallocene catalysts, one carries out impregnation of the hybrid support obtained in the preceding step (iv), with a solution of organometallic compound of group 2 or 13 of the periodic table, in an inert organic solvent. [0112] The organometallic compounds that may be used in the step of impregnating the hybrid support are selected from: trimethylaluminum (TMAL)\, triethylaluminum (TEAL), tri-isobutylaluminum (TIBAL), tri-n-hexylaluminum (TNHAL), tri-n-octylaluminum (TNOAL), dimethylaluminum chloride (DMAC), methylaluminum dichloride (MADC), dimethylaluminum dichloride, ethylaluminum dichloride (EADC), di-isobutylaluminum chloride (DIBAC), isobuthylaluminum dichloride (MONIBAC), butyl ethylmagnesium (BEM), butyl octylmagnesium (BOMAG), methyl magnesium chloride, ethylmagnesium chloride and/or mixtures thereof. These compounds may be used in the concentrated or dissolved form. In a preferred embodiment, one uses dissolved compounds in an organic solvent of the aliphatic hydrocarbon type. [0113] When using more than one organometallic compound of the group 2 or 13 of the periodic table in the step of impregnating the hybrid support, the different compounds may be fed to the same solution or to individual solutions, either at the same time or in subsequent additions. [0114] Non-limiting examples of inert organic solvents that may be used for solubilizing the organometallic compound of the group 2 or 13 of the periodic table are selected from: toluene, cyclohexane, n-hexane, n-heptane and n-octane and/or mixtures thereof. [0115] In the step of impregnating the hybrid catalytic support one employs an amount of solvent sufficient to suspend the material. [0116] The amount of organometallic compound of the group 2 or 13 of the periodic table that may be used ranges from 1 to 60% by mass of metal with respect to the mass of hybrid catalytic support. Preferably, one should use an amount ranging from 5 and 30% of metal. [0117] The reaction time of the step of impregnating the hybrid support should range from 0.1 h to 24 h, preferably from 0.5 h to 3 h, and the reaction temperature ranges from −10C to 80° C., preferably from 0 to 30° C. [0118] After impregnation, the hybrid catalytic support obtained reacts with a metallocene solution based on transition metal of groups 4 or 5 of the periodic table in an inert organic solvent. [0119] The metallocene is derived from a compound of formula 1: [0000] formula (1), [0000] [L 2 -MQ 2   (I) [0000] wherein: [0120] M is a transition metal of the group 4 or 5 of the periodic table; [0121] Q, which may be equal or different, comprise: halogen radical, aryl radical, alkyl radical containing 1 to 5 carbon atoms or alkoxy radical containing to 5 carbon atoms; and [0122] L is a ligand selected from: cyclopentadienyl, indenyl or fluorenyl, either substituted with hydrogen or not, alkyl, cycloalkyl, aryl, alkenyl, alkylaryl, arylalkyl or arylalkenyl, attached to the transition metal by bonding. [0123] Representative but non-limiting examples of compounds having the formula 1 include: Cp 2 TiCl 2 , Cp 2 ZrCl 2 , Cp 2 HfCl 2 , Cp 2 VCl 2 , Cp 2 Ti(Me) 2 , Cp 2 Zr(Me) 2 , Cp 2 Hf(Me) 2 , Cp 2 Ti(OMe) 2 , Cp 2 Zr(OMe) 2 , Cp 2 Hf (OMe) 2 , Cp 2 Ti(OEt) 2 , Cp 2 Zr(OEt) 2 , Cp 2 Hf(OEt) 2 , Ind 2 TiCl 2 , Ind 2 ZrCl 2 , Ind 2 HfCl 2 , Ind 2 VCl 2 , Ind 2 Ti(Me) 2 , Ind 2 Zr(Me) 2 , Ind 2 Hf(Me) 2 , Ind 2 Ti(Me) 2 , Ind 2 Zr(OMe) 2 , Ind 2 Hf(OMe) 2 , Ind 2 Ti(OEt) 2 , Ind 2 Zr(OEt) 2 , Ind 2 Hf(OEt) 2 , Flu 2 TiCl 2 , FIu 2 ZrCl 2 , Flu 2 HfCl 2 , FIu 2 VCl 2 , Flu 2 Ti(Me) 2 , Flu 2 Zr(Me) 2 , Flu 2 Hf(Me) 2 , Flu 2 Ti(OMe) 2 , Flu 2 Zr(OMe) 2 , Flu 2 Hf(OMe) 2 , Flu 2 Ti(OEt) 2 , Flu 2 Zr(OEt) 2 , Flu 2 Hf(OEt) 2 , (MeCp) 2 TiCl 2 , (MeCp) 2 ZrCl 2 , (MeCp) 2 HfCl 2 , (MeCp) 2 VCl 2 , (MeCp) 2 Ti(Me) 2 , (MeCp) 2 Zr(Me) 2 , (MeCp) 2 Hf(Me) 2 , (MeCp) 2 Ti(OMe) 2 , (MeCp) 2 Zr(OMe) 2 , (MeCp) 2 Hf (OMe) 2 , (MeCp) 2 Ti(OEt) 2 , (MeCp) 2 Zr(OEt) 2 , (MeCp) 2 Hf(OEt) 2 , (nBuCp) 2 TiCl 2 , (nBuCp) 2 ZrCl 2 , (nBuCp) 2 HfCl 2 , (nBuCp) 2 VCl 2 , (nBuCp) 2 Ti (Me) 2 , (nBuCp) 2 Zr(Me) 2 , (nBuCp) 2 Hf(Me) 2 , (nBuCp) 2 Ti(OCH 3 ) 2 , (nBuCp) 2 Zr (OCH 3 ) 2 , (nBuCp) 2 Hf(OCH 3 ) 2 , (nBuCp) 2 Ti(OEt) 2 , (nBuCp) 2 Zr (OEt) 2 , (nBuCp) 2 Hf(OEt) 2 , (Me 5 Cp) 2 TiCl 2 , (Me 5 Cp) 2 ZrCl 2 , (Me 5 Cp) 2 HfCl 2 , (Me5Cp) 2 VCl 2 , (Me 5 Cp) 2 Ti(Me) 2 , (Me 5 Cp) 2 Zr(Me) 2 , (Me 5 Cp) 2 Hf(Me) 2 , (Me 5 Cp) 2 Ti(OMe) 2 , (Me 5 Cp) 2 Zr(OMe) 2 , (Me 5 Cp) 2 Hf(OMe) 2 , (Me 5 Cp) 2 Ti(OEt) 2 , (Me 5 Cp) 2 Zr(OEt) 2 , (Me 5 Cp) 2 Hf(OEt) 2 , (4,7-Me 2 Ind) 2 TiCl 2 , (4,7-Me 2 Ind) 2 ZrCl 2 , (4,7-Me 2 Ind) 2 HfCl 2 , (4,7-Me 2 lnd) 2 VCl 2 , (4,7-Me 2 lnd) 2 Ti(Me) 2 , (4,7-Me 2 lnd) 2 Zr (Me) 2 , (4,7-Me 2 lnd) 2 Hf(Me) 2 , (4,7-Me 2 lnd) 2 Ti(OMe) 2 , (4,7-Me 2 lnd) 2 Zr(OMe) 2 , (4,7-Me 2 lnd) 2 Hf(OMe) 2 , (4,7-Me 2 lnd) 2 Ti(OEt) 2 , (4,7-Me 2 lnd) 2 Zr(OEt) 2 , (4,7-Me 2 Ind) 2 Hf(OCH 2 CH 3 ) 2 , (2-Melnd) 2 TiCl 2 , (2-Melnd) 2 ZrCl 2 , (2-Melnd) 2 HfCl 2 , (2-Melnd) 2 VCl 2 , (2-Melnd) 2 Ti(Me) 2 , (2-Melnd) 2 Zr(Me) 2 , (2-Melnd) 2 Hf(Me) 2 , (2-Melnd) 2 Ti(OMe) 2 , (2-Melnd) 2 Zr(OMe) 2 , (2-Melnd) 2 Hf(OMe) 2 , (2-Melnd) 2 Ti (OEt) 2 , (2-Melnd) 2 Zr(OEt) 2 , (2-Melnd) 2 Hf(OEt) 2 , (2-arillnd) 2 TiCl 2 , (2-arillnd) 2 ZrCl 2 , (2-arillnd) 2 HfCl 2 , (2-arillnd) 2 VCl 2 , (2-arillnd) 2 Ti(Me) 2 , (2-arillnd) 2 Zr (Me) 2 , (2-arillnd) 2 Hf(Me) 2 , (2-arillnd) 2 Ti(OMe) 2 , (2-arillnd) 2 Zr(OMe) 2 , (2-arillnd) 2 Hf(OMe) 2 , (2-arillnd) 2 Ti(OEt) 2 , (2-arillnd) 2 Zr(OEt) 2 , (2-arillnd) 2 Hf (OEt) 2 , (4,5,6,7-H 4 Ind) 2 TiCl 2 , (4,5,6,7-H 4 Ind) 2 ZrCl 2 , (4,5,6,7-H 4 Ind) 2 HfCl 2 , (4,5,6,7-H 4 lnd) 2 VCl 2 , (4,5,6,7-H 4 lnd) 2 Ti(Me) 2 , (4,5,6,7-H 4 lnd) 2 Zr(Me) 2 , (4,5,6,7-H 4 Ind) 2 Hf(Me) 2 , (4,5,6,7-H 4 Ind) 2 Ti(OMe) 2 , (4,5,6,7-H 4 Ind) 2 Zr(OMe) 2 , (4,5,6,7-H 4 Ind) 2 Hf(OMe) 2 , (4,5,6,7-H 4 Ind) 2 Ti(OEt) 2 , (4,5,6,7-H 4 Ind) 2 Zr(OEt) 2 , (4,5,6,7-H 4 Ind) 2 Hf(OEt) 2 , (9-MeFlu) 2 TiCl 2 , (9-MeFlu) 2 ZrCl 2 , (9-MeFlu) 2 HfCl 2 , (9-MeFlu) 2 VCl 2 , (9-MeFlu) 2 Ti(Me) 2 , (9-MeFlu) 2 Zr(Me) 2 , (9-MeFlu) 2 Hf(Me) 2 , (9-MeFlu) 2 Ti(OMe) 2 , (9-MeFlu) 2 Zr(OMe) 2 , (9-MeFlu) 2 Hf(OMe) 2 , (9-MeFlu) 2 Ti (OEt) 2 , (9-MeFlu) 2 Zr(OEt) 2 , (9-MeFlu) 2 Hf(OEt) 2 . [0124] Non-limiting examples of inert organic solvents that may be used for solubilizing said metallocene are: toluene, cyclohexane, n-hexane, n-heptane, n-octane and/or mixtures thereof. [0125] One uses an amount sufficient to suspend the material. [0126] The amount of said metallocene that may be used in the present invention ranges from 0.1 to 10% by mass of the metal with respect to the mass of the catalytic hybrid support, preferably from 0.1 to 2%. The reaction temperature should range from 0 to 60° C., preferably from 10 to 30C. The reaction time should range from 0.1 h to 24 h, preferably from 0.5 to 4 hours. [0127] After reacting the metallocene with the impregnated hybrid catalytic support, the solid product obtained (supported metallocene catalyst) is washed, and the solvent contained in the product is removed. [0128] The washing of the supported metallocene catalyst obtained is carried out with a sufficient amount of organic solvent. The wash temperature may range from room temperature to 70° C. Non-limiting examples of organic solvents include: toluene, cyclohexane, n-hexane, n-heptane and n-octane. [0129] The removal of the supported metallocene catalyst is made with reduced pressure in a time ranging from 1 to 24 h with a vacuum pump. [0130] The contents of metal of the group 2 or 13 of the periodic table in the supported metallocene catalysts range from 1 to 60%. [0131] The contents of metal of the group 4 or 5 of the periodic table in the supported metallocene catalysts range from 0.1 to 10%. [0132] The supported metallocene catalysts of the present invention are suitable for being used in processes of homopolymerizing ethylene and co-polymerizing ethylene with α-olefins in suspension or gas phase processes. The α-olefins are selected from: propene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-docedene. [0133] The supported metallocene catalysts of the present invention exhibit catalytic activity ranging from 20 to 10000 kg inch/mole M.h. [0134] During the ethylene homopolymerization process and ethylene co-polymerization process with a-olefins, one uses, in addition to the supported complex of the present invention, an alkylaluminum co-catalyst, the preferred forms being MAO, TMAL, TEAL or TIBAL. [0135] The molar ratio of co-catalyst/catalyst (Al/M) ion the ethylene homopolymerization and co-polymerization ranges from 500 to 2000, preferably from 1000 to 1500. [0136] The homopolymers and copolymers obtained with the supported metallocene catalysts of the present invention exhibit a broad distribution of molar mass, comprising Mw/Mn in the range from 2 to 200 and Mw in the range from 100 to 200 kg/mole. [0137] For a better understanding of the invention and of the improvements achieved, one presents hereinafter a few comparative examples and embodiment examples, which should not be considered limitative of the scope and reach of the invention. [0138] In the examples of the present invention, which should not be considered limitative, TEOS (Merck, >98% purity) and octadecyltrimethoxysilane (Aldrich, 90% purity), ethanol (Merck, 99.8% purity) and ammonia solution (Dinâmica, 25% ammonia), TEAL (Akzo, 10% Al), MAO (Akzo, 10% Al) and the biscyclopentadienyl zirconium IV chloride (Boulder) are used without previous purification. [0139] Toluene (Nuclear, 98% purity) and 1-hexene (Merck), used in preparing the supported metallocene catalyst and in co-polymerizing ethylene with alpha-olefins, is dried according to the conventional techniques. All the manipulations were carried out by using inert nitrogen atmosphere with maximum limit of 1.5 ppm of humidity. [0140] Example 1 describes the preparation of a non-hybrid silica support (comparative). Examples 2 to 6 describe the preparation of the hybrid catalytic supports with different contents of aliphatic organic groups with 18 carbon atoms. Examples 7 to 12 illustrate the synthesis of supported metallocene catalysts prepared with the supports of examples 2 to 6. EXAMPLE 1 Preparation of a (Comparative) Conventional Catalytic Support [0141] This example illustrates the use of TEOS as an agent for preparing a non-hybrid catalytic support based on silica. [0142] In a solution containing 200 mL ethanol and 40 mL ammonia solution, under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mL TEOS in ethanol. The suspension is left under stirring at the temperature of 25° C. for 2 h, and the resulting solid is dried, washed with ethanol and dried again in vacuum. [0143] This component obtained was characterized, exhibiting the following characteristics: [0144] C content: [0145] 2.5% (w/w)— FIG. 1 . [0146] The use of TEOS without octadecyltrimethoxysilane in preparing the support results in a silica with 2.5% carbon. In this case, since the support does not have aliphatic organic groups, the organic content is attributed to the presence of residual ethoxyde groups. According to FIG. 1 , this support exhibits a spherical morphology. EXAMPLE 2 Preparation of Hybrid Catalytic Support [0147] This example illustrates the use of TEOS and octadecyltrimethoxysilane at the molar ratio of 50:1, as reactants for preparing the hybrid catalytic support having aliphatic organic groups. [0148] In a solution containing 200 mL ethanol and 400 mL ammonia solution, under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mL TEOS in ethanol. The suspension is kept under stirring at the temperature of 25° C. for 2 h. After this period, one adds, drop by drop, 5 mL of a solution containing 0.085 mL of octadecyltrimethoxysilane in ethanol. The suspension is kept under stirring at the temperature of 25° C. for a further 2 hours, and the resulting solid is dried in vacuum, washed with ethanol and dried again in vacuum. [0149] This component obtained was characterized, exhibiting the following characteristics: [0150] C content: 5.1% w/w). [0151] The carbon content obtained for this support (5.1%) is higher than that observed in the support of the comparative example (Example 1), which demonstrates the incorporation of the hydrocarbon groups of the octadecyl type (with 18 carbon atoms) in the support and, therefore, proves the formation of the hybrid support. EXAMPLE 3 Preparation of the Hybrid Catalytic Support [0152] This example illustrates the use of TEOS and octadecyltrimethoxysilane at the molar ratio of: 20:1, as reactants for preparing the hybrid catalytic support provided with aliphatic organic groups. [0153] In a solution containing 200 mL ethanol and 400 mL of ammonia solution, under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mL of TEOS in ethanol. The suspension is kept under stirring at the temperature of 25° C. for 2 h. After this period, one adds, drop by drop, 5 mL of a solution containing 0.21 mL of octadecyltrimethosysilane in ethanol. The suspension is kept under stirring at the temperature of 25° C. for a further 2 h, and the resulting solid is dried in vacuum, washed with ethanol and dried again in vacuum. [0154] This component obtained was characterized, exhibiting the following characteristics: [0155] C content: 10.8% (w/w)— FIG. 2 . [0156] The carbon content obtained for this support (10.8%) is higher than that observed in the support of Example 2, which demonstrates a larger number of hydrocarbon groups of the octadecyl type (with 18 carbon atoms) in this support. According to FIG. 2 , this support exhibits a spherical morphology with lamellar covering. EXAMPLE 4 Preparation of the Hybrid Catalytic Support [0157] In a solution containing 200 mL ethanol and 400 mL of ammonia solution, under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mL of TEOS in ethanol. The suspension is kept under stirring at the temperature of 25° C. for 2 h. After this period, one adds, drop by drop, 5 mL of a solution containing 0.42 mL of octadecyltrimethosysilane in ethanol. The suspension is kept under stirring at the temperature of 25° C. for a further 2 h, and the resulting solid is dried in vacuum, washed with ethanol and dried again in vacuum. [0158] This component obtained was characterized, exhibiting the following characteristics: [0159] C content: 19.8% (w/w)— FIG. 3 . [0160] The carbon content obtained for this support (19.8%) is higher than that observed in the support of Example 3, which demonstrates a larger number of hydrocarbon groups of the octadecyl type (with 18 carbon atoms) in the support. According to FIG. 3 , this support exhibits a spherical morphology with lamellar domains. EXAMPLE 5 Preparation of the Hybrid Catalytic Support [0161] This example illustrates the use of TEOS and octadecyltrimethoxysilane at the molar ratio of 5:1, as agents for preparing the hybrid catalytic support provided with aliphatic organic groups. [0162] In a solution containing 200 mL ethanol and 400 mL of ammonia solution, under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mL of TEOS in ethanol. The suspension is kept under stirring at the temperature of 25° C. for 2 h. After this period, one adds, drop by drop, 5 mL of a solution containing 0.84 mL of octadecyltrimethosysilane in ethanol. The suspension is kept under stirring at the temperature of 25° C. for a further 2 h, and the resulting solid is dried in vacuum, washed with ethanol and dried again in vacuum. [0163] This component obtained was characterized, exhibiting the following characteristics: [0164] C content: 37.3% (w/w)— FIG. 4 . [0165] The carbon content obtained for this support (37.3%) is higher than that observed in the support of Example 4, which demonstrates a larger number of hydrocarbon groups of the octadecyl type (with 18 carbon atoms) in this support. According to FIG. 4 , this support exhibits a spherical and lamellar morphology. EXAMPLE 6 Preparation of the Hybrid Catalytic Support [0166] This example illustrates the use of octadecyltrimethoxysilane without TEOS as a reactant for preparing the hybrid catalytic support provided with aliphatic organic groups. [0167] In a solution containing 200 mL ethanol and 40 mL of ammonia solution, under stirring of 150 rpm, one adds 10 mL of a solution containing 2 mL of octadecyltrimethoxysilane in ethanol. The suspension is kept under stirring at the temperature of 25° C. for 2 hours, and the resulting solid is dried, washed with ethanol and dried again in vacuum. [0168] This component obtained was characterized, exhibiting the following characteristics: [0169] C content: 68.6% (w/w)— FIG. 5 . [0170] The carbon content obtained for this support (68.6%) is higher than that observed in the support of Example 5, which demonstrates a larger number of hydrocarbon groups of the octadecyl type (with 18 carbon atoms) in support. According to FIG. 5 , this support exhibits a lamellar morphology. [0171] Considering the results of Examples 2 to 6, the increase in the number of hydrocarbon groups of the octadecyl type in the support entails an increase in the domains with lamellar morphology and, consequently, reduction of the sphericity of the support particles. EXAMPLES 7-12 Preparation of the Supported Metallocene Catalyst [0172] In 50 mL of toluene, under stirring of 150 rpm, one suspends 1 g of the hybrid catalytic support obtained according to the examples described above. To the suspension one adds 2 mL of TEAL solution at a temperature of 25° C. This suspension is kept at this temperature and under stirring for 1 hour. After this period, in the same experimental conditions, one adds to the suspension 10 mL of a solution containing 32 mg of biscyclopentadienyl zirconium IV chloride in toluene. The reaction is carried out in a 2-hour period. After this period, the resulting solid is dried, washed with toluene and dried again in vacuum. [0173] The results of contents of Al and Zr for the supported metallocene catalysts obtained with the hybrid catalytic support of Examples 1-6 are presented in Table 1. [0000] TABLE 1 Results of the contents of Al and Zr for the supported metallocene catalysts obtained from the hybrid catalytic supports as described in Examples 1 to 6. Supported Content Content Metallocene of Al of Zr Hybrid catalytic support catalyst (% w/w) (% w/w) Example 1 Example 7 1.0 0.5 Example 2 Example 8 8.6 0.5 Example 3 Example 9 7.2 0.5 Example 4 Example 10 n.d. 0.2 Example 5 Example 11 1.1 0.1 Example 6 Example 12 n.d. 0.3 n.d.: Not determined. [0174] According to Table 1, the Al content in the supported metallocene catalysts prepared with the supports of Examples 1 to 6 ranges from 1 to 9%. These results demonstrate the presence of TEAL in the composition of the supported metallocene catalysts. The Zr contents in the supported metallocene catalysts range from 0.1 to 0.5%. One observes that, for the catalysts synthesized with the supports prepared by using TEOS (Examples 7-11), the systems with higher contents of octadecyl groups exhibit content of Zr and, therefore, of immobilized metallocene complex (Examples 10 and 11). For systems with lower contents of octadecyl groups (Examples 8 and 9), there is no reduction of the contents of the immobilized metallocene complex as compared with the metallocene catalytic system prepared by using the non-hybrid support (Example 7). EXAMPLE 13 Polymerizations [0175] In a glass reactor with 300 mL capacity and under magnetic stirring, one adds toluene in nitrogen atmosphere. The temperature is adjusted to 60° C. with the aid of a thermostatized bath. An amount of 10 mL of TEAL is added for washing the reactor. The washing time is of at least thirty minutes. The wash liquid is removed from the reactor by siphoning. After washing the reactor, one adds toluene and MAO and then the reactor is purged with ethylene. Once the purging has been carried out, the metallocene catalyst supported in a hybrid support, dissolved in toluene, is added to the reactor, forming a catalytic system with concentration of Zr of 10 −6 Mole/L and with Al/Zr ratio preferably of 1500. The ethylene pressure is adjusted to 1.6 atm, and polymerization is carried out for 30 min. the resulting polymer is precipitated in acidified ethanol solution, filtered, washed with water and ethanol and dried in an oven in vacuum. For copolymerization, 15 mL of 1-hezen are added just before adding the supported metallocene catalyst. [0176] The results of catalytic activity in the polymerization of the ethylene of the supported metallocene catalysts obtained with the hybrid catalytic supports of spherical and/or lamellar morphology are presented in Table 2. [0000] TABLE 2 Catalytic activity obtained in the polymerization of the ethylene by using supported metallocene catalysts. Catalytic activity Supported metallocene catalyst (kg pol/mole Zr · h) Example 7 30 Example 8 690 Example 8* 870 Example 9 860 Example 10 310 Example 11 450 Example 12 200 *In this case, a co-polymerization of ethylene with 1-hexene was carried out. [0177] According to Table 2, the supported metallocene catalysts prepared with the hybrid supports provided with octadecyl groups (Example 8-12) exhibit catalytic activities superior to that observed for the supported metallocene catalyst prepared by using a non-hybrid support of Example 7 (comparative). [0178] The results of the properties of the polymers formed are presented in Table 3 below. [0000] TABLE 3 Properties of the polymers obtained with supported metallocene catalyst. Supported metallocene catalyst Tm (° C.) Mw (kg/mole) Mw/Mn Example 7 132 240 2.2 Example 8 133 450 3.6 Example 8* 112 170 5.4 Example 9 133 250 6.1 Example 10 133 360 2.6 Example 11 133 580 3.5 Example 12 133 680 2.9 *In this case, a co-polymerization of ethylene with 1-hexen was carried out. [0179] According to Table 3, the ethylene polymers produced by using the supported metallocene catalysts prepared with the hybrid supports having ocadecyl groups (Examples 8-12) exhibit molar masses (Mw) higher than that observed for the ethylene polymer produced with the metallocene catalyst of Example 7 (comparative). With regard to the distribution of molar mass (Mw/Mn) of the polyethylenes, the polymers produced by using the supported metallocene catalysts prepared with the hybrid catalytic supports having octadecyl groups (Examples 8-12) have broadened values with respect to that observed for the polymer produced with the metallocene catalyst of Example 7 (comparative), which suggests better processability of the polymers prepared with the catalysts of the present invention. In addition to the broadening of the polydispersion, the polymers obtained with the supported metallocene catalysts of the present invention exhibit a bimodal molar mass distribution, as can be observed in FIGS. 6 and 7 , unlike the polymer prepared with the catalyst of the comparative example (Example 7), wherein the molar mass distribution is unimodal ( FIG. 8 ). [0180] These results demonstrate that the broadening of the molar mass distribution of the polyethylenes is achieved by using a single type of immobilized metallocene complex in the supports and is the effect of the modification of inorganic component by the aliphatic organic groups. [0181] Therefore, the considerations and examples of the present specification demonstrate the distinctive points of the present invention with respect to the prior art, which make the inventive process non-suggested and non-evident in the face of the literature published on the subject. [0182] A preferred example of embodiment having been described, it should be understood that the scope of the present invention embraces other possible variations, being limited only by the contents of the accompanying claims which include the possible equivalents.

The present invention relates to a metallocene catalyst based on a transition metal of group 4 or 5 of the periodic table, supported on a hybrid catalytic support provided with aliphatic organic groups. One also describes a process for supporting metallocene on said hybrid catalytic support of aliphatic organic groups. The supported metallocene catalyst of the present invention exhibits, as its main advantage, the fact of producing an ethylene polymer with broad or bimodal molar mass distribution, by using only one type of metallocene complex on the support. As a result, on obtains, better processability of the resin obtained and, therefore, a potential reduction of the processing cost.

This application claims benefit of 60/625,377, filed Nov. 5, 2004. FIELD OF THE INVENTION The present invention relates to a method and an apparatus for the use of carbon-isotope monoxide in labeling synthesis. More specifically, the invention relates to a method and apparatus for producing an [ 11 C]carbon monoxide enriched gas mixture from an initial [ 11 C]carbon dioxide gas mixture, and using the produced gas mixture in labeling synthesis by photo-initiated carbonylation. Radiolabeled amides are provided using amines treated with alkali metal base and alkyl iodides as precursors. BACKGROUND OF THE INVENTION Tracers labeled with short-lived positron emitting radionuclides (e.g. 11 C, t 1/2 =20.3 min) are frequently used in various non-invasive in vivo studies in combination with positron emission tomography (PET). Because of the radioactivity, the short half-lives and the submicromolar amounts of the labeled substances, extraordinary synthetic procedures are required for the production of these tracers. An important part of the elaboration of these procedures is development and handling of new 11 C-labelled precursors. This is important not only for labeling new types of compounds, but also for increasing the possibility of labeling a given compound in different positions. During the last two decades carbonylation chemistry using carbon monoxide has developed significantly. The recent development of methods such as palladium-catalysed carbonylative coupling reactions has provided a mild and efficient tool for the transformation of carbon monoxide into different carbonyl compounds. Carbonylation reactions using [ 11 C]carbon monoxide has a primary value for PET-tracer synthesis since biologically active substances often contain carbonyl groups or functionalities that can be derived from a carbonyl group. The syntheses are tolerant to most functional groups, which means that complex building blocks can be assembled in the carbonylation step to yield the target compound. This is particularly valuable in PET-tracer synthesis where the unlabelled substrates should be combined with the labeled precursor as late as possible in the reaction sequence, in order to decrease synthesis-time and thus optimize the uncorrected radiochemical yield. When compounds are labeled with 11 C, it is usually important to maximize specific radioactivity. In order to achieve this, the isotopic dilution and the synthesis time must be minimized. Isotopic dilution from atmospheric carbon dioxide may be substantial when [ 11 C]carbon dioxide is used in a labeling reaction. Due to the low reactivity and atmospheric concentration of carbon monoxide (0.1 ppm vs. 3.4×10 4 ppm for CO 2 ), this problem is reduced with reactions using [ 11 C]carbon monoxide. The synthesis of [ 11 C]carbon monoxide from [ 11 C]carbon dioxide using a heated column containing reducing agents such as zinc, charcoal or molybdenum has been described previously in several publications. Although [ 11 C]carbon monoxide was one of the first 11 C-labelled compounds to be applied in tracer experiments in human, it has until recently not found any practical use in the production of PET-tracers. One reason for this is the low solubility and relative slow reaction rate of [ 11 C]carbon monoxide which causes low trapping efficiency in reaction media. The general procedure using precursors such as [ 11 C]methyl iodide, [ 11 C]hydrogen cyanide or [ 11 C]carbon dioxide is to transfer the radioactivity in a gas-phase, and trap the radioactivity by leading the gas stream through a reaction medium. Until recently this has been the only accessible procedure to handle [ 11 C]carbon monoxide in labeling synthesis. With this approach, the main part of the labeling syntheses with [ 11 C]carbon monoxide can be expected to give a very low yield or fail completely. There are only a few examples of practically valuable 11 C-labelling syntheses using high pressure techniques (>300 bar). In principal, high pressures can be utilized for increasing reaction rates and minimizing the amounts of reagents. One problem with this approach is how to confine the labeled precursor in a small high-pressure reactor. Another problem is the construction of the reactor. If a common column type of reactor is used (i.e. a cylinder with tubing attached to each end), the gas-phase will actually become efficiently excluded from the liquid phase at pressurization. The reason is that the gas-phase, in contracted form, will escape into the attached tubing and away from the bulk amount of the liquid reagent. The cold-trap technique is widely used in the handling of 11 C-labelled precursors, particularly in the case of [ 11 C]carbon dioxide. The procedure has, however, only been performed in one single step and the labeled compound was always released in a continuous gas-stream simultaneous with the heating of the cold-trap. Furthermore, the volume of the material used to trap the labeled compound has been relative large in relation to the system to which the labeled compound has been transferred. Thus, the option of using this technique for radical concentration of the labeled compound and miniaturization of synthesis systems has not been explored. This is especially noteworthy in view of the fact that the amount of a 11 C-labelled compound usually is in the range 20-60 nmol. Recent technical development for the production and use of [ 11 C] carbon monoxide has made this compound useful in labeling synthesis. WO 02/102711 describes a system and a method for the production and use of a carbon-isotope monoxide enriched gas-mixture from an initial carbon-isotope dioxide gas mixture. [ 11 C] carbon monoxide may be obtained in high radiochemical yield from cyclotron produced [ 11 C] carbon dioxide and can be used to yield target compounds with high specific radioactivity. This reactor overcomes the difficulties listed above and is useful in synthesis of 11 C-labelled compounds using [ 11 C] carbon monoxide in palladium or selenium mediated reaction. With such method, a broad array of carbonyl compounds can be labeled (Kilhlberg, T.; Langstrom, B. J., Org. Chem. 1999, 9201-9205). The use of transition metal mediated reactions is, however, restricted by problems related to the competing β-hydride elimination reaction, which excludes or at least severely restricts utilization of organic electrophiles having hydrogen in β-position. Thus, a limitation of the transition metal mediated reactions is that most alkyl halides could not be used as substrates due to the β-hydride elimination reaction. One way to circumvent this problem is to use free-radical chemistry based on light irradiation of alkyl halides. However, this method gives poor results when weakly nucleophilic amines are used. Therefore, there is a need for a method in order to use photo-induced free radical carbonylation with weakly necleophilic amines to circumvent the problem with β-hydride elimination to complement the palladium mediated reactions and provide target structures to further increase the utility of [ 11 C] carbon monoxide in preparing useful PET tracers. Discussion or citation of a reference herein shall not be construed as an admission that such reference is prior art to the present invention. SUMMARY OF THE INVENTION The present invention provides a method for labeling synthesis, comprising: (a) providing a UV reactor assembly comprising a high pressure reaction chamber, a UV lamp and a concave mirror, wherein the high pressure reaction chamber having a window facing the concave mirror, a liquid inlet and a gas inlet in a bottom surface thereof, (b) reacting a solution of weakly nucleophilic amine with a metal base to improve the reactivity of said weakly nucleophilic amine, (c) adding a solution of akyl or aryl iodides to the solution of step (b) to give a reagent volume to be labeled, (d) introducing a carbon-isotope monoxide enriched gas-mixture into the reaction chamber of the UV reactor assembly via the gas inlet, (e) introducing at high-pressure said reagent volume into the reaction chamber via the liquid inlet, (f) turning on the UV lamp and waiting a predetermined time while the labeling synthesis occur, and (g) collecting the labeled amide from the reaction chamber. The present invention also provides a system for labeling synthesis, comprising: a UV reactor assembly comprising a high pressure reaction chamber, a UV lamp and a concave mirror, wherein the high pressure reaction chamber having a window facing the concave mirror, a liquid inlet and a gas inlet in a bottom surface thereof, wherein the concave mirror can focus the UV light from the UV lamp, and the focused light beam enters the window of the reaction chamber. The present invention further provides a method for the synthesis of labeled amides using photo-initiated carbonylation with [ 11 C] carbon monoxide using weakly nucleophilic amines treated with strong metal base and alkyl or aryl iodides. In yet another embodiment, the invention also provides [ 11 C]-labeled amides. In still another embodiment, the invention provides kits for use as PET tracers comprising [ 11 C]-labeled amides. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows a flow chart over the method according to the invention FIG. 2 is a schematic view of a carbon-isotope monoxide production and labeling-system according to the invention. FIG. 3 shows the main parts of the UV reactor assembly. FIG. 4 is the schematic diagram of the optical scheme of the UV reactor assembly. FIG. 5 is the cross-sectional view of the reaction chamber. FIG. 6 shows reaction chamber and its cooling jacket. FIGS. 7 a and 7 b show alternative embodiments of a reaction chamber according to the invention. DETAILED DESCRIPTION OF THE INVENTION The object of the invention is to provide a method and a system for production of and use of carbon-isotope monoxide in labeling synthesis that overcomes the drawbacks of the prior art devices. This is achieved by the method and system claimed in the invention. One advantage with such a method and system is that nearly quantitative conversion of carbon-isotope monoxide into labeled products can be accomplished. There are several other advantages with the present method and system. The high-pressure technique makes it possible to use low boiling solvents such as diethyl ether at high temperatures (e.g. 200° C.). The use of a closed system consisting of materials that prevents gas diffusion, increases the stability of sensitive compounds and could be advantageous also with respect to Good Manufacturing Practice (GMP). Still other advantages are achieved in that the resulting labeled compound is highly concentrated, and that the miniaturization of the synthesis system facilitates automation, rapid synthesis and purification, and optimization of specific radioactivity through minimization of isotopic dilution. Most important is the opening of completely new synthesis possibilities, as exemplified by the present invention. Embodiments of the invention will now be described with reference to the figures. The term carbon-isotope that is used throughout this application preferably refers to 11 C, but it should be understood that 11 C may be substituted by other carbon-isotopes, such as 13 C and 14 C, if desired. FIG. 1 shows a flow chart over the method according to the invention, which firstly comprises production of a carbon-isotope monoxide enriched gas-mixture and secondly a labeling synthesis procedure. More in detail the production part of the method comprises the steps of: Providing carbon-isotope dioxide in a suitable carrier gas of a type that will be described in detail below. Converting carbon-isotope dioxide to carbon-isotope monoxide by introducing said gas mixture in a reactor device which will be described in detail below. Removing traces of carbon-isotope dioxide by flooding the converted gas-mixture through a carbon dioxide removal device wherein carbon-isotope dioxide is trapped but not carbon-isotope monoxide nor the carrier gas, The carbon dioxide removal device will be described in detail below. Trapping carbon-isotope monoxide in a carbon monoxide trapping device, wherein carbon-isotope monoxide is trapped but not said carrier gas. The carbon monoxide trapping device will be described in detail below. Releasing said trapped carbon-isotope monoxide from said trapping device, whereby a volume of carbon-isotope monoxide enriched gas-mixture is achieved. The production step may further comprise a step of changing carrier gas for the initial carbon-isotope dioxide gas mixture if the initial carbon-isotope dioxide gas mixture is comprised of carbon-isotope dioxide and a first carrier gas not suitable as carrier gas for carbon monoxide due to similar molecular properties or the like, such as nitrogen. More in detail the step of providing carbon-isotope dioxide in a suitable second carrier gas such as He, Ar, comprises the steps of: Flooding the initial carbon-isotope dioxide gas mixture through a carbon dioxide trapping device, wherein carbon-isotope dioxide is trapped but not said first carrier gas. The carbon dioxide trapping device will be described in detail below. Flushing said carbon dioxide trapping device with said suitable second carrier gas to remove the remainders of said first carrier gas. Releasing said trapped carbon-isotope dioxide in said suitable second carrier gas. The labeling synthesis step that may follow the production step utilizes the produced carbon-isotope dioxide enriched gas-mixture as labeling reactant. More in detail the step of labeling synthesis comprises the steps of: Providing a UV reactor assembly comprising a UV lamp, a concave mirror and a high pressure reaction chamber having a liquid reagent inlet and a labeling reactant inlet in a bottom surface thereof. The UV reactor assembly and the reaction chamber will be described in detail below. Providing a reagent volume that is to be labeled. The reagent volume can be prepared in following steps: 1. Dissolve an akyl or aryl iodide in a solvent; 2. Dissolve a weakly nucleophilic amine in a solvent in a separate vessel; 3. Add sufficient amount of metal base to the solution of weakly nucleophilic amine to increase the reactivity of said weakly nucleophilic amine; 4. Mix solutions of step 1 and step 3 to form a reagent volume as late as possible before being introduced into the reaction chamber. A “weakly nucleophic amine” is defined as an amine having a decay correlated radiochemical yield of less than 5% when react with an akyl or aryl iodide and 11 CO in a reaction without metal base. Definition and examples of metal base will be provided below. Introducing the carbon-isotope monoxide enriched gas-mixture into the reaction chamber via the labeling reactant inlet. Introducing, at high pressure, said liquid reagent into the reaction chamber via the liquid reagent inlet. Turning on the UV lamp and waiting a predetermined time while the labeling synthesis occur. Collecting the solution of labeled amide from the reaction chamber. The step of waiting a predetermined time may further comprise adjusting the temperature of the reaction chamber such that the labeling synthesis is enhanced. FIG. 2 schematically shows a [ 11 C]carbon dioxide production and labeling-system according to the present invention. The system is comprised of three main blocks, each handling one of the three main steps of the method of production and labeling: Block A is used to perform a change of carrier gas for an initial carbon-isotope dioxide gas mixture, if the initial carbon-isotope dioxide gas mixture is comprised of carbon-isotope dioxide and a first carrier gas not suitable as carrier gas for carbon monoxide. Block B is used to perform the conversion from carbon-isotope dioxide to carbon-isotope monoxide, and purify and concentrate the converted carbon-isotope monoxide gas mixture. Block C is used to perform the carbon-isotope monoxide labeling synthesis. Block A is normally needed due to the fact that carbon-isotope dioxide usually is produced using the 14N(p,α) 11 C reaction in a target gas containing nitrogen and 0.1% oxygen, bombarded with 17 MeV protons, whereby the initial carbon-isotope dioxide gas mixture comprises nitrogen as carrier gas. However, compared with carbon monoxide, nitrogen show certain similarities in molecular properties that makes it difficult to separate them from each other, e.g. in a trapping device or the like, whereby it is difficult to increase the concentration of carbon-isotope monoxide in such a gas mixture. Suitable carrier gases may instead be helium, argon or the like. Block A can also used to change the pressure of the carrier gas (e.g. from 1 to 4 bar), in case the external system does not tolerate the gas pressure needed in block B and C. In an alternative embodiment the initial carbon-isotope dioxide gas mixture is comprised of carbon-isotope dioxide and a first carrier gas that is well suited as carrier gas for carbon monoxide, whereby the block A may be simplified or even excluded. According to a preferred embodiment ( FIG. 2 ), block A is comprised of a first valve V 1 , a carbon dioxide trapping device 8 , and a second valve V 2 . The first valve V 1 has a carbon dioxide inlet 10 connected to a source of initial carbon-isotope dioxide gas mixture 12 , a carrier gas inlet 14 connected to a source of suitable carrier gas 16 , such as helium, argon and the like. The first valve V 1 further has a first outlet 18 connected to a first inlet 20 of the second valve V 2 , and a second outlet 22 connected to the carbon dioxide trapping device 8 . The valve V 1 may be operated in two modes A, B, in mode A the carbon dioxide inlet 10 is connected to the first outlet 18 and the carrier gas inlet 14 is connected to the second outlet 22 , and in mode B the carbon dioxide inlet 10 is connected to the second outlet 22 and the carrier gas inlet 14 is connected to the first outlet 18 . In addition to the first inlet 20 , the second valve V 2 has a second inlet 24 connected to the carbon dioxide trapping device 8 . The second valve V 2 further has a waste outlet 26 , and a product outlet 28 connected to a product inlet 30 of block B. The valve V 2 may be operated in two modes A, B, in mode A the first inlet 20 is connected to the waste outlet 26 and the second inlet 24 is connected to the product outlet 28 , and in mode B the first inlet 20 is connected to the product outlet 28 and the second inlet 24 is connected to the waste outlet 26 . The carbon dioxide trapping device 8 is a device wherein carbon dioxide is trapped but not said first carrier gas, which trapped carbon dioxide thereafter may be released in a controlled manner. This may preferably be achieved by using a cold trap, such as a column containing a material which in a cold state, (e.g. −196° C. as in liquid nitrogen or −186° C. as in liquid argon) selectively trap carbon dioxide and in a warm state (e.g. +50° C.) releases the trapped carbon dioxide. (In this text the expression “cold trap” is not restricted to the use of cryogenics. Thus, materials that traps the topical compound at room temperature and release it at a higher temperature are included). One suitable material is porapac Q®. The trapping behavior of a porapac-column is related to dipole-dipole interactions or possibly Van der Waal interaktions. The said column 8 is preferably formed such that the volume of the trapping material is to be large enough to efficiently trap (>95%) the carbon-isotope dioxide, and small enough not to prolong the transfer of trapped carbon dioxide to block B. In the case of porapac Q® and a flow of 100 ml nitrogen/min, the volume should be 50-150 μl. The cooling and heating of the carbon dioxide trapping device 8 may further be arranged such that it is performed as an automated process, e.g. by automatically lowering the column into liquid nitrogen and moving it from there into a heating arrangement. According to the preferred embodiment of FIG. 2 block B is comprised of a reactor device 32 in which carbon-isotope dioxide is converted to carbon-isotope monoxide, a carbon dioxide removal device 34 , a check-valve 36 , and a carbon monoxide trapping device 38 , which all are connected in a line. In the preferred embodiment the reactor device 32 is a reactor furnace comprising a material that when heated to the right temperature interval converts carbon-isotope dioxide to carbon-isotope monoxide. A broad range of different materials with the ability to convert carbon dioxide into carbon monoxide may be used, e.g. zinc or molybdenum or any other element or compound with similar reductive properties. If the reactor device 32 is a zinc furnace it should be heated to 400° C., and it is important that the temperature is regulated with high precision. The melting point of zinc is 420° C. and the zinc-furnace quickly loses it ability to transform carbon dioxide into carbon monoxide when the temperature reaches over 410° C., probably due to changed surface properties. The material should be efficient in relation to its amount to ensure that a small amount can be used, which will minimize the time needed to transfer radioactivity from the carbon dioxide trapping device 8 to the subsequent carbon monoxide trapping device 38 . The amount of material in the furnace should be large enough to ensure a practical life-time for the furnace (at least several days). In the case of zinc granulates, the volume should be 100-1000 μl. The carbon dioxide removal device 34 is used to remove traces of carbon-isotope dioxide from the gas mixture exiting the reactor device 32 . In the carbon dioxide removal device 34 , carbon-isotope dioxide is trapped but not carbon-isotope monoxide nor the carrier gas. The carbon dioxide removal device 34 may be comprised of a column containing ascarite® (i.e. sodium hydroxide on silica). Carbon-isotope dioxide that has not reacted in the reactor device 32 is trapped in this column (it reacts with sodium hydroxide and turns into sodium carbonate), while carbon-isotope monoxide passes through. The radioactivity in the carbon dioxide removal device 34 is monitored as a high value indicates that the reactor device 32 is not functioning properly. Like the carbon dioxide trapping device 8 , the carbon monoxide trapping device 38 , has a trapping and a releasing state. In the trapping state carbon-isotope monoxide is selectively trapped but not said carrier gas, and in the releasing state said trapped carbon-isotope monoxide is released in a controlled manner. This may preferably be achieved by using a cold trap, such as a column containing silica which selectively trap carbon monoxide in a cold state below −100° C., e.g. −196° C. as in liquid nitrogen or −186° C. as in liquid argon, and releases the trapped carbon monoxide in a warm state (e.g. +50° C.). Like the porapac-column, the trapping behavior of the silica-column is related to dipole-dipole interactions or possibly Van der Waal interactions. The ability of the silica-column to trap carbon-isotope monoxide is reduced if the helium, carrying the radioactivity, contains nitrogen. A rationale is that since the physical properties of nitrogen are similar to carbon monoxide, nitrogen competes with carbon monoxide for the trapping sites on the silica. According to the preferred embodiment of FIG. 2 , block C is comprised of a first and a second reaction chamber valve V 3 and V 4 , a reagent valve V 5 , an injection loop 70 and a solvent valve V 6 , and the UV reactor assembly 51 which comprises a UV lamp 91 , a concave mirror 92 and a reaction chamber 50 . The first reaction chamber valve V 3 has a gas mixture inlet 40 connected to the carbon monoxide trapping device 38 , a stop position 42 , a collection outlet 44 , a waste outlet 46 , and a reaction chamber connection port 48 connected to a gas inlet 52 of the reaction chamber 50 . The first reaction chamber valve V 3 has four modes of operation A to D. The reaction chamber connection port 48 is: in mode A connected to the gas mixture inlet 40 , in mode B connected to the stop position 42 , in mode C connected to the collection outlet 44 , and in mode D connected to the waste outlet 46 . FIG. 3 is a diagram of UV reactor assembly 51 . It comprises of a UV lamp 91 , a concave mirror 92 , a reaction chamber 50 . In a preferred embodiment, it also includes a bench 93 and protective housing 94 , so that all parts located inside of the protective housing and mounted on the bench. In the most preferred embodiment, it further comprises a motor 95 , a magnet stirrer 96 , a magnet stirring bar 97 and a thermocouple 98 (see FIG. 5 ). In a preferred embodiment, all parts are mounted on a bench. They are shielded with a thin protective housing outside for protection against LV radiation. Compressed air is supplied through inlet attached to the top face of the housing to ventilate the device and to provide normal operation conditions for the LV lamp. The optical scheme is illustrated in FIG. 4 . A spherical concave mirror is used to collect the output of the arc and direct it onto the reactor cavity. The light source and reactor are displaced from the optical axis of the mirror so that the UV lamp does not block the light collected by the mirror. This also prevents the bulb from overheating. Distance between the reactor and the lamp is kept at minimum to ensure smallest arc image. The reaction chamber 50 (micro-autoclave) has a gas inlet 52 and a liquid inlet 54 , which are arranged such that they terminate at the bottom surface of the chamber. Gas inlet 52 may also be used as product outlet after the labeling is finished. During operation the carbon-isotope monoxide enriched gas mixture is introduced into the reaction chamber 50 through the gas inlet 52 , where after the liquid reagent at high pressure enters the reaction chamber 50 through the liquid inlet 54 . FIGS. 3 a and 3 b shows schematic views of two preferred reaction chambers 50 in cross section. FIG. 7 a is a cylindrical chamber which is fairly easy to produce, whereas the spherical chamber of FIG. 7 b is the most preferred embodiment, as the surface area to volume-ratio of the chamber is further minimized. A minimal surface area to volume-ratio optimizes the recovery of labeled product and minimizes possible reactions with the surface material. Due to the “diving-bell construction” of the reaction chamber 50 , both the gas inlet 52 and the liquid inlet 54 becomes liquid-filled and the reaction chamber 50 is filled from the bottom upwards. The gas-volume containing the carbon-isotope monoxide is thus trapped and given efficient contact with the reaction mixture. Since the final pressure of the liquid is approximately 80 times higher than the original gas pressure, the final gas volume will be less than 2% of the liquid volume according to the general gas-law. Thus, a pseudo one-phase system will result. In the instant application, the term “pseudo one-phase system” means a closed volume with a small surface area to volume-ratio containing >96% liquid and <4% gas at pressures exceeding 200 bar. In most syntheses the transfer of carbon monoxide from the gas-phase to the liquid phase will probably not be the rate limiting step. After the labeling is finished the labeled volume is nearly quantitatively transferred from the reaction chamber by the internal pressure via the gas inlet/product outlet 52 and the first reaction chamber valve V 3 in position C. In a specific embodiment, FIG. 5 shows a reaction chamber made from stainless steel (Valco™) column end fitting. It is equipped with sapphire window, which is a hard material transparent to short wavelength UV radiation. The window is pressed between two Teflon washers inside the drilled column end fitting to make the reactor tight at high pressures. Temperature measurement can be accomplished with the thermocouple 98 attached by solder drop to the outer side of the reactor. The magnet stirrer drives small Teflon coated magnet place inside the reaction chamber. The magnetic stirrer can be attached to the side of the reaction chamber in the assembly. Distance between the magnet stirrer and the reactor should be minimal. FIG. 6 illustrates a device used to remove excessive heat produced by the light source and keep the reaction chamber at constant temperature. Copper tube can be placed into the short piece of copper tube of larger diameter filled up with lead alloy. Hexagonal hole can be made to fit the reaction chamber nut tightly. To increase heat transfer between reactor and the thermostat, thermoconductive silicon grease can be used. The thermostat can then be connected to standalone water bath thermostat with rubber tubes. Referring back to FIG. 2 , the second reaction chamber valve V 4 has a reaction chamber connection port 56 , a waste outlet 58 , and a reagent inlet 60 . The second reaction chamber valve V 4 has two modes of operation A and B. The reaction chamber connection port 56 is: in mode A connected to the waste outlet 58 , and in mode B it is connected to the reagent inlet 60 . The reagent valve V 5 , has a reagent outlet 62 connected to the reagent inlet 60 of the second reaction chamber valve V 4 , an injection loop inlet 64 and outlet 66 between which the injection loop 70 is connected, a waste outlet 68 , a reagent inlet 71 connected to a reagent source, and a solvent inlet 72 . The reagent valve V 5 , has two modes of operation A and B. In mode A the reagent inlet 71 is connected to the injection loop inlet 64 , and the injection loop outlet 66 is connected to the waste outlet 68 , whereby a reagent may be fed into the injection loop 70 . In mode B the solvent inlet 72 is connected to the injection loop inlet 64 , and the injection loop outlet 66 is connected to the reagent outlet 62 , whereby reagent stored in the injection loop 70 may be forced via the second reaction chamber valve V 4 into the reaction chamber 50 if a high pressure is applied on the solvent inlet 72 . The solvent valve V 6 , has a solvent outlet 74 connected to the solvent inlet 72 of the reagent valve V 5 , a stop position 76 , a waste outlet 78 , and a solvent inlet 80 connected to a solvent supplying HPLC-pump (High Performance Liquid Chromatography) or any liquid-pump capable of pumping organic solvents at 0-10 ml/min at pressures up to 400 bar (not shown). The solvent valve V 6 , has two modes of operation A and B. In mode A the solvent outlet 74 is connected to the stop position 76 , and the solvent inlet 80 is connected to the waste outlet 78 . In mode B the solvent outlet 74 is connected to the solvent inlet 80 , whereby solvent may be pumped into the system at high pressure by the HPLC-pump. Except for the small volume of silica in the carbon monoxide trapping devise 38 , an important difference in comparison to the carbon dioxide trapping device 8 , as well as to all related prior art, is the procedure used for releasing the carbon monoxide. After the trapping of carbon monoxide on carbon monoxide trapping devise 8 , valve V 3 is changed from position A to B to stop the flow from the carbon monoxide trapping devise 38 and increase the gas-pressure on the carbon monoxide trapping devise 38 to the set feeding gas pressure (3-5 bar). The carbon monoxide trapping devise 38 is then heated to release the carbon monoxide from the silica surface while not significantly expanding the volume of carbon monoxide in the carrier gas. Valve V 4 is changed from position A to B and valve V 3 is then changed from position B to A. At this instance the carbon monoxide is rapidly and almost quantitatively transferred in a well-defined micro-plug into the reaction chamber 50 . Micro-plug is defined as a gas volume less than 10% of the volume of the reaction chamber 50 , containing the topical substance (e.g. 1-20 μL). This unique method for efficient mass-transfer to a small reaction chamber 50 , having a closed outlet, has the following prerequisites: A micro-column 38 defined as follows should be used. The volume of the trapping material (e.g. silica) should be large enough to efficiently trap (>95%) the carbon-isotope monoxide, and small enough (<1% of the volume of a subsequent reaction chamber 50 ) to allow maximal concentration of the carbon-isotope monoxide. In the case of silica and a reaction chamber 50 volume of 200 μl, the silica volume should be 0.1-2 μl. The dead volumes of the tubing and valve(s) connecting the silica column and the reaction chamber 50 should be minimal (<10% of the micro-autoclave volume). The pressure of the carrier gas should be 3-5 times higher than the pressure in the reaction chamber 50 before transfer (1 atm.). In one specific preferred embodiment specifications, materials and components are chosen as follows. High pressure valves from Valco®, Reodyne® or Cheminert® are used. Stainless steel tubing with o.d. 1/16″ is used except for the connections to the porapac-column 8 , the silica-column 38 and the reaction chamber 50 where stainless steel tubing with o.d. 1/32″ are used in order to facilitate the translation movement. The connections between V 1 , V 2 and V 3 should have an inner diameter of 0.2-1 mm. The requirement is that the inner diameter should be large enough not to obstruct the possibility to achieve the optimal flow of He (2-50 ml/min) through the system, and small enough not to prolong the time needed to transfer the radioactivity from the porapac-column 8 to the silica-column 38 . The dead volume of the connection between V 3 and the autoclave should be minimized (<10% of the autoclave volume). The inner diameter (0.05-0.1 mm) of the connection must be large enough to allow optimal He flow (2-50 ml/min). The dead volume of the connection between V 4 and V 5 should be less than 10% of the autoclave volume. The porapac-column 8 preferably is comprised of a stainless steel tube (o.d.=⅛″, i.d.=2 mm, 1=20 mm) filled with Porapac Q® and fitted with stainless steel screens. The silica-column 38 preferably is comprised of a stainless steel tube (o.d= 1/16″, i.d.=0.1 mm) with a cavity (d=1 mm, h=1 mm, V=0.8 μl) in the end. The cavity is filled with silica powder (100/80 mesh) of GC-stationary phase type. The end of the column is fitted against a stainless steel screen. It should be noted that a broad range of different materials could be used in the trapping devices. If a GC-material is chosen, the criterions should be good retardation and good peak-shape for carbon dioxide and carbon monoxide respectively. The latter will ensure optimal recovery of the radioactivity. Below a detailed description is given of a method of producing carbon-isotope using an exemplary system as described above. Preparations of the system are performed by the steps 1 to 5: 1. V 1 in position A, V 2 in position A, V 3 in position A, V 4 in position A, helium flow on with a max pressure of 5 bar. With this setting, the helium flow goes through the porapac column, the zinc furnace, the silica column, the reaction chamber 50 and out through V 4 . The system is conditioned, the reaction chamber 50 is rid of solvent and it can be checked that helium can be flowed through the system with at least 10 ml/min. UV lamp 91 is turned on. 2. The zinc-furnace is turned on and set at 400° C. 3. The porapac- and silica-columns are cooled with liquid nitrogen. At −196° C., the porapac- and silica-column efficiently traps carbon-isotope dioxide and carbon-isotope monoxide respectively. 4. V 5 in position A (load). The injection loop (250 μl), attached to V 5 , is loaded with the reaction mixture. 5. The HPLC-pump is attached to a flask with freshly distilled THF (or other high quality solvent) and primed. V 6 in position A. Production of carbon-isotope dioxide may be performed by the steps 6 to 7: 6. Carbon-isotope dioxide is produced using the 14N(p,α) 11 C reaction in a target gas containing nitrogen (AGA, Nitrogen 6.0) and 0.1% oxygen (AGA. Oxygen 4.8), bombarded with 17 MeV protons. 7. The carbon-isotope dioxide is transferred to the apparatus using nitrogen with a flow of 100 m/min. Synthesis of carbon-isotope may thereafter be performed by the steps 8 to 16 8. V 1 in position B and V 2 in position B. The nitrogen flow containing the carbon-isotope dioxide is now directed through the porapac-column (cooled to −196° C.) and out through a waste line. The radioactivity trapped in the porapac-column is monitored. 9. When the radioactivity has peaked, V 1 is changed to position A. Now a helium flow is directed through the porapac-column and out through the waste line. By this operation the tubings and the porapac-column are rid of nitrogen. 10. V 2 in position A and the porapac-column is warmed to about 50° C. The radioactivity is now released from the porapac-column and transferred with a helium flow of 10 ml/min into the zinc-furnace where it is transformed into carbon-isotope monoxide. 11. Before reaching the silica-column (cooled to −196° C.), the gas flow passes the ascarite-column. The carbon-isotope monoxide is now trapped on the silica-column. The radioactivity in the silica-column is monitored and when the value has peaked, V 3 is set to position B and then V 4 is set to position B. 12. The silica-column is heated to approximately 50° C., which releases the carbon-isotope monoxide. V 3 is set to position A and the carbon-isotope monoxide is transferred to the reaction chamber 50 within 15 s. 13. V 3 is set to position B, V 5 is set to position B, the HPLC-pump is turned on (flow 7 ml/min) and V 6 is set to position B. Using the pressurised THF (or other solvent), the reaction mixture is transferred to the reaction chamber 50 . When the HPLC-pump has reached its set pressure limit (e.g. 40 Mpa), it is automatically turned off and then V 6 is set to position A. 14. Motor 95 , magnetic stir 96 and magnet stirring bar 97 in reaction chamber 50 are turned on. 15. After a sufficient reaction-time (usually 5 min), V 3 is set to position C and the content of the reaction chamber 50 is transferred to a collection vial. 16. The reaction chamber 50 can be rinsed by the following procedure: V 3 is set to position B, the HPLC-pump is turned on, V 6 is set to position B and when maximal pressure is reached V 6 is set to position A and V 3 is set to position 3 thereby transferring the rinse volume to the collection vial. With the recently developed fully automated version of the reaction chamber 50 system according to the invention, the value of [ 11 C]carbon monoxide as a precursor for 11 C-labelled tracers has become comparable with [ 11 C]methyl iodide. Currently, [ 11 C]methyl iodide is the most frequently used 11 C-precursor due to ease in production and handling and since groups suitable for labeling with [ 11 C]methyl iodide (e.g. hetero atom bound methyl groups) are common among biologically active substances. Carbonyl groups, that can be conveniently labeled with [ 11 C]carbon monoxide, are also common among biologically active substances. In many cases, due to metabolic events in vivo, a carbonyl group may even be more advantageous than a methyl group as labeling position. The use of [ 11 C]carbon monoxide for production of PET-tracers may thus become an interesting complement to [ 11 C]methyl iodide. Furthermore, through the use of similar technology, this method will most likely be applicable for synthesis of 13 C and 14 C substituted compounds. The main advantage of the present invention is to overcome the limitations of radical-mediated reaction to synthesize 11 C-labeled amides using alkyl/aryl iodides and weakly nucleophilic amines as precursors. The levels specific radioactivity are high compared with alternative methods such as the use of Grignard reactions for preparation of [carbonyl- 11 C] amides. Amines used as precursors in the instant invention have a formula wherein R′ and R″ are independently H, linear or cyclic alkyl or substituted alkyl, aryl or substituted aryl, and may contain chloro or fluoro groups. Examples of weakly nucleophic amines applicable to the instant invention include diphenylamine, indole and 5H-Dibenzo[b,f]azepine. Metal base used in the instant invention is defined as MB, wherein M is selected from the list comprising Li, Na, K, Cs and Mg, and B can be alkyl, aryl, hydride, dicyclohexylamide, diisopropylamide, hexamethyldisilylamide or YMGX, wherein Y=alkyl, aryl and X=halogen (Cl, Br and I). Examples of metal base include alkyl lithium, lithium bis(trimethylsilyl)amide, sodium hydride and Na diisopropyl amide. Iodides used in this invention have a formula RI, where R is linear or cyclic alkyl or substituted alkyl, aryl or substituted aryl, and may contain chloro, fluoro groups. The resultant labeled amides have a formula wherein R, R′ and R″ are defined as above. They provide valuable PET tracers in various PET studies. In an embodiment of the present invention, it provides kits for use as PET tracers comprising [ 11 C]-labeled amides. Such kits are designed to give sterile products suitable for human administration, e.g. direct injection into the bloodstream. Suitable kits comprise containers (e.g. septum-sealed vials). The kits may optionally further comprise additional components such as radioprotectant, antimicrobial preservative, pH-adjusting agent or filler. By the term “radioprotectant” is meant a compound which inhibits degradation reactions, such as redox processes, by trapping highly-reactive free radicals, such as oxygen-containing free radicals arising from the radiolysis of water. The radioprotectants of the present invention are suitably chosen from: ascorbic acid, para-aminobenzoic acid (i.e. 4-aminobenzoic acid), gentisic acid (i.e. 2,5-dihydroxybenzoic acid) and salts thereof with a biocompatible. By the term “antimicrobial preservative” is meant an agent which inhibits the growth of potentially harmful micro-organisms such as bacteria, yeasts or moulds. The antimicrobial preservative may also exhibit some bactericidal properties, depending on the dose. The main role of the antimicrobial preservative(s) of the present invention is to inhibit the growth of any such micro-organism in the pharmaceutical composition post-reconstitution, i.e. in the radioactive diagnostic product itself. The antimicrobial preservative may, however, also optionally be used to inhibit the growth of potentially harmful micro-organisms in one or more components of the kit of the present invention prior to reconstitution. Suitable antimicrobial preservatives include: the parabens, i.e., ethyl, propyl or butyl paraben or mixtures thereof; benzyl alcohol; phenol; cresol; cetrimide and thiomersal. Preferred antimicrobial preservative(s) are the parabens. The term “pH-adjusting agent” means a compound or mixture of compounds useful to ensure that the pH of the reconstituted kit is within acceptable limits (approximately pH 4.0 to 10.5) for human administration. Suitable such pH-adjusting agents include pharmaceutically acceptable buffers, such as tricine, phosphate or TRIS [i.e. tris(hydroxymethyl)aminomethane], and pharmaceutically acceptable bases such as sodium carbonate, sodium bicarbonate or mixtures thereof. When the ligand conjugate is employed in acid salt form, the pH-adjusting agent may optionally be provided in a separate vial or container, so that the user of the kit can adjust the pH as part of a multi-step procedure. By the term “filler” is meant a pharmaceutically acceptable bulking agent which may facilitate material handling during production and lyophilisation. Suitable fillers include inorganic salts such as sodium chloride, and water soluble sugars or sugar alcohols such as sucrose, maltose, mannitol or trehalose. General reaction scheme for the synthesis of labeled amides are as illustrated below: wherein R, R′, R″ and MB are as defined above. * indicates the 11 C labeled position. EXAMPLES The invention is further described in the following examples which are in no way intended to limit the scope of the invention. Example 1 Precursors and Resultant Products The following experiments illustrate the present invention. Radical carbonylation using submicromolar amounts of [ 11 C]carbon monoxide is performed yielding labeled with the amides shown in Table 1 as target compounds. Weakly nucleophic amines and alkyl iodides used for the labeling are shown in List 1 and List 2 respectively. Labelled amides according to the instant invention is shown in List 3. {2-[4-(2-Methoxy-phenyl)-piperazin-1-yl]-ethyl}-pyridin-2-yl-amine WAY-100634 List 1. Weakly nucleophilic amine used in labeling. List 2. Iodides used as precursors in labeling. compound 4, * indicates 11 C labeled position [carbonyl- 11 C]Cyclohexanecarboxylic acid {2-[4-(2-methoxy-phenyl)-piperazin-1-yl]-ethyl}-pyridin-2-yl-amide WAY-100635 compound 5, * indicates 11 C labeled position [carbonyl- 11 C]N-{2-[4-(2-Methoxy-phenyl)-piperazin-1-yl]-ethyl}-2,2-dimethyl-N-pyridin-2-yl-propionamide WAY-100135 compound 6, * indicates 11 C labeled position [carbonyl- 11 C]Nonanoic acid {2-[4-(2-methoxy-phenyl)-piperazin-1-yl]-ethyl}-pyridin-2-yl-amide List 3. Labelled amides according to the instant invention. Initial experiments performed by the standard procedure described below afforded only 2% decay corrected radiochemical yield (determined by LC) of the 11 C-carbonyl labelled WAY-100635 and a number of radiolabelled by-products. The reactions were carried out in a 270 μl stainless steel reaction vessel equipped with a sapphire window. The reactor was filled with [ 11 C]carbon monoxide in helium. Then the solution of an alkyl iodide together with the amine was pressurized at 35 MPa and reaction mixture was irradiated with focused light from a medium pressure Hg lamp (400 W) during 400 s. After the synthesis the crude mixture was collected in a vial. The amount of [ 11 C]carbon monoxide consumed in the reaction was estimated by measurements of radioactivity before and after purge of the gas phase in the collection vial. A sample from the crude reaction mixture was withdrawn for HPLC analysis and the remaining material was purified by semi-preparative HPLC. In order to increase the reactivity of the amine it was treated with different strong bases before the reaction with [11C]carbon monoxide. NaHDMS provided the best radiochemical yield and highest conversion of [11C]carbon monoxide (Table 1, entry 5). Two related compounds were labelled with the same method: WAY-100135 and a nonanoyl analogue (Table 1, entries 6-8). TABLE 1 Trapping efficiency and radiochemical yields of 11 C-labeled amides. Conversion of carbon Entry Product Base monoxide, a % Yield, b % 1 WAY-100635 (4) t-BuLi 91 (94) 46 c (38 c ) 2 WAY-100635 (4) NaH 17  3 c 3 WAY-100635 (4) LDA 91 29 c 4 WAY-100635 (4) KHDMS 39  8 c 5 WAY-100635 (4) NaHDMS 91 (91) 62 (55) 6 WAY-100135 (5) NaHDMS 28  9 c 7   Octyl WAY (6) NaHDMS 41 12 8   Octyl WAY (6) LiHDMS 70 22 c a Decay-corrected, the fraction of radioactivity left in the crude product after purge with nitrogen. b Radiochemical yield; decay-corrected, calculated from the amount of radioactivity in the crude product before nitrogen purge, and the radioactivity of the LC purified product. c Radiochemical yield; decay-corrected, calculated from analytical HPLC. The labelled compounds were identified by HPLC retention times. Further the identity was checked with LC-MS. LC-MS chromatograms recorded at SIR M+1 m/z for each of the labelled compounds displayed peaks with the same retention time as chromatogram of corresponding reference. The reference compounds were prepared via alternative synthetic routes and characterized by NMR and MS. This work describes convenient one-pot synthesis of 5-HT-1A subtype serotonine receptor radioligand WAY-100635 starting from [ 11 C]carbon monoxide, cyclohexyl iodide and amine WAY-100634. This method may become a practical alternative to Grignard synthesis. Example 2 Experimental Setup [ 11 C]Carbon dioxide production was performed using a Scanditronix MC-17 cyclotron at Uppsala IMANET. The 14 N(p,α) 11 C reaction was employed in a gas target containing nitrogen (Nitrogen 6.0) and 0.1% oxygen (Oxygen 4.8) which was bombarded with 17 MeV protons. [ 11 C]Carbon monoxide was obtained by reduction of [ 11 C]carbon dioxide as described in the instant application. The syntheses with [ 11 C]carbon dioxide were performed with an automated module as part of the system “Synthia 2000”. Liquid chromatographic analysis (LC) was performed with a gradient pump and a variable wavelength UV-detector in series with a β + -flow detector. The following mobile phases were used: 25 mM potassium dihydrogenphosphate (A) and acetonitrile/H 2 O: 50/7 (B). For analytical LC, a C 18 , 4 μm, 250×4.6 mm ID column was used at a flow of 1.5 mL/min. For semi-preparative LC, a C 18 , 4 μm, 250×10 mm (i.d.), column was used at a flow of 4 mL/min. An automated synthesis system, Synthia was used for LC injection and fraction collection. Radioactivity was measured in an ion chamber, Veenstra Instrumenten by, VDC-202. A Philips HOK 4/120SE mercury lamp was used as UV radiation source. In the analysis of the 11 C-labeled compounds, unlabeled reference substances were used for comparison in all the LC runs. NMR spectra of synthesized compounds were recorded at 400 MHz for 1 H and at 100 MHz for 13 C, at 25° C. Chemical shifts were referenced to TMS via the solvent signals. LC-MS analysis was performed using a Micromass VG Quattro with electrospray ionization. A Beckman 126 pump, a CMA 240 autosampler were used. THF was distilled under nitrogen from sodium/benzophenone. Example 3 Preparation of [11C]-labeled Amides A capped vial (1 mL) was flushed with nitrogen and then was charged with an amine (15 μmol), THF (200 mL) and a base (15 μmol) was added to the solution. An organo iodide (50 μmol) was added to the solution ca. 7 min before the start of the synthesis. The resulting mixture was transferred into the micro-autoclave (270 μL), pre-charged with [ 11 C]carbon monoxide in He at ambient temperature. The autoclave was irradiated with a mercury lamp for 400 s. The crude reaction mixture was then transferred from the autoclave to a capped vial (1 mL) held under reduced pressure. After measurement of the radioactivity the vial was purged with nitrogen and the radioactivity was measured again. The crude product was diluted with acetonitrile (0.6 mL) and injected on the semi-preparative LC. Analytical LC and LC-MS were used to assess the identity and radiochemical purity of the collected fraction. SPECIFIC EMBODIMENTS, CITATION OF REFERENCES The present invention is not to be limited in scope by specific embodiments described herein. Indeed, various modifications of the inventions in addition to those described herein will become apparent to these skilled in the art from the foregoing description and accompanying figures. Such modifications are intended to fall within the scope of the appended claims. Various publications and patent applications are cited herein, the disclosures of which are incorporated by reference in their entireties.

Methods and reagents for photo-initiated carbonylation with carbon-isotope labeled carbon monoxide using weakly nucleophilic amines and alkyl/aryl iodides are provided. The resultant carbon-isotope labeled amides are useful as radiopharmaceuticals, especially for use in Positron Emission Tomography (PET). Associated kits for PET studies are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 14/152,172, filed Jan. 10, 2014 which is a continuation of U.S. patent application Ser. No. 13/581,861, filed Nov. 6, 2012 (now U.S. Pat. No. 8,646,927), which is the U.S. National Phase application of PCT/US2011/028069, filed Mar. 11, 2011 which is a continuation of U.S. application Ser. No. 12/947,899, filed Nov. 17, 2010 (now U.S. Pat. No. 8,764,225), which is a continuation of U.S. application Ser. No. 11/642,089, filed Dec. 20, 2006 (now U.S. Pat. No. 7,837,348) which is a continuation-in-part application of U.S. application Ser. No. 10/583,105, filed Apr. 23, 2007 (now U.S. Pat. No. 7,819,549), entitled “High Efficiency Light Source Using Solid-State Emitter And Down-Conversion Material,” which is the 371 National Phase of International Application No. PCT/US2005/015736, filed May 5, 2005, which claims the benefit of priority to U.S. Provisional Application Ser. No. 60/568,373, filed May 5, 2004 and to U.S. Provisional Application Ser. No. 60/636,123, filed Dec. 15, 2004. This application also claims priority to U.S. Provisional Application Ser. No. 61/339,958, filed Mar. 11, 2010. The disclosures of all of these applications are incorporated in their entirety by reference herein. FIELD OF THE INVENTION [0002] The present invention relates generally to solid-state lighting. Specifically, the present invention relates to highly efficient lighting fixtures using solid-state light (SSL) sources, optic elements, heat sinks, and a remote wavelength-converting material. BACKGROUND OF THE INVENTION [0003] Solid-state light (SSL) emitting devices, including solid-state light fixtures having light emitting diodes (LEDs) are extremely useful, because they potentially offer lower fabrication costs and long term durability benefits over conventional light fixtures, such as those that utilize incandescent and fluorescent lamps. Due to their long operation (burn) time and low power consumption, solid-state light emitting devices frequently provide a functional cost benefit, even when their initial cost is greater than that of conventional lamps. Because large scale semiconductor manufacturing techniques may be used, many solid-state light fixtures may be produced at extremely low cost. [0004] In addition to applications such as indicator lights on home and consumer appliances, audio visual equipment, telecommunication devices and automotive instrument markings, LEDs have found considerable application in indoor and outdoor informational displays. For example, LEDs may be incorporated into overhead or wall-mounted lighting fixtures, and may be designed for aesthetic appeal. [0005] With the development of efficient LEDs that emit blue or ultraviolet (UV) light, it has become feasible to produce LEDs that generate white light through wavelength conversion of a portion of the primary emission of the LED to longer wavelengths. Conversion of primary emissions of the LED to longer wavelengths is commonly referred to as down-conversion of the primary emission. This system for producing white light by combining an unconverted portion of the primary emission with the light of longer wavelength is well known in the art. Other options to create white light with LEDs include mixing two or more colored LEDs in different proportions. For example, it is well known in the art that mixing red, green and blue (RGB) LEDs produces white light. Similarly, mixing RBG and amber (RGBA) LEDs, or RGB and white (RGBW) LEDs, are known to produce white light. [0006] Recent studies have determined that the heat generated from LEDs decreases overall light emission and bulb durability. More particularly, the LED device becomes less efficient when heated to a temperature greater than 100° C., resulting in a declining return in the visible spectrum. Extended operation, and the resulting exposure to high heat, also reduces the effective life of the LEDs. Additionally, the intrinsic wavelength-conversion efficiency for some down conversion phosphors also drops dramatically as the temperature increases above approximately 90° C. threshold. [0007] The amount of light emission directed into the particular environment may be increased by the use of reflective surfaces, which is also well known in the art. Reflective surfaces have been used to direct light from the LED to the wavelength-conversion material and/or to reflect down converted light which is generated from the wavelength-conversion material. Even with these improvements, the current state of the art LED technology is inefficient in the visible spectrum. The light output for a single LED is below that of traditional light fixtures such as those which utilize incandescent lamps, which are approximately 10 percent efficient in the visible spectrum. To achieve comparable light output power density to current light fixture technology utilizing incandescent lamps, an LED device often requires a larger LED or a design having multiple LEDs. However, designs incorporating a larger LED or multiple LEDs have been found to present their own challenges, such as heat generation and energy utilization. SUMMARY OF INVENTION [0008] To meet this and other needs, and in view of its purpose, the present invention provides a scattered photon extraction light fixture including an optic element having a first surface and at least one substantially transparent sidewall extending from the first surface; a light source for emitting short wavelength radiation, the light source disposed at an end of the at least one substantially transparent sidewall opposite the first surface of the optic element; a wavelength-conversion material, disposed on the first surface of the optic element, for receiving and down converting at least some of the short wavelength radiation emitted by the light source and back transferring a portion of the received and down converted radiation; and one or more reflectors positioned opposite the wavelength-conversion material, such that the light source is positioned between the wavelength-conversion material and the reflectors, for reflecting at least some of the radiation extracted from the optic element through the at least one substantially transparent sidewall; wherein the at least one substantially transparent sidewall is connected at one end to the first surface containing the wavelength-conversion material and at another end to the light source, and wherein the substantially transparent sidewall is configured to pass radiation back-transferred from the wavelength-conversion material outside of the light emitting apparatus. [0009] The light fixture may further include a wavelength-converting material disposed on at least one or more other walls, such as one or more transparent sidewalls, of the optic element. Similarly, the light fixture may further include a heat sink affixed or adjacent to the light source. In some embodiments, the heat sink may be affixed on one side to at least one substantially transparent sidewall and on another side to one or more reflectors. The light fixtures of the present invention may be, for example, extruded or revolved light emitting fixtures. The light fixtures may also include one or more suspension mechanisms for installation, for example, to a wall, as in a wall-mounted light fixture, or to a ceiling, as in a suspended light fixture. The light source may be at least one semiconductor light emitting diode, such as a light emitting diode (LED), a laser diode (LD), or a resonant cavity light emitting diode (RCLED). Additionally or alternatively, the light source may be an array of more than one light emitters, such as an array of LEDs. A number of different types of LEDs may be employed as the light source. For example, when an array is used as the light source, the array may include one or more LEDs of the same or of different types. The light sources may be selected to improve energy efficiency, control the color qualities of the emitted light, or for a number of other reasons, such as aesthetics. The wavelength-converting material may be include one or more materials, such as phosphors, quantum dots, quantum dot crystals, and quantum dot nano crystals, and mixtures thereof. [0010] In another embodiment, the present invention provides an extruded scattered photon extraction light fixture including a light source for emitting short wavelength radiation, the light source comprising one or more light emitters; an elongated tube optic element having at least one substantially transparent surface; a wavelength-conversion material, disposed on or integrated with at least one surface of the optic element and remote from the light source, for receiving and down converting at least some of the short wavelength radiation emitted by the light source and back transferring a portion of the received and down converted radiation; and one or more reflectors positioned opposite the wavelength-conversion material, such that the light source is positioned between the wavelength-conversion material and the reflectors, for reflecting at least some of back transferred portion of the received and down converted radiation; wherein the light fixture is configured such that some radiation may be reflected back towards the light source as unconverted light radiation, some light may be transferred through the wavelength-conversion material without being converted, and some radiation is converted and may be forward transferred or back transferred by the wavelength-conversion material; and wherein the light fixture is configured to capture substantially all of the forward transferred and the back transferred converted light by the arrangement of the light source, optic elements, and reflectors. [0011] In yet another embodiment, the present invention provides a scattered photon extraction light fixture including a light source for emitting short wavelength radiation, the light source comprising one or more light emitters, affixed to a first optic element; a wavelength-conversion material, disposed on or integrated with a second optic element, for receiving and down converting at least some of the short wavelength radiation emitted by the light source and back transferring a portion of the received and down converted radiation; and a reflective surface affixed at one side to the first optic element to form a reflective enclosure containing therein the second optic element and the wavelength-conversion material, for reflecting at least some of back transferred portion of the received and down converted radiation; wherein the second optic element and wavelength-conversion material are suspended within the reflective surface and remote from the light source. [0012] In still another embodiment, the present invention provides a scattered photon extraction light system including a plurality of light emitting fixtures. Each of the plurality of light emitting fixtures includes an optic element having a first surface and at least one substantially transparent sidewall extending from the first surface; a light source for emitting short wavelength radiation, the light source disposed at an end of the at least one substantially transparent sidewall opposite the first surface of the optic element; a wavelength-conversion material, disposed on the first surface of the optic element, for receiving and down converting at least some of the short wavelength radiation emitted by the light source and back transferring a portion of the received and down converted radiation; and one or more reflectors positioned opposite the wavelength-conversion material, such that the light source is positioned between the wavelength-conversion material and the reflectors, for reflecting at least some of the radiation extracted from the optic element through the at least one substantially transparent sidewall; wherein the at least one substantially transparent sidewall is connected at one end to the first surface containing the wavelength-conversion material and at another end to the light source, and wherein the substantially transparent sidewall is configured to pass radiation back-transferred from the wavelength-conversion material outside of the light emitting fixture. [0013] In a further embodiment, the present invention provides a scattered photon extraction light fixture including an optic element having a first surface with two opposite edges and one or more secondary surfaces, wherein the one or more secondary surfaces are tangentially or perpendicularly connected at each edge of the first surface; one or more light emitters for emitting short wavelength radiation, the one or more light emitters disposed on the one or more secondary surfaces of the optic element; a wavelength-conversion material, disposed on the first surface of the optic element, for receiving and down converting at least some of the short wavelength radiation emitted by the emitters and forward transferring a portion of the received and down converted radiation; and one or more reflectors positioned opposite the one or more light emitters, such that the wavelength-conversion material is positioned between the one or more light emitters and the reflectors, for reflecting at least some of the forward transferred radiation through the optic element; wherein the one or more secondary surfaces are each connected at one end to the first surface containing the wavelength-conversion material and at another end to the one or more reflectors, and wherein the one or more secondary surfaces are configured to pass radiation back-transferred from the wavelength-conversion material outside of the light emitting fixture. [0014] The wavelength-conversion material, in the embodiments of the present invention, is disposed remotely, i.e., away from the light source(s). One or more wavelength-converting materials are used to absorb radiation in one spectral region and emit radiation in another spectral region, and the wavelength-converting material can be either a down-converting or an up-converting material. Multiple wavelength-converting materials are capable of converting the wavelength emitted from the light source to the same or different spectral regions. The wavelength-conversion materials may be mixed together or employed as individual layers. By capturing both the forward transferred portion and the back transferred portion of the down-converted light, system efficiency may be improved. Similarly, the position of the down-conversion material and the reflector, when one or more reflectors are utilized, may be adjusted to ensure that light from the light source impinges the down-conversion material uniformly to produce a uniform white light and allowing more of the light to exit the device. Heat sinks may be utilized to reduce and/or redistribute heat at the light source(s). At the same time, positioning the down-conversion material remote from the light source prevents light feedback back into the light source. As a result, the heat at the light source is further minimized and results in improved light output and life. All of these structural parameters and features enable increased light production, enhanced lighting efficiency, and improved energy utilization in comparison to known technologies. BRIEF DESCRIPTION OF THE DRAWINGS [0015] The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following Figures: [0016] FIG. 1 is an illustration of a method of producing visible light using a solid-state light emitting diode (LED) and a wavelength-converting material according to an exemplary embodiment of the present invention; [0017] FIG. 2( a ) is an illustration of a solid-state light source light fixture, in accordance with one embodiment of the present invention; [0018] FIG. 2( b ) illustrates a cross-sectional view of the solid-state light source light fixture shown in FIG. 2 ; [0019] FIG. 2( c ) illustrates an expanded view of FIG. 2( b ) showing the heat sink and the solid-state light emitting diode (LED); [0020] FIG. 3 is an illustration of a solid-state light source light fixture, in accordance with another embodiment of the present invention; [0021] FIGS. 4( a )- 4 ( f ) illustrate cross-sectional views of other embodiments of the present invention which include one or more light sources, wave-length conversion materials, heat sinks, and optic elements; [0022] FIGS. 5( a )- 5 ( d ) illustrate cross-sectional views of other embodiments of one or more light sources, wave-length conversion materials, heat sinks, and optic elements, in accordance with other embodiments of the present invention; [0023] FIGS. 6( a )- 6 ( c ) illustrate a cross-sectional view of one or more light sources, wave-length conversion materials, heat sinks, and optic elements, when combined with a reflector, in accordance with other embodiments of the present invention; [0024] FIG. 7( a ) illustrates a wall-mounted lighting fixture according to an embodiment of the present invention; [0025] FIG. 7( b ) illustrates the lighting fixture of FIG. 7( a ) configured as a suspension from a ceiling, in accordance with another embodiment of the present invention; [0026] FIG. 7( c ) illustrates a cross-sectional view of the lighting fixtures shown in FIGS. 7( a ) and 7 ( b ); [0027] FIG. 7( d ) illustrates an expanded view of FIG. 7( c ) showing the heat sink, optic elements, and the solid-state light emitting diode (LED); [0028] FIG. 8( a ) illustrates a lighting fixture according to another embodiment of the present invention; [0029] FIG. 8( b ) illustrates a cross-sectional view of the lighting fixture shown in FIG. 8( a ), according to an embodiment of the present invention; [0030] FIG. 8( c ) illustrates a variation on the lighting fixture shown in FIGS. 8( a ) and 8 ( b ) which employs a compound reflector, according to another embodiment of the present invention; [0031] FIGS. 9( a )- 9 ( b ) illustrate lighting systems, according to another embodiment of the present invention, which employ multiple lighting fixtures; [0032] FIG. 10( a ) illustrates a lighting fixture similar to that shown in FIG. 2( a ) but without reflectors; [0033] FIG. 10( b ) illustrates the results of a ray tracing computer simulation showing the light output of the lighting fixture shown in FIG. 10( a ). DETAILED DESCRIPTION OF THE INVENTION [0034] Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. [0035] In U.S. Pat. No. 7,750,359, the inventors of the present invention have previously discovered the use of wavelength-converting materials to produce a broad bandwidth light having the desired chromaticity value and luminous efficacy while increasing the color rendering index (CRI) and lowering the correlated color temperature (CCT) of the output light, and increasing the efficiency of the device. In International Publication No. WO 2010/144572, the inventors of the present invention discovered and disclosed the benefits obtained by moving the wavelength-converting material to be remote, i.e., away, from the light source. By moving the wavelength-converting material away from the light source, more of the converted light can be extracted and the efficacy of the light device can be improved. Additional benefits were discovered utilizing a heat sink adjacent to, and/or integrated with, the light source. This method of producing light was described as a scattered photon extraction (SPE) technique. The SPE technique was found to increase light production, improve heat dissipation, and result in prolong light device durability and life span. These references, which utilized the SPE technique in an SSL-based lamp bulb as a replacement bulb for incandescent lamps, are incorporated herein by reference in their entirety. [0036] The inventors have now discovered that the SPE technique can be utilized to produce highly efficient lighting fixtures and lighting systems. Existing fixtures which utilize light emitting diode (LED) chips for general lighting applications have been found to have lower luminous output when compared with traditional light sources. To overcome this deficiency, existing LED-based fixtures have utilized arrays of LEDs to achieve the required light level on the target surfaces. Existing methods thus result in increased costs, higher energy consumption, and additional thermal management issues, among other disadvantages. The lighting fixtures of the present invention, which utilize the SPE technique and, optionally, structured optical elements, are able to produce increased light emission using fewer LEDs and less electrical energy. The lighting fixtures of the present invention also potentially reduce manufacturing and operation costs. [0037] The present invention addresses these problems by utilizing the SPE technique, which positions the light source at a point away from the wavelength-converting material. One or more optic elements can be positioned between the light source and the wavelength-converting material. Additionally, heat sinks and reflectors may be utilized in various configurations. The light source may be at least one semiconductor light emitting diode, such as a light emitting diode (LED), a laser diode (LD), or a resonant cavity LED (RCLED). Embodiments of the present invention may utilize a single SSL source, such as a single LED, or may include multiple SSL sources (i.e., a plurality of LEDs in an array) as the light source. As known in the art, a number of different types of LEDs may be employed as the light source. For example, when an array is used as the light source, the array may include one or more LEDs of the same or of different types. The light sources may be selected to improve energy efficiency, control the color qualities of the emitted light, or for a number of other reasons, such as aesthetics. The light source may be coupled to a heat sink, with at least a portion of the heat sink open to the environment to promote the dissipation of heat. The heat sink functions as a heat dissipation element for the light source, enabling heat to be drawn away from the light source. The heat sink may also provide mechanical support to the light source. For example, the heat sink may be substantially affixed to the optic element and coupled to the light source residing within the optic element. This coupling effectively retains the light source within the optic element. The heat sink may additionally be substantially affixed to one or more reflectors. These structural features of the present invention enable the SSL-based lighting fixture to have very high luminous efficacy values and produce light levels similar to, or greater than, traditional lighting fixtures such as fluorescent or incandescent lighting fixtures. The configuration of the present invention, and the utilization of the SPE technique, also prolonging the life span durability of the SSL-based light source. [0038] The use of wavelength-converting materials aids in the production of light that is aesthetically similar to that which is produced by traditional light fixtures, such as those which utilize incandescent A-lamps. As described above, the wavelength-converting material of the present invention may be composed of one or more materials adapted to absorb radiation in one spectral region and emit radiation in another spectral region, and the materials can be either a down-converting or an up-converting material. As such, embodiments of the present invention may incorporate wavelength-converting materials that are down-converting, up-converting, or both. It will be appreciated that the terms “down conversion,” “down converting,” and “down-converted” refer to materials which are adapted to absorb radiation in one spectral region and emit radiation in another spectral region. Accordingly, the term “down conversion material” is defined as materials that can, through their composition, absorb radiation in one spectral region and emit it in another spectral region. [0039] As light emitted from the light source reaches the wavelength-converting material, the wavelength-converting material absorbs the wavelength light and emits converted light. For example, when the wavelength-converting material includes down-converting material, the down-converting material absorbs short wavelength light and emits down converted light. The emitted down converted light may travel in all directions (known as a Lambertian emitter), and therefore, a portion of the down converted light travels upwards while another portion travels downwards. The light that goes upwards (or outwards) from the down conversion material is the forward transmitted portion of the light and the light that comes downwards towards the light source is the back transmitted portion. This is explained further below with reference to FIG. 1 . [0040] The fixtures of the present invention implement the remote wavelength-conversion concept associated with the SPE technique. In a system employing a remote down-conversion material, short wavelength radiant energy from the light source is emitted towards a down-conversion material which is positioned away from the light source. At least a portion of the radiant energy hitting the down-conversion material is down converted to a longer wavelength radiation and, when both radiations mix, results in a white light similar to the light produced by a traditional light fixture. The wavelength-conversion material may be composed of one or more down-converting materials adapted to absorb radiation in one spectral region and emit radiation in another spectral region. The wavelength-conversion materials may be mixed together or employed as individual layers. Multiple wavelength-converting materials are capable of converting the wavelength emitted from the light source to the same or different spectral regions. Accordingly, the wavelength-converting materials may comprise one or more down-converting materials, up-converting materials, or both, which may be selected to produce the desired light output and color rending properties. [0041] FIG. 1 shows a method of producing visible light using a solid-state light emitting diode (LED) 102 and a wavelength-converting material 104 , according to an exemplary embodiment of the present invention. As shown, emitted light radiation 100 from LED 102 hits wavelength-converting material 104 . Some of the emitted light radiation 100 from the LED 102 is reflected by the wavelength-converting material 104 as back transferred unconverted radiation 106 . Another portion of the emitted light radiation 100 from the LED 102 is converted by the wavelength-converting material 104 and emitted rearward as back transferred converted radiation 118 . Some of the emitted light radiation 100 from the LED 102 is passed through the wavelength-converting material 104 as forward transferred unconverted radiation 108 , while some is passed through as forward transferred converted radiation 114 . Furthermore, the wavelength-converting material 104 may emit forward scattered converted radiation 116 and back scattered converted radiation 120 . The back scattered converted radiation 120 and back transferred converted radiation 118 are collectively considered back transferred wavelength-converted radiation 112 , while the forward scattered converted radiation 116 and the forward transferred converted radiation 114 are collectively considered forward transferred wavelength-converted radiation 110 . Use of the SPE technique, which positions the light source remote from the wavelength-converting material, enables improved extraction of the reflected unconverted 106 and transferred unconverted 108 photons, reflected converted 118 and transferred converted 114 photons, and forward scattered converted 116 and back scattered converted 120 radiation converted by the wavelength-converting material 104 . [0042] An optic element may occupy the space separating the LED and the wavelength-converting material. In some embodiments, an optic element may be affixed at one end to the LED light source and at another end to the wavelength-converting material. The optic element may take any three-dimensional geometric shape such as, for example, spherical, parabolic, conical, and elliptical. The optic element may also be described as having a cross-sectional shape from the group consisting of circular, triangular, hexagonal, trapezoidal, semicircular, and elliptical, among others. The optic element may be a substantially transparent and light transmissive medium such as, for example, air, glass, or an acrylic. One or more reflectors may be utilized to receive and reflect light emitted by the light source and down-converted by the down-conversion material (i.e., transferred light). The reflector may take any geometric shape such as, for example, spherical, parabolic, conical, and elliptical, and may be comprised of a variety of reflective surfaces known in the art. Additionally, the reflectors may be single units or compound units which include multiple reflective surfaces each having their own geometric shape, transmissiveness, and material composition. For example, the reflectors may be aluminum, plastic with a vaporized aluminum reflective layer, or any other kind of reflective surface. The reflector is positioned to reflect the down-converted light and may be separate from, or adjacent to, the down-conversion material. More than one reflector may be utilized, separately or as part of a compound reflector having multiple geometric configurations, in some embodiments. [0043] In some embodiments of the present invention, the reflector may be an optic element, such as a glass, that has been treated to impart reflective characteristics to the optic element. For example, the reflector may be an optic element upon which a thin film has been deposited or otherwise applied. Such reflectors are known in the art as dichroic filters, thin-film filters, or interference filters, and are often used to selectively pass light of a small range of colors while reflecting other colors. By comparison, dichroic mirrors tend to be characterized by the color(s) of light that they reflect, rather than the color(s) they pass. For simplicity, reflectors treated in this way are referred to collectively herein as “dichroic reflectors” as they may selectively, and concurrently, allow some light to pass while reflecting other light. Such dichroic reflectors may be selective, for example, for particular wave-lengths, heat, light, or for other characteristics of the radiation emitted by the light source, as is known in the art. The reflectors and optic elements of the present invention can have varying degrees of transmissiveness, i.e., they can be chosen to permit or reflect any range of radiation. For example, the optic elements may be entirely translucent and permit all light radiation to pass through. As is known to one having ordinary skill in the art, however, even entirely translucent optic elements may have some de minimis amount of reflective characteristics (e.g., clear glass has been found to reflect about 4% of light radiation) which is thought to be intrinsic of the optic element. Alternatively, the optic element may be entirely reflective and not permit any light radiation to pass through. Additionally, the optic elements and reflectors of the present invention may be prepared such that they have some portions with a particular amount of transmissiveness and other portions that permit or reflect a different amount of light radiation. Accordingly, each optic element or reflector may possess the same level of transmissiveness throughout or have different portions with varying levels of transmissiveness. Any range of transmissiveness of the optic element can be enabled by a number of means known in the art. [0044] In at least one embodiment of the present invention, the wavelength-conversion material is applied to, and contained on, the optic element or reflector using conventional techniques known in the art. In another embodiment, the wavelength-conversion material, such as a down-converting material, is integrated into the optic element or reflector. For example, an acrylic optic element may be fabricated which incorporates down-converting materials, such as phosphors, during the acrylic fabrication process, thereby producing an integrated down-conversion optic element. [0045] As detailed above with regard to FIG. 1 , the wavelength-conversion material may transmit, convert, or reflect light radiation. Some light radiation may be reflected back towards the light source as unconverted light radiation. The converted light may be forward transferred or back transferred. Additionally, some light may be transferred through the wavelength-conversion material without being converted (i.e., unconverted transmitted radiation). By capturing both the forward transferred portion and the back transferred portion of the down-converted light, system efficiency is improved. Similarly, the position of the down-conversion material and the reflector, when one or more reflectors are utilized, may be adjusted to ensure that light from the light source impinges the down-conversion material uniformly to produce a uniform white light and allowing more of the light to exit the device. At the same time, positioning the down-conversion material remote from the light source prevents light feedback back into the light source. As a result, the heat at the light source is further minimized and results in improved light output and life. All of these structural parameters and features enable increased light production, enhanced lighting efficiency, and improved energy utilization in comparison to known technologies. [0046] The solid-state light emitting device of the present invention may further include other components that are known in the art. For example, the SSL device may further include an electronic driver. Most SSL sources are low voltage direct current (DC) sources. Therefore an electronic driver is needed to condition the voltage and the current for use in the SSL-based light fixture. Alternatively, there are several alternating current (AC) SSL sources, such as AC-LEDs sold under trade name of “Acriche” by Seoul Semiconductor, Inc. of Seoul, South Korea. In these cases the SSL source (e.g., the LED or LED array) can be directly connected to the AC power available from the grid. Thus embodiments of the present invention may optionally include an electronic driver, at least a portion of which is inside the base of the light fixture, depending on the type of SSL source employed in the SSL-based light fixture. The present invention may further include at least one electronic conductor such as a connection wire. The electronic conductor may be disposed within the optic element to couple electrical current between the light fixture base and the light source. [0047] The light fixtures of the present invention may be utilized in any arrangement. For example, at least one embodiment of the present invention is a suspended or overhead light fixture. In such an embodiment, the light fixture may have one or more suspension mechanisms such as suspension rods, cables, or flanges. In another embodiment of the present invention, the light fixture is a wall-mounted light fixture. In such an embodiment, the light fixture may be mounted horizontally, vertically, or in any other fashion necessary to achieve the desired aesthetic and light output. In a further embodiment, the present invention is a system which includes one or more light fixtures. In such an embodiment, the light system may include a number of similar light fixtures or different light fixtures. One or more embodiments of the present invention may be configured to be suspended, wall-mounted, or both. For example, some embodiments of the present invention may be configured to work as both an overhead suspended light fixture or as a wall-mounted light fixture, with the suspension mechanisms and other components able to accommodate either configuration. Additionally, depending on the amount of illumination desired in the lighted area and on other factors, such as visual aesthetics, the embodiments of the present invention may be installed with the optic elements or reflectors pointing towards, or away from, the lighted area. These embodiments may be better understood in view of the figures, which are described below. [0048] FIG. 2( a ) is an illustration of a suspended or overhead solid-state light source light fixture, in accordance with one embodiment of the present invention. The suspended light fixture shown in FIG. 2( a ) is considered to be an extruded light fixture configuration, because the cross-sectional profile of the light fixture is substantially uniform along its horizontal axis. The term “extruded” is not intended to confine this embodiment of the present invention to any specific manufacturing process, such as an extrusion process, or to the result thereof. Instead, the extruded SPE light fixture of the present invention and its individual components may be manufactured by a number of known methods. The term “extruded” is used herein to instead refer to the configuration of the SPE light fixture which has a fixed cross-sectional profile but elongated side. Of course, other embodiments may show variations in the cross-sectional profile along the horizontal axis. As shown, the light source of the light fixture includes a plurality of emitters in an LED array 212 . The LED array 212 is positioned within an angle of a triangular cross-section optic element 206 having a concave surface remote from the light source. The LED array emits light radiation downwards toward the concave surface of the optic element, upon which a wavelength-converting material 204 is deposited. The light fixture further includes two parabolic reflectors 208 , which are positioned above the optic element 206 and the LED array 212 . The reflectors reflect light, which has been emitted by the LED array and down-converted and back transferred towards the reflectors, to the desired environment, i.e., a lighted area. This embodiment is further detailed in FIG. 2( b ), which illustrates a cross-sectional view of the solid-state light source light fixture shown in FIG. 2( a ). As shown, the LED array (which is shown in this view as one LED emitter 202 ) emits light radiation downwards towards a wavelength-conversion material 204 which includes a down-converting material. The wavelength-conversion material 204 is deposited on a concave surface of the triangular cross-section optic element 206 . A wavelength-converting material layer may also be coated on the other walls of the optics, if necessary for the particular light fixture configuration, light efficiency, and output. Some of the emitted light radiation 214 is down-converted and transferred forward, as forward transferred light 220 , through the concave surface of the optic element 206 . Some of the emitted light radiation 214 is down-converted and transferred rearward, as back transferred light 222 , through the side walls of the optic element 206 towards the reflectors 208 , where the converted light radiation is reflected. In the illustrated embodiment, reference numbers 214 , 220 , and 222 identify light beams, not physical elements, and are not claimed components of the invention. [0049] The direction of light rays impinging on the reflector is desirably in the same direction as light rays that have been transmitted through the down conversion layer. Consequently, the total light output of the fixture may be a combination of light transmitted through the down-conversion material and back transferred rays. However, depending on the reflector size, geometric shape, and distance from the optical element, some back transferred rays from the wavelength-converting material may impinge on the ceiling or walls without hitting the reflector. Such upward rays would be useful for an indirect-direct type light fixture, which will result in an increased illumination of the upper space of the room. [0050] The wavelength-converting material which is deposited on the concave surface of the optic element, in this embodiment, may be enclosed by the optic element to prevent detrimental dust accumulating which could decrease the overall light output of the fixture over time. As stated above, a wavelength-converting material is a material that absorbs radiation in one spectral region and emits radiation in another spectral region. In an exemplary embodiment, wavelength-converting material may comprise a single wavelength-converting material. In an alternative embodiment, the wavelength-converting material may comprise more than one wavelength-converting materials. Multiple wavelength-converting materials are capable of converting the wavelength emitted from the emitters to the same or different spectral regions. In exemplary or alternative embodiments, the wavelength-converting material may comprise one or more phosphors such as yttrium aluminum garnet doped with cerium (YAG:Ce), strontium sulfide doped with europium (SrS:Eu), YAG:Ce phosphor doped with europium; YAG:Ce phosphor plus cadmium selenide (CdSe) or other types of quantum dots created from other materials including lead (Pb) and silicon (Si); among others. In an alternative embodiment, the phosphor layer may comprise other phosphors, quantum dots, quantum dot crystals, quantum dot nano crystals, or other down-conversion materials. The wavelength-converting material may be a down-conversion crystal instead of powdered material mixed with a binding medium. The wavelength-converting material layer may include additional scattering particles, such as micro spheres, to improve mixing of light of different wavelengths. In an alternative embodiment, the wavelength-converting material may be comprised of multiple continuous or discrete sub-layers, each containing a different wavelength-converting material. Wavelength-converting materials may be formed by, for example, mounted, coated, deposition, stenciling, screen printing, and any other suitable technique. Wavelength-converting material may be formed partially on one wall of the optics. All of the embodiments disclosed in this application may use any of the phosphors described herein. [0051] Additional benefits can be achieved through the use of a heat sink. The embodiment shown in FIGS. 2( a )- 2 ( c ) is a suspended or overhead light fixture, which is affixed to a surface by one or more suspension mechanisms. For example, suspension wires or rods (hollow or solid) may be used to hang the light fixture. The suspension mechanisms may also include power cords, control wires, or other aspects which are necessarily included in light fixtures. Power and control wires for the light fixture may be connected along with the suspension wires or inside the rods. [0052] FIG. 2( c ) illustrates an expanded view of FIG. 2( b ) showing the heat sink 210 and the LED emitter 202 . A heat sink 210 is shown to be affixed to the bottom of the LED emitter 202 which, since this embodiment is shown as a suspended or overhead light fixture, actually means that the heat sink 210 is around and above the LED emitter 202 . At least a portion of the heat sink 210 is external to the enclosure created by the optic element 206 . The heat sink may comprise a series of fins. The heat sink could alternatively, or additionally, include a mesh that extends from heat sink 210 and surrounds at least a portion of the outer surface of the optic element 206 between the LED emitter 202 and the concave surface of the optic element. The heat sink 210 may be manufactured of various heat dissipation materials known in the art, such as aluminum, copper, and carbon fiber. The heat sink may be painted in a color, for example painted in white, to enhance or alter the heat dissipation capability of the material. At least a portion of the heat sink 210 is external to the optic element 206 , but the heat sink 210 is coupled to the internal LED emitter 202 . This can be achieved, for example, at a break-through in the optic element at an end substantially opposite the concave surface of the optic element. This coupling effectively retains the LED emitter 202 substantially within the optic element 206 while also sealing the optic element 206 closed. Once assembled, the inside of the optic element 206 may be a solid, a vacuum, or may be filled with air or an inert gas. [0053] FIG. 3 is an illustration of a solid-state light source light fixture, in accordance with another embodiment of the present invention. Such a light fixture may be considered a pendant light fixture, as it is suspended by only one suspension mechanism. The pendant light fixture shown in FIG. 3 is also considered to be a revolved light fixture configuration, since the cross-sectional profile of the light fixture is substantially uniform as it is circumferentially rotated around its vertical axis. Of course, other embodiments may show variations in the cross-sectional profile as the light fixture is rotated around its vertical axis. In the embodiment shown in FIG. 3 , an LED array 312 is positioned to emit light radiation downwards towards a remote wavelength-conversion material 304 which is deposited on a conical-shaped transmissive optic element 306 . A conical-shaped reflector 308 is inversely affixed atop the LED array 312 and optic element 306 so as to provide an hour-glass appearance to the complete light fixture 300 . A heat sink 310 is adjacent or affixed to the LED array 312 between the reflector 308 and the optic element 306 . In this embodiment, the pendant-style light fixture 300 is suspended in the lighting location by a singular suspension mechanism 330 . The heat sink 310 may be used to mechanically support the radiation emitting light source, an LED array 312 in this embodiment, and utilized for heat dissipation purposes. [0054] FIGS. 4( a )- 4 ( f ) illustrate cross-sectional views of various light fixture configurations featuring one or more light sources, wave-length conversion materials, heat sinks, optic elements, and reflectors, in accordance with other embodiments of the present invention. As shown, the light source may be one light emitter positioned between the reflectors and the optic elements. FIG. 4( a ) shows an embodiment in which one light emitter is used to direct light towards a wavelength-conversion material deposited on, or integrated with, a triangular-shaped optic element. FIGS. 4( a ) and 4 ( f ) show embodiments of the present invention in which the wavelength-conversion material may be deposited on, or integrated with, one or more surfaces of the optic element. As discussed above and shown in FIGS. 4( a )- 4 ( f ), the optic element may take a number of other shapes. In each of the light fixture embodiments shown in FIGS. 4( a )- 4 ( f ), some light radiation emitted by the light source may be reflected back towards the light source as unconverted light radiation. The converted light may be forward transferred or back transferred. Additionally, some light may be transferred through the wavelength-conversion material without being converted (i.e., unconverted transmitted radiation). By capturing both the forward transferred portion and the back transferred portion of the down-converted light, system efficiency may be improved. Similarly, the position of the down-conversion material and the reflector, when one or more reflectors are utilized, may be adjusted to ensure that light from the light source impinges the down-conversion material uniformly to produce a uniform white light and allowing more of the light to exit the device. At the same time, positioning the down-conversion material remote from the light source prevents light feedback back into the light source. As a result, the heat at the light source is further minimized and results in improved light output and life. The shape of the optic element and the reflectors, as well as the position and number of light emitters, can be configured in any way to achieve increased light production, enhanced lighting efficiency, and improved energy utilization in comparison to known technologies. [0055] FIGS. 5( a )- 5 ( c ) illustrate cross-sectional views of various light fixture configurations featuring one or more light sources, wave-length conversion materials, heat sinks, optic elements, and reflectors, in accordance with other embodiments of the present invention. As shown, a number of light sources may be used. For example, FIGS. 5( a )- 5 ( d ) show embodiments having multiple light emitters 502 each. FIG. 5( a ) shows an embodiment in which two light emitters 502 are used to direct light towards a wavelength-conversion material deposited on, or integrated with, a pentagonal-shaped optic element. The light emitters 502 are affixed to heat sinks 510 . The light emitters 502 are positioned on one or more surfaces of the optic element 506 that are substantially opposite of the surface of the optic element on which the wavelength-conversion material 504 is deposited. In this configuration, the light emitters 502 are positioned between the wavelength-conversion material 504 and the reflectors 508 . The light emitters 502 emit light radiation towards the wavelength-conversion material 504 , where at least some light radiation is converted and back-transferred in the direction of the light emitters. The reflectors 508 are positioned to reflect at least a portion of the back-transferred converted light radiation to the desired environment, i.e., a lighted area. In the configuration shown in FIG. 5( a ), it is the back-transferred converted light radiation that is reflected by the reflectors and used, in addition to the forward transferred converted light radiation, to illuminate the desired area. [0056] The pentagonal-shaped optic element shown in FIG. 5( a ) is inverted in FIG. 5( b ). FIGS. 5( c ) and 5 ( d ) show further configurations of the light fixture in accordance with at least one embodiment of the present invention. The optic elements shown in FIGS. 5( c ) and 5 ( d ) may also be considered pentagonal-shaped optic elements, but with an internally depressed triangular profile instead of an externally pointed triangular profile. In each of the light fixture embodiments shown in FIGS. 5( a )- 5 ( d ), multiple light emitters 502 are used, which are each affixed with a heat sink 510 . FIG. 5( b ) shows an embodiment in which the wavelength-conversion material 504 is deposited on, or integrated with, one surface of the optic element 506 , while FIG. 5( c ) shows an embodiment in which the wavelength-conversion material 504 is deposited on, or integrated with, multiple surfaces of the optic element 506 . In the embodiment shown in FIG. 5( d ), the wavelength-conversion material 504 is deposited on a single surface of the optic element 506 that is perpendicular to the surfaces having the light emitters 502 . In the embodiments shown in FIGS. 5( a )- 5 ( d ), some light radiation emitted by the light emitters 502 may be reflected back towards the light source as unconverted light radiation. The converted light may be forward transferred or back transferred. Additionally, some light may be transferred through the wavelength-conversion material without being converted (i.e., unconverted transmitted radiation). In the embodiments shown in FIGS. 5( b ) and 5 ( c ), the wavelength-conversion material is deposited on one or more surfaces of the optic element which are between the light source and the reflectors. In such embodiments, the reflectors capture and reflect the forward transferred portion of the down-converted light radiation. The back-transferred portion of the down-converted light radiation is allowed to pass through the transmissive surfaces of the optic element. By capturing both the forward transferred portion and the back transferred portion of the down-converted light, system efficiency may be improved. As above, the shape of the optic element and the reflectors, as well as the position and number of light emitters, can be configured in any way to achieve increased light production, enhanced lighting efficiency, and improved energy utilization in comparison to known technologies. [0057] The light fixtures of the present invention may incorporate one or more reflectors having a myriad of shapes and sizes. FIGS. 6( a )- 6 ( c ) illustrate cross-sectional views of various light fixtures having reflectors of different shapes, in accordance with other embodiments of the present invention. Such reflectors may be used with both extruded-style light fixtures, as shown for example in FIG. 2( a ) and in FIGS. 6( a )- 6 ( c ), and with revolved-style light fixtures, as shown in FIG. 3 . In addition to extruded or revolved fixtures, the optic element of the SPE light fixtures of the present invention may have a number of sides. For example, the optic element may have a square, rectangular, trapezoidal, pentagonal, hexagonal, or octagonal shape, among other structural shapes. Optic elements having any of these structural shapes may be incorporated into any of the embodiments of the present invention. [0058] FIGS. 7( a ) and 7 ( b ) illustrate another exemplary embodiment of the invention using the SPE technique which feature an array of emitters 712 . FIGS. 7( a ) and 7 ( b ) illustrate the embodiments when used as a wall sconce and as a suspended pendant fixture, respectively. Here, the wall or ceiling to which the light fixture is mounted may behave as a reflector. FIG. 7( c ) shows the cross-sectional view for both embodiments. As shown, the SPE light fixture includes optic element 706 deposited with a layer of wavelength-converting material 704 . A reflector 708 having a high amount of transmissiveness (i.e., a low reflective coating), such as a translucent cover, may be used to control the output spectrum of the light fixture as well as provide desired aesthetics. FIG. 7( d ) illustrates an expanded view of FIG. 7( c ) showing the heat sink, optic elements, and the solid-state light emitting diode (LED). An LED or an LED array may be mounted on a heat sink. A mechanical part or suspension mechanism may be used to support the heat sink and affix the light fixture to the wall or ceiling. [0059] FIG. 8( a ) illustrates yet another exemplary embodiment of the invention using the SPE technique. It illustrates another high efficiency lighting fixture that uses solid-state light emitter(s) and a remote wavelength-converting material. FIG. 8( b ) is the sectional-view of the fixture in FIG. 8( a ). As shown, the fixture includes a wavelength-converting material 804 that is remote from light radiation emitter(s) 802 . Both the emitter(s) 802 and the wavelength-converting material 804 are affixed to, or integrated with, optic elements 806 . The wavelength-converting material 804 may be a phosphor. A reflector 808 may be used to control the output beam distribution and to improve the color uniformity the beam. Heat sink 810 may be used for mounting the emitter(s) 802 and for heat dissipation, as discussed above. A suspension mechanism 830 is used to suspend the wavelength-converting material 804 above the emitter(s) 802 within the enclosure created by the optic elements 806 . The suspension mechanism 830 may also be used to mount the SPE light fixture to the wall or ceiling. For a number of reasons, including improved beam control, light efficiency, and aesthetics, multiple reflectors may be used separately or together as compound reflective surfaces. FIG. 8( c ) illustrates a cross-sectional view of an embodiment incorporating a compound reflector 808 . Typical applications for the SPE light fixtures shown in FIGS. 8( a )- 8 ( c ) are recessed, pendant, and track down-light fixtures. [0060] FIGS. 9( a ) and 9 ( b ) illustrate a further embodiment of the present invention which includes a number of SPE light fixtures as a SPE light system or assembly. A SPE light system may be composed of a one or more SPE light fixtures, such as those shown in FIGS. 2-8 . The SPE light fixture within this SPE light system may be same or different. The individual SPE light fixtures may be connected via optic elements, reflectors, heat sinks, suspension mechanisms, or via other known components, as would be appreciated by one having ordinary skill in the art. [0061] The amount of heat from the LED light source and other necessary electronic elements going into the light fixture limits the total capacity of the LEDs that can be used with reliable performance and, therefore, limits the amount of light that is produced. Embodiments of the present invention place the LED source and heat sink in a manner to dissipate more of the heat produced by the LEDs into the environment. This arrangement enables a greater amount of light to be produced while ensuring that the proper operating temperatures for the LEDs and electronic elements are maintained. This arrangement may be even more beneficial for applications where the SPE light fixture is used in open luminaires, when compared to benefits achieved in completely enclosed luminaires. [0062] As stated before, the radiant energy hitting the down conversion material will be converted to a higher wavelength radiation and when mixed it will provide white light similar to the light produced by traditional light fixtures. The spectrum of the final light output depends on the wavelength-conversion material. The total light extraction depends on the amount of light reaching the wavelength-conversion layer, the thickness of the wavelength-conversion layer, and the materials and design of the optic elements and reflectors. These components can be shaped and sized in any manned contemplated to achieve the performance and aesthetic goals of the SPE light fixture. The Example and Table below detail efficiency and light radiation improvements enabled by the SPE light fixtures of the present invention. Example [0063] In at least one embodiment of the present invention, an LED package with SPE technique is implemented. Unlike a typical conventional white LED package, where the down conversion phosphor is spread around the light source or die, in the SPE package of the invention the phosphor layer is moved away from the die, leaving a transparent medium between the die and the phosphor. An efficient geometrical shape for such packages may be determined via ray tracing analysis. It is worth noting that the SPE package requires a different phosphor density to create white light with chromaticity coordinates similar to the conventional white LED package. This difference is a result of the SPE package mixing transmitted and back-reflected light with dissimilar spectra, whereas the conventional package uses predominantly the transmitted light. [0064] Computer simulations were conducted to determine the light output improvement using a SPE light fixture according to the embodiments of the present invention. A light fixture model shown in FIG. 10( a ) was setup in a ray-tracing software. The light fixture model shown in FIG. 10( a ) is similar to that shown in FIG. 2( a ), without one or more reflectors. For clarity, the configuration of the analyzed light fixture will be detailed with reference to FIG. 2( a ). The blue LED array 212 was enclosed by a clear optic element 206 . A phosphor wavelength-converting material 204 was attached or deposited onto the concave surface at the bottom of the optic element 206 . The phosphor density was selected to achieve 6500 kelvin correlated color temperature (CCT) on the black-body locus of the 1931 CIE diagram. [0065] FIG. 16 illustrates a few traced rays of the model. Another light fixture was modeled by changing the blue LEDs to same number of white LEDs. The phosphor layer was changed to a diffuser with the same dimensions. The white LEDs consist of the blue LED dies and phosphor spread around the blue LED dies. The radiant energies and emitting beam angles are the same from the blue LED dies in the white LEDs and from the blue LEDs used in the SPE light fixture. The CCT values and the chromaticity coordinates are the same in the white LEDs and in the SPE light fixture. Table 1 below shows the results of this comparative analysis: [0000] TABLE 1 Results of comparative analysis. Luminous flux CCT CIE (x, y) (lm) SPE fixture 6300K (0.316, 0.333) 541.3 White-LED fixture 6293K (0.315, 0.334) 416.2 [0066] As shown in Table 1 above, the simulations demonstrated that the SPE light fixture has about 30% more light than the fixture using white LEDs when the CCT and the chromaticity coordinates are the same in both configurations. [0067] Accordingly the present invention relates to a highly efficient SPE-based lighting fixture that includes solid-state radiation emitters (e.g., LEDs), a wavelength-converting material (e.g., a phosphor), and a reflector. The wavelength-converting material is placed away from the LEDs. The back transferred photons from the wavelength-converting material can be extracted to increase the overall efficiency of the fixture. Therefore, the fixture requires fewer LEDs or less electrical energy, and can cost less to manufacture. [0068] It will be understood that the geometry of the SPE light fixtures of the present invention is not limited to the specific shapes shown in the Figures, described above, or presented in the Examples. Alternate shapes may be used to achieve specific performance or aesthetics, while addressing other design concerns, such as light color and light source life. Although the invention has been described with reference to exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed to include other variants and embodiments of the invention which may be made by those skilled in the art without departing from the true spirit and scope of the present invention.

A light fixture includes a light source, a wavelength-conversion material, and a reflector. The light source is configured to emit a first radiation, and has a front surface and a back surface. The wavelength-conversion material is arranged under the front surface and configured to convert the first radiation to a second radiation which has a first portion not able to reach the reflector and a second portion able to reach the reflector. The reflector is arranged over the back surface and configured to reflect the second portion away from the light source without passing through the wavelength-conversion material. The reflector has an end distant from the light source and is arranged in an elevation different from that of the wavelength-conversion material.

BACKGROUND OF THE INVENTION This invention relates generally to electric motors and more particularly to an electric motor having a simplified, easily assembled construction. Assembly of electric motors requires that a rotor be mounted for rotation relative to a stator so that magnets on the rotor are generally aligned with one or more windings on the stator. Conventionally, this is done by mounting a shaft of the rotor on a frame which is attached to the stator. The shaft is received through the stator so that it rotates about the axis of the stator. The frame or a separate shell may be provided to enclose the stator and rotor. In addition to these basic motor components, control components are also assembled. An electrically commutated motor may have a printed circuit board mounting various components. Assembly of the motor requires electrical connection of the circuit board components to the winding and also providing for electrical connection to an exterior power source. The circuit board itself is secured in place, typically by an attachment to the stator with fasteners, or by welding, soldering or bonding. Many of these steps are carried out manually and have significant associated material labor costs. The fasteners, and any other materials used solely for connection, are all additional parts having their own associated costs and time needed for assembly. Tolerances of the component parts of the electric motor must be controlled so that in all of the assembled motors, the rotor is free to rotate relative to the stator without contacting the stator. A small air gap between the stator and the magnets on the rotor is preferred for promoting the transfer of magnetic flux between the rotor and stator, while permitting the rotor to rotate. The tolerances in the dimensions of several components may have an effect on the size of the air gap. The tolerances of these components are additive so that the size of the air gap may have to be larger than desirable to assure that the rotor will remain free to rotate in all of the motors assembled. The number of components which affect the size of the air gap can vary, depending upon the configuration of the motor. Motors are commonly programmed to operate in certain ways desired by the end user of the motor. For instance certain operational parameters may be programmed into the printed circuit board components, such as speed of the motor, delay prior to start of the motor, and other parameters. Mass produced motors are most commonly programmed in the same way prior to final assembly and are not capable of re-programming following assembly. However, the end users of the motor sometimes have different requirements for operation of the motor. In addition, the end user may change the desired operational parameters of the motor. For this reason, large inventories of motors, or at least programmable circuit boards, are kept to satisfy the myriad of applications. Electric motors have myriad applications, including those which require the motor to work in the presence of water. Water is detrimental to the operation and life of the motor, and it is vital to keep the stator and control circuitry free of accumulations of water. It is well known to make the stator and other components water proof. However, for mass produced motors it is imperative that the cost of preventing water from entering and accumulating in the motor be kept to a minimum. An additional concern when the motor is used in the area of refrigeration is the formation of ice on the motor. Not uncommonly the motor will be disconnected from its power source, or damaged by the formation of ice on electrical connectors plugged into the circuit board. Ice which forms between the printed circuit board at the plug-in connector can push the connector away from the printed circuit board, causing disconnection, or breakage of the board or the connector. SUMMARY OF THE INVENTION Among the several objects and features of the present invention may be noted the provision of an electric motor which has few component parts; the provision of such a motor which does not have fasteners to secure its component parts; the provision of such a motor which can be accurately assembled in mass production; the provision of such a motor having components capable of taking up tolerances to minimize the effect of additive tolerances; the provision of such a motor which can be re-programmed following final assembly; the provision of such a motor which inhibits the intrusion of water into the motor; and the provision of such a motor which resists damage and malfunction in lower temperature operations. Further among the several objects and features of the present invention may be noted the provision of a method of assembling an electric motor which requires few steps and minimal labor; the provision of such a method which minimizes the number of connections which must be made; the provision of such a method which minimizes the effect of additive tolerances; the provision of such a method which permits programming and testing following final assembly; and the provision of such a method which is easy to use. In one form, the invention comprises an electric motor. A stator includes a stator core having a winding thereon. A rotor includes a shaft received in the stator core for rotation of the rotor relative to the stator about the longitudinal axis of the shaft. A housing connected together with the stator and rotor forms an assembled motor, the housing being adapted to support the stator and rotor. A printed circuit board having programmable components thereon controls operation of the motor, the printed circuit board having contacts mounted thereon for use in programming the programmable components, the printed circuit board being received in the housing. The housing has a port therein generally in registration with the contacts on the printed circuit board, the port being sized and shaped to receive a probe connected to a microprocessor into connection to the contacts inside the housing for programming the motor. In another form, the invention comprises a method of assembling an electric motor comprising the steps of: forming a stator including a stator core and a winding thereon; forming a rotor including a rotor shaft; forming a housing adapted to support and at least partially enclose the stator and rotor; connecting a printed circuit board having a programmable component thereon to the winding; assembling the stator, rotor and housing such that the printed circuit board is enclosed in the housing; inserting a probe through a port in the housing into connection with contacts on the printed circuit board subsequent to said step of assembling the stator, rotor and housing; and programming the programmable component through the probe connection to the printed circuit board. Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded elevational view of an electric motor in the form of a fan; FIG. 2 is an exploded perspective view of component parts of a stator of the motor; FIG. 3 is a vertical cross sectional view of the assembled motor; FIG. 4 is the stator and a printed circuit board exploded from its installed position on the stator; FIG. 5 is an enlarged, fragmentary view of the shroud of FIG. 1 as seen from the right side; FIG. 6 is a side elevational view of a central locator member and rotor shaft bearing; FIG. 7 is a right end elevational view thereof; FIG. 8 is a longitudinal section of the locator member and bearing; FIG. 9 is an end view of a stator core of the stator with the central locator member and pole pieces positioned by the locator member shown in phantom; FIG. 10 is an opposite end view of the stator core; FIG. 11 is a section taken in the plane including line 11 — 11 of FIG. 10; FIG. 12 is a greatly enlarged, fragmentary view of the motor at the junction of a rotor hub with the stator; FIG. 13 is a section taken in the plane including line 13 — 13 of FIG. 5, showing the printed circuit board in phantom and illustrating connection of a probe to a printed circuit board in the shroud and a stop; FIG. 14 is a section taken in the plane including line 14 — 14 of FIG. 5 showing the printed circuit board in phantom and illustrating a power connector plug exploded from a plug receptacle of the shroud; and FIG. 15 is an enlarged, fragmentary view of the motor illustrating snap connection of the stator/rotor subassembly with the shroud. FIG. 16 is a block diagram of the microprocessor controlled single phase motor according to the invention. FIG. 17 is a schematic diagram of the power supply of the motor of FIG. 16 according to the invention. Alternatively, the power supply circuit could be modified for a DC input or for a non-doubling AC input. FIG. 18 is a schematic diagram of the low voltage reset for the microprocessor of the motor of FIG. 16 according to the invention. FIG. 19 is a schematic diagram of the strobe for the Hall sensor of the motor of FIG. 16 according to the invention. FIG. 20 is a schematic diagram of the microprocessor of the motor of FIG. 16 according to the invention. FIG. 21 is a schematic diagram of the Hall sensor of the motor of FIG. 16 according to the invention. FIG. 22 is a schematic diagram of the H-bridge array of witches for commutating the stator of the motor of FIG. 16 according to the invention. FIG. 23 is a flow diagram illustrating the operation of the microprocessor of the motor of the invention in a mode in which the motor is commutated at a constant air flow rate at a speed and torque which are defined by tables which exclude resonant points. FIG. 24 is a flow diagram illustrating operation of the microprocessor of the motor of the invention in a run mode (after start) in which the safe operating area of the motor is maintained without current sensing by having a minimum off time for each power switch, the minimum off time depending on the speed of the rotor. FIG. 25 is a timing diagram illustrating the start up mode which provides a safe operating area (SOA) control based on speed. FIG. 26 is a flow chart of one preferred embodiment of implementation of the timing diagram of FIG. 25 illustrating the start up mode which provides a safe operating area (SOA) control based on speed. FIG. 27 is a timing diagram illustrating the run up mode which provides a safe operating area (SOA) control based on speed. FIG 28 is a flow diagram illustrating the operation of the microprocessor of the motor of the invention in a run mode started after a preset number of commutations in the start up mode wherein in the run mode the microprocessor commutates the switches for N commutations at a constant commutation period and wherein the commutation period is adjusted every M commutations as a function of the speed, the torque or the constant air flow rate of the rotor. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and in particular to FIGS. 1 and 3, an electric motor 20 constructed according to the principles of the present invention includes a stator 22 , a rotor 24 and a housing 26 (the reference numerals designating their subjects generally). In the illustrated embodiment, the motor 10 is of the type which the rotor magnet is on the outside of the stator, and is shown in the form of a fan. Accordingly, the rotor 24 includes a hub 28 having fan blades 30 formed integrally therewith and projecting radially from the hub. The hub 28 and fan blades 30 are formed as one piece of a polymeric material. The hub is open at one end and defines a cavity in which a rotor shaft 32 is mounted on the axis of the hub (FIG. 3 ). The shaft 32 is attached to the hub 28 by an insert 34 which is molded into the hub, along with the end of the shaft when the hub and fan blades 30 are formed. A rotor magnet 35 exploded from the rotor in FIG. 1 includes a magnetic material and iron backing. For simplicity, the rotor magnet 35 is shown as a unitary material in the drawings. The back iron is also molded into the hub cavity at the time the hub is formed. The stator, 22 which will be described in further detail below, is substantially encapsulated in a thermoplastic material. The encapsulating material also forms legs 36 projecting axially of the stator 22 . The legs 36 each have a catch 38 formed at the distal end of the leg. A printed circuit board generally indicated at 40 , is received between the legs 36 in the assembled motor 10 , and includes components 42 , at least one of which is programmable, mounted on the board. A finger 44 projecting from the board 40 mounts a Hall device 46 which is received inside the encapsulation when the circuit board is disposed between the legs 36 of the stator 22 . In the assembled motor 10 , the Hall device 46 is in close proximity to the rotor magnet 35 for use in detecting rotor position to control the operation of the motor. The stator 22 also includes a central locator member generally indicated at 48 , and a bearing 50 around which the locator member is molded. The bearing 50 receives the rotor shaft 32 through the stator 22 for mounting the rotor 24 on the stator to form a subassembly. The rotor 24 is held on the stator 22 by an E clip 52 attached to the free end of the rotor after it is inserted through the stator. The housing 26 includes a cup 54 joined by three spokes 56 to an annular rim 58 . The spokes 56 and annular rim 58 generally define a shroud around the fan blades 30 when the motor 10 is assembled. The cup 54 , spokes 56 and annular rim 58 are formed as one piece from a polymeric material in the illustrated embodiment. The cup 54 is substantially closed on the left end (as shown in FIGS. 1 and 3 ), but open on the right end so that the cup can receive a portion of the stator/rotor subassembly. The annular rim 58 has openings 60 for receiving fasteners through the rim to mount the motor in a desired location, such as in a refrigerated case (not shown). The interior of the cup 54 is formed with guide channels 62 (FIG. 5) which receive respective legs 36 . A shoulder 64 is formed in each guide channel 62 near the closed end of the cup 54 which engages the catch 38 on a leg to connect the leg to the cup (see FIGS. 3 and 16 ). The diameter of the cup 54 narrows from the open toward the closed end of the cup so that the legs 36 are resiliently deflected radially inwardly from their relaxed positions in the assembled motor 10 to hold the catches 38 on the shoulders 64 . Small openings 66 in the closed end of the cup 54 (FIG. 5) permit a tool (not shown) to be inserted into the cup to pry the legs 36 off of the shoulders 64 for releasing the connection of the stator/rotor subassembly from the cup. Thus, it is possible to nondestructively disassemble the motor 10 for repair or reconfiguration (e.g., such as by replacing the printed circuit board 40 ). The motor may be reassembled by simply reinserting the legs 36 into the cup 54 until they snap into connection. One application for which the motor 10 of the illustrated in the particular embodiment is particularly adapted, is as an evaporator fan in a refrigerated case. In this environment, the motor will be exposed to water. For instance, the case may be cleaned out by spraying water into the case. Water tends to be sprayed onto the motor 10 from above and to the right of the motor in the orientation shown in FIG. 3, and potentially may enter the motor wherever there is an opening or joint in the construction of the motor. The encapsulation of the stator 22 provides protection, but it is desirable to limit the amount of water which enters the motor. One possible site for entry of what is at the junction of the hub 28 of the rotor and the stator 22 . An enlarged fragmentary view of this junction is shown in FIG. 12 . The thermoplastic material encapsulating the stator is formed at this junction to create a tortuous path 68 . Moreover, a skirt 70 is formed which extends radially outwardly from the stator. An outer edge 72 of the skirt 70 is beveled so that water directed from the right is deflected away from the junction. The openings 66 which permit the connection of the stator/rotor subassembly to be released are potentially susceptible to entry of water into the cup where it may interfere with the operation of the circuit board. The printed circuit board 40 , including the components 42 , is encapsulated to protect it from moisture. However, it is still undesirable for substantial water to enter the cup. Accordingly, the openings 66 are configured to inhibit entry of water. Referring now to FIG. 15, a greatly enlarged view of one of the openings 66 shows a radially outer edge 66 a and a radially inner edge 66 b . These edges lie in a plane P 1 which has an angle to a plane P 2 generally parallel to the longitudinal axis of the rotor shaft of at least about 45°. It is believed that water is sprayed onto the motor at an angle of no greater than 45°. Thus, it may be seen that the water has no direct path to enter the opening 66 when it travels in a path making an angle of 45° or less will either strike the side of the cup 54 , or pass over the opening, but will not enter the opening. The cup 54 of the housing 26 is also constructed to inhibit motor failures which can be caused by the formation of ice within the cup when the motor 10 is used in a refrigerated environment. More particularly, the printed circuit board 40 has power contacts 74 mounted on and projecting outwardly from the circuit board (FIG. 4 ). These contacts are aligned with an inner end of a plug receptacle 76 which is formed in the cup 54 . Referring to FIG. 14, the receptacle 76 receives a plug 78 connected to an electrical power source remote from the motor. External controls (not shown) are also connected to the printed circuit board 40 through the plug 78 . The receptacle 76 and the plug 78 have corresponding, rectangular cross sections so that when the plug is inserted, it substantially closes the plug receptacle. When the plug 78 is fully inserted into the plug receptacle 76 , the power contacts 74 on the printed circuit board 40 are received in the plug, but only partially. The plug receptacle 76 is formed with tabs 80 (near its inner end) which engage the plug 78 and limit the depth of insertion of the plug into the receptacle. As a result, the plug 78 is spaced from the printed circuit board 40 even when it is fully inserted in the plug receptacle 76 . In the preferred embodiment, the spacing is about 0.2 inches. However, it is believed that a spacing of about 0.05 inches would work satisfactorily. Notwithstanding the partial reception of the power contacts 74 in the plug 78 , electrical connection is made. The exposed portions of the power contacts 74 , which are made of metal, tend to be subject to the formation of ice when the motor 10 is used in certain refrigeration environments. However, because the plug 78 and circuit board 40 are spaced, the formation of ice does not build pressure between the plug and the circuit board which would push the plug further away from the circuit board, causing electrical disconnection. Ice may and will still form on the exposed power contacts 74 , but this will not cause disconnection, or damage to the printed circuit board 40 or the plug 78 . As shown in FIG. 13, the printed circuit board 40 also has a separate set of contacts 82 used for programming the motor 10 . These contacts 82 are aligned with a tubular port 84 formed in the cup 54 which is normally closed by a stop 86 removably received in the port. When the stop 86 is removed the port can receive a probe 88 into connection with the contacts 82 on the circuit board 40 . The probe 88 is connected to a microprocessor or the like (not shown) for programming or, importantly, re-programming the operation of the motor after it is fully assembled. For instance, the speed of the motor can be changed, or the delay prior to starting can be changed. Another example in the context of refrigeration is that the motor can be re-programmed to operate on different input, such as when demand defrost is employed. The presence of the port 84 and removable stop 86 allow the motor to be re-programmed long after final assembly of the motor and installation of the motor in a given application. The port 84 is keyed so that the probe can be inserted in only one way into the port. As shown in FIG. 5, the key is manifested as a trough 90 on one side of the port 84 . The probe has a corresponding ridge which is received in the trough when the probe is oriented in the proper way relative to the trough. In this way, it is not possible to incorrectly connect the probe 88 to the programming contacts. If the probe 88 is not properly oriented, it will not be received in the port 84 . As shown in FIG. 2, the stator includes a stator core (or bobbin), generally indicated at 92 , made of a polymeric material and a winding 94 wound around the core. The winding leads are terminated at a terminal pocket 96 formed as one piece with the stator core 92 by terminal pins 98 received in the terminal pocket. The terminal pins 98 are attached in a suitable manner, such as by soldering to the printed circuit board 40 . However, it is to be understood that other ways of making the electrical connection can be used without departing from the scope of the present invention. It is envisioned that a plug-in type connection (not shown) could be used so that no soldering would be necessary. The ferromagnetic material for conducting the magnetic flux in the stator 22 is provided by eight distinct pole pieces, generally indicated at 100 . Each pole piece has a generally U-shape and including a radially inner leg 100 a , a radially outer leg 100 b and a connecting cross piece 100 c . The pole pieces 100 are each preferably formed by stamping relatively thin U-shaped laminations from a web of steel and stacking the laminations together to form the pole piece 100 . The laminations are secured together in a suitable manner, such as by welding or mechanical interlock. One form of lamination (having a long radially outer leg) forms the middle portion of the pole piece 100 and another form of lamination forms the side portions. It will be noted that one pole piece (designated 100 ′ in FIG. 2) does not have one side portion. This is done intentionally to leave a space for insertion of the Hall device 46 , as described hereinafter. The pole pieces 100 are mounted on respective ends of the stator core 22 so that the radially inner leg 100 a of each pole piece is received in a central opening 102 of the stator core and the radially outer leg 100 b extends axially along the outside of the stator core across a portion of the winding. The middle portion of the radially outwardly facing side of the radially outer leg 100 b , which is nearest to the rotor magnet 35 in the assembled motor, is formed with a notch 100 d . Magnetically, the notch 100 d facilitates positive location of the rotor magnet 35 relative to the pole pieces 100 when the motor is stopped. The pole pieces could also be molded from magnetic material without departing from the scope of the present invention. In certain, low power applications, there could be a single pole piece stamped from metal (not shown), but having multiple (e.g., four) legs defining the pole piece bent down to extend axially across the winding. The pole pieces 100 are held and positioned by the stator core 92 and a central locator member, generally indicated at 104 . The radially inner legs 100 a of the pole pieces are positioned between the central locator member 104 and the inner diameter of the stator core 92 in the central opening 102 of the stator core. Middle portions of the inner legs 100 a are formed from the same laminations which make up the middle portions of the outer legs 100 b , and are wider than the side portions of the inner legs. The radially inner edge of the middle portion of each pole piece inner leg 100 a is received in a respective seat 104 a formed in the locator member 104 to accept the middle portion of the pole piece. The seats 104 a are arranged to position the pole pieces 100 asymmetrically about the locator member 104 . No plane passing through the longitudinal axis of the locator member 104 and intersecting the seat 104 a perpendicularly bisects the seat, or the pole piece 100 located by the seat. As a result, the gap between the radially outer legs 100 b and the permanent magnet 35 of the rotor 24 is asymmetric to facilitate starting the motor. The radially outer edge of the inner leg 100 a engages ribs 106 on the inner diameter of the stator core central opening 102 . The configuration of the ribs 106 is best seen in FIGS. 9-11. A pair of ribs ( 106 a , 106 b , etc.) is provided for each pole piece 100 . The differing angulation of the ribs 106 apparent from FIGS. 9 and 10 reflects the angular offset of the pole pieces 100 . The pole pieces and central locator member 104 have been shown in phantom in FIG. 9 to illustrate how each pair is associated with a particular pole piece on one end of the stator core. One of the ribs 106 d ′ is particularly constructed for location of the unbalanced pole piece 100 ′, and is engageable with the side of the inner leg 100 a ′ rather than its radially outer edge. Another of the ribs 106 d associated with the unbalanced pole piece has a lesser radial thickness because it engages the radially outer edge of the wider middle portion of the inner leg 100 a′. The central locator member 104 establishes the radial position of each pole piece 100 . As discussed more fully below, some of the initial radial thickness of the ribs 106 may be sheared off by the inner leg 100 a upon assembly to accommodate tolerances in the stator core 92 , pole piece 100 and central locator member 104 . The radially inner edge of each outer leg 100 b is positioned in a notch 108 formed on the periphery of the stator core 92 . Referring now to FIGS. 6-8, the central locator member 104 has opposite end sections which have substantially the same shape, but are angularly offset by 45° about the longitudinal axis of the central locator member (see particularly FIG. 7 ). The offset provides the corresponding offset for each of the four pole pieces 100 on each end of the stator core 92 to fit onto the stator core without interfering with one of the pole pieces on the opposite end. It is apparent that the angular offset is determined by the number of pole pieces 100 (i.e., 360° divided by the number of pole pieces), and would be different if a different number of pole pieces were employed. The shape of the central locator member 104 would be corresponding changed to accommodate a different number of pole pieces 100 . As shown in FIG. 8, the central locator member 104 is molded around a metal rotor shaft bearing 110 which is self lubricating for the life of the motor 10 . The stator core 92 , winding 94 , pole pieces 100 , central locator member 104 and bearing 110 are all encapsulated in a thermoplastic material to form the stator 22 . The ends of the rotor shaft bearing 110 are not covered with the encapsulating material so that the rotor shaft 32 may be received through the bearing to mount the rotor 24 on the stator 22 (see FIG. 3 ). Method of Assembly Having described the construction of the electric motor 10 , a preferred method of assembly will now be described. Initially, the component parts of the motor will be made. The precise order of construction of these parts is not critical, and it will be understood that some or all of the parts may be made a remote location, and shipped to the final assembly site. The rotor 24 is formed by placing the magnet 35 and the rotor shaft 32 , having the insert 34 at one end, in a mold. The hub 28 and fan blades 30 are molded around the magnet 35 and rotor shaft 32 so that they are held securely on the hub. The housing 26 is also formed by molding the cup 54 , spokes 56 and annular rim 58 as one piece. The cup 54 is formed internally with ribs 112 (FIG. 5) which are used for securing the printed circuit board 40 , as will be described. The printed circuit board 40 is formed in a conventional manner by connection of the components 42 to the board. In the preferred embodiment, the programming contacts 82 and the power contacts 74 are shot into the circuit board 40 , rather than being mounted by soldering (FIG. 4 ). The Hall device 46 is mounted on the finger 44 extending from the board and electrically connected to components 42 on the board. The stator 22 includes several component parts which are formed prior to a stator assembly. The central locator member 104 is formed by molding around the bearing 110 , which is made of bronze. The ends of the bearing 110 protrude from the locator member 104 . The bearing 110 is then impregnated with lubricant sufficient to last the lifetime of the motor 10 . The stator core 92 (or bobbin) is molded and wound with magnet wire and terminated to form the winding 94 on the stator core. The pole pieces 100 are formed by stamping multiple, thin, generally U-shaped laminations from a web of steel. The laminations are preferably made in two different forms, as described above. The laminations are stacked together and welded to form each U-shaped pole piece 100 , the laminations having the longer outer leg and wider inner leg forming middle portions of the pole pieces. However, one pole piece 100 ′ is formed without one side portion so that a space will be left for the Hall device 46 . The component parts of the stator 22 are assembled in a press fixture (not shown). The four pole pieces 100 which will be mounted on one end of the stator core 92 are first placed in the fixture in positions set by the fixture which are 90° apart about what will become the axis of rotation of the rotor shaft 32 . The pole pieces 100 are positioned so that they open upwardly. The central locator member 104 and bearing 110 are placed in the fixture in a required orientation and extend through the central opening 102 of the stator core 92 . The radially inner edges of the middle portions of the inner legs 100 a of the pole pieces are received in respective seats 104 a formed on one end of the central locator member 104 . The wound stator core 92 is set into the fixture generally on top of the pole pieces previously placed in the fixture. The other four pole pieces 100 are placed in the fixture above the stator core 92 , but in the same angular position they will assume relative to the stator core when assembly is complete. The pole pieces 100 above the stator core 92 open downwardly and are positioned at locations which are 45° offset from the positions of the pole pieces at the bottom of the fixture. The press fixture is closed and activated to push the pole pieces 100 onto the stator core 92 . The radially inner edges of the inner legs 100 a of the pole pieces 100 engage their respective seats 104 a of the central locator member. The seat 104 a sets the radial position of the pole piece 100 it engages. The inner legs 100 a of the pole pieces 100 enter the central opening 102 of the stator core 92 and engage the ribs 106 on the stator core projecting into the central opening. The variances in radial dimensions from design specifications in the central locator member 104 , pole pieces 100 and stator core 92 caused by manufacturing tolerances are accommodated by the inner legs 100 a shearing off some of the material of the ribs 106 engaged by the pole piece. The shearing action occurs as the pole pieces 100 are being passed onto the stator core 92 . Thus, the tolerances of the stator core 92 are completely removed from the radial positioning of the pole pieces. The radial location of the pole pieces 100 must be closely controlled so as to keep the air gap between the pole pieces and the rotor magnet 35 as small as possible without mechanical interference of the stator 22 and rotor 24 . The assembled stator core 92 , pole pieces 100 , central locator member 104 and bearing 110 are placed in a mold and substantially encapsulated in a suitable fire resistant thermoplastic. In some applications, the mold material may not have to be fire resistant. The ends of the bearing 110 are covered in the molding process and remain free of the encapsulating material. The terminal pins 98 for making electrical connection with the winding 94 are also not completely covered by the encapsulating material (see FIG. 4 ). The skirt 70 and legs 36 are formed out of the same material which encapsulates the remainder of the stator. The legs 36 are preferably relatively long, constituting approximately one third of the length of the finished, encapsulated stator. Their length permits the legs 36 to be made thicker for a more robust construction, while permitting the necessary resilient bending needed for snap connection to the housing 26 . In addition to the legs 36 and skirt 70 , two positioning tangs 114 are formed which project axially in the same direction as the legs and require the stator 22 to be in a particular angular orientation relative to the housing 26 when the connection is made. Still further, printed circuit board supports are formed. Two of these take the form of blocks 116 , from one of which project the terminal pins 98 , and two others are posts 118 (only one of which is shown). The encapsulated stator 22 is then assembled with the rotor 24 to form the stator/rotor subassembly. A thrust washer 120 (FIG. 3) is put on the rotor shaft 32 and slid down to the fixed end of the rotor shaft in the hub 28 . The thrust washer 120 has a rubber-type material on one side capable of absorbing vibrations, and a low friction material on the other side to facilitate a sliding engagement with the stator 22 . The low friction material side of the washer 120 faces axially outwardly toward the open end of the hub 28 . The stator 22 is then dropped into the hub 28 , with the rotor shaft 32 being received through the bearing 110 at the center of the stator. One end of the bearing 110 engages the low friction side of the thrust washer 120 so that the hub 28 can rotate freely with respect to the bearing. Another thrust washer 122 is placed on the free end of the bearing 110 and the E clip 52 is shaped onto the end of the rotor shaft 32 so that the shaft cannot pass back through the bearing. Thus, the rotor 24 is securely mounted on the stator 22 . The printed circuit board 40 is secured to the stator/rotor subassembly. The assembly of the printed circuit board 40 is illustrated in FIG. 4, except that the rotor 24 has been removed for clarity of illustration. The printed circuit board 40 is pushed between the three legs 36 of the stator 22 . The finger 44 of the circuit board 40 is received in an opening 124 formed in the encapsulation so that the Hall device 46 on the end of the finger is positioned within the encapsulation next to the unbalanced pole piece 100 ′, which was made without one side portion so that space would be provided for the Hall device. The side of the circuit board 40 nearest the stator 22 engages the blocks 116 and posts 118 which hold the circuit board at a predetermined spaced position from the stator. The terminal pins 98 projecting from the stator 22 are received through two openings 126 in the circuit board 40 . The terminal pins 98 are electrically connected to the components 42 circuit board in a suitable manner, such as by soldering. The connection of the terminal pins 98 to the board 40 is the only fixed connection of the printed circuit board to the stator 22 . The stator/rotor subassembly and the printed circuit board 40 are then connected to the housing 26 to complete the assembly of the motor. The legs 36 are aligned with respective channels 62 in the cup 54 and the tangs 114 are aligned with recesses 128 formed in the cup (see FIGS. 5 and 14 ). The legs 36 will be received in the cup 54 in only one orientation because of the presence of the tangs 114 . The stator/rotor subassembly is pushed into the cup 54 . The free ends of the legs 36 are beveled on their outer ends to facilitate entry of the legs into the cup 54 . The cup tapers slightly toward its closed end and the legs 36 are deflected radially inwardly from their relaxed configurations when they enter the cup and as they are pushed further into it. When the catch 38 at the end of each leg clears the shoulder 64 at the inner end of the channel 62 , the leg 36 snaps radially outwardly so that the catch engages the shoulder. The leg 36 is still deflected from its relaxed position so that it is biased radially outwardly to hold the catch 38 on the shoulder 64 . The engagement of the catch 38 with the shoulder 64 prevents the stator/rotor subassembly, and printed circuit board 40 from being withdrawn from the cup 54 . The motor 10 is now fully assembled, without the use of any fasteners, by snap together construction. The printed circuit board 40 is secured in place by an interference fit with the ribs 112 in the cup 54 . As the stator/rotor assembly advances into the cup 54 , peripheral edges of the circuit board 40 engage the ribs 112 . The ribs are harder than the printed circuit board material so that the printed circuit board is partially deformed by the ribs 112 to create the interference fit. In this way the printed circuit board 40 is secured in place without the use of any fasteners. The angular orientation of the printed circuit board 40 is set by its connection to the terminal pins 98 from the stator 22 . The programming contacts 82 are thus aligned with the port 84 and the power contacts 74 are aligned with the plug receptacle 76 in the cup 54 . It is also envisioned that the printed circuit board 40 may be secured to the stator 22 without any interference fit with the cup 54 . For instance, a post (not shown) formed on the stator 22 may extend through the circuit board and receive a push nut thereon against the circuit board to fix the circuit board on the stator. In the preferred embodiment, the motor 10 has not been programmed or tested prior to the final assembly of the motor. Following assembly, a ganged connector (not shown, but essentially a probe 88 and a power plug 78 ) is connected to the printed circuit board 44 through the port and plug receptacle 76 . The motor is then programmed, such as by setting the speed and the start delay, and tested. If the circuit board 40 is found to be defective, it is possible to non-destructively disassemble the motor and replace the circuit board without discarding other parts of the motor. This can be done by inserting a tool (not shown) into the openings 66 in the closed end of the cup 54 and prying the catches 38 off the shoulders 64 . If the motor passes the quality assurance tests, the stop 86 is placed in the port 84 and the motor is prepared for shipping. It is possible with the motor of the present invention, to re-program the motor 10 after it has been shipped from the motor assembly site. The end user, such as a refrigerated case manufacturer, can remove the stop 86 from the port 84 and connect the probe 88 to the programming contacts 82 through the port. The motor can be re-programmed as needed to accommodate changes made by the end user in operating specifications for the motor. The motor 10 can be installed, such as in a refrigerated case, by inserting fasteners (not shown) through the openings 60 in the annular rim 58 and into the case. Thus, the housing 26 is capable of supporting the entire motor through connection of the annular rim 58 to a support structure. The motor is connected to a power source by plugging the plug 78 into the plug receptacle 76 (FIG. 14 ). Detents 130 (only one is shown) on the sides of the plug 78 are received in slots on respective sides of a tongue 132 to lock the plug in the plug receptacle 76 . Prior to engaging the printed circuit board 40 , the plug 78 engages the locating tabs 80 in the plug receptacle 76 so that in its fully inserted position, the plug is spaced from the printed circuit board. As a result, the power contacts 74 are inserted far enough into the plug 78 to make electrical connection, but are not fully received in the plug. Therefore, although ice can form on the power contacts 74 in the refrigerated case environment, it will not build up between the plug 78 and the circuit board 40 causing disconnection and/or damage. FIG. 16 is a block diagram of the microprocessor controlled single phase motor 500 according to the invention. The motor 500 is powered by an AC power source 501 . The motor 500 includes a stator 502 having a single phase winding. The direct current power from the source 501 is supplied to a power switching circuit via a power supply circuit 503 . The power switching circuit may be any circuit for commutating the stator 502 such as an H-bridge 504 having power switches for selectively connecting the dc power source 501 to the single phase winding of the stator 502 . A permanent magnet rotor 506 is in magnetic coupling relation to the stator and is rotated by the commutation of the winding and the magnetic field created thereby. Preferably, the motor is an inside-out motor in which the stator is interior to the rotor and the exterior rotor rotates about the interior stator. However, it is also contemplated that the rotor may be located within and internal to an external stator. A position sensor such as a hall sensor 508 is positioned on the stator 502 for detecting the position of the rotor 506 relative to the winding and for providing a position signal via line 510 indicating the detected position of the rotor 506 . Reference character 512 generally refers to a control circuit including a microprocessor 514 responsive to and receiving the position signal via line 510 . The microprocessor 514 is connected to the H-bridge 504 for selectively commutating the power switches thereof to commutate the single phase winding of the stator 502 as a function of the position signal. Voltage VDD to the microprocessor 514 is provided via line 516 from the power supply circuit 503 . A low voltage reset circuit 518 monitors the voltage VDD on line 516 and applied to the microprocessor 514 . The reset circuit 518 selectively resets the microprocessor 514 when the voltage VDD applied to the microprocessor via line 516 transitions from below a predetermined threshold to above the predetermined threshold. The threshold is generally the minimum voltage required by the microprocessor 514 to operate. Therefore, the purpose of the reset circuit 518 is to maintain operation and re-establish operation of the microprocessor in the event that the voltage VDD supplied via line 516 drops below the preset minimum required by the microprocessor 514 to operate. Optionally, to save power, the hall sensor 508 may be intermittently powered by a hall strobe 520 controlled by the microprocessor 514 to pulse width modulate the power applied to the hall sensor. The microprocessor 514 has a control input 522 for receiving a signal which affects the control of the motor 500 . For example, the signal may be a speed select signal in the event that the microprocessor is programmed to operate the rotor such that the stator is commutated at two or more discrete speeds. Alternatively, the motor may be controlled at continuously varying speeds or torques according to temperature. For example, in place of or in addition to the hall sensor 508 , an optional temperature sensor 524 may be provided to sense the temperature of the ambient air about the motor. This embodiment is particularly useful when the rotor 506 drives a fan which moves air through a condenser for removing condenser generated heat or which moves air through an evaporator for cooling, such as illustrated in FIGS. 1-15. In one embodiment, the processor interval clock corresponds to a temperature of the air moving about the motor and for providing a temperature signal indicating the detected temperature. For condenser applications where the fan is blowing air into the condenser, the temperature represents the ambient temperature and the speed (air flow) is adjusted to provide the minimum needed air flow at the measured temperature to optimize the heat transfer process. When the fan is pulling air over the condenser, the temperature represents ambient temperature plus the change in temperature (Δt) added by the heat removed from the condenser by the air stream. In this case, the motor speed is increased in response to the higher combined temperature (speed is increased by increasing motor torque, i.e., reducing the power device off time PDOFFTIM; see FIG. 26 ). Additionally, the speed the motor could be set for different temperature bands to give different air flow which would be distinct constant air flows in a given fan static pressure condition. Likewise, in a condenser application, the torque required to run the motor at the desired speed represents the static load on the motor. The higher static loads can be caused by installation in a restricted environment, i.e., a refrigerator installed as a built-in, or because the condenser air flow becomes restricted due to dust build up or debris. Both of these conditions may warrant an increased air flow/speed. Similarly, in evaporator applications, the increased static pressure could indicate evaporator icing or increased packing density for the items being cooled. In one of the commercial refrigeration applications, the evaporator fan pulls the air from the air curtain and from the exit air cooling the food. This exhaust of the fan is blown through the evaporator. The inlet air temperature represents air curtains and food exit air temperature. The fan speed would be adjusted appropriately to maintain the desired temperature. Alternatively, the microprocessor 514 may commutate the switches at a variable speed rate to maintain a substantially constant air flow rate of the air being moved by the fan connected to the rotor 506 . In this case, the microprocessor 514 provides an alarm signal by activating alarm 528 when the motor speed is greater than a desired speed corresponding to the constant air flow rate at which the motor is operating. As with the desired torque, the desired speed may be determined by the microprocessor as a function of an initial static load of the motor and changes in static load over time. FIG. 23 illustrates one preferred embodiment of the invention in which the microprocessor 514 is programmed according to the flow diagram therein. In particular, the flow diagram of FIG. 23 illustrates a mode in which the motor is commutated at a constant air flow rate corresponding to a speed and torque which are defined by tables which exclude resonant points. For example, when the rotor is driving a fan for moving air over a condenser, the motor will have certain speeds at which a resonance will occur causing increased vibration and/or increased audio noise. Speeds at which such vibration and/or noise occur are usually the same or similar and are predictable, particularly when the motor and its associated fan are manufactured to fairly close tolerances. Therefore, the vibration and noise can be minimized by programming the microprocessor to avoid operating at certain speeds or within certain ranges of speeds in which the vibration or noise occurs. As illustrated in FIG. 23, the microprocessor 514 would operate in the following manner. After starting, the microprocessor sets the target variable I to correspond to an initial starting speed pointer defining a constant air flow rate at step 550 . For example, I=0. Next, the microprocessor proceeds to step 552 and selects a speed set point (SSP) from a table which correlates each of the variable levels 0 to n to a corresponding speed set point (SSP), to a corresponding power device off time (PDOFFTIM=P min ) for minimum power and to a corresponding power device off time (PDOFFTIM=P max ) for maximum power. It is noted that as the PDOFFTIM increases, the motor power decreases since the controlled power switches are off for longer periods during each commutation interval. Therefore, the flow chart of FIG. 23 is specific to this approach. Others skilled in the art will recognize other equivalent techniques for controlling motor power. After a delay at step 554 to allow the motor to stabilize, the microprocessor 514 selects a PDOFFTIM for a minimum power level (P min ) from the table which provides current control by correlating a minimum power level to the selected level of variable I. At step 558 the microprocessor selects a PDOFFTIM for a maximum power level (P max ) from the table which provides current control by correlating a maximum power level to the selected variable level I. At step 560 , the microprocessor compares the actual PDOFFTIM representing the actual power level to the minimum PDOFFTIM (P min ) for this I. If the actual PDOFFTIM is greater than the minimum PDOFFTIM (PDOFFTIM>P min ), the microprocessor proceeds to step 562 and compares the variable level I to a maximum value n. If I is greater or equal to n, the microprocessor proceeds to step 564 to set I equal to n. Otherwise, I must be less than the maximum value for I so the microprocessor 514 proceeds to step 566 to increase I by one step. If, at step 560 , the microprocessor 514 determines that the actual PDOFFTIM is less than or equal to the minimum PDOFFTIM (PDOFFTIM≦P min ), the microprocessor proceeds to step 568 and compares the actual PDOFFTIM representing the actual power level to the maximum PDOFFTIM (P max ) for this I. If the actual PDOFFTIM is less than the maximum PDOFFTIM (PDOFFTIM<P max ), the microprocessor proceeds to step 570 and compares the variable level I to a minimum value 0. If I is less or equal to 0, the microprocessor proceeds to step 572 to set I equal to 0. Otherwise, I must be greater than the minimum value for I so the microprocessor 514 proceeds to step 574 to decrease I by one step. If the actual PDOFFTIM is less than or equal to the minimum and is greater than or equal to the maximum so that the answer to both steps 560 and 568 is no, the motor is operating at the speed and power needed to provide the desired air flow so the microprocessor returns to step 552 to maintain its operation. Alternatively, the microprocessor 514 may be programmed with an algorithm which defines the variable rate at which the switches are commutated. This variable rate may vary continuously between a preset range of at least a minimum speed S min and not more than a maximum speed S max except that a predefined range of speeds S 1 +/−S 2 is excluded from the preset range. As a result, for speeds between S 1 −S 2 and S 1 , the microprocessor operates the motor at S 1 −S 2 and for speeds between S 1 and S 1 +S 2 , the microprocessor operates the motor at speeds S 1 +S 2 . FIG. 22 is a schematic diagram of the H-bridge 504 which constitutes the power switching circuit having power switches according to the invention, although other configurations may be used, such as two windings which are single ended or the H-bridge configuration of U.S. Pat. No. 5,859,519, incorporated by reference herein. The dc input voltage is provided via a rail 600 to input switches Q 1 and Q 2 . An output switch Q 3 completes one circuit by selectively connecting switch Q 2 and stator 502 to a ground rail 602 . An output switch Q 4 completes another circuit by selectively connecting switch Q 1 and stator 502 to the ground rail 602 . Output switch Q 3 is controlled by a switch Q 5 which receives a control signal via port BQ 5 . Output switch Q 4 is controlled by a switch Q 8 which receives a control signal via port BQ 8 . When switch Q 3 is closed, line 604 pulls the gate of Q 1 down to open switch Q 1 so that switch Q 1 is always open when switch Q 3 is closed. Similarly, line 606 insures that switch Q 2 is open when switch Q 4 is closed. The single phase winding of the stator 502 has a first terminal F and a second terminal S. As a result, switch Q 1 constitutes a first input switch connected between terminal S and the power supply provided via rail 600 . Switch Q 3 constitutes a first output switch connected between terminal S and the ground rail 602 . Switch Q 2 constitutes a second input switch connected between the terminal F and the power supply provided via rail 600 . Switch Q 4 constitutes a second output switch connected between terminal F and ground rail 602 . As a result, the microprocessor controls the first input switch Q 1 and the second input switch Q 2 and the first output switch Q 3 and the second output switch Q 4 such that the current through the motion is provided during the first 90° of the commutation period illustrated in FIG. 27 . The first 90° is significant because of noise and efficiency reasons and applies to this power device topology (i.e., either Q 1 or Q 2 is always “on” when either Q 3 or Q 4 is off, respectively. PDOFFTIM is the term used in the software power control algorithms. When the first output switch Q 3 is open, the first input switch Q 1 is closed. Similarly, the second input switch Q 2 is connected to and responsive to the second output switch Q 4 so that when the second output switch Q 4 is closed, the second input switch Q 2 is open. Also, when the second output switch Q 4 is open, the second input switch Q 2 is closed. This is illustrated in FIG. 27 wherein it is shown that the status of Q 1 is opposite the status of Q 3 and the status of Q 2 is opposite the status of Q 4 at any instant in time. FIG. 26 is a timing flow chart illustrating the start up mode with a current maximum determined by the setting of PDOFFTIM versus the motor speed. In this mode, the power devices are pulse width modulated by software in a continuous mode to get the motor started. The present start algorithm stays in the start mode eight commutations and then goes into the RUN mode. A similar algorithm could approximate constant acceleration by selecting the correct settings for PDOFFTIM versus speed. At step 650 , the value HALLIN is a constant defining the starting value of the Hall device reading. When the actual Hall device reading (HALLOLD) changes at step 652 , HALLIN is set to equal HALLOLD at step 654 and the PDOFFTIM is changed at step 656 depending on the RPMs. FIG. 25 illustrates the microprocessor outputs (BQ 5 and BQ 8 ) that control the motor when the strobed hall effect output (HS 3 ) changes state. In this example, BQ 5 is being pulse width modulated while HS 3 is 0. When HS 3 (strobed) changes to a 1, there is a finite period of time (LATENCY) for the microprocessor to recognize the magnetic change after which BQ 5 is in the off state so that BQ 8 begins to pulse width modulate (during PWMTIM). FIG. 24 illustrates another alternative aspect of the invention wherein the microprocessor operates within a run mode safe operating area without the need for current sensing. In particular, according to FIG. 24, microprocessor 514 controls the input switches Q 1 -Q 4 such that each input switch is open or off for a minimum period of time (PDOFFTIM) during each pulse width modulation period whereby over temperature protection is provided without current sensing. Specifically, the minimum period may be a function of the speed of the rotor whereby over temperature protection is provided-without current sensing by limiting the total current over time. As illustrated in FIG. 24, if the speed is greater than a minimum value (i.e., if A<165), A is set to 165 and SOA limiting is bypassed and not required; if the speed is less than (or equal to) a minimum value (i.e., if A≧165), the routine of FIG. 24 ensures that the switches are off for a minimum period of time to limit current. “A” is a variable and is calculated by an equation that represents a PDOFFTIM minimum value at a given speed (speed is a constant multiplied by 1/TINPS, where TINPS is the motor period). Then, if PDOFFTIM is<A, PDOFFTIM is set to A so that the motor current is kept to a maximum desired value at the speed the motor is running. As illustrated in FIG. 18, the motor includes a reset circuit 512 for selectively resetting the microprocessor when a voltage of the power supply vdd transitions from below a predetermined threshold to above a predetermined threshold. In particular, switch Q 6 disables the microprocessor via port MCLR/VPP when the divided voltage between resistors R 16 and R 17 falls below a predetermined threshold. The microprocessor is reactivated and reset when the voltage returns to be above the predetermined threshold thereby causing switch Q 6 to close. FIG. 19 illustrates one preferred embodiment of a strobe circuit 520 for the hall sensor 508 . The microprocessor generates a pulse width modulated signal GP 5 which intermittently powers the hall sensor 508 as shown in FIG. 21 by intermittently closing switch Q 7 and providing voltage VB 2 to the hall sensor 508 via line HS 1 . FIG. 17 is a schematic diagram of the power supply circuit 503 which supplies the voltage V in for energizing the stator single phase winding via the H-bridge 504 and which also supplies various other voltages for controlling the H-bridge 504 and for driving the microprocessor 514 . In particular, the lower driving voltages including VB 2 for providing control voltages to the switches Q 1 -Q 4 , VDD for driving the microprocessor, HS 2 for driving the hall sensor 508 , and VSS which is the control circuit reference ground not necessarily referenced to the input AC or DC voltage are supplied from the input voltage V in via a lossless inline series capacitor C 1 . FIG. 20 illustrates the inputs and outputs of microprocessor 514 . In particular, only a single input GP 4 from the position sensor is used to provide information which controls the status of control signal BQ 5 applied to switch Q 5 to control output switch Q 3 and input switch Q 1 and which controls the status of control signal EQS applied to switch Q 8 to control output switch Q 4 and input switch Q 2 . Input GP 2 is an optional input for selecting motor speed or other feature or may be connected for receiving a temperature input comparator output when used in combination with thermistor 524 . FIG. 28 illustrates a flow chart of one preferred embodiment of a run mode in which the power devices are current controlled. In this mode, the following operating parameters apply: MOTOR RUN POWER DEVICE (CURRENT) CONTROL At the end of each commutation, the time power devices will be off the next time the commutation period is calculated. OFFTIM=TINP/2. (The commutation period divided by 2=90°). While in the start routine, this is also calculated. After eight commutations (1 motor revolution) and at the start routine exit, PWMTIM is calculated: PWMTIM=OFFTIM/4 At the beginning of each commutation period, a counter (COUNT 8 ) is set to five to allow for four times the power devices will be turned on during this commutation: PWMSUM=PWMTIM PDOFFSUM=PWMTIM−PDOFFTIM TIMER=0 (PDOFFTIM is used to control the amount of current in the motor and is adjusted in the control algorithm (SPEED, TORQUE, CFM, etc.). Commutation time set to 0 at each strobed hall change, HALLOLD is the saved hall strobe value. During motor run, the flow chart of FIG. 28 is executed during each commutation period. In particular at step 702 , the commutation time is first checked to see if the motor has been in this motor position for too long a period of time, in this case 32 mS. If it has, a locked rotor is indicated and the program goes to the locked rotor routine at step 704 . Otherwise, the program checks to see if the commutation time is greater then OFFTIM at step 706 ; if it is, the commutation period is greater than 90 electrical degrees and the program branches to step 708 which turns the lower power devices off and exits the routine at step 710 . Next, the commutation time is compared at step 712 to PWMSUM. If it is less than PWMSUM, the commutation time is checked at step 714 to see if it is less or equal to PDOFFSUM where if true, the routine is exited at step 716 ; otherwise the routine branches to step 708 (if step 714 is yes). For the other case where the commutation time is greater or equal to PWMSUM, at step 718 PWMSUM and PDOFFSUM have PWMTIM added to them to prepare for the next pulse width modulation period and a variable A is set to COUNT 8 - 1 . If A is equal to zero at step 720 , the pulse width modulations (4 pulses) for this commutation period are complete and the program branches to step 708 to turn the lower power devices off and exit this routine. If A is not equal to zero, COUNT 8 (which is a variable defining the number of PWMs per commutation) is set to A at step 722 ; the appropriate lower power device is turned on; and this routine is exited at step 716 . More PWM counts per commutation period can be implemented with a faster processor. Four (4) PWMs per commutation period are preferred for slower processors whereas eight (8) are preferred for faster processors. The timing diagram for this is illustrated in FIG. 27 . In the locked rotor routine of step 704 , on entry, the lower power devices are turned off for 1.8 seconds after which a normal start attempt is tried. In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions without departing from the scope of the invention, 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.

An electric motor having a snap-together construction without the use of separate fasterners. The construction of the motor removes additive tolerances for a more accurate assembly. The motor is capable of programming and testing after final assembly and can be non-destructively disassembled for repair or modification. The motor is constructed to inhibit the ready entry of water into the motor housing and to limit the effect of any water which manages to enter the housing.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a Continuation of U.S. application Ser. No. 11/593,171 filed on Nov. 6, 2006. Priority is claimed based on U.S. application Ser. No. 11/593,171 filed on Nov. 6, 2006, which claims priority to Japanese Patent Application No. 2005-323401, filed on Nov. 8, 2005, all of which is incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a support system for inputting appropriate genotype data into an analysis system in gene analysis to identify genes associated with phenotypes of diseases, physical appearance features or the likes in individuals. [0004] 2. Background Art [0005] Genome mapping has been advanced for the human, animals and plants and analytical studies on gene functions are actively under progress. Of those studies, attract a particular attention studies through analysis of linkage disequilibrium which are to search the genome for genes associated with phenotypes (traits) of diseases, physical appearance features or the likes in individuals. As shown in FIG. 32 , a case will be now discussed where individuals A to Z of the same species are compared with respect to genome. Individuals of the same species have generally very similar nucleotide sequences, but different nucleotides in some positions. In FIG. 32 , the individuals have different nucleotides in loci 1 and 2 . Here, the term “locus” refers to a specific location in a genomic nucleotide sequence. [0006] Such a polymorphic occurrence of a single nucleotide in the genome among individuals is called SNP (single nucleotide polymorphism). A single locus is typically occupied by either of two different nucleotides (for example, A and T), but may be occupied by any one of three or more different nucleotides (for example, A, T and G) in very rare cases. In the case shown in FIG. 32 , more individuals have T in locus 1 , and therefore T is termed “major” in locus 1 , while A is termed “minor.” Similarly, G is termed “major” in locus 2 , while C is termed “minor.” [0007] A case where the same locus is occupied by A in an individual but by no nucleotide in another individual, or a similar case may also happen. In this case, if the first individual views the genome of the latter individual, it is observed to have deletion of a nucleotide A, but if the latter individual views the genome of the first individual, conversely, it is observed to have insertion of the nucleotide A. Such a polymorphic presence/absence of a single nucleotide in the same locus among individuals is called in/del (abbreviation of insertion/deletion) of the single nucleotide. [0008] On the other hand, individuals of many biological species have a pair of genomes (homologous chromosomes) derived from both a female gamete and a male gamete. Genes present at sites corresponding to one another in the pair of genomes are called alleles to one another, and a pair of these alleles is called a genotype. The two alleles may be the same or different since there are different nucleotide sequence portions among individuals in genome. When genes at a particular genomic site are paid attention to, the presence of the same two alleles is called homozygotes, while the presence of different two alleles is called heterozygotes. [0009] When chromosomes are transferred from a parent to a child, the single genome undergoes crossing-over by meiosis and thus gene recombination in the transfer. It is generally believed that two distant genes in the genome are likely to be recombined, but two near genes in the genome are difficult to be recombined. When genes located at two different loci in the genome tend to be transferred from a parent to a child as they are linked, the expression that the two loci have a linkage is used. [0010] Genetic search of hereditary diseases associated with a small number of genes has been conducted up to now by linkage analysis using a program such as “LINKAGE” where data of a large family including at least one patient are input. An Example of Linkage Analysis Programs: LINKAGE [0011] It was developed by Rockefeller University in USA. Genotype data of a large family including at least one patient are used for linkage analysis. ftp://linkage.rockefeller.edu/software/linkage/ [0013] On another front, in the search of genes which affect multifactorial diseases attracting current attention (diseases such as lifestyle-related diseases which afflict numerous patients and are probably associated with many genes as well as environmental factors), analysis of linkage disequilibrium is actively conducted for which a general population without blood relationship is used, as described below. [0014] In a single genome derived from either a female gamete or a male gamete, a set of alleles present at multiple linked loci is called a haplotype. Individuals having two homologous genomes in a pair have always two haplotypes in a pair. [0015] A phenomenon may be occasionally observed where the frequency of a certain haplotype for multiple linked loci is significantly different from a frequency which is given by product of frequencies for alleles at the respective loci (the alleles are distributed interdependently among the multiple linked loci). In this case, the expression that those loci are at linkage disequilibrium is used. [0016] The above analysis of linkage disequilibrium can be used to search the genomes of individuals for genes associated with phenotypes (traits) of diseases, physical appearance features or the likes. Two approaches to the analysis will be described below. The first approach will be now described. It is assumed that most of genes responsible to common diseases in a population are formed by mutation of common ancestor genes (common disease common variant assumption). According to the assumption, an SNP allele close to the locus where such mutation occurred would be inherited in a combination with the pathogenic gene. In other words, linkage disequilibrium would be observed between the locus for the pathogenic gene and SNP loci close thereto. Therefore, such a region in the genome is called a linkage disequilibrium block or a haplotype bloc. A haplotype block common to individuals suffering from a certain disease can be searched to identify a gene causing the disease. The second approach will be now described. If the SNP allele close to the mutated gene is inherited to the patient population together with the pathogenic gene, as described above according to the common disease common variant assumption, the frequency of the allele would be different between the patient population and the healthy population. This deduction draws the assumption that conversely, an SNP allele having a different frequency between the patient population and the healthy population would be accompanied by a pathogenic gene close thereto. An approach of combining multiple SNPs to form a haplotype is similarly used to compare its frequency between the patient population and the healthy population. [0017] When genes associated with phenotypes are searched for using linkage disequilibrium analysis, tens to hundreds of individual samples, sometimes at least a thousand of those, are typically used to examine genotypes at several to hundreds of loci, sometimes about ten thousand loci. In addition, many programs for linkage disequilibrium analysis using genotypes as input data have been developed and are now available as described below. Example 1 of Programs for Linkage Disequilibrium Analysis: ARLEQUIN [0018] It was developed by University of Geneva in Switzerland. Genotypic data of unrelated individuals are used to test the Hardy-Weinberg equilibrium and calculate for linkage disequilibrium. [0019] Stefan Schneider, David Roessli, and Laurent Excoffier (2000) Arlequin ver. 2000: A software for population genetics data analysis. Genetics and Biometry Laboratory, University of Geneva, Switzerland. Example 2 of Programs for Linkage Disequilibrium Analysis: Haploview [0020] It was developed by Whitehead Institute in USA. Genotypic data of unrelated individuals are used to verify the number of missing samples for each locus, verify the Hardy-Weinberg equilibrium (described later), verify distances among loci, verify the frequencies of minor alleles and calculate for haplotype blocs (see J. C. Barrett, B. Fry, J. Maller and M. J. Daly, “Haploview: analysis and visualization of LD and haplotype maps”, Bioinformatics vol. 21, no. 2 (2005), pages 263-265). Example 3 of Programs for Linkage Disequilibrium Analysis: Varia [0021] It was developed by Silicon Genetics Inc. in USA (as of filing the present patent application, the same software known as “GeneSpring GT” is available from Agilent Technologies Inc. in USA). Genotypic data of family or unrelated individuals are used to carry out data analyses such as calculation for haplotype blocs. http://www.silicongenetics.com/cgi/SiG.cgi/Products/Varia/features.smf [0023] IUB code, which is described in FIG. 33 , is one of description formats for input data (genotype data) which is used in a program to carry out linkage disequilibrium analysis. In the IUB coding system, names of loci are described one after another on the first line ( 3300 ), and the data of respective individuals are described on the second and following lines ( 3301 ). In the description of the respective individual data, the presence/absence of a disease is described at the leftmost place on the line ( 3302 ), an individual identifier is described next ( 3303 ), and then genotypes carried by the individual are described one after another according to the order of the loci described on the first line ( 3304 ). As for the presence/absence of a disease, patients are described as “Patient”, while healthy individuals are described as “Normal”. Genotypes are described by IUB codes shown in FIG. 34 . In the example shown in FIG. 33 , the individual p 001 is a patient, is a heterozygote comprised of A and T at locus 1 , and is a homozygote comprised of A at locus 2 . The term “missing” means no genotype data available due to experimental failure or the like. Of the genotypic descriptors shown in FIG. 34 , “−”, “a”, “t”, “g” and “c” are used in in/del polymorphism. [0024] In addition, algorithms taking account of distances between loci (by how many nucleotides are the two loci separated?) for calculations have been proposed to determine haplotype blocs. Therefore, location of each locus is necessary to be specified in its input data. FIG. 35 is one of formats for such location. In this format, the data of each locus is described on each line, where the name of each locus is described in the leftmost place of each line ( 3500 ) and its physical position (of what number is the nucleotide in order starting from the top of the chromosome?) is described next ( 3501 ). [0025] When a pathogenic gene is searched for with the help of a program, it is problematic that false descriptions are present in the input data. The program assumes that the input data given is perfectly correct. However, genotype data obtained experimentally are often processed into electronic data or changed in format in manually, and hence it is almost impossible to completely prevent false descriptions in the input data. In addition to errors made in manual input of the data, errors may be brought in from wrong experimental results. Taking them together, numerous errors may happen. [0026] For conventional linkage analyses, the approach of making sure if genotype data are consistent or not by use of parenthood is presented such as Varia or Checkfam. Example of Contradiction Detection Programs for Genotype Data in Linkage Analysis: Checkfam [0027] It was developed by Tokyo Women's Medical University. Genotypic data with information of families are used to search them for contradiction as to inheritance of alleles. http://www.genstat.net/checkfam/index.cgi?lang=ja [0029] As for input data for linkage disequilibrium analysis, however, no correction measures have ever been taken though various errors may occur as described below. [0000] Error 1: No Data of Physical Positions of Loci are Provided in the Input Data for a Program Requiring them [0030] In this case, input files are not so adequate as to execute the analysis program. [0000] Error 2: Loci are not Arranged in Order of their Physical Positions (in a Chromosome) in the Input Data for a Program where the Loci are Assumed Arranged Correctly [0031] In this case, the program may abnormally terminate on the way, or analysis results may be different from those intended even if the program can be executed. When the program has been apparently executed to the end, there is a risk that the researcher may not recognize that analysis results are different from those intended. [0000] Error 3: Some Loci are Present in the same Physical Position in the Input Data for a Program where Physical Positions of Loci are not Assumed Overlapped [0032] There is a risk that physical positions of loci may become inconsistent and overlapped depending on how they are re-counted when the genomic sequence data of the chromosome is updated, or how they are counted for in/del polymorphism. Error 4: No Genotype Data is Specified for a Particular Locus/the Physical Position is not Specified [0033] Some SNPs have multiple locus names due to the process of their discovery. In addition, in the description of locus names, “(ABI)” may be appended to the locus names of SNPs developed by Applied Biosystems Inc., and “(JSNP)” may be appended to the locus names of SNPs developed by the JSNP project. In this case, there is a risk that the additional character strings may drop off or turn into double-byte characters while the input data are produced manually. When inconsistent locus names are produced by these causes, a particular locus is processed by a program as if no genotype data therefor were specified/the physical position thereof were not specified. Such a situation is time-consuming to find out a cause for the problem and solve it. [0000] Error 5: Unexpected Character Strings are used to Represent Genotypes [0034] In the IUB codes shown in FIG. 34 , “0” is intended to denote missing data. However, a symbol such as “*” (asterisk) or the like may be used by mistake to denote missing data. Or, “AT”, the continuous form of the two alleles, rather than “W” may be used by mistake again to denote a heterozygote comprised of A and T. In this situation, the program may abnormally terminate on the way due to appearance of the unexpected character string. [0000] Error 6: Individuals Belonging to an Unexpected Population are used/only one of the Populations is Provided in the Input Data for a Program where a Patient Population and a Healthy Population are Intended for Analysis [0035] In the format shown in FIG. 33 , it is intended that a patient is described as “Patient” and a healthy person as “Normal”. By mistake, however, the patient may be described as “Case”, or the healthy person may be described as “Control”. In addition, a capital letter may be accidentally replaced by a lower-case letter. Furthermore, a something beginning with “P” should be specified as an identifier for the patient and a something beginning with “N” as an identifier for the healthy person, but in some cases, the presence/absence of a disease may be omitted. In these situations, the program may abnormally terminate on the way. [0000] Error 7: A Locus Comprising Three or more Alleles is Present [0036] Four causes can be presumed as follows. [0037] The first cause is that three or more alleles have been actually present at the locus, and thus it is not a false description. However, the feature of an experimental technique taken must be considered because the base sequence reading experiment or the use of a DNA microarray allows three or more alleles to be differentiated, but the TaqMan assay or the like may allow only two alleles to be differentiated. Some programs directed to SNP are based on the assumption that each locus has two alleles. In such programs, a relevant locus must be removed from the analysis, or the least frequent allele must be combined with the most frequent allele. [0038] The second cause is that a heterozygous genotype has been described by mistake. In 3600 in FIG. 36 , the individual P 03 has alleles G and C at the locus 2 . As shown in FIG. 34 , a heterozygote comprised of G and C should be described as “S”, but is now assumed to have been described as “K”. Since K denotes a heterozygote comprised of G and T, it would be considered to have three alleles (G, C and T) though it actually has the two alleles (G and C). [0039] The third cause is that missing data has been described as a blank character (a one-byte space, tab or the like) rather than “0”. In FIG. 36 , the individual P 02 has no genotype at the locus 2 . The missing data should be described as “0”, but is now assumed to have been described as a one-byte space, as shown in 3601 . Since a one-byte space means a break character in analysis programs for linkage disequilibrium, genotypic data at locus 2 and higher-numbered loci would shift one by one and be thus interpreted as the data shown in 3602 . The loci 2 and 3 would be considered to have three or more alleles, respectively, according to the results of interpretation by the analysis program for linkage disequilibrium (the genotypic data connected to each other by the grey dotted line in 3601 and 3602 ), though they have only two alleles, respectively, according to the actual data (the genotypic data connected to each other by the grey bold line in 3601 and 3602 ). The individual P 02 would have an unspecified genotype at the last locus 4 . [0040] The fourth cause is that a heterozygous genotype has been described by mistake. In FIG. 36 , the genotype at the locus 2 in the individual P 03 should be described as “S”, but is now assumed to have been described as “G C” where the two alleles are separated by a one-byte space. In this case, genotypic data at locus 3 and higher-numbered loci would shift in a direction opposite to that shown in 3601 and be thus interpreted as the data shown in 3604 . The loci 3 and 4 would be considered to have three or more alleles, respectively, according to the results of interpretation by the analysis program for linkage disequilibrium (the genotypic data connected to each other by the grey dotted line in 3603 and 3604 ), though they have only two alleles, respectively, according to the actual data (the genotypic data connected to each other by the grey bold line in 3603 and 3604 ). The individual P 03 would have a specified genotype at the last locus (the locus name is unspecified). [0041] In the cases of the third and fourth causes, it is not only difficult to associate the false description with the abnormal termination of the program, but also almost impossible to find out the false description among a large amount of the data including samples from 1,000 or more individuals and hundreds of loci. Such a situation is time-consuming to find out a cause for the problem and solve it. [0000] Error 8: Loci Lack of Polymorphism are Contained in the Input Data for a Program where every Locus is Assumed to Display Polymorphism [0042] When researchers use loci registered in a public data base such as JSNP, the loci are described as polymorphic in the data base, but may not be polymorphic (monomorphic) in the samples of the researchers. Some algorithms of linkage disequilibrium analysis are defined under the assumption that every locus used in the analysis displays polymorphism. For instance, a linkage disequilibrium measure, D′ is determined by calculation using the frequencies of alleles in a divisor. Accordingly, the measure is not defined for a locus having an allele with zero frequency. If non-polymorphic loci are contained in the input data for such a program, the program could abnormally terminate on the way, or analysis results could be different from those intended even if the program can be executed. [0000] Error 9: In/del Polymorphism is Contained in the Input Data for a Program where nothing other than A, T, G or C is Assumed to Appear in Alleles [0043] In this situation, the program could abnormally terminate on the way, or analysis results could be different from those intended even if the program can be executed. [0000] Error 10: An Extraordinarily Great Number of Individuals have the same Heterozygous Locus [0044] To study genotypes experimentally, a short nucleotide sequence called a probe is provided for each locus in many cases. In SNP samples provided by JSNP or Applied Biosystems Inc., it may be expected that the probe is confirmed to react with only one location on the genome, but in SNP samples registered in a public data base such as dbSNP, which can be accessed by the general public, or in SNP samples provided by researchers on their own, the probe may react with two locations, though it is rare, as shown in 3700 of FIG. 37 . If it happens, such experimental results is obtained as if nearly all individuals had a single locus 2 (a portion enclosed by a dotted line) displaying a heterozygote comprised of T and C, as shown in 3701 , though neither locus 2 - 1 nor locus 2 - 2 actually displays polymorphism. [0000] Error 11: An Extraordinarily Great Number of Individuals have the same Homozygous Locus [0045] There are two conceivable causes. The first cause is that a sample population comprises many samples containing such homozygote samples. For diseases which may be caused by homozygous mutation at a higher risk than by heterozygous mutation, a patient population may be homozygote more frequently. The second cause is that the sample population is composed of two populations. For instance, there is now assumed to be a locus 3 where every individual of human race 1 has C and every individual of human race 2 has G. If the sample population comprises the two human races, the resultant data seem as if the locus displayed polymorphism, as shown in FIG. 38 though either of the races is not polymorphic. A sample population composed of two or more populations is not suitable for the analysis. [0000] Error 12: Some Individuals have an Extraordinarily Great Number of Heterozygous Loci [0046] There may happen a case where one sample is accidentally contaminated by a portion of another sample during the experiment. In the state shown in 3900 of FIG. 39 , the DNA of the individual P 02 is now assumed to have been incorporated into the DNA of the individual P 01 . As for the individual P 01 , the resultant data is observed as if the loci 1 and 2 had A and T, and G and C, respectively, as shown in 3901 , though it is the fact that the loci 1 and 2 have only A and G, respectively, as allele. Therefore, the individual P 01 would have the experimental result that there are heterozygotes in many gene loci. [0000] Error 13: Some Individuals have an Extraordinarily Great Number of Homozygous Loci [0047] In a case shown in FIG. 40 , the individual P 03 is homozygous at every locus. Such an individual may be a special individual (for example, consanguineous marriages may have been made in the family line). In linkage disequilibrium analysis, it is postulated that samples have been chosen randomly from both a patient population and a healthy population. Consequently, it is often preferable to exclude this individual. [0000] Error 14: Some Individuals have many Missing Data [0048] As shown in FIG. 41 , many experimental failures may occasionally happen in a particular individual (P 01 in this case) and produce many missing data. If it happens, accuracy of haplotype estimation would fall and/or a wider confidence interval. Accordingly, it is preferable to make both an analysis including the data of the individual P 01 and an analysis excluding it. [0000] Error 15: Some Loci have many Missing Data [0049] As shown in FIG. 42 , many experimental failures may occasionally happen in a particular locus (locus 2 in this case) and produce many missing data. In addition, when genotype data from two or more research institutions are analyzed together, only one of the institutions is now assumed to have studied on locus 2 experimentally. If it happens, the data from the other institution will be treated as data having nothing but missing data for locus 2 . In these cases, it is preferable to make both an analysis including the data for the locus 2 and an analysis excluding it, as in Error 14. [0000] Error 16: The Sample Population Deviates from the Hardy-Weinberg Equilibrium [0050] When a population has a good number of individuals and has the conditions that: no individuals immigrate into a different population; random mating in population is made; and neither mutations nor natural selections occur, the population is said to be in Hardy-Weinberg equilibrium. If the sample population used in the analysis deviates from Hardy-Weinberg equilibrium, it will be doubtful if the samples have been taken randomly, and a suitable analysis could not be made. [0000] Error 17: Some of the Loci used in the Analysis are Extremely Distant from the other Loci [0051] When the distance between the loci is very long, it is highly unlikely to think that the loci are in linkage disequilibrium (the loci are inherited as a bunch from the ancestor). Therefore, these loci should not be analyzed at once for linkage disequilibrium. [0000] Error 18: Some Loci have Extremely Rare Alleles [0052] In a search for pathogenic genes by statistical gene analysis, it is usually considered desirable to analyze only loci having a minor allele with a frequency of at least 5%, preferably of at least 10 to 30%. This limitation is set to prevent the power of statistic test from lowering by use of loci having alleles with an extremely low frequency. Accordingly, it is preferable to make both an analysis including the data for the locus and an analysis excluding them. [0053] It is the object of the present invention to provide a data input support system which can preliminarily detect and remove such causes of errors as described above in making entries of genotype data for a program to execute linkage disequilibrium analysis or the like. SUMMARY OF THE INVENTION [0054] As a result of every effort to solve the problem described above, the present inventors have now proposed a data input support system wherein, paying attention to limiting conditions characteristic of genotype input data and the statistical properties of the entire data set, the types of possible errors are preliminarily assumed, the input data are preprocessed to detect these errors, and the detected errors are associated with false descriptions causing them in order to report the results to the user. By means of such a data input support system, linkage disequilibrium analysis using appropriate data can be conducted efficiently, and the output of analysis results contrary to the user's intention can be avoided. More specifically, the following functions 1 to 15 will be used as means to correct the above errors 1 to 15, respectively. [0055] Function 1: the system retains information as to if each analysis program needs the physical positions of loci as input data, and if an analysis program specified by a user needs the specified physical positions of loci, but they have not yet been specified in the input data, the system reports it. [0056] Function 2-1: the system retains information as to if each analysis program assumes the arrangement of loci in order of their physical positions, and if an analysis program specified by a user assumes the arrangement of loci in order of their physical positions, but such arrangement is not provided in the input data, the system reports it. [0057] Function 2-2: if Function 2-1 applies, the system produces a modified version of the input data having the loci rearranged. [0058] Function 3: the system checks if the physical positions of loci overlap, and if they overlap, the system reports it. [0059] Function 4-1: the system checks if loci having genotypes unspecified in every individual and loci having physical positions unspecified are present. If such a set of loci is present, the system checks if the loci have similar names, and if the loci have similar names, the system reports possible false descriptions of the names of the loci. [0060] Function 4-2: if Function 4-1 applies, the system produces a modified version of the input data having the names of the loci made uniform into one of the names. [0061] Function 5-1: the system checks if a symbol such as “*” (asterisk) is specified as genotype data, and if genotypes have such a symbol, the system reports possible false descriptions of the missing data. [0062] Function 5-2: if Function 5-1 applies, the system produces a modified version of the input data having the descriptions of the genotypes replaced by “0” for missing data. [0063] Function 5-3: the system checks if continuous form of two alleles such as AT are specified as genotype data, and if genotypes have such character strings, the system reports possible false descriptions of the heterozygous genotypes. [0064] Function 5-4: if Function 5-3 applies, the system produces a modified version of the input data having the replaced descriptions of the heterozygous genotypes. [0065] Function 5-5: the system checks if unexpected character strings such as “N” are specified as genotype data, and if genotypes have such character strings, the system reports it. [0066] Function 6-1: the system retains information as to if each analysis program assumes the use of patients and healthy persons as input data, and if an analysis program specified by a user assumes the use of patients and healthy persons as input data, but the names of their populations are unspecified, the system reports it. [0067] Function 6-2: the system checks if “Case” or “Control” is specified as population name, or an erroneously spelled name for “Patient” or “Normal” is specified where capital and/or small letters are wrongly used, and reports such a possible false description of “Patient” or “Normal”. [0068] Function 6-3: if Function 6-2 applies, the system produces a modified version of the input data having the descriptions of the population names replaced by “Patient” or “Normal”. [0069] Function 6-4: the system retains information as to if each analysis program assumes the use of patients and healthy persons as input data, and if an analysis program specified by a user assumes the use of patients and healthy persons, but an unexpected character string such as “Japanese” is specified as population name, the system reports it. [0070] Function 7-1: the system retains information as to if each analysis program assumes the presence of two alleles at each locus and information as to what experimental technique is taken for each locus, and if an analysis program specified by a user assumes the presence of two alleles, or such an experimental technique is taken as can discriminate only two alleles, but loci with three or more alleles are actually present, the system reports it. [0071] Function 7-2: if Function 7-1 applies, the system produces a modified version of the input data where those loci are excluded from the input data to be analyzed. [0072] Function 7-3: if Function 7-1 applies, the system produces a modified version of the input data where the most frequent allele is combined with a third or higher-numbered most frequent allele in those loci. [0073] Function 7-4: the system checks if there are loci having three or more alleles. If such loci are present, the system checks if both conditions described below are satisfied. If both of the conditions are satisfied, the system reports possible false descriptions of genotypes where the most frequent two of the alleles are heterozygous. 1) The most frequent two of the alleles are developed only as homozygotes, and there are no individuals having heterozygotes between the most frequent two of the alleles. 2) A third or higher-numbered most frequent allele is developed only as heterozygotes, and there are no individuals having homozygotes between the third and higher-numbered most frequent alleles. [0074] Function 7-5: if Function 7-4 applies, the system produces a modified version of the input data having the heterozygous genotypes rewritten. [0075] Function 7-6: the system checks if there is a locus having three or more alleles. If such a locus is present, the system checks if all of the four conditions described below are satisfied. If all of the four conditions are satisfied, the system reports possible descriptions of missing data as blank characters (a one-byte space, tab or the like). 1) A number of loci having three or more alleles appear which are more highly numbered than the above locus. 2) It is the same individual that has a third or higher-numbered most frequent allele at each locus having three or more alleles. 3) In the individual having a third or higher-numbered most frequent allele in common, the genotype at the last locus is not specified. 4) A third or higher-numbered most frequent allele at each locus having three or more alleles appears as a first or second most frequent allele at the next right locus. [0076] Function 7-7: if Function 7-6 applies, the system produces a modified version of the input data having the descriptions of missing data replaced by “0”. [0077] Function 7-8: the system checks if there is a locus having three or more alleles. If such a locus is present, the system checks if all of the four conditions described below are satisfied. If all of the four conditions are satisfied, the system reports possible description of a heterozygous genotype by two alleles separated by a one-byte space. 1) A number of loci having three or more alleles appear which are more highly numbered than the above locus. 2) It is the same individual that has a third or higher-numbered most frequent allele at each locus having three or more alleles. 3) In the individual having a third or higher-numbered most frequent allele in common, the last locus with no specified locus name has a specified genotype. 4) A third or higher-numbered most frequent allele at each locus having three or more alleles appears as a first or second most frequent allele at the next left locus. [0078] Function 7-9: if Function 7-8 applies, the system produces a modified version of the input data having the heterozygous genotype rewritten. [0079] Function 7-10: the system checks if blank characters (a one-byte space, tab or the like) are irregularly used. If any of the following three conditions is satisfied, the system reports possible interpretation of the input data contrary to the intention of a user. 1) Two or more kinds of blank characters are used as break character for the input data. 2) Two or more blank characters appear in succession. 3) Such characters (a double-byte space or the like) as may be interpreted as either blank character or data are used. [0080] In the IUB coding system, an individual identifier and locus data, or locus data to each other are assumed to be separated by a blank character (a one-byte space, tab or the like), typically a tab. However, since blank characters are not displayed on the screen by a usual text editor, two or more kinds of blank characters may be present one after another, or a double-byte space may be accidentally input in stead of a one-byte space, or an unnecessary blank character may be input at the end of a line. Furthermore, since a usual spreadsheet software interprets data by tab delimitation and displays each column of data in a vertical arrangement, a user may possibly not recognize that genotype data have been missed out, or described as a one-byte or double-byte space, or described as two alleles separated by a one-byte space. Error 7 described above can be securely prevented by utilizing Function 7-10 to report the irregular uses of blank characters. [0081] Function 8-1: the system retains information as to if each analysis program assumes every locus to be polymorphic, and if an analysis program specified by a user assumes polymorphism in such a way, but some loci are monomorphic, the system reports it. [0082] Function 8-2: if Function 8-1 applies, the system produces a modified version of the input data where the loci are excluded from the input data to be analyzed. [0083] Function 9-1: the system retains information as to if each analysis program assumes nothing but A, T, G and C as allele, and if an analysis program specified by a user assumes nothing but A, T, G and C as allele, but some loci are in/del polymorphic, the system reports it. [0084] Function 9-2: if Function 9-1 applies, the system produces a modified version of the input data where the in/del polymorphic loci are excluded. [0085] Function 10-1: the system checks if there are loci heterozygous in extremely many individuals, and if such loci are present, the system reports possible reaction of probes for the loci at two or more locations on the genome. [0086] Function 10-2: if Function 10-1 applies, the system produces a modified version of the input data where the loci are excluded from the input data to be analyzed. [0087] Function 11: the system checks if there are loci homozygous in extremely many individuals, and if such loci are present, the system reports a possible presence of two or more populations in the sample population. [0088] Function 12-1: the system checks if there are individuals having extremely many heterozygous loci, and if such individuals are present, the system reports a possible contamination. [0089] Function 12-2: if Function 12-1 applies, the system produces a modified version of the input data where the individuals are excluded from the input data to be analyzed. [0090] Function 13-1: the system checks if there are individuals having extremely many homozygous loci, and if such individuals are present, the system reports a possible peculiarity of the individuals. [0091] Function 13-2: if Function 13-1 applies, the system produces a modified version of the input data where the individuals are excluded from the input data to be analyzed. [0092] Function 14-1: the system checks if there are individuals having many missing data, and if such individuals are present, the system reports it. [0093] Function 14-2: if Function 14-1 applies, the system produces a modified version of the input data where the individuals are excluded from the input data to be analyzed. [0094] Function 15: the system lists and displays both the items reported using Functions 1 to 14-2 described above and the items for which modified versions of the input data have been produced. [0095] Errors 1 to 14 can be prevented by use of Functions 1 to 14-2, respectively. In addition, Errors 15, 16, 17 and 18 can be dealt with by conventional techniques such as Haploview and Varia described above. [0096] The present invention provides, as a system having the above Functions 1 to 15, a data input support system to inspect genotype data which are input into a program for linkage disequilibrium analysis, wherein the system comprises a storage section for retaining error types for genotype data corresponding to the program for linkage disequilibrium analysis, an error detection section for checking the input genotype data for the error types and detecting errors, and an error report/display section for displaying the report of the detected errors. [0097] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data has no data on the physical positions of loci, opposed to a program for linkage disequilibrium analysis requiring genotype data on the physical positions of the loci. This provides the above Function 1. [0098] In the inventive data input support system, the error types are characterized by comprising the error that in the input genotype data, the loci are not arranged in order of their physical positions, opposed to a program for linkage disequilibrium analysis corresponding only to genotype data where the loci are arranged in order of their physical positions. This provides the above Function 2 (branch number is omitted, and it will be omitted hereafter). [0099] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data has the physical positions of loci overlapped. This provides the above Function 3. [0100] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains loci having genotypes unspecified and loci having physical positions unspecified. This provides the above Function 4. [0101] In the inventive data input support system, the error types are characterized by comprising the error that in the input genotype data, some symbols denoting a homozygote, a heterozygote or missing data are different from those defined by the program for linkage disequilibrium analysis. This provides the above Function 5. [0102] In the inventive data input support system, the error types are characterized by comprising the error that in the input genotype data, neither a patient population nor a healthy population is specified according to the definitions made by a program for linkage disequilibrium analysis, opposed to the program for linkage disequilibrium analysis requiring the genotype data of both patients and healthy persons. This provides the above Function 6. [0103] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains loci having three or more alleles, opposed to a program for linkage disequilibrium analysis defining that at most two alleles are present in a locus. This provides the above Function 7. [0104] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains any of the following descriptions: 1) at least two different blank characters are used as break character for the input data; 2) at least two blank characters appear in succession; and 3) characters are used which can be interpreted as either blank character or genotype data depending on the type of a program for linkage disequilibrium analysis. [0108] This provides the above Function 7. [0109] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains monomorphic loci, opposed to a program for linkage disequilibrium analysis defining that every locus is polymorphic. This provides the above Function 8. [0110] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains in/del polymorphic loci, opposed to a program for linkage disequilibrium analysis defining that nothing but A, T, G or C appears as allele. This provides the above Function 9. [0111] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains a higher level of individuals where the locus is heterozygous than a predetermined level, or a higher level of individuals where the locus is homozygous than a predetermined level. Herein, the predetermined level may be selected from a rate of number of individuals, a P value in a statistical test, or the like. This provides the above Functions 10 and 11. [0112] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains individuals having a higher level of heterozygous loci than a predetermined level, or individuals having a higher level of homozygous loci than a predetermined level. Herein, the predetermined level may be selected from a rate of number of individuals, a P value in a statistical test, or the like. This provides the above Functions 12 and 13. [0113] In the inventive data input support system, the error types are characterized by comprising the error that the input genotype data contains individuals having a higher level of missing data than a predetermined level. Herein, the predetermined level used may be a rate of number of individuals or the like. This provides the above Function 14. [0114] In the inventive data input support system, the above Function 7 has further characteristics as described below. [0115] If genotype data contain loci having three or more alleles, and both conditions described below are satisfied, the error report/display section displays a report on possible false descriptions in the input genotype data of genotypes where the most frequent two of the three or more alleles are heterozygous. 1) In the input genotype data, there are no individuals having heterozygote comprised of the most frequent two of the three or more alleles. 2) In the input genotype data, there are no individuals having homozygosis between the third and higher-numbered most frequent ones of the three or more alleles. [0118] If genotype data contain a locus having three or more alleles, and the four conditions described below are satisfied, the error report/display section displays a report on possible false descriptions in the input genotype data of missing data. 1) In the input genotype data, a certain or more number of loci having three or more alleles is present subsequent to the locus having three or more alleles. 2) In the input genotype data, the same individual has a third or higher-numbered most frequent allele of the three or more alleles at two or more loci. 3) In the input genotype data, in the individual applying to the above 2), the genotype at the last locus is not specified. 4) In the input genotype data, a third or higher-numbered most frequent allele at a locus having three or more alleles appears as a first or second most frequent allele at the next right locus. [0123] If genotype data contain a locus having three or more alleles, and the four conditions described below are satisfied, the error report/display section displays a report on possible false description in the input genotype data of a heterozygous genotype. 1) In the input genotype data, a certain or more number of loci having three or more alleles is present subsequent to the locus having three or more alleles. 2) In the input genotype data, the same individual has a third or higher-numbered most frequent allele of the three or more alleles at two or more loci. 3) In the input genotype data, in the individual applying to the above 2), the genotype at the last locus is specified. 4) In the input genotype data, a third or higher-numbered most frequent allele at a locus having three or more alleles appears as a first or second most frequent allele at the next left locus. [0128] In addition, the inventive data input support system is characterized by also comprising error correction means to accept an input for correcting the reported error in the input genotype data and correct the input genotype data based on the input. [0129] In the inventive data input support system, the error correction means is characterized by accepting a correction input by which for the locus having three or more alleles, a third or higher-numbered most frequent allele of the three or more alleles is rewritten into a first or higher-numbered most frequent allele, and thereby correcting the genotype data in such a manner. [0130] The inventive data input support system is characterized by further comprising means to display as a list the content of errors reported by the error report/display section as well as the content of corrections for the genotype data by the error correction means. [0131] According to the present invention, as described above, various errors can be detected which are contained in data to be input for a program for linkage disequilibrium analysis or the like, and the errors can be associated with false descriptions resulting in the errors to display the results. In this way, the linkage disequilibrium analysis can be conducted efficiently using appropriate data, and the output of analysis results contrary to the intention of a user can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS [0132] FIG. 1 is a functional block diagram outlining the system configuration of the inventive support system for interpretation of genetic data; [0133] FIG. 2 illustrates a data composition of program data stored in the data memory of the inventive support system for interpretation of genetic data; [0134] FIG. 3 illustrates a data composition of input data stored in the data memory of the inventive support system for interpretation of genetic data; [0135] FIG. 4 is a flow chart outlining processing in the inventive support system for interpretation of genetic data; [0136] FIG. 5 is a flow chart showing a detailed flow of the processing of detecting and reporting errors, accepting user input, and producing a modified version of the input data in the inventive support system for interpretation of genetic data; [0137] FIG. 6 is a flow chart showing a detailed flow of the processing of checking and reporting if an unexpected genotype is present in the inventive support system for interpretation of genetic data; [0138] FIG. 7 is a flow chart showing a detailed flow of the processing of checking and reporting if a population name is erroneous in the inventive support system for interpretation of genetic data; [0139] FIG. 8 is a flow chart showing a detailed flow of the processing of checking and reporting if a locus having three or more alleles is present in the inventive support system for interpretation of genetic data; [0140] FIG. 9 illustrates a display screen made by a physical position specification report processing section at step 500 in the flow chart shown in FIG. 5 ; [0141] FIG. 10 illustrates a display screen made by a physical position order report processing section at step 501 in the flow chart shown in FIG. 5 ; [0142] FIG. 11 illustrates a display screen made by a physical positions overlap report processing section at step 502 in the flow chart shown in FIG. 5 ; [0143] FIG. 12 illustrates a display screen made by a similar locus name report processing section at step 503 in the flow chart shown in FIG. 5 ; [0144] FIG. 13 illustrates a display screen made by a symbol genotype report processing section at step 600 in the flow chart shown in FIG. 6 ; [0145] FIG. 14 illustrates a display screen made by a character string genotype report processing section at step 601 in the flow chart shown in FIG. 6 ; [0146] FIG. 15 illustrates a display screen made by an unexpected genotype report processing section at step 602 in the flow chart shown in FIG. 6 ; [0147] FIG. 16 illustrates a display screen made by a specified population name report processing section at step 700 in the flow chart shown in FIG. 7 ; [0148] FIG. 17 illustrates a display screen made by a falsely described population name report processing section at step 701 in the flow chart shown in FIG. 7 ; [0149] FIG. 18 illustrates a display screen made by an unexpected population name report processing section at step 702 in the flow chart shown in FIG. 7 ; [0150] FIG. 19 illustrates a display screen made by a multiple alleles report processing section at step 803 in the flow chart shown in FIG. 8 ; [0151] FIG. 20 illustrates a display screen made by a falsely described heterozygotes report processing section at step 802 in the flow chart shown in FIG. 8 ; [0152] FIG. 21 illustrates a display screen made by a missing blank report processing section at step 800 in the flow chart shown in FIG. 8 ; [0153] FIG. 22 illustrates a display screen made by a heterozygosis blank report processing section at step 801 in the flow chart shown in FIG. 8 ; [0154] FIG. 23 illustrates a display screen made by an irregular blank character report processing section at step 804 in the flow chart shown in FIG. 8 ; [0155] FIG. 24 illustrates a display screen made by a monomorphism report processing section at step 507 in the flow chart shown in FIG. 5 ; [0156] FIG. 25 illustrates a display screen made by an in/del report processing section at step 508 in the flow chart shown in FIG. 5 ; [0157] FIG. 26 illustrates a display screen made by a dual site reaction report processing section at step 509 in the flow chart shown in FIG. 5 ; [0158] FIG. 27 illustrates a display screen made by a plural populations report processing section at step 510 in the flow chart shown in FIG. 5 ; [0159] FIG. 28 illustrates a display screen made by contamination report processing section at step 511 in the flow chart shown in FIG. 5 ; [0160] FIG. 29 illustrates a display screen made by a special individual report processing section at step 512 in the flow chart shown in FIG. 5 ; [0161] FIG. 30 illustrates a display screen made by a missing individual report processing section at step 513 in the flow chart shown in FIG. 5 ; [0162] FIG. 31 illustrates a display screen made by a reported/corrected items display processing section at step 514 in the flow chart shown in FIG. 5 ; [0163] FIG. 32 illustrates SNP appearing on the genome; [0164] FIG. 33 illustrates the format of an input file having genotype data described to enter them into a program for linkage disequilibrium analysis; [0165] FIG. 34 illustrates IUB codes; [0166] FIG. 35 illustrates the format of an input file having the physical position of each locus described to enter it into a program for linkage disequilibrium analysis; [0167] FIG. 36 illustrates some cases where only two alleles are actually present, but three or more alleles are misjudged to be present; [0168] FIG. 37 illustrates a case where a probe reacts with two locations on the genome; [0169] FIG. 38 illustrates a case where a sample population is a combination of two different populations; [0170] FIG. 39 illustrates a case where contamination from a different sample has occurred; [0171] FIG. 40 illustrates a special individual; [0172] FIG. 41 illustrates an individual having many missing data; and [0173] FIG. 42 illustrates a locus having many missing data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0174] The best embodiment to carry out the inventive data input support system for gene analysis will be described below in detail referring to the appended drawings. FIGS. 1 to 31 illustrate the embodiment of the present invention, wherein a portion with an identical symbol represents the same matter and the basic constitution and operation are the same through the figures. Configuration of Genotype Data Input Support System [0175] FIG. 1 shows a functional block diagram outlining the internal configuration of a genotype data input support system constructed in an embodiment of the present invention. The genotype data input support system comprises a program DB 100 where the features of various programs used in statistical gene analysis are saved, a display device 101 for displaying input data and supported interpretation results therefor, a key board 102 and a pointing device 103 such as a mouse for operation such as selection of individuals or loci from the displayed data or the like, a CPU 104 for carrying out necessary arithmetic processing, control processing and the like, a program memory 105 for storing the programs necessary to processing in the CPU 104 , and a data memory 106 for storing data necessary to processing in the CPU 104 . [0176] The program memory 105 contains: a specified physical position report processing section 107 for execution of the above Function 1; a physical position order report processing section 108 for execution of Functions 2-1 and 2-2; a physical positions overlap report processing section 109 for execution of Function 3; a similar locus name report processing section 110 for execution of Functions 4-1 and 4-2; a genotype report processing section 111 for execution of Functions 5-1, 5-2, 5-3, 5-4 and 5-5; a population name report processing section 112 for execution of Functions 6-1, 6-2, 6-3 and 6-4; an allele number report processing section 113 for execution of Functions 7-1, 7-2, 7-3, 7-4, 7-5, 7-6, 7-7, 7-8, 7-9 and 7-10; a monomorphism report processing section 114 for execution of Functions 8-1 and 8-2; an in/del report processing section 115 for execution of Functions 9-1 and 9-2; a dual site reaction report processing section 116 for execution of Functions 10-1 and 10-2; a plural populations report processing section 117 for execution of Function 11; a contamination report processing section 118 for execution of Functions 12-1 and 12-2; a special individual report processing section 119 for execution of Functions 13-1 and 13-2; a missing individual report processing section 120 for execution of Functions 14-1 and 14-2; and a reported/corrected items display processing section 121 for execution of Function 15. Additionally, the genotype report processing section 111 comprises a symbol genotype report processing section 122 for execution of the above Functions 5-1 and 5-2, a character string genotype report processing section 123 for execution of Functions 5-3 and 5-4, and an unexpected genotype report processing section 124 for execution of Function 5-5; the population name report processing section 112 comprises a specified population name report processing section 125 for execution of the above Function 6-1, a falsely described population name report processing section 126 for execution of Functions 6-2 and 6-3, and an unexpected population name report processing section 127 for execution of Function 6-4; and the allele number report processing section 113 comprises a multiple alleles report processing section 128 for execution of the above Functions 7-1, 7-2 and 7-3, a falsely described heterozygosis report processing section 129 for execution of Functions 7-4 and 7-5, a missing blank report processing section 130 for execution of Functions 7-6 and 7-7, a heterozygosis blank report processing section 131 for execution of Functions 7-8 and 7-9, and an irregular blank character report processing section 132 for execution of Function 7-10. [0177] The data memory 106 comprises program data 133 containing the features of programs used in statistical gene analysis and input data 134 used as input data for the programs. [0178] FIG. 2 shows the data structure of the program data 133 contained in the data memory 106 . The data structure called AnalysisProgram comprises: a program name 200 ; a physical position specification flag 201 indicating if the physical positions of loci are required as input data; a physical position order flag 202 indicating if the loci are assumed to be arranged in the order of their physical positions; a patient/healthy population flag 203 indicating if both patients and healthy persons are assumed to be used; a multiple alleles exclusion flag 204 indicating if two alleles are assumed in each locus; a monomorphism exclusion flag 205 indicating if every locus is assumed to be polymorphic; and an in/del exclusion flag 206 indicating if nothing but A, T, G or C is assumed to appear as allele. [0179] FIG. 3 shows the data structure of the input data 134 contained in the data memory 106 . Hereinafter, unspecified data items will have a null value. The data structure called InputData comprises input data name 300 , locus data 301 and individual data 302 . The locus data 301 retains the data in the arrangement of a data structure called LocusData as described below. The individual data 302 retains the data in the arrangement of a data structure called IndividualData as described below. [0180] The data structure LocusData comprises each locus name 303 , its physical position 304 and an experimental protocol 305 used to determine the genotype at each locus for the number of loci, integer i. [0181] The data structure IndividualData comprises: an individual identifier 306 for each individual; a population name 307 indicating the name of the population to which the individual belongs; a genotype data 308 indicating respective genotypes which the individual has at respective loci; and an original character string 309 in the input data, for the number of individual samples, integer j. The genotype data 308 represents an array for storing genotype data interpreted by separating the input data 309 into compartments with blank characters, and has the number of elements equal to the number of elements, integer i, in the locus data 301 . Operation of Genotype Data Input Support System [0182] Next, processings executed in the genotype data input support system of the present embodiment will be now described which system is configured as described above. FIG. 4 shows a flow chart illustrating the processing flow in the genotype data input support system. In FIG. 4 , data corresponding to a program specified by a user are first loaded from the program DB 100 (step 400 ). The data loaded here are retained as the program data 133 in the data memory 106 . Input data used for the program and each experimental protocol for each locus are then loaded (step 401 ). The data loaded here are retained as the input data 134 in the data memory 106 . Thereafter, errors in the input data are detected and reported, and user input is accepted to produce a modified version of the input data (step 402 ). These processings are executed using the processing sections 107 to 132 contained in the program memory 105 , which will be described in detail referring to FIG. 5 . [0183] Next, the processing for checking and reporting if there are errors in the input data, and accepting user input, which is executed in step 402 in FIG. 4 , will be detailed referring to a detailed flow chart shown in FIG. 5 . First of all, it is checked and reported if the physical positions of loci are specified, using the specified physical position report processing section 107 (step 500 ). If the physical position specification flag 201 in the program data 133 is TRUE, and the physical position 304 of the locus data 301 in the input data 134 is not specified, an error is judged to be present and it is displayed on the screen as shown in FIG. 9 . [0184] Next, it is checked if the input loci are arranged in the order of their physical positions, and the results are reported and corrected (step 501 ), using the physical position order report processing section 108 . If the physical position order flag 202 in the program data 133 is TRUE, the physical position 304 of the locus data 301 in the input data 134 is investigated one after another. If some specified physical positions present a reversed magnitude correlation, an error is judged to be present and it is displayed on the screen as shown in FIG. 10 . If the user ticks 1000 , the data on the relevant two loci in the locus data 301 , the genotype data 308 , and the input data 309 are exchanged to produce a modified version of the input data. [0185] Next, it is checked and reported if the physical positions of the loci are overlapped, using the physical positions overlap reporting/processing section 109 (step 502 ). The physical position 304 of the locus data 301 in the input data 134 is investigated one after another, and if some of the physical positions have the same number, an error is judged to be present and it is displayed on the screen as shown in FIG. 11 . [0186] Next, it is checked if a locus name is falsely described, and the results are reported and corrected (step 503 ), using the similar locus name report processing section 110 . As described in the above Function 4-1, it is checked if there is a locus in which the genotype data 308 in the input data 134 are unspecified in every individual and there is a locus in which the physical position 304 is unspecified. If such a set of loci is present, and the loci have similar names, an error is judged to be present and it is displayed on the screen as shown in FIG. 12 . If the user ticks 1100 , the following operation is executed to produce a modified version of the input data. The physical position 304 of a locus having its genotype data 308 unspecified is transcribed for the other locus having its physical position 304 unspecified. Thereafter, the data on the locus having its genotype data 308 unspecified is deleted from the locus data 301 , the genotype data 308 , and the input data 309 . [0187] Next, it is checked if an unexpected genotype is present, and the results are reported and corrected (step 504 ), using the genotype reporting/processing section 111 . This processing will be described in detail referring to FIG. 6 . [0188] Next, it is checked if a population name is erroneous, and the results are reported and corrected (step 505 ), using the population name reporting/processing section 112 . This processing will be described in detail referring to FIG. 7 . [0189] Next, it is checked if a locus having three or more alleles is present, and the results are reported and corrected (step 506 ), using the allele number reporting/processing section 113 . This processing will be described in detail referring to FIG. 8 . [0190] Next, it is checked if a monomorphic locus is present, and the results are reported and corrected (step 507 ), using the monomorphism reporting/processing section 114 . If the monomorphism exclusion flag 205 in the program data 133 is TRUE, and the genotype data 308 in the input data 134 is not polymorphic, an error is judged to be present and it is displayed on the screen as shown in FIG. 24 . If the user ticks 2400 , the data on the relevant locus is deleted from the locus data 301 , the genotype data 308 , and the input data 309 to produce a modified version of the input data. [0191] Next, it is checked if a locus containing in/del polymorphism is present, and the results are reported and corrected (step 508 ), using the in/del reporting/processing section 115 . If the in/del exclusion flag 206 in the program data 133 is TRUE, and the genotype data 308 in the input data 134 is in/del polymorphic, an error is judged to be present and it is displayed on the screen as shown in FIG. 25 . If the user ticks 2500 , the data on the relevant locus is deleted from the locus data 301 , the genotype data 308 , and the input data 309 to produce a modified version of the input data. [0192] Next, it is checked if there is a locus heterozygous in extremely many individuals, and the results are reported and corrected (step 509 ), using the dual site reaction reporting/processing section 116 . For each locus, the number rate of individuals having the heterozygous locus in the total individuals (heterozygosity), the occurrence probability of the locus with an observed heterozygosity (P value in the Hardy-Weinberg equilibrium test) or the like is used to evaluate the abundance of individuals heterozygous at the locus. If there is a locus heterozygous in extremely many individuals, it is displayed on the screen as shown in FIG. 26 . The numeral 2600 in the screen display shows the genotype frequency for the locus summarized from the genotype data 308 for each individual. If the user ticks 2601 , the data on the relevant locus is deleted from the locus data 301 , the genotype data 308 , and the input data 309 to produce a modified version of the input data. [0193] Next, it is checked and reported if there is a locus homozygous in extremely many individuals (step 510 ), using the plural populations report processing section 117 . For each locus, the number rate (homozygosity) of individuals having the homozygous locus in the total individuals, the occurrence probability (P value in the Hardy-Weinberg equilibrium test) of the locus with an observed homozygosity or the like is used to evaluate the abundance of individuals homozygous at the locus. If there is a locus homozygous in extremely many individuals, it is displayed on the screen as shown in FIG. 27 . The numeral 2700 in the screen display shows the genotype frequency for the locus summarized from the genotype data 308 for each individual. [0194] Next, it is checked if there is an individual having extremely many heterozygous loci, and the results are reported and corrected (step 511 ), using the contamination report processing section 118 . For each individual, the number rate of the heterozygous loci in the total loci, the occurrence probability (P value) of the individual with an observed number rate or the like is used to evaluate the abundance of heterozygous loci. If there is an individual having extremely many heterozygous loci, it is displayed on the screen as shown in FIG. 28 . The numeral 2800 in the screen display shows the number rate of heterozygous loci summarized from the genotype data 308 . If the user ticks 2801 , the data on the relevant individual is deleted from the individual data 302 to produce a modified version of the input data. [0195] Next, it is checked if there is an individual having extremely many homozygous loci, and the results are reported and corrected (step 512 ), using the special individual reporting/processing section 119 . For each individual, the number rate of the homozygous loci in the total loci, the occurrence probability (P value) of the individual with an observed number rate or the like is used to evaluate the abundance of homozygous loci. If there is an individual having extremely many homozygous loci, it is displayed on the screen as shown in FIG. 29 . The numeral 2900 in the screen display shows the number rate of homozygous loci summarized from the genotype data 308 . If the user ticks 2901 , the data on the relevant individual is deleted from the individual data 302 to produce a modified version of the input data. [0196] Next, it is checked if there is an individual having many missing data, and the results are reported and corrected (step 513 ), using the missing individual reporting/processing section 120 . The number rate of the missing data in the total loci is used to evaluate the abundance of missing data. If there are far more missing data than a predetermined reference level, it is displayed on the screen as shown in FIG. 30 . The numeral 3000 in the screen display shows the number rate of missing data summarized from the genotype data 308 . If the user ticks 3001 , the data on the relevant individual is deleted from the individual data 302 to produce a modified version of the input data. [0197] Next, the reported items and items for each of which a modified version of the input data was produced in steps 500 to 513 are listed up and displayed on the screen as shown in FIG. 31 (step 514 ), using the reported/corrected items display processing section 121 . The numeral 3100 in the screen display shows an outline of the respective reported items and if they were corrected, respectively. The numeral 3101 in the screen display shows the number of reported items and the number of reported items for each of which, however, a modified version of the input data was not produced. [0198] Next, the processing for checking if there is an unexpected genotype, and reporting and correcting the results, which is executed in step 504 in FIG. 5 , will be detailed referring to a detailed flow chart shown in FIG. 6 . It is first checked if a symbol such as “*” (asterisk) is specified as genotype, and the results are reported and corrected (step 600 ), using the symbol genotype report processing section 122 . If there is such a genotype, it is displayed on the screen as shown in FIG. 13 . If the user ticks 1300 , “0” is entered in the relevant element in the genotype data 308 and the input data 309 to produce a modified version of the input data. [0199] Next, it is checked if a character string of two alleles is specified as genotype data, and the results are reported and corrected (step 601 ), using the character string genotype report processing section 123 . If there is such a genotype, it is displayed on the screen as shown in FIG. 14 . If the user ticks 1400 , a correct heterozygous genotype is entered in the relevant element in the genotype data 308 and the input data 309 to produce a modified version of the input data. [0200] Next, it is checked and reported if an unexpected character string is specified as genotype data (step 602 ), using the unexpected genotype report processing section 124 . If there is such a genotype, it is displayed on the screen as shown in FIG. 15 . [0201] Next, the processing for checking if a population name is erroneous, and reporting and correcting the results, which is executed in step 505 in FIG. 5 , will be detailed referring to a detailed flow chart shown in FIG. 7 . It is first checked and reported if a population name is specified (step 700 ), using the specified population name report processing section 125 . If the patient/healthy population flag 203 in the program data 133 is TRUE, and the population name 307 of the individual data 302 in the input data 134 is not specified, an error is judged to be present and it is displayed on the screen as shown in FIG. 16 . [0202] Next, it is checked if “Case” or “Control” is specified as population name, or an erroneously spelled name for “Patient” or “Normal” is specified where capital and/or small letters are wrongly used, and the results are reported and corrected (step 701 ), using the falsely described population name reporting/processing section 126 . If there is an individual with such a population name specified, it is displayed on the screen as shown in FIG. 17 . If the user ticks 1700 , a correct population name is entered in the population name 307 to produce a modified version of the input data. [0203] Next, it is checked and reported if an unexpected character string is specified as population name (step 702 ), using the unexpected population name report processing section 127 . If there is an individual with such a population name specified, it is displayed on the screen as shown in FIG. 18 . [0204] Next, the processing for checking if there is a locus having three or more alleles, and reporting and correcting the results, which is executed in step 506 in FIG. 5 , will be detailed referring to a detailed flow chart shown in FIG. 8 . It is first checked if missing data is accidentally described as blank characters (a one-byte space, tab or the like), and the results are reported and corrected (step 800 ) as described in Function 7-6, using the blank missing report processing section 130 . If such a description has occurred, it is displayed on the screen as shown in FIG. 21 . It is displayed with emphasis that genotypes are shifted out of place ( 2100 ). If the user ticks 2101 , the following operation is executed to produce a modified version of the input data. The genotype data 308 for a locus that has caused such a shift is replaced by “0”, and each subsequent locus undergoes transcription of the genotype data 308 for its direct preceding locus in the genotype data 308 . Also, the relevant data in the input data 309 is replaced by “0”. [0205] It is checked if a heterozygous genotype is accidentally described as two alleles separated by a one-byte space, and the results are reported and corrected (step 801 ) as described in Function 7-8, using the heterozygosis blank report processing section 131 . If such a description has occurred, it is displayed on the screen as shown in FIG. 22 . It is displayed with emphasis that genotypes are shifted out of place ( 2200 ). If the user ticks 2201 , the following operation is executed to produce a modified version of the input data. The genotype data 308 for a locus that has caused such a shift is replaced by a correct heterozygous genotype, and each subsequent locus undergoes transcription of the genotype data 308 for its direct following locus in the genotype data 308 . In addition, the last locus (its locus name not specified and having a specified genotype only in the individual having a third or higher-numbered most frequent allele in common) is deleted from the locus data 301 and the genotype data 308 . Also, the relevant data in the input data 309 is replaced by the correct heterozygous genotype. [0206] It is checked if a heterozygous genotype is falsely described, and the results are reported and corrected (step 802 ) as described in Function 7-4, using the falsely described heterozygosis reporting/processing section 129 . If there is a locus with a heterozygous genotype falsely described, it is displayed on the screen as shown in FIG. 20 . The numeral 2000 in the screen display shows a genotype frequency for the locus summarized from the genotype data 308 for each individual. If the user ticks 2001 , the data on the relevant locus is deleted from the locus data 301 and the genotype data 308 , and the input data 309 to produce a modified version of the input data. If the user ticks 2002 , a correct heterozygous genotype is entered in the genotype data 308 and the input data 309 to produce a modified version of the input data. If the user ticks 2003 , nothing is done. Ticks in 2001 , 2002 and 2003 are exclusive to each other, and two or more ticks must not be present. [0207] It is checked if a locus having three or more alleles is present, and the results are reported and corrected (step 803 ) as described in Function 7-1, using the multiple alleles reporting/processing section 128 . If the multiple alleles exclusion flag 204 in the program data 133 is TRUE, or the experimental protocol 305 in the input data 134 can discriminate only two alleles, the genotype data 308 in the input data 134 are searched for a locus having three or more alleles. If such a locus is present, it is displayed on the screen as shown in FIG. 19 . The numeral 1900 on the display screen is displayed if the multiple alleles exclusion flag 204 in the program data 133 is TRUE. The numeral 1901 shows an allele frequency for the locus summarized from the genotype data 308 for each individual. The numeral 1902 is displayed if the experimental protocol 305 in the input data 134 can discriminate only two alleles. If the user ticks 1903 , the data on the relevant locus is deleted from the locus data 301 and the genotype data 308 , and the input data 309 to produce a modified version of the input data. If the user ticks 1904 , in each individual having a third or higher-numbered most frequent allele, the genotype for the relevant locus in the genotype data 308 and the input data 309 is replaced by a genotype containing the most frequent allele to produce a modified version of the input data. If the user ticks 1905 , nothing is done. Ticks in 1903 , 1904 and 1905 are exclusive to each other, and two or more ticks must not be present. [0208] Next, it is checked and reported if a blank character is used irregularly (step 804 ) as described in Function 7-10, using the irregular blank character reporting/processing section 132 . In investigating each individual for input data 309 , if two or more kinds of blank characters are used as break character for the input data, or two or more blank characters appear in succession, or such characters (a double-byte space or the like) as may be interpreted as either blank character or data are used, blank characters are judged to be used irregularly. If it happens, it is displayed on the screen as shown in FIG. 23 . The numeral 2300 expressly shows the types and locations of the blank characters in the input data. [0209] Herein, only the IUB coding system has been described, but the format of data opened by the HapMAP project can also employ the sections used here consisting of: a physical position order report processing section 108 ; a physical positions overlap report processing section 109 ; a symbol genotype report processing section 122 , a character string genotype report processing section 123 , and an unexpected genotype report processing section 124 within a genotype report processing section 111 ; a multiple alleles report processing section 128 and an irregular blank character report processing section 132 within an allele number report processing section 113 ; a monomorphism report processing section 114 ; an in/del report processing section 115 ; a dual site reaction report processing section 116 ; a plural populations report processing section 117 ; a contamination report processing section 118 ; a special individual report processing section 119 ; a missing individual report processing section 120 ; and a reported/corrected items display processing section 121 . [0210] Also, the input data format of ARLEQUIN can employ the sections used here consisting of: a symbol genotype report processing section 122 and an unexpected genotype report processing section 124 within a genotype report processing section 111 ; a falsely described population name report processing section 126 and an unexpected population name report processing section 127 within a population name report processing section 112 ; a multiple alleles report processing section 128 , a blank missing report processing section 130 and an irregular blank character report processing section 132 within an allele number report processing section 113 ; a monomorphism report processing section 114 ; an in/del report processing section 115 ; a dual site reaction report processing section 116 ; a plural populations report processing section 117 ; a contamination report processing section 118 ; a special individual report processing section 119 ; a missing individual report processing section 120 ; and a reported/corrected items display processing section 121 . [0211] Also, the input data format of LINKAGE can employ the sections used here consisting of: a symbol genotype report processing section 122 and an unexpected genotype report processing section 124 within a genotype report processing section 111 ; a multiple alleles report processing section 128 , a blank missing report processing section 130 and an irregular blank character report processing section 132 within an allele number report processing section 113 ; a monomorphism report processing section 114 ; an in/del report processing section 115 ; a dual site reaction report processing section 116 ; a plural populations report processing section 117 ; a contamination report processing section 118 ; a special individual report processing section 119 ; a missing individual report processing section 120 ; and a reported/corrected items display processing section 121 . [0212] Herein, each type of error has been described using an error made at a single locus in a single individual, but can be also described in the same manner using errors made at plural loci in plural individuals. Specifically, as an example, only a single individual (P 07 ) having many missing data is described in FIG. 30 , but plural individuals may actually have many missing data. Such a case can be dealt with similarly. Specifically, every individual having many missing data can be listed up on the illustrative display screen shown in FIG. 30 . It applies to other types of error similarly. [0213] Herein, the whole sample population has been checked in a lump using the monomorphism report processing section 114 or the plural populations report processing section 117 , but each population may be checked differently instead. Specifically, using the monomorphism report processing section 114 , for example, it may be checked as such a case if there is a locus which may be polymorphic in the healthy population, but is not polymorphic in the patient population. [0214] The data input support system for gene analysis according to the present invention has been described hereinbefore by means of specific embodiments, but the present invention is not limited thereto. Those skilled in the art could make various alterations or modifications in the constitutions and functions of the invention which may be associated with the foregoing or other embodiments, within the gist of the present invention. [0215] The data input support system for gene analysis according to the present invention is available on a computer comprising memory means, input means, display means and the like, wherein information processing consisting of detection and display of certain types of errors in the input data of genotypes can be actually achieved by use of hardware resources such as memory means, input means and display means described above. Accordingly, the system applies to a technical idea utilizing natural laws, and can be industrially utilized in medical and/or biological research institutions and the likes which are engaged in linkage disequilibrium analysis.

A data input support system is provided to preliminarily remove particular error causes when genotype data are input for a program to execute linkage disequilibrium analysis or the like. By taking advantage of limiting conditions characteristic of genotype input data and the statistical properties of the entire data set, possible errors are detected by a preprocessing program, the detected errors are associated with false descriptions causing them to report the results, user input responding to the reported results is accepted, and a modified version of the input data is output.

FIELD OF THE INVENTION The invention relates to computerized searching. More specifically, the invention relates to searching documents and displaying the results of the search based on contextual information associated with a user. BACKGROUND OF THE INVENTION Search utilities are common throughout various computing environments such as the world-wide-web and in various computer applications such as electronic mail, word processing, and other desktop applications. A large number of computer users still only enter a single search term into the search utility, because complex search queries are difficult for the average computer user to construct. As a result, the search utility often returns an overwhelming amount of data that satisfies the search query. The user manually sorts through the search results to find the desired information. To address this problem, programmers developed various mechanisms to aid computer users in constructing search queries. One such mechanism is Query by Example (QBE), which is a method of query creation that allows the computer user to search for documents based on an example in the form of a selected text string, a document name, or a list of documents. Because the QBE system formulates the actual query, QBE is easier to learn than formal query languages, such as the standard Structured Query Language (SQL), and can produce powerful searches. For example, in QBE the location of the user's cursor on a computer display can be used to determine if the user is looking at his or her calendar program. The user can highlight a term of calendar entry and ask the QBE mechanism to search for other documents containing that term. Often, the result of the QBE is displayed to the user based on a single property (e.g., a date or a keyword). For example, a document containing an exact match of the QBE term is determined to be more likely of interest to the user than a document containing a derivative of the QBE term. Accordingly, the result of the QBE is displayed to the user based upon this assumption. However, in some circumstances the user may actually be more interested in the document containing the derivative of the QBE term, because the user may have an upcoming event focused on the derivative QBE term. Basing the QBE search results on a single property often does not produce an accurate reflection of what is important to the user. SUMMARY OF THE INVENTION In one aspect, the invention features a method of organizing and presenting information to a user based on a present or past contextual setting of the user. The method includes analyzing an event associated with the user to determine a contextual setting, dynamically generating a search query based on the contextual setting, and searching at least one information source using the search query to generate a search result. Additionally, the method includes calculating an importance value for each item of the search result, sorting the items of the search result according the importance value, and displaying the sorted search result to the user. BRIEF DESCRIPTION OF THE DRAWINGS The above and further advantages of this invention may be better understood by referring to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. FIG. 1 is a block diagram of an embodiment of client-server environment within which the present invention can operate. FIG. 2 is a conceptual block diagram of a software system according to principles of the invention. FIG. 3 is a flow chart of an embodiment of a method of organizing and presenting a search result to a user according to the principles of the invention. DETAILED DESCRIPTION The present invention relates to a software application for searching, organizing, and presenting a result of a dynamically generated search query to a user of the software application. The functionality of the software application can be incorporated into existing applications such as office applications, email applications, and time management applications. Alternatively, the software application of the present invention can be a stand-alone application. The software application retrieves documents from various sources. As used herein, the term documents includes, but is not limited to, e-mail messages, meetings notices, calendar entries, task list items, instant messages, web pages, word processing files, presentation files, spreadsheet files, database records, and the like. The dynamic search query and its associated result are generated based on a contextual setting of the user. As used herein, the contextual setting for the dynamic search query refers to past, present and future events such as meetings, conference calls, video conferences and the like that are important to the user. Refining functions, which are also based on a contextual setting, operate on the returned results of the search engine to provide further values for ranking the returned search results. A contextual setting for refining refers to all of the personal information of the user, including but not limited to email, events, and documents of the user. A combiner analyzes the results of the refining functions and the search results to provide a final ordering of the search results. The software application presents the final ordering to a user. The final ordering indicates an order of importance or priority to the user. FIG. 1 shows an embodiment of a computing environment 2 in which the invention can be practiced. The computing environment 2 includes a client system 4 in communication with a server system 6 over a network 8 . The client system 4 can be any personal computer (e.g., 486, Pentium, Pentium II, Macintosh), Windows-based terminal, wireless device, information appliance, RISC Power PC, X-device, workstation, mini-computer, mainframe computer, cell phone, personal digital assistant (PDA) or other computing device that has hardware such as a display screen, one or more input devices (e.g., keypad, stylus, keyboard, mouse, touch-pad, and trackball), a processor for executing application programs, and sufficient persistent storage for storing such application programs and related information. Application programs on the client system 4 include, but are not limited to, an electronic mail client program 12 , browser software 14 , office applications 16 such as a spread sheet, a word processor, and a slide presentation, an instant messaging program 18 , a time management application 19 , and briefing software 20 . The email client program 12 , browser software 14 , office applications 16 , instant messaging program 18 , time management application 19 , and briefing software 20 can be a proprietary or commercially available program, such as Lotus WORKPLACE™ for email, time management, and briefing, Lotus Same Time for instant messaging, Microsoft Internet Explorer™ for browser software, and Microsoft WORD for word processing. The browser software 14 can incorporate a JAVA™ virtual machine for interpreting JAVA™ code (i.e., applets, scripts) and applications. The time management application 19 typically includes a calendar, communications, and task management functions. The briefing software 20 provides the functionality of the invention. The application programs execute within an operating system. Examples of operating systems supported by the client system 4 include Windows 95, Windows 98, Windows NT 4.0, Windows XP, Windows 2000, Windows CE, Macintosh, Java, LINUX, and UNIX. The client system 4 also includes a network interface (not shown) for communicating over the network 8 . The network 8 can be a local-area network (LAN), a metro-area network (MAN), or wide-area network (WAN), such as the Internet or World Wide Web. Users of the client system 4 can connect to the network 8 through one of a variety of connections, such as standard telephone lines, digital subscriber line, LAN or WAN links (e.g., T1, T3), broadband connections (Frame Relay, ATM), and wireless connections (e.g., 802.11(a), 802.11(b), 802.11(g)). In one embodiment, the server system 6 includes an instant messaging server 24 - 1 , a search server 24 - 2 , a document management and application server 24 - 3 , and an e-mail and directory server 24 - 4 (generally, server 24 ). Although shown separately, these servers 24 can be integrated in a single computing machine. Alternatively, different computing machines geographically collocated or distributed across the network 8 , can be used to implement the server 24 . Each server 24 includes programs for performing particular services and persistent storage for keeping data related to those services. The instant messaging server 24 - 1 includes software 26 for providing instant messaging services and persistent storage 28 for storing all or some of the instant messages for a predetermined period of time. Components of the search server 24 - 2 are software 30 for performing search services and persistent storage 32 for maintaining an index of searching keywords to be used in searching for documents. The document management and application server 24 - 3 includes software 34 for providing document management services. Documents managed by the document management software 34 reside in persistent storage 38 . The e-mail and directory server 24 - 4 includes software 42 for supporting email communication among users on the network 8 and software 44 for providing directory services. The email services software 42 accesses persistent storage 46 , which stores the email messages, and the directory services software 44 accesses user directory information in persistent storage 48 . In a preferred embodiment, the briefing software 20 is integrated into the time management application 19 . The briefing software 20 communicates with each of the email 12 , browser 14 , office 16 , and instant messaging 18 applications and the instant messaging server 24 - 1 , the search server 24 - 2 , the document management and application server 24 - 3 , and the e-mail and directory server 24 - 4 as required to retrieve documents related to the contextual setting of the user. When a user activates the briefing software 20 , the briefing software 20 of the client system 4 communicates over the network 8 with the server system 6 to accomplish the search and organizational activities of the invention. To communicate information across the network 8 , in one embodiment, the client and server systems 4 , 6 use standard transport protocols, such as TCP/IP and the hypertext transfer protocol (HTTP). FIG. 2 is a conceptual block diagram of an embodiment of the briefing software 20 of FIG. 1 . The briefing software 20 includes searcher software 50 , refiner software 54 , and combiner software 58 . In general the searcher 50 includes a search engine for searching through the documents 49 in response to the dynamically generated search query produced by dynamic search query generator software 52 . In some embodiments, the search engine can be a part of the search server 24 - 2 , of the time management application 19 , or of a stand-alone search engine. The searcher 50 includes a searching function for identifying documents in response to the dynamically generated search query of the invention and a ranking function for assigning search scores to each document identified by the searching function. The searcher 50 is in communication with the combiner 58 to forward a search score 51 for each document identified by the search function and with the refiner 54 to forward search result information 53 that correlates a search score to a respective document. The search result information 53 can be the documents identified by the searcher 50 or pointers to those documents. The refiner 54 includes refining functions R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 (referred to generally as refining functions R). It should be understood that the invention is not limited to six refining functions. Instead any number of refining functions can be included as part of the briefing software 20 . In general, each refining function analyzes the search result information 53 and provides a refiner score 55 for each document identified by the searcher 50 . For example, one of the refining functions R can score a document based on who receives or authors the document. Another refining function R can score based on whether the document is a calendar entry or includes an attachment. Yet another refining function can score the document based on the temporal nature of the document. Each refining function can cause an increase or decrease in the ranking of the document within the briefing view 62 . Each refining function R can be implemented as a software class that is called by the briefing software 20 while the briefing software 20 is executing. Some parameters of the refining functions can be controlled by a dynamic interest profile 66 that is associated with the user of the briefing software 20 . In general, the dynamic interest profile 66 includes various parameters related to the interests of the user. The parameters can be dynamically determined based upon the activities of the user, statically configured by the user, or be a combination of statically configured parameters and dynamically configured parameters. An example of a dynamically determined parameter is a value assigned to various authors of documents that are read by the user. As the user reads more documents authored by a particular user, the score associated with that author increases. An example of a statically configured parameter is a value that is set by the user to indicate a higher degree of relevance to the user of a receipt of a document. For example, the refining function R 1 , referred to as the “recipient importance” refining function, scores documents retrieved by the searcher 50 based on the average importance of the recipients. The average importance is calculated by querying the user's dynamic interest profile 66 to retrieve an importance value for each recipient of the document. Expressed mathematically, the recipient importance refining function R 1 can be expressed as: f ⁡ ( d ) = { 1  S  ⁢ ∑ r ∈ S ⁢ DipScore ⁡ ( r ) if ⁢ ⁢  S  > 0 0 otherwise . ( 1 ) In equation 1, S is the set of recipients for the document that is being scored by the refining function R 1 . DipScore (r) is the score associated with the recipient. This value is retrieved from the dynamic interest profile 66 of the user of the briefing software 20 . The refining function R 2 , referred to as the “author importance” refining function, scores the documents retrieved by the searcher 50 based upon who authored the document. Mathematically, the author importance refining function R 2 can be expressed as: ƒ( d )=DipScore( S )  (2). In equation 2, the DipScore (S) relates to the importance of the author or sender of a document as viewed by the user of the briefing software 20 . The dynamic interest profile 66 of the user of the briefing software 20 calculates a value DipScore (S) for certain authors of documents. The value DipScore (S) can be dynamically or manually configured in the dynamic interest profile 66 . Generally, the value of DipScore (S) is determined by the user and user's habits related to the respective author. For example, documents authored by the user's manager may be of more importance to the user than documents authored by the other attendees of the meeting. Thus, the value calculated for DipScore (S) for the user's manager is greater than the value calculated for DipScore (S) for the other attendees. The refining function R 3 , referred to as the “participant overlap” refining function, scores document that were sent by a non-meeting participant to each of the user and the meeting participants higher than documents that were sent by the non-meeting participant to only the user. Also, the participant overlap refining function R 3 scores documents that are sent by meeting participants to the user or that were sent to the meeting participants by the user higher than documents that were not sent to or by meeting participants. For example, an email that was sent to a meeting participant is more likely to be relevant to the upcoming meeting when compared to an email that was sent to non-meeting participant. The participant overlap refining function R 3 can be expressed mathematically as: f ⁡ ( d ) =  P ⋂ ( N ⋃ S )   P ⋃ N ⋃ S  . ( 3 ) In equation 3, P represents the set of meeting participants, N represents the set of recipients of the document being scored, and S represents the author or sender of the document. The resulting score generated by the participant overlap refining function is associated with the document for use by the briefing software 20 . The refining function R 4 , referred to as the “calendar entry” refining function, scores the documents returned by the searcher 50 based on whether the document is a calendar entry. In one embodiment, the calendar entry refining function R 4 increases the relevance of the document if the document is a calendar entry. For example, when the document is a calendar entry a scoring factor is applied to the document; however, if the document is not a calendar entry then the scoring factor is not applied. Expressed mathematically, the calendar entry refining function R 4 can be viewed as: f ⁡ ( d ) = { 1 if ⁢ ⁢ the ⁢ ⁢ document ⁢ ⁢ is ⁢ ⁢ a ⁢ ⁢ calendar ⁢ ⁢ entry 0 otherwise . ( 4 ) This refining function accounts for the fact that upcoming events in the users calendar are important to the user. Similar to the calendar entry refining function R 4 , the briefing software 20 includes the “attachment included” refining function R 5 that scores the documents returned by the search engine based on whether the document includes an attachment. In one embodiment, the attachment included refining function R 5 applies a scoring factor to the document when the document includes an attachment. Conversely, when the document does not include an attachment, the attachment refining function R 5 does not apply the scoring factor to the document. A mathematical expression of the attachment included refining function R 5 can be: f ⁡ ( d ) = { 1 if ⁢ ⁢ the ⁢ ⁢ document ⁢ ⁢ has ⁢ ⁢ an ⁢ ⁢ attachment 0 otherwise . ( 5 ) The refining function R 6 , referred to as the “time-based” refining function, scores the documents returned by the searcher 50 based on temporal parameters of the documents. In one embodiment, the time-based refining function R 6 scores the documents based on when the document was created or on the time of the occurrence of the document (i.e., the time the document was received, the last time the document was modified, or the last time the document was accessed). Often documents that are created closer in time to the upcoming event are more relevant to the event and should be scored higher when compared to documents created two months prior to the upcoming event. For example, a document created one day prior to an upcoming meeting typically includes information that is up to date. Therefore, the score applied to the one-day old document is greater than the score applied to a document that was created two weeks ago. In one embodiment, the time-based refining function R 6 is expressed mathematically as: f ⁡ ( d ) = 1  t e - t d  + 1 . ( 6 ) In equation 6, t e represents the time of the upcoming or past event and t d represents the time of creation of the document or the time of occurrence of the document. The resulting score generated by each of the refining functions R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are associated with the document for use by the combiner 58 . Although shown as having six refining functions R, the refiner 54 can include various numbers of refining functions R. Various combinations of the refining functions R are applied to the documents returned from the search 50 . It is not required that every refining function R generate a score for each document returned by the searcher 50 . In one embodiment, the combiner 58 is a weighting algorithm that combines the scores returned from both the searcher 50 and the refiner 54 for each document. The combiner 58 applies a weighting algorithm having at least one weighting factor related to the contextual setting to each of the scores. The weighting applied to each of the refining function scores and the search result score can be dynamically determined based on the history of the user or manually set using the dynamic interest profile 66 of the user. The combining function produces the final rankings of the documents that are used to generate the briefing view 62 . FIG. 3 depicts an embodiment of a method 100 of operation of the briefing software 20 . To generate the briefing view 62 , the user launches the time management application 19 (e.g., Lotus WORKPLACE™) and selects the “briefing view” from the view menu of the time management application 19 . When the briefing view is selected, the dynamic query generation software 52 dynamically constructs (step 110 ) a search query based upon information within the time management application 19 . For example, the dynamic query generation software 52 analyzes a calendar entry to determine the contextual setting for the user. In addition to calendar entries, the briefing software 20 can analyze email, instant messages, thread postings, task list items, reminder notices, or a combination thereof to dynamically generate the search query. As an illustrative example, if a calendar entry reads “meet to discuss Windows patch deployment adoption” and lists the participants as Joe Smith, John Price, Fred Randolf, the resulting dynamically generated search query is: text:meet, text:to, text:discuss, text:windows, text:patch, text:deployment, text:adoption, author:“joe smith”, author:“john price”, author:“fred randolf” sentto:“joe smith”, sentto:“john price”, sendto:“fred randolf.” In this example, text:x indicates that the body or subject of any returned document should contain text x, author:x indicates that the author of any returned document should contain text x, and sendto:x indicates that any returned document should have been sent to recipient x. In one embodiment, the dynamically generated search query is displayed to the user to allow the user to modify the dynamically generated search query. The briefing software 20 requests (step 120 ) a search of the documents 49 accessible by the user using the dynamically generated search query. Documents fulfilling any subset of the dynamically generated search query conditions are returned by the searcher 50 and ranked based on a ranking algorithm associated with the searcher 50 . Generally the searcher 50 scores documents based on the number of fulfilled search criteria; documents with more conditions fulfilled score higher than those documents with fewer fulfilled conditions. For example, referring to the previous exemplary search query an email (i.e., document D 1 ) authored by John Price sent to Fred Randolph having a subject line “widows patch” scores higher than an email (i.e., document D 2 ) authored by John Price sent to Joe Smith having a subject line “let's have lunch” having an attachment titled “windows patch deployment meeting”. The refiner 54 refines (step 130 ) the search results returned from the searcher 50 . The various refining functions R of the refiner 54 operate on the search results to score each retrieved document. After any one or combination of refining functions operate on each document returned by the searcher 50 , the combiner 58 combines (step 140 ) the scores produced by the search engine and the scores produced by the refining function to create an importance value for each document. After the final rankings are set, the briefing software 20 displays (step 150 ) the final result to the user. The following example is provided to illustrate various features and advantages of the invention. Referring back to the search results above, the searcher 50 scores document D 1 at 70.0 and D 2 at 60.0. However, applying various refining functions R of the refiner 54 and using the refining results 55 in the combiner 58 alters the final rankings in the briefing view 62 . In this example, the briefing software 20 applies the refining functions R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 to the documents returned from the searcher 50 . Consider that each document was created at roughly the same time; therefore, the time based refining function R 6 does not influence the final rankings in the briefing view 62 . Similarly, the calendar entry refining function R 4 does not influence the final rankings, because neither document D 1 or D 2 is a calendar entry. Each document has the same author; therefore, the author importance refining function R 2 does not influence the ranking. Neither document D 1 nor document D 2 is from or sent to any other meeting participant than John Price so the participant overlap refining function R 3 returns 0.0 for each of the documents D 1 , D 2 and therefore does not influence the final ranking. However, documents D 1 and D 2 have different recipients that are of greater and lesser importance to the user. Applying the recipient importance refining R 1 returns different values for the documents D 1 , D 2 . For example, Fred Randolph (recipient of document D 1 ) is the administrative assistant of John Price while Joe Smith (recipient of document D 2 ) is the supervisor of John Price. Accessing the dynamic interest profile 66 of the user reveals that Fred Randolph has a recipient importance value of 10.0 and Joe Smith has a recipient importance value of 90.0. The document D 2 also includes an attachment, while document D 1 does not. Therefore the attachment refining function R 5 returns a score of 0.0 for document D 1 and a score of 1.0 for document D 2 . The combiner 58 uses a weighted linear combination function to calculate the final score for the documents D 1 , D 2 . In the weighted linear combination function, the searcher scores 51 are given a weight of 1.0, the recipient importance refiner R 1 is given a weight of 0.1 and the attachment refiner R 5 is given a weight of 3.0. For clarity, assume that all refining functions R that returned identical values for the two documents D 1 , D 2 are ignored by the combiner 58 . The combiner 58 assigns document D 1 a final score of 71.0 which is calculated as shown in equation 7: ((1.0×70.0)+(0.1×10.0)+(3.0×0.0))  (7) The combiner assigns document D 2 a final score of 72.0 that is calculated as shown in equation 8: ((1.0×60.0)+(0.1×90.0)+(3.0×1.0))  (8) Therefore in the briefing view 62 the document D 2 is displayed as ranking higher than document D 1 . As shown, the operation of the refiner 54 and the combiner 58 reverse the final rankings of the documents D 1 and D 2 when compared to the searcher 50 alone. Although described using a single calendar entry, the principles of the invention can be applied to multiple calendar entries and multiple other documents depending on the preference of the user. For example, if the user has multiple meetings scheduled for a particular day, the text for each of those meetings is used to create a compound search. In the returned search results, the documents related to the next scheduled meeting are displayed first. This concept can be applied to generate a “sliding window” of important documents related to the upcoming meetings of the user. To implement the sliding window concept, the user configures the briefing software 20 to run at predetermined intervals (e.g., every 15 minutes) so the resulting briefing view 62 generated by the briefing software 20 updates continually. Another example of the sliding window concept includes not only upcoming events for the user, but includes recently completed events. A meeting that the user just attended may still be important to the user because, for example, the user was assigned action items as a result of the meeting. The briefing view 62 can include documents related to the recently completed event. While the invention has been shown and described with reference to specific preferred embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the following claims. For example, although described as a method and data file the invention can be embodied as a computer readable medium (e.g., compact disk, DVD, flash memory, and the like) that is sold and distributed in various commercial channels. Also, the computer readable instructions contained on the computer readable medium can be purchased and download across a network (e.g., Internet). Additionally, the invention can be embodied as a computer data signal embodied in a carrier wave for organizing and presenting information to a user.

A method of generating a context-inferenced search query and of sorting a result of the query is described. The method includes analyzing an event associated with the user to determine a contextual setting, dynamically generating a search query based on the contextual setting, and searching at least one information source using the search query to generate a search result. Additionally, the method includes calculating an importance value for each item of the search result, sorting the items of the search result according the importance value, and displaying the sorted search result to the user.

RELATED APPLICATION [0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/287,690, filed Jan. 27, 2016, the entire disclosure of which is hereby incorporated herein by reference. TECHNICAL FIELD [0002] In various embodiments, the present invention relates to the formation and processing of wires composed of high-entropy alloys and/or multi-principal element alloys. BACKGROUND [0003] High-entropy alloys (HEAs) are typically defined as alloys containing 5 or more constituent elements each with a concentration between 5 and 35 atomic %. The defining feature of HEAs over other complex alloys is that, due to their high entropy of mixing, they essentially consist of a simple solid solution phase, rather than forming one or more intermetallic phases. Various HEAs exhibit one or more superior mechanical properties such as yield strength, fracture toughness, and fatigue resistance. Multi-principal element alloys (MPEAs) are similar to HEAs but may include as few as four constituent elements. However, many HEAs and MPEAs, particularly those that include one or more refractory metals (e.g., Nb, Mo, etc.) are quite difficult to fabricate and utilize due to their high strength and limited ductility. Because diffusion tends to be quite slow in HEAs and MPEAs, bulk quantities of these materials are also often quite difficult to homogenize. These and similar issues have limited the widespread adoption of many HEAs and MPEAs. [0004] Additive manufacturing, or three-dimensional (3D) printing, is a widely utilized technique for rapid manufacturing and rapid prototyping. In general, additive manufacturing entails the layer-by-layer deposition of material by computer control to form a three-dimensional object. Most additive manufacturing techniques to date have utilized polymeric or plastic materials as raw materials, as such materials are easily handled and melt at low temperatures. Since additive manufacturing involves the melting of only small amounts of material at a time, the process has the potential to be a useful technique for the fabrication of large, complex structures composed of HEAs or MPEAs. Specifically, the small melt pool of material utilized at any point in time during an additive manufacturing process may result in small molten volumes of substantially homogenous alloy material that cool at a rate sufficient to stabilize the homogenized composition of the alloy. That is, the small size of the melt pool should promote mixing of the alloy constituents, and the high cooling rate should limit segregation, promoting formation of a substantially homogeneous alloy. [0005] Unfortunately, additive manufacturing of metallic materials is not without its challenges. When metallic precursor materials for additive manufacturing possess significant amounts of oxygen or other volatile species (e.g., calcium, sodium, antimony, phosphorus, sulfur, etc.), the melting of such materials may result in sparking, blistering, and splattering (i.e., ejection of small pieces of the materials themselves). In addition, even if a three-dimensional part is fabricated utilizing such materials, the part may exhibit excessive porosity, cracking, material splatter, and insufficient density and machinability. [0006] In view of the foregoing, there is a need for improved precursor materials for the additive manufacturing of metallic parts, and in particular parts composed of HEAs and MPEAs. SUMMARY [0007] In accordance with various embodiments of the present invention, wires for use as feedstock for additive manufacturing processes of HEAs or MPEAs are fabricated from powders of the various constituent elements of the alloy. The powders are formed utilizing one or more techniques that minimize or substantially reduce the amount of oxygen and other volatile elements within the powders. In this manner, the amount of such volatile species within the wire is minimized or reduced. For example, various powders may be formed and/or treated via a hydride/dehydride process, plasma densification, and/or plasma atomization, and the powders may have low concentrations of volatile species such as oxygen (e.g., oxygen contents lower than 300 ppm, or even lower than 100 ppm). Various powders or powder precursors may even be combined with one or more materials (e.g., metals) having a higher affinity for oxygen (e.g., calcium, magnesium, etc.), deoxidized at high temperature, and then separated from the high-oxygen-affinity material via, e.g., chemical leaching, as detailed in U.S. Pat. No. 6,261,337, filed on Aug. 19, 1999 (the '337 patent), the entire disclosure of which is incorporated by reference herein. [0008] In addition, various embodiments of the present invention feature HEA or MPEA feedstock wire fabricated using powders of the alloy's constituent elements (or binary or ternary mixtures or alloys thereof) that have different particle sizes and/or volumetric shapes (or morphologies) in order to minimize the amount of inter-particle space within the wire. Since such space may include or trap oxygen or other volatile species within the wire, minimization of the space typically results in the substantial reduction of such species within the wire. Such wire may subsequently be melted (via, e.g., application of an electron beam or a laser) to fabricate a three-dimensional part utilizing an additive-manufacturing technique. For example, in various embodiments of the present invention, tungsten and/or molybdenum powders are plasma densified and thus are composed of substantially spherical particles. Such powders are mixed with multiple other powders formed utilizing hydride/dehydride processes to form one or more HEAs or one or more MPEAs. As known in the art, hydride/dehydride processes involve the embrittlement of a metal via hydrogen introduction (thereby forming a hydride phase), followed by mechanical grinding (e.g., ball milling) and dehydrogenation (e.g., heating in a vacuum); the resulting particles tend to be highly angular and flake-like due to the grinding process. In various embodiments of the present invention, such non-spherical powder particles are mixed with substantially spherical plasma-densified particles of other constituent metals, thereby maximizing particle packing efficiency and minimizing the amount of trapped volatile species within the final wire. [0009] In accordance with various embodiments of the invention, the HEA or MPEA feedstock wire is formed by, e.g., drawing and/or other mechanical deformation (e.g., swaging, pilgering, extrusion, etc.) of a preform that has the shape of, for example, a rod or a bar. The resulting wire may be utilized in an additive manufacturing process to form a three-dimensional part composed of the alloy of the wire. In exemplary embodiments, the wire is fed toward a movable platform, and the tip of the wire is melted by, e.g., an electron beam or a laser. The platform moves such that the molten wire traces out the pattern of a substantially two-dimensional slice of the final part; in this manner, the final part is fabricated in layer-by-layer fashion via melting and rapid solidification of the wire. [0010] Wire in accordance with embodiments of the invention may also be utilized in a variety of different wire-fed welding applications (e.g., MIG welding, welding repair) in which an electric arc is struck between the wire and a workpiece, causing part of the wire to fuse with the workpiece. [0011] Various embodiments of the invention fabricate and utilize HEAs including, consisting essentially of, or consisting of five or more elements such as five or more of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. Exemplary HEAs in accordance with embodiments of the invention include MoTaTiZrHf, MoTaNbTiZrHf, MoTaNbWTiV, NbTiHfZrCr, NbTiHfZrV, and NbTaMoWX, where X is one or more of V, Cr, Ti, Zr, Hf, and Al. Various embodiments of the invention fabricate and utilize multi-principal element alloys (MPEAs) that include, consist essentially of, or consist of four or more elements such as four or more of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. Unless otherwise indicated, references herein to HEAs and/or the fabrication and use of HEAs containing five or more elements also encompass and are applicable to MPEAs having four or more elements and their fabrication and use. For each alloy in accordance with embodiments of the invention, the various elemental constituents may be present within the alloy in equiatomic or substantially equiatomic proportions. In other embodiments, one or more, or even each, of the elemental constituents is present within the alloy at an atomic concentration between 5% and 35%. In various embodiments, two or more of the elemental constituents are present in the alloy at approximately equal concentrations, and those concentrations are different from that of one or more other elemental constituents in the alloy. For example, two of the elemental constituents may be present in the alloy at approximately 40% (atomic), while the other 20% of the alloy is composed of the two or more other constituents, which may or may not be present in concentrations that are approximately equal to each other. [0012] As utilized herein, the term “substantially spherical” means spherical to within ±10%, and in some embodiments, ±5% in any direction—i.e., the eccentricity in any direction does not exceed 5% or 10%. As utilized herein, “non-spherical” means elongated with an aspect ratio of at least 2:1, acicular, having at least one flat surface (e.g., a flake with two opposed flat surfaces), having at least one corner or vertex, or polyhedral. [0013] In an aspect, embodiments of the invention feature a method of fabricating a metallic wire. One or more first metal powders and one or more second metal powders are combined to form at least a portion of a preform. Each of the first metal powders includes, consists essentially of, or consists of substantially spherical particles. Each of the second metal powders includes, consists essentially of, or consists of non-spherical particles. The one or more first metal powders are mixed with the one or more second metal particles such that a composition of the preform is substantially homogenous along at least a portion of the length of the preform. The diameter (or other lateral dimension such as a width) of the preform is reduced via one or more mechanical deformation processes to form a metallic wire. The metallic wire includes, consists essentially of, or consists of a high-entropy alloy that includes, consists essentially of, or consists of five or more metallic elements. Each first metal powder includes, consists essentially of, or consists of at least one of the metallic elements. Each second metal powder includes, consists essentially of, or consists of at least one of the metallic elements. [0014] Embodiments of the invention may include one or more of the following in any of a variety of combinations. The five or more metallic elements may include, consist essentially of, or consist of at least five of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders and/or at least one of the second metal powders, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. The one or more mechanical deformation processes may include, consist essentially of, or consist of drawing, pilgering, swaging, extrusion, and/or rolling. [0015] The preform may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The one or more first metal powders and the one or more second metal powders may be combined within one or more sacrificial tubes. One or more (or even all) of the sacrificial tubes may be removed before, during, and/or after the diameter (or other lateral dimension) of the preform is reduced. Removing one or more of the sacrificial tubes may include, consist essentially of, or consist of melting and/or etching (e.g., wet chemical (e.g., acid) etching and/or dry (e.g., plasma) etching). [0016] At least one of the first metal powders may be provided by a process including, consisting essentially of, or consisting of (a) providing a plurality of metal particulates and/or metal wire, (b) feeding the metal particulates and/or wire into a plasma, thereby at least partially melting (and/or atomizing and/or breaking apart) the metal particulates and/or wire, and (c) cooling the at least partially melted metal particulates and/or wire portions to form substantially spherical particles. At least one of the second metal powders may be provided by a process including, consisting essentially of, or consisting of (a) hydrogenating metal to form a metal hydride, (b) mechanically grinding the metal hydride into a plurality of non-spherical particles, and (c) dehydrogenating the non-spherical metal hydride particles. An average particle size of at least one of the first metal powders may range from approximately 15 μm to approximately 45 μm. An average particle size of at least one of the second metal powders may be greater than approximately 50 μm. An average particle size of at least one of the second metal powders may range from approximately 50 μm to approximately 100 μm or approximately 200 μm. An average particle size of one or more (or even all) of the first metal powders may be smaller than an average particle size of one or more (or even all) of the second metal powders. Embodiments of the invention may include wires formed by one or more of the above methods. [0017] The wire may be utilized in an additive manufacturing process to form a three-dimensional part in, e.g., layer-by-layer fashion. A tip of the wire may be translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). During the relative translation, the tip of the wire may be melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the five or more metallic elements. The bead may cool to form at least a portion of a layer of a three-dimensional part. These steps may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part may include, consist essentially of, or consist of the high-entropy alloy. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0018] In another aspect, embodiments of the invention feature a method of fabricating a metallic wire or wire preform that includes, consists essentially of, or consists of a high-entropy alloy including, consisting essentially of, or consisting of five or more metallic elements. A metallic tube is provided. The metallic tube includes, consists essentially of, or consists of at least one of the metallic elements of the high-entropy alloy. One or more first metal powders and one or more second metal powders are combined within the metallic tube. Each of the first metal powders includes, consists essentially of, or consists of substantially spherical particles. Each of the second metal powders includes, consists essentially of, or consists of non-spherical particles. The one or more first metal powders are mixed with the one or more second metal particles such that a composition of the combined powders is substantially homogenous along at least a portion of the length of the metallic tube, thereby forming the metallic wire or wire preform. Each first metal powder includes, consists essentially of, or consists of at least one of the metallic elements of the high-entropy alloy. Each second metal powder includes, consists essentially of, or consists of at least one of the metallic elements of the high-entropy alloy. [0019] Embodiments of the invention may include one or more of the following in any of a variety of combinations. The diameter (or other lateral dimension, e.g., width) of the metallic wire or wire preform may be reduced via one or more mechanical deformation processes. The one or more mechanical deformation processes may include, consist essentially of, or consist of drawing, pilgering, swaging, extrusion, and/or rolling. The five or more metallic elements may include, consist essentially of, or consist of at least five of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or of the metallic tube, and/or of the wire or wire preform itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. The metallic tube may include, consist essentially of, or consist of one of the metallic elements. The metallic tube may be an alloy tube including, consisting essentially of, or consisting of two or more of the metallic elements. [0020] At least one of the first metal powders may be provided by a process including, consisting essentially of, or consisting of (a) providing a plurality of metal particulates and/or metal wire, (b) feeding the metal particulates and/or wire into a plasma, thereby at least partially melting (and/or atomizing and/or breaking apart) the metal particulates and/or wire, and (c) cooling the at least partially melted metal particulates and/or wire portions to form substantially spherical particles. At least one of the second metal powders may be provided by a process including, consisting essentially of, or consisting of (a) hydrogenating metal to form a metal hydride, (b) mechanically grinding the metal hydride into a plurality of non-spherical particles, and (c) dehydrogenating the non-spherical metal hydride particles. An average particle size of at least one of the first metal powders may range from approximately 15 μm to approximately 45 μm. An average particle size of at least one of the second metal powders may be greater than approximately 50 μm. An average particle size of at least one of the second metal powders may range from approximately 50 μm to approximately 100 μm or approximately 200 μm. An average particle size of one or more (or even all) of the first metal powders may be smaller than an average particle size of one or more (or even all) of the second metal powders. Embodiments of the invention may include wires or wire preforms formed by one or more of the above methods. [0021] The wire may be utilized in an additive manufacturing process to form a three-dimensional part in, e.g., layer-by-layer fashion. A tip of the wire may be translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). During the relative translation, the tip of the wire may be melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the five or more metallic elements. The bead may cool to form at least a portion of a layer of a three-dimensional part. These steps may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part may include, consist essentially of, or consist of the high-entropy alloy. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0022] In yet another aspect, embodiments of the invention feature a method of forming a three-dimensional part including, consisting essentially of, or consisting of a high entropy alloy by additive manufacturing. The high entropy alloy includes, consists essentially of, or consists of five or more metallic elements selected from the group consisting of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and Cr. In a step (a), a wire is provided. The wire includes, consists essentially of, or consists of a substantially homogenous assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Particles of each first metal powder are substantially spherical. Particles of each second metal powder are non-spherical. In a step (b), a tip of the wire is translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). In a step (c), during the relative translation, the tip of the wire is melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the five or more metallic elements. The bead cools to form at least a portion of a layer of a three-dimensional part. Steps (b) and (c) may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part includes, consists essentially of, or consists of the high-entropy alloy. [0023] Embodiments of the invention may include one or more of the following in any of a variety of combinations. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The wire may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or at least one metallic tube, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0024] In another aspect, embodiments of the invention feature a high-entropy-alloy wire or wire preform including, consisting essentially of, or consisting of five or more metallic elements. The wire or wire preform includes, consists essentially of, or consists of an assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Particles of each first metal powder are substantially spherical. Particles of each second metal powder are non-spherical. [0025] Embodiments of the invention may include one or more of the following in any of a variety of combinations. The five or more metallic elements may include, consist essentially of, or consist of at least five of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The wire or wire preform may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or of the metallic tube, and/or of the wire or wire preform itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. [0026] In an aspect, embodiments of the invention feature a method of fabricating a metallic wire. One or more first metal powders and one or more second metal powders are combined to form at least a portion of a preform. Each of the first metal powders includes, consists essentially of, or consists of substantially spherical particles. Each of the second metal powders includes, consists essentially of, or consists of non-spherical particles. The one or more first metal powders are mixed with the one or more second metal particles such that a composition of the preform is substantially homogenous along at least a portion of the length of the preform. The diameter (or other lateral dimension such as a width) of the preform is reduced via one or more mechanical deformation processes to form a metallic wire. The metallic wire includes, consists essentially of, or consists of (1) a high-entropy alloy that includes, consists essentially of, or consists of five or more metallic elements or (2) a multi-principal element alloy that includes, consists essentially of, or consists of four or more metallic elements. Each first metal powder includes, consists essentially of, or consists of at least one of the metallic elements. Each second metal powder includes, consists essentially of, or consists of at least one of the metallic elements. [0027] Embodiments of the invention may include one or more of the following in any of a variety of combinations. The metallic elements may include, consist essentially of, or consist of at least four or at least five of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders and/or at least one of the second metal powders, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. The one or more mechanical deformation processes may include, consist essentially of, or consist of drawing, pilgering, swaging, extrusion, and/or rolling. [0028] The preform may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The one or more first metal powders and the one or more second metal powders may be combined within one or more sacrificial tubes. One or more (or even all) of the sacrificial tubes may be removed before, during, and/or after the diameter (or other lateral dimension) of the preform is reduced. Removing one or more of the sacrificial tubes may include, consist essentially of, or consist of melting and/or etching (e.g., wet chemical (e.g., acid) etching and/or dry (e.g., plasma) etching). [0029] At least one of the first metal powders may be provided by a process including, consisting essentially of, or consisting of (a) providing a plurality of metal particulates and/or metal wire, (b) feeding the metal particulates and/or wire into a plasma, thereby at least partially melting (and/or atomizing and/or breaking apart) the metal particulates and/or wire, and (c) cooling the at least partially melted metal particulates and/or wire portions to form substantially spherical particles. At least one of the second metal powders may be provided by a process including, consisting essentially of, or consisting of (a) hydrogenating metal to form a metal hydride, (b) mechanically grinding the metal hydride into a plurality of non-spherical particles, and (c) dehydrogenating the non-spherical metal hydride particles. An average particle size of at least one of the first metal powders may range from approximately 15 μm to approximately 45 μm. An average particle size of at least one of the second metal powders may be greater than approximately 50 μm. An average particle size of at least one of the second metal powders may range from approximately 50 μm to approximately 100 μm or approximately 200 μm. An average particle size of one or more (or even all) of the first metal powders may be smaller than an average particle size of one or more (or even all) of the second metal powders. Embodiments of the invention may include wires formed by one or more of the above methods. [0030] The wire may be utilized in an additive manufacturing process to form a three-dimensional part in, e.g., layer-by-layer fashion. A tip of the wire may be translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). During the relative translation, the tip of the wire may be melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the four or more metallic elements or the five or more metallic elements. The bead may cool to form at least a portion of a layer of a three-dimensional part. These steps may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part may include, consist essentially of, or consist of the high-entropy alloy or the multi-principal element alloy. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0031] In another aspect, embodiments of the invention feature a method of fabricating a metallic wire or wire preform that includes, consists essentially of, or consists of (1) a high-entropy alloy including, consisting essentially of, or consisting of five or more metallic elements or (2) a multi-principal element alloy including, consisting essentially of, or consisting of four or more metallic elements. A metallic tube is provided. The metallic tube includes, consists essentially of, or consists of at least one of the metallic elements of the high-entropy alloy or the multi-principal element alloy. One or more first metal powders and one or more second metal powders are combined within the metallic tube. Each of the first metal powders includes, consists essentially of, or consists of substantially spherical particles. Each of the second metal powders includes, consists essentially of, or consists of non-spherical particles. The one or more first metal powders are mixed with the one or more second metal particles such that a composition of the combined powders is substantially homogenous along at least a portion of the length of the metallic tube, thereby forming the metallic wire or wire preform. Each first metal powder includes, consists essentially of, or consists of at least one of the metallic elements of the high-entropy alloy or the multi-principal element alloy. Each second metal powder includes, consists essentially of, or consists of at least one of the metallic elements of the high-entropy alloy or the multi-principal element alloy. [0032] Embodiments of the invention may include one or more of the following in any of a variety of combinations. The diameter (or other lateral dimension, e.g., width) of the metallic wire or wire preform may be reduced via one or more mechanical deformation processes. The one or more mechanical deformation processes may include, consist essentially of, or consist of drawing, pilgering, swaging, extrusion, and/or rolling. The metallic elements may include, consist essentially of, or consist of at least four of or at least five of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or of the metallic tube, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. The metallic tube may include, consist essentially of, or consist of one of the metallic elements. The metallic tube may be an alloy tube including, consisting essentially of, or consisting of two or more of the metallic elements. [0033] At least one of the first metal powders may be provided by a process including, consisting essentially of, or consisting of (a) providing a plurality of metal particulates and/or metal wire, (b) feeding the metal particulates and/or wire into a plasma, thereby at least partially melting (and/or atomizing and/or breaking apart) the metal particulates and/or wire, and (c) cooling the at least partially melted metal particulates and/or wire portions to form substantially spherical particles. At least one of the second metal powders may be provided by a process including, consisting essentially of, or consisting of (a) hydrogenating metal to form a metal hydride, (b) mechanically grinding the metal hydride into a plurality of non-spherical particles, and (c) dehydrogenating the non-spherical metal hydride particles. An average particle size of at least one of the first metal powders may range from approximately 15 μm to approximately 45 μm. An average particle size of at least one of the second metal powders may be greater than approximately 50 μm. An average particle size of at least one of the second metal powders may range from approximately 50 μm to approximately 100 μm or approximately 200 μm. An average particle size of one or more (or even all) of the first metal powders may be smaller than an average particle size of one or more (or even all) of the second metal powders. Embodiments of the invention may include wires or wire preforms formed by one or more of the above methods. [0034] The wire may be utilized in an additive manufacturing process to form a three-dimensional part in, e.g., layer-by-layer fashion. A tip of the wire may be translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). During the relative translation, the tip of the wire may be melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the four or more metallic elements or the five or more metallic elements. The bead may cool to form at least a portion of a layer of a three-dimensional part. These steps may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part may include, consist essentially of, or consist of the high-entropy alloy or the multi-principal element alloy. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0035] In yet another aspect, embodiments of the invention feature a method of forming a three-dimensional part including, consisting essentially of, or consisting of a high-entropy alloy or a multi-principal element alloy by additive manufacturing. The high-entropy alloy includes, consists essentially of, or consists of five or more metallic elements selected from the group consisting of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and Cr. The multi-principal element alloy includes, consists essentially of, or consists of four or more metallic elements selected from the group consisting of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and Cr. In a step (a), a wire is provided. The wire includes, consists essentially of, or consists of a substantially homogenous assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Particles of each first metal powder are substantially spherical. Particles of each second metal powder are non-spherical. In a step (b), a tip of the wire is translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). In a step (c), during the relative translation, the tip of the wire is melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the four or more metallic elements or the five or more metallic elements. The bead cools to form at least a portion of a layer of a three-dimensional part. Steps (b) and (c) may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part includes, consists essentially of, or consists of the high-entropy alloy or the multi-principal element alloy. [0036] Embodiments of the invention may include one or more of the following in any of a variety of combinations. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The wire may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or at least one metallic tube, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0037] In another aspect, embodiments of the invention feature a multi-principal element alloy wire or wire preform including, consisting essentially of, or consisting of four or more metallic elements. The wire or wire preform includes, consists essentially of, or consists of an assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Particles of each first metal powder are substantially spherical. Particles of each second metal powder are non-spherical. [0038] Embodiments of the invention may include one or more of the following in any of a variety of combinations. The four or more metallic elements may include, consist essentially of, or consist of at least four of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The wire may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or of the metallic tube, and/or of the wire or wire preform itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. [0039] In yet another aspect, embodiments of the invention feature a method of forming a three-dimensional part including, consisting essentially of, or consisting of a high-entropy alloy or a multi-principal element alloy by additive manufacturing. The high-entropy alloy includes, consists essentially of, or consists of five or more metallic elements selected from the group consisting of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and Cr. The multi-principal element alloy includes, consists essentially of, or consists of four or more metallic elements selected from the group consisting of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and Cr. In a step (a), a wire preform is provided. The wire preform includes, consists essentially of, or consists of a substantially homogenous assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Particles of each first metal powder are substantially spherical. Particles of each second metal powder are non-spherical. In a step (b), a diameter (or other lateral dimension such as width) of the wire preform is reduced via one or more mechanical deformation processes, thereby forming a metallic wire. In a step (c), a tip of the wire is translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). In a step (d), during the relative translation, the tip of the wire is melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the four or more metallic elements or the five or more metallic elements. The bead cools to form at least a portion of a layer of a three-dimensional part. Steps (c) and (d) may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part includes, consists essentially of, or consists of the high-entropy alloy or the multi-principal element alloy. [0040] Embodiments of the invention may include one or more of the following in any of a variety of combinations. The one or more mechanical deformation processes may include, consist essentially of, or consist of drawing, pilgering, swaging, extrusion, and/or rolling. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least some of the non-spherical particles of at least one second metal powder may be angular flakes. The wire preform may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or at least one metallic tube, and/or of the wire preform, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less,or 10 ppm or less. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0041] In an aspect, embodiments of the invention feature a high-entropy-alloy wire including, consisting essentially of, or consisting of five or more metallic elements. The wire includes, consists essentially of, or consists of an assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. At least some particles of at least one first metal powder are substantially spherical. At least some particles of at least one second metal powder are elongated in the axial direction and extend at least partially around particles of the one or more first metal powders. [0042] Embodiments of the invention may include one or more of the following in any of a variety of combinations. At least some of the particles of each of the first metal powders may be substantially spherical. At least some particles of at least one first metal powder may be elongated in the axial direction. At least some particles of each of the first metal powders may be elongated in the axial direction. Particles of at least one first metal powder may be less ductile than particles of at least one second metal powder. Particles of all of the first metal powders may be less ductile than particles of all of the second metal powders. The one or more first metal powders may include, consist essentially of, or consist of Mo and/or W. The one or more second metal powders may include, consist essentially of, or consist of Ta and/or Nb. [0043] The five or more metallic elements may include, consist essentially of, or consist of at least five of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. The wire may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or of the metallic tube, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. [0044] In another aspect, embodiments of the invention feature a multi-principal element alloy wire or wire preform including, consisting essentially of, or consisting of four or more metallic elements. The wire includes, consists essentially of, or consists of an assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. At least some particles of at least one first metal powder are substantially spherical. At least some particles of at least one second metal powder are elongated in the axial direction and extend at least partially around particles of the one or more first metal powders. [0045] Embodiments of the invention may include one or more of the following in any of a variety of combinations. At least some of the particles of each of the first metal powders may be substantially spherical. At least some particles of at least one first metal powder may be elongated in the axial direction. At least some particles of each of the first metal powders may be elongated in the axial direction. Particles of at least one first metal powder may be less ductile than particles of at least one second metal powder. Particles of all of the first metal powders may be less ductile than particles of all of the second metal powders. The one or more first metal powders may include, consist essentially of, or consist of Mo and/or W. The one or more second metal powders may include, consist essentially of, or consist of Ta and/or Nb. [0046] The four or more metallic elements may include, consist essentially of, or consist of at least four of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and/or Cr. At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. The wire may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or of the metallic tube, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. [0047] In yet another aspect, embodiments of the invention feature a method of forming a three-dimensional part including, consisting essentially of, or consisting of a high-entropy alloy or a multi-principal element alloy by additive manufacturing. The high-entropy alloy includes, consists essentially of, or consists of five or more metallic elements selected from the group consisting of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and Cr. The multi-principal element alloy includes, consists essentially of, or consists of four or more metallic elements selected from the group consisting of Nb, Ta, Mo, W, Ti, Hf, V, Zr, Al, and Cr. In a step (a), a wire that extends in an axial direction is provided. The wire includes, consists essentially of, or consists of a substantially homogenous assemblage of one or more first metal powders and one or more second metal powders. Each first metal powder includes, consists essentially of, or consists of one or more of the metallic elements. Each second metal powder includes, consists essentially of, or consists of one or more of the metallic elements. At least some particles of at least one first metal powder are substantially spherical. At least some particles of at least one second metal powder are elongated in the axial direction and extend at least partially around particles of at least one of the first metal powders. In a step (b), a tip of the wire is translated relative to a platform (i.e., the wire may be translated, the platform may be translated, or both may be translated). In a step (c), during the relative translation, the tip of the wire is melted using an energy source to form a molten bead including, consisting essentially of, or consisting of the four or more metallic elements or the five or more metallic elements. The bead cools to form at least a portion of a layer of a three-dimensional part. Steps (b) and (c) may be repeated one or more times to produce at least a portion of the three-dimensional part. The three-dimensional part includes, consists essentially of, or consists of the high-entropy alloy or the multi-principal element alloy. [0048] Embodiments of the invention may include one or more of the following in any of a variety of combinations. At least some of the particles of each of the first metal powders may be substantially spherical. At least some particles of at least one first metal powder may be elongated in the axial direction. At least some particles of each of the first metal powders may be elongated in the axial direction. Particles of at least one first metal powder may be less ductile than particles of at least one second metal powder. Particles of all of the first metal powders may be less ductile than particles of all of the second metal powders. The one or more first metal powders may include, consist essentially of, or consist of Mo and/or W. The one or more second metal powders may include, consist essentially of, or consist of Ta and/or Nb. [0049] At least one first metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one first metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. At least one second metal powder may be an elemental powder including, consisting essentially of, or consisting of one of the metallic elements. At least one second metal powder may be an alloy powder including, consisting essentially of, or consisting of two or more of the metallic elements. The wire may include one or more metallic tubes surrounding the one or more first metal powders and the one or more second metal powders. Each metallic tube may include, consist essentially of, or consist of at least one of the metallic elements. The concentration of oxygen, carbon, calcium, sodium, antimony, phosphorus, sulfur, and/or nitrogen of at least one of the first metal powders, and/or at least one of the second metal powders, and/or at least one metallic tube, and/or of the wire itself, may be 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less. Embodiments of the invention may include three-dimensional parts formed according to any of the above methods. [0050] These and other objects, along with advantages and features of the present invention herein disclosed, will become more 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 may exist in various combinations and permutations. As used herein, the terms “approximately” and “substantially” mean ±10%, and in some embodiments, ±5%. The term “consists essentially of” means excluding other materials that contribute to function, unless otherwise defined herein. Nonetheless, such other materials may be present, collectively or individually, in trace amounts. For example, a structure consisting essentially of multiple metals will generally include only those metals and only unintentional impurities (which may be metallic or non-metallic) that may be detectable via chemical analysis but do not contribute to function. As used herein, “consisting essentially of at least one metal” refers to a metal or a mixture of two or more metals but not compounds between a metal and a non-metallic element or chemical species such as oxygen, silicon, or nitrogen (e.g., metal nitrides, metal silicides, or metal oxides); such non-metallic elements or chemical species may be present, collectively or individually, in trace amounts, e.g., as impurities. BRIEF DESCRIPTION OF THE DRAWINGS [0051] 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: [0052] FIG. 1 is a schematic cross-sectional view of a plasma densification apparatus utilized to form spherical powder particles in accordance with various embodiments of the invention; [0053] FIG. 2A is a schematic cross-section of a wire preform in accordance with various embodiments of the invention; [0054] FIG. 2B is a schematic view of a wire being fabricated from a wire preform in accordance with various embodiments of the invention; [0055] FIG. 2C is a schematic cross-section of a wire preform containing multiple coaxial tubes in accordance with various embodiments of the invention; [0056] FIG. 3 is a schematic of an additive-manufacturing apparatus utilized to fabricate three-dimensional metallic parts in accordance with various embodiments of the invention; [0057] FIG. 4A is an axial cross-section of a wire fabricated in accordance with various embodiments of the invention; [0058] FIG. 4B is a longitudinal cross-section of the wire of FIG. 4A ; [0059] FIG. 5 is a cross-sectional micrograph of a melted and resolidified multi-principal element alloy wire fabricated in accordance with various embodiments of the invention; and [0060] FIGS. 6 and 7 are cross-sectional micrographs of a melted and resolidified high-entropy alloy fabricated in accordance with various embodiments of the invention. DETAILED DESCRIPTION [0061] In various embodiments of the present invention, a preform in the shape of, e.g., a rod or a bar, is provided by pressing and/or sintering a collection of powders. Collectively, the powders contain all of the elements of a desired HEA or MPEA. For example, one or more, or even all, of the powders may each be composed of particles that include, consist essentially of, or consist of one of the alloy's constituent elements. In other embodiments, one or more of the powders may each be composed of agglomerate particles including, consisting essentially of, or consisting of a mixture or alloy of two or more of the alloy's constituent elements. [0062] In accordance with various embodiments of the invention, the preform contains one or more powders composed of substantially spherical particles and one or more powders composed of non-spherical (e.g., flaky, angular, irregular, etc.) particles. For example, powder particles of tungsten and/or molybdenum (e.g., particles initially fabricated via a hydride/dehydride process or other process) may be plasma densified and may therefore be substantially spherical. An exemplary apparatus 100 for plasma densification is shown schematically in FIG. 1 . As shown, powder particles 110 may be loaded into a powder feeder 120 , which feeds the particles 110 through a plasma jet 130 formed by, for example, a time-varying current applied to an induction coil 140 sparking a plasma 150 from plasma gas 160 fed into the coil 140 . The plasma jet 130 at least partially melts the particles 110 , which subsequently resolidify into higher-density particles 170 collected below the plasma 150 . The plasma-densified particles 170 are generally substantially spherical due to the plasma-induced melting and minimization of surface area resulting during resolidification. The minimization of the surface area of the particles also minimizes or substantially reduces the uptake of oxygen or other volatile species, and the plasma densification process itself volatilizes such species as well, thereby reducing the concentration of such contaminants within the powder 170 . The plasma-densified powder particles 170 may have an average particle size of, for example, 15 μm to 45 μm, or even smaller. [0063] FIG. 2A depicts the fabrication of a wire preform 200 in accordance with embodiments of the present invention. One or more types of substantially spherical powder particles 170 are mixed with one or more powders of non-spherical particles 210 (e.g., within a tube 220 or in a cylindrical mold) such that all of the elements of the desired alloy are included within the preform 200 . The non-spherical powder particles 210 may be formed by, e.g., a hydride/dehydride process. In various embodiments of the invention, the non-spherical powder particles are not rounded, oblong, ellipsoidal, and/or do not have smooth rounded surfaces along any portion of their surface areas. The non-spherical powder particles 210 may have an average particle size of, for example, less than or equal to 50 μm to 250 μm, or even larger. As mentioned above, either or both of the substantially spherical particles 170 or the non-spherical powder particles 210 may be individually composed of an alloy or mixture of two or more of the elements of the desired alloy. Such alloy powders may be formed via, e.g., hydride/dehydride of pre-alloyed ingots and optional plasma densification of powders resulting therefrom. [0064] In various embodiments, the melting point of one or more of the types of substantially spherical particles 170 is higher than the melting point of one or more of the types of non-spherical particles 210 . In various embodiments, the ductility of one or more of the types of substantially spherical particles 170 is lower than the ductility of one or more of the types of non-spherical particles 210 . In various embodiments, none of the metallic elements within the substantially spherical particles 170 are present within the non-spherical particles 210 and vice versa. In various embodiments, one or more of the metallic elements of the desired HEA are represented in both the substantially spherical particles 170 and the non-spherical particles 210 . In some embodiments, both the substantially spherical particles 170 and the non-spherical particles 210 contain all of the metallic elements of the desired alloy, as elemental powder particles and/or alloy powder particles. [0065] The resulting mixture of substantially spherical particles 170 and non-spherical powder particles 210 within the preform 200 advantageously reduces or minimizes the amount of empty void space within the preform 200 . The particles 170 , 210 are preferably distributed within the preform 200 such that the composition of the preform 200 is substantially homogeneous along its length. In various embodiments, the preform 200 and/or at least a portion of the powder mixture therein may be further densified before further processing into wire. For example, the preform 200 and/or the powder mixture may be pressed by, e.g., hot isostatic pressing or cold isostatic pressing. The powder or the preform may be densified before and/or after inclusion of a sacrificial tube (as detailed below). After formation of the preform 200 , the preform 200 is processed into a wire 230 . In an exemplary embodiment depicted in FIG. 2B , the preform 200 is formed into wire 230 via drawing through one or more drawing dies 240 until the diameter of the wire 230 is reduced to the desired dimension. In various embodiments, various types of the particles of the preform 200 , particularly those having relatively low ductility (e.g., molybdenum, tungsten, etc.) may have their morphologies deform during the processing of the preform 200 into wire 230 . For example, substantially spherical particles 170 of molybdenum and/or tungsten may be elongated into oblong shapes or ribbons (e.g., along the wire axis), and/or they may remain substantially spherical in the final wire 230 . Other types of particles having higher ductility (e.g., tantalum, niobium, etc.) may elongate around the other particles and form a matrix disposed around the harder particles in the final wire. In various embodiments, the drawing is supplemented with or replaced by one or more other mechanical deformation processes that reduce the diameter (or other lateral dimension) of the preform 200 , e.g., pilgering, rolling, swaging, extrusion, etc. The preform 200 and/or wire 230 may be annealed during and/or after diameter reduction (e.g., drawing). [0066] In various embodiments, the preform 200 is formed via the combination of one or more substantially spherical powders 170 with one or more non-spherical powders 210 within a tube 220 that includes, consists essentially of, or consists of one or more of the elements of the desired HEA or MPEA. The tube 220 may itself be coaxially disposed within one or more other tubes 250 that include, consist essentially of, or consist of one or more other elements of the HEA, as shown in FIG. 2C . In such embodiments, the powders disposed within the tubes need not include the elements represented within the tube(s). When the preform 200 containing the one or more tubes is drawn down into wire 230 , the cross-section of the wire 230 will thus include all of the elemental constituents of the desired alloy. In various embodiments, at least a portion of the powder mixture may be further densified before being placed into tube 220 . For example, the powder mixture may be pressed by, e.g., hot isostatic pressing or cold isostatic pressing. [0067] In various embodiments, the one or more tubes may include, consist essentially of, or consist of one or more elements that are more ductile than one or more of the elements present in powder form. For example, the one or more tubes may include, consist essentially of, or consist of Nb, Ta, Ti, and/or Zr. In various embodiments, the one or more tubes have a sufficiently small diameter that the preform 200 itself may be utilized as the final wire 230 without further processing or diameter reduction such as wire drawing. In various embodiments, the one or more tubes, with the powders therewithin, may be annealed and/or subjected to pressure (e.g., hot-isostatically pressed) before (or between multiple steps of) the process of diameter reduction. Such treatment may advantageously reduce void space within and increase the density of the final wire 230 . [0068] In various embodiments, the melting point of one or more of the types of substantially spherical particles 170 and/or one or more of the types of non-spherical particles 210 is higher than the melting point of one or more of the metallic elements of one or more of the tubes 220 , 250 . In various embodiments, the ductility of one or more of the types of substantially spherical particles 170 and/or one or more of the types of non-spherical particles 210 is lower than the ductility of one or more of the metallic elements of one or more of the tubes 220 , 250 . In various embodiments, none of the metallic elements within the substantially spherical particles 170 and/or the non-spherical particles 210 are present within the tubes 220 , 250 and vice versa. In various embodiments, one or more of the metallic elements of the desired alloy are represented in at least one of the types of substantially spherical particles 170 and/or at least one of the types of non-spherical particles 210 , as well as in one or more of the tubes 220 , 250 . [0069] In other embodiments, the preform 200 may include, consist essentially of, or consist of a sacrificial tube 220 in which the various powders 170 , 210 are disposed. After processing of the preform 200 into wire 230 , the sacrificial tube 220 may be etched or melted away, and the final wire 230 includes, consists essentially of, or consists of the elements of the desired alloy arising solely from the original powders 170 , 210 . In various embodiments, one or more tubes to be processed as part of the wire may be disposed within the sacrificial tube 220 ; at least portions of such tubes will typically remain as portions of the wire after removal of the sacrificial tube 220 . The sacrificial tube 220 may include, consist essentially of, or consist of, for example, plastic, rubber, one or more polymeric materials, a metallic material having a melting point lower than one or more (or even all) of the metallic elements within the powders 170 , 210 , a metallic material selectively etchable (i.e., over the metallic elements within the powders 170 , 210 and other tubes), etc. [0070] Once wire 230 including, consisting essentially of, or consisting of the elemental constituents of a desired HEA or MPEA is fabricated in accordance with embodiments of the invention, the wire 230 may be utilized to fabricate a three-dimensional part with an additive manufacturing assembly 300 . For example, as shown in FIG. 3 , the wire 230 may be incrementally fed, using a wire feeder 310 , into the path of a high-energy source 320 (e.g., an electron beam or a laser beam emitted by a laser or electron-beam source 330 ), which melts the tip of the wire 230 to form a small molten pool (or “bead” or “puddle”) 340 . The entire assembly 300 may be disposed within a vacuum chamber to prevent or substantially reduce contamination from the ambient environment. [0071] Relative movement between a substrate 350 (which may be, as shown, disposed on a platform 360 ) supporting the deposit and the wire/gun assembly results in the part being fabricated in a layer-by-layer fashion. Such relative motion results in the continuous formation of a layer 370 of the three-dimensional object from continuous formation of molten pool 340 at the tip of the wire 230 . As shown in FIG. 3 , all or a portion of layer 370 may be formed over one or more previously formed layers 380 . The relative movement (i.e., movement of the platform 360 , the wire/gun assembly, or both) may be controlled by a computer-based controller 380 based on electronically stored representations of the part to be fabricated. For example, the two-dimensional layers traced out by the melting wire may be extracted from a stored three-dimensional representation of the final part stored in a memory 390 . [0072] The computer-based control system (or “controller”) 380 in accordance with embodiments of the present invention may include or consist essentially of a general-purpose computing device in the form of a computer including a processing unit (or “computer processor”) 392 , the system memory 390 , and a system bus 394 that couples various system components including the system memory 390 to the processing unit 392 . Computers typically include a variety of computer-readable media that can form part of the system memory 390 and be read by the processing unit 392 . By way of example, and not limitation, computer readable media may include computer storage media and/or communication media. The system memory 390 may include computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) and random access memory (RAM). A basic input/output system (BIOS), containing the basic routines that help to transfer information between elements, such as during start-up, is typically stored in ROM. RAM typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 392 . The data or program modules may include an operating system, application programs, other program modules, and program data. The operating system may be or include a variety of operating systems such as Microsoft WINDOWS operating system, the Unix operating system, the Linux operating system, the Xenix operating system, the IBM AIX operating system, the Hewlett Packard UX operating system, the Novell NETWARE operating system, the Sun Microsystems SOLARIS operating system, the OS/2 operating system, the BeOS operating system, the MACINTOSH operating system, the APACHE operating system, an OPENSTEP operating system or another operating system of platform. [0073] Any suitable programming language may be used to implement without undue experimentation the functions described herein. Illustratively, the programming language used may include assembly language, Ada, APL, Basic, C, C++, C*, COBOL, dBase, Forth, FORTRAN, Java, Modula-2, Pascal, Prolog, Python, REXX, and/or JavaScript for example. Further, it is not necessary that a single type of instruction or programming language be utilized in conjunction with the operation of systems and techniques of the invention. Rather, any number of different programming languages may be utilized as is necessary or desirable. [0074] The computing environment may also include other removable/nonremovable, volatile/nonvolatile computer storage media. For example, a hard disk drive may read or write to nonremovable, nonvolatile magnetic media. A magnetic disk drive may read from or writes to a removable, nonvolatile magnetic disk, and an optical disk drive may read from or write to a removable, nonvolatile optical disk such as a CD-ROM or other optical media. Other removable/nonremovable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The storage media are typically connected to the system bus through a removable or non-removable memory interface. [0075] The processing unit 392 that executes commands and instructions may be a general-purpose computer processor, but may utilize any of a wide variety of other technologies including special-purpose hardware, a microcomputer, mini-computer, mainframe computer, programmed micro-processor, micro-controller, peripheral integrated circuit element, a CSIC (Customer Specific Integrated Circuit), ASIC (Application Specific Integrated Circuit), a logic circuit, a digital signal processor, a programmable logic device such as an FPGA (Field Programmable Gate Array), PLD (Programmable Logic Device), PLA (Programmable Logic Array), RFID processor, smart chip, or any other device or arrangement of devices that is capable of implementing the steps of the processes of embodiments of the invention. [0076] Advantageously, wires in accordance with embodiments of the invention are substantially homogeneous in composition. Thus, all of the elements of the desired HEA or MPEA are present in each small molten pool 340 of material at any particular instant during fabrication. Due to their small size, the pools 340 cool quickly, locking in the desired alloy composition. In addition, since empty void space within the wire 230 fabricated in accordance with embodiments of the present invention was substantially eliminated via packing of powder particles with multiple different shapes and/or sizes, the wire 230 melts during additive manufacturing with little if any sparking and without introducing porosity, cracks, or other defects into the printed part. After the additive manufacturing process is complete, the part may be removed from the platform and subjected to final machining and/or polishing. EXAMPLE [0077] A substantially pure Cu tube having a 0.648 inch outer diameter and a 0.524 inch inner diameter was wrapped around a Ta-3W (i.e., Ta—W alloy containing approximately 3% W) welded tube having an outer diameter of 0.500 inch and an inner diameter of 0.470 inch. A powder blend of 4 weight percent Ta non-spherical powder particles, 32 weight percent Nb non-spherical powder particles, 32 weight percent Mo substantially spherical powder particles, and 32 weight percent W substantially spherical powder particles was utilized to fill the Ta-3W tube at an apparent fill density of approximately 51%. The Ta and Nb powder particles were low-oxygen powder particles formed by a hydride-dehydride process and thus had the form of angular flakes. The Mo and W powder particles were formed via a plasma densification process. Taking into account the Ta-3W tube, the preform within the Cu tube contained 24.3 atomic percent Ta, 25.7 atomic percent W, 25.0 atomic percent Mo, and 25.0 atomic percent Nb. In total, 390 grams of powder were utilized. [0078] The ends of the Cu tube were sealed with Cu plugs, and the assembly was cold swaged to 0.069 inch diameter in about 20 steps ranging from 5% to 25% area reduction per pass, depending upon the available swage diameter for each pass. To minimize powder slip within the tube, the rod was swaged along one-half of its length, flipped, and then swaged from the opposite end until the whole assembly had a substantially uniform diameter. Including the Cu tube and plugs, the starting weight was about 935 grams, and the assembly produced more than 600 linear inches of wire (approximately 100:1 total area reduction). FIGS. 4A and 4B are, respectively, axial and longitudinal cross-sectional micrographs of the wire at a diameter of 0.084 inch. As shown, some of the initially substantially spherical powder particles remain substantially spherical, while others have elongated along the long axis of the wire due to the mechanical deformation. In general, the softer Ta and Nb powder particles have elongated around the harder Mo and W powder particles. [0079] The Cu-sheathed wire was continuous and could be coiled to a diameter of 13 inches without breaking. The Cu sheath was removed prior to testing. For testing, lengths of the wire each having a length of 3 inches were cut and acid etched in a mixture of 25% nitric acid and 75% distilled water until all of the Cu was removed. In order to simulate the high-speed melting and resolidification of an additive manufacturing process, wire sections totaling 32 grams in weight were placed in a cold Cu hearth, and an electric arc from a W electrode supplied sufficient energy to melt the wire. The Cu hearth rapidly cooled the metal, thereby closely approximating the high rate of cooling in additive manufacturing. A second set of samples included sufficient pure V added to the hearth to produce a 20%-20%-20%-20%-20% (atomic percent) HEA of V—Nb—Ta—Mo—W. This second set of samples could also have been produced via inclusion of the proper amount of substantially spherical or non-spherical V powder particles within the starting Ta-3W tube. All of the samples produced in accordance with this example melted readily into a substantially homogenous mixture of their constituent elements and resolidified as a single solid solution phase. Moreover, all of the samples melted very gently and quietly (i.e., with minimal or no splattering, spitting, etc.), despite their origins as powder blends; thus, embodiments of the present invention have sufficiently high density and sufficiently low concentrations of volatile contaminants to ensure compatibility with additive manufacturing, welding, and other rapid melting and solidification processes. [0080] Scanning electron microscopy (SEM) energy dispersive X-ray spectrometry (EDS) was performed on one of the second set of samples, and the average composition of the five-element HEA was (22.6%-26.1%) W, (18.8%-20.6%) Ta, (18.8%-19.3%) Mo, (14.8%-16.0%) Nb, and (19.7%-23.3%) V, where all compositions are atomic percentages. Via SEM analysis, the samples were determined to be single-phase with the expected dendritic microstructure, and the inter-dendrite spacing ranged from approximately 10 μm to approximately 20 μm. FIG. 5 is a cross-sectional micrograph of one of the first set of samples after melting and resolidification. The sample was chemically etched to reveal the internal structure. As shown, some grain structure is visible with internal dendritic structure. The sample was swab-etched (as opposed to being fully immersed) with an etchant prepared from 5 ml lactic acid, 5 ml hydrogen peroxide, 2 ml hydrofluoric acid, and 2 ml nitric acid. FIGS. 6 and 7 are cross-sectional micrographs of one of the second set of samples after melting and resolidification. The sample in FIG. 6 was also chemically etched (with the same etchant detailed above with reference to FIG. 5 ) to reveal the internal structure, and the sample in FIG. 7 was polished but not chemically etched. The dendritic microstructure of the sample is quite evident. [0081] Finally, multiple Vickers hardness tests using a 1 kg load were performed on the first and second sets of samples, and the results obtained are included in the table below. [0000] Hardness Hardness Hardness Composition (Test 1) (Test 2) (Test 3) Nb—Ta—Mo—W 490 533 524 V—Nb—Ta—Mo—W 561 579 591 As expected, the second set of samples exhibits larger hardness values due to the addition of V into the alloy. The hardness values for both sets of samples are fairly high and imply high tensile strength of wires fabricated in accordance with embodiments of the present invention. [0082] The terms and expressions employed herein are used as terms and expressions of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof. In addition, having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive.

In various embodiments, metallic wires are fabricated by combining one or more powders of substantially spherical metal particles with one or more powders of non-spherical particles within one or more optional metallic tubes. The metal elements within the powders (and the one or more tubes, if present) collectively define a high entropy alloy of five or more metallic elements or a multi-principal element alloy of four or more metallic elements.

[0001] This application claims priority from U.S. provisional application Serial No. 60/189,704, filed Mar. 15, 2000. FIELD OF THE INVENTION [0002] The present invention relates to an improved process for preparing 4-substituted resorcinol derivatives. BACKGROUND OF THE INVENTION [0003] Resorcinol derivatives are known to be useful for a variety of purposes. For example, in the cosmetic field, resorcinol derivatives have been used as skin lightening agents. The use of resorcinol derivatives as skin lightening agents is described in European Patent Application EP 904,774, published Mar. 31, 1999; U.S. Pat. No. 5,468,472, issued Nov. 21, 1995; U.S. Pat. No. 5,399,785, issued Mar. 21, 1995; European Patent Application EP 623,339, published Nov. 9, 1994; JP 54905, published Jan. 14, 1993; and European Patent Application EP 341,664, published Nov. 15, 1989. [0004] Resorcinol derivatives have also been used as dandruff control agents (JP 4-169516, published Jun. 17, 1992); as anti-acne agents (JP 4-169511, published Jun. 17, 1992); as potentiators of anti-microbial compounds (U.S. Pat. No. 4,474,748, issued Oct. 2, 1984); as anti-browning agents for foods (U.S. Pat. No. 5,304,679, issued Apr. 19, 1994); and in the preparation of photographic dye images (U.S. Pat. No. 3,756, 818, issued Sep. 4, 1973). [0005] The present invention provides an improved process for preparing 4-substituted resorcinol derivatives. The present invention further provides intermediate compounds useful in preparing such resorcinol derivatives, as well as processes for preparing the intermediate compounds. The improved process of the present invention is easier to use than standard methods for preparing resorcinol derivatives in large quantities. In addition, the improved process of the present invention results in a higher yield of final product than standard methods. SUMMARY OF INVENTION [0006] The invention provides a process for preparing a resorcinol derivative of formula I: [0007] or a pharmaceutically acceptable salt thereof, wherein the dashed line indicates an optional double bond at that position, and wherein X and Y are each independently selected from hydrogen, (C 1 -C 12 )alkyl, (C 2 -C 12 )alkenyl, (C 2 -C 12 )alkynyl, or X and Y are taken together with the carbon to which they are attached to form a (C 4 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring, provided that the (C 4 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is not aromatic; which (C 1 -C 12 )alkyl, (C 2 -C 12 )alkenyl, (C 2 -C 12 )alkynyl, (C 4 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is optionally substituted by one to three independently selected groups Z, wherein Z is any substituent capable of being substituted thereon where the process of the present invention can be used to prepare the particular substituted resorcinol derivative. [0008] In a preferred embodiment, Z is selected from the group consisting of cyano; halo; (C 1 -C 6 )alkyl; aryl; (C 2 -C 9 )heterocycloalkyl; (C 2 -C 9 )heteroaryl; aryl(C 1 -C 6 )alkyl-; ═O; ═CHO(C 1 -C 6 )alkyl; amino; hydroxy; (C 1 -C 6 )alkoxy; aryl(C 1 -C 6 )alkoxy-; (C 1 -C 6 )acyl; (C 1 -C 6 )alkylamino-; aryl(C 1 -C 6 )alkylamino-; amino(C 1 -C 6 )alkyl-; (C 1 -C 6 )alkoxy-CO—NH—; (C 1 -C 6 )alkylamino-CO—; (C 2 -C 6 )alkenyl; (C 2 -C 6 )alkynyl; hydroxy(C 1 -C 6 )alkyl-; (C 1 -C 6 )alkoxy(C 1 -C 6 )alkyl-; (C 1 -C 6 )acyloxy(C 1 -C 6 )alkyl-; nitro; cyano(C 1 -C 6 )alkyl-; halo(C 1 -C 6 )alkyl-; nitro(C 1 -C 6 )alkyl-; trifluoromethyl; trifluoromethyl(C 1 -C 6 )alkyl-; (C 1 -C 6 )acylamino-; (C 1 -C 6 )acylamino(C 1 -C 6 )alkyl-; (C 1 -C 6 )alkoxy(C 1 -C 6 )acylamino-; amino(C 1 -C 6 )acyl-; amino(C 1 -C 6 )acyl(C 1 -C 6 )alkyl-; (C 1 -C 6 )alkylamino(C 1 -C 6 )acyl-; ((C 1 -C 6 )alkyl) 2 amino(C 1 -C 6 )acyl-; —CO 2 R 2 ; —(C 1 -C 6 )alkyl-CO 2 R 2 ; —C(O)N(R 2 ) 2 ; —(C 1 -C 6 )alkyl-C(O)N(R 2 ) 2 ; R 2 ON═; R 2 ON═(C 1 -C 6 )alkyl-; R 2 ON═CR 2 (C 1 C 6 )alkyl-; —NR 2 (OR 2 ); —(C 1 -C 6 )alkyl-NR 2 (OR 2 ), —C(O)(NR 2 OR 2 ); —(C 1 -C 6 )alkyl-C(O)(NR 2 OR 2 ); —S(O) m R 2 ; wherein each R 2 is independently selected from hydrogen, (C 1 -C 6 )alkyl, aryl, or aryl(C 1 -C 6 )alkyl-; R 3 C(O)O—, wherein R 3 is (C 1 -C 6 )alkyl, aryl, or aryl(C 1 -C 6 )alkyl-; R 3 C(O)O—(C 1 -C 6 )alkyl-; R 4 R 5 N—C(O)—O—; R 4 R 5 NS(O) 2 —; R 4 R 5 NS(O) 2 (C 1 -C 6 )alkyl-; R 4 S(O) 2 R 5 N—; R 4 S(O) 2 R 5 N(C 1 -C 6 )alkyl-; wherein m is 0, 1 or 2, and R 4 and R 5 are each independently selected from hydrogen or (C 1 -C 6 )alkyl; —C(═NR 6 )(N(R 4 ) 2 ); —(C 1 -C 6 )alkyl-C(═NR 6 )(N(R 4 ) 2 ) wherein R 6 represents OR 2 or R 2 wherein R 2 is defined as above; —OC(O)aryl(C 1 -C 6 )alkyl; —NH(C 1 -C 6 )alkyl; aryl(C 1 -C 6 )alkyl-HN—; and a ketal. [0009] The present invention also provides various intermediate compounds useful in this process, and methods for making them. Specifically, this invention relates to a process for preparing a compound of formula (6) [0010] wherein W is hydrogen or a protecting group; [0011] wherein X and Y are each independently selected from hydrogen, (C 1 -C 12 )alkyl, (C 2 -C 12 )alkenyl, (C 2 -C 12 )alkynyl, or X and Y are taken together with the carbon to which they are attached to form a (C 4 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring, provided that the (C 4 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is not aromatic; and wherein the (C 1 -C 12 )alkyl, (C 2 -C 12 )alkenyl, (C 2 -C 12 )alkynyl, (C 4 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is optionally further substituted by one to three independently selected groups Z, where Z is as defined above; [0012] comprising reacting a compound of formula (5) [0013] wherein Q is halo, with a base to form the compound of formula (6). In a preferred embodiment, Q is bromo, iodo or chloro; more preferably Q is bromo or iodo; and most preferably Q is bromo. [0014] The present invention further provides a process for preparing a compound of formula (7) [0015] wherein W, X and Y are as defined above; [0016] comprising reacting a compound of formula (5) [0017] wherein Q is as defined above, with a base to form the compound of formula (7). [0018] In a preferred embodiment, the compound of formula (5) is prepared by reacting the compound of formula (4) [0019] wherein W, X and Y are as defined above, with a halogenating agent, wherein the halogen corresponds to Q in the compound of formula (5). In a preferred embodiment, Q is bromo, and the compound of formula (5) is prepared by reacting the compound of formula (4) with a brominating agent such as, e.g., N-bromosuccinimide. [0020] In a further preferred embodiment, the compound of formula (4) is prepared by reacting a compound of formula (2) [0021] with a compound of formula (3) [0022] wherein W, X and Y are as defined above, in the presence of a base to form the compound of formula (4). [0023] The present invention further provides a process for preparing a compound of formula (5) [0024] wherein Q, W, X and Y are as defined above, comprising reacting the compound of formula (4) [0025] with a halogenating agent, as described above, to form the compound of formula (5). [0026] In a preferred embodiment, the compound of formula (4) is prepared by reacting a compound of formula (2) [0027] with a compound of formula (3) [0028] wherein W, X and Y are as defined above, in the presence of a base to form the compound of formula (4). [0029] The present invention further provides a process for preparing a compound of formula (4) [0030] wherein W, X and Y are as defined above; [0031] comprising reacting a compound of formula (2) [0032] with a compound of formula (3) [0033] in the presence of a base to form the compound of formula (4). [0034] The present invention further provides a process for preparing a compound of formula I(a) [0035] wherein X and Y are defined as above, comprising: [0036] (a) reacting a compound of formula (5) [0037]  wherein Q is halo, W is hydrogen or a protecting group, and X and Y are as defined above, with a base to form a compound of formula (6); and [0038] (b) where W is H, reducing the compound of formula (6) so formed to form the compound of formula I(a); or [0039] (c) where W is a protecting group, reducing the compound of formula (6) so formed and removing the protecting group to form the compound of formula I(a). [0040] In a preferred embodiment, the compound of formula (6) is reduced to form the compound of formula I(a) by reaction with triethysilane in the presence of a Lewis acid, or alternatively by hydrogenation under standard conditions. [0041] The present invention further provides a process for preparing a compound of formula I(a) [0042] wherein X and Y are as defined above; comprising: [0043] (a) reacting a compound of formula (5) [0044]  wherein Q is halo, W is hydrogen or a protecting group, and X and Y are as defined above, with a base to form a compound of formula (7); and [0045] (b) where W is H, hydrogenating the compound of formula (7) so formed to form the compound of formula I(a); or [0046] (c) where W is a protecting group, hydrogenating the compound of formula (7) so formed and removing the protecting group to form the compound of formula I(a). [0047] The present invention further provides a process for preparing a compound of formula I(a) [0048] wherein X and Y are defined as above; comprising: [0049] (a) reacting a compound of formula (5) [0050]  wherein Q is halo, W is hydrogen or a protecting group, and X and Y are as defined above, with a base to form a compound of formula (6); [0051] (b) reacting the compound of formula (6) so formed with a base to form a compound of formula (7); and [0052] (c) where W is H, hydrogenating the compound of formula (7) so formed to form the compound of formula I(a); or [0053] (d) where W is a protecting group, hydrogenating the compound of formula (7) so formed and removing the protecting group to form the compound of formula I(a). [0054] The present invention further provides a process for preparing a compound of formula I(a) [0055] wherein X and Y are as defined above; comprising: [0056] (a) reacting a compound of formula (5) [0057]  wherein Q is halo, W is hydrogen or a protecting group, and X and Y are as defined above, with a base to form a compound of formula (6); [0058] (b) reacting the compound of formula (6) so formed with a base to form a compound of formula (7); and [0059] (c) where W is H, hydrogenating the compound of formula (7) so formed to form the compound of formula I(a); or [0060] d) where W is a protecting group, removing the protecting group from compound (7) so formed to form the compound of formula I(b) [0061] and hydrogenating the compound of formula I(b) so formed to form the compound of formula I(a). [0062] The present invention further provides a process for preparing a compound of formula I(a) [0063] wherein X and Y are as defined above; comprising: [0064] (a) reacting a compound of formula (5) [0065]  wherein Q is halo, W is hydrogen or a protecting group, and X and Y are as defined above, with a base to form a compound of formula (7); and [0066] (b) where W is H, hydrogenating the compound of formula (7) so formed to form the compound of formula I(a); or [0067] (c) where W is a protecting group, removing the protecting group from compound (7) so formed to form the compound of formula I(b) [0068] and hydrogenating the compound of formula I(b) so formed to form the compound of formula I(a). [0069] The present invention further comprises a process for preparing a compound of formula I(b) [0070] wherein X and Y are as defined above; comprising: [0071] (a) reacting a compound of formula (5) [0072]  wherein Q is halo, W is hydrogen or a protecting group, and X and Y are as defined above, with a base to form a compound of formula (6); [0073] (b) reacting the compound of formula (6) so formed with a base to form a compound of formula I(b) when W is H, and a compound of formula (7) when W is a protecting group; and [0074] (c) when W is a protecting group, removing the protecting group from the compound of formula (7) so formed to form the compound of formula I(b). [0075] The present invention further provides a process for preparing a compound of formula I(b) [0076] wherein X and Y are defined as above; comprising: [0077] (a) reacting a compound of formula (5) [0078]  wherein Q is halo, W is hydrogen or a protecting group, and X and Y are as defined above, with a base to form a compound of formula I(b) when W is H, and a compound of formula (7) when W is a protecting group; and [0079] (b) when W is a protecting group, removing the protecting group from the compound of formula (7) so formed to form the compound of formula I(b). [0080] As explained below in the description of Scheme I, where W is H, the compound of formula (5) can exist in equilibrium with the compound of formula (5′) as follows. [0081] where W is H, the compound of formula (5′) may be formed directly from the compound of formula (4). In all of the processes described herein where W is H, where the compound of claim (5) is utilized, the compound of claim (5′) can be utilized in its place under the same reaction conditions as recited, e.g., to prepare the compounds of formula (6) or (7). The present invention also provides a process for preparing the compound of formula (5′) by treating the compound of formula (4), where W is H, with a halogenating agent to form the compound of formula (5′). [0082] The various processes of the present invention, as described above, are incorporated into Scheme 1, shown below. [0083] In a preferred non-limiting embodiment, X and Y are taken together with the carbon to which they are attached to form a (C 5 -C 8 )cycloalkyl ring or a (C 5 -C 8 )cycloalkenyl ring having the following structure: [0084] wherein n is 0, 1, 2 or 3, where such (C 5 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is optionally substituted, and wherein the dashed line indicates an optional double bond at that position. In a non-limiting embodiment, the (C 5 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is substituted by one to three independently selected groups Z as defined above. [0085] In a preferred embodiment, X and Y are taken together with the carbon to which they are attached to form a cyclohexyl or cyclohexenyl ring, and most preferably a cyclohexyl ring. [0086] In a further preferred embodiment, X and Y are taken together with the carbon to which they are attached to form a cyclopentyl or cyclopentenyl ring, and most preferably a cyclopentyl ring. [0087] In a further preferred embodiment, the (C 5 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is not substituted. [0088] In a further preferred embodiment, the (C 5 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is monosubstituted. More preferably, X and Y are taken together with the carbon to which they are attached to form a monosubstituted cyclohexyl or monosubstituted cyclopentyl ring. [0089] In a further preferred embodiment, the (C 5 -C 8 )cycloalkyl ring or (C 5 -C 8 )cycloalkenyl ring is disubstituted. More preferably, X and Y are taken together with the carbon to which they are attached to form a disubstituted cyclohexyl or disubstituted cyclopentyl ring. [0090] Where X and Y are taken together with the carbon to which they are attached to form a cyclohexyl or cyclohexenyl ring, the ring is preferably substituted at the 3- or 4-position, and more preferably at the 4-position. [0091] Where X and Y are taken together with the carbon to which they are attached to form a cyclopentyl or cyclopentenyl ring, the ring is preferably substituted at the 3-position. [0092] In a further preferred embodiment, X and Y are taken together with the carbon to which they are attached to form: [0093] which is substituted with one to three independently selected groups Z as described above; [0094] wherein n is 0, 1, or 2. [0095] In a further preferred embodiment, n is 0 or 1. [0096] In a further preferred embodiment, n is 0; and the dashed line represents a double bond at that position. [0097] In a further preferred embodiment, n is 1. [0098] In a further preferred embodiment, the ring formed by X and Y taken together with the carbon to which they are attached is substituted by OH, ═O, ═NOH, CH 2 OH or [0099] or a combination thereof. [0100] In a further preferred embodiment, n is 0; the ring formed by X and Y taken together with the carbon to which they are attached is substituted by ═NOH; and the dashed line represents a double bond at that position. [0101] In a further preferred embodiment, n is 1; and the ring formed by X and Y taken together with the carbon to which they are attached is substituted by OH, ═O, ═NOH, CH 2 OH, or [0102] or a combination thereof. [0103] Where Z is a (C 2 -C 9 )heterocycloalkyl substituent, it is preferably a group of the formula: [0104] wherein m is 0, 1 or 2, and [0105] Q is CH 2 , NR 2 , O, S, SO, or SO 2 . [0106] In a further preferred embodiment, X and Y are taken together with the carbon to which they are attached to form a cyclohexyl, cyclohexenyl, cyclopentyl or cyclopentenyl ring that is monosubstituted with Z selected from the group consisting of OH, R 3 C(O)O—, R 3 C(O)O—(C 1 -C 6 )alkyl-, R 2 ON═, R 2 ON═(C 1 -C 6 )alkyl-, R 2 ON═CR 2 (C 1 -C 6 )alkyl-, —NR 2 (OR 2 ), R 4 S(O) 2 R 5 N—, and R 4 S(O) 2 R 5 N(C 1 -C 6 )alkyl-; wherein R 2 , R 3 , R 4 and R 5 are as defined above. [0107] In a further preferred embodiment, X and Y are taken together with the carbon to which they are attached to form a cyclohexyl or cyclopentyl ring that is monosubstituted with Z selected from the group consisting of OH, R 3 C(O)O—, R 3 C(O)O—(C 1 -C 6 )alkyl-, R 2 ON═, R 2 ON═(C 1 -C 6 )alkyl-, R 2 ON═CR 2 (C 1 -C 6 )alkyl-, -NR 2 (OR 2 ), R 4 S(O) 2 R 5 N—, and R 4 S(O) 2 R 5 N(C 1 -C 6 )alkyl-; wherein R 2 , R 3 , R 4 and R 5 are as defined above. [0108] In a further preferred embodiment, Z is OH. [0109] In a further preferred embodiment, Z is R 3 C(O)O—. [0110] In a further preferred embodiment, Z is R 3 C(O)O—(C 1 -C 6 )alkyl-. [0111] In a further preferred embodiment, Z is R 2 ON═, R 2 ON═(C 1 -C 6 )alkyl-, or R 2 ON═CR 2 (C 1 -C 6 )alkyl-. [0112] In a further preferred embodiment, Z is R 2 ON═. [0113] In a further preferred embodiment, Z is —NR 2 (OR 2 ). [0114] In a further preferred embodiment, Z is R 4 S(O) 2 R 5 N—. [0115] In a further preferred embodiment, Z is R 4 S(O) 2 R 5 N(C 1 -C 6 )alkyl-. [0116] In a non-limiting embodiment, the process of the present invention can be used to prepare a compound selected from the group consisting of: [0117] 4-cyclohexyl resorcinol; [0118] 4-cyclopentyl resorcinol; [0119] 4-(2,4-dihydroxyphenyl)cyclohexanol; [0120] 4-(2,4-Dihydroxyphenyl)cyclohexanone; [0121] 4-(2,4-Dihydroxyphenyl)cyclohexanone oxime; [0122] O-Methyl-4-(2,4-dihydroxyphenyl)cyclohexanone oxime; [0123] O-Benzyl-4-(2,4-dihydroxyphenyl)cyclohexanone oxime; [0124] 3-(2,4-dihydroxyphenyl)-2-cyclohexen-1-one; [0125] (±)-3-(2,4-Dihydroxyphenyl)cyclohexanone; [0126] 3-(2,4-Dihydroxyphenyl)-2-cyclohexen-1-one oxime; [0127] (±)-3-(2,4-Dihydroxyphenyl)cyclohexanone oxime; [0128] (±)-4-[3-(1-piperazinyl)cyclohexyl]-1,3-benzenediol; [0129] (±)-N-[3-(2,4-Dihydroxyphenyl)cyclohexyl]methanesulfonamide; [0130] (±)-4-[3-(Hydroxymethyl)cyclohexyl]-1,3-benzenediol; [0131] (±)-4-[3-(Hydroxyamino)cyclohexyl]-1,3-benzenediol; [0132] cis/trans-4-[4-(Hydroxymethyl)cyclohexyl]-1,3-benzenediol; [0133] cis/trans-4-(4-Hydroxy-4-methylcyclohexyl)-1,3-benzenediol; [0134] (±)-O-Methyl-3-(2,4-dihydroxyphenyl)cyclohexanone oxime; [0135] (±)-3-(2,4-Dihydroxyphenyl)-1-methylcyclohexanol; [0136] (±)-O-Benzyl-3-(2,4-dihydroxyphenyl)cyclohexanone oxime; [0137] 3-(2,4-Dihydroxyphenyl)-2-cyclopentenone oxime; [0138] (±)-3-(2,4-Dihydroxyphenyl)cyclopentanone; [0139] (±)-3-(2,4-Dihydroxyphenyl)cyclopentanone oxime; [0140] 4-(2,4-Dihydroxyphenyl)-3-cyclohexen-1-one; [0141] cis/trans-N-[4-(2,4-Dihydroxyphenyl)cyclohexyl]acetamide; [0142] cis-N-[4-(2,4-Dihydroxyphenyl)cyclohexyl]-1-butanesulfonamide; [0143] trans-N-[4-(2,4-Dihydroxyphenyl)cyclohexyl]methanesulfonamide; [0144] cis-N-[4-(2,4-Dihydroxyphenyl)cyclohexyl]methanesulfonamide; [0145] 4-[4-(4-Hydroxyphenyl)cyclohexyl]-1,3-benzenediol; [0146] cis/trans-Methyl[4-(2,4 -dihydroxyphenyl)cyclohexyl]acetate; [0147] trans-Methyl[4-(2,4-dihydroxyphenyl)cyclohexyl]acetate; [0148] cis-Methyl[4-(2,4-dihydroxyphenyl)cyclohexyl]acetate; [0149] trans-[4-(2,4-Dihydroxyphenyl)cyclohexyl]acetic acid; [0150] cis-[4-(2,4-Dihydroxyphenyl)cyclohexyl]acetic acid; [0151] cis/trans-[4-2,4-Dihydroxyphenyl)cyclohexyl]acetic acid; [0152] cis/trans-[4-(2,4-Dihydroxyphenyl)cyclohexyl]acetonitrile; [0153] cis/trans-4-[4-(2-Aminoethyl)cyclohexyl]-1,3-benzenediol; [0154] (±)-4-(3,3-Difluorocyclohexyl)-1,3-benzenediol; [0155] (±)-3-(2,4-Dihydroxyphenyl)cyclohexanecarboxamide; [0156] (±)-3-(2,4-Dihydroxyphenyl)-N-hydroxycyclohexanecarboxamide; [0157] (±)-3-(2,4-Dihydroxyphenyl)-N-ethylcyclohexanecarboxamide; [0158] (±)-4-[3-Hydroxy-3-(hydroxymethyl)cyclohexyl]-1,3-benzenediol; [0159] (±)-N-[3-(2,4-dihydroxyphenyl)cyclohexyl]acetamide; [0160] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl)4-(dimethylamino)benzoate; [0161] cis/trans-4-(2,4-Dihydroxyphenyl)cyclohexanecarboxylic acid; [0162] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl ethylcarbamate; [0163] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl cyclohexylcarbamate; [0164] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl4-tert-butylbenzoate; [0165] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl4-fluorobenzoate; [0166] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl4-trifluoromethylbenzoate; [0167] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl4-methoxybenzoate; [0168] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl4-methylbenzoate; [0169] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl4-chlorobenzoate; [0170] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl3,4-dimethylbenzoate; [0171] trans-4-(2,4-Dihydroxyphenyl)cyclohexyl3,4-dichlorobenzoate; [0172] trans-4-[4-(Phenylsulfanyl)cyclohexyl]-1,3-benzenediol; [0173] trans-4-[4-(Phenylsulfonyl)cyclohexyl]-1,3-benzenediol; [0174] [4-(2,4-Dihydroxyphenyl)cyclohexyl]methyl propionate; [0175] ethyl4-(2,4-dihydroxyphenyl)-1-hydroxycyclohexane carboxylate; [0176] cis/trans-4-[4-(hydroxyamino)cyclohexyl]-1,3-benzenediol; [0177] trans-4-[4-(methoxyamino)cyclohexyl]-1,3-benzenediol; [0178] and a pharmaceutically acceptable salt thereof. [0179] The term “resorcinol derivative”, as used herein, refers to a compound comprising a resorcinol ring monosubstituted at the 4-position, as defined above, and is represented by the structure of formula I. [0180] The term “alkyl”, as used herein, unless otherwise indicated, includes saturated monovalent hydrocarbon radicals having straight, branched or cyclic moieties or combinations thereof, which may or may not be further substituted. Any substituents or functional groups on the alkyl group, as indicated herein, can be substituted anywhere on the alkyl group where such substitutions are possible. [0181] The term “aryl”, as used herein, refers to phenyl or naphthyl optionally substituted with one or more substituents, preferably from zero to two substituents, independently selected from halogen, OH, (C 1 -C 6 )alkyl, (C 1 -C 6 ) alkoxy, amino, (C 1 -C 6 )alkylamino, di-((C 1 -C 6 )alkyl))amino, nitro, cyano and trifluoromethyl. Any substituents or functional groups on the aryl group, as indicated herein, can be substituted anywhere on the aryl group. [0182] The term “one or more substituents”, as used herein, refers to a number of substituents that equals from one to the maximum number of substituents possible based on the number of available bonding sites. [0183] The “halo”, as used herein, refers to halogen and, unless otherwise indicated, includes chloro, fluoro, bromo and iodo. [0184] The term “acyl”, as used herein, unless otherwise indicated, includes a radical of the general formula RCO wherein R is alkyl, alkoxy, aryl, arylalkyl, or arylalkyloxy and the terms “alkyl” or “aryl” are as defined above. [0185] The term “acyloxy”, as used herein, includes O-acyl groups wherein “acyl” is as defined above. [0186] (C 2 -C 9 )Heterocycloalkyl, when used herein, refers to pyrrolidinyl, tetrahydrofuranyl, dihydrofuranyl, tetrahydropyranyl, pyranyl, thiopyranyl, aziridinyl, oxiranyl, methylenedioxyl, chromenyl, isoxazolidinyl, 1,3-oxazolidin-3-yl, isothiazolidinyl, 1,3-thiazolidin-3-yl, 1,2-pyrazolidin-2-yl, 1,3-pyrazolidin-1-yl, piperidinyl, thiomorpholinyl, 1,2-tetrahydrothiazin-2-yl, 1,3-tetrahydrothiazin-3-yl, tetrahydrothiadiazinyl, morpholinyl, 1,2-tetrahydrodiazin-2-yl, 1,3-tetrahydrodiazin-1-yl, tetrahydroazepinyl, piperazinyl, chromanyl, etc. One of ordinary skill in the art will understand that the connection of said (C 2 -C 9 )heterocycloalkyl ring can be through a carbon atom or through a nitrogen heteroatom where possible. [0187] (C 2 -C 9 )Heteroaryl, when used herein, refers to furyl, thienyl, thiazolyl, pyrazolyl, isothiazolyl, oxazolyl, isoxazolyl, pyrrolyl, triazolyl, tetrazolyl, imidazolyl, 1,3,5-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,3-oxadiazolyl, 1,3,5-thiadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, 1,2,4-triazinyl, 1,2,3-triazinyl, 1,3,5-triazinyl, pyrazolo[3,4-b]pyridinyl, cinnolinyl, pteridinyl, purinyl, 6,7-dihydro-5H-[l]pyridinyl, benzo[b]thiophenyl, 5, 6, 7, 8-tetrahydro-quinolin-3-yl, benzoxazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzimidazolyl, thianaphthenyl, isothianaphthenyl, benzofuranyl, isobenzofuranyl, isoindolyl, indolyl, indolizinyl, indazolyl, isoquinolyl, quinolyl, phthalazinyl, quinoxalinyl, quinazolinyl, benzoxazinyl, etc. One of ordinary skill in the art will understand that the connection of said (C 2 -C 9 )heterocycloalkyl rings can be through a carbon atom or through a nitrogen heteroatom where possible. [0188] Compounds of formula I may contain chiral centers and therefore may exist in different enantiomeric and diastereomeric forms. This invention relates to preparation of all optical isomers, stereoisomers and tautomers of the compounds of formula I, and mixtures thereof. [0189] Formula I, as defined above, also includes compounds identical to those depicted but for the fact that one or more hydrogen, carbon or other atoms are replaced by isotopes thereof. Such compounds may be useful as research and diagnostic tools in metabolism pharmacokinetic studies and in binding assays. [0190] The present invention also relates to preparation of the pharmaceutically acceptable acid addition and base addition salts of any of the aforementioned compounds of formula I. The acids which are used to prepare the pharmaceutically acceptable acid addition salts of the aforementioned base compounds of this invention are those which form non-toxic acid addition salts, i.e., salts containing pharmacologically acceptable anions, such as the hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate, acetate, lactate, citrate, acid citrate, tartrate, bitartrate, succinate, maleate, fumarate, gluconate, saccharate, benzoate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate and pamoate (i.e., 1,1-methylene-bis-(2-hydroxy-3-naphthoate)) salts. [0191] The present invention also provides various intermediate compounds useful in the preparation of wide variety of resorcinol derivatives. [0192] The present invention provides an intermediate compound of formula (4), where W, X and Y are as defined above. [0193] In a preferred embodiment, the intermediate compound of formula (4) has the structure of formula (4a), [0194] where W is as defined above, and n is 0, 1, 2 or 3. [0195] In a further preferred embodiment, the intermediate compound of formula (4) has the structure of formula (4b) or (4c), [0196] where W is as defined above. [0197] In a further preferred embodiment, the intermediate compound of formula (4) has the structure of formula (4d), [0198] where W and Z are as defined above, and n is 0, 1, 2 or 3. [0199] In a further preferred embodiment, the intermediate compound of formula (4) has the structure of formula (4e) or (4f), [0200] where W and Z are as defined above. [0201] In a further preferred embodiment, the intermediate compound of formula (4) has the structure of formula (4g), [0202] where W and each Z are as defined above, and n is 0, 1, 2 or 3. [0203] In a further preferred embodiment, the intermediate compound of formula (4) has the structure of formula (4h) or (4i), [0204] where W and each Z are as defined above. [0205] The present invention further provides an intermediate compound of formula (5), [0206] where Q, W, X and Y are as defined above. [0207] In a preferred embodiment, the intermediate compound of formula (5) has the structure of formula (5a) [0208] wherein Q and W are as defined above, and n is 0, 1, 2, or 3. [0209] In a further preferred embodiment, the intermediate compound of formula (5) has the structure of formula (5b) or (5c) [0210] wherein Q and W are as defined above. [0211] In a further preferred embodiment, the intermediate compound of formula (5) has the structure of formula (5d) [0212] wherein Q, W and Z are as defined above, and n is 0, 1, 2, or 3. [0213] In a further preferred embodiment, the intermediate compound of formula (5) has the structure of formula (5e) or (5f), [0214] where Q, W and Z are as defined above. [0215] In a further preferred embodiment, the intermediate compound of formula (5) has the structure of formula (5g) [0216] wherein Q, W and Z are as defined above, and n is 0, 1, 2, or 3. [0217] In a further preferred embodiment, the intermediate compound of formula (5) has the structure of formula (5h) or (5i), [0218] wherein Q, W and each Z are as defined above. [0219] The present invention further provides an intermediate compound of formula (5′), [0220] wherein Q, X and Y are as defined above. [0221] In a preferred embodiment, the intermediate compound of formula (5′) has the structure of formula (5′a), [0222] where Q is as defined above, and n is 0, 1, 2 or 3. [0223] In a further preferred embodiment, the intermediate compound of formula (5′) has the structure of formula (5′b) or (5′c), [0224] wherein Q is as defined above. [0225] In a further preferred embodiment, the intermediate compound of formula (5′) has the structure of formula (5′d) or (5′e), [0226] wherein Q and Z are as defined above. [0227] In a further preferred embodiment, the intermediate compound of formula (5′) has the structure of formula (5′f) or (5′g), [0228] wherein Q and each Z are as defined above. DETAILED DESCRIPTION OF THE INVENTION [0229] The process of the present invention is described in the following reaction schemes and discussion. [0230] Referring to Scheme 1, compounds of formula (2) can be prepared starting with compound (1), which is commercially available (Aldrich Chemical Co.). A suitable protecting group can be selected as will be evident to those of skill in the art. An example of a suitable protecting group is benzyl. Conversion to compounds of formula (2) can occur under standard conditions. For instance, where the protecting group is benzyl, condensation can occur between compound (1) and benzyl alcohol with the removal of water using Dean-Stark apparatus. Condensation of compounds of formula (2) with compounds of formula (3) may occur using standard techniques, for instance, treatment of compounds of formula (2) with a base, such as lithium diisopropylamide or lithium hexamethyidisilazide, in an ethereal solvent followed by the addition of a compound of formula (3) would give compounds of formula (4). When W is H, condensation of compounds of formula (2) with compounds of formula (3) requires the use of at least two equivalents of a suitable base such as lithium diisopropylamide in an suitable solvent such as tetrahydrofuran, with a suitable co-solvent such as hexamethylphosphoramide. Treatment of compounds of formula (4) with a suitable halogenating reagent such as, for example, N-bromosuccinimide in a chlorinated solvent, such as dichloromethane or chloroform, at about room temperature, can give compounds of formula (5) where Q is halo, and preferably bromo. Where W is H, the compound of formula (5) may exist in equilibrium with the compound of formula (5′). Alternatively, where W is H, compounds of formula (5′) may be prepared directly from compounds of formula (4) by treatment of the compound of formula (4) with a suitable halogenating agent. The process of the present invention is intended to encompass each of these various synthesis routes. [0231] Compounds of formula (6) may then be generated from compounds of formula (5) or (5′) under suitable conditions. Such conditions may involve treating compounds of formula (5) or (5′) with a base such as, e.g., 1,8-diazobicyclo[5.4.0]undec-7-ene in a suitable solvent such as N,N-dimethylformamide at about room temperature. Compounds of formula I(a) may be generated using standard techniques, e.g., treating compounds of formula (6) with triethylsilane in the presence of a Lewis acid such as boron trifluoride in a chloronated solvent, followed by suitable conditions to remove the protecting group, or hydrogenating compounds of formula (6) under standard conditions, would yield compounds of formula I(a). Compounds of formula (7) may be generated from compounds of formula (5), (5′) or (6) under suitable reaction conditions. Such conditions may involve treating compounds of formula (5) or (5′) or (6) with a base such as, e.g., 1,8-diazobicyclo[5.4.0]undec-7-ene in a suitable solvent such as N,N-dimethylformamide at about 140° C. Other solvents such as toluene or N-methylpyrrolidinone may also be useful for this purpose. Subjection of compounds of formula (7) to standard hydrogenation conditions, e.g., hydrogen gas and palladium on charcoal in ethanol, yields compounds of the general formula I(a) when the protecting group was benzyl. Where W is a protecting group, compounds of formula I(b) can be formed by treating compounds of formula (7) to standard conditions that will be obvious to those with skill in the art. Compounds of formula I(b) can in turn be converted to compounds of formula I(a) by standard hydrogenation conditions, such as described above. Compounds I(a) and I(b) fall within the scope of formula I. [0232] Referring to Scheme 2 as an example of a more specific scheme, compounds of formula (8) can be prepared starting with compound (1), which is commercially available (Aldrich Chemical Co.). Conversion to compounds of formula (8) can occur under standard conditions, for instance where the protecting group is benzyl, condensation can occur between compound (1) and benzyl alcohol with the removal of water using Dean-Stark apparatus. Condensation of compounds of formula (8) with compounds of formula (9) may occur using standard techniques, for instance, treatment of compounds of formula (8) with a base such as lithium diisopropylamide in an ethereal solvent followed by the addition of a compound of formula (9) would give compounds of formula (10). Treatment of compounds of formula (10) with a suitable brominating reagent, such as N-bromosuccinimide in a chlorinated solvent at about room temperature, can give compounds of formula (11). Compounds of formula (12) may then be generated from compounds of formula (11) under suitable reaction conditions. Such conditions may involve treating compounds of formula (11) with a base such as 1,8-diazobicyclo[5.4.0]undec-7-ene in a suitable solvent such as N,N-dimethylformamide at about 140° C. Subjection of compounds of formula (12) to standard hydrogenation conditions, e.g., hydrogen gas and palladium on charcoal in an ethanol/tetrahydrofuran mixture, yields compounds of the general formula I(c) when the protecting group was benzyl. Compounds of formula I(d) may then be obtained by subjecting compounds of formula I(c) to acidic conditions. Compounds of formulae I(c) and I(d) both fall within the scope of formula I. [0233] It will be appreciated by those of skill in the art that in the processes described above, the functional groups of intermediate compounds may need to be protected. The use of protecting groups is well-known in the art, and is fully described, among other places, in: Protecting Groups in Organic Chemistry, J. W. F. McOmie, (ed.), 1973, Plenum Press; and in: Protecting Groups in Organic Synthesis, 2 nd edition, T. W. Greene & P. G. M. Wutz, 1991, Wiley-Interscience, which are incorporated herein by reference in their entirety. [0234] Resorcinol derivatives prepared according to the process described herein are useful for all of the purposes previously described for these types of compounds. For example, resorcinol derivatives useful as skin-lightening agents or for other cosmetic purposes can be prepared according to the process of the present invention. [0235] Where resorcinol derivatives prepared according to the present invention are useful as skin-lightening agents, these may be used to treat disorders of human pigmentation, including solar and simple lentigines (including age/liver spots), melasma/chloasma and postinflammatory hyperpigmentation. Such compounds reduce skin melanin levels by inhibiting the production of melanin, whether the latter is produced constitutively or in response to UV irradiation (such as sun exposure), and typically by inhibition of the enzyme tyrosinase. Active skin-lightening compounds prepared according to the present invention can be used to reduce skin melanin content in non-pathological states so as to induce a lighter skin tone, as desired by the user, or to prevent melanin accumulation in skin that has been exposed to UV irradiation. They can also be used in combination with skin peeling agents (including glycolic acid or trichloroacetic acid face peels) to lighten skin tone and prevent repigmentation. The appropriate dose regimen, the amount of each dose administered, and specific intervals between doses of the active compound will depend upon the particular active compound employed, the condition of the patient being treated, and the nature and severity of the disorder or condition being treated. Preferably, the active compound is administered in an amount and at an interval that results in the desired treatment of or improvement in the disorder or condition being treated. [0236] An active compound prepared according to the process of the present invention can also be used in combination with sun screens (UVA or UVB blockers) to prevent repigmentation, to protect against sun or UV-induced skin darkening or to enhance their ability to reduce skin melanin and their skin bleaching action. An active compound prepared according the process of the present invention can also be used in combination with retinoic acid or its derivatives or any compounds that interact with retinoic acid receptors and accelerate or enhance the invention's ability to reduce skin melanin and skin bleaching action, or enhance the invention's ability to prevent the accumulation of skin melanin. An active compound prepared according to the present invention can also be used in combination with 4-hydroxyanisole. [0237] The active compounds prepared according to the process of the present invention can also be used in combination with ascorbic acid, its derivatives and ascorbic-acid based products (such as magnesium ascorbate) or other products with an anti-oxidant mechanism (such as resveratrol) which accelerate or enhance their ability to reduce skin melanin and their skin bleaching action. [0238] Skin-lightening active compounds prepared according to the present invention are generally administered in the form of pharmaceutical compositions comprising at least one of the compounds of formula (I), together with a pharmaceutically acceptable vehicle or diluent. Such compositions are generally formulated in a conventional manner utilizing solid or liquid vehicles or diluents as appropriate for topical administration, in the form of solutions, gels, creams, jellies, pastes, lotions, ointments, salves, aerosols and the like. [0239] Examples of vehicles for application of the active compounds of this invention include an aqueous or water-alcohol solution, an emulsion of the oil-in-water or water-in-oil type, an emulsified gel, or a two-phase system. Preferably, the compositions according to the invention are in the form of lotions, creams, milks, gels, masks, microspheres or nanospheres, or vesicular dispersions. In the case of vesicular dispersions, the lipids of which the vesicles are made can be of the ionic or nonionic type, or a mixture thereof. [0240] In a skin-lightening composition comprising a resorcinol derivative prepared according to the process of the present invention, the concentration of the resorcinol derivative is generally between 0.01 and 10%, preferably between 0.1 and 10%, relative to the total weight of the composition. [0241] A skin-lightening resorcinol derivative prepared according to the present invention can be conveniently identified by its ability to inhibit the enzyme tyrosinase, as determined by any standard assay, such as those described below. [0242] 1. Tyrosinase (DOPA oxidase) assay using cell lysate: [0243] Human melanoma cell line, SKMEL 188 (licensed from Memorial Sloan-Kettering), is used in the cell lysate assay and the screen. In the assay, compounds and L-dihydroxyphenylalanine (L-DOPA) (100 μg/ml) are incubated with the cell lysates containing human tyrosinase for 8 hrs before the plates are read at 405 nm. Potency of the compounds in DOPA oxidase assay is correlated very well with that in tyrosine hydroxylase assay using 3 H-tyrosine as a substrate. [0244] 2. Melanin assay in human primary melanocytes: [0245] Compounds are incubated with human primary melanocytes in the presence of α-melanocyte stimulating hormone (α-MSH) for 2-3 days. Cells are then lysed with sodium hydroxide and sodium dodecyl sulfate (SDS) and melanin signals are read at 405 nm. Alternatively, 14 C-DOPA is added to the cells in combination with tyrosinase inhibitors and acid-insoluble 14 C-melanin is quantitated by a scintillation counter. IC 50 's reflect the inhibitory potency of the compounds in the new melanin synthesis that was stimulated by α-MSH. [0246] 3. Tyrosine kinase assay (TK): [0247] TK assays can be performed using purified tyrosine kinase domains of c-met, erb-B2, or IGF-r. A specific antibody against phosphorylated tyrosine residue is used in the assay. Colorimetric signals are generated by horseradish peroxidase, which is conjugated to the antibody. [0248] 4. Human skin equivalent model: [0249] A mixture of human melanocytes and keratinocytes is grown in an air-liquid interphase. This tissue culture forms a three dimensional structure that histologically and microscopically resembles the human skin epidermis. Test compounds are added on top of the cells to mimic topical drug application. After incubation with the compounds (10 μM) for 3 days, the cells are washed extensively and lysed for DOPA oxidase assay. [0250] 5. IL-1 assay (Interleukin-1 assay): [0251] An IL-1α ELISA assay (R&D system) can be used to evaluate the effect of compounds on IL-1 secretion in a human skin equivalent model. IL-1α is a pro-inflammatory cytokine and plays a role in UV-induced skin inflammation. [0252] 6. In vivo study: [0253] Black or dark brown guinea pigs with homogeneous skin color can be used in this study. A solution of the test compound of formula I (5% in ethanol:propylene glycol, 70:30) and the vehicle control are applied to the animals twice daily, 5 days per week for 4-8 weeks. Using this assay, depigmentation can be determined by subtracting the light reflectance of untreated skin from the light reflectance of treated skin. [0254] The present invention is illustrated by the following examples. It will be understood, however, that the invention is not limited to the specific details of these examples. Melting points are uncorrected. Proton nuclear magnetic resonance spectra (400 MHz 1 H NMR) were measured for solutions in d 6 -DMSO, CDCl 3 , or d 4 -MeOH, and peak positions are expressed in parts per million (ppm) downfield from tetramethylsilane (TMS). The peak shapes are denoted as follows: s, singlet; d, doublet; t, triplet; q, quartet, m, multiplet, b, broad. [0255] The following examples are illustrative only, and are not intended to limit the scope of the present invention. EXAMPLES Intermediate 1 3-(Benzyloxy)-2-cyclohexen-1-one [0256] To a round bottomed flask equipped with magnetic stirrer and Dean Stark apparatus was added 1,3-cyclohexanedione (70.0 g, 624 mmol), toluene (500 ml), p-toluenesulfonic acid monohydrate (1.68 g, 8.83 mmol) and benzyl alcohol (65.6 g, 606 mmol). The resulting solution was heated under reflux for 2 hr. The reaction mixture was cooled to room temperature and washed with saturated aqueous sodium carbonate solution (4×50 ml). The organic layer was washed with brine (50 ml), dried over magnesium sulfate, filtered and concentrated in vacuo, affording a brown oil which crystallised upon standing. The crude crystalline material was slurried in isopropyl ether (100 ml) and stirred at 0° C. for 2 hr. The mixture was filtered and the crystalline material was washed with ice cold isopropyl ether (3×100 ml) followed by cold petroleum ether (100 ml). The resulting solid was dried overnight under reduced pressure to furnish the title compound (85.3 g, 68%). m/z (ES + ) 203 (M+H + ). Intermediate 2 (±)-3-(Benzyloxy)-6-(8-hydroxy-1,4-dioxaspiro[4.5]dec-8-yl)-2-cyclohexen-1-one [0257] To a round bottomed flask equipped with magnetic stirrer was added anhydrous tetrahydrofuran (600 ml) and diisopropylamine (38.1 ml, 272 mmol). The stirred solution was cooled to −78° C. and n-butyl lithium (113.4 ml, 272 mmol, 2.4 M in hexanes) was added dropwise via syringe in 20 ml portions. The resulting yellow solution was stirred for 35 min at −78° C., then 3-(benzyloxy)-2-cyclohexen-1-one (50.0 g, 248 mmol) was added as a solution in anhydrous tetrahydrofuran (100 ml). The solution was stirred for 1 hr prior to the addition of cyclohexane-1,4-dione monoethylene ketal (38.7 g, 248 mmol) as a solution in anhydrous tetrahydrofuran (100 ml). The solution was stirred for 2 hr at −78° C., then allowed to warm slowly to room temperature over 1 hr. Saturated aqueous ammonium chloride (80 ml) was added, followed by dichloromethane (700 ml) and the mixture was stirred until no solids remained. The layers were separated and the aqueous phase extracted with dichloromethane (2×100 ml). The combined organic layers were washed with brine (50 ml), dried over magnesium sulfate, then concentrated in vacuo. Trituration of the resulting solid with methanol afforded the title compound (78.4 g, 88%). m/z (ES + ) 359 (M+H + ). Intermediate 3 (±)-1-(Benzyloxy)-6-bromo-3-(1,4-dioxaspiro[4.5]dec-8-yl)-2-oxabicyclo[2.2.2]octan-5-one [0258] A round bottomed flask equipped with magnetic stirrer was charged with (±)-3-(benzyloxy)-6-(8-hydroxy-1,4-dioxaspiro[4.5]dec-8-yl)-2-cyclohexen-1-one (78.4 g, 219 mmol) and dichloromethane (600 ml). To the stirred solution was added N-bromosuccinimide (40.9 g, 230 mmol) in one portion, followed by aqueous hydrobromic acid (3 drops, 48% aqueous solution). The resulting solution was stirred at room temperature for 2 hr, then poured into a separating funnel containing aqueous sodium metabisulfite solution (150 ml) and dichloromethane (200 ml) and the funnel was shaken vigorously. The layers were separated and the organic layer was washed with brine (200 ml), dried over magnesium sulfate, filtered, then concentrated in vacuo to give a solid. Trituration with methanol (500 ml) afforded the title compound (82.8 g, 86%) as a white solid. m/z (ES + ) 437 and 439 [(1:1), M+H + ]. Intermediate 4 5-(Benzyloxy)-2-(1,4-dioxaspiro[4.5]dec-7-en-8-yl)phenol [0259] A round bottomed flask was charged with (±)-1-(benzyloxy)-6-bromo-3-(1,4-dioxaspiro[4.5]dec-8-yl)-2-oxabicyclo[2.2.2]octan-5-one (36 g, 82.4 mmol) and anhydrous N,N-dimethylformamide (300 ml). To the stirred solution was added 1,8-diazabicyclo[5.4.0]undec-7-ene (13.6 ml, 90.6 mmol) in one portion before heating to 140° C. for 19 hr with vigorous stirring. The reaction mixture was allowed to cool to room temperature and most of the solvent was removed under reduced pressure. The remaining oil was partitioned between dichloromethane (500 ml) and water (100 ml), and the layers were separated. The organic phase was washed with water (2×100 ml) followed by brine (100 ml). The organic phase was dried over magnesium sulfate, filtered and concentrated in vacuo to afford a brown solid which was adsorbed onto silica gel. Purification via flash column chromatography (SiO 2 , dichloromethane then ethyl acetate/petroleum ether, 3:7, v/v) furnished an off white solid which was slurried in methanol (150 ml). The slurry was stirred for 20 min, filtered and washed with methanol (50 ml). The title compound (18.2 g, 65%) was isolated as a white solid after removal of excess solvent under reduced pressure. m/z (ES + ) 339(M+H + ). Example 1 4-(1,4-Dioxaspiro[4.5]dec-8-yl)-1,3-benzenediol [0260] A round bottomed flask equipped with magnetic stirrer was charged with 5-(benzyloxy)-2-(1,4-dioxaspiro[4.5]dec-7-en-8-yl)phenol (14.5 g, 42.8 mmol) and tetrahydrofuran (50 ml). The stirred mixture was gently heated until a solution formed, after which the solution was allowed to cool to room temperature. Ethanol (100 ml) and palladium (4.54 g, 10% on activated carbon) were added sequentially. The reaction vessel was then evacuated, placed under a hydrogen atmosphere and stirred vigorously for 24 hr. The reaction mixture was filtered through a celite plug, washing with ethyl acetate. The filtrate was concentrated in vacuo to give an off white solid. The crude solid was slurried in dichloromethane (200 ml), then collected on a sinter, affording the title compound (10.2 g, 95%) as a white solid. m/z(ES + )251(M+H + ). Example 2 4-(2,4-Dihydroxyphenyl)cyclohexanone [0261] A round bottomed flask equipped with magnetic stirrer was charged with 4-(1,4-dioxaspiro[4.5]dec-8-yl)-1,3-benzenediol (11.3 g, 45.2 mmol), acetone (250 ml) and water (50 ml). To the stirred solution was added pyridinium p-toluenesulfonate (1.14 g, 4.52 mmol) in one portion and the reaction mixture was then heated under reflux for 8 hr. After allowing the reaction mixture to cool to room temperature, most of the acetone was removed in vacuo and the remaining mixture was partitioned between ethyl acetate (200 ml) and water (50 ml). The aqueous layer was extracted with ethyl acetate (3×50 ml) and the combined organic layers were washed with brine (30 ml), dried over magnesium sulfate, filtered and concentrated under reduced pressure to afford an off-white powder. After washing the powder with dichloromethane (100 ml) and removal of excess solvent under reduced pressure, the title compound (9.30 g, 100%) was obtained as an off-white powder. m/z (ES + ) 207 (M+H + ); δ H (CD 3 OD) 1.84-1.97 (2H, m), 2.15-2.23 (2H, m), 2.36-2.45 (2H, m), 2.58-2.68 (2H, m), 3.39 (1H, tt), 6.26 (1H, dd), 6.34 (1H, d), 6.96 (1H, d). [0262] All patents, patent applications, and publications cited above are incorporated herein by reference in their entirety. [0263] The present invention is not to be limited in scope by the specific embodiments described herein, which are intended as single illustrations of individual aspects of the invention, and functionally equivalent methods and components are within the scope of the invention. Indeed, various modifications of the invention, in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.

The present invention relates to an improved process for preparing 4-substituted resorcinol derivatives, and intermediate compounds useful in the preparation of such resorcinol derivatives.

This invention relates to an improvement in U.S. Pat. No. 5,319,694 to Incral et al. for METHOD FOR OBTAINING THE IMAGE OF THE INTERNAL STRUCTURE OF AN OBJECT, issued Jun. 7, 1994. Specifically, a diffraction system and preferred beam path is set forth which utilizes a substantial solid angle of energy from a conventional X-ray point source to enable this technique to be practically applied. An X-ray imaging system using diffractive X-ray optics allows low dose, high definition, three dimensional imaging, ideal for Mammography. BACKGROUND OF THE INVENTION The state of the art in medical imaging has provided modalities such as enhanced ultrasound, nuclear magnetic resonance, light scattering/absorption, and nuclear to complement X ray imaging. In addition, X ray imaging has been improved by energy optimization with filters and targets, Compton scatter control, and more sensitive higher resolution photoluminescent screen film combinations. More recently, digital data acquisition and computer enhancement is being considered to segregate relevant data from non-relevant (noise), and perform computer assisted interpretations. None of these developments offer the desired complement of performance and cost. The elimination of radiation dose known to cause cancer by MRI or ultrasound techniques is a notable benefit, but the desired soft tissue definition and resolution has not been obtained. Such definition and resolution would allow, for example, the identification of microtumors less than one millimeter in diameter associated with incipient malignancy. In addition, the high cost, the learning curve in image interpretation, and the inability to accommodate real time invasive procedures has limited the growth of many of these new technologies in spite of superior soft tissue definition as compared to X ray. The Mammography application is exceptionally demanding in that extremely good resolution and soft tissue differentiation is necessary to identify the early stages of cancer, i.e. microcalcifications or microtumors. The "radiologically dense breast" further complicates this objective with a high degree of Compton scatter occurring, requiring a variety of scatter control measures. Many patents address solutions to these problems in energy optimization with filters and targets, slot scanning to reduce Compton scatter, grid design to reduce scatter, and voltage and current control algorithms to control exposure with varying thickness. Digital mammography may be of great potential in extracting relevant data in assessing cancer, but the non-obvious scientific basis, in combination with the perceived possibility of increasing an already high false positive cancerous detection rate has made its acceptance slow. In addition, evidence suggests that excessive radiation dose in Mammography remains a cancer risk. The overall Breast care application requires initial large volume low risk screening, real time imaging for needle biopsy assist, and three dimensional imaging for treatment planning. Many patents address these applications including system design, clinician/patient ergonomics, field size collimation, stereoscopic real time imaging embodiments, and three dimensional imaging. The evolution of digital imaging technology, particularly for mammography has resulted in patents on detectors in conjunction with methods such as slot scanning. The use of diffractive X-ray optics in imaging has been limited primarily to the use of synchrotron radiation, but some work has been done applying diffractive optics with electron target approaches. None of these approaches have been satisfactory concepts for mammography. In U.S. Pat. No. 5,319,694 to Ingal et al. for METHOD FOR OBTAINING THE IMAGE OF THE INTERNAL STRUCTURE OF AN OBJECT issued Jun. 7, 1994, the approach described by Ingal et al. can image only a small area with a lengthy exposure time, inappropriate for mammography. However, it is the purpose of this disclosure to utilize the technique of Ingal et al. in a practical embodiment for soft tissue imaging, such as that required in mammography. DEFINITION OF TERMS In the following description of a diffractive X-ray technique, it will be necessary to describe toric diffraction surfaces and the X-ray beams generated by reflection from crystals. So that a clear set of definitions can be presented, the following definitions are offered. Toric axis A T --the axis about which the closed curve is rotated to generate a torus. In the following disclosure, the X-ray source is located on this axis. Toric radius R T --the distance to the axis about which the closed curve (usually a circle) is rotated to generate a toroid. Diffraction radius R 1 --a toric radius defining the toric surface from which diffraction occurs. Crystal matrix radius R 2 --a toric radius defining the toric surface from which crystal alignment occurs. Monochromatic X-ray--a monoenergetic X-ray usually created by Bragg diffraction from an asymmetrical crystal surface where the diffracting surface is usually in one (toric) plane and the surface from which crystal alignment occurs is usually in a second and different toric plane. Line conjugate--a line or slit through which all X-rays pass usually as the result of a toric diffraction surface diffracting the X-rays from a point source. SUMMARY OF THE INVENTION An X-ray imaging system utilizing diffractive X-ray examination is utilized which includes an interrogating X-ray path from a conventional broad band X-ray source having a standard emission point. X-rays from the X-ray source impinge on a toric monochronometer having monochromatic Bragg X-ray diffraction occurring resulting in monochromatic X-ray diffraction. The toric monochronometer is preferably provided with a diffraction radius and crystal matrix radius providing asymmetric diffraction. In the asymmetric diffraction the point source is relatively distant and the diffracted monochromatic X-ray is focused to and incident on a line conjugate within a slit aperture stop for radiation confinement of all but the diffracted monochromatic X-rays. X-rays exiting the slit aperture stop expand and form a scanning beam and pass through the specimen (usually soft tissue) being examined. In passing through the specimen,. the X-rays receive image information by absorption, critical angle scattering, and, refraction, dependent upon the specimen structure. The X-rays are then incident on a toric detection crystal where monochromatic Bragg X-ray diffraction again occurs leaving the image revealed by absorption, and the rejection of critical angle scattering, and, refraction which occurred in the specimen at the analyzer crystal array. The diffracted monochromatic X-rays with the specimen induced images are then directed to an X-ray detector for image processing. The preferred embodiment includes a mammography apparatus in which each mammary is swept and scanned linearly or rotationally by an oblong beam (in the order of 3×24 centimeters) with scan direction between nipple and chest. Due to beam expansion from the slit aperture stop to the toric detection crystal, mammary tissue at varied elevations from the slit aperture stop provides differing relative motion for mammary tissue at each elevation. This enables apparent differential velocities of observed image features to be segregated by apparent scan velocity utilizing factor analysis and singular value decomposition. Image processing actually segregates the soft-tissue images by imaging planes taken normal to the mean path of the expanding beam. To enable construction of virtually any required diffracting surface, a technique of segmenting and bending diffracting crystals is disclosed. First, crystal segments and segment holders are generated with toric boundaries about the X-ray source. Thereafter, a crystal segment holder is machined with diffraction radius R 1 . The crystal segment is machined on the back or holder addressed surface with the convex surface having crystal matrix radius R 2 . This convex surface of the crystal segment is then bonded to the holder. Finally, the finished surface of the crystal in the holder is then machined with diffraction radius R 1 . When an entire segmented diffracting surface is constructed of diffracting segments fastened in this manner, the segment diffracting surface enables X-ray energy to be gathered from a conventional X-ray source over a relatively large solid angle. The segmented surface causes diffraction from that source with directionality required for the particular imaging task at hand. Here that technique is used with the toric X-ray monochronometer and toric detection crystal in the preferred mammography embodiment. OBJECTS AND ADVANTAGES U.S. Pat. No. 5,319,694 to Ingal et al. for METHOD FOR OBTAINING THE IMAGE OF THE INTERNAL STRUCTURE OF AN OBJECT clearly shows the potential advantages of imaging by virtue of mechanisms supplemental to absorption, i.e. refraction and critical angle scattering in small animals. This disclosure expands on the prior art primarily in the invention of an X-ray optics scheme to allow a large area to be imaged with a higher intensity while still using a conventional X-ray electron target rotating an anode X-ray source. This is accomplished with arrays of Johansson toroidally curved monochromator crystals for both the analyzer and monochromator in a mirroring configuration as shown in FIGS. 1 and 2. An additional benefit over U.S. Pat. No. 5,319,694 to Ingal et al. for METHOD FOR OBTAINING THE IMAGE OF THE INTERNAL STRUCTURE OF AN OBJECT is the reduction of monochromators before the patient from two to one, and the further reduction of scattered stray radiation from the crystal from irradiating the patient. The monochromatic nature of the beam impinging on the patient reduces patient surface dose by up to a factor of ten. Another additional benefit is the reduction in required dose by using a reflection analyzer monochromator where the beam is not split into two parts. This reduces the dose to the patient by a factor of two. The data enhancement associated with the two beams is achieved herein by digitally integrating over specified parts of the analyzer rocking curve, and digital subtraction. An additional benefit is the elimination of any Bucky scatter grid, which reduces the patient exposure by an additional factor of three. An additional benefit to this configuration with a diverging/converging beam is the ability to magnify the image of the object. An additional benefit with a digital cooled CCD tiled array detector is a reduction in patient exposure by up to an additional factor of five. An additional benefit with the CCD digital detector is the ability with boundary intensity detectors to extend the linear dynamic range of detection, to minimize patient exposure, and obtain good imaging of all parts of the breast, including skin line. An additional benefit of this invention with a diverging/converging beam envelope and effective line source is the ability to do three dimensional imaging by virtue of the differential velocity, where the high aspect ratio beam envelope is linearly scanned in one dimension. The deconvolution process not only offers 3D imaging, but image enhancement in the volume of interest. An additional benefit is the reduction in the need for breast compression, by virtue of lower inherent surface dose, elimination of Compton scatter image degradation, increased dynamic range of detection, and ability to deconvolute overlaying image features (three dim imaging). Another benefit of this invention is that is capable of either digital or film detection. A unique mechanical embodiment to provide these capabilities is presented. A unique operational systems description is presented. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a mammography apparatus constructed utilizing the diffraction X-ray technique of this invention; FIG. 2 is the apparatus of FIG. 1 illustrating an X-ray ray trace with the toric radius R T ; FIG. 3 is the apparatus of FIG. 1 illustrating an X-ray ray trace in side elevation section illustrating rotational scan; FIG. 4 is the apparatus of FIG. 1 illustrating an X-ray ray trace showing linear scanning of the beam; FIG. 5 illustrates a perspective view of piezoelectric micropositioners for adjusting one of the crystal arrays; FIG. 6 is a table illustrating actuation of micropositioners set forth in FIG. 5; FIG. 7 illustrates in side elevation a crystal; FIG. 8 is the diffraction path of the apparatus of FIG. 1 with only the diffracting and segmented crystals being shown; FIG. 9 is a plan view from the conventional point X-ray source past the two segmented diffracting surfaces utilized with this invention, it being remembered that the traced diffracting path is not in the plane of the view; FIG. 10 is a prior art detail of the X-ray source illustrating the principle that the X-ray source must lie on the Roland circle of the monochronometer crystal and further illustrating that for practical purposes the X-ray source is not a point source but does have specific dimension; FIG. 10 illustrates the well known Johansson Curvature illustrating how the combination of crystal structure curvature and diffracting surface curvature act together to provide diffraction from a crystal surface; FIG. 11 is a view of a soft tissue specimen having the X-rays of this invention pass through the specimen at the interrogating interval illustrating specifically how refracted, scattered, and absorbed X-ray impart image information to the remain transmitted rays; FIG. 12 illustrates the selectivity of various diffraction crystals that can be utilized with this invention; FIG. 13A and 13B illustrate respectively a side elevation section and plan view of a detector useful with this invention; FIG. 14 is a schematic view of the scan of this invention illustrating how the apparent difference in scan velocity can be utilized to examine the scanned specimen in segments taken normal to the mean scan direction of the interrogating X-rays; FIG. 15 illustrates a specialized lathe useful in producing the segmented diffracting surfaces utilized in this invention; FIGS. 16A, 16B, and 16C illustrates respective side elevation, expanded detail, and plan of a mount for one of the crystal segments utilized herein; FIG. 17A and 17B illustrates a crystal segment utilized with this invention; FIG. 18A and 18B illustrates the mount and crystal segment bonded together with the final finished surface place on the crystal structure within the mount; FIG. 19 is a block diagram of the image detection scheme of this invention; FIG. 20 is a table explaining sequence of operation of the apparatus of FIG. 20; FIG. 21 illustrates a crystal array doublet; FIG. 22A and 22B are schematics useful in understanding the scan protocol of this invention; FIG. 23A and 23B are respective schematics useful in explaining the scan format of this invention; FIG. 24 is a schematic illustrating the off axis utilization of this technique where X-rays to the analyzer crystal array are not co-linear with X-rays from the crystal monochromator array; FIG. 25 is a scan schematic of an alternate embodiment of this invention; and, FIG. 26 illustrates an array of diffraction doublets and the ray traces generated by the doublets imparting an improved resolution to the generated images. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 and 2 shows the preferred embodiment of the invention of the X-ray diffraction system. Conventional rotating anode X-ray tube 14 generates X-rays using a target material of choice, either copper, moly, silver, rhodium, or tungsten. The objective is to utilize the k alpha emission line of interest, depending on the thickness of the patient. The thicker the patient, the higher the energy necessary to minimize surface dose, and maximize detectability. For Mammography, 17 to 20 KeV is best. Unlike conventional mammography, the tube voltage is driven about 4 times the k alpha line, or 66 KV, to achieve the best efficiency in exciting the k alpha line. Regulation of high voltage is required to 0.01% because of the high sensitivity to k alpha line intensity. Radiation 16 from X-ray tube 14 has a solid angle in the order +-2.5 degrees in one plane and +-6 degrees in the other plane falls on the crystal monochromator array C M . The radiation at the Bragg angle corresponding to the X-ray energy of interest is Brag reflected and refocuses to a line and passes through slit aperture stop S. This slit aperture stop S shields all other scatter radiation from the patient. The beam then again expands to a 3 cm by 24 cm field at breast platform P. This field is scanned either continuously or in steps to cover a 18 cm by 24 cm field size. The beam after passing through the patient falls on analyzer crystal array C A , is Bragg reflected from this array and then falls on tiled array ccd detector D. Scanning mechanism M is comprised of three ball screws/motors 18, and two guide cylinders 20 and accompanying roller bearings. Independent control of these stepper motors allows either a linear scan or a rotational scan about the slit center to be accomplished. A rotational scan enables one to either do time delay integration in a continuous scan mode, or stitching image slices together in a step scan mode without geometric aberrations, as shown in FIG. 3. A linear scan allows for deconvolution of three dimensional data by virtue of differential velocity, as shown in FIG. 4. The unique line source typical of this diffraction system is ideal for this approach to three dimensional imaging. The crystal array platforms are optically aligned by six piezoelectric micropositioners Z 1 -Z 6 on each platform, as shown in FIG. 5. The six degrees of freedom are provided in accordance with the vectors adjacent each of the micropositioners Z 1 -Z 6 This much is shown in conjunction with the table of FIG. 6. Referring to the table of FIG. 6, movement of the crystal can be seen to include X, Y, Z, A, B, and e (that is Alpha, Beta and Theta). Where a positive value appears, piezomicropositioners increase in dimension; where a negative value appears, piezomicropositioners decrease in dimension. TABLE I______________________________________FIG. 8______________________________________Monochronometer Parameters R1 = 1,000000 R2 = 2,000000 R.sub.T = 40,000000 R.sub.T = 40,000000 A = 68,000000 B = 73,000000 C = 2,500000 G = 0,020000 R1 Angles D = 79,000000 E = 79,000000 F = 79,000000 H = 79,003091 I = 79,004261 J = 79,002345 R1 Differences D-D2 = 0,000000 E-E2 = 0,000004 F-F2 = 0,000003 H-H2 = 0,000014 I-I2 = 0,000034 J-J2 = 0.000012 R0 Angles D = 79,002343 E = 79,002770 F = 79,002023 H = 79,005434 I = 79,007031 J = 79,004368 R0 Differences D-D2 = 0,001269 E-E2 = 0.000316 F-F2 = 0.001647 H-H2 = 0.001285 I-12 = 0.000354 J-J2 = 0.001632ANALYZER Parameters R1 = 1,000000 R2 = 2,000000 R.sub.T = 40,000000 R.sub.T = 40,000000 A2 = 68,000000 B2 = 79,000000 X = 0,000000 L1 = 0,555930 R1 Angles D2 = 79,000000 E2 = 79,000004 F2 = 78,999997 H2 = 79,003076 I2 = 79,004227 J2 = 79,002357 R0 Angeles D2 = 79,001074 E2 = 79,002454 F2 = 79,000376 H2 = 79,004149 I2 = 79,006677 J2 = 79,002736______________________________________ The Bragg angle of each individual crystal is fine tuned by applying a load to flexible diaphragm 22 under third ball support 24 of the mount of crystal C as shown in FIG. 7. This load is generated with screw 26 and larger flexible diaphragm 28 to decrease the sensitivity of the adjustment. As shown in FIG. 2, diffraction cage 30 supports the array platform in a rigid manner by virtue of its rigid structural design both in torsion and bending, and is vibration isolated from the machine by six sets of air bearing supports 32. These air bearings provide isolation with a minimum of displacement so that the relationship to the X-ray tube and patient is preserved. Referring to FIG. 13A and 13B, tiled array ccd detector D is a tiled array of eight 512 by 512 CCD units, covering a 3 cm by 24 cm field, all cooled to -20 degrees C with Peltier modules 34 for minimum noise. Conventional heat sinks and tapered fiber optics are shown in FIGS. 14A and 14B, but will not be further discussed here. Segmenting the detector in this manner allows a variety of problems to be solved. First, it will be observed that the detector can be curved according to the distance from the source to minimize geometric aberrations in image reconstruction. In addition, each unit can have a separate driver and converter to maximize the data rate transfer (30 megabits in 3 seconds). Separate real time x-ray photodiode detector elements 36 are located in all quadrants between the CCDs in the array to allow CCD integration time to be established prior to full exposure. Tiled array ccd detector D can be replaced with a film cartridge as an alternative. The film must be driven at a rate that corresponds the velocity of the image as the scan is executed only a rotational scan without geometric aberration is done. In-depth Description of X-ray Optics FIG. 8 and 9 show the detail diffraction path ray trace for this system. The objective met by the design is the utilization of as much of the emitted X-ray energy from the source at the wavelength of interest as possible. This objective is met by both a large cone of emitted X-rays being utilized (low F number concept in optics) as well as by utilization of the emission from the entire surface of the finite size source target area. The beam angle and source size is simulated in this ray trace. Electrons e - are hitting an X-ray generating source such as a rotating annode target. The medial portion of the source lies on the Roland circle (diffraction radius R 1 ). (See also FIG. 8). Prior art in X-ray tube design provides for angular projection target T where the projected beam is a small symmetrical spot, even if electron beam E hitting the target is long and narrow. This is done to distribute the heat load of the electron beam. In utilizing such a source in this design, the target is oriented as show to minimize aberrations in meeting the above criteria. The basic prior art diffraction principal of this focusing diffraction monochromator design is the Johansson geometry as shown in FIG. 10, where the curvature of the crystal structure is twice the curvature of the physical surface of the crystal. This Rowland geometry provides perfect theoretical focusing for an infinitely small source, and a large angular cone of emitted rays. The described crystal arrays are in fact emulating the pure Johannson geometry, and are arrays only for the purpose of ease of manufacture. Each successive row in each array has an increasing asymmetry in crystal plane orientation in order to emulate a larger single crystal Johannson monochromator. As can be seen, diffraction radius R 1 and crystal matrix radius R 2 appear to enable source 40 to focus from all points on the surface to focal point 42. The disclosed mirroring diffraction system shown in FIG. 8 includes two Johansson type arrays where the output of crystal monochromator array C M is the input to analyzer crystal array C A . Ideally all rays Bragg reflect through both crystal monochromator array C M and analyzer crystal array C A , but can only do so if the diffraction ray trace shows that the Bragg angle is identical on both crystals, or at least within a small percentage of the characteristic rocking curve for the crystal material in use. The disclosed mirroring diffraction system achieves a very high throughput of rays (identical Bragg angle on both crystals) emitted over the entire surface of the 0.1 mm projected source size, equivalent to the bandpass for the entire K alpha line and for as large a beam cone as geometrically possible for a given Bragg angle. This is accomplished by selecting the best relative orientation of the two crystal arrays, the best ratio of Rowland circle diameter for the two arrays, and the best asymmetry for the two crystal arrays, i.e. the best combination of the above variables. The behavior the system becomes dispersive, whereas a single Johansson crystal monochromator is otherwise considered non-dispersive, i.e. only perfect focusing for an infinitely small source size. TABLE I______________________________________FIG. 8______________________________________Monochronometer Parameters R1 = 1,000000 R2 = 2,000000 R3 = 40,000000 R4 = 40,000000 A = 68,000000 B = 76,000000 C = 2,500000 G = 0,004000 R1 Angles D = 79,000000 E = 79,000000 F = 79,000000 H = 79,003091 I = 79,004261 J = 79,002345 R1 Differences D-D2 = 0,000000 E-E2 = 0,000004 F-F2 = 0,000003 H-H2 = 0,000014 I-I2 = 0,000034 J-J2 = 0.000012 R0 Angles D = 79,002343 E = 79,002770 F = 79,002023 H = 79,005434 I = 79,007031 J = 79,004368 R0 Differences D-D2 = 0,000772 E-E2 = 0.000537 F-F2 = 0.001242 H-H2 = 0.000781 I-12 = 0.000537 J-J2 = 0.001243ANALYZER Parameters R1 = 1,000000 R2 = 2,000000 R3 = 40,000000 R4 = 40,000000 A2 = 68,000000 B2 = 79,000000 X = 0,000000 L1 = 0,555930 R1 Angles D2 = 79,000000 E2 = 79,000004 F2 = 78,999997 H2 = 79,003076 I2 = 79,004227 J2 = 79,002357 R0 Angeles D2 = 79,001074 E2 = 79,002454 F2 = 79,000376 H2 = 79,004149 I2 = 79,006677 J2 = 79,002736______________________________________ Referring exclusively to Table I, R1 through R4 for each monochromator define the toroidal curvature of both the crystal structure (bending) and the physical surface (machining). Angle A controls the Bragg angle, or energy, angle B controls the symmetry of the monochromator, and C is the width of the beam cone in plane. Angle G defines the divergence of the beam out of the plane, L1 is the distance between the monochromators, and X1 is the angle of rotation between the monochromators. Angles D through J are the Bragg angles of the six rays defining the beam cone, with D being the central ray. The finite source size is simulated by R0, where R1-R0 is the source size. It can be seen that by virtue of "R0 angles" that the finite source size results in a change in angle of 0.002 to 0.003 degrees, an acceptable percentage of the 0.012 K alpha line width. It can also be seen that the Bragg angle differences between the two monochromators are acceptable as compared to the narrowest rocking curve of lithium flouride of 0.028 degree. The "R1 differences" are less that 20 millions, as expected, and the "R0 differences" associated with the finite source size are less than 0.001°, comparable to the rocking curve, and a small fraction of the associated shift in overall Bragg angle of 0.002 degrees. The previously mentioned orientation of the source results in the effective projected size of the source being smaller for the F ray, which equalizes the R0 differences. In the case of silicon monochronometers, with a narrow rocking curve (ie. 0.0004°) the R 0 differences can be further reduced by optimizing the above stated optical parameters for each row of crystals in the array separately. In this manner R 0 differences can be less than 0.0002°. In plan as shown in FIG. 9, the beam cone angle is +-6 degrees and all ray traces through this plain are identical and without aberration, as the crystals in the array are sector shaped and have a toroidal curvature where the curvature in this plane (toric radius R T ) corresponds to the distance from the source, and the curvature in the other plane is simply the Rowland circle. In-depth Description of Imaging Process The imaging principle of this system is that any object placed in the beam between the two monochromator crystal arrays will cause some photons to be absorbed, scattered, and refracted as shown in FIG. 11. This should be distinguished from conventional X-ray imaging based only on photons being absorbed. This system images by virtue of all these processes as any angle change associated with scattering or refraction changes the Bragg angle on the second monochromator. The ray is then not Bragg reflected and does not reach the detector. Not only does this approach eliminate the blurring effect of Compton scattering in the object without the use of a grid, but actually allows imaging by virtue of the scattering phenomenon. Experimental data suggests that at cell/tissue boundaries refractive and scatter effects allow imaging of objects where density variation are negligible, i.e. tumors. The degree that the imaging system has sensitivity to refractive effects is directly related to the monochromator crystal material and its associated rocking curve width. Silicon for example has a 1.6 second rocking curve width, whereas lithium fluoride has one 60 times higher as shown in FIG. 12, partly by virtue of its mosaic crystal structure. Other materials that would commonly be considered are germanium, and quartz. The trade-off in higher refractive sensitivity with a narrower rocking curve width is overall image content, beam intensity, and fabrication tolerances. The choice of crystal material also limits the energy that can be used, as the only lithium fluoride reflecting off of the 420 plane will allow a reasonably large Bragg angles at higher energies, i.e. 60 Kev. In fact, depending on the dominant mechanism in the image detail of the object of interest, the ideal effective rocking curve may be larger than what is inherent the crystal of choice. In this case the analyzer crystal can be wobbled; over a larger range during the integration period of the detector, effecting a wider rocking curve. The choice of X-ray energy allows the absorptive features to be minimized as compared to scatter or refractive. For mammography 17 KeV allows a balance in all imaging mechanisms, whereas 60 KeV would allow absorption features to be minimized. The nature of the imperfections in the optics in this system require a normalization to be done to correct for variation in intensity in the field, particularly at crystal boundaries, where different Bragg reflection efficiencies would be very noticeable. This correction is less necessary in the time delay integration (TDI) approach either with film or digital, because of the sector shaped overlapping crystals and the averaging process inherent in TDI. In the case of image stitching/step scanning, intensity values must be normalized based on an image without an object. This can be done easily by the computer. Detailed description of scanning and detection The preferred embodiment for the detector is shown in FIG. 13A, 13B, and 19, which includes a prior art tiled array Scintillator\fiber-optic\CCD detectors, but so configured for specific unique benefits. This approach is enhanced for this application by using boundary photodiode intensity detector to establish an initial intensity measurement to enable the integration time for each of the 10 CCD modules/drivers to be established independently. In part, the CCD elements are sized to allow the data to be dumped within the time defined for the scan without readout noise dominating total noise. This embodiment will typically also have a dedicated DSP associated with each CCD array to facilitate rapid processing/deconvolution of the data in parallel. The nature of the mammography application is such that the attenuation of X-rays in the patient range over several orders of magnitude depending on the location on the breast, particularly since skin line viewing is desired. The dynamic range of the CCD itself is limited to about 100, so in order to accommodate the attenuation and still have sufficient density resolution, the integration time for the CCD must be adjusted in a real time manner based on the highest intensity measured at the four corners of each CCD with these discreet photodiode detectors. In part, the CCD elements are sized so that a limited variation in intensity can be expected over the given area, again by virtue of patient cross section. As discussed above, the detector segments are additionally sized so that it emulates toric radius R T . In order to obtain geometric aberration free scans, the surface of detection must lie on the surface of a toroid defined by the distance to the source in one plane, and by the distance to the slit in the other plane. This second criteria is inherent in the rotational scan about the slit, as shown in FIG. 3. Aberration free geometry insures that a time delay integration approach for continuous scanning, or a slice image stitch protocol for step scanning can be used with no image artifacts. The sector shape of the crystals in the arrays allow for the full coverage of the field, even with a significant inactive boundary on the crystals as shown in FIG. 9, although intensity correction must be applied to the part of the image where the crystal boundary exists. The linear scan process shown in FIG. 4 in a continuous scan mode with discrete pixel by pixel integration allows a three dimensional image to be deconvoluted. Although there are a variety of ways of deconvoluting in the prior art, the preferred approach is to view the situation as one of differential velocity, where features at different heights in the patient have different velocities in the image during a scan of constant mechanical velocity. Because of the unique line source nature of the optics, the object can be located where significant differences in velocity exist between the top and bottom of the patient, effecting better deconvolution as shown in FIG. 14. As the object is moved closer to the line source (a), as compared to position (b), the beam becomes more narrow, in effect resulting in magnification of the image on tiled array ccd detectory D, increasing system resolution. There is no patient dose penalty for this magnification. Although the beam intensity is much higher near the line source, the time the patient is exposed is less as the system scans, as the beam is also narrower. It can be seen at distance d 1 -a portion of specimen Q 1 closer to the source--has a smaller velocity v 1 . It can be seen at distance d 2 --a portion of the specimen Q 2 further from the source--has a larger velocity v 2 . One embodiment of this deconvolution allows one to define a relevant number of depth slices in the patient, i.e. 10 to 50, and do a factor analysis/singular value decomposition, with the initial value at any depth being define by a conventional time delay integration based on the image velocity at that depth. An added feature of three dimensional imaging done in this manner is that the quality of the data in a specific volume of interest is significantly enhanced. Not only is there no overlying image features that may obscure the image in the volume of interest, but noise factors fall out of the image by virtue of the SVD algorithm. An additional enhancement to image quality and three dimensional imaging is the ability to magnify in one dimension the image to increase resolution without additional image degradation resulting from Compton scatter typical in magnification geometries on conventional systems. In-depth Description of Crystal Fabrication Methods The monochromators in this system are arrays for the purpose of facilitating their fabrication, both from the standpoint of yield and stress reduction, as will be described and for the purpose of optimizing each row separtely if necessary. The design of these Johansson crystals is show in FIG. 17A and 17B, where crystal C is bonded to base B with either glue, a diffusion bond, or other bonding intermediate layer. It is necessary to match the thermal expansion coefficient between the base and the crystal so that the differential expansion does not distort the curvature. The preferred embodiment for silicon is to also make the base out of silicon, and anodically bond the two together with a sputtered glass interface. This method requires only moderate temperatures. The physical tolerance for fabricating the crystals is exceeding tight, particularly when the final tolerances are a result of machining, bending, and bonding the crystal to the mount. The method that has been discovered to provide the necessary tolerances in a toroidally curved and bent crystal is a triple diamond point lathe machining process, with an intermediate bonding process. The unique aspect in particular to this approach is that a toroidal shape can be obtained with stresses in the crystal that are little higher than what would be typical of a cylindrically bent crystal. Stress in cylindrically bent crystals are by prior art demonstrated to be acceptable, even for silicon, both in fracture limit and degradation of reflectivity by virtue on crystal strain. Prior art in forming toroidal curvature has limited their use because of this problem. FIG. 15 shows the basic technique for cutting the toroid shape on a diamond turning lathe. The crystal is located at toric radius RT on turn table 44. Location is at an equivalent distance to the position the crystal with respect to the source in the X-ray system. The Rowland circle related diameter (diffraction radius R 1 ) is then cut by virtue of NC programming to control cutting head 46 and diamond tool 48. This process applies to the mount, the back of the crystal before mounting, and the front of the crystal after mounting, generating the shapes shown in FIGS. 16, 17, and 18. The resulting final assembly as shown in FIG. 18A and 18B has a crystal of constant thickness, and low residual stress, as the bonding of the convex toroidal shape of the back of the crystal (FIG. 17A and 17B) to the concaved toroidal mount (FIG. 16A, 16B, and 16C) induces minimum stress. The parameters of crystal mount construction are as follows: TABLE 2______________________________________FIG. 17A AND B "RO"P/N "A" "B" "C" LOCATION 1.003 0.76!______________________________________10 - 8 1 10 1.20 MONOCROMATOR 19.09720001 250 27.9! 30.5! ROW 1 485.06!10 - 10 1 20 1.30 MONOCROMATOR 20.85720002 810 30.5! 32.8! ROW 2 529.77!10 - 13 1 30 1.39 MONOCROMATOR 22.62320003 370 32.8! 35.3! ROW 3 574.62!10 - 15 1 39 1.48 MONOCROMATOR 24.39020004 930 35.3! 37.6! ROW 4 619.50!10 - -3 2 28 2.37 ANALYZER ROW 1 41.06620005 75 57.8! 60.2! 1043.08!10 - -1 2 37 2.46 ANALYZER ROW 2 42.80220006 190 60.2! 62.5! 1087.17!10 - 1 2 46 2.56 ANALYZER ROW 3 44.52220007 370 62.5! 65.0! 1130.86!10 - 3 3 56 2.66 ANALYZER ROW 4 46.22220008 930 65.0! 67.6! 1174.04!______________________________________ The parameters of crystal construction are as follows: TABLE 3______________________________________FIG. 16A B AND CP/N "A" "B" "C" "RO"______________________________________11 - 1 040 1,136 750 19.05! 19.097 485.06!20001 26.42! 28.85!11 - 1 136 1,234 750 19.05! 20.857 529.77!20002 28.65! 31.34!11 - 1 234 1,328 1,000 25.40! 22.623 574.62!20003 31.34! 33.75!11 - 1 328 1,422 1,000 25.40! 24.390 619.50!20004 33.75! 36.12!11 - 2 216 2,310 1,000 25.40! 41.06620005 56.29! 58.67! 1043.08!11 - 2 310 2,404 1,000 25.40! 42.80220006 58.67! 61.06! 1087.17!11 - 2 404 2,498 1,000 25.40! 44.52220007 61.06! 63.45! 1130.86!11 - 2 498 2,592 1,000 67.6! 46.22220008 63.45! 65.84! 1174.04!______________________________________ The parameters of figure to the diffracting surface of the chips are as follows: TABLE 4______________________________________FIG. 18BP/N 1 CRYSTAL 2 MOUNT "T"______________________________________12 - 20001 10 - 20001 11 - 20001 19.097 485.06!12 - 20002 10 - 20002 11 - 20002 20.857 529.77!12 - 20003 10 - 20003 11 - 20003 22.623 574.62!12 - 20004 10 - 20004 11 - 20004 24.390 619.50!12 - 20005 10 - 20005 11 - 20005 41.066 1043.08!12 - 20006 10 - 20006 11 - 20006 42.802 1087.17!12 - 20007 10 - 20007 11 - 20007 44.522 1130.86!12 - 20008 10 - 20008 11 - 20008 46.222 1174.04!______________________________________ In-depth Description of System Operation Referring to FIG. 19, the sub-systems of the image processing can be described. X-ray tube 14 is shown with standard driving subsystems. Further, conventional scan and machine controls 52 provide both scan and platform positioning and conventional breast compression. Machine function is preprogrammed in alignment, position, and exposure controls 54. Tiled array ccd detector D is shown with output to conventional drivers 56. Thereafter, conversion at analog/digital converters 58 with output to digital signal processor (DSP) 60. Final output is to buffer memory 62 with a conventional computer processor image generating processing following in computer array 64. Building upon the preceding subsystems descriptions, the overall system functionality is represented in FIG. 19. Upon power-up, the instrument executes a diagnostic and alignment routine to insure proper operation. FIG. 20 shows the steps in this process. Five degrees of freedom on the monochromator platform, four degrees on the analyzer and three degrees on the slit are adjusted. The algorithms uniquely combined several degrees of freedom at one time to effect independent control of the Bragg reflection, k alpha line centering, longitudinal field symmetry, left lateral field symmetry, and right field lateral symmetry. Six intensity detectors in both the patient plane and the detector plane are use to detect the field intensities for both the monochromator and analyzer adjustment. After passing alignment standards, the four alignment detectors and the discrete boundary detectors in the CCD array remain working as diagnostic monitors to insure safety and performance. Any fault results in shut down of the system. Before an exposure, the operator defines the following parameters: Field size Field position Compression force Scan type Step scan TDI scan Three dimensional scan Real time Compression command Exposure command During an exposure, control commands either a high pulsed X-ray tube current for a step scan, or a medium constant current for a TDI scan. In either case the current is defined by the maximum heat load limit of the X-ray tube. In the case of the step scan, the pulse duration is based on the lowest measured intensity of the boundary detectors that results in more than the minimum number of photon counts with the largest integration period, i.e. 200 ms. After exposure, the system then has 300 ms to transfer the data, and simultaneously move to the next position. In the case of the TDI or 3D scan, the mechanical scan rate is adjusted based on the lowest boundary intensity detector. The X-ray tube is operating at a constant current that is the maximum allowed for a period to complete the entire scan, i.e. 2 to 3 seconds. Both for a constant rate scan or a step scan, prior art PDI algorithms can be used to control the motors for rapid, smooth, accurate positioning with no overshoot or droop. Alternate Embodiments and Applications One possible embodiment is to incorporate a two dimensional focusing embodiment with a monochromatic point source. FIG. 21 shows a two dimensional implementation of focusing. This approach using two toroidally curved monochromators at 90 degrees (crystal monochromator array C M1 and crystal monochromator array C M2 to avoid confusion, actual drawing of the crystals has been omitted!) allows the focusing of all rays Bragg reflecting at the same energy to be focused to point source S 1 , rather than the previously illustrated slit aperture stop S. A similar configuration can be used for the analyzer. The benefits of this two dimensional focusing embodiment are for a true X-ray microscope with the same imaging capability inherent in the technique, and for real time imaging systems, i.e. fluoroscopy where scanning in one dimension is contrary to the real time concept. A dramatic dose reduction would be associated with a monochromatic point source for fluoroscopy. An alternate embodiment of a staggered array is shown in FIGS. 22A and 22B. These figures show respectively a plan view schmatic and a schematic in the direction of scan. This demonstrates how a staggered array of high aspect ratio multi-line detectors (not unlike that shown in some prior art embodiment) used in conjunction with slot scanning and TDI data acquisition techniques. (It is noted that the presence of crystal monochromator array C M and analyzer crystal array C A distinguish this from the prior art.) It is to be noted, that analyzer crystal array C A and crystal monochromator array C M can have a staggered construction just as the known and illustrated detectors in FIG. 22B have a staggered construction. Information that is "lost" in any one image will be acquired during total scan of the instrument. The benefit of this approach is a much lower cost system, but it is dependent on sufficient intensity to maintain low exposure times with a small field of detection. The lower cost is associated with facilitating fabrication of the semiconductor elements, particularly for direct conversion approaches. The diffraction crystals can similarly be made partial Staggered arrays with a significant cost reduction for these components. With reference to FIGS. 23A and 23B, a transmission analyzer crystal C A1 is illustrated. The preferred embodiment uses a Bragg reflection analyzer (analyzer crystal array C A ) and monochromator (crystal monochromator array C M ) . A curved Laue transmission crystal of prior art design has been used as a monochromator before the patient, without the use of an analyzer. In fact, such a curved Laue transmission monochromator C M1 can be used for the analyzer as shown in FIG. 23A, or both the analyzer C A1 and monochromator C M1 , as shown in FIG. 24, to achieve the same imaging mechanisms as described in the preferred embodiment. An off axis scattering configuration can be seen with respect to FIG. 24. As the primary imaging mode in some situations may be scattering, the orientation of the analyzer beam direction may be significantly off the axis of the monochromator beam as shown in FIG. 24, and form a higher contrast image by virtue of detecting scattered radiation, rather than be virtue of detecting the unscattered beam with reduced intensities where scatter is present. A secondary scatter slit is illustrated in FIG. 25. To further shield the detector from all radiation scattered by the analyzer, tiled array ccd detectory D can be located down stream from additional slit aperture stop S 1 , located at the focal point of the analyzer crystal array C A , as shown in FIG. 25. In some applications this additional slit may improve image quality, depending on the dominant imaging mechanisms. Alternately, TDI modification for eliminating curvature can be utilized. As an alternative to curvature of the detector in the plane normal to the scan direction as shown in FIG. 13A and 13B, the TDI integration times can be modified along the length of the detector based on the difference in distance from the source, and the corresponding difference in image velocity during the scan. It will be realized that this disclosure includes considerable oncology potential. To accompany the ability to detect microtumors less than one millimeter in size, X-ray diffraction optics allow an array of orthogonal doublets as described above to focus X-rays for therapeutic purposes with a dose to a one millimeter tumor at a 4 cm depth on the order of 100 times higher than any surrounding tissue. To understand a single doublet, the reader is reminded that this construction has been previously set forth in FIG. 21. FIG. 27A illustrates the ray trace of four such doublets. A combined system could encompass an imaging system and a therapeutic system that operate simultaneously, as they could operate at different wavelengths and not interfere.

An X-ray imaging system utilizing diffractive X-ray examination is utilized which includes an interrogating X-ray path from a conventional broad band X-ray source having a standard emission point. X-rays from the X-ray source impinge on a toric monochronometer having monochromatic Bragg X-ray diffraction occurring resulting in monochromatic X-ray diffraction. X-rays exiting the slit aperture stop expand and form a scanning beam and pass through the specimen (usually soft tissue) being examined. In passing through the specimen, the X-rays receive image information by absorption, critical angle scattering, and, refraction, dependent upon the specimen, structure. The X-rays are then incident on a toric detection crystal where monochromatic Bragg X-ray diffraction again occurs leaving the image revealed by absorption, critical angle scattering, and, refraction which occurred in the specimen. The diffracted monochromatic X-rays with the specimen induced images are then directed to an X-ray detector for image processing. The preferred embodiment includes a mammography apparatus in which each mammary is swept and scanned by an oblong beam (in the order of 3×24 centimeters) with scan direction between nipple and chest. Due to beam expansion from the slit aperture stop to the toric detection crystal, mammary tissue at varied elevations from the slit aperture stop provides differing relative motion for mammary tissue at each elevation. Image processing actually segregates the soft tissue images by imaging planes taken normal to the mean path of the expanding beam. To enable construction of virtually any required diffracting surface, a technique of segmenting and bending diffracting crystals is disclosed.

With respect to the International Application as published on May 15, 1997: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to structures that can be incorporated into an electrical connector in order to mechanically connect the connector to a complementary component. The structure is particularly applicable to board-to-board connectors, but not limited thereto. 2. Summary of the Prior Art U.S. Pat. No. 5,324,206 discloses an electrical connector comprising a pressure table floatably coupled to the connector housing and resiliently biased therefrom. This pressure table is operative to bias a flexible circuit against the surface of a mating circuit board. In electrical connectors, it is necessary to establish not only an electrical connection between the complementary contacts which may be housed in a terminal block or upon a printed circuit board; but also, to interconnect mechanically the mating connector components to ensure that the electrical connection is not defeated. This has been accomplished in the prior art in a number of manners, such as fasteners similar to screws or clips, resilient latch arms on one of the connectors that cooperate with lugs on the other connector, or external devices that function to hold the two together. These structures typically work well where there is a fairly large range of tolerance with respect to where the electrical interconnection may occur over the distance of mating the two connector components together. This would be the case where one of the contacts is a pin contact an the other contact is a receptacle contact having spring arms to form a wiping interconnection with the pin, as anywhere along the pin would form a satisfactory connection. In addition, an interconnection of this type requires that a fairly large load must be brought to bear on the mating connector in order to engage whatever latching structure is being used. These two considerations create a problem where there is either not enough linear travel available to establish the desired interconnection or the mating components are not capable of bearing the amount of force necessary to establish the interconnection. An example might be where a daughter card is to be mated with a mother board and for whatever reason the standard edge card connector is not satisfactory. These short comings are met by providing an electrical connector according to claim 1 for mating with a complementary component having a mating face and a plurality of complementary contact members. An embodiment of the connector comprising a terminal block having a front face and a plurality of contact receiving regions therein for receiving contacts that mate with the complementary contacts, a housing block wherein the terminal block is disposed and a connector coupler operatively associated with said terminal block for engaging an anchor fixed on the complementary component in order to mechanically couple the connector and complementary component; the connector being characterized in that: the connector is mounted upon the board such that the structure may float in the direction of mating and the terminal block is resiliently biased by a resilient member relative the housing bock such that when the connector coupler is engaged with the anchor, the front face of the terminal block together with the mating face for the complementary component. This makes this connector coupler device especially useful where it is desired to form the interconnection between a contact pad and a spring contact, such as that used in an interposer. This feature further isolates those forces necessary to hold the electrical connector with the complementary component from the forces associated with the contacting members. Finally, a connector of this type is especially useful for board-to-board interconnections where contact pads may be used instead of contact pins. For example, in U.S. Pat. No. 4,895,521 (incorporated herein by reference for all purposes) a co-axial connection module is disclosed that is particularly suite for board interfaces, especially one disposed on a multi-level board. In this case a signal pad is surrounded by a ground pad such that complete shielding is offered at the board. The module includes a conductive outer sleeve, a dielectric support element and a contact element having a spring portion extending therefrom. The conductive sleeve being configured to engage the ground pad and the spring portion to abut the signal pad such that a true co-axial interconnection is formed. By incorporating modules of this type into a connector having the aforedescribed structure, dimensional variations can be accommodated, mating force requirements reduced and any mechanical set of the spring member minimized as the loading thereof is controlled. SUMMARY OF THE INVENTION It is an advantage of this invention that the connector coupler may be engaged to the anchor as the connector and complementary component are being mated so that the spring member establishes the mating forces therebetween. It is another advantage of this invention that by having the contact members of the complementary component a said distance from the mating force and the contacts of the connector a said distance from the front face, electrical connection may be assured in a reliable manner as the mating face will abut the front face, thereby fixing the distance between contacts also. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an upper rear perspective view of the present invention incorporated into a board-to-board interconnection system; FIG. 2 is a conceptional schematic view of the workings of a board-to-board connector of FIG. 1 showing a pre-mating "cocked" condition; FIG. 3 is a conceptual schematic view similar to FIG. 2 showing the first mated position; FIG. 4 is a conceptual schematic view similar to FIG. 3 showing the fully mated position; FIG. 5 is a conceptual schematic view showing initial de-mating; FIG. 6 is a conceptual schematic view showing the first de-mated position that corresponds to the mated condition of FIG. 3; FIG. 7 is a conceptual schematic view showing the fully de-mated position that corresponds to the pre-mated or "cocked" condition of FIG. 2; FIG. 8 is a conceptual schematic view showing attempted mating of the connector when not in the pre-mated or "cocked" condition; FIG. 9 is a side cross-sectional view corresponding to FIG. 2 showing the electrical connectors of FIG. 1 ready for attachment; FIG. 10 is a side cross-sectional view corresponding to FIG. 3 showing the connector of FIG. 9 initially coupled to anchors on the mating component; FIG. 11 is a side cross-sectional view corresponding to FIG. 4 showing the connector engaged as in FIG. 1; FIG. 12 is a side cross-sectional view corresponding to FIG. 5 showing the connector being disengaged from the anchors on the board; FIG. 13 is a corresponding side cross-sectional view as the anchors disengage from the connector coupling members; and, FIG. 14 shows a side cross-sectional view showing attempted mating where the connector couplers are not in a cocked position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference first to FIG. 1, a board-to-board interconnection is shown generally at 1. The board-to-board interconnection 1 includes a motherboard 2 and a daughter card 4. The daughtercard 4 has upper and lower surfaces 6,8 with electrical connectors 10 that incorporate the present invention therein. It is important to note that the invention is being described with reference to a board-to-board connection system 1 where it is especially advantageous but the invention is not limited to such applications. The motherboard 2 is a complementary component having a mating face 12 thereupon. As would be typical in printed circuit board construction, the motherboard 2 would include circuit traces and components upon the mating face 12 and a plurality of complementary contact members (not shown) forming an electrical interconnection with the mating component or daughter card 4. The motherboard 2 further includes anchors 14 fixed to and extending therefrom. With reference still to FIG. 1, the daughtercard 4 carries a pair of connectors 10 that are interconnected on opposite faces 6,8 thereof. In the embodiment shown, each connector 10 is made up of a base plate 16 that lies fixed against the corresponding face 6,8 and includes a plurality of openings 18 for providing access to the contact members (not shown) disposed upon the daughter card 4 by flexible conductor members 20. The conductor members 20 extend from the base plate 16 into a housing block 22 where they are connected to contact modules (not shown). These contact modules may be advantageously formed as interposer-style contacts that rely on a normal force established perpendicularly to the corresponding mating faces 12,24 to establish an electrical interconnection such as those disclosed in U.S. Pat. No. 4,895,521. Another example of an acceptable contact is disclosed in U.S. Pat. No. 5,228,861. The housing block 22 contains a resiliently biased and floating terminal block 23 that has a front face 24 that can be seen abutting the mating face 12 of the motherboard 2. At each end 26,28 of the housing block 22 are connector couplers 30. The connector couplers 30 will be described in greater detail below. The housing block 22 is slidably affixed to the base 16 by way of complementary dove-tail structure including a male dove-tail 32 as part of the base 16 and a female dove-tail slot 34 as part of the housing block 22. This provides that the housing block 22 with float along the dove-tail strucure 32,34. It may be possible to use other mechanical couplings as an alternative to the dove-tail that limit the motion therebetween to a single degree of freedom. Additionally, the terminal block 23 may be similarly mounted to the base 16 (free floating) upon the dove-tail 32 or coupled only to the housing block 22 through dove-tails formed in the sidewalls thereof. The terminal block 23 has a releasable latch mechanism between the housing block 22 and the terminal block 23 such that they are selectively coupled. Furthermore, a resilient member or spring acts between the block 22,23 to bias the terminal block 23 from the housing block 22 as will be described below. Note, the amount of float of either block 22,23 may be limited by stop or latch structure (not shown) therebetween. The invention is best described with reference to the conceptual schematic views shown in FIGS. 2-8, where FIGS. 2-5 show the mating sequence, FIGS. 5-7 show the demating sequence and FIG. 8 shows a fail safe feature where the connector 10 is prevented from mating unless in a "cocked" position. In these Figures, the representations corresponding to the features described above are numbered in the 100 series in a corresponding manner and the conceptual features, separately, are all within the basic mechanical arts and may be achieved in various ways. With reference now to FIG. 2, the connector 110 is mounted upon the daughter card 104 by the base plate 116 with the terminal block 122 disposed within the housing block 22 such that it is free to move longitudinally relative thereto as established by the dove-tails 40. The housing block 22 and the terminal block 23 are slidably coupled relative each other and to the base 116, for example by way of the dove-tails 132 and 140, such that the housing block 122 is free to move axially upon the daughtercard 104 and the terminal block 123 is free to move axially relative the housing block 122 in the direction of insertion F. The base 116 further includes stops 143 that are used to limit the displacement of the terminal block 123 as will be described below. The terminal block 123 and the housing block 122 are joined together by a resilient member 144 and at a releasable latching mechanism consisting of a latch arm 145 and a catch 146 affixed to the terminal block 122 and the housing block 123 respectively. The releasable latching structure may take on any number of forms as are well known in the mechanical arts. Additionally, a connector coupler 130 is attached to the housing block 122 for engaging the anchor 114 of the mother board 102. With the releasable latch mechanism positioned such that the latch arm 145 is retained by the catch 146, as shown in FIG. 2, the daughter card 104 is inserted in the direction of force F. With reference now to FIG. 3, insertion in the direction force F continues until the coupling member 130 engages the anchor 114. At this engagement point, the face 124 of the terminal block 123 is separated from the face 112 of the motherboard 102. As a result of the stop surface 143 upon the base 116 and the coupled releasable latch mechanism 145,146 sufficient force may be generated to engage the coupling member 130 with the anchor 114. As the coupling member 130 is relatively stiffly joined to the housing block 122, it is not possible for additional force in the direction of arrow F to bring the mating faces 124,112 into engagement. With reference now to FIG. 4, once the connector is positioned as in FIG. 3, the releasable latch members 145,146 are disengaged, for example by a mechanical feature that separates the coupling, such that the terminal block 123 is disposed such that the mating faces 124,112 are abutting as a result of the resilient member 144. Additionally, a certain amount of manufacturing tolerances in the positioning and the sizes of the components may be accommodated by the variation A. Within this region, it is possible for the resilient member 144 to exert roughly the same amount of force at the mating face interface 124,112. Additionally, in this configuration, there is no force link between the terminal block 123 and the daughter board 104 such that the terminal block 123 is essentially free floating relative thereto and biased against the mother board 102 by the spring force of the resilient member 144 that is coupled to the housing block 122 which is anchored to the mother board 102 by coupling member 130. With respect now to FIGS. 5-7, the demating sequence will be described. With reference first to FIG. 5, upon the exertion of a removal force F', the daughter card 4 is withdrawn such that the base unit 116 moves relative the terminal block 123 until the front step 143 becomes engaged therewith. Additional displacement in the withdrawal direction F' results in the base member 116 carrying the terminal block 123 rearward until the releasable latch members 145,146 engage (FIG. 6). Upon further extraction in the withdrawal direction F', the coupling member 130 disengages from the anchor 114. In this position, the connector 10 would be ready for mating on the next insertion. With reference now to FIG. 8, if the "cocked" position of FIG. 7 and FIG. 2 is not established be for mating, the condition shown in FIG. 8 will occur. The lack of engagement between the releasing latch mechanism 145,146 prevents the coupling member 130 from engaging the anchor 114 as the housing block 122 will travel rearward with the terminal block 123 in response to insertion in the direction of arrow F. This "stubbing" of the "non-cocked" connector 110 assures that proper mating forces are established such that the interposer-style contacts in the mating face 124 achieve proper mating with the contact pads 112 of the motherboard 102. With reference now to FIGS. 9-14, a connector coupling structure and the workings thereof will be described in greater detail. The anchor members 14 that extend from the mating face 12 of the motherboard 2 are mechanically retained therein by conventional means such as soldering or press-fit interference. The anchors 14 include a bulbous head portions 31 generally spherical in shape that extend beyond a pin body 34. With reference now to the connector 10, the connector coupler 30 is disposed within a cavity 36 of the housing block 22 and includes a coupling member 38 operatively connected to the housing block 22 by a resilient member 40 which, in this example, is a simple coil spring. The coupler 38 includes a forward section 42 having a receptacle region 44 configured to generally correspond to the head 31 of the anchor 14. The forward portion 42 is divided into multiple resilient fingers 46 that are deflectable to enable the head 32 to enter the receptacle 44. Opposite the forward portion 42 is a rearward section 48 having multiple resilient arms 48. The resilient arms 48 enable the coupler 38 to be pressed into the cavity 36 and then retained beneath a shoulder 52. The cavity 36 further includes a front portion 54 wherein the forward portion 42 of the coupler 38 is received. The coupler 38 is slidable within the cavity 36 between a position (as shown in FIG. 9) where the coil spring 40 is fully compressed and a relaxed position where the rear portions 40 abut the shoulder 52 (FIGS. 11 and 14). With further reference to FIG. 9, the electrical connectors 10 are shown with the terminal block 23 biased forward along the dove-tail 32 and the coupler members 38 biased forward within the cavity 36 so that the forward end 42 of the coupler 30 is extending from a stepped face 56 of the housing block 22. In this position, the resilient fingers 46 of the front end 42 of the coupling member 38 are free from the forward portion 54 of the cavity 36 and may deflect outward so that the head 31 may enter the receptacle 44. Once the head 31 is in the receptacle 44, the spring force of the coil spring 40 may be released and the arms 46 may return into the cavity 36 with the head 31 retained therein, as best shown in FIG. 11. Various mechanical structures may be used to effect the release, such as a release button coupled thereto or a ball-point pen push release. With reference now to FIG. 10, as may be observed, the daughterboard 4 and the associated connectors 10 have been initially fixed to the motherboard 2. In the case the heads 31 of the anchors 14 are engaged within the receptacle portion 44 of the couplers 38. Due to the force exerted by the coil springs 40, the coupling members 38 are gradually being drawn back as the daughterboard 4 moves forward towards the motherboard 2. Provided the components are properly configured and dimensioned, the front face 24 of the terminal block 23 abuts the mating face 12 of the motherboard 2 upon release of the latch mechanism 45,46. This may be best seen in FIG. 11. The terminal block 23 and housing block 22 having coupler members 30 therein are also resiliently coupled. With reference now to FIG. 11, the connector 10 on the daughterboard 4 has been brought into a fully mated position with the motherboard 2 such that the front face 24 is against the mating face 12. In this position, the head 32 of the anchor 14 is within the receptacle 44 and the fingers 46 of the front end 42 are fully retracted within the forward portion 54 of the cavity 36, thereby the fingers 46 are prevented from expanding by the close fit within the forward portion 54. The cooperation of the forward portion 54 and fingers 46 assure that the connector coupler 30 remains engaged with the anchor 14. Also, the force which the connector face 24 abuts the mating face 12 of the motherboard 2 is directly related to the spring members 40 and where used, the resilient member 44 as shown in FIGS. 2-8. As may be further imagined, it is easy to see that the spring members 40 may be used to draw the two components 2,4 together without the need to exert an insertion force against the motherboard 2 as the daughter card 4 is being mated therewith. With reference now to FIGS. 12 and 13, removal of the daughter card 4 from the motherboard 2 will be described. By exerting a force on the daughtercard 4 in the direction arrow F' of FIG. 6, the force exerted by the springs 40 is overcome. In doing so, the outer housing 22 of the connectors 10 will be pulled away from the motherboard 2 and the couplers 38 will remain affixed to the anchors 14 until the forward end 42, and in particular the resilient fingers 46, pass the face 56 so that they are free of the forward portion 54 of the cavity 36. At this point the couplers 38 are retained in the cavity 36 in the cocked position of FIG. 9. Further exertion of the force will result in the resilient fingers 46 opening about the head 31 of the anchor 14 and releasing therefrom. As shown in FIG. 13, the coupler 38 will then be pulled back by spring member 40 and the daughtercard 4 will be free from the motherboard 2. With reference to FIG. 14, unless the couplers 38 are in the cocked position of FIG. 9, it will not be possible to engage the anchors 14. This provides a similar "stubbing" to that described above. Initially, a special tool could be brought against the coupler members 38 to bias them forward into the position shown in FIG. 9. The couplers 138 would then be locked in this position. While the afore going has been described generally with respect to a board-to-board interconnection 1, it should be apparent that the general principles of the anchor 14 and the coupling mechanism to isolate forces could be transferred to other connector applications. In addition, while particular contact structure has not been described in detail it should be apparent that numerous designs would be acceptable, including the afore mentioned "interposer" style interconnection where a spring member contact is biased against a contact pad without mechanically embracing the pad. Advantageously, for high performance, each signal contact is surrounded by a ground contact. Furthermore, while the jumpers 20 have been shown entering from the rear of the terminal block 23 above, it may also be possible to utilize side entry.

An electrical connector for interconnecting a first circuit board to a second circuit board that has a connector housing attachable to the first board, including a base plate in the vicinity of the first board with a plurality of openings for providing access to contact members on the first board; a floating terminal block cooperating with a plurality of individually resilient contacts that rely on normal forces to establish an electrical, flexible conductors extending between the base plate and the electrical contacts to establish an electrical connection between the first board and the second board; a biasing member positioned relative to the housing and the terminal block so that the terminal block, and the plurality of individually resilient contact elements are biased away from the housing, the biasing member exerting a spring force on the terminal block such that a mating force is established between the contacts and the second circuit board is established; and, a coupler for maintaining the relative positions connector to the mating circuit board.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims priority to Chinese Patent Application No. 201610352232.2, filed on May 25, 2016, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD [0002] The present application relates to the technical field of lithium-ion batteries and, specifically, relates to an electrolyte and a lithium-ion battery containing the electrolyte. BACKGROUND [0003] In recent years, with the development of intelligent electronic products, there is an increasingly higher demand on battery life of the lithium-ion battery. In order to increase the energy density of the lithium-ion battery, an effective manner is to develop high-voltage lithium-ion batteries. [0004] At present, the lithium-ion battery with a working voltage is ≧4.4V has become a research hotspot for various R&D institutions and companies. However, when at high voltage, the positive electrode material will has improved oxidation activity and reduced stability, resulting in that the electrochemical oxidizing reaction of the non-aqueous electrolyte will readily occur on the surface of the positive electrode, and thus the electrolyte will decompose and generate gas. At the same time, reduction reaction will occur to the transition metal elements in the positive electrode material, such as nickel, cobalt, manganese and so on, and thus such transition metal elements will precipitate out, which will cause further deterioration of electrochemical performance of the lithium-ion battery. A primary solution at present is to add into the electrolyte a film forming additive which can form a film at the positive electrode, which, however, will increase interface impedance, and thus reduce transport and diffusion kinetic performance of lithium ions in the battery and therefore cause deterioration of rate and cycle performance of the battery. Chainlike carbonate dimers, chainlike carboxylate dimers, chainlike sulfonate dimers or phosphate esters can improve high-temperature storage performance, initial charge/discharge performance, safety and cycle performance, etc., however, it is difficult for these materials to wet the electrode plate and separator as a result of too large viscosities thereof, which therefore, especially under high compact density, causes disadvantageous effects to the cycle performance, rate performance and low-temperature performance of the cell. [0005] With respect to the defects of the prior art, the present application is proposed. SUMMARY [0006] A primary invention object of the present application is to provide an electrolyte. [0007] A secondary invention object of the present application is to provide a lithium-ion cell containing the electrolyte. [0008] In order to accomplish the objects of the present application, the adopted technical solutions include: [0009] The present application relates to an electrolyte, including a lithium salt, an organic solvent and additives, characterized in that, the additives comprise additive A and additive B, wherein the additive A is selected from a group consisting of carbonate dimers, carboxylate dimers, sultone dimers and combinations thereof, and the additive B is selected from a group consisting of fluoroethers and combinations thereof; [0010] the additive A preferably includes a carbonate dimer and/or a carboxylate dimer and a sultone dimer. [0011] Preferably, a structural formula of the carbonate dimer is shown as Formula I: [0000] [0000] in Formula I, R 11 and R 13 are respectively selected from a group consisting of substituted or unsubstituted C 1˜12 alkyls, substituted or unsubstituted C 2˜12 alkenyls, substituted or unsubstituted C 2˜12 alkynyls, substituted or unsubstituted C 6˜26 aryls and substituted or unsubstituted C 5˜22 heteroaryls, wherein each substituting group is selected from a group consisting of halogens, C 6˜26 aryls and C 3˜8 cyclic alkyls; [0012] R 12 is selected from a group consisting of substituted or unsubstituted C 1˜12 alkylenes, substituted or unsubstituted C 6˜26 arylenes and radical groups composed of at least one ether bond and at least one substituted or unsubstituted C 1˜12 alkylene, wherein each substituting group is selected from a group consisting of halogens. [0013] Preferably, a structural formula of the carboxylate dimer is shown as Formula II: [0000] [0000] in Formula II, R 21 and R 23 are respectively selected from a group consisting of substituted or unsubstituted C 1˜12 alkyls, substituted or unsubstituted C 2˜12 alkenyls, substituted or unsubstituted C 2˜12 alkynyls, substituted or unsubstituted C 6˜26 aryls and substituted or unsubstituted C 5˜22 heteroaryls, wherein each substituting group is selected from a group consisting of halogens, C 6˜26 aryls and C 3˜8 cyclic alkyls; [0014] R 22 is selected from a group consisting of substituted or unsubstituted C 1˜12 alkylenes, substituted or unsubstituted C 6˜26 arylenes and radical groups composed of at least one ether bond and at least one substituted or unsubstituted C 1˜12 alkylene, wherein each substituting group is selected from a group consisting of halogens. [0015] Preferably, a structural formula of the sultone dimer is shown as Formula III: [0000] [0000] in Formula III, R 31 and R 33 are respectively selected from a group consisting of substituted or unsubstituted C 1˜12 alkyls, substituted or unsubstituted C 2˜12 alkenyls, substituted or unsubstituted C 2˜12 alkynyls, substituted or unsubstituted C 6˜26 aryls and substituted or unsubstituted C 5˜22 heteroaryls, wherein each substituting group is selected from a group consisting of halogens, C 6˜26 aryls and C 3˜8 cyclic alkyls; [0016] R 32 is selected from a group consisting of substituted or unsubstituted C 1˜12 alkylenes, substituted or unsubstituted C 6˜26 arylenes and radical groups composed of at least one ether bond and at least one substituted or unsubstituted C 1˜12 alkylene, wherein each substituting group is selected from a group consisting of halogens. [0017] Preferably, a structural formula of the fluoroether compound is shown as Formula IV: [0000] R 41 —O—R 42   (IV) [0000] in Formula IV, R 41 and R 42 are respectively selected from a group consisting of C 1˜20 alkyls and C 1˜20 fluoroalkyls; at least one of R 41 and R 42 is a C 1˜20 fluoroalkyl; and the fluoroalkyl is an alkyl of which all or partial hydrogen atoms are substituted by a fluorine; [0018] R 41 and R 42 are preferably selected from a group consisting of C 1˜9 alkyls and C 1˜9 fluoroalkyls, respectively. [0019] Preferably, the fluoroether compound is selected from a group consisting of CF 3 OCH 3 , CF 3 OC 2 H 6 , F(CF 2 ) 2 OCH 3 , F(CF 2 ) 2 OC 2 H 5 , F(CF 2 ) 3 OCH 3 , F(CF 2 ) 3 OC 2 H 5 , F(CF 2 ) 4 OCH 3 , F(CF 2 ) 4 OC 2 H 5 , F(CF 2 ) 5 OCH 3 , F(CF 2 ) 5 OC 2 H 5 , F(CF 2 ) 8 OCH 3 , F(CF 2 ) 8 OC 2 H 5 , F(CF 2 ) 9 OCH 3 , CF 3 CH 2 OCH 3 , CF 3 CH 2 OCHF 2 , CF 3 CF 2 CH 2 OCH 3 , CF 3 CF 2 CH 2 OCHF 2 , CF 3 CF 2 CH 2 O(CF 2 ) 2 H, CF 3 CF 2 CH 2 O(CF 2 ) 2 F, HCF 2 CH 2 OCH 3 , H(CF 2 ) 2 OCH 2 CH 3 , H(CF 2 ) 2 OCH 2 CF 3 , H(CF 2 ) 2 CH 2 OCHF 2 , H(CF 2 ) 2 CH 2 O(CF 2 ) 2 H, H(CF 2 ) 2 CH 2 O(CF 2 ) 3 H, H(CF 2 ) 3 CH 2 O(CF 2 ) 2 H, (CF 3 ) 2 CHOCH 3 , (CF 3 ) 2 CHCF 2 OCH 3 , CF 3 CHFCF 2 OCH 3 , CF 3 CHFCF 2 OCH 2 CH 3 , CF 3 CHFCF 2 CH 2 OCHF 2 and combinations thereof. [0020] Preferably, a total content of the additive A and the additive B is 0.001%˜30% by weight of the electrolyte. [0021] Preferably, the additives further include additive C selected from a group consisting of nitrile compounds, cyclic ester compounds containing a sulfur-oxygen double bond, cyclic carbonate compounds, compounds containing a carbon-nitrogen double bond and combinations thereof; [0022] the nitrile compound is selected from a group consisting of alkanes containing 1˜5 nitrile groupings, olefins containing 1˜5 nitrile groupings and combinations thereof; [0023] the cyclic ether compound containing a sulfur-oxygen double bond is selected from a group consisting of cyclic sulfates, cyclic sulfites, sultones and combinations thereof; [0024] the compound containing a carbon-nitrogen double bond is selected from a group consisting of compounds containing [0000] [0000] and —N═C═N— and combinations thereof. [0025] Preferably, the nitrile compound is selected from a group consisting of C 2˜12 alkanes containing 1˜4 nitrile groupings, C 2˜12 olefins containing 1˜4 nitrile groupings and combinations thereof; [0026] the cyclic ether compound containing a sulfur-oxygen double bond is selected from a group consisting of compounds shown as Formula V1, compounds shown as Formula V2, compounds shown as Formula V3 and combinations thereof; the cyclic carbonate compound is selected from compounds shown as Formula V4 and combinations thereof; [0000] [0027] R 51 , R 52 , R 53 and R 54 are respectively selected from a group consisting of substituted or unsubstituted C 1˜4 alkylenes and substituted or unsubstituted C 2˜4 alkenylenes, wherein each substituting group is selected from a group consisting of halogens and C 2˜4 alkenyls. [0028] Preferably, the additive C is selected from a group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, butenenitrile, 2-methyl-3-butenenitrile, malononitrile, succinonitrile, glutaronitrile, hexanedinitrile, fumarodinitrile, 1,2-ethylene sulfate, 1,3-propylene sulfate, 1,3-propylene sulfite, 1,3-propane sultone, 1,4-butane sultone, prop-1-ene-1,3-sultone, vinylene carbonate, fluoroethylene carbonate, fluorovinylene carbonate, 1,2-difluorovinylene carbonate, vinyl ethylene carbonate, dicyclohexylcarbodiimide and combinations thereof; [0029] a content of the additive C is preferably 0.01%˜10% by weight of the electrolyte. [0030] The present application further relates to a lithium-ion battery including a positive electrode plate containing a positive electrode active material, a negative electrode plate containing a negative electrode active material, a separator for lithium battery and the electrolyte according to the present application. [0031] The technical solutions of the present application can have at least the following beneficial effects: [0032] In the present application, the fluoroethers contained in the electrolyte firstly play a role of surfactants which prompt the wetting of the ester dimers on the electrode plate and separator, so as to compensate for the insufficient wetting ability of the ester dimers as a result of large viscosities thereof. Strong hydrogen bonding interaction readily occurs between a plurality of O═X (X is carbon or sulfur) radical groups of the ester dimers and the fluoroether, which helps the fluoroether form a stable and compact protection film. Due to strong electron pulling effect of the fluorine atom of the fluoroether, the ester dimer will also readily form a film on the negative electrode surface. As a function of the hydrogen bonding interaction between the O═X radical groups in the ester dimer and the fluoroether, the protection film is stable at high temperature or high voltage and will not decompose during cycling. The lithium battery of the present application can realize the object of high voltage, of which the highest normal working voltage can be improved to 4.4˜5.0V, and the lithium battery has good cycle performance, higher capacity retention rate at charge/discharge and improved service life. [0033] The present application is further explained in connection with the following embodiments. It is appreciated that these embodiments are merely used to illustrate the present application but not to limit the scope of the present application. DESCRIPTION OF EMBODIMENTS [0034] The present application proposes an electrolyte, including a lithium salt, an organic solvent and additives, characterized in that, the additives include additive A and additive B, wherein the additive A is selected from a group consisting of carbonate dimers, carboxylate dimers, sultone dimers and combinations thereof, and the additive B is selected from a group consisting of fluoroethers and combinations thereof. [0035] As an improvement to the electrolyte of the present application, the additive A includes a carbonate dimer and/or a carboxylate dimer and a sultone dimer. [0036] As an improvement to the electrolyte of the present application, a structure of the carbonate dimer is shown as Formula I: [0000] [0000] in Formula I, R 11 and R 13 are respectively selected from a group consisting of substituted or unsubstituted C 1˜12 alkyls, substituted or unsubstituted C 2˜12 alkenyls, substituted or unsubstituted C 2˜12 alkynyls, substituted or unsubstituted C 6˜26 aryls and substituted or unsubstituted C 5˜22 heteroaryls, wherein each substituting group is selected from a group consisting of halogens, C 6˜26 aryls and C 3˜8 cyclic alkyls, [0037] R 12 is selected from a group consisting of substituted or unsubstituted C 1˜12 alkylenes, substituted or unsubstituted C 6˜26 arylenes and radical groups composed of at least one ether bond and at least one substituted or unsubstituted C 1˜12 alkylene, wherein each substituting group is selected from a group consisting of halogens. [0038] As an improvement to the electrolyte of the present application, R 11 and R 13 are respectively selected from a group consisting of C 1˜6 alkyls; and R 12 is selected from a group consisting of C 1˜6 alkylenes. [0039] As an improvement to the electrolyte of the present application, partial examples of the carbonate dimer are as follows: [0000] [0040] As an improvement to the electrolyte of the present application, a structure of the carboxylate dimer is shown as Formula II: [0000] [0000] in Formula II, R 21 and R 23 are respectively selected from a group consisting of substituted or unsubstituted C 1˜12 alkyls, substituted or unsubstituted C 2˜12 alkenyls, substituted or unsubstituted C 2˜12 alkynyls, substituted or unsubstituted C 6˜26 aryls and substituted or unsubstituted C 5˜22 heteroaryls, wherein each substituting group is selected from a group consisting of halogens, C 6˜26 aryls and C 3˜8 cyclic alkyls; [0041] R 22 is selected from a group consisting of substituted or unsubstituted C 1˜12 alkylenes, substituted or unsubstituted C 6˜26 arylenes and radical groups composed of at least one ether bond and at least one substituted or unsubstituted C 1˜12 alkylene, wherein each substituting group is selected from a group consisting of halogens. [0042] As an improvement to the electrolyte of the present application, R 21 and R 23 are respectively selected from a group consisting of C 1˜6 alkyls; R 22 is selected from a group consisting of C 1˜12 alkylenes and divalent radical groups obtained by connecting a ether bond with two C 1˜6 alkylenes. [0043] As an improvement to the electrolyte of the present application, partial examples of the carboxylate dimer are as follows: [0000] [0044] As an improvement to the electrolyte of the present application, a structure of the sultone dimer is shown as Formula III: [0000] [0000] in Formula III, R 31 and R 33 are respectively selected from a group consisting of substituted or unsubstituted C 1˜12 alkyls, substituted or unsubstituted C 2˜12 alkenyls, substituted or unsubstituted C 2˜12 alkynyls, substituted or unsubstituted C 6˜26 aryls and substituted or unsubstituted C 5˜22 heteroaryls, wherein each substituting group is selected from a group consisting of halogens, C 6˜26 aryls and C 3˜8 cyclic alkyls; [0045] R 32 is selected from a group consisting of substituted or unsubstituted C 1˜12 alkylenes, substituted or unsubstituted C 6˜26 arylenes and radical groups composed of at least one ether bond and at least one substituted or unsubstituted C 1˜12 alkylene, wherein each substituting group is selected from a group consisting of halogens. [0046] As an improvement to the electrolyte of the present application, R 31 and R 33 are respectively selected from a group consisting of C 1˜6 alkyls; and R 32 is selected from a group consisting of C 1˜6 alkylenes. [0047] As an improvement to the electrolyte of the present application, partial examples of the sultone dimer are as follows: [0000] [0048] As an improvement to the electrolyte of the present application, a structure of the fluoroether compound is shown as Formula IV: [0000] R 41 —O—R 42   (IV) [0000] in Formula IV, R 41 and R 42 are respectively selected from a group consisting of C 1˜20 alkyls and C 1˜20 fluoroalkyls; at least one of R 41 and R 42 is a C 1˜20 fluoroalkyl; and the fluoroalkyl is an alkyl of which all or partial hydrogen atoms are substituted by fluorine; [0049] As an improvement to the electrolyte of the present application, R 41 and R 42 are respectively selected from a group consisting of C 1˜9 alkyls and C 1˜9 fluoroalkyls. [0050] As an improvement to the electrolyte of the present application, the fluoroether compound is selected from a group consisting of CF 3 OCH 3 , CF 3 OC 2 H 6 , F(CF 2 ) 2 OCH 3 , F(CF 2 ) 2 OC 2 H 5 , F(CF 2 ) 3 OCH 3 , F(CF 2 ) 3 OC 2 H 5 , F(CF 2 ) 4 OCH 3 , F(CF 2 ) 4 OC 2 H 5 , F(CF 2 ) 5 OCH 3 , F(CF 2 ) 5 OC 2 H 5 , F(CF 2 ) 8 OCH 3 , F(CF 2 ) 8 OC 2 H 5 , F(CF 2 ) 9 OCH 3 , CF 3 CH 2 OCH 3 , CF 3 CH 2 OCHF 2 , CF 3 CF 2 CH 2 OCH 3 , CF 3 CF 2 CH 2 OCHF 2 , CF 3 CF 2 CH 2 O(CF 2 ) 2 H, CF 3 CF 2 CH 2 O(CF 2 ) 2 F, HCF 2 CH 2 OCH 3 , H(CF 2 ) 2 OCH 2 CH 3 , H(CF 2 ) 2 OCH 2 CF 3 , H(CF 2 ) 2 CH 2 OCHF 2 , H(CF 2 ) 2 CH 2 O(CF 2 ) 2 H, H(CF 2 ) 2 CH 2 O(CF 2 ) 3 H, H(CF 2 ) 3 CH 2 O(CF 2 ) 2 H, (CF 3 ) 2 CHOCH 3 , (CF 3 ) 2 CHCF 2 OCH 3 , CF 3 CHFCF 2 OCH 3 , CF 3 CHFCF 2 OCH 2 CH 3 , CF 3 CHFCF 2 CH 2 OCHF 2 and combinations thereof. [0051] As an improvement to the electrolyte of the present application, the fluoroether compound is selected from a group consisting of F(CF 2 ) 3 OCH 3 , H(CF 2 ) 2 CH 2 O(CF 2 ) 2 H and CF 3 CHFCF 2 CH 2 OCHF 2 . [0052] As an improvement to the electrolyte of the present application, a total content of the additive A and the additive B is 0.001%˜30% by weight of the electrolyte. It is found upon researches that, when the content of the composite additives in the electrolyte is less than 0.001%, the electrolyte cannot effectively form a stable passive film, such that the low-temperature performance and rate performance of the lithium-ion battery cannot be basically improved; when the content of the composite additives in the electrolyte is more than 30%, a relatively thick film is formed, which therefore increases the impedance and reduces the cycle performance of the lithium-ion battery. [0053] As an improvement to the electrolyte of the present application, the total content of the additive A and the additive B is 1˜20% by weight of the electrolyte. The content ratio of the ester dimer compound and the fluoroether compound in the composite additives is not limited. [0054] In the present application, the ester dimer can be obtained by a conventional synthetic method, for example the method disclosed in CN200810107928, or commercially purchased; the fluoroether can be commercially available and its original source is not limited. [0055] As an improvement to the electrolyte of the present application, the additives further include additive C selected from a group consisting of nitrile compounds, cyclic ester compounds containing a sulfur-oxygen double bond, cyclic carbonate compounds, compounds containing a carbon-nitrogen double bond and combinations thereof. When the additives include the additive C, the cycle performance of the lithium-ion battery can be further improved, for example, the lithium-ion battery can have relatively high capacity retention rate after a plurality of cycles at a high voltage≧4.45V. Moreover, the rate performance and the discharge performance of the battery at low temperature can also be further improved. [0056] As an improvement to the electrolyte of the present application, a content of the additive C is 0.01%˜10% by weight of the electrolyte. [0057] In the above-mentioned additive C, the number of the nitrile grouping in the nitrile compound may be 1, 2, 3, 4 or 5; and the nitrile compound is an alkane containing 1˜5 nitrile groupings or an olefin containing 1˜5 nitrile groupings, preferably a C 2˜12 alkane containing 1˜4 nitrile groupings or a C 2˜12 olefin containing 1˜4 nitrile groupings. [0058] The nitrile compound is: a mononitrile compound if it contains only one nitrile grouping, a dinitrile compound if it contains two nitrile groupings, a trinitrile compound if it contains three nitrile groupings, or a tetranitrile compound if it contains four nitrile groupings. In addition, the nitrile compound may further contain a carbon-carbon double bond. Preferably, the nitrile compound is selected from a group consisting of mononitrile compounds, dinitrile compounds, trinitrile compounds, tetranitrile compounds and combinations thereof. [0059] Examples of the nitrile compound may include mononitrile compounds such as acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, 2-methyl butanenitrile, trimethylacetonitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, butenenitrile, 2-methyl-3-butenenitrile, 2-methyl-2-butenenitrile, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile, 2-hexenenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropanenitrile, 3-fluoropropanenitrile, 2,2-difluoropropanenitrile, 2,3-difluoropropanenitrile, 3,3-difluoropropanenitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile and pentafluoropropionitrile; dinitrile compounds such as malononitrile, succinonitrile, tetramethyl-succinonitrile, glutaronitrle, 2-methylglutaronitrile, hexanedinitrile, fumarodinitrile and 2-methyleneglutaronitrile; trinitrile compounds such as 1,3,5-pentanetricarbonitrile, 1,2,3-propanetricarbonitrile and 1,3,6-hexanetricarbonitrile; and tetranitrile compounds such as tetracyanoethylene. [0060] Preferably, the nitrile compound is selected from a group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, butenenitrile, 2-methyl-3-butenenitrile, acrylonitrile, succinonitrile, glutaronitrle, hexanedinitrile (abbreviated as ADN), fumarodinitrile and combinations thereof; more preferably, the nitrile compound is selected from a group consisting of acrylonitrile, succinonitrile, glutaronitrle, hexanedinitrile, fumarodinitrile, 1,3,6-hexanetricarbonitrile and combinations thereof. [0061] Preferably, a content of the nitrile compound is 0.01˜5% by weight of the electrolyte, more preferably 0.1˜3%. [0062] In the abovementioned additive C, the cyclic ester compound containing a sulfur-oxygen double bond may be selected from a group consisting of cyclic sulfates, cyclic sulfites, sultones and combinations thereof, wherein the sultones include saturated sultones and sultones containing an unsaturated double bond. [0063] The cyclic sulfate compounds are shown as Formula V1, the cyclic sulfite compounds are shown as V3, and the sultone compounds are shown as V2: [0000] [0064] R 51 , R 52 and R 53 are respectively selected from a group consisting of substituted or unsubstituted C 1˜4 alkylenes and substituted or unsubstituted C 2˜4 alkenylenes, wherein each substituting group is selected from a group consisting of halogens. [0065] Preferably, R 51 and R 53 are respectively selected from a group consisting of substituted or unsubstituted C 1˜4 alkylenes; R 52 is selected from a group consisting of substituted or unsubstituted C 1˜4 alkylenes and substituted or unsubstituted C 2˜4 alkenylenes. [0066] Preferably, the cyclic ester compound containing a sulfur-oxygen double bond is selected from a group consisting of the following compounds and combinations thereof: [0000] [0000] ethylene sulfate; [0000] [0000] 1,3-propylene sulfate; [0000] [0000] 1,3-propylene sulfite; [0000] [0000] 1,3-propanesultone (abbreviated as PS); [0000] [0000] 1,4-butane sultone; [0000] [0000] prop-1-ene-1,3-sultone. [0067] Preferably, a content of the cyclic ester compound containing a sulfur-oxygen double bond is 0.01˜5% by weight of the electrolyte, more preferably 0.1˜3%. [0068] The cyclic ester compound containing a sulfur-oxygen double bond may be otherwise selected from a group consisting of the following compounds: [0000] [0069] The cyclic carbonate compound includes saturated cyclic carbonates and cyclic carbonates containing an unsaturated carbon-carbon bond, of which the structural formula is shown as Formula V4: [0000] [0070] R 54 is selected from a group consisting of substituted or unsubstituted C 1˜4 alkylenes and substituted or unsubstituted C 2˜4 alkenylenes, wherein each substituting group is selected from a group consisting of halogens and C 2˜4 alkenyls. [0071] In the cyclic carbonate compound containing an unsaturated carbon-carbon bond, the unsaturated carbon-carbon bond is preferably a double bond which may be or may not be located on the ring thereof. [0072] In the abovementioned electrolyte, the cyclic carbonate compound is preferably selected from a group consisting of the following compounds and combinations thereof: [0000] [0000] vinylene carbonate (abbreviated as VC), [0000] [0000] fluoroethylene carbonate; [0000] [0000] fluorovinylene carbonate; [0000] [0000] 1,2-difluorovinylene carbonate; [0000] [0000] vinyl ethylene carbonate. [0073] Preferably, a content of the cyclic carbonate compound is 0.01˜5% by weight of the electrolyte, more preferably 0.1˜3%. [0074] The cyclic carbonate compound may be otherwise selected from a group consisting of the following compounds and combinations thereof: [0000] [0075] In the abovementioned additive C, the compound containing a carbon-carbon double bond is selected from a group consisting of compounds containing an imido-group, compounds containing a carbodiimide group and combinations thereof, wherein the imido-group is shown as [0000] [0000] and the carbodiimide group is shown as —N═C═N—; [0076] the compound containing a carbon-nitrogen double bond is shown as Formula VIa; and the compound containing a carbodiimide group is shown as Formula VIb; [0000] [0077] R 61 , R 62 , R 63 , R 64 and R 65 are respectively selected from a group consisting of substituted or unsubstituted C 1˜12 alkyls and substituted or unsubstituted C 2˜12 alkenyls, wherein each substituting group is selected from a group consisting of halogens. [0078] Examples of the compound containing a carbon-nitrogen double bond can include: [0000] [0079] N-pentyl-isopropyl-imide (abbreviated as NPPI), [0000] [0080] dicyclohexylcarbodiimide (abbreviated as DCC). [0081] Preferably, a content of the compound containing a carbon-nitrogen double bond is 0.01˜5% by weight of the electrolyte, more preferably 0.1˜3%. [0082] In the above-mentioned structural formulas of the present application: [0083] The C 1˜12 alkyl may be a chainlike alkyl or a cyclic alkyl, and a hydrogen on the ring of the cyclic alkyl can be substituted by an alkyl. A straight or branched alkyl is preferred. The lower limit value of the number of carbon atoms in the C 1˜12 alkyl is preferably 2, 3, 4 or 5, and the upper limit value of the number of carbon atoms in the C 1˜12 alkyl is preferably 3, 4, 5, 6, 8, 9, 10 or 11. It is preferred to select a C 1˜10 alkyl, more preferably a C 1˜6 chainlike alkyl or a C 3˜8 cyclic alkyl, further more preferably a C 1˜4 chainlike alkyl or a C 5˜7 cyclic alkyl. Examples of the alkyl may include: methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, neopentyl, hexyl, 2-methylpentyl, 3-methylpentyl, 1,1,2-trimethylpropyl, 3,3-dimethylbutyl, heptyl, 2-heptyl, 3-heptyl, 2-methylhexyl, 3-methylhexyl, iso-heptyl, octyl, nonyl and decyl. [0084] The C 2˜12 alkenyl may be a cyclic alkenyl or a chainlike alkenyl, preferably a straight or branched alkenyl. Further, the alkenyl preferably has only one double bond. A lower limit value of the number of carbon atoms in the alkenyl is preferably 3, 4 or 5, and an upper limit value of the number of carbon atoms in the alkenyl is preferably 6, 8, 10 or 11. It is preferred to select a C 2˜10 alkenyl, more preferably a C 2˜6 alkenyl, further more preferably a C 2˜5 alkenyl. Examples of the alkenyl may include: vinyl, propenyl, isopropenyl, pentenyl, cyclohexenyl, cycloheptenyl and cyclo-octenyl. As for the alkynyle, it can be selected by referring to the selections of the alkenyl. [0085] The C 1˜12 alkylene is a straight or branched alkylene, of which a lower limit value of the number of carbon atoms is preferably 1, 2, 3 or 4, and an upper limit value of the number of carbon atoms is preferably 6, 7, 8, 9, 10 or 11. Examples of the alkylene may include: methylene, 1,2-ethylidene, 1,3-propylidene, 2-methyl-1,3-propylidene, 1,3-dimethyl-propylidene, 1-methyl-1,2-ethylidene, 1,1-dimethylethylidene, 1,2-dimethylethylidene, 1,4-butylidene, 1,5-pentylidene, 1,6-hexylidene, 1,1,4,4-tetramethylbutylidene, cyclopropylidene, 1,2-cyclopropylidene, 1,3-cyclobutylidene, cyclobutylidene, cyclohexylidene, 1,4-cyclohexylidene, 1,4-cycloheptylidene, cycloheptylidene, 1,5-cyclo-octamethylene and cyclo-octamethylene. [0086] The C 2˜12 alkenylene is a straight or branched alkenylene, of which the number and position of the double bond are not limited, which can be selected according to actual demands. In particular, the number of the double bond may be 1, 2, 3 or 4. In the alkenylene, a lower limit value of the number of carbon atoms is preferably 2, 3, 4 or 5, and an upper limit value of the number of carbon atoms is preferably 6, 8, 10 or 11. Examples of the alkenylene may include: 1,2-vinylene, vinylidene, 1,3-propenylene, 2-propenylene, methyl-1,2-vinylene, ethyl-1,2-vinylene, 1,4-tetramethylene-2-alkenyl, 1,5-pentamethylene-2-alkenyl, 1,6-hexamethylene-3-alkenyl, 1,7-heptamethylene-3-alkenyl and 1,8-octamethylene-2-alkenyl. [0087] The C 6˜26 aryl could be, for example a phenyl, a phenylalkyl, a aryl containing at least one phenyl such as biphenyl and polycyclic aromatic group such as naphthyl, anthryl and phenanthryl, and a hydrogen of the biphenyl and the polycyclic aromatic group can be substituted by an alkyl or an alkenyl. It is preferred to select a C 6˜16 aryl, more preferably a C 6˜14 aryl, and further more preferably a C 6˜9 aryl. Examples of the aryl may include: phenyl, benzyl, biphenyl, p-tolyl, o-tolyl and m-tolyl. [0088] The C 5˜22 heteroaryl may include: furyl, thienyl, pyrryl, thiazolyl, imidazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolyl and quinolyl. [0089] The halogen is selected from a group consisting of fluorine, chlorine and bromine, and is preferably selected from a group consisting of fluorine and chlorine. [0090] As an improvement of the electrolyte of the present application, the organic solvent is particularly a non-aqueous organic solvent, preferably selected from a group consisting of compounds having 1˜8 carbon atoms and at least one ester group. [0091] Preferably, the organic solvent is selected from a group consisting of ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, 1,4-butyrolactone, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, ethyl butyrate and combinations thereof. However, the solvent is not limited to the above-mentioned specific compounds, and the solvent may be otherwise selected from fluoro-compounds of the above-mentioned compounds. [0092] In the abovementioned electrolyte, the lithium salt is elected from a group consisting of organic lithium salts, inorganic lithium salts and combinations thereof. Particularly, the lithium salt contains at least one element of fluorine, boron and phosphorus. [0093] Examples of the lithium salt may include: lithium hexafluorophosphate LiPF 6 , lithium difluorophosphate LiPO 2 F 2 , lithium tetrafluoroborate LiBF 4 , lithium bis(trifluoromethanesulphonyl)imide LiN(CF 3 SO 2 ) 2 (abbreviated as LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 ) (abbreviated as LiFSI), lithium bis(oxalate)borate LiB(C 2 O 4 ) 2 (abbreviated as LiBOB), lithium oxalyldifluoroborate LiBF 2 (C 2 O 4 ) (abbreviated as LiDFOB). [0094] In the abovementioned electrolyte, the lithium salt is preferably selected from a group consisting of lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium trifluorosulfonate, lithium bis(trifluoromethylsulfonyl) imide, lithium bis(fluorosulfonyl) imide, lithium tris(trifluoromethylsulfonyl) methide and combinations thereof. [0095] Particularly, the concentration of the lithium salt can be 0.5mol/L˜3 mol/L. [0096] In the present application, the electrolyte can be prepared by a conventional manner, for example, to evenly mix all the materials in the electrolyte. [0097] Another object of the present application is to provide a lithium-ion battery, including a positive electrode plate, a negative electrode plate, a separator for lithium battery and the electrolyte of the present application. [0098] In the abovementioned lithium-ion battery, the positive electrode plate includes a positive electrode active material; the negative electrode plate includes a negative electrode active material; and the specific types of the positive electrode active material and the negative electrode active material are not limited, which can be selected according to actual demands. [0099] Preferably, the positive electrode active material is selected from a group consisting of lithium cobaltate (LiCoO 2 ), lithium nickel-manganese-cobalt oxide, lithium ferrous phosphate (LiFePO 4 ), lithium manganate (LiMn 2 O 4 ) and combinations thereof. [0100] Preferably, the negative electrode active material is carbon and/or silicon, for example, natural graphite, artificial graphite, mesocarbon microbeads (abbreviated as MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li—Sn alloy, Li—Sn—O alloy, Sn, SnO, SnO 2 , lithiated TiO 2 —Li 4 Ti 5 O 12 with a spinel structure and Li—Al alloy are all suitable as the negative electrode active material. [0101] The present application is further described in connection with the following embodiments. It should be noted that, these embodiments are merely exemplary, which do not constitute any limit to the protection scope of the present application. [0102] In the following embodiments, comparative examples and test examples, all used reagents, materials and instruments could be commercially available unless otherwise noted, and the used reagents can also be obtained by conventional manners. Embodiments 1˜15 [0103] In the following embodiments, comparative examples and test examples, the used materials are listed as follows [0104] Organic solvent: ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC); Lithium salt: LiPF 6 ; [0105] Additive A: Ester Dimers; [0106] Carbonate dimer: 2-ethoxycarbonyloxyethyl ethyl carbonate (AN1); [0000] [0107] Carboxylate dimer: diethylene glycol diacetate (AN2); [0000] [0108] Sultone dimer: 4-methansulfonyloxy-butyl methanesulfonate (AN3) [0000] [0109] Additive B: Fluoroether: [0000] F(CF 2 ) 3 OCH 3   (AM1); [0000] CF 3 CHFCF 2 CH 2 OCHF 2   (AM2); [0000] H(CF 2 ) 2 CH 2 O(CF 2 ) 2 H   (AM3); [0110] Additive C: [0111] fluoroethylene carbonate (FEC); [0112] vinylene carbonate (VC); [0113] 1,3-propanesultone (PS); [0114] hexanedinitrile (ADN); [0115] Separator for lithium battery: polypropylene separator membrane with a thickness of 16 μm (Model: A273, provided by Celgard Corporation). [0116] Lithium batteries (hereinafter referred to as batteries) 1˜15 are all prepared according to the following manner: [0117] (1) Preparation of Positive Electrode Plate [0118] Lithium cobaltate (LiCoO 2 ), a binder (polyvinylidene fluoride) and a conductive agent (acetylene black) are mixed in a weight ratio of LiCoO 2 : polyvinylidene fluoride: acetylene black=96:2:2, then added with N-methylpyrrolidone (NMP) and stirred by a vacuum mixer to form a uniform and transparent state, so as to obtain a positive electrode slurry; the positive electrode slurry is then evenly coated onto an alumunium foil with a thickness of 12 μm, dried at room temperature and then dried in an oven at 120° C. for 1 hour, then cold-pressed and slit, so as to obtain a positive electrode plate. [0119] (2) Preparation of Negative Electrode Plate [0120] Graphite, acetylene black, sodium carboxymethylcellulose (CMC) thickener and styrene-butadiene rubber binder are mixed in a weight ratio of graphite: acetylene black: styrene-butadiene rubber binder: sodium carboxymethylcellulose thickener=95:2:2:1, then added with deionized water and stirred by a vacuum mixer, so as to form a negative electrode slurry; the negative electrode slurry is then evenly coated onto a copper foil, dried at room temperature and then dried in an oven at 120° C. for 1 hour, then cold-pressed and slit, so as to obtain a negative electrode plate. [0121] (3) Preparation of Electrolyte [0122] Electrolytes 1˜15 are prepared according to the following manner: [0123] In a glove box filled with argon atmosphere with a moisture content<10 ppm, EC, PC and DEC are evenly mixed in a weight ratio of 1:1:1 so as to form an organic solvent; the lithium salt which has been fully dried is then dissolved into the abovementioned organic solvent; the additive A (AN1, AN2, AN3, AM1, AM2, AM3) and additive B (FEC, VC, PS, ADN, EDN) are then added into the organic solvent according to the content shown in Table 1 and evenly mixed, so as to obtain an electrolyte, of which the concentration of the lithium salt is 1 mol/L, and the weight ratio of EC, PC and DEC is EC: PC: DEC=1:1:2. [0124] (4) Preparation of Lithium-Ion Battery [0125] The positive electrode plate, separator for lithium battery and negative electrode plate are stacked in sequence and then winded to form a bare cell, such that the separator can insulate the positive electrode plate from the negative electrode plate; the bare cell is then packaged into an external packaging foil, then injected with the prepared electrolyte, vacuum sealed, let standby, formed and shaped, so as to obtain a battery. [0126] During the preparation of the abovementioned batteries, the selected electrolyte in each battery and the specific type and contents of the used additive A and additive B in each electrolyte are shown in Table 2. [0127] In Table 1, the content of the additive is a weight percentage counted based on the total weight of the electrolyte. [0000] TABLE 1 Relevant parameters of additives of electrolytes in Comparative examples 1~8 and Embodiments 1~15 Content (%) of additive in electrolyte Additive A Additive B Additive C AN1 AN2 AN3 AM1 AM2 AM3 PS VC ADN FEC Embodiment 0.01 — — — 0.1 — — — — — 1 Embodiment 1 — — 2 — — — — — — 2 Embodiment 1 — — — 2 — 2 1 — — 3 Embodiment 1 — — — — 2 2 1 — — 4 Embodiment 5 — — — 10 — 2 1 — — 5 Embodiment 8 — — — — 2 2 1 — — 6 Embodiment — 5 — — — 10 2 1 — — 7 Embodiment — 5 — — — 10 2 1 1 1 8 Embodiment 10 — — — — 10 2 1 1 1 9 Embodiment — — 15 — — 15 3 1 1 1 10 Embodiment — — 20 — — 15 3 2 2 1 11 Embodiment 5 — 5 — — 2 — — — — 12 Embodiment 5 — 5 — — 2 2 1 — — 13 Embodiment — 5 5 — — 2 — — — — 14 Embodiment — 5 5 — — 2 2 1 — — 15 Comparative — — — — — — — — — — example 1 Comparative — — — — — — 2 1 — — example 2 Comparative — — — — — 2 2 1 — — example 3 Comparative — — 2 — — — 2 1 — — example 4 Comparative 2 — — — — — — — — — example 5 Comparative — — — — — 2 — — — — example 6 Comparative 0.01 — — — — — — — — — example 7 Comparative 20 — — 20 — — — — — — example 8 [0128] Performance Test Manners: [0129] (1) Test for Cycle Performance of Battery [0130] At 45° C., the lithium-ion batteries of Embodiments 1-15 and Comparative examples 1-8 are charged with a constant current at a rate of 0.5 C to 4.45V, then charged with a constant voltage to a current of 0.05 C, then discharged with a constant current of 0.5 C to 3.0V, then repeat the charge and discharge as above and respectively calculate the capacity retention rates after 50 cycles, 100 cycles and 300 cycles. [0131] Capacity retention rate after n cycles=(discharge capacity after the n th cycle/discharge capacity after the first cycle)×100%. Relevant data is shown in Table 2. [0132] (2) Test for high-temperature storage performance of battery [0133] The following test is conducted to each of the batteries obtained in Embodiments 1˜15 and Comparative examples 1˜8: [0134] At 25° C., a battery is charged with a constant current of 0.5 C to 4.45V, charged with a constant voltage of 4.45V to a current of 0.025 C and let to be in a fully charged state when the measured thickness is the thickness before storage; then, the battery is respectively stored at 85° C. for 4 hours and 60° C. for 30 days, the thicknesses of the battery after storage are respectively measured, and the thickness expansion rate of the battery after storage at different conditions are calculated in the following formula. The thicknesses of the batteries after storage at different conditions are shown in Table 2. [0000] Thickness expansion rate of battery=[(thickness before storage−thickness after storage)/thickness before storage]×100% [0000] TABLE 2 Testing results of relevant performance of Embodiments 1~15 and Comparative examples 1~8 Thickness expansion rate (%) After After Cycle performance storage at storage at 50 100 300 85° C. for 60° C. for cycles cycles cycles 4 hours 30 days Embodiment 80.9 75.6 71.8 9.3 6.4 1 Embodiment 86.9 83.5 82.5 9.7 12.1 2 Embodiment 94.7 94.2 89.5 8.1 6.7 3 Embodiment 89.7 89.2 84.5 6.7 7.9 4 Embodiment 87.5 82.9 81.2 7.8 9.15 5 Embodiment 93 90.1 85.9 5.6 7.3 6 Embodiment 88.4 87.6 85.2 5.4 6.9 7 Embodiment 96.3 94.9 91.7 4.3 6.2 8 Embodiment 95.1 93.5 91.5 4.5 6.4 9 Embodiment 93.5 91.3 88.8 3.8 6.1 10 Embodiment 93.1 90.3 87.4 4.9 7.5 11 Embodiment 96.7 95.2 93.2 3.2 4.6 12 Embodiment 97.3 96.1 92.9 2.9 4.3 13 Embodiment 97.1 95.9 93.6 2.9 4.7 14 Embodiment 97.8 96.8 94.2 2.2 4.5 15 Comparative 45.1 39.4 35.2 32.8 39.1 example 1 Comparative 57.2 53.5 46.3 27.9 35.3 example 2 Comparative 59.5 54.8 48.7 25.3 31.2 example 3 Comparative 64.2 58.2 50 24.1 30.6 example 4 Comparative 67 59.65 49.4 18.5 26.7 example 5 Comparative 72 66.7 62.55 16.2 21.5 example 6 Comparative 46.1 40.2 36.1 30.3 38.5 example 7 Comparative 54.3 51.2 45.6 28.1 31.2 example 8 [0135] (3) Hot-Box Test [0136] The following test is conducted to each of the batteries obtained in Embodiments 1˜15 and Comparative examples 1˜8: [0137] 1) charging the battery with a constant current of 1.0 C to 4.45V, then charging with a constant voltage until the current reduces to 0.05 C, and then stop charging. [0138] 2) placing the battery in a hot box, increasing the temperature from 25° C. to 150° C. at a heating rate of 5° C./min, maintaining the temperature at 150° C. and begin timing, 1 hour later, observing the state of the battery; the standard for passing the test includes no fuming, no fire and no explosion, and each group has 5 batteries. The result of hot-box test for each battery is shown in Table 4. [0139] The safety performance of the battery is characterized by the above hot-box test. [0000] TABLE 3 Testing results of relevant performance of Embodiments 1~15 and Comparative examples 1~8 Battery No. State after hot-box test Embodiment All 5 batteries pass the test with no fume, 1 no fire and no explosion Embodiment 4 batteries pass the test and the other 2 1 battery is on fire Embodiment All 5 batteries pass the test with no fume, 3 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 4 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 5 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 6 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 7 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 8 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 9 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 10 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 11 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 12 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 13 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 14 no fire and no explosion Embodiment All 5 batteries pass the test with no fume, 15 no fire and no explosion Comparative All 5 batteries are on fire example 1 Comparative All 5 batteries are on fire example 2 Comparative 1 battery passes the test and the other example 3 4 batteries are on fire Comparative 1 battery passes the test and the other example 4 4 batteries are on fire Comparative 2 batteries pass the test and the other example 5 3 batteries are on fire Comparative 2 batteries pass the test and the other example 6 3 batteries are on fire Comparative 2 batteries pass the test and the other example 7 3 batteries are on fire Comparative 2 batteries pass the test and the other example 8 3 batteries are on fire [0140] It can be known from the relevant data in Tables 2˜4 that, in Comparative examples 1˜8, Comparative examples 3˜6 containing only one of carbonate dimer and fluoroether of the additive A have reduced capacity retention rate and reduced rate performance due to relatively high impedance during the formation of the film. However, Embodiments 1˜11 adopt the combination of ester dimer and fluoroether compound, which can reduce the thickness of the SEI film on the positive electrode surface and reduce the impedance, and improve uniformity and stability of the SEI film formed on the positive electrode surface, so as to improve the rate performance and low-temperature discharge performance of the lithium-ion battery. Such effect is particularly significant in Embodiments 12˜14 which adopt a combination of carbonate dimer or carboxylate dimer and sultone dimmer, since the formed complex SEI film has a stable structure and thus has good stability during cycling, and will not readily be decomposed and re-formed repeatedly during cycling. The batteries of Embodiments 1˜15 perform better than the batteries of Comparative examples 1˜8 in capacity retention rate, rate performance, low-temperature discharge performance and safety performance after cycling at 45° C. [0141] The lithium-ion battery will have further improved cycle performance if the additives further include the additive C, for example, the lithium-ion battery has relatively high capacity retention rate after a plurality of cycles at a voltage≧4.45V, and further improved rate performance and low-temperature discharge performance. Embodiments 16˜22 [0142] Electrolytes and lithium-ion batteries are prepared according to the manner of Embodiment 1, except that the components of the additives in the electrolytes are shown in Table 4: [0000] TABLE 4 Electrolyte Type and content (%) of additive No. Additive A Additive B Additive C Electrolyte 16 F(CF 2 ) 2 OC 2 H 5 2% FEC 1% + VC 1% Electrolyte 17 F(CF 2 ) 4 OC 2 H 5 2% FEC 1% + PS 1% Electrolyte 18 F(CF 2 ) 3 OCH 3 2% ADN 1% + PS 1% + VC 1% Electrolyte 19 F(CF 2 ) 9 OCH 3 2% FEC 1% + ADN 1% + PS 1% Electrolyte 20 CF 3 CH 2 OCH 3 2% ADN 1% + PS 1% + VC 1% Electrolyte 21 CF 3 CH 2 OCHF 2 2% FEC 1% + ADN 1% + PS 1% Electrolyte 22 (CF 3 ) 2 CHCF 2 OCH 3 2% FEC 1% + ADN 1% [0143] The lithium-ion batteries are prepared by adopting the electrolytes in Table 4 and the prepared batteries have similar properties with Embodiment 1, which will not be repeated herein. [0144] According to the disclosure above, those skilled in the art can make appropriate variations and modifications to the embodiments above. Thus, the present application is not limited to the embodiments as disclosed and descried above, and the variations and modifications made to the present application shall also fall into the protection scope of the claims of the present application.

The present application relates to the technical field of lithium-ion batteries and, specifically, relates to an electrolyte and a lithium-ion battery containing the electrolyte. The electrolyte of the present application includes a lithium salt, an organic solvent and additives, the additives include a fluorinated ether compound and an ester dimer compound, the ester dimer compound includes carbonate dimers, carboxylate dimers and sultone dimers. The lithium battery adopting the electrolyte of the present application can realize the object of high voltage, of which the highest normal working voltage can be improved to 4.4˜5.0V, and the lithium battery has good cycle performance, such as higher capacity retention rate at charge or discharge and improved service life.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic valve to be provided, for example, in a hydraulic control circuit of an automatic transmission of an automobile, FIG. 8 is an illustration of an automatic transmission of the prior art that may be used with the inventive hydraulic valve. 2. Description of the Related Art Conventionally, an electromagnetic valve has been known in which a spool, which is accommodated in a valve housing so as to be capable of reciprocating, rests at a position where equilibrium is attained between the following forces: the urging force of a coil spring urging the spool toward a linear solenoid, a driving force generated by a current supplied to a coil which causes a plunger to be attracted to an attracting portion to thereby cause a shaft to push the spool, and a force received by the spool from an oil chamber of a feedback chamber (see, for example, JP 2003-139261 A ( FIG. 1 )). However, the housing has an input port formed so as to be perpendicular to the axis of the spool, so that working fluid having passed the input port is guided to the interior of the housing of the electromagnetic valve while perpendicularly colliding with the spool; thus, a lateral force due to the collision dynamic pressure of the working fluid acts on the spool, resulting in an increase in the sliding resistance during the operation of the spool and a sealing defect when shutting off the working fluid. Further, the working fluid is divided, starting from the point at which it collides with the spool, into a plurality of flows along the outer peripheral surface thereof, and these flows join again on the opposite side of the inflow port, thus generating a complicated flow; thus, the working fluid undergoes a marked reduction in velocity and an increase in fluid resistance, resulting in a deterioration in the efficiency with which the working fluid is discharged through a discharge hole; further, foreign matter (contaminant) contained in the working fluid also enters the housing and undergoes a reduction in velocity as the working fluid is decelerated, and is liable to stay around the spool, with the result that foreign matter is caught between the sliding surfaces of the spool and the housing. SUMMARY OF THE INVENTION The present invention has been made with a view toward solving the above problems in the prior art. It is an object of the present invention to provide an electromagnetic valve in which a force due to a fluid from an inflow hole acting in a direction perpendicular to the axis of a first valve is reduced to thereby reduce the sliding resistance of the first valve and in which the fluid flowing in through the inflow hole flows smoothly through an inner flow path, achieving an improvement in terms of the efficiency with which the fluid is discharged through a discharge hole. An electromagnetic valve according to the present invention includes: a housing having an inflow hole through which a fluid flows in, an inner flow path communicating with the inflow hole, and a discharge hole through which the fluid is discharged to an exterior; a valve seat secured in position inside the housing; a first valve adapted to abut one surface of the valve seat to shut off the fluid flowing into the inner flow path through the inflow hole; and a second valve provided coaxially with the first valve and adapted to control, through adjustment of a dimension of a gap between the second valve and the other surface of the valve seat, an amount of fluid flowing to the exterior of the housing through the discharge hole. In the electromagnetic valve, the housing is equipped with a whirling means for causing the fluid having flowed into the inner flow path through the inflow hole to whirl in one direction. In the electromagnetic valve of the present invention, the force due to the fluid from the inflow hole acting in the direction perpendicular to the axis of the first valve is reduced to thereby reduce the sliding resistance of the first valve, and the fluid flowing in through the inflow hole flows smoothly through the inner flow path, thus achieving an improvement in terms of the efficiency with which the fluid is discharged through the discharge hole. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIG. 1 is a front sectional view of a proportional electromagnetic valve for pressure control according to Embodiment 1 of the present invention; FIG. 2 is a sectional view taken in the direction of arrows A of FIG. 1 ; FIG. 3 is a front sectional view of a main portion of a proportional electromagnetic valve for pressure control according to Embodiment 2 of the present invention; FIG. 4 is a sectional view taken in the direction of arrows B of FIG. 3 ; FIG. 5 is a diagram showing the relationship between lead per perimeter and the inner diameter of an inflow hole; FIG. 6 is a front sectional view of a main portion of a proportional electromagnetic valve for pressure control according to Embodiment 3 of the present invention; and FIG. 7 is a sectional view taken in the direction of arrows C of FIG. 6 . FIG. 8 is an illustration of an automatic transmission in an automobile that may be used with the inventive hydraulic valve. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described with reference to the drawings; the members and portions that are the same as or equivalent to each other are indicated by the same symbols. Embodiment 1 FIG. 1 is a front sectional view of a proportional electromagnetic valve for pressure control according to Embodiment 1 of the present invention, and FIG. 2 is a sectional view taken in the direction of arrows A of FIG. 1 . This proportional electromagnetic valve for pressure control (hereinafter simply referred to as the electromagnetic valve) consists of a normally-low type three-way proportional electromagnetic valve for hydraulic control in an automatic transmission. In this electromagnetic valve, a coil 3 is provided inside a yoke 1 and a plate 2 forming a magnetic circuit. A plunger 4 is provided on the inner side of the coil 3 . A rod 5 extends through this plunger 4 . At the ends of the rod 5 , there are provided a first slide bearing 6 and a second slide bearing 7 supporting the rod 5 so as to allow it to move in the axial direction. Fixed to the yoke 1 is a core 8 axially opposed to the plunger 4 and surrounding the rod 5 . Fixed to the lower portion of the core 8 is a housing 10 locked to a flange 22 . Inside the housing 10 , there are formed an inflow hole 11 through which working fluid flows in, an inner flow path 12 communicating with the inflow hole 11 , a discharge hole 13 through which the working fluid is discharged to the exterior, and an output hole 14 . Inside the housing 10 , there is secured in position a valve seat 15 in which a through-hole 25 is formed so as to extend along the center axis. Under the valve seat 15 and inside the housing 10 , there is secured in position a cylindrical sleeve 18 . Provided inside the sleeve 18 is a shut-off valve 16 serving as a first valve which is coaxial with the rod 5 and which can vertical slide relative to the sleeve 18 . The shut-off valve 16 is urged toward the valve seat 15 by the elastic force of a spring 19 . The shut-off valve 16 has a passage 20 extending along the center axis, and, in the upper end portion of the passage 20 , there are formed a pair of holes 24 opposed to the inner wall surface of the valve seat 15 . Under the core 8 , there is provided a guide portion 23 extending toward the shut-off valve 16 . A spherical pressure regulating valve 17 , guided by the guide portion 23 and serving as a second valve, is provided between the rod 5 and the shut-off valve 16 . Provided in the housing 10 is a whirling means for whirling in one direction the working fluid flowing into the inner flow path 12 from the inflow hole 11 . As shown in FIG. 2 , in this embodiment, the whirling means is formed by a circular wall surface 12 a of the inner flow path 12 and the inflow hole 11 which is in a plane perpendicular to the axis of the rod 5 and which extends tangentially with respect to the wall surface 12 a. Next, the operation of the electromagnetic valve constructed as described above will be illustrated. First, at the time of non-energization, that is, when no current is flowing through the coil 3 , the pressure regulating valve 17 is at the maximum lift position, and a shoulder portion 26 of the shut-off valve 16 is caused to abut the lower surface of the valve seat 15 by the elastic force of the spring 19 . Thus, at this time, the working fluid, which enters the housing 10 through the inflow hole 11 , is shut off by the shut-off valve 16 , and the output hole 14 and the discharge hole 13 communicate with each other through the passage 20 and the holes 24 of the shut-off valve 16 , with the pressure on the output hole 14 side being equal to the pressure on the discharge hole 13 side. When an electric current is supplied to the coil 3 through a terminal 21 , a magnetic line of force is generated in the coil 3 , and a magnetic flux flows through the magnetic circuit formed by the plunger 4 , the plate 2 , the yoke 1 , and the core 8 , generating a magnetic attracting force between the plunger 4 and the core 8 . As a result, the plunger 4 is attracted toward the core 8 , and the rod 5 , which is integral with the plunger 4 , moves downwards, and the pressure regulating valve 17 , which is in contact with the rod 5 , also moves downwards against the repulsive force from the shut-off valve 16 . At this time, the magnetic attracting force from the core 8 , the elastic force of the spring 19 , and the fluid force applied through the output hole 14 act on the pressure regulating valve 17 , which moves downwards to a position where these forces are in equilibrium with each other. At the same time, the shut-off valve 16 , which is pressurized by the pressure regulating valve 17 , also moves downwards, and the shoulder portion 26 of the shut-off valve 16 is separated from the lower surface of the valve seat 15 , with the result that the working fluid is guided from the inflow hole 11 to the discharge hole 13 through the inner flow path 12 , and, at the same time, from the inflow hole 11 to the output hole 14 through the inner flow path 12 and the passage 20 . The dimension of the gap between the lower surface of the valve seat 15 and the shoulder portion 26 of the shut-off valve 16 is proportional to the electric current flowing through the coil 3 , and the output pressure applied through the output hole 14 is controlled linearly. Further, when the shut-off valve 16 , which is pressurized by the pressure regulating valve 17 , moves downwards, the pressure regulating valve 17 abuts a shoulder portion 27 of the valve seat 15 , and the working fluid is guided solely to the output hole 14 from the inflow hole 11 through the inner flow path 12 and the passage 20 . In the electromagnetic valve of this embodiment, the inflow hole 11 is provided so as to be in a plane perpendicular to the axis of the rod 5 and as to extend tangentially with respect to the wall surface 12 a of the inner flow path 12 , so that the working fluid flows in a whirl around the center axis of the shut-off valve 16 , and the lateral force applied to the shut-off valve 16 is mitigated. Thus, the sliding resistance of the shut-off valve 16 inside the sleeve 18 is reduced, and it is possible to prevent a sealing defect, a characteristic defect, or adhesion of the working fluid to the inner surface of the sleeve 18 at the time of working fluid shut-off due to defective sliding. Further, the supplied working fluid having passed the inflow hole 11 flows smoothly in the inner flow path 12 along the wall surface 12 a thereof, and a reduction in velocity and pressure loss in the inner flow path 12 are mitigated. Thus, the efficiency with which the working fluid is discharged through the discharge hole 14 is improved, so that any foreign matter, which passes through the inflow hole 11 and enters the housing 10 together with the working fluid, is smoothly discharged through the discharge hole 13 together with the working fluid, and the amount of foreign matter staying in the vicinity of the shut-off valve 16 is reduced. Embodiment 2 FIG. 3 is a front sectional view of a main portion of a proportional electromagnetic valve for pressure control according to Embodiment 2 of the present invention, and FIG. 4 is a sectional view taken in the direction of arrows B of FIG. 3 . This embodiment differs from Embodiment 1 in that the inner flow path 12 has a bottom portion 28 formed in a spiral configuration; otherwise, it is of the same construction as Embodiment 1. In this embodiment, the whirling means is formed by the wall surface 12 a of the inner flow path 12 formed in a circular configuration, the inflow hole 11 in a plane perpendicular to the axis and extending tangentially with respect to the wall surface 12 a , and the spirally formed bottom portion 28 of the inner flow path 12 . In this embodiment, the bottom portion 28 of the inner flow path 12 is spiral, so that the working fluid flowing in through the inflow hole 11 can, upon making a round along the wall surface 12 a , reduce the amount thereof colliding with working fluid newly flowing in through the inflow hole 11 , whereby it is possible to further stabilize the whirl flow of working fluid in the inner flow path 12 . When an inclination angle a of the bottom portion 28 with respect to the plane perpendicular to the axis is a value larger than that obtained from the equation in FIG. 5 , tan α=d/π×D (where d is the inner diameter of the inflow hole, and D is the inner diameter of the inner flow path 12 ), the lead per perimeter of the inner flow path 12 is larger than the inner diameter dimension of the inflow hole 11 , so that it is possible to further stabilize the whirl flow of working fluid in the inner flow path 12 . It is to be noted that, from the viewpoint of workability, it is desirable to adopt a resin material for the housing 10 of Embodiment 2. Embodiment 3 FIG. 6 is a front sectional view of a main portion of a proportional electromagnetic valve for pressure control according to Embodiment 3 of the present invention, and FIG. 7 is a sectional view taken in the direction of arrows C of FIG. 6 . This embodiment differs from Embodiment 1 in that the inflow hole 11 is inclined with respect to the plane perpendicular to the axis; otherwise, it is of the same construction as Embodiment 1. In this embodiment, the whirling means consists of the wall surface 12 a of the inner flow path 12 formed in a circular configuration and the inflow hole 11 inclined with respect to the plane perpendicular to the axis and extending tangentially with respect to the wall surface. In this embodiment, it is possible to obtain the same effect as that of Embodiment 1; further, since the inflow hole 11 is inclined with respect to the plane perpendicular to the axis, the working fluid having flowed in through the inflow hole 11 can, upon making a round along the wall surface 12 a , reduce the amount thereof colliding with working fluid newly flowing in through the inflow hole 11 , making it possible to further stabilize the whirl flow of working fluid in the inner flow path 12 . When an inclination angle β of the inflow hole 11 with respect to the plane perpendicular to the axis is a value larger than the value obtained by the equation: tan β=d/π×D (where d is the inner diameter of the inflow hole, and D is the inner diameter of the inner flow path 12 ), the lead per perimeter of the inner flow path 12 is larger than the inner diameter dimension of the inflow hole 11 , so that it is possible to further stabilize the whirl flow of working fluid in the inner flow path 12 . It is to be noted that, from the viewpoint of workability, it is desirable to adopt a metal material for the housing 10 of Embodiment 3. FIG. 8 is an illustration of an automatic transmission 30 in an automobile 34 that may be used with the inventive hydraulic valve of the above-noted embodiments. While the above-described embodiments are applied to a normally-low type electromagnetic valve, which is a three-way type proportional electromagnetic valve to be used for hydraulic control in an automatic transmission, they are also applicable to a normally-high type electromagnetic valve, in which the operating direction of the plunger upon energization is reversed. Further, the present invention is also applicable to a so-called flow rate switching valve. Further, while in the above-described embodiments the inflow hole 11 extends tangentially with respect to the wall surface 12 a of the inner flow path 12 formed in a circular configuration, this should, of course, not be construed restrictively. For example, by forming the inflow hole in the housing so as to direct it between a radial axis of the shut-off valve and the wall surface of the inner flow path, it is possible to cause the working fluid flowing into the inner flow path through the inflow hole to whirl in one direction.

Disclosed is an electromagnetic valve in which a force due to a working fluid from an inflow hole acting perpendicularly with respect to the axis of a shut-off valve is reduced to thereby reduce the sliding resistance of the shut-off valve. An electromagnetic valve according to the present invention includes: a housing ( 10 ) having an inflow hole ( 11 ), an inner flow path ( 12 ), and a discharge hole ( 13 ); a valve seat ( 15 ) secured in position inside the housing ( 10 ); a shut-off valve ( 16 ) adapted to abut one surface of the valve seat ( 15 ) to shut off the working fluid flowing into the inner flow path ( 12 ) through the inflow hole ( 11 ); and a pressure regulating valve ( 17 ) provided coaxially with the shut-off valve ( 16 ) and adapted to control, through adjustment of the dimensions of a gap between itself and the other surface of the valve seat ( 15 ), the amount of working fluid flowing to the exterior of the housing ( 10 ) through the discharge hole ( 13 ). In the electromagnetic valve, the housing ( 10 ) is equipped with a whirling member for causing the working fluid having flowed into the inner flow path ( 12 ) through the inflow hole ( 11 ) to whirl in one direction.

This application is a US National Stage of International Application No. PCT/CN2014/070729, filed Jan. 16, 2014, designating the United States, and claiming the benefit of Chinese Patent Application No. 201310021861.3, filed with the State Intellectual Property Office of People's Republic of China on Jan. 21, 2013 and entitled “Method and device for scheduling resource in coordinated multi-point transmission”, which is hereby incorporated by reference in its entirety. FIELD The present invention relates to the field of wireless communications and particularly to a method and device for scheduling resources in coordinated multi-point transmission. BACKGROUND Coordinated Multi-Point (CoMP) transmission technology has been applied in a Long Term Evolution-Advance (LTE-A) system, to thereby reduce interference from an adjacent cell for a User Equipment (UE) at the edge of a coverage area of a small cell, so as to improve an experience of the UE at the edge of the cell. Coordinated Multi-Point (CoMP) transmission technology refers to coordination between multiple Transmission Points (TPs) separate in geographical position. Typically multiple transmission points refer to base stations of different cells, or a base station of a cell and multiple Remote Radio Heads (RRHs) controlled by the base station. CoMP transmission technology can be categorized into downlink coordinated transmission and uplink joint reception. Downlink coordinated multi-point transmission is generally further categorized into two transmission schemes of Coordinated Scheduling/Coordinated Beam-forming (CS/CB) and Joint Processing (JP). In the CS/CB scheme, one of multiple transmission points transmits a useful signal to the UE, and interference of the other transmission points to the UE is reduced as much as possible through joint scheduling and beam-forming. The joint processing scheme can be further categorized into Joint Transmission (JT) scheme and Dynamic Point Selection (DPS) scheme. In the JT scheme, multiple transmission points transmit useful signals to the UE concurrently, to thereby enhance the received signal of the UE. In the DPS scheme, the transmission point to the UE is switched dynamically, by selecting the optimum one for the UE among the cooperating transmission points, to transmit a signal to the UE. These schemes of coordinated multi-point transmission may be applied in combination with each other, or may be combined with Dynamic Blanking, to disable some transmission points from transmitting signals over some time-frequency resources. The base stations needs to exchange a large amount of information and data in coordinated multi-point transmission. Information and data are exchanged between the base stations in a Long Term Evolution (LTE) system via an X2 interface. An information transmission rate and a transmission delay via the X2 interface are determined by the characteristic of a physical link, and the delay of a protocol stack, of the X2 interface. If the base stations are connected by a high-capacity physical link, e.g., connected directly by an optic fiber, then there is a high information transmission rate via the X2 interface (e.g., at the order of 1 Gbps). If the base stations are connected by a low-capacity physical link, e.g., a radio transmission link, then there is a low information transmission rate via the X2 interface (e.g., 1 Mbps or lower). The delay via the X2 interface arises primarily from the delay of the physical layer transmission, and the delay of the protocol stack and may be up to 10 ms or more. There may be a variety of physical connection modes of the X2 interface in a practical network, and information shall be exchanged between the base stations in CoMP coordinated scheduling by taking a non-ideal X2 interface into account. Downlink coordinated multi-point transmission is realized based upon Channel State Information (CSI) obtained by the base stations, and the CSI are information of the channels from the UE to the respective transmission points. The CSI information includes Channel Quality Indicator (CQI) information, Pre-coding Matrix Indicator (PMI) information, Rank Indicator (RI) information, etc. The UE measures information of the channels from the respective base stations to the UE by using downlink reference signals transmitted by the base stations, and feeds the channel state information measured by the UE to a serving cell of the UE. The serving cell of the UE receives the fed-back CSI information and performs coordinated scheduling and/or coordinated pre-coding with the cooperating cells, to thereby enable coordinated transmission. Schemes of coordinated scheduling and/or coordinated pre-coding between the cells can be categorized into centralized coordinated scheduling and distributed coordinated scheduling. Centralized coordinated scheduling generally includes the following operations: A. The respective cooperating base stations transmit the received CSI information of all the UEs accessing the respective base stations to a Central Coordination Node (CCN); B. The CCN centrally schedules time and frequency resources for all the UEs of the cooperating base stations, and calculates pre-coding for the UEs for which the time and frequency resources are scheduled; C. The CCN transmits scheduling and pre-coding results of the respective UEs to the respective related base stations; and D. The base stations transmit data for the UEs according to the received scheduling and pre-coding results. In the centralized coordinated scheduling scheme, the scheduling CCN may perform global optimized scheduling for all the UEs in the cooperation set according to the global CSI information, to thereby achieve an ideal cooperation gain. However as demonstrated in the operations of centralized coordinated scheduling, centralized coordinated scheduling requires the cooperating base stations to transmit the CSI information of all the accessing UEs to the CCN, and the CCN needs to transmit all the scheduling results respectively to the respective base stations after scheduling, as illustrated in FIG. 1 . Transmission needs to be performed at least twice between the CCN and the base stations, so that with respect to a non-ideal X2 port connection, there may be a significant delay for the transmission via the X2 port, thus resulting in a considerable scheduling delay and a loss of transmission performance. A general principle of distributed coordinated scheduling lies in that the respective cooperating base stations schedule respectively; and the cooperating base stations cooperate by exchanging the scheduling information, the CSI information of the scheduled UEs, etc. From the perspective of the principle, distributed coordinated scheduling is performed respectively at the respective cooperating base stations without exchanging a large amount of CSI information via the X2 interface, so that there is a less amount of information transmitted via the X2 interface than in centralized coordinated scheduling, as illustrated in FIG. 2 . However, distributed coordinated scheduling can not optimize a global scheduling result according to scheduling conditions between the base stations. In order to achieve a nearly globally-optimized result, iterative scheduling between the base stations may need to be performed, so that the cooperating base stations may need to exchange the scheduling information with each other repeatedly. If there is a significant delay via the X2 interface between the base stations, then repeated exchanges of the scheduling information in distributed coordinated scheduling may come with such a high scheduling delay that the channel information may become outdated, thus degrading the transmission performance Thus, the scheme of CoMP distributed coordinated scheduling needs to be designed carefully in the scenario with a significant delay via the X2 interface, to thereby minimize the number of times that the information is exchanged between the cooperating base stations, to thereby lower the amount of exchanged information. In summary, there is such a large amount of information exchanged between the base stations in the existing scheme of CoMP centralized coordinated scheduling that there may be a significant loss of the system performance, if the scheme is implemented by using a non-ideal link of the X2 interface; and the scheduling information needs to be exchanged iteratively in iterative distributed coordinated scheduling, so that there will be a considerable increase in transmission delay via the X2 interface with a significant delay. SUMMARY Embodiments of the present disclosure provide a method and device for scheduling resources in coordinated multi-point transmission, so as to reduce the delay in the scheme of centralized coordinated scheduling for CoMP, so as to improve the efficiency of scheduling. A method for scheduling resources in CoMP transmission, includes: receiving, by a serving base station, CSI reported by UEs, and determining resulting pre-coding matrixes prohibited from being used by a cooperating base station, according to a result of pre-negotiation with the cooperating base station; and performing, by the serving base station, resource scheduling, according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling, according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a delay of transmission via an X2 interface between the serving base station and the cooperating base station, and thus improve the efficiency of scheduling. Preferably before the serving base station receives the CSI reported by the UEs, the method further includes: determining, by the serving base station, pre-coding matrixes requested for being prohibited from being used by the cooperating base station, and sending to the cooperating base station an indicator of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station; and receiving, by the serving base station, an indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and determining the resulting pre-coding matrixes prohibited from being used by the cooperating base station according to the indicator, wherein the cooperating base station determines the resulting pre-coding matrixes prohibited from being used by the cooperating base station in such a way that: the cooperating base station determines a set of candidate prohibited pre-coding matrixes, according to CSI reported by the UEs; determines the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station according to the indicator, sent by the serving base station, of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station; and determine pre-coding matrixes in an intersection of the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, and the set of candidate prohibited pre-coding matrixes as the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Determining, by the serving base station, the pre-coding matrixes requested for being prohibited from being used by the cooperating base station may include but will not be limited to: determining, by the serving base station, a downlink transmission performance index of each UE served by the serving base station respectively according to the CSI of the serving base station reported by the corresponding UE, and searching the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the highest transmission performance; and determining a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, wherein the PMI or PMIs of the cooperating base station are reported by a CoMP UE or UEs corresponding to the found downlink transmission performance index or indexes. Here sending, by the serving base station, to the cooperating base station the indicator of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station may include but will not be limited to: sending, by the serving base station, at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, wherein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Preferably the indicator, transmitted by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station includes at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, wherein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Further to any one of the embodiments above of the present disclosure, preferably performing, by the serving base station, resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station may include but will not be limited to: determining, by the serving base station, interference to downlink transmission of the UEs served by the serving base station, according to the resulting pre-coding matrixes prohibited from being used by the cooperating base station, wherein the interference does not contain interference generated when the resulting pre-coding matrixes prohibited from being used by the cooperating base station are used by the cooperating base station; and scheduling, by the serving base station, resources for the UEs served by the serving base station, according to the interference to downlink transmission of the UEs served by the serving base station, and the received CSI. Further to any one of the embodiments above of the present disclosure, preferably after the serving base station performs resource scheduling, the method further may include but will not be limited to: informing, by the serving base station, to the cooperating base station whether the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over a scheduling resource, according to a result of scheduling the resource. Furthermore informing, by the serving base station, to the cooperating base station whether the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource, according to the result of scheduling the resource includes: if the serving base station does not schedule any CoMP UE over the scheduling resource, then informing the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; and if the serving base station schedules a CoMP UE over the scheduling resource, then informing the cooperating base station that the cooperating base station is not allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; or not informing the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource. A method for scheduling resources in CoMP transmission includes: receiving, by a cooperating base station, CSI reported by each UE, and determining resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to a result of pre-negotiating with a serving base station; performing, by the cooperating base station, resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station and thus improve the efficiency of scheduling. Preferably before the cooperating base station receives the CSI reported by the UEs, the method further includes: determining, by the cooperating base station, a set of candidate prohibited pre-coding matrixes according to the CSI reported by the UEs; and receiving, by the cooperating base station, an indicator, sent by the serving base station, of pre-coding matrixes requested for being prohibited from being used by the cooperating base station; determining a set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, according to the indicator; determining pre-coding matrixes in an intersection of the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, and the set of candidate prohibited pre-coding matrixes as the resulting pre-coding matrixes prohibited from being used by the cooperating base station; and sending an indicator of the resulting pre-coding matrixes prohibited from being used by the cooperating base station to the serving base station. Here the indicator, sent by the serving base station, of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station includes at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, and a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Preferably determining, by the cooperating base station, the set of candidate prohibited pre-coding matrixes according to the CSI reported by the UEs includes: determining, by the cooperating base station, a downlink transmission performance index of each UE served by the cooperating base station respectively according to the CSI of the cooperating base station reported by the corresponding UE; and searching the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the lowest transmission performance, and determining a set including a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as the set of candidate prohibited pre-coding matrixes, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes; or searching the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the highest transmission performance, and determining a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as pre-coding matrixes which are not allowed to be prohibited, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes, and determining a set including the other pre-coding matrixes than the pre-coding matrixes which are not allowed to be prohibited, as the set of candidate prohibited pre-coding matrixes. Preferably sending, by the cooperating base station, the indicator of the resulting pre-coding matrixes prohibited from being used by the cooperating base station to the serving base station includes: sending, by the cooperating base station, at least one PMI, and information about relevance range of each of the at least one PMI to the serving base station, wherein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Preferably performing, by the cooperating base station, resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station includes: determining, by the cooperating base station, whether any notification, transmitted by the serving base station and the other respective cooperating base stations, indicating that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over a scheduling resource, has been received; and if so, then performing resource scheduling according to the CSI reported by the UEs; otherwise, performing resource scheduling according to the CSI reported by the UEs, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. A serving base station includes: a first receiving unit configured to receive CSI reported by each UE; a first determining unit configured to determine resulting pre-coding matrixes prohibited from being used by a cooperating base station, according to a result of pre-negotiation with the cooperating base station; and a scheduling unit configured to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station and thus improve the efficiency of scheduling. Preferably the serving base station further includes: a second determining unit configured to determine pre-coding matrixes requested for being prohibited from being used by the cooperating base station; a sending unit configured to send to the cooperating base station an indicator of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station; and a third determining unit configured to receive an indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and to determine the resulting pre-coding matrixes prohibited from being used by the cooperating base station according to the indicator, wherein the cooperating base station determines the resulting pre-coding matrixes prohibited from being used by the cooperating base station by determining a set of candidate prohibited pre-coding matrixes according to CSI reported by each UE; determining the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station according to the indicator, sent by the serving base station, of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station; and determining pre-coding matrixes in an intersection of the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, and the set of candidate prohibited pre-coding matrixes as the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Preferably the second determining unit is configured: to determine a downlink transmission performance index of each UE served by the serving base station respectively according to the CSI of the serving base station reported by the corresponding UE, and to search the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the highest transmission performance; and to determine a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, wherein the PMI or PMIs of the cooperating base station are reported by a CoMP UE or UEs corresponding to the found downlink transmission performance index or indexes. Preferably the sending unit is configured: to send at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, wherein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Preferably the third determining unit is configured: to receive the indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station, wherein the indicator includes at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, and a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Further to any one of the embodiments above of the serving base station, preferably the scheduling unit is configured: to determine interference to downlink transmission of the UEs served by the serving base station, according to the resulting pre-coding matrixes prohibited from being used by the cooperating base station, wherein the interference does not contain interference generated when the resulting pre-coding matrixes prohibited from being used by the cooperating base station are used by the cooperating base station; and to schedule resources for the UEs served by the serving base station, according to the interference to downlink transmission of the UEs served by the serving base station, and the received CSI. Further to any one of the embodiments above of the serving base station, preferably the serving base station further includes: an informing unit configured to inform the cooperating base station whether the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over a scheduling resource, according to the result of scheduling the resource after resource scheduling is performed. Preferably the informing unit is configured: after resource scheduling is performed, if there is not any CoMP UE over the scheduling resource, to inform the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; otherwise, to inform the cooperating base station that the cooperating base station is not allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; or not to inform the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource. Based upon the same inventive idea as the method, an embodiment of the present disclosure provides another serving base station including a radio frequency unit and a processor, wherein: the radio frequency unit is configured to receive CSI reported by each UE; and the processor is configured to determine resulting pre-coding matrixes prohibited from being used by a cooperating base station, according to a result of pre-negotiation with the cooperating base station; and to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station and thus improve the efficiency of scheduling. A cooperating base station includes: a receiving unit configured to receive CSI reported by each UE; a first determining unit configured to determine resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to a result of pre-negotiating with a serving base station; a scheduling unit configured to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station to thereby perform subsequent resource scheduling according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station and thus improve the efficiency of scheduling. Preferably the cooperating base station further includes: a second determining unit configured to determine a set of candidate prohibited pre-coding matrixes according to the CSI reported by the UEs; a third determining unit configured to receive an indicator, sent by the serving base station, of pre-coding matrixes requested for being prohibited from being used by the cooperating base station; and to determine a set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, according to the indicator; a fourth determining unit configured to determine pre-coding matrixes in an intersection of the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, and the set of candidate prohibited pre-coding matrixes as the resulting pre-coding matrixes prohibited from being used by the cooperating base station; and a sending unit configured to send an indicator of the resulting pre-coding matrixes prohibited from being used by the cooperating base station to the serving base station. Preferably the third determining unit is configured: to receive the indicator, sent by the serving base station, of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, wherein the indicator includes at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, and a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Preferably the second determining unit is configured: to determine a set of candidate prohibited pre-coding matrixes, and particularly the cooperating base station determines a downlink transmission performance index of each UE served by the cooperating base station respectively according to the CSI of the cooperating base station reported by the corresponding UE; and to search the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the lowest transmission performance, and to determine a set including a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as the set of candidate prohibited pre-coding matrixes, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes; or to search the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the highest transmission performance, and to determine a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as pre-coding matrixes which are not allowed to be prohibited, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes, and to determine a set including the other pre-coding matrixes than the pre-coding matrixes which are not allowed to be prohibited, as the set of candidate prohibited pre-coding matrixes. Preferably the sending unit is configured: to send at least one PMI, and information about relevance range of each of the at least one PMI to the serving base station, wherein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Preferably the scheduling unit is configured: to determine whether any notification, transmitted by the serving base station and the other respective cooperating base stations, indicating that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over a scheduling resource, has been received; and if so, to perform resource scheduling according to the CSI reported by the UEs; otherwise, to perform resource scheduling according to the CSI reported by the UEs, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Based upon the same inventive idea as the method, an embodiment of the present disclosure provides another serving base station including a radio frequency unit and a processor, wherein: the radio frequency unit is configured to receive CSI reported by each UE; and the processor is configured to determine resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to a result of pre-negotiating with a serving base station; and to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station and thus improve the efficiency of scheduling. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a schematic diagram of information exchanging in centralized scheduling in the prior art; FIG. 2 illustrates a schematic diagram of information exchanging in distributed scheduling in the prior art; FIG. 3 illustrates a schematic flow chart of a method according to an embodiment of the present disclosure; FIG. 4 illustrates a schematic flow chart of another method according to an embodiment of the present disclosure; FIG. 5A illustrates a schematic flow chart according to a first embodiment of the present disclosure; FIG. 5B illustrates a schematic flow chart according to a second embodiment of the present disclosure; FIG. 6 illustrates a schematic diagram of a serving base station according to an embodiment of the present disclosure; and FIG. 7 illustrates a schematic diagram of a cooperating base station according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS In order to lower a delay in the scheme of distributed coordinated scheduling in CoMP transmission, to thereby improve the efficiency of scheduling, embodiments of the present disclosure provide a method for scheduling resources in CoMP transmission. Referring to FIG. 3 , a method for scheduling resources in CoMP transmission, according to an embodiment of the present disclosure includes the following operations: Operation 30 : A serving base station receives CSI reported by UEs, and determines resulting pre-coding matrixes prohibited from being used by a cooperating base station, according to a result of pre-negotiation with the cooperating base station, herein the CSI reported by the UEs may include one or any combination of a PMI, an RI and a CQI; and Operation 31 : The serving base station performs resource scheduling, according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Data may be transmitted to the UE, according to a result of resource scheduling after resource scheduling is performed in the flow illustrated in FIG. 3 . Before the operation 30 , the serving base station may pre-negotiate with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, particularly in the following operation A to operation B without any limitation thereto: Operation A: the serving base station determines pre-coding matrixes requested for being prohibited from being used by the cooperating base station, and sends to the cooperating base station an indicator of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station; Herein, the serving base station may determine the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, in a number of implementations, particularly as follows: The serving base station determines a downlink transmission performance index of each UE served by the serving base station respectively, according to the CSI of the serving base station reported by the corresponding UE, searches the downlink transmission performance index of each UE for one or more downlink transmission performance indexes indicating the highest transmission performance, and determines a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs, as the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, wherein the PMI or PMIs of the cooperating base station are reported by a CoMP UE or CoMP UEs corresponding to the found downlink transmission performance index or indexes. Here the downlink transmission performance index may include a throughput, a fairness weight or other data capable of reflecting downlink transmission performance; and the pre-coding matrix in the relevance range of the PMI refers to a pre-coding matrix, with a relevance, lying in the relevance range, to the pre-coding matrix corresponding to the PMI, for example, the relevance range may be a preset value, and a pre-coding matrix, with a relevance, no less or more than the preset value, to the pre-coding matrix corresponding to the PMI, may be determined as a pre-coding matrix in the relevance range of the PMI; and in another example, the relevance range may be a value interval, and a pre-coding matrix, with a relevance lying within or outside the value interval, may be determined as a pre-coding matrix in the relevance range of the PMI. The serving base station may send to the cooperating base station the indicator of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, in a number of implementations, particularly as follows: The serving base station sends at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, herein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each of the at least one PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Operation B: the serving base station receives an indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and determines the resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to the indicator; and the resulting pre-coding matrixes prohibited from being used by the cooperating base station is determined by the cooperating base station as follows: the cooperating base station determines a set of candidate prohibited pre-coding matrixes according to the CSI reported by the UEs; determines a set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, according to an indicator, sent by the serving base station, of pre-coding matrixes requested for being prohibited from being used by the cooperating base station, and determines pre-coding matrixes in an intersection of the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, and the set of candidate prohibited pre-coding matrixes as the resulting pre-coding matrixes prohibited from being used by the cooperating base station. The indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station may include but will not be limited to at least one PMI, and information about relevance range of each of the at least one PMI, herein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station; and correspondingly, the serving base station determines the resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to the indicator particularly as follows: the serving base station determines the pre-coding matrix corresponding to the at least one PMI, and the pre-coding matrix in the relevance range of each PMI, as the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Particularly in the operation 31 , the serving base station may perform resource scheduling, according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station in a number of implementations, particularly as follows: The serving base station determines interference to downlink transmission of the UEs served by the serving base station, according to the resulting pre-coding matrixes prohibited from being used by the cooperating base station, herein the interference does not contain interference generated when the resulting pre-coding matrixes prohibited from being used by the cooperating base station are used by the cooperating base station; and The serving base station schedules resources for the UEs served by the serving base station, according to the interference to downlink transmission of the UEs served by the serving base station, and the received CSI. Further to any of embodiments of the method, after the serving base station performs resource scheduling, the serving base station may inform the cooperating base station whether the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resources, according to the result of scheduling the resources in a number of implementations, particularly as follows: If the serving base station does not schedule any CoMP UE over the scheduling resources, then the serving base station informs the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resources; and if the serving base station has scheduled a CoMP UE over the scheduling resources, then the serving base station informs the cooperating base station, that the cooperating base station is not allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resources, or does not inform the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resources. Referring to FIG. 4 , an embodiment of the present disclosure provides a method for scheduling resources in CoMP transmission, the method includes the following operations: Operation 40 : A cooperating base station receives CSI reported by UEs and determines resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to a result of pre-negotiating with a serving base station, and the CSI reported by the UEs may include one or any combination of a PMI, an RI and a CQI; and Operation 41 : The cooperating base station performs resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Data may be transmitted to the UE according to a result of resource scheduling, after resource scheduling is performed in the flow illustrated in FIG. 4 . Before the operation 40 , the cooperating base station may pre-negotiate with the serving base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, in a number of implementations, particularly in the following operation C to operation D: C. The cooperating base station determines a set of candidate prohibited pre-coding matrixes according to the CSI reported by the UEs; Here the cooperating base station may determine the set of candidate prohibited pre-coding matrixes according to the CSI reported by the UEs, in a number of implementations, particularly as follows: The cooperating base station determines a downlink transmission performance index of each UE served by the cooperating base station respectively, according to the CSI of the cooperating base station reported by the corresponding UE; and The cooperating base station searches the downlink transmission performance indexes of the respective UEs, for one or more downlink transmission performance indexes indicating the lowest transmission performance, and determines a set including a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs, as the set of candidate prohibited pre-coding matrixes, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes; or searches the downlink transmission performance indexes of the respective UEs, for one or more downlink transmission performance indexes indicating the highest transmission performance, and determines a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs, as pre-coding matrixes which are not allowed to be prohibited, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes, and determines a set including the other pre-coding matrixes than the pre-coding matrixes which are not allowed to be prohibited, as the set of candidate prohibited pre-coding matrixes. Here the downlink transmission performance index may include a throughput, a fairness weight or other data capable of reflecting downlink transmission performance; the pre-coding matrix in the relevance range of the PMI refers to a pre-coding matrix, with a relevance lying in the relevance range to the pre-coding matrix corresponding to the PMI, for example, the relevance range may be a preset value, and a pre-coding matrix, with a relevance, no less or more than the preset value, to the pre-coding matrix corresponding to the PMI, may be determined as a pre-coding matrix in the relevance range of the PMI; and in another example, the relevance range may be a value interval, and a pre-coding matrix, with a relevance, lying within or outside the value interval, may be determined as a pre-coding matrix in the relevance range of the PMI. D. The cooperating base station receives an indicator, sent by the serving base station, of pre-coding matrixes requested for being prohibited from being used by the cooperating base station, determines a set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, according to the indicator; determines pre-coding matrixes in an intersection of the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, and the set of candidate prohibited pre-coding matrixes, as the resulting pre-coding matrixes prohibited from being used by the cooperating base station; and sends an indicator of the resulting pre-coding matrixes prohibited from being used by the cooperating base station to the serving base station. Here the indicator, sent by the serving base station, of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station may include at least one PMI, and information about relevance range of each of the at least one PMI, herein the pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station; and correspondingly, the cooperating base station determines the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, according to the indicator particularly as follows: the cooperating base station determines a set including the pre-coding matrix corresponding to the at least one PMI, and the pre-coding matrix in the relevance range of each PMI, as the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. The cooperating base station may send the indicator of the resulting pre-coding matrixes prohibited from being used by the cooperating base station to the serving base station, in a number of implementations, particularly as follows: the cooperating base station sends at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, herein a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station. The cooperating base station may perform resource scheduling, according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station in the operation 41 , in a number of implementations, particularly as follows: The cooperating base station determines whether any notification, transmitted by the serving base station and the other respective cooperating base stations, indicating that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resources, has been received; and if the notification has been received, then the cooperating base station performs resource scheduling according to the CSI reported by the UEs, that is, performs resource scheduling as in the prior art; if the notification has not been received, the cooperating base station performs resource scheduling, according to the CSI reported by the UEs, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and particularly, the cooperating base station does not use the resulting pre-coding matrixes prohibited from being used, to schedule any resources, and the cooperating base station does not use the resulting pre-coding matrixes prohibited from being used, for downlink transmission, that is, the cooperating base station performs resource scheduling, according to the CIS reported by the UEs, by using the other pre-coding matrixes than the resulting pre-coding matrixes prohibited from being used by the cooperating base station. An interaction flow between the present serving base station and the cooperating base station will be described below in details as illustrated in FIG. 5A : Operation 1 : The serving base station receives CSI reported by UEs served by the serving base station, and negotiates with the cooperating base station about pre-coding matrixes which can be used and/or which are prohibited from being used by the cooperating base station. The CSI reported by the CoMP UEs at least includes PMI information of the cooperating base station, and PMI/RI and CQI information of the serving base station. Herein the CoMP UEs refer to UEs to which a plurality of base stations cooperate in transmitting. As illustrated in FIG. 5B , the serving base station may negotiate with the cooperating base station about resulting pre-coding matrixes prohibited from being used by the cooperating base station in the following operations 101 to 106 : Operation 101 : The cooperating base station determines a set of candidate prohibited pre-coding matrixes, and particularly the cooperating base station determines a downlink transmission performance index (e.g. throughput) of each UE served by the cooperating base station respectively according to CSI (e.g., PMI/RI and CQI information) of the cooperating base station reported by the corresponding UE; and searches the downlink transmission performance indexes of the respective UEs, for one or more downlink transmission performance indexes indicating the lowest transmission performance, and determines a set including a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as the set of candidate prohibited pre-coding matrixes, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes; or searches the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the highest transmission performance, and determines a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs, as pre-coding matrixes which are not allowed to be prohibited, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes, and determines a set including the other pre-coding matrixes than the pre-coding matrixes which are not allowed to be prohibited, as the set of candidate prohibited pre-coding matrixes. Operation 102 : The serving base station determines pre-coding matrixes requested for being prohibited from being used by the cooperating base station, and particularly the serving base station determines a downlink transmission performance index (e.g. throughput) of each UE served by the serving base station respectively, according to the CSI (e.g., PMI/RI and CQI information) of the serving base station reported by the corresponding UE, searches the downlink transmission performance indexes of the respective UEs, for one or more downlink transmission performance indexes indicating the highest transmission performance, and determines a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs, as the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, wherein the PMI or PMIs of the cooperating base station are reported by a CoMP UE or UEs corresponding to the found downlink transmission performance index or indexes. Operation 103 : The serving base station sends to the cooperating base station an indicator of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station. For example, the indicator includes at least one PMI, and information about relevance range of each of the at least one PMI, and a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Operation 104 : The cooperating base station receives the indicator, sent by the serving base station, of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, and determines a set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station according to the indicator, and particularly the cooperating base station determines a set including the pre-coding matrix corresponding to the at least one PMI in the indicator, and the a pre-coding matrix in the relevance range of each PMI, as the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Operation 105 : The cooperating base station determines the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and particularly, the cooperating base station determines pre-coding matrixes in an intersection of the set of pre-coding matrixes prohibited from being used by the cooperating base station, determined in the operation 104 , and the set of candidate prohibited pre-coding matrixes, determined in the operation 101 , as the resulting pre-coding matrixes prohibited from being used by the cooperating base station. The cooperating base station sends an indicator of the resulting pre-coding matrixes prohibited from being used by the cooperating base station to the serving base station. For example, the indicator includes at least one PMI, and information about relevance range of each of the at least one PMI; and a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Operation 106 : The serving base station receives the indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and determines and records the resulting pre-coding matrixes prohibited from being used by the cooperating base station according to the indicator, to thereby perform resource scheduling according to the recorded resulting pre-coding matrixes prohibited from being used by the cooperating base station in subsequent resource scheduling. The serving base station may negotiate with the cooperating base station about the pre-coding matrixes prohibited from being used in the operations above uniformly for the entire transmission bandwidth, so that the result of negotiation is valid to the entire bandwidth; or they may negotiate separately for each scheduling resource, so that the result of negotiation on each scheduling resource is valid only to the scheduling resource. Relative to resource scheduling by the base stations, the serving base station may semi-statically negotiate with the cooperating base station about the pre-coding matrixes prohibited from being used, and need to perform the above negotiation procedure every time before resource scheduling, and a result of negotiation between the base stations will be valid for a period of time until a new result of negotiation is generated in next negotiation between the base stations. Operation 2 : The serving base station receives CSI reported by UEs served by the serving base station, performs resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station, recorded in the operation 1 , and transmits data to the UE according to a result of resource scheduling. Here resource scheduling is performed as follows: if the cooperating base station does not use the pre-coding matrixes prohibited from being used by the cooperating base station over resources, then serving base station schedules the resources, and calculates pre-coding matrixes, for the UEs, and particularly the serving base station determines interference to downlink transmission of the UEs served by the serving base station, according to the resulting pre-coding matrixes prohibited from being used by the cooperating base station, herein the interference does not contain interference generated when the resulting pre-coding matrixes prohibited from being used by the cooperating base station are used by the cooperating base station; and schedules resources for the UEs served by the serving base station, according to the interference to downlink transmission of the UEs served by the serving base station, and the received CSI. Operation 3 : The serving base station informs the cooperating base station whether the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over each scheduling resource, according to the result of scheduling the scheduling resource. Particularly if the serving base station does not schedule any CoMP UE over a scheduling resource, then the serving base station informs the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; otherwise, the serving base station does inform the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; and the notification that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource, can be valid for a length of time prescribed by the serving base station with the cooperating base station, e.g., one or several sub-frames, and the period of time for which the notification is valid may be further transmitted to the cooperating base station in the form of the length of valid time, starting and ending points of valid time, etc., together with the notification, and the notification may be embodied in the form of a bitmap in which each bit corresponds to one of the scheduling resources, and the sequence of scheduling the resources in the bitmap is prescribed between the base stations, the serving base station sets bits, corresponding to scheduling resources over which the cooperating base station is allowed to use the pre-coding matrixes prohibited from being used, to be 1, and bits corresponding to the other scheduling resources to be 0; and the notification may further include directly sequence number of the scheduling resources over which the cooperating base station is allowed to use the pre-coding matrixes prohibited from being used; Operation 4 : The cooperating base station determines, for each scheduling resource, whether the resulting pre-coding matrixes prohibited from being used by the cooperating base station can be used over the corresponding scheduling resource, according to the received notification particularly as follows: with respect to a scheduling resource, if all the other cooperating base stations (including the serving base station) transmit, to the cooperating base station, a notification that the cooperating base station is allowed to use the pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource, then it is determined that the resulting pre-coding matrixes prohibited from being used by the cooperating base station can be used over the scheduling resource; otherwise, it is determined that the resulting pre-coding matrixes prohibited from being used by the cooperating base station can not be used over the scheduling resource; Operation 5 : The cooperating base station performs resource scheduling, according to a result of the determination in the operation 4 , in the period of time for which the notification is valid after making the determination in the operation 4 . Particularly, if it is determined that the resulting pre-coding matrixes prohibited from being used by the cooperating base station can be used over a scheduling resource, then the cooperating base station performs resource scheduling according to the CSI reported by the UEs, that is, performs resource scheduling as in the prior art; otherwise, the cooperating base station performs resource scheduling, according to the CSI reported by the UEs, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station, that is, the cooperating base station does not use the resulting pre-coding matrixes prohibited from being used, to schedule the resources, and does not use the resulting pre-coding matrixes prohibited from being used, in downlink transmission; and Operation 6 : The cooperating base station transmits data to the UE according to a result of resource scheduling. An embodiment of the scheme of distributed coordinated scheduling is as follows: Firstly the system is assumed as follows: There are two base stations in the system: a base station 1 and a base station 2 cooperate in CS/CB transmission; The two base stations have two scheduling resources including a scheduling resource 1 and a scheduling resource 2 ; The base station 1 serves two UEs, including a UE 1 and a UE 2 , which may be scheduled over the two scheduling resources, herein the UE 1 is a CoMP UE, and the UE 2 is not a CoMP UE; and the base station 2 also serves two UE 2 , including a UE 3 and a UE 4 , herein the UE 3 is a CoMP UE, and the UE 4 is not a CoMP UE. At this time a distributed CS/CB information exchange procedure over the network is as follows: a. If the UE 1 reports that broadband PMIs of the base station 1 and the base station 2 respectively are PMI 11 and PMI 12 ; the UE 2 reports that a broadband PMI of the base station 1 is PMI 21 ; the UE 3 reports that broadband PMIs of the base station 2 and the base station 1 respectively are PMI 32 and PMI 31 ; and the UE 4 reports that a broadband PMI of the base station 2 is PMI 42 , then the base station 1 determines pre-coding matrixes with relevancies, no more than 0.5, to both the PMI 11 and the PMI 21 , as candidate prohibited pre-coding matrixes of the base station 1 in the entire bandwidth, and the base station 2 determines pre-coding matrixes with relevancies, no more than 0.5, to both the PMI 32 and the PMI 42 , as candidate prohibited pre-coding matrixes of the base station 2 in the entire bandwidth. The base station 1 determines the PMI of the base station 2 reported by the UEs 1 , i.e., the PMI 12 , as a PMI requested for being prohibited by the base station 2 in the entire bandwidth; and the base station 2 determines the PMI of the base station 1 reported by the UEs 3 , i.e., the PMI 31 , as a PMI requested for being prohibited by the base station 1 in the entire bandwidth. b. The base station 1 notifies the base station 2 of the PMI requested for being prohibited by the base station 2 in the entire bandwidth, i.e., the PMI 12 , and the base station 2 notifies the base station 1 of the PMI requested for being prohibited by the base station 1 in the entire bandwidth, i.e., the PMI 31 . The base station 1 receives the PMI 31 , determines pre-coding matrixes with relevancies, no less than 0.5, to the PMI 31 , as a set of pre-coding matrixes requested by the base station 2 for being prohibited, and determines an intersection of the set of pre-coding matrixes requested by the base station 2 for being prohibited, and the set of candidate prohibited pre-coding matrixes of the base station 1 , obtained in the operation a as a set of pre-coding matrixes prohibited from being used, herein the set includes all of pre-coding matrixes with relevancies, no less than 0.8, to a PMI α . The base station 1 notifies the base station 2 of the PMI α and the relevancy of “0.8”, and the base station 2 records a set of pre-coding matrixes prohibited from being used by the base station as all the pre-coding matrixes with relevancies, no less than 0.8, to the PMI α . Similarly, the base station 2 determines all of pre-coding matrixes with relevancies, no less than 0.9, to a PMI β , as pre-coding matrixes prohibited from being used by the present base station, and informs the base station 1 the pre-coding matrixes prohibited from being used. c. The UEs 1 and 2 reports CSI information to the base station, and the base station 1 performs resource scheduling, and calculates pre-coding matrixes, for the UEs according to the reported CSI. When the base station 1 performs resource scheduling, it is assumed that the base station 2 does not use the pre-coding matrixes prohibited from being used by the base station 2 , and the UEs of the base station 1 do not use the pre-coding matrixes prohibited from being used by the base station 1 . It is assumed that the base station 1 schedules the UE 1 over the scheduling resource 1 using a pre-coding matrix W 11 , and W 11 does not belong to the set of pre-coding matrixes prohibited from being used by the base station 1 , and the base station 1 schedules the UE 2 over the scheduling resource 2 using a pre-coding matrix W 22 , and W 22 does not belong to the set of pre-coding matrixes prohibited from being used by the base station 1 ; and the base station 2 schedules the UE 3 over the scheduling resource 1 using a pre-coding matrix W 31 , and W 31 does not belong to the set of pre-coding matrixes prohibited from being used by the base station 2 , and the base station 1 schedules the UE 4 over the scheduling resource 2 using a pre-coding matrix W 42 , and W 42 does not belong to the set of pre-coding matrixes prohibited from being used by the base station 2 , as depicted In Table 1 below. TABLE 1 Scheduling resource 1 Scheduling resource 2 base base base base station 1 station 2 station 1 station 2 Pre-scheduled UE UE 1 UE 3 UE 2 UE 4 Pre-coding matrix W 11 W 31 W 22 W 42 d. The base station 1 does not schedule any CoMP UE over the scheduling resource 2 , and the base station 1 notifies the base station 2 of a resource sequence-number 2 and an allowed duration 1 , to indicate that the base station 2 can use the pre-coding matrixes prohibited from being used over the scheduling resource 2 in one sub-frame; and the base station 2 does not schedule any CoMP UE over the scheduling resource 2 either, and the base station 2 notifies the base station 1 of the resource sequence-number 2 and an allowed duration 2 , to indicate that the base station 1 can use the pre-coding matrixes prohibited from being used over the scheduling resource 2 in two sub-frames. e. The base station 1 receives the notification, transmitted by the base station 2 , that the pre-coding matrixes prohibited from being used can be used over the scheduling resource 2 , and performs resource scheduling, and calculates pre-coding matrixes, again on the scheduling resource 2 , and schedules the UE 2 and the UE 1 over the schedules after performing scheduling again, herein the pre-coding matrix of the UE 2 is W′ 22 , and W′ 22 belongs to the set of pre-coding matrixes prohibited from being used by the base station 1 , recorded by the present base station, and the pre-coding matrix of the UE 1 is W 12 . The base station receives the notification, transmitted by the base station 1 , that the pre-coding matrixes prohibited from being used can be used by the base station 2 , but does not perform resource scheduling again, as depicted in Table 2. TABLE 2 Scheduling resource 1 Scheduling resource 2 base base base base station 1 station 2 station 1 station 2 Pre-scheduled UE UE 1 UE 3 UE 2 UE 1 UE 4 Pre-coding matrix W 11 W 31 W 22 ′ W 12 W 42 Referring to FIG. 6 , an embodiment of the present disclosure provides a serving base station including: A first receiving unit 60 is configured to receive Channel State Information (CSI) reported by UEs; A first determining unit 61 is configured to determine resulting pre-coding matrixes prohibited from being used by a cooperating base station, according to a result of pre-negotiation with the cooperating base station; A scheduling unit 62 is configured to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used; and A transmitting unit 63 is configured to transmit data to the UE according to a result of resource scheduling. Furthermore the serving base station further includes: A second determining unit 64 is configured to determine pre-coding matrixes requested for being prohibited from being used by the cooperating base station; A sending unit 65 is configured to send to the cooperating base station an indicator of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station; and A third determining unit 66 is configured to receive an indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and to determine the resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to the indicator. Furthermore the second determining unit 64 is configured: To determine a downlink transmission performance index of each UE served by the serving base station respectively according to the CSI of the serving base station reported by the corresponding UE, to search the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the highest transmission performance, and to determine a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs, as the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, wherein the PMI or PMIs of the cooperating base station are reported by a CoMP UE or UEs corresponding to the found downlink transmission performance index or indexes. Furthermore the sending unit 65 is configured: To send at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, where a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Furthermore the third determining unit 66 is configured: To receive the indicator, sent by the cooperating base station, of the resulting pre-coding matrixes prohibited from being used by the cooperating base station, where the indicator includes at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station; and a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station; and To determine the pre-coding matrix corresponding to the at least one PMI, and the pre-coding matrix in the relevance range of each PMI, as the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Furthermore the scheduling unit 62 is configured: To determine interference to downlink transmission of the UEs served by the serving base station, according to the resulting pre-coding matrixes prohibited from being used by the cooperating base station, herein the interference does not contain interference generated when the resulting pre-coding matrixes prohibited from being used by the cooperating base station are used by the cooperating base station; and To schedule resources for the UEs served by the serving base station, according to the interference to downlink transmission of the UEs served by the serving base station, and the received CSI. Furthermore the serving base station further includes: A informing unit 67 is configured to inform the cooperating base station, whether the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over a scheduling resource, according to the result of scheduling the resource after resource scheduling is performed. Furthermore the informing unit is configured: After resource scheduling is performed, if there is not any CoMP UE over the scheduling resource, to inform the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; otherwise, to inform the cooperating base station that the cooperating base station is not allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource; or not to inform the cooperating base station that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over the scheduling resource. Based upon the same inventive idea as the method, an embodiment of the present disclosure further provides a serving base station including a radio frequency unit and a processor, where: The radio frequency unit is configured to receive CSI reported by each UE; and The processor is configured to determine resulting pre-coding matrixes prohibited from being used by a cooperating base station, according to a result of pre-negotiation with the cooperating base station; and to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station, and thus improve the efficiency of scheduling. Referring to FIG. 7 , an embodiment of the present disclosure provides a cooperating base station including: A receiving unit 70 is configured to receive CSI reported by each UE; A first determining unit 71 is configured to determine resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to a result of pre-negotiating with a serving base station; A scheduling unit 72 is configured to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station; and A transmitting unit 73 is configured to transmit data to the UE according to a result of resource scheduling. Furthermore the cooperating base station further includes: A second determining unit 74 is configured to determine a set of candidate prohibited pre-coding matrixes according to the CSI reported by the UEs; A third determining unit 75 is configured to receive an indicator, sent by the serving base station, of pre-coding matrixes requested for being prohibited from being used by the cooperating base station; and to determine a set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, according to the indicator; A fourth determining unit 76 is configured to determine pre-coding matrixes in an intersection of the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station, and the set of candidate prohibited pre-coding matrixes as the resulting pre-coding matrixes prohibited from being used by the cooperating base station; and A sending unit 77 is configured to send an indicator of the resulting pre-coding matrixes prohibited from being used by the cooperating base station to the serving base station. Furthermore the third determining unit 75 is configured: To receive the indicator, sent by the serving base station, of the pre-coding matrixes requested for being prohibited from being used by the cooperating base station, wherein the indicator includes at least one PMI, and information about relevance range of each of the at least one PMI to the cooperating base station, and a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station; and To determine a set including the pre-coding matrix corresponding to the at least one PMI, and the a pre-coding matrix in the relevance range of each PMI as the set of pre-coding matrixes requested by the serving base station for being prohibited from being used by the cooperating base station. Furthermore the second determining unit 74 is configured: To determine a set of candidate prohibited pre-coding matrixes, and particularly the cooperating base station determines a downlink transmission performance index of each UE served by the cooperating base station respectively according to the CSI of the cooperating base station reported by the corresponding UE; and To search the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the lowest transmission performance, and to determine a set including a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as the set of candidate prohibited pre-coding matrixes, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes; or to search the downlink transmission performance indexes of the respective UEs for one or more downlink transmission performance indexes indicating the highest transmission performance, and to determine a pre-coding matrix or pre-coding matrixes corresponding to a PMI or PMIs of the cooperating base station, and a pre-coding matrix or pre-coding matrixes in a relevance range or relevance ranges of the PMI or PMIs as pre-coding matrixes which are not allowed to be prohibited, wherein the PMI or PMIs of the cooperating base station are reported by the UE or UEs corresponding to the found downlink transmission performance index or indexes, and to determine a set including the other pre-coding matrixes than the pre-coding matrixes which are not allowed to be prohibited, as the set of candidate prohibited pre-coding matrixes. Furthermore the sending unit 77 is configured: To send at least one PMI, and information about relevance range of each of the at least one PMI to the serving base station, where a pre-coding matrix corresponding to the at least one PMI, and a pre-coding matrix in the relevance range of each PMI constitute the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Furthermore the scheduling unit 72 is configured: To determine whether any notification, transmitted by the serving base station and the other respective cooperating base stations, indicating that the cooperating base station is allowed to use the resulting pre-coding matrixes prohibited from being used by the cooperating base station over a scheduling resource, has been received; and if the notification has been received, to perform resource scheduling according to the CSI reported by the UEs; otherwise, to perform resource scheduling according to the CSI reported by the UEs, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. Based upon the same inventive idea as the method, an embodiment of the present disclosure further provides a cooperating base station including a radio frequency unit and a processor, where: The radio frequency unit is configured to receive CSI reported by each UE; and The processor is configured to determine resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to a result of pre-negotiating with a serving base station; and to perform resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station. In this solution, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling according to the result of negotiation, without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station, and thus improve the efficiency of scheduling. In summary, advantageous effects of the present disclosure are as follows: In the solutions according to the embodiments of the present disclosure, the serving base station receives CCSI reported by each UE, determines resulting pre-coding matrixes prohibited from being used by a cooperating base station, according to a result of pre-negotiation with the cooperating base station, performs resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and transmits data to the UE according to a result of resource scheduling; and the cooperating base station receives CSI reported by each UE, determines the resulting pre-coding matrixes prohibited from being used by the cooperating base station, according to the result of pre-negotiating with the serving base station, performs resource scheduling according to the received CSI, and the resulting pre-coding matrixes prohibited from being used by the cooperating base station, and transmits data to the UE according to a result of resource scheduling. Apparently in the solutions, the serving base station pre-negotiates with the cooperating base station about the resulting pre-coding matrixes prohibited from being used by the cooperating base station, to thereby perform subsequent resource scheduling according to the result of negotiation without exchanging information between the serving base station and the cooperating base station every time before resource scheduling is performed, to thereby lower a transmission delay via an X2 interface between the serving base station and the cooperating base station, thus, improve the efficiency of scheduling. The present disclosure has been described in a flow chart and/or a block diagram of the method, the device (system) and the computer program product according to the embodiments of the present disclosure. It shall be appreciated that respective flows and/or blocks in the flow chart and/or the block diagram and combinations of the flows and/or the blocks in the flow chart and/or the block diagram can be embodied in computer program instructions. These computer program instructions can be loaded onto a general-purpose computer, a specific-purpose computer, an embedded processor or a processor of another programmable data processing device to produce a machine so that the instructions executed on the computer or the processor of the other programmable data processing device create means for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. These computer program instructions can also be stored into a computer readable memory capable of directing the computer or the other programmable data processing device to operate in a specific manner so that the instructions stored in the computer readable memory create an article of manufacture including instruction means which perform the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. These computer program instructions can also be loaded onto the computer or the other programmable data processing device so that a series of operational operations are performed on the computer or the other programmable data processing device to create a computer implemented process so that the instructions executed on the computer or the other programmable device provide operations for performing the functions specified in the flow(s) of the flow chart and/or the block(s) of the block diagram. Although the preferred embodiments of the present disclosure have been described, those skilled in the art benefiting from the underlying inventive concept can make additional modifications and variations to these embodiments. Therefore the appended claims are intended to be construed as encompassing the preferred embodiments and all the modifications and variations coming into the scope of the present disclosure. Evidently those skilled in the art can make various modifications and variations to the present disclosure without departing from the spirit and scope of the present disclosure. Thus the present disclosure is also intended to encompass these modifications and variations thereto so long as the modifications and variations come into the scope of the claims appended to the present disclosure and their equivalents.

The embodiments of the present application disclose a method and a device for scheduling a resource in coordinated multi-point transmission and relate to the field of the wireless communications, so as to reduce the delay of a non-center coordination scheduling solution under the coordinated multi-point CoMP transmission and improve the scheduling efficiency. The solution comprises: a serving base station determining, according to a preset result of a negotiation with a coordinated base station, a final precoding matrix the coordinated base station prohibits; scheduling a resource according to channel state information (CSI) reported by a user terminal and the final precoding matrix the coordinated base station prohibits, and the coordinated base station scheduling the resource according to the CSI reported by the user terminal and the final precoding matrix the coordinated base station prohibits. By using the solution, the efficiency of the resource scheduling can be improved.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a U.S. National Stage application of PCT/EP2015/068965 filed Aug. 18, 2015, which claims priority to German Application No. 10 2014 111 778.6 filed Aug. 18, 2014, the entire disclosures of which are hereby incorporated by reference in their entireties. TECHNICAL FIELD [0002] The invention relates to a method for monitoring the treatment of mobile patient support devices, for example, beds, stretchers, lifters, wheelchairs and wheeled walkers for use in clinical situations such as hospitals, acute clinical departments, rehabilitation facilities, care homes and other establishments where enhanced hygiene is necessary and treatment, i.e. cleaning and disinfecting, of mobile patient support devices is legally required. BACKGROUND [0003] Beds are used for different purposes in clinical situations. Whereas a bed for history taking and diagnosis of a patient often has the form of a couch, is used only briefly and that often only a little cleaning or the changing of the paper covering is required between patients, for prolonged or long-term admission and/or treatment of a patient, beds are needed which are legally defined as medical products and therefore are subject to high and strict hygiene standards which are regulated by law. [0004] The large number of existing beds and the high turnover rate of these beds in healthcare institutions result in elevated complexity in the administrative and treatment processes for these beds. In addition, beds are used by a wide range of patients with differing disease profiles and infection risks. [0005] In the clinical domain, beds can be divided into three categories which define an infection status of the bed: 1. “Clean bed”, i.e. disinfected and treated in accordance with the current regulations and available for re-use by a new patient—2. “Unclean bed”, i.e. following use by a patient without infection risk, awaiting disinfection and treatment—and 3. “Infected bed”, i.e. following use by a patient with an identified infection and thus a raised infection risk for the next patient, for personnel of the medical establishment and visitors, awaiting disinfection and treatment. [0006] Particularly “infected patients” who can transmit potential pathogens represent a high infection risk to other patients, clinical personnel and visitors. Therefore, each bed which can be classified as an “infected bed” should be identifiable. Infected beds should be clearly and unmistakeably identifiable in order to initiate suitable safety measures and so that a prescribed treatment process adapted to the high risk level can be carried out, including starting suitable occupational safety measures for the personnel. [0007] Careful handling of such potentially infected beds has a very great clinical relevance. In Germany, more than five percent of patients develop a hospital-associated infection and worldwide the average is over ten percent. Among the best known pathogens are, for example Pseudomonas aeruginosa, Clostridium difficile and Staphylococcus aureus. These microbes are however often to be eliminated by means of correct disinfection of all objects with which the affected patient has been in contact, and thus the associated risks of transmission are also contained. Due to the intensive and long-lasting contact with the patient, the bed therefore has a great significance. [0008] For the efficient, effective and ultimately safe treatment of clinical beds, in Germany and many other countries there are legal regulations which determine the type, scope and use of disinfectants and the time of exposure before re-use for the next patient. [0009] If these regulations are not, or are incompletely or incorrectly, carried out, this can therefore result in a much greater health risk for patients, clinical personnel and visitors if these pathogens are transmitted, for example, by contact with the contaminated bed and/or even develop a resistance, through transmission and mutation, against conventional antimicrobial, antimycotic or antiviral agents. Probably the best known hospital-associated infection results from such a mutation of Staphylococcus aureus following formation of a resistance to methicillin (MRSA). Throughout Germany, the annual number of microbial infections in hospitals is estimated to be over 500,000. In the field of inpatient care, it has also been shown that 20 percent of the clinical Staphylococcus aureus infections include MRSA. Other diseases which are transmissible, for example, by means of bodily fluids such as, for example, Herpes simplex virus (HSV), through blood, for example, human immunodeficiency virus (HIV), through skin contact, for example, human papilloma viruses (HPV), by ingestion, for example, norovirus or by aerogenic transmission, for example, Influenza viruses or Ebola naturally also require a specific disinfecting method to minimise the transmission risk. Faulty steps in the treatment process for a potentially infected bed can thus have serious consequences for patients, clinical personnel and visitors. [0010] The increased incidence of illnesses due to hospital-associated infection leads to a prolongation of the stay of a patient, a reduction in quality of life and a substantial increase in the costs to the healthcare system; the availability of hospital beds and medical care facilities is thus also negatively influenced. Not least, this leads to a heightened risk for the respective medical establishment of compensation claims by affected patients/clinical personnel/visitors. In addition, the reputation of the clinical establishment in question suffers. [0011] Depending on the circumstances of the hospital concerned or the circumstances of the administration, the nursing management and the housekeeping, unclean hospital beds are collected in rooms provided for the purpose either decentrally (on the ward) or centrally (the bed store) in order that the treatment/disinfection will be carried out at a later time. Often unclean beds remain in the ward in question or are “parked” in passageways or other freely accessible areas of the hospital until their transportation to the treatment area. It is herein clear that all unclean beds and particularly infected beds must be lastingly and unmistakeably identified. The lack of an unambiguous identification marker of an unclean and, in particular, an infected bed can lead thereto that infected beds are stored mixed together with normal soiled beds in one room. The resultant risk arises that infected beds are not recognised and are not made “harmless” with the disinfectants designated for infected beds. If, in addition, the type of the infection risk/the type of pathogen is unknown, then the bed treatment department also cannot set the required time of exposure of the respective designated disinfectant that is required so that the respective microbes can be completely killed. Infected beds can thus preferably also be identified according to the type of infection risk/pathogen so that in the treatment process both the disinfectant and also the time of exposure can be adhered to accordingly. If the type of infection risk is not stated, then the treatment process should always be based on the “worst case” as standard, i.e. the highest level of risk should be assumed. [0012] An identification of unclean beds as infected beds and the type of pathogen should take place no later than when the bed is fetched from a ward, in order to be able to initiate the correct, legally prescribed treatment process and the relevant occupational safety measures; for example, the packaging of the bedding into suitable plastic sacks, the visual identification of the bed as a potential risk to its surroundings, the putting on of personal protective equipment. These measures contribute thereto that the working safety of the staff is improved, while simultaneously reducing the risk of a spread of the pathogen and the endangering of further patients. [0013] Computer-assisted systems for bed management and thus for recording and amending a bed status between, for example, “free”, “occupied” or “to be collected” are known. There is, however, no method which, during the logging of a bed, simultaneously also records and documents its infection status and thus initiates a treatment process that is suitable and prescribed for this infection status. Currently, this is carried out very primitively through the provision of an infected bed with a docket, or orally on demand. This method does not solve the above mentioned problems and does not permit the establishment of resilient hygiene standards, because it is not testable and because, for example, the status is not recorded systematically, the status can become lost in the process or is no longer accessible and/or the status gives no notification of safety and treatment measures associated with the status. Thus, the medical establishment has no possibility for providing reliable evidence of, for example, which bed was an infected bed at which time point and which specific safety measures have been undertaken or whether and which possible risk for patients, personnel and visitors has been incurred. [0014] It is therefore an object of the present invention to provide a method which solves the above-mentioned problems and monitors the treatment process and makes it validatable—specifically overall as well as in individual steps—in order to ensure the legally required safety and hygiene standards, but also the respectively applicable industrial safety requirements. SUMMARY [0015] This object is solved by means of a method according to independent claim 1 and a system according to claim 16 . Advantageous developments are contained in the respective dependent claims. [0016] The solutions described below should not be read as relating exclusively to beds, rather they relate in general to every type of mobile patient support device, for example, also (mechanical) couches, stretchers, wheelchairs, rollators, lifters, chairs, operating tables, walking aids, shelves or other mechanical elements which can support a patient and can thus come into contact with him. [0017] The invention provides a method for monitoring the treatment of mobile patient support devices. Initially, the infection status of a mobile patient support device used by the patient is recorded in a database of a computer system. This mobile patient support device can also be identified at a treatment station through the identification of an identification indicator applied to the mobile patient support device by a data reader. At the treatment station, a notification can then be output concerning the infection status of the mobile patient support device. [0018] The infection status can be, for example, “clean”, “normal unclean” or “infected patient support device”. It is also possible, particularly in the case of the “infected patient support device” to undertake a more precise specification of, for example, the type of the pathogen. [0019] A treatment which can subsequently take place and is required by law on a change from one patient to the next is directed to the degree of contamination and potential infection risk. The strength of the effects and the time of exposure to the disinfectant agent are to be selected depending upon the infection status. Lists of disinfectant agents, the RKI and VAH lists, prescribed by the legislature serve as an aid during the selection and use of the suitable disinfectant agent. The treatment process always contains the substeps of cleaning and disinfection of the mobile patient support device. [0020] Such an inventive monitoring system offers the advantage, inter alia, that the person responsible for the treatment always receives a notification of the infection status of the patient support device. Thus, firstly, the safety of this person is ensured since he can protect himself according to the infection status, for example, by putting on protective clothing (PPE, personal protective equipment) and, secondly, the observance of the legally prescribed treatment is initiated in order to prevent the spread of potential pathogens. [0021] In a preferred embodiment, the infection status is recorded with a data reader, wherein the recording takes place by means of identifying an identification indicator applied to the mobile patient support device with the data reader. Either the infection status is automatically recorded in the database by means of the identification, or the infection status is input manually before or after the identification. The type of the infection risk can be input manually into the database subsequently. [0022] The recording of the infection status can take place, for example, by means of the physician responsible for the treatment, the nurses and/or the treatment personnel, wherein the respective person can also have a further identification indicator him/herself. Thus, the identification of a personal identification indicator before or after the recording of the infection status can also comprise proof of the decision of the respective responsible physician, the responsible nurse and/or the responsible treatment personnel. [0023] Particularly preferably, the recording of the infection status also leads, for example, to an automatic notification for collecting and/or treating the mobile patient support device, for example, to the collection and delivery service or the treatment personnel. [0024] An embodiment in which the recording of the infection status takes place automatically with the data reader offers the advantage that, in contrast to a manual input, the acquisition takes place with a single simple step of identification and is accordingly less fault-prone. At the same time, in a further preferred embodiment, a bundle of data/information relating to the mobile patient support device can be generated and stored, for example, in the database, such as performing personnel, location of the mobile patient support device, time and action and treatment step carried out. Thus, for example, a physician, a nurse and/or the treatment personnel can with a data reader in the form of a scanning device, with one action record both the infection status of the mobile patient support device and also initiate a notification regarding the collection and/or treatment. [0025] If the recording of the infection status does not take place with a data reader, the infection status can be acquired by means of a manual input, possibly after inquiry and/or retrospectively. It is herein particularly preferred that the infection status of the mobile patient support device, where this involves an infected bed/an infected patient support device, can be changed only after completion of the treatment. This has the advantage that an inadvertent interim identification of the identification indicator of the mobile patient support device and/or an omission of necessary treatment steps does not lead to a change in the infection status of the mobile patient support device and it is not unintentionally made available for renewed use by a new patient. [0026] In a further preferred embodiment, the mobile patient support device has at least two identification indicators which are assigned to different infection status levels, for example, “normal unclean” and “infected patient support device”. The data reader identifies one of the at least two identification indicators, specifically that which is assigned to the existing infection status. The infection status of the mobile patient support device can thus be acquired in the database of the computer system by identifying the corresponding identification indicator with the data reader, that is for example, for a normal contaminated mobile patient support device, the first identification indicator, and for a mobile patient support device at risk of infection, the second identification indicator. [0027] Particularly preferably, the different identification indicators are further configured to show the infection status visually. For this, these are configured, for example, in different colours, have a different pattern or are applied to a part of the mobile patient support device that identifies for the infection status. [0028] An embodiment which has different identification indicators has, inter alia, the advantage that it is possible to differentiate between the different contamination and/or infection levels on acquisition of the infection status. In particular, 3, 4, 5 or more different identification indicators can be provided for respective corresponding infection statuses. Furthermore, a visual design offers, inter alia, the advantage that an inadvertent identification of the wrong identification indicator is prevented. [0029] Particularly preferred therein is an embodiment wherein an infection status of the mobile patient support device, once recorded, is called up regardless of which identification indicator applied to the mobile patient support device is identified at a later time point. [0030] The identification of one of the identification indicators of the mobile patient support device should, for example, always call up the recorded infection status of the mobile patient support device at a treatment station as information for the responsible treatment personnel. This has the advantage, inter alia, that no doubt arises regarding the infection status, and this is not influenced by a further identification of one of the identification indicators of the mobile patient support device and furthermore, time is saved on acceptance at a treatment station, since the right identification indicator of the mobile patient support device matching the acquired infection status does not have to be searched for. [0031] Also preferred is an embodiment wherein an infection status of the mobile patient support device, once recorded, can be amended from “normal unclean” to “infection”, but not vice versa, specifically independently of which identification indicator applied to the mobile patient support device is identified at a later time point. [0032] In the event that a mobile patient support device is to be identified subsequently at a treatment station as an infected patient support device, the responsible physician, the responsible nurse and/or the responsible treatment personnel can manually correct the infection status in the system, for example, from “normal unclean” to “infected”. [0033] For the treatment, a relocation of the mobile patient support device into a treatment station is often provided. The relocation is often carried out by a person responsible for the collection and/or treatment of the mobile patient support device, for example, cleaning personnel or personnel of the internal collection and delivery service of the establishment, who can also have a personal identification indicator. Thus, the personal identification indicator can be identified in order to confirm and register the collection and/or treatment by the respective person. This has the advantage, inter alia, that for example, the responsible person can be asked regarding the momentary status of the treatment or storage and/or in case of any problems or doubts regarding the mobile patient support device after completed treatment, the person responsible for the treatment can be identified and asked. It can thereby also easily be determined subsequently which persons have had contact with the patient support device in question. This can be particularly important if it becomes clear subsequently that the infection level of the patient support device has been set too low since, for example, multiresistant microbes have been identified in the environs of the patient support device. [0034] The identification of the identification indicator can take place by means of radio and/or optically. In a preferred embodiment, the identification indicator is identified with a data reader such as, for example, a mobile scanning device. In a particularly preferred embodiment, the identification indicator is a bar code and the data reader is accordingly a bar code reader. Radio systems, for example RFID, can also be used. In a further preferred embodiment, the data reader is a mobile hand-holdable wireless and/or battery/accumulator powered device which can acquire data by means of radio or a fixed connection or other transmission techniques, transfer it to the computer system and/or call it up therefrom when the identification indicator is identified. Thus, for example, the data reader can also be a mobile telephone, smartphone or PDA. [0035] The use of a mobile, hand-holdable wireless and/or battery powered data reader has, inter alia, the advantage that such a data reader is usable, for example on a hospital ward for a plurality of rooms and can be used by different persons as required. Through the disappearance of manual, fault-prone input and instead the use of an automatic transfer and/or output of a notification, errors are largely prevented and the hygienic safety and industrial safety is ensured. The automatic transfer of data between the data reader and the central computer system or the database can take place both immediately and temporally delayed. [0036] Further, due to the identification of an identification indicator applied to the mobile patient support device, a verifiable registration can take place which can also comprise the registration of substeps of the treatment process which is particularly advantageous for both the administration from an organisational viewpoint and also with regard to legally prescribed hygiene measures. It is also, inter alia, advantageous that a data set with a notification of the infection status can be generated which, possibly in a graphical, optical, acoustic or other form, can give specific instructions in order further to ensure safety. [0037] In a further preferred embodiment, the location of the mobile patient support device can also be recorded in the database, for example, the room, the position of the bed in the room, the ward or the collection point where the mobile patient support device is situated. Particularly preferably, the recording of the location is undertaken by identification with the data reader of an identification indicator applied at the site or close to the site. This can be, for example, a bar code mounted in a room which identifies the room in which the mobile patient support device stands or the location in the room. Scanning of such a barcode before or after the identification of the mobile patient support device thus records the location of the mobile patient support device in a database of a computer system in order, for example, to enable the localisation of the mobile patient support device. The location is thus not necessarily a resting location for the patient, but can also be, for example, a medical procedure room, a treatment room, cleaning room, storage room, labour ward or a “traffic area”, for example, parking positions in corridors. Thus, not only the infection status, but also the location of the mobile patient support device can be tracked. [0038] In a preferred embodiment, the notification regarding the infection status of the mobile patient support device which is output following the identification of the mobile patient support device at the treatment station can comprise an acoustic, visual, audiovisual and/or mechanical signal. A visual signal can be, for example, a graphical representation on the data reader. Alternatively or additionally, the identification brings about the generation of a data set on the data reader. [0039] Particularly preferably, the notification is the output of a light and/or a sound by means of a suitable device. For example, a light combination can be used in which, for example, a green light or the absence of a light indicates no infection risk and a red light indicates an infection risk. The frequency at which the light is switched on and off can indicate, for example, the infection level. Furthermore, the sound can take the form, for example, of a buzzing in order to indicate an infection risk. [0040] A mechanical signal could take place, for example, by means of a vibration of the data reader, although it can also take the form of a movement and/or raising of an object. The mechanical signal can also result in a release of a restriction, locking or other blocking. This can be, for example an automatic opening of a lock on a room door, cabinet door, a cabinet and/or a cabinet compartment or a drawer. By this means, access can be granted for the cleaning personnel to suitable cleaning and/or protective means. If, for example, by means of such a mechanical notification, a personal protective equipment is made available, the cleaning personnel recognises that it is necessary, due to the infection status of the patient support device, to use this protective equipment. Similarly, for example, it can be ensured by making particular cleaning and/or disinfection materials available that means are used which are suitable and/or prescribed for the infection status of the patient support device. [0041] Furthermore, the mechanical signal can also restrict the mobility of the mobile patient support device, for example, by the activation of a braking system for the mobile patient support device or the regulation of a barrier, sliding doors and/or gate in order to prevent access to another step of the treatment. [0042] Particularly preferably, the notification comprises a plurality of components which can be, respectively, an acoustic, visual, audiovisual and/or mechanical signal. Such a multi-part notification can also accompany the treatment personnel through individual steps in the treatment process and thereby ensure the correct execution of the treatment process. [0043] The output of a notification concerning the infection status always takes place automatically, i.e. without human interaction. The device which outputs the notification is connected for this purpose, for example, via cable or radio to the computer system and in this way receives information that a notification or which notification is to be output. The notification device itself can comprise a computer or it can be controlled from the central computer system. [0044] Particularly in the cases when the notification is mechanical in nature, no human interaction is needed, so that possible error sources are eliminated. If the notification comprises, for example, the opening of a cabinet door or drawer, the opening of the cabinet door or drawer can be carried out by means of a motor that is controlled by the central computer system or by a separate notification device. If the notification comprises, for example, the release of a cabinet door or drawer, so that only this can subsequently be opened by the personnel, whilst other cabinet doors or drawers remain closed, the release of the cabinet door, the drawer and/or the cabinet can be carried out by means of a lock which is activated by a motor or an electromagnet and which is controlled by the central computer system or by a separate notification device. The release can also take place by means of an unlocking of a pre-tensioned spring in that, for example, a weight results in a movement of this locking mechanism and the pre-tensioned spring results, by its extension, for example, in the opening of a cabinet. [0045] The release or restriction can further also take place pneumatically or hydraulically and can additionally be initiated, influenced or prevented by an optical device (such as a photoelectric barrier). Thus, for example, the displacement of a weight, for example, by the placement of an object or a person at a pre-determined place can be perceived by a movement sensor, which causes a hydraulic device to release a locking and/or blocking, for example, by means of a collapsing of a telescopic rod. The displacement can also result in a lowering or raising of a pedestal or platform or a floor plate which can be perceived by a corresponding change of an optical reference signal by means of a sensor and releases a locking. Furthermore, a weight sensor can also initiate this. [0046] A restriction of the mobility of the mobile patient support device can also take place, for example, by means of a barrier in the room or a braking system in the room and/or on the patient support device. For example, a hydraulic or pneumatic device, for example, the pushing apart of a telescopic rod and/or the movement up or down of a barrier, for example, out of the floor or out of the ceiling, can restrict the mobility of the mobile patient support device. By this means, it can be ensured, for example, that a patient support device remains at a particular place until all or pre-determined treatment steps have been carried out. [0047] An indication regarding the infection status of the mobile patient support device has, inter alia, the advantage that a defined treatment process is instigated and this requires no substantial consideration by the personnel. Furthermore, a restriction or release as described above can prevent an inadvertent skipping of treatment steps and a treatment is enforced that is prescribed and is often legally required in its type and duration, e.g. the time of exposure to the disinfectant before the release of the mobile patient support device. [0048] In a preferred embodiment, the output of the notification regarding the infection status can also comprise the provision of at least one safety measure. Also to be considered herein is the preparation of personal protective equipment such as gloves, protective goggles, hood, mouth protection, overshoes, tunic, safety suit and/or visor. It is thus directly apparent to the personnel that the mobile patient support device has a particular infection status and which protective apparatus is required for the treatment. The provision of the protective equipment depending upon the infection status can take place as described above by opening or unlocking a cabinet, cabinet compartment, a drawer or another storage device. [0049] Furthermore, the provision of, for example, special cleaning, disinfection or protective materials which enable the elimination of potential pathogens or offer protection during relocation or during the treatment process of the mobile patient support device, is to be considered in order to prevent the spread of potential pathogens. The provision of cleaning, disinfection, covering, isolation or sterilisation materials or protective foils should herein be considered in order to enable the isolation of such potential pathogens. The provision of these materials can take place as described for the provision of protective equipment. [0050] The instigation of a safety measure has the advantage, inter alia, that mandatory steps are also instigated by it, in order to allow safety and hygiene without extensive consideration by the personnel, which ultimately leads to the prevention of an error-prone treatment of the mobile patient support device [0051] The provision of a safety measure can also take place automatically and/or following identification of a further identification indicator. This can result, for example, in the opening of a particular part of a cabinet only after scanning of a barcode applied to a cabinet, in order to provide the necessary safety measure. In the event of a preferred automatic provision, a scanning of such a barcode applied to the cabinet part can also bring about a registration in the database of a computer system. In addition, the respectively provided materials can also have an identification indicator which can be identified with the data reader, which also brings about the registration of the respective use of the material. Further particularly preferred is a restriction of the mobility of the mobile patient support device until, for example, the necessary safety measures have been prepared or carried out and/or registered as such in the database. Only thereafter can a release of the mobile patient support device take place. [0052] In a further preferred embodiment, the method can have successive steps in the treatment process wherein the execution of the steps is registered with a data reader. The registration of the steps can be recorded, in each case, in the database and thus documented. [0053] Such an inventive monitoring of the treatment steps offers, inter alia, the advantage that the person responsible for the treatment can always receive a notification regarding the infection status of the patient support device and/or on the step to be performed in the context of the treatment process. Thus, firstly, the safety of this person is ensured since he can protect himself according to the infection status, for example, by putting on protective clothing (PPE) and, secondly, the observance of the legally prescribed treatment is ensured in that the system guides the personnel through the individual steps of the treatment with the aid of a database. [0054] In a particularly preferred embodiment, the treatment process has specifications which can comprise the following steps, for example, for mobile patient support devices such as beds: a. The treatment typically takes place in the central bed store, which has a strict separation between “clean” and “unclean” regions, which are also clearly visually identified. b. The unclean bed arrives in the central bed store covered with a protective plastic foil. c. Initially, the unclean bedding is taken off and collected separately. Bedding from infected beds is separately packaged/sealed in plastic sacks and identified accordingly as infected laundry. d. The unclean bed equipped with a mattress, emergency evacuation sheet (between mattress and bed) and with overbed lifting pole awaits treatment in the unclean room. e. The treatment personnel put on the prescribed personal protective equipment. Depending on the level of contamination and infection, this includes gloves, mouth protection, head covering, protective goggles, hood, apron, protective suit/overalls, shoe covers. The relevant personal protective equipment is specified as mandatory. f. The treatment personnel ensure that the disinfectant to be used is available (either ready mixed in the case of a standard disinfection, or in the case of an infected bed, according to the present infection, a solution to be freshly prepared). Typically, solutions to be used for the infected bed disinfection have an expiry date, i.e. the recording of the time and date of preparation is mandatory, so that an ineffective, that is, already expired disinfectant solution is not inadvertently used at a later time point. g. For the treatment, mattress, evacuation sheet and lifting pole are separated from the bed, initially cleaned (if severely soiled) and then separately treated by wiping disinfection with a prescribed disinfectant (from RKI or VAH lists). h. The bed itself is initially cleaned (if severely soiled) and then separately treated by wiping disinfection with a prescribed disinfectant (from RKI or VAH lists). During wiping disinfection, care should be taken to ensure that tissues/cloths used are each only to be dipped in the disinfectant solution once before contact with the bed. It is mandatory to use a new cloth each time. i. If a washing tunnel is available, then the objects defined under (g) and (h) are treated by machine. The machine treatment is not used for infected beds since an exchange of the disinfectant and subsequent cleaning of the equipment would be too time-consuming and thus too expensive. Furthermore, in the case of an infected bed, the substantially more thorough wiping disinfection by hand is preferable. j. Once all the surfaces of the bed, the mattress, the evacuation sheet, the lifting pole have been treated with the relevant disinfectant, complete drying of the disinfectant must next be awaited before a “reassembly”/a “re-equipping” and a reuse can take place at all (MPG-BetreibVO—German regulations on the use of medical products). The drying typically takes place in the “clean” area. The minimum duration of the exposure time is legally defined for each disinfectant and each pathogen/the respective infection and absolutely must be complied with so that the individual parts are completely dried before the reassembly and the permissible re-use. Only a completely dried medical product, and thus a mobile patient support device, may be brought back into use. k. The bed is now situated in the “clean” area. It should be noted (and documented) here that either separate personnel are deployed who have had no contact with the “unclean” area or the treating personnel removes the (now contaminated) personal protective equipment and undertakes a hand disinfection before touching the treated objects. This is absolutely necessary since the gloves worn during the treatment are either contaminated or, due to the wearing of the gloves and the moist environment arising therein, the just treated bed is subject to a contamination risk. l. Thereafter, the reassembly of the objects and subsequently the equipping of the bed with “clean” bedding takes place. m. Subsequently, the bed is covered with a plastics protective foil for protection against renewed contamination on the transport route and the parking positions provided therefor before the next patient may use the bed. [0068] In order to enable the registration of the individual steps, additional identification indicators can be applied to the mobile patient support device or the environs of the bed treatment area. [0069] The monitoring and control of the above described treatment process can however also comprise only selected individual steps and/or other treatment steps not described above. [0070] Preferably, each step of a treatment process is listed on a chart or a display on a wall and apart from a description, is also denoted with an identification indicator, for example barcodes, which can be identified by means of a data reader and correspondingly registered in the database of the computer system. [0071] Furthermore, the person involved in the treatment process can also be registered. This person, for example, a person of the cleaning or bed personnel has a personal identification indicator. For example, the personal identification indicator can also be a barcode and the person can identify the barcode with a data reader either before or after the respective step. The registration of the steps carried out thus additionally provides proof of who was responsible for the respective treatment steps and has carried them out at which time point. In order to restrict the number of necessary actions for the identification, a combination between identification indicator and the data reader can also be radio-based, for example RFID. [0072] The registration and monitoring of all these steps accordingly leads to increased safety and a great reduction in the risk of incomplete, faulty, non-regulation or non-executed treatment. Thus not only are infection risks to personnel and patients controlled, but these steps also lead to a mandatory sequence which conforms to the law and can be proved through the registration. With this proof possibility, damage is reduced and liability risks are reduced, which can have a favourable influence on the insurance premiums of, for example, the respective hospitals. [0073] In a preferred embodiment, it can also be provided that an infection status can only be amended at the end of a successfully completed and registered/documented treatment process into a status which has no further infection risks. This leads to a further increase in the safety of the treatment process. Herein, for example, following completion and registration of all the steps provided for an infection level, the status of the mobile patient support device is automatically amended to a status which enables the release and/or re-use of this mobile patient support device. Particularly preferably herein the momentary status of the treatment process on calling up the status of the mobile patient support device is displayed until the treatment process is completed. [0074] In a further preferred embodiment, the passage of time of the steps of the treatment process is monitored and a notification is output at least at a predetermined time during at least one of the steps of the treatment process. As described above, the notification can comprise an acoustic, visual, audiovisual and/or mechanical signal. Thus, the notification can be, for example, a light which is switched on for a pre-determined time or has a colour until the pre-determined time and after the pre-determined time has another colour which remains switched on until the next step is registered. The pre-determined time data are stored in the computer system. [0075] An embodiment with a monitoring of the passage of time has the advantage, inter alia, that times of exposure to cleaning and disinfectant materials are adhered to and a complete treatment with complete elimination of the potential pathogens is ensured. The output of a notification during the time provided leads to an improvement of the treatment standard in that the personnel proceeds following a notification which automatically compares the time provided with the passage of time and thus the personnel is enabled to carry out immediate self-monitoring. [0076] Particularly preferred therein is an embodiment in which following the registration of a step of the treatment process, a timer is started, wherein during a registration of a further step of the treatment process before the expiry of the timer, a warning system is caused to output a warning notification. This leads to a monitoring of the treatment process and enables the immediate correction of an erroneous step in the treatment process. This could be, for example, a warning light or an alarm which is switched on if the pre-determined time of the step which is monitored by the timer, determined for example by the time of exposure of a disinfectant, has not yet expired and a following step has already been registered. The temporal limitation of the respective steps therefore supports the monitoring of the treatment, wherein the times stored are target times. [0077] In a further preferred embodiment, the registration of the steps of the treatment process in a sequence which deviates from a pre-determined sequence can prompt a warning system to output a warning notification. The steps of a treatment process described above provide, for example, that the equipping of a mobile patient support device with clean bedding takes place after wiping disinfection with a prescribed disinfectant. Such an embodiment offers inter alia the advantage that if the equipping unintentionally takes place before this wiping disinfection, a warning notification in the form, for example, of an alarm is accordingly output in order to prevent this and to be able to prevent a faulty action specifically in that the mobile patient support device can be handed over for treatment again, as can the associated bedding. [0078] In a further preferred embodiment, a warning notification can also comprise a restriction or release of the provision of a safety measure or a restriction of the mobility of the mobile patient support device. If, for example, a second registration takes place before the pre-determined time of a treatment step or a registration of the steps deviates from a pre-determined sequence, it can be provided that, for example, a braking system, a barrier, a sliding door and/or a gate inhibits the relocation of the mobile patient support device in order to prevent access to another step of the treatment. For example, this can also result in a restriction, locking or other blocking. This can hinder, for example an opening of a lock on a cabinet door, a cabinet and/or a cabinet compartment or a drawer in order, for example, to prevent the provision of new equipment. Naturally, this can also initiate the provision of additional safety measures by an automatic release of, for example, disinfectants and/or personal protective equipment. [0079] The registration of all treatment steps and, if relevant, also the registration of the materials used and the registration of a person and/or the location takes place automatically in all cases. For example, following the recording of the infection status in a database of a computer system, it is provided by means of a logic stored in the computer system that for each step, the identification of a corresponding identification indicator leads to an updating of the database and the step is thus registered therein. The logic can also provide that an identification of a personal identification indicator, a means used and/or a location is assigned to this step and is thus automatically registered. If, for example, the identification of a personal identification indicator for a first step is forgotten and a second step is already registered, the logic can also provide that an identification of the personal identification indicator following the second step also leads to a registration of the person for the first step and automatically updates the database for the first step. [0080] If, for example, an identification of an identification indicator for a means to be used for the first step does not take place before the registration of the second step, the same logic can provide that a warning notification is output and/or the first step must necessarily take place again. [0081] The present invention also includes that the control and/or monitoring of the treatment process can take place independently of the recording of the infection status and/or independently of the identification of the patient support device in that, for example, a desired and necessary treatment process is selected for a patient support device, for example, at the treatment station. For example, the treatment personnel, if for example, the infection status of the mobile patient support device is not known or an infection status entered in the system is not present or callable, can select a treatment process for an infected mobile patient support device. Following input of an identification indicator of the mobile patient support device, the treatment process is started automatically and the treatment personnel is guided through the selected treatment process by means of the above described notifications. It is also possible to select a treatment process which is subsequently monitored/controlled when the patient support device is provided with a notification regarding the infection level, for example, with a note as is still often the case currently. The monitoring and safety of the treatment process is thus ensured in these cases also. [0082] The monitoring of the treatment by registration of the individual steps of the treatment and the initiation of notifications regarding the infection status of a mobile patient support device offer an additional protection for both the patients and the personnel in the healthcare system. Potential spread of a pathogen is greatly minimised by the mandatory monitoring of the execution of the treatment steps. The infection status of a mobile patient support device can also be determined before the patient leaves it, for example, when the status of the patient forms a hygiene or infection risk. In such a case, the recording of the infection status in the database can take place manually on a ward or by identifying the identification indicator. An automatic notification for collection and/or treatment accordingly does not take place in the same step, but can be initiated, for example, by means of a second identification, specifically after the patient has finally left the bed. [0083] The monitoring preferably takes place by means of the identification of identification indicators with a mobile data reader. A continuous updating of the database in a computer system further enables an increase in the efficiency in that the recording of the infection status can initiate the output of a notification in the form of a communication to collect and treat the mobile patient support device. A registration of the location also enables the direct localisation of the mobile patient support device in order to shorten further the time needed for the transport and the treatment. On identification of the mobile patient support device by means of a mobile data reader at a treatment station, a notification is thereby output concerning the infection status. Thus, mandatory steps of the treatment process are followed and a correct treatment is also provided by the provision of safety measures and/or warning notifications. [0084] The registration of all steps enables not only the monitoring of the treatment, but also enables the optimisation of these processes in that a system analysis can illustrate the scope of the erroneous steps and can analyze, where possible errors are made, for example, process steps are omitted, if defined target times are overshot or undershot, how many unclean mobile patient support devices are situated where in the medical establishment, on which wards the greatest infection risks occur and what steps should take place quicker or be optimised. [0085] The method for monitoring the treatment can simply be implemented in existing systems and is also adaptable to existing or future systems. Thus, the infection status of the mobile patient support device can be linked, for example, directly to a patient status. If it is known about a patient that he is infected or has potentially been infected and thus poses an infection risk to other persons, then such an infection status of the patient can be stored in a database of a computer system. Such an infection status of the patient has the result that a mobile patient support device used for this patient also constitutes a potential infection risk. The infection status of this mobile patient support device is thus automatically linked to the infection status of the patient. [0086] Furthermore, it can be provided in the method that, for example, following the entry of a discharge of a patient in a database of the computer system, apart from the infection status of the mobile patient support device, a communication for collection and/or treatment of the mobile patient support device is automatically initiated. [0087] An identification of the identification indicator of the mobile patient support device by a person responsible for the collection and/or treatment of the mobile patient support device can also, as described above, initiate a notification concerning the infection status of the mobile patient support device by means of a provided linkage of the mobile patient support device to the infection status of the patient. [0088] This has the advantage, inter alia, that both the recording of the infection status of the mobile patient support device and also the initiation of a communication for collection and/or treatment of the mobile patient support device takes place automatically after the discharging of the patient. This reduces the number of necessary actions for the monitoring of the treatment. [0089] Furthermore, in the method, the registration of the respective persons, mobile patient support devices, locations, wards and actions can be combined in a database. [0090] Thus, not only can a room allocation take place dependent upon the infection status and the number of mobile patient support devices, but threshold values, for example, for the number of existing and/or collected unclean mobile patient support devices and/or the number of the personnel available for the start of the treatment can also be provided, in order further to increase the efficiency of the treatment. The automatic room allocation can also provide that mobile patient support devices are only stored at the location provided. If a mobile patient support device is placed at an incorrect location, following suitable registration, the method can further output a warning notification. [0091] A system which monitors, for example, the usage or issuing of materials, for example with a sensor and detector, can be implemented in the method with comparable identification indicators as described above. Thus, for example, a dispenser for fluids, for example, disinfectant or cleaning fluid, or for example, cleaning cloths or laundry can comprise a movement sensor and/or a weight sensor which can check the usage and, can further also have an identification indicator, for example, a barcode. An identification of such a barcode before the actuation of a dispenser has the result that following the actuation of the dispenser, a sensor confirms the usage and a further registration of the usage takes place in the database of a computer system. This has the advantage, inter alia, that, for example, the use of disinfection materials that are provided and mandatorily prescribed can be proved. [0092] The above described identification of identification indicators and/or registration of such identifications and/or other automatically registered steps of the treatment process can be stored automatically in the database of the computer system (preferably unalterably in order to increase the reliability of the proof). [0093] The invention further relates to systems for monitoring the treatment of mobile patient support devices which serve for carrying out the above described method. Such a system has at least one computer system with a database, at least one data reader, at least one identification indicator at each mobile patient support device to be monitored, and at least one device to output a notification. The functioning of this system and other embodiments are disclosed in the above description for the method. [0094] In particular, the system in preferred embodiments can additionally comprise at least one further identification indicator at each bed to be monitored which are assigned different infection statuses, at least one further identification indicator in order to record the location of the mobile patient support device, at least one identification indicator on each person involved in the treatment process, identification indicators for the different steps of the treatment process and/or a warning system. [0095] The computer system can be, for example, a single computer with a database which is connected to all the other components, for example, the data reader, notification devices, etc. The computer system can also comprise a server with a database in a common network with a plurality of further computers which themselves are each connected to one or more further components. Thus, for example, a computer can be provided both at each (patient treating) ward as well as at the treatment station, said computer being connected to the server via the network. In this way, the data can be recorded at the individual wards and subsequently transferred from the computers there to the server and stored in the database. BRIEF DESCRIPTION OF THE DRAWINGS [0096] The invention will now be described in greater detail making reference to the drawings. In the drawings: [0097] FIG. 1 shows a schematic representation of the processes in the treatment monitoring in a preferred embodiment; [0098] FIG. 2 shows a schematic representation of the processes in the treatment monitoring in a further preferred embodiment; and [0099] FIG. 3 shows a schematic representation of a part of the monitoring of the treatment processes. DETAILED DESCRIPTION [0100] FIG. 1 shows a schematic representation of the monitoring of a mobile patient support device (e.g. a bed) according to a preferred embodiment. The monitoring takes place, for example, according to the following steps. In a first step, based upon an infection status or infection risk of a patient, the infection status of the mobile patient support device ( 1 ) is recorded. This takes place, for example, manually in a ward and is entered into a database of a computer system ( 2 ). In a next step, the mobile patient support device is collected and relocated into a treatment station ( 4 ). Here, in a next step, an identification indicator ( 10 ) of the mobile patient support device ( 1 ) is identified with a data reader ( 3 ) which is connected to the computer system ( 2 ). The identification of the identification indicator ( 10 ) calls up the infection status of the mobile patient support device ( 1 ) from the database of the computer system ( 2 ). Then the output of a notification concerning a device ( 5 ) regarding the infection status is initiated at the treatment station ( 4 ), for example, by means of a warning lamp. This increases, inter alia, the safety of the treatment personnel and ensures a prescribed treatment process. [0101] FIG. 2 shows a schematic representation of the monitoring of a mobile patient support device (e.g. a bed) according to a further preferred embodiment. The monitoring takes place, for example, according to the following steps. In a first step, based upon an infection status or infection risk of a patient, the infection status of the mobile patient support device ( 1 ) is recorded. This takes place through an identification of a first identification indicator ( 10 ) or a second identification indicator ( 11 ) of a mobile patient support device ( 1 ) by means of a data reader ( 3 ) depending on the infection status or infection risk of the patient. Herein, one of the two identification indicators ( 10 , 11 ) represents a potential infection risk and the other identification indicator represents an unclean but not infected status. The identification indicators ( 10 , 11 ) are also configured so that by means of an unambiguous visual recognition of the infection status represented on the identification indicator, they support the acquisition of the infection status. The data reader ( 3 ) is in communication with a database in a computer system ( 2 ) and, by means of the identification, registers the infection status of the mobile patient support device ( 1 ) in the database. In addition, for example, information regarding the location where the patient support device is situated and the person who has acquired the infection status are registered by means of the identification of further identification indicators ( 12 , 13 ) by means of the data reader ( 3 ). [0102] If the acquisition of the infection status has not been undertaken or not correctly, it can further be provided that a manual input or correction in the database of the computer system ( 2 ) can only be undertaken by an authorised person. [0103] In a next step, the mobile patient support device ( 1 ) is collected by, for example, collection and/or treatment personnel who, by the identification of the identification indicator ( 10 , 11 ) and/or a further identification indicator ( 12 , 13 ) can also register/document the process step of the collection with a further data reader ( 38 ). An identification of one of the two identification indicators ( 10 , 11 ) of the mobile patient support device ( 1 ) calls up the infection status of the mobile patient support device ( 1 ) (regardless of which of the two identification indicators have been identified) and enables a correct processing by the personnel in order to relocate the mobile patient support device ( 1 ) safely into the treatment station ( 4 ) and to contain the risk of the potential spread of pathogens. The personnel can further be recorded and registered in the database of the computer system ( 2 ) through the identification of a further personal identification indicator ( 14 ) by means of the data reader ( 3 ). [0104] In a next step, one of the identification indicators ( 10 , 11 ) is identified at the treatment station ( 4 ) by means of the data reader ( 3 A) provided there. The infection status of the mobile patient support device ( 1 ) is called up (regardless of which of the two identification indicators has been identified) and initiates the output of a notification regarding the infection status by means of a device ( 5 ), for example, through a warning lamp. In the event of an infection risk, the notification comprises the output of a safety measure. The safety measure can be, for example, the provision of personal protection equipment and/or the release of means necessary for the treatment by means of the automatic opening of, for example, a further device ( 6 ), for example, in the form of a cabinet door. The treatment personnel can put on the personal protection equipment provided and carry out the treatment process only with the released cleaning and disinfecting materials. [0105] In order to ensure a correct and safe progress of the treatment, the individual treatment steps can be registered by identifying identification indicators by means of a data reader and, furthermore, the time elapsed between the registrations can further be compared with a provided target time. If the registrations do not take place in the correct sequence and/or not according to the provided target time, a warning device can automatically output a warning notification. This can be, for example, apart from a warming lamp ( 8 ), also a mechanical restriction of a provision via a further warning device ( 9 ), for example, the locking of a cabinet door in order to prevent the subsequent steps, or a restriction of the mobility of the mobile patient support device ( 1 ), for example, through the effect of a locking, braking or barrier system. [0106] By means of the registration of these treatment steps, it can also be provided that only after a completed treatment process in which all the steps have been registered according to the stored and provided sequence and target times, the infection status of the mobile patient support device ( 1 ) is adjusted and a new status of the mobile patient support device ( 1 ) can be recorded as “treated” or “available”. [0107] FIG. 3 shows a schematic representation of a preferred embodiment of the monitoring of the treatment processes. Herein, for example, different steps (A-F) of the treatment process listed on a wall chart ( 7 ) are provided alongside a process description (I-VI), also with the identification indicators ( 71 - 76 ). The different treatment processes can be registered in the database of a computer system ( 2 ) by means of a data reader ( 3 ) in that the corresponding identification indicators ( 71 - 76 ) can be identified at the treatment station ( 4 ) with the data reader ( 3 ). The data reader ( 3 ) is also in communication with a computer system having a database. The registrations can further, according to FIG. 2 , cause one or more warning devices ( 8 , 9 ) to output a warning notification, in order to correct possible erroneous steps and to ensure the safety of the treatment. REFERENCE SIGNS [0108] 1 Mobile patient support device [0109] 10 Indicator of the mobile patient support device [0110] 11 Further indicator of the mobile patient support device [0111] 12 Indicator of location [0112] 13 Personal indicator [0113] 14 Further personal indicator or personnel treatment [0114] 2 Computer system with a database [0115] 3 Data reader [0116] 3 A Further data reader [0117] 3 B Further data reader for collection and delivery service [0118] 4 Treatment station [0119] 5 Device for output of a notification [0120] 6 Further device for output of a notification [0121] 7 Wall chart [0122] 71 Identification indicator process step A [0123] 72 Identification indicator process step B [0124] 73 Identification indicator process step C [0125] 74 Identification indicator process step D [0126] 75 Identification indicator process step E [0127] 76 Identification indicator process step F [0128] 8 Warning light [0129] 9 Warning device

The invention concerns a method for monitoring the treatment of mobile patient support devices. The infection status of a mobile patient support device is registered in a database in a computer system. The mobile patient support device is identified at a treatment station using a data reader which identifies an identification tag attached to the mobile patient support device. Information on the infection status of the mobile patient support device is output at the treatment station.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation of PCT application No. PCT/AU01/01058, filed Aug. 24, 2001, and published under PCT Article 21(2) in the English language on Feb. 28, 2002, as WO 02/16062 A1. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an improved metal flow system or runner/gate arrangement, for use in the production of pressure castings made from aluminium alloys, such as but not exclusively in a molten or thixotropic state, suitable for use with various forms of pressure casting machines including, but not limited to, existing hot and cold chamber die casting machines. 2. Description of Related Art An understanding has developed throughout the international pressure casting industry that it is necessary to use large runners to prevent premature freezing of the molten aluminium alloy metal during pressure casting. Within the industry, there are many different design methods which are thought to provide satisfactory castings from aluminium alloys. However, common to these different methods is a reliance on runner systems of large volume relative to casting size and low metal flow velocities through the runners. To illustrate the large volume runner systems used by current systems in pressure casting of aluminium alloys, it is usual for a foundry having an annual casting production level of 250,000 tonnes of saleable castings to have processed some 450,000 tonnes of alloy, where the weight of sprue/runner metal of alloy is about 200,000 tonnes. In this production, it is usual to use oversized runners, in order to prevent alloy freeze-up, with the result that runner velocities of about 10 m.sec −1 are achieved. Corresponding gate velocities are about 30-45 m.sec −1 , with the gate velocity more usually being in the range of 30-35 m.sec −1 . Of the aggregate quantity of melt poured, only about 55% results in productive output. As a consequence, there is a need for an excessive inventory of aluminium alloy required to allow for the remaining metal consumed as runner metal to be recycled. There accordingly is a high level of excess energy consumption in heating alloy which, after casting, needs to be recovered and recycled. Also, it is typical for there to be alloy loss at a level of about 3% of the total tonnage poured which, on the indicated level of foundry output, represents a loss of about 13,500 tonnes (at a cost of about AU$30M). In such production, there are significant costs additional to the high level of aluminium alloy inventory, the loss of alloy and the cost of heating, recovery and recycling runner/gate alloy. At the level of output indicated, there may be five furnaces required for preparation of molten alloy for casting. Such furnaces can cost about AU$15M each, and reducing the number of these furnaces by only one, along with its ancillary equipment, would achieve a substantial saving in capital expenditure. Also, casting die costs can amount to about 15% of overall production cost, and an improvement in die life would provide substantial scope for further savings. Indeed, the overall cost burden is such that it serves to highlight how entrenched is the thinking on established foundry practice on pressure casting of aluminium alloys. We have found that, by use of the present invention, it is possible and practical to produce high quality pressure castings of aluminium alloys of at least comparable quality to those provided by established foundry practice, but with substantial cost savings. The nature of the cost savings are detailed later herein. SUMMARY OF THE INVENTION The present invention provides or uses, for the pressure casting of aluminium alloy in a pressure casting machine having a mould or die which defines a die cavity, a metal flow system through which aluminium alloy is able to flow along a metal flow path into the die cavity. The metal flow system according to the present invention has an arrangement which defines at least part of the flow path and which includes at least one runner and what is referred to herein as a controlled expansion port or point (CEP). Thus, according to the invention, there is provided a metal flow system, for use in casting aluminium alloy using a pressure casting machine, wherein the metal flow system is provided by a component of a die or mould assembly for the machine, the die or mould assembly defines a die cavity and the component defines at least part of an alloy flow path for the flow of aluminium alloy from a pressurised source of substantially molten aluminium alloy of the machine to the die cavity, the flow path includes at least one runner and a controlled expansion port (herein referred to as a “CEP”) which has an inlet through which the CEP is able to receive aluminium alloy from the runner and an outlet through which aluminium alloy is able to flow from the CEP for filling the die cavity, and wherein the CEP increases in cross-sectional area from the inlet to the outlet thereof to cause substantially molten alloy received into the runner to undergo a substantial reduction in flow velocity in its flow through the CEP whereby the aluminium alloy flowing through the CEP attains a viscous or semi-viscous state which is retained in filling the die cavity. The invention also provides a pressure casting machine, for use in casting aluminium alloy using a pressure casting machine, wherein the machine includes a metal flow system provided by a component of a die or mould assembly for the machine, the die or mould assembly defines a die cavity and the component defines at least part of an alloy flow path for the flow of aluminium alloy from a pressurised source of substantially molten aluminium alloy of the machine to the die cavity, the flow path includes at least one runner and a controlled expansion port (herein referred to as a “CEP”) which has an inlet through which the CEP is able to receive aluminium alloy from the runner and an outlet through which aluminium alloy is able to flow from the CEP for filling the die cavity, and wherein the CEP increases in cross-sectional area from the inlet to the outlet thereof to cause substantially molten alloy received into the runner to undergo a substantial reduction in flow velocity in its flow through the CEP whereby the aluminium alloy flowing through the CEP attains a viscous or semi-viscous state which is retained in filling the die cavity. Additionally, the invention provides a process for producing castings of an aluminium alloy, using a pressure casting machine having a pressurised source of substantially molten aluminium alloy and a die or mould assembly defining a die cavity, wherein the process includes the steps of causing the alloy to flow from the source to the die cavity along an alloy flow path defined by a component of the die or mould assembly; causing the alloy, in its flow along the flow system, to flow through a runner and through an inlet end of a controlled expansion port (herein referred to as a “CEP”); and causing the alloy, in its flow through the CEP to an outlet end of the CEP, to decrease in flow velocity, whereby the alloy is caused to attain a sufficient flow velocity at the inlet of the CEP, and to undergo a substantial reduction in that flow velocity in its flow through the CEP, such that the alloy attains a viscous or semi-viscous state and retains that state in filling the die cavity. The controlled expansion port (CEP) has an inlet end or entry from the runner and an outlet end or exit from which alloy flows to or into the die cavity. The entry into the CEP from the runner may be of the same cross-sectional area, but preferably is smaller than the runner. However, the outlet end of the CEP or exit into the cavity has a larger cross-sectional area than the CEP inlet so as to achieve a substantially lower metal velocity than that at the inlet end of or entry to the CEP. Over the length of the CEP between its entry to the CEP and its exit the cross-sectional area of the CEP increases so that the flow velocity of alloy therethrough decreases, while the CEP is preferably tapered from the inlet to its exit. The outlet end or exit of the CEP may, and preferably does, define an inlet to the die cavity. However, in an alternative arrangement, the runner of the metal flow system may terminate at or adjacent to an inlet to the die cavity. In that alternative arrangement, the metal flow system may include a portion of the die cavity at or adjacent to the runner outlet, with that die cavity portion defining at least part of the extent of a CEP from the outlet towards the inlet of the CEP. However, in a further alternative arrangement, the CEP may be intermediate the ends of respective runners. The first runner is upstream of the CEP in the alloy flow direction, and a second runner is downstream of the CEP in that direction. That is, the first runner provides alloy flow to the inlet of the CEP and the second runner provides alloy flow from the exit of the CEP to the die cavity. In that further alternative, the second runner preferably has a cross-section which is not less than that of the CEP outlet end. The metal flow system may be of a form providing for control of metal flow velocities through the runner and CEP whereby at least a substantial proportion of the aluminium alloy flowing through the die cavity is in a viscous or semi-viscous state. For this purpose, the arrangement preferably is such that the aluminium alloy metal flow velocity through the inlet end of the CEP is in excess of 40 m/s, preferably in excess of 50 m/s, such as from 80 to 110 m/s. The flow velocity at the outlet end of the CEP generally is from about 50 to about 80%, preferably from 65 to 75% of the inlet end velocity. The outlet end velocity may be in excess of 20 m/s, preferably in excess of 30 m/s, such as from 40 to 95 m/s, and most preferably from about 40 to 90 m/s. These velocities are much greater than the values of the current systems. In addition to the increased alloy flow velocity through the runner and CEP able to be provided in the system according to the invention, it will be noted that the alloy flow velocity through the inlet of the CEP exceeds that of the CEP outlet end or exit flow velocity. This is the converse to the situation obtaining with the runner and gate arrangements of the current systems, and results from a difference in the cross-sectional area relationship between the respective arrangements. Thus, while the known systems utilise a gate of lesser cross-sectional area than the corresponding runner, the present invention can have a CEP exit which is of greater cross-sectional area than the corresponding runner cross-section upstream of the CEP. In the former case, metal flow is constricted and increases in velocity through the gate relative to the runner while the converse is able to be achieved in the system of the invention. In such runner/CEP arrangement according to the invention, the CEP can be defined by a terminal portion at the die cavity end of the runner. That terminal portion can be relatively short in the direction of aluminium alloy metal flow, such as up to about 5 mm in length. However, in most instances, a CEP may be much longer, depending on the size of the casting to be made. Thus, a CEP may have a length up to at least 40 mm, but it generally is up to about 20 mm, for example 10 to 15 mm, in length. However, in an alternative arrangement, the cross-sectional area of the runner can be maintained up to the die cavity, with the required CEP being provided by the shape of a portion of the die cavity. That is, there may simply be a runner, with no gate in the conventional sense; but rather a notional CEP defined within the die cavity by the mould or die. However, as indicated above, the flow path may have a first runner from which alloy flows into the CEP, and a second runner to which alloy flows from the CEP to the die cavity. In such two-part runner arrangement, the second runner preferably has a cross-sectional area which is not less, and most preferably is larger, than the cross-sectional area of the outlet end of the CEP and, hence, does not provide a constriction to flow of alloy from the CEP to the die cavity. Where the CEP opens to, or is defined by a portion of the die cavity, the system of the invention enables the production of castings by direct injection of alloy to the die casting. However, where the CEP is between respective runners, the invention enables indirect injection. In each case, the system may have more than one flow path each having a respective runner/CEP arrangement, with each runner and its CEP providing for the supply of alloy to a common die cavity or to a respective die cavity. Particularly in the latter case, where each CEP is between respective first and second runners as discussed above, at least each second runner which provides for alloy flow beyond the outlet end of its CEP may extend laterally from a direction of alloy flow into the system. Thus, at least each second runner may be defined along a parting plane between two die tool parts which define each die cavity. According to the present invention, where an actual CEP is provided by a terminal end portion at the die cavity end of the runner, it can be a simple enlargement which tapers to increase in cross-section beyond the runner. The actual CEP preferably is of round or rectangular cross-section. A channel defining a runner providing alloy flow to the inlet of a CEP, that is, a first runner, can be linear. However, it is preferred that the channel has severe changes of direction to encourage turbulence in the flow of aluminium alloy to the CEP. Thus, the runner channel may be a dog-leg form in having at least two portions which are mutually inclined. Indeed, some of the better results obtained, in use of the system according to the invention, have utilised a runner in which an upstream runner portion extends a short distance beyond its junction with a downstream portion, to define a blind end of the upstream portion. The use of a runner giving rise to turbulence in aluminium alloy metal flow therethrough is in contrast to practice in the current systems. That is, the runners and gates of the current systems are designed to minimise turbulence therein and, hence, within the die cavity, thereby achieving flow which approximates to laminar flow or which is as smooth as possible. At least for larger aluminium alloy castings, it is current practice, to utilise a chisel, fangate or tapered tangential runner, or oppositely extending twin tapered tangential runners. Such runners need to be carefully designed in order to achieve a smooth flow of aluminium alloy metal from the shot sleeve to the gate in each runner and to ensure flow along the length of each runner. As indicated, these and other runners used in current practice are oversized in order to avoid molten metal from freezing and, as a result, they give rise to the relatively low runner and gate flow velocities. However, due to the runners being oversized and necessitating a correspondingly large piston/shot sleeve to feed molten alloy to them, the volume and hence weight of solidified biscuit (slug) and runner metal is substantial relative to the casting volume and weight. The aluminium alloy metal flow system of the present invention obviates the need for such complex and relatively large runner systems, and enables the runner metal to be small relative to the current systems. That is, the ratio of runner metal weight to aluminium alloy product weight with use of the present invention is substantially better than with use of current systems. Thus, the inventory of aluminium alloy required can be substantially reduced, as can the energy level in melting alloy which, after casting, needs to be recovered and recycled. Also, while the percentage loss of alloy during remelt/holding is about the same as with current systems (3%), the invention is able to result in the tonnage poured being substantially reduced, and the tonnage of alloy lost therefore is correspondingly reduced. Additionally, the runner, of the metal flow system of the invention, can be relatively short, further reducing the quantity of runner metal. Prior practices generally have resulted in a weight of runner/sprue metal which solidifies with a casting, and needs to be separated and recycled, which is in excess of 50% of the casting weight and over 100% in some cases. In contrast, the metal flow system of the invention enables the weight of runner/CEP metal which is less than 30% of the casting weight, in some instances down to about 15% to 20%. This, of course, is a significant practical benefit, since the cost of recovering and re-processing of recycled metal is correspondingly reduced. Also, the present invention generally obviates the need for die cavity overflows, unless these are required to facilitate ejection of a casting from the die. The higher runner/CEP metal velocities preferably used in the present invention are a major factor in achieving these savings. However these velocities do not necessitate larger and, hence, more expensive pressure casting machines than are used with current systems. Rather, the velocities are obtainable with the same casting machines as used in casting aluminium alloys with current systems, and are enabled by use of metal flow systems of substantially reduced cross-sectional areas compared to current systems. These reductions in cross-sectional area, combined with the simple form of the metal flow system of the present invention, are factors which enable the reduction in sprue/runner metal. However, there are inter-related factors which enable the reduction in runner metal to be further optimised. Inter-related factors further enabling the ratio of sprue/runner metal to aluminium alloy casting weight to be reduced are that the metal flow system of the invention enables a high level of flexibility in choice of location of an inlet to a die cavity, in contrast to the limited choice with a gate in prior art practice, and the ability with the invention to produce sound castings using what effectively is a direct injection arrangement for the supply of alloy to the die cavity. As previously indicated, the runner/CEP arrangement can be of a form that is non-linear, such as a dog-leg or even cranked form. Rather than having, for example, a runner which has a long narrow gate extending therealong, as in the tangential runners of current systems, the metal flow system of the invention can, for example, have a terminal portion which extends directly towards and communicates with the die cavity, for example, substantially perpendicularly through a wall defining the die cavity. The location at which this communication is provided can be chosen from various suitable locations, with a principal determinant being the need to avoid die erosion at an adjacent surface of the die cavity. However, where a notional CEP is to be defined within the die cavity, the form and dimensions of the die cavity at such location need to be such as to allow for this, and avoidance of the erosion can therefore be a determinate of choice of communication location. With use of the metal flow system of the present invention, temperature conditions may be similar to those used with current systems. Thus, the die may be operated at a temperature of from about 160° C. to about 220° C., while the aluminium alloy can be cast at a temperature of from about 610° C. to about 670° C., depending on the alloy concerned. Under such conditions, good aluminium alloy castings are able to be produced which are at least comparable in quality to those produced with current systems. Under such conditions, die cavity fill is achieved while the aluminium alloy is in a substantially semi-liquid state or thixotropic state. In contrast to the temperature conditions used in practice with current systems, the metal flow system of the present invention also enables production of good aluminium alloy castings under temperature conditions in which die cavity fill is with the aluminium alloy in a substantially semi-solid or thixotropic state. Under these conditions die temperatures can be in the range of from about 60° C. to about 100° C., with alloy metal temperature around 610° C., depending on the alloy concerned. As will be appreciated, these conditions enable energy costs to be reduced, while the lower aluminium alloy casting temperature can assist in maintaining alloy compositional stability and in improving die longevity. While casting is possible under temperature conditions intermediate the indicated two sets of conditions, use of conditions of one or other of those sets is highly preferred. In general, it can be difficult to maintain a consistently high casting output quality at intermediate conditions, although those conditions can be used for at least some forms of castings. The metal flow system of the present invention can be used advantageously with the full range of conventional aluminium die casting alloys. However, at least under the lower temperature casting conditions detailed above, it is found that at least reasonable to good quality castings can be produced with aluminium alloys of some series which are not regarded as suitable casting alloys using current pressure casting systems. Examples of the latter alloys which may be able to be cast, using the metal flow system of the present invention, include alloys of the 7000 series. The form of a CEP, beyond the requirement that it increases in cross-section from its inlet end to its outlet end, can vary substantially. The length of a CEP is variable, depending on the size of the casting to be made. The length can be from about 5 to about 40 mm, such as from 5 to 20 mm, and preferably about 10 to 15 mm. It may be convenient for a CEP to be of circular cross-section. However, other cross-sections such as square or rectangular can be used, depending largely upon the casting design and where the flow from the CEP enters the die cavity. A CEP may have an axis or centre line which is straight. However, a CEP can, if required, have an arcuate or bent axis or centre line, such that it provides a change in direction of alloy flow therethrough. The dimensions and form of a CEP can vary in accordance with a number of variables. These include the size of castings being made; the type, size and power of the machine being used; the particular aluminium alloy being cast; the location at which alloy flows into the die cavity, and whether or not at least a portion of the CEP is defined by a region of the die cavity; and the microstructure being sought. These variables can make it difficult to determine the suitable form for a CEP for a given casting to be made, at least if there is to be substantially complete control over that microstructure of a casting to be made. However, under appropriate conditions, it is found that a CEP can provide a casting which, for many purposes, has an optimum microstructure substantially throughout the casting. While some larger dendrites up to about 100 μm may come from the shot sleeve, in the case of a cold-chamber die casting machine, this microstructure is one characterised by fine degenerate dendrite primary particles in a matrix of secondary phase, with the primary particles less than 40 μm, such as about 10 μm or less. For this, the CEP is to be able to achieve alloy having a semi-solid state in its flow therethrough, in which the alloy possesses thixotropic properties, and also is to be able to maintain that state and those properties in the alloy substantially throughout flow of the alloy to fill the die cavity. For at least some forms of CEP able to achieve this, using a die mould providing for sufficiently rapid solidification of alloy therein, we have found that solidification of the alloy is able to progress back into the CEP such that alloy solidified in the CEP has a specific microstructure. While not necessarily definitive of all suitable forms for a CEP, attainment of that specific microstructure is one basis on which the overall requirements for a CEP can be quantified, at least where the indicated optimum casting microstructure for some applications is required or acceptable. However, this discovery is not limited to applications where that casting microstructure is required or acceptable since, as detailed herein, it is a microstructure able to be modified by heat treatment, if this is required for other applications. The specific microstructure for a CEP is one which, in axial sections through metal solidified in the CEP, exhibits striations or bands which extend transversely with respect to the direction of alloy flow through the CEP and which result from alloy element separation. A CEP able to achieve such microstructure is one capable of generating intense pressure waves in the alloy in its flow through the CEP. The bands, which may extend laterally across substantially the full width of the CEP and along substantially its full length, are found to have a wavelength of the order of 200 μm. Also, the separation of elements is found to result in substantial separation of primary and secondary phases, with the primary phase present as fine, rounded or spheroidal degenerate dendrite particles substantially less than 40 μm in size, such as about 10 μm or less. Thus, for example, with an aluminium alloy having magnesium as its principal alloy element, such as the alloy CA313 (corresponding to the Japanese alloy ADC-12, the US alloy A380 and the UK alloy LM-24), it is found that alternate striations or bands are respectively aluminium-rich and magnesium-rich, due to separation of the more dense aluminium and less dense magnesium. The aluminium-rich bands are relatively richer in primary phase, present as fine, rounded or spheroidal degenerate dendrite particles substantially less than 40 μm in size, such as about 10 μm or less. In contrast, the magnesium-rich bands are found to be richer in secondary phase intermetallic particles, such as of the form Al x Mg y Si z . Thus, according to a preferred form of the invention, there is provided a metal flow system, for use in pressure casting of an alloy, using a pressure casting machine, wherein the system includes a mould or die tool component in which a runner and a CEP define at least part of a flow path along which aluminium alloy is able to flow for injection into a die cavity defined by a mould or die; wherein the CEP, from the inlet end to the outlet end thereof, increases in cross-sectional area whereby the state of alloy in its flow through the CEP is able to be modified to achieve a semi-solid state possessing thixotropic properties and to enable the alloy in that state to flow into the die cavity; and wherein the CEP has a form such that, with solidification of alloy in the die cavity and back along the flow path into the CEP, to provide a resultant casting having a microstructure characterised by fine degenerate dendrite primary particles in a matrix of secondary phase, alloy solidified in the CEP has a microstructure in planes parallel to the flow direction characterised by striations or bands extending transversely with respect to the alloy flow therethrough, with the bands resulting from alloy element separation, and with alternate bands relatively richer in respective elements and respectively in primary and secondary phases. The invention also provides a process for producing an article by high pressure casting, wherein substantially fully molten alloy is supplied under pressure to a metal flow system for flow along a flow path defined by the system to a die cavity defined by a mould or die; the flow path is defined at least in part by a mould or die tool component; and wherein the component is formed to define, as part of the flow path, a CEP which, from an inlet end to an outlet end thereof, increases in cross-sectional area whereby the state of the alloy in its flow through the CEP is modified to achieve a semi-solid state possessing thixotropic properties and to cause the alloy to flow in that state into the die cavity; the form of the CEP being provided such that, with solidification of the alloy in the die cavity and back along the flow path into the CEP, to provide a resultant casting having a microstructure characterised by fine degenerate dendrite primary particles in a matrix of secondary phase, alloy solidified in the CEP has a microstructure characterised by striations or bands extending transversely with respect to alloy flow therethrough, with the bands resulting from alloy element separation, and with alternate bands relatively richer in respective elements and respectively in primary and secondary phases. The preferred system and process are to be such that, if solidification of alloy in the die cavity is sufficiently rapid, the respective microstructures are obtained. Such rapid solidification most preferably is achieved in use of the invention. However, in addition to the need for heat energy extraction from the mould or die to achieve this it can be necessary to control the temperature of the component defining the CEP such that alloy in the CEP is able to be solidified. Most conveniently, heat energy extraction is limited up-stream of the inlet end of the CEP, to enable a solid-liquid interface to be established at, or a short distance downstream from, the inlet end of the CEP. The pressure casting machine with which the metal flow system of the invention is used can be of a variety of different forms. It may, for example, be a hot- or cold-chamber high pressure die casting machine having a nozzle from which alloy is able to be injected into the metal flow system, for flow along the flow path of the system and through the CEP of the flow path, to the die cavity. Alternatively, the machine may be of the Thixomatic type, such as disclosed for example in U.S. Pat. No. 5,040,589 (herein patent '589 to Bradley et al), in which alloy is advanced along a barrel to an accumulation chamber at one end of the barrel, and then ejected through a nozzle at the one end of the barrel by axially advancing the screw. From the nozzle of a Thixomatic type of machine, the alloy is able to be injected into the metal flow system, again for flow along the flow path of the system, through the CEP of the flow path, to the die cavity. In a further alternative, the machine may be of the type disclosed in our Australian provisional application (attorney reference IRN642429), entitled “Apparatus for Pressure Casting” filed on Aug. 23, 2001. The disclosure of that provisional application is incorporated herein by reference, and is to be read as forming part of the disclosure of the present invention. In that disclosure of our Australian provisional application (IRN 642429), there is provided a molten alloy transfer vessel having a capacity for holding a measured volume of alloy required for transfer to a die tool and sufficient to produce a given casting, or for simultaneously producing a plurality of given castings which usually are similar. With a machine having such transfer vessel, the alloy in the transfer vessel is able to be discharged via an outlet port by pressurising an upper region of the vessel. From such discharge port, the alloy is able to be injected into the metal flow system as described above for the other machine types. It is indicated above that the present invention enables production of castings having an optimum microstructure substantially throughout. That microstructure is indicated as having fine degenerate primary particles in a matrix of secondary phase, with the primary particles less than 40 μm, such as about 10 μm or less. However, it also is indicated that some larger dendrites ranging up to about 60 to about 100 μm can be present. Those larger particles are indicated as having come from the shot sleeve, reflecting use of a cold-chamber die casting machine. With use of a hot-chamber machine, this influx of larger dendrites can be avoided, providing a casting with only fine primary particles less than about 40 μm. However, even with use of a cold-chamber machine, the volume fraction of such larger particles can be kept to a relatively low level. A conventional hot-chamber die casting machine is not suited to use in pressure casting of aluminium alloys, due to its components being attacked by the alloy. Thus, this type of machine enables practical avoidance of larger dendrite particles only in so far as new materials not attacked by aluminium alloys are used or become available. However, a machine of the type disclosed in our above-mentioned provisional application (IRN 642429) provides an alternative form of hot-chamber die casting machine and, as it is amenable to manufacture of materials not attacked by aluminium alloys, the use of its machine does enable avoidance of larger dendrite particles. Thus, use of the present invention in a machine as disclosed in that provisional application (IRN 642429) enables production of castings, by high pressure hot-chamber die casting, which are substantially free of primary dendrites in excess of 40 μm. As indicated above, it is highly desirable that the alloy has a flow velocity at the outlet end of a CEP which is close to or within a preferred range. The flow velocities indicated are high relative to flow velocities used in high pressure die casting machines and in a Thixomatic type of machine. As the alloy flow velocity decreases as the alloy passes through the CEP, due to the CEP increasing in cross-section in the flow direction, the flow velocity at the inlet end of the CEP therefore needs to be even higher. The flow velocity of the alloy through the outlet end of the CEP preferably is 20 to 50% less, such as 25 to 35% less, than the flow velocity at or upstream of the inlet end of the CEP. In many instances, the outlet flow velocity may be about two-thirds of the flow velocity at or upstream of the inlet end such that, with an outlet flow rate of about 60 m/s, the flow velocity at or upstream of the inlet to the CEP may be about 90 m/s. The machine with which the metal flow system is used needs to have an alloy output flow velocity which is consistent with these requirements or, for a given machine, the metal flow system needs to have a CEP with inlet and outlet end cross-sectional areas which are consistent with attaining the required flow rates for the CEP from the output flow velocity for the machine. Thus, for a machine providing a relatively low output flow velocity, such as due to a low piston velocity, the inlet and outlet cross-sectional areas of the CEP will need to be small, resulting in an extended flow time. With use of a metal flow system according to the present invention, having a CEP in which solidified alloy is able to exhibit a microstructure characterised by striations or bands resulting from alloy element separation, it is believed that the microstructure obtained in a resulting casting is unique. That microstructure is broadly detailed above, in terms of it having fine, degenerate dendrite primary particles in a matrix of secondary phase, with the primary particles less than 40 μm but with some larger dendrites up to about 100 μm coming from the shot sleeve if a cold-chamber machine is used. The primary particles not only are small, frequently about 10 μm or less, but they also are evenly distributed. Moreover, the microstructure is able to be obtained substantially fully throughout a casting produced by the process of the present invention. A further more important factor is one which results from the alloy element separation which occurs in the CEP under the conditions which cause the alloy to achieve a semi-solid state possessing thixotropic properties. It is found that the microstructure of the casting reflects this separation in at least the degenerate dendrite primary particles of the casting, as with the primary particles in the striated or banded microstructure of alloy solidified in the CEP, as explained in the following. With normal growth of dendrites, the core or first part to solidify is relatively rich in aluminium. As the dendrites grow, the concentration of a secondary element in the surrounding molten alloy accordingly increases, due to the removal of the aluminium, while the concentration of the aluminium in the surrounding melt decreases. Thus, the growing dendrite exhibits a graded ratio of aluminium to secondary element from its core or centre, with aluminium decreasing and the secondary element increasing in concentration. Thus, with an aluminium alloy containing magnesium, such as the alloy CA313, normal dendrite growth gives rise to dendrites which have an aluminium-rich core or centre but which, from the core or centre, have a decreasing aluminium content and an increasing magnesium content. However, the alloy element separation resulting from the CEP, in a metal flow system according to the present invention, gives rise to alloy element separation on the basis of density, and modification of the normal growth. This modification results in a fluctuating variation in alloy elements from the core or centre of the degenerate dendrite particles which, instead of being gradual and substantially uniform, is more of a decaying sinusoidal form. Thus, while the core or centre is richer in aluminium and relatively low in the secondary element, the secondary element first rises, then falls and thereafter can rise again in directions outwardly from the core or centre. Thus, with an aluminium alloy such as CA313, the particles are low in magnesium at the core or centre but, from there, the magnesium content initially increase relative to aluminium over about an initial third of the radius of the degenerate dendrite particles, then decrease relative to aluminium over about the second third of the radius, and thereafter increase again to the outer perimeter of the particles. This modification occurs in the CEP, and is able to be retained in primary particles with flow of the alloy into the die cavity. The fluctuating ratio of aluminium and secondary alloy elements in the degenerate dendrite primary particles results from the conditions generated by the CEP. Computer simulations of flow conditions through a CEP generating a striated or banded microstructure indicate that, with flow of alloy through a suitable form of CEP which achieves the indicated flow rates through the outlet of the CEP, intense pressure waves are generated in the alloy. The simulations indicate that the pressure waves are at a level of about ±400 MPa. It is known that pressure differences of the order of a few 100 kPa can cause separation of less and more dense elements of an alloy, such as magnesium and aluminium. The computer simulations therefore point to pronounced separation, with movement of a less dense element to high pressure pulses and of a higher density element to low pressure pulses. Moreover, the computer simulations suggest that the intense pressure waves will have a wavelength of about 40 μm. This is found to accord very closely with results achieved in practice. As indicated above, it is found that, for alloy solidified in a CEP under conditions providing for relatively rapid solidification in a die cavity, and back into the CEP, the resultant striations or bands in the microstructure of alloy solidified in the CEP have a wavelength of about 200 μm. That is, the spacing between centres for successive like bands, of primary element or secondary element, is about 40 μm. BRIEF DESCRIPTION OF THE DRAWINGS In order that the present invention may more readily be understood, reference now is made to arrangements illustrated in the accompanying drawings. FIG. 1 is a perspective view, from the engine end, of a conventional die cast automotive transmission case; FIG. 2 is a perspective view of the transmission case of FIG. 1 , taken from the gearbox end; FIG. 3 is a schematic side elevation of a production casting as in FIGS. 1 and 2 ; FIGS. 4 to 9 correspond to FIG. 3 but show respective experimental castings of transmission cases as in FIGS. 1 and 2 , each produced with a respective experimental metal flow system according to the present invention; FIG. 10 is a longitudinal sectional view illustrating a trial casting of complex form, using a metal flow system according to the present invention; FIG. 11 is a plan view of part of a die for pressure casting of aluminium alloy, illustrating a metal flow system according to the invention; FIG. 12 is a sectional view taken on line A—A of FIG. 11 ; FIG. 13 is a sectional view on line B—B of FIG. 11 ; FIG. 14 is a partial end elevation taken on line C—C of FIG. 11 ; FIG. 15 is a sectional view taken on line D—D of FIG. 11 ; FIG. 16 is a schematic representation of an experimental casting illustrating alloy travel with use of a metal flow system according to the present invention; FIG. 17 is a plan view of a casting produced according to the present invention as removed from the die tool in which it was produced; and FIG. 18 is a sectional view of the casting of FIG. 17 , before removal from the die tool, taken on line E—E of FIG. 17 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Experimental Example A trial, conducted to explore the practicability of casting an aluminium alloy product, using metal flow systems in accordance with the present invention, was conducted using an Ube 1250 t high pressure cold-chamber die casting machine at an automotive die casting plant. The trial involved casting automotive transmission cases from CA313 aluminium alloy. For this, six experimental flow paths were machined into respective cast runners which had been trimmed from production castings, to form six different metal flow systems according to the invention. By placing each of these runners, with its machined flow system, back into the die casting tool of the Ube casting machine, and casting through each flow system, respective transmission cases were cast. The runner/CEP shapes were designed to enable evaluation and comparison of various ways of directing the molten aluminium alloy into the die cavity by achieving high speed alloy flow through each runner/CEP before injection into the die cavity. The transmission cases were comparable in quality, and in one case superior, to production castings made with a conventional tapered tangential runner system which produced the trimmed runners subjected to machining. As detailed below, each experimental, machined flow path providing one of the six metal flow systems according to the invention was much smaller in cross-section and mass, demonstrating that it is possible and practical to produce large aluminium alloy die castings using flow systems which result in substantially less remelt from each casting, without loss of quality. As indicated above, runners were obtained from normal production of six high pressure die cast aluminium alloy automotive transmission cases produced Melt temperature: 635° C. Aluminium alloy: CA313 Approx wts (measured): Casting:  8.7 kg Runner:  0.75 kg Biscuit:  2.5 kg Total: 11.95 kg. The conditions were the same for the experimental trials, except that the runner metal solidified in the new runners ranged from about 0.05 kg to about 0.13 kg, in contrast to the 0.75 kg for the normal production castings. The Ube die casting machine used for the trials was in full production mode before the trial began. Each new runner/CEP was placed in the sliding cores of the die in respective casting operations and held there by a liberal amount of silicone sealant. Respective trial castings in accordance with the present invention, using each new runner/CEP, are illustrated schematically in FIGS. 4 to 9 . In each case, the shape of the respective new runner/CEP is shown and designated as R. However, for ease of illustration, the production runners drilled to provide each new runner/CEP is omitted from FIGS. 4 to 9 . Each production and experimental casting was examined using X-ray inspection techniques both in-plant, by production quality control personnel, and again by a more thorough laboratory examination. The results of the examination showed that the experimental castings made with each new runner/CEP was comparable to the castings made in normal production. One experimental casting contained the least amount of porosity of all castings examined, including normal production castings collected during the trial run. Sections were cut from the production and trial runner castings. Bosses at diagonally opposite corners of the castings were removed to examine the microstructure of the metal and the type of porosity present. The bosses were polished approximately 10 mm below the surface and parallel to the two mating flanges at either end of the casting. The polished bosses then were etched and examined under an optical microscope at magnifications up to 1000×. The locations of the bosses cut from each of the experimental castings for examination were the same as for the normal production castings. using a conventional tapered tangential runner system. FIGS. 1 and 2 are perspective views from the engine end E and the gearbox end G, respectively, of one of the transmission cases produced by a normal production cycle using the conventional tapered tangential runner system. In FIGS. 1 and 2 , the case is shown at 10 , with its still attached runner metal shown at 12 . In the schematic side elevation of FIG. 3 the sprue/runner metal 12 shown prior to being trimmed from the case 10 . As indicated, the sprue/runner metal 12 was carefully removed from a number of cases as in FIGS. 1 and 2 , produced in accordance with normal production practice. The runners were separated and collected, and as shown in FIG. 3 , the metal 12 was cut approximately on lines X—X to provide the collected runner metal sections 14 . The respective experimental flow path machined into each cast runner trimmed from a production casting, when placed, in turn, back into the die casting tool of the Ube machine, then became “a new runner/CEP” for casting a transmission casing. That is, the flow path provided a metal flow system according to the invention through which CA313 aluminium alloy flowed to reach the tool die cavity. Each of the six flow paths was designed to have reduced cross-sectional area to the die cavity, and to achieve high velocity metal flow into the cavity. During the trial, the settings for the Ube die casting machine were not changed from their production values. For example, plunger velocity remained as set for production cast of transmission cases using the conventional tapered tangential runner. As a result, a higher velocity (V r ) for alloy entry to the die cavity was the product of the plunger velocity (V b ) and the ratio of plunger cross-sectional area (A p ) to flow-path (i.e. new runner) cross-sectional area (A r ), as represented by: V r = V p · ( A p A r ) ⁢   . Between successive trial castings, using a metal flow system according to the invention, five production castings were made using the conventional tangential runner system. The third and fifth of the production castings were collected for examination and comparison with the trial castings. The casting conditions for normal production were as follows: Ube 1250 t high pressure die casting machine. The bosses were preferentially sectioned because they commonly contain porosity due to their thickness. The indicated locations for the particular bosses were chosen because they represented the two furthermost points from the runner at both ends, a location close to the runner and a location that X-ray inspection showed to commonly contains porosity. The third of the five normal production castings made between successive experimental castings was sectioned at the latter two locations to compare the microstructures with the experimental castings. The type of porosity observed in castings made during the trial was a combination of gas and shrinkage localised in the thicker boss sections. This is common in castings where the bosses are fed through a much thinner cavity section, in this case the 20 mm thick bosses were fed through a cavity section of 5.5 mm thick. There was no significant difference between the type of porosity found in trial castings and production castings, only variations in size, number and location. X-ray inspection of 57 locations around each casting showed that the porosity tended to localise at the centre of the bosses and in the thicker sections between bosses where shrinkage was most likely to occur. The porosity commonly appeared as a collection of small gas/shrinkage pores rather than a large shrinkage tear or a large isolated gas pore. Polished sections of bosses showed that pore numbers ranged from a few to around 100 within a boss and ranged in size from about 50 to 500 μm. Larger pores, 4 to 5 mm diameter, were sometimes found in both production and trial castings, these tended to be at locations where the flow during cavity fill may have trapped pockets of gas. Of the castings inspected, one trial casting (that depicted in FIG. 9 ) had porosity at approximately half the number of locations compared to the production castings and the porosity mostly consisted of fine dispersed gas/shrinkage. The other trial castings of FIGS. 4 to 8 were of similar quality to the production castings. Experience with current systems would lead to anticipation of more porosity in the experimental castings of FIGS. 4 to 9 using the new runners, than in production castings as in FIG. 3 which had been optimised over many years, but this did not occur. Overall the experimental castings illustrated by FIGS. 4 to 9 have shown that the transmission case could be made with a much reduced runner size at equal if not better casting quality. The new runner system R of FIG. 4 for producing an experimental casting 20 has a first straight-through channel R(a) from which a second channel R(b) extends substantially at right angles. The channels R(a) and R(b) are of 20 mm diameter and each ends in a respective CEP(a,b) of increasing tapered cross-section which opens to the die cavity for casting 20 . The runner system R of FIG. 5 is similar to that of FIG. 4 , except that channels R(a,b) are at an acute angle of about 50° and each is 9 mm in diameter. The system R of FIG. 6 has a single channel R(a) and CEP(a), although the channel R has sections mutually inclined at about 105° and is 20 mm in diameter. The arrangement of the runner system R of FIG. 7 is similar to that of FIG. 5 . However, the channel sections R(a) and R(b) are relatively short and of 9 mm diameter, and the lead in channel R(c) is cranked and of 12 mm diameter. The system R of FIG. 8 is similar to that of FIG. 4 except that it is of 12 mm diameter and channel branch R(a) is short and terminates at a blind end. FIG. 9 has an arrangement similar to that of FIG. 4 , except that channel sections R(a) and R(b) are 9 mm in diameter and lead in section R(c) is of 18 mm diameter. Also, in FIG. 9 , section R(c) joins section R(b) intermediate CEP(b) and the junction between sections R(a) and R(b), while CEP(b) increases in cross-section from that of runner section R(b) but is asymmetrical so as to have a relatively larger dimension axially of the die cavity for casting 40 . The experiment illustrated in FIGS. 4 to 9 , involving trial runner shapes and channels drilled into previously cast runners, makes clear that a reduction in runner size and hence a reduction in scrap, is able to be obtained without a loss of casting quality using the metal flow system of the present invention. The metal velocities through the experimental flow systems were higher than through conventional runner systems. Microscopic examination of sections from both production and experimental castings showed no significant difference in microstructure. This industrial experiment has shown that a transmission casting made in CA313 aluminium alloy could be made with a much reduced metal flow system with consequent savings in remelt cost and improved quality. With reference now to FIG. 10 , there is illustrated the production of castings 40 , made using CA313 aluminium alloy on 250 tonne Toshiba cold chamber machine. The casting 40 has broad, flat areas 42 , 43 and 44 , a difficult box shaped area 46 with cross-ribs 47 and bosses 48 and 49 . The casting had a length of 380 mm in the plane of the section of FIG. 10 and a width perpendicular to that plane of 150 mm, giving a projected area of 570 cm 2 . The die 50 used for casting 40 was designed to allow the option of feeding the three impressions A, B and C singly or in multiples. Each impression A, B and C has its own feeding bush F a , F b and F c respectively and its own temperature control, with main runner R m extending to all three of the feeding bushes. The impressions are able to be varied in position and, if required, spacers 52 of greater width can be used to isolate adjacent impressions. As is evident from FIG. 10 , casting 40 was produced using all three impressions. However, feed bushes F b and F c were blocked and all alloy feed was through a CEP defined at a CEP defined by bush F a , through impression A to impressions B and C. The casting filled without difficulty and was of good quality and definition throughout, with minimal porosity. Successive castings 40 were made using respective bushes F a , each defining a respective CEP. In each case, the runner R m was the same and comprised a channel of bi-laterally symmetrical trapezoidal cross-section. The channel had a depth of 4.5 mm and a mid-height width of 4.5 mm, giving a cross-sectional area of 20.25 mm 2 . Each bush had a tapered bore of circular cross-section which defined its CEP. Each CEP was 20 mm long, with a respective inlet and exit diameter and cross-sectional area as follows: Diameter (mm) Exit Area (mm 2 ) Bush Inlet Exit Inlet Exit I 4 6 12.6 28.3 II 5 7 19.6 38.5 III 7 9 28.5 63.6 Thus, the exit cross-sectional area of each CEP was substantially larger than the cross-sectional area of the runner R m . Even in the case of bush I, the CEP area was about 40% larger than the runner area. Bushes I and II each had an inlet cross-sectional area less than that of runner R m , although it is the exit area that is material. With each of bushes I, II and III, castings 40 of excellent quality were produced, despite the complex form. In a further trial, a short shot was made with the die of FIG. 10 to check the filling mode. This resulted in about a two-thirds casting through to region S in impression C. Again, the casting was of good quality and definition, with minimal porosity. The edge of the short shot casting at region S was in a near straight vertical line across the die cavity. The edge was of semi-rounded form. This unusual filling mode is typical of a “solid front fill” achieved with use of the present invention; that is, with high speed injection with the aluminium alloy in a semi-solid state. Turning now to FIGS. 11 to 15 , the die part 60 shown therein has a planar inner surface 62 by which it mates with a similar complementary part (not shown). The complementary die parts define a metal flow system according to the present invention, a major part of which is shown at 64 in FIG. 11 . The metal flow system 64 provides for metal flow between a casting machine nozzle (not shown), when the outlet end of the nozzle is applied against frusto-conical seat 66 defined in the outer face 60 a of part 60 , and a die cavity 68 (partly shown) which is defined in part by the inner surface 60 b of die part 60 . The system 64 includes a sprue channel 72 , leading inwardly from seat 66 , a runner system 74 extending from sprue bore 72 , and a CEP 76 at the inner end of system 64 which communicates with die cavity 68 . The die part 60 also has holes 78 which extend outwardly away from surface 62 , from respective locations within runner system 74 , with each of holes 78 able to accommodate an ejection pin (not shown) for use in ejecting sprue/runner metal attached to a casting produced in cavity 68 . One half of seat 66 is formed in die part 60 , with its other half formed in the complementary die part. However, beyond this, the other die part may have a planar surface free of any machining and which simply closes system 64 inwardly from seat 66 to die cavity 68 . The runner system 74 includes a main, transverse runner 80 which extends across the inner end of, and forms a T-shape with, sprue channel 72 . At each end, runner 80 has a respective end portion 80 a , with portions 80 a diverging from each other towards outer face 60 a of die part 60 . A respective one of ejector pin holes 78 communicates with each portion 80 a of runner 80 . System 74 also includes a secondary runner 82 which, at one end, extends from one of the portions 80 a of main runner 80 to CEP 76 , from a location intermediate the ends of portion 80 a. While the form of the part of seat 66 in die part 60 is semi-circular in cross-sections parallel to face 60 a of die part 60 , sprue channel 72 , CEP 7 b and runners 80 and 82 have cross-sections which are of substantially bi-laterally symmetrical trapezoidal form, although other geometries can be used. Sprue 72 and main runner 80 each have a cross-sectional area of about 66 mm 2 , while runner 82 has a cross-sectional area of about 14.4 mm 2 . CEP 76 , in a first part 76 a extending away from runner 82 , increases in width, but decreases in depth, such that its cross-sectional area increases from that of runner 82 to a maximum of about 16.3 mm 2 . From part 76 a to die cavity 68 , CEP 76 has a part 76 b of constant depth but, the effective width of part 76 b decreases due to part 76 b approaching inner surface 60 b of part 60 at an acute angle. However the overall effect is that the cross-sectional area of CEP 76 is greater than the area of runner 82 , such that aluminium alloy flowing through system 64 will have a greater flow velocity in runner 82 than in CEP 76 . With use of an aluminium alloy casting installation having the arrangement of FIGS. 11 to 15 , articles are able to be cast in successive casting cycles in die cavity 68 . With the die casting machine operating at its usual casting pressures for use with a current system, aluminium alloy, supplied by the machines nozzle applied to seat 66 , flows through sprue channel 72 and runner system 74 , and is injected into cavity 68 via CEP 76 . The relatively small cross-sectional areas of runners 80 and 82 is such that at the usual casting conditions, the flow velocity for aluminium alloy through the runners is able to be in a suitable range of 80 to 110 m.sec −1 . Similarly, the cross-sectional area of part 76 a of CEP 76 is such that the alloy flow velocity through CEP 76 is able to be in a suitable range of about 65 to 80 m.sec −1 . As a consequence, the alloy flow is turbulent. The turbulence is increased by the sharp change in flow direction for aluminium alloy passing from sprue channel 72 to runner 80 , into part 80 a of runner 80 and from the latter into runner 82 . It also is increased by the presence of alloy passing into the blind end of part 80 a , beyond the inlet end of runner 82 . Despite these matters, the indicated flow velocities, and the angle at which CEP 76 directs the alloy into die cavity 68 , good quality castings are able to be produced, whether at the higher or lower temperature conditions detailed earlier herein. FIG. 16 is a schematic representation of an experimental casting exercise, aimed at testing the distance aluminium alloy is able to travel during casting in accordance with the present invention, without freezing up. As shown in FIG. 16 , there was created a metal flow system S consisting of a channel C providing a metal flow path ending in a standard tensile bar impression B. The channel C had a nominal cross-section of 4×4 mm and a length of 1230 mm. Casting trials were carried out with the system S of FIG. 16 , on a 250 tonne cold chamber die casting machine. The trials were conducted under normal machine operating conditions for the machine, normal die temperatures and using a metal flow system similar to that of FIGS. 11 to 15 . As will be appreciated from FIG. 16 , the path of channel C is of a tortuous nature, creating high resistance to flow. Despite this, flow along the full 1230 mm length of the channel C was achieved, enabling filling of the bar impression B. The flow length of 1230 mm is considered not to be a limit. With reference to FIG. 17 , there is shown a casting, comprising an alternator casing 84 produced with a metal flow system according to the present invention. In successive casting cycles, respective casings 84 were cast, using either a single CEP or two CEPs. In the latter case, the two CEP were closely adjacent, and received alloy from a common runner. The runner/CEP arrangements are detailed more fully below. FIG. 18 shows the casing 84 prior to its release from a die tool 85 having a fixed die half 86 and a moving die half 87 . As seen by consideration of FIGS. 17 and 18 , casing 84 has a cylindrical peripheral wall 88 and, at one end of wall 88 , a transverse wall 89 . A number of windows 90 a to 90 g are defined by an annular outerpart 89 a of wall 89 , with wall 89 also having an outwardly recessed central part 89 b , and a bead 89 c within wall 88 around the junction of parts 89 a and 89 b . Also, to one side of the junction between walls 88 and 89 , casing 84 has a triangular formation 91 which defines windows 91 a . Casing 84 has a wall thickness of about 2.5 mm, while its internal diameter across wall 88 is about 112 mm. Successive casings 84 were cast on a 380 tonne Idra cold-chamber die casting machine from CA313 alloy. As ladled into the shot sleeve, the alloy was at about 630° C. In die tool 85 , alloy flow to the die cavity 85 a was via a runner 92 and either one or each of the two CEPs 93 . The form of the runner/CEP arrangement can be appreciated from the runner/CEP metal shown in FIG. 17 , in combination with the sectional detail of FIG. 18 . The runner had a cross-sectional area of about 18 mm 2 . Each CEP 93 had a square inlet end having a cross-sectional area of 17.6 mm 2 and an elongate rectangular outlet end having a cross-sectional area of 22.5 mm 2 . The length of each CEP was 27 mm. As shown by CEP metal 93 a in FIG. 17 , the two CEPs 93 were closely adjacent and somewhat in parallel. For castings in which only one of the CEPs 93 was used, the other one was blocked off, as represented by the CEP metal 93 a shown in broken outline in FIG. 17 . The die tool 85 was equipped with thermocouples in the moving die half 87 . While several castings were made with either two CEPs or with only one, it was found that the cooling system for tool 85 was inadequate for optimum tool temperature control over repeated casting cycles. To offset this, the machine injection pressure was reduced from the normal setting of 90 MPa to 50 MPa, and the plunger speed was set at 0.575 m/s average velocity with a peak at 0.96 m/s. At the start of the trials, with the two CEPs 93 used, the die tool temperature was 82° C. The first shot filled the die cavity completely. The second shot produced a cast alternator casing 84 of excellent quality. After some difficulties with ejection of castings, further trials were carried out with only one CEP in use, again with the resultant casings 84 of excellent quality. The trials were aborted after some 30 shots, due to ejection problems, although the trials established that casings 84 of excellent quality were able to be made. During the trials based on use of two CEPs 93 , the CEP inlet flow velocity was 54.8 m/s and the outlet velocity was 42.8 m/s. With trials based on use of one CEP, the CEP inlet flow velocity was 109.6 m/s, and the outlet flow velocity was 85.7 m/s. Thus, in each case, the flow of CA313 alloy through the or each CEP generated required alloy flow, and the microstructure of the castings 84 were of an optimum form as detailed herein. That is, the microstructure was characterised by fine, degenerate primary particles less than 40 μm, such as about 10 μm or less in a matrix of secondary phase. However, due to use of a cold-chamber machine, some larger dendrites up to about 100 μm were present, with these being carried through from the shot sleeve of the die casting machine. Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention.

A metal flow system, for use in casting aluminium alloy using a pressure casting machine, is provided by a component of a die or mould assembly, for the machine, which defines a die cavity. The component defines at least part of an alloy flow path for the flow of aluminium alloy from a pressurized source of substantially molten aluminium alloy of the machine to the die cavity. The flow path includes at least one runner and a controlled expansion port, referred to also as a CEP, which has an inlet through which the CEP is able to receive aluminium alloy from the runner and an outlet through which aluminium alloy is able to flow from the CEP for filling the die cavity. The CEP increases in cross-sectional area from the inlet to the outlet thereof to cause substantially molten alloy received into the runner to undergo a substantial reduction in flow velocity in its flow through the CEP whereby the aluminium alloy flowing through the CEP attains a viscous or semi-viscous state which is retained in filling the die cavity. A pressure casting machine includes the metal flow system, while the system also is used in a process for pressure casting of aluminium alloys.

SUMMARY OF THE INVENTION This invention is concerned with new compounds of the formula: ##STR3## wherein R 1 , R 2 and R 3 are each at the ortho or meta position, represent mono- or disubstituents and are selected from the group consisting of hydrogen, alkyl(C 1 -C 3 ), alkoxy(C 1 -C 3 ), trifluoromethyl and halogen; and R 4 is selected from the group consisting of alkyl(C 1 -C 3 ), alkenyl(C 2 -C 3 ), alkynyl(C 2 -C 4 ), cycloalkyl(C 3 -C 5 ), cycloalkyl(C 3 -C 6 )methyl, 4-oxopentyl, 3-tetrahydrofuranyl, 2,3-dihydro-1H-inden-1-yl, 1-alkyl(C 1 -C 3 )cyclopentyl, trans-2-alkyl(C 1 -C 3 )cyclopentyl, trans-2-alkoxy(C 1 -C 3 )cyclopentyl, 1-cyclopropylethyl, 2-methylcyclopropylmethyl, dicyclopropylmethyl, 2-, 3- or 4-pyridinylmethyl, 2-cyclopenten-1-yl, tetrahydro-2H-pyran-4-yl and cis and trans-2-methoxycyclohexyl; with the proviso that when R 4 is alkyl(C 1 -C 3 ), two of R 1 , R 2 and R 3 are not hydrogen. East German Pat. No. 137,716 covers a process for preparing N-substituted triorganophosphine imines which are stated to possess undisclosed biological utility. That patent discloses compounds of the above formula where R 1 , R 2 and R 3 are all hydrogen and R 4 is alkyl. Therefore, the proviso for R 4 eliminates these compounds from the generic formula of this invention. The method of treatment and composition of matter aspects of this invention include these compounds, however. R 4 is preferably methyl, ethyl, 2-, 3-, or 4-pyridinylmethyl, 3-tetrahydrofuranyl or cyclopropylmethyl. In one preferred embodiment, R 1 is 2-methyl, 2-ethyl, 2-chloro, 2-bromo, 2-fluoro or 2-trifluoromethyl and R 2 and R 3 are both hydrogen. In a second preferred embodiment R 1 and R 2 are the same and are 2-methyl or 2-chloro and R 3 is hydrogen. In another preferred embodiment R 1 is 3-chloro and R 2 and R 3 are both hydrogen. This invention is also concerned with new compounds of the formula: ##STR4## wherein R 1 , R 2 and R 3 are each at the ortho or meta position and are hydrogen or alkyl(C 1 -C 3 ); and X is an acid-addition salt such as sulfuric. This invention is also concerned with a method for effecting diuresis and lowering plasma renin activity in mammals as well as pharmaceutical compositions of matter containing these compounds and with processes for the preparation of these compounds. DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, there is provided a novel means of effecting diuresis, lowering plasma renin activity and increasing cardiac contractility in a mammal which comprises administering to said mammal a therapeutically effective amount of a compound selected from those of the above described Formula I. The compounds of Formula I find utility as diuretics and cardiotonics in mammals and as such may be used as the drug of choice for the treatment of edema caused by cardiac, hepatic, pulmonary and renal diseases, as well as drug-induced fluid and salt retention. These compounds may also be useful as hypotensive agents upon chronic administration by virtue of their diuretic activity. As cardiotonic agents, these compounds may likewise be useful in the treatment of congestive heart failure. Renin is a proteolytic enzyme which converts plasma angiotensinogen to angiotensin I. Angiotensin I, in turn is, enzymatically converted to angiotensin II, which constricts blood vessels and stimulates aldosterone production by the adrenal cortex, and latter leading to increased renal sodium retention and potassium excretion and expansion of extracellular volume. The action of the currently available diuretics can be depicted by the following diagram: ##STR5## In contrast, the compounds of the present invention acting on the kidney lower plasma renin activity, thereby effecting non-attenuated sodium loss and minimal potassium loss mediated in part by lack of adrenal compensatory aldosterine release. ##STR6## The compounds of this invention may be prepared as described in the following flowcharts and text. ##STR7## In accordance with Flowchart A, an alcohol (1), where R 4 is alkyl(C 1 -C 3 ), 2-propenyl or tetrahydro-3-furanyl, is reacted with a small portion of sodium hydride in dry acetonitrile until gas evolution ceases and then with carbonyldiimidazole (2) for 2-6 hours, giving the compounds (3), which are then reacted with hydrazine in acetonitrile for 8-24 hours at room temperature and evaporated to dryness, giving the hydrazine derivatives (4) which are then dissolved in a mixture of water and hydrochloric acid, cooled to 0°-5° C. and reacted with sodium nitrite, then extracted into ether as the azide derivatives (5) and finally reacted with a substituted triaryl phosphine, where R 1 , R 2 and R 3 are as described above, in ether for 1-4 hours at room temperature, giving the products (6), where R 4 is as described above. ##STR8## In accordance with Flowchart B, an alcohol (1), where R 4 is alkyl(C 1 -C 3 ), 2-propenyl or tetrahydro-3-furanyl, is reacted with phosgene to give the compounds (7) which may then either be reacted with hydrazine to give (4) and then with sodium nitrite to give (5), or may be reacted with sodium or lithium azide in acetonitrile to give (5) directly, followed by conversion to the products (6) as described in Flowchart A. ##STR9## In accordance with Flowchart C, a P,P,P-triphenylphosphine imide sulfate (8), where R 1 , R 2 and R 3 are a described above, and triethylamine in tetrahydrofuran reacted with carbonyldiimidazole (2), giving an N-(triphenylphosphoranylidene)-1H-imidazole-1-carboxamide (9) which is then reacted with an alcohol (1), where R 4 is as described above, and sodium hydride in 1,2-dimethoxyethane, giving the products (10). ##STR10## In accordance with Flowchart D a phosphine (11), where R 1 , R 2 and R 3 are as described above, is reacted with a carbonazidate (5), where R 4 is as described above, in ether, giving the products (10). ##STR11## In accordance with flowchart E, (the process of preparing phosphinimides described in "Houben-Weyl Methoden der Organischen Chemie", 4th Edition, Phosphor Verbindungen II, M. Regitz, ed.) a substituted triaryl phosphine, where R 1 , R 2 and R 3 are each at the ortho or meta position and are hydrogen or alkyl(C 1 -C 3 ) is reacted with O-hydroxylaminesulfonic acid in methanol, giving the phosphinimide sulfate salt. The sulfates may be easily converted to other acid-addition salts by simple chemistry. It is generally preferred that the respective product of each process step described in the above reaction schemes be separated and/or isolated prior to its use as starting material for subsequent steps. Separation and isolation can be effected by any suitable purification procedure such as evaporation, crystallization, column chromatography, distillation, etc. Also it should be appreciated that reaction times, temperatures and mole ratios are within the skill of the art. Lowering of Plasma Renin Activity in Normal Conscious Rats Compounds were tested for their ability to lower plasma renin activity of conscious, male Wistar rats (180-200 g, Charles River Labs.). Test agents were compounded in a mortar and pestle with 3% preboiled starch suspension. Rats were dosed orally by gavage with 25 mg/kg test agent in a dose volume of 2 ml/kg. At time zero and 1/3, 1, 3 and 6 hours relative to dosing, rats were sacrificed by decapitation and the first 3 seconds of blood collected in two chilled Vacutainer® tubes (Becton-Dickinson, Rutherford, N.J.) containing 40 μl of 150 mg/ml tripotassium EDTA. Plasma fractions, obtained by centrifugation for 20 minutes at 4° C. and 3000 G, were incubated (one of each pair at 37° C., the other at 4° C.) at pH 6.8 in 50 mM phosphate buffer to produce angiotensin I. The incubates contained peptidase inhibitors to prevent angiotensin I degradation and the buffer contained one mg/ml lysozyme (Sigma Grade III) used as an antiabsorbant. The incubates were diluted 20 fold in cold Tris buffer (pH adjusted to 7.4 with glacial acetic acid) also containing one mg/ml lysozyme, and then frozen. Diluted incubates were assayed within 3 days for angiotensin I content by radioimmunoassay according to a modification of the method of Haber, et al., J. Clin. Endocrin., 29, 1349-1355 (1969). Renin activity is calculated as the rate of production of angiotensin I (nanograms of angiotensin I/ml plasma/hour at 37° C.) less controls (rate at 4° C.). The results of this test on a representative compound of this invention appear in Table I. TABLE I______________________________________Percent Lowering of Plasma Renin Activity in NormalConcious Rats at Various Time Intervals FollowingAdministration of a Single 25 mg/kg Oral Dose of(Triphenylphosphoranylidene)carbamic Acid, Ethly EsterHours After Dose No. of Rats % Lowering______________________________________0 6 01/3 6 381 6 743 6 596 6 40______________________________________ Inhibition of evoked increase of plasma renin activity was determined by the following test. Compounds were tested for their ability to prevent drug-induced elevation of plasma renin activity (PRA) in concious, male Wistar rats (180-200 g, Charles River Lab.). PRA elevation was induced by a combined oral provacative treatment (C) of hydrochlorothiazide (10 mg/kg) and 1-(3-benzoyl-3-mercapto-2-methylpropionyl)-L-proline, acetate (U.S. Pat. No. 4,226,775) (one mg/kg), prepared by compounding in a mortar and pestle with preboiled 3% starch suspension. This treatment provided the daily maximum PRA. The daily minimum PRA was obtained from rats given oral starch suspension (S) alone. The magnitude of drug effect on PRA elevation was ascertained from rats pretreated orally with test agent (D), at the indicated doses, 30 minutes prior to administration of provacative treatment (C). The test agent was also compounded in preboiled 3% starch suspension. The dose volumes for both pretreatment and provocative treatment were 2 ml/kg. One hour after provocative treatment the rats were sacrificed by decapitation and the first 3 seconds of blood collected in two chilled Vacutainer® tubes (Becton-Dickinson, Rutherford, N.J.) containing 40 μl of 150 mg/ml tripotassium EDTA. The plasma fractions, obtained by centrifugation for 20 minutes at 4° C. and 3000 G, were incubated (one of each pair at 37° C., the other at 4° C.) at pH 6.8 in 50 mM phosphate buffer to produce angiotensin I. The incubates contained peptidase inhibitors to prevent angiotensin I degradation and the incubation buffer contained one mg/ml lysozyme (Sigma Grade III) used as an antiabsorbant. The incubates were diluted 20 fold in cold 100 mM Tris buffer (pH adjusted to 7.4 with glacial acetic acid) also containing one mg/ml lysozyme, and then frozen. Diluted incubates were assayed within 3 days for angiotensin I content by radioimmunoassay according to a modification of the method of Haber, et al., J. Clin. Endocrin., 29, 1349-1355 (1969). PRA is calculated as follows: PRA(ng AI/hour/ml plasma)=PRA 37° C.-PRA 4° C. Percent inhibition of PRA elevation is calculated as follows: ##EQU1## The results of this test on representative compounds of this invention appear in Table II. TABLE II______________________________________Percent Inhibition of Plasma Renin Elevation Average % Dose InhibitionCompound (mg/kg) (No. of Rats)______________________________________(Triphenylphosphoranylidene)- 25 80 (14)carbamic acid, ethyl ester 15 79 (6) 10 81 (6) 7 46 (5) 5 29 (5) 3 22 (5)(Triphenylphosphoranylidene)- 25 72 (3)carbamic acid, methyl ester(Triphenylphosphoranylidene)- 25 90 (3)carbamic acid, propyl ester(Triphenylphosphoranylidene)- 100 85 (8)carbamic acid, tetrahydro-3- 50 49 (8)furanyl ester 25 69 (5)(Triphenylphosphoranylidene)- 25 67 (3)carbamic acid 2-propenylester[(2-Methylphenyl)diphenyl- 25 92 (3)phosphoranylidene]carbamicacid, ethyl ester(Triphenylphosphoranylidene)- 25 40 (3)carbamic acid, 3-pyridinyl-methyl ester[(2-Methylphenyl)diphenyl- 25 93 (3)phosphoranylidene]carbamicacid, tetrahydro-3-furanylester[Bis(2-methylphenyl)phenyl- 25 54 (3)phosphoranylidene]carbamicacid, ethyl ester[(2-Methylphenyl)diphenyl- 25 75 (3)phosphoranylidene]carbamicacid, 3-pyridinylmethyl ester[Diphenyl[2-(trifluoromethyl)- 25 75 (3)phenyl]phosphoranylidene]-carbamic acid, ethyl ester[(2-Methylphenyl)diphenyl- 25 72 (3)phosphoranylidene]carbamicacid, cyclopropylmethyl ester[(2-Chlorophenyl)diphenyl- 25 96 (3)phosphoranylidene]carbamicacid, ethyl ester[(2,6-Dimethylphenyl)diphenyl- 25 68 (3)phosphoranylidene]carbamicacid, methyl ester[(2-Chlorophenyl)diphenyl- 25 98 (3)phosphoranylidene]carbamicacid, methyl ester[ Diphenyl[2-(trifluoromethyl)- 25 49 (2)phenyl]phosphoranylidene]-carbamic acid, methyl ester______________________________________ The diuretic activity of the compounds of this invention was also determined according to the method of Chan, P. S. and Poorvin, D., Sequential method for combined screening antihypertensive and diuretic agents in the same spontaneously hypertensive rat. Clinical and Experimental Hypertension, 1(6), 817-830 (1979). Male spontaneously hypertensive rats (SHR) of Okamoto strain, 16 weeks old, Taconic Farms Inc. were used in the test. These rats were kept on Purina laboratory chow and tap water ad libitum for 8 weeks before use. One male adult rat (about 300 g) was dosed by gavage with a test compound at 100 mg/kg together with 0.9% sodium chloride loading at 25 ml/kg at zero hour. The test compound was suspended in 3% preboiled starch at 50 mg/ml. The rat was put in a metabolism cage. The 0-5 hour urine was collected and urinary sodium and potassium were determined using a Beckman Astra 4. The effects of representative compounds of the invention according to this test appear in Table III expressed in milliequivalents (mEQ) of urinary sodium and potassium excreted. TABLE III______________________________________Diuretic Activity in Spontaneously Hypertensive Rats Vol- Potassium ume Sodium mEQ/5Compound ml mEQ/5 Hours Hours______________________________________(Triphenylphosphoranyli- 15.5 1.86 0.50dene)carbamic acid,ethyl ester(Triphenylphosphoranyli- 23.3 2.53 0.55dene)carbamic acid,methyl ester(Triphenylphosphoranyli- 12.5 1.37 0.48dene)carbamic acid, -n-propyl ester(Triphenylphosphoranyli- 14.8 1.10 0.70dene)carbamic acid, tet-rahydro-3-furanyl ester(Triphenylphosphoranyli- 13.3 1.17 0.67dene)carbamic acid, 2-propenyl ester(Triphenylphosphoranyli- 13.3 1.16 0.58dene)carbamic acid, 4-oxopentyl ester(Triphenylphosphoranyli- 14.5 1.47 0.60dene)carbamic acid,cyclobutylmethyl ester(Triphenylphosphoranyli- 13.0 1.41 0.87dene)carbamic acid, 2,3-dihydro-1 .sub.--H--inden-1-ylester(Triphenylphosphoranyli- 14.8 1.49 0.86dene)carbamic acid, 1-methylcyclopentyl ester(Triphenylphosphoranyli- 14.3 1.55 0.68dene)carbamic acid,trans-methylcyclopentylester(Triphenylphosphoranyli- 15.5 1.76 0.58dene)carbamic acid, 2-propynyl ester(Triphenylphosphoranyli- 12.5 1.34 1.01dene)carbamic acid,1-ethylcyclopentyl ester(Triphenylphosphoranyli- 19.5 2.00 0.57dene)carbamic acid,cyclopropylmethyl ester(Triphenylphosphoranyli- 17.0 1.83 0.72dene)carbamic acid,trans-2-methoxycyclo-pentyl ester(Triphenylphosphoranyli- 10.0 1.15 0.57dene)carbamic acid,2-butynyl ester[(2-Methylphenyl)diphen- 25.5 2.68 0.78ylphosphoranylidene]car-bamic acid, ethyl ester[(2-Methoxyphenyl)di- 11.3 1.31 0.97phenylphosphoranyli-dene]carbamic acid,ethyl ester(Triphenylphosphoranyli- 12.0 1.19 0.65dene)carbamic acid, 1-cyclopropylethyl ester(Triphenylphosphoranyli- 14.0 1.25 0.82dene)carbamic acid, 2-pyridinylmethyl ester(Triphenylphosphoranyli- 15.5 1.58 0.83dene)carbamic acid, 2-cyclopenten-1-yl esterester(Triphenylphosphoranyli- 13.3 1.38 0.73dene)carbamic acid,trans-2-ethoxycyclopentylester(Triphenylphosphoranyli- 16.5 1.50 0.70dene)carbamic acid, 4-pyridinylmethyl ester(Triphenylphosphoranyli- 10.3 1.14 0.63dene)carbamic acid, 1-propylcyclopentyl ester(Triphenylphosphoranyli- 14.5 1.60 1.00dene)carbamic acid, 2-pyridinylmethyl ester(Triphenylphosphoranyli- 11.3 1.28 0.47dene)carbamic acid, (2-methylcyclopropyl)methylester(Triphenylphosphoranyli- 15.3 1.60 0.64dene)carbamic acid,tetrahydro-2 .sub.--H--pyran-4-ylester[(2-Methylphenyl)diphen- 22.3 2.71 0.97ylphosphoranylidene]car-bamic acid, tetrahydro-3-furanyl ester(Triphenylphosphoranyli- 11.3 1.15 0.59dene)carbamic acid, cisand trans-2-methoxycy-clohexyl ester(Triphenylphosphoranyli- 12.8 1.45 0.67dene)carbamic acid,trans-2-methoxycyclo-hexyl ester(Triphenylphosphoranyli- 14.3 1.58 1.07dene)carbamic acid,dicyclopropylmethylester[Bis(2-methylphenyl)- 14.5 1.46 0.73phenylphosphoranyli-dene]carbamic acid,ethyl ester[(2-Methylphenyl)diphen- 12.3 1.48 0.62ylphosphoranylidene]car-bamic acid, 3-pyridinyl-methyl ester[Diphenyl[2-(trifluoro- 19.3 2.12 0.91methyl)phenyl]phosphor-anylidene]carbamic acid,ethyl ester[(2-Methylphenyl)diphen- 12.0 1.33 0.73ylphosphoranylidene]car-bamic acid, cyclopropyl-methyl ester[(2-Chlorophenyl)diphen- 19.5 2.05 0.71ylphosphoranylidene]car-bamic acid, ethyl ester[(2-Methylphenyl)diphen- 10.8 1.18 0.67ylphosphoranylidene]car-bamic acid, cyclopentylester[[(2,6-Dimethylphenyl)- 13.0 1.48 0.86diphenyl]phosphoranyli-dene]carbamic acid,ethyl ester[(2-Ethylphenyl)diphen- 19.0 2.07 0.78ylphosphoranyidene]car-bamic acid, ethyl ester[(2-Methylphenyl)diphen- 18.3 1.95 0.88ylphosphoranylidene]car-bamic acid, methyl ester[(2,6-Dimethylphenyl)- 12.8 1.33 0.84diphenylphosphoranyli-dene]carbamic acid,methyl ester[(2-Chlorophenyl)diphen- 20.0 2.30 0.94ylphosphoranylidene]car-bamic acid, methyl ester[Diphenyl[2-(trifluoro- 18.5 1.71 1.02methyl)phenyl]phosphor-anylidene]carbamic acid,methyl ester[Diphenyl[2-(trifluoro- 16.3 1.64 0.63methyl)phenyl]phosphor-anylidene]carbamic acid,tetrahydro-3-furanylester[(2-Chlorophenyl)diphen- 20.0 1.90 0.68ylphosphoranylidene]car-bamic acid, tetrahydro-3-furanyl ester[Bis(2-methylphenyl)- 13.5 1.45 0.76phenylphosphoranyli-dene]carbamic acid,methyl ester[(2-Ethylphenyl)diphen- 14.3 1.36 0.58ylphosphoranylidene]car-bamic acid, methyl ester[(3-Chlorophenyl)diphen- 23.8 2.32 0.64ylphosphoranylidene]car-bamic acid, ethyl ester[(3-Chlorophenyl)diphen- 23.0 2.45 0.60ylphosphoranylidene]car-bamic acid, methyl ester[Bis(2-chlorophenyl)- 22.3 2.40 0.38phenylphosphoranyli-dene]carbamic acid,ethyl ester(Triphenylphosphoranyli- 14.0 1.48 0.80dene)carbamic acid,cyclopentyl ester[(2-Bromophenyl)diphenyl- 22.5 2.51 0.68phosphoranylidene]car-bamic acid, ethyl ester[(3-Trifluoromethylphen- 13.5 1.38 0.67yl)phosphoranylidene]-carbamic acid, ethylester[bis(3-Chlorophenyl)- 18.3 1.84 0.89phenylphosphoranylidene]-carbamic acid, ethylester[(3-Fluorophenyl)diphen- 24.0 2.44 0.62ylphosphoranylidene]car-bamic acid, ethyl ester[ (2,3-Dichlorophenyl)- 14.3 1.83 0.86diphenylphosphoranyli-dene]carbamic acid ethylester[Bis(2-methylphenyl)- 13.5 1.45 0.76phenylphosphoranyl-idene]carbamic acid,methyl ester[Diphenyl(2-fluoro- 19.8 2.01 0.66phenyl)phosphoranyli-dene]carbamic acid,ethyl ester[[2-(1-Methylethyl)- 18.8 2.08 0.83phenyl]diphenyl-phosphoranylidene]-carbamic acid, ethylester[(3-Bromophenyl)- 12.4 1.16 0.78diphenylphosphoranyli-dene]carbamic acid,ethyl ester(Triphenylphosphoran- 14.5 1.60 1.00ylidene)carbamic acid,3-pyridinylmethyl ester(2-Methylphenyl)di- 16.3 1.88 0.68phenylphosphinimidesulfateTriphenylphosphinimide 12.0 1.25 0.65sulfate[Bis(2-methylphenyl)- 13.0 1.44 0.88phenyl]phosphinimidesulfate______________________________________ The effect of (triphenylphospharnylidene)carbamic acid, ethyl ester on cardiac contractility was determined by the following test. Isolated rat hearts were prepared and perfused essentially as described by Neely and Rovetto, Techniques for perfusing isolated rat hearts., in Methods of Enzymology, 24, part D, 43-60 (1975), J. G. Hardman and B. W. O'Malley (eds.), Academic Press, New York, N.Y. The hearts were cooled in ice cold saline and transferred to a Langendorff apparatus and perfused in a retrograde fashion with oxygenated Krebs-Henseleit buffer at 37° C. A 2-0 silk thread was secured to the left ventricular apex and run via pulleys to a force displacement transducer (Grass Instrument Co., model FT03C). Force of contraction (F), the first derivative of force with respect to time (dF/dt), and rate of cardiac contraction (HR) were monitored on a polygraph recorder (Grass Instrument Co., model 7D). The perfusion medium was a modified Krebs-Henseleit buffer of the following composition: ______________________________________Sodium chloride 119 mMPotassium chloride 4.7 mMCalcium chloride 2.54 mMMonobasic sodium phosphate 1.19 mMMagnesium sulfate 1.19 mMGlucose 5.5 mMSodium bicarbonate 25 mM______________________________________ This medium was equilibrated with 95% oxygen:5% carbon dioxide at 37° C. (Triphenylphosphoranylidene)carbamic acid, ethyl ester was dissolved in absolute ethanol at a concentration of 10 mg/ml and then diluted with Krebs-Henseleit buffer to the required stock concentration. The stock solution was infused at a constant rate by a syringe pump into the flow of buffer presented to the isolated heart at a rate necessary to achieve the desired final concentration. The results of this test appear in Table IV. TABLE IV__________________________________________________________________________Cardiodynamic Effects of (Triphenylphosphoranylidene)-carbamic Acid, Ethyl Ester in the Isolated PerfusedRat Heart PreparationFinal Drug No. of ConcentrationConcentration Rat Force (g) dF/dt(g/sec) HR(mg/liter) Hearts (mean % change) (mean % change) (mean % change)__________________________________________________________________________1 7 5 6 -34 6 18 16 -28 5 24 21 -2__________________________________________________________________________ The same effect has been achieved in anesthetized dogs by the intravenous administration of (triphenylphospharanylidene)carbamic acid, ethyl ester. The compounds of the present invention have been found to be highly useful for lowering plasma renin activity, as diuretics and as cardiotonic agents in mammals when administered in amounts ranging from about 1.0 mg to about 50.0 mg/kg of body weight per day. A preferred dosage regimen for optimum results would be from about 3.0 mg to about 20.0 mg/kg of body weight per day. Such dosage units are employed that a total of from about 200 mg to about 1400 mg of active compound for a subject of about 70 kg of body weight are administered in a 24 hour period. This dosage regimen may be adjusted to provide the optimum therapeutic response. For example, several divided doses may be administered daily or the dose may be proportionally reduced as indicated by the exigencies of the therapeutic situation. The compounds of this invention are preferably administered orally but may be administered in any convenient manner such as by the intravenous, intramuscular or subcutaneous routes, in appropriate quantities. The active compounds of the present invention may be orally administered, for example, with an inert diluent or with an assimilable edible carrier, or they may be enclosed in hard or soft shell gelatin capsules, or they may be compressed into tablets, or they may be incorporated directly with the food of the diet. For oral therapeutic administration, the active compounds may be incorporated with excipients and used in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Such compositions and preparations should contain at least 0.1% of active compound. The percentage of the compositions and preparations may, of course, be varied and may conveniently be between about 2% to about 60% of the weight of the unit. The amount of active compound in such therapeutically useful compositions is such that a suitable dosage will be obtained. The tablets, troches, pills, capsules and the like may also contain the following: A binder such as gum tragacanth, acacia, corn starch or gelatin; excipients such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; and a sweetening agent such as sucrose, lactose or saccharin may be added or a flavoring agent such as peppermint, oil of wintergreen, or cherry flavoring. When the dosage unit form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier such as a fatty oil. Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit. For instance, tablets, pills, or capsules may be coated with shellac, sugar or both. A syrup or elixir may contain the active compound, sucrose as a sweetening agent, methyl and propyl parabens as preservatives, a dye and flavoring such as cherry or orange flavor. Of course, any material used in preparing these dosage forms must be pharmaceutically pure and non-toxic. The invention will be described in greater detail in conjunction with the following non-limiting examples. EXAMPLE 1 (Triphenylphosphoranylidene)carbamic acid, ethyl ester A 26.0 g portion of ethyl carbazate was dissolved in 150 ml of ice/water and 25 ml of concentrated hydrochloric acid and stirred with ice bath cooling as 18 g of sodium nitrite in 50 ml of water was added dropwise during 20 minutes. This mixture was stirred in an ice bath for 2 hours then extracted with 250 ml of dichloromethane. The organic layer was separated, dried over magnesium sulfate and evaporated in vacuo at 30° C. to yield ethyl carbonazidate as a mobile liquid. This liquid was dissolved in 100 ml of ether, filtered and the filtrate added to a filtered solution of 66 g of triphenylphosphine in 400 ml of ether. This mixture was stirred vigorously (gas evolution) for one hour. The precipitate was collected, washed with ether and dried, giving 50.8 g of the desired literature product, mp. 135°-137° C. EXAMPLE 2 (Triphenylphosphoranylidene)carbamic acid, methyl ester The subject compound was prepared by the procedure of Example 1, using methyl carbonazidate in place of ethyl carbonazidate. It melted at 138°-139° C. EXAMPLE 3 (Triphenylphosphoaranylidene)carbamic acid, n-propyl ester A 12.2 g portion of n-propyl chloroformate in 150 ml of acetonitrile was stirred at 5°-10° C. as 7.0 g of sodium azide was added. This mixture was stirred for 18 hours and then filtered. The filtrate containing the n-propyl carbonazidate was stirred as a filtered solution of 24 g of triphenylphosphine in 200 ml of ether was added. This solution was stirred for 2 hours (gas evolution), then evaporated to an oil in vacuo at 30° C. This oil was stirred with 200 ml of ether for 1/2 hour; the crystalline product was collected, washed with two 75 ml portions of ether and dried, giving 14.1 g of the desired product, mp 90°-91° C. EXAMPLE 4 (Triphenylphosphoranylidene)carbamic acid, tetrahydro-3-furanyl ester A 4.4 g portion of 3-hydroxytetrahydrofuran was dissolved in 200 ml of dry acetonitrile. The solution was stirred as 100 mg of 50% sodium hydride in oil was added. This mixture was stirred until gas evolution ceased, then 8.1 g of carbonyldiimidazole was added. The mixture was stirred at room temperature for 3 hours. A solution of 1.8 g of 95% hydrazine in 100 ml of acetonitrile was prepared, dried over magnesium sulfate and added to the above solution of tetrahydro-3-furanyl 1-imidazole carboxylate, which was then stirred at room temperature overnight. This mixture was evaporated in vacuo at 40° C. to a glassy residue containing tetrahydro-3-furanyl carbonazidate. This solid was dissolved in a mixture of 150 ml of water and 15 ml of concentrated hydrochloric acid, cooled to 0±2° C. and stirred as a solution of 4 g of sodium nitrite in 50 ml of water was added dropwise. This mixture was stirred for 30 minutes at 0°-5° C. after addition was complete and then extracted with 150 ml of ether. The ether extract containing tetrahydro-3-furanyl carbonazidate was washed with 75 ml of saturated aqueous sodium bicarbonate, dried over magnesium sulfate and then added to a filtered solution of 13 g of triphenylphosphine in 150 ml of ether, with stirring (gas evolution). The mixture was stirred for 2 hours at room temperature, then the precipitate was collected, washed with 100 ml of ether and dried in vacuo at 60° C., giving 7.0 g of the desired product, mp 130°-131° C. Following the general procedure of Example 4, using the indicated starting materials, the products of Examples 5-7, found in Table V, were prepared. TABLE V______________________________________Ex. Starting Material Product MP° C.______________________________________5 2-propen-1-ol (triphenylphosphoranyli- 108-109 dene)carbamic acid, 2- propenyl ester6 cyclopentanol (triphenylphosphoranyli- 126-127 dene)carbamic acid, cyclopentyl ester7 4-oxopentan-1-ol (triphenylphosphoranyli- 73-75 dene)carbamic acid, 4- oxo-pentan-1-yl ester______________________________________ EXAMPLE 8 (Triphenylphosphoranylidene)carbamic acid, cyclopropylmethyl ester A mixture consisting of 0.75 g of cyclopropylmethanol, 0.48 g of 50% sodium hydride in mineral oil, and 50 ml of 1,2-dimethoxythane was stirred at room temperature for a few minutes, and then treated with 3.7 g of N-(triphenylphosphoranylidene)-1H-imidazole-1-carboxamide. The reaction mixture was stirred under reflux conditions for 6 hours, and then poured into 300 ml of ice-water. The precipitate was collected, washed with water, and dried in vacuo over phosphorus pentoxide at room temperature. Thin-layer chromatographic studies indicated that a single compound was present, but recrystallization from diethyl ether was also useful. A yield of 3.2 g of the desired compound was obtained, mp 107°-113° C. Following the general procedure of Example 8, using other starting materials in place of cyclopropylmethanol, the products of Examples 9-26 were obtained. In a few cases, preliminary purification by chromatography on silica gel, using a mixture of hexane and ethyl acetate as a developing solvent, was employed. TABLE VI______________________________________Ex. Starting Material Product MP °C.______________________________________ 9 trans-2-methyl- (triphenylphosphoranyli- 101-109 cyclopentanol dene)carbamic acid, trans-2-methylcyclopentyl ester10 2-propyn-1-ol (triphenylphosphoranyli- 103-106 dene)carbamic acid, 2- propynyl ester11 1-ethylcyclopent- (triphenylphosphoranyli- 84-90 anol dene)carbamic acid, 1- ethylcyclopentyl ester12 2,3-dihydro- (triphenylphosphoranyli- 124-128 1 .sub.--H--inden-1-ol dene)carbamic acid, 1,2,3-dihydro-1 .sub.--H--inden- 1-yl ester13 trans-2-methoxy- (triphenylphosphoranyli- 95-101 cyclopentanol dene)carbamic acid, trans-2-methoxycyclo- pentyl ester14 2-butyne-1-ol (triphenylphosphoranyli- 125-129 dene)carbamic acid, 2- butynyl ester15 1-cyclopropyl- (triphenylphosphoranyli- 79-84 ethanol dene)carbamic acid, 1- cyclopropylethyl ester16 2-cyclopenten-1-ol (triphenylphosphoranyli- 110-114 dene)carbamic acid, 2- cyclopenten-1-yl ester17 trans-2-ethoxy- (triphenylphosphoranyli- 116-118 cyclopentanol dene)carbamic acid, trans-2-ethoxycyclo- pentyl ester18 1-propylcyclopent- (triphenylphosphoranyli- 107-114 anol dene)carbamic acid, 1- propylcyclopentyl ester19 2-methylcyclopro- (triphenylphosphoranyli- 91-94 panemethanol dene)carbamic acid, (2- methylcyclopropyl)- methyl ester20 tetrahydro- (triphenylphosphoranyli- 138-142 2 .sub.--H--pyran-4-ol dene)carbamic acid, tetrahydro-2 .sub.--H--pyran- 4-yl ester21 cis and trans-2- (triphenylphosphoranyli- 92-98 methoxycyclohexanol dene)carbamic acid, cis- and trans-2-methoxy- cyclohexyl ester22 trans-2-methoxy- (triphenylphosphoranyli- 98-100 cyclohexanol dene)carbamic acid, trans-2-methoxycyclo- hexyl ester23 2-pyridinylmethanol (triphenylphosphoranyli- 86-88 dene)carbamic acid, 2- pyridinylmethyl ester24 4-pyridinylmethanol (triphenylphosphoranyli- 150-152 dene)carbamic acid, 4- pyridinylmethyl ester25 3-pyridinylmethanol (triphenylphosphoranyli- 108-110 dene)carbamic acid, 3- pyridinylmethyl ester26 dicyclopropyl- (triphenylphosphoranyli- 129-133 methanol dene)carbamic acid, dicyclopropylmethyl ester______________________________________ EXAMPLE 27 [(2-Methylphenyl)diphenylphosphoranylidene]carbamic acid, 3-pyridinylmethyl ester A mixture of 9.2 g of diphenyl(2-methylphenyl)phosphine in 65 ml of methanol was heated to solution on a steam bath, then cooled to room temperature. Over 5 minutes, a solution of 3.76 g of hydroxylamine-O-sulfonic acid in 24 ml of methanol was added. The mixture was filtered into 400 ml of ether and the solid collected giving 8.40 g of P-(2-methylphenyl)-P,P-diphenylphosphine imide, sulfate salt. The 8.40 g of the above compound was reacted with triethylamine and carbonyldiimidazole in tetrahydrofuran as described in Example 8, giving 5.35 g of 1-[[[(2-methylphenyl)diphenylphosphoranylidene]amino]carbonyl]-1H-imidazole. A 760 mg portion of 3-pyridinemethanol, 35 ml of 1,2-dimethoxyethane, 340 mg of 50% sodium hydride in oil and 2.7 g of 1-[[[(2-methylphenyl)diphenylphosphoranylidene]amino]carbonyl]-1H-imidazole were reacted as described in Example 8, giving 2.05 g of the desired product, mp 142°-143° C. Following the procedure of Example 27, using starting materials other than 3-pyridinemethanol, the products of Examples 28-30, foumd in Table VII, were obtained. TABLE VII______________________________________Ex. Starting Material Product MP °C.______________________________________28 cyclopropyl- [(2-methylphenyl)diphen- 110-112methanol ylphosphoranylidene]car- bamic acid, cyclopropyl- methyl ester29 cyclopentanol [(2-methylphenyl)diphen- 166-168 ylphosphoranylidene]car- bamic acid, cyclopentyl ester30 2-propyn-1-ol [(2-methylphenyl)diphen- 112-115 ylphosphoranylidene]car- bamic acid, 2-propyn-1- ol ester______________________________________ EXAMPLE 31 [(2-Methoxyphenyl)diphenylphosphoranylidene]carbamic acid, ethyl ester A 1.0 g portion of (2-methoxyphenyl)diphenylphosphine was added to 30 ml of ether and stirred. The mixture was filtered and to the filtrate was added 3.6 ml of 1M ethyl carbonazidate in ether. This mixture was repeatedly concentrated, treated with fresh ether and refrigerated, giving 400 mg of the desired product, mp 80°-83° C. EXAMPLE 32 [(2-Methylphenyl)diphenylphosphoranylidene]carbamic acid, tetrahydro-3-furanyl ester A 2.76 g portion of (2-methylphenyl)diphenylphosphine was stirred in 60 ml of ether, then treated with charcoal and filtered. To the filtrate was added a solution of 1.7 g tetrahydro-3-furanyl carbonazidate in 60 ml of ether. After standing 8 hours the solid was collected, washed with ether and dried, giving 2.3 g of the desired product, mp 118°-119° C. EXAMPLE 33 [(2-Methylphenyl)diphenylphosphoranylidene]carbamic acid, ethyl ester A solution of 1.0 g of (2-methylphenyl)diphenylphosphine in 30 ml of ether was treated with 4 ml of 1M ethyl carbonazidate in ether. The mixture was allowed to stand 48 hours, then repeatedly concentrated and finally treated with fresh ether and refrigerated, giving 930 mg of the desired compound, mp 113°-114° C. Following the procedure of Example 33, using the indicated phosphine and carbonazidate derivatives, the products of Examples 34-57, found in Table VIII were obtained. TABLE VIII__________________________________________________________________________ --Carbon-Ex. --Phosphine azidate Product MP °C.__________________________________________________________________________34 [2-(trifluoromethyl)- ethyl- [diphenyl[2-(trifluoromethyl)phenyl]- glass phenyl]diphenyl- phosphoranylidene]carbamic acid, ethyl ester35 [2-(trifluoromethyl)- methyl- [diphenyl[2-(trifluoromethyl)phenyl] 135-140 phenyl]diphenyl- phosphoranylidene]carbamic acid, methyl ester36 [2-(trifluoromethyl)- tetrahydro-3- [diphenyl[2-(trifluoromethyl)phenyl]- 102-104 phenyl]diphenyl- furanyl- phosphoranylidene]carbamic acid, tetra- hydro-3-furanyl ester37 (2-ethylphenyl)- methyl- [(2-ethylphenyl)diphenylphosphoranyli- 121-122 diphenyl- dene]carbamic acid, methyl ester38 (2,6-dimethylphenyl)- methyl- [(2,6-dimethylphenyl)diphenylphosphor- 149-151 diphenyl- anylidene]carbamic acid, methyl ester39 (2-methylphenyl)- methyl- [(2-methylphenyl)diphenylphosphoranyli- 139-142 diphenyl- dene]carbamic acid, methyl ester40 (2-chlorophenyl)- ethyl- [(2-chlorophenyl)diphenylphosphoranyli- 110-112 diphenyl- dene]carbamic acid, ethyl ester (dec.)41 (2-chlorophenyl)- tetrahydro-3- [(2-chlorophenyl)diphenylphosphoranyli- 118-120 diphenyl- furanyl- dene]carbamic acid, tetrahydro-3- (dec.) furanyl ester42 (3-chlorophenyl)- ethyl- [(3-chlorophenyl)diphenylphosphoranyli- 103-107 diphenyl- dene]carbamic acid, ethyl ester43 (3-chlorophenyl)- methyl- [(3-chlorophenyl)diphenylphosphoranyli- 99.5-100 diphenyl- dene]carbamic acid, methyl ester (dec.)44 bis(2-chlorophenyl)- ethyl- [bis(2-chlorophenyl)phenylphosphoran- 144-146 phenyl- ylidene]carbamic acid, ethyl ester45 (2-chlorophenyl)- methyl- [(2-chlorophenyl)diphenylphosphoranyli- 140-144 diphenyl- dene]carbamic acid, methyl ester46 bis(2-methylphenyl)- ethyl- [bis(2-methylphenyl)phenylphosphoran- 130-133 phenyl- ylidene]carbamic acid, ethyl ester47 [(2,6-dimethylphen- ethyl- [[(2,6-dimethylphenyl)diphenyl]phos- 119-120 yl)diphenyl]- phoranylidene]carbamic acid, ethyl ester48 (2-bromophenyl)- ethyl- [(2-bromophenyl)diphenylphosphoranyli- 113-114 diphenyl- dene]carbamic acid, ethyl ester49 (3-fluorophenyl)- ethyl- [[(3-fluorophenyl)diphenylphosphoran- 112-115 diphenyl- ylidene]carbamic acid, ethyl ester50 (2-ethylphenyl)- ethyl- [(2-ethylphenyl)diphenylphosphoranyli- 87-89 diphenyl- dene]carbamic acid, ethyl ester51 bis(3-chlorophenyl)- ethyl- [[bis(3-chlorophenyl)phenyl]phosphoran- 108-109 phenyl- ylidene]carbamic acid, ethyl ester52 (3-trifluoromethyl)- ethyl- [(3-trifluorophenyl)diphenylphosphoran- 85-87 phenyl-diphenyl- ylidene]carbamic acid, ethyl ester53 (2,3-dichlorophenyl)- ethyl- [(2,3-dichlorophenyl)diphenylphosphor- 134-136 diphenyl- anylidene]carbamic acid ethyl ester54 Diphenyl(2-fluoro- ethyl- [Diphenyl(2-fluorophenyl)phosphoranyli- 106-108 phenyl)- dene]carbamic acid, ethyl ester55 2-[(1-Methylethyl)- ethyl- [[2-(1-Methylethyl)phenyl]diphenylphos- 134-136 phenyl]diphenyl- phoranylidene]carbamic acid, ethyl ester56 (3-Bromophenyl)di- ethyl- [(3-Bromophenyl)diphenylphosphoranyli- 123-124 phenyl- dene]carbamic acid, ethyl ester57 [Bis(2-methylphenyl- methyl- [Bis(2-methylphenyl)phenylphosphoranyli- 140-142 phenyl- dene]carbamic acid, methyl ester__________________________________________________________________________ EXAMPLE 58 (2-Methylphenyl)diphenylphosphinimide sulfate Five grams of (2-methylphenyl)diphenylphosphine was dissolved in 35 ml of methanol by warming. Cooling to room temperature gave a suspension which was treated with a solution of 2 g of O-hydroxylaminesulfonic acid in 13 ml of methanol. A slight exothermic reaction resulted, the temperature rising from 22° C. to 29° C. during twenty minutes. After returning to room temperature, the reaction mixture was filtered into 220 ml of diethyl ether (vigorous stirring), resulting in the formation of a crystalline precipitate. This was filtered off, washed with diethyl ether, and dried, giving 3.4 g of the desired compound, mp 194°-196° C. EXAMPLE 59 Triphenylphosphinimide sulfate The subject compound was prepared by the procedure of Example 58, triphenylphosphine replacing the (2-methylphenyl)diphenylphosphine. It melted at 184°-190° C. with decomposition. EXAMPLE 60 [Bis(2-methylphenyl)phenyl]phosphinimide sulfate The subject compound was prepared by the procedure of Example 58, bis(2-methylphenyl)phenylphosphine relacing the (2-methylphenyl)diphenylphosphine. It melted at 194°-196° C. EXAMPLE 61 Preparation of Compressed Tablet ______________________________________Ingredient mg/Tablet______________________________________(Triphenylphosphoranylidene- 5-100carbamic acid, ethyl esterDibasic Calcium Phosphate NF qsStarch USP 40Modified Starch 10Magnesium Stearate USP 1-5______________________________________ EXAMPLE 62 Preparation of Hard Shell Capsule ______________________________________Ingredient mg/Capsule______________________________________(Triphenylphosphoranylidene)- 5-100carbamic acid, methyl esterLactose, Spray Dried qsMagnesium Stearate 1-10______________________________________ EXAMPLE 63 Intravenous Solutions An organic such as citric, succinic, tartaric or mixtures thereof is dissolved in water at a concentration of 0.1-0.75%. (Triphenylphosphoranylidene)carbamic acid, ethyl ester is dissolved in the acid-water mixture providing a clear solution which, after sterilization, is suitable for intravenous administration. EXAMPLE 64 Intramuscular Preparations (Triphenylphosphoranylidene)carbamic acid, ethyl ester is dissolved in one of the following solvents or cosolvents and then sterilized, providing solutions for intramuscular administration. ______________________________________Benzyl alcoholOlive oilPeanut oilPropylene glycol/water 20-80%Polyethylene glycol 300/water 20-100%Polyethylene glycol 400/water 20-100%Polyethylene glycol 4000/water 0.2-0.5%Ethanol/water 20-50%______________________________________ EXAMPLE 65 Oral Preparations (Triphenylphosphoranylidene)carbamic acid, ethyl ester is dissolved in one of the following systems providing solutions or suspensions for oral administration. ______________________________________Sodium lauryl sulfate/water 0.5-3%Polysorbate 80/water 0.5-5%Polysorbate 40/water 0.01-0.75%Polysorbate 20/water 0.005-0.02%Polyoxyethylene lauryl ether/water 0.5-4%Polyoxyethylene stearyl ether/water 0.5-4%Polyoxyethylene oleyl ether/water 0.5-4%______________________________________ EXAMPLE 66 Oral Suspension The following formulation provides an acceptable oral suspension. ______________________________________(Triphenylphosphoranylidene)- 1-5%carbamic acid, ethyl esterVeegum 0.1-2.0%Methyl paraben 0.08%Propyl paraben 0.02%Sucrose/Sorbitol 20-80%Flavor qsWater qs to 100%______________________________________

Novel triarylphosphinimide derivatives having the formula ##STR1## wherein R 1 , R 2 and R 3 are each at the ortho or meta position, represent mono- or disubstituents and are selected from the group consisting of hydrogen, alkyl(C 1 -C 3 ), alkoxy(C 1 -C 3 ), trifluoromethyl and halogen; and R 4 is selected from the group consisting of alkyl(C 1 -C 3 ), alkenyl(C 2 -C 3 ), alkynyl(C 2 -C 4 ), cycloalkyl(C 3 -C 5 ), cycloalkyl(C 3 -C 6 )methyl, 4-oxopentyl, 3-tetrahydrofuranyl, 2,3-dihydro-1H-inden-1-yl, 1-alkyl(C 1 -C 3 )cyclopentyl, trans-2-alkyl(C 1 -C 3 )cyclopentyl, trans-2-alkoxy(C 1 -C 3 )cyclopentyl, 1-cyclopropylethyl, 2-methylcyclopropylmethyl, dicyclopropylmethyl, 2-, 3- or 4-pyridinylmethyl, 2-cyclopenten-1-yl, tetrahydro-2H-pyran-4-yl and cis and trans-2-methoxycyclohexyl; with the proviso that when R 4 is alkyl(C 1 -C 3 ), R 1 , R 2 and R 3 may not each be hydrogen ##STR2## wherein R 1 , R 2 and R 3 are each at the ortho or meta position and are selected from hydrogen and alkyl(C 1 -C 3 ), and X is an acid addition salt; processes for producing them, compositions containing them, and methods for using them in mammals to effect diuresis; to lower plasma renin levels and to increase cardiac contractility.

BACKGROUND TO THE INVENTION The present invention relates to a series of new thiazolidine derivatives, which exhibit anti-diabetic activity in mammals, and provides methods and compositions using them, as well as processes for their preparation. Thiazolidine derivatives which can reduce blood sugar levels have been described, for example, in Japanese Patent Application Kokai No. Sho 55-22636 (Tokko No. Sho 62-42903), European Patent Publications No. 139 421 and 207 581, Japanese Patent Application Kokai No. Sho 61-36284 and No. Sho 62-5980 and Y. Kawamatsu et al., Chem. Pharm. Bull., 30, 3580-3600 (1982). These prior compounds all differ structurally from the compounds of the present invention. We have now discovered a series of new thiazolidine derivatives, which have a particularly good activity, in some cases much better than the prior compounds referred to above. In particular, the compounds of the present invention show a significant ability to suppress hepatic gluconeogenesis, which ability is expected to result in a level of reduction in fasting blood sugar levels which is substantially better than is achieved by the compounds disclosed in the prior art referred to above. BRIEF SUMMARY OF INVENTION It is, therefore, an object of the present invention to provide a series of new thiazolidine derivatives, which have the ability to reduce diabetic complications and which can, therefore, be used in the treatment and prophylaxis of various diseases and disorders arising from high blood sugar levels, for example hyperlipemia, diabetes and their complications. The compounds of the present invention are those compounds of formula (I): ##STR3## in which: A represents a group of formula (II) or (III): ##STR4## W represents a methylene group (>CH 2 ), a carbonyl group (>C═O) or a group of formula >C═N--OV in which V represents a hydrogen atom, a sulfo group, an acyl group as defined below or an alkyl group which has from 1 to 8 carbon atoms and which is unsubstituted or has at least one substituent selected from the group consisting of substituents (a), defined below; U represents a methylene group; or W is absent and U represents a carbon-carbon double bond between the group represented by A and the group --CR 1 (OH)--; R 1 represents a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms; R 2 and R 4 are independently selected from the group consisting of hydrogen atoms and alkyl groups having from 1 to 8 carbon atoms; R 3 represents a hydrogen atom or an alkyl group having from 1 to 10 carbon atoms; Y 1 and Y 2 are independently selected from the group consisting of hydrogen atoms and hydroxy-protecting groups, said hydroxy-protecting groups being preferably: aliphatic acyl groups having from 1 to 25 carbon atoms; halogenated alkanoyl groups having from 2 to 6 carbon atoms; alkoxyalkanoyl groups in which the alkoxy part has from 1 to 5 carbon atoms and the alkanoyl part has from 2 to 6 carbon atoms; alkenoyl or alkynoyl groups having from 3 to 6 carbon atoms; aromatic acyl groups in which the aryl part has from 6 to 14 ring carbon atoms and is a carbocyclic group, which is unsubstituted or has from 1 to 5 substituents selected from the group consisting of substituents (c), defined below; heterocyclic groups having 5 or 6 ring atoms, of which 1 or 2 are hetero-atoms selected from the group consisting of oxygen, sulfur and nitrogen atoms, which groups may be unsubstituted or may have at least one substituent selected from the group consisting of substituents (c), defined below, and oxygen atoms; tri-substituted silyl groups, in which all three or two or one of the substituents are alkyl groups having from 1 to 5 carbon atoms, and none, one or two of the substituents are aryl groups, as defined above; alkoxyalkyl groups, in which the alkoxy and alkyl parts each have from 1 to 5 carbon atoms; alkoxy-substituted alkoxymethyl groups in which each alkoxy part has from 1 to 5 carbon atoms; halogenated alkoxymethyl groups in which the alkoxy part has from 1 to 5 carbon atoms; halogenated ethyl groups; arylselenyl-substituted ethyl groups, in which the aryl part is as defined above; aralkyl groups in which the alkyl part has from 1 to 5 carbon atoms and the aryl part is a carbocyclic aryl group which has from 6 to 14 ring carbon atoms and which may be unsubstituted or substituted on the aryl part with an alkyl group, an alkoxy group, a nitro group, a halogen atom, a cyano group, or an alkylenedioxy group having from 1 to 3 carbon atoms; alkoxycarbonyl groups which have from 2 to 7 carbon atoms and which are unsubstituted or substituted with a halogen atom or a tri-substituted silyl group, as defined above; alkenyloxycarbonyl groups in which the alkenyl part has from 2 to 6 carbon atoms; sulfo groups; and aralkyloxycarbonyl groups, in which the aralkyl part is as defined above; n is 1, 2 or 3; said acyl group included in the definition of V is: an unsubstituted aliphatic acyl group which contains from 1 to 6 carbon atoms; a substituted aliphatic acyl group which contains from 2 to 6 carbon atoms and which is substituted with at least one substituent selected from the group consisting of substituents (b), defined below; an aromatic acyl group in which the aryl part is a carbocyclic aromatic ring which has from 6 to 14 ring carbon atoms and which is unsubstituted or has at least one substituent selected from the group consisting of substituents (c), defined below; or a heterocyclic acyl group having a heterocyclic ring containing 5 or 6 ring atoms, of which 1, 2 or 3 are hetero-atoms selected from the group consisting of nitrogen, oxygen and sulfur atoms, the heterocyclic ring being unsubstituted or having at least one substituent selected from the group consisting of substituents (c), defined below, and oxygen atoms; said substituents (a) are selected from the group consisting of alkoxycarbonyl groups having from 2 to 6 atoms, carboxy groups and carbocyclic aryl groups which have from 6 to 10 ring carbon atoms and which are unsubstituted or have at least one substituent selected from the group consisting of substituents (c), defined below; said substituents (b) are selected from the group consisting of halogen atoms and alkoxy groups having from 1 to 5 carbon atoms; said substituents (c) are selected from the group consisting of alkyl groups having from 1 to 5 carbon atoms, alkoxy groups having from 1 to 5 carbon atoms, halogen atoms, halogenated alkyl groups having from 1 to 3 carbon atoms, nitro groups, hydroxy groups, alkoxycarbonyl groups having from 2 to 6 carbon atoms and aryl groups which have from 6 to 10 ring carbon atoms and which are unsubstituted or have at least one substituent selected from the group consisting of substituents (d), defined below; and said substituents (d) are selected from the group consisting of alkyl groups having from 1 to 5 carbon atoms, alkoxy groups having from 1 to 5 carbon atoms, halogen atoms, halogenated alkyl groups having from 1 to 3 carbon atoms, nitro groups and hydroxy groups; and salts thereof. The invention also provides a pharmaceutical composition for the treatment or prophylaxis of diabetes or hyperlipemia, which comprises an effective amount of an active compound in admixture with a pharmaceutically acceptable carrier or diluent, wherein said active compound is selected from the group consisting of compounds of formula (I), defined above, and pharmaceutically acceptable salts thereof. The invention still further provides a method for the treatment or prophylaxis of diabetes or hyperlipemia in a mammal, which may be human, which method comprises administering to said mammal an effective amount of an active compound, wherein said active compound is selected from the group consisting of compounds of formula (I), defined above, and pharmaceutically acceptable salts thereof. The invention also provides processes for the preparation of the compounds of the present invention, which processes are described in more detail hereafter. DETAILED DESCRIPTION OF INVENTION Where substituents are referred to in general terms herein, without specifying the number thereof, there is, in principle, no limitation upon their number, except such as may be dictated by the number of substitutable positions, and possibly by steric constraints. However, in general, it may be said that from 1 to 5 such substituents are preferred, from 1 to 3 being more preferred, and 1 normally being most preferred. In the compounds of the invention, where R 1 represents an alkyl group, this may be a straight or branched chain alkyl group having from 1 to 8 carbon atoms, preferably from 1 to 4 carbon atoms. Examples of such alkyl groups include the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, hexyl, 1,3-dimethylbutyl, heptyl, octyl, 1-methylheptyl and 2-ethylhexyl groups. Of these, the methyl, ethyl and isobutyl groups are more preferred and the methyl group is most preferred. Where R 3 represents an alkyl group, this may be a straight or branched chain alkyl group having 1 to 10 carbon atoms, preferably from 1 to 8 carbon atoms, more preferably from 1 to 4 carbon atoms. Examples of such alkyl groups include the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl, 1,1-dimethylbutyl, 1,3-dimethylbutyl, heptyl, octyl, 1-methylheptyl, 2-ethylhexyl, 1,1,3,3-tetramethylbutyl, nonyl and decyl groups. Of these, the methyl and t-butyl groups are more preferred, the methyl group being most preferred. Where R 2 or R 4 represents an alkyl group, this may be a straight or branched chain alkyl group having from 1 to 8 carbon atoms, preferably from 1 to 3 carbon atoms. Examples of such alkyl groups include the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, hexyl, 1,3-dimethylbutyl, heptyl, octyl, 1-methylheptyl and 2-ethylhexyl groups. Of these, the methyl group is most preferred. Where V represents an alkyl group, it may be a straight or branched chain alkyl group having from 1 to 8 carbon atoms, preferably from 1 to 4 carbon atoms, and may optionally have substituents, preferably selected from the group consisting of substituents (a), defined above and exemplified below. Examples of such unsubstituted groups include the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, hexyl, 1,3-dimethylbutyl, heptyl, octyl, 1-methylheptyl and 2-ethylhexyl groups. Where the group is substituted, it preferably has from 1 to 5 substituents (depending upon the availability of substitutable positions) selected from the group consisting of substituents (a), i.e.: carbocyclic aryl groups which have from 6 to 10 ring carbon atoms, preferably 6 or 10, and most preferably 6, ring carbon atoms, and which may optionally be substituted by at least one substituent selected from the group consisting of alkyl groups having from 1 to 5 carbon atoms (e.g. the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl or isopentyl groups), halogen atoms (e.g. the chlorine, fluorine, bromine or iodine atoms) and alkoxy groups having from 1 to 5 carbon atoms (e.g. the methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, t-butoxy or pentyloxy groups); examples of such substituted and unsubstituted groups include the phenyl, p-methylphenyl, m-chlorophenyl and o-methoxyphenyl groups; the carboxy group; and alkoxycarbonyl groups having from 2 to 6 carbon atoms, such as the ethoxycarbonyl and t-butoxy-carbonyl groups. The preferred substituents (a) are the alkoxy-carbonyl groups having from 2 to 6 carbon atoms and the carboxy group, the carboxy group being most preferred. Of these substituted and unsubstituted alkyl groups, the methyl, alkoxycarbonylmethyl and carboxymethyl groups are the more preferred, the carboxymethyl group being most preferred. Where V represents an acyl group, it may be a straight or branched chain aliphatic acyl group containing from 1 to 6 carbon atoms, if unsubstituted, or from 2 to 6 carbon atoms, if substituted; and it preferably has from 2 to 6 carbon atoms in any event, more preferably from 2 to 4 carbon atoms. Examples of such groups include the acetyl, propionyl, butyryl and hexanoyl groups. Of these, the acetyl group is most preferred. Such a group may be, and preferably is, unsubstituted, or it may be substituted by at least one substituent selected from the group consisting of substituents (b), defined above and exemplified below, i.e. halogen atoms or alkoxy groups having from 1 to 5 carbon atoms. Examples of the groups and atoms which may be included in substituents (b) are: halogen atoms, such as the chlorine, fluorine, bromine and iodine atoms; and alkoxy groups having from 1 to 5 carbon atoms, such as the methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, t-butoxy and pentyloxy groups. Alternatively, where V represents an aromatic acyl group, the aromatic part of this is a carbocyclic aryl group which has from 6 to 14, preferably from 6 to 10, more preferably 6 or 10 and most preferably 6, ring carbon atoms and which is unsubstituted or has at least one substituent selected from the group consisting of substituents (c), defined above and exemplified below. Examples of such substituted and unsubstituted groups include the benzoyl, naphthoyl (1- or 2- naphthoyl), 3-methylbenzoyl, 2,4-dimethylbenzoyl, 4-ethylbenzoyl, 4-butylbenzoyl, p-anisoyl, 4-ethoxybenzoyl, 4-butoxybenzoyl, 3-chlorobenzoyl, 2-bromobenzoyl, 4-fluorobenzoyl, 4-trifluoromethylbenzoyl, 3-nitrobenzoyl, 2,4-dinitrobenzoyl, salicyloyl and 4-hydroxybenzoyl groups. Alternatively, where V represents a heterocyclic acyl group, this has 5 or 6 ring atoms, of which 1, 2 or 3 are hetero-atoms selected from the group consisting of nitrogen, oxygen and sulfur atoms, the heterocyclic ring being unsubstituted or having at least one substituent selected from the group consisting of substituents (c), defined above and exemplified below, and oxygen atoms. Where the heterocyclic ring has three hetero-atoms, we prefer that all three should be nitrogen atoms, or that one or two (preferably two) should be nitrogen atoms, and correspondingly two or one should be oxygen or sulfur atoms. Where the heterocyclic ring has two hetero-atoms, these are preferably different or both are nitrogen atoms, more preferably one of the hetero-atoms is a nitrogen atom and the other is selected from the group consisting of nitrogen, oxygen and sulfur atoms, still more preferably nitrogen and oxygen atoms. Examples of such groups include the 2-thenoyl, 3-furoyl, picolinoyl, 2-pyridinecarbonyl, nicotinoyl, isonicotinoyl, 4-isoxazolecarbonyl, 1-(1,2,3-triazolyl)-carbonyl, 2-, 3- or 4- piperidinylcarbonyl and 1-pyrrolidinylcarbonyl groups. Such groups may be, and preferably are, unsubstituted, or they may have one or more substituents selected from the group consisting of substituents (c), defined above and exemplified below. Where the group is substituted, the number of substituents is preferably from 1 to 5 (depending on the availability of substitutable positions), more preferably from 1 to 3, and most preferably 1. In general, the preferred groups and atoms represented by V are: a hydrogen atom; a sulfo group; an unsubstituted alkyl group having from 1 to 4 carbon atoms; a substituted alkyl group having from 1 to 4 carbon atoms in which the substituents are selected from the group consisting of aryl groups which have from 6 to 10 ring carbon atoms and which are unsubstituted or are substituted by at least one alkyl substituent having from 1 to 5 carbon atoms, carboxy groups and alkoxycarbonyl groups having from 2 to 6 carbon atoms; an aliphatic carboxylic acyl group having from 1 to 6 carbon atoms; or a carbocyclic aromatic carboxylic acyl group in which the aryl part has 6 or 10 ring carbon atoms, said group being unsubstituted or having at least one substituent selected from the group consisting of substituents (c), defined in Claim 1. Examples of groups and atoms which may be included in substituents (c) are: alkyl groups having from 1 to 5 carbon atoms, such as the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl and isopentyl groups; alkoxy groups having from 1 to 5 carbon atoms, such as the methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, t-butoxy, pentyloxy and isopentyloxy groups; halogen atoms, such as those illustrated above in relation to substituents (b); halogenated alkyl groups having from 1 to 3 carbon atoms, such as the chloromethyl, fluoromethyl, bromomethyl, iodomethyl, dichloromethyl, difluoromethyl, dibromomethyl, diiodomethyl, trichloromethyl, trifluoromethyl, tribromomethyl, triiodomethyl, 2-chloroethyl, 2-fluoroethyl, 2-bromoethyl, 2-iodoethyl, 2,2-dichloroethyl, 2,2-difluoroethyl, 2,2-dibromoethyl, 2,2-diiodoethyl, 2,2,2-trichloroethyl, 2,2,2-trifluoroethyl, 2,2,2-tribromoethyl and 2,2,2-triiodoethyl groups; nitro groups and hydroxy groups; alkoxycarbonyl groups having from 2 to 6 carbon atoms, as exemplified in relation to substituents (a); and aryl groups which are unsubstituted or have at least one substituent selected from the group consisting of substituents (d), defined below, as exemplified in relation to substituents (a). Where one or both of Y 1 and Y 2 represents a hydroxy-protecting group, there is no particular limitation on the nature of the protecting group, provided that it can act as a protecting group in the reaction for the preparation of the compound or in another reaction to which the compound is to be subjected, and that, where the compound is to be used therapeutically, it can readily be hydrolyzed in vivo and used as a pro-druq at the time of administration. Where the compound is to be used for non-therapeutic purposes, e.g. as an intermediate in the preparation of another compound, it is, of course, unnecessary that the protecting group should be selected with this requirement in mind, and it can be selected solely on the basis of its utility as a protecting group in the reaction. Examples of such protecting groups include: aliphatic acyl groups, preferably: alkanoyl groups having from 1 to 25 carbon atoms, more preferably from 1 to 20 carbon atoms, still more preferably from 1 to 6 carbon atoms, and most preferably from 1 to 4 carbon atoms, (such as the formyl, acetyl, propionyl, butyryl, isobutyryl, pivaloyl, valeryl, isovaleryl, hexanoyl, heptanoyl, octanoyl, lauroyl, myristoyl, tridecanoyl, palmitoyl and stearoyl groups, of which the acetyl group is most preferred); halogenated alkanoyl groups having from 2 to 6 carbon atoms, especially halogenated acetyl groups (such as the chloroacetyl, dichloroacetyl, trichloroacetyl and trifluoroacetyl groups); lower alkoxyalkanoyl groups in which the alkoxy part has from 1 to 5, preferably from 1 to 3, carbon atoms and the alkanoyl part has from 2 to 6 carbon atoms and is preferably an acetyl group (such as the methoxyacetyl group); and unsaturated analogs of such groups, especially alkenoyl or alkynoyl groups having from 3 to 6 carbon atoms [such as the acryloyl, methacryloyl, propioloyl, crotonoyl, isocrotonoyl and (E)- 2-methyl-2-butenoyl groups]; aromatic acyl groups, preferably arylcarbonyl groups, in which the aryl part has from 6 to 14, more preferably from 6 to 10, still more preferably 6 or 10, and most preferably 6, ring carbon atoms and is a carbocyclic group, which is unsubstituted or has from 1 to 5, preferably from 1 to 3 substituents, selected from the group consisting of substituents (c), defined above and exemplified below, preferably: unsubstituted groups (such as the benzoyl, α-naphthoyl and β-naphthoyl groups); halogenated arylcarbonyl groups (such as the 2-bromobenzoyl and 4-chlorobenzoyl groups); lower alkyl-substituted arylcarbonyl groups, in which the or each alkyl substituent has from 1 to 5, preferably from 1 to 4, carbon atoms (such as the 2,4,6-trimethylbenzoyl and 4-toluoyl groups); lower alkoxy-substituted arylcarbonyl groups, in which the or each alkoxy substituent preferably has from 1 to 5, preferably from 1 to 4, carbon atoms (such as the 4-anisoyl group); nitro-substituted arylcarbonyl groups (such as the 4-nitrobenzoyl and 2-nitrobenzoyl groups); lower alkoxycarbonyl-substituted arylcarbonyl groups, in which the or each alkoxycarbonyl substituent preferably has from 2 to 6 carbon atoms [such as the 2-(methoxycarbonyl)benzoyl group]; and aryl-substituted arylcarbonyl groups, in which the aryl substituent is as defined above, except that, if it is substituted by a further aryl group, that aryl group is not itself substituted by an aryl group (such as the 4-phenylbenzoyl group); heterocyclic groups having 5 or 6 ring atoms, of which 1 or 2 are hetero-atoms selected from the group consisting of oxygen, sulfur and nitrogen atoms, preferably oxygen or sulfur atoms, which groups may be unsubstituted or may have at least one substituent selected from the group consisting of substituents (c), defined and exemplified above, and oxygen atoms; the preferred heterocyclic groups have fully saturated ring systems; examples include: the tetrahydropyranyl groups, which may be substituted or unsubstituted, such as the tetrahydropyran-2-yl, 3-bromotetrahydropyran-2-yl and 4-methoxytetrahydropyran-4-yl groups; tetrahydrothiopyranyl groups, which may be substituted or unsubstituted, such as the tetrahydrothiopyran-2-yl and 4-methoxytetrahydrothiopyran-4-yl groups; tetrahydrofuranyl groups, which may be substituted or unsubstituted, such as the tetrahydrofuran-2-yl group; and tetrahydrothienyl groups, which may be substituted or unsubstituted, such as the tetrahydrothien-2-yl group; tri-substituted silyl groups, in which all three or two or one of the substituents are alkyl groups having from 1 to 5, preferably from 1 to 4, carbon atoms, and correspondingly none, one or two of the substituents are aryl groups, as defined above, but preferably phenyl or substituted phenyl groups, preferably: tri(lower alkyl)silyl groups (such as the trimethylsilyl, triethylsilyl, isopropyldimethylsilyl, t-butyldimethylsilyl, methyldiisopropylsilyl, methyldi-t-butylsilyl and triisopropylsilyl groups); and tri(lower alkyl)silyl groups in which one or two of the alkyl groups have been replaced by aryl groups (such as the diphenylmethylsilyl, diphenylbutylsilyl, diphenyl-t-butylsilyl, diphenylisopropylsilyl and phenyldiisopropylsilyl groups); alkoxyalkyl groups, in which the alkoxy and alkyl parts each have from 1 to 5, preferably from 1 to 4, carbon atoms, especially alkoxymethyl groups, and such groups which have at least one, preferably from 1 to 5, more preferably from 1 to 3, and most preferably 1, substituents, preferably: lower alkoxymethyl groups and other alkoxyalkyl groups (such as the methoxymethyl, 1,1-dimethyl-1-methoxymethyl, ethoxymethyl, propoxymethyl, isopropoxymethyl, butoxymethyl and t-butoxymethyl groups); lower alkoxy-substituted lower alkoxymethyl groups (such as the 2-methoxyethoxymethyl group); halogenated lower alkoxymethyl groups [such as the 2,2,2-trichloroethoxymethyl and bis(2-chloroethoxy)-methyl groups] and lower alkoxy-substituted ethyl groups (such as the 1-ethoxyethyl, 1-methyl-1-methoxyethyl and 1-isopropoxyethyl groups); other substituted ethyl groups, preferably: halogenated ethyl groups (such as the 2,2,2-trichloroethyl group); and arylselenyl-substituted ethyl groups, in which the aryl part is as defined above [such as the 2-(phenylselenyl)ethyl group]; aralkyl groups, preferably alkyl groups having from 1 to 4, more preferably from 1 to 3 and most preferably 1 or 2, carbon atoms which are substituted with from 1 to 3 aryl groups, as defined and exemplified above, which may be unsubstituted (such as the benzyl, phenethyl, 1-phenylethyl, 3-phenylpropyl, α-naphthylmethyl, β-naphthylmethyl, diphenylmethyl, triphenylmethyl, α-naphthyldiphenylmethyl and 9-anthrylmethyl groups) or substituted on the aryl part with a lower alkyl group, a lower alkoxy group, a nitro group, a halogen atom, a cyano group, or an alkylenedioxy group having from 1 to 3 carbon atoms, preferably a methylenedioxy group, [such as the 4-methylbenzyl, 2,4,6-trimethylbenzyl, 3,4,5-trimethylbenzyl, 4-methoxybenzyl, 4-methoxyphenyldiphenylmethyl, 2-nitrobenzyl, 4-nitrobenzyl, 4-chlorobenzoyl, 4-bromobenzyl, 4-cyanobenzyl, 4-cyanobenzyldiphenylmethyl, bis(2-nitrophenyl)methyl and piperonyl groups]; alkoxycarbonyl groups, especially such groups having from 2 to 7, more preferably from 2 to 5, carbon atoms and which may be unsubstituted (such as the methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl and isobutoxycarbonyl groups) or substituted with a halogen atom or a tri-substituted silyl group, e.g. a tri(lower alkylsilyl) group (such as the 2,2,2-trichloroethoxycarbonyl and 2-trimethylsilylethoxycarbonyl groups); alkenyloxycarbonyl groups in which the alkenyl part has from 2 to 6, preferably from 2 to 4, carbon atoms (such as the vinyloxycarbonyl and allyloxycarbonyl groups); sulfo groups; and aralkyloxycarbonyl groups, in which the aralkyl part is as defined and exemplified above, and in which the aryl ring, if substituted, preferably has one or two lower alkoxy or nitro substituents (such as the benzyloxycarbonyl, 4-methoxybenzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl, 2-nitrobenzyloxycarbonyl and 4-nitrobenzyloxycarbonyl groups). Of these, we prefer the aliphatic acyl groups having from 1 to 6 carbon atoms, the aromatic acyl groups and the sulfo group; more preferably the aliphatic acyl groups having from 2 to 4 carbon atoms, the unsubstituted aromatic acyl groups and the sulfo group; and most preferably the aliphatic acyl groups having from 2 to 4 carbon atoms, particularly the acetyl group. Examples of groups and atoms which may be included in substituents (d) are alkyl groups having from 1 to 5 carbon atoms, alkoxy groups having from 1 to 5 carbon atoms, halogen atoms, halogenated alkyl groups having from 1 to 3 carbon atoms, nitro groups and hydroxy groups, all as exemplified in relation to substituents (c). The compounds of the present invention necessarily contain at least one acidic hydrogen atom (at the 3-position of the thiazolidine ring) and may contain 1 or 2 further acidic hydrogen atoms (when Y 1 and/or Y 2 represents a hydrogen atom) and the compounds can, therefore, form salts with bases. There is no particular restriction on the nature of these salts, provided that, where they are intended for therapeutic use, they are pharmaceutically acceptable. Where they are intended for non-therapeutic uses, e.g. as intermediates in the preparation of other, and possibly more active, compounds, even this restriction does not apply. Examples of such salts include: salts with an alkali metal, such as sodium, potassium or lithium; salts with an alkaline earth metal, such as barium or calcium; salts with another metal, such as magnesium or aluminum; organic base salts, such as a salt with dicyclohexylamine; and salts with a basic amino acid, such as lysine or arginine. Where the cation is monovalent, for example, an alkali metal, the compounds of the present invention can form mono-, di- or tri-salts. Pharmaceutically acceptable salts are preferred. Also, where W represents a group of formula >C═N--OV, the resulting compounds may form salts with acids. There is no particular restriction on the nature of these salts, provided that, where they are intended for therapeutic use, they are pharmaceutically acceptable. Where they are intended for non-therapeutic uses, even this restriction does not apply. Examples of such salts include: salts with mineral acids, especially hydrohalic acids (such as hydrofluoric acid, hydrobromic acid, hydroiodic acid or hydrochloric acid), nitric acid, carbonic acid, sulfuric acid or phosphoric acid; salts with lower alkylsulfonic acids, such as methanesulfonic acid, trifluoromethanesulfonic acid or ethanesulfonic acid; salts with arylsulfonic acids, such as benzenesulfonic acid or p-toluenesulfonic acid; salts with organic carboxylic acids, such as acetic acid, fumaric acid, tartaric acid, oxalic acid, maleic acid, malic acid, succinic acid or citric acid; and salts with amino acids, such as glutamic acid or aspartic acid. The compounds of the present invention contain an asymmetric carbon atom at the 5-position of the thiazolidine ring and, where R 1 represents an alkyl group, the carbon atom to which R 1 is attached may also be asymmetric. The compounds can, therefore, form stereoisomers. Although these are all represented herein by a single molecular formula, the present invention includes the use of both the individual, isolated isomers and mixtures, including racemates, thereof. Where stereospecific synthesis techniques are employed or optically active compounds are employed as starting materials in the preparation of the compounds, individual isomers may be prepared directly; on the other hand, if a mixture of isomers is prepared, the individual isomers may be obtained by conventional resolution techniques, or the mixture may be used as it is, without resolution. Furthermore, the thiazolidine part of the compound of formula (I) can exist in the form of the tautomeric isomers shown below, but, in general, all of these tautomers are indicated herein by a single formula (I): ##STR5## The preferred compounds of the present invention are those compounds of formula (I) and salts thereof in which: A represents a group of formula (II) or (III), as defined above; W represents a methylene group, a carbonyl group or a group of formula ═C═N--OV in which V represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 4 carbon atoms or a substituted alkyl group having from 1 to 4 carbon atoms in which the substituents are selected from the group consisting of aryl groups which have from 6 to 10 ring carbon atoms and which are unsubstituted or are substituted by at least one alkyl substituent having from 1 to 5 carbon atoms, carboxy groups and alkoxycarbonyl groups having from 2 to 6 carbon atoms; U represents a methylene group; R 1 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R 2 and R 4 are the same or different and each represents a hydrogen atom or an alkyl group having from 1 to 3 carbon atoms; R 3 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; Y 1 and Y 2 are the same or different and each represents a hydrogen atom, an aliphatic acyl group having from 1 to 6 carbon atoms, an aromatic acyl group, as defined above, or a sulfo group; and n is 1 or 2. The more preferred compounds of the present invention are those compounds of formula (I) and salts thereof in which: A represents a group of formula (II) or (III), as defined above; W represents a methylene group or a group of formula ═C═N--OV in which V represents a hydrogen atom, an unsubstituted alkyl group having from 1 to 4 carbon atoms or a substituted alkyl group having at least one carboxy substituent; U represents a methylene group; R 1 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R 2 and R 4 are the same or different and each represents a hydrogen atom or an alkyl group having from 1 to 3 carbon atoms; R 3 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; Y 1 and Y 2 are the same or different and each represents a hydrogen atom, an aliphatic acyl group having from 2 to 4 carbon atoms, an unsubstituted aromatic acyl group or a sulfo group; and n is 1 or 2. The most preferred compounds of the present invention are those compounds of formula (I) and salts thereof, in which: A represents a group of formula (II) or (III), as defined above, particularly a group of formula (III): W represents a methylene group or a group of formula ═C═N--OV in which V represents a hydrogen atom, a carboxymethyl group or a 1-carboxy-1-methylethyl group, particularly a hydrogen atom, particularly we prefer that W should represent a methylene group; U represents a methylene group; R 1 represents a methyl group; R 2 and R 4 are the same or different and each represents a hydrogen atom or a methyl group; R 3 represents a methyl or t-butyl group, particularly a methyl group; Y 1 and Y 2 are the same and each represents a hydrogen atom or an aliphatic acyl group having from 2 to 4 carbon atoms, particularly a hydrogen atom or an acetyl group; and n is 1. Specific examples of the thiazolidine derivatives of the present invention are those compounds of formula (I-1) and (I-2), in which the substituents are as defined in the respective one of Tables 1 and 2, below, i.e. Table 1 relates to formula (I-1) and Table 2 relates to formula (I-2). In the Table, the following abbreviations are used: __________________________________________________________________________ Ac acetyl Boz benzoyl .sub.-iBu isobutyl .sub.-tBu t-butyl Et ethyl Me methyl Oc octyl Ph phenyl Pn pentyl .sub.-iPr isopropyl Sfo sulfo Tmb 1,1,3,3-tetramethylbutyl__________________________________________________________________________ ##STR6## (I-1) ##STR7## (I-2)__________________________________________________________________________ TABLE 1______________________________________Cpd.No. R.sup.1 R.sup.2 R.sup.3 R.sup.4 W -n______________________________________1-1 Me Me Me Me CH.sub.2 11-2 Me Me Me Me CH.sub.2 21-3 Me Me Me Me C═O 11-4 Me Me Me Me C═NOH 11-5 Me Me Me Me C═NOCOMe 11-6 Me Me Me Me C═NOCOPh 11-7 Me Me Me Me C═NOMe 11-8 Me Me Me Me C═NOCH.sub.2 Ph 11-9 Me Me Me Me C═NOCH.sub.2 ( -p-MePh) 11-10 Me Me Me Me C═NOCH.sub.2 COOH 11-11 Me Me Me Me C═NOCH.sub.2 COOEt 11-12 Me Me Me Me C═NOCMe.sub.2 COOH 11-13 Me H .sub.- tBu H CH.sub.2 11-14 Me H .sub.- tBu H CH.sub.2 21-15 Me H .sub.- tBu H C═O 11-16 Me H .sub.- tBu H C═NOH 11-17 Et Me Me Me CH.sub.2 11-18 .sub.- iBu Me Me Me CH.sub.2 11-19 .sub.- iBu Me Me Me C═O 11-20 Pn Me Me Me CH.sub.2 11-21 H Me Me Me CH.sub.2 11-22 Me H .sub.- iPr H CH.sub.2 11-23 .sub.- iBu H .sub.- tBu H CH.sub.2 11-24 Oc Me Me Me CH.sub.2 11-25 Oc Me Me Me C═O 11-26 Me H Tmb H CH.sub.2 11-27 Me H Tmb H CH.sub.2 21-28 Me H Tmb H C═O 11-29 Me H Tmb H C═NOH 11-30 .sub.- iBu H Tmb H C═NOCH.sub.2 COOH 11-31 Oc H Tmb H C═NOCH.sub.2 COOEt 1______________________________________ TABLE 2__________________________________________________________________________Cpd.No. Y.sup.1 Y.sup.2 R.sup.1 R.sup.2 R.sup.3 R.sup.4 W -n__________________________________________________________________________2-1 H H Me Me Me Me CH.sub.2 12-2 H H Me Me Me Me CH.sub.2 22-3 H H Me Me Me Me C═O 12-4 H H Me Me Me Me C═NOH 12-5 H H Me Me Me Me C═NOMe 12-6 H H Me Me Me Me C═NOCH.sub.2 COOH 12-7 H H Me Me Me Me C═NOC(Me).sub.2 COOH 12-8 H H Et Me Me Me CH.sub.2 12-9 H H Me H .sub.- tBu H CH.sub.2 12-10 H H H H H H CH.sub.2 12-11 H H .sub.- iBu H H H C═O 12-12 Ac Ac Me Me Me Me CH.sub.2 12-13 Ac Ac Me Me Me Me CH.sub.2 22-14 Ac Ac Me Me Me Me C═O 12-15 Ac Ac Et Me Me Me C═NOH 12-16 Ac H Me Me Me Me CH.sub.2 12-17 Sfo H Me Me Me Me CH.sub.2 12-18 H Ac Me Me Me Me CH.sub.2 12-19 H Sfo Me Me Me Me CH.sub.2 12-20 Sfo Sfo Me Me Me Me CH.sub.2 12-21 Boz Boz Me Me Me Me CH.sub.2 1__________________________________________________________________________ Of the compounds of the present invention, Compounds No. 1-1, 1-2, 1-4, 2-1, 2-4, 2-12, 2-13, 2-17 and 2-19 are preferred. The more preferred compounds are Compounds No.: 1-1. 5-{4-[2-hydroxy-2-methyl-4-(3,5,6-trimethyl-1,4-benzoquinon-2-yl)butoxy]benzyl}-2,4-dioxothiazolidine; 2-1. 5-{4-[4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutoxy]benzyl}-2,4-dioxothiazolidine; and 2-12. 5-{4-[4-(2,5-diacetoxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutoxy]benzyl}-2,4-dioxothiazolidine. Of these, the most preferred compound is Compound No. 1-1. The compounds of the present invention may be prepared by a variety of methods well known for the preparation of compounds of this type. For example, in general terms, they may be prepared by the following steps: (a) oxidizing a compound of formula (IV): ##STR8## (in which R 1 , R 2 , R 3 , R 4 , U, W and n are as defined above), to give a compound of formula (V): ##STR9## (in which R 1 , R 2 , R 3 , R 4 , U, W and n are as defined above); (b) if required, reducing said compound of formula (V), to give a compound of formula (VI): ##STR10## (in which R 1 , R 2 , R 3 , R 4 , U, W and n are as defined above); (c) if required, protecting the hydroxy groups in the compound produced in any of steps (b), (d) or (e) to give a compound of formula (I) in which one or both of Y 1 and Y 2 represent hydroxy-protecting groups; (d) if required, converting a group represented by W in the compound produced in any of steps (a), (b), (c) or (e) to any other group so represented; and (e) if required, salifying the compound produced in any of steps (a), (b), (c) and (d). In step (a) of the above sequence, a compound of formula (V) is prepared by oxidizing a compound of formula (IV). The compound of formula (IV) is a kncwn compound and is described, for example, in European Patent Publications No. 139 421 and 207 581, and in Japanese Patent Application Kokai No. Sho 61-36284, the disclosures of which are incorporated herein by reference. The oxidation reaction may be carried out using any oxidizing agent known for the ring-opening oxidation of chromans and related compounds to benzoquinones, and examples of such oxidizing agents include: trivalent iron salts, such as ferric chloride, ferric bromide or ferric sulfate; divalent copper salts, such as cupric sulfate, cupric chloride or cupric acetate; and organic free radicals, such as compounds having an N-oxyl group, for example 2,2,6,6-tetramethylpiperidine-1-oxyl or 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl. The reaction is normally and preferably carried out using from 0.5 to 15 moles, more preferably from 2 to 8 moles of the oxidizing agent per mole of the starting material of formula (IV). The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: ketones, such as acetone or methyl ethyl ketone; alcohols, such as methanol or ethanol; or a mixture of any one or more of these organic solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° C. to 50° C., more preferably from 15° to 30° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from a few minutes to 30 hours, more preferably from 3 minutes to 20 hours, will usually suffice. The resulting compound of formula (V) is a compound of the present invention and may be the desired final product. However, if it is desired to prepare a compound of formula (I) in which A represents a group of formula (II) and Y 1 and Y 2 both represent hydrogen atoms, i.e. a compound of formula (VI), this can be prepared by reduction of the compound of formula (V) in step (b). The reduction reaction may be carried out by contacting the compound of formula (V) with a suitable reducing agent. There is no particular restriction on the nature of the reducing agent employed in this reaction, and any reducing agent capable of reducing a benzoquinone to a dihydroxybenzene compound may equally be employed here. Examples of especially suitable reducing agents include the metal borohydrides, especially alkali metal borohydrides, such as sodium borohydride or potassium borohydride. The amount of reducing agent is not critical to the reaction, although, for economy, it is preferred that the amount should be at least equimolar with respect to the compound of formula (V). In general, the reaction is normally carried out using from 1 to 20 moles, and preferably a large excess of the reducing agent, per mole of the compound of formula (V). The reaction is normally and preferably effected in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol, ethanol, propanol, butanol or ethylene glycol monomethyl ether; and ethers, such as tetrahydrofuran or dioxan. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° C. to 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvent. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from a few minutes to 30 hours will usually suffice. In step (b), where W represents a carbonyl group, the reduction may be carried out without protecting the carbonyl group, but we prefer that the carbonyl group should be protected prior to this reaction. There is no particular restriction on the nature of the carbonyl-protecting group, provided that it has no adverse effect on the reduction reaction. Examples of suitable carbonyl-protecting groups include those groups of formula --X--(CH 2 ) p --X-- (in which X represents an oxygen or sulfur atom and p is 2 or 3), for example the ethylenedioxy, trimethylenedioxy, ethylenedithio and trimethylenedithio groups. Such protecting groups can be derived from the corresponding glycols of formula H--X--(CH 2 ) p --X--H, for example ethylene glycol, trimethylene glycol, ethylene dithioglycol or trimethylene dithioglycol, in the presence of an acid catalyst, such as hydrogen chloride or sulfuric acid. The compounds having a protected carbonyl group may then be subjected to reduction, as described above, after which the protecting group may be removed according to conventional means to afford the desired compound of formula (VI). Where W represents a group of formula ═C═N--OV (in which V is as defined above), the desired compound of formula (VI) can be prepared by reduction as described above in step (b), keeping the group of formula ═C═N--OV intact. However, we prefer instead to prepare the corresponding compound of formula (VI) in which W represents a carbonyl group, and then to convert that carbonyl group to the group of formula ═C═N--OV. This may be achieved by reacting the compound of formula (VI) in which W represents a carbonyl group with an oximating agent, for example a hydroxylamine of formula H 2 N--OV (in which V is as defined above) or with a salt thereof, which may be a salt with an inorganic or organic acid. The reaction may be carried out according to the procedure described in European Patent Publication No. 207 581. In the reaction of the compound of formula (VI) in which W represents a carbonyl group with a hydroxylamine of formula H 2 N--OV (in which V is as defined above), there is no particular limitation on the molar ratio of the reagents to each other. However, we prefer that the reaction should be carried out using an equimolar amount or an excess, preferably a large excess of the oximating agent, e.g. from 1 to 50 moles of hydroxylamine per mole of the compound of formula (VI). Where the hydroxylamine of formula H 2 N--OV is employed in the form of a salt of an inorganic acid, the reaction is preferably carried out in the presence of an acid-binding agent. Examples of suitable acid-binding agents include: alkali metal hydroxides, such as sodium hydroxide or potassium hydroxide; and alkali metal carbonates, such as sodium carbonate or potassium carbonate. The amount of the acid-binding agent employed is preferably not more than one mole equivalent per mole of the inorganic acid salt. The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol, ethanol, propanol, butanol or ethylene glycol monomethyl ether; ethers, such as tetrahydrofuran or dioxan; amides, especially dialkylformamides, such as dimethylformamide or dimethylacetamide; sulfoxides, such as dimethyl sulfoxide; sulfones, such as sulfolane; organic bases, such as triethylamine or pyridine; water; or a mixture of any two or more of these solvents. The reaction can take place over a wide range of temperatures, and the precise reaction temperature employed is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° to 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvent. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from a few minutes to about 10 days will usually suffice. The compound of formula (VI) in which W represents a carbonyl group can, if desired, be prepared by treating the corresponding compound of formula (VI) in which W represents a group of formula ═C═N--OV (in which V is as defined above) with an acid. Suitable acids include inorganic acids, such as hydrochloric acid, hydrobromic acid or sulfuric acid. The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol, ethanol, propanol, butanol or ethylene glycol monomethyl ether; ethers, such as tetrahydrofuran or dioxan; amides, especially dialkylformamides, such as dimethylformamide or dimethylacetamide; sulfoxides, such as dimethyl sulfoxide; sulfones, such as sulfolane; organic bases, such as triethylamine or pyridine; water; or a mixture of any two or more of these solvents. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 20° to 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from a few minutes to a few days will usually suffice. In step (c), one or both of the hydroxy groups of the compounds [formula (I) in which Y 1 and Y 2 both represent hydrogen atoms] can be protected by conventional means. As is well known in the art, the nature of the reaction employed to protect these groups will depend on the nature of the protecting group to be introduced. For example, where the hydroxy-protecting group is an aliphatic or aromatic acyl group, the reaction can be carried out by using an acylating agent, e.g. as described in European Patent Publication No. 207 581. That is to say, acylation can be carried out using a reactive derivative of the organic acid corresponding to the acyl group which it is desired to introduce, for example an acid anhydride or acid halide thereof. There is no particular limitation on the molar ratio of the acylating agent to the starting material, but the reaction is preferably carried out using a molar excess of the acylating agent, preferably from 1 to 10 moles of the acylating agent per mole of the starting material. The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, tetrahydrofuran or dioxan; aromatic hydrocarbons, such as benzene, toluene or xylene; aliphatic and cycloaliphatic hydrocarbons, such as hexane, cyclohexane or heptane; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as methylene chloride or chloroform; organic bases, such as pyridine or triethylamine; amides, especially dialkylformamides, such as dimethylformamide or dimethylacetamide; sulfoxides, such as dimethyl sulfoxide; sulfones, such as sulfolane; water; or a mixture of any two or more of these solvents. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° to 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from a few minutes to about 20 hours will usually suffice. Where the hydroxy-protecting group is a heterocyclic group such as a tetrahydropyranyl, tetrahydrothiopyranyl, tetrahydrofuranyl or tetrahydrothienyl group, the protection reaction may be effected by reacting the starting material with a corresponding heterocyclic compound, such as dihydropyran, dihydrothiopyran, dihydrothiophene or 4-methoxy-5,6-dihydro(2H)pyran. The reaction is normally and preferably carried out in the presence of a small amount of an inorganic acid, such as hydrochloric acid, sulfuric acid, phosphoric acid or phosphorous oxychloride, or of an organic acid, such as p-toluenesulfonic acid, trifluoroacetic acid, picric acid or benzenesulfonic acid. The reaction is also normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: ethers, such as tetrahydrofuran; nitriles, such as acetonitrile; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as chloroform or methylene chloride; and amides, especially dialkylformamides, such as dimethylformamide. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° C. to about room temperature. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvents to be employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 30 minutes to about 8 hours will usually suffice. Where the hydroxy-protecting group is a silyl group, the protection reaction can be effected by reacting the starting material with a silyl compound, whose nature depends on the nature of the protecting group to be introduced, preferably a silyl halide, more preferably chloride, such as trimethylsilyl chloride, dimethyl-t-butylsilyl chloride or diphenyl-t-butylsilyl chloride. The reaction is preferably carried out in the presence of an organic base, such as triethylamine, dimethylaminopyridine, imidazole or pyridine, or of a sulfide, such as lithium sulfide. The reaction is also normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: ethers, such as tetrahydrofuran; nitriles, such as acetonitrile; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as chloroform or methylene chloride; amides, especially dialkylformamides, such as dimethylformamide; and organic bases, such as triethylamine or pyridine. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° C. to about room temperature. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvents to be employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 30 minutes to about 8 hours will usually suffice. Where the hydroxy-protecting group is an alkoxyalkyl or aralkyl group, the protection reaction can be effected by reacting the starting material with an alkoxyalkylating or aralkylating agent. The reaction may be carried out according to the procedure described in European Patent Publication No. 207 581. That is, the reaction is carried out using an alkoxyalkyl halide (preferably the bromide), such as chloromethyl methyl ether, as the alkoxyalkylating agent or using an aralkyl halide (preferably the bromide), such as benzyl chloride or benzyl bromide, as the aralkylating agent. There is no particular limitation on the molar ratio of the alkoxyalkylating or aralkylating agent to the starting material, but the reaction is preferably effected using a molar excess of the alkoxyalkylating or aralkylating agent, preferably from 1 to 10 moles of the alkoxy-alkylating or aralkylating agent per mole of the starting material. The reaction is preferably carried out in the presence of a base, the nature of which is not critical, provided that it does not adversely affect other parts of the molecule. Examples of suitable bases include: alkali metal carbonates or bicarbonates, such as sodium carbonate, potassium carbonate, sodium bicarbonate or potassium bicarbonate; alkali metal hydroxides or alkaline earth metal hydroxides, such as sodium hydroxide, potassium hydroxide or calcium hydroxide; alkali metal hydrides, such as sodium hydride or potassium hydride; alkali metal alkoxides, such as sodium methoxide, sodium ethoxide or potassium t-butoxide; organic lithium compounds, such as butyl lithium or t-butyl lithium; lithium dialkylamides, such as lithium diisopropylamide or lithium dicyclohexylamide; and organic bases, such as pyridine or triethylamine. Of these, the alkali metal carbonates, such as potassium carbonate, are preferred. The reaction is preferably carried out using from 1 to 10 moles of the base per mole of the starting material, and the reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, tetrahydrofuran or dioxan; aliphatic hydrocarbons, such as hexane, heptane or cyclohexane; aromatic hydrocarbons, such as benzene, toluene or xylene; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as methylene chloride or chloroform; alcohols, such as methanol, ethanol or t-butanol; ketones, such as acetone or methyl ethyl ketone; organic bases, such as pyridine or triethylamine; amides, such as dimethylformamide or dimethylacetamide; sulfoxides, such as dimethyl sulfoxide; sulfones, such as sulfolane; water; or a mixture of any two or more of these solvents. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from -10° C. to 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvents to be employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from a few minutes to a few days will usually suffice. Where the hydroxy-protecting group is an alkoxycarbonyl group, the protection reaction may be carried out by reacting the starting material with an alkoxycarbonyl halide, such as an alkoxycarbonyl chloride. The reaction is normally and preferably carried out in the presence of an organic base, especially a tertiary amine base, such as trimethylamine, triethylamine or pyridine. The reaction is also normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, tetrahydrofuran or dioxan; aromatic hydrocarbons, such as benzene, toluene or xylene; aliphatic hydrocarbons, such as hexane, heptane or cyclohexane; organic bases, such as pyridine or triethylamine; amides, such as dimethylformamide or dimethylacetamide; sulfoxides, such as dimethyl sulfoxide; and sulfones, such as sulfolane. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° C. to 50° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvents to be employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from a few minutes to a few days will usually suffice. Where the hydroxy-protecting group is a sulfo group, the protection reaction can be carried out by reacting the starting material with a sulfonating agent. This reaction may be carried out according to the procedure described in Japanese Patent Application Kokai No. Sho 62-123186, the disclosure of which is incorporated herein by reference. That is, the starting material is contacted with chlorosulfonic acid in the presence of an organic base, such as pyridine, picoline, lutidine or triethylamine. There is no particular limitation on the molar ratio of the chlorosulfonic acid to the starting material, but the reaction is preferably carried out using from 0.5 to 10 moles of chlorosulfonic acid per mole of the starting material. The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: aromatic hydrocarbons, such as benzene, toluene or xylene; esters, such as ethyl acetate; nitriles, such as acetonitrile; and mixtures of any two or more of these solvents. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 50° C. to 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvent to be employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 minutes to 2 hours will usually suffice. Alternatively the sulfo protecting group may be introduced by esterification of the starting material using sulfuric acid in the presence of a dehydrating agent. Examples of dehydrating agents include: carbodiimides, such as N,N-dicyclohexylcarbodiimide (DCC), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide or a mineral acid salt thereof, such as the hydrochloride; of these, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is preferred. In the esterification, the reaction is preferably carried out using from 1 to 5 moles, more preferably from 1 to 2 moles, of sulfuric acid per mole of the starting material, and from 1 to 10 moles, more preferably from 3 to 6 moles, of the dehydrating agent per mole of the starting material. The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: aromatic hydrocarbons, such as benzene, toluene or xylene; ethers, such as tetrahydrofuran or dioxan; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as methylene chloride or chloroform; nitriles, such as acetonitrile; amides, especially dialkylformamides, such as dimethylformamide or dimethylacetamide; sulfoxides, such as dimethyl sulfoxide; sulfones, such as sulfolane; water; and mixtures of any two or more of these solvents; the amides are preferred. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0° C. to 50° C., more preferably at about room temperature. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and of the solvent to be employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 minutes to 2 days, more preferably from 1 to 3 hours will usually suffice. After completion of the reaction, the desired compounds can be recovered from the reaction mixture by conventional means. For example, one suitable recovery procedure comprises: extracting the compound from the reaction mixture by adding a suitable solvent; and freeing the extracts from the solvents by distillation. The resulting product can then, if desired, be further purified by conventional means, for example recrystallization, reprecipitation or the various chromatography techniques, notably column chromatography, preferably through silica gel. Also, if desired, resolution of the individual isomers can be carried out by conventional means at any appropriate time. The thiazolidine compounds of the present invention exhibited the ability to lower blood-sugar levels in a test system using genetically hyperglycemic animals and exhibited inhibitory activities against aldose reductase in the test system prescribed by Varma et al. [S. D. Varma and H. Kinoshita, Biochem. Pharmac., 25, 2505 (1976)]. The compounds also demonstrated a low toxicity. Accordingly, the compounds of the invention may be used for the treatment and prophylaxis of various diseases and disorders arising from imbalances in the blood sugar level in mammals, especially human beings, for example human hyperlipemia, diabetes and their complications, for example diabetic cataracts, diabetic neurosis and the like. The compounds of the present invention can be administered in various forms, depending on the disorder to be treated and the condition of the patient, as is well known in the art. For example, where the compounds are to be administered orally, they may be formulated as tablets, capsules, granules, powders or syrups; or for parenteral administration, they may be formulated as injections (intravenous, intramuscular or subcutaneous), drop infusion preparations or suppositories. For application by the ophthalmic mucous membrane route, they may be formulated as eyedrops or eye ointments. These formulations can be prepared by conventional means, and, if desired, the active ingredient may be mixed with any conventional additive, such as a vehicle, a binder, a disintegrator, a lubricant, a corrigent, a solubilizing agent, a suspension aid, an emulsifying agent or a coating agent. Although the dosage will vary depending on the symptoms, age and body weight of the patient, the nature and severity of the disorder to be treated or prevented, the route of administration and the form of the drug, for the treatment of hyperlipemia and/or diabetes or complications thereof, a daily dosage of from 5 to 5000 mg of the compound is recommended for an adult human patient, and this may be administered in a single dose or in divided doses. The preparation of the compounds of the present invention is further illustrated by the following non-limiting Examples. The subsequent Experiment illustrates the biological activity of the compounds of the invention. EXAMPLE 1 5-{4-[2-Hydroxy-2-methyl-4-(3,5,6-trimethyl-1,4-benzoquinon-2-yl)butoxy]benzyl}-2,4-dioxothiazolidine 15 ml of an aqueous solution of ferric chloride acidified with hydrochloric acid [a mixture of about 65% by weight of ferric chloride (FeCl 3 .6H 2 O) and about 35% by weight of concentrated hydrochloric acid] were added dropwise, whilst ice-cooling and stirring, to a solution of 6.3 g of 5-[4-(6-hydroxy-2,5,7,8-tetramethylchroman-2-ylmethoxy)benzyl]-2,4-dioxothiazolidine dissolved in 50 ml of acetone, and the resulting mixture was allowed to stand overnight at room temperature. At the end of this time, the reaction mixture was diluted with 500 ml of water and then extracted with ethyl acetate. The extracts were combined, washed with a saturated aqueous solution of sodium chloride and dried over anhydrous sodium sulfate, and the solvent was then removed by distillation under reduced pressure. The resulting residue was then purified by column chromatography through silica gel, using a 5:1 by volume mixture of benzene and ethyl acetate as the eluent, to afford 4.2 g of the title compound as a yellow powder softening at 55°-65° C. Nuclear Magnetic Resonance Spectrum (hexadeuterated acetone) δ ppm: 1.35 (3H, singlet); 1.5-1.85 (2H, multiplet); 1.97 (6H, singlet); 2.05 (3H, singlet); 2.4-2.9 (2H, not determined); 3.11 (1H, doublet of doublets, J=9 & 15 Hz); 3.45 (1H, doublet of doublets, J=3 & 15 Hz); 3.85 (2H, broad); 4.80 (1H, doublet of doublets, J=3 & 9 Hz); 6.90 (2H, doublet, J=9 Hz); 7.25 (2H, doublet, J=9 Hz). EXAMPLE 2 5-{4-[2-Hydroxy-4-hydroxyimino-2-methyl-4-(3,5,6-trimethyl-1,4-benzoquinon-2-yl)butoxy]benzyl}-2,4-dioxothiazolidine The procedure of Example 1 was repeated, but using 2 g of 5-[4-(6-hydroxy-4-hydroxyimino-2,5,7,8-tetramethylchroman-2-ylmethoxy)benzyl]-2,4-dioxothiazolidine, 15 ml of acetone and 5 ml of an aqueous solution of ferric chloride acidified with hydrochloric acid (a mixture of about 65% by weight of FeCl 3 .6H 2 O and about 35% by weight of concentrated hydrochloric acid), to afford 0.74 g of the title compound as a yellow powder softening at 80°-85° C. Nuclear Magnetic Resonance Spectrum (hexadeuterated dimethyl sulfoxide) δ ppm: 1.19 (3H, singlet); 1.79 (3H, broad singlet); 1.84 (3H, broad singlet); 1.97 (3H, singlet); 2.8-3.0 (2H, multiplet); 3.03 (1H, doublet of doublets, J=9 & 14 Hz); 3.25-3.4 (1H, not determined); 3.53 (1H, doublet, J=9 Hz); 3.62 (1H, doublet, J=9 Hz); 4.7-4.85 (1H, broad, disappeared on adding deuterium oxide); 4.85 (1H, doublet of doublets, J=4 & 9 Hz); 6.71 (2H, doublet, J=8.5 Hz); 7.09 (2H, doublet, J=8.5 Hz); 11.41 (1H, singlet, disappeared on adding deuterium oxide); 11.99 (1H, singlet, disappeared on adding deuterium oxide). EXAMPLE 3 5{4-[4-(2,5-Dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutoxy]benzyl}-2,4-dioxothiazolidine 165 mg of sodium borohydride were added, whilst ice-cooling and stirring, to a solution of 1 g of 5-{4-[2-hydroxy-2-methyl-4-(3,5,6-trimethyl-1,4-benzoquinon-2-yl)butoxy]benzyl}-2,4-dioxothiazolidine (prepared as described in Example 1) dissolved in 10 ml of ethanol, and the resulting mixture was stirred at room temperature for 30 minutes. At the end of this time, the reaction mixture was poured into a mixture of 100 ml of ice-water and 0.6 ml of 35% v/v aqueous hydrochloric acid to precipitate white crystals. The crystals were collected by filtration and dried in vacuo over phosphorous pentoxide to afford 0.9 g of the title compound as a yellow powder melting at 84°-88° C. Nuclear Magnetic Resonance Spectrum (hexadeuterated dimethyl sulfoxide) δ ppm: 1.24 (3H, singlet); 1.5-1.65 (2H, multiplet); 2.03 (6H, singlet); 2.05 (3H, singlet); 2.58-2.65 (2H, multiplet); 3.05 (1H, doublet of doublets, J=9 & 14 Hz); 3.25-3.35 (1H, not determined); 3.74 & 3.78 (2H, AB type, J=9 Hz); 4.66 (1H, singlet, disappeared on adding deuterium oxide); 4.86 (1H, doublet of doublets, J=4 & 9 Hz); 6.88 (2H, doublet, J=9 Hz); 7.15 (2H, doublet, J=9 Hz); 7.24 (1H, singlet, disappeared on adding deuterium oxide); 7.26 (1H, singlet, disappeared on adding deuterium oxide); 11.98 (1H, broad singlet, disappeared on adding deuterium oxide). EXAMPLE 4 5-{4-[4-(2,5-Diacetoxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutoxy]benzyl}-2,4-dioxothiazolidine 0.8 g of acetic anhydride was added to a mixture of 0.9 g of 5-{4-[4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutoxy]benzyl}-2,4-dioxothiazolidine (prepared as described in Example 3) and 7 ml of pyridine, and the resulting mixture was allowed to stand at room temperature for 3 days. At the end of this time, the reaction mixture was poured into 50 ml of water and then extracted with ethyl acetate. The extracts were washed, in turn, with 0.1N aqueous hydrochloric acid and with a saturated aqueous solution of sodium chloride, and dried over anhydrous sodium sulfate. The solvent was then removed by distillation under reduced pressure. The resulting residue was then subjected to column chromatography through silica gel, using a 7:3 by volume mixture of benzene and ethyl acetate as the eluent, to afford 0.3 g of the title compound as a white powder softening at 94°-97° C. Nuclear Magnetic Resonance Spectrum (hexadeuterated dimethyl sulfoxide) δ ppm: 1.23 (3H, singlet); 1.4-1.7 (2H, broad); 1.95 (3H, singlet); 1.98 (3H, singlet); 1.99 (3H, singlet); 2.22 (3H, singlet); 2.3-2.7 (2H, not determined); 2.34 (3H, singlet); 3.05 (1H, doublet of doublets, J=9 & 14 Hz); 3.2-3.4 (1H, not determined); 3.72 (1H, doublet, J=9 Hz); 3.79 (1H, doublet, J=9 Hz); 4.72 (1H, singlet); 4.86 (1H, doublet of doublets, J=4 & 9 Hz); 6.91 (2H, doublet, J=9 Hz); 7.15 (2H, doublet, J=9 Hz); 11.98 (1H, broad singlet). EXAMPLE 5 (A) Mono-potassium salt of 5-{4-[4-(2-hydroxy-5-sulfoxy-3,4,6-trimethylphenyl)-2-hvdroxv-2-methylbutoxy[benzyl}-2,4-dioxothiazolidine and (B) mono-potassium salt of 5-{4-[4-(5-hydroxy-2-sulfoxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutoxy}benzyl}-2,4-dioxothiazolidine 0.26 g of chlorosulfonic acid were added to a mixture of 1.0 g of 5-{4-[4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutoxy]benzyl}-2,4-dioxothiazolidine (prepared as described in Example 3), 0.35 g of pyridine and 10 ml of acetonitrile, and the resulting mixture was heated at 80° C. for 3 hours. At the end of this time, the reaction mixture was cooled and the supernatant was removed by decantation. The residual oily material was washed with 10 ml of ethyl acetate. The oil thus obtained was mixed with 5 ml of water and its pH was adjusted to a value of about 6.5 by the addition of an approximately 2N aqueous solution of potassium hydroxide, after which ethyl acetate was added. The ethyl acetate-soluble material was removed, and then the aqueous layer was lyophilized to afford a crude product as a white powder. The crude product was purified by ion-exchange chromatography through Diaion HP-20 (trade mark for a product of Mitsubishi Chemical Industries, Co.) using a 85:15 by volume mixture of water and acetonitrile as the eluent to afford the title compound as a white powder. Mass spectrum (m/e, negative fast atom bombardment method using m-nitrobenzyl alcohol as a matrix; M denotes the molecular weight): (M--H) - =576, (M--K) - =538. The nuclear magnetic resonance spectrum (δ ppm, in hexadeuterated dimethyl sulfoxide) shows that the product thus obtained is an approximately 1:1 mixture of the isomers (A) and (B), based upon the specific signals: 4.80 (1H, quartet), 4.67 (0.5H, singlet) and 4.45 (0.5H, singlet). EXPERIMENT Inhibition of Activitv of Aldose Reductase The inhibition of the activity of aldose reductase is well recognised as a test to indicate the ability of a compound to reduce diabetic complications. Aldose reductase was separated and partially purified from rat lenses by the method of Hyman and Kinoshita [J. Biol. Chem., 240, 877 (1965)]. Enzyme activities were photometrically determined by the method of Varma et al. [Biochem. Pharmac., 25, 2505 (1976)]. The inhibition of aldose reductase activity was determined by employing each test compound in various concentrations. The compound of Example 1 herein showed an IC 50 of 0.82, whilst the known compound, 5-[4-(6-hydroxy-2,5,7,8-tetramethylchroman-2-ylmethoxy)benzyl]-thiazolidine-2,4-dione (which is disclosed in Example 2 of European Patent Publication No. 139 421, and is amongst the closest of the prior art compounds) showed an IC 50 of 2.07, indicating substantially lower activity.

Compounds of formula (I): ##STR1## in which: A is a group of formula (II) or (III): ##STR2## W is methylene, carbonyl or >C═N--OV, where V is hydrogen, sulfo, acyl or alkyl; U is methylene, or W is absent and U is a carbon-carbon double bond between A and --CR 1 (OH)--; R 1 , R 2 , R 3 and R 4 are each hydrogen or alkyl; Y 1 and Y 2 are each hydrogen or a hydroxy-protecting group; and n is 1, 2 or 3 and salts thereof have anti-diabetic activity in mammals. Methods of preparing them are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS This Application is a U.S. national phase application filed under 35 U.S.C. §371 of International Application No. PCT/IN2008/000217, filed Apr. 3, 2008, designating the United States, which claims priority from Indian Patent Application No.: 676/MUM/2007, filed Apr. 4, 2007, which are hereby incorporated herein by reference in their entirety for all purposes. FIELD OF THE INVENTION The present invention relates to the inhibition of metal corrosion in acidic hot hydrocarbons and more particularly to the inhibition of corrosion of iron—containing metals in hot acidic hydrocarbons, especially when the acidity is derived from the presence of naphthenic acid. The invention is also useful for sulphur corrosion inhibition. DISCUSSION OF PRIOR ART It is widely known in the art that the processing of crude oil and its various fractions has led to damage to piping and other associated equipment due to naphthenic acid corrosion. These are corrosive to the equipment used to distill, extract, transport and process the crudes. Generally speaking, naphthenic acid corrosion occurs when the crude being processed has a neutralization number or total acid number (TAN), expressed as the milligrams of potassium hydroxide required to neutralize the acids in a one gram sample, above 0.2. It is also known that naphthenic acid-containing hydrocarbon is at a temperature between about 200° C. and 400° C. (approximately 400° F.-750° F.), and also when fluid velocities are high or liquid impinges on process surfaces e.g. in transfer lines, return bends and restricted flow areas. Corrosion problems in petroleum refining operations associated with naphthenic acid constituents and sulfur compounds in crude oils have been recognized for many years. Such corrosion is particularly severe in atmospheric and vacuum distillation units at temperatures between 400° F. and 790° F. Other factors that contribute to the corrosivity of crudes containing naphthenic acids include the amount of naphthenic acid present, the concentration of sulfur compounds, the velocity and turbulence of the flow stream in the units, and the location in the unit (e.g., liquid/vapor interface). As commonly used, naphthenic acid is a collective term for certain organic acids present in various crude oils. Although there may be present minor amounts of other organic acids, it is understood that the majority of the acids in naphthenic based crude are naphthenic in character, i.e., with a saturated ring structure as follows: The molecular weight of naphthenic acid can extend over a large range. However, the majority of the naphthenic acid from crude oils is found in gas oil and light lubricating oil. When hydrocarbons containing such naphthenic acid contact iron-containing metals, especially at elevated temperatures, severe corrosion problems arise. Naphthenic acid corrosion has plagued the refining industry for many years. This corroding material consists of predominantly monocyclic or bicyclic carboxylic acids with a boiling range between 350° and 650° F. These acids tend to concentrate in the heavier fractions during crude distillation. Thus, locations such as the furnace tubing, transfer lines, fractionating tower internals, feed and reflux sections of columns, heat exchangers, tray bottoms and condensers are primary sites of attack for naphthenic acid. Additionally, when crude stocks high in naphthenic acids are processed, severe corrosion can occur in the carbon steel or ferritic steel furnace tubes and tower bottoms. Recently interest has grown in the control of this type of corrosion in hydrocarbon processing units due to the presence of naphthenic acid in crudes from locations such as China, India, Africa and Europe. Crude oils are hydrocarbon mixtures which have a range of molecular structures and consequent range of physical properties. The physical properties of naphthenic acids which may be contained in the hydrocarbon mixtures also vary with the changes in molecular weight, as well as the source of oil containing the acid. Therefore, characterization and behavior of these acids are not well understood. A well known method used to “quantify” the acid concentration in crude oil has been a KOH titration of the oil. The oil is titrated with KOH, a strong base, to an end point which assures that all acids in the sample have been neutralized. The unit of this titration is mg. of KOH/gram of sample and is referred to as the “Total Acid Number” (TAN) or Neutralization Number. Both terms are used interchangeably in the application. The unit of TAN is commonly used since it is not possible to calculate the acidity of the oil in terms of moles of acid, or any other of the usual analytical terms for acid content. Refiners have used TAN as a general guideline for predicting naphthenic acid corrosion. For example, many refineries blend their crude to a TAN=0.5 assuming that at these concentrations naphthenic acid corrosion will not occur. However, this measure has been unsuccessful in preventing corrosion by naphthenic acid. Naphthenic acid corrosion is very temperature dependent. The generally accepted temperature range for this corrosion is between 205° C. and 400° C. (400° F. and 750° F.). Corrosion attack by these acids below 205° C. has not yet been reported in the published literature. As to the upper boundary, data suggests that corrosion rates reach a maximum at about 600°-700° F. and then begin to diminish. The concentration and velocity of the acid/oil mixture are also important factors which influence naphthenic acid corrosion. This is evidenced by the appearance of the surfaces affected by naphthenic acid corrosion. The manner of corrosion can be deduced from the patterns and color variations in the corroded surfaces. Under some conditions, the metal surface is uniformly thinned. Thinned areas also occur when condensed acid runs down the wall of a vessel. Alternatively, in the presence of naphthenic acid pitting occurs, often in piping or at welds. Usually the metal outside the pit is covered with a heavy, black sulfide film, while the surface of the pit is bright metal or has only, a thin, grey to black film covering it. Moreover, another pattern of corrosion is erosion-corrosion, which has a characteristic pattern of gouges with sharp edges. The surface appears clean, with no visible by-products. The pattern of metal corrosion is indicative of the fluid flow within the system, since increased contact with surfaces allows for a greater amount of corrosion to take place. Therefore, corrosion patterns provide information as to the method of corrosion which has taken place. Also, the more complex the corrosion, i.e., in increasing complexity from uniform to pitting to erosion-corrosion, the lower is the TAN value which triggers the behavior. The information provided by corrosion patterns indicates whether naphthenic acid is the corroding agent, or rather if the process of corrosion occurs as a result of attack by sulfur. Most crude contain hydrogen sulfide, and therefore readily form iron sulfide films on carbon steel. In all cases that have been observed in the laboratory or in the field, metal surfaces have been covered with a film of some sort. In the presence of hydrogen sulfide the film formed is invariably iron sulfide, while in the few cases where tests have been run in sulfur free conditions, the metal is covered with iron oxide, as there is always enough water or oxygen present to produce a thin film on the metal coupons. Tests utilized to determine the extent of corrosion may also serve as indicators of the type of corrosion occurring within a particular hydrocarbon treating unit. Metal coupons can be inserted into the system. As they are corroded, they lose material. This weight loss is recorded in units of mg/cm.sup.2. Thereafter, the corrosion rate can be determined from weight loss measurements. Then the ratio of corrosion rate to corrosion product (mpy/mg/cm.sup.2) is calculated. This is a further indicator of the type of corrosion process which has taken place, for if this ratio is less than 10, it has been found that there is little or no contribution of naphthenic acid to the corrosion process. However, if the ratio exceeds 10, then naphthenic acid is a significant contributor to the corrosion process. Distinguishing between sulfidation attack and corrosion caused by naphthenic acid is important, since different remedies are required depending upon the corroding agent. Usually, retardation of corrosion caused by sulfur compounds at elevated temperatures is effected by increasing the amount of chromium in the alloy which is used in the hydrocarbon treating unit. A range of alloys may, be employed, from 1.25% Cr to 12% Cr, or perhaps even higher. Unfortunately, these show little to no resistance to naphthenic acid. To compensate for the corroding effects of sulfur and naphthenic acid, an austenitic stainless steel which contains at least 2.5% molybdenum, must be utilized. The corrosive problem is known to be aggravated by the elevated temperatures necessary to refine and crack the oil and by the oil's acidity which is caused primarily by high levels of naphthenic acid indigenous to the crudes. Naphthenic acids is corrosive between the range of about 175° C. to 420° C. At the higher temperatures the naphthenic acids are in the vapor phase and at the lower temperatures the corrosion rate is not serious. The corrosivity of naphthenic acids appears to be exceptionally serious in the presence of sulfide compounds, such as hydrogen sulfide, mercaptans, elemental sulfur, sulfides, disulfides, polysulfides and thiophenols. Corrosion due to sulfur compounds becomes significant at temperatures as low as 450° F. The catalytic generation of hydrogen sulfide by thermal decomposition of mercaptans has been identified as a cause of sulfidic corrosion. Sulfur in the crudes, which produces hydrogen sulfide at higher temperatures, also aggravates the problem. The temperature range of primary interest for this type of corrosion is in the range of about 175° C. to about 400° C., especially about 205° C. to about 400° C. Various approaches to controlling naphthenic acid corrosion have included neutralization and/or removal of naphthenic acids from the crude being processed; blending low acid number oils with corrosive high acid number oils to reduce the overall neutralization number; and the use of relatively expensive corrosion-resistant alloys in the construction of the piping and associated equipment. These attempts are generally disadvantageous in that they require additional processing and/or add substantial costs to treatment of the crude oil. Alternatively, various amine and amide based corrosion inhibitors are commercially available, but these are generally ineffective in the high temperature environment of naphthenic acid corrosion. Naphthenic acid corrosion is readily distinguished from conventional fouling problems such as coking and polymer deposition which can occur in ethylene cracking and other hydrocarbon processing reactions using petroleum based feedstocks. Naphthenic acid corrosion produces a characteristic grooving of the metal in contact with the corrosive stream. In contrast, coke deposits generally have corrosive effects due to carburization, erosion and metal dusting. Because these approaches have not been entirely satisfactory, the accepted approach in the industry is to construct the distillation unit, or the portions exposed to naphthenic acid/sulfur corrosion, with the resistant metals such as high quality stainless steel or alloys containing higher amounts of chromium and molybdenum. The installation of corrosion-resistant alloys is capital intensive, as alloys such as 304 and 316 stainless steels are several times the cost of carbon steel. However, in units not so constructed there is a need to provide inhibition treatment against this type of corrosion. The prior art corrosion inhibitors for naphthenic acid environments include nitrogen-based filming corrosion inhibitors. However, these corrosion inhibitors are relatively ineffective in the high temperature environment of naphthenic acid oils. While various corrosion inhibitors are known in various arts, the efficacy and usefulness of any particular corrosion inhibitor is dependent on the particular circumstances in which it is applied. Thus, efficacy or usefulness under one set of circumstances often does not imply the same for another set of circumstances. As a result, a large number of corrosion inhibitors have been developed and are in use for application to various systems depending on the medium treated, the type of surface that is susceptible to the corrosion, the type of corrosion encountered, and the conditions to which the medium is exposed. For example, U.S. Pat. No. 3,909,447 describes certain corrosion inhibitors as useful against corrosion in relatively low temperature oxygenated aqueous systems such as water floods, cooling towers, drilling muds, air drilling and auto radiator systems. That patent also notes that many corrosion inhibitors capable of performing in non-aqueous systems and/or non-oxygenated systems perform poorly in aqueous and/or oxygenated systems. The reverse is true as well. The mere fact that an inhibitor that has shown efficacy in oxygenated aqueous systems does not suggest that it would show efficacy in a hydrocarbon. Moreover, the mere fact that an inhibitor has been efficacious at relatively low temperatures does not indicate that it would be efficacious at elevated temperatures. In fact, it is common for inhibitors that are very effective at relatively low temperatures to become ineffective at temperatures such as the 175° C. to 400° C. encountered in oil refining. At such temperatures, corrosion is notoriously troublesome and difficult to alleviate. Thus, U.S. Pat. No. 3,909,447 contains no teaching or suggestion that it would be effective in non-aqueous systems such as hydrocarbon fluids, especially hot hydrocarbon fluids. Nor is there any indication in U.S. Pat. No. 3,909,447 that the compounds disclosed therein would be effective against naphthenic acid corrosion under such conditions. Atmospheric and vacuum distillation systems are subject to naphthenic acid corrosion when processing certain crude oils. Currently used treatments are thermally reactive at use temperatures. In the case of phosphorus-based inhibitors, this is thought to lead to a metal phosphate surface film. The film is more resistant to naphthenic acid corrosion than the base steel. These inhibitors are relatively volatile and exhibit fairly narrow distillation ranges. They are fed into a column above or below the point of corrosion depending on the temperature range. Polysulfide inhibitors decompose into complex mixtures of higher and lower polysulfides and, perhaps, elemental sulfur and mercaptans. Thus, the volatility and protection offered is not predictable. The problems caused by naphthenic acid corrosion in refineries and the prior art solutions to that problem have been described at length in the literature, the following of which are representative: U.S. Pat. No. 3,531,394 to Koszman described the use of phosphorus and/or bismuth compounds in the cracking zone of petroleum steam furnaces to inhibit coke formation on the furnace tube walls. U.S. Pat. No. 4,024,049 to Shell et al discloses compounds substantially as described and claimed herein for use as refinery antifoulants. While effective as antifoulant materials, materials of this type have not heretofore been used as corrosion inhibitors in the manner set forth herein. While this reference teaches the addition of thiophosphate esters such as those used in the subject invention to the incoming feed, due to the non-volatile nature of the ester materials they do not distill into the column to protect the column, the pump around piping, or further process steps. I have found that by injecting the thiophosphate esters as taught herein, surprising activity is obtained in preventing the occurrence of naphthenic acid corrosion in distillation columns, pump around piping, and associated equipment. U.S. Pat. No. 4,105,540 to Weinland describes phosphorus containing compounds as antifoulant additives in ethylene cracking furnaces. The phosphorus compounds employed are mono- and di-ester phosphate and phosphite compounds having at least one hydrogen moiety complexed with an amine. U.S. Pat. No. 4,443,609 discloses certain tetrahydrothiazole phosphonic acids and esters as being useful as acid corrosion inhibitors. Such inhibitors can be prepared by reacting certain 2, 5-dihydrothiazoles with a dialkyl phosphite. While these tetrahydrothiazole phosphonic acids or esters have good corrosion and inhibition properties, they tend to break down during high temperature applications thereof with possible emission of obnoxious and toxic substances. It is also known that phosphorus-containing compounds impair the function of various catalysts used to treat crude oil, e.g., in fixed-bed hydrotreaters and hydrocracking units. Crude oil processors are often in a quandary since if the phosphite stabilizer is not used, then iron can accumulate in the hydrocarbon up to 10 to 20 ppm and impair the catalyst. Although nonphosphorus-containing inhibitors are commercially available, they are generally less effective than the phosphorus-containing compounds. U.S. Pat. No. 4,542,253 to Kaplan et al, described an improved method of reducing fouling and corrosion in ethylene cracking furnaces using petroleum feedstocks including at least 10 ppm of a water soluble mine complexed phosphate, phosphite, thiophosphate or thiophosphite ester compound, wherein the amine has a partition coefficient greater than 1.0 (equal solubility in both aqueous and hydrocarbon solvents). U.S. Pat. No. 4,842,716 to Kaplan et al describes an improved method for reducing fouling and corrosion at least 10 ppm of a combination of a phosphorus antifoulant compound and a filming inhibitor. The phosphorus compound is a phosphate, phosphite, thiophosphate or thiophosphite ester compound. The filming inhibitor is an imidazoline compound. U.S. Pat. No. 4,941,994 Zetmeisl et al discloses a naphthenic acid corrosion inhibitor comprising a dialkyl or trialkylphosphite in combination with an optional thiazoline. A significant advancement in phosphorus-containing naphthenic acid corrosion inhibitors was reported in U.S. Pat. No. 4,941,994. Therein it is disclosed that metal corrosion in hot acidic liquid hydrocarbons is inhibited by the presence of a corrosion inhibiting amount of a dialkyl and/or trialkyl phosphite with an optional thiazoline. While the method described in U.S. Pat. No. 4,941,994 provides significant improvements over the prior art techniques, nevertheless, there is always a desire to enhance the ability of corrosion inhibitors while reducing the amount of phosphorus-containing compounds which may impair the function of various catalysts used to treat crude oil, as well as a desire for such inhibitors that may be produced from lower cost or more available starting materials. Another approach to the prevention of naphthenic acid corrosion is the use of a chemical agent to form a barrier between the crude and the equipment of the hydrocarbon processing unit. This barrier or film prevents corrosive agents from reaching the metal surface, and is generally a hydrophobic material. Gustaysen et al. NACE Corrosion 89 meeting, paper no. 449, Apr. 17-21, 1989 details the requirements for a good filming agent. U.S. Pat. No. 5,252,254 discloses one such film forming agent, sulfonated alkyl-substituted phenol, and effective against naphthenic acid corrosion. U.S. Pat. No. 5,182,013 issued to Petersen et al. on Jan. 26, 1993 describes another method of inhibiting naphthenic acid corrosion of crude oil, comprising introducing into the oil an effective amount of an organic polysulfide. The disclosure of U.S. Pat. No. 5,182,013 is incorporated herein by reference. This is another example of a corrosion-inhibiting sulfur species. Sulfidation as a source of corrosion was detailed above. Though the process is not well understood, it has been determined that while sulfur can be an effective anti-corrosive agent in small quantities, at sufficiently high concentrations, it becomes a corrosion agent. Phosphorus can form an effective barrier against corrosion without sulfur, but the addition of sulfiding agents to the process stream containing phosphorus yields a film composed of both sulfides and phosphates. This results in improved performance as well as a decreased phosphorus requirement. This invention pertains to the deliberate addition of sulfiding agents to the process stream when phosphorus-based materials are used for corrosion control to accentuate this interaction. U.S. Pat. No. 5,314,643 to Edmondson et al., describes a process for inhibition of corrosion caused by naphthenic acid and sulphur compounds during the elevated temperature processing of crude oil by use of a corrosion inhibitor consisting of a combination of trialkylphosphate and an alkaline earth metal phosphonate-phenate sulphide, functioning effectively as an inhibitor on the internal metallic surfaces of the equipment used in crude oil refining operations. Organic polysulfides (Babaian-Kibala, U.S. Pat. No. 5,552,085), organic phosphites (Zetlmeisl, U.S. Pat. No. 4,941,994), and phosphate/phosphite esters (Babaian-Kibala, U.S. Pat. No. 5,630,964), have been claimed to be effective in hydrocarbon-rich phase against naphthenic acid corrosion. However, their high oil solubility incurs the risk of distillate side stream contamination by phosphorus. Phosphoric acid has been used primarily in aqueous phase for the formation of a phosphate/iron complex film on steel surfaces for corrosion inhibition or other applications (Coslett, British patent 8,667, U.S. Pat. Nos. 3,132,975, 3,460,989 and 1,872,091). Phosphoric acid use in high temperature non-aqueous environments (petroleum) has also been reported for purposes of fouling mitigation (U.S. Pat. No. 3,145,886). There remains a continuing need to develop additional options for mitigating the corrosivity of acidic crudes at lower cost. This is especially true at times of low refining margins and a high availability of corrosive crudes from sources such as Europe, China, or Africa, and India. The present invention addresses this need. OBJECTS AND ADVANTAGES OF PRESENT INVENTION Accordingly, the objects and advantages of the present invention are described below. An object of present invention is to provide a chemical composition which will provide very effective high temperature naphthenic acid corrosion inhibition as well as sulphur corrosion inhibition. Another object of the present invention is to provide a corrosion inhibiting composition, which is very stable even at high temperature. Yet another object of the present invention is to provide a corrosion inhibiting composition, having very low acid value. SUMMARY OF INVENTION The present invention relates to the field of processing hydrocarbons which causes corrosion in the metal surfaces of processing units. The invention addresses the technical problem of high temperature naphthenic acid corrosion and sulphur corrosion and provides a solution to inhibit these types of corrosion. The three combination compositions are formed by three mixtures separately, with one mixture obtained by mixing compound A, which is obtained by reacting high reactive polyisobutylene (HRPIB) with phosphorous pentasulphide in presence of catalytic amount of sulphur with compound B such as trialkyl phosphate and second mixture obtained by mixing compound A with compound C such as phosphite like di-isodecyl phenyl phosphite, and third mixture obtained by mixing compound A with compound D such as a phosphonate, wherein each of these three mixtures independently provide high corrosion inhibition efficiency in case of high temperature naphthenic acid corrosion inhibition and sulphur corrosion inhibition. The invention is useful in all hydrocarbon processing units, such as, refineries, distillation columns and other petrochemical industries. DESCRIPTION OF THE INVENTION It has been surprisingly discovered by the inventor of the present invention, that a combination of organophosphorus sulphur compound and any of other phosphorus compounds such as, phosphates, phosphites and phosphonates, is very efficiently functioning in controlling naphthenic acid corrosion, providing a synergetic effect of combination of Phosphorus compounds. The organophosphorus sulphur compound is made from reaction of hydrocarbon R 1 such as olefins with, phosphorus pentasulphide, in presence of sulphur powder. Amongst the other Phosphorus compounds tributylphosphate and di-isodecyl phenyl phosphite are the preferred ones. The preferred olefins have double bonds, wherein double bond is present internally or terminally. The details about such hydrocarbon R 1 are given below: As previously mentioned, the term “hydrocarbon” as used herein means any one of an alkyl group, an alkenyl group, an alkynyl group, which groups may be linear, branched or cyclic, or an aryl group. The term hydrocarbon also includes those groups but wherein they have been optionally substituted. If the hydrocarbon is a branched structure having substituent(s) thereon, then the substitution may be on either the hydrocarbon backbone or on the branch; alternatively the substitutions may be on the hydrocarbon backbone and on the branch. Preferably R 1 is an optionally substituted alkyl or alkenyl group. In one aspect R 1 is an optionally substituted alkyl group. In another aspect, R 1 is an optionally substituted alkenyl group. The term “alkenyl” refers to a branched or straight chain hydrocarbon, which can comprise one or more carbon-carbon double bonds. Exemplary alkenyl groups include propylenyl, butenyl, isobutenyl, pentenyl, 2,2-methylbutenyl, 3-methylbutenyl, hexanyl, heptenyl, octenyl, and polymers thereof. In one aspect R 1 is an optionally substituted branched alkyl or alkenyl group. Preferably, R 1 is a polyisobutenyl (PIB) group. Conventional PIBs and so-called “high-reactivity” PIBs (see for example EP-B-0565285) are suitable for use in this invention. High reactivity in this context is defined as a PIB wherein at least 50%, preferably 70% or more, of the terminal olefinic double bonds are of the vinylidene type, for example the GLISSOPAL compounds available from BASF. In one aspect R 1 has between 10 and 1000 carbon atoms, preferably between 4 and 200 carbon atoms. In one aspect, R 1 has a molecular weight of from 200 to 10000, preferably from 200 to 1300. The trialkylphosphate such as tributyl phosphate will contain an alkyl moiety of C 1 -C 12 such that those compounds contemplated as having the desired efficacy and within the disclosure of the present invention include trimethylphosphate, triethylphosphate, tripropylphosphate, tributylphosphate and tripentylphosphate. Due to its easy commercial availability, tributylphosphate may be considered the preferred compound. The most effective amount of the corrosion inhibitor to be used in accordance with the present invention can vary depending on the local operating conditions and the particular hydrocarbon being processed. Thus, the temperature and other characteristics of the acid corrosion system can have a bearing on the amount of inhibitor or mixture of inhibitors to be used. Generally, where the operating temperatures and/or the acid concentrations are higher, a proportionately higher amount of the corrosion inhibitor will be required. It has been found that the concentration of the corrosion inhibitors or mixture of inhibitors added to the crude oil may range from about 1 ppm to 5000 ppm. It has also been found that it is preferred to add the inhibitors at a relatively high initial dosage rate of 2000-3000 ppm and to maintain this level for a relatively short period of time until the presence of the inhibitor induces the build-up of a corrosion protective coating on the metal surfaces. Once the protective surface is established, the dosage rate needed to maintain the protection may be reduced to a normal operational range of about 100-1500 ppm without substantial sacrifice of protection. The inventor of the present invention has carried out extensive experimentation to verify the effectiveness of corrosion—inhibition in case naphthenic acid corrosion, by experimenting with different proportions of compound A, that is, polyisobutylene plus phosphorus pentasulphide plus sulphur powder and compound B, that is, tributyl phosphate in the abovementioned combination of these compounds. Experiments were also preformed by using compound A alone and compound B alone separately. The inventor of the present invention has also carried out extensive experimentation to verify the effectiveness of corrosion—inhibition in case of naphthenic acid corrosion, by experimenting with different proportions of compound A, that is, polyisobutylene plus phosphorus pentasulphide plus sulphur powder and compound C, that is, di-isodecyl phenyl phosphite in the abovementioned combination of these compounds. Experiments were also preformed by using compound A alone and compound B alone and compound C alone, separately. The reacted compound “A” is obtained by reaction of olefins with P 2 S 5 (Phosphorus pentasulphide) in presence of sulphur powder. The preferred olefins have double bonds, wherein double bond is present internally or terminally. The example of internally double bonded olefins include beta-olefins. The example of terminally double bonded olefins include alpha-olefins. These olefins have 5 to 30 carbon atoms. These olefins are alternatively, polymeric olefins such as high reactive polyisobutylene containing greater than 70% of vinyledene double bond, and normal polyisobutylene which contains Vinyl, vinyledene, and such other groups of chemicals. The ratio of P 2 S 5 to Olefin is preferably 0.05 to 2 mole of P 2 S 5 to 1 mole of Olefins. The Sulphur powder is present in catalytic quantity, that is, sulphur powder is 0.5% to 5% of Olefin by weight. The most preferred embodiment of the present invention is described below: A weighed quantity of HRPIB (High Reactive Polyisobutylene), Phosphorus pentasulphide and sulphur powder are charged into a clean four-necked round bottom flask, equipped with nitrogen inlet, stirrer and thermometer, thereby forming a reaction mixture. This reaction mixture is stirred and heated to temperature of 160° C. under nitrogen gas purging. At this temperature of 160° C., the reaction leads to evolution of hydrogen sulphide gas (H 2 S). The temperature of the reaction mixture is now maintained between 160° C. to 180° C., for a period of 1 hour to 2 hours. Then the temperature of the mixture is raised to 220° C. The reaction mixture is then maintained at this temperature of 220° C. for 6 hours. This reaction mixture is stirred and heated to temperature of 160° C. under nitrogen gas purging. At this temperature of 160° C., the reaction leads to evolution of hydrogen sulphide gas (H 2 S). The temperature of the reaction mixture is now maintained between 160° C. to 180° C., for a period of 1 hour to 2 hours. Then the temperature of the mixture is raised to 220° C. The reaction mixture is then maintained at this temperature of 220° C. for 6 hours. The present invention is directed to a method for inhibiting corrosion on the metal surfaces of the processing units which process hydrocarbons such as crude oil and its fractions containing naphthenic acid. The invention is explained in details in its simplest form wherein the following method steps are carried out, when it is used to process crude oil in process units such as distillation unit. Similar steps can be used in different processing units such as, pump around piping, heat exchangers and such other processing units. These method steps are explained below: a) heating the hydrocarbon containing naphthenic acid to vaporize a portion of the hydrocarbon; b) allowing the hydrocarbon vapors to rise in a distillation column; c) condensing a portion of the hydrocarbon vapours passing through the distillation column to produce a distillate; d) adding to the distillate, from 1 to 5000 ppm of a combination compound (A+B) or combination compound (A+C) of instant invention; e) allowing the distillate containing combination compound (A+B) or combination compound (A+C) to contact substantially the entire metal surfaces of the distillation unit to form protective film on such surface, whereby such surface is inhibited against corrosion. It is advantageous to treat distillation column, trays, pump around piping and related equipment to prevent naphthenic acid corrosion, when condensed vapours from distilled hydrocarbon fluids contact metallic equipment at temperatures greater than 200° C., and preferably 400° C. The combination compound (A+B) or combination compound (A+C) as additive is generally added to the condensed distillate and the condensed distillate is allowed to contact the metallic surfaces of the distillation column, packing, trays, pump around piping and related equipment as the condensed distillate passes down the column and into the distillation vessel. The distillate may also be collected as product. The corrosion inhibitors of the instant invention remain in the resultant collected product. In commercial practice, the additives of this invention may be added to a distillate return to control corrosion in a draw tray and in the column packing while a second injection may be added to a spray oil return immediately below the draw trays to protect the tower packing and trays below the distillate draw tray. It is not so critical where the additive of the invention is added as long as it is added to distillate that is later returned to the distillation vessel, or which contact the metal interior surfaces of the distillation column, trays, pump around piping and related equipments. The method of using the polyisobutylene phosphorus sulphur compound of the present invention for achieving inhibition of high temperature naphthenic acid corrosion is explained below with the help of examples 1 and 2. Example 3 shows use of compound B. Example 4 shows use of combination compound (A+B). Example 5 shows use of compound C. Example 6 shows use of combination compound (A+C). The compound B of the combination compound (A+B) of the present invention is easily obtained commercially. The compound C of the combination compound (A+C) of the present invention is easily obtained commercially. EXAMPLE 1 The weighed quantities of 68.16 gm of commercially available HRPIB (High Reactive Polyisobutylene with molecular weight 950 approximately), 30.31 gm of Phosphorus Pentasulphide and 1.51 gm of Sulphur Powder are charged into a clean four necked round bottom flask, equipped with N 2 inlet, stirrer and thermometer, thereby forming a reaction mixture. This gives 1:1 mole ratio of Phosphorus Pentasulphide to Olefin. The reaction mixture was stirred and heated to 160° C. temperature under nitrogen gas purging. The purging of N 2 gas led to removal of hydrogen sulphide gas, which was generated during the reaction. The temperature of the reaction mixture was maintained between 160° C. to 180° C., for a period of 1 hour to 2 hours. Then the temperature of the mixture was raised to 220° C. and the mixture was maintained at this temperature for 6 to 10 hours. The resultant reaction mass was then cooled to 100° C. when nitrogen gas was purged into it, to drive out the hydrogen sulphide gas present therein. The resulting polyisobutylene Phosphorus sulphur compound was used as a high temperature naphthenic acid corrosion inhibitor, as well as, sulphur corrosion inhibitor. This compound was used neat or diluted in appropriate solvent such as xylene, toluene, and aromatic solvent as well as any other appropriate solvent to achieve inhibition of high temperature naphthenic acid corrosion as well as sulphur corrosion. The above mentioned synthesis is carried out for different molar ratios of 1:1, 1:0.5 and 1:0.25 of HRPIB to Phosphorus Pentasulphide. A similar synthesis was carried out by using normal polyisobutylene instead of HRPIB, with molar ratio of 1:0.35. EXAMPLE 2 High Temperature Naphthenic Acid Corrosion Test In this example, various amounts of a 50% formulation of the composition prepared in accordance, with Example 1, were tested for corrosion inhibition efficiency on steel coupons in hot oil containing naphthenic acid. A weight loss coupon, immersion test was used to evaluate the invention compound for its effectiveness in inhibition of naphthenic acid corrosion at 290° C. temperature. Different dosage such as 300, 400 and 600 ppm of invention compound were used, as 50% active solution. A corrosion inhibition test on steel coupon was conducted without using any additive. This test provided a blank test reading. The reaction apparatus consisted of a one-litre four necked round bottom flask equipped with water condenser, N 2 purger tube, thermometer pocket with thermometer and stirrer rod. 600 gm (about 750 ml) paraffin hydrocarbon oil (D-130) was taken in the flask. N 2 gas purging was started with flow rate of 100 cc/minute and the temperature was raised to 100° C., which temperature was maintained for 30 minutes. A compound of example 1 comprising Polyisobutylene and Phosphorus Pentasulphide with sulphur powder was added to the reaction mixture. The reaction mixture was stirred for 15 minutes at 100° C. temperature. After removing the stirrer, the temperature of the reaction mixture was raised to 290° C. A pre-weighed weight-loss carbon steel coupon CS 1010 with dimensions 76 mm×13 mm×1.6 mm was immersed. After maintaining this condition for 1 hour to 1.5 hours, 31 gm of naphthenic acid (commercial grade with acid value of 230 mg/KOH) was added to the reaction mixture. A sample of one gm weight of reaction mixture was collected for determination of acid value, which was found to be approximately 11.7. This condition was maintained for four hours. After this procedure, the metal coupon was removed, excess oil was rinsed away, and the excess corrosion product was removed from the metal surface. Then the metal coupon was weighed and the corrosion rate was calculated in mils per year. Calculation of Corrosion Inhibition Efficiency. The method used in calculating Corrosion Inhibition Efficiency is given below. In this calculation, corrosion inhibition efficiency provided by additive compound is calculated by comparing weight loss due to additive with weight loss of blank coupon (without any additive). Corrosion ⁢ ⁢ Inhibition ⁢ ⁢ Efficiency = ( Weight ⁢ ⁢ loss ⁢ ⁢ for ⁢ ⁢ blank ⁢ ⁢ without ⁢ ⁢ additive ) - ( weight ⁢ ⁢ loss ⁢ ⁢ with ⁢ ⁢ additive ) ( weight ⁢ ⁢ loss ⁢ ⁢ for ⁢ ⁢ blank ⁢ ⁢ without ⁢ ⁢ additive ) × 100 The calculated magnitudes are entered in the Tables in appropriate columns. The results of the experiments are presented in Table I and II. The test results of the experiments conducted by using normal polyisobutylene are given in Table III. The corrosion rate in MPY (mils per year) is calculated by the formula, M ⁢ ⁢ P ⁢ ⁢ Y = 534 × Weight ⁢ ⁢ loss ⁢ ⁢ in ⁢ ⁢ mg ( Density ⁢ ⁢ in ⁢ ⁢ gm ⁢ / ⁢ cc ) × ( Area ⁢ ⁢ in ⁢ ⁢ in 2 ) × ( Time ⁢ ⁢ of ⁢ ⁢ test ⁢ ⁢ in ⁢ ⁢ hours ) EXAMPLE 3 Experiments were carried out by the inventor of the present invention, to test the effectiveness of a commercially available phosphorus compound B, such as tributyl phosphate, in inhibition of naphthenic acid corrosion. Different dosages of tributyl phosphate, such as 75, 90 and 100 ppm were used in the experiments. The result of some of these experiments are presented in Table 5. EXAMPLE 4 Experiments were carried out by the inventor of the present invention, to test the synergetic effectiveness of a combination of the compounds A and B, where compound A represents high reactive polyisobutylene plus Phosphorus pentasulphide plus sulphur powder and compound B represents tributyl phosphate (compound B is used as available commercially). Different total dosages of inhibitor combination compound's combination such as 300 ppm and 400 ppm were used in the experimentation. Similarly, different proportions of compound A and compound B, were used in these experiments. These different percentage proportions of A:B were 67:33, 70:30, 75:25, and 81:19. The result of these experiments are presented in Tables 6 to 8. EXAMPLE 5 By using the method steps similar to that of example 2, the experiments were carried out by the inventor of the present invention, to test the effectiveness of another commercially available Phosphorus compound C, such as Di-isodecyl Phenyl Phosphite, in inhibition of naphthenic acid corrosion. Different active dosages of Di-isodecyl Phenyl Phosphite, such as 75, 90, 120 and 150 ppm were used in the experiments. The results of these experiments are presented in Table 9. EXAMPLE 6 By using the method steps similar to that of example 5, the experiments were carried out by the inventor of the present invention, to test synergetic effectiveness of a combination of the compounds A and C, in inhibition of naphthenic acid corrosion, where compound A represents high reactive polyisobutylene plus phosphorus pentasulphide plus catalytic amount of sulphur powder and compound C represents Di-isodecyl Phenyl Phosphite, (Compound C is used as available commercially). Different total active dosages of inhibitor combination compound's combination such as 195, 200, 210, 250, 300 ppm were used in the experimentation. Similarly these total active dosages included different proportions of active compounds A and C. These different proportions of A:C included 105:90, 90:120, 100:100, 140:60, 110:90, 130:120 and 180:120 the results of these experiments are presented in Table 10. TABLE 1 CORROSION INHIBITION TEST (with molar ratio of Polyisobutylene to Phosphorus Pentasulphide = 1:1) (EXAMPLE - 2) Corrosion Effective Weight Inhibition Inhibitor Dosage in Dosage in Loss in Corrosion efficiency Expt. No. Compound ppm ppm mg Rate in MPY in % 1 (Only blank) — — 89.5 529.89 0 2 Composition as 200 100 63.3 371.23 29.27 per Example 1 3 Composition as 300 150 39.6 232.24 55.75 per Example 1 4 Composition as 400 200 15.2 89.114 83.02 per Example 1 5 Composition as 600 300 3.8 12.31 95.75 per Example 1 6 Composition as 650 325 0.3 1.5 99.67 per Example 1 TABLE 2 CORROSION INHIBITION TEST (with molar ratio of Polyisobutylene to Phosphorus Pentasulphide = 1:0.5) (EXAMPLE - 2) Corrosion Dosage Effective Weight Corrosion Inhibition Inhibitor in Dosage Loss in Rate in Efficiency Experiment No. Compound ppm in ppm mg MPY in % 15 — — — 87.7 439 0 (Only blank) 7 Composition 500 250 21.5 107.62 75.48 as per Example 1 TABLE 3 CORROSION INHIBITION TEST (with molar ratio of Polyisobutylene to Phosphorus Pentasulphide = 1:0.25) (EXAMPLE - 2) Corrosion Dosage Effective Weight Corrosion Inhibition Inhibitor in Dosage Loss in Rate in efficiency Experiment No. Compound ppm in ppm mg MPY in % 15 — — — 87.7 439 0 (Only blank) 8 Composition 500 250 50.6 253.3 42.3 as per Example 1 9 Composition 1000 500 14.2 71.08 83.81 as per Example 1 10 Composition 1500 750 2.0 10.1 97.72 as per Example 1 TABLE 4 CORROSION INHIBITION TEST (with molar ratio of Normal Polyisobutylene to Phosphorus Pentasulphide = 1:0.35) Corro- Corrosion Dosage Effective Weight sion Inhibition Expt. Inhibitor in Dosage Loss in Rate in efficiency No. Compound ppm in ppm mg MPY in % 15 — — — 87.7 439 0 (Only blank) 11 Composition 600 300 40 200.21 54.39 as per Example 1 TABLE 5 CORROSION INHIBITION TEST (Inhibitor compound B = Tributyl Phosphate) Corrosion Weight Inhibition Experiment Inhibitor Dosage Loss in Corrosion efficiency No. Compound in ppm mg Rate MPY in % 1 — — 89.5 529.89 0 (Only blank) 12 Tributyl 75 55.5 325.49 37.99 Phosphate (as commercially available) without any solvent 13 Compound as 90 21.95 128.73 75.48 per Experiment No 12 14 Compound as 100 14.35 84.16 83.97 per Experiment No 12 TABLE 6 CORROSION INHIBITION TEST (Inhibitor compound = A + B) Dosage in (ppm) Corrosion Total Weight Corrosion Inhibition Expt. Inhibitor Dosage loss Rate in efficiency No. M.R compound Compound A Compound B A + B (mg) (MPY) (%) 15 — (Blank) — — — 87.70 439 0 16 1:1 A + B 120 80 200 0 10 100 17 1:1 A + B 150 75 225 2.2 11.01 97.49 18 1:1 A + B 180 60 240 0.7 3.5 99.20 Compound A = 50% of Polyisobutylene plus Phosphorus Pentasulphide + Catalytic amount of Sulphur Powder (as per example 1) and 50% solvent Compound B = Tributyl Phosphate (as commercially available) without any solvent. M.R. = Molar Ratio of Polyisobutylene to Phosphorus Pentasulphide TABLE 7 CORROSION INHIBITION TEST (Inhibitor compound = A + B) Dosage in (ppm) Corrosion Total Weight Corrosion Inhibition Expt. Inhibitor Dosage loss Rate in efficiency No. M.R. compound Compound A Compound B A + B (mg) (MPY) (%) 1 — (Only blank) — — — 89.5 529.89 0 19 1:1 A + B 200 100 300 2.73 16.01 96.95 20 1:1 A + B 210 90 300 2.90 17.00 96.76 21 1:1 A + B 225 75 300 5.30 31.08 94.08 22 1:1 A + B 325 75 400 4.70 27.56 94.75 Compound A = 50% of Polyisobutylene plus Phosphorus Pentasulphide + Catalytic amount of Sulphur Powder (as per example 1) and 50% solvent Compound B = Tributyl Phosphate (as commercially available) without any solvent. M.R. = Molar Ratio of Polyisobutylene to Phosphorus Pentasulphide TABLE 8 CORROSION INHIBITION TEST (Inhibitor compound = A + B) Corrosion Dosage in (ppm) Weight Corrosion. Inhibition Experiment Inhibitor Total Dosage loss Rate in efficiency No. M.R. comp. Comp. A Comp. B A + B (mg) (MPY) (%) 15 — (Only — — — 87.7 439 0 blank) 23 1:0.5 A + B 300 75 375 1.8 9.01 97.95 24 1:0.5 A + B 330 60 390 5.2 26.03 94.07 25 1:0.5 A + B 255 45 300 39.4 197.21 55.07 Compound A = 50% of Polyisobutylene plus Phosphorus Pentasulphide + Catalytic amount of Sulphur Powder (as per example 1) and 50% solvent Compound B = Tributyl Phosphate (as commercially available) without any solvent. M.R. = Molar Ratio of Polyisobutylene to Phosphorus Pentasulphide TABLE 9 CORROSION INHIBITION TEST (Inhibitor compound C = Di-isodecyl Phenyl Phosphite as commercially available without any solvent) Corrosion Exper- Dosage Weight Corrosion Inhibition iment Inhibitor in Loss in Rate in efficiency No. Compound ppm mg MPY in % 15 (Only blank) — 87.70 439 0 26 Di-isodecyl Phenyl 75 73.90 369.90 15.74 Phosphite without any solvent 27 Compound as per 90 58.5 292.81 33.30 Experiment No 26 28 Compound as per 120 21.0 105.11 76.05 Experiment No 26 29 Compound as per 150 1.60 8.01 98.18 Experiment No 26 TABLE 10 CORROSION INHIBITION TEST (Inhibitor compound = A + C) Corrosion Dosage in (ppm) Weight Corrosion Inhibition Expt. Inhibitor Total Dosage loss Rate in efficiency No. M.R. compound Comp. A Comp. C A + C (mg) (MPY) (%) 15 — (Only — — — 87.7 439 0 blank) 30 1:1 A + C 210 90 300 4.9 24.53 94.41 31 1:1 A + C 180 120 300 0.7 3.5 99.20 32 1:1 A + C 200 100 300 0.3 1.5 99.66 33 1:1 A + C 280 60 340 0.4 2.0 99.54 34 1:1 A + C 220 90 310 0.1 0.5 99.89 35   1:0.5 A + C 260 120 380 1.5 7.51 98.29 36   1:0.5 A + C 360 120 480 3.4 17.02 96.12 Compound A = 50% of Polyisobutylene plus Phosphorus Pentasulphide + Catalytic amount of Sulphur Powder (as per example 1) and 50% solvent Compound C = Di-isodecyl Phenyl Phosphite as commercially available without any solvent TABLE 11 CORROSION INHIBITION TEST (Inhibitor compound = A + B) Corrosion Dosage in (ppm) Weight Corrosion. Inhibition Expt. Inhibitor Total Dosage loss Rate in efficiency No. M.R. comp. Comp. A Comp. B A + B (mg) (MPY) (%) 15 — (Only — — — 87.7 439 0 blank) 37 1:0.35 A + B 320 90 410 1.3 6.5 98.52 Compound A = 50% of Normal Polyisobutylene plus Phosphorus Pentasulphide + Catalytic amount of Sulphur Powder (as per example 1) and 50% solvent Compound B = Tributyl Phosphate (as commercially available) without any solvent. M.R. = Molar Ratio of Polyisobutylene to Phosphorus Pentasulphide TABLE 12 CORROSION INHIBITION TEST (Inhibitor compound = A + C) Corrosion Dosage in (ppm) Weight Corrosion Inhibition Expt. Inhibitor Total Dosage loss Rate in efficiency No. M.R. compound Comp. A Comp. C A + C (mg) (MPY) (%) 15 — (Only blank) — — — 87.7 439 0 38 1:0.35 A + C 360 120 480 24.2 121 72.41 Compound A = 50% of Normal Polyisobutylene plus Phosphorus Pentasulphide + Catalytic amount of Sulphur Powder (as per example 1) and 50% solvent Compound C = Di-isodecyl Phenyl Phosphite as commercially available without any solvent Discussion of the Results Presented in Tables The detailed discussion given below with respect to the results presented in Tables 1 to 12 for the experiments described in Examples 1 to 6 explains the effectiveness of the additive inhibitor compounds of present invention in high temperature naphthenic acid corrosion inhibition or sulphur corrosion inhibition. The additive inhibitor compound of the present invention, which is very effective in inhibition of high temperature naphthenic acid corrosion, comprises a mixture of a compound A with either of the two compounds B and C, wherein, A=50% of reaction product of Polyisobutylene plus Phosphorus Pentasulphide+Catalytic amount of Sulphur Powder (as per example 1) and 50% solvent. B=Tributyl Phosphate, (as commercially available), without any solvent. C=Di-isodecyl Phenyl Phosphite, (as commercially available), without any solvent. The results presented in the Tables 1 to 12, show separately the effectiveness of each of the three compounds A, B, and C and also show separately the effectiveness of the each of the two mixture (A+B) and (A+C). The detailed discussion given below, shows very much improved effectiveness in high temperature naphthenic acid corrosion inhibition, of each of the two mixtures (A+B) and (A+C), as compared to effectiveness of each of the compounds. A, B and C separately. The very much improved effectiveness of the inhibiting compound of present invention, that is of either of mixtures (A+B) or (A+C) is seen from the very high corrosion inhibition efficiency, even with reduction in the total dosage of the active components. Tables 1 to 3 show the results of effectiveness of compound A, for three different molar ratio of high Reactive Polyisobutylene to Phosphorus Pentasulphide, such as 1:1, 1:0.5 and 1:0.25. Table 4 shows results of effectiveness of compound A with molar ratio of Normal Polyisobutylene to Phosphorus Pentasulphide, such as 1:0.35. Table 5 shows results of effectiveness of compound B that is, Tributyl Phosphate, as commercially available, without any solvent. Table 9 shows results of effectiveness of compound C, that is Di-isodecyl Phenyl Phosphite, as commercially available, without any solvent. Three tables 6 to 8 show effectiveness of the additive compound comprising mixture (A+B) of present invention, with two molar ratios 1:1 and 1:0.5 of two components of A, that is, High Reactive Polyisobutylene and Phosphorus Pentasulphide. Table 10 shows effectiveness of the additive compound comprising mixture (A+C) of present invention, with molar ratio of 1:1 of High Reactive Polyisobutylene and Phosphorus Pentasulphide. Discussion about Very High Effectiveness of Mixture (A+B), that is, Additive Compound of Present Invention, in Naphthenic Acid Corrosion Inhibition a) Referring to Table 1, effective active dosage of compound A (molar ratio 1:1) of 300 ppm and 325 ppm were required to achieve corrosion inhibition efficiency of 95.75% and 99.67% respectively. b) Referring to Table 2, effective active dosage of compound A (molar ratio 1:0.5) of 250 ppm was required to achieve corrosion inhibition efficiency of 75.48%. c) Referring to Table 3, effective active dosage of compound A, (molar ratio 1:0.25) of 500 ppm and 750 ppm were required to achieve corrosion inhibition efficiency of 83.81% and 97.72% respectively. d) Referring to Table 4, effective active dosage of compound A, with normal polyisobutylene (molar ratio 1:0.35) of 300 ppm gave corrosion inhibition efficiency of only 54.39%. e) Referring to Table 5, effective active dosage of compound B, of 100 ppm gave corrosion inhibition efficiency of only 83:97%. f) In contract, referring to Table 6, total effective active dosage of mixture (A+B) of 150 ppm (75 ppm of A and 75 ppm of B) and 150 ppm (90% of A and 60 ppm of B) gave corrosion inhibition efficiency of 97.49% and 99.20% respectively. This clearly shows the inventiveness of the mixture (A+B) of present invention, as very high corrosion inhibition efficiency of about 97% and 99% are achieved with very low total effective active dosages the mixture (A+B), that is, 150 ppm. This will effect tremendous savings due to very low dosages of mixture. Discussion about Very High Effectiveness of Mixture (A+C), that is Additive Compound of Present Invention, in Naphthenic Acid Corrosion Inhibition. Referring to Table 9, effective active dosage of compound C, of 120 ppm and 150 ppm gave corrosion inhibition efficiency of 76.05% and 98.18%. In contrast with results presented in Table 1 to 9, as discussed above, total effective active dosages of mixture (A+C) of present invention of 200 ppm (140 ppm of A and 60 ppm of C) gave corrosion inhibition efficiency of 99.54%. This leads to large savings, when it is noted that compound C is very expensive as compared to compound A. Thus it is seen from the earlier discussion that the additive compounds formed by two separate mixtures, (compound A+compound B) and (compound A+compound C) of present invention used for corrosion-inhibition have the following important distinguishing feature, as compared to the prior art. The inventor of the present invention, after extensive experimentation, has surprisingly found that the two additive combination compounds, each used by the inventor, as additive that is, two combination compounds formed by two separate mixtures, (compound A+compound B) and (compound A+compound C) are both highly effective in high temperature corrosion inhibition, as shown by the experimental results given in Tables 1 to 11. The prior-art does not teach or suggest use of mixture (A+B) or mixture (A+C) in naphthenic acid corrosion inhibition or sulphur corrosion inhibition or any corrosion inhibition, in general. In view of the details given in foregoing description of the present invention, it will be apparent to a person skilled in the art that the present invention basically comprises the following items: Item 1 A high temperature naphthenic acid corrosion inhibiting composition comprising a chemical mixture of corrosion inhibiting amount of an olefin Phosphorus sulphur compound A with corrosion inhibiting amount of any organophosphorus compound selected from the group consisting of compound B, compound C and compound D; wherein said olefin Phosphorus sulphur compound A, is produced by reacting said olefin with Phosphorus pentasulphide in presence of catalytic amount of sulphur, capably forming a reaction mixture, with molar ratio of said olefin to said Phosphorus pentasulphide being between 1:0.05 to 1:1.5, preferably being 1:1; wherein said compound B is a phosphate ester of the formula wherein R 1 and R 2 are each independently selected from the group consisting of hydrogen and moieties having from one to thirty carbon atoms, and R 3 is a moiety having from one to thirty carbon items; and wherein said compound C is an aryl containing phosphite compound excluding nitrogen having a structure selected from the group consisting of wherein R 1 , R 2 and R 3 are C 6 to C 12 aryl or alkyl and at least one R group is an aryl radical; and wherein said compound D is a phosphonate. Item 2 A composition, as described in item 1, wherein said olefin is polyisobutylene, which is either high reactive or normal. Item 3 A composition, as described in item 1 and 2, wherein said olefin Phosphorus sulphur compound is arrived at, by stirring and heating said reaction mixture of item 1, to 160° C. under nitrogen gas purging, maintaining said reaction mixture between 160° C. to 180° C. for a period of 1 hour to 2 hours, raising temperature of said reaction mixture to from 185° C. to 250° C., preferably from 190° C. to 230° C., more preferably from 210° C. to 225° C. and maintaining said reaction mixture with raised temperature for 1 to 24 hours, preferably for 6 to 10 hours, cooling the reaction mass to 100° C. and purging nitrogen gas into reaction vessel to drive out the hydrogen sulphide gas, thereby resulting into said composition. Item 4 A composition according to item 1, 2 or 3 wherein said olefin is an optionally substituted hydrocarbon group. Item 5 A composition according to any one of the preceding items wherein said olefin is an optionally substituted alkyl or alkenyl group. Item 6 A composition according to any one of the preceding items wherein said olefin is an optionally substituted branched alkyl or alkenyl group. Item 7 A composition according to any one of the preceding items wherein said olefin has between 10 and 1000 carbon atoms. Item 8 A composition according to any one of the preceding items wherein said olefin has between 4 and 200 carbon atoms. Item 9 A composition according to any one of the preceding items wherein said olefin has a molecular weight of from 200 to 10,000. Item 10 A composition according to any one of the preceding items wherein said olefin has a molecular weight of approximately 200 to approximately 1300. Item 11 A composition, comprising said mixture of compound A and compound B of item 1 and 14, wherein said phosphate ester B is selected from group consisting of phosphate, diphosphate, triphosphate, and tributyl phosphate, preferably tributyl phosphate. Item 12 A composition, as described in item 1, wherein said aryl containing phosphite compound C is selected from the group consisting of triphenyl phosphite, diphenyl phosphite, diphenyl isodecyl phosphite, diphenyl isooctyl phosphite, di-isodecyl phenyl phosphite and mixtures thereof, preferably di-isodecyl phenyl phosphite. Item 13 A composition, as described in item 12, wherein said tributyl phosphate is of a type which is commercially available. Item 14 A composition, as described in item 14, wherein said di-isodecyl phenyl phosphite is of a type which is commercially available. Item 15 A composition, as described in items 1, 11 and 13, wherein the amount of said mixture of compound A and compound B, which should be added to crude oil for high temperature naphthenic acid corrosion inhibition, is from about 1 ppm to about 5000 ppm, preferably from about 1 ppm to about 300 ppm. Item 16 A composition, as described in item 15, wherein the ratio of compound A to compound B, by weight, is from about 0.1:2 to about 2:0.1. Item 17 A composition, as described in items 1, 12 and 14, wherein the amount of said mixture of compound A and compound C, which should be added to crude oil for high temperature naphthenic acid corrosion inhibition, is from about 1 ppm to about 5000 ppm, preferably from about 1 ppm to about 300 ppm. Item 18 A composition, as described in item 17 wherein the ratio of compound A to compound C, by weight, is from about 0.1:2 to about 2:0.1. Item 19 A composition, as described in item 1, wherein the amount of mixture of compound A and compound D, which should be added to the crude oil for high temperature naphthenic acid corrosion inhibition, is from about 1 ppm to about 5000 ppm, preferably from about 1 ppm to 300 ppm. Item 20 A composition, as described in item 19, wherein the ratio of compound A to compound D, by weight, is from about 0.1:2 to about 2:0.1. Item 21 A process for high temperature naphthenic acid corrosion inhibition and/or high temperature sulphur corrosion inhibition of metallic surfaces of any of the hydrocarbon, processing units, with said processing units comprising distillation columns, strippers, trays, pump around piping and related equipments, using inhibitor combination compound such as, any mixture from three mixtures, such as, a mixture of two compounds A and B of item 1, 2, 11 and 13, or a mixture of two compounds A and C of items 1, 2, 12 and 14, and a mixture of two compounds A and D of items 1, 2, 19 and 20, comprising the steps of: a. heating the hydrocarbon containing naphthenic acid and/or sulphur compounds, to vapourize a portion of said hydrocarbon; b. condensing a portion of the hydrocarbon vapours, passing through said hydrocarbon processing unit, to produce a condensed distillate; c. adding to said distillate, before said condensed distillate is returned to said hydrocarbon processing unit or collected as a product, from about 1 ppm to about 5000 ppm, preferably from about 1 ppm to 300 ppm of said inhibitor combination compound such as, any mixture from three mixtures, such as, said mixture of two compounds A and B of item 1, 2, 11 and 13, or said mixture of two compounds A and C of items 1, 2, 12 and 14, and said mixture of two compounds A and D of items 1, 2, 19 and 20, wherein ratio by weight of A to B is from about 0.1:2 to about 2:0.1 and ratio of A to C is from about 0.1:2 to about 2:0.1. and ratio by weight of A to D is from about 0.1:2 to about 2:0.1; d. allowing said condensed distillate containing said inhibitor combination compound such as, any mixture from three mixtures, such as, said mixture of two compounds A and B of item 1, 2, 11 and 13, or said mixture of two compounds A and C of items 1, 2, 12 and 14, and said mixture of two compounds A and D of items 1, 2, 19 and 20, to contact said metallic surfaces of said hydrocarbon processing unit, to form a protective film on said surfaces whereby each surface is inhibited against corrosion; and e. allowing said condensed distillate to return to said hydrocarbon processing unit, or to be collected as said product. Although the invention has been described with reference to certain preferred embodiments, the invention is not meant to be limited to those preferred embodiments. Alterations to the preferred embodiments described are possible without departing from the spirit of the invention. However, the process and composition described above are intended to be illustrative only, and the novel characteristics of the invention may be incorporated in other forms without departing from the scope of the invention.

The present invention relates to the field of processing hydrocarbons which causes corrosion in the metal surfaces of processing units. The invention addresses the technical problem of high temperature naphthenic acid corrosion and sulphur corrosion and provides a solution to inhibit these types of corrosion. The three combination compositions are formed by three mixtures separately, with one mixture obtained by mixing compound A, which is obtained by reacting high reactive polyisobutylene (HRPIB) with phosphorous pentasulphide in presence of catalytic amount of sulphur with compound B such as trialkyl phosphate and second mixture obtained by mixing compound A with compound C such as phosphite like di-isodecyl phenyl phosphite, and third mixture obtained by mixing compound A with compound D such as a phosphonate, wherein each of these three mixtures independently provide high corrosion inhibition efficiency in case of high temperature naphthenic acid corrosion inhibition and sulphur corrosion inhibition. The invention is useful in all hydrocarbon processing units, such as, refineries, distillation columns and other petrochemical industries.

FIELD OF THE INVENTION [0001] The present invention relates to a hand-guided or stationary power tool having a drive unit, in particular a battery-operated power tool, e.g., a cordless screwdriver. BACKGROUND INFORMATION [0002] There are various known power tools that may be operated using an electric motor. In some cases these power tools are provided with EC motors that are brushless, i.e., the rotor is provided with permanent magnets that rotate in a magnetic field generated by stator coils. The rotational speed of the EC motor is usually controlled via the applied motor voltage. [0003] The motor voltage is usually applied by pulse width modulation of the power transistors of the drive unit. In doing so, the motor is commutated as a function of fixed rotor positions. The EC motor is usually designed for the maximum rotational speed of the power tool. Because this is usually associated with a lower number of required windings, it results in a comparatively low torque in relation to the stator current. This current is determined by the limiting values of the power electronics, the motor and/or the battery. The torque is thus also limited to this maximum value over the entire rotational speed range. [0004] This behavior is unfavorable for use of such EC motors in power tools. In this situation, it is often necessary for a high torque to be available at a low rotational speed and for a low torque to be available at a high rotational speed. With today's power tools, this is achieved by providing reversible gears with which a high torque at a high rotational speed is converted into a lower rotational speed of the tool to achieve a high torque at a lower rotational speed. However, it is complex and expensive to provide a reversible gear, which also results in friction losses that increase the power tools' power consumption. [0005] In the past, power tools have been designed for a high rotational speed, so the stator coils have a low ohmic resistance and a lower inductance, which may result in a relatively high current when the coils are short-circuited, and consequently the motor or the electronics may be damaged. In the event of a fault or an inadmissible operating state, which may occur, for example, when a battery is removed from a battery-operated power tool when the motor is rotating, the motor and/or the electronics may be destroyed due to short circuiting of the motor. For this reason, measures are usually provided to prevent damage to the motor. [0006] An object of the present invention is to provide an improved power tool that meets the requirements of a high torque at a lower rotational speed and a lower torque at a high rotational speed without using a reversible gear and whereby the power tool is more resistant to damage due to faults or inadmissible operating states. SUMMARY OF THE INVENTION [0007] According to the present invention, a power tool having a drive unit is provided, including a motor having a rotor with a permanent magnet and a stator. The drive unit also has a motor control designed to trigger the motor in a first rotational speed range according to a voltage-controlled mode and to trigger the motor in a second rotational speed range following the first rotational speed range in the direction of a higher rotational speed according to a field-weakening operation. [0008] With the power tool according to the present invention, the motor rotational speed is to be adjusted via the voltage-controlled mode as well as via the field-weakening operation. This has the advantage that the motor no longer needs to be designed electrically for a maximum rotational speed but instead may be designed for a medium rotational speed, so that a correspondingly higher torque may be achieved at the same maximum voltage in the range up to the medium rotational speed than with a traditional motor designed for a higher rotational speed. Higher torques are thus possible in the lower (first) rotational speed range. The motor is operated in field-weakening operation to achieve a high rotational speed beyond the medium rotational speed. In field-weakening operation, there is a change in the phase relation of the rotor field and the stator field, so that the rotational speed may be increased to a rotational speed that is higher than the maximum rotational speed in voltage-controlled operation. The higher rotational speed is achieved at a reduced torque in comparison with the torque at the maximum voltage. This operating performance is advantageous for power tools because they require either a high torque at a low rotational speed or a high rotational speed at a low torque. The drive unit may thus cover working ranges which are possible with conventional drives or conventionally operated EC motors only by using corresponding reversible gears. Due to the motor being designed for a comparatively low motor rotational speed, i.e., a motor rotational speed lower than the maximum rotational speed at which the power tool is to be operated at maximum speed, the resistance and inductance of the stator winding are higher in comparison with those of a traditional power tool. The stator winding may thus be designed to be short-circuit-proof. The motor may thus be short-circuited by the electronics for immediate stoppage in any operating state without the risk of damaging the motor or electronics due to short-circuit currents. In a fault scenario or in inadmissible operating states caused by sudden removal of the power supply when the motor is rotating, for example, short-circuiting of the motor by the power electronics of the drive is thus sufficient to leave the dangerous operating states by the fastest way possible. [0009] In field-weakening operation, the time characteristic of the motor currents approaches the sinusoidal form increasingly and thus reduces the increased pulsation losses in the magnet and iron of the motor, so the power tool may be operated more efficiently. [0010] Another advantage is that the stator windings are provided with a large number of windings so that a smaller wire diameter may be selected for the windings, thereby simplifying production of the motor. [0011] According to one specific embodiment of the present invention, the motor control applies a voltage to the motor in voltage-controlled mode to preselect the rotational speed of the motor. The first rotational speed range is determined by the range between 0 and the medium preselected rotational speed, which is achieved by applying a maximum voltage in voltage-controlled mode. [0012] The motor control of the power tool may have a phase shifter to adjust field-weakening operation through the phase shift between the stator magnetomotive force and the rotor magnetomotive force. The phase shifter may be designed in particular to adjust the phase between the stator magnetomotive force and the rotor magnetomotive force (between electric loading of the stator and electric loading of the rotor) to be greater than 90° in field-weakening operation. [0013] According to a preferred specific embodiment, the power tool has a power supply in the form of a rechargeable battery. In particular, the power tool may be designed as a cordless screwdriver, whereby a shaft of the motor is coupled to a machining tool by a gear having a fixed gear ratio, i.e., the power tool is designed without a reversible gear. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 shows a block diagram of a drive unit for a power tool. [0015] FIG. 2 shows vector diagrams to illustrate voltage-controlled operation and field-weakening operation. [0016] FIG. 3 shows a diagram to illustrate the plot of torque as a function of rotational speed with a traditional power tool and with a power tool according to one specific embodiment of the present invention. DETAILED DESCRIPTION [0017] FIG. 1 shows a drive unit 1 for a power tool, in particular for a battery-operated power tool, in particular a cordless screwdriver. The drive unit has a motor 2 which is supplied with power via power electronics 3 . Motor 2 is triggered by pulse-width-modulated voltage pulses generated with the help of transistor bridges, producing an effective voltage on motor 2 . Motor 2 is designed as a three-phase motor having three stator windings 4 , each triggered by one of the transistor bridges. [0018] Power electronics 3 is triggered via a motor control 5 , generating PWM triggering signals for power electronics 3 in a PWM unit 6 . PWM triggering signals are set in PWM unit 6 as a function of the position of a rotor (not shown) of motor 2 and as a function of a setpoint value externally preselected with the help of a regulating unit 7 . [0019] The setpoint value is directly or indirectly preselected by a user with the help of an operating element. [0020] The position of the rotor of motor 2 is measured by a position sensor 8 so that information about the absolute position of the rotor is available in regulating unit 7 . Position sensor 8 measures the position either absolutely or in relation to a previous position, the absolute position being determined in regulating unit 7 in this case via the changes in position. [0021] Regulating unit 7 is designed in such a way that two modes are implemented. In a first mode, motor 2 is triggered according to a voltage-controlled mode, so that the rotational speed, in particular the rotational speed at no load or at a constant load, is proportional to the effective voltage applied via power electronics 3 . In a second mode, which is determined by a rotational speed range above a preselected rotational speed, regulating unit 7 switches to the so-called field-weakening operation during regulating the power electronics for triggering motor 2 . A phase shifter 9 is provided for this purpose, ensuring that the phase relation between the rotor field supplied by the rotor and the exciting field created by the stator is greater than 90°, the degree of phase shifting determining the rotational speed. [0022] Motor control 5 may be designed in the form of a microcontroller supplying the triggering signals of power electronics 3 . Drive unit 1 may be supplied with power via a battery 10 , in particular a rechargeable battery. Regulating unit 7 may continue to detect the stator currents and the voltages in power electronics 3 to obtain information about the load applied to motor 2 . [0023] FIG. 2 shows vector diagrams for the stator and rotor magnetomotive force for voltage-controlled operation as well as for field-weakening operation. The vector diagram on the left represents the status in voltage-controlled operation. In this mode, the maximum achievable motor rotational speed is fixedly preselected by the level of the supply voltage applied to the power electronics. The vector of the stator current and/or stator magnetomotive force θ 1 is thus almost perpendicular to the vector of the magnetic equivalent magnetomotive force of rotor θ PM . The rotational speed may be adjusted almost proportionally by varying the applied voltage on the stator windings. [0024] The vector diagram on the right side of FIG. 2 represents the status in a field-weakening operation. The vector of stator magnetomotive force θ 1 and the vector of magnetic equivalent magnetomotive force θ PM of the rotor are no longer mutually perpendicular but instead the stator and rotor magnetomotive force each now have an angle of much more than 90°. When the stator magnetomotive force is broken down vectorially into a component parallel to the rotor magnetomotive force (X axis) and a component perpendicular to that (Y axis), it is thus apparent that the X-axis component of stator magnetomotive force θ 1,x is opposite the rotor magnetomotive force and thus diminishes its effect. This effect is a reduction in synchronized internal voltage. The operative mechanism corresponds to the mechanism known from a separately excited d.c. shunt-wound machine. If the excitation strength is reduced during operation of the machine, this causes a reduction in the rotationally induced armature voltage, resulting in an increase in armature current and thus an accelerating torque. The machine accelerates until the induced voltage and the voltage drop on the armature resistance are in equilibrium with the feed voltage. This allows the rotational speed of the d.c. machine to increase. [0025] FIG. 3 shows the curves of torque as a function of motor rotational speed. With a traditional drive unit (dashed line) for a power tool of a conventional design having an EC motor, the available torque is largely constant up to the maximum torque, because it is determined by the current limit of the electronics and the motor. [0026] With the power tool according to the present invention (solid line), the voltage-controlled mode is likewise selected in a first rotational speed range, with the motor of the power tool being designed to obtain the maximum torque at a medium rotational speed nm, determined by the maximum available power and/or the maximum permissible current limit. As a result, a higher torque is available at the same current level than with a traditional power tool even at a lower rotational speed in the range of 0 to n M because of the greater number of windings. In the second rotational speed range, i.e., at a rotational speed between n M and n Max (maximum rotational speed), the motor is operated in field-weakening operation in which a lower torque is available than the maximum torque achieved at a medium rotational speed. The greater the rotational speed of the motor, the lower the torque, decreasing inversely proportionally until reaching maximum rotational speed n Max . [0027] The torque characteristic curve corresponds to a characteristic curve which is very suitable for operation of power tools. In traditional power tools, such a characteristic curve is usually achieved by using a gear having reversible gear ratios, which provides high torques in the lower rotational speed range and lower torques in the high rotational speed range. The power tool according to the present invention therefore has the advantage that it may be designed without a reversible gear and therefore the friction losses due to the gear may be avoided. Furthermore, such a power tool allows a sturdier design of the stator windings, which may be short-circuited in any operating state by the electronics due to their greater resistance and inductance without the risk of damage to the motor or electronics. The higher resistance and inductance result from the fact that, at a given maximum voltage in voltage-controlled operation, the motor may be designed for a lower rotational speed because the higher rotational speed is achievable via field-weakening operation.

A hand-guided or stationary power tool has a drive unit having a motor that includes a rotor having a permanent magnet and a stator and has a motor control designed to trigger the motor in a first rotational speed range according to a voltage-controlled mode and to trigger the motor in a second rotational speed range following the first rotational speed range in the direction of a higher rotational speed according to a field-weakening operation.

[0001] The subject matter herein generally relates to a housing that indicates consumer disassembly. BACKGROUND [0002] A label is pasted on an electronic device to illustrate whether the electronic device has been privately disassembled during a warranty period. However, the label may also be damaged with normal use of the electronic device, and this may void the warranty. BRIEF DESCRIPTION OF THE DRAWINGS [0003] Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. [0004] FIG. 1 is an isometric view of a housing with a consumer disassembly indication structure in accordance with a first embodiment. [0005] FIG. 2 is a cross sectional view of the housing, taken along line II-II of FIG. 1 . [0006] FIG. 3 is an exploded, isometric view of the housing of FIG. 1 . [0007] FIG. 4 is another exploded, isometric view of the housing of FIG. 1 . [0008] FIG. 5 is another isometric view of a housing with a consumer disassembly indication structure in accordance with a second embodiment. [0009] FIG. 6 is a cross sectional view of the housing, taken along line VI-VI of FIG. 5 . [0010] FIG. 7 is an exploded, isometric view of the housing of FIG. 5 , wherein the consumer disassembly indication structure includes a connecting body. [0011] FIG. 8 is an enlarged isometric view of the connecting body of FIG. 7 . [0012] FIG. 9 is another exploded, isometric view of the housing of FIG. 5 , wherein the consumer disassembly indication structure includes a plurality of switches. [0013] FIG. 10 is an enlarged diagrammatic view of the plurality of switches of FIG. 9 . DETAILED DESCRIPTION [0014] It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure. [0015] Several definitions that apply throughout this disclosure will now be presented. [0016] The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “substantially” is defined to be essentially conforming to the particular dimension, shape or other word that substantially modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. [0017] The present disclosure is described in relation to a housing for incontrovertibly indicating a private disassembly of the housing. [0018] FIGS. 1-2 illustrate a housing 10 of the disclosure which indicates consumer disassembly. The housing 10 includes a circuit board 30 , a consumer disassembly indication structure 40 , a first shell 21 , and a second shell 22 detachably connectable with the first shell 21 . A substantially enclosed space 20 is defined to house a product (not shown). The circuit board 30 and the consumer disassembly indication structure 40 are located between the first shell 21 and the second shell 22 . [0019] FIGS. 3-4 illustrate that the first shell 21 includes a plurality of positioning members 210 protruding from an inner face of the first shell 21 facing the circuit board 30 . The plurality of positioning members 210 includes a pair of first positioning members 211 , and a pair of second positioning members 212 . Each positioning member 210 defines a receiving space 2101 . [0020] The consumer disassembly indication structure 40 includes a computer chip 41 , a plurality of switches 42 , a plurality of connecting bodies 43 , and a plurality of elastic members 44 . The computer chip 41 and the plurality of switches 42 are fixed on the circuit board 30 . The plurality of elastic members 44 and the connecting bodies 43 are received in the receiving spaces 2101 . Each of the plurality of elastic members 44 generates an elastic force on the connecting bodies 43 that enables the connecting bodies 43 to couple with the switches 42 . [0021] Each of the plurality of switches 42 is in an off state, and is electrically connected with the computer chip 41 by the circuit board 30 . The plurality of switches 42 includes two first switches 421 corresponding to the pair of first positioning members 211 , and two second switches 422 corresponding to the pair of second positioning members 212 . [0022] The plurality of connecting bodies 43 include a pair of conductive bodies 431 which are made of conductive materials, and a pair of insulative bodies 432 which are made of isolated materials. When the first shell 21 is coupled with the second shell 22 , the pair of conductive bodies 431 are respectively fixed on the pair of first positioning members 211 and are resisted by the elastic members 44 , so that the conductive bodies 431 are electrically coupled with the first switches 421 keeping the pair of first switches 421 turned on, and the pair of insulative bodies 432 are respectively fixed on the pair of second positioning members 212 and are resisted by the elastic members 44 to couple with the second switch 422 keeping the pair of second switches 422 turned off. The conductive bodies 431 and insulative bodies 432 have a same structure. [0023] When the first shell 21 is separated from the second shell 22 by an operation from a user, the elastic members 44 are elastically recovered to separate the conductive bodies 431 and the insulative bodies 432 from the positioning members 21 that make the connecting bodies 43 disconnect from the switches 42 . The structures of the conductive bodies 431 and the insulative bodies 432 are identical, and precise reinstatement of the conductive bodies 431 with the first positioning members 211 cannot easily be achieved by the user. The probability is that, in attempted reassembly after the separation, the conductive body 431 can be fixed on a second positioning member 212 rather than on a first positioning member 211 , and the insulative connecting body 432 can be fixed on a first positioning member 211 rather than on a second positioning member 212 . Thus, the conductive bodies 431 cannot be electrically coupled with the first switches 421 . [0024] The computer chip 41 is configured to record and output the connections between the conductive body 431 and the first switch 421 , and to generate signals according to the connections. The connection relationships of the conductive body 431 and the first switch 421 can include a first connection relationship in which the conductive body 431 is fixed on the first positioning member 211 to make the conductive body 431 couple with the first switch 421 and the insulative body 432 is fixed on the second positioning member 212 to make the insulative body 432 couple with the second switch 422 . A second connection relationship can be that the conductive body 431 is not fixed on the first positioning member 211 or that the insulative body 432 is not fixed on the second positioning member 212 . The generated signals include a first signal generated according to the first connection relationship, and a second signal generated according to the second connection relationship. In this embodiment, when the second signal is generated, the housing 10 is rendered incapable of functioning. [0025] Thus, the question of whether the housing 10 has been opened can be determined by accessing the computer chip 41 . [0026] In the embodiment, the number of the conductive bodies 431 is two. The number of the insulative bodies 432 is two. In other embodiments, the number of the conductive bodies 431 and the insulative bodies 432 can be more than two. [0027] FIGS. 5-10 illustrate another embodiment of the housing 10 to inhibit consumer disassembly of the disclosure. The housing 10 includes a circuit board 30 , a consumer disassembly indication structure 40 , a first shell 21 , and a second shell 22 detachably connectable with the first shell 21 to define a substantially enclosed space 20 to house the product. The consumer disassembly indication structure 40 and the circuit board 30 are located between the first shell 21 and the second shell 22 . [0028] The first shell 21 includes a pair of positioning members 210 protruding from a surface of the first shell 21 facing the circuit board 30 . Each positioning member 210 defines a receiving space 2101 and one or more grooves 60 . [0029] The consumer disassembly structure 40 includes a computer chip 41 , two groups of switches 42 electrically coupled with the computer chip 41 , a pair of connecting bodies 43 , and a pair of elastic members 44 . The computer chip 41 and the two groups of switches 42 are positioned on the circuit board 30 . The pair of elastic members 44 and the pair of connecting bodies 43 are received in the receiving space 2101 . The connecting bodies 43 are resisted by the elastic members 44 to couple with the switches 42 . [0030] Each connecting body 43 includes a conductive body 431 which can conduct electricity, and an insulative body 432 which are electrically isolated. The conductive body 431 is secured on an end of the insulative body 432 , and a size of the conductive body 431 is smaller than that of the insulative body 432 . The insulative body 432 includes a projection engaged with the groove 60 to limit the insulative body 432 on the positioning member 210 . [0031] FIGS. 7-8 illustrate that each group of switches 42 includes a first switch 421 and one or more second switches 422 . The first switch 421 and one or more second switches 422 are arranged on the circuit board 30 in a ring. When the first shell 21 is coupled with the second shell 22 , the projection is engaged with one of the grooves 60 allowing the conductive body 431 to electrically couple with the first switch 421 to allow conduction, and to couple the insulative body 432 with the second switches 422 keeping the second switches 422 turned off [0032] When the first shell 21 is separated from the second shell 22 by an operation of a user, the elastic members 44 are elastic recovered to separate the connecting bodies 43 from the positioning members 21 making the conductive body 431 disconnect from the first switch 421 . There are various assembly relationships between the grooves 60 and the projection, so precise reinstatement of the conductive body 431 with the first switch 211 cannot be easily achieved by the user. The probability is that, in attempted reassembly after the separation, the conductive body 431 can be electrically coupled with the second switch 422 rather than the first switch 421 , and the insulative connecting body 432 can be coupled with the first switch 421 rather than the second switch 422 . [0033] The computer chip 41 is configured to record and output the connections between the conductive body 431 and the first switch 421 , and to generate signals according to the connections. The connection relationships of the conductive body 431 and the first switch 421 can include a first connection relationship in which the conductive body 431 is coupled with the first switch 421 , and a second connection relationship can be that the conductive body 431 is not coupled with the first switch 421 . The generated signals include a first signal generated according to the first connection relationship, and a second signal generated according to the second connection relationship. In this embodiment, when the second signal is generated, the housing 10 is rendered incapable of functioning. [0034] Thus, the question of whether the housing 10 has been opened can be determined by accessing the computer chip 41 . [0035] The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a housing. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set fourth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.

A housing containing its own record of any private and unwarranted disassembly includes a first shell, a second shell detachably connected with the second shell, a consumer disassembly indication structure. The consumer disassembly indication structure includes a circuit board, a plurality of switches, a computer chip, a plurality of conductive bodies, and a plurality of insulative bodies. The plurality of switches are fixed on the circuit board and each is electrically connected with the computer chip. The computer chip is configured to record electric connections between the conductive bodies and switches, the original electric connections being changed to other or no connections after any disassembly of the housing.

RELATED APPLICATIONS This is a non-provisional patent application based on provisional application Ser. No. 60/144,999, filed Jul. 22, 1999. REFERENCE OF COMPUTER PROGRAM LISTING APPENDIX This application contains a computer program listing, attached as Appendix A. This appendix has been submitted on a single compact disc (in duplicate which contains Appendix A in a file named “09452825. APPENDIX A.txt” of size 33 KB created on May 17, 2002. The material contained in this file is hereby incorporated by reference. FIELD OF THE INVENTION The present invention relates to a method and apparatus for prediction of system reliability, and in particular, to a method and apparatus that can be used to predict reliability of complex systems composed of many components. BACKGROUND OF THE INVENTION A system is by definition a combination of interrelated elements (or components) designed to work as a coherent entity. During use, one or more of these elements may fail, thus causing the entire system or part of a system, to fail. The times at which such failures will occur are unknown, but it is often possible to determine the probability of failure for the individual elements and from these to determine the reliability of the system of the whole. Reliability studies are extremely important in engineering design. The ability to compute the reliability of a system or subsystem enables designers to identify and address those systems more likely to fail. For example, as is well known in the art, the ability to compute a subsystem's or component's reliability is critical to numerous aspects of production quality control and manufacturing efficiency. Furthermore, as is also well known in the art, system reliability can directly impact system design when safety is a primary concern. For example, a television manufacturer desires to make certain that its product will likely remain operational for an extended period of time, such as ten years. A fire detection system should remain operational for even longer, such as thirty years. If a product developer has developed two competing designs for a product, it wishes to know the reliability of each design to make its decision as to the preferred design. Reliability predictions rely heavily on principles of probability. As systems become more complex and contain larger numbers of elements, the problems of reliability become more difficult and take on added significance. In turn, as the number of elements grows larger, the difficulty in computing system reliability grows exponentially. Various approaches have been taken to deal with system reliability. Approaches range from actual testing of the product to computation of the exact system reliability. Some of these approaches are patented. For example, one methodology used to actually test the product is disclosed in U.S. Pat. No. 5,548,718 in which a mapping mechanism and automated testing system are used for testing software functionality. U.S. Pat. No. 5,014,220 discloses a reliability model generator which aggregates low level reliability models into a single reliability model based on the desired system architecture. In the past, numerous approaches to estimate system reliability of complex systems have been proposed since computation of the actual reliability is monumental or impractical for systems composed of many components. However, these prior art approaches have distinct limitations. One such approach well known in the art was proposed by Aven. (Aven, T., “Reliability/Availability Evaluation of Coherent System based on Minimal Cut Sets”, Reliability Engineering , 13, 93-104 (1986)). Aven attempted to compute exact system reliability using a method based on minimal cut sets. A cut set is a set of components, which by failing causes the whole system to fail. A cut set is minimal if it cannot be reduced without losing its status as a cut set. The prominent shortcoming of this approach is that the method depends on the initial choices of two parameters. Any error introduced in the initial choice of these parameters would propagate through the computation. As a result, as the system being studied grew larger, the accuracy of the approach declined. Further, the method of Aven is unable to deal with the case when the component survival functions belong to the Increasing Failure Rate Average (IFRA) class of life distributions. The IFRA class is defined as follows: a life distribution function F is said to belong to an IFRA class if −(1/t) log (1−F(t) is non-decreasing in t≧0. It is known to be the most important class of life distributions. The well-known distributions like Exponential, Weibull, and Lognormal are included in this class. Another approach used often in industry is the Barlow & Proschan bound (“B-P bound”) in which bounds are placed on system reliability. (Barlow, R. E. and F. Proschan, Statistical Theory of Reliability and Life Testing , Holt, Rinehart and Winston Inc, New York (1975).) The B-P bound approach is limited because it is, after all, a bound, and thus cannot predict the exact system reliability. Also, the bound is not valid on the entire real line. The bound is point-wise. Further, the B-P bound approach cannot deal with the IFRA case. Yet another approach has been to resort to minimum or maximum bounds of a system's reliability. The min-max bounds approach is limited because they are bounds, and thus cannot predict exact system reliability. Also, the min-max bounds cannot deal with the IFRA case. Further, the min-max bounds require the knowledge of both path and cut sets. However, these approaches are inherently inaccurate as they seek only to give upper and lower values rather than to predict exact reliability of the system. Accordingly, in many applications where cost or accuracy are critical, such results are inadequate. In an effort to minimize the increasing inaccuracy of these approaches as the complexity of a system increases, it is well known in the art to divide a complex system into subsystems each having fewer components, and to compute the reliability of each subsystem. The aforementioned U.S. Pat. No. 5,014,220, takes such an approach by dividing a complex system into simpler subsystems based on the use of a knowledge database. Although the general approach of computing “sub-reliability” addresses the inherent difficulty of computing reliability of complex systems, this approach introduces additional error into the computation, as each sub-reliability must be joined with the others to yield the reliability of the entire system. Since this joinder is usually inaccurate, it introduces error into the calculation of reliability. Thus, for complex systems determination of the exact reliability of the system is extremely difficult and sometimes thought to be impossible to determine. It is therefore desired to develop an approach to determine exact system reliability which accurately calculates the reliability of even very complex systems without being computationally burdensome. The desired approach should be easy to implement and to use, should not require that the system be dissected into subsystems for determination of reliability, and should not be dependent on selection of parameters whose inaccurate selection is detrimental to the determination of reliability. Further, the method should predict exact reliability rather than bounds on the reliability. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a block diagram of a series structure that can be analyzed according to the method of the present invention. FIG. 2 shows a graph of reliability importance as a function of time for the components of the series structure of FIG. 1 . FIG. 3 shows a graph comparing the exact reliability (i.e., the reliability predicted according to the method of the present invention), and the Min-max bounds, B-P bounds, and Chaudhuri bounds of reliability as a function of time for the structure of FIG. 1 . FIG. 4 shows a block diagram of a parallel structure that can be analyzed according to the method of the present invention. FIG. 5 shows a graph of the reliability importance as a function of time for the components of the parallel structure of FIG. 4 . FIG. 6 shows a graph comparing the exact reliability, Min-max bounds, B-P bounds, and Chaudhuri bounds as a function of time for the structure of FIG. 4 . FIG. 7 shows a block diagram of a 2-out-of-3 structure that can be analyzed according to the method of the present invention. FIG. 8 shows a graph of the reliability importance as a function of time for the components of the 2-out-of-3 structure of FIG. 7 . FIG. 9 shows a graph comparing the exact reliability, Min-max bounds, B-P bounds, and Chaudhuri bounds as a function of time for the structure of FIG. 7 . FIG. 10 shows a block diagram of a bridge system that can be analyzed according to the method of the present invention. FIG. 11 shows a graph of the reliability importance as a function of time for the components of the bridge system of FIG. 10 . FIG. 12 shows a graph comparing the exact reliability, Min-max bounds, B-P bounds, and Chaudhuri bounds as a function of time for the bridge structure of FIG. 10 . FIG. 13 shows a block diagram of a fire detector system that can be analyzed according to the method of the present invention. FIG. 14 shows a graph of the reliability importance as a function of time for the components of the fire detection system of FIG. 13 . FIG. 15 shows a graph comparing the exact reliability, Min-max bounds, B-P bounds, and Chaudhuri bounds as a function of time for the fire detection system of FIG. 13 . FIG. 16 shows a block diagram of one embodiment of the apparatus for predictions of system reliability according to the present invention. SUMMARY OF THE INVENTION The method of the present invention comprises the steps of: (a) identifying the minimal path set of components which must function for the system to function; (b) constructing a minimal path set matrix by representing the minimal path sets as binary numbers in the matrix; (c) performing an OR operation on the minimal path set matrix's rows; (d) selecting the columns of the minimal path set matrix in pairs and performing an OR operation on their respective rows; (e) appending the corresponding column to the minimal path set matrix; (f) repeating step (d) with the three columns and performing an OR operation on their respective rows; (g) appending the column resulting from step (f) to the minimal path set matrix; (h) repeating the selection, ORing and appending for increasingly larger sets of columns in accordance with the procedures of steps (c), (d) and (e) until the size is equal to the total number of minimal path sets to construct a design matrix, (i) constructing a vector of ones having signs based on the position in the vector; and (j) calculating the system reliability from the design matrix, vector of ones, and reliabilities of the individual components of the system. The structure function of the system is calculated from the design matrix, vector of ones, and the states of the components of the system. The present invention is capable of accurately predicting system reliability of complex systems composed of many components and is easy to implement and to use. In addition, the method of the present invention avoids many of the shortcomings of prior art systems, for the method does not require dissection of the system into subsystems, is not based on arbitrary or inaccurate parameters, and is a prediction of exact reliability, not bounds on reliability. The apparatus of the present invention comprises a processor for performing most of the steps of the method. It is possible for the minimal path sets and the total number of minimal path sets to be determined by the processor, or may be input from another processor or by a human. Results are provided on output devices well known in the art. The apparatus need not be special equipment, but rather may be a personal computer commonly used. DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a representation for the structure function of a coherent system, which is suitable for computer implementation is first determined. Since a structure function determines a system uniquely, a method for determining system reliability based on its representation is presented herein. Section 1 presents some notations, definitions and prior art theorems for bounds on reliability. The method of the present invention is described in Section 2. Section 3 discusses the following aspects: (i) the illustration of the method of the present invention through some well known structures such as series, parallel, k-out-of-n, and a fire detector system, (ii) the computation of some important reliability measures (Birnbaum's structural and reliability importance) for such structures and, (iii) the application of Chaudhuri bound, Barlow and Proschan bound, and the Min-max bounds to these structures for comparison to the exact system reliability determined according to the method of the present invention. These bounds are implemented for the above mentioned structures. It is found that the use of the Chaudhuri bound has an edge over the other methods. The apparatus for predicting system reliability of the present invention is discussed in Section 4, and some conclusions about the method and apparatus are set forth in Section 5. 1. NOTATIONS, DEFINITIONS, AND PRIOR ART THEOREMS FOR BOUNDS ON RELIABILITY a. Notations In the description of the method of the present invention, the following notations are used: Notation Description n Number of components x (x l ,...,x n )′, the states of the components Φ(x) The state of the system X i Indicator variable denoting the state of the i th component p l P(X i = 1), the reliability of the i th component h P(Φ(x) = 1), the reliability of the system (.;x)′ (x 1 , x 2 ,..., x i+l ; ,., x i+l ,..., x n )′ h(p) h is a function of p = (p l ,...,p n ), when the components are independent I h (i) Reliability importance of the i th component B Φ (i) Birnbaum measure of structural importance of the i th component {overscore (F)}(t) The survival function, 1-F(t), where F(t) is the system life distribution Let X i denote the state of the i th component so that X i = { 1 0  if     the          th     component     is     working otherwise Let Φ({tilde under (x)}) denote the structure function of the system so that Φ     ( x ) = { 1 0  if     the     system     is     working otherwise b. Definitions The following defined terms are used throughout the description of the method of the present invention: Coherent System: A system is said to be coherent if all its components are relevant and the structure function is increasing in each argument. Minimal Path Sets: A path set is a set of components of a system, which by functioning ensures that the system is functioning. A path set is said to be minimal if it cannot be reduced without losing its status as a path set. Minimal Cut Sets: A cut set is a set of components, which by failing causes the whole system to fail. A cut set is said to be minimal if it cannot be reduced without losing its status as a cut set. Birnbaum's Reliability Importance: The Birnbaum's measure of reliability importance of component i, denoted by i h (i), is given by I h  ( i ) = ∂ h  ( p ~ ) ∂ p i = h  ( 1 i , p ~ ) - h  ( 0 i , p ~ ) Birnbaum's Structural Importance: The Birnbaum's measure of structural importance of component i, denoted by B Φ (i), is given by B Φ  ( i ) = [ h  ( 1 i , p ∼ ) - h  ( 0 i , p ∼ ) ] p j = 1 2 , j ≠ i OR operation: The OR operation, denoted by ⊕, is performed on two binary numbers in the following way: (i) 0⊕0=0 (ii) 1⊕0=1 (iii) 0⊕1=1 (iv) 1⊕1=1 b. Prior Art Theorems for Bounds on Reliability For purposes of discussion of prior art theorems for bounds on reliability, let a coherent system consist of n statistically independent components. It is well known that if the life distributions of all these components belong to the Increasing Failure Rate Average (IFRA) class, then the life distribution of the system also belongs to the IFRA class. Below are three prior art theorems for predicting system reliability for a coherent system. Theorem 1: Chaudhuri Bound: The Chaudhuri bound is obtained on the reliability function of a coherent system consisting of independent components with IFRA distributions. (Chaudhuri G., Deshpande, J. V. and A. D. Dharmadhikari, A. D., “Some Bounds on Reliability of Coherent Systems of IFRA Components”, Journal of Applied Probability , 28, 709-714 (1991).) Specifically, let F i (t) have IFRA life distributions and 0<a<∞ for i=1, . . . , n. Then, if h({overscore (F)} 1 ,(t), . . . ,{overscore (F)} n (t)) denotes the survival function of a coherent system, then: h  [ F _ 1  ( t ) , …    , F _ n  ( t ) ]     { ≥ h     ( [ F _ 1  ( a ) ] t / a , …    , [ F _ n  ( a ) ] t / a )     for     t ≤ a ≤ h     ( [ F _ 1  ( a ) ] t / a , …    , [ F _ n  ( a ) ] t / a )     for     t ≥ a for 0<a<∞ and t>0 where n is the number of components in the system. The elegance of the Chaudhuri bound is that it is valid on the entire real line. The choice of a depends on the customer's specification. The bounds here exploit the knowledge of some quantile of the component distribution functions. Theorem 2: Min-max Bounds: Let Φ be a coherent structure with state variables x l , . . . ,x n . Denote the minimal path sets by P 1 , . . . ,P m and the minimal cut sets by K l , . . . ,K k . Then max 1 ≤ j ≤ m  P     ( min i ∈ P j     X i = 1 ) ≤ P  ( Φ     ( X ~ ) = 1 ) ≤ min 1 ≤ j ≤ k  P     ( max i ∈ K j     X i = 1 )    If, in addition, it is assumed that x l , . . . ,x n are associated, then max 1 ≤ j ≤    m  ∏ i ∈    P j  p i ≤ P  ( Φ     ( X ∼ ) = 1 ) ≤ min 1 ≤ j ≤    k  ∏ i ∈ K j  p i where p i =P(X i =1), the reliability of component i, ∏ i = 1 n     p i = p 1  p 2     …     p n ,    and    ∏ i = 1 n  p i = 1 - ( 1 - p 1 )     ( 1 - p 2 )     …     ( 1 - p n ) . As used herein, the Min bound of the Min-Max bound is the upper bound, while the Max bound is the lower bound. Theorem 3: Barlow-Proschan Bound (B-P Bound): Let F be IFRA with mean μ. Then, for fixed t>0: F _  ( t ) ≤ { 1  - ω     t  for     t ≤ μ for     t > μ where ω>0, satisfies: 1 −ωμ=e −ωt 2. THE METHOD OF THE PRESENT INVENTION The method of the present invention is described in the following steps: Step 1: Identify the minimal path sets of the coherent structure under study. For a given minimal path set, form a vector v of dimension n (the number of components in the system ) as: v i = { 1 0  if          th     component     of     the     system     belongs     to     the     minimal     path     set otherwise Then, construct matrix P=(v {tilde under (1)} , v {tilde under (2)} , . . . ,v {tilde under (m)} ) n×m , where v j corresponds to the j th minimal path set, j=1, . . . ,m. P will be called the minimal path set matrix. Step 2: Select the columns of the minimal path set matrix P in pairs and perform an OR operation on their respective rows. There are (  m 2 )  such column combinations. At the end of each OR operation, the resulting column is appended to P, leading to the following matrix: ( P , P 1 ) n × ( m + ( m 2 ) ) In the above operation, the order in which pairs of columns are chosen is not important. All that is required is that all possible pairs of columns are ORed and the resulting columns appended to P. Step 3: Now take all possible sets of three columns of P at a time and do an OR operation on their respective rows. At the end of this step, there will be (  m 3 )  new columns that will be appended to (P,P 1 ) to yield ( P , P 1 , P 2 ) n × ( m + ( m 2 ) + ( m 3 ) ) Step 4: Repeat step 2 taking i, i=4, . . . ,m columns of P at a time. In the very last step, all m columns of P will be ORed with each other resulting in the following matrix: D = ( P , P 1 , P 2 , …    , P m - 1 ) n × ( m + ( m 2 ) + ( m 3 ) + … + ( m m ) ) = ( P , P 1 , P 2 , …    , P m - 1 ) n × ( 2 m - 1 )  D will be called the design matrix. Step 5: Construct a vector {tilde under (1)} of ones of dimension 2 m −1 whose first m elements are 1's, the next ( m 2 )   entries have signs (−1) 2−1 =−1, followed by ( m 3 )   entries with signs (−1) 3−1 =+1, and so The last ( m m )   entry has sign (−1) m−1 . In general, the signs are determined according to the rule (−1) i−1 , where i denotes the number of columns of P that are taken at a time to be ORed in a particular step. Step 6: Obtain the structure function of the system by: Φ     ( x ∼ ) = ∑ j = 1 2 m - 1     1 ∼     ( j ) · ∏ i = 1 n     x i D     ( i , j )  where D(i,j) denotes the (i,j)th element of D. Step 7: Hence, letting {tilde under (p)} be the vector of component reliabilities, the system reliability is then given by: h     ( p ∼ ) = ∑ j = 1 2 m - 1     1 ∼     ( j ) · ∏ i = 1 n     p i D     ( i , j )     0 < p i < 1  where 1(j) is the j th element of {tilde under (1)}. Since the minimal path sets uniquely determine a coherent structure, the representation of the structure function is unique. Collectively, steps 2 through 4 may be expressed as the steps required to create design matrix D. If the number of minimal path sets is 1, then the design matrix is the minimal path set matrix, i.e., D=P if m=1. If the number of minimal path sets is greater than 1, then all possible sets of columns of the matrix are ORed and the results appended to the original minimal path set matrix. Initially, the size of the set of columns is two. After all sets of size 2 have been ORed and the results appended to the matrix, the size of the sets to be selected, ORed, and appended is increased by 1. This is repeated for all set sizes up through and including a set size equal to the total number of minimal path sets on. Of course, only one selection, ORing and appending will be required when the set size is equal to the total number of minimal path sets m. It will be appreciated by those of skill in the art that the determination of the structure function in step 6 is not essential to determination of the reliability of the system. Steps 1 through 6 alone can be used to determine the system reliability of the complex system. However, determination of the structure function may be desirable to verify the accuracy of the method of the present invention. 3. SOME ILLUSTRATIVE EXAMPLES In this section, the method of the present invention is further explained through application of the method to the following well known coherent structures (systems): series, parallel, 2-out-of-3 and bridge structures. In addition, for a practical application, a fire detector system is considered as well. Also, computed for each of these systems are the values of the Birnbaum structural importance and Birnbaum reliability importance. Example 1 Series System Referring now to FIG. 1, there is shown a block diagram of a series structure that can be analyzed according to the method of the present invention. As an example of the method of the present invention, consider the series system with two independent Weibull components shown in FIG. 1 . This series has the survival function exp     ( - t α i β i ) ,    i = 1 , 2. The structure function of the system is given by Φ({tilde under (x)})= x 1 x 2 Now, the application of the method of the present invention for this system is as follows: Step 1: The system has only one path set: {1,2}. Hence, P = ( 1 1 ) 2 × 1 Steps 2, 3 and 4: There is only one column in P, hence no OR operations are required in this instance. Therefore, the Design matrix is: D = ( 1 1 )     and Step 5: The vector of ones is. 1 ∼ = ( 1 ) Step 6: To verify the accuracy of the method of the present invention, the structure function of the system is: Φ     ( x ∼ ) = ∑ j = 1 1     1     ( j )     ∏ i = 1 2     x i D     ( i , j ) = 1 · x 1 1     x 2 1 = x 1     x 2  which agrees with the known structure function set forth above. Step 7: The exact system reliability (the term “exact system reliability” as used herein and in the drawings refers to the system reliability as predicted according to the method of the present invention) is simply determined by the relationship: h     ( p ∼ ) = ∑ j = 1 2 m - 1     1 ∼     ( j ) · ∏ i = 1 n     p i D     ( i , j )     0 < p i < 1 The resulting system reliability is discussed below in comparison to prior art bounds on reliability as determined by prior art methods. Calculations for Prior Art Methods To compare the results of the present method to those of prior art methods, calculations are necessary to determine the bounds for reliability according to the prior art methods (Chaudhuri bounds, B-P bounds, and minimum and maximum bounds), values for a, α i and β i are necessary, where a is an unknown parameter of the life distribution in question, α i is the shape parameter of the Weibull distribution for component i (an unknown parameter normally estimated from sample data), and β i is scale parameter of the Weibull distribution for component i (an unknown parameter normally estimated from sample data), and where i is index parameter for the n components of the system. The best candidate for a is the mean life of the system, or mean time to failure, MTTF. This quantity is computed using the following integral: a = MTTF = ∫ 0 ∞  F _     ( t )      t = ∫ 0 ∞  h  [ F _ 1     ( t ) , …    , F _ n     ( t ) ]      t . The values of α i and β i are given in the following vectors for both components. alpha=[1.3 1.5]′ beta=[1.0 1.0]′ The above integral can only be solved numerically by the trapezoidal or Simpson rules. The following steps not only compute the MTTF, but they dynamically change the upper bound of the integral so that when the value of MTTF does not improve by more than a threshold, the integration stops. Step a: Set the lower and upper limits of the integral to t lb =0 and t ub =1, respectively. Set the stepsize=0.25, old_MTTF=0, δ=0.001, and t=0. Step b: Set the time slice for integration to Δt=(t ub −0)/100. Step c: Compute the values of F _ i     ( t ) = exp     ( - t α i β i ) ,    i = 1 , 2 ,  for both components. Step d: Use the {overscore (F)} i (t) values as vector p and compute h(p) as discussed earlier. Step e: Save the current values of t and h(p) in two arrays, x and h, respectively. Step f: Increment t by Δt, i.e. t=t+Δt. Step g: If t≦t ub , go to step c; otherwise, go to step h. Step h: Do numerical integration to compute MTTF using x and h arrays. Step i: If |MTTF−old_MTTF|<δ, then stop; otherwise, go to step j. Step j: Set old_MTTF=MTTF. Set the new t ub =t ub +stepsize, go to step b. Once the value of a=MTTF is computed, the h array contains the exact reliability function over the time interval from 0 to the last value of t ub . To compute the reliability bounds, similar steps as above are taken with slight modifications. Step A: Set t=0. Step B: Compute the values of [ F _ i     ( a ) ] t / a = [ exp     ( - t α i β i ) ] t / a ,    i = 1 , 2 ,  for both components. Step C: Use the [{overscore (F)} i (a)] t/a values as vector p and compute h(p) as discussed earlier. Step D: Save the current value of h(p) in array b. Step E: Increment t by Δt, i.e. t=t+Δt, where Δt is the same as that of the last iteration of MTTF computation. Step F: If t≦t ub , go to step B; otherwise, stop. The variable definitions used for the MATLAB implementation of the method of the present invention are: pathset: minimal path set matrix, P cutset: minimal cut set matrix D: The design matrix, D reliab: system reliability simportnc: vector of structural importance rimportnc: vector of reliability importance alpha: Shape parameter of the Weibull distribution beta: Scale parameter of the Weibull distribution last_t: t ub in the reliability calculation, the largest value of t at which the area under the exact reliability curve changes less than a very small amount The values of the variables for the MATLAB implementation of the method of the present invention for the series structure of FIG. 1 are: pathset = 1 1 cutset = 1 0 0 1 D = 1 1 simportnc = [ 0.5 0.5 ] ′ rimportnc = [ 0.95 0.95 ] ′ alpha = [ 1.3 1.5 ] ′ beta = [ 1 1 ] ′ last_t = 2.25 It will be appreciated by those of skill in the art that not all of these variables are required for determination of the system reliability according to the present invention. Only the variables pathset (the minimum path set matrix) and comprel (component reliability) are required. The design matrix D can be calculated in a program rather than input as a matrix to the program. FIG. 2 shows a graph of reliability importance as a function of time for the components of the series structure of FIG. 1 . The slight difference between the two reliability importance functions is due to the different values of α, the shape parameter of the Weibull distribution. Table 1 (below) lists the values of exact system reliability and its various bounds at several time points. TABLE 1 Comparison of the exact system reliability, Chaudhuri bound, B-P, and Min-max bounds. Time Exact Min Max Chaudhuri B-P t reliability bound bound bound bound 0.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.1125 0.9083 0.9083 0.9433 0.8370 1.0000 0.2250 0.7784 0.7784 0.8660 0.7005 1.0000 0.3375 0.6442 0.6442 0.7838 0.5863 1.0000 0.4500 0.5189 0.5189 0.7018 0.4907 1.0000 0.5625 0.4085 0.4085 0.6229 0.4107 0.9348 0.6750 0.3152 0.3152 0.5489 0.3438 0.6643 0.7875 0.2389 0.2389 0.4804 0.2877 0.4724 0.9000 0.1780 0.1780 0.4181 0.2408 0.3451 1.0125 0.1307 0.1307 0.3610 0.2015 0.2574 1.1250 0.0945 0.0945 0.3032 0.1687 0.1950 1.2375 0.0675 0.0675 0.2524 0.1412 0.1497 1.3500 0.0476 0.0476 0.2083 0.1182 0.1160 1.4625 0.0331 0.0331 0.1706 0.0989 0.0907 1.5750 0.0228 0.0228 0.1385 0.0828 0.0714 1.6875 0.0155 0.0155 0.1117 0.0693 0.0565 1.8000 0.0104 0.0104 0.0894 0.0580 0.0449 1.9125 0.0070 0.0070 0.0710 0.0485 0.0359 2.0250 0.0046 0.0046 0.0560 0.0406 0.0287 2.1375 0.0030 0.0030 0.0439 0.0340 0.0231 2.2500 0.0019 0.0019 0.0342 0.0285 0.0186 FIG. 3 compares the exact reliability function, Min-max bounds, B-P bound, and Chaudhuri bounds as a function of time for the series system of FIG. 1 . As shown in FIG. 3, in the case of series structure, the lower bound of Min-Max is the same as the exact reliability. Example 2 Parallel System Referring now to FIG. 4, there is shown a block diagram of a parallel structure that can be analyzed according to the method of the present invention. Consider the parallel structure with two independent Weibull components as shown in FIG. 4 having survival functions exp     ( - t α i β i ) , i=1,2. The structure function of the system is given by Φ  ( x ∼ ) = x 1 + x 2 - x 1  x 2 ( 4.2 ) The system has the following minimal path sets: {1}, {2} Step 1: Thus, The P matrix is: P = ( 1 0 0 1 ) 2 × 2 Step 2: D = ( 1 0 1 0 1 1 ) Step 3: Since P has only two columns, D above results. Step 4: Not necessary in this case. Step 5: 1 ∼ = [ 1 1 - 1 ] ′ Step 6: Φ     ( x ) ∼ = ∑ j = 1 3     1 ∼     ( j )     ∏ i = 1 2     x i D     ( i , j ) = 1 ∼     ( 1 )     x 1 D     ( 1 , 1 )     x 2 D     ( 2 , 1 ) + 1 ∼     ( 2 )     x 1 D     ( 1 , 2 )     x 2 D     ( 2 , 2 ) + 1 ∼     ( 3 )     x 1 D     ( 1 , 3 )     x 2 D     ( 2 , 3 ) Φ  ( x ∼ ) = 1  x 1 1  x 2 0 + 1  x 1 0  x 2 1 + ( - 1 )  x 1 1  x 2 1 = x 1 + x 2 - x 1  x 2  Φ( {tilde under (x)} )=1 x 1 1 x 2 0 +1 x 1 0 x 2 1 +(−1) x 1 1 x 2 1 =x 1 +x 2 −x 1 x 2 which agrees with known structure function for the parallel structure set forth above. The values of the variables used for the MATLAB implementation of the method of the present invention for the parallel structure of FIG. 4 are: pathset = 1 0 0 1 cutset = 1 1 D = 1 0 1 0 1 1 simportnc = [ 0.5 0.5 ] ′ rimportnc = [ 0.05 0.05 ] ′ alpha = [ 1.3 1.5 ] ′ beta = [ 1 1 ] ′ last_t = 4 FIG. 5 shows a graph of the reliability importance as a function of time for the components of the parallel structure of FIG. 4 . Table 2 lists the values of the exact reliability and its various bounds at several time points. TABLE 2 Comparison of the exact system reliability, Chaudhuri bound, B-P, and Min-max bounds. Time Exact Min Max Chaudhuri B-P t reliability bound bound bound bound 0.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.2000 0.9901 0.9144 0.9901 0.9610 1.0000 0.4000 0.9414 0.7765 0.9414 0.8732 1.0000 0.6000 0.8504 0.6283 0.8504 0.7664 1.0000 0.8000 0.7308 0.4889 0.7308 0.6574 1.0000 1.0000 0.6004 0.3679 0.6004 0.5548 1.0000 1.2000 0.4745 0.2815 0.4745 0.4628 1.0000 1.4000 0.3628 0.2125 0.3628 0.3827 0.8161 1.6000 0.2697 0.1585 0.2697 0.3144 0.6186 1.8000 0.1958 0.1168 0.1958 0.2570 0.4760 2.0000 0.1393 0.0852 0.1393 0.2093 0.3723 2.2000 0.0975 0.0616 0.0975 0.1699 0.2950 2.4000 0.0673 0.0441 0.0673 0.1376 0.2363 2.6000 0.0460 0.0313 0.0460 0.1113 0.1910 2.8000 0.0311 0.0221 0.0311 0.0898 0.1555 3.0000 0.0209 0.0154 0.0209 0.0725 0.1274 3.2000 0.0139 0.0107 0.0139 0.0584 0.1050 3.4000 0.0093 0.0074 0.0093 0.0470 0.0869 3.6000 0.0061 0.0051 0.0061 0.0378 0.0722 3.8000 0.0040 0.0034 0.0040 0.0304 0.0602 4.0000 0.0027 0.0023 0.0027 0.0245 0.0503 FIG. 6 compares different bounds with respect to the exact reliability for the parallel system of FIG. 4 . In the case of the parallel structure, the upper bound of Min-Max is the same as the exact reliability. Example 3 2-out-of-3 System Referring now to FIG. 7, there is shown a block diagram of a 2-out-of-3 structure that can be analyzed according to the method of the present invention. Consider the 2-out-of-3 structure with three independent Weibull components shown in FIG. 7 having survival functions exp     ( - t α i β i ) ,    i = 1 , 2 , 3. The structure function of the system is given by Φ  ( x ∼ ) = x 1  x 2 + x 1  x 3 + x 2  x 3 - 2  x 1  x 2  x 3 ( 4.3 ) The system has the following minimal path sets:  {1,2}, {1,3}, {2,3} Step 1: Thus, The P matrix is: P = ( 1 1 0 1 0 1 0 1 1 ) 3 × 3 Step 2 through 4: The final D matrix is: D = ( 1 1 0 1 1 1 1 1 0 1 1 1 1 1 0 1 1 1 1 1 1 ) Step 5: The vector of ones is: 1 ∼ = [ 1 1 1 - 1 - 1 - 1 1 ] ′ Step 6: The structure function is: Φ     ( x ∼ ) =    1     x 1 1     x 2 1     x 3 0 + 1     x 1 1     x 2 0     x 3 1 + 1     x 1 0     x 2 1     x 3 1 - 1     x 1 1     x 2 1     x 3 1 - 1     x 1 1     x 2 1     x 3 1 -    1     x 1 1     x 2 1     x 3 1 + 1     x 1 1     x 2 1     x 3 1 =    x 1     x 2 + x 1     x 3 + x 2     x 3 - 2  x 1     x 2     x 3 which agrees with known structure function identified above. The values of the variables for the MATLAB implementation of the method of the present invention for the 2-out-of-3 systems of FIG. 7 are: pathset = 1 1 0 1 0 1 0 1 1 cutset = 1 1 0 1 0 1 0 1 1 D = 1 1 0 1 1 1 1 1 0 1 1 1 1 1 0 1 1 1 1 1 1 simportnc = [ 0.5 0.5 0.5 ] ′ rimportnc = [ 0.095 0.095 0.095 ] ′ alpha = [ 1.3 1.5 1.7 ] ′ beta = [ 1 1 1 ] ′ last_t = 2.5 FIG. 8 shows a graph of the reliability importance as a function of time for the components of the 2-out-of-3 system of FIG. 7 . Table 3 below lists the values of the exact reliability and its various bounds at several points in time. TABLE 3 Comparison of the exact system reliability, Chaudhuri bound, B-P, and Min-max bounds. Time Exact Min Max Chaudhuri B-P t reliability bound bound bound bound 0.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.1250 0.9943 0.9293 0.9972 0.9675 1.0000 0.2500 0.9610 0.8027 0.9821 0.8916 1.0000 0.3750 0.8900 0.6581 0.9500 0.7958 1.0000 0.5000 0.7859 0.5162 0.9006 0.6945 1.0000 0.6250 0.6620 0.3891 0.8367 0.5960 1.0000 0.7500 0.5332 0.2829 0.7624 0.5050 1.0000 0.8750 0.4120 0.1988 0.6822 0.4237 0.8994 1.0000 0.3064 0.1353 0.6004 0.3526 0.6936 1.1250 0.2201 0.0945 0.5086 0.2915 0.5367 1.2500 0.1531 0.0650 0.4218 0.2397 0.4221 1.3750 0.1034 0.0439 0.3430 0.1963 0.3364 1.5000 0.0681 0.0293 0.2739 0.1601 0.2710 1.6250 0.0437 0.0192 0.2152 0.1301 0.2203 1.7500 0.0275 0.0125 0.1664 0.1055 0.1804 1.8750 0.0169 0.0080 0.1270 0.0854 0.1487 2.0000 0.0102 0.0050 0.0956 0.0689 0.1232 2.1250 0.0061 0.0031 0.0712 0.0555 0.1026 2.2500 0.0036 0.0019 0.0525 0.0447 0.0858 2.3750 0.0021 0.0012 0.0383 0.0359 0.0720 2.5000 0.0012 0.0007 0.0277 0.0288 0.0606 FIG. 9 compares different bounds with respect to the exact reliability for the 2-out-of-3 system of FIG. 7 . At the MTTF, the Chauduri bound and exact reliability are the same for the 2-out-of-3 system. Example 4 Bridge System Referring now to FIG. 10, there is shown a block diagram of a bridge system that can be analyzed according to the method of the present invention. Consider the bridge structure with five independent Weibull components shown in FIG. 10 having survival functions exp     ( - t α i β i ) , i=1, . . . ,5. The structure function of the system is given by Φ  ( x ∼ ) = x 1  x 4 + x 2  x 5 + x 1  x 3  x 5 + x 2  x 3  x 4 - x 1  x 2  x 4  x 5 - x 1  x 3  x 4  x 5 - x 1  x 2  x 3  x 4 - x 1  x 2  x 3  x 5 - x 2  x 3  x 4  x 5 + 2  x 1  x 2  x 3  x 4  x 5 ( 4.4 ) The system has the following minimal path sets: {1,4}, {2,5}, {1,3,5}, {2,3,4} Step 1: Thus, The P matrix is: P = ( 1 0 1 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 0 ) 5 × 4 Step 2 through 4: The D matrix is: D = ( 1 0 1 0 1 1 1 1 0 1 1 1 1 1 1 0 1 0 1 1 0 1 1 1 1 1 1 1 1 1 0 0 1 1 0 1 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 0 1 1 1 1 1 1 1 0 1 1 0 1 1 0 1 1 1 1 1 1 1 1 ) Step 5: The vector of ones is: 1 ∼ = [ 1 1 1 1 - 1 - 1 - 1 - 1 - 1 - 1 1 1 1 1 - 1 ] ′ Step 6: The structure function is: Φ     ( x ∼ ) = 1  x 1 1     x 2 0     x 3 0     x 4 1     x 5 0 + 1  x 1 0     x 2 1     x 3 0     x 4 0     x 5 1 + 1  x 1 1     x 2 0     x 3 1     x 4 0     x 5 1 + 1  x 1 0     x 2 1     x 3 1     x 4 1     x 5 0 - 1  x 1 1     x 2 1     x 3 0     x 4 1     x 5 1 - 1  x 1 1     x 2 0     x 3 1     x 4 1     x 5 1 - 1  x 1 1     x 2 1     x 3 1     x 4 1     x 5 0 - 1  x 1 1     x 2 1     x 3 1     x 4 0     x 5 1 - 1  x 1 0     x 2 1     x 3 1     x 4 1     x 5 1 - 1  x 1 1     x 2 1     x 3 1     x 4 1     x 5 1 + 1  x 1 1     x 2 1     x 3 1     x 4 1     x 5 1 + 1  x 1 1     x 2 1     x 3 1     x 4 1     x 5 1 + 1  x 1 1     x 2 1     x 3 1     x 4 1     x 5 1 + 1  x 1 1     x 2 1     x 3 1     x 4 1     x 5 1 - 1  x 1 1     x 2 1     x 3 1     x 4 1     x 5 1 = x 1     x 4 + x 2     x 5 + x 1     x 3     x 5 + x 2     x 3     x 4 - x 1     x 2     x 4     x 5 - x 1     x 3     x 4     x 5 - x 1     x 2     x 3     x 4 - x 1     x 2     x 3     x 5 - x 2     x 3     x 4     x 5 + 2  x 1     x 2     x 3     x 4     x 5 which agrees with known structure function for the bridge system set forth above. The values of the MATLAB variables for the bridge system of FIG. 10 are: pathset = 1 0 1 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 0 cutset = 1 0 1 0 1 0 0 1 0 0 1 1 0 1 0 1 0 1 1 0 D =  Columns     1     through     12 1 0 1 0 1 1 1 1 0 1 1 1 0 1 0 1 1 0 1 1 1 1 1 1 0 0 1 1 0 1 1 1 1 1 1 1 1 0 0 1 1 1 1 0 1 1 1 1 0 1 1 0 1 1 0 1 1 1 1 1 Columns     13     through     15 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 simportnc = [ 0.375 0.375 0.125 0.375 0.375 ] ′ rimportnc = [ 0.09321048     0.1038712     0.0104076     0.0651144      0.0756868 ] ′ alpha = [ 1.3 1.5 1.7 2.1 2.3 ] ′   beta = [ 1 1 1 1 1 ] ′   last_t = 2.25 FIG. 11 shows a graph of the reliability importance as a function of time for the components of the bridge system of FIG. 10 . Table 4 (below) lists the values of the exact reliability and its various bounds at several time points. TABLE 4 Comparison of the exact system reliability, Chaudhuri bound, B-P, and Min-max bounds. Time Exact Min Max Chaudhuri B-P t reliability bound bound bound bound 0.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.1125 0.9978 0.9567 0.9979 0.9813 1.0000 0.2250 0.9845 0.8702 0.9864 0.9299 1.0000 0.3375 0.9505 0.7571 0.9615 0.8559 1.0000 0.4500 0.8870 0.6305 0.9223 0.7693 1.0000 0.5625 0.7910 0.5025 0.8702 0.6784 1.0000 0.6750 0.6680 0.3831 0.8080 0.5893 1.0000 0.7875 0.5316 0.2791 0.7388 0.5055 1.0000 0.9000 0.3978 0.1942 0.6659 0.4294 0.8590 1.0125 0.2802 0.1297 0.5876 0.3619 0.6759 1.1250 0.1862 0.0866 0.4725 0.3030 0.5370 1.2375 0.1173 0.0559 0.3638 0.2524 0.4324 1.3500 0.0702 0.0349 0.2682 0.2094 0.3519 1.4625 0.0402 0.0210 0.1895 0.1731 0.2891 1.5750 0.0220 0.0123 0.1285 0.1427 0.2393 1.6875 0.0116 0.0069 0.0837 0.1174 0.1993 1.8000 0.0059 0.0038 0.0525 0.0965 0.1670 1.9125 0.0029 0.0020 0.0317 0.0792 0.1406 2.0250 0.0014 0.0010 0.0185 0.0649 0.1189 2.1375 0.0006 0.0005 0.0104 0.0532 0.1009 2.2500 0.0003 0.0002 0.0057 0.0435 0.0859 FIG. 12 compares different bounds with respect to the exact reliability for the bridge system of FIG. 10 . As with the 2-out-of-3 system, the Chaudhuri bound and the exact reliability are the same at the MTTF for the bridge system. Example 5 Fire Detector System Referring now to FIG. 13, there is shown a block diagram of a fire detector system that can be analyzed according to the method of the present invention. This pneumatic system is considered in Hoyland and Rausand at page 84. (Hoyland, A. and Rausand, M., System Reliability Theory, Models and Statistical Methods , Wiley, New York (1994).) The system consists of three parts: heat detection, smoke detection, and an alarm button operated manually. The reliability block diagram of the system is shown in FIG. 13 . In the heat detection section, there is a circuit with four identical fuse plugs, FP1, FP2, FP3, and FP4, which forces the air out of the circuit if they experience temperatures more than 72° C. The circuit is connected to a pressure switch (PS). The PS starts functioning once one or more of the plugs starts working and transmits a signal to the start relay (SR) to produce an alarm and thereby causing activation of a fire protection system. The smoke detection section has three smoke detectors SD1, SD2, and SD3. These detectors are connected to a voting unit VU through a logical 2-out-of-3. This means that at least two detectors must give a fire signal before the fire alarm is activated. For the successful transmission of an electric signal from heat detector/smoke detector, the DC source must be working. In the manual activation section, a human operator OP must always be present to activate the system. If the operator observes a fire, he/she turns on the manual switch MS to relieve pressure in the circuit of the heat detection section. This activates the PS switch, which in turn gives an electric signal to SR. Of course, DC should be in the functioning state. The system has the following 8 minimal path sets: {1,2,3,4,5}, {1,6,7,9,5}, {1,6,8,9,5}, {1,7,8,9,5}, {1,10,4,5}, {1,11,4,5},{1,12,4,5,}, {1,13,4,5} Since the computation of this system is rather involved and lengthy, a partial printout is provided. For example, the D matrix for this system has 2 8 −1=255 columns. The values of the variables for the MATLAB implementation of the method of the present invention for the fire detector system of FIG. 13 are: pathset = 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 1 1 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1    cutset     Columns     1     through     12 =    1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 1 1 1 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 1 0 1 1 0 0 0 1 1 0 0 1 0 1 1 0 1 0 0 0 1 1 0 0 1 1 0 1 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0 0 1 1 1 1 1 1 simportnc = [ 0.3037109375     0.0029296875     0.0029296875    0.787109375     0.3037109375     0.03271484375     0.03271484375 0.03271484375     0.0654296875     0.0087890625 ( 0.0087890625     0.0087890625     0.0087890625 ] ) ′ rimportnc = [ 0.81617055483750     0.00000604387862 0.00000597017279     0.11212102442168     0.77730529032143 0.02348713768035     0.02423116515824     0.02493497493462 0.10817190647499     0.00002250038183     0.00002475042002    ( 0.00002750046668     0.00003093802502 ] ) ′ alpha = [ 1.5     1.5     1.6     1.6     1.7     1.7     1.8     1.8     1.9     2.0     2.1     2.2     2.3 ] ′ beta = [ 1 1 1 1 1 1 1 1 1 1 1 1 1 ] ′ last_t = 2 FIG. 14 shows a graph of the reliability importance as a function of time for the components of the fire detection system of FIG. 13 . Table 5 lists the values of the exact reliability and its various bounds at several points in time. TABLE 5 Comparison of the exact system reliability, Chaudhuri bound, B-P, and Min-max bounds. Time Exact Min Max Chaudhuri B-P t reliability bound bound bound bound 0.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.1000 0.9494 0.9215 0.9689 0.8723 1.0000 0.2000 0.8536 0.7748 0.9144 0.7543 1.0000 0.3000 0.7327 0.6054 0.8485 0.6464 1.0000 0.4000 0.5989 0.4422 0.7765 0.5491 1.0000 0.5000 0.4640 0.3029 0.7022 0.4628 1.0000 0.6000 0.3398 0.1950 0.6283 0.3872 0.6936 0.7000 0.2347 0.1181 0.5567 0.3219 0.4946 0.8000 0.1526 0.0673 0.4889 0.2662 0.3624 0.9000 0.0932 0.0362 0.4258 0.2189 0.2710 1.0000 0.0533 0.0183 0.3679 0.1793 0.2060 1.1000 0.0285 0.0091 0.3085 0.1462 0.1585 1.2000 0.0142 0.0043 0.2558 0.1189 0.1232 1.3000 0.0066 0.0019 0.2097 0.0963 0.0966 1.4000 0.0029 0.0008 0.1700 0.0778 0.0763 1.5000 0.0012 0.0003 0.1364 0.0627 0.0606 1.6000 0.0005 0.0001 0.1082 0.0504 0.0483 1.7000 0.0002 0.0000 0.0850 0.0404 0.0387 1.8000 0.0001 0.0000 0.0661 0.0324 0.0311 1.9000 0.0000 0.0000 0.0509 0.0259 0.0251 2.0000 0.0000 0.0000 0.0388 0.0207 0.0203 FIG. 15 compares different bounds with respect to the exact reliability for the fire detection system of FIG. 13 . As was true with the 2-out-of-3 and bridge systems, the value of the Chaudhuri bound and the exact system reliability are the same at the MTTF for the fire detection system. 4. THE APPARATUS OF THE PRESENT INVENTION The method of the present invention is simple and easy to use. The method depends on the knowledge of the path sets of a given structure. Standard software packages are available (CAFTAN, Hoyland and Rausand (1994), p. 145) to provide the minimal path sets of any coherent system. The method of the present invention has been programmed in SAS, S-PLUS, and MATLAB. A MATLAB version of the code of one embodiment of the apparatus of the present invention is contained in Appendix A. This code can be executed on a personal computer of the type well known in the art. Input can be made to the system by a keyboard, scanner, or other input device well known in the art. The results can be output using a video display, LCD display, printer, or other output device well known in the art. A block diagram of a representative apparatus for practicing the method of the present invention is shown in FIG. 16 . In this embodiment, processor 40 serves as a means for performing most of the calculations required as is explained in greater detail herein. Input data file 42 and keyboard 44 serve as input devices to processor 40 , while output from processor 40 is sent to an output device such as output data file 46 , video display 48 , and/or printer 50 . Input data file 42 and/or keyboard 44 serve as means for inputting the minimal path sets and individual component reliability dater to processor 40 . As previously mentioned, programs such as CAFTAN may be executed to generate minimal path set data that may be included in input data file 42 or made available to a user for manual input to processor 40 by keyboard 44 . Alternately, the minimal path set data maybe determined manually or by another method well known in the art. Component reliability data may likewise be entered by an input device such as input data file 42 or keyboard 44 . During operation, minimal path set data and component reliability data is entered as described above and read by processor 40 . Either processor 40 then calculates the total number of minimal path sets, or, alternatively, the total number of minimal path sets is input though an input device. Processor 40 then serves as a means to construct the minimal path set matrix, a means to construct the design matrix, a means to construct the vector of ones, and the means to determine the system reliability as described in association with the above discussion of the method of the present invention. Processor 40 may also serve as a means for determining the structure function according to the method of the present invention. Processor 40 then outputs the reliability and/or structure function device to one or more output devices operatively connected to processor 40 . Shown in FIG. 16 are three such output devices—output data file 46 , video display 48 , and printer 50 . In the embodiment of FIG. 16, processor 40 comprises a personal computer having the Windows (™) operating system and running the MATLAB program attached hereto as Appendix A. Those of skill in the art will acknowledge that processor 40 may comprise various combinations of hardware and/or software as is well known in the art. For example, the MATLAB program could be embodied in hardware alone, other software programs could be used (including SAS and S-SPLUS or a program written in any computer or microprocessor language such as C), or other combinations of hardware and software may be used and still be within the scope of the invention. 5. CONCLUSIONS The method of the present invention yields a new representation of the structure function of a coherent system. This representation is useful in implementing Chaudhuri bounds, which are found to be advantageous when compared to the Min-max, Barlow and Proschan bounds on the system reliability most commonly used in practice. With the proposed representation of the structure function, the computations of important reliability measures such as Birnbaum's structural and reliability importance become easy. The method for predicting system reliability accurately calculates the reliability of even very complex systems without requiring burdensome calculations. The method is easy to implement and to use as exemplified by the apparatus of the present invention. Also, reliability is determined without dissection of the system into subsystems thereby avoiding the problem of introduced inaccuracies caused by joinder of such subsets. The method is not dependent upon selection of parameters which can adversely affect the result. Further, the exact system reliability is predicted—not bounds on reliability as is determined with prior art approaches. When it is known that the components have IFRA life, then the Chaudhuri bounds could be the best choice for the purpose of predicting reliability of a very complex coherent structure. The knowledge of some quantile of the component distributions is enough to obtain the Chaudhuri bounds, whereas in order to implement Min-max bounds, the complete description of the component life distributions is required. The Barlow-Proschan bound is not valid for the significant part of the system life and above all this bound is point-wise. It's also clear from the above examples that the Chaudhuri bounds do fairly well for the useful part of the system life. Thus, the use of the Chaudhuri bounds is recommended for general use. It will be appreciated by those of skill in the art that the method of the present invention results in a prediction of exact reliability, rather than the determination of upper and lower values. Thus, when accuracy and/or cost are critical, the present invention serves as a valuable tool for prediction of system reliability. It will be further appreciated that the method of the present invention is not dependent upon the selection of initial parameters thereby avoiding. inaccuracies resulting from the selection of such parameters. It will be still further appreciated that the method of the present invention does not require the system to be divided into sub-systems, thereby avoiding the inaccuracies resulting from the joinder of sub-reliabilities. It will be yet further appreciated that the present invention can be utilized to evaluate the reliability of complex systems while maintaining the advantages of being easy to implement and to use.

A method and apparatus for prediction of system reliability is disclosed. The method comprises the steps of: (a) identifying the minimal path set of components which must function for the system to function; (b) constructing a minimal path set matrix by representing the minimal path sets as binary numbers in the matrix; (c) constructing a design matrix from OR operations on sets of columns of the minimal path set matrix whose results are appended to the original minimal path set matrix; (d) constructing a vector of ones having signs related to the position in the vector; and (e) calculating the system reliability from the design matrix, vector of ones and the reliabilities of each of the components of the system. The method of the present invention also determines the structure function of the system from the design matrix, vector of ones, and the states of the components of the system. The apparatus for performing the method of the present invention comprises a programmable processor. The present invention is capable of accurately predicting system reliability of complex systems composed of many components and is easy to implement and to use.

CROSS-REFERENCE TO RELATED APPLICATION The instant application is a national phase of International patent application number PCT/IB2008/052067, filed May 26, 2008, which claims priority to IT PI2007A000063, filed May 28, 2007, the entire specifications of all of which are expressly incorporated herein by reference. FIELD OF THE INVENTION The present invention concerns an apparatus for physiotherapy and postural education/reducation. In particular the invention concerns an apparatus for performing passive lumbar stretching exercises. DESCRIPTION OF THE PRIOR ART Many pathologies causing more or less severe and/or chronic lumbar pain are often treated by physiokinesis therapy together with other specific therapies. Strongly recommended treatments provide assuming analgetic postures able to decompress the lumbar intervertebral disks. There are two main types of apparatus or physiotherapy devices specifically designed to perform such kind of treatments. A first type consists of beds provided with belts or other means able to restrain on one side the upper part of the body and on the other side the legs laying on the bed, the bed being able to stretch the lumbar vertebras by gradually moving away the upper and lower sections of the bed itself. In this way is obtained a passive stretching of the lumbar disks that maintained for some minutes and regularly repeated produces beneficial effects in many pathologies causing lumbar pain. Nevertheless the use of such type of beds is not always recommended: in fact, many pathologies have to be treated by assuming analgetic postures with flexion. That is the case, for instance, of many lumbar stenosis, which require treatments in which the passive stretching of the intervertebral disks is associated with a reduction of the lumbar lordosis. The apparatus known in the prior art which is able to carry on in the best way that function is the one known with the name of “analgetic lumbar positioner” that allows the decompression of the disks reducing at the same time the lumbar stenosis. The “analgetic lumbar positioner is a device substantially consisting of a vertical column rested to a base and comprising leg supporting members apt to restrain the lower part of the legs in a horizontal position at a height from the ground which can be adjusted by turning a handle mounted on top of the column and acting upon a rack. In order to perform the treatment the patient is requested to laid down close to the “analgetic lumbar positioner”, to bend its legs at an angle of 90° with respect to its body and to put the lower section of the legs on the leg supporting members of the apparatus. Once fastened the lower section of the legs the handle is turned to move up the leg supporting members until the lumbar section of the patient's back moves away from the ground of few centimeters as a result of the traction of the legs. The traction phase may lasts some minutes after that the trainer goes back to the patient and turns the handle in the opposite direction in order to move down the leg supporting members. The treatment may be repeated several times and, obviously frequent treatment sessions can be performed. Such apparatus is, in the prior art, the one normally known and used in the medic and physiotherapy sector in order to perform the above described treatments. Unfortunately the “analgetic lumbar positioner” has a limit in the fact that the treatment cannot be autonomously performed by the patient since the manual driving of the handle moving the leg supporting members implies the presence of a physiotherapist or another person in order to assist the patient during the treatment. Such limit, that is the need of a continuous assistance during the treatment, is certainly responsible for the lack of popularity of an apparatus which is particularly efficient for performing the specific kind of treatment for which it is designed. It is so clear how important is to look for solutions allowing the autonomous execution of treatments providing passive intervertebral disks decompression with reduction of the lumbar stenosis, without the need of external assistance. SUMMARY OF THE INVENTION Aim of this invention is to propose a high efficient apparatus for performing passive lumbar stretching, which can be used both in physiotherapy or gym centres and in private houses. further aim of the invention is to propose an “analgetic lumbar positioner” with improved structure, enabling a completely autonomous execution of treatments providing passive intervertebral disks decompression with reduction of the lumbar stenosis. Such aims are attained through an apparatus for performing passive lumbar stretching treatments, the apparatus comprising at least a supporting structure where leg supporting members can move in a substantially vertical direction, said leg supporting members being apt to support the lower section of a person's legs, the movement of said leg supporting members being obtained thanks to effecting means which can be controlled by the person that is under treatment at the apparatus. Advantageously said leg supporting members move along said supporting structure in a direction which is inclined of about 10° with respect of a vertical line. The supporting structure is advantageously provided with at least a base and at least a substantially vertical column. According to a preferred embodiment the supporting structure is bound at a longitudinal end of a bed comprising a frame and a lay surface supporting the body of the person under treatment, said lay surface being able to horizontally, longitudinally translate with respect to said frame. The horizontal translation is obtained thanks to the fact that the frame of the bed is provided with one or more longitudinal guides along which move wheels integral to the bottom of the lay surface. Alternatively, according to a preferred embodiment, a lay surface supporting the person's back is hinged to the base, said lay surface being rotatable from a position in which it is substantially horizontal to a closed position in which it is substantially vertical, so minimizing the overall dimensions of the apparatus. Advantageously, near the end where it is hinged, said lay surface provides revolving members freely rotating around an horizontal axis, said revolving members being arranged and sized so that when the lay surface is in the horizontal position said revolving members don not touch the ground, whilst, when the lay surface is in the vertical position, said revolving members touch the ground and the base is supported by said revolving members. Advantageously the leg supporting members move along the supporting structure thanks to at least one vertical worm screw integral to the supporting structure and turned by an electric motor, said worm screw being coupled with a nut integral to the leg supporting members. Alternatively the leg supporting members vertically move along the supporting structure thanks to at least one linear actuator or a pneumatic or hydraulic cylinder acting between the supporting structure and the leg supporting members. Advantageously the effecting means vertically moving the leg supporting members are controlled by switch means arranged in a position easily reachable by the person under treatment. Advantageously the leg supporting members comprise at least a member for supporting the lower section of the legs between the calf and the internal part of the knee and members supporting and restraining the ankles. Advantageously the apparatus comprises an electronic unit apt to control the effecting means moving the leg supporting members, said electronic unit being able to acquire and store end positions of said leg supporting members and/or other working parameters of said effecting means. From the above described characteristics are clear the advantages related to the use of an apparatus for performing passive lumbar stretching treatments according to the invention which allows the completely autonomous execution of physiotherapy treatments specifically intended to decompress the lumbar/sacral section of the vertebras, whose efficiency is scientifically demonstrated. The fact that the apparatus can be used by a person on his own renders it recommended not only in physiotherapy centres but also in private houses. BRIEF DESCRIPTION OF THE DRAWINGS However, for a better understanding of the above-mentioned advantages and characteristics of the present invention, this will now be described by way of embodiment examples, with reference to the accompanying drawings, in which: FIG. 1 shows a perspective view of an apparatus for performing lumbar stretching treatments according to the invention; FIG. 2 shows a side view of the apparatus of FIG. 1 in a specific working configuration; FIG. 3 shows a side view of the apparatus of FIG. 1 in a different working configuration; FIG. 4 shows a perspective view of a different embodiment of an apparatus for performing lumbar stretching treatments according to the invention; FIG. 5 shows a further embodiment, in partial section, of an apparatus according to the invention; FIG. 6 shows a perspective view of a further embodiment of an apparatus according to the invention; FIG. 7 shows a perspective view of the apparatus of FIG. 6 in a different working configuration. DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1 , it is labelled, as a whole, with 10 , an apparatus for performing passive lumbar stretching treatments comprising a supporting structure, 11 , comprising a vertical column, 12 , and a base, 13 , provided with foots, 14 , and wheels, 15 , apt to stabilize the position of the apparatus on the ground and to allow its easy transfer. Through the end section, 16 , the column 12 is firmly bound to the base 13 by welding, even if it could bound in a detachable way through screw means. A vertical guide member, 18 , is integral to the column, and at the ends of said guide, still integral to the column, there are clamp means, 19 , provided with a hole, where are housed, and supported by radial bearings, the ends of a worm screw, 20 . At the lower end of the worm screw 20 is mounted a gear motor, 21 , bound to a plate, 22 , integral to the column 12 . Between the plate 22 and the clamp 19 there is a thrust bearing, 23 , transferring the force acting upon the worm screw to the plate 22 . The output rod of the gear motor 21 is coaxial to the worm screw 20 and is connected to it so that it put into rotation the worm screw when it is powered. The rotation of the worm screw causes the vertical movement of leg supporting members, 24 , thanks to the fact that these lasts comprise a prismatic element, 25 , provided with a hole where is housed a nut coupled with the worm screw 20 , and it is also provided with a sliding element, not showed as it is of known technique, coupled with the guide 18 . At the sides of the prismatic element 25 are fixed supporting frames, 26 , provided with upholstered means, 27 , where rest the calfs of the person under treatment and further upholstered rollers, 28 , supporting the lower section of the ankles. The upholstered means 27 are longitudinally movable along the frame 26 so that the leg supporting member is made suitable to people of any height. Rods, 29 , bound to the end of the frames 26 mount further upholstered rollers, 30 , adjustable in height thanks to longitudinal grooves made in the rods 29 , said rollers 30 being apt to keep in touch with the upper part of the ankles in order to restrain them. The gear motor 21 can be fed by rechargeable batteries integral to the apparatus or by means of the standard power supply network through a supply cable, 31 , and/or possible power suppliers or transformers. The gear motor can be controlled by switch means, 32 , which can be kept in hand by the person under treatment thanks to the presence of a connecting cable, 33 . As shown in FIGS. 2 and 3 the way of using the apparatus is extremely simple. The person requiring treatments for the passive decompression of the intervertebral disks with reduction of lumbar stenosis lays on his back close to the apparatus and keeping his legs at angle of about 90° with respect to his body rests his legs on the upholstered means 27 of the leg supporting members 24 . After inserting the ankles between the lower rollers 28 and the upper rollers 30 , the legs are restrained and the person is ready to begin the treatment. Pressing the three positions switch 32 the person power on the gear motor 21 which, thanks to the above described mechanism, move the leg supporting member 24 upwards along the column 12 . The lower section of the legs raises so causing moving away the pelvis from the ground and putting under traction the lumbar vertebras. Arrived in the position of FIG. 3 the button of the switch 32 is released, the apparatus stops and the reached position is maintained. You can notice that thanks to the fact that the leg supporting members can be automatically lowered until they are close to the ground, it is possible to take the right initial position at the apparatus even with the legs almost completely extended, letting the apparatus move up the legs. That is particularly useful and advantageous when the lumbar pain is particularly acute during flexion movements. Once passed the amount of time required by the treatment, or when the person wishes to interrupt it, he needs just press the switch 32 in the opposite position in order to move down the leg supporting members 24 to the configuration of FIG. 2 thanks to the reverse side rotation of the gear motor 21 . Obviously, many changes may be carried out, still keeping safe the advantages and the characteristics of the apparatus for performing passive lumbar stretching treatments above described. In FIG. 4 , for instance, is shown an embodiment of the invention in which the apparatus 10 ′ has no base 13 . By the end section 16 and suitable screw means the apparatus can be anywhere fastened, that is directly to the ground or to many types of medic beds normally on the market. In fact, in FIG. 5 is shown a further embodiment of the invention in which the apparatus 10 ″ is integral to a special bed, 40 . The bed has a frame, 41 , provided with foots, 42 , on the frame being fastened the base 13 . The frame 41 is also provided with longitudinal guides, 43 , where move wheels, 44 , integral to a second frame, 45 , of an upholstered lay surface, 46 . Thanks to the guides 43 and the wheels 44 the lay surface is able to longitudinally translate, obviously in a range determined by end elements, in order to render more comfortable the access to the apparatus. The presence of the translatable lay surface is particularly suitable when accessing the apparatus with the leg supporting members completely lowered and then with the legs almost completely extended; in fact when the leg supporting members 24 are moving upwards the lay surface 46 get closer to the column 12 so favouring the natural movement of the legs. On one side of the frame 41 , in a easy to reach position there is the switch 32 ″. Handles 47 , also bound to the frame 41 , are comprised in the apparatus 10 ″. Another embodiment of the apparatus of the invention is labelled with 10 ′″ in FIG. 6 . In this embodiment a parson's back lay surface, 41 ′″, is hinged at one end to the base 13 ′″. The lay surface 41 ′″ is provided with a cushion, 48 , foots, 14 ′″, and lateral handles 47 ′″. The column 12 ′″, provided with carters, 49 , protecting the various electro-mechanical parts, is bound to the base 13 ′″, through a plane, 50 , inclined of about 10° with respect to an horizontal plane, so that the leg supporting members, 24 ′″, move along a line inclined of about 10° with respect to a vertical axis. Thanks to such little inclination during the lifting of the person's legs, the upper section of the legs is carried in a substantially vertical position without the need of translating the person's back towards the column 12 ′″, so further increasing the comfortableness of the apparatus. The frames 26 ′″ are inclined with respect to an horizontal plane, the upholstered members 27 are replaced with upholstered rollers 27 ′″, and the lower upholstered rollers 28 are not present. In that way the lower part of the legs rests on the rollers 27 ′″, acting between the calf and the internal section of the knee, while the upholstered rollers 30 ′″ contrast, pressing against the upper section of the ankle, the aptitude to rotate of the knee's articulation which would take place during the upwards movement of the leg supporting members 24 ′″. In FIG. 7 is shown the apparatus 10 ′″ in a non-use configuration. The lay surface 41 ′″ is rotated of about 90° through an handle, 51 , that can be used also to unlock the lay surface from the in-use position of FIG. 6 , and it is carried in a substantially vertical position where it is automatically locked thanks to proper means located, for instance, in correspondence to the hinged end of the lay surface. Such configuration renders minimum the overall dimensions on the ground of the apparatus and it is particularly suitable when the apparatus is not being used. Furthermore, during the rotation of the lay surface 41 ′″, a roller, 52 , integral to the lay surface itself and freely rotatable around its axis, is moved down towards the ground, enters in touch with the ground and move away from the ground the foots 14 ′″ placed in correspondence to the same end of the base 13 ′″. When the apparatus 10 ′″ has to be transferred to a different location it simply needs to handle it from the handle 51 and, inclining the base 13 ″ to let it be supported only by the roller 52 , to easily pull it that is subject only to the rolling friction of the roller 52 . Certainly many more changes may be carried out to the apparatus of the invention both at the simple versions of FIGS. 1 to 4 and to the more complete versions of FIGS. 5 to 7 ; in particular many parts may be replaced with parts having a similar function. For instance the vertical movement of the leg supporting members 24 may be obtained through the gear motor 21 using different kinematic mechanisms which are apt to obtain substantially vertical movements of the leg supporting members 24 . In different embodiments the movement could be obtained by linear actuators acting between the plate 22 and the prismatic element 25 ; even pneumatic or hydraulic cylinders could be used, changing, in this last option, the energy supply means. In any case the switch means 32 or 32 ″ may be located on a remote control in order to render even more comfortable the use of the apparatus. The supporting structure 11 could be different from the one described and disclosed in the appended figures, both as regards the base 13 and the column 12 . This last, in particular, could also be made of two or more substantially vertical columns properly connected each other and to the base 13 . The column/s, could be shaped ad to directly act as a guide for the leg supporting members 24 , so becoming unnecessary the guide 18 . The leg supporting members 24 could have a structure and could comprise parts even much different from the ones described, remaining the same the function of supporting and restraining the lower section of the legs and maintaining them in a substantially horizontal position. For instance, in cheaper versions of the apparatus, the upholstered means 27 could be replaced with bands horizontally stretched between the sides of the frame 26 , while proper belts could replace the upholstered rollers 28 and 30 . The roller 47 of the embodiment of FIGS. 6 and 7 could be replaced by two or more wheels properly spaced. The effecting means, no matter what kind of propulsive force they use and no matter the kinematic mechanism used, could be controlled and powered by an electronic unit. Thanks to the adoption of the electronic the apparatus could be provided with many further functions such as the possibility of setting various end positions of the leg supporting members 24 , or the possibility of setting their speed, or even the possibility of acquiring and/or storing anthropometric parameters of the user so that specific treatment programmes could be created. These and more modifications may be carried out to the apparatus for performing passive lumbar stretching treatments according to the invention, anyway, within the ambit of protection of the following claims.

An apparatus for performing lumbar stretching treatments comprises a supporting structure where at least one electric motor vertically moves leg supporting members. A person that needs performing lumbar stretching treatments takes the right position at the apparatus and autonomously controls it powering the vertical movement of the leg supporting means which put into traction the lower section of the person's back. The apparatus may also be installed on specific beds having a lay surface horizontally translatable in order to improve the comfortable use of the apparatus.

This is a continuation of application Ser. No. 08/235,712 filed Apr. 29, 1994, now abandoned. FIELD OF THE INVENTION The present invention relates to a liquid developer for electrophotography using an ether compound as a carrier liquid. BACKGROUND OF THE INVENTION Wet development in electrophotography is generally carried out by developing an electrostatic latent image on an electrophotographic photoreceptor with a liquid developer comprising a dispersing medium, usually an aliphatic hydrocarbon, having dispersed therein toner particles mainly comprising a resin and a colorant. The thus formed toner image is transferred to transfer paper and fixed thereon. Where photosensitive paper or film coated with a photoconductive material, such as lead oxide, is used as a photoreceptor, the transfer process may be omitted, that is, the toner image may be fixed on the photoreceptor. Wet development is also often employed as a development system for electrostatic recording consisting of forming an electrostatic latent image on a dielectric film by means of electrodes without using a photoreceptor. The wet development system is primarily based on electrophoresis of fine toner particles of from submicrons to several microns in a carrier liquid having high electrical resistance, such as an aliphatic hydrocarbon. Therefore, this system is characterized by ease of attaining higher resolving power than by dry development system using toner particles of several microns or greater. According to the early literature produced by K. A. Metcalfe (J. Sci. Instrum., Vol. 32, p. 74 (1955) and ibid, vol. 33, p. 194 (1956)), useful pigments for liquid developers include carbon black, magnesium oxide and other various organic or inorganic pigments, and useful carrier liquids include gasoline, kerosine, and carbon tetrachloride. The early patent publications by Metcalfe mention usefulness, as a carrier liquid, of halogenated hydrocarbons (JP-B-35-5511, the term "JP-B" as used herein means an "examined published Japanese patent application"), polysiloxanes (JP-B-36-14872), ligroin, and mixtures of these petroleum hydrocarbons (JP-B-38-22343 and JP-B-43-13519). Patent publications relating to preparation of toners also contain frequent references to a liquid carrier. For example, JP-B-40-19186, JP-B-45-14545, and JP-B-56-9189 describe that aromatic hydrocarbons, such as benzene, toluene and xylene, and aliphatic hydrocarbons, such as n-hexane, isododecane, Isopar G, H, L, M or V (product of Exxon Chemical Corp.), are useful as a carrier liquid, which sometimes serve as a dispersing medium for polymerization. Because most of these carrier liquids proposed to date are organic solvents of high vapor pressure, there are involved such problems that: (1) they vaporize on fixing, etc., tending to cause environmental pollution; (2) they are flammable; and (3) they remain in transfer paper after fixing and give off a solvent smell. In order to solve these problems, it has been proposed to decrease the vapor pressure of a carrier liquid by using a hydrocarbon type petroleum solvent of low vapor pressure or a polymerized hydrocarbon which is solid at ambient temperature (see, for example, JP-A-63-167375, JP-A-2-6965, and JP-A-2-6967, the term "JP-A" as used herein means an "unexamined published Japanese patent application"). However, if the molecular weight of a hydrocarbon is increased in an attempt to reduce the vapor pressure, it generally follows that the viscosity of the carrier liquid increases, tending to adversely affect the rate of development. Besides, the melting point of the carrier liquid also increases to approximately room temperature so that development always needs heating, which will cause reduction in copying speed and necessity of much heat energy in the development and fixing parts in actual development operation, and which will lead to waste of energy, thermal pollution, and deterioration of a developer. Use of a hydrocarbon solution having a resistivity of not less than 10 9 Ω•cm and a dielectric constant of not more than 3.0 as a carrier liquid is taught in JP-A-51-89428. Like this, conventionally proposed carrier liquids are mostly non-polar hydrocarbon solutions having a high resistivity and a low dielectric constant. It is experimentally known in the art that a carrier liquid whose resistivity is lower than an adequate level breaks a latent image on a photoreceptor or causes a bias leak in the development and transfer parts, failing to obtain a satisfactory image. Additionally, developers containing a non-polar carrier liquid having an excessively high resistivity and a low dielectric constant have not always produced satisfactory results with respect to toner charging properties and toner charge stability with time. That is, there has been a tendency that the charge quantity of a toner decreases with time or the proportion of a toner charged to the opposite polarity increases. Hence, under the present situation, a satisfactory carrier liquid for a liquid developer has not yet been developed. SUMMARY OF THE INVENTION An object of the present invention is to provide a carrier liquid for a liquid developer which is odorless, has less danger of fire and is less vaporized from copying machines or printers. Another object of the present invention is to provide a carrier liquid which performs excellent function in charging a toner and stabilizing the charge of the toner. A further object of the present invention is to provide a carrier liquid for a liquid developer which is applicable to high-speed copying in full color as well as in black-and-white. As a result of extensive investigations, the present inventors have found that a carrier liquid selected from an ether compound of a long-chain alcohol (e.g., butanol, pentanol, hexanol, heptanol or octanol) and a diether compound of butylene glycol, pentylene glycol, hexylene glycol, heptylene glycol, octylene glycol or a dimer thereof is practically equal to a conventional carrier liquid in viscosity, much less vaporized on fixing than a conventional carrier liquid, and exhibits excellent charging properties and charge stability. The present invention has been completed based on this finding. The present invention relates to a liquid developer for electrophotography comprising a carrier liquid having dispersed therein toner particles containing a binder resin and a colorant, wherein the carrier liquid contains at least one ether compound selected from compounds represented by formula (I) and compounds represented by formula (II): R.sub.1 --O(C.sub.n H.sub.2n O).sub.x --R.sub.2 (I) R.sub.3 --O--R.sub.4 (II) wherein R 1 , R 2 , R 3 , and R 4 , which may be the same or different, each represent an alkyl group, an alicyclic alkyl group, an aryl group, or an aralkyl group; n represents an integer of from 4 to 8; and x represents 1 or 2. BRIEF DESCRIPTION OF THE DRAWING FIGURE is a circuit diagram of an apparatus for measuring charged toner quantity. DETAILED DESCRIPTION OF THE INVENTION In formulae (I) and (II), groups represented by R 1 , R 2 , R 3 or R 4 include straight-chain or branched alkyl group, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, 1,1-dimethylpropyl, n-hexyl, isohexyl, 2-ethylbutyl, n-heptyl, isoheptyl, n-octyl, iso-octyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl, isodecyl, and 2-ethyloctyl groups; alicyclic alkyl groups, such as cyclopentyl, cyclohexyl, and methylcyclohexyl groups; aryl groups, such as phenyl, tolyl, xylyl, and naphthyl groups; and aralkyl groups, such as benzyl, phenethyl, and phenylpropyl groups. R 1 and R 2 in formula (I) and R 3 and R 4 in formula (II) may be the same or different. An (alicyclic) alkyl group represented R 1 , R 2 , R 3 or R 4 preferably has 4 to 16 carbon atoms. An aryl group represented by R 1 , R 2 , R 3 or R 4 preferably has 8 to 16 carbon atoms. An aralkyl group represented by R 1 , R 2 , R 3 or R 4 preferably has 9 to 16 carbon atoms. The ether compounds of formulae (I) and (II) have appropriate characteristics as a carrier liquid of a liquid developer in terms of insulating properties, viscosity, toner binder dissolving power, and low pour point. They have a markedly reduced vapor pressure as compared with conventional carrier liquids. Additionally, they are odorless. These excellent characteristics are believed to be attributed to the length of the hydrophobic end groups (the kinds and carbon atom numbers of R 1 and R 2 in formula (I) or R 3 and R 4 in formula (II)), the kind and the number of ethereal polar groups in the molecular chain and/or the length of the hydrophobic moiety of a starting diol (the number represented by n in formula (I)). Considerations will hereinafter be given to the relation between the chemical structure of these ether compounds and their performance as a carrier liquid. The length of the hydrophobic group is believed (i) to lessen interaction among polar groups, such as a hydrogen bond thereby decreasing the viscosity, (ii) to raise resistivity up to a level which is experimentally deemed useful, (iii) to increase compatibility to a binder resin, for example, an olefin resin, and (iv) to be correlated with vapor pressure within a certain range. In order to take advantage of these characteristics, it is preferable that the total number of the carbon atoms in R 1 and R 2 is between 4 and 20 or that in R 3 and R 4 is from 8 to 20. If the total carbon atom number of R 1 and R 2 is less than 4 or that of R 3 and R 4 is less than 8, resistivity tends to increase more than necessary, the dissolving power for an olefin resin tends to be reduced, and the vapor pressure tends to increase excessively. If the total carbon atom number of R 1 and R 2 or that of R 3 and R 4 exceeds 20, the viscosity tends to increase more than desired, resulting in reduction in speed of development dependent on electrophoretic force. Further, the melting point increases to approximately room temperature. As previously stated, this means that heat must always be applied to a liquid developer for carrying out development, which is economically disadvantageous and also deteriorates reliability on repetition of heat cycles. The ether group in the molecular chain is considered to have influences on the solidifying point, toner charging properties, and toner binder dissolving power. For example, according as the molecular weight of a straight chain hydrocarbon increases, the solidifying point is elevated up to around room temperature. To the contrary, the ether compound of the present invention, with its molecular weight being substantially equal to that of the above-mentioned straight chain hydrocarbon, shows a reduction of solidifying point. That is, the compound of the present invention serves sufficiently as a carrier liquid even in winter. Compared with hydrocarbons having substantially the same molecular weight, the ether compound of the present invention is superior in function of imparting charges to a toner. That is, the liquid carrier of the present invention accelerates or stabilizes charge exchange with a toner. Further, where a charge control agent, such as a so-called charge director, is added to a liquid developer, the compound of the present invention controls the dispersibility and solubility of the charge control agent thereby improving charge stability as a developer. These effects appear to be produced owing to the polarity of the ether group in the molecular chain. The ether compounds represented by formula (I) will be explained below in detail. General-purpose glycols in industry typically include short-chain glycols, such as ethylene glycol and propylene glycol; and polyoxyalkylene glycols comprising such short-chain glycols as a repeating unit, such as diethylene glycol and dipropylene glycol. Diethers prepared from short-chain glycols are represented by formula (I) wherein n is less than 4. Diethers according to the present invention, prepared from long-chain glycols, are represented by formula (I) wherein n is an integer of from 4 to 8, preferably an integer of from 4 to 6. A diether of a glycol must have a certain total molecular chain length so as to serve as a carrier liquid having a moderately low vapor pressure and satisfactory charging properties and charge stability. If a dialkyl ether having a molecular chain length enough to have such characteristics is prepared from a short-chain glycol, one or both of the hydrophobic ends groups (corresponding to R 1 and R 2 ) must have a considerably long chain. This would follow that the interaction among the hydrophobic groups at one end or both ends increases and the dialkyl ether is liable to have increased viscosity over that prepared from a long-chain glycol. Moreover, a dialkyl ether prepared from a short-chain glycol and having a long-chain hydrophobic group at the terminals thereof and still having high purity is less available due to its high viscosity, tending to increase the cost. Additionally, because of the short distance between oxygen atoms in the molecule, the hydrogen bond between the ethereal oxygen atom and a water molecule becomes strong, easily resulting in moisture absorption in a high temperature and high humidity environment. As a result, electrical conductivity is apt to increase excessively. If the carbon atom number n of a glycol exceeds 8, the diester of such a long-chain glycol, for example a dialkyl ether, has an increased viscosity or a solidifying point increased to room temperature (solidifies at room temperature) irrespective of whether the alkyl group is straight or branched. From all these considerations, the carbon atom number n of the glycol should be between 4 and 8. In other words, the ether compound (I) of the present invention controls the water content in the carrier liquid and prevents excessive increase of conductivity while achieving the purposes of low viscosity and low vaporizability. Should the unit number x in the molecular chain be 3 or more, the whole developer system would have increased hydrophilic properties and, as a result, the carrier liquid would have excessively increased conductivity. To avoid this, the unit number x of the glycol must be 1 or 2. Thus, the liquid developer according to the present invention has a controlled viscosity and, as a result, makes high-speed copying feasible. The ether compounds represented by formula (I) wherein x is 1 include diethers of 1,4-butylene glycol, such as 1,4-butylene glycol diethyl ether, 1,4-butylene glycol dipropyl ether, 1,4-butylene glycol dibutyl ether, 1,4-butylene glycol dipentyl ether, 1,4-butylene glycol dihexyl ether, 1,4-butylene glycol diheptyl ether, 1,4-butylene glycol dioctyl ether, 1,4-butylene glycol dinonyl ether, 1,4-butylene glycol didecyl ether, 1,4-butylene glycol dicyclohexyl ether, 1,4-butylene glycol diphenyl ether, 1,4-butylene glycol ditolyl ether, 1,4-butylene glycol dixylyl ether, 1,4-butylene glycol butyl naphthyl ether, 1,4-butylene glycol dibenzyl ether, 1,4-butylene glycol ethyl butyl ether, 1,4-butylene glycol butyl hexyl ether, and 1,4-butylene glycol butyl 2-ethylhexyl ether, and similar diethers of 1,2-butylene glycol, 1,3-butylene glycol or 2,3-butylene glycol; diethers of 1,5-pentylene glycol, such as 1,5-pentylene glycol diethyl ether, 1,5-pentylene glycol dipropyl ether, 1,5-pentylene glycol dibutyl ether, 1,5-pentylene glycol dipentyl ether, 1,5-pentylene glycol dihexyl ether, 1,5-pentylene glycol diheptyl ether, 1,5-pentylene glycol dioctyl ether, 1,5-pentylene glycol dinonyl ether, 1,5-pentylene glycol didecyl ether, 1,5-pentylene glycol dicyclohexyl ether, 1,5-pentylene glycol diphenyl ether, 1,5-pentylene glycol ditolyl ether, 1,5-pentylene glycol dixylyl ether, 1,5-pentylene glycol butyl naphthyl ether, 1,5-pentylene glycol dibenzyl ether, 1,5-pentylene glycol ethyl butyl ether, 1,5-pentylene glycol butyl hexyl ether, and 1,5-pentylene glycol butyl 2-ethylhexyl ether, and similar diethers of 1,2-pentylene glycol, 1,3-pentylene glycol, 1,4-pentylene glycol, 2,3-pentylene glycol or 2,4-pentylene glycol; diethers of 1,6-hexylene glycol, such as 1,6-hexylene glycol diethyl ether, 1,6-hexylene glycol dipropyl ether, 1,6-hexylene glycol dibutyl ether, 1,6-hexylene glycol dipentyl ether, 1,6-hexylene glycol dihexyl ether, 1,6-hexylene glycol diheptyl ether, 1,6-hexylene glycol dioctyl ether, 1,6-hexylene glycol dinonyl ether, 1,6-hexylene glycol didecyl ether, 1,6-hexylene glycol dicyclohexyl ether, 1,6-hexylene glycol diphenyl ether, 1,6-hexylene glycol ditolyl ether, 1,6-hexylene glycol dixylyl ether, 1,6-hexylene glycol butyl naphthyl ether, 1,6-hexylene glycol dibenzyl ether, 1,6-hexylene glycol ethyl butyl ether, 1,6-hexylene glycol butyl hexyl ether, and 1,6-hexylene glycol butyl 2-ethylhexyl ether, and similar diethers of 1,2-hexylene glycol, 1,3-hexylene glycol, 1,4-hexylene glycol, 1,5-hexylene glycol, 2,3-hexylene glycol, 2,4-hexylene glycol, 2,5-hexylene glycol or 3,4-hexylene glycol; diethers of 1,7-heptylene glycol, such as 1,7-heptylene glycol diethyl ether, 1,7-heptylene glycol dipropyl ether, 1,7-heptylene glycol dibutyl ether, 1,7-heptylene glycol dicyclohexyl ether, 1,7-heptylene glycol diphenyl ether, 1,7-heptylene glycol dibenzyl ether, and 1,7-heptylene glycol ethyl butyl ether, and similar diethers of 1,2-heptylene glycol, 1,3-heptylene glycol, 1,4-heptylene glycol, 1,5-heptylene glycol, 1,6-heptylene glycol, 2,3-heptylene glycol, 2,4-heptylene glycol, 2,5-heptylene glycol, 2,6-heptylene glycol, 3,4-heptylene glycol or 3,5-heptylene glycol; and diethers of 1,8-octylene glycol, such as 1,8-octylene glycol diethyl ether, 1,8-octylene glycol dipropyl ether, 1,8-octylene glycol dibutyl ether, 1,8-octylene glycol dicyclohexyl ether, 1,8-octylene glycol diphenyl ether, 1,8-octylene glycol dibenzyl ether, and 1,8-octylene glycol ethyl butyl ether, and similar diethers of 1,2-octylene glycol, 1,3-octylene glycol, 1,4-octylene glycol, 1,5-octylene glycol, 1,6-octylene glycol, 1,7-octylene glycol, 2,3-octylene glycol, 2,4-octylene glycol, 2,5-octylene glycol, 2,6-octylene glycol, 2,7-octylene glycol, 3,4-octylene glycol, 3,5-octylene glycol, 3,6-octylene glycol or 4,5-octylene glycol. The ether compounds of formula (I) wherein x is 2, i.e., diethers of diglycols, include diethers of di-1,4-butylene glycol, such as di-1,4-butylene glycol diethyl ether, di-1,4-butylene glycol dipropyl ether, di-1,4-butylene glycol dibutyl ether, di-1,4-butylene glycol dipentyl ether, di-1,4-butylene glycol dihexyl ether, di-1,4-butylene glycol diheptyl ether, di-1,4-butylene glycol dioctyl ether, di-1,4-butylene glycol dinonyl ether, di-1,4-butylene glycol didecyl ether, di-1,4-glycol dicyclohexyl ether, di-1,4-butylene glycol diphenyl ether, di-1,4-butylene glycol ditolyl ether, di-1,4-butylene glycol dixylyl ether, di-1,4-butylene glycol butyl naphthyl ether, di-1,4-butylene glycol dibenzyl ether, di-1,4-butylene glycol ethyl butyl ether, di-1,4-butylene glycol butyl hexyl ether, and di-1,4-butylene glycol butyl 2-ethylhexyl ether; and similar diethers of di-1,2-butylene glycol, di-1,3-butylene glycol, di-2,3-butylene glycol, di-1,2-pentylene glycol, di-1,3-pentylene glycol, di-1,4-pentylene glycol, di-1,5-pentylene glycol, di-2,3-pentylene glycol, di-2,4-pentylene glycol, di-1,5-hexylene glycol, di-1,6-hexylene glycol, di-1,7-heptylene glycol or di-1,8-octylene glycol. The ether compounds represented by formula (II) will be explained below in detail. Since the compounds (II) have only one ethereal polar group in the molecule, they are structurally close to conventionally employed paraffin solvents and have substantially the same characteristics as a carrier liquid, such as electrical resistivity, as those of conventional carrier liquids. Accordingly, the compounds (II) can be used in accordance with the known techniques applied to conventional carrier liquids and, besides, meet both the demands for low viscosity and low vaporizability. Thus, use of the ether compounds (II) as a carrier liquid provides a liquid developer having a reduced viscosity and thereby suitability to high-speed copying. The ether compounds (II) include alkyl ethers, alicyclic alkyl ethers, aryl ethers, and aralkyl ethers. The alkyl ethers include simple dialkyl ethers, such as di-n-butyl ether, di-n-pentyl ether, di-n-hexyl ether, di-n-heptyl ether, di-n-octyl ether, di-n-nonyl ether, and di-n-decyl ether, and mixed ethers, such as n-propyl n-pentyl ether, n-propyl n-hexyl ether, n-propyl n-heptyl ether, n-propyl n-octyl ether, n-butyl n-pentyl ether, n-butyl n-hexyl ether, n-butyl n-heptyl ether, n-butyl n-octyl ether, n-butyl n-nonyl ether, n-butyl n-decyl ether, n-butyl n-undecyl ether, n-butyl n-dodecyl ether, n-pentyl n-hexyl ether, n-pentyl n-heptyl ether, n-pentyl n-octyl ether, n-pentyl n-nonyl ether, n-pentyl n-decyl ether, n-pentyl n-undecyl ether, n-pentyl n-dodecyl ether, n-hexyl n-heptyl ether, n-hexyl n-octyl ether, n-hexyl n-nonyl ether, n-hexyl n-decyl ether, n-hexyl n-undecyl ether, n-hexyl n-dodecyl ether, n-heptyl n-octyl ether, n-heptyl n-nonyl ether, n-heptyl n-decyl ether, n-heptyl n-undecyl ether, n-heptyl n-dodecyl ether, n-octyl n-nonyl ether, n-octyl n-decyl ether, n-octyl n-undecyl ether, n-octyl n-dodecyl ether, n-nonyl n-decyl ether, and n-nonyl n-undecyl ether. Additionally, the above-enumerated alkyl ethers with the n-alkyl group thereof being replaced with its structural isomer, i.e., an iso-, sec- or t-alkyl group, are also useful. These alkyl ethers are particularly effective to suppress increases in viscosity and solidifying point as have occurred with paraffin oils or isoparaffin oils. The alicyclic alkyl ethers include dicyclopentyl ether, dicyclohexyl ether, dimethylcyclohexyl ether, n-butyl cyclopentyl ether, n-hexyl cyclopentyl ether, n-octyl cyclopentyl ether, n-decyl cyclopentyl ether, n-butyl cyclohexyl ether, n-hexyl cyclohexyl ether, n-octyl cyclohexyl ether, n-decyl cyclohexyl ether, cyclopentyl cyclohexyl ether, cyclohexyl methylcyclohexyl ether, and cyclopentyl methylcyclohexyl ether. In these alicyclic alkyl ethers, the n-alkyl group may be replaced with its structural isomer, i.e., an iso-, sec- or t-alkyl group. The alicyclic alkyl ethers are particularly effective to improve dissolving power for a charge control agent to thereby stabilize the charge imparting characteristics. The aryl ethers and aralkyl ethers include diphenyl ether, ditolyl ether, dibenzyl ether, diphenethyl ether, diphenylpropyl ether, n-butyl phenyl ether, n-hexyl phenyl ether, n-octyl phenyl ether, n-butyl tolyl ether, n-hexyl tolyl ether, n-butyl benzyl ether, ethyl naphthyl ether, n-butyl naphthyl ether, and n-pentyl naphthyl ether. In these ethers, the n-alkyl group may be replaced with its structural isomer, i.e., an iso-, sec- or t-alkyl group. The aryl or aralkyl ethers are particularly effective to control the evaporation loss of a carrier liquid from a copying machine and also effective to improve charge imparting properties. The ether compounds (I) and (II) according to the present invention may be used either individually or in combination of two or more thereof. They may also be used in combination with conventional carrier liquids. Suitable conventional carrier liquids with which the ether compounds of the present invention may be combined include branched aliphatic hydrocarbons, such as Isopar G, H, L, M or V; straight chain aliphatic hydrocarbons, such as Norpar 14, 15 or 16 (produced by Exxon); waxy hydrocarbons having a relatively high molecular weight, such as n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and n-nonadecane; halogenated hydrocarbons of the above-mentioned hydrocarbons, such as fluorocarbons; silicon oils; and modified silicon compounds. The conventional carrier liquid may be used in an amount of 5 to 95 wt % of the ether compound of the present invention. When used in combination with a paraffin hydrocarbon having a relatively high molecular weight, the ether compound of the present invention reduces the solidifying point of the paraffin hydrocarbon from around room temperature to a range causing no practical problem. Further, the ether compound is effective to improve charging characteristics of a paraffin hydrocarbon. When combined with other carrier liquids, the proportion of the ether compound of the present invention in the total carrier liquid is suitably 5 to 100 wt %, more preferably 20 to 100 wt %. If it is less than 5% by weight, the effect of reducing a solidifying point of an aliphatic hydrocarbon having a high molecular weight or the effect of reducing the vapor pressure of a paraffin oil having a low molecular weight would be insufficient. The effect on improvement of charging characteristics would also be insufficient. The binder resin which can be used in toner particles includes polyolefins, such as polyethylene and polypropylene. Particularly preferred binder resins are ethylene copolymers having a polar group, such as copolymers of ethylene and an α,β-ethylenically unsaturated acid (e.g., acrylic acid or methacrylic acid) or an alkyl esther thereof or ionomers prepared by subjecting these ethylene copolymers to ionic crosslinking. For details of synthesis of copolymers of this type, refer to U.S. Pat. No. 3,264,272 to Ree. In addition, homopolymers of styrene or a styrene derivative, such as o-, m- or p-methylstyrene, α-methylstyrene, p-ethylstyrene or 2,4-dimethylstyrene, and styrene copolymers comprising styrene and an acrylic monomer or other copolymerizable monomers are also useful as a binder resin. The acrylic monomer in the above-mentioned styrene copolymers includes acrylic or methacrylic esters, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-chloroethyl (meth)acrylate, and phenyl (meth)acrylate; α-methylene monocarboxylic acid esters, such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; ammonium methacrylate; and betaine compounds thereof. Other useful binder resins include homopolymers of the above-mentioned (meth)acrylic acids or esters thereof; homopolymers or copolymers of perfluorooctyl (meth)acrylate, vinyltoluenesulfonic acid or a sodium salt thereof, or a vinylpyridine compound or a pyridinium salt thereof; copolymers of a diene, e.g., butadiene or isoprene, and a vinyl monomer; and dimeric acid-based polyamide resins. Additionally, polyester resins, polyurethane resins, and the like may also be used either individually or in combination with the above-described resins. The colorants which can be dispersed in the binder resin include organic or inorganic pigments or dyes. Examples of suitable colorants are C.I. Pigment Red 48:1, C.I. Pigment Red 57:1, C.I. Pigment Red 122, C.I. Pigment Red 17, C.I. Pigment Yellow 97, C.I. Pigment Yellow 12, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:3, lamp black (C.I. No. 77266), Rose Bengal (C.I. No. 45432), carbon black, nigrosine (C.I. No. 50415B), and mixtures thereof. In addition, various metal oxides, such as silica, aluminum oxide, magnetite, ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, and magnesium oxide, and mixtures thereof may be employed. The colorant is used in a sufficient amount enough to form a visible image with sufficient density. Such an amount usually ranges from 1 to 100 parts by weight per 100 parts by weight of the binder resin, while depending on the size of toner particles and the proportion of charged toner particles. The proportion of the toner particles of the present invention in the total carrier liquid is preferably 0.1 to 5 wt %, more preferably 0.5 to 2 wt %. Toner particles and a liquid developer can be prepared by any of known methods, such as those described in the literature of Metcalfe supra, JP-A-58-2851, JP-A-58-129438, JP-A-58-152258, and U.S. Pat. No. 4,794,651 to B. Landa, et al. For example, a toner can be prepared by a method comprising dispersing and kneading a binder resin, a colorant and a carrier liquid in an appropriate apparatus at a temperature at which the resin can be plasticized, the carrier liquid is prevented from boiling, and the resin and/or the colorant is prevented from decomposing. More specifically, a resin and a colorant are heat-melted in a carrier liquid by means of a planetary mixer, a kneader, etc., and the molten mixture is cooled while stirring to solidify and precipitate toner particles by taking advantage of the temperature dependence of the degree of resin's melting in a solvent. There is another method for toner preparation, in which a resin, a colorant, and a carrier liquid are dispersed and kneaded in a vibration mill equipped with a granular medium for dispersion and kneading, such as an attritor or a ball mill, heated at an appropriate temperature, e.g., 80° to 160° C. Suitable granular media include stainless steel, carbon steel, alumina, zirconia and silica. In carrying out this method, the starting materials, having been sufficiently fluidized, are dispersed in the mill with the aid of the granular medium, and the carrier liquid is cooled to precipitate the resin as containing the colorant. It is important to keep the granular medium in a dispersed state to give shear and/or impact to toner particles thereby reducing the toner particle size. The thus prepared toner particles preferably have a volume average particle size of smaller than 10 μm, and more preferably 5 μm or smaller, as determined with a centrifugal particle size distribution measuring apparatus. If desired, the particles may have a shape with a fibrous surface, i.e., a shape with numeral fibers, curling whiskers, tentacles, etc. A still another method for preparing a liquid developer comprises melting a weighed quantity of a resin by heating, adding a weighed quantity of a colorant to the molten resin at a prescribed mixing ratio, dispersing the mixture, cooling, grinding the solidified mixture to fine particles by means of a grinding machine, such as a jet mill, a hammer mill, a turbo mill, etc., and dispersing the resulting toner particles in a carrier liquid. Toner particles may also be prepared by polymerization (suspension polymerization, emulsion polymerization or dispersion polymerization), coacervation, melt dispersion, or emulsion coagulation. The resulting toner particles are then dispersed in a carrier liquid. If desired, a charge control agent may be incorporated into a carrier liquid or toner particles for the purpose of ensuring uniformity and stability of polarity and quantity of charges. Charge control agents conventionally used in a liquid developer, such as lecithin, Basic Barium Petronate, Basic Sodium Petronate or Basic Calcium Petronate (produced by Witoco Chemical Corp.), oil-soluble petroleum sulfonates, alkylsuccinimides, dioctyl sodium sulfosuccinate, and metallic soaps, e.g., zirconium octanoate, can be used in the present invention. Additionally, ionic or nonionic surfactants, metallized dyes, quaternary ammonium salts, organic or inorganic salts, such as organic borates, and block or graft copolymers having a lipophilic part and a hydrophilic part can also be used as a charge control agent. If desired, the liquid developer of the present invention may further contain fine polymer particles, inorganic particles or any other additives for improving various physical properties. The present invention will now be illustrated in greater detail with reference to Examples, but the present invention should not be construed as being limited thereto. In the Examples, all the parts, percents, and ratios are by weight unless otherwise indicated. EXAMPLE 1 ______________________________________Ethylene (89%)-methacrylic acid (11%) 40 partscopolymer ("Nucrel N699", produced byE. I. du Pont de Nemours & Co., Inc.)Copper phthalocyanine pigment ("Cyanine 4 partsBlue 4933M" produced by DainichiseikaColour & Chemicals Mfg. Co., Ltd.)Norpar 15 100 parts______________________________________ The above components were charged in a stainless steel-made beaker and heated to 120° C. on an oil bath for 1 hour while stirring to prepare a uniform, completely molten mixture. The mixture was gradually cooled to room temperature with stirring, and 100 parts of Norpar 15 was added thereto. As the temperature of the system decreased, pigment-containing particles having a particle diameter of from 10 to 20 μm began to precipitate. A 100 g portion of the precipitated toner was put in an attritor ("Model 01" manufactured by Mitsui Miike K. K.) and ground with steel balls having a diameter of 0.8 mm at 300 rpm while monitoring the volume average particle size with a centrifugal particle size distribution meter ("SA-CP4L" manufactured by Shimadzu Corporation). Grinding was continued until the volume average particle size was reduced to 2.5 μm (for about 20 hours). The resulting concentrated toner having a toner concentration of 18% was used as a base toner. Twenty parts of the base toner were diluted with 160 parts of pentylene glycol dibutyl ether to a toner concentration of 2%, followed by thoroughly stirring. To the mixture was added 0.1 part, per part of the toner, of Basic Barium Petronate (hereinafter abbreviated as BBP) as a charge director, followed by thoroughly stirring to prepare a liquid developer. EXAMPLE 2 Twenty parts of the base toner obtained in Example 1 were diluted with 160 parts of hexylene glycol ethyl butyl ether to a toner concentration of 2%. After thorough stirring, Basic Sodium Petronate (hereinafter abbreviated as BSP) was added thereto as a charge director in the same proportion as used in Example 1, and the mixture was thoroughly stirred to prepare a liquid developer. EXAMPLE 3 ______________________________________Polyester resin (prepared by polymerization 85 partsof terephthalic acid and ethylene oxide-addedbisphenol A; weight average molecular weight:12000; acid value: 5; softening point: 110° C.)Magenta pigment ("Carmine 6B" produced by 15 partsDainichiseika Colour & Chemicals Mfg. Co., Ltd.)______________________________________ The above components were kneaded in an extruder, ground in a jet mill, and classified by an air classifier to prepare a toner having an average particle size of 3 μm. The resulting toner was dispersed in butylene glycol dioctyl ether in a concentration of 2%, and Basic Calcium Petronate (hereinafter abbreviated as BCP) was added thereto as a charge director in the same proportion as used in Example 1, followed by thoroughly stirring to prepare a liquid developer. EXAMPLE 4 A concentrated toner was prepared in the same manner as in Example 1, except for using "Pigment Yellow 17" (produced by Dainichiseika Colour & Chemicals Mfg. Co., Ltd.) as a colorant, and the resulting base toner was diluted with pentylene glycol dibutyl ether in the same manner as in Example 1. To the mixture was added dioctyl sodium sulfosuccinate as a charge director in the same proportion as in Example 1, followed by thoroughly stirring to obtain a liquid developer. EXAMPLE 5 ______________________________________Ethylene (85%)-methacrylic acid (10%)- 40 partsoctyl methacrylate (5%) copolymerPigment Yellow 17 4 partsNorpar 15 100 parts______________________________________ A base toner was prepared from the above components in the same manner as in Example 1. Twenty parts of the base toner (toner concentration: 18%) were diluted with 160 parts of hexylene glycol dibutyl ether to a toner concentration of 2%. After thorough stirring, a charge director was added thereto in the same manner as in Example 1 to prepare a liquid developer. EXAMPLE 6 A liquid developer was prepared in the same manner as in Example 1, except for using carbon black ("Regal 330" produced by Cabot G. L. Inc.) as a colorant. The toner had a particle size of 2.5 μm. COMPARATIVE EXAMPLE 1 A liquid developer was prepared in the same manner as in Example 1, except for diluting the base toner with Isopar L to a toner concentration of 2%. COMPARATIVE EXAMPLE 2 The base toner prepared in Example 1 was diluted with Isopar H to a toner concentration of 2%. Soybean lecithin was added thereto as a charge director in the same proportion as in Example 1, and the mixture was thoroughly stirred to prepare a liquid developer. The composition of the liquid developers prepared in Examples 1 to 5 and Comparative Examples 1 to 2 is tabulated in Table 1 below. Each of the liquid carriers used in Examples and Comparative Examples and liquid developers prepared in these Examples was evaluated in accordance with the following test methods. 1) Rate of Evaporation of Carrier Liquid Three grams of the carrier liquid used in each liquid developer was put in a glass petri dish (opening diameter: 50 mm), and the dish was left on a hot plate kept at 40° C. for a prescribed period of time (x hours), and the evaporation loss (g) was measured with a precision weighing machine. The rate of evaporation per unit area per unit time was obtained from equation: Rate of evaporation (g/m.sup.2 •h)=Evaporation loss (g) after x hours/opening area (m.sup.2)•x (hr) 2) Quantities of Charged Toner and Oppositely Charged Toner Three milliliters of the liquid developer was filled in a 1 mm gap between parallel disc electrodes (diameter: 10 cm; electrode area: about 78 cm 2 ), and a voltage of 1000 V was applied thereto for 1 second to provide an electrical field of +10 4 V/cm. The electrode on which the toner deposited was dried in a vacuum drier at 120° C. for 2 hours to completely remove the carrier liquid. The quantity of the normally charged toner was obtained from the difference in weight of the electrode before and after toner deposition. The same procedure was followed, except for changing the polarity of the voltage applied, to determine the quantity of the toner charged to the opposite polarity. The circuit diagram of the apparatus used in the above measurement is shown in FIGURE. In FIGURE, 1 shows a pulse oscillator, 2 shows a high-voltage powder supply apparatus, 3 shows an electrode, 4 shows an ammeter and 5 shows a current waveform analyzer. 3) Solidifying point of Carrier Liquid The carrier liquid was allowed to stand at 20° C., 0° C., -10° C. or -20° C., and the temperature at which the sample solidified was taken as a solidifying point for the sake of simplicity. The results of theses tests are shown in Table 2 below. TABLE 1__________________________________________________________________________Toner CompositionExample BinderNo. Resin Pigment Charge Director Carrier Liquid__________________________________________________________________________Example 1 ethylene- copper BBP pentylene glycol methacrylic phthalocyanine dibutyl ether acid copolymerExample 2 ethylene- copper BSP hexylene glycol methacrylic phthalocyanine ethyl butyl ether acid copolymerExample 3 polyester resin Carmine 6B BCP butylene glycol dioctyl etherExample 4 ethylene- Pigment Yellow 17 dioctyl sodium pentylene glycol methacrylic sulfosuccinate dibutyl ether acid copolymerExample 5 ethylene- " BBP hexylene glycol methacrylic dibutyl ether acid- octyl methacrylate copolymerExample 6 ethylene- carbon black " pentylene glycol methacrylic dibutyl ether acid copolymerCompar. ethylene- copper " Isopar LExample 1 methacrylic phthalocyanine acid copolymerCompar. ethylene- Carmine 6B soybean lecithin Isopar HExample 2 methacrylic acid copolymer__________________________________________________________________________ TABLE 2__________________________________________________________________________ Normally Oppositely Charged Toner Quantity Charged Toner Quantity Rate of Immediately 7 Days Immediately 7 Days Evaporation of Toner after after after afterExample Carrier Liquid Charging Preparation Preparation Preparation PreparationNo. (g/m.sup.2 · hr) Polarity (mg) (mg) (mg) (mg)__________________________________________________________________________Example 1 4.0 negative 21.3 22.0 0.0 0.0Example 2 3.8 negative 20.5 21.0 0.1 0.1Example 3 2.4 negative 21.0 21.5 0.0 0.1Example 4 4.0 positive 25.8 26.0 0.0 0.1Example 5 3.8 negative 20.7 21.0 0.0 0.0Example 6 4.0 negative 21.5 22.0 0.0 0.0Compar. 115 negative 10.5 10.1 1.9 3.4Example 1Compar. 132 negative 10.1 9.8 2.0 3.1Example 2__________________________________________________________________________ As is apparent from Table 2, the carrier liquids used in Examples 1 to 6 have a rate of evaporation greatly reduced to about 1/29 to 1/55 of that of conventional carrier liquids as used in Comparative Examples 1 and 2. The toners of the developers of Examples 1, 2, 3, 5 and 6 exhibit satisfactory negative chargeability with substantially no chargeability to opposite polarity, and their charging characteristics were stable over 7 days from the preparation. The toner of the developer of Example 4 exhibits satisfactory positive chargeability with substantially no chargeability to opposite polarity, and the charging characteristics were stable with time. To the contrary, the charged toner quantity of the developers of Comparative Examples 1 and 2 was about a half of those in Examples 1 to 6 or even lower and, moreover, the proportion of the toner quantity charged to opposite polarity was considerably high. EXAMPLE 7 A liquid developer having a toner concentration of 2% was prepared in the same manner as in Example 1, except for diluting the base toner with a 1:1 mixture of pentylene glycol dibutyl ether and Norpar 15. EXAMPLE 8 A liquid developer having a toner concentration of 2% was prepared in the same manner as in Example 1, except for diluting the base toner with a 1:1 mixture of hexylene glycol dibutyl ether and Isopar L. COMPARATIVE EXAMPLE 3 A liquid developer having a toner concentration of 2% was prepared in the same manner as in Example 1, except for diluting the base toner with Norpar 15. The rate of evaporation and solidifying point of the carrier liquid used in Examples 7 and 8 and Comparative Example 3 were measured in the same manner as described above. The results obtained are shown in Table 3 below. TABLE 3______________________________________ Rate of SolidifyingExample Evaporation PointNo. Carrier Liquid (g/m.sup.2 · hr) (°C.)______________________________________Example 7 pentylene glycol 4.2 0 to -10 dibutyl ether: Norpar 15 = 1:1Example 8 hexylene glycol 8.8 <-20 dibutyl ether: Isopar L = 1:1Compar. Norpar 15 4.5 0Example 3______________________________________ As is apparent from Table 3, the carrier liquid of Example 7 has a rate of evaporation of 4.2 g/m 2 •hr and a solidifying point between 0° and -10° C., both of which are satisfactory for practical use. The rate of evaporation of the carrier liquid of Example 8 is 8.8 g/m 2 •hr, which is considerably lower than that of Isopar L alone. To the contrary, the solidifying point of the carrier liquid of Comparative Example 3 is 0° C., which means that the developer becomes waxy in winter, needing to be heated on use. The liquid developer prepared in Example 2 was used for actual image formation by a copying machine "FX-5030" (manufactured by Fuji Xerox Co., Ltd.) wherein its blackcolor developing unit portion was modified for application of a liquid developer. As a result, satisfactory copies of high resolving power were obtained. When copies were taken continuously, the 100th copy was equal in quality to those obtained in the initial stage. EXAMPLE 9 ______________________________________Ethylene (89%)-methacrylic acid (11%) 40 partscopolymer (Nucrel N699)Copper phthalocyanine pigment 4 parts(Cyanine Blue 4933M)Norpar 15 100 parts______________________________________ The above components were charged in a stainless steel-made beaker and heated to 120° C. on an oil bath for 1 hour while stirring to prepare a uniform, completely molten mixture. The mixture was gradually cooled to room temperature with stirring, and 100 parts of Norpar 15 was added thereto. As the temperature of the system decreased, pigment-containing particles having a particle diameter of from 10 to 20 μm began to precipitate. A 100 g portion of the precipitated toner was put in an attritor (Model 01) and ground with steel balls having a diameter of 0.8 mm at 300 rpm while monitoring the volume average particle size with a centrifugal particle size distribution meter (SA-CP4L). Grinding was continued until the volume average particle size was reduced to 2.5 μm (for about 20 hours). The resulting concentrated toner having a toner concentration of 18% was used as a base toner. Twenty parts of the base toner were diluted with parts of diheptyl ether to a toner concentration of 2%, followed by thoroughly stirring. To the mixture was added 0.1 part, per part of the toner, of BBP as a charge director, followed by thoroughly stirring to prepare a liquid developer. EXAMPLE 10 Twenty parts of the base toner obtained in Example 9 were diluted with 160 parts of dioctyl ether to a toner concentration of 2%. BSP was added thereto as a charge director in the same proportion as used in Example 9, and the mixture was thoroughly stirred to prepare a liquid developer. EXAMPLE 11 ______________________________________Polyester resin (prepared by polymerization 85 partsof terephthalic acid and ethylene oxide-addedbisphenol A; weight average molecular weight:12000; acid value: 5; softening point: 110° C.)Magenta pigment ("Carmine 6B") 15 parts______________________________________ The above components were kneaded in an extruder, ground in a jet mill, and classified by an air classifier to prepare a toner having an average particle size of 3 μm. The resulting toner was dispersed in diphenyl ether in a concentration of 2%, and BCP was added thereto as a charge director in the same proportion as in Example 9, followed by thoroughly stirring to prepare a liquid developer. EXAMPLE 12 A concentrated toner was prepared in the same manner as in Example 9, except for using Pigment Yellow 17 as a colorant, and the resulting base toner was diluted with diheptyl ether in the same manner as in Example 9. To the mixture was added dioctyl sodium sulfosuccinate as a charge director in the same proportion as in Example 9, followed by thoroughly stirring to obtain a liquid developer. EXAMPLE 13 ______________________________________Ethylene (85%)-methacrylic acid (10%)- 40 partsoctyl methacrylate (5%) copolymerPigment Yellow 17 4 partsNorpar 15 100 parts______________________________________ A base toner was prepared from the above components in the same manner as in Example 9. Twenty parts of the base toner (toner concentration: 18%) were diluted with 160 parts of butyl 2-ethylhexyl ether to a toner concentration of 2%, and the mixture was thoroughly stirred. A charge director was added thereto in the same manner as in Example 9 to prepare a liquid developer. EXAMPLE 14 A liquid developer was prepared in the same manner as in Example 9, except for using carbon black (Regal 330) as a colorant. The toner had a particle size of 2.5 μm. COMPARATIVE EXAMPLE 4 A liquid developer was prepared in the same manner as in Example 9, except for diluting the base toner with Isopar L to a toner concentration of 2%. COMPARATIVE EXAMPLE 5 The base toner prepared in Example 9 was diluted with Isopar H to a toner concentration of 2%. Soybean lecithin was added thereto as a charge director in the same proportion as in Example 9, and the mixture was thoroughly stirred to prepare a liquid developer. The composition of the liquid developers prepared in Examples 9 to 14 and Comparative Examples 4 to 5 is tabulated in Table 4 below. Each of the liquid carriers and developers was evaluated in the same manner as in Example 1. The results obtained are shown in Table 5 below. TABLE 4__________________________________________________________________________Toner CompositionExample BinderNo. Resin Pigment Director Carrier Liquid__________________________________________________________________________Example 9 ethylene- copper BBP diheptyl ether methacrylic phthalocyanine acid copolymerExample 10 ethylene- copper BSP dioctyl ether methacrylic phthalocyanine acid copolymerExample 11 polyester resin Carmine 6B BCP diphenyl etherExample 12 ethylene- Pigment Yellow 17 dioctyl sodium diheptyl ether methacrylic sulfosuccinate acid copolymerExample 13 ethylene- " BBP butyl 2-ethyl- methacrylic hexyl ether acid-octyl methacrylate copolymerExample 14 ethylene- carbon black " diheptyl ether methacrylic acid copolymerCompar. ethylene- copper " Isopar LExample 4 methacrylic phthalocyanine acid copolymerCompar. ethylene- copper soybean lecithin Isopar HExample 5 methacrylic phthalocyanine acid copolymer__________________________________________________________________________ TABLE 5__________________________________________________________________________ Normally Oppositely Charged Toner Quantity Charged Toner Quantity Rate of Immediately 7 Days Immediately 7 Days Evaporation of Toner after after after afterExample Carrier Liquid Charging Preparation Preparation Preparation PreparationNo. (g/m.sup.2 · hr) Polarity (mg) (mg) (mg) (mg)__________________________________________________________________________Example 9 1.92 negative 25.5 25.0 0.1 0.0Example 10 0.51 negative 24.3 25.0 0.0 0.1Example 11 0.43 negative 32.0 31.2 0.1 0.1Example 12 1.92 negative 23.9 24.2 0.1 0.1Example 13 2.30 positive 33.0 32.8 0.1 0.1Example 14 1.92 negative 26.0 26.1 0.0 0.1Compar. 89.2 negative 10.5 10.1 1.9 3.4Example 4Compar. 118 negative 10.1 9.8 2.0 3.1Example 5__________________________________________________________________________ As is apparent from Table 5, the carrier liquids used in Examples 9 to 14 have a rate of evaporation greatly reduced to about 1/39 to 1/274 of that of conventional carrier liquids as used in Comparative Examples 4 and 5. The toners of the developers of Examples 9 to 12 and 14 each exhibit satisfactory negative chargeability with substantially no chargeability to opposite polarity, and their charging characteristics were stable over 7 days from the preparation. The toner of the developer of Example 13 exhibits satisfactory positive chargeability with substantially no chargeability to opposite polarity, and the charging characteristics were stable with time. To the contrary, the charged toner quantity of the developers of Comparative Examples 4 and 5 was about a half of those in Examples 9 to 14 or even lower and, moreover, the proportion of the toner quantity charged to opposite polarity was considerably high. EXAMPLE 15 A liquid developer having a toner concentration of 2% was prepared in the same manner as in Example 9, except for diluting the base toner with a 1:1 mixture of dioctyl ether and Norpar 15. EXAMPLE 16 A liquid developer having a toner concentration of 2% was prepared in the same manner as in Example 9, except for diluting the base toner with a 1:1 mixture of diphenyl ether and Isopar L. COMPARATIVE EXAMPLE 6 A liquid developer having a toner concentration of 2% was prepared in the same manner as in Example 9, except for diluting the base toner with Norpar 15. The rate of evaporation and solidifying point of the carrier liquid used in Examples 15 and 16 and Comparative Example 6 were measured in the same manner as described above. The results obtained are shown in Table 6 below. TABLE 6______________________________________ Rate of SolidifyingExample Evaporation PointNo. Carrier Liquid (g/m.sup.2 · hr) (°C.)______________________________________Example 15 dioctyl glycol 0.82 0 to -10 ether:Norpar 15 = 1:1Example 16 diphenyl ether: 1.03 <-20 Isopar L = 1:1Compar. Norpar 15 2.5 0Example 6______________________________________ As is apparent from Table 6, the carrier liquid of Example 15 has a rate of evaporation of 0.82 g/m 2 •hr and a solidifying point between 0° and -10° C., both of which are satisfactory for practical use. The rate of evaporation of the carrier liquid of Example 16 is 1.03 g/m 2 •hr, which is considerably lower than that of Isopar L alone. To the contrary, the solidifying point of the carrier liquid of Comparative Example 6 is 0° C., which means that the developer becomes waxy in winter, needing to be heated on use. The liquid developer prepared in Example 10 was used for actual image formation in the same manner as described above. As a result, satisfactory copies of high resolving power were obtained. When copies were taken continuously, the 100th copy was equal in quality to those obtained in the initial stage. As discussed above, the characteristic of the present invention consists in use of the ether compound represented by formula (I) or (II) as a carrier liquid of a liquid developer. The carrier liquids according to the present invention have adequate characteristics in terms of insulating properties, viscosity, dissolving power for a toner binder, and pour point. Further, they have markedly lower solidifying point and vapor pressure than those of conventional carrier liquids. As a result, they do not need heating even in winter, and they have a reduced evaporation loss and less danger of fire. Additionally, the carrier liquids of the present invention exhibit satisfactory charging properties to impart charges to toner particles in a stable manner with time. Thus, the liquid developer according to the present invention is very satisfactory for practical use. While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

A liquid developer for electrophotography comprising a carrier liquid having dispersed therein toner particles containing a binder resin and a colorant, wherein said carrier liquid contains at least one ether compound selected from compounds represented by formula (I) and compounds represented by formula (II): R.sub.1 --O(C.sub.n H.sub.2n O).sub.x --R.sub.2 (I) R.sub.3 --O--R.sub.4 (II) wherein R 1 , R 2 , R 3 , and R 4 , which may be the same or different, each represent an alkyl group, an alicyclic alkyl group, an aryl group, or an aralkyl group; n represents an integer of from 4 to 8; and x represents 1 or 2. The developer requires no heating even in winter and is less vaporized and less dangerous owing to the low solidifying point and low vapor pressure of the carrier liquid. The developer stably exhibits satisfactory charging properties. The developer is suited to high-speed copying.

RELATED APPLICATIONS [0001] This application relates and claims benefit of U.S. Provisional Application Ser. No. 60/578,467 filed on Jun. 8, 2004, all of which is incorporated by reference in its entirety. FIELD OF INVENTION [0002] The present invention is directed towards a process of synthesis of cyclic phosphonic acid diesters from 1,3-diols. More specifically, the invention relates to an improved process wherein diastereoselectivity is increased during coupling a 1-arylpropane-1,3-diol with an activated phosphonic acid. BACKGROUND OF THE INVENTION [0003] The following description of the background of the invention is provided to aid in understanding the invention, but is not admitted to be, or to describe, prior art to the invention. All publications are incorporated by reference in their entirety. [0004] Compounds containing phosphonic acids and their salts are highly charged at physiological pH and therefore frequently exhibit poor oral bioavailability, poor cell penetration and limited tissue distribution (e.g., CNS). In addition, these acids are also commonly associated with several other properties that hinder their use as drugs, including short plasma half-life due to rapid renal clearance, as well as toxicities (e.g., renal, gastrointestinal, etc.) (e.g., Bijsterbosch et al., Antimicrob. Agents Chemother. 42(5): 1146-50(1998)). [0005] Phosphonic acid ester prodrugs can be used to improve the oral bioavailability, cell penetration and tissue distribution of drugs containing a phosphonic acid moiety. The most commonly used prodrug class is the acyloxyalky ester, which was first applied to phosphate and phosphonate compounds in 1983 by Farquhar et al., J. Pharm. Sci. 72: 324 (1983). This strategy has proven successful in the delivery of phosphates and phosphonates into cells and in the oral absorption of phosphates, phosphonate's and phosphinic acids. For example, the bis(pivoyloxymethyl) prodrug of the antiviral phosphonate, 9-(2-phosphonylmethoxyethyl)adenine (PMEA), has been studied clinically for the treatment of CMV infection and the bis(pivaloyloxymethyl) prodrug of the squalene synthetase inhibitor, BMS188494 has been evaluated as a treatment of hypercholesterolemia and associated cardiovascular diseases. The marketed antihypertensive, fosinopril, is a phosphinic acid angiotensin converting enzyme inhibitor that requires the use of an isobutryloxyethyl group for oral absorption. A close variant of the acyloxyalkyl ester strategy is the use of alkoxycarbonyloxyalkyl groups as prodrugs. These prodrugs are reported to enhance oral bioavailability. [0006] Other examples of suitable phosphonate prodrugs include proester classes exemplified by Krise et al. ( Adv. Drug Del. Rev. 19: 287 (1996)); and Biller and Magnin (U.S. Pat. No. 5,157,027). [0007] Cyclic phosphonate esters have also been shown to decrease serum lipids and treat atherosclerosis (U.S. Pat. No. 5,962,440). Other examples of phosphonate esters are exemplified by Prisbe et al. ( J. Med. Chem. 29: 671 (1986)); and Ozoe et al. ( Bioorg. Med. Chem. 6: 73 (1998). SUMMARY OF THE INVENTION [0008] The present invention is directed towards a Lewis acid catalysis process for the synthesis of a cyclic phosphonic acid diester from a 1,3-diol and an activated phosphonic acid. In one aspect, methods are described that enable diastereoselective preparation of these products. In another aspect, the methods can also be used to prepare chiral substituted cyclic phosphonic acid (or phosphonate) diesters. [0009] One aspect of the invention concerns a method of preparing a cyclic phosphonic acid diester via reacting a chiral 1,3-diol and an activated phosphonic acid in the presence of a Lewis acid. In a further aspect, the Lewis acid is added to the chiral 1,3-diol and the diol-Lewis acid complex is added to the activated phosphonic acid. [0010] In an additional aspect, the ratio of cis- to trans-diastereomers formed is greater than or equal to 3:1. [0011] Also provided are methods where the Lewis acid contains an element selected from the group consisting of titanium, tin, aluminum, zinc, boron, magnesium, samarium, bismuth, iron, mercury, copper, silver and cobalt. In an additional aspect, the Lewis acid contains an element selected from the group consisting of titanium, boron, aluminum, tin, and samarium. In a further aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical. In another aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical, where the inorganic radical is selected from the group consisting of chloride, iodide, bromide, and fluoride. In a further aspect, the Lewis acid is selected from TiCl 4 , BF 3 , SnCl 4 , SmI 2 , and AlCl 3 . An additional aspect the Lewis acid is TiCl 4 . In a further aspect the Lewis acid is Ti(O—(C 1 -C 4 )alkyl) 4 . [0012] Also provided are methods where the activated phosphonic acid is phosphonic acid halide, phosphonic acid anhydride, or phosphonic acid carbonate. In another aspect, the activated phosphonic acid is phosphonic acid halide. In a further aspect, the phosphonic acid halide is phosphonyl chloride. [0013] In another aspect, the method provides for adding a base selected from tertiary alkyl amines, N-containing heterocyclic aromatic bases, and non-nucleophilic inorganic bases. In a further aspect, the base is triethylamine, tri(n-butyl)amine, pyridine, quinoline or diisopropylethylamine. [0014] In one aspect, the temperature for the reaction is −78° C. and 60° C. In another aspect, the temperature is between −20° C. and 50° C. In a further aspect, the temperature is between 15° C. and 42° C. [0015] In one aspect, the reaction is carried out by adding 0.01 to 5 equivalents of said Lewis acid to 1.0 equivalent of said chiral 1,3-diol. In a further aspect, 0.5 to 2.0 equivalents of said Lewis acid is added. [0016] One aspect of the invention concerns the method for the preparation of compounds of Formula I: wherein: V is selected from group consisting of phenyl, allyl, alkynyl, and monocyclic heteroaryl, all optionally substituted with 1-4 substituents; R 1 is selected from the group consisting of hydrogen, optionally substituted aryl, optionally substituted heteroaryl, or R 1 is a group of the formula Ar 1 -G-Ar 2 , wherein Ar 1 and Ar 2 are aryl groups optionally substituted by lower alkyl, lower alkoxy, halogen, hydroxy, cyano, and amino, and G is —O—, —S—, —S(═O)—, —S(═O) 2 —, —CH 2 —, —CF 2 —, —CHF—, —C(O)—, —CH(OH)—, —NH—, and —N(C 1 -C 4 alkyl)-; alk 1 and alk 2 are the same or different and are each optionally-substituted lower alkylene; Y is selected from the group consisting of —O—, —S—, —NR 2 —, —C(O)—, —C(O)NR 2 , and —NR 2 C(O)—; W and W′ are independently selected from the group consisting of H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted monocyclic aryl, and optionally substituted monocyclic heteroaryl; Z is selected from the group consisting of halogen, —CN, —COR 3 , —CONR 4 2 , —CO 2 R 3 , —CHR 2 OC(O)R 3 , —CHR 2 OC(S)R 3 , —CHR 2 OC(O)SR 3 , —CHR 2 OCO 2 R 3 , —OR 3 , —SR 3 , —R 2 , —NR 3 2 , —OCOR 3 , —OCO 2 R 3 , —SCOR 3 , —SCO 2 R 3 , —(CH 2 ) p —OR 4 , and —(CH 2 ) p —SR 4 ; R 2 is hydrogen or lower alkyl; R 3 is alkyl; R 4 is alkyl or acyl; p is 2 or 3; r is 0 or 1; and s is 0 or 1. [0031] In a further aspect, the hydroxy groups present in the formula Ar 1 -G-Ar 2 may be protected. [0032] In another aspect, said 1-(aryl)-1,3-propane diol is added to the Lewis acid and then the diol-Lewis acid complex is added to R 1 (alk 1 ) r Y s (alk 2 )P(O)Cl 2 in the presence of said base. [0033] In an additional aspect the method of preparation for compounds of Formula I provides for an increased ratio of cis to trans diastereomers. In an additional aspect, the ratio of cis- to trans-diastereomers formed is greater than or equal to 3:1. [0034] Also provided are methods where the Lewis acid contains an element selected from the group consisting of titanium, tin, aluminum, zinc, boron, magnesium, samarium, bismuth, iron, mercury, copper, silver and cobalt. In an additional aspect, the Lewis acid contains an element selected from the group consisting of titanium, boron, aluminum, tin, and samarium. In a further aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical. In another aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical, where the inorganic radical is selected from the group consisting of chloride, iodide, bromide, and fluoride. In a further aspect, the Lewis Acid is selected from TiCl 4 , BF 3 , SnCl 4 , SmI 2 , and AlCl 3 . In an additional aspect, the Lewis acid is TiCl 4 . In a further aspect, the Lewis acid is Ti(O—(C 1 -C 4 )alkyl) 4 . [0035] In another aspect, the method provides for adding a base selected from tertiary alkyl amines, N-containing heterocyclic aromatic bases, and non-nucleophilic inorganic bases. In a further aspect the base is triethylamine, tri(n-butyl)amine, pyridine, quinoline or diisopropylethylamine. [0036] In one aspect, the temperature for the reaction is −78° C. and 60° C. In another aspect the temperature is between −20° C. and 50° C. In a further aspect, the temperature is between 15° C. and 42° C. [0037] In one aspect, the reaction is carried out by adding 0.01 to 5 equivalents of said Lewis acid to 1.0 equivalent of said chiral 1,3-diol. In a further aspect, 0.5 to 2.0 equivalents of said Lewis acid is added. [0038] Some of the compounds of Formula I have asymmetric centers where the stereochemistry is unspecified and the diastereomeric mixtures of these compounds are included as well as the individual stereoisomers when referring to a compound of Formula I generally. [0039] In another aspect, the invention relates to a method for the preparation of compounds of Formula II: wherein, V is selected from group consisting of aryl, and monocyclic heteroaryl, all optionally substituted with 1-4 substituents; W and W′ are independently selected from the group consisting of H, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted monocyclic aryl, and optionally substituted monocyclic heteroaryl; Z is selected from the group consisting of halogen, —CN, —COR 3 , —CONR 4 2 , —CO 2 R 3 , —CHR 2 OC(O)R 3 , —CHR 2 OC(S)R 3 , —CHR 2 OC(O)SR 3 , —CHR 2 OCO 2 R 3 , —OR 3 , —SR 3 , —R 2 , —NR 2 , —OCOR 3 , —OCO 2 R 3 , —SCOR 3 , —SCO 2 R 3 , —(CH 2 ) p —OR 4 , and —(CH 2 ) p —SR 4 ; T is selected from the group consisting of H and lower alkyl; R 2 is hydrogen or lower alkyl; R 3 is alkyl; R 4 is alkyl or acyl; p is 2 or 3; r is 0 or 1; and s is 0 or 1; R 5 is a monovalent amine protecting group, and R 6 is hydrogen; or, R 5 and R 6 taken together are a divalent amine protecting group. [0053] In another aspect, the method of preparing a compound of Formula II includes combining a 1-(V)-1,3-propane diol with a compound of Formula III in the presence of a Lewis acid: [0054] In an additional aspect the method of preparation for compounds of Formula II provides for an increased ratio of cis to trans diastereomers. In an additional aspect, the ratio of cis- to trans-diastereomers formed is greater than or equal to 3:1. [0055] Also provided are methods where the Lewis acid contains an element selected from the group consisting of titanium, tin, aluminum, zinc, boron, magnesium, samarium, bismuth, iron, mercury, copper, silver and cobalt. In an additional aspect, the Lewis acid contains an element selected from the group consisting of titanium, boron, aluminum, tin, and samarium. In a further aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical. In another aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical, where the inorganic radical is selected from the group consisting of chloride, iodide, bromide, and fluoride. In a further aspect, the Lewis Acid is selected from TiCl 4 , BF 3 , SnCl 4 , SmI 2 , and AlCl 3 . An additional aspect the Lewis acid is TiCl 4 . In a further aspect, the Lewis acid is Ti(O—(C 1 -C 4 )alkyl) 4 . [0056] In another aspect, the method provides for adding a base selected from tertiary alkyl amines, N-containing heterocyclic aromatic bases, and non-nucleophilic inorganic bases. In a further aspect the base is triethylamine, tri(n-butyl)amine, pyridine, quinoline or diisopropylethylamine. [0057] In one aspect, the temperature for the reaction is −78° C. and 60° C. In another aspect the temperature is between −20° C. and 50° C. In a further aspect, the temperature is between 15° C. and 42° C. [0058] In one aspect, the reaction is carried out by adding 0.01 to 5 equivalents of said Lewis acid to 1.0 equivalent of said chiral 1,3-diol. In a further aspect, 0.5 to 2.0 equivalents of said Lewis acid is added. [0059] Some of the compounds of Formula II have asymmetric centers where the stereochemistry is unspecified and the diastereomeric mixtures of these compounds are included as well as the individual stereoisomers when referring to a compound of Formula II generally. [0060] The present invention provides a method for the preparation of compounds of Formula IV: wherein R 5 is tert-butyloxycarbonyl, benzyloxycarbonyl, trifluoroacetyl or benzyl; and R 6 is hydrogen; or, R 5 and R 6 taken together are phthalimidoyl, phenylmethylidene, dimethylaminomethylidene and diethylaminomethylidene; and T is selected from the group consisting of H and lower alkyl. [0064] An additional aspect provides a method for the preparation of compounds of Formula IV: wherein R 5 is tert-butyloxycarbonyl, benzyloxycarbonyl, trifluoroacetyl or benzyl; and R 6 is hydrogen; or, R 5 and R 6 taken together are phthalimidoyl, phenylmethylidene, dimethylaminomethylidene and diethylaminomethylidene; T is selected from the group consisting of H and lower alkyl; comprising: combining (R)-1-(3-chlorophenyl)-1,3-propanediol with a compound of Formula III in the presence of a Lewis acid. [0070] In a further aspect of the preparation of compounds of Formula IV said (R)-1-(3-chlorophenyl)-1,3-propanediol is added to the Lewis acid and then the diol-Lewis acid complex is added to the compound of Formula III. [0071] In an additional aspect, the method of preparation for compounds of Formula IV provides for an increased ratio of cis to trans diastereomers. In an additional aspect, the ratio of cis- to trans-diastereomers formed is greater than or equal to 3:1. [0072] Also provided are methods where the Lewis acid contains an element selected from the group consisting of titanium, tin, aluminum, zinc, boron, magnesium, samarium, bismuth, iron, mercury, copper, silver and cobalt. In an additional aspect, the Lewis acid contains an element selected from the group consisting of titanium, boron, aluminum, tin, and samarium. A further aspect the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical. In another aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical, where the inorganic radical is selected from the group consisting of chloride, iodide, bromide, and fluoride. In a further aspect, the Lewis Acid is selected from TiCl 4 , BF 3 , SnCl 4 , SmI 2 , and AlCl 3 . In an additional aspect, the Lewis acid is TiCl 4 . In a further aspect, the Lewis acid is Ti(O—(C 1 -C 4 )alkyl) 4 . [0073] In another aspect, the method provides for adding a base selected from tertiary alkyl amines, N-containing heterocyclic aromatic bases, and non-nucleophilic inorganic bases. In a further aspect, the base is triethylamine, tri(n-butyl)amine, pyridine, quinoline or diisopropylethylamine. [0074] In one aspect, the temperature for the reaction is −78° C. and 60° C. In another aspect the temperature is between −20° C. and 50° C. In a further aspect, the temperature is between 15° C. and 42° C. [0075] In one aspect, the reaction is carried out by adding 0.01 to 5 equivalents of said Lewis acid to 1.0 equivalent of said chiral 1,3-diol. In a further aspect, 0.5 to 2.0 equivalents of said Lewis acid is added. [0076] Some of the compounds of Formula IV have asymmetric centers where the stereochemistry is unspecified and the diastereomeric mixtures of these compounds are included as well as the individual stereoisomers when referring to a compound of Formula IV generally. [0077] A further aspect the invention provides a method for the preparation of compounds of Formula V: wherein R is lower alkyl and T is selected from the group consisting of H and lower alkyl. In one aspect (R)-1-(3-chlorophenyl)-1,3-propanediol is combined with a compound of Formula VI in the presence of a Lewis acid: [0079] In a further aspect of the preparation of compounds of Formula IV said (R)-1-(3-chlorophenyl)-1,3-propanediol is added to the Lewis acid and then the diol-Lewis acid complex is added to the compound of Formula VI. [0080] In an additional aspect the method of preparation for compounds of Formula V provides for an increased ratio of cis to trans diastereomers. In an additional aspect, the ratio of cis- to trans-diastereomers formed is greater than or equal to 3:1. [0081] Also provided are methods where the Lewis acid contains an element selected from the group consisting of titanium, tin, aluminum, zinc, boron, magnesium, samarium, bismuth, iron, mercury, copper, silver and cobalt. In an additional aspect, the Lewis acid contains an element selected from the group consisting of titanium, boron, aluminum, tin, and samarium. In a further aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical. In another aspect, the Lewis acid contains a group independently selected from alkoxy, alkyl, aryl, or an inorganic radical, where the inorganic radical is selected from the group consisting of chloride, iodide, bromide, and fluoride. In a further aspect, the Lewis Acid is selected from TiCl 4 , BF 3 , SnCl 4 , SmI 2 , and AlCl 3 . In an additional aspect, the Lewis acid is TiCl 4 . In a further aspect, the Lewis acid is Ti(O—(C 1 -C 4 )alkyl) 4 . [0082] In another aspect, the method provides for adding a base selected from tertiary alkyl amines, N-containing heterocyclic aromatic bases, and non-nucleophilic inorganic bases. In a further aspect, the base is triethylamine, tri(n-butyl)amine, pyridine, quinoline or diisopropylethylamine. [0083] In one aspect, the temperature for the reaction is −78° C. and 60° C. In another aspect, the temperature is between −20° C. and 50° C. In a further aspect the temperature is between 15° C. and 42° C. [0084] In one aspect, the reaction is carried out by adding 0.01 to 5 equivalents of said Lewis acid to 1.0 equivalent of said chiral 1,3-diol. In a further aspect, 0.5 to 2.0 equivalents of said Lewis acid is added. [0085] Some of the compounds of Formula V have asymmetric centers where the stereochemistry is unspecified and the diastereomeric mixtures of these compounds are included as well as the individual stereoisomers when referring to a compound of Formula V generally. [0086] Additionally, methods and salt forms are described that enable isolation and purification of the desired isomer. [0000] Definitions [0087] In accordance with the present invention and as used herein, the following terms are defined with the following meanings, unless explicitly stated otherwise. [0088] The term “hexanes” refers to commercially available HPLC reagent solutions which contains approximately 95% hexane, methylcyclopropane, and methylpentane. [0089] The term “dialkyl” refers to a compound containing two alkyl groups. The term “alkyl” refers to saturated aliphatic groups including straight-chain, branched chain and cyclic groups. Suitable alkyl groups include methyl, ethyl, isopropyl, and cyclopropyl. [0090] The term “alkylene” refers to a divalent straight chain, branched chain or cyclic saturated aliphatic group. In one aspect the alkylene group contains up to and including 10 atoms. In another aspect the alkylene chain contains up to and including 6 atoms. In a further aspect the alkylene groups contains up to and including 4 atoms. The alkylene group can be either straight, branched, unsaturated, or cyclic. The alkylene may be optionally substituted with 1-3 substituents. [0091] The term “aryl” refers to aromatic groups which have 5-14 ring atoms and at least one ring having a conjugated pi electron system and includes carbocyclic aryl, heterocyclic aryl and biaryl groups, all of which may be optionally substituted. [0092] Heterocyclic aryl or heteroaryl groups are groups which have 5-14 ring atoms wherein 1 to 4 of the ring atoms are heteroatoms with the remainder of the ring atoms being carbon atoms. Suitable heteroatoms include oxygen, sulfur, nitrogen, and selenium. Suitable heteroaryl groups include furanyl, thienyl, pyridyl, pyrrolyl, N-lower alkyl pyrrolyl, pyridyl-N-oxide, pyrimidyl, pyrazinyl, imidazolyl, adeninyl, thyminyl, cytosinyl, guaninyl, uracilyl, and the like, all optionally substituted. [0093] The term “monocyclic aryl” refers to aromatic groups which have 5-6 ring atoms and includes carbocyclic aryl and heterocyclic aryl. Suitable aryl groups include phenyl, furanyl, pyridyl, and thienyl. Aryl groups may be substituted. [0094] The term “monocyclic heteroaryl” refers to aromatic groups which have 5-6 ring atoms wherein 1 to 4 heteroatoms are ring atoms in the aromatic ring and the remainder of the ring atoms being carbon atoms. Suitable heteroatoms include oxygen, sulfur, and nitrogen. [0095] The term monovalent nitrogen protecting group refers to a protecting group that is attached to nitrogen by a single bond. Examples include but are not limited to tert-butyloxycarbonyl, benzyloxycarbonyl, trifluoroacetyl and benzyl. [0096] The term divalent nitrogen protecting group refers to a protecting group that is attached to nitrogen either by two single bonds or by a double bond. Examples include but are not limited to phthalimidoyl, phenylmethylidene, dimethylaminomethylidene and diethylaminomethylidene. [0097] The term “optionally substituted” or “substituted” includes aryl groups substituted by one to four substituents, independently selected from lower alkyl, lower aryl, and halogens. In one aspect these substituents are selected from the group consisting of halogens. [0098] The term ‘chiral’ refers to an object or molecule that is not superimposable upon its mirror image. [0099] The term ‘diastereoselective’ refers to a reaction in which two or more diastereomers may be formed wherein unequal amounts of the diastereomers are obtained. If two diastereomers are formed, typically the ratio of diastereomers is at least 2:1. [0100] The term ‘Lewis acid’ refers to any species that can accept a pair of electrons and form a coordinate covalent bond. [0101] The term “cis” stereochemistry refers to the relationship of the V group and M group positions on the six-membered ring. V and M are said to be located cis to each other if they lie on the same side of the plane. The formula below shows a cis stereochemistry. Another cis stereochemistry would have V and M pointing above the plane. The formula below shows this cis stereochemistry. [0102] The term “trans” stereochemistry refers to the relationship of the V group and M group positions on the six-membered ring. V and M are said to be located trans to each other if they lie on opposite side of the plane. The formula below shows a trans stereochemistry. Another trans stereochemistry would have M pointing above the plane and V pointing below the plane. The formula below shows this trans stereochemistry. [0103] The term “N6-substituted” refers to the substitution at the amine attached at the 6-position of a purine ring system. N6- is generally substituted with an amine protecting group. Examples include the dialkylaminomethylene group, BOC, CBz, trityl as well as divalent groups like phthalimidoyl. [0104] The terms “N,N-dialkylaminomethyleneimine,” “N,N-dialkylaminomethylene” and “N,N-dialkylaminomethylidene” refer to the functional group or substitution of the following structure wherein R groups include but are not limited to C1-C4 acyclic, alkyl, C5-C6 cyclic alkyl, benzyl, phenethyl, or R groups together form piperdine, morpholine, and pyrrolidine. [0106] The term “nitrogen protecting group” refers to R group and includes but is not limited to BOC, CBz, trityl, N,N-dialkylaminomethylidene, phthalimidoyl, or other monovalent and divalent groups. [0107] The term “phosphonic acid halide” refers to a phosphonic acid wherein the two OH groups have been replaced by halogen atoms. The formula below shows this structure [0108] The term “phosphonic acid anhyride” refers to a compound that is formed by combining two moles of phosphonic acid with the removal of one mole of water. The formula below shows an example of this structure [0109] The term “phosphonic acid carbonate” refers to a phosphonic acid wherein one OH groups has been replaced by a carbonate group. The formula below shows an example of this structure [0110] The term “percent enantiomeric excess (% ee)” refers to optical purity. It is obtained by using the following formula: [ R ] - [ S ] [ R ] + [ S ] × 100 = % ⁢   ⁢ R - % ⁢   ⁢ S where [R] is the amount of the R isomer and [S] is the amount of the S isomer. This formula provides the % ee when R is the dominant isomer. [0112] The term “d.e.” refers to diastereomeric excess. It is obtained by using the following formula: [ cis ] - [ trans ] [ cis ] + [ trans ] × 100 = % ⁢   [ cis ] - % ⁢   [ trans ] [0113] The term “diastereoisomer” refers to compounds with two or more asymmetric centers having the same substituent groups and undergoing the same types of chemical reactions wherein the diasteroismers have different physical properties, have substituent groups which occupy different relative positions in space, and have different biological properties. [0114] The term “racemic” refers to a compound or mixture that is composed of equal amounts of dextrorotatory and levorotatory forms of the same compound and is not optically active. [0115] The term “enantiomer” refers to either of a pair of chemical compounds whose molecular structures have a mirror-image relationship to each other. [0116] The term “halogen” refers to chloride, bromide, iodide, or fluoride. [0117] The term “prodrug” as used herein refers to any M compound that when administered to a biological system generates a biologically active compound as a result of spontaneous chemical reaction(s), enzyme catalyzed chemical reaction(s), and/or metabolic chemical reaction(s), or a combination of each. Standard prodrugs are formed using groups attached to functionality, e.g., HO—, HS—, HOOC—, R 2 N—, associated with the drug that cleave in vivo. Standard prodrugs include but are not limited to carboxylate esters where the group is alkyl, aryl, aralkyl, acyloxyalkyl, alkoxycarbonyloxyalkyl as well as esters of hydroxyl, thiol and amines where the group attached is an acyl group, an alkoxycarbonyl, aminocarbonyl, phosphate or sulfate. The groups illustrated are exemplary, not exhaustive, and one skilled in the art could prepare other known varieties of prodrugs. Such prodrugs of the compounds of formula A, fall within the scope of the present invention. Prodrugs must undergo some form of a chemical transformation to produce the compound that is biologically active or is a precursor of the biologically active compound. In some cases, the prodrug is biologically active, usually less than the drug itself, and serves to improve drug efficacy or safety through improved oral bioavailability, pharmacodynamic half-life, etc. The biologically active compounds include, for example, anticancer agents, and antiviral agents. [0118] The term “cyclic phosphate ester of 1,3-propanediol”, “cyclic phosphate diester of 1,3-propanediol”, “2 oxo 2λ 5 [1,3,2]dioxaphosphorinane”, “2-oxo-[1,3,2]-dioxaphosphorinane”, or “dioxaphosphorinane” refers to the following: [0119] The term “enhancing” refers to increasing or improving a specific property. [0120] The term “enriching” refers to increasing the quantity of a specific isomer produced by a reaction. [0121] The term “non-nucleophilic inorganic base” refers to an inorganic base that has low potential to react with electrophiles. Examples of non-nucleophilic inorganic bases include sodium bicarbonate, sodium carbonate, and potassium carbonate. [0122] The term “activated phosphonic acid” refers to a phosphonic acid wherein the two OH groups have been replaced by leaving groups, such as halogen atoms. [0123] The following well known chemicals are referred to in the specification and the claims. Abbreviations and common names are also provided. BOC; tert-butoxycarbonyl group CBz; benzyl carbamate Trityl; triphenylmethyl group CH 2 Cl 2 ; dichloromethane or methylene chloride DCM; dichloromethane (−)-DIP-Cl; (−)-β-chlorodiisopinocampheylborane DMAP; 4-dimethylaminopyridine DMF; dimethylformamide HCl; hydrochloric acid KI; potassium iodide MgSO 4 ; magnesium sulfate MTBE; t-butyl methyl ether NaCl; sodium chloride NaOH; sodium hydroxide PyBOP; benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate TEA; triethylamine THF; tetrahydrofuran TMSCI; chlorotrimethylsilane TMEDA; tetramethylethlenediamine EDTA; ethylenediaminetetraacetic acid. [0144] The following well known drugs are referred to in the specification and the claims. Abbreviations and common names are also provided. PMEA; 9-(2-phosphonylmethoxyethyl)adenine (Adefovir) (R)-PMPA; (R)-9-(2-phosphonylmethoxypropyl)adenine (Tenofovir) (R)-PMPDAP; (R)-9-(2-phosphonylmethoxypropyl)-2,-6-diaminopurine FPMPDAP; 9-[(2RS)-3-fluoro-2-phosphonylmethoxypropyl]-2,6-diaminopurine FPMGP; 9-[(2RS)-3-fluoro-2-phosphonylmethoxypropyl]guanine (S)-HPMPDAP; 9-=[2S]-3-hydroxy-2-phosphonylmethoxylpropyl]-2,6-diaminopurine PMEG; 9-(2-phosphonylmethoxyethyl)guanine PMEI; 2-phosphonylmethoxyethyl-6-oxopurine PMEMAP; 9-(2-phosphonylmethoxyethyl) 2 -aminopurine PMET; 2-phosphonylmethoxyethyl-thymine DETAILED DESCRIPTION OF THE INVENTION [0155] This invention is directed to the discovery that the utilization of Lewis acid catalysis in the coupling process during the synthesis of cyclic 1,3-propanyl esters of phosphonyl compounds enhanced the ratio of diastereomers of the resultant product. In one aspect the invention is directed towards the utilization of Lewis acid catalysis in the coupling process during the synthesis of cyclic 1-aryl-1,3-propanyl esters of phosphonyl compounds. Compounds synthesized by the process of the present invention are directed towards cyclic esters of phosphonic acids as shown in the following formula: [0156] Cyclic ester prodrugs of phosphonic acids have been demonstrated to be useful in improving the oral bioavailability of drugs containing a phosphonic acid moiety, and in increasing the concentration of the active drug in the liver (U.S. Pat. No. 6,312,662). The cyclic 1,3-propanyl-1-aryl phosphonate cyclic esters of PMEA and related analogs having cis relative stereochemistry have been shown to be able to treat diseases of the liver (U.S. PreGrant Published Application 2003/0229225 A1). These compounds enhance the oral delivery and/or prolong the pharmacodynamic half-life of PMEA and like analogs. In addition, the compounds achieve targeted delivery of PMEA to the liver and increase the therapeutic index of the drug. [0157] The aforementioned prodrugs have been made in a modestly stereoselective manner by coupling a chiral 1,3-diol with a phosphonic acid dichloridate at low temperature (U.S. PreGrant Published Application 2003/0225277 A1). The dichloridate of PMEA is readily prepared using standard chlorination conditions. The coupling reaction with the dichloridate at low temperature was complicated by the poor solubility of the dichloridate. It was found that by adding a protected form of the dichloridate to the diol at low temperatures a diastereoselectivity of 50% could be achieved. [0158] Lewis acids have been used to improve the diastereoselectivity of chemical reactions. For example, titanium tetrachloride has been used to enhance the diastereoselectivity of enolate aldol reactions (Evans et. al., J. Am. Chem. Soc. 112: 8215 (1990); Evans et. al., J. Am. Chem. Soc. 113: 1047 (1991)). It has been proposed that a six membered transition state is the controlling factor of the enhanced diastereoselectivity. It has also been shown that titanium tetrachloride can be used as a catalyst for phosphoryl transfer (Jones et. al., Org. Lett. 4: 3671 (2002)). However, Lewis acids have not been reported to improve the diastereoselectivity of formation of cyclic phosphonic esters; this application describes such an invention. [0159] During the coupling reaction functional groups on the R as shown in the above Formula W, such as amines and hydroxyl groups, may be protected with a variety of amine protecting groups. An example of use of the dialkylamine methylidene group (N,N-dialkylaminomethylene and N,N-dialkylaminomethylidene) is shown below with the nitrogen attached to the carbon labeled 6 protected in the structure below. [0160] The process for the synthesis of cyclic 1,3-propanyl esters with the desired stereochemistry is via a convergent synthetic sequence. The final resultant compound contained two stereocenters, (1) the methine carbon which is identified as C4′ in the steroisomeric structures and (2) the phosphorus of the cyclic phosphonate ring. [0161] The phosphorus chirality was the result of the diastereoselective coupling of the parent phosphonic acid and the chiral diol. The desired cis isomer, wherein cis refers to the isomeric relationship between the phosphorus-carbon bond and the carbon-aryl bond of the cyclic phosphonate ring, was isolated via a selective crystallization of the acid salt. [0000] Compounds Prepared by the Invention [0000] 1. Synthesis of N6-Protected PMEA-Dichloridate: [0162] Chlorination of PMEA is achieved using oxalyl chloride and N,N-diethylformamide to give N6 protected-PMEA-dichloridate. N,N-dialkylformamide used in the chlorination step not only forms a Vilsmeyer chlorinating agent, but also protects the NH 2 group at the 6 position. 2. Coupling of Phosphonic Dichloridate and Chiral Diol: [0163] 2.1 Effect of Dichloridate Addition Order and Temperature. [0164] Earlier work (U.S. Pat. No. 2,003,225277 A1) had shown that the coupling of the protected phosphonic acid dichloridate and diol can be accomplished by low temperature addition to the diol in the presence of base. This led to a modest d.e. of 50% and required conducting the reaction at low temperatures. [0165] Unexpectedly and surprisingly, the inventors observed improved d.e.'s when this low temperature coupling was done in the presence of a Lewis acid. Changes were made to the order of addition of the reagents (see Table 1). When the solution of the diol and base was added to a mixture of the dichloridate and Lewis acid, the results were similar to those obtained above. When a complex of the diol and Lewis acid was added to the dichloridate, there was a further increase in both the d.e. and overall yield of the desired product. These results show that high diastereoselectivity is possible independent of addition order but that in one aspect the diol and Lewis acid are added to the dichloridate for high diastereoselectivity. [0166] Another aspect found was that using this procedure, the coupling reaction no longer has to be performed at low temperatures. TABLE 1 EFFECT OF SOLUTION COMPONENTS, TEMPERATURE AND ADDITION ORDER Temp Cis:Trans Entry Base Equiv. (° C.) Addition Area % d.e. 1 Bu 3 N 4.8 −70 to −65 dichloridate to (diol + base + TiCl 4 )  59:13 64 4 Et 3 N 4.8 −70 to −65 dichloridate to (diol + base + TiCl 4 )  73:15 66 5 Et 3 N 3.1 10 to 15 dichloridate to (diol + TiCl 4 + base) 38:7 69 6 Et 3 N 4.0 0 to 10 dichloridate to (diol + TiCl 4 + base)  22:1 87 2 Bu 3 N 4.8 0 to 10 (diol + base) to (dichoridate + TiCl 4 )  58:11 68 3 Et 3 N 4.8 0 to 10 (diol + base) to (dichoridate + TiCl 4 )  60:14 62 7 Et 3 N 4.0 20 to 25 (diol + TiCl 4 + base) to dichloridate 76:1 97 8 Et 3 N 4.0 Reflux (diol + TiCl 4 + base) to dichloridate 76:6 85 9 Hunig 4.0 18 to 22 (diol + TiCl 4 + base) to dichloridate 73:4 90 10 Et 3 N 6.0 17 to 19 (diol + TiCl 4 + base) to dichloridate 73:3 92 11 Et 3 N 9.0 17 to 22 (diol + TiCl 4 + base) to dichloridate 74:2 95 3. Isolation of Cyclic Phosphonic Ester: [0167] The reaction mixture from the coupling reaction was quenched with methanol and partitioned with water. The acidic aqueous phase containing the product was extracted several times with chloroform. The combined organic layers were dried and concentrated to an oil, affording the N6 protected form of the cyclic phosphonic ester. [0168] An alternative method of isolation consists of addition of a base (such as triethylamine) to the reaction mixture, resulting in precipitation of salts derived from the Lewis acid. Filtration of the precipitated material is facilitated by the use of a filter aid (e.g. diatomaceous earth, Fuller's earth, Montmorillonite clay), after which the filtrate containing the product is concentrated or further manipulated in the usual way (washing with water, extraction of the product into aqueous acid, back-extraction with an organic solvent, etc.). [0169] A further aspect of workup involves use of a chelating agent to remove materials derived from the Lewis acid. In one aspect the chelating agent could be a bifunctional organic compound (e.g., TMEDA, tartaric acid, EDTA) that renders the salts derived from the Lewis acid water-soluble, and hence removable by extraction. In another aspect the chelating agent could also be a functionalized solid support (e.g., a polymeric resin containing amine or carboxylic acid functional groups capable of chelation), in which case removal of salts is accomplished by filtration. [0000] 4. Crystallization of Cis Prodrug Salt: [0170] Deprotection of the N6 position of the coupled phosphonic acid and chiral diol is accomplished under mild acidic conditions. The isolated coupling mixture was treated with refluxing acetic acid in ethanol to effect nitrogen deprotection. Crystallization of the resultant product using methanesulfonic acid gave rise to the cis prodrug as a mesylate salt (Formula C) with 94-98% chemical purity. The trans isomer is the major impurity and a second crystallization of the final material from an alcohol such as methanol gave greater than 96% diastereomeric purity (d.e. from 96 to 99%). [0171] The use of other acids including but not limited to such as sulfuric, nitric, hydrochloric, phosphoric, sulfonic, tartaric, citric, maleic, malic, malonic, lactic, oxalic acids and the like, may lead to better recovery and isomeric ratio of the product. The protocol as described for PMEA is also applicable to other PME or PMP derivatives. [0172] The compounds used in this invention and their preparation can be understood further by the examples which illustrate some of the processes by which these compounds are prepared. These examples should not however be construed as specifically limiting the invention and variations of the compounds, now known or later developed, are considered to fall within the scope of the present invention as hereinafter claimed. EXAMPLES Example 1 Preparation of 3-(3-chlorophenyl)-3-oxo-propanoic acid (1) [0173] The diol was prepared as described in U.S. PreGrant Published Application No. 20030225277A1. A 12 L, 3-neck round bottom flask was equipped with a mechanical stirrer and addition funnel (2 L). The flask was flushed with nitrogen and charged with diisopropylamine (636 mL) and THF (1.80 L). The stirred contents were cooled to −20° C. n-Butyllithium (1.81 L of a 2.5 M solution in hexanes) was added slowly with stirring, and the temperature was maintained between −20 and −28° C. After the addition was complete (30 min), the addition funnel was rinsed with hexanes (30 mL) and the stirred solution was then cooled to −62° C. Trimethylsilyl acetate (300 g) was added slowly with stirring, maintaining the temperature at <−60° C. After the addition was complete (about 30 min), the solution was stirred at −60° C. for 15 min. 3-Chlorobenzoyl chloride (295 mL) was added slowly with stirring, maintaining the temperature at <−60° C. After the addition was complete (about 65 min), the cooling bath was removed and the reaction solution was stirred for approximately 1.25 h, with gradual warming to 0° C. The reaction flask was cooled with an ice bath, then water (1.8 L) was added to the stirred solution. The reaction mixture was stirred for 10 min, and then diluted with t-butyl methyl ether (MTBE) (1.0 L). The lower aqueous phase was separated and transferred to a round bottom flask equipped with a mechanical stirrer. MTBE was added (1.8 L) and the stirred mixture was cooled to <10° C. in an ice bath. Concentrated HCl solution (300 mL of 12 M solution) was added and the mixture was vigorously stirred. The layers were separated and the aqueous phase was further acidified with concentrated HCl (30 mL) and extracted again with MTBE (1.0 L). The combined MTBE extracts were washed with approximately 10% NaCl solution (1 L), dried (MgSO 4 , 70 g), filtered and concentrated under reduced pressure to give 827 g of a yellow solid. The crude solid was slurried in hexanes (2.2 L) and transferred to a round bottom flask equipped with a mechanical stirrer. The mixture was stirred at <10° C. for 1 h, then filtered, washed with hexanes (4×100 mL) and dried to constant weight (−30 in. Hg, ambient temperature, 14 h). Example 2 Preparation of (S)-3-(3-Chlorophenyl)-3-hydroxypropanoic acid (2) [0174] The 3-hydroxypropanoic acid was prepared as described in U.S. PreGrant Published Application No. 20030225277A1. A 12 L, 3-neck round bottom flask was equipped with a mechanical stirrer and addition funnel (1 L). The flask was flushed with nitrogen and charged with 3-(3-chlorophenyl)-3-oxo-propanoic acid (275.5 g) 1 and dichloromethane (2.2 L). A thermocouple probe was immersed in the reaction slurry and the stirred contents were cooled to −20° C. Triethylamine (211 mL) was added over 5 min. to the stirred slurry and all solids dissolved. A dichloromethane solution of (−)-beta-chlorodiisopinocampheylborane (1.60 M, 1.04 L) was charged to the addition funnel, and then added slowly with stirring while maintaining the temperature between −20 and −25° C. After the addition was complete (approximately 35 min), the solution was warmed to ice bath temperature (2-3° C.) and stirred. After approximately 4 h of stirring an in-process NMR analysis indicated the starting material 1 was <4%. [0175] The residual starting material 1 was measured by proton NMR as follows: removing a 0.5 mL sample of the reaction mixture and quenching with water (0.5 mL) and 3 M NaOH solution (0.5 mL). The quenched mixture was stirred and the layers separated. The aqueous phase was acidified with 2 M HCl (1 mL) and extracted with ethyl acetate (1 mL). The organic phase was separated, filtered through a plug of MgSO 4 and concentrated with a stream of nitrogen. The residue was dissolved in CH 2 Cl 2 and the solvent was evaporated with a stream of nitrogen. Water (1.2 L) was added to the cloudy orange reaction mixture, followed by 3 M NaOH solution (1.44 L). The mixture was vigorously stirred for 5 min. and then transferred to a separatory funnel. The layers were separated and the basic aqueous phase was washed with ethyl acetate (1 L). The aqueous phase was acidified with concentrated HCl (300 mL) and extracted with ethyl acetate (2 times with 1.3 L each). The two acidic ethyl acetate extracts were combined, washed with approximately 10% NaCl solution (600 mL), dried with MgSO 4 (130 g), filtered and concentrated under reduced pressure to provide 328 g of a yellow oil. The oil crystallized upon standing. The resulting solid was slurried in ethyl acetate (180 mL) and transferred to a 2 L, 3-neck round bottom flask, equipped with a mechanical stirrer. The stirred ethyl acetate mixture was cooled to <10° C. (ice bath), then diluted with hexanes (800 mL). The resulting mixture was stirred at ice bath temperature for 4 h, and then filtered. The collected solid was washed with 4:1 hexanes:ethyl acetate (3×50 mL) and dried to constant weight (−30 inches of Hg, ambient temperature, 12 h). Example 3 Preparation of (S)-(−)-1-(3-chlorophenyl)-1,3-propanediol (3) [0176] The diol was prepared as described in U.S. PreGrant Published Application No. 20030225277 A1. A 12 L, 3-neck round bottom flask was equipped with a mechanical stirrer, addition funnel (2 L) and thermometer. The flask was flushed with nitrogen and charged with (S)-3-(3-chlorophenyl)-3-hydroxypropanoic acid 2 (206.7 g) and THF (850 mL), and the stirred solution was cooled to 5° C. (ice bath). A 1 M borane in THF solution (2.14 L) was charged to the addition funnel, and then added slowly with stirring maintaining the temperature at <10° C. After the addition was complete (approximately 1 h), the cooling bath was removed and the solution was stirred at ambient temperature for 1 h. The reaction solution was slowly and cautiously quenched with water (600 mL), followed by 3 M NaOH solution (850 mL). The mixture was stirred for 10 min. with an observed temperature increase to approximately 40° C., and then the mixture was transferred to a separatory funnel. The layers were separated and the aqueous phase was extracted again with ethyl acetate (600 mL). The combined organic phase was washed with approximately 10% NaCl solution (500 mL), dried (MgSO 4 , 322 g), filtered and concentrated under reduced pressure to provide 189.0 g of a pale yellow oil (101%). Example 4 Preparation 9-{2-[2,4-cis-(S)-(+)-4-(3-chlorophenyl)-2-oxo-1,3,2-dioxaphosphorinan-2-yl]methoxyethyl}adenine methanesulfonate (9) Example 4.1 Formation of Dichloridate (8) [0177] [0178] A 250 mL, 4-neck round bottom flask was equipped with a mechanical stirrer, condenser, addition funnel (25 mL) and heating mantle. The flask was flushed with nitrogen and charged with PMEA (15.05 g), dichloromethane (190 mL) and N,N-diethylformamide (6.15 g). Oxalyl chloride (15.3 mL) was charged to the addition funnel, and added slowly to the stirred reaction mixture at a rate to maintain control over gas evolution (0.5 h.). After the addition was complete (30 min.), the addition funnel was removed and the vigorously stirred mixture was heated at reflux for 4 h. Example 4.2 Coupling Reaction [0179] A 250 mL, 3-neck round bottom flask was equipped with a mechanical stirrer, a cooling bath, nitrogen inlet, thermocouple, and addition funnel (25 mL). The flask was flushed with nitrogen and charged with (S)-(−)-(3-chlorophenyl)-1,3-propanediol 3 (10.6 g) and methylene chloride (150 mL). The solution was cooled to <10° C. Titanium tetrachloride (6.2 mL) was added and a heavy precipitate formed after approximately 5 min. Triethylamine (31 mL) was added, the precipitate dissolved, and the solution turned purple. After a few additional minutes a light precipitate formed. The diol solution containing the titanium tetrachloride was added to the dichloridate solution 8 over a 90 min. period. The initial temperature was 19° C. and the final temperature was 24° C. The reaction was stirred at ambient temperature for 1 h and then quenched with methanol (90 mL). The in situ yield of the cis coupled product was 91%. The reaction mixture was washed with water (165 mL) and the layers were separated. The aqueous phase was extracted with chloroform (3×150 mL). The combined organic phases were washed with 5% sodium chloride (300 mL). The resultant brine layer contained additional product and was extracted with chloroform (6×50 mL). The combined organic phase was dried (MgSO 4 , 35 g), filtered through diatomaceous earth (Celite 521), and concentrated under reduced pressure to give an oil. The HPLC analysis samples were dissolved in methanol. [0000] HPLC Conditions: [0000] YMC-Pack R & D, R-33-5 S-5 120A, 250×4.6 mm; mobile phase: Solvent A=20 mM potassium phosphate, pH 6.2; Solvent B=acetonitrile; gradient: 10-60% B/15 min., 60-10% B/2 min., 10% B/3 min.; 1.4 mL/min.; inj. vol.=10 μL; UV detection at 270 nm. Retention times: cis 13=12.5 min., trans 14=13.0 min. [0181] The material was dissolved in ethanol (150 mL) and transferred to a 500 mL round bottom flask equipped with magnetic stirring, condenser and heating mantle. Acetic acid (16.5 mL) was added and the solution was heated at reflux for 8 h. HPLC indicated the reaction was complete. The HPLC samples were dissolved in methanol. [0000] HPLC Conditions: [0182] YMC-Pack R & D, R-33-5 S-5 120A, 250×4.6 mm; mobile phase: Solvent A=20 mM potassium phosphate, pH 6.2; Solvent B=acetonitrile; gradient: 10-60% B/15 min., 60-10% B/2 min., 10% B/3 min.; 1.4 mL/min.; inj. vol.=10 μL; UV detection at 270 nm. Retention times: cis 15=9.5 min., trans 16=9.8 min. Example 4.3 Crystallization of 9-{2-[ 2,4 -cis-(S)-(+)-4-(3-chlorophenyl)-2-oxo-1,3,2-dioxaphosphorinan-2-yl]methoxyethyl}adenine methanesulfonate (9) [0183] Methanesulfonic acid (9.03 g) was added and a precipitate formed after 15 min. The mixture was diluted with ethanol (90 mL) and heated until all solids dissolved (pot temperature=78° C.). The solution was cooled with stirring and a precipitate formed at 50° C. The resulting mixture was stirred for 4 h, with cooling to ambient temperature, then at ice bath temperature for 1 h. The mixture was filtered and the collected solid was washed with cool ethanol (2×10 mL) and dried to constant weight (−30 in. Hg, 40-50° C., overnight) to yield a pale yellow solid. Recovery=19.9 g 9 (70%). The solid cis:trans ratio was 97.8:1.7. [0184] Chiral HPLC: Pirkle covalent (S,S) Whelk-O 1 10/100krom FEC 250×4.6 mm; mobile phase=55:45, methanol: 0.1% HOAc in water; isocratic; 1.0 mL/min.; inj. Vol.=10 μL; UV detection at 260 nm; sample preparation=2.0 mg/mL in water. Retention times: cis-(R) δ=24.6 min., trans-(R) δ=27.5 min., cis-(S) 7=18.0 min. [0185] 1 H NMR (D 2 O) was used to confirm structure of components. Example 4.4 Recrystallization of 9-{2-[2,4-cis-(S)-(+)-4-(3-chlorophenyl)-2-oxo-1,3,2-dioxaphosphorinan-2-yl]methoxyethyl}adenine methanesulfonate (9) [0186] A 1 L, 3-neck round bottom flask was equipped with a mechanical stirrer, condenser, heating mantle and thermometer. The flask was charged with the crude mesylate salt 9 and ethanol (400 mL). The stirred mixture was heated at reflux (pot temperature was 78° C.) until all solids dissolved (approximately 10 min.). The stirred mixture was gradually cooled to ambient temperature over 3 h (a precipitate formed at 52° C.). The mixture was stirred at ambient temperature for an additional hour, cooled to 10° C. and stirred for another hour and then filtered. The collected solid was washed with cool ethanol (2×10 mL) and dried overnight (−30 in Hg, 45-50° C., 16 hrs.).) to yield a pale yellow solid (17.64 g, 62% overall yield). Cis:trans ratio=99.5:0.5. Color: pale yellow solid Example 5 Coupling of iodomethylphosphonic acid with (S)-(−)-1-(3-chlorophenyl)-1,3-propanediol [0187] A 500 mL 4-neck round bottom flask equipped with a heating mantle, mechanical stirring, an addition funnel, thermocouple, and a condenser with nitrogen inlet was charged with methylene chloride (80 mL), iodomethylphosphonic acid (9.88 g, 44.5 mmol), and N,N-diethylformamide (0.4 mL, 5.0 mol). The oxalyl chloride (9.0 mL, 103 mmol) was added via the addition funnel at such a rate as to maintain control over the gas evolution (0.25 h). The slurry was heated to reflux for 4 h during which time all of the solids had dissolved. The solution was cooled to room temperature. A 100 mL 3-neck round bottom flask equipped with a cooling bath, mechanical stirring, nitrogen inlet, thermocouple, and tubing adapter was charged with methylene chloride (70 mL), S(−)-1-(3-chlorophenyl)-1,3-propanediol 3 (8.85 g, 44.6 mmol). The solution was cooled to <10° C. Titanium tetrachloride (4.9 ml, 45.6 mmol) was added, and a heavy precipitate formed after approximately 5 min. Triethylamine (25 ml, 178 mmol) was added. The precipitate dissolved, and the solution turned to a purple color. After a few minutes, a light precipitate was observed forming. The diol/titanium tetrachloride solution was added to the dichloridate solution over 15 min; the initial temperature was 20° C. and the final temperature was 25° C. The reaction was stirred at ambient temperature for 1 h, and then quenched with methanol (10 mL) and water (50 mL). After separation of layers, the aqueous phase was extracted with methylene chloride (50 mL). The combined organic layers were dried over MgSO 4 , and concentrated to an oil (20 g). The ratio of major to minor isomer=3.62:1.00. by 31 P NMR (DMSO) δ=91.0 (3.62 P), 88.6 (1.00P). Example 6 Preparation of 4-{4-[2,4-cis-(S)-4-(3-chlorophenyl)-2-oxo-2λ 5 -[1,3,2]dioxaphosphinan-2-ylmethoxy]-2,6-dimethylbenzyl}-2-isopropylphenol [0188] A 500 ml 4-neck round bottom flask equipped with a heating mantle, mechanical stirring, an addition funnel, thermocouple, and a condenser with nitrogen inlet is charged with methylene chloride (190 ml), [4-(3-isopropyl-4-triisopropylsilanyloxy-benzyl)-3,5-dimethyl-phenoxymethyl]-phosphonic acid (55.1 mmol), and N,N-diethylformamide (5 mmol). Oxalyl chloride (115 mmol) is added via the addition funnel at a rate to control the gas evolution (0.5 h). The slurry is heated to reflux for 4 h. The solution is cooled to room temperature. A 250 ml 3-neck round bottom flask equipped with a cooling bath, mechanical stirring, nitrogen inlet, thermocouple, and tubing adapter is charged with methylene chloride (150 ml) and S(−)-1-(3-chlorophenyl)-1,3-propanediol (55.1 mmol). The solution is cooled to <10° C. Titanium tetrachloride (56.0 mmol) is added, and a heavy precipitate forms after approximately 5 min. Triethylamine (222 mmol) is added. The precipitate dissolves, and the solution changes to a purple color. After a few minutes, a light precipitate forms. The diol/titanium tetrachloride solution is added to the dichloridate solution over 90 min. The reaction is stirred at ambient temperature for 1 h, and then is quenched with methanol (90 ml). The cis:trans ratio is approximately 3 to 1. The solution is poured into water (165 ml). The mixture is transferred to a separatory funnel, and the layers are separated. The organic phase is washed with 5% sodium chloride solution (300 ml) and is dried over MgSO 4 . The methylene chloride is removed by vacuum distillation. THF (300 ml) and tetrethylammonium fluoride (56 mmol) is added. The solution is stirred for 1 h followed by quenching with water (50 ml). After separation of layers, the aqueous phase is extracted with ethyl acetate (50 ml). The combined organic layers are washed with brine (50 ml), dried over MgSO 4 , and are concentrated. The product, 4-{4-[2,4-cis-(S)-4-(3-chlorophenyl)-2-oxo-2λ 5 -[1,3,2]dioxaphosphinan-2-ylmethoxy]-2,6-dimethylbenzyl}-2-isopropylphenol is purified by crystallization or chromatography. Example 7 Preparation of 4-{4-[2,4-cis-(S)-4-(3,5-dichlorophenyl)-2-oxo-2λ 5 -[1,3,2]dioxaphosphinan-2-ylmethoxy]-2,6-dimethylbenzyl}-2-isopropylphenol [0189] A 500 ml 4-neck round bottom flask equipped with a heating mantle, mechanical stirring, an addition funnel, thermocouple, and a condenser with nitrogen inlet is charged with methylene chloride (190 ml), [4-(3-isopropyl-4-triisopropylsilanyloxy-benzyl)-3,5-dimethyl-phenoxymethyl]-phosphonic acid (55.1 mmol), and N,N-diethylformamide (5 mmol). Oxalyl chloride (115 mmol) is added via the addition funnel at a rate to maintain control over the gas evolution (0.5 h). The slurry is heated to reflux for 4 h. The solution is cooled to room temperature. A 250 ml 3-neck round bottom flask equipped with a cooling bath, mechanical stirring, nitrogen inlet, thermocouple, and tubing adapter is charged with methylene chloride (150 ml) and S(−)-1-(3,5-dichlorophenyl)-1,3-propanediol (55.1 mmol). The solution is cooled to <10° C. Titanium tetrachloride (56.0 mmol) is added, and a heavy precipitate forms after approximately 5 min. Triethylamine (222 mmol) is added. The precipitate dissolves, and the solution exhibits a color change to purple. After a few minutes, a light precipitate forms. The diol/titanium tetrachloride solution is added to the dichloridate solution over 90 min. The reaction is stirred at ambient temperature for 1 h, and then quenched with methanol (90 ml). The cis:trans ratio is approximately 3 to 1. The solution is poured into water (165 ml). The mixture is transferred to a separatory funnel, and the layers are separated. The organic phase is washed with 5% sodium chloride solution (300 ml) and dried over MgSO 4 . The methylene chloride is removed by vacuum distillation. THF (300 ml) and tetraethylammonium fluoride (56 mmol) is added. The solution is stirred for 1 h, and is then quenched with water (50 ml). After separation of layers, the aqueous phase is extracted with ethyl acetate (50 ml). The combined organic layers are washed with brine (50 ml), dried over MgSO 4 , and is concentrated. The product, 4-{4-[2,4-cis-(S)-4-(3,5-dichlorophenyl)-2-oxo-2λ 5 -[1,3,2]dioxaphosphinan-2-ylmethoxy]-2,6-dimethylbenzyl}-2-isopropylphenol is purified by crystallization or chromatography. Example 8 Preparation of 8-Nitro-3-[2,4-cis-4-(3-chlorophenyl)-2-oxo-1,3,2-dioxaphosphorinanyl]quinoline [0190] [0191] In a 250 mL r.b. flask, (15 mmol) of 8-nitroquinoline-3-phosphonic acid HBr salt suspended in 1,2-dichloroethane (50 mL) was combined with (37 mmol) oxalyl chloride and DMF (300 uL). The slurry was refluxed for 4 hrs then allowed to cool to rt. In a second r.b. flask, (15 mmol) of (3-chlorophenyl)-1,3-propanediol was dissolved in methylene chloride (40 mL) and cooled to −78° C. To this solution was added (15.2 mmol) of TiCl 4 . After stirring for 5 min at 0° C., (60 mmol) of triethylamine was slowly added and the resulting mixture stirred for an additional 2 min. The diol mixture was added via addition funnel to the dichloridate solution over a period of 1 hr then allowed to stir at rt overnight. The reaction mixture was quenched by adding MeOH (20 mL), stirring for 20 min then combining with 10% aqueous tartaric acid solution. After stirring for 30 more min, TMEDA (20 mL) was added (exothermic!) followed by ice water and the layers separated. The aqueous portion was extracted with methylene chloride (2×100 mL), the organics combined, dried over Na 2 SO 4 and concentrated under vacuum to afford the crude product. Flash chromatography (SiO 2 ) using DCM/MeOH (60:1 to 40:1) as the eluting gradient gave 3.3 g of product as a 25:1 cis/trans mixture. 31 P NMR (DMSO) δ=11.12 (cis), 7.19 (trans).

Methods for the synthesis of cyclic phosphonic acid diesters from 1,3-diols are described, whereby cyclic phosphonic acid diesters are produced by reacting a chiral 1,3-diol and an activated phosphonic acid in the presence of a Lewis acid.

TECHNICAL FIELD The present invention relates to intellectual property transfer and, more particularly, to transfer of intellectual property rights via a web-based infomediary. BACKGROUND Intellectual property is a highly valuable asset for many companies, particularly in technology-related industries. Intellectual property rights protect a company's investment in its products, ideas, name, and reputation, and help maintain competitive advantage. Intellectual property can be developed internally or acquired from third parties. For example, a company may secure intellectual property rights in technology developed by its employees, or obtain access to technology developed by third parties through the purchase or license of intellectual property rights. At the same, a company may seek to generate added revenue by selling or licensing its intellectual property rights to third parties. In each case, the purchaser or licensee seeks to enhance its competitive advantages, whereas the seller or licensor seeks to increase revenue. Transfer to a third party can be especially attractive when a company has not commercialized a particular technology and the applicable intellectual property rights provide little blocking protection. Finding a purchaser or licensee can be difficult, however, and often requires extensive research. Once a potential purchaser or licensee is finally identified, the process for negotiating the transfer terms can be protracted. Moreover, the time and resources necessary to both identify an opportunity and close the deal can cut into ultimate revenues. Legal services, in particular, represent a substantial cost that can substantially impact the bottom line. Also, a licensing consultant often demands a percentage of revenues in consideration of efforts in finding a purchaser or licensee. A company seeking to acquire intellectual property rights faces similar problems. The uncertain cost of transfer, in particular, may create a barrier to discussions. Often, calculation of the appropriate amount is speculative. In addition, it can be difficult to determine whether the intellectual property owner has any interest in selling its rights or granting licenses. A company also may be hesitant to approach an intellectual property owner when infringement is a concern. In particular, the company may not want to “tip off” the owner of the intellectual property rights, and thereby invite an infringement suit. Once an opportunity is identified, the company seeking rights must engage in due diligence analysis for valuation. In the end, infringement concerns, uncertainties, and expenditures of both time and resources can prevent a transfer that could be beneficial to both parties. The market for intellectual property rights also includes a small, but growing group of intellectual property investors. Intellectual property investors seek out new technologies and applicable intellectual property rights, either for product commercialization or exploitation by sale, licensing, or litigation. Intellectual property investors do not typically have infringement concerns, but are subject to some of the same problems faced by intellectual property owners and companies seeking transfer. Specifically, investors must expend substantial time and resources in the identification of opportunities. Without knowledge of an owner's posture for or against transfer, for example, the investor can pursue many leads that result in dead ends. Once the owner expresses an interest, it may be difficult to establish a market value for the intellectual property rights. Again, extensive due diligence analysis usually is necessary. With the many barriers described above, companies can easily miss opportunities to maximize revenue or enhance competitive advantage through intellectual property transfer. Intellectual property rights often are left to languish and expire while the technology goes uncommercialized. Usually, the root cause is a lack of information. SUMMARY The present invention is directed to a system and method for dissemination of intellectual property transfer information among multiple users via a global computer network such as the World Wide Web. The system and method can be used to provide network users with information to facilitate transfer of intellectual property rights by assignment or license. Also, the system and method can be configured to collect offers from parties seeking to acquire rights, or conduct a web-based auction. In this manner, the system and method provide a web-based infomediary in the sense that they facilitate person-to-person or business-to-business online exchanges that leverage the Internet to unite buyers and sellers into a single, efficient virtual marketplace that provides a concentration of pertinent information. The infomediary can be implemented via software executing on computers connected to the global computer network, and preferably takes the form of a web site on the network. In particular, multiple users may access a web site to view the intellectual property transfer information and provide interactive input using web browser applications. One or more web servers generate web pages for presentation of information requested by users, and provide input media for collection of information from users. The intellectual property rights transferred via the infomediary may include interests in patents, trademarks, copyrights, trade secrets, know-how, and mask works, including issued rights, registrations, and applications, as well as web domain names, and telephone numbers. The interests may take the form of assignments or licenses. Also, the transferred intellectual property rights may include interests in license agreements that can be assigned or sublicensed, in whole or in part, as well as options to acquire interests in rights or licenses. In particular, the rights subject to transfer may include rights to an existing or future royalty stream associated with a license agreement, or at least an option to acquire the interest in the future should the subject technology or products be commercially successful. A licensor may seek to assign a license agreement with prospective licensing revenue in exchange for discounted, present compensation. In this manner, the infomediary may facilitate a marketplace for assignment of royalty revenue. The posting of intellectual property transfer information on a network resource residing on a global computer network can provide significant value to companies or firms seeking to transfer or acquire intellectual property rights. Posting of intellectual property rights for transfer communicates the owner's willingness to dispose of the rights. The terms for transfer can be posted with a description of the intellectual property rights. The terms may include various licensing terms, and a starting offer price or minimum opening bid. Bids submitted at auction help establish a market price for the intellectual property rights. The transfer terms, including price information, can be readily accessed, eliminating much speculation and uncertainty on the part of the party seeking rights. The transfer terms can be selected by the intellectual property owner, for example, by selecting one of several form agreements provided on-line by a web site administrator. As an alternative, the intellectual property owner may upload a desired transfer agreement for posting with the information describing the intellectual property rights. Further, the system and method may permit the owner to select a number of different terms, for example, using a check-box, pull-down menu, or radio button format presented on a web page generated by the web server. In this manner, the user can produce a customized set of terms, or at least modify terms set forth in the form agreements In any event, the potential purchasers or bidders are able to view the terms prior to submitting a bid, and thereby assess the value of the proposed transfer relative to cost. The terms may efficiently set all of the substantive provisions of the transfer, such as scope, consideration, duration, indemnification, continuing prosecution, and warranties, leaving no opportunity for negotiation. Alternatively, the terms may address only key issues and contemplate further negotiation once the parties agree on price and scope. For efficiency, it may be desirable that the terms be comprehensive, and that further negotiation be conducted only in rare cases. In an auction format, in particular, bids are submitted in contemplation of a fixed set of terms. Accordingly, negotiation may be less prevalent in when rights are auctioned. If negotiation is necessary, the parties may communicate via the web site or using more conventional modes such as email, facsimile, telephone, and personal communications. The terms of the transfer will ordinarily specify an up-front cash payment, royalties, or a combination of both. In some cases, however, the owner may entertain offers for cross-license of third party rights. In exchange for a license under rights owned by one party, for example, another party may offer a license under rights that it owns. Cross-licensing is prevalent in many industries, of course, as a means to avoid potential blocking situations, settle litigation, or open new opportunities. The infomediary can provide an efficient and mechanism for identifying cross-licensing opportunities. To facilitate evaluation and due diligence, the information posted for a proposed transfer can be quite extensive. For a patent, for example, the information may include electronic copies of the pertinent patent, prosecution history, litigation history, and family history, as well as pertinent prior art references and web sites associated with the patent assignee, and links to related patents, e.g., sharing common filing date priority. Advantageously, in many cases, this information can be gathered from public domain databases distributed across the global computer network. Copies of patents, for example, can be gathered from public domain resources associated with patent offices around the world. The U.S. Patent and Trademark Office web site (www.uspto.gov), for example, provides both text and images of issued U.S. patents. The information posted by the web server may incorporate such text and imagery or, more preferably, provide hypertext links to them. Also, the information may include links to documents, such as uploaded agreements, that are stored on a file server accessed by the web server. Intellectual property owners can submit particular rights as items for sale, exchange or auction via a web browser interface. In particular, when the user selects a hypertext link for submission of a transfer item, the web server may kick off one or more web pages that prompt the user for appropriate information, including the identity of the owner and the intellectual property right, and links to other supplemental information. The web pages also may direct the owner through a process for selection of terms. Alternatively, the owner may be equipped with a local asset control center that tracks and maintains intellectual property assets. The asset control center can be configured to upload a group of items on an automated basis upon selection by a user. In either case, the web server interacts with a database server and file server to create database records and archive files relating to each item. When a potential purchaser requests access to an item for evaluation, the web server retrieves the appropriate information and presents it in HTML format. It may be desirable, for example, to “package” or “pool” separate intellectual property rights for transfer. In this manner, a number of related intellectual property rights, perhaps representing a particular technology portfolio, can be combined for placement with a single entity. Packaging may add scope or term to the item being offered, or offer synergies between the rights, increasing the value of the transfer item and the size of offers or bids. The matters could be combined, on the basis of similarity of technology or product line. Also, a company could package all of the intellectual property rights for a particular business, or package a number or related license agreements to increase overall package value based on cumulative royalty streams. Alternatively, a number of generally unrelated rights can be packaged simply on the basis of convenience. Indeed, if negotiation of terms is necessary, dealing with a single entity, instead of several, can provide the owner with administrative advantages whether subject matter is similar or not. Packaging also can simplify the offer or bidding process, reducing the number of different matters up for bid. Further, packaging can promote the participation of larger companies. Instead of making offers or bidding on several individual matters, a company may see more value in a portfolio of intellectual property rights or agreements. In addition to packaging its own intellectual property rights, an owner may seek out other owners and attempt to pool its rights with those of one or more additional owners. In other words, two or more owners may choose to pool their intellectual property rights for the offer or bidding process, again increasing the volume of technology. Ordinarily, pooling by different parties will involve related intellectual property rights, e.g., patent rights for related technology, that provide synergy or greater scope of coverage. Two different universities, for example, may decide to pool intellectual property rights with respect to similar technologies and increase the value of the overall transfer item. Often, with intellectual property, the whole can be much greater than the sum of the parts, particularly where blocking rights are implicated. The offer or bidding process also may have a collective aspect in terms of the parties seeking to acquired rights. In particular, parties seeking transfer of intellectual property rights may have the capability to pool their offers or bids. When a larger or higher value package of intellectual property rights is posted for bidding, smaller companies may have insufficient resources to purchase or license them. To promote access to larger or more costly portfolios, smaller companies may pool their bids and then divide the resulting rights among themselves. Of course, the companies will be cognizant of the resulting reduction in individual value when the rights are divided. When the companies desire to manufacture different components of an overall product, however, access to applicable intellectual property rights can be mutually beneficial. In this manner, smaller or more narrowly focused companies can compete with larger, more diversified companies without compromising their growth plans or stretching themselves too far. The firms that pool their offers or bids may have preexisting relationships, and may identify themselves as a bidding collective for purposes of the offer or bidding process. Alternatively, pooling may take place on an ad-hoc basis, and be facilitated by communication between the companies. If the firms are registered as a bidding collective, one of the firms may be designated to enter bids for the entire collective. Alternatively, firms may submit individual bids that are then summed to produce a total bid on behalf of the collective. For example, two firms may enter and increase bids individually during the course of an auction, but request that they be combined upon receipt. The total bid is compared to bids submitted by other collectives or individuals. In any bid or offer pooling arrangement, an agreement concerning division of the transferred subject matter ordinarily will be necessary. In the case of pooling owners, an agreement apportioning proceeds will be desirable. Similarly, for pooling purchasers or bidders, division of the transferred rights will be desirable. For this reason, the web site may provide a group of form agreements that govern the rights of pooling parties relative to one another. Alternatively, the parties may formulate their own agreement, which can be executed in advance of the offer or bidding process or following transfer. Transfer terms may specify an offer and acceptance process whereby the owner entertains individual offers and accepts the most attractive one. The owner preferably sets an initial offer price. As an alternative, transfer terms may call for an auction process, and set a minimum opening bid. In each case, for efficiency, the offer or bid will conform to the terms set forth by the owner. If the owner specifies an up-front payment and running royalties, for example, offers or bids should be made in that form and take into account the particular royalty base set by the owner. As an illustration, bidders may submit bids that offer a specified amount for the up-front payment and a percentage royalty rate applicable to the specified royalty base. Thus, the bidders could vary either of the terms, i.e., up-front or royalty rate, in submitting bids. Some agreements may be considerably more complex, specifying up-front payments, quarterly minimums, multiple royalty rates applicable to different products, volume discounts, paid up license amounts, and the like. The terms of transfer can range from the mundane to the exotic. In one case, an owner may simply offer assignment of an intellectual property right for a lump sum. In another case, the owner may offer a partial interest ranging, for example, between a nonexclusive license, an exclusive license, a field of use license, and a license for particular products or geographic areas. Specification of the above terms can be facilitated by check-boxes or other input media presented to the owner in the form of web pages generated by the web server. Still other features can add significant value to the process. In the event a particular transfer item does not entertain sufficient offers or bids during an initial offer or auction period, the web site may provide a mechanism that automatically reduces the opening offer price or minimum bid price of the transfer item. The owner may be contacted in advance of the decrease, or simply permit the reduction to proceed automatically. In some cases, the owner may specify a series of reductions in advance, and also select periods of time between reductions. A transfer item may remain at a particular value for a period of five days, for example, before reduction to the next level. In this manner, the transfer item effectively reduces itself until it reaches a level at which bids or offers are attracted. As another feature, an automated mechanism may provide for disposal of intellectual property rights short of transfer to a purchaser. Specifically, in the event no offers or bids are collected within a period of time, which may include multiple reductions in price, the web site may automatically record a donation of the rights to a charitable organization. The web server may generate appropriate paperwork for the owner and charitable organization for signature, either manual or electronic. The web server subsequently issues a receipt for the donation indicating the market value of the rights donated. Consequently, the owner of the rights is given a convenient and automated mechanism for deriving value for intellectual property assets. Indeed, some owners may elect to bypass an offer or auction process, and simply donate the assets electronically. The fair market value of the donated rights can be determined by staff associated with the web site administrator or agreed upon by the owner and the charitable organization. It is important to note that the donation mechanism, like many other features of the present invention, is not necessarily limited to transfer of intellectual property assets. Rather, the donation mechanism conceivably can be applied to a variety of different assets including both real and personal property, financial instruments, agreements, and other items. To increase the number of available transfer items, the web site can be integrated with an automated search mechanism that actively seeks intellectual property rights that may be ripe for transfer. The search mechanism may constitute a web crawler that monitors publicly accessible resources on the network that are likely to yield information concerning distressed assets. For example, the search mechanism may monitor resources that report bankruptcy-related information or financial information for companies. In this manner, the search mechanism may identify parties more likely to be interested in disposing of assets in exchange for monetary consideration. The crawler can be equipped with necessary intelligence to determine whether the parties are likely to possess substantial intellectual property assets. Upon identification of a company that has entered bankruptcy or is experiencing financial difficulties, the web server can be configured to transmit a message advising the party of the availability of transfer services and inviting the party to submit information concerning its intellectual property rights for transfer. The message can be transmitted, for example, via email, facsimile, or other modes, to actively solicit the addition of items for transfer. Another feature that can be incorporated in the transfer web site is a transactional “blind” mechanism. For parties seeking rights, this feature serves in avoiding tipping off an intellectual property owner as to a potential infringement. The party seeking a license or other interest simply identifies the rights in which it is interested, and transmits this information to the web server. The web server, in turn, sends a message advising the intellectual property owner of that party's interest in obtaining rights. The identity of the party is maintained in confidence, providing anonymity. The message can simply invite the owner to specify whether it is interested in a potential transfer and, if so, a set of terms including an opening offer price. Alternatively, the party seeking rights may specify an opening offer that is communicated to the owner with the message. If the owner expresses an interest, the web server generates a series of web pages that prompt the owner for entry of background information. Ultimately, the identity of the party seeking rights must be disclosed. Preliminary investigation on an anonymous basis, however, can permit a party to determine whether the owner has any interest in discussing a transfer. The infomediary plays the role of a “blind” for purposes of investigating a potential transfer, and conceals the identity of the party seeking transfer to avoid tipping off the intellectual property owner. Other advantages, features, and embodiments of the present invention will become apparent from the following detailed description and claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a system for facilitating transfer of intellectual property via a global computing network; FIG. 2 is a block diagram illustrating the management and generation of intellectual property transfer item information in the system of FIG. 1 ; FIG. 3 is a diagram of a web page illustrating a categorization of intellectual property assets into different intellectual property rights; FIG. 4 is a diagram of a web page illustrating categorization of an intellectual property category into different technology or industry sub-categories; FIG. 5 is a diagram of a web page illustrating intellectual property assets listed as items for proposed transfer; FIG. 6 is a diagram of a web page containing descriptive information for a particular transfer item; FIG. 7 is a diagram of a web page containing active bidding information; FIG. 8 is a diagram of a web page containing bid history information; FIG. 9 is a diagram of a web page communicating a bid in the form of a cross-licensing offer; FIG. 10 is a diagram of a web page illustrating a list of transfer terms for an intellectual property asset; FIG. 11 is a diagram of a web page illustrating a dialog for selecting transfer terms; FIG. 12 is a diagram of a web page containing a dialog for packaging of intellectual property assets owned by an individual; FIG. 13 is a diagram of a web page containing a dialog for pooling of intellectual property assets owned by two or more parties; FIG. 14 is a diagram of a web page containing a dialog for interaction with a licensing blind process; FIG. 15 is a flow diagram illustrating submission of an intellectual property asset for transfer; FIG. 16 is a flow diagram illustrating the execution of a bid process for transfer of an intellectual property asset; FIG. 17 is a flow diagram illustrating packaging of transfer items by an individual; FIG. 18 is a flow diagram illustrating pooling of transfer items by two or more individuals; FIG. 19 is a flow diagram illustrating pooling of offers or bids by two or more individuals; FIG. 20 is a flow diagram illustrating a process for a modification of terms or donation of a transfer item; FIG. 21 is a flow diagram illustrating operation of a transactional blind process; FIG. 22 is a block diagram illustrating a system for uploading of information 5 pertinent to an intellectual property asset from a client to an infomediary; FIG. 23 is a block diagram illustrating a system for identifying parties in possession of potential transfer items; FIG. 24 is a flowchart of a method for facilitating transfer of an interest in at least one an intellectual property asset, in accordance with an embodiment, FIG. 25 is a flowchart of a method for facilitating transfer of an interest in at least one an intellectual property asset, in accordance with another embodiment; and FIG. 26 is a flowchart of a method for auctioning an interest in at least one intellectual property asset, in accordance with an embodiment. Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION FIG. 1 is a block diagram illustrating a system 10 for facilitating transfer of intellectual property via a global computer network, such as the world wide web 12 . System 10 can be used to practice methods for facilitating transfer of intellectual property via a global computer network. As shown in FIG. 1 , system 10 may include a number of user computers 14 , 16 , 18 , 20 , a web server 22 , a database server 24 , a transfer item database 26 , and an access profile database 28 . Web server 22 , database server 24 , transfer item database 26 , and access profile database 28 together form ip transfer infomediary 27 . User computers 14 , 16 , 18 , 20 and server 22 are connected via world wide web 12 . Web server 22 administers an auction or offer-acceptance process for transfer of intellectual property, acting as an infomediary between parties seeking to transfer intellectual property assets. For purpose of illustration, the following description places some emphasis on the administration of an auction process. It should be recognized, however, that the web-based infomediary provided by system 10 may be extremely useful in administering an offer-acceptance process in which the ip seller posts an item for transfer at a given offer price, and simply sells to the first ip buyer willing to pay the specified price. In this manner, transfer items may be posted for sale, license, or other transfer without the administration of an auction process with multiple bids. Web server 22 may take the form of a single web server or multiple web servers, and may execute server page scripts. The scripts can be written as Active Server Pages (ASP) or in other server based scripting languages such as CGI. ASP is bundled with the Microsoft Internet Information Server. ASP code is mixed within HTML in a web page and does not need to be compiled separately. Accordingly, ASP commands can be simply added to pages executed by web server 22 to modify its operation. ASP is especially useful in building database driven websites. In particular, ASP can allow browser users to manipulate databases, e.g., view, edit, and manage, from any browser using HTML and active data objects, and allow HTML web pages to generate database updates. In operation, web server 22 interacts with database server 24 to provide network users with access to intellectual property information contained in a relational database 26 . Web server 22 assembles the necessary content for web pages requested by users, and accepts information from users for addition to database 26 . Database server 24 may be any type of server, and simply requires an OLEDB or ODBC driver for interaction with web server 22 . In response to queries from web server 22 , database server 24 locates appropriate records within database 26 . An access profile database 28 defines access profiles that limit the scope of information available to particular network users. Computers 14 , 16 , 18 , 20 may take the form of personal computers, Macintosh computers, workstations, handheld computing devices, or the like, equipped with telecommunications services for access to network 12 . Computers 14 , 16 , 18 , 20 can be connected to network 12 directly or via an interne service provider, and communicate using a network protocol such as TCP/IP. Each computer 14 , 16 , 18 , 20 executes a viewing application such as a web browser 30 to access resources residing on other computers attached to network 12 . In particular, web browser 30 permits a network user to view html web pages generated by web server 22 . In system 10 , network users include parties who own intellectual property assets such as patents, trademarks, copyrights, trade secrets, mask work rights, domain names, or telephone numbers, or having the right to assign or sublicense agreements with respect to any of such rights. Such parties will be generally referred to herein as ip sellers. Network users also include parties seeking to acquire any of the intellectual property assets described above. Such parties will be generally referred to herein as ip buyers. The ip buyers and sellers connected to system 10 desire to participate in an active auction of offer/acceptance process for the transfer of intellectual property assets. The number of network users in system 10 can be virtually unlimited, although system operation may be subject to bandwidth limitations of server 22 and network 12 . IP sellers situated at computers 14 , 16 , 18 , 20 submit information to web server 22 via network 12 , and view information pertaining to auction bid status. IP buyers view intellectual property asset information provided by web server 22 and submit bids for purchase or license of intellectual property assets, or assignment of intellectual property agreements. Each transfer item record in database 26 includes information describing a particular intellectual property asset for which bids will be accepted. The information may include the identity of the ip seller, a detailed description of the asset, hypertext links to other network resources providing additional documentation, projected dates for evaluation and active auction periods, and a minimum opening bid. The level of specificity and volume of information will vary according to the type of asset, but should assist potential bidders in assessing the value of the proposed transfer. If a particular transfer item involves a patent, for example, the information may include hypertext links to electronic copies of the patent, the patent prosecution history, pertinent prior art, pertinent court documents in the event the patent has been subject to legal action, assignment recordation data to reflect a chain of title, any agreements affecting the scope and value of the asset, pertinent products and competitors, and a variety of additional information useful in valuation and due diligence. The information can be presented in a text or graphic format and, as mentioned above, may include hypertext links to each informational item. Also, the information may include downloadable files, e.g., in PDF format, that convey additional information. Examples of documents that can be conveyed to network users as downloadable files are background items such as invention disclosures, drawings, briefs, opinions, and the like. Notably, the ip seller may also rely on uploaded documents to convey the terms of the transfer, for example, by uploading entire license agreements for review by prospective ip buyers. Again, publicly available information can be obtained by simply linking to a publicly accessible web site. In the case of U.S. prior art patents, for example, the web page may include a link to the United States Patent and Trademark Office web page at www.uspto.gov. Additional prior art can be obtained by linking to web sites associated with other national patent offices. For submission of an intellectual property asset as a transfer item, an ip buyer accesses web server 22 and selects an appropriate web page. Web server 22 then kicks off a series of interactive web pages requesting user input. A first web page, for example, may request the entry of the ip buyer name, a title for the transfer item, and perhaps a brief description or categorization of the ip asset, e.g., electrical patent or trademark for the beverage industry. Subsequent web pages may request entry of a minimum bid price, a auction date, and adverse parties for whom access to the information should be prohibited. An ip buyer may wish to exclude competitors from bidding, for example, and in many cases prevent the competitors from learning that certain assets are being posted for auction. Other web pages may provide a dialog that prompts the user to define an access profile for the transfer item, as will be described. Further, another web page may prompt the user for any unloadable files that describe the transfer item or transfer terms in greater detail. Background information also can be provided in the form of hypertext links to other web pages. The files are uploaded to the web server or, alternatively, could be uploaded to an ftp server. The dialog driven by the web pages can be aided by conventional input media such as check boxes, radio buttons, pull-down menus, text entry boxes and the like. FIG. 2 is a block diagram illustrating management and generation of transfer item information in system 10 . Upon receipt of transfer item information from an ip seller, web server 22 interacts with database server 24 to create a record for incorporation in transfer item 26 . Web server 22 provides the information to file server 29 , which then stores the information in an archive 31 for later retrieval. File server 29 may store several different files for a single transfer item record, particularly when additional files such as agreements or background documentation are uploaded to web server 22 by the ip seller. When a user requests access to the information, web server 22 interacts with database server 24 to retrieve the pertinent transfer item record from database 26 and obtain the addresses of pertinent files stored by file server 29 . Web server 22 then retrieves the files and formulates the content of the web page for viewing by the network user. A firewall preferably is provided as a security measure. The firewall separates database server 24 and file server 29 from web server 22 to avoid unauthorized intrusions into the ip seller. Due to its nature as a repository of information concerning intellectual property assets and transfer terms, the security and confidentiality of database 24 and file server 29 is a serious concern. To promote increased security and confidentiality of transfer item information, web pages generated by web server 22 can be communicated to network users using public key encryption mechanisms such as SSL. Other security measures, such as the use of login accounts for network users, can provide added benefits. In preferred embodiments, however, the information provided by system 10 is accessible without extensive login procedures in order to maintain the level of convenience for which web browsers are known. Access profile database 28 defines access profiles for transfer items and network users. An access profile for a transfer item is defined by the pertinent ip seller. An access profile for a network user is generally defined by that network user. An access profile serves to limit access to particular information by particular network users. Database server 24 consults access profile database 28 when information is requested by a particular user. At the request of an ip seller, for example, an access profile for a transfer item may exclude certain ip buyers from access to transfer items submitted by the ip seller. Alternatively, at the request of an ip buyer, an access profile may limit the scope of information viewed by the ip buyer to a desired area. For purposes of illustration, FIGS. 1 and 2 show a discrete access profile database 28 . In practice, however, a separate access profile database 28 may be unnecessary. Rather, an integrated database schema that takes into account the access profiles of particular transfer items and network users may be sufficient. An ip seller can specify an access profile for a transfer item to exclude particular network users from access to its transfer item records and participation in the auction process. The access profile for a transfer item serves the basic purposes of limiting access to confidential or sensitive information to authorized ip buyers, or excluding particular ip buyers such as competitors from access. In other words, the access profile may include an inclusive list of ip buyers who are authorized to bid on the transfer item, or an exclusive list of ip buyers who or not. Generation of the access profile may take place as part of the process for submission of the transfer item. In this case, web server 22 may present one or more web pages that request profile information or give the user an opportunity to select a default profile that is either general to all users or formulated for the particular user based on past submissions. An ip buyer also can define an access profile to limit the scope of information presented, e.g., as part of initial user registration. The access profile can be applied to the individual ip buyers on a global basis, or divided into several sub-profiles that span different technology areas or ip categories. An ip buyer may have one sub-profile that defines access for transfer items in the semiconductor fabrication area, for example, and another sub-profile that defines access for transfer items in the electronic components area, e.g., to exclude access to transfer items from known competitors, which may differ from area to area. In this manner, the access provided to different ip buyers can be highly customized, and adjusted according to individual needs. The access profile for an ip buyer serves various objectives. In particular, the ip buyer can use the access profile to limit exposure to trade secrets or other confidential information of competitors. To minimize exposure, the ip buyer may request that it not be exposed to transfer items concerning a particular company. Also, the ip buyer may define the access profile to exclude particular technology or business areas in which the ip buyer is not interested. Specific transfer items then can be identified for exclusion based on ip seller name, business area, or technology area, as obtained from fields in the transfer item records stored in database 26 . Moreover, a system administrator may formulate a set of system-wide default profiles that specify particular ip buyers for access to particular transfer items. The system administrator may designate a finite set of ip buyers to access all transfer items in a particular technical area. The default profiles set by the system administrator can make the presentation of information to ip buyers more efficient by limiting the bidding group to parties that are more likely to be interested. At the same time, the system administrator may select ip buyers on the basis of business, technology, and even financial strength, to improve the quality of the bidding group to the benefit of the ip seller. For purposes of illustration, FIGS. 3-14 show a hierarchy of web pages viewed by a network user in an exemplary embodiment of system 10 . FIG. 3 is a diagram of a web page illustrating a categorization of intellectual property assets into different intellectual property rights. In the example of FIG. 3 , the web page is entitled “IP EXCHANGE.” Upon access to web server 22 , the network user may be presented with links to a web page for submission of a transfer item by an ip seller, or for access to pending transfer items, i.e., patents, trademarks, trade secrets, copyrights, mask work rights, web domain names, telephone numbers, or agreements that have been posted for evaluation prior to bidding or are engaged in active bidding. As shown in FIG. 3 , when a user desires access to pending transfer items, web server 22 generates a web page that offers the user a choice of different categories of intellectual property. Agreement categories may be subsumed within the particular intellectual property categories to which they pertain. For example, a patent license agreement may be provided in the patent category. Alternatively, agreements may be designated as an individual category. The listing will vary according to the user's access profile, which may exclude certain categories. Some ip buyers may have no interest in mask work rights, for example, while others may have no desire to review trademark-related transfer items. The category titles are represented as hypertext links to other web pages. Upon selection of one of the hypertext links, the user is presented with another web page devoted to the pertinent category. In the example of FIG. 3 , the arrow designates user selection of the patent category. FIG. 4 is a diagram of a web page illustrating categorization of the patent area into either technology areas, e.g., electrical and computer, chemical, biotech, or mechanical, or industries, e.g., interne, software, data storage, semiconductor, imaging, medical devices, bio-pharmaceutical. Other technology or industry areas will be susceptible to similar sub-categorization. The arrow in FIG. 4 designates user selection of the data storage category. FIG. 5 is a diagram of a web page illustrating patent rights proposed for transfer in the data storage technology area. In the example of FIG. 5 , the data storage technology area of the patent category yields a number of different patents listed by patent owner and patent title. Other information can be provided on the initial web page illustrated by FIG. 5 . Such information may be provided, however, via hypertext links to other web pages. To obtain further information concerning item 1, for example, the network user may click on the title of the invention “Magneto-Optic Recording Medium.” Subsequent linked web pages may yield a variety of information such as electronic copies or links to the patent, prosecution history, pertinent prior art, and other background documentation helpful in assessing the scope, validity, and resultant value of the patent. To learn more about the patent owner, the network user may click on the name of the patent owner. Subsequent linked web pages may yield a variety of information such as web pages associated with the patent owner, competitors, products, or industries. FIG. 6 is a diagram of a web page containing descriptive information for a particular transfer item. Upon selection of a particular transfer item, as indicated by the arrow in FIG. 5 , the user views a web page that provides additional information as well as a number of links to further information. As shown in FIG. 6 , information for the patent entitled “Magnetic Tape Cartridge” may include the pertinent patent number and a brief description of the proposed transfer, e.g., assignment of the patent, assignment of a patent license agreement, grant of an exclusive license, or grant of a nonexclusive license. Further, as shown in FIG. 6 , the information may include the names of the inventors, the dates of the active bid period, a minimum bid, and links to a number of items including transfer terms, which may take the form of one of several form agreements provided by the system administrator, a customized agreement formulated on-line by the ip seller, or a customized agreement that is uploaded to web server 22 by the ip seller. Also, the information may include hypertext links to other network resources providing information such as pertinent prior art, related patents, the patent prosecution history, and the home web page for the ip seller. In the example of FIG. 6 , the proposed transfer involves assignment of an existing patent license agreement between XYZ Corp and ABC Corp. For example, XYZ may be the licensor, and may desire to assign the agreement along with an associated prospective royalty stream in consideration of a sum calculated by discounting the estimated net present value of the royalty stream. Accordingly, the information also may include links to an electronic copy of the pertinent license agreement, past royalty reports, and a link to the ABC home web page. Links also can be provided to allow the ip buyer to request more information or enter the bidding process in the event it is already underway. Following selection of the “Enter Bidding” link, the user views a web page such as that shown in FIG. 7 . In particular, FIG. 7 is a diagram of a web page containing active bidding information. In addition to background information provided as shown in FIG. 6 , the web page of FIG. 7 includes a dialog box that displays the current high bid, and provides a text entry box for entry of a bid by the present ip buyer and a button for submission of the bid. As will be explained, system 10 may provide the capability to perform a cross-licensing transaction, in which case the ip buyer may offer a cross-license to certain ip assets in lieu of the transfer terms proposed by the ip seller. For this reason, the dialog box also may include a “X-License” button to initiate entry of the cross-license terms by the ip buyer. FIG. 8 is a diagram of a web page containing bid history information for review by the ip seller. Disclosure of bids among ip buyers may or may not be desirable, and will be a matter of design for the system administrator, or perhaps a matter of choice for the ip seller. In any event, the ip seller can access a web page as shown in FIG. 8 to review the bids submitted by ip buyers. In most embodiments, the ip seller will be required to accept the high bid. In some embodiments, however, the ip seller may reserve the right to select a lower bid. The ip seller may want to accept a lower bid, for example, based on considerations of the competitive posture of the ip buyer relative to the ip seller or the perceived financial strength of the ip buyer. In this manner, the ip seller can exercise discretion before transferring its intellectual property rights to an undesirable bidder such as a direct competitor. Of course, in some embodiments, the use of access profiles may serve to exclude direct competitors from the bidding process altogether. FIG. 9 is a diagram of a web page communicating a bid from an ip buyer in the form of a cross-licensing offer. As shown in FIG. 9 , the proposed cross-licensing offer information detailed on the web page may specify another intellectual asset, such as a patent, and provide much of the same information as provided for any transfer item. For example, the cross-licensing offer may specify the name of the bidder, the pertinent patent number or numbers, and provide links to electronic copies of the patents, prior art, prosecution histories, and license agreements. Negotiation of the cross-license terms ordinarily will require added dialog between the ip buyer and seller, which can be facilitated by email or a chat mechanism, or take place over the phone. Concentration of the necessary cross-licensing information in a single web page or collection of web pages, however, will serve to initiate the process and allow the ip buyer to determine whether further discussions are warranted, or whether the cross-licensing offer should be dismissed out of hand. FIG. 10 is a diagram of a web page illustrating a list of transfer terms for an intellectual property asset. As an alternative or in addition to a fully-developed transfer agreement, the ip seller may post a set of transfer terms that outline the proposed transfer. By clicking on the transfer terms link, the ip buyer can obtain ready access to this condensed version of the deal. As illustrated in FIG. 10 , the transfer terms may specify the scope of the license in terms of nonexclusive or exclusive, any fields to which the assignment or grant will be limited or excluded from, applicable royalty rates and bases, the duration (term) of the agreement, any up-front payments, any support or technology transfer obligations, and any other terms that the ip seller may wish to communicate to bidders. The “other” terms may conform, for example, to a default list of terms specified for each type of transaction and set by the system administrator for selection by ip sellers. FIG. 11 is a diagram of a web page illustrating a dialog for selecting transfer terms. Upon access to web server 22 , the ip seller selects a link for submission of a transfer item. Following submission of background information, the ip seller may set the terms of transfer by uploading a custom agreement, selecting one of several form agreements provided by the system administrator, or initiating a dialog as shown in FIG. 11 for selection of individual terms. The dialog takes the form of a menu that can be equipped with conventional input media such as radio buttons, check boxes, sliders, pull-down menus, text entry boxes, and the like. In this manner, the ip seller can enter transfer terms by checking boxes and selecting from a variety of stock terms provided on the menu. Accordingly, the selection of transfer terms can be made extremely convenient for the ip seller. This web page ordinarily will include a link that permits incorporation of custom terms in addition to the stock items. FIG. 12 is a diagram of a web page containing a dialog for packaging of intellectual property assets owned by an individual. An ip seller may wish to “package” separate intellectual property rights for transfer. In this manner, a number of related intellectual property rights, perhaps representing a particular technology portfolio, can be combined for placement with a single entity. The matters could be combined, for example, on the basis of similarity of technology or product line. Also, a company could package all of the intellectual property rights for a particular business, or package a number of related license agreements to increase overall package value based on cumulative royalty streams. Alternatively, a number of generally unrelated rights can be packaged simply on the basis of convenience. As shown in FIG. 12 , packaging can be facilitated by a web page that displays all of the transfer items pending for a particular ip seller. In the example of FIG. 12 , ABC Corp. has a number of different intellectual property assets posted for transfer and ranging from patents to copyright to agreements. Each transfer item may be associated with a check box that, in contrast to a radio button, permits selection of multiple transfer items for packaging. The ip seller simply clicks on the group of transfer items to be packaged, and clicks on a submit button. In response, web server 22 associates the transfer items and generates a web page for formulation of transfer terms with respect to the package. The transfer items thereafter are presented as a package, and enter the auction phase as a package for evaluation by ip buyers. FIG. 13 is a diagram of a web page containing a dialog for pooling of intellectual property assets owned by two or more parties. In the example of FIG. 13 , an ip seller can enter a pooling dialog in which a party or parties with whom the seller wishes to pool assets is selected. Following this selection, the web page displays the transfer items for the initial ip seller and the party with whom pooling is desired. Using check boxes, for example, the ip seller selects a group of transfer items from each party for pooling. Following submission of the proposed pool, the other party is notified, facilitating discussion between the parties for acceptance, rejection, or further negotiation of the terms of the pool. The transfer items are posted together as a pool in the event the parties come to agreement. FIG. 14 is a diagram of a web page containing a dialog for interaction with a licensing blind process. In this case, infomediary 27 facilitates anonymous or semi-anonymous dialog between prospective ip sellers and buyers, particularly when infringement claims are a concern. For parties seeking rights, for example, this feature serves in avoiding tipping off an intellectual property owner as to a potential infringement. The party seeking a license or other interest simply identifies the rights in which it is interested, and transmits this information to web server 22 . Web server 22 , in turn, sends a message advising the intellectual property owner of that party's interest in obtaining rights. The identity of the party is maintained in confidence, providing anonymity. This process can be facilitated by a simple web page, as shown in FIG. 14 , by which the prospective ip buyer describes a target asset by entering pertinent patent numbers, countries in which the patents are in force or which are of interest, assignees if known, and initial terms or other parameters if desired. Also, the ip buyer may have the option of disclosing its identity immediately, or reserving its identity until it becomes apparent that the ip seller's terms are likely to be within a comfortable margin of the ip buyer's terms. Following submission of the blind information, web server 22 initiates contact with the ip owner and invites that entity to enter into initial discussions. In the event the ip buyer provides a set of initial terms, and such terms are wholly unacceptable, the ip owner may simply decline further discussions. FIG. 15 is a flow diagram illustrating submission of a transfer item by a client for the bidding process. The order of events illustrated in FIG. 15 is purely exemplary. Submission preferably is guided by a series of web pages generated by web server 22 that query the client for appropriate information. In another embodiment, the client may submit one or more transfer items using an ftp session initiated by the client with an ftp server residing in system 10 . Submission of transfer items to web server 22 will be described with respect to FIG. 15 . As indicated by block 32 , the client first selects an asset type, which may involve navigation through a hierarchy of ip categories, technology areas, industry areas, and so forth. Following selection of the asset type, the user may enter a reference number for the asset, as indicated by block 34 , such as a patent number, registration number, or a simple ad hoc reference number created by the ip seller. Next, as indicated by block 36 , the ip seller may enter a brief abstract of the transfer item. The abstract can be entered manually or uploaded to web server 22 . As indicated by block 38 , the ip seller may submit a number of background documents that describe the transfer item in greater detail. For example, the user may be prompted to upload documents such as agreements, royalty reports, briefs, legal memoranda, invention disclosures, and the like. As indicated by block 40 , the user also may provide links to other network resources that contain information such as patents, prosecution histories, and prior art, in the case of a patent-related transfer item. As further shown in FIG. 15 , the ip seller then may set the access profile for the particular transfer item, for example, by entering a list of excluded parties, as indicated by block 42 . In particular, the ip seller may specify a number of competitors or other undesirable bidders who are to be excluded from access to information concerning the transfer item. Also, in some embodiments, the ip seller may submit an inclusive list of ip buyers who are desired bidders, and who are to be notified of the posting of the transfer item for auction. Finally, as indicated by block 44 , the ip seller may enter the terms of the transfer, e.g., using a web page dialog as described with reference to FIG. 11 , selecting form agreements, or uploading custom agreements. In addition to the items described with reference to FIG. 15 , the ip seller may enter additional information such as desired auction dates, packaging instructions, and reduction dates for reduction of the minimum bid. FIG. 16 is a flow diagram illustrating the execution of a bid process for transfer of an intellectual property asset. Upon receipt of a request to view transfer items for bid, as indicated by block 46 , web server 22 interacts with database server 24 to identify the particular bidder and retrieve the pertinent access profile, as indicated by block 48 . The bidder can be identified, for example, by a cookie or other device passed to computer 14 , 16 , 18 , 20 used previously by the bidder to access web server 22 , or by a log-in process. Based on the access profile, web server 22 retrieves a number of authorized transfer items for bid (block 50 ), i.e., transfer items consistent with the access profile, defined by transfer item records residing on database 26 . The transfer items may be further limited by the ip buyer's selection of particular categories and sub-categories of transfer items during navigation of the web pages generated by web server 22 . The number of options listed on each web page may be limited, however, by the access profile. As indicated by block 52 , web server generates a web page that displays the pending transfer items for evaluation by the ip buyer. The ip buyer may view the information associated with each of the transfer items by hypertext navigation. Also, for each transfer item, the ip buyer may enter a request for further information that is processed by web server 22 , as indicated by block 54 . Upon notification of the client and receipt of the requested information, web server 22 updates the information and makes it available to the ip buyer, as indicated by block 56 . The ip buyers may periodically visit and refresh the pertinent web page to check for the added information. Alternatively, web server 22 may notify the ip buyer, via email or page, when the information has been added. After an evaluation period, if any, has elapsed, web server 22 generates an active bid page that can be accessed by ip sellers and opens the bidding process, as indicated by block 58 . Again, web server 22 can be configured to notify interested ip buyers when bidding opens. During the bidding process, web server 22 accumulates bids from ip buyers, as indicated by block 60 , and posts the current high bid on the active bid page accessed by the ip buyers, as indicated by block 61 . Web server 22 continuously accepts bids, as indicated by loop 62 , until the bid period elapses, as indicated by block 64 . At that time, the ip buyer with the highest bid generally will be awarded the transfer item subject to the basic terms specified by the ip seller. Alternatively, the ip seller may reserve the right to select a lower bid. Upon selection of a bid by the ip seller, web server 22 sends a notification to the ip buyer that submitted the bid. FIG. 17 is a flow diagram illustrating packaging of transfer items by an individual ip seller. As shown in FIG. 17 , an ip seller may submit a packaging request to web server 22 , as indicated by block 66 . In response, web server 22 generates a series of web pages that prompt the ip seller for identification of particular transfer items to be packaged. As indicated by block 68 , web server 22 then displays the pending transfer items. In particular, web server 22 may display the pending transfer items for the respective ip seller, and permit “check-box” selection of individual items for packaging, as indicated by block 70 , and as described with reference to FIG. 12 . Following selection, web server 22 may link the transfer item records in database 26 associated with the specified transfer items, as indicated by block 72 . For example, web server 22 may associate the records in the tables maintained by database server 24 . Next, the ip seller enters terms for the transfer of the package of transfer items, as indicated by block 74 . In response to requests from ip buyers, web server 22 then posts information for the packaged bid items together. In this manner, the packaged bid items can be displayed together on a single web page for evaluation by bidders. FIG. 18 is a flow diagram illustrating pooling of transfer items by two or more individuals. System 10 may allow ip sellers to pool their transfer items with one another, increasing the volume and scope of an overall ip offering. To enable pooling of bids, particular ip sellers may agree to exchange information for review purposes, e.g., by allowing access to transfer item records contained in database 26 . For example, two or more different universities may agree to exchange information in a particular technology area for purposes of obtaining bids intellectual property assets directed to related technologies. In many cases, an extensive information exchange will not be necessary. Web server 22 may be arranged to generate a web page for all ip sellers that sets forth a directory of ip sellers who are amenable to pooling. Upon identification of one or more different ip sellers for potential pooling, an ip seller submits a proposed transfer item pooling request to web server 22 , as indicated by block 76 . In response, web server 22 generates a message, e.g., an email or posting to a web page, that communicates the request to the prospective pooling seller, as indicated by block 78 , which requests that the prospective pooling seller indicate whether there is any potential interest, as indicated by block 80 . In the event the message is posted to a web page, it may be posted, for example, to a user account web page that the ip seller visits on a frequent basis. Along with the message, web server 22 includes preliminary information concerning the proposed pool such as the particular transfer items implicated by the pool. If the prospective pooling seller declines the proposed pool, as indicated by block 90 , web server 22 terminates the process and posts the transfer items individually. If the prospective pooling seller expresses preliminary interest, however, web server 11 may transmit a set of preliminary transfer terms, as indicated by block 82 . Web server 22 may give the prospective pooling seller the opportunity to modify the terms, as indicated by block 84 , in which case the modified terms are then transmitted to the other party, as indicated by loop 86 . This process may continue via the infomediary, e.g., by email or web page posting, or by more conventional means such as telephone discussions. In any event, the process continues until the parties have no further modifications and the pool is accepted, as indicated by block 88 . In particular, the web site may provide a group of form agreements that govern the rights of pooling parties relative to one another. Alternatively, the parties may formulate their own agreement, which can be executed in advance of the offer or bidding process or following transfer. Of course, the parties may be unable to reach an agreement, and ultimately may decline the pool. If the pool is accepted, however, web server 22 interacts with database server 24 to associate the pertinent transfer item records in database 26 as a pool. Web server 22 subsequently generates a web page for review by ip buyers that contains links to the pooled transfer items. The ip seller submitting the chosen bid is then entitled to transfer of the all of the pooled transfer items. FIG. 19 is a flow diagram illustrating pooling of bids by two or more ip buyers. System 10 may permit ip buyers to pool bids with respect to an individual transfer item or transfer item package or pool. When a large package or pool of transfer items is posted for bidding, smaller companies may pool their bids even if their individual resources are insufficient to take on the entire package or pool. With bid pooling, smaller buyers can obtain access to larger or more valuable intellectual property assets provided they can reach agreement concerning allocation or sharing of the resultant rights. When the companies desire to manufacture different components of an overall product, for example, access to applicable intellectual property rights can be mutually beneficial. In this manner, smaller or more narrowly focused companies can compete with larger, more diversified companies. Web server 22 may facilitate the bid pooling process by providing a communication mechanism between prospective bid poolers. When web server 22 receives a proposed bid pooling request from an ip buyer, as indicated by block 92 , it forwards the request to other ip buyers identified in the request, as indicated by block 94 . This process may take place via email communication, posting to a web page, or other means. The ip buyer may, for example, identify one or more other buyers for bid pooling. In most cases, the ip buyer will identify a particular transfer item, package, or pool to which the pooled bids will be directed. In other words, the ip buyers ordinarily will not pool bids for all transfer items, but rather target their pooled bids toward transfer items that are attractive to all pooling parties. If the proposed bid pooling is not accepted by any of the ip buyers, as indicated by block 96 , the pooled bid is declined by web server 22 , as indicated by block 98 . If the proposed pooling is accepted, however, web server 22 records the pool. Then, during the auction process, web server 22 sums the individual bids submitted by the pooling bidders, as indicated by block 100 , to produce an aggregate bid. During the auction process, this aggregate bid is compared to other bids to determine which is highest. Alternatively, the pooling bidders may elect one of the bidders to submit a collective bid for the entire pool. In either case, the parties in the bid pool take the transfer item together and must arrive at terms for disposition of the item among them following the auction. This process, also, can be facilitated via the web-based infomediary. Again, the web site may provide a group of form agreements that govern the rights of pooling parties relative to one another. Alternatively, the parties may formulate their own agreement. FIG. 20 is a flow diagram illustrating a process for a modification of terms or donation of a transfer item. In the event a particular transfer item does not entertain sufficient offers or bids during an initial offer or auction period, the web site may provide a mechanism that automatically reduces the opening offer price of minimum bid price of the transfer item, or ultimately facilitates donation of the item to a charitable organization for purposes of obtaining a tax benefit. In the example of FIG. 20 , a counter N is set to zero, as indicated by reference numeral 102 , prior to the open of bidding, as indicated by block 104 . As web server 22 accumulates bids, as indicated by block 106 , it is periodically determined whether an applicable bid period has elapsed, as indicated by block 107 . The bid period may run for a period of weeks or days, for example, and can specified by the ip seller. If the bid period has not elapsed, web server 22 continues to accumulate bids, as indicated by loop 108 and block 106 . Once the bid period elapses, however, web server 22 determines whether a sufficient bid has been submitted, as indicated by block 110 . A sufficient bid would be a bid that, for example, meets or exceeds an applicable minimum bid or offer prices. If a sufficient bid has been submitted, the highest bid can be accepted, as indicated by block 112 . Alternatively, the ip seller may choose one of the lower bids, if there are several, based on other considerations. If the bid period has elapsed and no sufficient bids have been submitted, the counter N is incremented, as indicated by block 114 . Value M is indicative of the maximum number of price reductions and resultant additional auction periods desired by the ip seller. If counter N does not exceed value M (block 116 ), web server 22 reduces the minimum bid or offer price of the transfer item, as indicated by block 118 , with the objective of attracting additional bids in a new auction or offer period. The reduction may be automatic and predetermined by the ip seller. Alternatively, the ip seller may be contacted in advance of each reduction. Upon reduction of the minimum offer or bid, the bid period is reset, as indicated by block 120 . Then, as indicated by loop 122 , a new period is opened, and the process is repeated. After the number of bid periods indicated by counter N has exceeded value M, and solicitation of acceptable bids or offers has been unsuccessful, the transfer item is simply designated for donation to a charitable organization, as indicated by block 124 . Thus, in the event no acceptable offers or bids are collected within a period of time, which may include multiple reductions in price, web server 22 may automatically record a donation of the rights to a charitable organization. Web server 22 may automatically generate appropriate paperwork for the owner and charitable organization for signature, either manual or electronic, and thereby document the transfer and issue a receipt. Some ip sellers may elect to bypass an offer or auction process, and simply donate the assets electronically, given the convenience provided by system 10 . The fair market value of the donated rights can be determined by staff associated with the web site administrator or agreed upon by the ip seller and the charitable organization. The ip seller may select the charitable organization in advance, e.g., by radio button selection from a list of several charitable organizations. Alternatively, designation of the charitable organization may be left to the system administrator. In any event, system 10 provides a convenient mechanism for deriving tax benefits from intellectual property assets, or other types of assets such as real and personal property, financial instruments, agreements, and the like. Disposal of the asset by the charitable organization then can be facilitated by system 10 , e.g., by designating the assets for a “clearance” or “fire sale” auction. FIG. 21 is a flow diagram illustrating operation of a transactional blind process. This feature will be desirable for parties who seek access to particular intellectual property assets, but wish to avoid tipping of the intellectual property owner as to a potential infringement. Instead, this feature may provide a preliminary mechanism for ascertaining the posture of an intellectual property owner with respect to the granting of licenses or other interests. Upon receipt of a request from a transaction blind, as indicated by block 126 , web server 22 may require input of information by the requester. As indicated by block 128 , for example, web server 22 ordinarily will require input of asset information identifying the asset, e.g., by patent number, registration number, or other description, and the party believed to be the owner of the asset. Further, as indicated by block 130 , web server 22 may require a set of proposed terms for transfer of an interest in the asset, e.g., nonexclusive license, exclusive license, or assignment, along with a proposed royalty or payment structure, and fields of use, if applicable. In some cases, the ip buyer may elect to forego terms. Following entry of the necessary information, web server 22 generates a message by which the proposed transaction is transmitted to the intellectual property owner, e.g., by email, web page posting, or other means, as indicated by block 132 . The intellectual property owner is advised to respond in the event there is preliminary interest (block 134 ) in discussing the proposed transaction. If the intellectual property owner expresses preliminary interest, proposed terms for the transaction are provided, as indicated by block 136 . If the intellectual property owner, based on the proposed terms, expresses further interest (block 138 ), the parties may initiate face-to-face negotiations, as indicated by block 140 . At this time, the identity of the prospective ip buyer typically will be disclosed, and the parties will proceed with negotiation via email, chat facility, telephone, or otherwise. If the intellectual property owner expresses no interest, either preliminary or following review of the proposed terms, the proposed transaction is declined, as indicated by block 142 . Advantageously, if the transaction is declined at either of the first two stages, the identity of the prospective ip buyer is never revealed. FIG. 22 is a block diagram illustrating a system for uploading of information pertinent to an intellectual property asset from a client to an infomediary 27 . In the system shown in FIG. 22 , ip sellers may submit transfer item information to web server 22 via a web browser. In particular, clients may submit individual transfer items and packages by navigating a series of web pages generated by web server 22 for submission of the necessary information. Alternatively, submission of transfer item information can be conducted on a more systematic basis. As shown in FIG. 22 , for example, clients can be equipped with an internal intranet system 162 that includes one or more client computers 166 , 168 with web browsers and an asset control center application 164 that collects transfer item information from intranet users, maintains and updates the information, and uploads information to infomediary 27 on an automated basis. With further reference to FIG. 22 , bid infomediary may include not only web server 22 for interaction with clients via http protocol, but also an ftp server 160 for automated interaction with asset control center 164 . Each server 22 , 160 interacts with database server 24 to add or modify information for the bid process. Asset control center 164 may include an intranet server that generates web pages for viewing by users situated at computers 166 , 168 . For submission of transfer items, for example, the intranet server may generate web pages analogous to those generated by web server 22 for submission of transfer items via the internet. Asset control center 164 also includes a database, database server, and file server for local storage of the information submitted by the client's individual users. On a regular basis, or as directed by a client user, asset control center 164 opens an ftp session with ftp server 160 to transfer new transfer item information or update or supplement transfer item information previously uploaded to the ftp server. On the basis of the uploaded information, infomediary 27 creates or updates transfer item records defining bid items. Thus, intranet system 162 and asset control center 164 provide a systematic mechanism for uploading information for several transfer items en masse or for individual transfer items on a selective basis. One advantage of this approach is that the transfer item information may be maintained by asset control center 164 for other reasons than entering the auction or offer process. In particular, a larger body of transfer item information may be accessed by client users for purposes of docketing, portfolio management, planning and the like. Selected transfer items then may be earmarked by ip sellers for submission to the auction or offer process. As further shown in FIG. 22 , along with intranet access and ftp uploads, ip sellers still may have the option of submitting transfer item information to web server 22 via the internet. FIG. 23 is a block diagram illustrating a system 200 for identifying parties in possession of potential transfer items. To increase the number of available transfer items, the web site can be integrated with an automated search mechanism that actively seeks intellectual property rights that may be ripe for transfer. As shown in FIG. 23 , the search mechanism may constitute a web crawler that monitors publicly accessible resources on the network that are likely to yield information concerning distressed assets. System 200 may include a system executive 202 , a user interface 204 , one or more collection controllers 206 , and a search controller 208 . Collection controller 206 spawns one or more web crawlers 210 , whereas search controller 208 spawns one or more search instances 212 . A database manager 214 is provided for storage and retrieval of information obtained via the searches. A notification module 216 transmits a message to the owner of a distressed asset, advising the owner of the services available via system the web-based infomediary provided by system 10 . System executive 202 is responsible for overall control and management of system 200 . Upon initial execution of system 200 , system executive 202 starts execution and instantiates database manager 214 for managing all accesses to a database. In one embodiment, database manager 214 has its own thread of execution. Preferably, database manager 214 has a client/server interface whereby other components of software system 200 initiate a remote procedure call in order to access the data of a database. In this manner, all accesses of the database are synchronized and inherently thread safe. Upon instantiating database manager 214 , system executive 202 commands database manager 214 to retrieve configuration data from a database. Typical configuration data includes a maximum number of concurrent collection controllers 206 that may be instantiated concurrently, a maximum number of concurrent web crawlers 210 and a maximum number of concurrent search instances 212 . System executive 202 waits for a control message, which can be issued in two ways. First, user interface 204 presents a graphical interface by which an operator controls software system 200 . After receiving input from the operator, user interface 204 communicates a control message to system executive 202 . Second, software system 200 may include a timer thread that awakens at user-configurable times and sends control messages to system executive 202 , thereby triggering automatic execution of software system 200 . In either case, system executive 202 retrieves information concerning the network resources that are to be analyzed. More specifically, the database of software system 200 stores a plurality of resource identifiers, each identifier corresponding to a resource residing on the global computer network. In one embodiment, the database stores a plurality of domains for monitoring. Each domain identifies a website of a company, government body or other organization, and is selected on the basis of content that is likely to identify parties in possession of distressed assets or in parties in precarious financial states. System executive 102 instantiates one or more collection controllers 206 , each of which traverse a respective network resource and develop a list of links defined by the resource. For each link, a collection controller 206 instantiates a web crawler 210 that traverses the information designated by the link and retrieves its content. Following retrieval of the content, search controller 208 instantiates a search instance 212 in which the parameters of a search defined by the user are applied to the content. The search parameters may be as simple as a list of parties declaring bankruptcy. Other searches may be more sophisticated, targeting particular industries, technologies, and business sectors. Upon identification of a party in possession of distressed assets or a party who has recently declared bankruptcy, notification module 216 may automatically, or at user instruction, send a message to the party advising it of the services available via system 10 . In this manner, system 200 can be exploited to pull potential ip sellers toward system 10 . The foregoing detailed description has been provided for a better understanding of the invention and is for exemplary purposes only. Modifications may be apparent to those skilled in the art without deviating from the spirit and scope of the claims.

A system and method provide a web-based infomediary for dissemination of intellectual property transfer information among multiple users via a global computer network such as the World Wide Web. The system and method can be used to provide network users with information to facilitate transfer of intellectual property rights by assignment or license. Also, the system and method can be configured to collect bids and offers from parties seeking to acquire rights, or conduct a web-based auction. In this manner, the system and method provide a web-based infomediary in the sense that they facilitate person-to-person or business-to-business online exchanges that leverage the Internet to unite buyers and sellers into a single, efficient virtual marketplace that provides a concentration of pertinent information.

This is a divisional of U.S. application Ser. No. 08/013,801, filed Feb. 2, 1993, now U.S. Pat. No. 5,420,019. BACKGROUND OF THE INVENTION The present invention provides novel bactericidal/permeability-increasing protein products and stable pharmaceutical compositions containing the same. Lipopolysaccharide (LPS), is a major component of the outer membrane of gram-negative bacteria and consists of serotype-specific O-side-chain polysaccharides linked to a conserved region of core oligosaccharide and lipid A. Raetz, Ann. Rev. Biochem., 59:129-170 (1990). LPS is an important mediator in the pathogenesis of gram-negative septic shock, one of the major causes of death in intensive-care units in the United States. Morrison, et al., Ann. Rev. Med. 38:417-432 (1987). LPS-binding proteins have been identified in various mammalian tissues. Morrison, Microb. Pathol., 7:389-398 (1989); Roeder, et al., Infect., Immun., 57:1054-1058 (1989). Among the most extensively studied of the LPS-binding proteins is bactericidal/permeability-increasing protein (BPI), a basic protein found in the azurophilic granules of polymorphonuclear leukocytes. Human BPI protein has been isolated from polymorphonuclear neutrophils by acid extraction combined with either ion exchange chromatography Elsbach, J. Biol. Chem., 254:11000 (1979)! or E. coli affinity chromatography Weiss, et al., Blood, 69:652 (1987)! and has potent bactericidal activity against a broad spectrum of gram-negative bacteria. While the BPI protein is cytotoxic against many gram-negative bacteria, it has no reported cytotoxic activity toward gram-positive bacteria, fungi, or mammalian cells. The amino acid sequence of the entire human BPI protein, as well as the DNA encoding the protein, have been elucidated in FIG. 1 of Gray, et al., J. Biol. Chem., 264:9505 (1989), incorporated herein by reference (SEQ ID NOs: 1 and 2). The Gray et al. publication discloses the isolation of human BPI-encoding cDNA from a cDNA library derived from DMSO-induced cells of the human promyelocytic leukemia HL-60 cell line (ATTC CCL 240). Multiple PCR amplifications of DNA from a freshly prepared cDNA library derived from such DMSO-induced HL-60 cells have revealed the existence of human BPI-encoding cDNAs wherein the codon specifying valine at amino acid position 151 is either GTC (as set out in SEQ ID No: 1) or GTG. Moreover, cDNA species employing GTG to specify valine at position 151 have also been found to specify either lysine (AAG) for the position 185 amino acid (as in SEQ ID Nos: 1 and 2) or a glutamic acid residue (GAG) at that position. A proteolytic fragment corresponding to the N-terminal portion of human BPI holoprotein possesses the antibacterial efficacy of the naturally-derived 55 kDa human BPI holoprotein. In contrast to the N-terminal portion, the C-terminal region of the isolated human BPI protein displays only slightly detectable antibacterial activity. Ooi, et al., J. Exp. Med., 174:649 (1991). A BPI N-terminal fragment, comprising approximately the first 199 amino acids of the human BPI holoprotein, has been produced by recombinant means as a 23 kD protein. Gazzano-Santoro et al., Infect. Immun. 60:4754-4761 (1992). The projected clinical use of BPI products for treatment of gram-negative sepsis in humans has prompted significant efforts to produce large quantities of recombinant BPI (rBPI) products suitable for incorporation into stable, homogeneous pharmaceutical preparations. For example, co-owned, co-pending U.S. patent application Ser. No. 07/885,501 by Grinna discloses novel methods for the purification of recombinant BPI products expressed in and secreted from genetically transformed mammalian host cells in culture. Efficacy of the purification processes is therein demonstrated in the context of products of transformed CHO cells which express DNA encoding the 31 amino acid "leader" sequence of human BPI and the initial 199 amino terminal residues of the mature protein (i.e. corresponding to the amino acids -31 through 199 of SEQ ID NO: 2). Co-owned, co-pending U.S. patent application Ser. No. 07/885,911 by Theofan, et al. is directed to novel, recombinant-produced BPI protein analog products resulting from the expression of DNA encoding the BPI leader sequence and either 191 or 199 amino terminal residues of human BPI fused to DNA encoding a constant region of an immunoglobulin heavy chain. Efforts to produce pharmaceutical grade BPI products for treatment of gram negative sepsis in humans have not yielded uniformly satisfactory results. A principal reason for this is the nature of the amino acid sequence of human BPI and the nature of the recombinant host cell environment in which the products are produced. As one example, biologically-active rBPI products comprising the initial 199 residues of BPI rBPI(1-199)! produced as secretory products of transfected CHO host cells may be purified in good yields. However, the isolated BPI products initially include dimeric forms of BPI as well as cysteine adduct species. Moreover, BPI products may be unstable upon storage at physiological temperature and pH, resulting in the formation of additional dimeric and adduct species. Such dimeric and adduct species, while retaining biological activity, are not preferred for incorporation into pharmaceutical preparations projected for human use. Dimer formation and the formation of cysteine adducts are the probable result of the fact that BPI includes three cysteine amino acid residues, all of which are positioned within the biologically active amino terminal region of BPI, i.e., at positions 132, 135 and 175. Formation of a single disulfide bond between two of the three cysteines allows for dimer formation or formation of cysteine adducts with the remaining free cysteine in the host cell cytoplasm and/or the cell culture supernatant. Even monomeric rBPI products display varying degrees of microheterogeneity in terms of the number of carboxy terminal residues present in such products. For example, it is difficult to detect full-length expression product in a medium containing host cells transformed or transfected with DNA encoding rBPI(1-199). Instead, the expression products obtained from such cells represent an heterogeneous array of carboxy-terminal truncated species of the rBPI N-terminal fragment. In fact, the expected full-length product (1-199) is often not detected as being among the rBPI species present in that heterogeneous array. Heterogeneity of the carboxy terminal amino acid sequence of rBPI(1-199) products appears to result from activity of carboxypeptidases in host cell cytoplasm and/or culture supernatant. An additional problem encountered in the preparation of pharmaceutical-grade BPI products is the formation of macroscopic particles which decrease the homogeneity of the product, as well as decreasing its activity. A preferred pharmaceutical composition containing rBPI products according to the invention comprises the combination of a poloxamer (polyoxypropylene-polyoxyethylene block copolymer) surfactant and a polysorbate (polyoxyethylene sorbitan fatty acid ester) surfactant. Such combinations are taught in co-owned, U.S. patent application, Ser. No. 08/190,869, now U.S. Pat. No. 5,488,034, to have synergistic effects in stabilizing pharmaceutically-active polypeptides against particle formation. Most preferred is a composition in which the rBPI product is present in a concentration of 1 mg/ml in citrate buffered saline (0.02 M citrate, 0.15 M NaCl, pH 5.0) comprising 0.1% by weight of poloxamer 188 (Pluronic F-68, BASF Wyandotte, Parsippany, N.J.) and 0.002% by weight of polysorbate 80 (Tween 80, ICI Americas Inc., Wilmington, Del.). There continues to be a need in the art for improved rBPI products suitable for incorporation into stable homogeneous pharmaceutical preparations. Such products would ideally be obtainable in large yield from transformed host cells, would retain the bactericidal and LPS-binding biological activities of BPI, and would be limited in their capacity to form dimeric species and cysteine adducts, and would be characterized by limited variation in carboxy termini. SUMMARY OF THE INVENTION The present invention provides novel, biologically-active, recombinant-produced BPI ("rBPI") protein and protein fragment products which are characterized by a resistance to dimerization and cysteine adduct formation, making such products highly suitable for pharmaceutical use. Also provided are rBPI products characterized by decreased molecular heterogeneity at the carboxy terminus. Novel DNA sequences encoding rBPI products and analog products, plasmid vectors containing the DNA, host cells stably transformed or transfected with the plasmids, recombinant preparative methods, stable pharmaceutical compositions and treatment methods are also provided by the invention. According to one aspect of the present invention, rBPI protein analogs are provided which comprise a BPI N-terminal fragment wherein a cysteine at amino acid position 132 or 135 is replaced by another amino acid, preferably a non-polar amino acid such as serine or alanine. In a preferred embodiment of the invention, the cysteine residue at position 132 of a polypeptide comprising the first 199 N-terminal residues of BPI is replaced by an alanine residue in a recombinant product designated "rBPI(1-199)ala 132 ". Also in a preferred embodiment of the invention, the cysteine at position 135 of a BPI fragment comprising the first 199 N-terminal BPI residues is replaced by a serine, resulting in a recombinant product designated "rBPI(1-199)ser 135 ". Highly preferred is a recombinant product designated "rBPI(1-193)ala 132 " which is characterized by decreased heterogeneity in terms of the identity of its carboxy terminal residue. Also in a preferred embodiment of the invention, a polypeptide is taught which comprises the first 193 amino-terminal residues of BPI and which has a stop codon immediately following the codon for leucine at position 193. According to another aspect of the invention, DNA sequences are provided which encode the above-described rBPI protein and protein fragment products, including analog products. Such DNA sequences may also encode the 31-residue BPI leader sequence and the BPI polyadenylation signal. Also provided are autonomously-replicating DNA plasmid vectors which include DNA encoding the above-mentioned products and analogs as well as host cells which are stably transformed or transfected with that DNA in a manner sufficient to allow their expression. Transformed or transfected host cells according to the invention are of manifest utility in methods for the large-scale production of rBPI protein products of the invention. The invention also contemplates rBPI protein analog products in the form of fusion proteins comprising, at the amino terminal, rBPI protein analog products of the invention and, at the carboxy terminal, a constant region of an immunoglobulin heavy chain or an allelic variant thereof. Natural sequence BPI/immunoglobulin fusion proteins are taught in the co-pending, co-owned U.S. patent application Ser. No. 07/885,911 by Theofan, et al., the disclosures of which are incorporated herein by reference. The invention further contemplates methods for producing the aforementioned fusion proteins. Also within the scope of the present invention are DNA sequences encoding biologically-active rBPI protein fragment products having from about 176 to about 198 of the N-terminal amino acids of BPI. These DNAs allow for production of BPI products in eukaryotic host cells, such as CHO cells, wherein the products display less heterogeneity in terms of the carboxy terminal residues present. Presently preferred are DNAs encoding 193 N-terminal residues of BPI (e.g., DNAs encoding the thirty-one amino acid leader sequence of BPI, the initial 193 N-terminal amino acids, and one or more stop codons). Most preferred are such DNAs which additionally encode proteins wherein the cysteine at either position 132 or 135 is replaced (e.g, rBPI(1-193)ala 132 ). Finally, the present invention also provides stable, homogeneous pharmaceutical compositions comprising the rBPI protein products of the invention in pharmaceutically acceptable diluents, adjuvants, and carriers. Such pharmaceutical compositions are resistant to the formation of rBPI product particles. Such compositions are useful in the treatment of gram-negative bacterial infection and the sequelae thereof, including endotoxin-related shock and one or more conditions associated therewith, such as disseminated intravascular coagulation, anemia, thrombocytopenia, leukopenia, adult respiratory distress syndrome, renal failure, hypotension, fever, and metabolic acidosis. Numerous additional aspects and advantages of the invention will become apparent to those skilled in the art upon considering the following detailed description of the invention which describes presently preferred embodiments thereof. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 represents results of SDS-PAGE analysis of rBPI(1-199) products. FIGS. 2A and 2B represents results of SDS-PAGE analysis of rBPI(1-193) and rBPI(1-199)ala 132 products. FIG. 3 depicts results of cation exchange HPLC analysis of rBPI(1-199) products. FIG. 4 shows results of cation exchange HPLC analysis of rBPI(1-199)ala 132 products. FIG. 5 represents results of reverse phase HPLC run on rBPI(1-199) products. FIG. 6 represents results of reverse phase HPLC run on rBPI(1-199)ala 132 products. FIG. 7 presents results of turbidity studies on pharmaceutical compositions containing rBPI products with and without poloxamer/polysorbate surfactant ingredients at pH 7.0 and 57° C. DETAILED DESCRIPTION The following detailed description relates to the manufacture and properties of various rBPI product preparations which comprise an amino acid substitution at a cysteine residue and/or highly uniform carboxy termini. More specifically, Example 1 relates to an exemplary means by which base substitutions are introduced in the nucleotide sequence encoding an exemplary N-terminal fragment of the BPI protein and to the incorporation of such mutated sequences into plasmid vectors. Example 2 addresses the incorporation of vectors of Example 1 into appropriate host cells and further describes the expression of recombinant BPI protein polypeptide products of the invention. Example 3 relates to construction of DNAs encoding cysteine replacement analog products of the invention and the use thereof in in vitro transcription/translation procedures. Example 4 relates to properties of rBPI product polypeptides of the invention. EXAMPLE 1 Construction Of Vectors Containing BPI Cysteine Replacement Analogs A. Construction Of Plasmids pING4519 And pING4520 The expression vector, pING4503, was used as a source of DNA encoding a recombinant expression product designated rBPI(1-199), i.e., encoding a polypeptide having the 31-residue signal sequence and the first 199 amino acids of the N-terminus of the mature human BPI, as set out in SEQ ID NOs: 1 and 2 except that valine at position 151 is specified by GTG rather than GTC and residue 185 is glutamic acid (specified by GAG) rather than lysine (specified by AAG). Plasmid pING4503 has been described in co-pending, co-owned U.S. patent application Ser. No. 07/885,911 by Theofan, et al. which is incorporated herein by reference with respect to the background of the invention. Briefly, the construction of pING4503 is based on plasmid pING2237N which contains the mouse immunoglobulin heavy chain enhancer element, the LTR enhancer-promoter element from Abelson murine leukemia virus (A-MuLv) DNA, the SV40 19S/16S splice junction at the 5' end of the gene to be expressed, and the human genomic gamma-1 polyadenylation site at the 3' end of the gene to be expressed. Plasmid pING2237N also has a mouse dihydrofolate reductase (DHFR) selectable marker. The DNA encoding rBPI(1-199), including 30 bp of the natural 5' untranslated region and bases encoding the 31 amino acid signal sequence, as well as 199 N-terminal amino acids of BPI, is inserted between unique SalI and SstII restriction sites in pING4503. Two vectors, pING4519 and pING4520, were constructed based on pING4503 for expression of rBPI(1-199) cysteine replacement analogs in which one of the three naturally-occurring cysteine residues of BPI was replaced with another amino acid. A PvuII site (CAGCTG) which occurs only once in the DNA encoding rBPI(1-199), and which is located between cysteine 132 and cysteine 135, was utilized in these constructions. Because several additional PvuII sites exist in pING4503, it was first necessary to isolate the SalI-SstII fragment which contained the insert encoding rBPI(1-199) from pING4503 by digesting with SalI and SstII. The purified SalI-SstII rBPI(1-199) insert was then digested with PvuII, resulting in an approximately 529 bp SalI-PvuII fragment and an approximately 209 bp PvuII-SstII fragment, each of which was purified separately. Plasmid pING4519 is identical to pING4503 except that pING4519 contains a DNA insert encoding an rBPI(1-199) in which a codon for alanine is substituted for the codon specifying the native cysteine at position 132. As noted above, the recombinant product resulting from host cell expression and secretory processing of such an insert is referred to as "rBPI(1-199)ala 132 ". In order to generate pING4519, BPI DNA sequences were PCR amplified from pING4503 using the primers BPI-6: AAGCTTGTCGACCAGGCCTTGAGGT (SEQ ID NO: 3), which incorporated a SalI restriction site at the 5' end of the 30 bp BPI untranslated region, and BPI-14: CTGGAGGCGGTGATGGTG (SEQ ID NO: 4), which incorporated one half of the PvuII site and the base substitutions necessary to code for alanine at position 132. PCR amplification was accomplished using the GeneAmp PCR kit (Perkin Elmer Cetus, Norwalk, Conn.) according to the manufacturer's instructions. The resulting PCR fragment was digested with SalI, resulting in an approximately 529 bp SalI-blunt fragment which was then used in a three-piece ligation, together with the approximately 209 bp PvuII-SstII fragment described above and the large fragment resulting from SalI and SstII digestion of pING4503, to generate pING4519. Plasmid pING4520 is identical to pING4519 with the exception that pING4520 contains a DNA insert encoding an rBPI(1-199) analog in which a serine codon is substituted for the codon specifying the native cysteine at position 135. As noted above, the recombinant product resulting from host cell expression of such an insert is designated "rBPI(1-199) ser 135 ". In order to generate pING4520, BPI DNA sequences were PCR amplified from pING4513, a plasmid essentially similar to pING4503 except that the selection marker is gpt instead of DHFR and the cDNA insert encodes the signal sequence and full-length BPI (456 residues) instead of only the rBPI(1-199) portion. Amplification by PCR was accomplished using primer BPI-15: CTCCAGCAGCCACATCAAC (SEQ ID NO: 5), wherein the 5' end incorporates one half of a mutated PvuII site (wherein "CTG" is changed to "CTC") and the base substitutions necessary to code for serine at position 135; and primer BPI-7: GAACTTGGTTGTCAGTCG (SEQ ID NO: 6), representing rBPI-encoding sequences located downstream of the region encoding BPI residue 199. This PCR fragment was digested with BstBI, which cuts downstream of the cysteine 135 mutagenesis site, and the resulting approximately 100 bp blunt-BstBI fragment was gel purified. A three piece ligation was then performed with the 529 bp SalI-PvuII BPI restriction fragment described above, the 100 bp blunt-BstBI fragment, and a large fragment resulting from BstBI-SalI digestion of pING4503, to generate pING4520. B. Construction Of Plasmid pING4530 Another vector, pING4530, was constructed which contained the alanine-for-cysteine replacement as in pING4519, but which contained the gpt selectable marker (allowing for mycophenolic acid resistance) instead of the DHFR marker earned over from pING4503 to pING4519. To construct pING4530, a 1629 bp SalI-DraIII restriction fragment was isolated from pING4519. This fragment included all of the rBPI(1-199)ala 132 coding region as well as an additional approximately 895 bp vector sequence at the 3' end of the coding region. This fragment was ligated to the large (approximately 7230 bp) DraIII-SalI vector fragment isolated from pING4513 to generate pING4530. C. Construction Of Plasmid pING4533 Plasmid pING4533 was constructed for expression of rBPI(1-199)ala 132 , wherein the codon specifying the fifth amino acid of the BPI signal sequence, methionine (ATG), at position -27 was placed in the context of the consensus Kozak translation initiation sequence GCCACCRCCATGG (SEQ ID NO: 7) Kozak, Nucl. Acid. Res., 15:8125 (1987)!, and in which the DNA sequence encoding the first 4 amino acids of the BPI signal was removed. This was accomplished by PCR amplification of BPI sequences from a plasmid containing the full length human BPI cDNA in pGEM-7zf(+)! using the PCR primer BPI-23: ACTGTCGACGCCACCATGGCCAGGGGC (SEQ ID NO: 8), incorporating a SalI restriction site and the nucleotides GCCACC in front of the ATG (methionine) at position -27 of the BPI signal, and the primer BPI-2: CCGCGGCTCGAGCTATATTTTGGTCAT (SEQ ID NO: 9), corresponding to the 3' end of the rBPI(1-199) coding sequence. The approximately 700 bp PCR amplified DNA was digested with SalI and EcoRI and the resulting 270 bp fragment, including approximately the first one-third of the BPI(1-199) coding sequence, was purified. This SalI-EcoRI fragment was ligated to 2 other fragments: (1) a 420 bp EcoRI-SstII fragment from pING4519, encoding the remainder of BPI(1-199) wherein alanine replaces cysteine at position 132; and (2) an approximately 8000 bp SstII-SalI vector fragment from pING4502 (a vector essentially similar to pING4503 except that it does not include the 30 bp 5' untranslated sequence and has a gpt marker rather than DHFR), to generate pING4533 which contains a gpt marker. D. Construction Of Plasmids pING4221, pING4222, And pING4223 Vectors similar to pING4533 were constructed having an insert which contained the optimized Kozak translation initiation site corresponding to methionyl residue -27 of the signal sequence, and an alanine-for-cysteine replacement at position 132. However, the BPI fragment coding sequence terminated at residue 193 in these constructions. As noted above, the recombinant product resulting from host cell expression of this DNA is referred to as "rBPI(1-193)ala 132 ". Vectors containing these inserts were made by first digesting pING4533 with SalI, which cuts at the 5' end of the BPI DNA insert, and AlwNI, which leaves a three bp 3'-overhang at residue 192. The resulting approximately 700 bp fragment was then purified. This fragment was re-ligated into the large fragment resulting from pING4533 digestion with SstII-SalI, along with two annealed complementary oligonucleotides, BPI-30: CTGTAGCTCGAGCCGC (SEQ ID NO: 10) and BPI-31: GGCTCGAGCTACAGAGT (SEQ ID NO: 11). This replaced the region between the AlwNI and SstII sites with the codon for residue 193 (leucine), a stop codon, and an XhoI restriction site 5' to the SstII site and resulted in regeneration of both the AlwNI and the SstII sites and placement of the stop codon, TAG, immediately after the codon (CTG) for amino acid 193 (leucine). The resultant plasmid was designated pING4223 and had the gpt marker. Similar constructions were made exactly as described for pING4223 except that different SstII-SalI vector fragments were used to generate vectors with different selection markers. For example, pING4221 is identical to pING4223 except that it contains the his marker (conferring resistance to histidinol) instead of gpt and pING4222 is identical to pING4223 except that it contains the DHFR marker instead of gpt. E. Construction Of Plasmids pING4537, pING4143, pING4146, pING4150, And pING4154 A series of vectors was constructed which contained an insert encoding rBPI(1-193)ala 132 , the optimized Kozak translation initiation site, and different selection markers essentially identical to those described with respect to pING4221, pING4222 and pING4223 except that the human genomic gamma-1 heavy chain polyadenylation and transcription termination region at the 3' end of the SstII site was replaced with a human light chain polyadenylation sequence followed by mouse light chain (kappa) genomic transcription termination sequences. In collateral gene expression studies, the light chain polyadenylation signal and transcription termination region appeared to be responsible for 2.5-5 fold increases in BPI expression levels in Sp2/0 and CHO-K1 cells. The aforementioned vectors were constructed by first constructing pING4537, a vector similar to pING4533 which contains the rBPI(1-199)ala 132 insert. However, pING4537 includes the human light chain polyadenylation sequences instead of the human heavy chain sequence. The mouse kappa 3' sequences were obtained from pING3170, an expression vector which encodes a human light chain cDNA and includes a mouse genomic light chain 3' transcription termination sequence. This was accomplished by digesting with SstI, which cuts 35 bp upstream of the mouse light chain stop codon, treating with T4 DNA polymerase to make the end blunt, then cutting with BamHI, and purifying an approximately 1350 bp fragment which includes the mouse kappa 3' sequences. The resulting fragment consists of approximately 250 bp of the 3' portion of the human light chain constant region cDNA and the polyadenylation signal followed by a BamHI linker as described in the construct called Δ8 in Lui et al., J. Immunol. 139:3521, (1987). The remainder of the approximately 1350 bp fragment consists of a BglII-BamHI mouse kappa 3' genomic fragment fragment "D" of Xu et al., J. Biol. Chem. 261:3838, (1986)! which supplies transcription termination sequences. This fragment was used in a 3-piece ligation with two fragments from pING4533: a 3044 bp fragment which includes all of BPI insert and part of vector obtained by digestion with SstII, T4 polymerase treatment, and NotI digestion (which includes all of BPI insert and part of vector), and an approximately 4574 bp BamHI-NotI fragment. The resulting vector, pING4537, is identical to pING4533 with the exception of the above-noted differences in the genomic 3' untranslated region. Additional vectors containing the kappa 3' untranslated sequences were constructed using pING4537 as the source of the kappa 3' fragment. The kappa 3' untranslated sequences were isolated by digestion of pING4537 with XhoI (a unique site which occurs immediately after the BPI stop codon) and BamHI. The resulting approximately 1360 bp XhoI-BamHI fragment was used in a series of 3-piece ligations to generate the following four vectors, all of which have inserts encoding rBPI(1-193)ala 132 and which have the optimized Kozak translation initiation site at residue -27 of the signal: (1) pING4143 (gpt marker), obtained by ligating a pING4223 4574 bp BamHI-NotI fragment (gpt marker), a pING4223 NotI-XhoI BPI insert-containing fragment of approximately 3019 bp, and the pING4537 XhoI-BamHI fragment; (2) pING4146 (DHFR marker), obtained by ligating a pING4222 approximately 4159 bp BamHI-NotI fragment (DHFR marker), a pING4223 NotI-XhoI BPI insert-containing fragment of approximately 3019 bp, and the pING4537 XhoI-BamHI fragment; (3) pING4150 (his marker), obtained by ligating a pING4221 his-containing approximately 4772 bp BamHI-NotI fragment, a pING4222 NotI-XhoI BPI insert-containing fragment, and the pING4537 XhoI-BamHI fragment; and (4) pING4154 (neo marker), obtained by ligating a pING3174 neo-containing approximately 4042 bp BamHI-BsaI fragment, a pING4221 BsaI-XhoI BPI insert-containing fragment of approximately 3883 bp and the pING4537 XhoI-BamHI fragment. Plasmid pING3174 contains an insert encoding antibody heavy chain DNA and has a neo marker. The neo gene and its flanking sequences were obtained from the pSv2 neo plasmid reported by Southern et al., J. Mol. Appl. Genet., 1:327 (1982). F. Construction Of Plasmids pING4144 And pING4151 Two plasmids were constructed, pING4144 and pING4151, which were identical to pING4143 and pING4150, respectively, except that expression of rBPI coding sequences was under control of the human cytomegalovirus (hCMV) immediate early enhancer/promoter instead of the Abelson murine leukemia virus (A-MuLv) LTR promoter. Therefore, both pING4144 and pING4151 contained the mutation of the cysteine at position 132 to alanine, the optimized Kozak translation initiation sequence, and the human light chain poly-A/mouse kappa genomic transcription termination region. The region between nucleotides 879 and 1708 of the original vectors (pING4143 and pING4150) was replaced with a region of the hCMV enhancer/promoter corresponding to nucleotides -598 through +174 as shown in FIG. 3 of Boshart et al., Cell 41:521 (1985), incorporated herein by reference. To introduce the hCMV promoter region into BPI expression vectors, plasmid pING4538 was first constructed by replacing the approximately 1117 bp EcoRI-SalI/A-MuLv promoter-containing fragment of pING4222 with an approximately 1054 bp EcoRI-SalI/hCMV promoter-containing fragment from plasmid pING2250 which contains the hCMV promoter driving expression of an antibody light chain insert. To construct pING4144, three fragments were ligated together: (1) the approximately 2955 bp rBPI(1-193)-containing NotI-XhoI fragment from pING4538; (2) the approximately 1360 bp XhoI-BamHI fragment from pING4537; and (3) the approximately 4770 bp BamHI-NotI fragment containing the his gene from pING4221. G. Construction Of Plasmids pING4145, pING4148, And pING4152 Plasmids pING4145, pING4148 and pING4152 were constructed and were identical to pING4143, pING4146, and pING4150, respectively, except that they contained the wild-type (natural sequence) cysteine at position 132 instead of an alanine substitution. Thus, all three contained the rBPI(1-193) insert, the optimized Kozak translation initiation sequence and the human light chain Poly A/mouse kappa genomic transcription termination region. These three plasmids were constructed as follows. To construct pING4145, three fragments were ligated together: (1) the approximately 3000 bp NotI-XhoI BPI(1-193) containing fragment from pING4140 (pING4140 is identical to pING4221 except that it contains the wild-type cysteine at position 132); (2) the approximately 1360 bp XhoI-BamHI fragment from pING4537; and (3) the approximately 4570 bp BamHI-NotI fragment containing the gpt gene from pING4223. To construct pING4148, three fragments were ligated together: (1) the NotI-XhoI fragment from pING4140; (2) the XhoI-BamHI fragment from pING4537; and (3) the approximately 4150 bp BamHI-NotI fragment containing the DHFR gene from pING4222. To construct pING4152, three fragments were ligated together: (1) the approximately 3000 bp NotI-XhoI fragment from pING4142 (pING4142 is identical to pING4293 except that it contains the wild-type cysteine at 132); (2) the XhoI-BamHI fragment from pING4537; and (3) the approximately 4770 bp BamHI-NotI fragment containing the his gene from pING4221. Table I, below, summarizes the content of the plasmids whose preparation is described in Sections A through G above. TABLE I______________________________________ SignalPlasmid BPI Product Seq. Marker 3' Terminal Promoter______________________________________pING4519 (1-199) 31AA DHFR* Human A-MuLv Ala.sup.132 Genomic HC Gamma-1 Poly-ApING4520 (1-199) 31AA DHFR* Human A-MuLv Ser.sup.135 Genomic HC Gamma-1 Poly-ApING4530 (1-199) 31AA gpt Human A-MuLv Ala.sup.132 Genomic HC Gamma-1 Poly-ApING4533 (1-199) Kozak gpt Human A-MuLv Ala.sup.132 initiation Genomic HC Seq; Gamma-1 27AA Poly-A signalpING4223 (1-193) Kozak gpt Human A-MuLv Ala.sup.132 initiation Genomic HC Seq; Gamma-1 27AA Poly-A signalpING4221 (1-193) Kozak his Human A-MuLv Ala.sup.132 initiation Genomic HC Seq; Gamma-1 27AA Poly-A signalpING4222 (1-193) Kozak DHFR Human A-MuLv Ala.sup.132 initiation Genomic HC Seq; Gamma-1 27AA Poly-A signalpING4537 (1-199) Kozak gpt Human A-MuLv Ala.sup.132 initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4143 (1-193) Kozak gpt Human A-MuLv Ala.sup.132 initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4146 (1-193) Kozak DHFR Human A-MuLv Ala.sup.132 initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4150 (1-193) Kozak his Human A-MuLv Ala.sup.132 initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4144 (1-193) Kozak gpt Human hCMV Ala.sup.132 initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4145 (1-193) Kozak gpt Human A-MuLv initiation Kappa Poly- seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4148 (1-193) Kozak DHFR Human A-MuLv initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4152 (1-193) Kozak his Human A-MuLv initiation Kappa Poly- Seq; A/Mouse 27AA Kappa Signal Genomic Transcription TerminationpING4151 (1-193) Kozak his Human hCMV ala.sup.132 initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription TerminationpING4154 (1-193) Kozak neo Human A-MuLv ala.sup.132 initiation Kappa Poly- Seq; A/Mouse 27AA Kappa signal Genomic Transcription Termination______________________________________ *An altered DHFR gene as described in copending, coowned U.S. Pat. application, Ser. No. 07/885,911, incorporated herein by reference. EXAMPLE 2 Transfection Of Cells For Expression Of The rBPI Cysteine Replacement Analogs Mammalian cells are preferred hosts for production of rBPI protein analogs according to the invention because such cells allow for proper secretion, folding, and post-translational modification of expressed proteins. Presently preferred mammalian host cells for production of analogs of the invention include cells of fibroblast and lymphoid origin, such as: CHO-K1 cells (ATCC CCL61); CHO-DG44 cells, a dihydrofolate reductase deficient DHFR - ! mutant of CHO Toronto obtained from Dr. Lawrence Chasin, Columbia University; CHO-DXB-11, a DHFR - mutant of CHO-K1 obtained from Dr. Lawrence Chasin; Veto cells (ATCC CRL81); Baby Hamster Kidney (BHK) cells (ATCC CCL10); Sp2/O-Ag14 hybridoma cells (ATCC CRL1581); and NSO myeloma (ECACC No. 85110503). Transfection of mammalian cells may be accomplished by a variety of methods. A common approach involves calcium phosphate precipitation of expression vector DNA which is subsequently taken up by host cells. Another common approach, electroporation, causes cells to take up DNA through membrane pores created by the generation of a strong electric field (Sambrook et al., Molecular Cloning, A Laboratory Manual, Cold Spring Laboratory Harbor Press, 16.30-16.31 (1989)!. Selection for transfected cells is facilitated by incorporation in the expression vector of a gene whose product allows the transfected cells to survive and grow under selective conditions. A number of such genes have been identified. These include, among others: (1) neo, a prokaryotic gene which encodes resistance to the aminoglycoside antibiotic G418; (2) E. coli guanine phoshporibosyl transferase (gpt), which encodes resistance to mycophenolic acid (MPA) in the presence of xanthine, Mulligan et al., Proc. Nat. Acad. Sci. USA, 78:2072-2076 (1981)!; (3) dihydrofolate reductase (DHFR), which allows for growth of DHFR - cells in the absence of nucleosides and gene amplification in the presence of increasing concentration of methotrexate; (4) the hisD gene of Salmonella typhimurium which allows growth in the presence of histidinol Hartman et al., Proc. Nat. Acad. Sci. USA, 85:8047-8051, (1988)!; (5) the trpB gene of E. coli Hartman et al., Proc. Nat. Acad. Sci. USA, 85:8047-8051, (1988)!, which allows growth in the presence of indole (without tryptophan); and (6) the glutamine synthetase gene, which allows growth in media lacking glutamine. The availability of these selective markers, either alone or in various combinations, provides flexibility in the generation of mammalian cell lines which express recombinant products at high levels. A. Transfection of CHO-K1 Cells with pING4533 Plasmid pING4533 contains gene sequences encoding rBPI(1-199)ala 132 fused to the A-MuLv promoter, the optimized Kozak translation initiation sequence, the human gamma-1 heavy chain 3' untranslated region, and the gpt marker for selection of MPA-resistant cells. The CHO-K1 cell line is maintained in Ham's F12 medium plus 10% fetal bovine serum (FBS) supplemented with glutamine/penicillin/streptomycin (Irvine Scientific, Irvine, Calif.). The cells were transfected by electroporation with 40 μg of pING4533 DNA which was first digested with NotI, extracted with phenol-chloroform and ethanol precipitated. Following electroporation, the cells were allowed to recover for 24 hours in non-selective Ham's F12 medium. The cells were then trypsinized, resuspended at a concentration of 5×10 4 cells/ml in Ham's F12 medium supplemented with MPA (25 μg/ml) and xanthine (250 μg/ml) and then plated at 10 4 cells/well in 96-well plates. Untransfected CHO-K1 cells are unable to grow in this medium due to the inhibition of pyrimidine synthesis by MPA. At 2 weeks, colonies consisting of transfected cells were observed in the 96-well plates. Supernatants from wells containing single colonies were analyzed for the presence of BPI-reactive protein by anti-BPI ELISA using rBPI(1-199) as a standard. In this assay, Immulon-II 96-well plates (Dynatech, Chantilly, Va.) were pre-coated with affinity purified rabbit anti-rBPI(1-199) antiserum. Supernatant samples were added and detection was carried out using affinity purified, biotinylated rabbit anti-rBPI(1-199) antiserum and peroxidase-labeled avidin. Approximately 800 colonies were screened in this manner. Thirty-one colonies having the highest production were transferred to 24-well plates for productivity assessment. Cells were grown to confluence in a 24-well plate in Ham's F12 medium supplemented with 10% FBS. Once the cells reached confluence, the Ham's F12 medium was removed and 1 ml of HB-CHO serum free medium (Irvine Scientific) plus 40 μl of sterile S-sepharose beads (Pharmacia, Piscataway, N.J.) was added as in co-owned, co-pending U.S. patent application Ser. No. 07/885,501 by Grinna. The cells were then incubated for 7 days after which the S-sepharose beads were removed and washed with 0.1 M NaCl in 10 mM Tris buffer (pH 7.5). The product was eluted from the beads by addition of 1.0 M NaCl in Tris buffer and quantitated by ELISA as described above. The top-producing transformant, designated A153, secreted approximately 3 μg/ml in this assay and was adapted to growth in Excell 301 serum-free medium (JRH Scientific, Lenexa, Kans.). The adapted cells were grown in 1.5L fermenters in Excell 301 medium in the presence of S-sepharose beads. Productivity was assessed at 120-140 hours by C4 HPLC analysis of product eluted from S-sepharose beads (50 ml aliquots). The productivity was 15-25 μg/L at these stages of the fermentation. B. Transfection Of CHO-DG44 Cells With pING4222 Plasmid pING4222 contains DNA encoding the rBPI(1-193)ala 132 analog fused to the A-MuLv promoter, optimized Kozak initiation sequence, human gamma-1 heavy chain 3' untranslated region, and the mouse DHFR gene for selection of transfected cells in a nucleoside-free medium. The cell line, CHO DG44, was maintained in Ham's F12 medium plus 10% FBS with glutamine/penicillin/streptomycin. The cells were transfected with linearized pING4222 DNA (40 μg digested with PvuI, phenol-chloroform extracted, ethanol precipitated) using the calcium phosphate method of Wigler, et al. Cell, 11:223 (1977). Following calcium phosphate treatment, the cells were plated in 96-well plates at approximately 10 4 cells/well and transfectants were obtained by growth in selective medium consisting of αMEM medium lacking nucleosides (Irvine Scientific) and supplemented with dialyzed FBS (100 ml serum dialyzed vs 4L cold 0.15M NaCl using 6000-8000 MW cutoff, 16 hours, 4° C.). Untransfected CHO-DG44 cells are unable to grow in this medium due to the DHFR mutation and the lack of nucleosides in the medium supplemented with dialyzed serum. At 2 weeks, each well contained approximately 2-3 colonies. The supernatants from wells of a 96-well plate were analyzed for the presence of rBPI(1-193) ala 132 by ELISA as in Section A. Twenty-four highest-producing clones were expanded into 24-well plates in selective αMEM medium supplemented with 0.05 μM methotrexate to induce gene amplification of the rBPI analog-encoding DNA. On observation of growth, cells were transferred to a new 24-well plate and productivity was assessed from S-sepharose eluates as described in section A for the pING4533/CHO-K1 transfectants. The five highest-producing clones were combined and subcloned by limiting dilution in 96-well plates. The supernatant wells containing single colonies were assayed for levels of rBPI(1-193)ala 132 by ELISA. Twenty highest-producing subclones were next expanded into 24-well plates and subjected to further amplification in the presence of 0.4 μM methotrexate and the levels of product expression for the amplified cells was determined by ELISA. The top producers, Clones 4, 75, and 80, secreted 25-37 μg/ml at 7 days in a 24-well plate containing S-sepharose. C. Transfection Of Sp2/O Cells With pING4223 And pING4221 A strategy adopted in an attempt to achieve optimal expression of desired rBPI products involved transfection of cells having a first expression plasmid with a first marker, screening for the highest producers, and then transfecting the same cells with a second expression plasmid having a different marker. This strategy is described below using Sp2/O cells. Plasmid pING4223 contains DNA encoding rBPI(1-193)ala 132 BPI fused to the A-MuLv promoter, optimized Kozak translation initiation sequence, human gamma-1 heavy chain 3' untranslated sequences, and the gpt marker for selection of MPA-resistant cells. The Sp2/O cell line was maintained in DMEM medium supplemented with 10% FBS with glutamine/penicillin/streptomycin. The Sp2/O cells were transfected by electroporation with 40 μg of pING4223 DNA which had been digested with NotI, extracted with phenol-chloroform and ethanol precipitated. Following electroporation, the cells were allowed to recover for 48 hours in non-selective DMEM medium. The cells were then centrifuged and resuspended at a concentration of 5×10 4 cells/ml in DMEM medium supplemented with MPA (6 μg/ml) and xanthine (250 μg/ml) and plated at 10 4 cells/well in 96-well plates. Untransfected Sp2/O cells are unable to grow in this medium due to the inhibition of pyrimidine synthesis by the MPA. At 1.5-2 weeks, colonies consisting of transfected cells were observed in the 96-well plates. Supernatants from wells containing single colonies were analyzed for the presence of product-reactive protein by ELISA. The highest producers were transferred to a 24-well plate and productivity was assessed in extinct 24-well cultures for cells grown in the presence and absence of 10 -7 M dexamethasone, which causes an increase in expression by the A-MuLv promoter as a result of interactions with the glucocorticoid receptor. The best producer, Clone 2×3, secreted approximately 3 μg/ml and 7 μg/ml in the absence and presence of dexamethasone, respectively. Clone 2×3 was next transfected by electroporation with pING4221, which contains the his gene for selection of transfectants. Following recovery for 48 hours in DMEM plus 10% FBS medium, the cells were plated in 96-well plates at approximately 10 4 cells/well in DMEM/FBS supplemented with 6 μg/ml MPA, 250 μg/ml xanthine and 8 mM histidinol. Untransfected cells were unable to grow in the presence of the histidinol and MPA. At 1.5-2 weeks, transfected cells were observed in the 96-well plates. Supernatants from wells containing single colonies were analyzed for the presence of rBPI-reactive protein by ELISA. The highest producers were transferred to a 24-well plate. Productivity was assessed as extinct 24-well cultures for cells grown in the presence and absence of 10 -7 M dexamethasone. The best producer, Clone 2×3-130, secreted approximately 15 μg/ml and 30 μg/ml in the absence and presence of dexamethasone, respectively. This isolate was next subcloned by limiting dilution in 96-well plates. Wells containing single colonies were screened by ELISA and the best producers were expanded and retested in 24 well cultures in the presence and absence of 10 -7 M dexamethasone. The highest producing subclone, No. 25, secreted approximately 16 μg/ml and 33 μg/ml in the absence and presence of dexamethasone, respectively. D. Transfection Of Sp2/O Cells With pING4143 And pING4150 Plasmid pING4143 contains DNA encoding rBPI(1-193)ala 132 fused to the A-MuLv promoter, optimized Kozak translation initiation sequence, and mouse kappa light chain 3' untranslated sequences along with the gpt gene for selection of MPA-resistant cells. The Sp2/O cells were transfected by electroporation with 40 μg of pING4143 DNA that was first digested with NotI, phenol-chloroform extracted, and ethanol precipitated. Following electroporation, the cells were allowed to recover for 48 hours in non-selective DMEM medium. The cells were then centrifuged and resuspended at a concentration of 5×10 4 cells/ml in DMEM medium supplemented with MPA (6 μg/ml) and xanthine (250 μg/ml) and plated at approximately 10 4 cells/well in 96-well plates. At approximately 2 weeks, colonies consisting of transfected cells were observed in the 96-well plates. Supernatants from wells containing single colonies were analyzed for the presence of BPI-reactive protein by ELISA. The highest producers were transferred to a 24-well plate. Productivity was assessed as extinct 24-well cultures for cells grown in the presence and absence of 10 -7 M dexamethasone. The best producer, Clone 134, secreted approximately 12 μg/ml and approximately 28 μg/ml in the absence and presence of dexamethasone, respectively. Clone 134 was transfected by electroporation with the vector, pING4150, which contains DNA encoding rBPI(1-193)ala 132 fused to the A-MuLv promoter and mouse light chain 3' untranslated region with the his gene for selection of transfectants. Prior to electroporation, the vector was first digested, and phenol-chloroform-extracted and ethanol precipitated. Following recovery for 48 hours in DMEM plus 10% FBS medium, the cells were plated in 96-well plates at approximately 10 4 cells/well in DMEM/FBS supplemented with 6 μg/ml MPA plus 250 μg/ml xanthine and 8 mM histidinol. Untransfected cells are unable to grow in the presence of MPA and histidinol. At approximately 2 weeks, colonies consisting of transfected cells were observed in the 96-well plates. Supernatants from wells containing single colonies were analyzed for the presence of BPI-reactive protein by ELISA. The highest producers were transferred to a 24-well plate. Productivity was assessed as extinct 24 well cultures for cells grown in the presence and absence of 10 -7 M dexamethasone. The highest producer, Clone 134-11, was re-designated C1770. Clone C1770 secreted 36 μg/ml without dexamethasone and greater than 42 μg/ml in the presence of dexamethasone. This clone (c1770) was deposited with the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 as Accession No. HB 11247. E. Transfection Of CHO-K1 Cells With pING4143 The CHO-K1 cell line was transfected with pING4143 DNA in the manner described in Section A for transfection of CHO-K1 cells with pING4533. At approximately 2 weeks, supernatants from approximately 800 wells containing single colonies were analyzed for the presence of BPI-reactive protein by ELISA. The top producers were transferred to 24-well plates. The top producers, secreting approximately 9-13 μg/ml, may next be adapted to serum-free medium in preparation for growth in fermenters. These may also be re-transfected with a vector, such as pING4150 or pING4154 with his or neo as selective markers, respectively, to provide a cell line which produces even higher levels of rBPI product. F. Transfection Of CHO-K1 Cells With pING4144 Plasmid pING4144 is similar to pING4143 except that it contains the human cytomegalovirus (hCMV) promoter instead of the A-MuLv promoter. The CHO-K1 cell line was transfected with pING4144 DNA in the manner described above in Section A. At approximately 2 weeks, supernatants from approximately 200 wells containing single colonies were analyzed for the presence of BPI-reactive protein by ELISA. The top producers were transferred to 24-well plates and rBPI expression determined in 24-well plates containing sodium butyrate. The top producer (clone 174) secreted approximately 3-5 μg/ml without butyrate and approximately 15-18 μg/ml in the presence of 5 mM butyrate in this assay. This clone, re-designated clone C1771, was deposited with the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852 as ATCC accession No. CRL 11246. Top producers may next be adapted to serum-free medium in preparation for growth in fermenters. These may also be re-transfected with a vector, such as pING4151 or pING4155, containing the rBPI gene under control of the hCMV promoter, but with his or neo as selective markers, respectively, to provide a cell line which produces even higher levels of BPI. G. Transfection Of NSO Cells With pING4143 NSO cells were transfected with pING4143 DNA by electroporation. At approximately 3 weeks, colonies consisting of transfected cells were observed in the 96-well plates. Supernatants from wells containing single colonies were analyzed for the presence of BPI-reactive protein by ELISA. The highest producers were transferred to a 24-well plate. Productivity was assessed as extinct 24-well cultures. The highest producers secreted a 15-16 μg/ml. The highest producers may be retransfected with a vector, such as pING4150, as described above to yield even higher producers. H. Transfection Of NSO Cells With pING4232 NSO cells were transfected by electroporation with pING4132, which contains DNA encoding rBPI(1-193)ala 132 fused to the optimal Kozak translation initiation sequence cloned into the vector pEE13 Bebbington, et al. Biotechnology, 10:169-175 (1992)!. Vector pEE13 contains the glutamine synthetase gene for selection of transfectants which are able to grow in medium lacking glutamine. At approximately three weeks, colonies consisting of transfected cells were observed in 96-well plates. Supernatants from wells containing single colonies were analyzed by ELISA. The highest producers were transferred to a 24-well plate. Productivity was assessed as extinct 24-well cultures. The highest producers, secreting 7-15 μg in extinct 24 well-cultures, may next be subjected to amplification in the presence of various concentrations of methionine sulfoximine. I. Transfection Of Sp2/O Cells with pING4145 Plasmid pING4145 contains DNA encoding rBPI(1-193)ala 132 fused to the A-MuLv promoter, optimized Kozak translation initiation sequence, mouse kappa light chain 3+ untranslated sequences, and a gpt gene for selection of MPA-resistant cells. The Sp2/O cells were transfected by electroporation with 40 μg of pING4145 DNA that was first digested with NotI, phenol-chloroform extracted, and ethanol precipitated. Following electroporation, the cells were allowed to recover for 48 hours in non-selective DMEM medium, centrifuged, and resuspended at a concentration of 5×10 4 cells/ml in DMEM medium supplemented with MPA (6 μg/ml) and xanthine (250 μg/ml). The cells may then be plated at approximately 10 4 cells/well in 96-well plates. At approximately 2 weeks, colonies consisting of transfected cells are observed in the 96-well plates. Supernatants from wells containing single colonies may then be analyzed for the presence of BPI-reactive protein by ELISA. The highest producers are transferred to a 24-well plate and productivity is assessed as extinct 24-well cultures for cells grown in the presence and absence of 10 -7 M dexamethasone. In order to maximize the expression of BPI, the highest producing Sp2/O transfectant may be transfected by electroporation with a vector which contains gene sequences encoding rBPI(1-193)ala 132 fused to the A-MuLv promoter and mouse light chain 3' untranslated region with the his gene for selection of transfectants. J. Transfection Of CHO-K1 Cells with pING4145. The CHO-K1 cell line was transfected with pING4145 DNA in the manner described above in Section A. At approximately 2 weeks, supernatants from approximately 500-800 wells containing single colonies may be analyzed for the presence of BPI-reactive protein by ELISA. The top producers are transferred to 24-well plates and BPI expression determined in 24-well plates containing S-sepharose. The top producers are next adapted to serum-free medium in preparation for growth in fermenters. These may also be re-transfected with a vector containing a different selective marker to provide a cell line which produces even higher levels of rBPI product. K. Expression Of rBPI Products from Insect Cells Another eukaryotic system in which rBPI products may be expressed is insect cells which have been infected with a recombinant baculovirus containing DNA encoding an rBPI product. Systems for generating recombinant virus and for achieving expression of recombinant products therefrom are commercially available (Invitrogen, San Diego, Calif.). DNA encoding rBPI(1-199), including the 31 amino acid signal sequence, was cloned into an NheI site in a pBlueBac transfer vector (Invitrogen). Sf9 insect cells (BRL; ATCC CRL 1711) were co-transfected with this vector and with wild type AcMNPV (Autographa californica multiple nuclear polyhidrosis virus, Invitrogen). Recombinant viral plaques were then identified, purified, and used to generate high-titer recombinant vital stocks as described in protocols available from BRL. The recombinant-produced baculovirus was used to infect further Sf9 cells. To do this, 8 separate 60 mm dishes of Sf9 cells were infected with the baculovirus. Each of the 8 dishes was sampled at different times during the day by collecting medium from a dish of infected cells. Upon collection, the medium was centrifuged at 1000 rpm for 10 minutes and the supernatant was stored at 4° C. Cells were then rinsed once with 4 ml PBS and lysed with 100 μl/dish NP40 lysis buffer (1% NP40, 150 mM NaCl, 50 mM Tris-HCl, pH 8.0) by incubating on ice for 30 minutes. Cells were then collected into an Eppendorf tube with a cell scraper. Cell lysates were then spun in a microfuge for 2 minutes. The lysate supernatant was transferred to a new tube and stored at -20° C. Media samples from each daily time point were analyzed for BPI content by ELISA and lysates were analyzed by Western using an anti-BPI antibody. No rBPI product was detectable in the media by ELISA on days 1-4 post-infection. However, on days 5-6 post-infection, a peak of 200-500 ng/ml rBPI product was detected in media samples. Western analysis of the lysates showed a BPI-reactive band of approximately 23 Kd at day 2 post-infection. That band showed increasing intensity through day 6. Table II, below, summarizes the transfections detailed in Sections A-J above. TABLE II______________________________________Host Cell Transfected With______________________________________CHO-DG44 pING4222CHO-Kl pING4533, pING4143 pING4144, pING4145NSO pING4143, pING4232SP2/O pING4223 followed by pING4221, pING4143 followed by plNG4150, pING4145______________________________________ EXAMPLE 3 Construction Of Plasmids For in vitro Transcription And Translation Of rBPI(1-199)ala 132 And rBPI(1-199)Ser 135 In vitro transcription/translation studies were conducted using plasmid pIC127 as a source of DNA encoding rBPI (1-199). Construction of pIC127 was carried out as follows. DNA encoding rBPI(1-199), including the 31-amino acid signal sequence, was PCR amplified from a plasmid containing full-length cDNA encoding BPI in pGEM-72f(+). The amplification was done such that a SalI site was incorporated at the 5' end and XhoI and SstII sites were incorporated at the 3' end of the rBPI-encoding sequence by using the primers BPI-3: GTCGACGCATGCGAGAGAACATGGC (SEQ ID NO: 12) and BPI-2: CCGCGGCTCGAGCTATATTTTGGTCAT (SEQ ID NO: 9). The resulting PCR amplified fragment was blunt-end cloned into the SmaI site of the multiple cloning region of plasmid pT7T3 18μ (Pharmacia LKB Technology, Piscataway N.J.) in order to generate pIC102. . The pIC102 insert encoding rBPI(1-199)and the 31-amino acid signal were then excised by digestion of the plasmid with BamHI and Asp718I. A BamHI site flanks the SalI site in pIC102 and an Asp718I site flanks the SstII site in pIC102. The ends of the excised fragment were made blunt with T4 DNA polymerase and the blunt fragment was then cloned into plasmid pGEM1. (ProMega, Madison, Wis.) which had first been digested with PstI and EcoRI and blunted with T4 DNA polymerase. The resulting construction was designated pIC124 and has the rBPI (1-199)-encoding insert oriented such that its 5' end is adjacent to the Sp6 promoter in pGEM1. The 31-amino acid signal sequence in the pIC124 insert was then excised by removing the region between two HincII sites in pIC124 to create pIC127. The excised region was replaced with a linker which restored the initiation codon (ATG) and the sequence encoding the first amino acid of BPI. Two fragments were isolated from pIC124 digestion with HincII and SstII: (1) the HincII-SstII fragment containing the rBPI(1-199) coding region excluding the codon for the first amino acid; and (2) the SstII-HincII fragment comprising the remainder of the plasmid. The first codon in the BPI coding sequence and a codon for methionine in front of the BPI sequence were inserted through use of linker formed from two complementary annealed oligonucleotides, BPI-28: GACGCCACCATGGTC (SEQ ID NO: 13) and BPI-29: GACCATGGTGGCGTC (SEQ ID NO: 14). Those two oligonucleotides were ligated together with the HincII-SstII and SstII-HincII fragments from pIC124 to form pIC127. Two plasmids, pML101 and pML102, were constructed using pIC127 for in vitro transcription/translation of rBPI(1-199)ala 132 and rBPI(1-199)ser 135 . To do this, pIC127 was digested with SstII and EcoRI and the large SstII-EcoRI fragment was purified. To construct pmL101, which contains an rBPI(1-199)ala 132 insert, the EcoRI-SstII fragment from pING4519 was ligated to the SstII-EcoRI fragment from PIC127. To construct pML102, which contains the rBPI(1-199)Ser 135 insert, the EcoRI-sstII fragment from pING4520 was ligated to the sstII-EcoRI fragment from pIC127. rBPI(1-199), rBPI(1-199)ser 135 , and BPI(1-199)ala 132 were expressed in vitro from plasmids pIC127, pML101, and pML102 using the TNT SP6 coupled Reticulocyte Lysate System from ProMega (Madison, Wis.). That system allows in vitro coupled transcription and translation of cloned genes using a eukaryotic translation system. Each coupled transcription/translation was carried out using the manufacturer's protocols with 2 μg of plasmid DNA in a total volume of 25 μl, including 35 S-methionine to generate labeled protein. The labeled protein products were added in 5 μl aliquots to a 20 μl urea sample buffer and heated at 95° C. for 3 minutes. Aliquots (10 μl) of each sample were run on a 15% SDS-Polyacrylamide gel either with or without DTT (50 mM). After fixing and drying the gel, the labeled protein bands were visualized by autoradiography. Results of the autoradiography demonstrate that cDNA encoding rBPI(1-199), rBPI(1-199)ala 132 , and rBPI(1-199)cys 135 expressed protein products of the expected size of approximately 23 Kd for a BPI N-terminal fragment. Moreover, all three expression products, rBPI(1-199), rBPI(1-199)ala 132 , and rBPI(1-199)cys 135 , were capable of generating higher molecular weight species of the size expected for BPI(1-199) dimers, as well as larger species, all of which disappeared upon reduction with DTT. It is thought that the expression of dimeric species in the rBPI(1-199)cys 135 and rBPI(1-199)ala 132 products may be the result of using a cell-free in vitro transcription/translation system. Such a system does not allow proper post-translational processing, folding, etc. which would normally occur in cellular translation. Thus, it may be that proper disulfide linkages do not always form in the in vitro system, leading to formation of dimer in some cases. Labeled proteins generated in the above-described in vitro expression system were next tested for LPS binding activity. Wells of microtiter plates were coated with LPS from Salmonella minnesota R7 (Rd mutant) (5 mg/ml in methanol stock culture) in 0.1 M Na 2 CO 3 /20 mM EDTA (ethylenediamine tetraacetic acid) at pH 9.4 (a total of 2 μg LPS in a 50 μl well). Following overnight incubation at 4° C., the wells were rinsed with water and dried at 37° C. The wells were then blocked with 215 μl Dulbecco's-PBS/0.1% BSA for 3 hours at 37° C. The blocking solution was then discarded and the wells were washed with PBS/0.2% Tween-20. The rBPI samples were then added (2 μl of the translation reactant) to a 50 μl total volume in PBS/0.2% Tween. Following overnight incubation at 4° C., the wells were washed 3 times with PBS/0.2% Tween and the amount of labeled protein remaining in each well was determined by liquid scintillation counting. The results demonstrated that approximately equivalent LPS binding took place for all three BPI species referred to above. rBPI(1-199) displayed binding of 48,690 cpm; rBPI(1-199)ala 132 displayed binding of 59,911 cpm; and rBPI(1-199)cys 135 displayed binding of 52,537 cpm. each of the aforementioned values represents the average of triplicate determinations. The average binding of the control (no DNA) was 5,395 cpm. EXAMPLE 4 Product Characterization A. Physical Characterization Characterization of rBPI products was accomplished using reverse phase (C4) HPLC, cation exchange (MA7C) HPLC, SDS-PAGE, and electrospray ionization mass spectrometry (ESI-MS). The rBPI products to be characterized were purified from roller bottles or from a 10 Liter fermenter harvest by either a single-step purification procedure or by a multi-step procedure. The single-step procedure was essentially that disclosed in co-pending, co-owned U.S. patent application Ser. No. 07/885,501 by Grinna, incorporated herein by reference, with the addition of a second wash step. In brief, S-sepharose beads were added to a growth medium containing rBPI products. The S-sepharose was then removed from the medium and washed with 20 mM sodium acetate and 100 mM sodium chloride at pH 4.0. A second wash was performed with 20 mM sodium acetate and 700 mM sodium chloride at pH 4.0. The purified rBPI products were eluted with 20 mM sodium acetate and 1000 mM sodium chloride at pH 4.0. The multi-step purification procedure involved the purification of pooled batches of rBPI products which had first been purified separately as described above. After purification of each of twenty individual rBPI product batches by the single-step method, the batches were pooled and repurified by first diluting the salt concentration of the pooled batches to 200 mM. The pooled sample was then loaded onto an S-sepharose column and was washed at pH 4.0 with 20 mM sodium acetate, and 200 mM sodium chloride followed by 700 mM sodium chloride. The rBPI products were eluted using 20 mM sodium acetate and 1000 mM sodium chloride at pH 4.0. The purified rBPI products were then analyzed to determine their physical characteristics. 1. SDS-PAGE Analysis of rBPI Products SDS-PAGE analysis of rBPI products was carried out using 14% polyacrylamide gels and a tris-glycine buffer system under reducing and non-reducing conditions. Protein bands were stained with either Coomassie Blue or silver stain for visualization. As shown in FIG. 1, non-reduced rBPI(1-199) appeared as a major band at approximately 23 kD and a minor band at approximately 40 kD. The major band was identified as rBPI(1-199) by comparison with simultaneously-run standards and the minor band was identified as a dimeric form of rBPI(1-199) by immunostaining. Upon addition of a 1/20 volume of 0.4 M dithiothreitol (DDT) to a separate sample of rBPI(1-199), SDS-PAGE revealed a single, well-defined band corresponding to the 23 kD monomeric species of rBPI(1-199) identified under non-reducing conditions as described above. SDS-PAGE analysis of the rBPI(1-199)ala 132 product revealed a single band which migrated with the single 23 kD rBPI(1-199) band under reducing conditions. Under non-reduced conditions, rBPI(1-199)ala 132 migrated with thte faster-migrating of the two closely-spaced bands seen for rBPI(1-199) (corresponding to the 23 kD band). These results, shown in FIGS. 2A and 2B, indicate that rBPI(1-199)ala 132 exists in essentially monomeric form after purification. Thus, rBPI products in which a cysteine residue is replaced by alanine display significant resistance to dimer formation. 2. Cation Exchange HPLC Analysis of rBPI Products Cation exchange HPLC using an MA7C column was also employed to measure the dimer content of rBPI products. A Bio-Rad MA7C cartridge (4.6×30 mm, Bio-Rad Catalog No. 125-00556) equilibrated with 40% buffer B (20 mM MES, 1M NaCl, pH 5.5) at 1.0 ml/min was used. The rBPI(1-199) product was analyzed by diluting a 1 ml sample to 100 μg/ml and 200 μl of the diluted sample was injected onto the column. The rBPI was eluted with a gradient of 40% to 100% buffer B over 6 minutes. Buffer A comprised 20 mM MES at pH 5.5. Absorbance was monitored at 229 nm. Analysis of rBPI(1-199) revealed two peaks. A first peak eluted with a retention time of approximately 3 minutes as shown in FIG. 3. A second, smaller peak eluted at approximately 6 minutes. The first peak, shown in FIG. 3, represents rBPI(1-199) monomer and the second peak in FIG. 3 represents rBPI(1-199) dimer as determined by .comparisons with the retention times of purified monomer and dimer standards. The second (dimer) peak did not appear when samples were reduced with DTT prior to being injected on the column. Identical procedures were used to determine the elution pattern of rBPI(1-199)ala 132 . As shown in FIG. 4, rBPI(1-199)ala 132 elutes as a single peak with a retention time corresponding to that observed for the rBPI(1-199) monomer peak. There was no evidence of dimer in the rBPI(1-199)ala 132 sample. 3. Reverse Phase (C4) HPLC and Electrospray-ionization Mass Spectrometry Analysis of rBPI Products Microheterogeneity of rBPI products was revealed by reverse phase HPLC and electrospray-ionization mass spectrometry (ESI-MS). For the HPLC analysis, a Brownlee BU-300 C4 column was equilibrated with 37% Mobile Phase B (80% acetonitrile/0.065% TFA) at a flow rate of 0.5 ml/min. Samples (1 ml each) of rBPI(1-199) were diluted to 100 μg/ml and 50 μl of the sample was injected. The column was washed with 37% Mobile Phase B for 2.5 minutes and then eluted using a gradient from 37% to 50% Mobile Phase B over 20 minutes. Mobile Phase A was 5% acetonitrile/0.1% TFA and absorbance was monitored at 220 nm. The results of reverse phase HPLC analysis of rBPI(1-199) products are shown in FIG. 5. rBPI(1-199) products elute as a second (major) peak with a partially-resolved first (minor) peak on the leading edge of the second peak. Upon reduction with DTT only one peak, corresponding to the second peak, elutes from the column. Identical procedures were used to analyze rBPI(1-199)ala 132 products. As shown in FIG. 6, rBPI(1-199)ala 132 eluted as a single peak corresponding to the second (major) peak referred to above. The eluates corresponding to the first and second HPLC peaks described above from three separate batches of rBPI(1-199) were isolated and analyzed to determine their content by ESI-MS. Analysis of the eluate which produced the second (major) peak from the rBPI(1-199) run revealed a slightly lower mass than would be expected for a 199-amino acid protein. These data indicate that the most abundant mass found in the second peak eluate corresponded to a 1-193 rBPI protein fragment. However, other species, ranging in size from 1-198 to 1-194, are also present. Analysis of the eluate producing the single peak obtained from HPLC on rBPI(1-199)ala 132 revealed results similar to those obtained from the eluate which produced the second (major) peak above. These results are consistent with peptide mapping data which reveal truncated carboxy termini in rBPI(1-199) products. When the same analysis was performed on rBPI(1-193) products, significantly reduced C-terminal heterogeneity was observed. The ESI-MS data obtained from rBPI(1-193) products revealed that approximately 85% of the protein contains either the first 191, 193, or 193 (+an N-terminal alanine) amino acids of the BPI N-terminal. The results are shown in Table III. TABLE III______________________________________Electrospray-Ionization Mass Spectrometry Resultsfor rBPI(1-193) and rBPI(1-199) HPLC Monomer Peaks ApproximateExpected Approximate Predicted Amino RelativerBPI Product Molecular Mass Acid Residues Intensity*______________________________________rBPI(1-199) 21407 1-193 50.9% 21606 1-195 28.9% 21505 1-194 20.1% 21738 1-196 <10% 21846 1-197 <10% 21966 1-198 <10%rBPI(1-193) 21408 1-193 36.2% 21193 1-191 34.1% 21293 1-192 <10% 21477 1-193 + N- 14.5% terminal alanine 20924 1-189 15.2%______________________________________ *Only species detected as being present in amounts greater than 10% were quantitated. These species were then normalized to 100%. These data demonstrate that, while the rBPI(1-199)-encoding DNA produced no full-length (i.e. amino acids 1-199 of the BPI N-terminal) protein, the rBPI (1-193)-encoding DNA produced significant amounts of the rBPI(1-193) protein. Based upon these and other data, it appears that significant reductions in heterogeneity and significant increases in production of the intended protein (i.e. that for which the DNA insert codes may be obtained), while maintaining optimal bactericidal and LPS-binding activity, by using truncated forms of the rBPI-encoding DNA. It is expected that truncation of the DNA to be expressed will produce significant reductions in heterogeneity of the expression product to the extent that the DNA to be expressed is not truncated beyond the cysteine at amino acid residue 175. Expression products of truncated forms of DNA encoding rBPI proteins which have in the range of the first 176 amino acids of the BPI N-terminal to the first 193 amino acids of the BPI N-terminal are also expected to retain full bactericidal and LPS-binding activity. The ESI-MS data also revealed the presence of microheterogeneity at the amino terminal of rBPI products. Forms of the rBPI product having an alanine residue at the amino terminus were found and confirmed by sequencing of tryptic peptides. As shown in FIG. 5, the ESI-MS study of the eluate which produced the first (minor) reverse phase HPLC peak revealed proteins having a mass distribution similar to those which formed the second (major) peak except that each mass value was higher by approximately 119-120 Daltons. These data suggest that the eluate producing the first (minor) HPLC peak described above contains a disulfide-linked cysteine adduct, as this would account for the uniform shift of the mass values. To test the hypothesis that the first (minor) reverse phase HPLC peak produced by rBPI(1-199) represents cysteine adducts, rBPI(1-199) was exposed to Ellman's reagent (dithionitrobenzenoic acid, DTNB) which binds to free sulfhydryl groups in roughly molar equivalents. Such treatment demonstrated that there is less than one mole of free sulfhydryl per mole of rBPI(1-199). Given the presence of three cysteine residues in BPI (at positions 132, 135 and 175), these results support the notion that there is either an intramolecular disulfide link in the rBPI products or that two of the sulfhydryl groups are sterically unavailable. rBPI(1-199)ala 132 showed no reactivity with Ellman's reagent. 4. Storage Stability of rBPI(1-199) Products Samples of rBPI(1-199) (1 mg/ml) in a buffer comprising 20 mM sodium citrate, 0.15 M Sodium Chloride buffer, 0.1% poloxamer, and 0.002% polysorbate 80 at pH 5.0 were analyzed to determine their storage stability over an 8-week period at the recommended storage temperature of 2°-8° C. and at higher temperatures of 22° C. and 37° C. The results for storage at 2°-8° C., presented in Table IV, show an increase in the presence of dimer (from 1% to 4%), but no significant increase in cysteine adduct or particle formation in the sample. TABLE IV__________________________________________________________________________ % % % LALStorage Appearance/ Unknown Dimer Protein Cysteine Inhibition Particles/mL Particles/mLTime Color pH Impurities by HPLC mg/mL Adduct IC.sup.50, nG/mL ≧10 μm ≧25 μm__________________________________________________________________________initial clear/colorless 5.1 ND 1.0 1.04 12 10 230 54 weeks clear/colorless 5.0 ND 3.2 1.02 11 11 113 28 weeks clear/colorless 5.0 ND 4.4 1.02 14 9 125 5__________________________________________________________________________ However, storage at the increased temperatures of 22° C. and 37° C. show that the presence of dimer and particles in the sample increased dramatically and the amount of cysteine adduct increased moderately. These results are shown in Table V. Additionally, when rBPI(1-193)ala 132 is stored at 22° C. to 37° C., no dimer was detected after storage for two weeks. Under similar conditions, rBPI(1-199) displays significant increases. TABLE V__________________________________________________________________________ % % Dimer % LAL Particles/ Storage Appearance/ Unknown by Protein Cysteine Inhibition Particles/mL mLTemperature Time Color pH Impurities HPLC mg/mL Adduct IC.sup.50 , nG/mL ≧10 μm ≧25__________________________________________________________________________ μm initial clear/colorless 5.1 ND 1.0 1.04 12 10 230 522° C. 4 clear/colorless 5.0 ND 4.5 1.02 12 10 100 4 weeks 8 clear/colorless 5.0 ND 6.8 1.02 14 6 126 3 weeks37° C. 4 a few particles 5.0 ND 7.9 0.96 16 12 1,709 20 weeks 8 numerous 5.0 ND 13.1 0.88 18 7 20,287 611 weeks particles__________________________________________________________________________ 5. Turbidity Of rBPI Product Pharmaceutical Compositions Experiments were done to determine the turbidity of various rBPI-containing pharmaceutical compositions. In this context, turbidity refers to the tendency of pharmaceutical compositions to engage in unfolding (i.e., loss of tertiary protein structure) and/or particle formation (interactions between individual proteins to form large (>10 μm) particles). The pharmaceutical compositions tested contained either rBPI(1-199), rBPI(1-199)ala 132 , or rBPI(1-193)ala 132 in either a citrate buffer (20 mM sodium citrate/150 mM sodium chloride, pH 5.0) or a citrate buffer containing 0.1% poloxamer 188 (a poloxamer surfactant comprised of polyoxypropylene-polyoxyethylene block copolymer) and 0.002% polysorbate 80 (a polysorbate surfactant comprising polyoxyethylene sorbitan fatty acid ester). As mentioned above, use of a combination poloxamer/polysorbate surfactant system stabilizes pharmaceutical compositions as taught in co-owned, co-pending U.S. patent application Ser. No. 08/190,869, now U.S. Pat. No. 5,488,034, by McGregor et al., incorporated herein by reference. Samples were analyzed to determine their resistance to turbidity over time at increasing temperature and at either pH 7.0 or pH 5.0. Prior to analysis, all samples were diluted to a concentration of 0.1 mg/ml in either 50 mM potassium phosphate or 20 mM citrate buffer at pH 7.0. Turbidity measurements were obtained by placing samples in quartz cuvettes for use in a Shimadzu UV-160 UV-Vis spectrophotometer (Shimadzu, Pleasanton, Calif.) equipped with a temperature-controlled cuvette holder attached to a recirculating water bath. Upon equilibrating the cuvette holder at the desired temperature (57° C., 65° C., or 85° C., see below), absorbance at 280 nm was measured to confirm that samples had been diluted to the proper concentration. Following this, the absorbance of samples at 350 nm was measured every 2 minutes for 1 hour to determine the change in absorbance over time. Results are presented in FIG. 7; wherein "formulated" refers to the rBPI product in citrate buffer containing the poloxamer/polysorbate combination referred to above, and "unformulated" refers to rBPI compounds in citrate buffer alone. A lower rate of change in turbidity (i.e., a lower rate of increase in absorbance over time) indicates increased stability against unfolding and the formation of particles. As shown in FIG. 7, the addition of the aforementioned combination of surfactants resulted in increased stability (resistance to particle formation and unfolding) of all compositions tested. Moreover, the rBPI(1-199)ala 132 and rBPI(1-193)ala 132 exhibited greatly improved resistance to unfolding and particle formation relative to wild-type compositions-regardless of whether the surfactant combination was present. Similar results were obtained at pH 5.0 and 65° C., at pH 5.0 and 75° C. and at 85° C., respectively. Overall, compositions with the surfactant combination and/or the cysteine deletion showed greatly increased stability over time and through increases in temperature as compared to compositions with no surfactant and/or having the wild type BPI(1-199) N-terminal construction. B. In Vitro Activity Characterizations In Vitro activity of rBPI(1-199)ala 132 products was determined by binding of the products to LPS, by the LAL inhibition assay, and by the bactericidal potency of the products. 1. Binding Of rBPI(1-199)ala 132 To LPS Samples (20 μg to 60 μg each) of E. coli (Strain 0111-B4) or S. minnesota (Rd mutant) lipopolysaccharide (Sigma Chemical, St. Louis, Mo.) were used to determine the ability rBPI(1-199)ala 132 products to bind LPS. The LPS samples were size fractionated by SDS-PAGE and silver stained for visualization or electrotransferred to a nitrocellulose membrane (BA25, Schleicher and Schuell, Keene, N.M.) with appropriate pre-stain standards. The LPS blots were processed by soaking the membrane in 50 mM Tris, 0.2 M NaCl (TBS), and 30 mg/ml bovine serum albumin (BSA) at pH 7.4 for 30 minutes at 37° C. Membranes were then incubated in a solution containing 2-4 μg of purified or partially purified rBPI(1-199)ala 132 or a control protein (either rBPI(1-199) or rBPI holoprotein) for 12-18 hours at 21° C. to 42° C. After incubation, the membranes were then washed with TBS-BSA. The solution was changed at least three times over a 30 minute period. The washed membranes were then incubated for 3 hours in a 1:1000 dilution of rabbit anti-rBPI(1-199) in TBS containing 1 mg/ml BSA. Membranes were next washed at least three times and were developed using the Chemiluminescent Detection System (Tropix Systems, Bedford, Mass.) according to the manufacturers instructions, using 5× PBS and 0.25% gelatin (Bio-Rad) in place of I-block. The results, demonstrate that rBPI(1-199)ala 132 binds to LPS fixed to nitrocellulose as well or better than rBPI(1-199). 2. E. coli Growth Inhibition Assay The E. coli broth growth inhibition assay was conducted to determine the bactericidal potency of rBPI products by treating E. coli with rBPI(1-199) or rBPI(1-199)ala 132 analogs and monitoring the inhibition of broth growth as a measure of bactericidal activity. A "rough" strain of E. coli with short-chain LPS, designated J5 (a rough UDP-4-epimerase-less mutant of E. coli strain 0111:B4), was used in the assay. Cells were grown in a triethanolamine-buffered mineral salts medium (Simon, et al. Proc. Nat. Acad Sci, 51:877 (1964)) which rendered E. coli especially sensitive to BPI. The cells were washed and resuspended in 0.9% NaCl to a density of about 5×10 8 cells/ml. Approximately 5×10 6 to 1×10 7 E. coli cells were incubated for 30-60 minutes with either rBPI(1-199) or with rBPI(1-199)ala 132 analogs at a concentration of 5 μg/ml with a buffered solution (10% Hanks Balanced Salts, 40 mM Tris-Hcl, pH 7.5. 0.1% casamino acids) in a volume of 200-400 ml. In addition, the assay was run separately with either rBPI(1-199) or rBPI(1-199)ala 132 analog and 100 mM MgCl 2 . Following incubation, the cells were diluted with 10 volumes of nutrient broth supplemented with 0.9% Nacl. Broth growth was then monitored for several hours. The results, demonstrate that rBPI(1-199)ala 132 analogs possess bactericidal activity as potent or more potent than rBPI(1-199). The bactericidal activity of both rBPI(1-199)ala 132 analogs and that of rBPI(1-199) were reduced, as expected, by MgCl 2 . 3. LAL Inhibition Assay The LAL inhibition assay was used to determine the ability of rBPI(1-193)ala 132 to bind LPS. An LAL inhibition assay is described in Gazzano-Santoro, Infect. Immun., 60:4754-4761 (1992). Results of the LAL assay demonstrate that rBPI(1-193)ala 132 has an IC-50 value of 10, which is equal to that for rBPI(1-199). These data indicate that the analog competes as well as the wild-type rBPI product for binding to LPS. C. Efficacy Of rBPI(1-199)ala 132 In An Animal Model Of Lethal Endotoxemia An animal model of endotoxemia was used to evaluate the comparative effectiveness of rBPI(1-199)ala 132 and rBPI(1-199) against endotoxic shock. Male ICR mice received intravenous injections of 800 μg/kg actinomycin-D and either 0.5 μg/kg or 1.0 μg/kg of an endotoxin (E. coli, Strain 0111:B4). Immediately following the injection of endotoxin, the mice received an intravenous injection (0.5 mg/kg or 5.0 mg/kg) of either rBPI(1-199) or rBPI(1-199)ala 132 . Buffered vehicle was used as a control. Deaths were then recorded over a 7-day period. The results are presented below in Table VI. TABLE VI______________________________________ BPI Dose # Dead/Total % Mortality______________________________________Buffer only 0 14/15 93rBPI.sub.23 0.5 mg/kg 7/15 47 5.0 mg/kg 8/15 53rBPI.sub.23 -cys 0.5 mg/kg 14/15 93 5.0 mg/kg 8/16 50______________________________________ As seen in Table VI, both rBPI(1-199)ala 132 and rBPI(1-199) provided significant protection against the lethal effects of the endotoxin. Although the present invention has been presented in terms of its preferred embodiments, the skilled artisan realizes that numerous modifications and substitutions are within the scope of the present teaching. For example, substitution of the cysteine at position 132 or 135 of the BPI N-terminal fragment with non-polar amino acids other than alanine or serine is contemplated by the invention. Thus, the scope of the appended claims and any future amendments thereto. __________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 14(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 1813 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(ix) FEATURE:(A) NAME/KEY: CDS(B) LOCATION: 31..1491(ix) FEATURE:(A) NAME/KEY: mat_peptide(B) LOCATION: 124..1491(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:CAGGCCTTGAGGTTTTGGCAGCTCTGGAGGATGAGAGAGAACATGGCCAGGGGC54MetArgGluAsnMetAlaArgGly31-30-25CCTTGCAACGCGCCGAGATGGGTGTCCCTGATGGTGCTCGTCGCCATA102ProCysAsnAlaProArgTrpValSerLeuMetValLeuValAlaIle20-15- 10GGCACCGCCGTGACAGCGGCCGTCAACCCTGGCGTCGTGGTCAGGATC150GlyThrAlaValThrAlaAlaValAsnProGlyValValValArgIle515TCCCAGAAGGGCCTGGACTACGCCAGCCAGCAGGGGACGGCCGCTCTG198SerGlnLysGlyLeuAspTyrAlaSerGlnGlnGlyThrAlaAlaLeu10152025CAGAAGGAGCTGAAGAGGATCAAGATTCCTGACTACTCAGACAGCTTT246GlnLysGluLeuLysArgIleLysIleProAspTyrSerAspSerPhe303540AAGATCAAGCATCTTGGGAAGGGGCATTATAGCTTCTACAGCATGGAC294LysIleLysHisLeuGlyLysGlyHisTyrSerPheTyrSerMetAsp455055ATCCGTGAATTCCAGCTTCCCAGTTCCCAGATAAGCATGGTGCCCAAT342IleArgGluPheGlnLeuProSerSerGlnIleSerMetValProAsn606570GTGGGCCTTAAGTTCTCCATCAGCAACGCCAATATCAAGATCAGCGGG390ValGlyLeuLysPheSerIleSerAsnAlaAsnIleLysIleSerGly758085AAATGGAAGGCACAAAAGAGATTCTTAAAAATGAGCGGCAATTTTGAC438LysTrpLysAlaGlnLysArgPheLeuLysMetSerGlyAsnPheAsp9095100105CTGAGCATAGAAGGCATGTCCATTTCGGCTGATCTGAAGCTGGGCAGT486LeuSerIleGluGlyMetSerIleSerAlaAspLeuLysLeuGlySer110115120AACCCCACGTCAGGCAAGCCCACCATCACCTGCTCCAGCTGCAGCAGC534AsnProThrSerGlyLysProThrIleThrCysSerSerCysSerSer125130135CACATCAACAGTGTCCACGTGCACATCTCAAAGAGCAAAGTCGGGTGG582HisIleAsnSerValHisValHisIleSerLysSerLysValGlyTrp140145150CTGATCCAACTCTTCCACAAAAAAATTGAGTCTGCGCTTCGAAACAAG630LeuIleGlnLeuPheHisLysLysIleGluSerAlaLeuArgAsnLys155160165ATGAACAGCCAGGTCTGCGAGAAAGTGACCAATTCTGTATCCTCCAAG678MetAsnSerGlnValCysGluLysValThrAsnSerValSerSerLys170175180185CTGCAACCTTATTTCCAGACTCTGCCAGTAATGACCAAAATAGATTCT726LeuGlnProTyrPheGlnThrLeuProValMetThrLysIleAspSer190195200GTGGCTGGAATCAACTATGGTCTGGTGGCACCTCCAGCAACCACGGCT774ValAlaGlyIleAsnTyrGlyLeuValAlaProProAlaThrThrAla205210215GAGACCCTGGATGTACAGATGAAGGGGGAGTTTTACAGTGAGAACCAC822GluThrLeuAspValGlnMetLysGlyGluPheTyrSerGluAsnHis220225230CACAATCCACCTCCCTTTGCTCCACCAGTGATGGAGTTTCCCGCTGCC870HisAsnProProProPheAlaProProValMetGluPheProAlaAla235240245CATGACCGCATGGTATACCTGGGCCTCTCAGACTACTTCTTCAACACA918HisAspArgMetValTyrLeuGlyLeuSerAspTyrPhePheAsnThr250255260265GCCGGGCTTGTATACCAAGAGGCTGGGGTCTTGAAGATGACCCTTAGA966AlaGlyLeuValTyrGlnGluAlaGlyValLeuLysMetThrLeuArg270275280GATGACATGATTCCAAAGGAGTCCAAATTTCGACTGACAACCAAGTTC1014AspAspMetIleProLysGluSerLysPheArgLeuThrThrLysPhe285290295TTTGGAACCTTCCTACCTGAGGTGGCCAAGAAGTTTCCCAACATGAAG1062PheGlyThrPheLeuProGluValAlaLysLysPheProAsnMetLys300305310ATACAGATCCATGTCTCAGCCTCCACCCCGCCACACCTGTCTGTGCAG1110IleGlnIleHisValSerAlaSerThrProProHisLeuSerValGln315320325CCCACCGGCCTTACCTTCTACCCTGCCGTGGATGTCCAGGCCTTTGCC1158ProThrGlyLeuThrPheTyrProAlaValAspValGlnAlaPheAla330335340345GTCCTCCCCAACTCCTCCCTGGCTTCCCTCTTCCTGATTGGCATGCAC1206ValLeuProAsnSerSerLeuAlaSerLeuPheLeuIleGlyMetHis350355360ACAACTGGTTCCATGGAGGTCAGCGCCGAGTCCAACAGGCTTGTTGGA1254ThrThrGlySerMetGluValSerAlaGluSerAsnArgLeuValGly365370375GAGCTCAAGCTGGATAGGCTGCTCCTGGAACTGAAGCACTCAAATATT1302GluLeuLysLeuAspArgLeuLeuLeuGluLeuLysHisSerAsnIle380385390GGCCCCTTCCCGGTTGAATTGCTGCAGGATATCATGAACTACATTGTA1350GlyProPheProValGluLeuLeuGlnAspIleMetAsnTyrIleVal395400405CCCATTCTTGTGCTGCCCAGGGTTAACGAGAAACTACAGAAAGGCTTC1398ProIleLeuValLeuProArgValAsnGluLysLeuGlnLysGlyPhe410415420425CCTCTCCCGACGCCGGCCAGAGTCCAGCTCTACAACGTAGTGCTTCAG1446ProLeuProThrProAlaArgValGlnLeuTyrAsnValValLeuGln430435440CCTCACCAGAACTTCCTGCTGTTCGGTGCAGACGTTGTCTATAAA1491ProHisGlnAsnPheLeuLeuPheGlyAlaAspValValTyrLys445450455TGAAGGCACCAGGGGTGCCGGGGGCTGTCAGCCGCACCTGTTCCTGATGGGCTGTGGGGC1551ACCGGCTGCCTTTCCCCAGGGAATCCTCTCCAGATCTTAACCAAGAGCCCCTTGCAAACT1611TCTTCGACTCAGATTCAGAAATGATCTAAACACGAGGAAACATTATTCATTGGAAAAGTG1671CATGGTGTGTATTTTAGGGATTATGAGCTTCTTTCAAGGGCTAAGGCTGCAGAGATATTT1731CCTCCAGGAATCGTGTTTCAATTGTAACCAAGAAATTTCCATTTGTGCTTCATGAAAAAA1791AACTTCTGGTTTTTTTCATGTG1813(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 487 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:MetArgGluAsnMetAlaArgGlyProCysAsnAlaProArgTrpVal31-30-25-20SerLeuMetValLeuValAlaIleGlyThrAlaValThrAlaAlaVal15-10-51AsnProGlyValValValArgIleSerGlnLysGlyLeuAspTyrAla51015SerGlnGlnGlyThrAlaAlaLeuGlnLysGluLeuLysArgIleLys202530IleProAspTyrSerAspSerPheLysIleLysHisLeuGlyLysGly354045HisTyrSerPheTyrSerMetAspIleArgGluPheGlnLeuProSer50556065SerGlnIleSerMetValProAsnValGlyLeuLysPheSerIleSer707580AsnAlaAsnIleLysIleSerGlyLysTrpLysAlaGlnLysArgPhe859095LeuLysMetSerGlyAsnPheAspLeuSerIleGluGlyMetSerIle100105110SerAlaAspLeuLysLeuGlySerAsnProThrSerGlyLysProThr115120125IleThrCysSerSerCysSerSerHisIleAsnSerValHisValHis130135140145IleSerLysSerLysValGlyTrpLeuIleGlnLeuPheHisLysLys150155160IleGluSerAlaLeuArgAsnLysMetAsnSerGlnValCysGluLys165170175ValThrAsnSerValSerSerLysLeuGlnProTyrPheGlnThrLeu180185190ProValMetThrLysIleAspSerValAlaGlyIleAsnTyrGlyLeu195200205ValAlaProProAlaThrThrAlaGluThrLeuAspValGlnMetLys210215220225GlyGluPheTyrSerGluAsnHisHisAsnProProProPheAlaPro230235240ProValMetGluPheProAlaAlaHisAspArgMetValTyrLeuGly245250255LeuSerAspTyrPhePheAsnThrAlaGlyLeuValTyrGlnGluAla260265270GlyValLeuLysMetThrLeuArgAspAspMetIleProLysGluSer275280285LysPheArgLeuThrThrLysPhePheGlyThrPheLeuProGluVal290295300305AlaLysLysPheProAsnMetLysIleGlnIleHisValSerAlaSer310315320ThrProProHisLeuSerValGlnProThrGlyLeuThrPheTyrPro325330335AlaValAspValGlnAlaPheAlaValLeuProAsnSerSerLeuAla340345350SerLeuPheLeuIleGlyMetHisThrThrGlySerMetGluValSer355360365AlaGluSerAsnArgLeuValGlyGluLeuLysLeuAspArgLeuLeu370375380385LeuGluLeuLysHisSerAsnIleGlyProPheProValGluLeuLeu390395400GlnAspIleMetAsnTyrIleValProIleLeuValLeuProArgVal405410415AsnGluLysLeuGlnLysGlyPheProLeuProThrProAlaArgVal420425430GlnLeuTyrAsnValValLeuGlnProHisGlnAsnPheLeuLeuPhe435440445GlyAlaAspValValTyrLys450455(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 25 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:AAGCTTGTCGACCAGGCCTTGAGGT25(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 18 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:CTGGAGGCGGTGATGGTG18(2) INFORMATION FOR SEQ ID NO:5:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 19 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:CTCCAGCAGCCACATCAAC19(2) INFORMATION FOR SEQ ID NO:6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 18 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:GAACTTGGTTGTCAGTCG18(2) INFORMATION FOR SEQ ID NO:7:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 13 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:GCCACCRCCATGG13(2) INFORMATION FOR SEQ ID NO:8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:ACTGTCGACGCCACCATGGCCAGGGGC27(2) INFORMATION FOR SEQ ID NO:9:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:CCGCGGCTCGAGCTATATTTTGGTCAT27(2) INFORMATION FOR SEQ ID NO:10:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 16 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:CTGTAGCTCGAGCCGC16(2) INFORMATION FOR SEQ ID NO:11:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 17 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:GGCTCGAGCTACAGAGT17(2) INFORMATION FOR SEQ ID NO:12:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 25 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:GTCGACGCATGCGAGAGAACATGGC25(2) INFORMATION FOR SEQ ID NO:13:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 15 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:GACGCCACCATGGTC15(2) INFORMATION FOR SEQ ID NO:14:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 15 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:GACCATGGTGGCGTC15__________________________________________________________________________

Disclosed are novel bactericidal/permeability-increasing (BPI) protein products wherein cysteine residue number 132 or 135 is replaced by another amino acid residue, preferably an alanine or serine residue and/or wherein the leucine residue at position 193 is the carboxy terminal residue. Also disclosed are DNA sequences encoding methods for the production of the same in appropriate host cells, and stable homogeneous pharmaceutical compositions containing the analogs suitable for use treatment of gram negative bacterial infection and its sequelae.

This is a division of application Ser. No. 745,642, filed Nov. 29, 1976, now U.S. Pat. No. 4,154,617. BACKGROUND OF THE INVENTION Zinc-rich coatings have been described in a current technology review in Modern Paint Coatings, June 1975, pages 19-26. Zinc-rich primers are taught in U.S. Pat. No. 3,505,099 wherein a tetraalkoxy silane is reacted with a strong acid as hydrochloric acid to obtain the hydrolysis product in the presence of water. Partially hydrolyzed silicates are taught in U.S. Pat. No. 3,392,036. U.S. Pat. No. 3,056,684 teaches protective coating containing zinc-rich coating compositions also containing hydrolyzed tetraethyl orthosilicate. Other zinc-rich coating compositions are taught in U.S. Pat. Nos. 3,202,517 and 3,730,743. Priming agents for silicon coatings are also taught in U.S. Pat. No. 3,108,898. U.S. Pat. No. 3,759,852 teaches protective coatings containing glass pigment where the coating composition is normally an organic resin binder vehicle. U.S. Pat. No. 3,634,109 teaches inorganic zinc rich coating compositions containing monoethanolamine plus an organic acid to form salts of said amine. Other references that are teachings in silicon containing compositions are as follows: U.S. Pat. Nos. 2,686,654; 3,108,898; 3,377,309; 3,455,709; 3,560,244 (similar to 3,505,099); 3,615,780; 3,620,784; 3,649,307; 3,721,574; 3,769,050; and 3,784,407. SUMMARY OF THE INVENTION It is an object of the present invention to prepare a silicon containing composition that has a high stability and improved initial hardness over existing compositions. In addition, the silicon containing materials are the basis for coating compositions which have particularly high thermal stability. Described is a process for producing a silicate composition having improved stability comprising the steps: 1. providing a mixture of an organo silicate and/or a partially hydrolysate thereof in a solvent therefor, which solvent is miscible with water; 2. adding a weak acid to said mixture and maintaining the pH acidic, preferably at a range of about 1 to 4; 3. partially hydrolyzing the mixture; and 4. adding a strong acid to said mixture to further hydrolyze the mixture. It has been generally thought in the art that when one adds hydrochloric acid or other strong acid to a tetraethylorthosilicate that gellation would occur. In this case, however, after the initial reaction of the reactant silicate with a weak acid that the use of a strong acid increases the stability of the final product rather than causing gellation. DESCRIPTION OF PREFERRED EMBODIMENT The silicates that may be employed in the present position are generally alkoxy silicate such as tetraalkoxysilicate where the alkyl group ranges from 1 to 10 carbon atoms such as methyl, ethyl, butyl, nonyl and the like. The most preferred silicate is tetraethylsilicate. In the formation of the mixture in the first step of the process, the solvent that may be employed for solubilizing the organosilicate is any solvent that is water miscible. Generally the solvent may be monoalkylene glycol monoalkyl ethers, dialkylene glycol monoalkyl ethers, dialkylene glycol, dialkyl ether and monoalkylene glycol dialkyl ether wherein the alkyl groups preferably range from 1 to 6 carbon atoms and the alkylene groups range from 2 to 4 carbon atoms such as Cellosolve (trademark of Union Carbide for ethylene glycol monoethyl ether), Cellosolve acetate and the like. Other solvents that may be employed are saturated aliphatic ketones such as methylethyl ketone, saturated aliphatic alcohol, such as alkanols of from 1 to 6 carbons as methanol, propanol, butanol and the like. In the first step of the reaction, where the weak acid is added to the mixture of organo silicate in the solvent, an exotherm occurs. Normally the reaction may take place at room temperature, but the temperature is slightly raised due to the exotherm during reaction. If desired, the mixture may be heated to reflux temperature. The weak acid that is employed would be any weak acid that would facilitate the hydrolysis reaction. By "weak acid" is meant any acid which has a pKa value (negative logarithm of the acidic dissociation constant) or more than one (1.0). A "strong" acid is one that has a pKa value of less than one (1.0). While applicant does not wish to be held to any theory, it is believed that the alkoxy group attached to the silicon atom may be replaced by a hydroxyl group. Suitable weak acids are organo carboxylic acid compounds as the mono- or dicarboxylic acids such as carboxylic acids containing up to 12 carbon atoms, including aliphatic and aromatic and cycloaliphatic systems. The aliphatic monocarboxylic acids that may be employed are formic, acetic, pentanoic, and the like, aromatic acids are phthalic (ortho, meta, or para), benzoic and the like. The alphatic dicarboxylic acids are oxalic, malonic, succinic, glutaric, adipic and the like and other polycarboxylic acids as citric and the like wherein the total number of carbon atoms is up to 12. Other weak acids that may be employed are inorganic weak acids such as phosphoric, boric and the like. During the hydrolysis reaction, water is added in a quantity sufficient to give the desired extent of hydrolysis. Preferably, the amount of water that is added is in a range equivalent to 0.30 to 0.95 of the stoichiometric amount needed for complete hydrolysis of the reactant, with 0.95 being the preferred amount. Generally, after the weak acid has been added to the solution, a 24-hour holding period is employed in order to permit the hydrolysis reaction to take place. Thereafter the strong acid is added thereto. The strong acids that may be employed are normally mineral acids such as hydrochloric acid and the like. In general, the reaction time is approximately two hours. Thereafter the product may be used for its normal purpose. After the stabilized product has been obtained it may then be mixed with a particulate metal powder on approximately a 2-4:1 weight basis of metal: condensed silicate composition. The metal has a particulate size ranging from about 4 microns to about 10 microns. The purpose of the metal is to provide a galvanic action coating composition so that as moisture causes corrosion of the object, the metal added to the composition will decompose rather than the substrate upon which the coating has been applied. The metal that may be employed is one that is above iron in the electromotive series such as zinc or aluminum. A glass flake containing composition can also be prepared by mixing the glass flake in the amount of 0.1 to 1.0 parts by weight per part of silicon containing composition. While Applicant does not wish to be held to any theory, it is believed that the glass flakes leaf during the formation of the film. By "leafing" is meant that the glass flakes migrate toward the surface of the film and form a barrier to prevent moisture from moving past the barrier. Leafing glass flakes have been described in U.S. Pat. No. 3,759,852, which is hereby incorporated by reference. While the precise operation of the leafing agent is not know, it has been found desirable to treat commercially available glass flakes with a high molecular weight fatty acid. The glass flakes range in size from micron range to millimeter range. It has been found that an all inorganic silicon coating composition can be formulated employing the glass flakes. The composition can be used to protect metallic substrates susceptible to corrosion. In that situation, one may use any of the usual silicon containing compositions, i.e., the condensation reaction product of water and alkoxy silicates, described above regardless of the method of preparation. More preferably the condensation reaction employs the two-step process described herein, i.e., the reaction with a weak acid and then reacting the product with a strong acid. It is to be appreciated that the silicon containing composition of the present invention may have other non film forming components therein such as pigments, dryers, fillers and the like may be added in accordance with usual custom for formulating a coating for a particular use such as to assist in building up the thickness of the coating. A silicon composition is as follows: ______________________________________ Preferred RangeMaterial Parts/Weight Parts/Weight______________________________________Silicate Reactant 100 1Solvent 50 0.05-1.0H.sub.2 O 10 Less than Stoichiometric amountWeak acid 1 0.01-0.02Strong acid 2-4 0.01-0.06______________________________________ The coating compositions of the present invention may be applied in the normal manner as by roll, dip, spray or brush, with spray application preferred. The coating thickness may range from about 1 to 10 mils. EXAMPLE I ______________________________________ PartsFormulation (by Weight)______________________________________Tetra ethyl ortho silicate 100.010% Citric acid in ethanol (pKa = 3.13) 10.0Ethylene glycol monoethyl ether (anhydrous) 50.0Water 10.037% Hydrochloric acid (pKa = -6.1) 2.5______________________________________ The citric acid solution was added to the previously combined ethylene glycol monoethyl ether and tetra ethyl ortho silicate at 25° C. (ambient room temperature). The water was added and the composition was mixed for five minutes, then the container was sealed and allowed to stand for 24 hours. During this time there was an exotherm and slight pressure build-up. The container was opened and the hydrochloric acid was added. The mixture was agitated for 5 minutes, then resealed. A second exotherm occurred. After cooling, it was ready for use as evidenced by the hard film formed (3 mils-2H hardness) with particulate zinc in a ratio of 3 parts by weight zinc dust to 1 part by weight binder. In both accelerated and actual testing, binder had a shelf life of over two years. EXAMPLE II The binder composition of Example I was mixed with particulate zinc (4-5 microns, calcium-free) in a ratio of 300 parts zinc to 100 parts binder to 15 parts micaceous iron oxide, in a ratio of 250 parts zinc to 100 parts binder to 25 parts fibrous calcium silicate and 350 parts zinc to 100 parts binder to 25 parts micaceous iron oxide to form three finished coating compositions. Each was applied by spray to sandblasted steel substrate. All coatings (3 mils thickness dry) evidenced excellent adhesion, passed salt spray tests as designed by Mil-R-38336, passed hardness tests in less than 1 hour after application and shelf life from extrapolated data indicate a shelf life in excess of two years. EXAMPLE III A binder consisting of tetra ethyl ortho silicate hydrolyzed with only 0.25 equivalent water was prepared as follows: ______________________________________ PartsFormulation by Weight______________________________________Tetra ethyl ortho silicate 100.010% Oxalic acid (pKa = 1.27) 10.0Ethylene glycol monoethyl ether 50.0Water 4.037% Hydrochloric acid (pKa = -6.1) 2.8______________________________________ The oxalic acid solution was added to the previously combined ethylene glycol mono methyl ether and tetra ethyl ortho silicate at 25° C. (ambient room temperature). The water was added and the composition was mixed for five minutes, then the container was sealed and allowed to stand 24 hours. Hydrochloric acid was added and container was then resealed. Composition was ready for use after two hours as evidenced by the hard (2H hardness--3 mils thickness dry) solvent resistant film formed with particulate zinc in a ratio of 3 parts zinc to 1 part binder by weight. Extrapolated data from accelerated testing indicates a shelf life in excess of 3 years. Mixed zinc and binder have a a pot life or working time in excess of 1 week. EXAMPLE IV The composition of Example I was mixed with a leafing glass flake in a ratio 10 parts by weight to 100 parts by weight binder to 0.5 parts by weight zinc oxide, in a ratio of 50 parts by weight glass to 100 parts by weight binder to 0.5 parts by weight zinc oxide and 100 parts by weight glass to 100 parts by weight binder to 0.5 parts by weight zinc oxide to form three finished coating compositions. Each was applied by spray, to sandblasted steel substrate. All coatings (3 mils thickness dry) evidenced excellent adhesion and had good resistance to spot tests of 37% hydrochloric acid, 98% sulfuric acid, 70% nitric acid and glacial acetic acid. EXAMPLE V An example showing the instability of similarly prepared coating compositions (using strong acids) and the inferiority of the zinc-rich coating composition produced therefrom. ______________________________________ PartsFormulation by Weight______________________________________Tetra ethyl ortho silicate 100.037% Hydrochloric acid (pKa = -6.1) 2.7Water 8.3Ethylene glycol monoethyl ether 50.0______________________________________ In accelerated aging tests, this binder had an actual shelf life of less than 2 weeks. A mixture consisting of this binder 1 part by weight to particulate zinc 3 parts by weight gave a coating composition which produced a hard film (2H after 1 hour dry) but pot life or working time was less than 30 minutes and films with thickness exceeding 4 mils "mud-cracked" severely. EXAMPLE VI The binder composition of Example I was mixed with particulate zinc in a ratio of 300 parts zinc to 100 parts binder to 15 parts micaceous iron oxide. This coating composition was applied, by spray, to a sandblasted steel substrate and over-coated with a composition consisting of 100 parts by weight binder composition of Example I, 50 parts by weight glass flake and 0.5 parts by weight zinc oxide. Test results indicate this coating system is resistant to strong acids and temperatures up to and exceeding 1600° F. (871° C.). The binder and zinc alone will not resist strong acids and will oxidize at temperatures exceeding 750° F.

Described is a method for protecting metallic substrates which comprises applying thereto silicon containing compositions produced by the steps of: 1. providing a mixture of an organo silicate or a partial hydrolysate thereof in a solvent therefor; 2. adding a weak acid to said mixture and maintaining the pH acidic, preferably at a range from about 1 to about 4; 3. partially hydrolyzing the mixture; and 4. adding a strong acid to said mixture to further hydrolyze the mixture; and curing the composition. The composition may contain also glass flakes.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable. BACKGROUND OF THE INVENTION [0003] The invention relates to compositions, methods, and apparatuses for improving the inhibition of scale deposition. More specifically, the invention relates to a method of inhibiting scale deposition in process solution distribution systems consisting of piping, spray nozzles, and emitter tubes such as those used in heap leach mining operations. [0004] In heap leach mining operations, a heap of valuable mineral containing ore is placed on a containment liner system (also known as a heap leach pad) and continuously sprayed or irrigated with a process solution, commonly referred to as barren solution, to wet the entire ore heap. The barren solution selectively extracts or leaches the valuable mineral(s) in the ore as the solution infiltrates through the ore heap. Thesolution collected after leaching which contains the targeted ,valuable mineral(s) is known as pregnant solution. The pregnant solution is collected at the bottom of the ore heap and is transported to processing equipment, where the targeted valuable mineral(s) are selectively separated or recovered and barren solution is recycled to the heap. If lower than desired targeted mineral concentration is achieved in the pregnant solution, this solution, often referred to a lean pregnant solution, can be recycled to the heap for further leaching. [0005] One problem commonly faced in heap leach mining operations is the precipitation and accumulation of mineral scale deposits in process solution distribution systems. Such scale impairs or clogs the flow of the process solution which can result in such problems as incorrect or inadequate dosage of barren or lean pregnant solution added to the heap, damage to solution distribution systems, loss of effectiveness of the solution, and increased energy needed to pump the solution through the solution distribution system. Currently such problems are addressed by feeding scale control reagents to protect the solution distribution system against mineral scale related plugging or damage, and to assure adequate flow rates. [0006] The quantity or dosage of scale control reagent required for effective deposit control is dependent upon soluble mineral concentrations in the process solution in combination with physical stresses that impact saturation levels. Saturation levels are often highly variable impacted by variations in ore subjected to leach, make-up water volume and composition, process additive rates, and physical stress changes. Dosage rates of scale control reagent are however commonly held constant, often resulting in overdose (reagent waste) or under dose (inadequate control of scale) as conditions vary. [0007] There thus exists an ongoing need to develop alternative and more efficient methods of controlling scale control reagent dosages applied to process solution distribution systems including those used in heap leach mining operations. [0008] The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 CFR § 1.56(a) exists. BRIEF SUMMARY OF THE INVENTION [0009] To satisfy the long-felt but unsolved needs identified above, at least one embodiment of the invention is directed towards a method of inhibiting the accumulation of scale on a surface in contact with a liquid medium. The method comprises the steps of: providing an solution distribution system comprising one or more of: piping, spray nozzles, emitter tubes, and any combination thereof having a length which defines more than one discrete region, each discrete region capable of having different surface temperatures; positioning at least one temperature sensor such that it is constructed and arranged to measure or predict the maximum surface temperature across all discrete regions within the solution distribution system; and applying a scale control reagent to a specific location in the solution distribution system when the measured or predicted surface temperature at that location exceeds a threshold required to initiate inverse solubility scale formation, at a reagent dosage required to prevent scale formation [0010] Additional features and advantages are described herein, and will be apparent from, the following Detailed Description. BRIEF DESCRIPTION OF THE DRAWINGS [0011] A detailed description of the invention is hereafter described with specific reference being made to the drawings in which: [0012] FIG. 1 is an illustration of using an aspect of the invention to address scale in a heap leach mining operation. [0013] For the purposes of this disclosure, like reference numerals in the figures shall refer to like features unless otherwise indicated. The drawings are only an exemplification of the principles of the invention and are not intended to limit the invention to the particular embodiments illustrated. DETAILED DESCRIPTION OF THE INVENTION [0014] The following definitions are provided to determine how terms used in this application, and in particular how the claims, are to be construed. The organization of the definitions is for convenience only and is not intended to limit any of the definitions to any particular category. [0015] “Consisting Essentially of” means that the methods and compositions may include additional steps, components, ingredients or the like, but only if the additional steps, components and/or ingredients do not materially alter the basic and novel characteristics of the claimed methods and compositions. [0016] “Scale Control Reagent” means chemical reagents commonly applied for prevention of mineral scale deposition in aqueous solution environments falling in the general categories of threshold inhibitors, crystal modifiers, dispersants, sequestering agents, and or chelants. Common reagents may contain any combinations of these generic constituents. [0017] “Heap Leaching” means an industrial mining process to extract precious metals including but not limited to copper, gold, silver, uranium, rare earth metals and other compounds from ore via the application to a heap of the ore of one or more liquid form chemical reagents that percolate through the heap and while so doing absorb specific minerals which then seep out of the heap. [0018] “Emitter Tube” means a tube or flow line constructed and arranged to transport one or more fluids to a target area (such as for example an ore heap) and to allow for the application (often by dripping) of the fluid onto the target area. [0019] In the event that the above definitions or a description stated elsewhere in this application is inconsistent with a meaning (explicit or implicit) which is commonly used, in a dictionary, or stated in a source incorporated by reference into this application, the application and the claim terms in particular are understood to be construed according to the definition or description in this application, and not according to the common definition, dictionary definition, or the definition that was incorporated by reference. In light of the above, in the event that a term can only be understood if it is construed by a dictionary, if the term is defined by the Kirk-Othmer Encyclopedia of Chemical Technology, 5th Edition, (2005), (Published by Wiley, John & Sons, Inc) this definition shall control how the term is to be defined in the claims. [0020] At least one embodiment of the invention is directed towards the prevention of the formation and/or accumulation of scale in process solution distribution systems. Specifically the tendency of scale to form or accumulate at a specific localized spot along emitter tube's length, or in piping leading to the emitter tubes which may break loose and accumulate in the emitter tubes is identified and may be remedied, Piping and emitter tubes are commonly laid out in open areas where they allow for the gradual dripping of barren or lean pregnant solution onto a target area. These pipes and emitter tubes are often exposed to direct sunlight, sometimes in hot, sun intensive climates. In addition the specific materials the solution distribution systems are constructed out of can have high thermal absorbtion properties resulting in heat absorption and transfer to the inner wall of piping and emitter tubes. The cumulative effect is that specific localized portions of the piping and emitter tubes can become hot enough to effect inverse temperature solubility of many scale producing materials. For these materials when the temperature exceeds a threshold precipitation results. [0021] With exposed piping and emitter tubes, the bulk solution as whole may have an average temperature that is below the threshold for scale formation, but localized pipe and emitter tube surface temperatures where solution contact occurs may be substantially hotter such that localized precipitation and scaling occurs. Once scale starts to form on these surface(s), the established scale can function as a seed or anchor on which more scale can rapidly accumulate. [0022] In at least one embodiment prediction or measurement of piping and emitter tube heat transfer intensity can be utilized to predict scale control reagent dosage requirements. In at least one embodiment the scale produced is at least in part a result of exposure to sunlight and is therefore broadly predicted based upon ambient temperature, temperature change rates, and commonly available weather related measurements. In at least one embodiment the scale produced is at least in part a result of heat transfer resulting in solution temperature elevation and therefore localized heat intensity prediction may include bulk solution temperatures at various point in the solution distribution system, and temperature change rates. [0023] In at least one embodiment temperature measurement using a detector or a device that can be used to infer a spike in temperature are used to determine the degree to which process piping or emitter tube's surfaces are being subjected to temperature elevation. In at least one embodiment scale control reagents are fed to a location where it has been. detected that temperature is such that scale would form. In at least one embodiment chemicals are only fed in such an amount or dosage to address the scale in the specific location. so detected. In at least one embodiment scale controlling chemicals are fed to a location where the temperature has exceeded the threshold for formation but insufficient time has elapsed for detectable amounts of scale to form. [0024] In at least one embodiment the emitter tube is part of a heap leach mining operation. Representative examples of heap leach mining operations the invention may be used within and how emitter tubes are located therein are described at least in U.S. Pat. Nos. 5,030,279 and 4,960,584 and in U.S. Published Patent Application 2013/0125709. [0025] In at least one embodiment the scale producing heat is at least in part a result of exposure to sunlight and is therefore detected via one or more sunlight measuring or detecting optical sensors. The sensor may be constructed and arranged to measure sunlight intensity and to calculate from that if the temperature of one or more localized locations along the emitter tube will exceed the threshold required for scale formation. [0026] In at least one embodiment scale control reagent dosage is automatically adjusted if such a determination is made. [0027] In at least one embodiment the temperature sensor is one item selected from the list consisting of: thermocouple, resistive temperature device, infrared detector, bimetallic device, liquid expansion device, and any combination thereof. [0028] Referring now to FIG. 1 there is shown an application of the invention. Ore is collected into a heap ( 1 ) lying on a pad ( 4 ). Onto the heap barren solution ( 2 ) is fed via a process distribution system which may comprise a series of emitter tubes each with one or more opening in an emitter tube ( 3 ) and which may open into one or more nozzles. As the solution percolates through the heap ( 1 ) it leaches or solubilizes valuable minerals into pregnant solution which is collected and transferred to a processing plant where the valuable mineral ( 8 ) is then separated from the reagent through one or more recovery processes ( 6 ). In some operations multiple pad area are under leach simultaneously or intermittently, and low concentration pregnant solutions may be recycled back to the heap for additional leaching. [0029] Because of such variables as tube shape, position, exposure to elements, exposure to sunlight, etc. it is quite likely that the surface of pipint and emitter tubes at one location will become hotter than another location and will become an anchor for scale formation. As a result respectively located sensors may be used to detect localized temperature spikes that can cause scale. [0030] In at least one embodiment the dosage of the scale control reagent ( 7 ) is so dosed as to assure that adequate dosage of scale control reagent is applied under high temperature stress conditions, and that reduced dosage is applied when temperature stress is relieved. [0031] In at least one embodiment the scale comprises at least in part CaCO 3 or other common mineral scale forming compound [0032] In at least one embodiment the scale control reagent is applied according to the methods described in U.S. Pat. No. 5,368,830. [0033] In at least one embodiment in response to the detection and/or anticipation of at least one localized hot spot in at least a portion of a process distribution system a scale control reagent is introduced into the process distribution system. Such an introduced reagent may be directed to: the localized hot spot, some overall percentage of the process distribution system, or throughout the entire process distribution system. The reagent may be introduced such that it is present wherever the barren solution is also present within the process distribution system. The reagent may be fed in such a manner that it remains present within the hot spot or other portions of the process distribution system for some or all of the time that the detected and/or anticipated temperature spike is manifest. In at least one embodiment the reagent can then be gradually or rapidly cut off from the process distribution system as the localized temperature spike declines or disappears. [0034] In at least one embodiment a hot simulator is used increase the effectiveness and/or efficiency of a sensor or anticipation method. Often in process distribution systems the pumps that feed reagent or other materials into the pipes and tubes are located quite a distance from the emitter tubes or nozzles, this distance can be 1, 2-10, or more miles. In a hot simulator a section of tubing made from the identical materials as an emitter tube or nozzle and is located within 1000 feet of a pump and affixed to it is a heat sensor. This tubing may or may not be in fluidic communication with the process distribution system and will mirror what is happening downstream in the process distribution system. The closely positioned tubing allows for monitoring of heat spikes without the need for complicated wired or wireless transmission systems. In at least one embodiment scale control reagent is fed into at least a portion of the process distribution system in response to a measurement of a heat spike in a hot simulator and/or in response to the anticipation of a heat spike in a hot simulator. While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. All patents, patent applications, scientific papers, and any other referenced materials mentioned herein are incorporated by reference in their entirety. Furthermore, the invention encompasses any possible combination of some or all of the various embodiments mentioned herein, described herein and/or incorporated herein. In addition the invention encompasses any possible combination that also specifically excludes any one or some of the various embodiments mentioned herein, described herein and/or incorporated herein. [0035] The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims. [0036] All ranges and parameters disclosed herein are understood to encompass any and all subranges subsumed therein, and every number between the endpoints. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of I or more, (e.g. 1 to 6.1.), and ending with a maximum value of 10 or less, (e.g. 2.3 to 9.4, 3 to 8, 4 to 7), and finally to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 contained within the range. All percentages, ratios and proportions herein are by weight unless otherwise specified. [0037] This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.

The invention provides methods, compositions, and apparatuses for preventing the formation of scale in heap leach process solution distribution systems comprised of piping, spray nozzels, or emitter tubes. Solution distribution system components often become fouled by scale because of local hot spots more prone to form scale than other locations along the systems length. Positioning sensors that detect periods of high temperature stress and adjusting scale control reagent dosage to send the right amount to inhibit hot spot deposition allows for the control of scale without using wasteful excessive amounts of scale control reagents. This can vastly improve scale control performance under high temperature stress conditions while minimizing scale control reagent waste under less severe stress conditions to reduce the total operating cost of running heap leach mining operations which depend upon well-functioning solution distribution systems

FIELD OF THE INVENTION [0001] The present invention relates to a data active on-demand-transmission system, wherein by communication transmission technology, the data catalogue of the service provider is actively transferred to a personal digital assistant for being browsed and selected by the personal digital assistant. BACKGROUND OF THE INVENTION [0002] With the progress of technology, under the combination of customer' electronic products and communication technology, the speeds of data transmission, for example broadcasts, televisions, telephones, and others are quicker and quicker, so that the human life is varied quickly by both wireless or wired communication. Of course, this improvement is necessary and beneficial. This has a greater effect to commerce. [0003] In a communication transmission, there is a supply end and a demand end so as to be connected and then be formed as an integrated structure. FIG. 1 is a block schematic view showing in the conventional technology for transferring a data signal, the demand and supply ends are represented by a plurality of customer ends 10 , 14 . Each of the customer ends 10 , 14 may be a demand end or a supply end demand on the input or output. A servo and a plurality of base stations 11 , 13 are includes in the plurality of customer ends. The data from the customers are processed and transferred through the servos 12 and the plurality of base station 11 and 13 so as to achieve the object of communication. [0004] The abovesaid is a simplest process in communication. However, this is a passive service which is not satisfied by the consumers. Although, the customer's end 10 and 14 can be replaced by service providers, but it is also confined in a supply way of supplying for a demanding request. In order to provide an optimum service quality, a better system service module is necessary. SUMMARY OF THE INVENTION [0005] Accordingly, the primary object of the present invention is to provide a data active on-demand-transmission system for solving the defects in the prior art. In the present invention, the service required by the customer is provided to the customers without interfering customers. The customer need not disclose a request for acquiring a service catalogue. [0006] Another object of the present invention is to provide a data active on-demand-transmission system, in the aforesaid prior art, a plurality of customer ends transfer data through servos and base stations. The plurality of customers may be a servo of the system service provider. By the servos and base stations to transfer data, the required service is provided to the connected customer end. In the present invention, in the flow process for each component of the data catalogue between the serve and customer end is controlled so that the servo may actively provides required service to the customers Thus, the customers may select conveniently. [0007] Preferably, a system servo between the servo and the receiving end serves to receive all data from the servo, after arrangement and integration, a proper data catalogue is formed. Then, a proper designed transmission interface transfers the data catalogue to the customer receiving end for being browsing by the customer. [0008] Preferably, in the data processing of the data active on-demand-transmission system of the present invention, after receiving a data, then the data is arranged and integrated, it is transferred through a transmission interface, and then is browsed by the customer. [0009] Preferably, after the customer receives the data catalogue, the service provider provides product catalogue and then is displayed on a screen. Then, the customer instructs a selection command, the order data is transferred and acknowledge operation is performed. [0010] Preferably, by using a broadcast technology and a one-to-many transmission protocol, data catalogue is actively transferred to an objected receiving end. Therefore, the resource of bandwidth consumed in bidirectional transmission is saved. Furthermore, in an active transmission, by an on-demand transmission protocol, a optimum integration and adjustment are performed between the demand end and the supply end. [0011] Preferably, in the present invention, by Internet to transfer data catalogue, or by a personal digital assistant to receive the data catalogue from wireless transmission, the customers can select service items. Moreover, by the wireless application protocol (WAP), the data active on-demand-transmission system of the present invention can be achieved. [0012] The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing. BRIEF DESCRIPTION OF THE DRAWINGS [0013] [0013]FIG. 1 is a block schematic view of a communication transmission in one embodiment of the present invention. [0014] [0014]FIG. 2 is a front schematic view for the application of personal digital assistant in the present invention, [0015] [0015]FIG. 3 is a block schematic view for the communication transmission in the embodiment of the present invention. [0016] [0016]FIG. 4 is a schematic view about the data processing in the embodiment of the present invention [0017] [0017]FIG. 5 is a flow diagram showing an acknowledge of order in the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0018] In the data active on-demand-transmission system of the present invention, a proper receiving servo, such as personal digital assistant (PDA), displays a catalogue data. Then, the selected service item is transferred back to the service, provider for performing proper work. When providing catalogue data, the customer is unnecessary to inform network system service provider about the required data. These data is directly provided by the network service provider for improving the quality of service and the time consumed by the customer is reduced. [0019] Since the present invention is about a processing system in the communication transmission, in practical application, it needs to use a wireless or wired consumer's electronic devices, such as mobile phones, pagers, Internet, and others. In the embodiment of the present invention, a multiple-functional personal digital assistant is used. With reference to FIG. 2, a personal digital assistant is employed in this embodiment. It is appreciated that the personal digital assistant includes a display screen 20 which displays the data catalogue. A direction selection unit 21 and an input key 22 are formed below the display screen 20 . The direction selection unit 21 is installed with a left key 23 , a right key 26 , an up key 25 , a down key 25 . The keys 23 , 24 , 25 and 26 serve to control the movement of cursor. As the selection work is accomplished, the input key 22 serves to select working item. The personal digital assistant further includes a sensor pen 27 . By directly touching the items on the display screen 20 , a respective work is performed. [0020] Referring to FIG. 3, a block schematic view for one embodiment of the present invention is illustrated. It is appreciated that in the communication transmission, all the data catalogue is provided by the data servo end 30 , and a system servo serves to integrate the data. A first transmission interface 32 serve to play the data. The customer receiving end 34 is used to receive and display the data catalogue. In the customer receiving end 34 , a personal digital assistant 20 in FIG. 2 is employed to receive and display the data catalogue. [0021] In FIG. 3, a signal transmission is performed between the system servo 31 and customer receiving end 34 . The system servo 31 receives and integrates the catalogue data from the data servo 30 . By a proper transmission interface, the catalogue data is actively transmitted to the personal digital assistant of the customer receiving end 34 . The transmission interface has a first transmission interface 32 and a second transmission interface 33 . The system servo 31 receives the catalogue data from the data servo. The data catalogue is transferred by a proper transmission interface. The first transmission interface 32 has a one-to-many transmission mode. By an active transmission, the signals are transferred to many customers 34 . The second transmission interface 33 performs a one-to-one transmission by a system setting in the customer receiving end 34 . By the data transmission mode in the second transmission interface, the transmission data is kept secret. [0022] The catalogue data transferred by the first transmission interface 32 is selected and confirmed. Then, the signal is output through the signal transmitting unit in the personal digital assistant of the customer receiving end 34 to inform the system servo 31 to analyze the signal and proper processing work is returned back to the data servo 30 . Therefore, in performing a work, the system servo 31 performs a proper data processing by the frequent communication between the data servos. It actively and continuously transfers data catalogue to the customer receiving end 34 by the second transmission interface. In the customer receiving end 34 , the selected data item is transferred back to the system servo 31 . The selected data catalogue is transferred back to the system servo 31 . The selected data item are transferred directly to the system servo 31 , and the signal transmission is unnecessary to pass through the first transmission interface. [0023] Referring to FIGS. 2 and 3, the personal digital assistant used in the customer receiving end can be connected to an I/O port of a computer through a signal transmission line. After setting a communication protocol, the data is transferred through a communication module of Internet. As the signal is transferred, an application specific integrated circuit (ASIC) is installed in the personal digital assistant. This application specific integrated circuit outputs proper selecting items for providing a one to one acknowledge operation. [0024] Referring to FIG. 4, a schematic view of the data processing in the embodiment of the present invention is illustrated. The system servo outputs all data to the system servo. The system servo performs the following operation for transferring data catalogue to the customer receiving end; [0025] 1. Date input: the data servo output catalogue data, and the system servo serves to input data. [0026] 2. Data arrangement: the catalogue data is put in order and classified for expanding the catalogue contents of the data catalogue. [0027] 3. System integration: an stacking work for transmission data is performed and then the data is transferred to the transmission interface. [0028] 4. Transmission: The data is transferred through a transmission channel. [0029] 5. The customer receives the signal. [0030] In the step of data processing, the system servo classifies the catalogue data and by a trellis classify structure, the system construction is arranged in order, As the data is transferred and played, by wired and wireless transmission technology, the data transmission is performed, [0031] Referring to FIG. 5, a flow diagram for assuring an order in the embodiment of the present invention is illustrated. The customer receiving end receives the data catalogue actively transferred from the transmission interface, then the acknowledgement of an order is processed by following step: [0032] 1. Display product catalogue, the display screen of the personal digital assistant of the customer receiving end displays the data catalogue processed by the system servo. [0033] 2. The order selection: a selection operation is performed through a selection way provided by the personal digital assistant. If the selection work is not performed, the system servo actively transfers data catalogue by a proper transmission interface. [0034] 3. Transmission of ordering data: after the customer accomplishes the selection operation for ordering, then the proper signal output is performed by a personal digital assistant. [0035] 4. Verification operation: the system servo verifies the transferred order data. If the data is wrong, then the customer selection operation is re-performed. [0036] 5. Order verification: assure that the order is correct, and the overall operation is complete. [0037] In the order acknowledge step illustrated in FIG. 5, a special series number in the application specific integrated circuit (ASIC) in the personal digital assistant is used to provide an acknowledge number at the order acknowledge work. [0038] The present invention is thus described, it will be obvious that the same may be varied in many ways. In practical application, the present invention is not confined to be accomplished by a personal digital assistant. Since the progressive of the current communication technology, the transmission mode of the present invention can be used in the transmission of the computer Internet or wireless application protocol (WAP) in the mobile phones, or general pagers, cable TVs. The system service provider can provide the information and service required by the customers to the customers. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

The convention transmission method is an on-demand data communication, in which one discloses a demand and one provides a supply. However, this communication way is not suitable nowadays. Since amount of current data transmission is very large. In order to improve the quality in service, the service provider provides actively the required service to the customer. After browsing by the customer, then the customer transfers the selection items to the service provider and then the service provider provides required service to the customers, By this way, the customer may browse products rapidly and the quality of information service is improved.

BACKGROUND [0001] The present invention relates to compounds of formula [0002] Compounds of the present invention are NMDA(N-methyl-D-aspartate)-receptor subtype selective blockers. [0003] Under pathological conditions of acute and chronic forms of neurodegeneration overactivation of NMDA receptors is a key event for triggering neuronal cell death. NMDA receptors are composed of members from two subunit families, namely NR-1 (8 different splice variants) and NR-2 (A to D) originating from different genes. Members from the two subunit families show a distinct distribution in different brain areas. Heteromeric combinations of NR-1 members with different NR-2 subunits result in NMDA receptors displaying different pharmaceutical properties. Possible therapeutic indications for NMDA NR-2B receptor subtype specific blockers include acute forms of neurodegeneration caused, e.g., by stroke and brain trauma, and chronic forms of neurodegeneration such as Alzheimer's disease, Parkinson's disease, Huntington's disease, ALS (amyotrophic lateral sclerosis), neurodegeneration associated with bacterial or viral infections, and, in addition, depression and chronic and acute pain. SUMMARY [0004] A compound of formulae [0005] wherein [0006] R 1 and R 2 are independently selected from the group consisting of hydrogen, lower alkyl, —(CH 2 ) n —OH, —(CH 2 ) n —N(R 6 ) 2 , 13 NR 6 C(O)C(O)O-lower alkyl, —NR 6 _(CH 2 ) n —OH, —NR 6 C(O)-lower alkyl, —NH-benzyl and NR 6 C(O)—(CH 2 ) n —OH; [0007] R 6 is independently hydrogen or lower alkyl; [0008] R′ is hydrogen or lower alkyl; [0009] R 3 is hydrogen or amino; [0010] R 4 is hydrogen or lower alkyl; [0011] R 5 is hydrogen or halogen; or [0012] R 1 and R′ together with the carbon atoms to which they are attached form the group —(CH 2 ) 4 —; or [0013] R 2 and R 3 together with the carbon atoms to which they are attached form the group —N(R 6 )—CH 2 —O—CH 2 —; and [0014] n is 0, 1, 2 or 3; [0015] or a pharmaceutically acceptable acid addition salt thereof. [0016] The compounds of formula IA and IB and their salts are distinguished by valuable therapeutic properties. Compounds of the present invention are NMDA(N-methyl-D-aspartate)-receptor subtype selective blockers, which have a key function in modulating neuronal activity and plasticity. Accordingly, compounds of the invention are useful in mediating processes underlying development of CNS as well as learning and memory formation. [0017] The present invention relates to compounds of formula IA, IB, combinations thereof and pharmaceutically acceptable acid addition salts thereof, and the preparation of the compounds of formula IA, IB and salts thereof. The present invention also relates to pharmacuetical compositions containing a compound of formula IA, IB, combinations thereof or a pharmaceutically acceptable acid addition salt thereof and the preparation of such pharmaceutical compositions. The invention also relates to a method of treatment of diseases responsive to modulation of NMDA(N-methyl-D-aspartate)-receptors by subtype selective blockers, comprising administering a therapeutically effective amount of the compounds of formula IA, IB, combinations thereof or their pharmaceutically acceptable salts to a patient in need of such treatment. DETAILED DESCRIPTION [0018] The following definitions of the general terms used in the present description apply irrespective of whether the terms in question appear alone or in combination. [0019] As used herein, the term “lower alkyl” denotes a straight- or branched-chain alkyl group containing from 1 to 7 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, butyl and the like. Preferred lower alkyl groups contain from 1 to 4 carbon atoms. [0020] The term “halogen” denotes chlorine, iodine, fluorine and bromine. [0021] The term “pharmaceutically acceptable acid addition salts” embraces salts with inorganic and organic acids, such as hydrochloric acid, nitric acid, sulfuric acid) phosphoric acid, citric acid, formic acid, fumaric acid, maleic acid, acetic acid, succinic acid, tartaric acid, methane-sulfonic acid, p-toluenesulfonic acid and the like. [0022] Compounds of formula IA are preferred. [0023] Exemplarly preferred compounds of formula IA, are those wherein R 2 is amino, selected from the group consisting of [0024] 2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amine, [0025] Rac.-2-(4-methyl-3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amine, [0026] 2-(3,4-dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl-amine, [0027] 2-(3,4-dihydro-1H-isoquinolin-2-yl)-1-methyl-pyridin-4-yl-amine, [0028] 2-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-4-yl-amine and [0029] [4-amino-6-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl]-methanol [0030] Other preferred compounds of formula IA are those, wherein R 2 is —NH(CH 2 ) 2 OH. Examples of these preferred compounds are selected from the group consiting of [0031] 2-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amino]-ethanol, [0032] 2-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-4-yl-amino]-ethanol and [0033] 2-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl-amino]-ethanol. [0034] Compounds of formula IA, wherein R 2 is —NH-lower alkyl, are also preferred, for example compounds selected from the group consisting of: [0035] [2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-methyl-amine and [0036] [2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-dimethyl-amine. [0037] Compounds of formula IB are also preferred. [0038] Preferred compounds of formula 113, wherein R 2 is hydrogen, are selected from the (group consisting, of [0039] 2-pyridin-4-yl-1,2,3,4-tetrahydro-isoquinoline and [0040] 2-(2-methyl-pyridin-4-yl)-1,2,3,4-tetrahydro-isoquinoline. [0041] Further preferred compounds of formula IB are those, wherein R 2 is amino, for example compounds selected from the group consisting of: [0042] 4-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl-amine or [0043] 4-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl-amine. [0044] Compounds of formula IB, wherein R 2 is —NHC(O)C(O)OCH 2 CH 3 or —NH(CH 2 ) 2 OH are also preferred and selected from the group consisting of [0045] N-[4-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl]-oxalamic acid ethyl ester and [0046] 2-[4-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl-amino]-ethanol [0047] The compounds of formulae IA and IB can be prepared in accordance with the invention by [0048] reacting a compound of formula [0049] with a compound of formula [0050] forming a compound of formula [0051] wherein R 1 -R 5 and R′ have the significances given above and hal is bromo or chloro, or reacting a compound of formula [0052] with a compound of formula [0053] forming a compound of formula [0054] wherein R 3 -R 5 have the significances given above, or [0055] reacting a compound of formula [0056] with ClC(O)C(O)OCH 2 CH 3 [0057] forming a compound of formula [0058] wherein R 1 , R 3 -R 5 and R′ have the significances given above, or [0059] reducing a compound of formula [0060] with an reducing agent, such as AlLiH 4 /THF [0061] thereby forming a compound of formula [0062] or further reducing compounds IA4 or IB4 to a compound of formula [0063] wherein R 1 , R 3 -R 5 and R′ have the significances given above, or [0064] reacting a compound of formula [0065] with ClC(O)OCH 2 CH 3 or with CH 3 C(O)Cl or with ClC(O)-phenyl or with CHOOH/CH 2 O, respectively [0066] forming a compound of formula [0067] or of formula [0068] or of formula [0069] or of formula [0070] wherein R 1 , R 3 -R 5 and R′ have the significances given above, or [0071] reacting a compound of formulae [0072] with HCOOH/CH 2 O [0073] to give a compound of formulae [0074] wherein R 1 , R 4 , R 5 and R′ have the significances given above, and [0075] if desired, converting the compound of formula I obtained into a pharmaceutically acceptable salt. [0076] In the following the preparation of compounds of formula IA and IB are described in more detail: [0077] In accordance with the process variants, described above, and with schemes 1-12, described below, compounds of formula IA and IB may be prepared by known procedures, for example by the followings: [0078] A mixture of a compound of formula IIA or IIB, for example 2-bromo-pyridin-4-yl-amine or 4-bromo-pyridin-2-yl-amine, respectively, and a compound of formula III, such as 1,2,3,4-tetrahydro-isoquinoline is stirred at 150° C. for about 3 hr. After extractive workup the organic phase is dried and concentrated to give the free base of a compound of general formulae IA or IB. [0079] Compounds of formula IIA1 may be prepared as follow: [0080] To a solution of a compound of formula IIA, for example 2-bromo-6-ethyl-pyridine (S. G. Davies and M. R. Shipton, J. Chem. Soc., Perkin Trans. 1, 1991, 3, 501) in acetic acid is added peracetic acid, maintaining T<50° C. After complete addition the mixture is stirred at about 50° C. for 5 hr and then cooled to rt. Crushed ice is added and the pH is adjusted to pH 12 with aqueous KOH solution. After extraction the combined organic phases are dried and evaporated to give the corresponding oxide of formula IVA. Then, with ice bath cooling HNO 3 is added dropwise, followed by H 2 SO 4 . The mixture is stirred at about 90° C. for 90 min and then cooled to rt. Crushed ice is added and the pH is adjusted to pH 12 with aqueous NaOH solution. After extraction the combined organic phases are dried and evaporated to give a compound of formula VA, wich is directly used in the next step. A solution of a compound of formula VA in acetic acid is treated with powdered iron. The mixture is slowly heated to 100° C. and kept for 1 hr at this temperature. Then the reaction mixture is cooled to rt and filtered. After evaporation of the solvent the residue is crystallized to yield a compound of formula IIA1. [0081] The corresponding compounds of formula IA may be prepared as described above. [0082] Furthermore, compounds of formula IIA2 may be prepared as follows: [0083] To a solution of a compound of formula VA1, for example 2-bromo-6-methyl-4-nitro-pyridine (A. Puszko, Pr. Nauk. Akad. Ekon. im. Oskara Langego Wroclawiu, 1984, 278, 169) in conc. H 2 SO 4 , CrO 3 is added maintaining T<55° C. After about 4 hr the mixture is heated to 70° C. for 30 min and then cooled to rt. Ice-cold water is added maintaining T<70° C. The mixture is left overnight. A compound of formula VA2 is obtained. A corresponding solution of these compounds in THF is treated with borane/THF. The mixture is refluxed for 6 hr, then powdered iron is added, followed by acetic acid. Reflux is maintained for 6 hr, the mixture is filtered, evaporated, partitioned, dried and concentrated to give a compound of formula IIA2. The corresponding compounds of formulae IA may then be prepared as described above. [0084] A compound of formula IIA3 maybe prepared in the following way: With efficient ice bath cooling a compound of formula VI, for example 2-bromo-5,6,7,8-tetrahydro-quinoline I-oxide (S. Zimmermann et al., J. Am. Chem. Soc., 1991, 113, 183) is treated with conc. H 2 SO 4 , followed by conc. HNO 3 . The resulting mixture is heated to about 90° C. for 90 min, cooled and poured on crushed ice. NaOH is added to reach pH 7 and the aqueous phase is extracted, dried and concentrated to yield a compound of formula VII. [0085] A mixture of a compound of formula VII, for example 2-bromo-4-nitro-5,6,7,8-tetrahydro-quinoline 1-oxide, powdered iron and acetic acid is heated to about 100° C. for 1 hr. After cooling the mixture is filtered, evaporated and the residue is partitioned. The organic phase is dried and concentrated to provide a compound of formula IIA3. The corresponding compounds of formulae IA1 may then be prepared as described above. [0086] Furthermore, a compound of formulae IA3 or IB3 may be prepared by reaction of a compound of formula IA2 or IB2, with ethyl chlorooxoacetate. The obtained compound of formula IA3 or IB3 is then reacted with lithium aluminum hydride. After workup and chromatography the free base of a compound of formulae IA4 and IA5 or IB4 and IB5 may be obtained. [0087] Compounds of formula IA9 or IB9 may be prepared as follows: [0088] A solution of a compound of formula IA2 or IB2, for example 2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amine in formic acid is treated with aqueous formaldehyde solution. The mixture is refluxed for 1 hr followed by evaporation of the volatiles. The residue is partitioned and the organic phase is separated, dried and concentrated. [0089] Compounds of formulae IA6, IB63, IA7, IB7, IA8 or IB8 may be obtained from a compound of formula IA2 or IB2 with ethyl chloroformate, acetylchloride or benzoyl chloride, respectively. These reactions are carried out in conventional manner. [0090] In accordance with schemes 11 and 12, a compound of formula IA11 or IB11 or similar compounds maybe prepared from a solution of a compound of formula IA10 or IB10, for example [2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-ethyl-amine, in formic acid This solution is treated with aqueous formaldehyde solution. The mixture is refluxed for 1 hr followed by evaporation of the volatiles. The residue is partitioned and the organic phase is separated, dried and concentrated to obtain a compound of formula IA11 or IB11. [0091] Pharmaceutically acceptable salts can be manufactured according to methods which are known in the art. The acid addition salts of compounds of formula IA and IB are especially well suited for pharmaceutical use. [0092] In the following schemes 1-12 are described processes for preparation of compounds of formula I, starting from known compounds, from commercial products or from compounds, which can be prepared in conventional manner. [0093] The preparation of compounds of formulae IA and IB are described in more detail in working examples 1-35 [0094] The substituents R 1 to R 5 and R′ are described above. [0095] The substituents R 1 to R 5 and R′ are described above. [0096] The substituents R 1 , R 3 and R′ are described above. [0097] The substituents R 1 and R 3 are described above. [0098] The substituents R′ and R 3 are described above. [0099] wherein R 3 -R 5 have the significances given above. [0100] The substituents R 1 , R 3 -R 5 and R′ are described above. [0101] The substituents R 1 and R 3 -R 5 are described above. [0102] The substituents R 1 and R 3 -R 5 are described above. [0103] The substituents R 1 , R 3 -R 5 and R′ have been described above. [0104] The substituents R 1 , R′, R 4 , R 5 and R 6 have been described above. [0105] The substituents R 1 , R 4 and R 5 are described above. [0106] As mentioned earlier, the compounds of formulae IA and IB, combinations of IA and IB and their pharmaceutically usable acid addition salts possess valuable pharmacodynamic properties. Compounds of formulae IA and IB are NMDA-receptor subtype 2B selective blockers, which have a key function in modulating neuronal activity and plasticity. Accordingly, compounds of the invention are useful in mediating processes underlying development of CNS as well as learning and memory formation. [0107] The compounds of formulae IA and IB1 were investigated in accordance with the test given hereinafter. Test Method [0108] 3H-Ro 25-6981 binding (Ro 25-6981 is [R-(R*,S*)]-α-(4-Hydroxy-phenyl)-β-methyl-4-(phenyl-methyl)-1-piperidine propanol) [0109] Male Füllinsdorf albino rats weighing between 150-200 g were used. Membranes were prepared by homogenization of the whole brain minus cerebellum and medulla oblongata with a Polytron (10.000 rpm, 30 seconds), in 25 volumes of a cold Tris-HCl 50 mM, EDTA 10 mM, pH 7.1 buffer. The homogenate was centrifuged at 48,000 g for 10 minutes at 4° C. The pellet was resuspended using the Polytron in the same volume of buffer and the homogenate was incubated at 37° C. for 10 minutes. After centrifugation the pellet was homogenized in the same buffer and frozen at −80° C. for at least 16 hours but not more than 10 days. For the binding assay the homogenate was thawed at 37° C., centrifuged and the pellet was washed three times as above in a Tris-HCl 5 mM, pH 7.4 cold buffer. The final pellet was resuspended in the same buffer and used at a final concentration of 200 mg of protein/ml. [0110] [0110] 3 H-Ro 25-6981 binding experiments were performed using a Tris-HCl 50 mM, pH 7.4 buffer. For displacement experiments 5 nM of 3 H-Ro 25-6981 were used and non specific binding was measured using 10 mM of tetrahydroisoquinoline and usually it accounts for 10% of the total. The incubation time was 2 hours at 4° C. and the assay was stopped by filtration on Whatmann GF/B glass fiber filters (Unifilter-96, Packard, Zurich, Switzerland). The filters were washed 5 times with cold buffer. The radioactivity on the filter was counted on a Packard Top-count microplate scintillation counter after addition of 40 mL of microscint 40 (Canberra Packard S. A., Züirich, Switzerland). [0111] The above procedure was performed to determine data for calculation of an IC 50 value. The IC 50 value is a concentration expressed in micromoles (μM) for a test compound at which 50% of the ligand (in this determination, 3 H-Ro 25-6981) bonded to the receptor is displaced. The binding ability of the compounds of the invention was measured in vitro using a minimum of 10 concentrations and repeated at least once. The specific binding at each concentration was then calculated as the % of the maximum specific binding (100%) obtained in the same experiment, in the absence of a test compound. Competitive displacement of 3 H-Ro 25-6981 was observed, with complete displacement of the radioligand from specific binding sites (usually about 0% of specific binding at the highest concentrations tested). An IC 50 value was then calculated with all the ten datapoints (% of specific bound) by plotting the data on a semilogarithmic scale with a sigmoidal fit (Log of the molar concentration on X-axis vs. % of specific bound on the Y-axis) using Microsoft Excel fit software or Microcal Origin software. The pooled normalized values were analyzed using a non-linear regression calculation program which provide IC 50 with their relative upper and lower 95% confidence limits. [0112] The IC 50 (μM) of preferred compounds of formulae IA and IB, tested in accordance with the above mentioned methods, is <0.02 μM. In table I below some IC 50 values of preferred compounds are shown. TABLE I Example No. IC 50 (μM) 1 0.008 3 0.011 4 0.014 5 0.0053 6 0.011 9 0.006 10 0.011 30 0.004 31 0.02 32 0.011 33 0.02 35 0.004 [0113] The compounds of formulae IA and IB, combinations of formulae IA and IB and their salts, as herein described, can be incorporated into standard pharmaceutical dosage forms, for example, for oral or parenteral application with the usual pharmaceutically acceptable adjuvant materials, for example, organic or inorganic inert carrier materials, such as, water, gelatin, lactose, starch, magnesium stearate, talc, vegetable oils, gums, polyalkylene-glycols and the like. The pharmaceutical compositions can be employed in a solid form, for example, as tablets, suppositories, capsules, or in liquid form, for example, as solutions, suspensions or emulsions. Pharmaceutically acceptable adjuvant materials can be added and include preservatives stabilizers, wetting or emulsifying agents, salts to change the osmotic pressure or to act as buffers. The pharmaceutical compositions can also contain other therapeutically active substances. [0114] The dosage can vary within wide limits and will, of course, be fitted to the individual requirements in each particular case. In the case of oral administration the dosage lies in the range of about 0.1 mg per dosage to about 1000 mg per day of a compound of (general formula I although the upper limit can also be exceeded when this is shown to be indicated. [0115] The following examples illustrate the present invention in more detail. However, they are not intended to limit its scope in any manner. All temperatures are given in degree Celsius. EXAMPLE 1 [0116] 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amine 1:1 Hydrochloride [0117] A mixture of 2-bromo-pyridin-4-yl-amine (0.50 g, 2.9 mmol) and 1,2,3,4-tetrahydro-isoquinoline (1.1 g, 8.7 mmol) was stirred at 150° C. for 3 hr. After extractive workup (AcOEt/HO) the organic phase was dried (Na 2 SO 4 ), concentrated and chromatographed (SiO 2 with CH 2 Cl 2 /CH 3 OH/NH 4 OH=140/10/1) to give the free base of the title compound (0.39 g, 60%) as a colorless oil. Treatment with hydrogen chloride gave white crystals. Mp. 252° C. (dec.) (isopropanol/AcOEt), MS: m/e=226 (M+H + ). EXAMPLE 2 [0118] Rac.-2-(4-Methyl-3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amine 1:1 fumarate [0119] Following the general method described in example 1, the title compound was obtained as a white crystalline material by reaction of 2-bromo-pyridin-4-yl-amine with rac.-4-methyl-1,2,3,4-tetrahydro-isoquinoline (G. Grunewald et al., J. Med. Chem., 1988, 31, 433) and crystallization of the free base as the fumarate salt. Mp. 178-179° C. (MeOH/Et 2 O), MS: m/e=239 (M + ). EXAMPLE 3 [0120] 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl-amine 1:1 Fumarate [0121] Following the general method described in example 1, the title compound was obtained as a white crystalline material by reaction of 2-bromo-5-methyl-pyridin-4-yl-amine (A. Puszko, Z. Talik, Pr. Nauk. Akad. Ekon. im. Oskara Langego Wroclawiu, 1980, 167, 177) with 1,2,3,4-tetrahiydro-isoquinoline and crystallization of the free base as the fumarate salt. Mp. 110° C. (dec.) (MeOH/Et 2 O), MS: m/e=240 (M+H + ). EXAMPLE 4 [0122] 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-4-yl-amine 1:1 Fumarate [0123] Following the general method described in example 1, the title compound was obtained as a white crystalline material by reaction of 2-bromo-6-methyl-pyridin-4-yl-amine (A. Puszko, Pr. Nauk. Akad. Ekon. im. Oskara Langego Wroclawiu, 1984, 278, 169) with 1,2,3,4-tetrahydro-isoquinoline and crystallization of the free base as the fumarate salt. Mp. 110° C. (dec.) (MeOH/Et 2 O), MS: m/e=239 (M + ). EXAMPLE 5 [0124] 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-ethyl-pyridin-4-yl-amine 1:1 Fumarate [0125] b) 2-Bromo-6-ethyl-pyridine 1-oxide [0126] To a solution of 2-bromo-6-ethyl-pyridine (15.4 g, 82.8 mmol) (S. G. Davies and M. R. Shipton, J. Chem. Soc., Perkin Trans. 1, 1991, 3, 501) in acetic acid (15 ml) was added peracetic acid (26 ml of a 39% solution) maintaining T<50° C. After complete addition the mixture was stirred at 50° C. for 5 hr and then cooled to room temperature (rt). Crushed ice (40 g) was added and the pH was adjusted to pH 12 with 40% aqueous KOH solution. After extraction with CHCl 3 (6×60 ml) the combined organic phases were dried (Na 2 CO 3 ) and evaporated to give 20.0 g (>100%) of the title compound, MS: m/e=201 (M + ) as a yellow oil. [0127] b) 2-Bromo-6-ethyl-4-nitro-pyridine 1-oxide [0128] With ice bath cooling HNO 3 (100%, 25 ml) was added dropwise to 2-bromo-6-ethyl-pyridine 1-oxide (example 5a) (20.0 g, 99 mmol), followed by H 2 SO 4 (98%, 17 ml). The mixture was stirred at 90° C. for 90 min and then cooled to rt. Crushed ice (500 g) was added and the pH was adjusted to pH 12 with 28% aqueous NaOH solution. After extraction with AcOEt (4×250 ml) the combined organic phases were dried (Na 2 CO 3 ) and evaporated to give 15.9 g (65%) of a yellow solid mass which was directly used in the next step [0129] c) 2-Bromo-6-ethyl-pyridin-4-ylamine [0130] A solution of 2-bromo-6-ethyl-4-nitro-pyridine 1-oxide (example 5b) (15.9 g, 69 mmol) in acetic acid (310 ml) was treated with powdered iron (25.8 g, 462 mmol). The mixture was slowly heated to 100° C. and kept for 1 hr at this temperature. Then the reaction mixture was cooled to rt and filtered. After evaporation of the solvent the residue was crystallized to yield the title compound as a beige material (88%). Mp. 75-77° C. (pentane), MS: m/e=200 (M 1 ). [0131] d) 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-ethyl-pyridin-4-yl-amine 1:1 Fumarate [0132] Following the general method described in example 1, the title compound was obtained as a white crystalline material by reaction of 2-bromo-6-ethyl-pyridin-4-yl-amine (example 5c) with 1,2,3,4-tetrahydro-isoquinoline and crystallization of the free base as the fumarate salt. Mp. 140-141° C. (AcOEt), MS: m/e=254 (M+H + ). EXAMPLE 6 [0133] [4-Amino-6-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl]-methanol [0134] a) 6-Bromo-4-nitro-pyridine-2-carboxylic Acid [0135] To a solution of 2-bromo-6-methyl-4-nitro-pyridine (17.8 g, 82.0 mmol) (A. Puszko, Pr. Nauk. Akad. Ekon. im. Oskara Langego Wroclawiu, 1984, 278) 169) in conc. H 2 SO 4 (100 ml) CrO 3 (32.8 g, 328 mmol) was added maintaining T<55° C. After 4 hr the mixture was heated to 70° C. for 30 min and then cooled to rt. Ice-cold water (500 ml) was added maintaining T<70° C. The mixture was left overnight. The title compound crystallized as a beige material (76%). Mp. 173-175° C. (H 2 O), MS: m/e=246 (M + ). [0136] b) (4-Amino-6-bromo-pyridin-2-yl)-methanol [0137] A solution of 6-bromo-4-nitro-pyridine-2-carboxylic acid (example 6a) (6.60 g, 29.1 mmol) in THF (150 ml) was treated with borane/THF (87 ml of a 1M solution). The mixture was refluxed for 6 hr, then powdered iron (16.3 g, 291 mmol) was added, followed by acetic acid (150 ml). Reflux was maintained for 6 hr, the mixture was filtered, evaporated and partitioned (AcOEt/NaHCO 3 -solution). The organic phase was dried (Na 2 SO 4 ), concentrated and chromatographed (SiO 2 with CH 2 Cl 2 /MeOH=93/7) to provide 2.0 g (34%) of (4-amino-6-bromo-pyridin-2-yl)-methanol as a white solid material. Mp. 144-145° C. (AcOEt), MS: m/e=202 (M 1 ). [0138] c) [4-Amino-6-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl]-methanol [0139] Following the general method described in example 1, the title compound was obtained as an off-white crystalline material by reaction of (4-amino-6-bromo-pyridin-2-yl)-methanol (example 6b) with 1,2,3,4-tetrahydro-isoquinoline. Mp. 183-184° C. (AcOEt), MS: m/e=255 (M 1 ). EXAMPLE 7 [0140] 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-5,6,7,8-tetrahydro-quinolin-4-yl-amine 1:1 Hydrochloride [0141] a) 2-Bromo-4-nitro-5,6,7,8-tetrahydro-quinoline 1-oxide [0142] With efficient ice bath cooling 2-bromo-5,6,7,8-tetrahydro-quinoline 1-oxide (8.0 g, 35 mmol) (S. Zimmermann et al., J. Am. Chem. Soc., 1991, 113, 183) was treated with conc. H 2 SO 4 (65 ml), followed by conc. HNO 3 (10 ml). The resulting mixture was heated to 90° C. for 90 min, cooled and poured on crushed ice (200 g). NaOH (28%) was added to reach pH 7 and the aqueous phase extracted with AcOEt. The organic phase was dried (Na 2 SO 4 ) and concentrated to yield 7.9 g (83%) of the title compound as a yellow oil. MS: m/e=272 (M + ). [0143] b) 2-Bromo-5,6,7,8-tetrahydro-quinolin-4-yl-amine [0144] A mixture of 2-bromo-4-nitro-5,6,7,8-tetrahydro-quinoline 1-oxide (example 7a) (7.9 g, 28.9 mmol), powdered iron (13.3 g, 238 mmol) and acetic acid (160 ml) was heated to 100° C. for 1 hr. After cooling the mixture was filtered and evaporated and the residue was partitioned (AcOEt/NaHCO 3 -solution). The organic phase was dried (Na 2 SO 4 ), concentrated and chromatographed (SiO 2 with CH 2 Cl 2 /MeOH=98/2) to provide 2.4 g (37%) of the title compound as a brown solid material. MS: m/e=226 (M + ). [0145] c) 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-5,6,7,8-tetrahydro-quinolin-4-yl-amine 1:1 Hydrochloride [0146] Following the general method described in example 1, the title compound was obtained as an off-white crystalline material by reaction of 2-bromo-5,6,7,8-tetrahydro-quinolin-4-ylamine (example 7b) with 1,2,3,4-tetrahydro-isoquinoline and crystallization of the free base as the hydrochloride salt. Mp. 109-110° C. (MeOH/Et 2 O), MS: m/e=279 (M + ). EXAMPLE 8 [0147] N-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-4-yl]-oxalamic Acid Ethyl Ester [0148] With ice bath cooling, a solution of ethyl chlorooxoacetate (2.0 g, 14.6 mmol) in THF (25 ml) was dropwise added to a solution of 2-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-4-yl-amine (example 4) (2.9 g, 12.1 mmol) in pyridine (40 ml). The mixture was stirred at 75° C. for 1 hr, evaporated and partitioned (AcOEt/NaHCO 3 -solution). The organic phase was dried (Na 2 SO 4 ), concentrated and crystallized yielding 3.1 g (75%) of the title compound as light brown solid. Mp. 128-129° C. (AcOEt), MS: m/e=340 (M+H 4 ). EXAMPLE 9 [0149] 2-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amino]-ethanol 1:1 Hydrochloride [0150] a) N-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-oxalamic Acid Ethyl Ester 1:1 Hydrochloride [0151] Following the general method described in example 8, the title compound was obtained as a white crystalline material by reaction of 2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-ylamine (example 1) with ethyl chlorooxoacetate followed by crystallization of the hydrochloride salt. Mp. >187° C. (dec.)(EtOH/Et 2 O), MS: m/e=326 (M+H + ). [0152] b) 2-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amino]-ethanol 1:1 Hydrochloride [0153] A solution of N-[2-(3,4-dihydro-1 H-isoquinolin-2-yl)-pyridin-4-yl]-oxalamic acid ethyl ester (example 9a) (1.3 g, 4.1 mmol) in THF (41 ml) was cooled in an ice bath and lithium aluminum hydride (0.31 g, 8.2 mmol) was added in 5 portions. The mixture was refluxed for 2 hr, quenched with saturated aqueous Seignette-salt solution and diluted with AcOEt (200 ml). The organic phase was separated, dried (Na 2 SO 4 ) and concentrated. After chromatography (SiO 2 with CH 2 Cl 2 /CH 3 OH/NH 4 OH 140/10/1) the free base of the title compound was obtained as a colorless oil (0.79 g, 72%). Treatment with hydrogen chloride and triturating with hexane gave the title compound as a white hygroscopic foam. MS: m/e=270 (M+H + ). EXAMPLE 10 [0154] 2-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-4-yl-amino]-ethanol 1:1 Hydrochloride [0155] Following the general method described in example 9, N-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-4-yl]-oxalamic acid ethyl ester (example 8) was reacted with lithium aluminum hydride. After workup and chromatography the free base of the title compound was treated with an aliquot of 0.1 N hydrochloric acid, filtered and freeze-dried. MS: m/e=284 (M+H + ). EXAMPLE 11 [0156] 2-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl-amino]-ethanol 1:1 Fumarate [0157] a) N-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl]-oxalamic Acid Ethyl Ester [0158] Following the general method described in example 8, the title compound was obtained as a white crystalline material by reaction of 2-(3,4-dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl-amine (example 3) with ethyl chlorooxoacetate. Mp. 110-111° C. (AcOEt), MS: m/e=340 (M+H 1 ). [0159] b) 2-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl-amino]-ethanol 1:1 Fumarate [0160] Following the general method described in example 9, N-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-5-methyl-pyridin-4-yl]-oxalamic acid ethyl ester (example 11a) was reacted with lithium aluminum hydride. After workup and chromatography the free base of the title compound was treated with an aliquot of fumaric acid and crystallized as the white salt. Mp. 232-233° C. (MeOH/Et 2 O), MS: m/e=284 (M+H + ). EXAMPLE 12 [0161] [2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-methyl-amine 1:1 Fumarate [0162] a) [2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-carbamic Acid Ethyl Ester 1:1 Hydrochloride [0163] In analogy to the general method described in example 8, the title compound was obtained by reaction of 2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amine (example 1) with ethyl chloroformate followed by crystallization of the white hydrochloride salt. Mp. >213° C. (dec) (MeOH/Et 2 O), MS: m/e=298 (M+H + ). [0164] b) [2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-methyl-amine 1:1 Fumarate [0165] Following the general method described in example 9, [2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-carbamic acid ethyl ester (example 12a) was reacted with lithium aluminum hydride. After workup and chromatography the free base of the title compound was treated with an aliquot of fumaric acid to yield a white crystalline material. Mp. 171-172° C. (MeOH/Et 2 O), MS: m/e=239 (M + ). EXAMPLE 13 [0166] [2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-dimethyl-amine 1:1 Fumarate [0167] A solution of 2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-y-lamine (example 1) (2.3 g, 10.0 mmol) in formic acid (16 ml) was treated with aqueous formaldehyde solution (8 ml of a 40% solution). The mixture was refluxed for 1 hr followed by evaporation of the volatiles. The residue was partitioned (AcOEt/NaHCO 3 -solution) and the organic phase was separated, dried (Na 2 SO 4 ) and concentrated. After chromatography (SiO 2 with CH 2 Cl 2 /CH 3 OH/NH 4 OH=300/10/1) the free base of the title compound was obtained as a colorless oil (1.44 g, 57%). It was crystallized as the white fumarate salt. Mp. 177-178° C. (MeOH/Et 2 O), MS: m/e=254 (M+H + ). EXAMPLE 14 [0168] 5-(3,4-Dihydro-1H-isoquinolin-2-yl)-1-methyl-1,4-dihydro-2H-pyrido[4,3-d][1,3]oxazine 1:1 Hydrochloride [0169] The free base of the title compound was obtained as a minor (less polar) product (0.54 g, 19%) in the synthesis of [2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-dimethyl-amine (example 13). It was crystallized as the white hydrochloride salt. Mp. 220-221° C. (MeOH/Et 2 O), MS: ml/e=282 (M+H + ). EXAMPLE 15 [0170] N-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-acetamide 1:1 Hydrochloride [0171] In analogy to the general method described in example 8, the title compound was obtained by reaction of 2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-ylamine (example 1) with acetyl chloride followed by crystallization of the white hydrochloride salt. Mp. 229-230° C. (MeOH/Et 2 O), MS: m/e=267 (M + ). EXAMPLE 16 [0172] [2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-ethyl-amine 1:1 Fumarate [0173] Following the general method described in example 9, N-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-acetamide (example 15) was reacted with lithium aluminum hydride. After workup and chromatography the free base of the title compound was treated with an aliquot of fumaric acid and crystallized as the white salt. Mp. 73-74° C. (MeOH/Et 2 O), MS: ml/e=254 (M + ). EXAMPLE 17 [0174] Benzyl-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-amine [0175] a) N-[2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-benzamide [0176] In analogy to the general method described in example 8, the title compound was obtained by reaction of 2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl-amine (example 1) with benzoyl chloride followed by crystallization of the free base. Mp. 139-140° C. (AcOEt/iPr 2 O), MS: m/e=330 (M+H + ). [0177] b) Benzyl-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-amine [0178] Following the general method described in example 9, N-[2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-benzamide (example 17a) was reacted with lithium aluminum hydride. After workup and chromatography the free base of the title compound was treated with hydrogen chloride and triturated with Et 2 O/pentane. The title compound was obtained as white amorphous material. MS: m/e=315 (M + ). EXAMPLE 18 [0179] 6-(3,4-Dihydro-1H-isoquinolin-2-yl)-4-methyl-pyridin-2-yl-amine 1:1 Hydrochloride [0180] Following the general method described in example 1, the title compound was obtained as a white crystalline material by reaction of 6-bromo-4-methyl-pyridin-2-yl-amine (F. Johnson et al., J. Org. Chem., 1962, 27, 2473) with 1,2,3,4-tetrahydro-isoquinoline and crystallization of the free base as the hydrochloride salt. Mp. 196-197° C. (MeOH/Et 2 O), MS: m/e=240 (M+H + ). EXAMPLE 19 [0181] 6-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl-amine 1:1 Hydrochloride [0182] Following the general method described in example 1, the title compound was obtained as a light brown crystalline material by reaction of 6-bromo-pyridin-2-yl-amine with 1,2,3,4-tetrahydro-isoquinoline and crystallization of the free base as the hydrochloride salt. Mp. 177-178° C. (MeOH/Et 2 O), MS: m/e=225 (M + ). EXAMPLE 20 [0183] 2-(4-Methyl-pyridin-2-yl)-1,2,3,4-tetrahydro-isoquinoline 1:1 Hydrochloride [0184] Following the general method described in example 1, the title compound was obtained as a white crystalline material by reaction of 2-bromo-4-methyl-pyridine with 1,2,3,4-tetrahydro-isoquinoline and crystallization of the free base as the hydrochloride salt. Mp. 142-143° C. (MeOH/Et 2 O), MS: m/e=: 224 (M + ). EXAMPLE 21 [0185] 2-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-3-yl-amine 1:1 Hydrochoride [0186] a) 2-(3-Nitro-pyridin-2-yl)-1,2,3,4-tetrahydro-isoquinoline [0187] A suspension of 2-chloro-5-nitro-pyridine (1.58 g, 10 mmol) in isopropanol (30 ml) was treated at rt with 1,2,3,4-tetrahydro-isoquinoline (2.6 g, 20 mmol). The resulting mixture was stirred for 3 hr. The precipitate was filtered, partitioned (AcOEt/H 2 O) and the organic phase dried (Na 2 SO 4 ). After evaporation of the solvent the title compound was obtained as a yellow solid mass (1.4 g, 55%), MS: m/e=256 (M+H + ). [0188] b)-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-3-yl-amine 1:1 Hydrochoride [0189] To a solution of 2-(3-nitro-pyridin-2-yl)-1,2,3,4-tetrahydro-isoquinoline (example 21a) (1.4 g, 5.5 mmol) in methanol (50 ml) palladium on carbon (10%, 140 mg) was added and the resulting mixture was hydrogenated for 24 hr. After filtration of the catalyst, the reaction mixture was concentrated and chromatographed (SiO 2 with hexane/AcOEt=4/1) to yield the free base of the title compound (0.64 g, 52%) as a brown oil. Treatment with hydrogen chloride gave white crystals. Mp. 195-196° C. (MeOH/Et 2 O), MS: m/e=225 (M 1 ). EXAMPLE 22 [0190] C-[6-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl]-methylamine hydrochloride (1:2) [0191] a) 6-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridine-2-carboxylic acid amide [0192] Following the general method described in example 1, the title compound was obtained as a light yellow crystalline material by reaction of 6-chloro-pyridine-2-carboxylic acid amide with 1,2,3,4-tetrahydro-isoquinoline and crystallization of the free base. Mp. 145-150° C. (AcOEt/hexane), MS: m/e=253 (M + ). [0193] b) C-[6-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl]-methylamine hydrochloride (1:2) [0194] Following the general method described in example 9, 6-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridine-2-carboxylic acid amide (example 22a) was reacted with lithium aluminum hydride. After workup and chromatography the free base of the title compound was treated with hydrogen chloride and crystallized as the off white salt. Mp. 192-195° C. (iPr 2 O), MS: m/e=239 (M + ). EXAMPLE 23 [0195] 5-(3,4-Dihydro-1H-isoquinolin-2-yl)-1-ethyl-1,4-dihydro-2H-pyrido[4,3-d][1,3]oxazine 1:1 Hydrochloride [0196] A solution of [2-(3,4-dihydro-1H-isoquinolin-2-yl)-pyridin-4-yl]-ethyl-amine (example 16) (0.8 g, 3.1 mmol) in formic acid (16 ml) was treated with aqueous formaldehyde solution (8 ml of a 40% solution). The mixture was refluxed for 1 hr followed by evaporation of the volatiles. The residue was partitioned (AcOEt/NaHCO 3 -solution) and the organic phase was separated, dried (Na 2 SO 4 ) and concentrated. After chromatography (SiO 2 with CH 2 Cl/CH 3 OH/NH 4 OH=400/10/1) the free base of the title compound was obtained as a colorless oil (0.74 g, 81%). It was crystallized as the white hydrochloride salt. Mp. 197-198° C. (MeOH/Et 2 O), MS: m/e=295 (M + ). EXAMPLE 24 [0197] 2-Pyridin-4-yl-1,2,3,4-tetrahydro-isoquinoline [0198] A mixture of 4-chloro-pyridine 1:1 hydrochloride (24.5 g, 163 mmol) and 1,2,3,4-tetrahydro-isoquinoline (65.3 g, 490 mmol) was slowly heated to 150° C. After 30 min the reaction mixture was cooled to rt, H 2 O (700 ml) and 2N NaOH (82 ml) was added followed by extraction with AcOEt (5 times 300 ml). The combined organic phases were dried (Na 2 SO 4 ), and the solvent was evaporated. After trituration with pentane and recrystallization the title compound (30.2 g, 88%) was obtained as a light brown crystalline material. Mp. 95-96° C. (AcOEt), MS: m/e=210 (M + ). EXAMPLE 25 [0199] 5-Chloro-2-pyridin-4-yl-1,2,3,4-tetrahydro-isoquinoline 1:1 Hydrochloride [0200] A mixture of 4-bromo-pyridine 1:1 Hydrochloride (0.95 g, 4.9 mmol), 5-chloro-1,2,3,4-tetrahydro-isoquinoline (C. Kaiser et al., J. Med. Chem., 1980, 23, 506) (0.99 g, 4.9 mmol) and Na 2 CO 3 (1.8 g, 17 mmol) in N-methyl-pyrrolidinone (15 ml) was stirred at 170° C. for 3.5 hr. All volatiles were evaporated (at 50° C., 0.01 mbar) and the residue was partitioned (AcOEt/H 2 O). The organic phase was dried (Na 2 SO 4 ), concentrated and chromatographed (SiO 2 with CH 2 Cl 2 /CH 3 OH/NH 4 OH=250/10/1). The free base of the title compound was obtained as a light brown crystalline material (0.71 g, 59%). It was crystallized as the white hydrochloride salt. Mp. 258-259° C. (MeOH/Et 2 O), MS: m/e=244 (M + ). EXAMPLE 26 [0201] 8-Chloro-2-pyridin-4-yl-1,2,3,4-tetrahydro-isoquinoline 1:1 Fumarate [0202] Following the general method described in example 25, the free base of the title compound was obtained by reaction of 4-bromo-pyridine 1:1 Hydrochloride with 8-chloro-1,2,3,4-tetrahydro-isoquinoline (C. Kaiser et al., J. Med. Chem., 1980, 23, 506) and Na 2 CO 3 in N-methyl-pyrrolidinone. It was crystallized as the light yellow fumarate salt. Mp. 178-179° C. (MeOH), MS: m/e=244 (M + ). EXAMPLE 27 [0203] 6-Chloro-2-pyridin-4-yl-1,2,3,4-tetrahydro-isoquinoline 1:1 Hydrochlorid [0204] Following the general method described in example 25, the free base of the title compound was obtained by reaction of 4-bromo-pyridine 1:1 hydrochloride with 6-chloro-1,2,3,4-tetrahydro-isoquinoline (C. Kaiser et al., J. Med. Chem., 1980, 23, 506) and Na 2 CO 3 in N-methyl-pyrrolidinone. It was crystallized as the light brown hydrochloride salt. Mp. >250° C. (MeOH/Et 2 O), MS: m/e=245 (M+H + ). EXAMPLE 28 [0205] 7-Chloro-2-pyridin-4-yl-1,2,3,4-tetrahydro-isoquinoline [0206] In analogy to the general method described in example 25, the title compound was obtained as a white crystalline material by reaction of 4-chloro-pyridine 1:1 hydrochloride with 7-chloro-1,2,3,4-tetrahydro-isoquinoline (C. Kaiser et al., J. Med. Chem., 1980, 23, 506) and Cs 2 CO 3 in DMF. Mp. 100-101° C. (AcOEt/pentane), MS: m/e=244 (M + ). EXAMPLE 29 [0207] rac.-4-Methyl-2-pyridin-4-yl-1,2,3,4-tetrahydro-isoquinoline 1:1 Hydrochloride [0208] Following the general method described in example 25, the free base of the title compound was obtained by reaction of 4-bromo-pyridine 1:1 hydrochloride with rac.-1-methyl-1,2,3,4-tetrahydro-isoquinoline (G. Grunewald et al., J. Med. Chem., 1988, 31, 433) and Na 2 CO 3 in N-methyl-pyrrolidinone. It was crystallized as the off-white hydrochloride salt. Mp. 224-227° C. (MeOH/Et 2 O), MS: m/e=224 (M + ). EXAMPLE 30 [0209] 4-(3,4-Dihydro-1H-isoquinolin-2-yl)-pyridin-2-yl-amine [0210] Following the general method described in example 24, 4-bromo-pyridin-2-yl-amine (H. J. den Hertog, Recl. Trav. Chim. Pays-Bas, 1945, 64, 85) was reacted with 1,2,3,4-tetrahydro-isoquinoline. The crude product was chromatographed (SiO 2 with CH 2 Cl 2 /CH 3 OH/NH 4 OH=200/10/1) and crystallized to yield the title compound as an off-white crystalline material. Mp. 160-161° C. (CH 3 CN), MS: m/e=226 (M+H + ). EXAMPLE 31 [0211] 2-(2-Methyl-pyridin-4-yl)-1,2,3,4-tetrahydro-isoquinoline 1:1 Fumarate [0212] Following the general method described in example 24, 4-bromo-2-methyl-pyridine (S. Ochiai, Pharm. Bull., 1954, 2, 147) was reacted with 1,2,3,4-tetrahydro-isoquinoline. The crude product was chromatographed (SiO 2 with CH 2 Cl 2 /CH 3 OH/NH 4 OH 200/10/1) and crystallized as the white fumarate salt. Mp. 155-156° C. (MeOH/Et 2 O), MS: m/e=225 (M+H + ). EXAMPLE 32 [0213] 4-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl-amine 1:1 Fumarate [0214] a) 4-Bromo-6-methyl-pyridin-2-yl-amine [0215] A mixture of 2,4-dibromo-6-methyl-pyridine (J. Bernstein et al., J. Amer. Chem. Soc., 1947, 69, 1147) (22.6 g, 90 mmol) and aqueous ammonia (25%, 260 ml) was stirred in an autoclave at 160° C. for 4 hr. The reaction mixture was cooled to rt and extracted with Et 2 O. The organic phase was dried (Na 2 SO 4 ), concentrated and chromatographed (SiO 2 with AcOEt/hexane/NEt 3 =10/30/1) to yield the title compound as a white crystalline material (4.0 g, 6%). NMR (250 MHz, DMSO): δ=3.33 (s, 3H, CH 3 ), 6.13 (s, broad, 2H, NH 2 ), 6.44 (s, 1H, arom-H), 6.54 (s, 1H, arom-H). [0216] b) 4-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl-amine 1:1 Fumarate [0217] Following the general method described in example 24, 4-bromo-6-methyl-pyridin-2-yl-amine (example 32a) was reacted with 1,2,3,4-tetrahydro-isoquinoline. The crude product was chromatographed (SiO 2 with CH 2 Cl 2 /CH 30 H/NH 4 OH=200/10/1) and crystallized as the white fumarate salt. Mp. >270° C. (MeOH), MS: m/e=240 (M+H + ). EXAMPLE 33 [0218] N-[4-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl]-oxalamic acid ethyl ester 1:1 Hydrochloride [0219] Following the general method described in example 8, the title compound was obtained as a light yellow crystalline material by reaction of 4-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl-amine (example 32) with ethyl chlorooxoacetate followed by crystallization of the hydrochloride salt. Mp. >160° C. (dec.)(EtOH/Et 2 O), MS: m/e=340 (M+H + ). EXAMPLE 34 [0220] N-[4-(3,4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl]-2-hydroxy-acetamide [0221] A solution of N-[4-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl]-oxalamic acid ethyl ester (example 33) (0.43 g, 1.3 mmol) in THF (20 ml) was cooled in an ice bath and lithium aluminum hydride (0.12 g, 3.2 mmol) was added in. The mixture was stirred at rt for 2 hr, quenched with saturated aqueous Seignette-salt solution and filtered. The organic phase was dried (Na 2 SO 4 ) and concentrated. After chromatograpy (SiO 2 with CH 2 Cl/CH 3 OH/NH 4 OH=200/10/1) the title compound was obtained as a colorless oil (0.18 g, 47%). Mp. 160-162° C. (AcOEt), MS: m/e=296(M−H − ). EXAMPLE 35 [0222] [4-Dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl-amino]-ethanol 1:1 Fumarate [0223] Following the general method described in example 9, N-[4-(3,4-dihydro-1H-isoquinolin-2-yl)-6-methyl-pyridin-2-yl]-oxalamic acid ethyl ester (example 33) was reacted with lithium aluminum hydride. After workup and chromatography the free base of the title compound was treated with an aliquot of fumaric acid and crystallized as the white salt. Mp. 160° C. (MeOH), MS: m/e=284 (M+H + ). EXAMPLE A [0224] [0224] Tablet Formulation (Wet Granulation) mg/tablet Item Ingredients 5 mg 25 mg 100 mg 500 mg 1. Active Ingredient*  5  25 100 500 2. Lactose Anhydrous DTG 125 105  30 150 3. Sta-Rx 1500  6  6  6  30 4. Microcrystalline Cellulose  30  30  30 150 5. Magnesium Stearate  1  1  1  1 Total 167 167 167 831 [0225] Manufacturing Procedure [0226] 1 Mix items 1, 2, 3 and 4 and granulate with purified water. [0227] 2. Dry the granulation at 50° C. [0228] 3. Pass the granulation through suitable milling equipment. [0229] 4. Add item 5 and mix for three minutes; compress on a suitable press. EXAMPLE B [0230] [0230] Capsule Formulation mg/capsule Item Ingredients 5 mg 25 mg 100 mg 500 mg 1. Active Ingredient  5  25 100 500 2. Hydrous Lactose 159 123 148 — 3. Corn Starch  25  35  40  70 4. Talc  10  15  10  25 5. Magnesium Stearate  1  2  2  5 Total 200 200 300 600 [0231] Manufacturing Procedure [0232] 1 Mix items 1, 2, and 3 in a suitable mixer for 30 minutes. [0233] 2. Add items 4 and 5 and mix for 3 minutes. [0234] 3. Fill into a suitable capsule. [0235] 4. Add item 5 and mix for three minutes; compress on a suitable press.

The invention relates to compounds of formulae Compounds of the invention have a good affinity to the NMDA receptor and are useful for the treatment of diseases related to this receptor.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is related to commonly owned U.S. Pat. No. 3,889,054, issued June 10, 1975, and is an improvement on the row grabbing system described therein; and is related to the following commonly owned copending U.S. patent applications: "Information Retrieval System Having Selectable Purpose Variable Function Terminal", filed Sept. 10, 1975, and bearing U.S. Ser. No. 611,927, by Robert H. Nagel; "Row Grabbing Video Display Terminal Having Local Programmable Control Thereof", filed Apr. 23, 1976, and bearing U.S. Ser. No. 679,558, by Lenard Wintfeld and Robert H. Nagel; "Improved Row Grabbing System", filed Sept. 10, 1975, and bearing U.S. Ser. No. 611,843, by Robert H. Nagel and Richard Saylor; "Interface for Enabling Continuous High Speed Row Grabbing Video Display With Real Time Hard Copy Print Out Thereof", filed Apr. 23, 1976, and bearing U.S. Ser. No. 679,907, by Richard Saylor; "Digital Video Signal Processor With Distortion Correction", filed Apr. 23, 1976, and bearing U.S. Ser. No. 679,909, by Richard Saylor; "Phase Locked Loop For Providing Continuous Clock Phase Correction", filed Apr. 23, 1976, and bearing U.S. Ser. No. 679,701, by Richard Saylor; and "Piggy Back Row Grabbing System", filed June 23, 1976, and bearing U.S. Ser. No. 699,088, by Richard Saylor; the contents of all of which are hereby specifically incorporated by reference herein. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to video communication systems in which individual frames may be grabbed for video display thereof. 2. Description of the Prior Art Video communication systems in which the individual frames may be grabbed for video display are well known, such as the system disclosed in U.S. Pat. No. 3,740,465, or a system employing the Hitachi frame grabbing disc. These prior art systems such as the one disclosed in U.S. Pat. No. 3,746,780 are normally two-way request response systems requiring the user to request information by the dialing of a specific digital code which is uniquely assigned to each frame. However, such systems normally grab a group of frames for storage and then subsequently select the individual frame for display out of the group of grabbed frames as opposed to instantaneously selecting a single frame in real time. Furthermore, such prior art systems do not provide for real time updating of the grabbed video frame. In addition, some such prior art frame grabbing systems, such as the type disclosed in U.S. Pat. No. 3,397,283, are normally capable of only grabbing the next immediate signal in response to the provision of a starter signal or, as disclosed in U.S. Pat. No. 3,051,777, utilize a counter or frame location which must be reset to the beginning of a tape for video tape supplied information in order to locate a selected frame to be grabbed. These systems are not applicable in a real time frame grabbing environment. Similarly, other typical prior art frame grabbing systems, such as disclosed in U.S. Pat. Nos. 3,695,565; 2,955,197; 3,509,274; 3,511,929 and 3,582,651, cannot be utilized in a real time frame grabbing environment, such as one in which the video information associated with the grabbed frame is capable of being continuously updated. Accordingly, presently available prior art frame grabbing systems familiar to the Inventors, other than commonly owned U.S. Pat. No. 3,889,054, are not capable of easily locating a frame to be grabbed in real time nor of being able to continuously update such a grabbed frame in real time. Video communication systems in which the signal being transmitted is digitized are also well known. For example, U.S. Pat. No. 3,743,767 discloses a video communication system for the transmission of digital data over standard television channels wherein the digital data is transmitted in a conventional television scan line format through conventional television distribution equipment. However, such a prior art communication system merely digitizes one television scan line at a time for distribution to a video display terminal on a bit-by-bit basis in a line, 84 bits of information being provided per television scan line. Furthermore, such a prior art system is not transmission selectable by every display terminal nor is the data for a displayable video row packed into a self-contained pseudo video scan line information packet. Thus, there is no significant increase in the data transmission rate resulting from such a prior art video communication system. Similarly, U.S. Pat. Nos. 3,061,672 and 3,569,617 and German Pat. No. 2,307,414 are examples of other prior art video communication systems in which television signals are digitized without any significant resultant compression in data transmission time. Furthermore, these other prior art systems require special distribution circuitry. In addition, prior art video communication systems in which a digital television signal is transmitted do not sufficiently isolate the individual rows comprising a frame so as to provide satisfactory noise immunity between these rows nor is there satisfactory data compression in the transmission time of the video information in such prior art systems nor satisfactory distortion compensation. Furthermore, although the row grabbing system described in our previously mentioned U.S. Pat. No. 3,889,054, issued June 10, 1975 overcomes several of the aforementioned disadvantages of the prior art, it would be desirable if the already high speed transmission rate of this row grabbing system could be further increased and furthermore, if the system reliability of such a row grabbing system which was continuously utilized for the continuous transmission of real-time information could be further enhanced. These disadvantages of the prior art are overcome by the present invention. SUMMARY OF THE INVENTION A real time frame grabbing system for substantially instantaneously providing a continuous video display of a selectable predetermined video frame of information on a video display means from continuously transmittable video information comprises at least a first means for transmitting the video information as a first plurality of pseudo video scan lines, second means for transmitting the video information as a second plurality of pseudo video scan lines and means for selectively combining and interleaving corresponding identical out of phase digital information content containing pseudo video scan line portions of the first and second plurality of pseudo video scan lines to provide an in phase composite combined interleaved pseudo video scan line to the video display means. Each of the pseudo video scan lines from the first and second transmitting means has a television video scan line format and is capable of comprising a complete self-contained packet of digital information sufficient to provide an entire displayable row of video data characters. This displayable row comprises a plurality of television video scan lines. The pseudo video scan line has an associated transmission time equivalent to that of the television video scan line with the packet of digital information contained therein comprising at least address information for the displayable row and data information for the displayable characters in the displayable row. The first transmitting means transmits the first plurality of pseudo video scan lines out of phase in time in a predetermined phase relationship, such as 180° out of phase in the instance of two transmitting means, with the transmission of the second plurality of pseudo video scan lines by the second transmitting means with, however, the digital information content of the first and second plurality of pseudo video scan lines being substantially indentical. The composite combined interleaved pseudo video scan line provided from the combining and interleaving means also has a television video scan line format and is capable of comprising a complete self-contained composite packet of digital information equivalent in content to the content of either of the interleaved pseudo video scan lines and sufficient to provide the entire displayable row of video data characters to the video display means. The combined interleaved composite pseudo video scan line also preferably has an associated transmission time equivalent to that of a television video scan line. The interleaved information containing portion of the corresponding pseudo video scan line of the first plurality of pseudo video scan lines preferably comprises different television video scan lines, such as odd numbered television scan lines, of the plurality of television video scan lines which comprise the composite pseudo video scan line displayable row than the interleaved portions of the corresponding pseudo video scan lines of the second plurality of pseudo video scan lines which, in the above instance, would then occupy even numbered television video scan lines. The combining and interleaving means also preferably comprises means for providing a video black signal for each of the television video scan lines of the plurality comprising the composite displayable row for which a corresponding pseudo video scan line portion is not transmitted, in which instance, the combining and interleaving means provides the composite combined interleaved pseudo video scan line from the corresponding pseudo video scan line portion transmitted from the transmitting means and the video black signals in the absence of the transmission of corresponding pseudo video scan line portions from the second transmitting means, and vice versa. The combining and interleaving means also preferably includes means for providing a composite video signal as the composite combined interleaved pseudo video scan line, including means for providing a horizontal sync signal at the beginning of each of the composite combined interleaved pseudo video scan lines which provides a record separator between adjacent composite combined interleaved pseudo video scan lines, the combining and interleaving means further providing a vertical sync signal after a predetermined plurality of composite combined interleaved pseudo video scan lines have been provided therefrom. In addition, the combining and interleaving means further comprises means for providing at least one empty line, and preferably three such empty lines, to the video display means after vertical blanking but prior to data line transmission of a plurality of composite combined interleaved pseudo video scan lines which comprise the video frame and means for inserting a start bit pulse in the empty lines for enabling phase lock by the video display means prior to the reception of data at the start of the vertical video frame. The system further comprises television signal distribution means for distributing the provided composite combined interleaved pseudo video scan line signals to the video display means for providing the continuous video display as well as receiver means operatively connected between the television signal distribution means and the video display means for processing the distributed composite combined interleaved pseudo video scan line signals and capable of providing a displayable video row signal to the video display means from each of the composite combined interleaved pseudo video scan line signals pertaining to the selected frame for providing the continuous video display. A predetermined plurality of displayable video rows comprises the displayable video frame of information. The aforementioned receiver means preferably comprises means for updating the continuously video displayable selectable frame on a displayable video row-by-row basis dependent on the real time data information content of the received composite combined interleaved pseudo video scan lines. Each of the packets of digital information comprised in the composite combined interleaved pseudo video scan lines further comprise an error check information content based on the data information content for the displayable characters of an associated composite combined interleaved pseudo video scan line. The receiver signal processing means comprises error check means for obtaining an error check indication from the distributed associated composite combined interleaved pseudo video scan line and comparing the error check indication with the error check information content of the associated composite combined interleaved pseudo video scan line in accordance with a predetermined error check condition for providing a predetermined output condition signal when the error check condition is satisfied. The receiver signal processing means further comprises condition responsive means operatively connected to the error check means to receive the predetermined output condition signal therefrom when provided. This condition responsive means inhibits the provision of the displayable video row from the associated composite combined interleaved pseudo video scan line signal when the predetermined output condition signal is not provided thereto. The television signal distribution means preferably comprises means for compensating for television transmission distortion in the provided composite combined interleaved pseudo video scan lines provided to the video display means. This distortion compensation means comprises means for limiting the associated energy distribution of the waveform comprising the provided composite combined interleaved pseudo video scan line signal to bring this energy distribution within restrictions associated with the television signal distribution means, such as with a cable TV system if that is the means of television signal distribution utilized. This limiting means preferably comprises a sin 2 filter means for introducing a controllable distortion in the provided composite combined interleaved pseudo video scan line signal which thereby provides the energy distribution limitations. The distribution of the controllably distorted signal through the television signal distribution means provides the composite combined interleaved pseudo video scan line signal to the receiver means substantially free of such television transmission distortion. The distortion compensation means also preferably comprises means operatively connected to the filter means for compensating for television transmission distortions introduced by envelope detection of vestigal sideband television demodulation by providing an additional controllable distortion in the controllably distorted provided signal from the filter means. The distribution of this additionally controllably distorted signal through the television signal distribution means provides the composite combined interleaved pseudo video scan line signal to the receiver means substantially free of such vestigal sideband demodulation distortion. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a system block diagram of the preferred embodiment of the row grabbing system of the present invention; FIG. 2 is a more detailed block diagram of a typical transmitter means portion of the system of FIG. 1; FIG. 3 is a more detailed block diagram of the master combiner synchronizer portion of the system of FIG. 1; FIGS. 4 and 5 taken together comprise a logic schematic diagram of the master combiner synchronizer portion of FIG. 3; FIGS. 6 through 8 taken together comprise a logic schematic diagram of the typical transmitter portion of FIG. 2; FIG. 9 is a schematic diagram of the output network of FIG. 1; FIG. 10 is an illustrative timing diagram of the various waveforms present in the cable head portion of the system of FIG. 1; FIGS. 11A through 11E comprise a timing diagram of graphic illustrations of the various waveforms and their associated energy distributions present in the output network of FIG. 9; FIG. 12 comprises a timing diagram graphic illustration of the various waveforms present in the cable head portion of the system of FIG. 1; and FIG. 13 is a diagrammatic illustration of the preferred pseudo video scan line provided by the cable head portion of the system of FIG. 1. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS "General System Description" The improved row grabbing system of the present invention, generally referred to by the reference numeral 10, is shown in block in FIG. 1 which includes a block diagram of the preferred improved cable head, generally referred to by the reference numeral 13, of the present invention. The cable head 13 is the system for providing the pseudo video scan lines of the type described in commonly owned copending U.S. patent application Ser. No. 611,843, filed Sept. 10, 1975 and entitled "Improved Row Grabbing System", the contents of which are specifically incorporated by reference herein, this system being a further improvement on the system described in the aforementioned copending patent application. With respect to FIG. 1 of the present invention, this figure corresponds to an improvement on what is shown in FIG. 19 of the aforementioned copending patent application and identical reference numerals are used herein for identically functioning components with the same reference numerals followed by the letters a and b, respectively, if there is a plurality of such similarly functioning elements. As shown and preferred in FIG. 1, the improve preferred cable head 13 preferably includes a pair of computers 2000 a and 2000b, each having an associated mass memory 2010a and 2010b, respectively, which are preferably identical in function and operation to computer 2000 and associated mass memory 2010 as previously described in the aforementioned copending U.S. patent application with the exception that information provided from computer 2000a and 2000b is preferably identical in content but 180° out of phase in terms of time relationship to the provision of this information, as will be described in greater detail hereinafter. Of course, as will be apparent to one of ordinary skill in the art, the resultant 180° phase differential may be accomplished in other manners. The information output of computer 2000a is preferably provided to an improved preferred transmitter portion 8202a and the information output of computer 2000b is preferably similarly provided to an improved preferred transmitter portion 8202b. Preferably transmitter portions 8202a and 8202b are identical in function and operation and one such typical transmitter portion 8202a shall be described in greater detail hereinafter with reference to FIGS. 1, 3, 6, 7 and 8. The transmitter portions 8202a and 8202b preferably provide both serial data information and status and control information to a preferred master combiner and synchronizer portion 8204, with the status and control information being bidirectional, that is transmitted to and from master combiner and synchronizer portion 8204, whereas the serial data information is unidirectional only, that is only transmitted to master combiner and synchronizer portion 8204, both being provided from the respective transmitter portion 8202a or 8202b to the common master combiner and synchronizer portion 8204 in the presently preferred embodiment of the present invention. As will be described in greater detail hereinafter, with reference to FIGS. 4 and 5, the master combiner and synchronizer portion 8204 preferably combines the pseudo video scan line information transmitted from each of the computers 2000a and 2000b to generate a single pseudo video scan line output. This is preferably accomplished by the master combiner and synchronizer portion 8204, as will be described in greater detail hereinafter with reference to FIGS. 4 and 5, by the master combiner and synchronizer portion 8204 preferably placing packets of digital information comprising a pseudo video scan line from one computer, for example computer 2000a, on odd television scan lines while placing packets of digital information comprising a pseudo video scan line provided from the other computer, such as computer 2000b by way of example, on even television scan lines, both the odd and even television scan lines being combined to comprise the single composite psuedo video scan line output of master combiner and synchronizer portion 8204. If either or both computers 2000a and 2000b stop sending packets of such digital information, in the interleaved mode, their respective associated or assigned scan lines in the output of portion 8204 preferably remain video "black". Furthermore, if desired, in the preferred system 10 of the present invention, either the odd or even transmission of such information, from either computer 2000a or 2000b, respectively, can be turned off and the system can operate with a single computer, 2000a or 2000b in the manner described in the aforementioned copending patent application is such interleaved transmission is not desired or if one of the computers 2000a or 2000b becomes inoperable, in which instance, as will be described in greater detail hereinafter, the retrieval or access rate of the information becomes halved as compared to the rate associated with the interleaved transmission. As will further be described in greater detail hereinafter, consequently, by utilizing the preferred interleaved transmission provided from the two computers 2000a and 2000b which provide identical information preferably 180° out of phase, the access time for this information is preferably half the access time obtained from the system described in the aforementioned copending U.S. patent application when only one such computer is utilized. As further shown and preferred in FIG. 1, the improved cable head 13 also preferably includes an output network 8206. The output network receives the output from the master combiner and synchronizer portion 8204, which is preferably a composite video signal and a separate color burst signal, the composite video signal preferably being a composite black and white type of video signal. Output network 8206 preferably includes a pre-equalization filter 8207 which preferably compensates for signal distortion in the composite video signal output of the master combiner and synchronizer 8204 as will be described in greater detail hereinafter with reference to FIGS. 9 and 11A through 11E. Ther output network 8206 also preferably includes a conventional video line driver 8208 which is connected to the output of a conventional summing network 8209 which sums the color burst signal with the distortion compensated composite video signal output of pre-equalization filter 8207 to preferably provide a composite color type of television signal; that is a pseudo video scan line which has the characteristics of a conventional color television scan line, in that it has color burst, with the exception that no color subcarrier is provided in the composite color pseudo video scan line output 12a of network 8206. This output signal 12a is preferably the same type of signal as illustrated in FIG. 2 of the aforementioned copending U.S. patent application and which diagram is repeated herein as FIG. 13 for purposes of clarity. As shown and preferred in FIG. 13, this pseudo video scan line 12a, as was previously described, is identical in format to a conventional video scan line; that is, it is consistent with FCC and EIA standards for video scan line signal format; however this pseudo video scan line 12a actually contains a row of information, such as approximately between 11 and 13 actual television video scan lines of information with the transmission time of the pseudo video scan line 12a being equal to the transmission time of a conventional TV video scan line, which is approximately 63 microseconds. With respect to the pseudo video scan line 12a, the horizontal sync and vertical sync portions are preferably identical to a conventional video signal as is the format for the horizontal sync and the vertical sync as well as the horizontal sync amplitude. The time and ampliude envelope of the video region of the pseudo video scan line 12a, which region is defined as areas H, J, B, C, D, E and K in FIG. 13, is identical with the format for a conventional video scan line as is the three dimensional frequency envelope. Thus, all of the above mentioned standard conditions for a conventional video scan line signal are met by the pseudo video scan line 12a provided at the output of network 8206. Accordingly, any equipment that can handle conventional video can handle the pseudo video scan line output 12a signal which can thus be transmitted and received through a conventional television distribution system with conventional television equipment. Returning once again to the pseuo video scan line 12a illustrated in FIG. 3, as is also true for the pseudo video scan line of the type previously described in U.S. Pat. No. 3,889,054, this signal is in reality a digital signal which looks like conventional video scan line to the receiver 28a or 28b. Pseudo video scan line 12a, as will be described in greater detail hereinafter, however, preferably employs a start bit to provide timing and phase adjustment for the phase locked loop of the receiver terminal 28a or 28b s described in the aforementioned copending patent application. In such an instance, region F which was previously contained in the pseudo video scan line transmitted in the system of U.S. Pat. No. 3,889,054, and which contained the clock synchronizing burst or pulse train at the bit rate (the frequency preferably being equal to one-half the bit rate) and comprised a pulse train of ones and zeros for two character spaces or 14 bits, is not present and the sync burst information which was previously contained therein is not required for timing and phase adjustment. Instead, region H, which preferably contains color burst information and region J which preferably contains one start bit, are preferably inserted between regions A and B, with regions B, C, D and E being electronically shifted down in position to be adjacent region G, only being separated therefrom by a region K, which region K merely represents the standard TV spacing for providing the front porch of the signal, the back porch of the signal being defined between region A and the leading edge of the start bit in region J. The color burst signal in region H preferably is the standard FCC eight cycle signal at 3.58 megahertz. Apart from the repositioning and deletion of certain regions of the pseudo video scan line, the contents of regions A, B, C, D, E and G in pseudo video scan line 12 of FIG. 13 are preferably identical with that previously described with reference to FIG. 1 of U.S. Pat. No. 3,889,054 with respect to the transmission of a displayable row of data. Suffice it to say for purposes of clarity, that region A represents the horizontal sync signal which indicates the beginning of the pseudo video scan line from the beginning of the horizontal sweep for a conventional television scan line; and region B represents the pseudo video scan line 12a address which contains all the following information bit locations, a one preferably indicating the presence of a pulse and a zero preferably indicating the absence of a pulse, all of the following information bits preferably being present when data is transmitted: group, which is the section or chapter including a predetermined number, such as 1,000, of pages and is the most significant bit of the page address, page, which represents one frame in a group, and row which occupies one character space which is preferably 7 bits and defines a portion of the page preferably containing approximately 11 to 13 scan lines which comprise one displayable character. The region B also preferably contains direct address information, which is the first transmitted bit preferably and is a zero unless a direct address condition exists which is a control condition for a selected terminal informing the terminal to supercede the requested page. This region B also preferably contains permission information which is a one bit position which is preferably a one only when the user is being given authority to receive one or more selected groups of information. It should be noted that preferably there is also an emergency override condition which provides control information to all terminals to override all requests including the permission request and preferably occurs on a page and group information bit location of zero, this condition preferably being utilized to display emergency information such as a civil defense warning. Region C is preferably a special character information region of 7 bits which is preferably utilized for optional functions to be performed by the individual receiver 28a to 28b or terminal. Region D preferably contains 32 characters of displayable information in digital form. Region E preferably contains error check information, as will be described in greater detail hereinafter. Region G is preferably the same as region A and represents the horizontal sync signal. As was previously mentioned, the vertical sync is preferably provided by generating a special sequence of horizontal sync pulses during the normal television blanking period, which is after approximately 236 horizontal sync pulses, which as in U.S. Pat. No. 3,889,054 may preferably be after approximately 15 pages have been transmitted. Therefore, 15 pages are transmitted before each vertical sync. The sync signal looks like a conventional composite sync signal with a vertical sync interval comprising approximately nine normal horizontal sync pulse times. The aforementioned combined composite psuedo video scan line signal output of network 8206 is preferably provided to a conventional CATV RF modulator 24, such as the type of modulator described in the aforementioned copending U.S. patent application, one such modulation 24 being preferably provided for each television channel on which formation is to be transmitted, only one such channel being illustrated in FIG. 1 by way of example. Modulator 24, by way of example, preferably provides this information to a conventional CATV cable system 22 such as described in the aforementioned copending U.S. patent application. Referring now to the type of video information provided to the system of FIG. 1, this information is provided from external information sources, two such sources 2002 and 2004, being shown by way of example. The provision of this external information, as is the operation of computers 2000a and 2000b and associated mass memories 2010a and 2010b, is preferably identical with that described in the aforementioned copending U.S. patent application, or in U.S. Pat. No. 3,889,054, with the exceptions thereto to be described in greater detail hereinafter. Thus, the associated mass memories 2010a and 2010b are preferably read in conventional fashion by the associated computers 2000a and 2000b to provide the requisite information via the associated transmitter portions 8202a, 8202b to the master combiner and synchronizer 8204, which information is preferably interleaved as previously generally described, with the associated mass memories 2010a and 2010b each preferably having sufficient storage capacity to store the entire page capacity of the system 10. As will be described in greater detail hereinafter, each of the computers 2000a and 2000b may preferably be, by way of example, either a PDP-8E or PDP-11 manufactured by Digital Equipment Corporation, with respective associated mass memories 2010a and 2010b normally utilized with such computers 2000a and 2000b, respectively. These computers need not both be the same such as, by way of example, utilizing a PDP-8E for computer 2000a and a PDP-11 for computer 2000b. It should be noted that as used throughout the specification and claims, the term "page" means one video frame of information, the term "group" means a predetermined number of pages, the term "row" is a displayble video row and means a portion of a page containing a plurality of conventional television video scan lines, and the term "pseudo video scan line " means a signal which is identical in form to that of a conventional video scan line but which actually contains a row of information, such as approximately between 11 and 13 actual television video scan lines of information with the transmission time of the pseudo video scan line preferably being equal to the transmission time of a conventional TV video scan line, which is approximately 63 microseconds, and with the pseudo video scan line being an entire packet of information necessary for video display of that row. The term conventional or television video scan line or TV scan line is used in its conventional manner. "Typical Transmitter Portion" General Description Referring now to FIG. 2, FIG. 2 is a detailed block diagram of a typical transmitter portion, such as transmitter portion 8202a, of the preferred cable head 13 shown in FIG. 1. As previously alluded to, there are preferably two types of transfers that can take place between the computer 2000a or 2000b and the cable head 13, a status transfer and a data transfer. The status transfer is preferably bidirectional, that is the computer 2000a or 2000b can send status to the cable head 13 and receive status from the cable head 13. A status transfer to the cable head 13 preferably consists of a single word transfer as does a status transfer from the cable head 13. Such a status word is preferably returned from the cable head 13 after every status word received by the cable head 13. The second type of aforementioned transfer that can preferably take place is the unidirectional transfer of data from the computer 2000a or 2000b to the cable head 13. This is accomplished through the data break, that is the direct memory access facility of the computer 2000a or 2000b. Such data transfers must preferably consist of an integral number of data packets per transfer, with each such data packet preferably consisting of 20 words, each word preferably comprising 12 (PDP-8E) or 16 (PDP-11) bits. The principal video data characters are preferably transmitted in six bit sequences. Thus, data is preferably transferred from the computer 2000a or 2000b in a direct memory access transfer. The aforementioned status word transfer from the computer 2000a or 2000b is preferably utilized to insert a seventh bit of data for each transmitted video character. This seventh bit of data is preferably utilized, principally, for special applications of the preferred system of the present invention. An example of such use would be when it is desired to display graphic symbols as well as characters. The status transfer for generation of the seventh bit is preferably used only when the computer 2000a or 2000b is a 12 bit machine such as is the case with the PDP-8E. The PDP-11 is a 16 word machine and when it is used the seventh bit is included as part of the direct memory access transfer word. The status word transfer from the cable head 13 to the computer 2000a or 2000b is preferably used to provide the computer 2000a or 2000b with information pertaining to the mode of operation of the cable head 13. Examples of this kind of information are start of vertical field, odd or even line transmissions, or operator control settings. Referring to FIG. 2, which is a detailed block diagram of typical transmitter portion 8200a, the typical transmitter portion 8202a includes control circuits 8210 which are involved with the direct memory access data transfer. The output line from the computer 2000a or 2000b is asserted whenever data is available. These control circuits 8210 preferably respond thereto by asserting the "acknowledgment" line. When a complete transfer of data has been completed, the computer 2000a or 2000b asserts the "done" line. Portion 8202a also includes control circuits 8211 which control the operation of data transfer during a status word transfer. This is accomplished via the various interrupt lines to the computer 2000a or 2000b. These will be described in greater detail hereinafter. During data transfer the 12 bit data words from the computer 2000a or 2000b are applied to a conventional first in-first out buffer 8212. This buffer 8212 permits words to be stored and then shifted out asynchronously. Buffer 8212 applies the output data words to an output multiplexer 8218 and to a check sum circuit 8217. Depending on the setting of the status word, a status register 8213 may apply a seventh bit to the data stream via a seventh bit addition circuit 8215. During the transmission of a pseudo video scan line, check sum circuit 8217 continously adds digitally the value of one 7 bit word to the sum of the previous words of that same line. This operation preferably continues through 37 video characters. During the 38th and preferably final character of the pseudo video scan line the sum is deposited as the 38th character. Multiplexer 8218 preferably selects the data words for the check sum depending on the associated character numbers. As shown and preferred in FIG. 2, a parallel to serial converter 8219 converts the seven bit data words to a serial data line. This line is fed to the master combiner synchronizer 8204. Other control circuits and counters illustrated in FIG. 2 are used to control the operation and timing of the aforementioned circuits as well as of a status control circuit 8214, word counters 8216 and an output control circuit 8220, all of which will be discussed in greater detail hereinafter. A more detailed description of the function and operation of the various circuits illustrated by the functional blocks 8210, 8211, 8212, 8213, 8214, 8215, 8216, 8217, 8218, 8219 and 8220 in FIG. 2 which comprise the typical preferred transmitter portion 8202a of the preferred cable head 13 will be described in greater hereinafter with reference to FIGS. 7 and 8. "Master Combiner Synchronizer Portion" General Description Referring now to FIG. 3, FIG. 3 is a detailed block diagram of the preferred embodiment of the master combiner synchronizer portion 8204 of the preferred cable head 13 illustrated in FIG. 1. As shown and preferred in FIG. 3, portion 8204 includes a conventional oscillator 8240, which is the single source of all timing signals within the cable head 13. This oscillator 8240 is preferably a crystal controlled 143.1818 meghertz oscillator. The output of this oscillator 8240 is preferably applied to two conventional frequency dividers 8241 and 8242. Divider 8241 preferably divides the oscillator frequency by a factor of 28 to preferably provide a 5.113 megahertz signal which is the clock for the data. This clock preferably establishes the timing of the data bits in the pseudo video TV scan line. The other frequency divider 8242 preferably divides the oscillator frequency by a factor of 10 to provide a 14.318 megahertz signal to a conventional TV sync generator 8243. This sync generator 8243 preferably includes additional conventional frequency dividers and gating circuits as necessary for generating conventional televison synchronizing signals and color reference signals. A television color burst signal is generated on line 8250 at the output of gate 8256. This gate 8256 preferably receives a continous burst subcarrier and a color flag from the sync generator 8243. The color flag is preferably used to gate the color subcarrier to generate the color burst provide via path 8250. Master combiner synchronizer portion 8204 also preferably includes timing control circuit 8244 which utilizes the composite blanking, color flag, and 5.113 megahertz clock to generate character timing signals. One of these signals, the load enable signal is provided via path 8252 to the transmitters 8202a and 8202b to establish the time for loading data words into the parallel-to-serial converter 8219. In addition, timing control circuit 8244 generates post-sync and frame enable signals which are preferably utilized by a line select circuit 8245 to generate a line select control signal via path 8254 which is subsequently preferably utilized by a data select circuit 8246 to select DATA A from transmitter 8202a or DATA B from transmitter 8202b; DATA A and DATA B, as previously mentioned, being identical in content but 180° out of phase in timing relationship. Timing control circuit 8244 also preferably generates the start bit which is preferably as described in the aforementioned copending U.S. patent application. The selected data with the inserted bit is provided via path 8255 to a sync insertion circuit 8248 to provide the composite video signal output via path 8253. The sync pulses which are provided to the insertion circuit 8248 are supplied by the TV sync generator 8243 and preferably provide all of the conventional standard vertical and horizontal synchronizing pulses that are normally present on a standard TV signal. The frame enable signal provided to the line select circuit 8245 is preferably timed to allow exactly 235 data lines per TV field. This insures that preferably no data lines are transmitted during the normally blanked periods of television transmission. It also insures that preferably at least three empty lines are pesent after vertical blanking but prior to data transmission. Preferably, during these few preliminary blank lines the start bit is applied to the output signal by start bit insertion circuit 8247. The three empty lines having only a start bit allow the frame grabbing video terminal 28a or 28b to achieve phase lock prior to reception of data at the start of a vertical frame. Detailed function and circuit arrangements for accomplishing the functions of the aforementioned portions 8240, 8241, 8242, 8243, 8244, 8245, 8246, 8247, 8248, and 8256, which provide the various signals present on paths 8249, 8250, 8251, 8252, 8253, 8254 and 8255 shall be described in gtreater detail hereinafter with reference to FIG. 4 and 5 which are detailed schematic diagrams of the preferred embodiment of the master combiner synchronizer 8204 portion of the preferred cable head 13 of the present invention shown in FIG. 1. "Master Combiner Synchronizer Portion" Detailed Description Referring now to FIGS. 4 and 5, which taken together comprise a detailed schematic diagram, partially in logic block, of the preferred embodiment of the master combiner synchronizer portion 8204 of the preferred cable head 13 of the present invention, this portion 8204 shall now be described in greater detail. As previously described with reference to FIG. 3, 8240 is the master synchronizing oscillator which preferably operates at 143.1818 megahertz, and which is preferably a conventional crystal oscillator. The output of the oscillator 8240 is preferably coupled via a level shifting network 8260 to a buffer gate 8261. The buffered output of the oscillator 8240 is provided to a flip-flop 8263 which preferably divides the frequency by two and provides this frequency divided to a counter 8750. This counter 8750 with its associated feedback network preferably provides a division by 7. The output of counter 8750 is preferably provided to another divide-by-2 flip-flop 8264. Thus, the total division of the oscillator 8240 output amounts to a divide-by-28, and, accordingly the output frequency of flip-flop 8264 is 1/2 dof 143.1818 1/28 megahertz oscillator frequency. This establishes the aforementioned 5.113 megahertz signal which is preferably provided as the system data clock. The 143.1818 mmegahertz signal at the output of buffer 8261 is also preferably fed via another buffer 8262 to a divide-by-5 counter 8266. The output counter 8266 is preferably connected to a divide-by-2 flip-flop 8267 to provide at its output a frequency of 14.31818 megahertz which is 1/10 of the oscillator 8240 frequency and is the preferred clock frequency for the TV sync generator 8243, counter 8266 and flip-flop 8267 comprising divide-by-10 network 8242. Preferably all of the aforementioned circuits comprising networks 8241 and 8242 as well as level shifter 8260 and buffers 8261 and 8262, are MECL integrated circuits of the Motorola 10,000 series, by way of example, although other equivalent functioning logic could be utilized. Thus, a buffer and level shifter 8265 which serves to convert the MECL levels of the aforementioned logic to standard TTL levels which are preferably required by the subsequent logic circuitry comprising the preferred master combiner synchronizer portion 8204, is provided, since such subsequent logic is preferably either TTL or TTL compatible logic although, if desired, other equivalent functioning logic could be utilized in place thereof. The level shifter 8265 preferably provides the 14.31818 megahertz clock to sync generator 8243 at two opposite phases of the sync generator 8243, labeled CLK 1 and CLK 2, respectively, in FIG. 4. The sync generator 8243 is preferably a conventional integrated circuit sync generator such as a Fairchild Model No. 3262. The composite blanking signal from sync generator 8243 as well as the data clock signal from level shifter 8265 are both preferably provided to a D type flip-flop 8271. The output of flip-flop 8271 is preferably a resynchronized composite blanking signal which is delayed by one clock period from the input blanking signal. This delayed composite blanking signal as well as the color flag from sync generator 8243 are preverably provided to two inputs of a set/reset flip-flop 8272 to generate the post-sync waveform, such as the waveform illustrated in FIG. 10, by way of example. This post-sync waveform, as illustrated in FIG. 10, establishes a period of time near the end of the horizontal blanking interval and immediately preceding the start bit of a pseudo video TV scan line. A bit counter 8273 is preferably utilized to establish the start time for each character, that is the beginning of each 7 bit sequence. During the post-sync waveform the bit counter 8273 is preferably continously preloaded to a count of 9 by the data clock. At this time the carry out line of the counter 8273 is preferably high. As soon as the post-sync signal is removed, the counter 8273 is preferably reloaded to a count of 3 and then is alloed to count until the carry out is again asserted at count 9, this cycle continuing with the counter 8273 being reloaded to 3, counting to 9 and being reloaded. This preferably continues for the duration of any pseudo video TV scan line. The aforementioned carry out line of bit counter 8273 is preferably provided to the D input of a D type flip-flop 8274. This flip-flop 8274 is preferably clocked by the data clock, and, thus, has an output which is preferably asserted for 1 bit time and delayed by a 1/2 clock bit time from the carry out of the counter 8273. The output of 8274 is the aforementioned load enable pulse whose waveform is also illustrated by way of example in FIG. 10. Bit counter 8273 also preferably controls another flip-flop 8275 which flip-flop 8275 preferably generates the start bit, the D output of counter 8273 preferably being provided to the clear input of flip-flop 8275. Flip-flop 8275 is preferable initially clocked to a set state by the trailing edge transition of the composite blanking signal from flip-flop 8271. This transition establishes the beginning of the start bit. Preferably, one bit time later, bit counter 8273 transfers from a count of 9 to a count of 3. At that time its D output preferably goes from high to low thereby clearing flip-flop 8275 and terminating the start bit. Another flip-flop 8276 and a gate 8277 are preferably provided in order to remove the first start bit that occurs during any vertical frame as the first horizontal line in the TV frame can be a half line and it is preferably not desired to ave a start bit on such a half line. flip-flop 8276 is initially cleared by the vertical drive pulse and, in its cleared state, presents a low level to gate 8277. Thus the start pulse at the output of flip-flop 8275 cannot be passed through gate 8277 while flip-flop 8276 is cleared. After the completion of the first start bit flip-flop 8276 is set and subsequent start bits are allowed to pass through gate 8277. Counters 8268 and 8269 and another flip-flop 8270 are also provided and are preferably utilized to establish the frame enable period. The counters 8268 and 8269 are preferably initially loaded to a composite value of 239. Clock pulses which are provided subsequent to the removal of the vertical drive pulse preferably cause the counters 8268 and 8269 to decrement. Preferably, when the counters 8268 and 8269 count down to a value of 235, the C output of counter 8268 goes low and causes flip-flop 8270 to be clocked to a high state. This preferably establishes the start of the vertical frame enable period. The counters 8268 and 8269 then preferably contiue to decrement until they reach a count of zero. At that time the borrow output of counter 8269 preferably goes low and clears flip-flop 8270 preferably establishing the termination of the frame enable period. All of the aforementioned circuits 8268, 8269, 8270, 8271, 8272, 8273, 8274, 8275, 8276 and 827 preferably comprise timing control circuit 8244. Referring now to FIG. 5, the balance of the circuitry associated with the preferred embodiment of the master combiner and synchronizer 8204 shall now be described. As shown and preferred in FIG. 5, a plurality of switches 8289 are provided to allow the operator to establish the operating mode of the cable head 13. Included in the switch set 8289 are A and B select swtiches 8289a and 8289b, respectively, which allow the operator to turn on or off either of the data channels associated with computers 2000a and 2000b, respectively. The control levels from these switches 8289a and 8289b are provided to gates 8281 and 8282. Also provided to these gates 8281 and 8282 is the frame enable signal output provided from flip-flop 8270 (FIG. 4). A third input to these three input gates 8281 and 8282 is provided from another flip-flop 8280. This flip-flop 8280 is toggled by the post-sync waveform with opposite signal levels being provided to each of the gates 8281 and 8282 in such a way that alternately one output is enabled and then the other output is enabled in synchronism with the frame enable signal provided to the gates 8281 and 8282. Each output is enabled only if its corresponding A (8289a) or B (8289b) select switch is on. The outputs of gates 8281 and 8282 preferably comprise control signals which are provided to the two transmitters 8202a and 8202b as illustrated in FIG. 1. These output control signals are utilized to authorize each transmitter portion 8202a and 8202b to process a pseudo TV scan line. The line enable signal outputs of gates 8281 and 8282 are also preferably provided to gates 8283 and 8284. These are the gates to which the data lines from the transmitters 8202a and 8202b are provided. Thus data is present alternately at the output of gate 8283 and gate 8284. These data lines are provided to two of the three inputs of a three input NOR gate 8285 along with the start bit which comes from gate 8277 (FIG. 4) and which is provided to the third input. Thus the output of gate 8285 contains the selected pseudo video data line and the start bit. The output of gate 8285 is provided to another gate 8286 which passes this signal but is also controlled by the composite blanking waveform or signal to preferably insure that no extraneous data is present during the blanking period. Thus the output of gate 8286 is the composite data line that contains all of the serial data. Because of the number of gates and logic inversions that various components of the signal have come through up to this point, there is no guaranteee at this point that all data pulses have the same width. For this reason the data is preferably resynchronized by another flip-flop 8287. Circuits 8285, 8286 and 8287 comprise start bit injection circuit 8247. At every position going transition of the data clock the D input of flip-flop 8287 is sampled to set the status of the flip-flop output. Thus the output of the flip-flop 8287 preferably follows the data input except that it is one half clock period delayed, with every data pulse being exactly of the same width. The output of flip-flop 8287 is provided to a resistor network 8293 which forms a summing network which combines the data and sync levels. The other input to the resistor summing network is the composite sync waveform from sync generator 8243 (FIG.4) which is provided via an inverter 8294. Adjustable resistors are provied at each input of the summing network 8293 so that the sync/data ratio can be precisely set. The output of the resistor summing network 8293 is preferably provided to a conventional emitter follower circuit 8296. This circuit 8296 preferably provides a low impedance, such as 75 ohms, output sufficient to drive the subsequent pre-equalization filter 8207 illustrated in FIG. 1 via the composite video provided via path 8253. Circuits 8293 and 8296 comprising sync insertion circuit 8248. The color subcarrier from sync generator 8243 (FIG. 4) is provided to a conventional transistor amplifier circuit 8288. This amplifier 8288 is preferably tuned to the 3.58 megahertz frequency of the color subcarrier and preferably has an adjustable resistor 8288a in its emitter circuit to permit adjustment of the color burst output amplitude of the amplifier 8288. The output of the amplifier 8288 is preferably provided along with the color burst flag from the sync generator 8243 to the color burst gate 8256. This gating circuit 8256 preferably consists of a conventional transistor amplifier so connected that the amplifier can be turned off by the color burst flag. Thus its output consists of a burst of the color subcarrier which occurs during the time established by the color burst flag. This output, which is provided on path 8250, is preferably provided at a low impedance to the output network 8206 as shown and preferred in FIG. 1. The other switches of the switch bank 8289 specifically the A and B control switches 8289a and 8289b, respectively, are used to provide enabling levels to the transmitter portions 8202a and 8202b, as will be described in greater detail hereinafter. Preferably, a plurality of light emitting diodes 8290 are also provided to provide indicator signals. A and B transmit indicators 8290a and 8290b, respectively, are lit when the corresponding transmitter portion 8202a or 8202b, respectively, is transmitting data. A and B status indicators 8290c and 8290d (for A status) and 8290e and 8290f (for B status), respectively, are lit in accordance with data bits from the status register in the corresponding transmitter portions 8202a and 8202b, respectively. The derivation of the respective driving signals will be described in greater detail hereinafter. As shown and preferred in FIG. 5, output inverters 8300 and 8301 provide buffering and inversion of the various signals provided from the portion of the master combiner synchronizer 8204 shown and described in FIG. 4. The outputs of inverters 8300 and 8301 are preferably provided to transmitters 8202b and 8202a, respectively. As used throughout the specification and drawings, the letters L or H following a waveform description refer to positive or negative logic definitions of the signal; that is, by way of example, post-sync L refers to a waveform which is at its low level during the period of post-sync, whereas post-sync H would be the high level or inversion of this signal. This is true for all of the exemplary signals defined and shown in the drawings relating to the preferred embodiment of the present invention. As shown and preferred in FIGS. 5 and 8, the various signals which are provided to and from the transmitter portions 8202a and 8202b and the master combiner synchronizer 8204 are as follows. With respect to transmitter portion 8202a, the respective signals which are provided between transmitter portion 8202a and master combiner synchronizer 8204 are the data L signal which is the data A L input to the master combiner synchronizer 8204 via path 8310, and the following signals provided via paths 8311 through 8317 from the master combiner synchronizer 8204, respectively labeled load enable H, vertical drive H, phase lock H, post-sync L, switch 2 H, switch 1 H, and select me H. The various status indicator lamps 8290a, 8290c and 8290d associated with transmitter 8202a, are preferably controlled via signals provided via paths 8318, 8319, 8320. An EVEN line enable signal is provided via path 8321 as an output signal which is the line enable H signal output of data select 8246 which is provided from gate 8324 of data select 8246. Intercontrol signals output H and input H are provided via paths 8322 and 8323, respectively, between the transmitter portions 8202a and 8202b. With respect to transmitter porion 8202b as shown and preferred in FIGS. 5 and 8, the respective signals provided between transmitter portion 8202b and the master combiner synchronizer 8204 are, respectively, the data L signal which is the data B 1 signal input to the master combiner synchronizer 8204 provided via path 8325, and respective output signals load enable H, veritcal drive H, clock H, post-sync L, switch 2 H, switch 1 H and select me H provided via paths 8326 through 8332, respectively, with the signals on paths 8317 and 8332 being the transmitter 8202a and 8202b select signals, respectively, and with the control signal for the status lights 8290b, 8290e and 8290f associated with transmitter 8202b being preferably provided via paths 8333, 8334 and 8336, respectively. An ODD line enable signal is provided via path 8335 as an output signal which is the line enable H signal output of data select 8246 which is provided from gate 8337 of data select 8246. "TYPICAL TRANSMITTER PORTION" Detailed Description Referring now to FIGS. 6 through 8, the typical preferred transmitter portion 8202a of the preferred cable head 13 of the present invention shown in block in FIG. 1, shall now be described in greater detail, the other typical preferred transmitter 8202b comprising the preferred cable head 13 preferably being identical in function and operation with transmitter portion 8202a as previously mentioned. FIG. 6 shows those portions of the transmitter circuit 8202a which receive data from the conventinal computer 2000a. Connectors 8640 shown illustratively in two parts labeled 8640a and 8640b, respectively, interconnect the transmitter 8202a with the associated computer 2000a. This connector 8640 is used for both the input and output lines. Data from the computer 2000a is preferably fed on parallel lines in either a 12 bit or a 14 bit configuration depending on which type of computer is utilized. Integrated circuits 8601 through 8604 which are conventional line transceiver circuits are provided and serve to receive data from the computer 2000a or to transmit data back to the computer 2000a depending upon which mode the transmitter 8202a is operating in. As was previously described, data transfer takes place in either of two modes; one mode is a direct memory access mode wherein data is fed continuously at maximum rate from the computer 2000a memory unit directly to the transmitter 8202a and the other mode is the status transfer mode which is utilized primarily for single word transfers in both directions. In both modes certain control and acknowledgment signals are preferably required between the computer 2000 a and the transmitter 8202a to establish valid times for receiving and returning data. Considering first the direct memory access mode, a control signal from the computer 2000a is preferably applied to an inverter 8608 to initiate this mode of operation. This signal is preferably asserted when the computer 2000a is ready to transmit data by direct memory access. A NAND gate 8605 is provided which is an enabling gate which receives the ready command from an inverter 8608 and also has a second enabling input provided thereto from the transmitter 8202a first in-first out buffer via path 8644. This circuit will be described in greater detail hereinafter, but suffice it to say at this time that this line must be asserted before data can be received by the transmitter 8202a. A third input is preferably provided to gate 8605 from a pair of inverters 8610 and 8611 which are connected to the computer 2000a along a path which is always asserted at the time that data break is initiated and serves to terminate the data break at the proper time. With all enabling input conditions at gate 8605 met, the output of that gate 8605 preferably falls to a low level which is provided to the D input of a D type flip-flop 8606. This flip-flop 8606 is preferably clocked by the transmitter 8202a data clock and, accordingly, the output of the flip-flop 8606 falls at the initiation of the next clock pulse. Similarly, a following flip-flop 8607 preferably responds to the next succeeding clock pulse and its output is asserted at that time. This output signal is transmitted via an inverter 8609 back to the computer 2000a as an acknowledgement that the ready status of the computer 2000a has been received and, furthermore, that the transmitter 8202a is ready to accept data. The sequence of events that then follows is that the computer 2000a applies valid data to the data line received by line transceivers 8601 through 8604. At this time the controlline 8643 preferably sets the line transceivers 8601 through 8604 in their received state. In this state, the line transceivers 8601 through 8604 preferably pass data from the input to output lines which are then applied to the nput of the first in-first out buffer which will be described in greater detail hereinafter. Returning once again to the control circuit, and specifically to gate 8605, once data has been strobed into the first in-first out buffer the FIFO IN ready line 8644 drops to a low level. Preferably, after two clock delays, the acknowledgment signal to the computer 2000a has returned via inverter 8609 and is returned to its original state. This signifies that the first data word has been received by the transmitter 8202a. A second cycle of control command acknowledgement and data word reception then follows, preferably exactly in the manner described above for the first word.This process continues as long as the computer 2000a remains in its direct memory access mode. At the completion of the data break, the DONE line from the computer 2000a, which is applied to inverter 8610, signifies that the data break has been completed and disables gate 8605. This terminates the direct memory access mode. Control of the other mode, that is status transfer is accomplished by the interconnection between the transmitter 8202a and the computer2000a shown at 8640b. This operation is preferably initiated by the INTERRUPT OUT line from the computer 2000a applied to an inverter 8614 being asserted. As a result of this assertion, another inverter 8615 presets a flip-flop 8618 and a NOR gate 8616 clears another flip-flop 8617. Flip-flop 8617 is connected to the clock input of flip-flop 8618 which in its preset state enables gate 8622. The data clock, which is applied to the other input of gate 8622, is then applied to the computer 2000a via the INTERRUPT IN line by way of inverter 8263. Transmission of this train of clock pulses from the transmitter 8202a to the computer 2000a is the transmitter's 8202a acknowledgement to the INTERRUPT OUT command. Preferably, at this time the computer 2000a applies a status word to the data input lines which are connected to transceivers 8601 through 8604. A control line 8643, which is connected to the output of flip-flop 8617, is preferably still in the state which sets the line transceivers 8601 through 8604 in the receive mode. Thus, the transceivers 8601 through 8604 make availabel at their output the status word and this word is applied to the inputs of conventional latches 8612 and 8613. After a short time has passed sufficient to insure that the data lines have stabilized, the computer 2000a asserts the INTERRUPT ACTIVE line going to the transmitter 8202a and received therein at an inverter 8619. The output of the inverter 8619 is preferably applied to the D input of another D type flip-flop 8620 so that at the initiation of the next subsequent clock pulse output of that flip-flop 8620 is asserted enabling a gate 8621 whose output then drops to its low state; the output of gate 8621 being fed as the strobe input to the latches 8612 and 8613, the data applied to the latches 8612 and 8613 preferably being strobed into the latches 8612 and 8613 at the falling edge of this signal. The data remains at the output of the latches 8612 and 8613 preferably until at some later time when the status word reception cycle is repeated. At this time both the INTERRUPT ACTIVE line and the INTERRUPT OUT line applied to inverters 8614 and 8619 are preferably returned to their original state under control of the computer 2000a program. This completes the status word output transfer from the computer 2000a. Preferably, automatically and immediately following a status word output transfer from the computer 2000a, a status input transfer is accomplished. This is accomplished as follows. On the next clock pulse following return of the INTERRUPT ACTIVE line to its original state, the output of flip-flop 8620 is set at a high level. This transition applied to the clock input of flip-flop 8617 causes the output of flip-flop 8617 to change state; that is, to go from a high to a low level. This low level is preferably applied to the control line 8643 of the input transceivers 8601 through 8604 to set them in the transmit mode. In this state, the line transceivers 8601 through 8604 connect their input line 8648a and 8646b to the computer 2000a data bus through connector 8640a. The origin of these lines which provide the output status word will be described in greater detail hereinafter. Suffice it to say at this time that we have thus far described how under the direct memory access mode, data is received from the computer 2000a and applied to the FIFO input lines 8648; that during a status output transfer the computer 2000a output status word is latched into buffers 8612 and 8613 and made available at the output of these latches 8612 and 8613; and that during a status input transfer to the computer 2000a, the data on lines 8646 is applied to the computer 2000a data bus. It should be noted that line transceiver 8601 is preferably utilized only when the transmitter 8202a is fed from a 16 bit computer; when a 12 bit computer is utilized instead for computer 2000a, transceivers 8602 through 8604 process the 12 bits and line transceiver 8601 is not needed. Furthermore, when a 12 bit computer is utilized, one 12 bit word is preferably utilized to transfer two 6 bit characters. The transmitter 8202a preferably has the capability of operating with 7 bit characters. A unique feature of the present invention is that it provides a capability to generate a seventh bit for at least certain characters by use of the status word. This feature generally is useful only when it is desired to set the seventh bit of some character at a value and to leave it at the same value for a very large number of consecutive character transmissions. This is precisely the situation that is often required for setting up a seventh bit for group addresses and for special characters in the row grabbing system described in the aforementioned copending U.S. patent application. The particular bits which are used for seventh bit generation are preferably connected from the status word latches 8612 and 8613 to a multiplexer 8627 and are preferably selected by the multiplexer 8627 to be made available at the correct time at the output of the multiplexer 8627. Now describing the circuit components that do the word counting as necessary to control the multiplexer 8627. One of the preferred basic functions of the transmitter 8202a is to format the words received by the computer 2000a into serial output data packets which contain 38 characters. These packets comprise the data content of the pseudo video scan lines. Since the first in-first out buffer is preferably loaded with words which consist of two characters each it is necessary to preferably count 19 outputs of the FIFO to determine the completion of one data packet. Conventional word counters consisting of 8626, 8628 and 8629 accomplish this counting. At the beginning of any television scan line all counters 8626, 8628, and 8629 are cleared by the post-sync pulse provided via path 8750. Everytime a word is transferred out of the FIFOs, a clock pulse is made availabel for the counters 8626, 8628 and 8629 on line 8649. When counter 8626 is set at count 0, that is its initial condition, multiplexer 8627 preferably selects the C 0 input line from the plurality of inputs 8651 to multiplexer 8627 and applies it to one output 8653 thereof. At the same time, it selects the C 0 input to multiplexer 8627 from the plurality of inputs 8652 and applies it to the 8654 output line. Preferably when the first word has been strobed out of the FIFO, counter 8626 advances to count 1 and the multiplexer 8627 selects line C 1 of plurality 8651 to be connected to output 8653 and selects also line C 1 of plurality 8652 to be applied to output line 8654. This process continues up to a count of 3 when, at the same time a gate 8625 applies a low level to the enabling inputs of counter 8626 and halts its counting operation until it is recleared at the start of the next television scan line. As a result, the multiplexer inputs C 3 of 8651 and 8652 are connected to the two output lines 8653 and 8654, respectively, for the remainder of the television scan line. As a result of these connections, it is possible for the computer 2000a to establish unique bit assignments for the seventh bit of each of the initial address characters and to establish a fixed bit assignment for all of the data characters. Odd and even data character 7 bits, however, are preferably selected separately so that the result is that the seventh bit of all odd data characters will have one value and the seventh bit of all even data characters will have a value which may be the same or different as that of the odd characters. The remaining circuit components shown in FIG. 6 are preferably utilized to establish initialization and reset conditions, such as the input circuit to an inverter 8637 which with a subsequent inverter 8638 is utilized to provide a negative initialization pulse when power is first turned on. As a result, initialization pulses are made available at the output of inverter 8638, at the output of a gate 8636, and at the output of a NOR gate 8633. Means is also provided for a reset pulse to be generated under computer 2000a control. This is accomplished during data output transfer by the computer 2000a setting the bit of the status word that ends up on line 8653 applied to NAND gate 8635. As a result of the signal on line 8661, a reset pulse is generated by NAND gate 8635 during every status transfer, during which time the other input to gate 8635 also goes high. Thus, as long as the line 8661 remains high, reset pulses will be continuously generated. Normally the status word is preferably set to cause a reset on one status transfer, a reset pulse having been created thereby as previously mentioned, the reset bit being cleared on the subsequent status word transfer. The reset pulse from gate 8635 preferably causes a FIFO reset from gate 8636 and causes flip-flop 8634 to be cleared. With flip-flop 8634 cleared, a reset assertion is made at the output of gate 8632 and appears at the output of gate 8633 as a master reset pulse labeled RESET L. This particular reset pulse is preferably removed at the start of the next vertical drive period by flip-flop 8634 which is preferably clocked to its set state at the start of the vertical drive pulse provided at the clock input of flip-flop 8634. A slightly different form of reset under computer 2000a control is preferably accomplished when the computer 2000a sets the bit of the status word associated with line 8660. With this bit set, gate 8624 applies a negative reset pulse to gate 8632 during every status word transfer. In similar manner as in the previously described reset mode, a reset negative level is preferably provided at the output of NOR gate 8633. In this case, the reset is under direct control of the status word bit, whereas when the reset was generated by flip-flop 8634, the reset condition once started was maintained until the start of a vertical drive pulse. The reset associated with flip-flop 8634 is preferably utilized when it is specifically desired to halt transmission of data characters and to resume transmission at the start of the next vertical field. The status output bits labeled, respectively, INTERCONTROL OUT H, LAMP 2H, and LAMP 1H, on lines 8665 through 8667, respectively, are preferably utilized for signal indication and control purposes which will be described in greater detail hereinafter. Referring now to FIG. 7, character input data is preferably applied via lines 8648a and 8648b to FIFOs 8670 through 8673. The FIFOs 8670 through 8673 are initially cleared by the reset line 8688. Data is strobed into the FIFOs 8670 through 8673 by the FIFO strobe line 8690 which is generated by flip-flop 8607 (FIG. 6). The FIFOs 8670 through 8673 preferably have capacity for storing 64 words. After the FIFOs 8670 through 8673 have been cleared and at least one word has been strobed in, data shortly becomes available at the FIFO output line. Availability of data at the output is signalled by the OUTPUT READY lines which are connected to gate 8675 and 8676. Thus, a high level at the output of gate 8676 indicates that all FIFOs 8670 through 8673 have valid output data available. Similarly, each FIFO 8670 through 8673 has a line which indicates that its input is ready to receive data. The INPUT READY lines are preferably connected to gates 8674 and 8677 such that the output of gate 8677 is high when the inputs of the FIFOs 8670 through 8673 are ready to receive data. The function of the INPUT READY high line 8644 was previously described in relation to the portion of the transmitter 8202a shown in FIG. 6. The circuits consisting of components 8678 through 8686 are preferably utilized for the purpose of computing and inserting a check sum at the end of a data packet. These circuits 8678 and 8679 are preferably conventional binary adders which are connected to add two 7 bit numbers. The bits of one number are preferably connected to the A inputs and the bits of the other number are preferably connected to the B inputs. The 7 bit sum is then available at the output lines. The units are preferably connected so a carry is correctly propagated from the least significant bit to the most significant bit; however, no carry output is generated. As shown and preferred, the adders 8678 and 8679 add together the two 7 bit characters which are always available at the 14 bit output lines of the FIFOs 8670 through 8673. Thus to start with, character 1 is added to character 2 to make their sum available at the output; then, after the next word is available at the FIFOs 8670 through 8673, character 3 is added to character 4, and so forth. This operation preferably continues for the duration of each data packet. Circuits 8680 and 8681 are also preferably binary adder circuits identical to adders 8678 and 8679. These adders 8680 and 8681 add the previous sum made available by adders 8678 and 8679 to another 7 bit number which preferably comes from a conventional storage latch 8682. For the purpose of discussion it is assumed initially that the output of latch 8682 is zero. In that case, the summation outputs of adders 8680 and 8681 are the same as the input values. Thus at the time just prior to the strobing of characters 2 and 3 out of the FIFOs, the sum of characters 1 and 2 is available at the output of adders 8680 and 8682. At the occurrence of the first FIFO strobe output on line 8690, two things happen simultaneously. First, the output of adders 8680 and 8681, namely the sum of the first two characters, are latched into buffer latch 8682 and made available at the output line of that circuit 8682. Then, the second and third characters are made available at the output of the FIFOs 8670 through 8673. As a result, at this time, connected to the input of adders 8680 and 8681, are the summation of characters 1 and 2 on one set of inputs and the summation of characters 3 and 4 on the other set of inputs. This results in, at the output of these adders 8680 and 8681, the presence of the total summation of characters 1, 2, 3 and 4. Thus, as the line progresses, at all times available at the output of adders 8680 and 8681 is the total accumulated sum of all characters transmitted up to that point. Preferably, after characters 37 and 38 have been strobed out of the FIFOs, the output of adders 8680 and 8681 represents the check sum of the 38 characters processed up until that time. Actually, as presently preferred, the last data character is character number 37. However, since characters are preferably handled inpairs, a dummy 38th character is included in the addition but the computer 2000a sets that dummy character to a value of zero. Thus, the summation represents the addition of characters 1 through 37. A plurality of inverters 8683 preferably form the ones complement of the check sum and provide it at the input lines of conventional multiplexers 8685 and 8686. These multiplexers 8685 and 8686 preferably serve to switch these check sum lines onto the output data lines n place of the FIFO data at the precise time necessary for the check sum to be picked up as the 38th output character. As a result, the 14 output lines 8695a through 8695n represent the character pairs necessary to form the proper final output data including the check sum. The switching of these multiplexers 8685 and 8686 is preferably accomplished by the control line 8696 labeled CHECK SUM SELECT H. This line 8696 is preferably asserted at the 18th count of the word counter 8629 (FIG. 6) which signal would then be present at the output of gate 8631 (FIG. 6). Referring now to FIG. 8, conventional shift registers 8700 and 8701 are preferably provided to convert the 14 bit parallel input data provided via lines 8695a-8695n into serial data as necessary for final transmission. A negative pulse on line 8711 which preferably occurs once per character, preferably latches the parallel input data provided via 8695a-8695n into the shift registers 8700 and 8701. This data is then preferably shifted out serially under control of the 5.1 megahertz system clock provided via line 8712. A conventional multiplexer 8702, illustratively shown in two sections 8702a and 8702b is provided, with section 8702a connecting the output data line alternately to the output of one or the other of the shift registers 8700 or 8701. The multiplexer 8702 is preferably switched at the character rate by control line 8714 which is shown connected as the control input to the other section 8702b of the multiplexer 8702. The output data from section 8702a is preferably connected to an inverter 8715 which makes the final output data available on line 8716. The other circuits shown in FIG. 8 are preferably utilized to generate control waveforms necessary to operate the various circuits of the transmitter 8202a already described. Flip-flops 8703 and 8704 are preferably provided to generate an initial delay after the FIFOs 8670 through 8673 first have data available. Inasmuch as data is preferably shifted out at a fixed rate for one television scan line period, preferably it is desired to insure that the FIFOs are adequately loaded with data before a line transmission is initiated. Flip-flops 8703 and 8704 thus provide an initial delay after reset equivalent to two television scan line periods which is an adequate time to insure that the computer 2000a has loaded the FIFOs 8670 through 8673 with adequate data. A three input gate 8705 is provided which tests its input lines 8720, 8721 and 8722 to determine if all conditions are met for initiating the transmission of a data packet. If the system is still in reset, as indicated by a signal present on line 8720, if the FIFOs output are not ready as indicated by a signal present on line 8721, of if the LINE ENABLE is not asserted on line 8722, the output of gate 8705 will be low and the system will be inhibited from transmitting a data packet. The aforementioned LINE ENABLE line 8722 is the one that selects which of the two transmitters 8202a or 8202b is used for a particular television scan line. When all conditions necessary for transmission are present, the output of gate 8705 goes high and at the trailing edge of the next post-sync pulse, provided via line 8750, flip-flop 8706 is set. This flip-flop 8706 preferably initiates a transmission sequence by removing the clear condition from the shift registers 8700 and 8701 and from flip-flops 8707 and 8708, the FIFO flip-flops, and the character ODD/EVEN flip-flop. One output of flip-flop 8706 preferably enables the multiplexer 8702b via path 8730. Flip-flop 8708 is preferably toggled at the character rate to generate the select input for mulitplexer 8702 on control line 8714. The LOAD ENABLE waveform is connected to both the J and the K inputs of J-K flip-flop 8707 via line 8731. This pulse on path 8731 is preferably one clock period long. Thus, the flip-flop 8708 is toggled at the negative clock transition which occurs during the LOAD ENABLE pulse. The output of flip-flop 8708 provided via line 8714 is preferably high during odd character periods and low during even character periods. One input of multiplexer section 8702b is preferably connected to the LOAD ENABLE line 8731 while the other input is grounded. Therefore, the output of this multiplexer section 8702b which is provided via line 8713 consists of alternate LOAD ENABLE pulses. Thus output line 8713 is preferably connected to the K input of flip-flop 8707. As a result, the output of flip-flop 8707, which is provided via line 8735, is set high at the completion of the last bit of each odd character and remains high during the first bit of the subsequent even character. Thus, this line 8735 is high during the first bit of even characters 2, 4, 6, etc., and is low at all other times. Preferably, at the completion of an active television scan line, the transmit sequence is terminated by the word 18 pulse which is provided via line 8737. This is preferably applied to the clock input of the LINE DONE flip-flop 8709 via an inverter 8738. As a result, at the completion of word 18, flip-flop 8709 is set and its output provided via path 8739 goes low, clearing the READY flip-flop 8706. The output of flip-flop 8706 then returns to its original quiescent state. It should be noted that in the preferred example being described herein, the completion of the word 18 pulse corresponds to the completion of dummy character number 40. This is because the word 18 pulse actually is present during words 18 and 19, and as shown in FIG. 10, the completion of word count 19 preferably occurs when characters 39 and 40 are present at the FIFOs output. As further shown and preferred in FIG. 8, inverters 8740, 8741 and 8742 are provided as lamp drivers to provide power to the signal indicator lamps via signals LAMP 1 L, LAMP 2 L, and TRANS, LAMP L, respectively. As was previously mentioned, the function and operation of transmitter portion 8202b is preferably indentical with that described above with reference to the function and operation of transmitter portion 8202a, described in detail above. As was also previously mentioned, these tramsitter portions 8202a and 8202b preferably provide serial data unidirectionally to the master combiner synchronizer 8204 as well as receiving and transmitting bidirectional status and control signals to the master combiner synchronizer 8204. The output of the master combiner synchronizer 8204, which was previously described in detail with reference to FIGS 4 and 5, is the composite video signal and a separate color burst signal both of which are provided to the output network 8206, as shown and preferred in FIG. 1. The function and operation of this output network 8206 for providing a well defined controllably distorted output signal of the type represented by the waveform illustrated in FIGS. 11C and 11E shall now be described in greater detail hereinafter with reference to FIGS. 9 and 11A through 11E. Pre-Post Equalization of a CATV Channel As was previously described in the commonly owned copending U.S. patent appliction "Improved Row Grabbing System", filed Sept. 10, 1975 and bearing U.S. Ser. No. 611,843, and as particularly illustrated in FIGS. 21A through 21C thereof, data to the receiver terminal 28a or 28b may contain significant distortion resulting from conventional vestigal sideband modulation schemes utilized for the preferred CATV transmission as well as from phase delay distortion present in any cable or CATV transmission system and the bandwidth limitations inherent in the FCC channel allocations. These distortions generally occur in any television transmission and are not normally compensated for due to the low level fidelity requirements of conventional television transmission and display. The nature of these types of distortions was described in the aforementioned U.S. patent application and illustrated in FIGS. 21A through 21C thereof. FCC channel allocations normally provide for equalization with respect to conventional television transmission; however, this equalization is not sufficient for the type of digital data transmission which is accomplished by the preferred system of the present invention and, thus, the aforementioned distortions occur. The preferred equalization system of the present invention which, as will be described in greater detail hereinafter, preferably takes place in output network 8206, as well as in the preferred RF demodulator/equalizers 8850a and 8850b which are preferably identical channel type dedicated equalizers, omits the need for the distortion compensation cirucit of the type described in the aforementioned U.S. patent application. Referring now to FIGS. 9 and 11A through 11E, the output network 8206 shown in block in FIG. 1, shall now be described in greater detail with reference to the schematic of FIG. 9. The illustrations of the various exemplary waveforms present throughout the output network 8206 shown in detail in FIG. 9 are shown in FIGS. 11A through 11E. FIGS. 11A through 11C refer to the various exemplary waveforms present at points A, B and C (FIG. 9), respectively in the output network 8206. FIG. 11D refers to the exemplary energy distribution of the waveform illustrated in FIG. 11A and FIG. 11E refers to the exemplary energy distribution of the waveforms illustrated in FIGS. 11B and 11C, the energy distribution of the waveforms illustrated in FIG. 11C being the same as that of the waveform illustrated in FIG. 11B. The preferred pre-equalization filter network 8207 is preferably utilized in output network 8206 to limit the energy content of the composite video input data signal, illustratively represented by the waveform of FIG. 11A, and provided via path 8253 to filter 8207 at point A, without adding any significant group delay distortion. This pre-equalization filter 8207 produces an output signal at point B from the input waveform of FIG. 11A which output signal is represented by FIG. 11B. The waveform of FIG. 11B preferably has an energy distribution of the form illustrated in FIG. 11E. Thus, as can be seen by comparing FIG. 11D, the energy distribution of the input waveform of FIG. 11A, and FIG. 11E, the energy distribution of the output waveform of FIG. 11B, the energy distribution of the signal provided at the output of pre-equalization filter 8207 is preferably brought well within the restrictions of the CATV transmission system being utilized. Thus, this signal present at the output of filter 8207 will not be significantly distorted by the CATV transmission system utilized with respect to the band limiting distortions which would normally occur in the absence of the pre-equalization filtering function of filter 8207. As shown and preferred in FIG. 11B, this output signal as compared to the input waveform of FIG. 11A is a controllably distorted digital signal well defined in accordance with the characteristics of the preferred filter network 8207 to be described in greater detail hereinafter. As shown and preferred in FIG. 9, the output of the preferred filter network 8207 is provided to the base of a buffer amplifier 8500, which is preferably a conventional transistor amplifier, which prevents overloading of filter 8207 in conventional fashion. This buffer amplifier 8500 preferably feeds one input to mixer or summing network 8209 such as one preferably comprising resistors 8501 and 8502, with the other input to the mixing network 8209 preferably being the color burst signal provided via path 8250 through resistor 8502. The output of the summing network 8209 is preferably provided through a capacitor 8503 which conventionally provides AC coupling into the AC coupled output amplifier comprising the video driver 8208. Amplifier or video driver 8208, preferably contains a group delay equalizing network comprising resistors 8504, 8505 and capacitor 8506. Network 8504-8505-8506 preferably compensates for the distortion introduced by envelope detection of vestigal sideband TV demodulation. Thus, network 8504-8505-8506 preferably introduces the specific type of distortion required for the RF demodulator/equalizer 8850a and 8850b used for a given channel in the CATV transmission system utilized. The output of the video driver 8208 which is illustratively represented by the waveform of FIG. 11C, thus preferably contains further controllable distortions therein. These further controllable distortions which are now preferably present in the waveform of FIG. 11C, when passed through the cable TV television distribution system in which signal distortions of the type which normally result from the vestigal sideband modulation and demodulation process occur, and through the RF demodulator/equalizer 8850a and 8850b associated with the channel, result in the waveform of the type illustrated in FIG. 11B at the output of the RF demodulator/equalizer 8850a or 8850b. Thus, when the distortions which normally occur due to this vestigal sideband modulation and demodulation occur on or are combined with the signal of the type illustrated in the waveform of FIG. 11C, it preferably results in the output waveform illustrated in FIG. 11B at the output of the preferred RF demodulator/equalizer 8850a or 8850b. The configuration of the preferred video amplifier or driver 8208 is preferably a conventional video amplifier of the type utilized in a television distribution system but which has been modified to the extent previously described with reference to the network of 8504-8505-8506. The aforementioned filter network 8207 is preferably a conventional sin 2 filter configuration with the values being chosen so as to preferably limit the energy without adding group delay distortion, as previously mentioned. These values are typically, by way of example, 370μf for the sum of capacitors 8207a and 8207b, 2000μf for the sum of capacitors 8207c and 8207d, 272μf for the sum of capacitors 8207e and 8207f, 250μf for the sum of capacitors 8207g and 8207h, 5.5 to 8.4μh for variable inductor 8207i and 1.8μh for inductor 8207j, and produce a half pulse response whose half amplitude duration is preferably, by way of example, 147 nanoseconds. Thus, output network 8206 as a result of the functioning of filter 8207 and the functioning of network 8504-8505-8506 in video driver 8208, preferably provides a well defined controllably distorted output at point C, illustratively represented by waveform FIG. 11C having a well defined controlled energy distribution, illustratively represented by FIG. 11E, which is well within the capabilities of a standard CATV television distribution system so that any distortions which might normally occur in the signal, provided to the CATV distribution system resulting from the use of such a transmission system are compensated for. It should be noted that unless otherwise indicated in the specification, all circuitry components are preferably conventional although the overall system of the present invention as well as the utilization of such circuitry for the preferred transmission scheme is not conventional. It is to be understood that the above described embodiments of the invention are merely illustrative of the principles thereof and that numerous modifications and embodiments of the invention may be derived within the spirit and scope thereof.

An improved real time frame grabbing system for substantially instantaneously providing a continuous video display of a selectable predetermined video frame of information on a video display means from continuously transmittable video information comprises a plurality of means for transmitting the video information as a plurality of pseudo video scan lines with means being provided for selectively combining and interleaving corresponding identical out of phase digital information content containing pseudo video scan line portions of the plurality of transmission means corresponding pseudo video scan lines to provide an in phase composite combined interleaved pseudo video scan line to the video display means. This composite combined interleaved pseudo video scan line has a television video scan line format and is capable of comprising a complete self-contained composite packet of digital information equivalent in content to the content of either of the interleaved pseudo video scan lines and sufficient to provide an entire displayable row of video data characters to the video display means. The combined interleaved composite pseudo video scan line has an associated transmission time equivalent to that of a television video scan line. The interleaved information containing portions of the corresponding pseudo video scan lines of the plurality of pseudo video scan lines comprise different television video scan lines of the plurality of television video scan lines which comprise the composite pseudo video scan line displayable row. The system further includes television signal distribution means which comprise means for compensating for television transmission distortions in the provided composite combined interleaved pseudo video scan lines provided to the video display means by introducing controllable distortions in the provided composite combined interleaved pseudo video scan line signal prior to the distribution thereof.

BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates generally to digital frequency divider apparatus and more specifically to a frequency divider which will convert the output from a crystal controlled oscillator utilizing a commonly available crystal as its operative element to produce an output pulse train which is compatible with the decimal number system. II. Description of the Prior Art Many types of frequency dividers are known in the digital computing and signal processing arts for converting the frequency of the output from a pulse source to a desired lower frequency. The simplest form of divider for pulse type signals is a bistable flip-flop stage which, when coupled to the pulse source, effectively divides the frequency of this source by two. By cascading plural flip-flop stages, one obtains frequency division by a factor of 2 N , where N is the number of bistable stages utilized. In the digital watch industry, which has experienced drastic growth since the advent of large scale integration of semiconductor devices, a common pulse source utilized is a stable oscillator having a crystal as its frequency determining element. The digital watch industry has generally standardized on a crystal having a natural frequency of 32.768 KHz. When the output from such an oscillator is applied to a 15 stage binary counter, the frequency of the incoming signal is effectively divided by 2 15 or 32,768 to produce one pulse every second. Because crystals having a natural frequency of 32.768 KHz are so commonly used in large quantities in the digital watch field, economies of scale have resulted and such crystals may be obtained at relatively modest cost. Then too, because of their ready availability, their use in electronic devices other than digital chronometers would be advantageous from a manufacturing standpoint, provided a frequency divider can be devised to produce signals of a frequency compatible with these other devices. For example, there is disclosed in the David J. Fischer application Ser. No. 724,019, filed Sept. 16, 1976 and entitled "PROGRAMMABLE DEMAND PACER" a cardiac pacemaker which makes extensive use of digital devices. Timing intervals are established in this pacer unit by driving one or more counters from a digital clock source. In this device, as well as in many others which may be envisioned, it is desirable to produce clock pulses at a frequency which is a predetermined power of 10, e.g., 10 KHz, 1 KHz, etc. If one is to utilize a crystal oscillator having the commonly available digital watch-type crystal used therein, it is desirable to have a frequency divider which will effectively divide the oscillator output by a factor which is other than a power of 2. Specifically, in order to have a clock signal of a frequency of 10 KHz, it would be necessary to frequency divide by a factor of 3.2768. Many circuits have been devised for frequency dividing by various factors. For example, the Pugh U.S. Pat. No. 3,189,832 describes a digital circuit for frequency dividing by a factor (N+1/2) where N is a whole number. Similarly, the Andrea U.S. Pat. No. 3,571,728 describes a frequency divider for effecting division by a factor of N/2 where N is any integer. The Kokado U.S. Pat. No. 3,896,387 illustrates a circuit arrangement for frequency dividing by a factor of 2/N where N is an odd integer. The Patents to Fletcher et al. (U.S. Pat. No. 3,906,374), McGuffin (U.S. Pat. No. 3,943,379), Green (U.S. Pat. No. 3,982,199) and Chiapparoli (U.S. Pat. No. 4,041,403) teach digital circuits for frequency dividing by various other factors. None of the above-described prior art patents, however, teaches or suggests the way in which a pulse train having a frequency which is an integral power of 2 may be frequency divided to produce a lower frequency pulse train which is an integral power of 10. Thus, the prior art has failed to solve the problem of how one might utilize a crystal controlled oscillator which incorporates the commonly available 32.768 KHz crystal ih an electronic device which is designed to employ a clock source operating in the base 10 system. SUMMARY OF THE INVENTION In accordance with the teachings of the present invention, there is provided the design of a digital frequency divider which will accept as its input the output from a pulse source whose frequency is a predetermined power of 2 and which will produce a usable output signal whose frequency is an integral power of 10. To accomplish this end, there is provided a four stage, programmable, binary counter which may have an initial value periodically loaded into the counter. The input signal which is a signal having a frequency which is an integral power of 2 and the binary complement thereof are applied through gating means to the so-called Clock input terminal of the counter. Furthermore, first and second control flip-flops are coupled in circuit with the Carry Out terminal of the counter and with the aforementioned gating means in such a way that one or the other of two binary numbers are alternately entered into the counter each time a Carry Out Signal is generated. The second control flip-flop is coupled to the output from the first flip-flop and its output is, in turn, used to determine whether the incoming signal to be divided or its complement will be used to advance the counter. Using the foregoing circuit arrangement, it is possible to effect division of the incoming signal train by a factor which causes the output from the frequency divider to closely approximate an integral power of 10. Therefore, assuming that the oscillator output has a frequency of 32.768 KHz and that the frequency divider of the present invention effects division by a factor of 3.250, the resulting output from the frequency divider will be approximately 10 KHz. OBJECTS It is accordingly a principal object of the present invention to provide a new and improved design for a digital frequency divider. Another object of the invention is to provide a frequency divider which may be used to convert an incoming signal having a frequency which is an integral power of 2 to an output signal whose frequency is an integral power of 10. Still another object of the invention is to provide a relatively simple frequency divider which will convert a frequency of 32.768 KHz to a frequency of approximately 10 KHz. Yet still another object of the invention is to provide a frequency divider of the type described which is implemented with standard, commercially available integrated circuit devices. Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a logic diagram depicting the preferred embodiment of the present invention; and FIG. 2 illustrates the waveforms observed at various points within the schematic diagram of FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, there is indicated by numeral 10 a crystal controlled oscillator which is adapted to produce regularly occurring square wave signals at a predetermined frequency or repetition rate. In accordance with the teachings of the present invention, the oscillator 10 may comprise a conventional Pierce oscillator incorporating a commonly available crystal as the frequency regulating element thereof, the crystal being of the type commonly used in digital watch type applications. As such, it possesses a natural frequency of 32.768 KHz. Since this frequency is an integral power of 2, specifically, 2 15 , it is readily suitable for use in chronometers in that, by feeding the output therefrom to a 15 stage frequency divider, it is possible to obtain signals at a rate of one per second. However, in other digital devices, it is desirable to work in a decimal number system rather than binary. As such, it is desirable to have a basic system clock rate which is an integral power of 10. Because crystals operating at a natural frequency of 32.768 KHz are so generally used, they are readily available in the marketplace, are extremely accurate, and sell at a reduced cost. It is for these reasons that it becomes desirable to utilize such a crystal in digital circuit applications, other than time pieces and the like. The frequency divider of the preferred embodiment accepts the output signals from the crystal oscillator 10 which may be operating at a frequency of 32.768 KHz and produces an output signal of a frequency which is an integral power of 10, e.g., 10 KHz. The output from the crystal oscillator 10 is applied as an input to an inverter 12 whose output is connected to the input of a second inverter 14 and to a first input terminal of an AND gate 16. Similarly, the output from inverter 14 is coupled to a first input terminal of a second AND gate 18. The output terminals of the gates 16 and 18 are coupled to the input terminals of an OR gate 20. The output from the OR gate 20 is applied to the Clock input terminal (CLK) of a synchronous programmable counter chip 22. In constructing the present invention, the counter chip 22 is preferably a type MC14161 integrated circuit, four-bit, binary counter manufactured and sold by the Motorola Semiconductor Products Corporation of Phoenix, Arizona, but other types of counter devices may also be employed so that limitation to the above indicated type is not intended. As is set forth in the Motorola Product Description relating to the MC14161 chip, these counters are fully programmable; that is, the outputs therefrom may be preset to either binary level. The presetting is synchronous such that when a low binary level is applied at the "Load" input, the counter is disabled for the duration of the Load pulse and the counter's outputs will agree with the input data applied to its terminals P 1 through P 4 following the next clock pulse, regardless of the levels of its "enable" inputs. The counter 22 also includes a carry output terminal labeled "C.O.". A "high" output signal will appear at this terminal when the value registered within the counter reaches 15 10 (1111 2 ). As is indicated in FIG. 1, the carry output terminal C.O. is connected through an inverter 24 to the "LOAD" terminal of the counter. Hence, when the C.O. signal goes high, a low LOAD signal is applied to the counter such that the data present at that time at the input terminals P 1 through P 4 will be registered in the counter. Subsequent pulse signals applied to the CLK input terminal of the counter 22 will then advance the count so entered until the decimal 15 value is again reached, at which time the counter will again be loaded with the binary value present at its P 1 through P 4 input terminals. The output from inverter 24 is coupled by way of a conductor 26 to the CLK input terminal of a first D-type flip-flop 28. As is well known in the art, a D-type flip-flop will be set to the particular binary value which is present at its D-input at the time that a positive going clock signal is applied to its CLK input terminal. The D-type flip-flop has two output terminals labeled Q and Q. When the flip-flop is in its arbitrarily defined Set state, the output appearing at the Q terminal will be high and the output appearing at its Q output terminal will be low. However, when this flip-flop is switched, its opposite state, i.e., its Clear state, the output appearing at the Q terminal will be low and that appearing at the Q terminal will be high. A conductor 30 couples the Q output terminal of flip-flop 28 back to its D-input terminal. The Q output terminal of flip-flop 28 is connected by a conductor 32 to the data input terminal P 1 of the counter 22. The second stage of the counter 22 has its data input terminal P 2 permanently connected to a binary low (ground). Stages P 3 and P 4 of the counter 22 have their inputs connected to a source of positive voltage +V and, as such, are continuously at a binary high value. Thus, when the flip-flop 28 is in its Cleared state, the value entered into the counter 22 upon application of the LOAD enable pulse thereto will be 1100 2 and when the flip-flop 28 is in its Set state, the value 1101 2 will be entered into the counter. The Q output from the flip-flop 28 is coupled by a conductor 34 to the clock CLK input terminal of a second control flip-flop 36. The flip-flop 36 is also a D-flip-flop and a conductor 38 connects its Q output terminal to a second input terminal of AND gate 16. In a similar fashion, a conductor 40 connects the Q output terminal of the flip-flop 36 to a second input terminal of the AND gate 18. The Q output terminal of the flip-flop 36 is also coupled back to its D input terminal by way of a conductor 42. The output from the frequency divider is obtained at the junction point 44 which is connected to the carry output C.O. of the counter chip 22. Now that the construction of the preferred embodiment has been set forth in detail, consideration will be given to its mode of operation. In this regard, reference will be made to the timing diagram illustrated in FIG. 2 which shows the waveforms of the various signals at different points within the circuit of FIG. 1. OPERATION Waveform A illustrates the output obtained from the crystal oscillator 10 as well as that obtained after passing through the two inverters 12 and 14 in FIG. 1. It is generally a square wave signal having a predetermined frequency which is an integral power of 2, for example, 2 15 which is equal to 32.768 KHz. Waveform B represents the signal appearing at the output of the first inverter stage 12 in FIG. 1. It can be seen that it is a signal which is 180° out of phase with respect to waveform A. Depending upon the state of the second control flip-flop 36, either AND gate 16 or AND gate 18 will be enabled to pass either the signals of waveform B or A to the input terminals of the OR circuit 20. Waveform G in FIG. 2 represents the signals appearing at the output from the OR gate 20. Let it be assumed that operation begins at time t 0 when the count registered in the programmable counter 22 changes from 1110 to 1111. While registering 14 10 , just prior to time t 0 , the first control flip-flop 28 is set such that its Q 1 output is low and its Q 1 is high (waveforms C and D, respectively). At this time, the second control flip-flop 36 is also set such that its Q 2 output is low and its Q 2 output is high. (See waveforms E and F.) Because the Q 2 output signal is high, AND gate 18 is enabled by the input thereto applied over line 40. Gate 16 is enabled by the low Q 2 signal applied to it. Hence, it is the double inverted oscillator output signal of waveform A that is passing through the AND gate 18 and the OR gate 20 to the CLK input terminal of the counter 22. When the value in the counter 22 reaches 1111 (15 10 ), it generates a carry output signal, C.O., which appears at the input junction of inverter 24 and which persists for one cycle of the input waveform applied to the counter's CLK input. Waveform I of FIG. 2 represents this C.O. signal at various points in time. The C.O. signal is applied to an inverter 24 whose output is connected to the LOAD enable input of the counter 22 and to the CLK input of the first control flip-flop 28. This signal is represented by waveform H in FIG. 2. Control flip-flop 28 is set at the time that the low LOAD signal is applied to the counter 22 and is followed by a rising clock edge, and the digital value 1100 will be entered into the counter. At time t 1 the LOAD signal goes high and this positive going transition is applied to the CLK input terminal of the flip-flop 28 causing it to be switched to its Set state. As a result, the output signal Q 1 goes high (waveform C). This positive going transition is, in turn, applied to the CLK input terminal of the D-type flip-flop 36 such that it too is Set and its Q 2 output also goes high (waveform E). The high signal is applied by way of conductor 38 to the enable input of AND 16 such that the XTAL output from inverter 12 (waveform B) passes through AND gate 16 and OR gate 20 to the CLK input of the counter 22. Because the counter had been preset to a value corresponding to 12 10 , it will have to receive three positive going transitions before reaching its 1111 2 state. When the all ones state is again reached at time t 2 , the counter 22 will again generate a positive going pulse at its C.O. output terminal. This high signal is inverted by inverter 24 and the resulting low signal, when applied to the LOAD terminal will cause a new data value to be entered into the counter. Because at this time flip-flop 28 is in its Set state, its Q 1 output is high and the value entered into the counter will now be 1101 2 (13 10 ). Now, when the C.O. Signal (waveform I) again goes low at time t 3 , the inverted version thereof again clocks flip-flop 28 to its Cleared state and its Q 1 output signal goes low. A low going signal is incapable of switching the state of the second control flip-flop 36 and it remains in its Set state such that the AND gate 16 remains enabled. Gate 18 is, of course, disabled at this time. After two positive going transitions of the XTAL signals are applied to the counter via the AND gate 16 and the OR gate 20, the counter again reaches its all ones state at time t 4 and another high C.O. output from the counter is generated (see waveform I). Again, by recalling the state of the flip-flop 28 at this time, it will be seen that the counter 22 is again loaded with the binary value 1100 and at the conclusion of the C.O. pulse at time t 5 , the flip-flop 28 is again clocked to its Set state. This action puts a high signal on the CLK input of the second control flip-flop 36 and it returns to its Cleared state. Now, the AND gate 18 is enabled while AND gate 16 is disabled. Hence, the XTAL pulses of waveform A are tallied for the duration that the flip-flop 36 remains in its Cleared state. It may be noted from waveform G that each time that the flip-flop 36 changes state, a phase reversal takes place in the Counter Clock waveform because of the manner in which the signals XTAL and XTAL are selectively applied. By comparing the waveforms, A, B and I, it can be seen that on an alternating basis, three and one half and three cycles occur between successive C.O. signals. More specifically, between time t 1 and t 3 , three and one half cycles of the XTAL input signals occur and that between time t 3 and t 5 , exactly three cycles of the XTAL input occur. Continuing on, between time t 5 and t 7 , three and one half cycles of the XTAL signals take place and between time t 7 and t 9 , exactly three cycles of the XTAL waveform occur. On a continuing basis, then, it can be seen that on the average (3+3.5/2)=3.25 pulses occur between successive outputs on the junction 44 in FIG. 1. Accordingly, the frequency of the incoming signals from the oscillator 10 are effectively divided by a factor of 3.25. With an incoming frequency of 32.768 KHz, the frequency of the output signal appearing at the junction 44 will be approximately 10 KHz. It can be seen, then, that there is provided by this invention, a novel circuit arrangement which may be used to convert the output from a crystal controlled oscillator operating at a nominal frequency of 32.768 KHz, which is an integral power of 2, to a 10 KHz signal, which is an integral power of 10. As such, commonly available crystals which are widely used in the digital watch industry may be utilized in other applications where decimal type operation is desired. For the purpose of illustration only, and with no limitation intended, there is set forth below a designation of the commercially available logic devices which may be used in the implementation of the preferred embodiment: Inverters 12, 14 & 24 -- Type 4049 And gates 16 & 18 -- Type 4081 Or gate 20 -- Type 4071 Flip-Flops 28 & 36 -- Type 4013 Counter 22 -- Type MC14161 It should be further understood that the foregoing disclosure relates only to a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of disclosure which do not constitute departures from the spirit and scope of the invention.

A frequency divider for converting a standard frequency output from a crystal controlled oscillator to a lower frequency which is compatible with digital devices operating in a decimal mode. The oscillator output pulses and the complement thereof are fed to first and second AND gates which are respectively enabled by the complement and true outputs of a control flip-flop. The outputs from these two AND gates are ORed together and applied to the clock input of a synchronous, programmable, multi-bit counter whose carry output terminal is connected to a first D-type control flip-flop, through an inverter, the state of which determines the initial values to be periodically loaded into the multi-bit counter and which also controls the setting of the second D-type control flip-flop.

This is a division of application Ser. No. 188,477, filed Sept. 18, 1980, now U.S. Pat. No. 4,383,508, which is a continuation in part of co-pending application, Ser. No. 22,801, filed Mar. 22, 1979 and entitled Connecting Ros for Oblong Piston for Internal Combustion Engine now abandoned. BACKGROUND OF THE INVENTION The present invention is directed to internal combustion engines and more particularly to internal combustion engines having oblong cylinders. Internal combustion engines have been developed which employ engine cylinders which are not circular in cross-section. These cylinders have been elliptical in the true mathematical sense, oblong and broadly elliptical or oval. In describing such cylinders, the term "oval" will be used to cover rounded cross-sections which are other than circular and which may be truly elliptical or broadly elliptical, e.g. having rounded ends and straight sides. In most cases, engines employing these piston and cylinder configurations were developed as a means for effecting a reduced external dimension of the engine in question without reducing its overall displacement. A variety of configurations have been developed with the long dimension of the engine cylinders both parallel and perpendicular to the crankshaft and one such design has employed two connecting rods associated with the piston for coupling with the crankshaft (British Pat. No. 142,516). The present invention is associated with the development of an oval piston internal combustion engine which is designed for relatively high speed operation. The engine employs a valve configuration which, for volumetric and fluid dynamic reasons (see co-pending application Ser. No. 91,837 filed Nov. 6, 1979), enables productive speeds on the order of 19,000 RPM. With speeds approaching 20,000 RPM, a variety of special conditions must be considered. Among these, friction and internal forces become increasingly important factors in realizing efficient and reliable engine operation. The large inertial effects on the pistons, connecting rods and crankshaft associated with such high speed operation can cause detrimental vibrational effects, particularly in the crankshaft. Principal load requirements on the crankshaft also become more and more imposing with increased engine RPM. The piston may also take on unusual motions at higher RPM's. The normal practice responsive to increased forces is to simply strengthen the components. To this end, a larger crankshaft diameter would normally be warrented. The same is true of the connecting rod associated with the piston. However, these normal practices find disadvantage in the increased inertia and the increased friction resulting from the increase in engine speed. The friction of a rotating bearing increases roughly as a power of 1 to 11/2 of the diameter of the bearing. As greater inertial loads are placed on the crankshaft and connecting rods, greater diameters would normally be employed to resist direct and vibrational loadings. With the increases in crankshaft diameter, friction is rapidly increased. The added inertia also results in greater structural requirements throughout the engine if reliability is to be maintained. Thus, designs employing a substantially strengthened crankshaft and connecting rods have proved to negate some of the power advantages achieved by the unusual engine design. SUMMARY OF THE INVENTION The present invention is directed to improvements in internal combustion engines particularly of the type having engine cylinders which are oval in cross-section. Particular attention is directed to the drive train of the engine associated with the piston to minimize frictional losses and inertial loading. To this end, dual connecting rods are employed with each oval piston. These connecting rods are associated with a crankshaft which has a main bearing for rotatably mounting the shaft to the engine structure between the dual connecting rods associated with each piston. Through this arrangement, smaller crankshaft components, smaller connecting rods and integrally formed connecting rods become practical with attendant reductions in friction loss and excessive inertial forces. Accordingly, it is an object of the present invention to provide an improved internal combustion engine including cylinders and pistons, oval in cross-section. It is another object of the present invention to provide an improved engine drive train for pistons in an internal combustion engine wherein the pistons and cylinders thereof are oval in cross-section. Other and further objects and advantages will appear hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional elevation of an engine incorporating the present invention. FIG. 2 is a cross-sectional side view of the embodiment of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Turning in detail to the drawings, a portion of an engine is disclosed including a head 10 and a cylinder block 12. The engine illustrated forms a portion of a V-4 cylinder motorcycle engine. The cylinder head associated with this particular model includes two spark plugs 14 and four intake and four exhaust valves 16. The bore of each engine cylinder 18 is generally oval in cross-section. In this preferred embodiment, the cylinder cross-section is defined by two straight side sections and two semi-circular end sections. A piston 20 also exhibits an oval cross-section and is designed to move with sliding contact within the bore of the cylinder 18 in conventional fashion. Located below the piston 20, a crankshaft, generally designated 22, is rotatably mounted relative to the cylinder block 12. Connecting rod means extend between each piston 20 and the crankshaft 22. To properly constrain the motion of each piston 20 in its cylinder 18, the connecting rod means includes two connecting rods 24 and 26. For clarity, the connecting rods associated with the piston in front of the piston 20 shown in FIG. 1 are separately labeled 28 and 30. Substantial advantage is provided by the use of dual connecting rods for each piston. By placing the connecting rods 24 and 26 outwardly toward the outer extremeties of the piston 20, maximum angular control of the piston is effected with a minimum of inertial mass. Naturally, bending moments experienced by all associated components are also reduced. The two connecting rods 24 and 26 are pivotally fixed to the piston 20 by means of a wrist pin or piston pin 32. A single wrist pin 32 is employed to hold both of the connecting rods 24 and 26 in place. At the same time, piston bosses 34 and 36 individually locate and support the mounting of the connecting rod 24 while piston bosses 38 and 40 accomplish the same result for the other connecting rod 26. A central space is provided between the bosses 36 and 38 as a means for the reduction of inertial mass. The wrist pin 32 is held in a common bore extending through the piston bosses 34-40 by conventional spring clip means. Furthermore, the bosses 34 and 40 are formed in common with the piston skirt 42. Each connecting rod 24-30 includes a central rod 44, a crank pin journal box 46 and a wrist pin journal box 48. These elements of each connecting rod are integrally formed to minimize inertial mass. The crank pin journal box 46 is associated with the crankshaft 22 about a crank pin thereof with a roller bearing 50 employed for reduced friction. The wrist pin journal box 48 is held in place by the wrist pin 32 and uses a bushing 52 to reduce friction. The crankshaft 22 is a composit structure defined in part by a middle crank portion 54 including two crank pins 56 and 58 and a middle shaft 60. The crank pin 56, the middle shaft 60 and the crank pin 58 are positioned in seriatim and adjacent, being tied together by crank webs 62 and 64. The middle shaft 60 is concentric with the axis of rotation of the crankshaft 22 to receive a main bearing 66. The connecting rods 24-30 are positioned on the crank pins 56 and 58 prior to assembly. The location of the main bearing 66 between these crank pins 56 and 58 thus places the main bearing 66 between connecting rods associated with the same piston. This effectively and greatly reduces the bending moments placed on the crankshaft 22. Outwardly of the middle crankshaft portion 54 are additional crankshaft elements 68 and 70. These additional crankshaft elements 68 and 70 provide additional shaft portions to receive conventionally placed main bearings 72 and 74. Crank webs 76 and 78 receive the outer portions of the crank pins 56 and 58 in holes designed to provide an interference fit with the crank pins. Additional portions of the crankshaft 22, not of immediate concern, include power take-off means 80 and an additional middle crank portion 82 where desired for additional pistons. The crankshaft 22 is held in place as indicated by main bearings 72 and 74 on either side of the middle crank portion 54 and by main bearing 66 located about the middle shaft 60 between crank pins 56 and 58. The main bearing 66 is a roller bearing having rollers 84 and a roller cage 86. The roller cage is split diametrically for assembly. The journal box, generally designated 88 associated with the main bearing 66 includes a first section 90 and a second section 92. Together the first and second sections 90 and 92 define a journal cavity which also acts as the outer race for the rollers 84. The first section 90 is not held by means of fasteners to the crankcase. Rather, the first section 90 is held by fasteners 94 to the second section 92. The second section 92 is in turn fastened to the crankcase 95 portion of the block 12 by means of fasteners 96. The same general construction is applied to the journal box 98 for the main bearing 74. The main bearing 72 may employ either a unitary or split journal box 100 as access is available from the end of the shaft. Assembly of the journal box components with the bearings and crankshaft are accomplished by placing the split roller bearings into position and bolting the first section 90 to the second section 92. This assembly of the crankshaft 22 and the journal boxes 88, 98 and 100 may then be positioned in the bottom portion of the engine and bolted to the engine by means of the fasteners 96. As the connecting rods were placed onto the crankshaft prior to assembly, they would also be associated with the crankshaft 22 during its placement in the engine. Thus, an improved design associated with oval piston and cylinder configurations is here described to particularly enhance the efficiency and reliability of high performance engines. While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein described. The invention, therefore, is not to be restrictive except by the spirit of the appended claims.

An engine employing oval pistons and cylinders with dual connecting rods for each piston. The connecting rods are connected to each piston by a common wrist pin and to a composite crankshaft. The crankshaft includes a main bearing between the connecting rods of each of the pistons. It also includes a middle portion associated with each piston including two crank pins and the shaft therebetween for receipt of the centrally located main bearing.

FIELD OF THE INVENTION [0001] This invention relates to the use of chloro-trifluoropropenes as refrigerants in negative-pressure liquid chillers. The chloro-trifluoropropenes, particularly 1-chloro-3,3,3-trifluoropropene, have high efficiency and unexpectedly high capacity in liquid chiller applications and are useful as more environmentally sustainable refrigerants for such applications, including the replacement of R-123 and R-11. The chloro-trifluoropropenes can be used in new chiller applications or as a top-off or retrofit where the refrigerant is removed from an existing chiller and the chloro-trifluoropropenes of the present invention are added. BACKGROUND OF THE INVENTION [0002] With continued regulatory pressure there is a growing need to identify more environmentally sustainable replacements for refrigerants, heat transfer fluids, foam blowing agents, solvents, and aerosols with lower ozone depleting and global warming potentials. Chlorofluorocarbon (CFC) and hydrochlorofluorocarbons (HCFC), widely used for these applications, are ozone depleting substances and are being phased out in accordance with guidelines of the Montreal Protocol. Hydrofluorocarbons (HFC) are a leading replacement for CFCs and HCFCs in many applications; though they are deemed “friendly” to the ozone layer they still generally possess high global warming potentials. One new class of compounds that has been identified to replace ozone depleting or high global warming substances are halogenated olefins, such as hydrofluoroolefins (HFO) and hydrochlorofluoroolefins (HCFO). In the present invention, it was discovered that chloro-trifluoropropenes are particularly useful refrigerants liquid chiller systems, particularly in negative-pressure chiller systems, such as for the replacement of R-11 and R-123. [0003] With continued regulatory pressure there is a growing need to identify more environmentally sustainable replacements for refrigerants, heat transfer fluids, foam blowing agents, solvents, and aerosols with lower ozone depleting and global warming potentials. Chlorofluorocarbon (CFC) and hydrochlorofluorocarbons (HCFC), widely used for these applications, are ozone depleting substances and are being phased out in accordance with guidelines of the Montreal Protocol. Hydrofluorocarbons (HFC) are a leading replacement for CFCs and HCFCs in many applications; though they are deemed “friendly” to the ozone layer they still generally possess high global warming potentials. One new class of compounds that has been identified to replace ozone depleting or high global warming substances are halogenated olefins, such as hydrofluoroolefins (HFO) and hydrochlorofluoroolefins (HCFO). The HFOs and HCFOs provide the low global warming potential and zero or near zero ozone depletion properties desired. [0004] Chillers are refrigeration machines that cool water, other heat transfer fluids, or process fluids by a vapor-compression (modified reverse-Rankine), absorption, or other thermodynamic cycle. Their most common use is in central systems to air condition large office, commercial, medical, entertainment, residential high-rise, and similar buildings or clusters of buildings. Both large central and interconnected plants, generally with multiple chillers in each, are common for shopping centers, university, medical, and office campuses; military installations; and district cooling systems. The chilled water (or less commonly a brine or other heat-transfer fluid) is piped through the building or buildings to other devices, such as zoned air handlers, that use the cooled water or brine to air condition (cool and dehumidify) occupied or controlled spaces. By their nature, both efficiency and reliability are critical attributes of chillers. Chillers typically range in thermal capacity from approximately 10 kW (3 ton) to exceeding 30 MW (8,500 ton), with a more common range of 300 kW (85 ton) to 14 MW (4,000 ton). Larger systems typically employ multiple chillers, with some installations exceeding 300 MW (85,000 ton) of cooling. Liquid-chilling systems cool water, brine, or other secondary coolant for air conditioning or refrigeration. The system may be either factory-assembled and wired or shipped in sections for erection in the field. The most frequent application is water chilling for air conditioning, although brine cooling for low temperature refrigeration and chilling fluids in industrial processes are also common. [0005] The basic components of a vapor-compression, liquid-chilling system include a compressor, liquid cooler (evaporator), condenser, compressor drive, liquid-refrigerant expansion or flow control device, and control center; it may also include a receiver, economizer, expansion turbine, and/or subcooler. In addition, auxiliary components may be used, such as a lubricant cooler, lubricant separator, lubricant-return device, purge unit, lubricant pump, refrigerant transfer unit, refrigerant vents, and/or additional control valves. [0006] Liquid (usually water) enters the cooler, where it is chilled by liquid refrigerant evaporating at a lower temperature. The refrigerant vaporizes and is drawn into the compressor, which increases the pressure and temperature of the gas so that it may be condensed at the higher temperature in the condenser. The condenser cooling medium is warmed in the process. The condensed liquid refrigerant then flows back to the evaporator through an expansion device. Some of the liquid refrigerant changes to vapor (flashes) as pressure drops between the condenser and the evaporator. Flashing cools the liquid to the saturated temperature at evaporator pressure. It produces no refrigeration in the cooler. The following modifications (sometimes combined for maximum effect) reduce flash gas and increase the net refrigeration per unit of power consumption. [0007] Subcooling. Condensed refrigerant may be subcooled below its saturated condensing temperature in either the subcooler section of a water-cooled condenser or a separate heat exchanger. Subcooling reduces flashing and increases the refrigeration effect in the chiller. [0008] Economizing. This process can occur either in a direct expansion (DX), an expansion turbine, or a flash system. In a DX system, the main liquid refrigerant is usually cooled in the shell of a shell-and-tube heat exchanger, at condensing pressure, from the saturated condensing temperature to within several degrees of the intermediate saturated temperature. Before cooling, a small portion of the liquid flashes and evaporates in the tube side of the heat exchanger to cool the main liquid flow. Although subcooled, the liquid is still at the condensing pressure. [0009] An expansion turbine extracts rotating energy as a portion of the refrigerant vaporizes. As in the DX system, the remaining liquid is supplied to the cooler at intermediate pressure. In a flash system, the entire liquid flow is expanded to intermediate pressure in a vessel that supplies liquid to the cooler at saturated intermediate pressure; however, the liquid is at intermediate pressure. [0010] Flash gas enters the compressor either at an intermediate stage of a multistage centrifugal compressor, at the intermediate stage of an integral two-stage reciprocating compressor, at an intermediate pressure port of a screw compressor, or at the inlet of a high-pressure stage on a multistage reciprocating or screw compressor. [0011] Liquid Injection. Condensed liquid is throttled to the intermediate pressure and injected into the second-stage suction of the compressor to prevent excessively high discharge temperatures and, in the case of centrifugal machines, to reduce noise. For screw compressors, condensed liquid is injected into a port fixed at slightly below discharge pressure to provide lubricant cooling. Basic System [0012] An exemplary refrigeration cycle of a basic liquid chiller system is shown in FIG. 1 . Chilled water enters the cooler at 54° F., for example, and leaves at 44° F. Condenser water leaves a cooling tower at 85° F., enters the condenser, and returns to the cooling tower near 95° F. Condensers may also be cooled by air or evaporation of water. This system, with a single compressor and one refrigerant circuit with a water-cooled condenser, is used extensively to chill water for air conditioning because it is relatively simple and compact. The compressor can be a reciprocating, scroll, screw, or centrifugal compressor. The preferred systems of the present invention are centrifugal liquid chiller systems. [0013] A centrifugal compressor uses rotating elements to accelerate the refrigerant radially, and typically includes an impeller and diffuser housed in a casing. Centrifugal compressors usually take fluid in at an impeller eye, or central inlet of a circulating impeller, and accelerate it radially outwardly. Some static pressure rise occurs in the impeller, but most of the pressure rise occurs in the diffuser section of the casing, where velocity is converted to static pressure. Each impeller-diffuser set is a stage of the compressor. Centrifugal compressors are built with from 1 to 12 or more stages, depending on the final pressure desired and the volume of refrigerant to be handled. [0014] The pressure ratio, or compression ratio, of a compressor is the ratio of absolute discharge pressure to the absolute inlet pressure. Pressure delivered by a centrifugal compressor is practically constant over a relatively wide range of capacities. Therefore, in order to maintain the centrifugal compressor performance while replacing the existing refrigerant, the pressure ratio when using the new refrigerant should be as close as possible to that when using the existing refrigerant. [0015] Unlike a positive displacement compressor, a centrifugal compressor depends entirely on the centrifugal force of the high speed impeller to compress the vapor passing through the impeller. There is no positive displacement, but rather what is called dynamic-compression. [0016] The pressure a centrifugal compressor can develop depends on the tip speed of the impeller. Tip speed is the speed of the impeller measured at its tip and is related to the diameter of the impeller and its revolutions per minute. The capacity of the centrifugal compressor is determined by the size of the passages through the impeller. This makes the size of the compressor more dependent on the pressure required than the capacity. [0017] In order to maintain the centrifugal compressor performance while replacing the existing refrigerant, the predetermined impeller Mach number should be the same as that achieved by the existing refrigerant. Since impeller Mach number is dependent upon the acoustic velocity (speed of sound) of refrigerant, the performance of a compressor can more accurately be maintained by formulating a replacement refrigerant which has the same acoustical velocity as the original refrigerant, or which has an acoustical velocity which theoretically will provide the same impeller Mach number as the existing refrigerant. [0018] An important consideration for compressors, especially when replacing an existing refrigerant with a new one, is the dimensionless specific speed, Ω, defined here as: [0000] Ω = ω  V ( Δ   h ) 3 / 4 [0000] where ω is the angular velocity (rad/s), V is the volume flow rate (m 3 /s) and Δh is the ideal specific work (J/kg) per compressor stage, which can be approximated as: [0000] Δ   h = h 2 - h 1 - ( s 2 - s 1 )   T 2 - T 1 ln  ( T 2 / T 1 ) [0000] where the subscripts 1 and 2 denotes the gas state at the compressor inlet and outlet respectively. H, s, and T are respectively the specific enthalpy, specific entropy, and temperature. Compressors operate with the highest adiabatic efficiency, η, when the Ω has the optimum value for the design. [0019] Because of its high speed operation, a centrifugal compressor is fundamentally a high volume, low pressure machine. A centrifugal compressor works best with a low pressure refrigerant, such as trichlorofluoromethane (CFC-11). When part of the chiller, particularly the evaporator, is operated with at a pressure level below ambient, the chiller is referred to as a negative pressure system. One of the benefits of a low pressure or negative pressure system is low leak rates. Refrigerant leaks are driven by pressure differentials, so lower pressures will result in lower leak rates than high pressure systems. Also, leaks in the system operating at below ambient pressure result in air being sucked into the equipment rather than refrigerant leaking out. While such operation requires a purge device to remove any air and moisture, monitoring the purge operation serves as a warning system for developing leaks. SUMMARY OF THE INVENTION [0020] In the present invention, it was discovered that chloro-trifluoropropenes are particularly useful refrigerants for liquid chiller systems, particularly in negative-pressure chiller systems, such as for the replacement of R-11 and R-123. The chloro-trifluoropropenes of the present invention were discovered to provide operating conditions comparable to current chiller refrigerants and also to be compatible with current chiller lubricants. The chloro-trifluoropropenes of the present invention are preferrably 1-chloro-3,3,3-trifluoropropene and/or 2-chloro-3,3,3-trifluoropropene, and more preferrably trans-1-chloro-3,3,3-trifluoropropene. BRIEF DESCRIPTION OF THE DRAWINGS [0021] FIG. 1 is a schematic of a typical chiller system. [0022] FIG. 2 is a chart of COP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of −10° C. [0023] FIG. 3 is a chart of CAP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of −10° C. [0024] FIG. 4 is a chart of COP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of 0° C. [0025] FIG. 5 is a chart of CAP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of 0° C. [0026] FIG. 6 is a chart of COP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of 5° C. [0027] FIG. 7 is a chart of CAP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of 5° C. [0028] FIG. 8 is a chart of COP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of 10° C. [0029] FIG. 9 is a chart of CAP for R-123, R-1233zd, and R-1234ze at an evaporator temperature of 10° C. DETAILED DESCRIPTION OF THE INVENTION [0030] The chloro-trifluoropropene refrigerant composition of the present invention can be added to a new chiller system or be employed in a method of topping-off or retrofitting an existing chiller system. The chloro-trifluoropropene refrigerant composition of the present invention is particularly useful in chillers, preferably those operated at negative pressure, using centrifugal compressors and flooded evaporators. The retrofit method, comprises the steps of removing the existing refrigerant from the chiller system while optionally retaining a substantial portion of the lubricant in said system; and introducing to said system a composition comprising a chloro-trifluoropropene refrigerant of the present invention which is miscible with the lubricant present in the system without the need for addition surfactants and/or solubilizing agents. In topping-off an existing chiller system, the chloro-trifluoropropene refrigerant of the present invention is added to top-off a refrigerant charge or as a partial replacement either to replace refrigerant lost or after removing part of the existing refrigerant and then adding the chloro-trifluoropropene refrigerant of the present invention. The preferred chloro-trifluoropropene refrigerant of the present invention is preferrably 1-chloro-3,3,3-trifluoropropene and/or 2-chloro-3,3,3-trifluoropropene, and more preferrably trans-1-chloro-3,3,3-trifluoropropene. [0031] As used herein, the term “substantial portion” refers generally to a quantity of lubricant which is at least about 50% (all percentages herein are by weight unless indicated otherwise) of the quantity of lubricant contained in the refrigeration system prior to removal of the prior refrigerant. Preferably, the substantial portion of lubricant in the system according to the present invention is a quantity of at least about 60% of the lubricant contained originally in the refrigeration system, and more preferably a quantity of at least about 70%. [0032] Any of a wide range of known methods can be used to remove prior refrigerants from a chiller system while removing less than a major portion of the lubricant contained in the system. According to preferred embodiments, the lubricant is a hydrocarbon-based lubricant and the removal step results in at least about 90%, and even more preferably at least about 95%, of said lubricant remaining in the system. The removal step may readily be performed by pumping the original refrigerants in the gaseous state out of a refrigeration system containing liquid state lubricants, because refrigerants are quite volatile relative to traditional hydrocarbon-based lubricants. The boiling point of refrigerants are generally under 30° C. whereas the boiling point of mineral oils are generally over 200° C. Such removal can be achieved in any of a number of ways known in the art, including, the use of a refrigerant recovery system. Alternatively, a cooled, evacuated refrigerant container can be attached to the low pressure side of a refrigeration system such that the gaseous prior refrigerant is drawn into the evacuated container and removed. Moreover, a compressor may be attached to a refrigeration system to pump the prior refrigerant from the system to an evacuated container. In light of the above disclosure, those of ordinary skill in the art will be readily able to remove the prior refrigerants from chiller systems and to provide a refrigeration system comprising a chamber having therein a hydrocarbon-based lubricant and a chloro-trifluoropropene refrigerant according to the present invention. [0033] The method of the present invention comprises introducing to a chiller system, a composition comprising at least one chloro-trifluoropropene refrigerant of the present invention miscible with the lubricant present in the system. The lubricants in the chiller system can be hydrocarbon lubricating oils, oxygenated lubrication oils or mixtures thereof [0034] In addition to the chloro-trifluoropropene refrigerant of the present invention, the composition introduced into the system can include an additional refrigerant selected from hydrofluorcarbons, hydrochlorofluorocarbons, chlorofluorocarbons, hydrochloroolefins, hydrofluoroethers, fluoroketones, hydrocarbons, ammonia, or mixtures thereof, preferably where the additional refrigerant is non-flammable and/or the resulting refrigerant composition is non-flammable [0035] The hydrofluorocarbon can be selected from difluoromethane (HFC-32), 1-fluoroethane (HFC-161), 1,1-difluoroethane (HFC-152a), 1,2-difluoroethane (HFC-152), 1,1,1-trifluoroethane (HFC-143a), 1,1,2-trifluoroethane (HFC-143), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), pentafluoroethane (HFC-125), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,2,2,3-pentafluoropropane (HFC-245ca), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,3,3-pentafluorbutane (HFC-365mfc), 1,1,1,2,3,4,4,5,5,5-decafluoropropane (HFC-4310) and mixtures thereof. [0036] The hydrochlorofluorocarbon can be selected from 1,1-dichloro-2,2,2-trifluoroethane (R-123), 1-chloro-1,2,2,2-tetrafluoroethane (R-124), 1,1-dichloro-1-fluoroethane (R-141b). 1-chloro-1,1-difluoroethane (R-142b) and mixtures thereof, preferably R-123. [0037] The chlorofluorcarbons can be trichlorofluoromethane (R-11), dichlorodifluoromethane (R-12), 1,1,2-trichloro-1,2,2-trifluoroethane (R-113), 1,2-dichloro-1,1,2,2-tetrafluoroethane (R-114), chloropentafluoroethane (R-115), or mixtures thereof, preferably R-11. [0038] Exemplary hydrofluoroethers include 1,1,1,2,2,3,3-heptafluoro-3-methoxy-propane, 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxy-butane, or mixtures thereof. An exemplary fluoroketone is 1,1,1,2,2,4,5,5,5-nonafluoro-4(trifluoromethyl)-3-pentanone. [0039] The hydrofluoroolefins can be a C3 to C5 hydrofluoroolefin containing at least one fluorine atom, at least one hydrogen atom and at least one alkene linkage. Exemplary hydrofluoroolefins include 3,3,3-trifluoropropene (HFO-1234zf), E-1,3,3,3-tetrafluoropropene, (E-HFO-1234ze), Z-1,3,3,3-tetrafluoropropene (Z—HFO-1234ze), 2,3,3,3-tetrafluoropropene (HFO-1234yf), E-1,2,3,3,-pentafluoropropene (E-HFO-1255ye), Z-1,2,3,3,3-pentafluoropropene (Z—HFO-125ye), E-1,1,1,3,3,3-hexafluorobut-2-ene (E-HFO-1336mzz), Z-1,1,1,3,3,3-hexafluorobut-2-ene (Z—HFO-1336mzz), 1,1,1,4,4,5,5,5-octafluoropent-2-ene (HFO-1438mzz) or mixtures thereof. [0040] An exemplary hydrochloroolefin is trans-1,2-dichloroethylene. [0041] The hydrocarbons can C3 to C7 alkanes, preferably butanes, pentanes, or mixtures thereof, more preferably n-pentane, isopentane, cyclopentane, or mixtures thereof. [0042] Current chiller lubricants include, but are not limted to, mineral oils, polyol ester oils, polyalklylene glycol oils, polyvinyl ether oils, poly(alphaolefin) oils, alkyl benzene oils and mixtures thereof. Preferred chiller lubricants are mineral oils. The chloro-trifluopropenes of the present invention were found to be miscible with mineral oils as well as other chiller lubricants. [0043] In addition to the chloro-trifluoropropene refrigerant miscible with the lubricant of the present invention, the composition introduced into the system can include other additives or materials of the type used in refrigerant compositions to enhance their performance in refrigeration systems. For example, the composition can include extreme pressure and antiwear additives, oxidation stability improvers, corrosion inhibitors, viscosity index improvers, pour and floc point depressants, antifoaming agents, viscosity adjusters, UV dyes, tracers, and the like. [0044] The following non-limiting examples are hereby provided as reference: EXAMPLES Liquid Chiller Performance Data [0045] The performance of the refrigerants R-123 (1,1-dichloro-2,2,2-trifluoroethane), R-1233zd (1-chloro-3,3,3-trifluoropropene, predominantly trans-isomer), and R-1234yf (2,3,3,3-tetrafluoropropene) in a liquid chiller application were evaluated in the following examples. In each example, data is provided at a given evaporator temperature and at multiple condenser temperatures, ranging from 30° C. to 55° C. The isentropic efficiency in each case was 0.7. Data for R-123 and R-1234yf are provided as comparative examples. [0000] In the following examples, the following nomenclature is used: [0046] Condenser discharge temperature: T cond [0047] Condenser pressure: P cond [0048] Evaporator pressure: P evap [0049] Pressure difference between condenser and evaporator: P diff [0050] Pressure ratio of the condenser to the evaporator: P ratio [0051] Coefficient of Performance (energy efficiency): COP [0052] Capacity: CAP Example 1 [0053] In this example, the following conditions were used: [0054] Evaporator temperature=−10° C. Compressor inlet temperature=−5° C. Isentropic efficiency=0.7. The results are tabulated in Table 1. [0055] FIGS. 2 and 3 show the COP and CAP of R-1233zd and R-1234ze relative to R-123. [0000] TABLE 1 T evap −10° C. Internal heat exchanger inlet compressor −5° C. isentropic efficiency 0.7 Tcond evap P cond P P diff P ratio CAP (° C.) (kPa) (kPa) (kPa) (p/p) (KJ/m 3 ) COP R-1234yf 30.0 219 772 554 3.53 1456 3.6 35.0 219 882 663 4.03 1372 3.1 40.0 219 1003 785 4.58 1287 2.7 45.0 219 1137 918 5.19 1200 2.3 50.0 219 1283 1064 5.86 1111 2.0 55.0 219 1443 1224 6.59 1019 1.7 R-1233zd 30.0 28 155 127 5.51 280 3.9 35.0 28 184 156 6.54 269 3.4 40.0 28 217 189 7.71 257 2.9 45.0 28 254 226 9.04 245 2.6 50.0 28 296 268 10.52 233 2.3 55.0 28 343 314 12.18 222 2.1 R-123 30.0 20 110 90 5.44 206 4.0 35.0 20 131 111 6.47 199 3.5 40.0 20 155 135 7.66 192 3.1 45.0 20 182 162 9.00 184 2.7 50.0 20 213 192 10.52 177 2.4 55.0 20 247 227 12.23 169 2.2 Example 2 [0056] In this example, the following conditions were used: [0057] Evaporator temperature=0° C. Compressor inlet temperature=5° C. Isentropic efficiency=0.7. The results are tabulated in Table 2. [0058] FIGS. 4 and 5 show the COP and CAP of R-1233zd and R-1234ze relative to R-123. [0000] TABLE 2 T evap 0° C. Internal heat exchanger inlet compressor 5° C. isentropic efficiency 0.7 Tcond evap P cond P P diff P ratio CAP (° C.) (kPa) (kPa) (kPa) (p/p) (KJ/m 3 ) COP R-1234yf 30.0 312 772 461 2.48 2152 5.3 35.0 312 882 570 2.83 2035 4.4 40.0 312 1003 691 3.22 1915 3.7 45.0 312 1137 825 3.64 1793 3.1 50.0 312 1283 971 4.11 1668 2.7 55.0 312 1443 1131 4.62 1540 2.3 R-1233zd 30.0 46 155 109 3.37 463 5.6 35.0 46 184 138 4.00 444 4.7 40.0 46 217 171 4.72 426 4.0 45.0 46 254 208 5.53 407 3.5 50.0 46 296 250 6.43 389 3.0 55.0 46 343 297 7.45 370 2.7 R-123 30.0 33 110 77 3.36 337 5.7 35.0 33 131 98 4.00 325 4.8 40.0 33 155 122 4.74 314 4.1 45.0 33 182 149 5.57 302 3.6 50.0 33 213 180 6.51 290 3.1 55.0 33 247 215 7.56 279 2.8 Example 3 [0059] In this example, the following conditions were used: [0060] Evaporator temperature=5° C. Compressor inlet temperature=10° C. Isentropic efficiency=0.7. The results are tabulated in Table 3. [0061] FIGS. 6 and 7 show the COP and CAP of R-1233zd and R-1234ze relative to R-123. [0000] TABLE 3 T evap 5° C. Internal heat exchanger inlet compressor 10° C. isentropic efficiency 0.7 Tcond evap P cond P P diff T-out CAP (° C.) (kPa) (kPa) (kPa) comp (KJ/m 3 ) COP R-1234yf 30.0 368 772 404 39 2610 6.7 35.0 368 882 514 45 2472 5.4 40.0 368 1003 635 51 2332 4.4 45.0 368 1136 768 56 2188 3.7 R-1233zd 30.0 58 154 96 44 585 7.0 35.0 58 183 125 50 562 5.7 40.0 58 216 158 55 539 4.8 45.0 58 254 196 61 516 4.1 R-123 30.0 41 110 69 44 423 7.2 35.0 41 131 90 50 409 5.8 40.0 41 155 114 56 395 4.9 45.0 41 182 141 61 381 4.2 Example 4 [0062] In this example, the following conditions were used: [0063] Evaporator temperature=10° C. Compressor inlet temperature=15° C. Isentropic efficiency=0.7. The results are tabulated in Table 4. [0064] FIGS. 8 and 9 show the COP and CAP of R-1233zd and R-1234ze relative to R-123. [0000] TABLE 4 T evap 10° C. Internal heat exchanger inlet compressor 15° C. isentropic efficiency 0.7 Tcond evap P cond P P diff P ratio CAP (° C.) (kPa) (kPa) (kPa) (p/p) (KJ/m 3 ) COP R-1234yf 30.0 432 772 340 1.79 3097 8.7 35.0 432 882 450 2.04 2936 6.7 40.0 432 1003 571 2.32 2773 5.4 45.0 432 1137 705 2.63 2606 4.4 50.0 432 1283 851 2.97 2435 3.7 55.0 432 1443 1011 3.34 2258 3.1 R-1233zd 30.0 72 155 83 2.16 731 9.1 35.0 72 184 112 2.57 703 7.1 40.0 72 217 145 3.03 674 5.8 45.0 72 254 182 3.55 646 4.8 50.0 72 296 224 4.13 618 4.1 55.0 72 343 271 4.78 591 3.6 R-123 30.0 51 110 59 2.17 528 9.3 35.0 51 131 80 2.58 510 7.3 40.0 51 155 104 3.05 493 5.9 45.0 51 182 131 3.59 475 5.0 50.0 51 213 162 4.19 458 4.3 55.0 51 247 196 4.88 440 3.7 [0065] Representative data from Tables 1 through 4 is charted in FIGS. 2 through 9 . [0066] In all of these examples, the efficiency of R-1233zd was very close to that of R-123, being within a few percent of the efficiency of R-123. In contrast, the efficiency of R-1234yf was significantly lower than that of R-1233zd and R-123, being from 6.4% lower to over 20% lower than that of R-123. It was also unexpectedly discovered that the capacity of R-1233zd was from 30% to 40% greater than that of R-123. [0067] It is also shown that for R-1233zd and for R-123 the system is operated as a negative-pressure system, where the pressure in the evaporator is below ambient. For R-1234yf the entire system is operated at positive-pressure. [0068] R-1233zd was found to provide a close match to operating pressures, pressure ratio, and pressure difference of R-123 and can be used as a more environmentally acceptable replacement. Example 5 Acoustic Velocity [0069] The acoustic velocity for R-11, R-123, R-134a, R-1233zd and R-1234yf were determined at 40° C. and 1 bar. The acoustic velocity of R-1233zd is close to that of R-11 and closer to that of R-123 than either R-134a or R-1234yf. [0000] TABLE 5 Acoustic Velocity of Refrigerants Conditions: 40° C. and 1 bar. Acoustic Velocity Refrigerant (m/s) R123 131.9 R-11 142.0 R-1233zd 143.7 R-1234yf 155.6 R-134a 165.7 Example 6 Dimensionless Specific Speed [0070] The performance of R-123, R-1233zd, and R-1234yf in a liquid chiller was determined as in example 2, with a compressor inlet temperature at 5° C. and a condenser temperature at 40° C. The results are shown in Table 6, which also gives the ratio of the dimensionless specific speed, Ω, of the refrigerant to that of R-123 (Ω 123 ), assuming the chillers are operated to deliver the same capacity of cooling. R-1233zd was found to be a good replacement for R-123 as compared to R-1234ze. [0000] TABLE 6 Dimensionless Specific Speed of Refrigerants at Equivalent Cooling Capacity Evaporator Temp: 5° C. Condenser Temp: 40° C. P Temp Refrigerant Compressor (bar) (° C.) Ω/Ω 123 R123 inlet 0.33 5 1 outlet 1.55 58 R-1233zd inlet 0.46 5 0.76 outlet 2.17 58 R-1234yf inlet 3.12 5 0.44 outlet 10.03 52 [0071] These results show that R-1233, particularly R-1233zd is useful as a refrigerant for liquid chillers, particularly negative-pressure chillers, and especially in large systems due to the efficiency benefits of R-1233zd over R-1234yf or similar refrigerants.

This invention relates to the use of chloro-trifluoropropenes as refrigerants in negative-pressure liquid chillers and methods of replacing an existing refrigerant in a chiller with chloro-trifluoropropenes. The chloro-trifluoropropenes, particularly 1-chloro-3,3,3-trifluoropropene, have high efficiency and unexpectedly high capacity in liquid chiller applications and are useful as more environmentally sustainable refrigerants for such applications, including the replacement of R-123 and R-11.

BACKGROUND OF THE INVENTION [0001] The present invention relates to an improved air-suspension system for a vehicle, especially a closed or partly closed system. [0002] An air-suspension system of the general type under consideration is described in DE 199 59 556 C1. [0003] In such conventional air-suspension systems, a compressed-air delivery device such as a compressor is used, on the one hand, to pump air as needed from a compressed-air accumulator into the air-suspension bellows, and, on the other hand, to pump air as needed from the air-suspension bellows back into the compressed-air accumulator. To change over between these two compressed-air delivery directions, a changeover-valve device is provided between the compressed-air accumulator and air-suspension bellows on the one side and the compressed-air delivery device on the other side. In the air-suspension system described in DE 199 59 556 C1, the changeover-valve device can comprise, for example, two electrically actuatable 3/2-way valves designed as directly controlled solenoid valves. [0004] In an air-suspension system, it is desired that the air-suspension bellows can be filled and emptied as rapidly as possible. This necessitates valve devices, and, in particular, also a changeover-valve device with large nominal width, or, in other words, with large passage cross section. Such valve devices have relatively large size and thus are relatively heavy and expensive. SUMMARY OF THE INVENTION [0005] Generally speaking, in accordance with the present invention, an improved vehicle air-suspension system is provided that permits rapid filling and emptying of the air-suspension bellows with comparatively inexpensive and compact construction. [0006] The present invention has the advantage that the changeover-valve device, and, thus, also the air-suspension system, can be made lightweight and at a more favorable price than is possible with conventional solutions. A further advantage is that only a single electromagnet is necessary for electrical actuation. Moreover, it can have relatively small dimensions. As a result, the electrical energy consumption during actuation of the electromagnet is distinctly reduced compared with conventional solutions. In addition, only a single control connection to an electronic control unit is needed for activation of the changeover-valve device. [0007] Still other objects and advantages of the present invention will in part be obvious and will in part be apparent from the specification. [0008] The present invention accordingly comprises the features of construction, combination of elements, and arrangements of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0009] The present invention will be described in more detail hereinafter and further advantages will be pointed out on the basis of practical examples with reference to the accompanying drawings, wherein: [0010] FIG. 1 is a schematic diagram of a partly closed air-suspension system according to one embodiment of the present invention; [0011] FIG. 2 shows a compressed-air delivery device for use in the inventive air-suspension system according to FIG. 1 ; [0012] FIG. 3 shows a 4/2-way changeover valve in a first operating position in accordance with an embodiment of the present invention; [0013] FIG. 4 shows the 4/2-way changeover valve in a second operating position in accordance with an embodiment of the present invention; [0014] FIG. 5 shows the 4/2-way valve in a third operating position in accordance with an embodiment of the present invention; [0015] FIGS. 6 to 9 show further embodiments of an air-discharge/dryer device for use in the inventive air-suspension system according to FIG. 1 ; [0016] FIGS. 10 to 12 show further embodiments of a changeover-valve device for use in the inventive air-suspension system according to FIG. 1 ; [0017] FIGS. 13 and 14 show a 4/2-way changeover-valve device in different valve positions in accordance with an embodiment of the present invention. [0018] In the figures, like reference symbols are used for parts that correspond to one another. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0019] The function of an air-suspension system for a vehicle is to adjust and control, via leveling means, the level height of the vehicle body relative to the vehicle axles and thus indirectly relative to the roadway. For this purpose such a leveling means is preferably disposed on each wheel of a vehicle, and air-suspension bellows are preferably used as leveling means. By filling or venting the individual air-suspension bellows, any desired level heights of the vehicle body can be adjusted within an adjustment range provided for the purpose. Such air-suspension systems are preferably operated with compressed air as the pressurized medium. [0020] In air-suspension systems constructed and arranged as open systems, compressed air is sucked in as necessary from the surroundings, or, in other words, from the atmosphere, and pumped into the air-suspension bellows or into a compressed-air accumulator, or, in other words, a reservoir tank. The compressed-air accumulator, however, is not absolutely necessary and, depending on requirements, may even be left out. During venting of the air-suspension bellows, the compressed-air is always discharged directly to the atmosphere. Return delivery of compressed air from the air-suspension bellows into the compressed-air accumulator is not provided in such cases. The open system is of relatively simple design, and operates with relatively few components. Such air-suspension systems have been used for many years in commercial vehicles such as trucks and buses and also in passenger cars. [0021] In contrast, a closed system always contains a compressed-air accumulator, which—at least theoretically—is filled one time with compressed air, for example, during manufacture of the air-suspension system. The closed system has no kind of communication with the atmosphere—at least theoretically. During operation as designed, the compressed air is delivered forward and back as needed by a compressed-air delivery device, from the compressed-air accumulator to the air-suspension bellows or from the air-suspension bellows to the compressed-air accumulator. Compared with an open system, this has the advantage that the change of pressure level to be established during air delivery by the compressed-air delivery device, such as a compressor, is usually smaller, since the pressure of the compressed air to be delivered is usually at a certain level, which is relatively high compared with atmospheric pressure. As a result, the energy consumption of such a closed system is smaller. In addition, the compressed-air delivery device can be designed for smaller power consumption. Other advantages are that the compressed-air delivery device can be operated with a shorter “On” time and that it develops relatively little internal heat. [0022] In practice, such closed systems are not able to function continuously because they lose compressed air, for example due to leaks in the air-suspension bellows which are made of elastic material. It has therefore been proposed that partly closed systems be used in which a compressed-air accumulator is also provided and in which, as long as sufficient compressed air is present in the system, the compressed air is delivered forward and back between the compressed-air accumulator and the air-suspension bellows, just as in the closed system. In addition, communication with the atmosphere is provided, so that the system can be filled with compressed air, for example in the event of pressure losses or large temperature fluctuations, and air can be sucked in from the atmosphere. To avoid overpressure conditions, it is additionally standard practice to provide an air-discharge device for venting excess pressure to the atmosphere. [0023] In such a partly closed system, therefore, some air exchange, albeit of limited extent, takes place with the atmosphere. As a result, the partly closed system not only is practical but also it can largely exploit the advantages of a closed system. Such an air-suspension system designed as a partly closed system is preferably provided with the following functional units: a compressed-air delivery device, which preferably is designed as a compressor and, for example, can be driven by an electric motor, a compressed-air accumulator for storage of compressed air at a specified pressure level, air-suspension bellows, an air-intake device, an air-discharge device, and an air-dryer device. [0030] The foregoing functional units can be placed in communication with one another via actuatable valve devices, especially electrically actuatable valve devices, in such a way that “increase air quantity”, “hold air quantity” and “decrease air quantity” functions can be activated for the air-suspension bellows. A desired level height can then be adjusted for the duration of an “increase air quantity” or “decrease air quantity” process. Such an air-suspension system is preferably controlled by an electronic control unit. [0031] FIG. 1 illustrates a partly closed air-suspension system according to a preferred embodiment of the present invention. The compressed-air delivery device is illustrated in block ( 1 ), which is outlined in broken lines. The air-discharge device in combination with the air-dryer device, referred to hereinafter as air-discharge/dryer device ( 2 ), is illustrated in block ( 2 ), which is outlined in broken lines. The air-intake device is illustrated in block ( 4 ), which is outlined by broken lines. The compressed-air accumulator ( 9 ) as well as the air-suspension bellows ( 64 , 65 , 66 , 67 ) are also illustrated. In addition, displacement sensors ( 68 , 69 , 70 , 71 ) are allocated to air-suspension bellows ( 64 , 65 , 66 , 67 ). Via electrical lines, displacement sensors ( 68 , 69 , 70 , 71 ) respectively transmit, to an electronic control unit ( 5 ), an electrical signal representative of the level height of the vehicle body in the region of that air-suspension bellows to which they are allocated. [0032] In a further block ( 3 ), which is also outlined in broken lines, there is illustrated a changeover-valve device which is used for control of the compressed-air flow direction during delivery of compressed air forward or back between compressed-air accumulator ( 9 ) and air-suspension bellows ( 64 , 65 , 66 , 67 ). By switching changeover-valve device ( 3 ) to a first valve position, compressed-air accumulator ( 9 ), acting as a compressed-air source, can be placed in communication alternately with compressed-air bellows ( 64 , 65 , 66 , 67 ). In a second valve position of changeover valve ( 3 ), air-suspension bellows ( 64 , 65 , 66 , 67 ), acting as the compressed-air source, can be placed in communication with compressed-air accumulator ( 9 ). Accordingly, the “increase air quantity” function can be activated relative to air-suspension bellows ( 64 , 65 , 66 , 67 ) in the first valve position, while the “decrease air quantity” function can be activated in the second valve position. [0033] Via a shutoff valve ( 8 ), designed as an electromagnetically actuatable 2/2-way valve and also referred to hereinafter as the accumulator valve, compressed-air accumulator ( 9 ) illustrated in FIG. 1 is placed in communication with a port ( 318 ) of changeover-valve device ( 3 ). Via respective shutoff valves ( 60 , 61 , 62 , 63 ) disposed upstream from each air-suspension bellows and also referred to hereinafter as bellows valves, as well as via a common compressed-air line ( 72 ), air-suspension bellows ( 64 , 65 , 66 , 67 ) are placed in communication with a further port ( 316 ) of changeover-valve device ( 3 ). Preferably, bellows valves ( 60 , 61 , 62 , 63 ) are also designed as electromagnetically actuatable 2/2-way valves. Check valves ( 51 , 52 ) connected via their inlet sides are provided at a further port ( 317 ) of changeover-valve device ( 3 ). On the outlet side, check valve ( 51 ) is in communication with air intake device ( 4 ) as well as with a suction port ( 105 ) of compressed-air delivery device ( 1 ). An outlet port ( 106 ) of compressed-air delivery device ( 1 ) is in communication with an air inlet of air-discharge/dryer device ( 2 ). A check valve ( 50 ) is disposed at one outlet of air-discharge/dryer device ( 2 ). Check valves ( 50 , 52 ) are in communication via their outlet sides with a further port ( 315 ) of changeover-valve device ( 3 ). [0034] In the air-suspension system configuration illustrated in FIG. 1 , there is disposed, at the outlet side of check valve ( 50 ), a pressure sensor ( 7 ) that measures the pressure present there and transmits an electrical signal representative of that pressure to electronic control unit ( 5 ). If necessary, pressure sensor ( 7 ) can be provided as an option or can even be omitted to achieve more favorable manufacturing costs for the air-suspension system, as will be explained in more detail hereinafter. [0035] There is also provided an electric motor ( 6 ) that can be turned on via an electrical signal from electronic control unit ( 5 ). Via a drive shaft ( 14 ), electric motor ( 6 ) drives a piston machine ( 12 ) provided in compressed-air delivery device ( 1 ). [0036] Electronic control unit ( 5 ) is preferably used for control of all functions of the air-suspension system. For this purpose, control unit ( 5 ) is connected via electrical lines to an electric actuating device of changeover-valve device ( 3 ), to shutoff valves ( 8 , 60 , 61 , 62 , 63 ), to optional pressure sensor ( 7 ), to displacement sensors ( 68 , 69 , 70 , 71 ) and to electric motor ( 6 ). [0037] Compressed-air delivery device ( 1 ) is provided with the functional units explained in greater detail hereinafter. A piston machine ( 12 ) is used to deliver air from suction port ( 105 ) to outlet port ( 106 ) of compressed-air delivery device ( 1 ). Piston machine ( 12 ) can be designed as any suitable conventional piston compressor, even, for example, a rocking-piston compressor. As mentioned, piston machine ( 12 ) can be driven via a drive shaft ( 14 ). On the intake side of compressed-air delivery device ( 1 ) there is disposed a suction valve ( 11 ) designed as a check valve. On the outlet side of compressed-air delivery device ( 1 ) there is disposed an outlet valve ( 13 ), also designed as a check valve. The delivery direction of compressed-air delivery device ( 1 ) is determined by check valves ( 11 , 13 ). [0038] Hereinafter, not only the suction valve ( 11 ) but also all parts of the air-suspension system in direct or indirect pneumatic communication with suction port ( 105 ), from suction valve ( 11 ) to port ( 317 ) of changeover-valve device ( 3 ), will be regarded as allocated to the intake side of compressed-air delivery device ( 1 ). In the practical example according to FIG. 1 , these are parts ( 10 , 11 , 40 , 41 , 42 , 51 , 105 , 317 ) as well as the inlet of check valve ( 52 ). Also hereinafter, not only the outlet valve ( 13 ) but also all parts of the air-suspension system in direct or indirect pneumatic communication with outlet port ( 106 ), from outlet valve ( 13 ) to port ( 315 ) of changeover-valve device ( 3 ), will be regarded as allocated to the outlet side of compressed-air delivery device ( 1 ). In the practical example according to FIG. 1 , these are parts ( 2 , 7 , 13 , 50 , 106 , 315 ) as well as the outlet of check valve ( 52 ). [0039] As depicted in FIG. 1 , the volume ( 10 ) illustrated with an accumulator symbol on the intake side of compressed-air delivery device ( 1 ) symbolically represents all volumes present on the intake side of compressed-air delivery device ( 1 ), such as the volume of the crankcase of piston machine ( 12 ) or even the compressed-air lines connected to the intake side of compressed-air delivery device ( 1 ). Volumes present on the outlet side of compressed-air delivery device ( 1 ) are represented collectively by a volume ( 15 ), which will be described in more detail hereinafter, and which is illustrated in air-discharge/dryer device ( 2 ) in FIG. 1 . [0040] A practical example of such a compressed-air delivery device ( 1 ) is illustrated in FIG. 2 in the form of a piston compressor. The piston machine ( 12 ) is provided inside its case with a drive shaft ( 14 ), which is mechanically connected to a piston ( 17 ) via a connecting member ( 104 ), a revolute joint ( 107 ), a connecting rod ( 16 ) and a further revolute joint ( 18 ). In response to rotation of drive shaft ( 14 ), piston ( 17 ) executes an upward and downward movement. Piston ( 17 ) is equipped with a circumferential seal ( 100 ), which seals a pressure space ( 108 ) provided above the piston from a suction space ( 110 ) provided in the crankcase of compressor ( 12 ). On the top end of piston ( 17 ) there is disposed suction valve ( 11 ), which for design reasons is preferably formed as a thin plate, which is fastened to piston ( 17 ), for example by means of a screw ( 19 ). During upward movement of piston ( 17 ), suction valve ( 11 ) functions to seal pressure space ( 108 ) from an intake opening ( 101 ) that passes through piston ( 17 ). [0041] Above pressure space ( 108 ) there is provided an outlet space ( 150 ). In outlet space ( 150 ) there is provided outlet valve ( 13 ), which for design reasons is preferably formed as a thin plate, which is fastened, for example by means of a screw ( 103 ), to the underside of outlet space ( 150 ). During downward movement of piston ( 17 ), outlet valve ( 13 ) seals outlet space ( 150 ) from an outlet duct ( 102 ) as well as from pressure space ( 108 ). [0042] During a downward stroke of piston ( 17 ), the air sucked in via suction port ( 105 ) flows through intake duct ( 101 ) and valve ( 11 ), which is open at the time, into pressure space ( 108 ), which at the time is shut off from outlet space ( 150 ) by means of valve ( 13 ). During an upward stroke of piston ( 17 ), suction valve ( 11 ) closes, whereby the air present in pressure space ( 108 ) is pressed through outlet duct ( 102 ) and outlet valve ( 13 ), which is open at the time, into outlet space ( 150 ). From outlet space ( 150 ), the compressed air present there can then flow via outlet port ( 106 ) into downstream air-discharge/dryer device ( 2 ). [0043] According to FIG. 1 , air-discharge/dryer device ( 2 ) is provided in an advantageous configuration with a compressed-air-controlled 4/3-way valve ( 20 ) as well as with an air dryer ( 21 ). Between 4/3-way valve ( 20 ) and air dryer ( 21 ) there is illustrated volume ( 15 ), represented by an accumulator symbol, which represents the volumes due to air-discharge/dryer device ( 2 ), especially that due to the air-dryer cartridge. The volumes present on the outlet side of compressed-air delivery device ( 1 ) are also included in volume ( 15 ). [0044] In the valve position of valve ( 20 ) illustrated in FIG. 1 , the compressed air discharged by compressed-air delivery device ( 1 ) flows via a compressed-air line ( 22 ) into valve ( 20 ) at a port ( 223 ), out of valve ( 20 ) at a further port ( 224 ) and into a compressed-air line ( 24 ), from there through air dryer ( 21 ) and from there via check valve ( 50 ) to changeover-valve device ( 3 ). Via a compressed-air line ( 25 ), the outlet side of air dryer ( 21 ) is additionally provided with communication back to a further port ( 225 ) of valve ( 20 ), which is shut off in the valve position illustrated in FIG. 1 . A further port ( 215 ) of valve ( 20 ) is used as the vent port of the air-suspension system; it is in communication with the atmosphere. [0045] Via a compressed-air line ( 23 ), port ( 223 ) of valve ( 20 ), which is in communication with compressed-air delivery device ( 1 ), is in communication with a compressed-air-actuated control port of valve ( 20 ). When the pressure at the control port rises appropriately, valve ( 20 ) can be changed over from the valve position illustrated in FIG. 1 to a second and a third valve position. [0046] The connecting duct between ports ( 223 , 224 ) of valve ( 20 ) still has relatively large passage cross section in the first valve position, but in the second valve position it is changed over to a throttling position with greatly reduced passage cross section. Compressed-air line ( 25 ) continues to be shut off in the second valve position. As the pressure at the control port rises further, the third valve position is finally established. The throttling position with greatly reduced passage cross section is again provided between ports ( 223 , 224 ) of valve ( 20 ). Compressed-air line ( 25 ) is then in communication with the compressed-air outlet at port ( 215 ), or, in other words with the atmosphere, and so compressed air can be discharged to the atmosphere. In this context, valve ( 20 ) also functions as an overpressure safety valve, or, in other words, as a safeguard against undesirably high pressure values in the air-suspension system, as will also be described in greater detail hereinafter. [0047] Because of the throttling effect of valve ( 20 ) in the second and third valve positions, the compressed air expands on its way from compressed-air line ( 22 ) to compressed-air line ( 24 ), and thus arrives in expanded condition or, in other words, at a lower pressure level in air dryer ( 21 ), after which it can be discharged to the atmosphere when the third valve position of valve ( 20 ) is reached. Because of the expansion of the compressed air as a result of the throttling effect, an improved regeneration effect of the dryer granules present in air dryer ( 21 ) is achieved. Thus a relatively good drying effect is achieved with relatively little compressed-air consumption. [0048] In contrast to conventional air-suspension systems, the air-dryer device in the air-suspension system according to embodiments of the present invention described herein is advantageously disposed such that compressed air always flows through it in the same flow direction both in normal operation of the air-suspension system and in regeneration operation, or, in other words, during extraction of moisture from the dryer granules. This has the advantage that air dryer ( 21 ) can be mounted permanently at the outlet side of compressed-air delivery device ( 1 ). In particular, it can be disposed in relatively close spatial proximity to the compressed-air delivery device, and so air preheated by the compressed-air delivery device can be passed through it in any mode of operation. Because of the spatially compact arrangement next to the compressed-air delivery device, the heated compressed air can reach air dryer ( 21 ) with a relatively small temperature drop. Since hot air can absorb the moisture much better than cold air, a further substantial improvement of efficiency of regeneration of the dryer granules can be achieved by this configuration of the invention. [0049] FIG. 3 shows air-discharge/dryer device ( 2 ) as described hereinabove, with an advantageously designed version of 4/3-way valve ( 20 ) in its first valve position. Valve ( 20 ) has a housing ( 200 ), which in its portion illustrated in the lower region of FIG. 3 is provided with a larger cross section than its other portions. As an example, housing ( 200 ) can be of rotationally symmetric construction. Inside housing ( 200 ) there is disposed a valve member ( 209 ) which is rigidly joined to a piston ( 205 ) provided for actuation of valve member ( 209 ). Piston ( 205 ) is guided in housing portion ( 207 ) and sealed in housing portion ( 207 ) via a circumferential seal ( 206 ). In the depressurized or almost depressurized condition of valve ( 20 ) illustrated in FIG. 3 , piston ( 205 ) is pressed against bottom ( 222 ) of housing ( 200 ) by a spring ( 208 ), which is braced against a pedestal-shaped region ( 221 ) of housing ( 200 ). [0050] Annular seals ( 201 , 202 , 204 ), which are held in position by grooves disposed in housing ( 200 ), are disposed at certain spacings in housing ( 200 ). Valve member ( 209 ) is provided with a wall ( 210 ), which is guided inside seals ( 201 , 202 , 204 ) and can be displaced relative to seals ( 201 , 202 , 204 ) in response to a movement of piston ( 205 ). Housing ( 200 ) is provided with openings ( 223 , 224 , 225 ) to which the pressure lines ( 22 , 24 , 25 ) mentioned hereinabove are connected. Furthermore, an opening for vent port ( 215 ) is provided in the lower region of housing ( 200 ). [0051] Wall ( 210 ) of valve member ( 209 ) is provided on the side facing opening ( 224 ) with an opening ( 212 ). This opening ( 212 ) has relatively small cross section compared with the other flow cross sections of valve ( 20 ). As a result, a throttling effect, which is active in the second and third valve position of valve ( 20 ), can be achieved during flow of compressed air through opening ( 212 ). [0052] In the valve position of valve ( 20 ) illustrated in FIG. 3 , a compressed-air flow injected via compressed-air line ( 22 ) can pass through duct ( 213 ) into compressed-air line ( 24 ) and from there through air dryer ( 21 ) to check valve ( 50 ). Flow of compressed air through compressed-air line ( 25 ) is prevented by seals ( 202 , 204 ), or in other words compressed-air line ( 25 ) is shut off. According to the flow direction indicated by arrow ( 23 ), the compressed air can also propagate through an opening ( 214 ) passing through piston ( 205 ) into the space bounded by piston ( 205 ), housing underside ( 222 ) and seal ( 206 ). [0053] When the pressure injected via compressed-air line ( 22 ) into valve ( 20 ) exceeds a certain minimum value, which also depends on the friction between valve member ( 209 ) and seals ( 201 , 202 , 204 ) among other factors, piston ( 205 ) begins to move away from housing bottom ( 222 ) against the force of spring ( 208 ). Such a condition is illustrated in FIG. 4 , where the pressure present in valve ( 20 ) has already reached a magnitude at which piston ( 205 ) has executed such a substantial movement against the force of spring ( 208 ) that valve ( 20 ) has occupied its second valve position. [0054] In this second valve position, valve member ( 209 ) has reached seal ( 201 ), whereby duct ( 213 ) illustrated in FIG. 3 is shut off. As indicated by arrow ( 216 ), a flow of compressed air from compressed-air line ( 22 ) to compressed-air line ( 24 ) now takes place through opening ( 212 ), which acts as a throttling point. As illustrated by arrow ( 23 ), compressed-air propagation continues to take place through opening ( 214 ), into the space bounded by piston ( 205 ), housing bottom ( 222 ) and seal ( 206 ). Compressed-air line ( 25 ) is still shut off. [0055] As the pressure in valve ( 20 ) continues to rise, the third valve position of valve ( 20 ) is occupied, as illustrated in FIG. 5 . In this valve position, piston ( 205 ) bears against the upper side of housing region ( 207 ). A compressed-air flow from compressed-air line ( 22 ) to compressed-air line ( 24 ), as in the second valve position, continues to take place in throttled form through opening ( 212 ), as illustrated by arrow ( 216 ). The space that had previously been closed by seals ( 202 , 204 ) and that shuts off compressed-air line ( 25 ) is now opened relative to seal ( 204 ), and so compressed air can flow out of compressed-air line ( 25 ) through opening ( 215 ) into the atmosphere, as illustrated by arrow ( 217 ). [0056] An alternative embodiment of air-discharge/dryer device ( 2 ) is illustrated in FIG. 6 . Instead of the 4/3-way valve described above, a 4/2-way valve, or in other words a valve of simplified design with only two valve positions, is utilized. As a result, valve ( 20 ) can be of simpler design and can be less expensive to manufacture. [0057] In a further embodiment of the present invention, which is illustrated in FIG. 7 , air-discharge/dryer device ( 2 ) can also be equipped with an electromagnetically actuatable valve ( 20 ). Valve ( 20 ) according to FIG. 7 is provided with an electromagnet ( 27 ) as actuating element instead of with pressurized-fluid actuating means. Electromagnet ( 27 ) can be connected via an electrical line ( 26 ) to control unit ( 5 ). [0058] In a further embodiment of the present invention according to FIG. 8 , air-discharge/dryer device ( 2 ) is equipped with a pressure-controlled valve device ( 220 ), which is disposed downstream from air dryer ( 21 ). In addition, a throttle ( 28 ) is disposed upstream from air dryer ( 21 ). Valve device ( 220 ) is designed as a 3/2-way valve, which is installed in the compressed-air line connected to the pressure outlet of air dryer ( 21 ). As a result, a simple layout of the compressed-air lines on the outlet side of air dryer is achieved( 21 ). [0059] FIG. 9 illustrates a further embodiment of air-discharge/dryer device ( 2 ) that, just as depicted in FIG. 8 , provides a throttle ( 28 ) disposed upstream from air dryer ( 21 ) as well as a pressure-controlled valve device ( 29 ) disposed downstream from air dryer ( 21 ). Valve device ( 29 ) is designed as a 2/2-way valve. As a result, air-discharge/dryer device ( 2 ) can be manufactured particularly inexpensively. In an advantageous practical implementation, the additional branch point of the compressed-air lines illustrated according to FIG. 9 on the outlet side of the air dryer can be integrated directly into valve device ( 29 ), and so the routing of the compressed-air lines is not more complicated than that of the configuration according to FIG. 8 . [0060] For rapid delivery of compressed air to the air-suspension bellows or from the air-suspension bellows, throttle ( 28 ) is designed in such a way as to ensure that a compressed-air flow sufficient for the desired requirements can pass through throttle ( 28 ). On the other hand, to achieve an efficient regeneration effect for the dryer granules while valve device ( 29 ) is open, the passage cross section of valve device ( 29 , 220 ) is larger than the passage cross section of throttle ( 28 ), in the ratio, for example, of 4:1. [0061] According to FIG. 1 , there is proposed as changeover-valve device ( 3 ) an electromagnetically actuatable multiway-valve arrangement that is piloted by compressed air and comprises a pilot valve ( 31 ) and a changeover valve ( 30 ). Pilot valve ( 31 ) is designed as an electromagnetically actuated 3/2-way valve that can be actuated by control unit ( 5 ) via an electrical line. Changeover valve ( 30 ) is designed as a 4/2-way valve that can be actuated by compressed air and that is in communication via compressed-air ports ( 315 , 316 , 317 , 318 ) with the other parts of the air-suspension system. Via pilot valve ( 31 ), the compressed-air-actuatable control input of changeover valve ( 30 ) can be placed optionally in communication with the pressure discharged by compressed-air delivery device ( 1 ) via air-discharge/dryer device ( 2 ) and check valve ( 50 ), or with the atmosphere. To avoid undesirably high air consumption during actuation of changeover valve ( 30 ), the control volume of this valve is kept small. FIGS. 13 and 14 show a practical example of a changeover valve designed in this way having small control volume. Furthermore, it is advantageous to keep the changeover frequency low by suitable control algorithms in control unit ( 5 ), in order to minimize the air consumption. [0062] Compared with a 4/2-way changeover valve controlled directly by an electromagnet, valve arrangement ( 3 ) with pilot valve as illustrated in FIG. 1 has the advantage that the actuating forces that are applied by the electromagnet are smaller. As a result, the electromagnet can be of smaller and less expensive design. The fact that the pilot pressure is drawn from the compressed-air outlet branch of compressed-air delivery device ( 1 ) has the advantage that changeover-valve device ( 3 ) is functional in every operating condition of the air-suspension system. For example, it is functional even during initial startup, while compressed-air accumulator ( 9 ) is still empty. [0063] FIG. 10 illustrates an alternative construction of changeover-valve device ( 3 ) comprising a changeover valve ( 30 ) designed as a slide valve that can be actuated by an electric motor plus an electric motor ( 32 ) that can be activated by control unit ( 5 ) in order to bring about actuation. [0064] A further alternative embodiment of changeover-valve device ( 3 ) is illustrated in FIG. 11 . Instead of a single changeover valve with 4/2-way function, as explained on the basis of FIGS. 1 and 10 , a combination of two pressure-controlled 3/2-way valves ( 33 , 34 ), which can be actuated by pilot valve ( 31 ), can be utilized. As regards its compressed-air port sides ( 35 , 36 ), changeover-valve device ( 3 ) illustrated in FIG. 11 can be integrated as desired into the air-suspension system according to FIG. 1 . In other words, it is possible, for example, to place port side ( 35 ) in communication with the compressed-air delivery device and port side ( 36 ) in communication with the compressed-air accumulator or with the air-suspension bellows. Conversely, port side ( 36 ) can also be placed in communication with the compressed-air delivery device, in which case port side ( 35 ) is placed in communication with the compressed-air accumulator and the air-suspension bellows. [0065] A further embodiment of changeover-valve device ( 3 ) is indicated in FIG. 12 . Four pneumatically actuatable 2/2-way valves ( 37 , 38 , 39 , 300 ), which can be actuated by pilot valve ( 31 ), are used for changeover. As explained on the basis of FIG. 11 , the port sides ( 35 , 36 ) of changeover-valve device ( 3 ) can also be connected as desired into the air-suspension system according to FIG. 1 . [0066] An advantageously designed configuration of changeover-valve device ( 3 ) illustrated in FIG. 1 will be hereinafter described on the basis of FIGS. 13 and 14 . FIG. 13 shows changeover-valve device ( 3 ) in unactuated condition and FIG. 14 shows it in actuated condition. [0067] Changeover-valve device ( 3 ) comprises pilot valve ( 31 ) and changeover valve ( 30 ). Pilot valve ( 31 ) is provided with an electromagnet arrangement ( 301 , 302 ), which is designed as electrical coil ( 301 ) and an armature ( 302 ), which is disposed inside coil ( 301 ) and can be moved in longitudinal direction of coil ( 301 ). Armature ( 302 ) simultaneously functions as the valve-closing member. For application as the valve-closing member, the armature is equipped at one of its end faces with a seal ( 305 ) made of an elastomer and at its opposite end face with a further seal ( 306 ), also made of an elastomer. On its circumference, armature ( 302 ) is provided with grooves ( 307 , 308 ) running in longitudinal direction and functioning as air-guide ducts. Armature ( 302 ) is braced on a spring ( 304 ), which is disposed inside coil ( 301 ). Spring ( 304 ) in turn is braced on a valve closure element ( 309 ), which closes off pilot valve ( 31 ) at its upper end. Valve closure element ( 309 ) is equipped with a bore running along its longitudinal axis and functioning as pressure-outlet duct ( 303 ) for venting, to the atmosphere, the compressed air that can be injected by pilot valve ( 31 ) into changeover valve ( 30 ). [0068] Pilot valve ( 31 ) is joined to changeover valve ( 30 ) to form a rigid unit. In the unactuated condition, as illustrated in FIG. 13 , armature ( 302 ) is pressed by the force of spring ( 304 ) onto a valve seat ( 311 ) provided in changeover valve ( 30 ). In the process, seal ( 306 ) closes off valve seat ( 311 ). In this condition, seal ( 305 ) is not in contact with valve closure element ( 309 ), and so pressure outlet duct ( 303 ) is open. [0069] Changeover valve ( 30 ) comprises a valve housing ( 319 ), which is provided with various compressed-air ports ( 315 , 316 , 317 , 318 ) as well as air-guide ducts ( 314 , 312 ). Compressed-air port ( 315 ) functions as the port to the outlet side of compressed-air delivery device ( 1 ). In other words, on the basis of the diagram of FIG. 1 , it functions as the port to the outlet sides of check valves ( 50 , 52 ). Compressed-air port ( 317 ) functions as the port to the intake side of compressed-air delivery device ( 1 ). That is, according to FIG. 1 , it functions as the port to the inlet sides of check valves ( 51 , 52 ). Compressed-air port ( 318 ) functions as the port of compressed-air accumulator ( 9 ) via accumulator valve ( 8 ). Compressed-air port ( 316 ) functions as the port of air-suspension bellows ( 64 , 65 , 66 , 67 ) via bellows valves ( 60 , 61 , 62 , 63 ). [0070] Compressed air to be used for pilot action can flow via compressed-air duct ( 314 ) to pilot valve ( 31 ) or to armature ( 302 ). During actuation of pilot valve ( 31 ), electric current is applied to move armature ( 302 ) against the force of spring ( 304 ) into the position illustrated in FIG. 14 . Thereupon, valve seat ( 311 ) is released, allowing compressed air to flow via chamber ( 310 ) and via compressed-air duct ( 312 ) into a pilot chamber ( 313 ). Pilot chamber ( 313 ) is bounded by a longitudinally movable piston ( 320 ), which is urged by compressed air present in pilot chamber ( 313 ). Piston ( 320 ) is braced via a spring ( 321 ) against an opposing stop in valve housing ( 319 ). When appropriate compressed air is admitted into chamber ( 313 ), piston ( 320 ) is moved against the force of spring ( 321 ) into the position illustrated in FIG. 14 . In the process, a valve slide ( 322 ) joined rigidly to piston ( 320 ) is moved therewith into the position illustrated in FIG. 14 . [0071] Via valve slide ( 322 ), compressed-air ports ( 315 , 316 , 317 , 318 ) are placed in communication with one another in the way already explained on the basis of FIG. 1 . Thus, in the unactuated position of changeover-valve device ( 3 ) illustrated in FIG. 13 , compressed-air port ( 315 ) is in communication with compressed-air port ( 318 ), and compressed-air port ( 316 ) is in communication with compressed-air port ( 317 ). In the actuated case according to FIG. 14 , compressed-air port ( 315 ) is in communication with compressed-air port ( 316 ), and compressed-air port ( 317 ) is in communication with compressed-air port ( 318 ). [0072] Air-intake device ( 4 ) is provided as a further functional unit in FIG. 1 . It is provided with an air-intake port ( 42 ) in communication with the atmosphere, with a filter ( 41 ) for filtering out impurities of the ambient air and with a check valve ( 40 ). This type of embodiment of air-intake device ( 4 ) has the advantage that, in the event of a corresponding air demand on the intake side of compressed-air delivery device ( 1 ), for example in the event that the pressure in compressed-air accumulator ( 9 ) is too low or that valves ( 8 , 60 , 61 , 62 , 63 ) are shut off during regeneration of the dryer granules, air is automatically and adequately sucked in from the atmosphere, since check valve ( 40 ) does not need any special control. [0073] The air-suspension system described hereinabove can be operated in a number of modes of operation, which will be described in greater detail hereinafter. In the process, a number of synergy effects, by which the air-suspension system can be used particularly efficiently, are obtained in the air-suspension system illustrated in FIG. 1 as well as in the configurations according to FIGS. 2 to 14 described hereinabove. [0074] The following modes of operation of the air-suspension system will be described hereinafter: [0075] 1. “Neutral condition”: Referring to a basic condition of the air-suspension system, in which no compressed-air delivery or compressed-air movement takes place between the individual components of the air-suspension system; this condition is active in particular in the valve positions of the valves illustrated in FIG. 1 as well as when electric motor ( 6 ) is turned off. [0076] 2. “Increase”: Referring to an increase of the compressed-air quantity in one or more air-suspension bellows ( 64 , 65 , 66 , 67 ). [0077] 3. “Decrease”: Referring to a decrease of the compressed-air quantity in one or more air-suspension bellows ( 64 , 65 , 66 , 67 ). [0078] 4. “Low-pressure compensation”: Referring to compensation, by intake of air from the atmosphere, for too-low air pressure or too-small compressed-air quantity, for example in compressed-air accumulator ( 9 ). [0079] 5. “Overpressure compensation”: Referring to compensation, by venting to the atmosphere, for too-high air pressure or too-large compressed-air quantity in the air-suspension system, for example in compressed-air accumulator ( 9 ). [0080] 6. “Regeneration”: Referring to regeneration of air dryer ( 21 ), or in other words removal of moisture stored in the dryer granules of air dryer ( 21 ), for which purpose air stored in the air-suspension system or sucked in from the atmosphere is vented through air dryer ( 21 ) to the atmosphere. [0081] 7. “Starting help”: Referring to assistance, by boosting with compressed air, for startup of compressed-air delivery device ( 1 ) or its electric motor ( 6 ) used as the drive. [0082] During the first startup of the air-suspension system according to FIG. 1 , and starting from the neutral condition, compressed-air accumulator ( 9 ) as well as air-suspension bellows ( 64 , 65 , 66 , 67 ) are for the time being at a pressure level that corresponds to atmospheric pressure. A compressed-air quantity adequate for the air-suspension system to function as designed is therefore not yet present in this condition. Control unit ( 5 ) recognizes this by evaluating the displacement information supplied by displacement sensors ( 68 , 69 , 70 , 71 ). If pressure sensor ( 7 ) is also provided, control unit ( 5 ) additionally refers to the pressure information supplied by pressure sensor ( 7 ) to recognize the inadequate air quantity. In this condition, control unit ( 5 ) first activates the “Low-pressure compensation” mode of operation of the air-suspension system. [0083] For this purpose, changeover-valve device ( 3 ) is used to establish communication between outlet port ( 106 ) of compressed-air delivery device ( 1 ) and air-suspension bellows ( 64 , 65 , 66 , 67 ). As a result, compressed-air accumulator ( 9 ) is simultaneously placed in communication with the intake side of compressed-air delivery device ( 1 ). In addition, accumulator valve ( 8 ) and bellows valves ( 60 , 61 , 62 , 63 ) are switched to open position. Electric motor ( 6 ) is then turned on, whereupon compressed-air delivery device ( 1 ) begins to deliver compressed air. Since no notable air quantity can be sucked in from the branch—in communication with compressed-air accumulator ( 9 )—of the compressed-air line on the intake side of compressed-air delivery device ( 1 ), a reduced pressure relative to atmospheric pressure then develops on the intake side, causing check valve ( 40 ) to open. As a result, compressed-air delivery device ( 1 ) is able to suck in air from the atmosphere via air intake device ( 4 ). The sucked-in air is discharged on the outlet side of compressed-air delivery device ( 1 ), where it flows via air-discharge/dryer device ( 2 ), check valve ( 50 ), changeover-valve device ( 3 ) and bellows valves ( 60 , 61 , 62 , 63 ) into air-suspension bellows ( 64 , 65 , 66 , 67 ). [0084] In the process, the resulting level height is monitored via displacement sensors ( 68 , 69 , 70 , 71 ) by control unit ( 5 ). When a desired level height is reached at one of air-suspension bellows ( 64 , 65 , 66 , 67 ), control unit ( 5 ) switches the bellows valve ( 60 , 61 , 62 , 63 ) upstream from that air-suspension bellows into shut-off position. When all bellows valves ( 60 , 61 , 62 , 63 ) have been switched to shut-off position in this way, control unit ( 5 ) turns electric motor ( 6 ) off and switches accumulator valve ( 8 ) into shut-off position; and the process of filling of air-suspension bellows ( 64 , 65 , 66 , 67 ) is complete. [0085] Besides filling of air-suspension bellows ( 64 , 65 , 66 , 67 ), it may be appropriate, during startup of the air-suspension system, also to fill compressed-air accumulator ( 9 ), which initially is at atmospheric pressure. For this purpose, communication between outlet port ( 106 ) of compressed-air delivery device ( 1 ) and compressed-air accumulator ( 9 ) is established by means of changeover-valve device ( 3 ). Accumulator valve ( 8 ) is switched into open position while bellows valves ( 60 , 61 , 62 , 63 ) are left in shut-off position. Electric motor ( 6 ) is then turned on, whereupon compressed-air delivery device ( 1 ) begins to deliver compressed air. Compressed-air delivery device ( 1 ) then sucks in air from the atmosphere through air-intake device ( 4 ). The sucked-in air is discharged on the outlet side of compressed-air delivery device ( 1 ), where it flows via air-discharge/dryer device ( 2 ), check valve ( 50 ), changeover-valve device ( 3 ) and accumulator valve ( 8 ) into compressed-air accumulator ( 9 ). [0086] This process of filling compressed-air accumulator ( 9 ) can take place under time control, for example. That is, electric motor ( 6 ) is turned on for a predetermined filling-time interval. If pressure sensor ( 7 ) is provided, the resulting pressure level is monitored via pressure sensor ( 7 ) by control unit ( 5 ). After the predetermined filling-time interval has elapsed, or when a desired pressure value has been reached, control unit ( 5 ) turns electric motor ( 6 ) off once again and also switches accumulator valve ( 8 ) to shut-off position; and the process of filling compressed-air accumulator ( 9 ) is complete. [0087] The process of filling explained above, that is, the “Low-pressure compensation” mode of operation, is also activated automatically by control unit ( 5 ) in subsequent operation of the air-suspension system if an insufficient air quantity in the air-suspension system is suspected on the basis of the signals of sensors ( 7 , 68 , 69 , 70 , 71 ). [0088] In subsequent operation, that is, after compressed-air accumulator ( 9 ) and air-suspension bellows ( 64 , 65 , 66 , 67 ) have been filled for the first time, the low-pressure condition described above may develop, for example due to leaks in parts of the air-suspension system or even due to operation of the air-suspension system under altered climatic conditions, such as lower ambient temperatures. Thus, it is necessary, for example, to refill compressed air into a compressed-air accumulator ( 9 ) that had been filled to a desired nominal pressure at high ambient temperature if the vehicle equipped with the air-suspension system is being operated in a region with cooler ambient temperatures. Control unit ( 5 ) automatically recognizes such a low-pressure condition by regular evaluation of the signals of sensors ( 7 , 68 , 69 , 70 , 71 ), and in such a case automatically activates the “Low-pressure compensation” mode of operation. [0089] In the case of a vehicle that was originally operated in a cooler climatic region, it may be that the air quantity in the air-suspension system is too large for operation in a hotter climatic region. As a result, the pressure in compressed-air accumulator ( 9 ) will be above a desired or permissible limit value. In such a case, the “Overpressure compensation” mode of operation is activated. [0090] For this purpose, control unit ( 5 ), by means of changeover-valve device ( 3 ), places compressed-air accumulator ( 9 ) in communication with the intake side of compressed-air delivery device ( 1 ). To dissipate the overpressure, accumulator valve ( 8 ) can now be opened to pass compressed air from compressed-air accumulator ( 9 ) via accumulator valve ( 8 ), changeover-valve device ( 3 ), check valve ( 51 ) and compressed-air delivery device ( 1 ) to air-discharge/dryer device ( 2 ). By virtue of check valve ( 40 ), the compressed air cannot escape via air-intake device ( 4 ) under these conditions, but instead it flows through check valves ( 11 , 13 ), which open automatically in flow direction, and through compressed-air delivery device ( 1 ) without the need for electric motor ( 6 ) to be turned on. In air-discharge/dryer device ( 2 ), the arriving overpressure causes valve ( 20 ) to change over to its third valve position, thus allowing the compressed air to flow further through valve ( 20 ), compressed-air line ( 24 ), air dryer ( 21 ), compressed-air line ( 25 ) and again through valve ( 20 ) and vent port ( 215 ) into the atmosphere. In this condition, no air flows via check valve ( 50 ), since bellows valves ( 60 , 61 , 62 , 63 ), which in this operating condition are in communication with check valve ( 50 ) via changeover-valve device ( 3 ), are all in shut-off position. [0091] The “Overpressure compensation” condition can be maintained, for example, until the overpressure has been sufficiently dissipated that valve ( 20 ) automatically returns to its second valve position. In this case the overpressure is controlled and limited by suitable coordination of the compressed-air actuation of valve ( 20 ) and restoring spring ( 208 ), or in other words by appropriate choice of the active area of piston ( 205 ) and of the force of spring ( 208 ). [0092] As is evident from the foregoing, a suitable pressure range can be adjusted and maintained in the air-suspension system quasi-automatically even without use of pressure sensor ( 7 ), since on the one hand check valve ( 40 ) automatically opens at corresponding low pressure and thus enables intake of air from the atmosphere, and on the other hand valve ( 20 ) automatically opens at corresponding overpressure and permits the excess air to flow out into the atmosphere. [0093] The air-suspension system is therefore functional even without pressure sensor ( 7 ). Thus, for cost reasons, for example, it is possible to manage without this pressure sensor. Nevertheless, if a pressure sensor ( 7 ) is provided, a further advantage is achieved in that the air-suspension system is able to continue operating safely even in the event of a defect or failure of pressure sensor ( 7 ). [0094] In an air-suspension system without pressure sensor ( 7 ), for example, inadmissible overpressure in compressed-air accumulator ( 9 ) can be reliably prevented by placing compressed-air accumulator ( 9 ) in communication with valve ( 20 ), which functions as the overpressure safeguard, at regular time intervals, such as every 30 minutes. [0095] If pressure sensor ( 7 ) is used, it is possible to implement further control algorithms, which can be provided as the control program in control unit ( 5 ) and by which further advantages can be achieved in control of the air-suspension system. [0096] When pressure sensor ( 7 ) is present, control unit ( 5 ), in an advantageous configuration of the invention, performs regular monitoring of the pressure in compressed-air accumulator ( 9 ). For this purpose, control unit ( 5 ) places compressed-air accumulator ( 9 ) in communication with pressure sensor ( 7 ) by actuating accumulator valve ( 8 ) and changeover-valve device ( 3 ). In the process, compressed air is prevented by check valves ( 50 , 52 ) from propagating undesirably from compressed-air accumulator ( 9 ) into other branches of the air-suspension system. If control unit ( 5 ) detects, during such a regular check, that the pressure in compressed-air accumulator ( 9 ) has exceeded a desired limit value, control unit ( 5 ) activates the “Overpressure compensation” mode of operation. [0097] In addition, it is advantageous to provide control unit ( 5 ) with the ability to check and set the air pressure to be limited. For this purpose, control unit ( 5 ) interrupts the previously described overpressure venting via valve ( 20 ) at predetermined time intervals by toggling changeover-valve device ( 3 ) in such a way that communication is again established between pressure sensor ( 7 ) and compressed-air accumulator ( 9 ), so that the residual air pressure in the compressed-air accumulator can be measured. If a limit value stored in control unit ( 5 ) is exceeded by the measured pressure value, control unit ( 5 ) then toggles changeover-valve device ( 3 ) once again, so that further overpressure dissipation can take place via valve ( 20 ). Otherwise control unit ( 5 ) deactivates the “Overpressure compensation” mode of operation and reactivates the “Neutral condition” mode of operation. [0098] In another advantageous embodiment of the present invention, control unit ( 5 ) additionally tests the pressure values present in air-suspension bellows ( 64 , 65 , 66 , 67 ) at certain time intervals by placing one of the air-suspension bellows ( 64 , 65 , 66 , 67 ) in communication with pressure sensor ( 7 ) by appropriate control of changeover-valve device ( 3 ) and of shutoff valves ( 8 , 60 , 61 , 62 , 63 ). The measured pressure values of air-suspension bellows ( 64 , 65 , 66 , 67 ) and of compressed-air accumulator ( 9 ) are stored in control unit ( 5 ). [0099] If considerable differences develop between the pressure level in compressed-air accumulator ( 9 ) on the one hand and the pressure levels in air-suspension bellows ( 64 , 65 , 66 , 67 ) on the other hand, they can be detected by control unit ( 5 ) on the basis of the stored pressure values, and so suitable corrective actions can be initiated. For example, a large pressure difference between compressed-air accumulator ( 9 ) and air-suspension bellows ( 64 , 65 , 66 , 67 ) during delivery from the low to the high pressure level would lead to a relatively long On time of compressed-air delivery device ( 1 ). In an advantageous configuration, the On time can be shortened by programming control unit ( 5 ) in such a way that the pressure difference is limited to a predetermined value. [0100] If the pressure level of compressed-air accumulator ( 9 ) were to exceed that of air-suspension bellows ( 64 , 65 , 66 , 67 ) by more than the predetermined value, control unit ( 5 ) switches the air-suspension system into the “Overpressure compensation” mode of operation. At the same time, control unit ( 5 ) additionally turns on electric motor ( 6 ) in order to operate compressed-air delivery device ( 1 ) for a predetermined time. As a result, a specified quantity of air is pumped via valve ( 20 ) into the atmosphere. After the predetermined time has elapsed, control unit ( 5 ) turns compressed-air delivery device ( 1 ) off once again and then rechecks the pressure present in compressed-air accumulator ( 9 ). [0101] Conversely, if the pressure level of compressed-air accumulator ( 9 ) is below that of air-suspension bellows ( 64 , 65 , 66 , 67 ) by more than the predetermined value, control unit ( 5 ) switches the air-suspension system into the “Low-pressure compensation” mode of operation. As a result, air is sucked in from the atmosphere via air-intake device ( 4 ) and pumped into compressed-air accumulator ( 9 ). When a desired pressure value has been reached, control unit ( 5 ) switches the air-suspension system back to the “Neutral condition” mode of operation. [0102] During the further operation of the air-suspension system, control unit ( 5 ) checks, on the basis of the signals of displacement sensors ( 68 , 69 , 70 , 71 ), whether the level height of the vehicle body relative to the vehicle wheels or roadway corresponds to a desired index value. This index value can be selected automatically by control unit ( 5 ) from a plurality of predetermined index values or index-value functions, for example as a function of the driving situation. A predetermined index value can also be provided by manual intervention, for example by the driver. If a value below the respective index value is determined for one or more of the signals of displacement sensors ( 68 , 69 , 70 , 71 ), it indicates a need for the vehicle body to be raised at the corresponding air-suspension bellows. Thus, the corresponding air-suspension bellows are filled with additional compressed air. Hereinafter it will be assumed that this is necessary for air-suspension bellows ( 64 ). [0103] Control unit ( 5 ) then activates the “Increase” mode of operation of the air-suspension system. In the process, compressed-air accumulator ( 9 ) is placed in communication with changeover-valve device ( 3 ) by switching accumulator valve ( 8 ) to open position. Changeover-valve device ( 3 ) is switched in such a way that compressed-air accumulator ( 9 ) is placed in communication with the intake side of compressed-air delivery device ( 1 ). As a result, the outlet side of compressed-air delivery device ( 1 ) is simultaneously placed in communication with bellows valves ( 60 , 61 , 62 , 63 ). Furthermore, control unit ( 5 ) switches bellows valve ( 60 ) to open position. If the pressure level in compressed-air accumulator ( 9 ) is higher than in air-suspension bellows ( 64 ), the compressed air already flows directly via check valve ( 52 ) and additionally through compressed-air delivery device ( 1 ) into air-suspension bellows ( 64 ) even if compressed-air delivery device ( 1 ) is stationary. In other words, by means of check valve ( 52 ), compressed-air delivery device ( 1 ) can be circumvented in the manner of a bypass. By virtue of the direct communication via check valve ( 52 ), the flow resistance achieved is smaller and thus more favorable. In the process, control unit ( 5 ) monitors the filling of air-suspension bellows ( 64 ) on the basis of the pressure signal transmitted by pressure sensor ( 7 ), if it is present, and of the displacement signal transmitted by displacement sensor ( 68 ). As soon as the desired index value of level height has been reached at air-suspension bellows ( 64 ), control unit ( 5 ) switches accumulator valve ( 8 ) and bellows valve ( 60 ) to shut-off position. [0104] To accelerate the flow process, or if control unit ( 5 ) does not detect any change in the value measured by displacement sensor ( 68 ), control unit ( 5 ) turns on electric motor ( 6 ) to boost the delivery of air, whereby compressed-air delivery device ( 1 ) begins to operate. This is necessary in particular if the pressure in compressed-air accumulator ( 9 ) is lower than or at best equal to the pressure in air-suspension bellows ( 64 ) to be filled, or if filling of the air-suspension bellows is to be accelerated. When compressed-air delivery device ( 1 ) begins to operate, the delivered air flows via check valve ( 51 ), compressed-air delivery device ( 1 ), air-discharge/dryer device ( 2 ) and check valve ( 50 ) into air-suspension bellows ( 64 ). [0105] If the pressure on the outlet side of compressed-air delivery device ( 1 ), especially in volume ( 15 ), were to be lower than in air-suspension bellows ( 64 ) to be filled, for example at the beginning of the “Increase” mode of operation, undesired lowering of the level height at this air-suspension bellows ( 64 ) due to pressure equalization between air-suspension bellows ( 64 ) and volume ( 15 ) is prevented by check valve ( 50 ). For this purpose, check valve ( 50 ) is advantageously disposed as closely as possible to changeover-valve device ( 3 ), in order to minimize equalization processes via the compressed-air lines. [0106] If, during delivery of air from compressed-air accumulator ( 9 ) by compressed-air delivery device ( 1 ), it were to occur that the compressed-air quantity present in compressed-air accumulator ( 9 ) is not adequate for filling air-suspension bellows ( 64 ), which is being treated as the example, the air pressure on the intake side of compressed-air delivery device ( 1 ) would drop below atmospheric pressure, whereby check valve ( 40 ) of air intake device ( 4 ) would automatically open. As a result, compressed-air delivery device ( 1 ) can suck in the necessary air from the atmosphere automatically and without further actions by control unit ( 5 ), and thus supply the necessary air quantity in air-suspension bellows ( 64 ). [0107] Conversely, if displacement sensor ( 68 ) indicates that the level height is above the index value, air-suspension bellows ( 64 ) is vented. Control unit ( 5 ) then activates the “Decrease” mode of operation of the air-suspension system. In the process, accumulator valve ( 8 ) and bellows valve ( 60 ) are switched to open position. Moreover, changeover-valve device ( 3 ) is switched in such a way that air-suspension bellows ( 64 ) is placed in communication with the intake side of compressed-air delivery device ( 1 ) and compressed-air accumulator ( 9 ) is placed in communication with the outlet side of compressed-air delivery device ( 1 ). If the air pressure in air-suspension bellows ( 64 ) is higher than the air pressure in compressed-air accumulator ( 9 ), compressed air flows directly via check valve ( 52 ) and additionally via compressed-air delivery device ( 1 ) from air-suspension bellows ( 64 ) into compressed-air accumulator ( 9 ). Compressed-air delivery device ( 1 ) does not have to be actuated during that process. By analogy with the “Increase” mode of operation, control unit ( 5 ) monitors the venting of air-suspension bellows ( 64 ) via sensors ( 7 , 68 ). When the desired level height according to the index value has been reached in air-suspension bellows ( 64 ), control unit ( 5 ) ends the “Decrease” mode of operation by switching accumulator valve ( 8 ) and bellows valve ( 60 ) to shut-off position. [0108] To accelerate the flow process, or if control unit ( 5 ) does not detect any change in the value measured by displacement sensor ( 68 ), control unit ( 5 ) turns on electric motor ( 6 ) to boost the delivery of air, whereby compressed-air delivery device ( 1 ) begins to operate. This is necessary in particular if the pressure in air-suspension bellows ( 64 ) to be emptied is lower than or at best equal to the pressure in compressed-air accumulator ( 9 ), or if emptying of the air-suspension bellows is to be accelerated. In this mode of operation, intake of air from the atmosphere via air-intake device ( 4 ) is not an option. Compressed-air delivery device ( 1 ) therefore sucks in air from air-suspension bellows ( 64 ) via bellows valve ( 60 ), changeover-valve device ( 3 ) and check valve ( 51 ), and delivers it via air-discharge/dryer device ( 2 ), check valve ( 50 ), changeover-valve device ( 3 ) and accumulator valve ( 8 ) into compressed-air accumulator ( 9 ). [0109] If the pressure value present in compressed-air accumulator ( 9 ) is already adequate or even above a desired limit value, valve ( 20 ), which functions as the overpressure safeguard, automatically responds and switches to its third valve position, so that the compressed air delivered by compressed-air delivery device ( 1 ) is vented to the atmosphere. Independently of this automatic overpressure safeguard via valve ( 20 ), control unit ( 5 ) can also prevent further delivery of compressed air into compressed-air accumulator ( 9 ) if a predetermined pressure value—checked on the basis of the signal of pressure sensor ( 7 )—stored in control unit ( 5 ) is reached in compressed-air accumulator ( 9 ). For this purpose, control unit ( 5 ) switches accumulator valve ( 8 ) to shut-off position. The compressed air subsequently delivered by compressed-air delivery device ( 1 ) is then vented to the atmosphere via valve ( 20 ) in response to a rapidly rising pressure at the outlet side—which is shut off from compressed-air accumulator ( 9 )—of compressed-air delivery device ( 1 ). [0110] If the pressure on the intake side of compressed-air delivery device ( 1 ), especially in volume ( 10 ), is higher than in air-suspension bellows ( 64 ) to be vented, for example at the beginning of the “Decrease” mode of operation, undesired raising of the level height at this air-suspension bellows ( 64 ) due to pressure equalization between air-suspension bellows ( 64 ) and volume ( 10 ) is prevented by check valve ( 51 ). For this purpose, check valve ( 51 ) is advantageously disposed as closely as possible to changeover-valve device ( 3 ), in order to minimize equalization processes via the compressed-air lines. [0111] A typical magnitude for volume ( 10 ) in air-suspension systems for passenger cars is around 0.5 liter and for volume ( 15 ) is around 0.4 liter. By using check valves ( 50 , 51 ), it is possible to avoid a complex design for minimizing the volume in compressed-air delivery device ( 1 ), in the electric motor ( 6 ) that is frequently integrated structurally into compressed-air delivery device ( 1 ), and in air-discharge/dryer device ( 2 ). Instead, the design can be selectively optimized from the viewpoint of costs. [0112] The “Regeneration” mode of operation is used for regeneration of the dryer granules provided in air dryer ( 21 ), or in other words extraction of moisture therefrom. For this purpose, control unit ( 5 ) switches accumulator valve ( 8 ) and bellows valves ( 60 , 61 , 62 , 63 ) to shut-off position and turns on electric motor ( 6 ) to cause compressed-air delivery device ( 1 ) to begin operating. Compressed-air delivery device ( 1 ) then sucks in air from the atmosphere via air-intake device ( 4 ) and discharges this air in compressed condition on the outlet side, the compressed air being heated compared with the ambient temperature. As soon as the air pressure, which is rising on the outlet side, reaches predetermined values in this process, valve ( 20 ) switches from the first valve position, firstly to the second valve position and finally to the third valve position. In the third valve position, the compressed air flows from compressed-air line ( 22 ) into compressed-air line ( 24 ), while being throttled by valve ( 20 ). That is, the compressed air expands to a lower pressure level than the pressure level present in compressed-air line ( 22 ). Air-discharge/dryer device ( 2 ) is preferably disposed in relatively close spatial proximity to compressed-air delivery device ( 1 ), so that the heated compressed air arrives in air dryer ( 21 ) without substantial drop of temperature. The air expanded and additionally heated in this way has relatively high moisture-absorption potential, and so the compressed air flowing from air dryer ( 21 ) into compressed-air line ( 25 ) has a relatively high moisture content. This air is then vented through valve ( 20 ) into the atmosphere. As a result, there is achieved very efficient and rapid drying of the dryer granules. [0113] Otherwise, regeneration of the dryer granules is also performed whenever the already explained “Overpressure compensation” mode of operation is activated, or in other words whenever surplus compressed air stored in compressed-air accumulator ( 9 ), for example, is being dissipated via valve ( 20 ). In this case, intake of air from the atmosphere is not necessary. [0114] In a preferred configuration of the invention, which can be used in particular in an air-suspension system without pressure sensor ( 7 ), the “Regeneration” mode of operation is always activated automatically by control unit ( 5 ) subsequent to one of the other modes of operation if compressed-air delivery device ( 1 ) had been in operation at the time. In this case, control unit ( 5 ) activates the “Regeneration” mode of operation in the sense of coasting down. In other words, when a preceding mode of operation such as “Increase” is ended, accumulator valve ( 8 ) and bellows valves ( 60 , 61 , 62 , 63 ) are switched to shut-off position but electric motor ( 6 ) is not turned off immediately. Instead, it is left running for a coast-down period. As a result, compressed-air delivery device ( 1 ) continues to run and builds up an overpressure on the outlet side. The air at overpressure then escapes via valve ( 20 ) and air dryer ( 21 ), thus achieving regeneration of the dryer granules. After the predetermined coast-down period, such as, for example, 5 seconds, has elapsed, control unit ( 5 ) turns off electric motor ( 6 ), whereby the air-suspension system changes from the “Regeneration” mode of operation to the “Normal condition” mode of operation. As a result, it is ensured that the dryer granules have adequate absorption capacity for moisture at any time. [0115] As indicated above, the compressed air always flows through air dryer ( 21 ) in the same flow direction in all modes of operation of the air-suspension system. As a result, it is possible to position check valve ( 50 ) in the compressed-air line between air-discharge/dryer device ( 2 ) and changeover-valve device ( 3 ) in such a way that check valve ( 50 ) is disposed relatively closely to changeover-valve device ( 3 ), and specifically downstream from air-discharge/dryer device ( 2 ). This has the advantage that, during the “Increase” mode of operation, undesired lowering of the level height as a result of pressure equalization between volume ( 15 ) and the air-suspension bellows can be prevented particularly effectively. On the other hand, if the air-drying concept used were to be such that, during regeneration operation, compressed-air flows through air dryer ( 21 ) in the flow direction opposite to that during delivery of compressed air by compressed-air delivery device ( 1 ), as is known from DE 199 59 556 C1, check valve ( 50 ) would have to be disposed between compressed-air delivery device ( 1 ) and air-discharge/dryer device ( 2 ) in the air-suspension system according to FIG. 1 . In this case, however, check valve ( 50 ) could not prevent pressure equalization processes between the volumes present in air-discharge/dryer device ( 2 ) and the air-suspension bellows. The consequence would be that undesired lowering of the level height caused by pressure equalization can take place in the “Increase” mode of operation. [0116] From the fact that compressed air always flows in the same flow direction through air-discharge/dryer device ( 2 ) and that consequently check valve ( 50 ) is disposed in the compressed-air line between air-discharge/dryer device ( 2 ) and changeover-valve device ( 3 ), there is derived the further advantage that, during dissipation of an overpressure in the “Overpressure compensation” mode of operation, the air cannot escape into the atmosphere without flowing through air dryer ( 21 ), since check valve ( 50 ) prevents it from doing so. As a result, all compressed air vented into the atmosphere benefits regeneration of the dryer granules. [0117] In addition, control unit ( 5 ) can be provided with the capability, in the form, for example, of a subroutine of a control program executed in control unit ( 5 ), of switching the air-suspension system to “Regeneration” mode of operation if high moisture density is present in the air-suspension system. For this purpose there can be provided, for measuring the moisture content of the air in the air-suspension system, an additional moisture sensor that transmits a signal representative of the moisture content of the air to control unit ( 5 ). [0118] Finally, the air-suspension system can also be operated in the “Starting help” mode of operation. This mode of operation is needed whenever the drive power that can be applied by electric motor ( 6 ) fails to cause compressor ( 12 ) to start. This can occur, for example, in the presence of relatively high backpressure on the outlet side, or in other words in outlet space ( 150 ) of compressor ( 12 ), especially if piston ( 17 ) is located at a position approximately midway between the two dead centers. [0119] In an advantageous configuration of the present invention, which can be employed in particular for an air-suspension system without pressure sensor ( 7 ), accumulator valve ( 8 ) is first opened and changeover-valve device ( 3 ) is toggled for a brief time, or in other words is operated in each of the two valve positions. These actions take place before electric motor ( 6 ) is started. As a result, pressure equalization is established between the intake side and outlet side of compressed-air delivery device ( 1 ). Thereupon electric motor ( 6 ) is started. [0120] In a further advantageous configuration, control unit ( 5 ) recognizes a starting-help demand by periodically monitoring the pressure values measured by means of pressure sensor ( 7 ), by evaluating the stored pressure values of compressed-air accumulator ( 9 ) and of the air-suspension bellows or by monitoring the current drawn by electric motor ( 6 ). If a starting-help demand is recognized, control unit ( 5 ), by appropriate operation of changeover-valve device ( 3 ) and of shutoff valves ( 8 , 60 , 61 , 62 , 63 ), places either compressed-air accumulator ( 9 ) or an air-suspension bellows having relatively high air pressure in communication with the intake side of compressed-air delivery device ( 1 ). As a result, piston ( 17 ) of compressor ( 12 ) is urged by pressure from its underside, thus reducing the drive power that is necessary for starting compressor ( 12 ) and that is supplied by electric motor ( 6 ). When compressor ( 12 ) has started, it is possible to switch back to the desired mode of operation of the air suspension system. [0121] It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, 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. [0122] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

A pneumatic suspension system for a vehicle includes a compressed air accumulator, a compressed air transport device, at least one pneumatic bellows and an electrically controllable reversing valve used to connect the compressed air accumulator to a suction connection of the compressed air transport device, in order to increase the amount of air in the pneumatic bellows in a first switching position, and to connect an outlet connection of the compressed air transport device to the pneumatic bellows also used to connect the pneumatic bellows to the suction connection of the compressed air transport device and the outlet connection of the compressed air transport device to the pressure accumulators in a second switching position in order to reduce the amount of air in the pneumatic bellows. The reversing valve can be pre-controlled with the compressed air of the pneumatic suspension system.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is related to the following U.S. applications filed on or about the same day as the present application: Ser. No. ______, entitled “PERSONAL VAPORIZING INHALER WITH MOUTHPIECE COVER”, docket number 1222.0002; Ser. No. ______, entitled “PERSONAL VAPORIZING INHALER CARTRIDGE”, docket number 1222.0004; Ser. No. ______, entitled “ATOMIZER-VAPORIZER FOR A PERSONAL VAPORIZING INHALER”, docket number 1222.0005; Ser. No. ______, entitled “PERSONAL VAPORIZING INHALER WITH INTERNAL LIGHT SOURCE”, docket number 1222.0006; Ser. No. ______, entitled “DATA LOGGING PERSONAL VAPORIZING INHALER”, docket number 1222.0007; and, Ser. No. ______, entitled “PERSONAL VAPORIZING INHALER ACTIVE CASE”, docket number 1222.0008; whose applications are hereby incorporated herein by reference for all purposes. TECHNICAL FIELD [0002] This invention relates to personal vapor inhaling units and more particularly to an electronic flameless vapor inhaler unit that may simulate a cigarette or deliver nicotine and other medications to the oral mucosa, pharyngeal mucosa, tracheal, and pulmonary membranes. BACKGROUND [0003] An alternative to smoked tobacco products, such as cigarettes, cigars, or pipes is a personal vaporizer. Inhaled doses of heated and atomized flavor provide a physical sensation similar to smoking. However, because a personal vaporizer is typically electrically powered, no tobacco, smoke, or combustion is usually involved in its operation. For portability, and to simulate the physical characteristics of a cigarette, cigar, or pipe, a personal vaporizer may be battery powered. In addition, a personal vaporizer may be loaded with a nicotine bearing substance and/or a medication bearing substance. The personal vaporizer may provide an inhaled dose of nicotine and/or medication by way of the heated and atomized substance. Thus, personal vaporizers may also be known as electronic cigarettes, or e-cigarettes. Personal vaporizers may be used to administer flavors, medicines, drugs, or substances that are vaporized and then inhaled. BRIEF DESCRIPTION OF THE DRAWINGS [0004] FIG. 1 is a perspective view of a personal vaporizer unit. [0005] FIG. 2 is a side view of a personal vaporizer unit. [0006] FIG. 3 is an end view of the proximal end of a personal vaporizer unit. [0007] FIG. 4 is an end view of the distal end of a personal vaporizer unit. [0008] FIG. 4A is an end view of the distal end of a personal vaporizer unit having an embossed cartridge. [0009] FIG. 5 is a figure map of FIGS. 6 and 7 . [0010] FIG. 6 is a cross-section of the proximal portion of a personal vaporizer unit along the cut line shown in FIG. 2 . [0011] FIG. 7 is a cross-section of the distal portion of a personal vaporizer unit along the cut line shown in FIG. 2 . [0012] FIG. 8 is an exploded side view of components of a personal vaporizer unit. [0013] FIG. 9 is an exploded cross-section of components of a personal vaporizer unit along the cut line shown in FIG. 2 . [0014] FIG. 10 is a perspective view of a mouthpiece cover of a personal vaporizer unit. [0015] FIG. 11 is a distal end view of the mouthpiece cover of FIG. 10 . [0016] FIG. 12 is a cross-section of the mouthpiece cover along the cut line shown in FIG. 11 . [0017] FIG. 13 is a perspective view of a mouthpiece of a personal vaporizer unit. [0018] FIG. 14 is a side view of the mouthpiece of FIG. 13 . [0019] FIG. 15 is a cross-section of the mouthpiece along the cut line shown in FIG. 14 . [0020] FIG. 16 is a perspective view of a mouthpiece insulator of a personal vaporizer unit. [0021] FIG. 17 is a distal end view of the mouthpiece insulator of FIG. 16 . [0022] FIG. 18 is a side view of the mouthpiece insulator of FIG. 16 . [0023] FIG. 19 is a cross-section of the mouthpiece insulator along the cut line shown in FIG. 18 . [0024] FIG. 20 is a perspective view of a main housing of a personal vaporizer unit. [0025] FIG. 21 is a distal end view of the main housing of FIG. 20 . [0026] FIG. 22 is a proximal end view of the main housing of FIG. 20 . [0027] FIG. 23 is a side view of the main housing of FIG. 20 . [0028] FIG. 24 is a cross-section of the main housing along the cut line shown in FIG. 23 . [0029] FIG. 25 is a perspective view of a main housing of a personal vaporizer unit. [0030] FIG. 26 is a second perspective view of the main housing of FIG. 25 . [0031] FIG. 27 is a distal end view of the main housing of FIG. 25 . [0032] FIG. 28 is a proximal end view of the main housing of FIG. 25 . [0033] FIG. 29 is a side view of the main housing of FIG. 25 . [0034] FIG. 30 is a cross-section of the main housing along the cut line shown in FIG. 29 . [0035] FIG. 31 is a perspective view of a printed circuit board (PCB or PC-board) assembly of a personal vaporizer unit. [0036] FIG. 32 is a distal end view of the PCB assembly of FIG. 31 . [0037] FIG. 33 is a perspective exploded view of the PCB assembly of FIG. 31 . [0038] FIG. 34 is a side exploded view of the PCB assembly of FIG. 31 . [0039] FIG. 35 is a perspective view of a proximal wick element of a personal vaporizer unit. [0040] FIG. 35A is a perspective view of a heating element disposed through a proximal wick element of a personal vaporizer unit. [0041] FIG. 35B is a perspective view of a heating element of a personal vaporizer unit. [0042] FIG. 36 is a distal end view of the wick element of FIG. 35 . [0043] FIG. 37 is a cross-section of the wick element along the cut line shown in FIG. 35 . [0044] FIG. 38 is a perspective view of a distal wick element of a personal vaporizer unit. [0045] FIG. 39 is a distal end view of the wick element of FIG. 38 . [0046] FIG. 40 is a cross-section of the wick element along the cut line shown in FIG. 39 . [0047] FIG. 41 is a perspective view of a distal wick element of a personal vaporizer unit. [0048] FIG. 42 is a distal end view of the wick element of FIG. 41 . [0049] FIG. 43 is a cross-section of the wick element along the cut line shown in FIG. 42 . [0050] FIG. 44 is a perspective view of an atomizer housing of a personal vaporizer unit. [0051] FIG. 45 is a distal end view of the atomizer housing of FIG. 44 . [0052] FIG. 46 is a side view of the atomizer housing of FIG. 44 . [0053] FIG. 47 is a top view of the atomizer housing of FIG. 44 . [0054] FIG. 48 is a cross-section of the atomizer housing along the cut line shown in FIG. 47 . [0055] FIG. 49 is a perspective view of an atomizer housing of a personal vaporizer unit. [0056] FIG. 50 is a distal end view of the atomizer housing of FIG. 49 . [0057] FIG. 51 is a side view of the atomizer housing of FIG. 49 . [0058] FIG. 52 is a top view of the atomizer housing of FIG. 49 . [0059] FIG. 53 is a cross-section of the atomizer housing along the cut line shown in FIG. 52 . [0060] FIG. 54 is a perspective view of an atomizer housing and wicks of a personal vaporizer unit. [0061] FIG. 55 is an exploded view of the atomizer housing, wire guides, and wicks of FIG. 54 . [0062] FIG. 56 is a side view of the atomizer housing and wicks of FIG. 54 . [0063] FIG. 57 is a distal end view of the atomizer housing and wicks of FIG. 54 . [0064] FIG. 58 is a cross-section of the atomizer housing and wicks along the cut line shown in FIG. 57 . [0065] FIG. 59 is a perspective view of the proximal end wick and wire guides of FIGS. 54-58 . [0066] FIG. 59A is a perspective view showing a heating element disposed through the proximal end wick and around the wire guides of FIGS. 54-58 . [0067] FIG. 59B is a perspective view of the heating element of a personal vaporizer unit. [0068] FIG. 60 is a distal end view of the wick element of FIGS. 54-58 . [0069] FIG. 61 is a cross-section of the wick element and wire guides along the cut line shown in FIG. 60 . [0070] FIG. 62 is a perspective view of a light pipe sleeve of a personal vaporizer unit. [0071] FIG. 63 is an end view of the light pipe sleeve of FIG. 62 . [0072] FIG. 64 is a cross-section of the light pipe sleeve along the cut line shown in FIG. 63 . [0073] FIG. 65 is a perspective view of a cartridge of a personal vaporizer unit. [0074] FIG. 66 is a proximal end view of the cartridge of FIG. 65 . [0075] FIG. 67 is a side view of the cartridge of FIG. 65 . [0076] FIG. 68 is a top view of the cartridge of FIG. 65 . [0077] FIG. 69 is a cross-section of the cartridge along the cut line shown in FIG. 66 . [0078] FIG. 70 is a side view of a battery of a personal vaporizer unit. [0079] FIG. 71 is an end view of the battery of FIG. 70 . [0080] FIG. 72 is a perspective view of a battery support of a personal vaporizer unit. [0081] FIG. 73 is a perspective view of a personal vaporizer unit case. [0082] FIG. 74 is a perspective view of a personal vaporizer unit case. [0083] FIG. 75 is a block diagram of a computer system. DETAILED DESCRIPTION [0084] In an embodiment a personal vaporizer unit comprises a mouthpiece configured for contact with the mouth of a person. At least part of this mouthpiece has an antimicrobial surface. This mouthpiece may also comprise silicone rubber, thermoplastic elastomer, organosilane, silver impregnated polymer, silver impregnated thermoplastic elastomer, and/or polymer. The mouthpiece may be removed from the personal vaporizing for washing or replacement, without using a tool. The mouthpiece may be provided in different colors. Designs or other patterns may be visible on the outside of the mouthpiece. [0085] In an embodiment, a personal vaporizer unit comprises a first conductive surface configured to contact a first body part of a person holding the personal vaporizer unit, and a second conductive surface, conductively isolated from the first conductive surface, configured to contact a second body part of the person. When the personal vaporizer unit detects a change in conductivity between the first conductive surface and the second conductive surface, a vaporizer is activated to vaporize a substance so that the vapors may be inhaled by the person holding unit. The first body part and the second body part may be a lip or parts of a hand(s). The two conductive surfaces may also be used to charge a battery contained in the personal vaporizer unit. The two conductive surfaces may also form, or be part of, a connector that may be used to output data stored in a memory. [0086] In an embodiment, a personal vaporizer unit comprises a chamber configured to receive a cartridge. The cartridge may hold a substance to be vaporized. The chamber may be configured at the distal end of the personal vaporizer unit. A user may inhale the vaporized substance at the proximal end of the personal vaporizer unit. At least one space between the exterior surface of the cartridge, and an interior surface of the chamber, may define a passage for air to be drawn from outside the personal vaporizer unit, near the distal end, through the personal vaporizer unit to be inhaled by the user along with the vaporized substance. The personal vaporizer unit may also include a puncturing element that breaks a seal on the cartridge to allow a substance in the cartridge to be vaporized. An end surface of the cartridge may be translucent to diffuse light produced internally to the personal vaporizer unit. The translucent end may be etched or embossed with letters, symbols, or other indicia that are illuminated by the light produced internally to the personal vaporizer unit. [0087] In an embodiment, a personal vaporizer unit comprises a first wick element and a second wick element having a porous ceramic. The first wick element is adapted to directly contact a liquid held in a reservoir. The reservoir may be contained by a cartridge that is removable from the personal vaporizer unit. A heating element is disposed through the second wick element. An air gap is defined between the first wick element and the second wick element with the heating element exposed to the air gap. Air enters the first wick element through a hole in a housing holding the first wick element. [0088] In an embodiment, a personal vaporizer unit comprises a light source internal to an opaque cylindrical housing that approximates the appearance of a smoking article. A cylindrical light tube is disposed inside the opaque cylindrical housing to conduct light emitted by the light source to an end of the opaque cylindrical housing. This allows the light to be visible outside of the opaque cylindrical housing of the vaporizer. [0089] In an embodiment, a personal vaporizer unit comprises a microprocessor, memory, and a connector. The connector outputs data stored in the memory. The microprocessor may gather, and store in the memory, information including, but not limited to, the number of cycles the device has been triggered, the duration of the cycles, the number cartridges of fluid that are delivered. The microprocessor may also gather and store times and dates associated with the other information gathered and stored. The microprocessor may detect an empty cartridge by detecting a specific change in resistance between a wick and a housing that is equivalent to a “dry wick”, and thus signifies an empty cartridge. [0090] In an embodiment, a case comprises a cradle adapted to hold a personal vaporizer unit. The personal vaporizer unit has dimensions approximating a smoking article. The case includes a battery and at least two contacts. The two contacts may form an electrical contact with the personal vaporizer unit when the personal vaporizer unit is in the cradle. The two contacts may conduct charge from the battery to the personal vaporizer unit to charge the personal vaporizer unit. The case may also download and store data retrieved from the personnel vaporizing unit. The case may download and store this data via the at least two contacts. The case may send this data to a computer via wired or wireless links. The case may have more than one cradle and sets of contacts (e.g., two sets of two contacts in order to hold and charge two personal vaporizer units). [0091] FIG. 1 is a perspective view of a personal vaporizer unit. In FIG. 1 , personal vaporizer unit 100 comprises outer main shell 102 , mouthpiece cover 114 , mouthpiece 116 , and mouthpiece insulator 112 . The mouthpiece 116 and mouthpiece cover 114 define the proximal end of personal vaporizer unit 100 . The opposite end of personal vaporizer unit 100 will be referred to as the distal end. A cartridge 150 may be inserted into the distal end of personal vaporizer unit 100 . Cartridge 150 may hold the substance to be vaporized by personal vaporizer unit 100 . The substance after vaporizing may be inhaled by a user holding the personal vaporizer unit 100 . The substance may be in the form of a liquid or gel. [0092] FIG. 2 is a side view of a personal vaporizer unit. FIG. 2 illustrates personal vaporizer unit 100 as viewed from the side. FIG. 2 illustrates personal vaporizer unit 100 comprising outer main shell 102 , mouthpiece cover 114 , mouthpiece 116 , and mouthpiece insulator 112 . FIG. 2 also illustrates cartridge 150 inserted into the distal end of personal vaporizer unit 100 . [0093] FIG. 3 is an end view of the proximal end of a personal vaporizer unit. FIG. 3 shows the proximal end view of personal vaporizer unit 100 comprising mouthpiece cover 114 . FIG. 4 is an end view of the distal end of a personal vaporizer unit. FIG. 4 shows the distal end view personal vaporizer unit 100 comprising the visible portion of cartridge 150 . FIG. 4A is an alternative end view of personal vaporizer unit 100 comprising a visible portion of cartridge 150 that has visible logos, letters, or other symbols. These visible logos, letters, or other symbols may be illuminated or backlit by a light source internal to the personal vaporizer unit 100 . The light source may be activated intermittently under the control of a microprocessor or other electronics internal to personal vaporizer unit 100 . The light source may be activated in such a manner as to simulate the glowing ash of a cigar or cigarette. [0094] FIG. 5 is a figure map of FIGS. 6 and 7 . FIG. 6 is a cross-section of the proximal portion of a personal vaporizer unit along the cut line shown in FIG. 2 . In FIG. 6 , the proximal portion of personal vaporizer unit 100 comprises mouthpiece cover 114 , mouthpiece 116 , mouthpiece insulator 112 , outer main shell 102 , battery support 106 , and battery 104 . The mouthpiece cover 114 surrounds and is engaged with the distal end of mouthpiece 116 . Mouthpiece 116 and outer main shell 102 are preferably made of an electrically conductive material(s). Mouthpiece 116 is separated from outer main shell 102 by mouthpiece insulator 112 . Mouthpiece 116 and outer main shell 102 are thus electrically isolated from each other by mouthpiece insulator 112 . [0095] In an embodiment, personal vaporizer unit 100 is configured such that other main shell 102 comprises a first conductive surface configured to contact a first body part of a person holding personal vaporizer unit 100 . Mouthpiece 116 comprises a second conductive surface, which is conductively isolated from the first conductive surface. This second conductive surface is configured to contact a second body part of the person. When personal vaporizer unit 100 detects a change in conductivity between the first conductive surface and the second conductive surface, a vaporizer internal to personal vaporizer unit 100 is activated to vaporize a substance in cartridge 150 so that the vapors may be inhaled by the person holding personal vaporizer unit 100 . The first body part and the second body part may be a lip or parts of a hand(s). The two conductive surfaces of outer main shell 102 and mouthpiece 116 , respectively, may also be used to charge battery 104 contained in the personal vaporizer unit 100 . The two conductive surfaces of outer main shell 102 and mouthpiece 116 , respectively, may also be used to output (or input) data stored (or to be stored) in a memory (not shown). [0096] Battery support 106 functions to hold battery 104 in a position which is fixed relative to our main shell 102 . Battery support 106 is also configured to allow air and vaporized substance to pass from the distal end of personal vaporizer unit 100 past battery 104 along one or more passageways. After air and the vapors of the vaporized substance pass by battery 104 , they may pass through openings in mouthpiece 116 , mouthpiece cover 114 , and mouthpiece insulator 112 , to be inhaled by a user. [0097] FIG. 7 is a cross-section of the distal portion of a personal vaporizer unit along the cut line shown in FIG. 2 . In FIG. 7 , the distal end portion of personal vaporizer unit 100 comprises outer main shell 102 , light pipe sleeve 140 , and atomizer housing 132 , distal wick 134 , proximal wick 136 , PC board 123 , PC board 124 , spacer 128 , and main housing 160 . FIG. 7 also illustrates cartridge 150 inserted into the distal end of personal vaporizer unit 100 . As can be seen in FIG. 7 , cartridge 150 may hold a substance (e.g., a liquid or gel) in direct contact with distal wick 134 . The substance may be drawn through distal wick 134 to be vaporized inside atomizer assembly. The atomizer assembly comprises atomizer housing 132 , distal wick 134 , proximal wick 136 , and a heating element (not shown). [0098] FIG. 8 is an exploded side view of components of a personal vaporizer unit. FIG. 9 is an exploded cross-section of components of a personal vaporizer unit along the cut line shown in FIG. 2 . [0099] In FIGS. 8 and 9 , personal vaporizer unit 100 comprises (from left to right) mouthpiece cover 114 , mouthpiece 116 , mouthpiece insulator 112 , battery 104 , battery support 106 , PC board 123 , spacer 128 , PC board 124 , main housing 160 , proximal wick 136 , distal wick 134 , atomizer housing 132 , light pipe sleeve 140 , and cartridge 150 . Mouthpiece cover 114 surrounds and covers the proximal end of mouthpiece 116 . The distal end of mouthpiece 116 is inserted into mouthpiece insulator 112 . Battery 104 is held in place by battery support 106 . PC board 123 , spacer 128 and PC board 124 are disposed within main housing 160 . Proximal wick 136 and distal wick 134 are disposed within atomizer housing 132 . [0100] Atomizer housing 132 (and therefore proximal wick 136 , distal wick 134 ) are disposed inside light pipe sleeve 140 and main shell 102 . (Note: for clarity, main shell 102 is not shown in FIGS. 8 and 9 .) Light pipe sleeve 140 is disposed within main shell 102 . Light pipe sleeve 140 is positioned such that light emitted from a light source mounted on PC board 124 may be conducted via light pipe sleeve 140 to a location where it is visible on the outside of personal vaporizer unit 100 . [0101] Cartridge 150 is disposed within light pipe sleeve 140 . When assembled, a substance contained within cartridge 150 is held in direct contact with distal wick 134 . When cartridge 150 is inserted into personal vaporizer unit 100 atomizer housing 132 or distal wick 134 may puncture a seal or cap that contains the substance to be vaporized within cartridge 150 . Once punctured, the substance held within a reservoir of cartridge 150 may come in direct contact with distal wick 134 . [0102] FIG. 10 is a perspective view of a mouthpiece cover of a personal vaporizer unit. FIG. 11 is a distal end view of the mouthpiece cover of FIG. 10 . FIG. 12 is a cross-section of the mouthpiece cover along the cut line shown in FIG. 11 . As can be seen in FIGS. 10-12 , mouthpiece cover 114 has an opening 114 - 1 that allows air and the vaporized substance to be drawn through mouthpiece cover 114 . Mouthpiece cover 114 is configured for contact with the mouth of a person. In an embodiment, at least part of the mouthpiece cover has an antimicrobial surface. This antimicrobial surface of mouthpiece cover 114 may comprise, but is not limited to: silicone rubber, thermoplastic elastomer, organosilane, silver impregnated polymer, silver impregnated thermoplastic elastomer, and/or polymer. Mouthpiece cover 114 is also configured to be removable from personal vaporizer unit 100 by a user without the use of tools. This allows mouthpiece cover 114 to be replaced and/or washed. In an embodiment, mouthpiece cover 114 may be held in place on personal vaporizer unit 100 by annular ridge 114 - 2 which interfaces with a groove on mouthpiece 116 of personal vaporizer unit 100 to secure mouthpiece cover 114 in place. In another embodiment, mouthpiece cover 114 may be held in place on personal vaporizer unit 100 by a friction fit. [0103] FIG. 13 is a perspective view of a mouthpiece of a personal vaporizer unit. FIG. 14 is a side view of the mouthpiece of FIG. 13 . FIG. 15 is a cross-section of the mouthpiece along the cut line shown in FIG. 14 . As can be seen in FIGS. 13-15 , mouthpiece 116 has a passageway 116 - 1 that allows air and the vaporized substance to be drawn through mouthpiece 116 . Mouthpiece 116 may comprise a conductive surface or material configured to contact a first body part of a person holding personal vaporizer unit 100 . This first body part may be part of a hand, or at least one lip of the person holding personal vaporizer unit 100 . In an embodiment, mouthpiece 116 has an annular groove 116 - 2 around an outside surface. This groove is configured to receive annular ridge 114 - 2 . Thus, annular groove 116 - 2 helps secure mouthpiece cover 114 to personal vaporizer unit 100 . [0104] FIG. 16 is a perspective view of a mouthpiece insulator of a personal vaporizer unit. FIG. 17 is a distal end view of the mouthpiece insulator of FIG. 16 . FIG. 18 is a side view of the mouthpiece insulator of FIG. 16 . FIG. 19 is a cross-section of the mouthpiece insulator along the cut line shown in FIG. 18 . As discussed previously, mouthpiece insulator 112 is disposed between main shell 102 and mouthpiece 116 . As can be seen in FIGS. 16-18 , mouthpiece insulator 112 has a passageway 112 - 1 that allows air and the vaporized substance to be drawn through mouthpiece insulator 112 . Because mouthpiece insulator 112 is disposed between main shell 102 and mouthpiece 116 , mouthpiece insulator 112 can electrically isolate main shell 102 and mouthpiece 116 . Thus, in an embodiment, mouthpiece insulator 112 comprises, or is made of, a non-electrically conductive material. This electrical isolation between main shell 102 and mouthpiece 116 allow electrical impedance changes between main shell 102 and mouthpiece 116 to be detected. [0105] For example, a first conductive surface on mouthpiece 116 may be configured to contact a first body part of a person holding personal vaporizer unit 100 . A second conductive surface on main shell 102 (which is conductively isolated from said first conductive surface by mouthpiece insulator 112 ) may be configured to contact a second body part of the person. Personal vaporizer unit 100 may then activate in response to detecting a change in conductivity between the first conductive surface and the second conductive surface. In an embodiment, this change in conductivity may comprise a drop in impedance between the first conductive surface and the second conductive surface. In an embodiment, the change in conductivity may comprise a change in capacitance between the first conductive surface and the second conductive surface. The first body part may be a finger. The second body part may be a lip. The second body part may be a second finger. In an embodiment, the first conductive surface and the second conductive surfaces may be used to pass a charging current to battery 104 . The first and second conductive surfaces may also be used to transfer data to or from personal vaporizer unit 100 . [0106] FIG. 20 is a perspective view of a main housing of a personal vaporizer unit. FIG. 21 is a distal end view of the main housing of FIG. 20 . FIG. 22 is a proximal end view of the main housing of FIG. 20 . FIG. 23 is a side view of the main housing of FIG. 20 . FIG. 24 is a cross-section of the main housing along the cut line shown in FIG. 23 . Main housing 160 is configured to hold PC-boards 123 and 124 , and spacer 128 . Main housing 160 is configured to fit within main shell 102 via a friction fit. Main housing 160 has several holes 166 that allow light generated by a light source(s) on PC-board 124 to pass. Once this light passes through holes 166 , it may be coupled into light pipe sleeve 140 where it is conducted to a visible location on the outside of personal vaporizer unit 100 . [0107] Main housing 160 also has a hole 165 that allows an electrical conductor (not shown) to run from PC-board 123 or PC-board 124 through main housing 160 . This electrical conductor may be, or connect to, a heating element (not shown). This heating element may help vaporize the substance to be inhaled by the user of personal vaporizer unit 100 . This heating element may be controlled by circuitry on PC-board 123 or PC-board 124 . This heating element may be activated in response to a change in conductivity between the first conductive surface and the second conductive surface, described previously. [0108] The exterior of main housing 160 may also have a flat surface 164 (or other geometry) forming a galley that is configured to allow the vaporized substance and air to pass between the main housing 160 and the main shell 102 . Once the vaporized substance and air pass by main housing 160 , they may travel through passageway 112 - 1 , passageway 116 - 1 , and opening 114 - 1 to be inhaled by a user of personal vaporizer unit 100 . The exterior of main housing 160 may also have one or more standoffs 167 (or other geometries) that are configured to allow air and the vaporized substance to reach the passageway formed by flat surface 164 and main shell 102 . [0109] FIG. 25 is a perspective view of a main housing of a personal vaporizer unit. FIG. 26 is a second perspective view of the main housing of FIG. 25 . FIG. 27 is a distal end view of the main housing of FIG. 25 . FIG. 28 is a proximal end view of the main housing of FIG. 25 . FIG. 29 is a side view of the main housing of FIG. 25 . FIG. 30 is a cross-section of the main housing along the cut line shown in FIG. 29 . Main housing 260 may be used as an alternative embodiment to main housing 160 . [0110] Main housing 260 is configured to hold PC-boards 123 and 124 , and spacer 128 . Main housing 260 is configured to fit within main shell 102 via a friction fit. Main housing 260 has several holes 266 that allow light generated by a light source(s) on PC-board 124 to pass. Once this light passes through holes 266 , it may be coupled into light pipe sleeve 140 where it is conducted to a visible location on the outside of personal vaporizer unit 100 . [0111] Main housing 260 also has a hole 265 that allows an electrical conductor (not shown) to run from PC-board 123 or PC-board 124 through main housing 260 . This electrical conductor may be, or connect to, a heating element (not shown). This heating element may help vaporize the substance to be inhaled by the user of personal vaporizer unit 100 . This heating element may be controlled by circuitry on PC-board 123 or PC-board 124 . This heating element may be activated in response to a change in conductivity between the first conductive surface and the second conductive surface, described previously. [0112] The exterior of main housing 260 may also have flat surfaces 264 (or other geometry) that form a galley that is configured to allow the vaporized substance and air to pass between the main housing 260 and the main shell 102 . Once the vaporized substance and air pass by main housing 260 , they may travel through passageway 112 - 1 , passageway 116 - 1 , and opening 114 - 1 to be inhaled by a user of personal vaporizer unit 100 . The exterior of main housing 260 may also have one or more standoffs 267 (or other geometries) that are configured to allow air and the vaporized substance to reach the passageway formed by flat surfaces 264 and main shell 102 . [0113] FIG. 31 is a perspective view of a printed circuit board assembly of a personal vaporizer unit. FIG. 32 is a distal end view of the PCB assembly of FIG. 31 . FIG. 33 is a perspective exploded view of the PCB assembly of FIG. 31 . FIG. 34 is a side exploded view of the PCB assembly of FIG. 31 . As can be seen in FIGS. 31-34 , the PCB assembly is comprised of PC-board 123 and PC-board 124 separated by a spacer 128 . PC-board 124 may have mounted upon it light emitting diodes (LEDs) 125 - 127 or other light sources. LEDs 125 - 127 are configured and positioned such that when they produce light, that light passes through holes 166 or 266 in main housings 160 and 260 , respectively. This light may then be conducted by light pipe sleeve 140 to a location where it will be visible exterior to personal vaporizer unit 100 . [0114] PC-board 123 may have mounted on it a microprocessor, memory, or other circuitry (not shown) to activate or otherwise control personal vaporizer unit 100 . This microprocessor may store data about the operation of personal vaporizer unit 100 in the memory. For example, the microprocessor may determine and store the number of cycles personal vaporizer unit 100 has been triggered. The microprocessor may also store a time and/or date associated with one or more of these cycles. The microprocessor may cause this data to be output via a connector. The connector may be comprised of the first and second conductive surfaces of mouthpiece 116 and/or main shell 102 . [0115] In an embodiment, the microprocessor may determine a duration associated with various cycles where personal vaporizer unit 100 has been triggered. These durations (or a number based on these duration, such as an average) may be stored in the memory. The microprocessor may cause these numbers to be output via the connector. The microprocessor may determine an empty cartridge condition and stores a number associated with a number of times said empty cartridge condition occurs. The microprocessor, or other circuitry, may determine an empty cartridge condition determined based on a resistance between atomizer housing 132 or 232 and a wick 134 , 234 , 136 , or 236 . The microprocessor may also store a time and/or date associated with one or more of these empty cartridge conditions. The number of times an empty cartridge condition is detected, and or times and/or dates associated with these empty cartridge conditions may be output via the connector. [0116] Battery 104 , PC-board 123 , PC-board 124 , and all electronics internal to personal vaporizer unit 100 may be sealed in a plastic or plastic and epoxy compartment within the device. This compartment may include main housing 160 or 260 . All penetrations in this compartment may be sealed. Thus, only wires will protrude from the compartment. The compartment may be filled with epoxy after the assembly of battery 104 , PC-board 123 , PC-board 124 , and LEDs 125 - 127 . The compartment may be ultrasonically welded closed after assembly of battery 104 , PC-board 123 , PC-board 124 , and LEDs 125 - 127 . This sealed compartment is configured such that all vapor within personal vaporizer unit 100 does not come in contact with the electronics on PC-boards 123 or 124 . [0117] FIG. 35 is a perspective view of a proximal wick element of a personal vaporizer unit. FIG. 35A is a perspective view of a heating element disposed through a proximal wick element of a personal vaporizer unit. FIG. 35B is a perspective view of a heating element of a personal vaporizer unit. FIG. 36 is a distal end view of the wick element of FIG. 35 . FIG. 37 is a cross-section of the wick element along the cut line shown in FIG. 35 . Proximal wick 136 is configured to fit within atomizer housing 132 . As can be seen in FIGS. 35-37 , proximal wick 136 includes internal wire passageway 136 - 1 and external wire passageway 136 - 2 . These wire passageways allows a conductor or a heating element 139 to be positioned through proximal wick 136 (via internal wire passageway 136 - 1 ). This conductor or heating element 139 may also be positioned in external wire passageway 136 - 2 . Thus, as shown in FIG. 35A , a conductor or heating element 139 may be wrapped around a portion of proximal wick 136 by running the conductor or heating element 139 through internal wire passageway 136 - 1 , around the distal end of proximal wick 136 , and through external wire passageway 136 - 2 to return to approximately its point of origin. The heating element 139 may, when personal vaporizer 100 is activated, heat proximal wick 136 in order to facilitate vaporization of a substance. [0118] FIG. 38 is a perspective view of a distal wick element of a personal vaporizer unit. FIG. 39 is a distal end view of the wick element of FIG. 38 . FIG. 40 is a cross-section of the wick element along the cut line shown in FIG. 39 . Distal wick 134 is configured to fit within atomizer housing 132 . As can be seen in FIGS. 38-40 , distal wick 134 comprises two cylinders of different diameters. A chamfered surface transitions from the smaller diameter of the distal end of distal wick 134 to a larger diameter at the proximal end of distal wick 134 . The cylinder at the distal end terminates with a flat surface end 134 - 1 . This flat surface end 134 - 1 is the end of distal wick 134 is a surface that is placed in direct contact with a substance to be vaporized when cartridge 150 is inserted into the distal end of personal vaporizer 100 . The proximal end of distal wick 134 is typically in contact with proximal wick 136 . However, at least a part of proximal wick 136 and distal wick 134 are separated by an air gap. When distal wick 134 and proximal wick 136 are used together, this air gap is formed between distal wick 134 and proximal wick 136 by stand offs 136 - 3 as shown in FIG. 37 . [0119] FIG. 41 is a perspective view of a distal wick element of a personal vaporizer unit. FIG. 42 is a distal end view of the wick element of FIG. 41 . FIG. 43 is a cross-section of the wick element along the cut line shown in FIG. 42 . Proximal wick 234 may be used as an alternative embodiment to distal wick 134 . Proximal wick 234 is configured to fit within atomizer housing 232 . As can be seen in FIGS. 41-43 , proximal wick 234 comprises two cylinders of different diameters, and a cone or pointed end 234 - 1 . A chamfered surface transitions from the smaller diameter of the distal end of proximal wick 234 to a larger diameter at the proximal end of proximal wick 234 . The cylinder at the distal end terminates with a pointed end 234 - 1 . This pointed end 234 - 1 is the end of proximal wick 234 that is in direct contact with a substance to be vaporized. This pointed end 234 - 1 may also break a seal on cartridge 150 to allow the substance to be vaporized to come in direct contact with proximal wick 234 . The proximal end of proximal wick 234 is typically in contact with proximal wick 136 . However, at least a part of proximal wick 136 and proximal wick 234 are separated by an air gap. When distal wick 134 and proximal wick 236 are used together, this air gap is formed between proximal wick 234 and proximal wick 136 by stand offs 136 - 3 as shown in FIG. 37 . [0120] FIG. 44 is a perspective view of an atomizer housing of a personal vaporizer unit. FIG. 45 is a distal end view of the atomizer housing of FIG. 44 . FIG. 46 is a side view of the atomizer housing of FIG. 44 . FIG. 47 is a top view of the atomizer housing of FIG. 44 . FIG. 48 is a cross-section of the atomizer housing along the cut line shown in FIG. 47 . Atomizer housing 132 is configured to fit within main shell 102 . As can be seen in FIGS. 44-48 , atomizer housing 132 comprises roughly two cylinders of different diameters. A chamfered surface 132 - 3 transitions from the smaller diameter of the distal end of atomizer housing 132 to a larger diameter at the proximal end of atomizer housing 132 . The larger diameter at the proximal end of atomizer housing 132 is configured to be press fit into light pipe sleeve 140 . The cylinder at the distal end terminates with a spade shaped tip 132 - 2 . This spade shaped tip 132 - 2 may break a seal on cartridge 150 to allow the substance to be vaporized to come in direct contact with distal wick 134 . Other shaped tips are possible (e.g., needle or spear shaped). [0121] Chamfered surface 132 - 3 has one or more holes 132 - 1 . These holes allow air to pass, via suction, through atomizer housing 132 into distal wick 134 . This suction may be supplied by the user of personal vaporizer 100 sucking or inhaling on mouthpiece cover 114 and/or mouthpiece 116 . The air that is sucked into distal wick 134 enters distal wick 134 on or near the chamfered surface between the two cylinders of distal wick 134 . The air that is sucked into distal wick 134 displaces some of the substance being vaporized that has been absorbed by distal wick 134 causing it to be atomized as it exits distal wick 134 into the air gap formed between distal wick 134 and proximal wick 136 . The heating element disposed around proximal wick 136 may then vaporize at least some of the atomized substance. In an embodiment, one or more holes 132 - 1 may range in diameter between 0.02 and 0.0625 inches. [0122] In an embodiment, placing holes 132 - 1 at the leading edge of the chamfered surface places a set volume of the substance to be vaporized in the path of incoming air. This incoming air has nowhere to go but through the large diameter (or “head”) end of the distal end wick 134 . When the air enters this area in distal end wick 134 it displaces the substance to be vaporized that is suspended in distal end wick 134 towards an air cavity between distal end wick 134 and proximal end wick 136 . When the displaced substance to be vaporized reaches the surface of distal end wick 134 , it is forced out of the wick by the incoming air and the negative pressure of the cavity. This produces an atomized cloud of the substance to be vaporized. In an embodiment, the diameter of the head of distal end wick 134 may be varied and be smaller than the diameter of the proximal end wick 136 . This allows for a tuned volume of air to bypass proximal end wick 136 and directly enter the cavity between distal wick 134 and distal wick 136 without first passing through distal wick 136 . [0123] FIG. 49 is a perspective view of an atomizer housing of a personal vaporizer unit. FIG. 50 is a distal end view of the atomizer housing of FIG. 49 . FIG. 51 is a side view of the atomizer housing of FIG. 49 . FIG. 52 is a top view of the atomizer housing of FIG. 49 . FIG. 53 is a cross-section of the atomizer housing along the cut line shown in FIG. 52 . Atomizer housing 232 is an alternative embodiment, for use with proximal wick 234 , to atomizer house 132 . Atomizer housing 232 is configured to fit within main shell 102 and light pipe sleeve 140 . As can be seen in FIGS. 49-53 , atomizer housing 232 comprises roughly two cylinders of different diameters. A chamfered surface 232 - 3 transitions from the smaller diameter of the distal end of atomizer housing 232 to a larger diameter at the proximal end of atomizer housing 232 . The larger diameter at the proximal end of atomizer housing 232 is configured to be press fit into light pipe sleeve 140 . The cylinder at the distal end terminates with an open cylinder tip 232 - 2 . This open cylinder tip 232 - 2 allows the pointed end 234 - 1 of proximal wick 234 to break a seal on cartridge 150 to allow the substance to be vaporized to come in direct contact with proximal wick 234 . [0124] Chamfered surface 232 - 3 has one or more holes 232 - 1 . These holes allow air to pass, via suction, through atomizer housing 232 into proximal wick 234 . The air that is sucked into proximal wick 234 enters proximal wick 234 on or near the chamfered surface between the two cylinders of proximal wick 234 . The air that is sucked into proximal wick 234 displaces some of the substance being vaporized that has been absorbed by proximal wick 234 causing it to be atomized as it exits proximal wick 234 into the air gap formed between proximal wick 234 and proximal wick 136 . The heating element disposed around proximal wick 136 may then vaporize at least some of the atomized substance being vaporized. In an embodiment, one or more holes 232 - 1 may range in diameter between 0.02 and 0.0625 inches. [0125] In an embodiment, placing holes 232 - 1 at the leading edge of the chamfered surface places a set volume of the substance to be vaporized in the path of incoming air. This incoming air has nowhere to go but through the head of the distal end wick 234 . When the air enters this area in distal end wick 234 it displaces the substance to be vaporized that is suspended in distal end wick 234 towards an air cavity between distal end wick 234 and proximal end wick 236 . When the displaced substance to be vaporized reaches the surface of distal end wick 232 , it is forced out of the wick by the incoming air and the negative pressure of the cavity. This produces an atomized cloud of the substance to be vaporized. In an embodiment, the diameter of the head of distal end wick 234 may be varied and be smaller than the diameter of the proximal end wick 236 . This allows for a tuned volume of air to bypass distal wick 236 and directly enter the cavity between proximal wick 234 and distal wick 236 without first passing through distal wick 236 . [0126] FIG. 54 is a perspective view of an atomizer housing and wicks of a personal vaporizer unit. FIG. 55 is an exploded view of the atomizer housing, wire guides, and wicks of FIG. 54 . FIG. 56 is a side view of the atomizer housing and wicks of FIG. 54 . FIG. 57 is a distal end view of the atomizer housing and wicks of FIG. 54 . FIG. 58 is a cross-section of the atomizer housing and wicks along the cut line shown in FIG. 57 . The atomizer housing and wicks shown in FIGS. 54-58 is an alternative embodiment for use with proximal wick 236 . The embodiment shown in FIGS. 54-58 use atomizer housing 232 , proximal wick 234 , proximal wick 236 , wire guide 237 , and wire guide 238 . Proximal wick 236 is configured to fit within atomizer housing 232 . As can be seen in FIGS. 54-58 , proximal wick 236 includes internal wire passageway 236 - 1 . This wire passageway 236 - 1 allows a conductor or a heating element (not shown) to be positioned through proximal wick 236 (via internal wire passageway 236 - 1 ). The conductor or heating element may be positioned around wire guide 237 and wire guide 238 . Thus, a conductor or heating element may run the through wire passageway 236 - 1 , around wire guides 237 and 238 , and then back through wire passageway 236 - 1 to return to approximately its point of origin. The heating element may, when personal vaporizer unit 100 is activated, heat proximal wick 236 in order to facilitate vaporization of a substance. [0127] FIG. 59 is a perspective view of the proximal end wick assembly of FIGS. 54-58 . FIG. 59A is a perspective view showing a heating element disposed through the proximal end wick and around the wire guides of FIGS. 54-58 . FIG. 59B is a perspective view of the heating element of a personal vaporizer unit. FIG. 60 is a distal end view of the wick element and wire guides of FIGS. 54-58 . FIG. 61 is a cross-section of the wick element and wire guides along the cut line shown in FIG. 60 . As can be seen in FIG. 59A , a conductor or heating element 239 may run through wire passageway 236 - 1 , around wire guides 237 and 238 , and then back through wire passageway 236 - 1 to return to approximately its point of origin. [0128] In an embodiment, distal wicks 134 , 234 , and proximal wicks 136 , 236 , may be made of, or comprise, for example a porous ceramic. Distal wicks 134 , 234 , and proximal wicks 136 , 236 , may be made of, or comprise aluminum oxide, silicon carbide, magnesia partial stabilized zirconia, yttria tetragonal zirconia polycrystal, porous metal (e.g., steel, aluminum, platinum, titanium, and the like), ceramic coated porous metal, woven metal, spun metal, metal wool (e.g., steel wool), porous polymer, porous coated polymer, porous silica (i.e., glass), and/or porous Pyrex. Distal wicks 134 , 234 , and proximal wicks 136 , 236 , may be made of or comprise other materials that can absorb a substance to be vaporized. [0129] The conductor or heating element that is disposed through proximal wick 136 or 236 may be made of, or comprise, for example: nickel chromium, iron chromium aluminum, stainless steel, gold, platinum, tungsten molybdenum, or a piezoelectric material. The conductor or heating element that is disposed through proximal wick 136 can be made of, or comprise, other materials that become heated when an electrical current is passed through them. [0130] FIG. 62 is a perspective view of a light pipe sleeve of a personal vaporizer unit. FIG. 63 is an end view of the light pipe sleeve of FIG. 62 . FIG. 64 is a cross-section of the light pipe sleeve along the cut line shown in FIG. 63 . Light pipe sleeve 140 is configured to be disposed within main shell 102 . Light pipe sleeve 140 is also configured to hold cartridge 150 and atomizer housing 132 or 232 . As discussed previously, light pipe sleeve 140 is configured to conduct light entering the proximal end of light pipe sleeve 140 (e.g., from LEDs 125 - 127 ) to the distal end of light pipe sleeve 140 . Typically, the light exiting the distal end of light pipe sleeve 140 will be visible from the exterior of personal vaporizer 100 . The light exiting the distal end of light pipe sleeve 140 may be diffused by cartridge 150 . The light exiting the distal end of light pipe sleeve 140 may illuminate characters and/or symbols drawn, printed, written, or embossed, etc., in an end of cartridge 150 . In an embodiment, light exiting light pipe sleeve 140 may illuminate a logo, characters and/or symbols cut through outer main shell 102 . In an embodiment, light pipe sleeve 140 is made of, or comprises, a translucent acrylic plastic. [0131] FIG. 65 is a perspective view of a cartridge of a personal vaporizer unit. FIG. 66 is a proximal end view of the cartridge of FIG. 65 . FIG. 67 is a side view of the cartridge of FIG. 65 . FIG. 68 is a top view of the cartridge of FIG. 65 . FIG. 69 is a cross-section of the cartridge along the cut line shown in FIG. 66 . As shown in FIGS. 65-69 , cartridge 150 comprises a hollow cylinder section with at least one exterior flat surface 158 . The flat surface 158 forms, when cartridge 150 is inserted into the distal end of personal vaporizer unit 100 , an open space between the exterior surface of the cartridge and an interior surface of light pipe sleeve 140 . This space defines a passage for air to be drawn from outside personal vaporizer unit 100 , through personal vaporizer unit 100 to be inhaled by the user along with the vaporized substance. This space also helps define the volume of air drawn into personal vaporizer unit 100 . By defining the volume of air typically drawn into the unit, different mixtures of vaporized substance to air may be produced. [0132] The hollow portion of cartridge 150 is configured as a reservoir to hold the substance to be vaporized by personal vaporizer unit 100 . The hollow portion of cartridge 150 holds the substance to be vaporized in direct contact with distal wick 134 or 234 . This allows distal wick 134 or 234 to become saturated with the substance to be vaporized. The area of distal wick 134 or 234 that is in direct contact with the substance to be vaporized may be varied in order to deliver different doses of the substance to be vaporized. For example, cartridges 150 with differing diameter hollow portions may be used to deliver different doses of the substance to be vaporized to the user. [0133] Cartridge 150 may be configured to confine the substance to be vaporized by a cap or seal (not shown) on the proximal end. This cap or seal may be punctured by the end of atomizer housing 132 , or the pointed end 234 - 1 of proximal wick 234 . [0134] When inserted into personal vaporizer unit 100 , cartridge standoffs 157 define an air passage between the end of light pipe sleeve 140 and main shell 102 . This air passage allows air to reach the air passage defined by flat surface 158 . [0135] The hollow portion of cartridge 150 also includes one or more channels 154 . The end of these channels are exposed to air received via the air passage(s) defined by flat surface 158 . These channels allow air to enter the hollow portion of cartridge 150 as the substance contained in cartridge 150 is drawn into a distal wick 134 or 234 . Allowing air to enter the hollow portion of cartridge 150 as the substance contained in cartridge 150 is removed prevents a vacuum from forming inside cartridge 150 . This vacuum could prevent the substance contained in cartridge 150 from being absorbed into distal wick 134 or 234 . [0136] In an embodiment, cartridge 150 may be at least partly translucent. Thus cartridge 150 may act as a light diffuser so that light emitted by one or more of LEDs 125 - 127 is visible external to personal vaporizer unit 100 . [0137] FIG. 70 is a side view of a battery of a personal vaporizer unit. FIG. 71 is an end view of the battery of FIG. 70 . FIG. 72 is a perspective view of a battery support of a personal vaporizer unit. As can be seen in FIG. 72 , battery support 106 does not form a complete cylinder that completely surrounds battery 104 . This missing portion of a cylinder forms a passageway that allows air and the vaporized substance to pass by the battery from the atomizer assembly to the mouthpiece 116 so that it may be inhaled by the user. [0138] FIG. 73 is a top perspective view of a personal vaporizer unit case. FIG. 74 is a bottom perspective view of a personal vaporizer unit case. Personal vaporizer case 500 is configured to hold one or more personal vaporizer units 100 . Personal vaporizer case 500 includes a connector 510 to interface to a computer. This connector allows case 500 to transfer data from personal vaporizer unit 100 to a computer via connector 510 . Case 500 may also transfer data from personal vaporizer unit 100 via a wireless interface. This wireless interface may comprise an infrared (IR) transmitter, a Bluetooth interface, an 802.11 specified interface, and/or communicate with a cellular telephone network. Data from a personal vaporizer unit 100 may be associated with an identification number stored by personal vaporizer unit 100 . Data from personal vaporizer unit 100 may be transmitted via the wireless interface in association with the identification number. [0139] Personal vaporizer case 500 includes a battery that may hold charge that is used to recharge a personal vaporizer unit 100 . Recharging of personal vaporizer unit 100 may be managed by a charge controller that is part of case 500 . [0140] When case 500 is holding a personal vaporizer unit 100 , at least a portion of the personal vaporizer unit 100 is visible from the outside of case 500 to allow a light emitted by personal vaporizer unit 100 to provide a visual indication of a state of personal vaporizer unit 500 . This visual indication is visible outside of case 500 . [0141] Personal vaporizer unit 100 is activated by a change in impedance between two conductive surfaces. In an embodiment, these two conductive surfaces are part of main shell 102 and mouthpiece 116 . These two conductive surfaces may also be used by case 500 to charge battery 104 . These two conductive surfaces may also be used by case 500 to read data out of personal vaporizer unit 100 . [0142] In an embodiment, when a user puts personal vaporizer unit 100 in his/her mouth and provides “suction,” air is drawn into personal vaporizer unit 100 though a gap between the end of main shell 102 and cartridge 150 . In an embodiment, this gap is established by standoffs 157 . Air travels down galley(s) formed by flat surface(s) 158 and the inner surface of light pipe sleeve 140 . The air then reaches a “ring” shaped galley between atomizer housing 132 , cartridge 150 , and light pipe sleeve 140 . Air travels to distal wick 134 via one or more holes 132 - 1 , in chamfered surface(s) 132 - 3 . Air travels to distal wick 234 via one or more holes 232 - 1 , in chamfered surface(s) 232 - 3 . Air is also allowed to enter cartridge 150 via one or more channels 154 . This air entering cartridge 150 via channels 154 “back fills” for the substance being vaporized which enters distal wick 134 . The substance being vaporized is held in direct contact with distal wick 134 or 234 by cartridge 150 . The substance being vaporized is absorbed by and may saturate distal wick 134 or 234 and proximal wick 136 or 236 . [0143] The incoming air drawn through holes 132 - 1 displaces from saturated distal wick 134 the substance being vaporized. The displaced substance being vaporized is pulled from wick elements 134 into a cavity between distal wick 134 and 136 . This cavity may also contain a heating element that has been heated to between 150-200° C. The displaced substance being vaporized is pulled from wick elements 134 in small (e.g., atomized) droplets. These atomized droplets are vaporized by the heating element. [0144] In an embodiment, when a user puts personal vaporizer unit 100 in his/her mouth and provides “suction,” air is drawn into personal vaporizer unit 100 though a gap between the end of main shell 102 and cartridge 150 . In an embodiment, this gap is established by standoffs 157 . Air travels down galley(s) formed by flat surface(s) 158 and the inner surface of light pipe sleeve 140 . The air then reaches a “ring” shaped galley between atomizer housing 232 , cartridge 150 , and light pipe sleeve 140 . Air travels to proximal wick 234 via one or more holes 232 - 1 , in chamfered surface(s) 232 - 1 . Air is also allowed to enter cartridge 150 via one or more channels 154 . This air entering cartridge 150 via channels 154 “back fills” for the substance being vaporized which enters proximal wick 234 . The substance being vaporized is held in direct contact with proximal wick 234 by cartridge 150 . The substance being vaporized is absorbed by and may saturate distal wick 243 and proximal wick 236 . [0145] The incoming air drawn through holes 232 - 1 displaces from saturated proximal wick 234 the substance being vaporized. The displaced substance being vaporized is pulled from wick elements 234 into a cavity between wick distal wick 234 and proximal wick 236 . This cavity may also contain a heating element that has been heated to between 150-200° C. The displaced substance being vaporized is pulled from distal wick 234 in small (e.g., atomized) droplets. These atomized droplets are vaporized by the heating element. [0146] In both of the previous two embodiments, the vaporized substance and air are drawn down a galley adjacent to battery 104 , through mouthpiece insulator 112 , mouthpiece 116 , and mouthpiece cover 114 . After exiting personal vaporizer unit 100 , the vapors may be inhaled by a user. [0147] The systems, controller, and functions described above may be implemented with or executed by one or more computer systems. The methods described above may be stored on a computer readable medium. Personal vaporizer unit 100 and case 500 may be, comprise, or include computers systems. FIG. 75 illustrates a block diagram of a computer system. Computer system 600 includes communication interface 620 , processing system 630 , storage system 640 , and user interface 660 . Processing system 630 is operatively coupled to storage system 640 . Storage system 640 stores software 650 and data 670 . Processing system 630 is operatively coupled to communication interface 620 and user interface 660 . Computer system 600 may comprise a programmed general-purpose computer. Computer system 600 may include a microprocessor. Computer system 600 may comprise programmable or special purpose circuitry. Computer system 600 may be distributed among multiple devices, processors, storage, and/or interfaces that together comprise elements 620 - 670 . [0148] Communication interface 620 may comprise a network interface, modem, port, bus, link, transceiver, or other communication device. Communication interface 620 may be distributed among multiple communication devices. Processing system 630 may comprise a microprocessor, microcontroller, logic circuit, or other processing device. Processing system 630 may be distributed among multiple processing devices. User interface 660 may comprise a keyboard, mouse, voice recognition interface, microphone and speakers, graphical display, touch screen, or other type of user interface device. User interface 660 may be distributed among multiple interface devices. Storage system 640 may comprise a disk, tape, integrated circuit, RAM, ROM, network storage, server, or other memory function. Storage system 640 may be a computer readable medium. Storage system 640 may be distributed among multiple memory devices. [0149] Processing system 630 retrieves and executes software 650 from storage system 640 . Processing system may retrieve and store data 670 . Processing system may also retrieve and store data via communication interface 620 . Processing system 650 may create or modify software 650 or data 670 to achieve a tangible result. Processing system may control communication interface 620 or user interface 670 to achieve a tangible result. Processing system may retrieve and execute remotely stored software via communication interface 620 . [0150] Software 650 and remotely stored software may comprise an operating system, utilities, drivers, networking software, and other software typically executed by a computer system. Software 650 may comprise an application program, applet, firmware, or other form of machine-readable processing instructions typically executed by a computer system. When executed by processing system 630 , software 650 or remotely stored software may direct computer system 600 to operate as described herein. [0151] The above description and associated figures teach the best mode of the invention. The following claims specify the scope of the invention. Note that some aspects of the best mode may not fall within the scope of the invention as specified by the claims. Those skilled in the art will appreciate that the features described above can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific embodiments described above, but only by the following claims and their equivalents.

A personal vapor inhaling unit is disclosed. An electronic flameless vapor inhaler unit that may simulate a cigarette has a cavity that receives a cartridge in the distal end of the inhaler unit. The cartridge brings a substance to be vaporized in contact with a wick. When the unit is activated, and the user provides suction, the substance to be vaporized is drawn out of the cartridge, through the wick, and is atomized by the wick into a cavity containing a heating element. The heating element vaporizes the atomized substance. The vapors then continue to be pulled by the user through a mouthpiece and mouthpiece cover where they may be inhaled.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to fabrication of rectifiers for electric current. 2. Prior Art Known rectifiers can be made of material such as galena, selenium, copper oxide and germanium. Although rectifiers containing these materials are useful for many purposes, they are not generally satisfactory in high temperature operation. For example, selenium rectifiers are not satisfactory at temperatures over 125° C., copper oxide is not satisfactory at temperatures at over 85° to 90° C. Galena is unsatisfactory at over 70° C. and germanium is unsatisfactory over 90° C. Nevertheless, there are applications where high temperature rectifiers are required. For example, in some automotive applications the temperature in and around the engine exhaust is relatively high and there is a need for rectifying electrical circuit elements. Without the ability to endure such high temperature, the rectification components impose serious constraints on the design and must typically be positioned in the passenger compartment. This, of course, undesirably adds to the cost and complexity of the system. The prior art also teaches titanium dioxide rectifiers which can perform rectification at temperatures in excess of 200° C. However, the structure and method of manufacture disclosed in U.S. Pat. Nos. 2,699,522 and 2,887,633 have an undesirable complexity. The structure taught in both patents utilizes a titanium dioxide ceramic between dissimilar electrode material thus forming an asymmetrical structure with respect to choice of electrode materials. The cause of rectification can be described in terms of Schottky boundary layers between a semiconductor ceramic and a dissimilar electrode. In U.S. Pat. No. 2,887,633 there is taught coating an inorganic artificial barrier material on a titanium dioxide semiconductor. The coating is obtained by vaporizing silicon monoxide in a vacuum and condensing the vapor on the surface of the semiconducting titanium dioxide. An alternative solution both in structure and method would be desirable for achieving a high temperature rectifier. SUMMARY OF THE INVENTION This specification discloses a method of fabricating a titanium rectifier circuit element including the steps of forming a structure with a titanium dioxide main body with a pair of spaced faces and a platinum electrode on each of the spaced faces. Additional steps include applying a dc voltage across the structure, heating the structure to a temperature of about 750°-850° C., applying an oxidizing atmosphere, applying a reducing atmosphere, and cooling the structure. Such a rectifier has a symmetrical configuration (with respect to choice of electrode materials) with platinum electrodes attached to a titanium dioxide main body. Further, in contrast to rectification caused by Schottky boundary layers, the cause of rectification is a microstructure that results from a combination of circumstances; (1) the presence of platinum, (2) the presence of an electrical ordering field, (3) the presence of a crystallographic shear phenomenon in titanium dioxide, (4) a heat treatment that causes platinum to diffuse into the rutile grains in substantial concentrations and react with titanium to produce microscopic layer defects of PtTi 3 , which may be nucleated along crystallographic shear planes, but grown with epitaxial relation to the titanium dioxide substrate in the [100] direction. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is graphical representation of current versus voltage characteristics of a rectifier in accordance with an embodiment of this invention; FIGS. 2a, 2b, 2c and 2d are schematic representations of the structure of a platinum doped titanium dioxide ceramic during growth of a PtTi 3 microstructure in accordance with an embodiment of this invention; and FIGS. 3a, 3b, 3c , and 3d are perspective representations of various stages of fabrication of a rectifier in accordance with an embodiment of this invention. DETAILED DESCRIPTION OF THE INVENTION Fabrication of a rectifier in accordance with an embodiment of this invention, includes formation of porous, fine grain, polycrystalline titanium dioxide ceramic pellets, approximately 3 mm in diameter and 1 mm thick, with two fine (200 microns) embedded leads of platinum wire. The ceramic in the pellet is titanium dioxide in the form of rutile, fabricated by a process that produced a ceramic body having a desity of approximately 60% of theoretical and a grain size in the range of 2 to 10 microns. Rutile, a high purity, stoichiometric, single crystal, is a wide band gap semiconductor with a band gap energy in the range of 3 to 4 eV. If exposed to a reducing gas (e.g. carbon monoxide or hydrogen) at high temperatures (e.g. greater than about 400° C.), the rutile material shows, when returned to room temperature, increased conductivity. Referring to the formula TiO x , values of conductivity range over many orders of magnitude as x is varied between 2.00 and 1.75. In view of this behavior, TiO x is considered to be a defect semiconductor. That is, microstructures or defects due to oxygen vacancies within the material are responsible for this behavior. The defects tend to organize into planar defect structures and, in certain temperature ranges, phases with intermediate compositions, Ti n O n-1 , may form and be stable. Furthermore, a transformation of defect structures called "crystallographic shear" is known to take place in the TiO x material. The crystallographic shear transformation converts a planar array of oxygen vacancies into a planar array of titanium interstitial ions. Quasi-ferroelectric phenomena have been observed in samples of platinum doped TiO x . These quasi-ferroelectric phenomena are indicators that, at the microscopic level, behavior similar to that observed for polar materials can occur in platinum doped TiO x . It is suggested that the polar behavior is the result of introducing PtTi 3 planar layers into the crystalline structure. That is, the interfacial layer between the TiO 2 rutile and the PtTi 3 is believed to be the seat of the polar behavior. All the titanium dioxide ceramic pellets have platinum (Pt) present in some form. The form of platinum present in the material is important because the reaction that takes place between Pt and Ti under certain conditions produces a solid, semiconductor ceramic with an asymmetrical direct current conductivity. Platinum in the starting pellet can be present only in the lead wires. Alternatively, platinum can be present at the start both in the lead wires and in the form of fine particles (about 0.1 to 0.5 micron diameter) dispersed throughout the ceramic body. The particular treatment, in accordance with an embodiment of this invention, that produces titanium dioxide ceramic with electrical rectification characteristics includes the following steps: (1) Connect the leads of the smaple to a source of 1 volt dc and leave the voltage applied during all the subsequent steps described here. (2) Heat the sample to a temperature between 750° to 850° C. (3) While the sample is above 750° begin cycling the sample between oxidizing (4% O 2 in N 2 ) and reducing (2% CO in N 2 or 2% H 2 in H 2 ) atmospheres. The total time for a complete oxidation-reduction cycle is about 4 minutes, and the number of cycles is about 100. (4) Lower the temperature, continuing to cycle the sample, until temperature of approximately 600° C. is reached. (5) Around 600° C., stop cycling and place the reducing atmosphere over the sample. Allow the smaple to cool back down to room tempertature in the presence of the reducing atmosphere. Before this treatment is begun, a pellet of titanium dioxide ceramic normally has a resistance of about 50 megohms or greater and shows no asymmetry in conductivity. After being subjected to the treatment described, the low resistance direction (forward direction) of current flow can be as low as about 5,000 ohms, with a resistance in the direction of reverse current flow up to twenty times larger than the forward direction. Thus, after the treatment just outlined, the material has a rectification characteristic and a room temperature conductivity in the forward direction that is about four orders of magnitude larger than that in the untreated material. As a result of fabrication in accordance with an embodiment of this invention, the rectifier structure has a symmetrical configuration with platinum as both electrodes. The cause of the rectification is ascribed to a defect microstructure that results form a combination of circumstances: (i) the presence of platinum, (ii) the presence of an electrical ordering field, (iii) the presence of the crystallographic shear phenomenon in titanium dioxide, (iv) a heat treatment that causes platinum to diffuse into the rutile grains in substantial concentrations and react with the Ti to produce microscopic layer defects of ptTi 3 , which may be nucleated along crystallographic shear planes, but grown with an epitaxial relation to the titanium dioxide substrate in [100] direction. The current versus voltage characteristic (I-V curve) of a rectifier structure fabricated as described above is shown in FIG. 1. The formation of the microstructural defects responsible for the asymmetrical conductivity in titanium dioxide depends upon the presence of platinum. Samples showing strong rectification characteristics have had approximately 2% platinum present in the rutile structure. The cyclic oxidation reduction process causes the platinum to react with the titanium dioxide and undergo a reduction in particle size and a dispersion (probably of platinum atoms) into the rutile crystal structure. The platinum reacts with the titanium dioxide to form an intermetallic precipitate, PtTi 3 . This precipitate is first formed as a cloud of fine point defects in the titanium dioxide matrix. With continued cycling, the PtTi 3 particles agglomerate and form planar microstructures, probably under the influence of the crystallographic shear process. The microstructures can be considered to be defects in the rutile structure. The individual PtTi 3 planar defect structures at this point are epitaxial layers, about 30 Angstroms thick and sandwiched between rutile crystal structures. Further treatment results in the formation of multiple layered planar microstructures. The sequence of microstructures or defects formed by the cyclic oxidation reduction heat treatment described in the preceding paragraph is outlined in the drawings of FIGS. 2a, 2b, 2c and 2d. FIG. 2a shows an overall view of a collection of grains indicating that, probably as a result of varying impurity concentrations, the grains are in various stages of developing the microstructural defects. FIG. 2d indicates that the expitaxial layers are on (100) faces with the normal to these planes corresponding to a [010] direction in both the TiO 2 and PtTi 3 crystal structures. The defect structures that are most responsible for the rectification effect are probably those in FIG. 2c. These single layered structures will have the greatest surface area to volume ratio. The interface between the PtTi 3 layer and the rutile matrix is probably the seat of the polar phenomena, possibly involving a polar compound of the form PtTiO 3 . The electric field applied during the heat treating process serves to align the polar intermetallic layer for whatever defects are suitably oriented relative to the applied field. Careful examination of the arrangement of the microstructural defects over the extension of the region between the lead wires does not indicate any tendency for the applied field to influence the orientation of the planar defect structures. In accordance with another embodiment of this invention, fabricating Pt-doped TiO 2-x ceramic rectifiers is based on a tape casting method presently used to fabricate the ceramic material used in TiO 2 exhaust-gas-oxygen sensors. The major processing steps are outlined below and illustrated in FIGS. 3a, 3b, 3c and 3d. A tape 31 is formed by starting with TiO 2 powder and calcining at 1150° C. for 2 hours. The calcined powder is mized with water and ball milled for 16 hours. The TiO 2 dried powder is mixed with solvents and binder and again ball milled, deaired, and finally the ceramic slurry is metered onto a cellulose triacetate plastic sheet 32 to form a tape of ceramic about 0.020" thick. Relatively large area ceramic pieces 33, about 1 inch square, are cut from the plastic tape and fired at 1250° C. Platinum electrodes about 0.00005" thick are sputter deposited on the major faces of the ceramic piece. With the platinum electrodes on the major faces, the material is subjected to the heat treatment procedure given previously. After heat treatment, the 1 inch square piece 33 is sliced into small square wafers 34 of ceramic (FIG. 3c) lead wires are bonded to the Pt electrodes, and the ceramic wafer is packed in a conventional diode or transistor mounting structure (FIG. 3d). Various modifications and variations will no doubt occur to those skilled in the art. Useful devices may be achieved in ceramic oxides other than TiO 2 since there is some experimental evidence that Pt and Pd can form polar interfacial layers with oxides of other tetravalent metal atoms. Further, improvement in the performance of the Pt doped Tio 2-x rectifying devices is expected to be obtained by refining the processing in such a way that the ceramic has in its final condition most of its grains with the thin single layer defect structures illustrated in FIG. 2c. These and all other variations which basically rely on the teachings through which this disclosure has advanced the art are properly considered with the scope of this invention as defined by the appended claims.

This specification discloses a method of fabricating a titanium rectifier circuit element. A titanium dioxide main body is formed with a pair of spaced faces each of which having thereon a platinum electrode. A dc voltage is applied across this structure, heating the structure to a temperature of about 750°-850° C. In this temperature range, the titanium dioxide body is subjected to a cyclic sequence of exposures to oxidizing and reducing atmospheres. The final step includes cooling down the titanium dioxide body in the presence of a reducing atmosphere with an applied dc electric field.

BACKGROUND 1. Field of Invention The present invention relates generally to the field of telecommunication systems. More particularly the present invention relates to the field of reducing data quality degradation due to encoding/decoding. 2. Background of the Invention One of the key issues in wireless communications is quality of the service. For voice communications, one measure of quality is the performance of the speech handling systems. An ideal wireless system provides a communications path that is noise free and has high fidelity of reproduction of speech and music. Additionally, because of the preponderance of voice band data applications using modems, the same wireless communications path should ideally support the voice band modems in use on the wireline network. Unfortunately, this ideal cannot be obtained in commercially practical wireless communications systems that must balance cost and capacity against superb audio quality. Given that the service offered in traditional mobile telephony systems is to enable effective voice communications mainly carrying speech, the wireless speech transport mechanisms purposefully fall short of the ideal. In analog mobile systems the radio channel bandwidth allocation allows for a speech system, that using FM modulation, can transport a speech band from about 300 Hz to about 3,300 Hz. This is sufficient for a reasonably high fidelity communications system that handles speech, “music-on-hold,” and medium speed modem data. The analog system is good enough in its fidelity and reproduction capability that multiple cascaded analog connections produce negligible degradation. In fact, prior to the vast digitalization that has taken place, wireline telephony service providers using analog communications circuits could carry the same 300 to 3,300 Hz communications channel across continents and oceans while essentially retaining the quality. The most significant degradation in the analog systems is accumulated noise. This is the pops, crackles, and other perturbations that one traditionally notices. The advent of digital electronics has changed the nature of the communications channel. While a digital signal does not suffer from the accumulated noise impacts and can remain virtually pure no matter how far it is transported, there is a weak link in the chain of quality. To obtain a digital signal, the analog speech must be converted to a digital form. This conversion process, within the practical constraints of cost effective technology, introduces impairments (i.e., degradation) in the 300 to 3,330 Hz speech channel. The “high end” of digital telephony is considered to be the conversion of the analog to a digital signals at a rate of 64 kbps. As these signals are transported, there arises the need to convert the signals back to analog form. Often the signal is converted back to digital again. Each analog to digital conversion (and its counterpart digital to analog conversion) adds an additional amount of impairment to the original signal. In the case of the 64 kbps digital signal, approximately 8 tandem analog/digital conversions can be tolerated before the quality is reduced to unacceptable levels. In mobile communications, the driver for digital telephony has been increased capacity. To achieve additional capacity in the same channel bandwidth allocations previously used by analog FM systems, it is necessary to use an analog to digital conversion technique that encodes the speech at a rate much less than 64 kbps. As the number of bits per second is reduced, the impairments introduced by the analog to digital conversion and coding process become increasingly large. As encoding rates are reduced, the susceptibility of the payload to impairments in the transmission medium increases. Each information bit becomes more important since it now represents a larger fraction of the desirable information payload. Thus, degradation over a fixed bit error rate channel will increase with lower bit rate encoding schemes. For example, at an 8 kbps coding rate, more than one set of encoding and decoding leads to significant problems. At a 4 kbps coding rate, more than two sets of encoding and decoding produces a virtually unusable communications path. The issues are much the same for wireless mobile data (as opposed to wireless LANs). While certain quality requirements are different for data than voice, i.e., moderate delay is acceptable for data, but corruption of bit order or loss of bits is totally unacceptable, the issues described above are equally applicable. Data interworking may require rate adaptation, protocol conversion, error correction, etc. Often the interworking of disparate data networks requires treatment of the physical layer and also adaptation of the content, up to and including the presentation layer. This implies that one may need to address all seven layers of the traditional OSI data model for data gateways, a quantum leap from voice interworking which would generally only need treatment of the first two (or possibly three) layers of the OSI model. DEFINITIONS The term “transliteration,” as used herein means transforming a signal from one type of coding to another different type of coding. The term “vocoder” as used herein means a voice codec as is commonly used in telephony networks to convert analog voice data to digital data representative of the analog speech and digital-to-analog conversions on digital data representative of analog voice data to the analog data according to predetermined algorithms. As is well-known in the art vocoder algorithms differ in complexity and effective bit rate to achieve varying levels of quality of the voice data as it is subjected to conversions. SUMMARY OF THE INVENTION The present invention provides architectures for using vocoders that are designed to improve the quality of the speech that traverses through the architecture. A first preferred embodiment of the present invention is a modified “bypass” mode, in which the data is “massaged” prior to being sent. In conventional vocoder bypass, digital voice data can be sent through the base station and mobile switching center (“MSC”) and any intervening network elements without modification. However, the intervening network might impair the data in some way. According to the present invention, the data is massaged prior to being sent through the intervening network to mitigate the effect of this impairment on the data. A second preferred embodiment of the present invention is a “common inter-working facility” mode. According to the second preferred embodiment of the present invention, a “standard” vocoder format is defined. Prior to transmitting voice data to the receiving subscriber unit's MSC, it is converted to the standard format. The data is sent to the receiving mobile unit of the receiving subscriber unit's MSC, for conversion to whatever vocoder format the receiving subscriber unit normally uses. If the conversion is performed by the subscriber units, this embodiment can be combined with vocoder bypass to avoid conversions in the MSC. The standard format can be any arbitrary vocoder format. In a third preferred embodiment of the present invention, vocoder “impersonation” is used. In this embodiment, the digital voice data is converted to the receiving subscriber unit's vocoder format. The converted data is then sent to the receiving subscriber unit. If the conversion is performed by the sending subscriber unit, vocoder impersonation can be combined with vocoder bypass to avoid conversions in the MSC. A fourth preferred embodiment of the present invention uses vocoder “substitution.” In vocoder substitution, a vocoder format is selected. The selected vocoder format must be available in each of elements that the voice data passes through, specifically, the sending subscriber unit, the receiving subscriber unit, and their MSCs. The data is converted to the selected format and sent to the receiving mobile unit. Where the subscriber units perform the conversions, vocoder bypass can be used to avoid any conversions in the MSC. Which format to use depends on many factors, including which vocoder formats are being used, desired speech quality and processing capability of the subscriber units. The present invention provides for communication between the sending and receiving subscriber units to determine which vocoder format to use. In the preferred embodiment, this is done through messaging using the SS7 intelligent network associated with mobile telephony. Messages are sent between the sending and receiving subscriber units to determine which vocoder format to use. In some cases, that format may not be available to one or the other of the subscriber units. In that case, the required vocoder can be downloaded from a vocoder storage area. Alternatively, the decision can be made to perform all vocoding functions in the base station or MSC and not in the subscriber units. Another consideration affecting data quality is the particular route the data takes through the intervening network. For example, when using bypass, any non-conforming element in the intervening network will require additional decoding and encoding steps. As described above, these steps degrade the quality of the underlying transmitted voice signal. Using the common channel signaling provided by SS7, the MSC can assign intervening network elements to handle the call. That is, the present invention can configure the intervening network to minimize impairments to the underlying voice data being transmitted. Another configuration consideration is tandem order. Where cascaded encoding/decoding is required, the order is chosen so that the highest quality encoding/decodings are performed first. Further, the present invention describes the concept of a universal decoder. The universal decoder is preferably software or hardware configurable to implement any vocoder format. The universal vocoder is can be used to convert voice data to any desired vocoder format. In addition, in the receiving subscriber unit, the universal decoder can automatically determine the correct vocoder format. This can be done in a number of ways including a brute force method in which the incoming voice data is decoded against all vocoder formats in the universal decoder, and the best match is chosen. Preferably, the match is based on frame structure and error functions. Thus, one object of the present invention is to reduce or eliminate the degradation of voice quality due to encoding and decoding. Another object of the present invention is to use vocoder substitution to reduce degradation to voice data. Another object of the present invention is to use vocoder translation to reduce degradation to voice data. Another object of the present invention is to use vocoder bypass with data massaging to reduce degradation to voice data. Another object of the present invention is to use vocoder impersonation to reduce degradation to voice data. Another object of the present invention is to use vocoder substitution to reduce degradation to voice data. Another object of the present invention is to assign intervening elements over which to route voice data. Another object of the present invention is to apply a universal vocoder to reduce degradation to voice data. Another object of the present invention is to reduce degradation when wireline networks communicate with wireless networks. These and other objects of the present invention are described in greater detail in the detailed description of the invention, the appended drawings and the attached claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a system for transmitting data using vocoder bypass according to a first preferred embodiment of the present invention. FIG. 2 is a schematic diagram of a system using a massager to massage data to mitigate the effects of any intervening network elements. FIG. 3 is a schematic diagram of a system for transmitting data using a common interworking facility mode according to a second preferred embodiment of the present invention. FIG. 4 is a schematic diagram of a system for transmitting data using vocoder impersonation with bypass according to a third preferred embodiment of the present invention. FIG. 5 is a schematic diagram of a system for transmitting data using vocoder translation with bypass according to a fourth preferred embodiment of the present invention. FIG. 6 is a schematic diagram of a system for transmitting data using vocoder substitution with bypass according to a fifth preferred embodiment of the present invention. FIG. 7 is a flow chart illustrating a method for transmitting data according to the preferred embodiment of the present invention. FIG. 8A is a schematic diagram for a first preferred embodiment of a universal vocoder. FIG. 8B is a schematic diagram for a second preferred embodiment of a universal vocoder. FIG. 8C is a schematic diagram for a third preferred embodiment of a universal vocoder. FIG. 9 is a schematic diagram of a system for providing vocoder services using a service bureau according to another preferred embodiment of the present invention. FIG. 10 is a schematic diagram of a preferred embodiment of the present invention in which a route through an intervening network is chosen. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a system and method for improving speech quality in telecommunication systems. While the preferred embodiments of the present invention are described with respect to wireless telephony systems, there is no intent to limit the present invention to wireless telephony systems. Thus, the techniques described herein can be applied to any system in which data must be converted from one format to another, wherein the conversion process degrades the data. In general, the present invention is an architecture for transmitting voice data from a sending subscriber unit to a receiving subscriber unit. The subscriber units can be any devices capable of sending data, including for example telephony devices such as, wireline telephone, wireless telephones, personal computers, personal digital assistants (“PDAs”), pagers, etc. The receiving and sending devices can also be switches or base stations on which vocoders required for the present invention are implemented. The present invention allows the sending subscriber unit to transmit voice data to the receiving subscriber unit so as to minimize degradation on the voice signal due to the encoding and decoding that the voice data usually undergoes prior to reaching the receiving subscriber unit. The present invention provides this impairment mitigation primarily by reducing the number of encoding/decoding steps that must be performed. FIG. 1 is a schematic diagram of an architecture for a voice communication system according to the first preferred embodiment of the present invention. A sending subscriber unit 102 sends voice data to a receiving subscriber unit 104 . Sending subscriber unit 102 communicates through a base station 111 to a mobile switching center (MSC) 106 , and receiving subscriber unit 104 communicates through a base station 112 to an MSC 108 . Between MSCs 106 and 108 , in general, there can be intervening network elements 110 . In operation, the voice data is converted from analog data to digital data for transmission through the network shown in FIG. 1, by a vocoder 103 . The digital data is received by receiving subscriber unit 104 , where another vocoder 105 converts the received digital data back to analog, so that it can be played through a speaker on receiving subscriber unit 104 . In addition, MSC 106 has a vocoder 107 which is conventionally used to convert the data to Pulse Code Modulation (PCM) data (even when the data is already in PCM format) for transmission to MSC 108 . MSC 108 has a vocoder 109 , which converts the received PCM data to the format required by receiving subscriber unit 104 . In the first preferred embodiment, sending and receiving subscriber units 102 and 104 use the same vocoder format, such as vocoder format 1 . Because the sending and receiving subscriber units use the same vocoder format, no additional decoding/encoding steps need be performed by the vocoders located in MSC 106 and 108 . Consequently, vocoders 107 and 109 in MSCs 106 and 108 respectively are bypassed. That is, the voice data from sending subscriber unit 102 is transmitted directly to receiving subscriber unit 104 without being processed by vocoders 105 and 107 . MSCs 106 and 108 can be a single switch. In that case, vocoders 107 and 109 are on the same switch and can be the same vocoder. In addition, according to the first preferred embodiment of the present invention, the voice data is massaged prior to being transmitted through the intervening network so that any degrading effect on the data can be substantially eliminated. Thus, the data is modified in anticipation of its transmission through intervening network elements 110 . A schematic architecture for massaging the data is shown in FIG. 2 . Referring to FIG. 2, voice data is generated by vocoder 202 . The voice data is massaged in data massager 204 . The data is massaged according to transmission characteristics of the intervening network. An exemplary transmission characteristic is the “packaging” of the data. For example, the data is likely to be packaged differently depending on whether it is destined to be transmitted using circuit switching, ATM or IP. For example, bit robbing of the eighth bit is often performed on common T-carrier DSO systems to ensure a 56 kilobit per second bit rate. That is, the eighth bit of each data word is not sent. If the data massager of the present invention determines that it was sending data to a common T-carrier DSO, it would massage the data by populating all bits of each data word except that eighth bit. However, often that eighth bit is required by the intervening network elements, for example, as a status indicator. Consequently, in the preferred embodiment of the present invention, the eighth bit is set to the value that tells the intervening elements that the status is healthy, that is, there is no error. At the receiving end, the data is “de-massaged,” i.e. converted back to its original form by data de-massager 206 . For example, in the case of T-carrier DSO, the eighth bit is added back to the data. The de-massaged data is sent to vocoder 208 in the receiving subscriber unit for processing. For the bypass mode of operation, the vocoders can be located in the subscriber units 102 and 104 , base stations 111 and 112 or MSCs 106 and 108 . In addition, the vocoding functionality can be carried out by a service bureau. That is, the analog voice data is sent to third party service bureaus where it is encoded for subsequent transmission to the receiving subscriber unit. The service bureau is described in more detail below. FIG. 3 is a schematic diagram of an architecture for reducing encoding/decoding operations on the voice data according to the second preferred embodiment of the present invention. This embodiment is referred to as a “common inter-working facility” (CIWF). Referring to FIG. 3, a subscriber unit 302 initiates a telephone call to a subscriber unit 304 . Subscriber unit 302 converts the call to digital data using vocoder 305 . The digital data is sent to a base station 306 , which the subscriber unit 302 is in communication with, and on to an MSC 310 . In MSC 310 , the digital data is converted, or “transliterated” from vocoder format 1 to a common vocoder format, illustrated in FIG. 3 as vocoder format C. The transliteration is performed by CIWF transliterator 311 . Vocoder format C is a common vocoder format that can be used by all of the elements in the communication architecture shown in FIG. 3 . The digital data in vocoder format C is sent through intervening network elements 314 (if there are any) to an MSC 312 . In the general case, MSCs 310 and 312 can be a single MSC. A transliterator 313 in MSC 312 receives the digital data in common vocoder format C and outputs digital data in vocoder format X, the vocoder format to be sent to receiving subscriber unit 304 through base station 308 . Vocoder 315 converts the digital data from format X to analog for presentation to the speaker in subscriber unit 304 . Note that transliterators 311 and 313 can be implemented in the base station rather than in MSCs 310 and 312 . Further, vocoder format X can be, in the general case, vocoder format 1 . However, if this were the case, the bypass mode described above would be the preferable transmission mechanism. Which format to use can be determined in numerous ways as will be described below. An example where the CIWF mode might be used is in communication between vocoders adhering to the AMR and TDMA formats. The TDMA format is essentially a subset of the AMR format. Consequently, the vocoders can choose the TDMA format as the common format. Although, under this approach, the AMR voice quality is degraded to the level of the TDMA format, this degradation is likely to be far less than the degradation that would result from the additional encoding and decoding steps that would otherwise be required. The third embodiment of the present invention uses vocoder “impersonation.” As shown in FIG. 4, in this embodiment subscriber unit 402 desires to establish communication with subscriber unit 404 . Subscriber unit 402 has a vocoder 403 that can “impersonate” various vocoder formats 1 -N. Subscriber unit 404 has a vocoder 416 that uses vocoder format 2 . Vocoder format 2 is one of the vocoder formats subscriber unit 402 can impersonate. Subscriber unit 402 determines that it should use vocoder format 2 to digitize the voice data for transmission to subscriber unit 404 . The digitized data (in vocoder format 2 ) is sent to MSC 408 through base station 406 . A vocoder 409 in MSC 408 is bypassed as the subscriber units are communicating using the same vocoder format. The data is transmitted over any intervening network elements 410 to MSC 412 . Again a vocoder 413 in MSC 412 is bypassed because the subscribers units are communicating using the same vocoder format. The digitized data is then sent via base station 414 to subscriber unit 404 . The digitized data is converted to analog data so that it can be transmitted to a speaker on subscriber unit 404 by vocoder 416 . The vocoding step can also be performed in the base stations or MSCs. In the general case, MSCs 410 and 412 can be a single MSC. Vocoder impersonation can be combined with any other of the techniques described herein for reducing encoding/decoding steps. For example, if the vocoder cannot impersonate the receiving subscriber unit's vocoder format, the bypass technique cannot be used. However, another technique might be applicable. For example, it might be possible to use the CIWF mode described above. In this case, subscriber unit 402 sends digitized data according to its format and sends it to base station 406 , which sends the data to MSC 408 . A transliterator in either base station 406 or MSC 408 transliterates the digitized data to the common vocoder format. This data is sent through intervening elements 410 to MSC 412 , which sends it to base station 414 . A vocoder in either MSC 412 or base station 414 transliterates the transliterated data into a format that can be decoded by subscriber unit 404 . The data is sent to subscriber unit 404 where it is decoded by vocoder 416 . The fourth embodiment of the present invention uses vocoder “substitution.” As shown in FIG. 5 . Referring to FIG. 5, sending subscriber unit 502 desires to establish communications with receiving subscriber unit 504 . Vocoder 503 communicates with subscriber unit 502 using vocoder format 1 . Vocoder 505 in receiving subscriber unit 504 uses vocoder format X. In the embodiment shown in FIG. 5, the data is “translated” from vocoder format 1 to vocoder format A by transcoder 509 in MSC 508 . Vocoder format A is preferably chosen so as to minimize impairments when translating from vocoder format 1 to vocoder format A and from vocoder format A to vocoder format X. The translation is a digital-to-digital mapping. That is, there is no encoding or decoding required. Thus, there is no digital to analog conversion, followed by a subsequent digitization using vocoder format A. In operation, data is digitized in sending subscriber unit 502 by vocoder 503 , using vocoder format 1 . The digitized data is sent through a base station 506 to an MSC 508 . In MSC 508 , the digitized data is translated to vocoder format A by transcoder 509 using digital-to-digital translation. The translated data is sent through any intervening network elements 510 to MSC 512 . Although MSCs 510 and 512 are shown as separate MSCs, they can also be a single MSC. A transcoder 513 in MSC 512 translates the data from vocoder format A to vocoder format X, the format that receiving subscriber unit 504 can process. The data in vocoder format X is sent through a base station 514 to receiving subscriber unit 504 . The data in vocoder format X is converted to analog data by vocoder 505 . The “translation” mode of FIG. 5 differs from the CIWF mode described above with respect to FIG. 3 in that it is a dynamic configuration depending only on the elements in communication at the time that vocoder format A is chosen. In the CIWF described above, the common vocoder format C is chosen and fixed prior to system operation. An alternate implementation of the fourth embodiment of the present invention is shown in FIG. 6 . Referring to FIG. 6, sending subscriber unit 602 desires to establish communications with receiving subscriber unit 604 . Sending subscriber unit 602 and receiving subscriber unit 604 can substitute a vocoder format S for their normal vocoder formats. Thus, sending subscriber unit 602 can substitute a vocoder 603 that adheres to vocoder format S for its normal vocoder. Likewise, receiving subscriber unit 604 can substitute a vocoder 605 that adheres to vocoder format S for its normal vocoder. Analog voice data is digitized according to vocoder format S and sent through a base station 606 to an MSC 608 . MSC 608 has a vocoder 609 that can adhere to vocoder format S. If bypass, as described above, is available, MSC 608 passes the digitized data through any intervening network elements 610 to an MSC 612 . MSC 612 has a vocoder 613 that can adhere to the vocoder format S. Where the bypass mode of operation is available, MSC 612 passes the data on to base station 614 , which in turn, passes the data to subscriber unit 604 . A vocoder 605 in subscriber unit 604 converts the data to analog data for input to a speaker on receiving subscriber unit 604 . If the bypass mode is not available, then the digitized data is converted to analog data and digitized back to format S by vocoder 609 in MSC 608 . This data is then sent to MSC 612 . Likewise, if there is no bypass mode available, vocoder 613 converts the digital data to analog and then re-digitizes the data in vocoder format S. A method for practicing the present invention is illustrated in the flow diagram of FIG. 7 . Referring to FIG. 7, analog voice data is generated in step 702 in the sending subscriber unit. For example, the analog voice data is generated when a person speaks into a microphone located on the sending subscriber unit. In step 704 the vocoder format to use is determined. This determination can take place at several points. The sending subscribing unit can make the determination, the base station can make the determination or the MSC can make the determination. How the determinations are made is described in more detail below. After the vocoder format is determined, the analog voice data is digitized according to the selected vocoder format in step 706 . Steps 704 and 706 can be performed by the sending subscriber unit, the base station communicating with the sending subscriber unit, the MSC that sends the data, a combination of these elements, or a combination of these elements with any combination of the MSC that receives the data, the base station communicating with the receiving subscriber unit and/or the receiving subscriber unit. The digitized data is transmitted to the receiving subscriber unit through an MSC and a base station in step 708 . The data may also be transmitted through intervening elements in step 708 . The digital data is converted to analog data in step 710 . Step 710 can be performed by the MSC to which the data is sent, the base station communicating with the receiving subscriber unit or the receiving subscriber unit. The analog data is then input to a speaker in the receiving subscriber unit in step 712 . In operation, there are several ways for choosing which vocoder format to use according to the preferred embodiments of the present invention. One way of making this determination requires that the sending and receiving unit communicate their capabilities with one another. Such communication can occur over the SS7 network during call set-up. For example, using the short messaging service (SMS), the subscriber units can communicate to one another in 160 character messages to determine which vocoder format to use. The subscriber units decide between themselves which vocoder format to use. The choice will depend on which vocoder formats are available to the subscriber units, desired quality, air link bandwidth. In this mode of operation, the subscriber units would have to be able to impersonate other vocoders as described above. One advantage is that after the impersonation, the bypass mode will often be available. If they could not impersonate other vocoders, the subscriber units could default to CIWF or vocoder translation. If they determined that they used the same format, bypass would be the preferred method of data transmission. Alternatively the decoder choice can be made in the MSC or in the base stations. When there is only one MSC or base station, the MSC or base station polls the sending and receiving subscribing units to determine which vocoder formats they use. Depending on the formats, the MSC or base station can decide which vocoders to employ. For example, if the sending and receiving subscriber unit use the same vocoding format, the MSC or base station can simply bypass vocoding altogether as described above. If they differ, the MSC or base station determines the vocoder to use to impose the minimum impairment on the voice signal. If there are two MSCs or base stations, MSCs communicate with one another and their respective subscriber units to determine which of the above vocoding modes to employ, and which vocoding formats to use. Again, the decision on vocoding format depends on what is available to the subscriber units, MSCs and/or base stations as well as acceptable impairment levels. When vocoding decisions are performed by the MSCs or base stations, any of the above vocoding methods can be used. Rather than polling the subscriber units to determine the vocoding, the MSC or base station can alternatively determine the decoder formats by examining the decoder data using an automatic determination. Preferably, the automatic determination is made using known parameters of the decoded signal. For example, frame structure and/or error functions can be determined. Using knowledge of the frame structure and/or error functions, several vocoders can be tested to determine which produces the best data. The vocoder producing the best data is chosen as the vocoder to use. This automatic determination leads into another technique for making the vocoder determination. This technique is referred to as a “universal decoder.” A universal vocoder can impersonate any known vocoder. In addition, the universal vocoder preferably determines the format of the incoming vocoder data automatically. Alternatively, the universal vocoder can be sent information, as described above, instructing it which vocoder to use. The universal vocoders of the present invention can be implemented in subscriber units, base stations and MSCs. FIG. 8A is a schematic diagram of a first embodiment of a universal vocoder according to a preferred embodiment of the present invention. Vocoder data having an unknown format is presented to a universal vocoder 802 . Universal vocoder 802 comprises N vocoders 804 a - 804 n . Each of the N vocoders can process the incoming data according to a different vocoder format. Together, the N vocoders can preferably process any known vocoder format. Alternatively, any subset of vocoders representing a subset of the known vocoder formats can be used without limitation. The incoming data is processed by each of the N vocoders. The processed data is input to an analysis module 806 . Using various parameters, analysis module 806 determines which vocoders' output is the best, i.e., the most likely to be the correct vocoder to decode the unknown incoming data. This determination is made by determining frame size and/or processing error functions to determine which data is likely to be the correctly decoded data. Error functions analysis can be used in those vocoders that send error signals as their data. Analysis module 806 generates a select signal that triggers a switch or decoder to allow the decoded data corresponding to the most likely vocoder pass through as the output of universal vocoder 802 . Universal vocoder 802 can be implemented in hardware or software, as would be apparent to those skilled in the art. FIG. 8B is a schematic diagram of a second embodiment of a universal vocoder according to a preferred embodiment of the present invention. Referring to FIG. 8B, data having an unknown vocoder format is input to a universal vocoder 820 . Universal vocoder 820 comprises a reconfigurable vocoder 824 . Reconfigurable vocoder 824 can be firmware, for example, a field programmable gate array or software, for example, or a data structure. A vocoder memory 822 stores vocoder implementations to process all known vocoder formats. Alternatively, any subset of known vocoder implementation can be stored in vocoder memory 822 . In operation, an analysis module 826 causes each vocoder implementation to be implemented in turn in reconfigurable vocoder 824 . Analysis module 826 then analyzes the vocoder output and generates a score that is stored. The score is based on the quality of the output. As described above, the quality of the output can be determined by looking at frame structure and/or error functions. After all of the vocoder implementations stored in vocoder memory 822 and scores are generated, analysis module 826 generates a select signal to vocoder memory 822 . The select signal corresponds to the vocoder implementation having the highest score. Vocoder memory 822 stores the vocoder implementation corresponding to the select signal in reconfigurable vocoder 824 . The vocoded output is decoded data. The select signal also toggles a mode switch. The mode switch indicates that reconfigurable vocoder 824 is in the analysis mode or the output mode. Reconfigurable vocoder 824 is in analysis mode when the vocoder format is being determined. Reconfigurable vocoder 824 is in output mode after the format has been determined and it generates decoded data. A third embodiment of a universal vocoder according to a preferred embodiment of the present invention is illustrated schematically in FIG. 8 C. Referring to FIG. 8C, universal vocoder 850 comprises a vocoder bank 852 having N vocoders. Preferably the N vocoders correspond to all known vocoder formats. In an alternate embodiment, any subset of vocoder formats can be implemented. In addition, universal vocoder 850 includes a bank of M reconfigurable vocoders. M can be from 1 to any number fitting within the constraints of the system on which the universal vocoder of the present invention is implemented. The M vocoders allow up to M vocoded streams to be decoded simultaneously. In operation, unknown data is simultaneously submitted to the bank of N vocoders in vocoder bank 852 . The outputs of the N vocoders is sent to an analysis module 856 . Using the frame structure or error function as a metric as described above, analysis module 856 determines the most likely vocoder format to decode the unknown data. Preferably, analysis module 856 generates a select signal corresponding to the vocoder determined to be the best. The select signal is input to a vocoder memory 858 to output vocoder implementation data corresponding the best vocoder format for the unknown data to the bank of M reconfigurable vocoders in reconfigurable vocoder bank 854 . This vocoder implementation data is used to configure the next available reconfigurable vocoder in reconfigurable vocoder bank 854 . An up/down counter (either hardware or software depending on implementation) can be used to track the next available reconfigurable vocoder to be used. Reconfigurable vocoders are put back into the available vocoder pool when a call completes. The universal vocoders described above can also process data on the sending side according to any of the known vocoder formats or any subset thereof. This is accomplished by using the select signal to select the desired vocoder format. In one embodiment, a universal vocoder is located in the sending subscriber unit and the select signal is generated by the base station or MSC. Several of the embodiments of the present invention described above require a vocoder configuration that is able to process data in any of a number of vocoder formats. The universal vocoder is one embodiment for doing this. When the vocoder is in the base station or in the MSC, the universal vocoder concept or bank of vocoders adhering to the known vocoder formats or subset thereof is satisfactory for accomplishing the task. However, for vocoders located in subscriber units, memory constraints can eliminate these possibilities for having a vocoder capable of handling a plurality of formats. To overcome these difficulties, the required vocoder implementation can be downloaded to the subscriber unit when it is required. That is, the subscriber unit communicates with the base station to have the vocoder implementation downloaded to it. The downloaded vocoder implementation configures programmable logic or contains software to perform vocoding according to the required format. The bases station can store the vocoder implementations or obtain them from the MSC. In one embodiment of the present invention, a service bureau is established that performs the encoding and decoding service for its customers. Referring to FIG. 9, a sending subscriber unit 902 desires to communicate with a receiving subscriber unit 904 . Subscriber unit 902 digitizes the voice data to be sent using its resident vocoder. The digitized data is forwarded to an MSC 908 through base station 906 . MSC 908 determines if transliteration is required as described above. If transliteration is required, the data is transferred to service bureau 910 . Service bureau 910 performs any required transliteration and forwards the transliterated data to MSC 912 . If transliteration is not required, the digitized data is sent to MSC 912 through any intervening network 909 . MSC 912 forwards the data to base station 914 , which forwards it to receiving subscriber unit 904 . The digitized data is converted back to analog using vocoder 905 . In alternative embodiments, the digitized voice data is sent by subscriber unit 902 or base station 906 to service bureau 910 . In addition, in alternate embodiments, service bureau 910 can send the transliterated data to base station 914 or receiving subscriber unit 904 . In the preferred embodiment, service bureau 910 is instructed which transliteration is required by any of the elements in the communication path, namely sending subscriber unit 902 , receiving subscriber unit 904 , base stations 906 or 914 , or MSC 908 or 912 . As described above, MSCs 908 and 912 can be a single MSC. Another aspect of the present invention is the ability to choose network architectures for transmission. Referring to FIG. 10, suppose that MSC 1002 , servicing a sending subscriber unit (not shown) is sending data to MSC 1004 servicing a receiving subscriber unit (not shown). Suppose further that the sending and receiving subscribing units use the same vocoder format. Because the sending and receiving subscribing units use the same format, vocoder bypass is the preferred transmission technique. MSC 1002 sends the data through an intervening network 1005 . Intervening network 1005 contains intervening network elements (NEs) 1006 , 1008 , 1010 , 1012 , 1014 and 1016 . Therefore the data travels through one of several paths containing a combination of the intervening network elements. Some of the paths might require transliteration or perform undesired transformations of the data, for example bit robbing as described above, while others may not. For example, suppose that the path from MSC 1012 through intervening network elements 1010 and 1016 requires bit robbing of the data, while the path through intervening network elements 1006 and 1014 does not. According to the preferred embodiment of the present invention, MSC 1002 negotiates with the intervening network 1005 to ensure that the path for the data is through intervening network elements 1006 and 1014 . Thus, a preferred embodiment of the present invention may include the ability to negotiate with an intervening network to route around non-conforming elements to minimize encoding/decoding steps. In addition, the present invention can route to minimize voice quality degradation when transliteration is required. An additional consideration applies to transliterations that require cascaded conversions, that is, that require more than one conversion of the same data. In such cascaded conversions, the order of the conversion is important. Preferably, the conversion that degrades the data the least is performed first, followed by the next least impact conversion and so on until the entire required cascade is complete. Performing the conversions in the order of least degradation to most degradation preserves the data to the extent possible through the conversion chain. As described above, to communicate with one another, the data from vocoders have different formats must be transliterated in some manner. Various architectures for performing this were presented above. Tables 1-5 present the preferred conversion architecture for conversion between particular formats. Tables 1-5 are not meant to be exhaustive, and those skilled in the art will find alternate and additional conversions that can be applied using present invention. TABLE 1 Assignment of preferred interworking solutions. ANA- FROM/TO LOG TDMA - 3X TDMA - 6X TDMA - DSI Analog 0 0 0 0 TDMA - 3X 0 1 2, 3B 2, 3B TDMA - 6X 0 2, 3A, 3B 1 2, 3B, 3C TDMA - DSI 0 2, 3A, 3B 2, 3A, 3B, 1 3C CDMA - 8 kbps 0 2, 3B 2, 3B 2, 3B CDMA - 13 kbps 0 2, 3B 2, 3B 2, 3B CDMA - EVRC 0 2, 3B 2, 3B 2, 3B PCS - 32 kbps 0 0 0 0 PCS - 16 kbps 0 2, 3B 2, 3B 2, 3B PCS - 8 kbps 0 2, 3B 2, 3B 2, 3B GSM - FULL 0 2, 3B 2, 3B 2, 3B GSM - HALF 0 2, 3B 2, 3B 2, 3B DCS - 1800 0 2, 3B 2, 3B 2, 3B ESMR 0 2, 3B 2, 3B 2, 3B LEO Satellite 0 2, 3B 2, 3B 2, 3B INMARSAT 0 2, 3B 2, 3B 2, 3B TABLE 2 Assignment of preferred interworking solutions. CDMA - CDMA - CDMA - FROM/TO 8 kbps 13 kbps EVRC Analog 0 0 0 TDMA - 3X 2, 3B 2, 3B 2, 3B TDMA - 6X 2, 3B 2, 3B 2, 3B TDMA - DSI 2, 3B 2, 3B 2, 3B CDMA - 8 kbps 1 2, 3B 2, 3B CDMA - 13 kbps 2, 3A, 3B 1 2, 3B CDMA - EVRC 2, 3B 2, 3B 1 PCS - 32 kbps 0 0 0 PCS - 16 kbps 2, 3B 2, 3B 2, 3B PCS - 8 kbps 2, 3B 2, 3B 2, 3B GSM - FULL 2, 3B 2, 3B 2, 3B GSM - HALF 2, 3B 2, 3B 2, 3B DCS - 1800 2, 3B 2, 3B 2, 3B ESMR 2, 3B 2, 3B 2, 3B LEO Satellite 2, 3B, * 2, 3B, * 2, 3B, * INMARSAT 2, 3B 2, 3B 2, 3B TABLE 3 Assignment of preferred interworking solutions. FROM/TO PCS - 32 kbps PCS - 16 kbps PCS - 8 kbps Analog 0 0 0 TDMA - 3X 0, 2, 3B 2, 3B 2, 3B TDMA - 6X 0, 2, 3B 2, 3B 2, 3B TDMA - DSI 0, 2, 3B 2, 3B 2, 3B CDMA - 8 kbps 0, 2, 3B 2, 3B 2, 3B CDMA - 13 kbps 0, 2, 3B 2, 3B 2, 3B CDMA - EVRC 0, 2, 3B 2, 3B 2, 3B PCS - 32 kbps 0, 1 0 0 PCS - 16 kbps 0, 2, 3B 0, 1 2, 3B PCS - 8 kbps 0, 2, 3B 2, 3B 1 GSM - FULL 0 2, 3B 2, 3B GSM - HALF 0 2, 3B 2, 3B DCS - 1800 0 2, 3B 2, 3B ESMR 0 2, 3B 2, 3B LEO Satellite 0 2, 3B 2, 3B INMARSAT 0 2, 3B 2, 3B TABLE 4 Assignment of preferred interworking solutions. FROM/TO GSM - FULL GSM - HALF DCS - 1800 Analog 0 0 0 TDMA - 3X 0, 2, 3B 2, 3B 2, 3B TDMA - 6X 0, 2, 3B 2, 3B 2, 3B TDMA - DSI 0, 2, 3B 2, 3B 2, 3B CDMA - 8 kbps 0, 2, 3B 2, 3B 2, 3B CDMA - 13 kbps 0, 2, 3B 2, 3B 2, 3B CDMA - EVRC 0, 2, 3B 2, 3B 2, 3B PCS - 32 kbps 0 0 0 PCS - 16 kbps 2, 3B 2, 3B 2, 3B PCS - 8 kbps 2, 3B 2, 3B 2, 3B GSM - FULL 1 2, 3B 1 GSM - HALF 2, 3A, 3B 1 2, 3A, 3B DCS - 1800 1 2, 3B 1 ESMR 2, 3B 2, 3B 2, 3B LEO Satellite 2, 3B 2, 3B 2, 3B INMARSAT 2, 3B 2, 3B 2, 3B TABLE 5 Assignment of preferred interworking solutions. LEO FROM/TO ESMR SATELLITE INMARSAT Analog 0 0 0 TDMA - 3X 2, 3B 2, 3B 2, 3B TDMA - 6X 2, 3B 2, 3B 2, 3B TDMA - DSI 2, 3B 2, 3B 2, 3B CDMA - 8 kbps 2, 3B 2, 3B, * 2, 3B CDMA - 13 kbps 2, 3B 2, 3B, * 2, 3B CDMA - EVRC 2, 3B 2, 3B, * 2, 3B PCS - 32 kbps 0 0 0 PCS - 16 kbps 2, 3B 2, 3B 2, 3B PCS - 8 kbps 2, 3B 2, 3B 2, 3B GSM - FULL 2, 3B 2, 3B 2, 3B GSM - HALF 2, 3B 2, 3B 2, 3B DCS - 1800 2, 3B 2, 3B 2, 3B ESMR 1 2, 3B 2, 3B LEO Satellite 2, 3B 1 2, 3B INMARSAT 2, 3B 2, 3B 1 The following definitions apply to Tables 1-5. 0 —None Required 1 —Vocoder Bypass 2 —Common Inter-Working Facility 3 A—Vocoder Impersonation 3 B—Vocoder Translation 3 C—Vocoder Substitution. The following notes apply to Tables 1-5: PCS 32 kbps, PCS 16 kbps, and PCS 8 kbps are definitions of typical coding rates that may be used by the numerous technologies being considered for 2 GHz PCS. They are representative labels and no forward/backward compatabilities are implied. Each should be considered as a stand-alone technology. PCS 32 kbps is considered to be of such a quality that is equivalent to analog for interworking purposes. PCS 16 kbps is considered to be of a quality level that interworking to anything of equal or greater quality is equivalent to interworking with analog. Certain of the LEO satellite systems may utilize vocoders common to terrestrial CDMA systems. For those cases solutions are 1 , 2 , 3 A, 3 B. Though described above with respect to wireless voice, the present invention applies to transmitting wireline voice as well. Wireline voice is increasingly transmitted over computer networks as data. Consequently, wireline service providers will face similar issues to those faced in by wireless service providers described above. Moreover, the vocoders being used by wireline service providers are not compatible with the vocoders used by wireless service providers. Consequently, the techniques described above will be of vital importance in connecting telephony traffic between wireless and wireline service providers. The foregoing disclosure of 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 obvious 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.

Transliteration architectures reduce the number of encoding/decoding steps required to transmit telephony data. The reduction of encoding/decoding steps improves the quality of the transmitted data due to the avoidance of the significant adverse effects on the data from encoding and decoding. The reduction is accomplished using a transliterator device or through bypassing the transliterator device. A universal vocoder is proposed that allows the vocoding element to encode or decode data according to any desired vocoder format. Network routing considerations allow optimal decisions on which vocoder formats to use. Network routing decisions can be made based on vocoder formats used.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser. No. 12/794,429 filed Jun. 4, 2010, which is a continuation of U.S. application Ser. No. 11/399,492 filed Apr. 7, 2006 which issued as U.S. Pat. No. 7,758,223 on Jul. 20, 2010. U.S. Pat. No. 7,758,223 claims priority to Japanese Patent Application No. 2005-112339 filed Apr. 8, 2005, Japanese Patent Application No. 2005-221571 filed Jul. 29, 2005, Japanese Patent Application No. 2005-221688 filed Jul. 29, 2005; and Japanese Patent Application No. 2005-371406 filed Dec. 26, 2005. The entire contents of all of the applications mentioned above are incorporated herein by reference. BACKGROUND [0002] 1. Field [0003] Aspects described herein relate to a lamp using a semiconductor element like a light-emitting diode as a light source, and more particularly a structure for efficiently radiating the heat generated by a light source during lighting of a lamp. [0004] 2. Description of the Related Art [0005] A light-emitting diode is well known as a light source for a lamp compatible with an incandescent lamp. The output of the light-emitting diode is lowered and the life is reduced, as the temperature is increased. Therefore, it is necessary to control the increase of the temperature of the light-emitting diode in the lamp using the light-emitting diode as the light source. [0006] For example, Jpn. Pat. Appln. KOKAI Publication No. 2001-243809 discloses an LED lamp, which prevents overheat of a light-emitting diode by increasing the heat radiation of the light-emitting diode. The conventional LED lamp is provided with a spherical body, a metal substrate, and light-emitting diodes. The spherical body is composed of a metallic radiator having a base at one end and an opening at the other end, and a translucent cover. The metallic radiator has a shape spreading from one end to the other end like a bugle. [0007] The metal substrate is fixed to the opening of the metallic radiator through a high heat conductivity member having electrical insulation. The light-emitting diode is supported by the metal substrate and covered by the translucent cover. [0008] The heat generated by the light-emitting diode during lighting of the LED lamp is transmitted from the metal substrate to the metallic radiator through the high heat conductivity member. The heat transmitted to the metallic radiator is radiated to the atmosphere from the peripheral surface of the metallic radiator. This prevents overheat of the light-emitting diode, and increases the luminous efficiency of the LED lamp. [0009] According to the LED lamp disclosed by the published Japanese patent applications, the metallic radiator to radiate the heat of the light-emitting diode and the metal substrate to mount the light-emitting diode are different components. In this structure, though the metal substrate and the metallic radiator are connected through the high heat conductivity member, it is unavoidable to generate a thermal resistance in a joint of the metal substrate and the metallic radiator. Thus, the conduction of heat between the metal substrate and the metallic radiator disturbed, and the heat of the light-emitting diode cannot be efficiently transmitted from the metal substrate to the metallic radiator. There is a point to be improved to control the temperature increase of the light-emitting diode. [0010] Moreover, in the above-described LED lamp, a lighting circuit to light the light-emitting diode is an indispensable component. When the lighting circuit is incorporated in the LED lamp, it is requested that the size of the LED lamp is not increased by the lighting circuit. It is also known that when the temperature of the lighting circuit is increased, the reliability of the circuit operation is decreased and the life is reduced. Therefore, it is essential to prevent overheat of the lighting circuit when the lighting circuit is incorporated in the LED lamp. [0011] The above-mentioned published Japanese patent applications do not describe about the lighting circuit. The LED lamps disclosed in these applications do not satisfy the demand for preventing the large size of the LED lamp and overheat of the lighting circuit. BRIEF DESCRIPTION OF THE DRAWINGS [0012] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. [0013] FIG. 1 is a perspective view of a lamp according to a first embodiment of the present invention; [0014] FIG. 2 is a sectional view of the lamp according to the first embodiment of the present invention; [0015] FIG. 3 is a sectional view of the first embodiment of the present invention, with a base, an outer shell and a translucent cover separated; [0016] FIG. 4 is a sectional view taken along line F 4 -F 4 of FIG. 2 ; [0017] FIG. 5 is a sectional view taken along line F 5 -F 5 of FIG. 2 ; [0018] FIG. 6 is a perspective view of a lamp according to a second embodiment of the present invention; [0019] FIG. 7 is a sectional view of the lamp according to the second embodiment of the present invention; [0020] FIG. 8 is a sectional view of a lamp according to a third embodiment of the present invention; [0021] FIG. 9 is a sectional view of a lamp according to a fourth embodiment of the present invention; [0022] FIG. 10 is a sectional view of the lamp according to the fourth embodiment of the present invention, with a base, an outer shell and a translucent cover separated; [0023] FIG. 11 is a sectional view taken along line F 11 -F 11 of FIG. 9 ; [0024] FIG. 12 is a sectional view of a lamp according to a fifth embodiment of the present invention; [0025] FIG. 13 is a sectional view of a lamp according to a sixth embodiment of the present invention; [0026] FIG. 14 is a sectional view taken along line F 14 -F 14 of FIG. 13 ; [0027] FIG. 15 is a sectional view showing a positional relationship between a lead wire and an insulating cylinder in a sixth embodiment of the present invention; [0028] FIG. 16 is a front view showing a positional relationship between a wiring board to support a light-emitting diode and a light source support in a sixth embodiment of the present invention; [0029] FIG. 17 is a plan view of an insulating material used in the sixth embodiment of the present invention; [0030] FIG. 18 is a sectional view taken along line F 18 -F 18 of FIG. 17 ; [0031] FIG. 19 is a sectional view taken along line F 19 -F 19 of FIG. 17 ; [0032] FIG. 20 is a perspective view of the insulating cylinder used in the sixth embodiment of the present invention; [0033] FIG. 21 is a sectional view of a lamp according to a seventh embodiment of the present invention; [0034] FIG. 22 is a sectional view showing a positional relationship among a light source support of an outer shell, a light source, a light source cover and a holder in the seventh embodiment of the present invention; [0035] FIG. 23 is a sectional view showing a positional relationship among the light source cover, the holder and a heat shielding cover in the seventh embodiment of the present invention; [0036] FIG. 24 is an exploded perspective view showing a positional relationship among the outer shell, a heat conduction sheet and the light source in the seventh embodiment of the present invention; [0037] FIG. 25 is a perspective view of a separated light source cover of the seventh embodiment of the present invention; [0038] FIG. 26 is a sectional view of a lamp according to an eighth embodiment of the present invention; [0039] FIG. 27 is a plan view of the lamp according to the eighth embodiment of the present invention; [0040] FIG. 28 is a sectional view of a lamp according to a ninth embodiment of the present invention; and [0041] FIG. 29 is a plan view of the lamp according to the ninth embodiment of the present invention. DETAILED DESCRIPTION [0042] A first embodiment of the present invention will be explained hereinafter with reference to FIG. 1 to FIG. 5 . [0043] FIG. 1 and FIG. 2 show a bulb-type lamp 1 compatible with an incandescent lamp. The lamp 1 includes an outer shell 2 , a light source 3 , a translucent cover 4 , a lighting circuit 5 , an insulating member 6 , and a base 7 . [0044] The outer shell 2 is made of metallic material such as aluminum with excellent heat conductivity. As shown in FIG. 2 and FIG. 3 , the outer shell 2 has a peripheral wall 8 and an end wall 9 . The peripheral wall 8 and the end wall 9 are formed integrally. The peripheral wall 8 is cylindrical. The outer circumference of the peripheral wall 8 is a heat radiating surface 10 exposed outside the lamp 1 . The heat radiating surface 10 is tapered with the outside diameter decreased gradually from one end to the other end along the axial direction of the peripheral wall 8 . [0045] The end wall 9 closes one end of the peripheral wall 8 . The end wall 9 forms a circular plate light source support 11 . The light source support 11 has a flat supporting surface 11 a exposed outside the outer shell 2 . [0046] In the first embodiment, the heat radiating surface 10 of the outer shell 2 may be knurled and stain finished. This can increase the area of the heat radiating surface 10 . The heat radiating surface 10 may be coated with a protection film to prevent rusting. If a black protection film is coated, the efficiency of heat radiation from the heat radiating surface 10 to the atmosphere is increased. [0047] As shown in FIG. 2 and FIG. 3 , the outer shell 2 has a receptacle 12 . The receptacle 12 is defined by a space surrounded by the peripheral wall 8 and the end wall 9 , and positioned inside the heat radiating surface 10 . The receptacle 12 has an open end 12 a opposite to the end wall 9 . The open end 12 a is positioned at the other end of the peripheral wall 8 . [0048] The peripheral wall 8 has an inner peripheral surface exposed to the receptacle 12 . An engaging groove 8 a is formed on the inner peripheral surface. The engaging groove 8 a is positioned at the open end 12 a of the receptacle 12 , and continued in the circumferential direction of the peripheral wall 8 . A recession 14 is formed in the outer circumference of the end wall 9 . The recession 14 is circular surrounding the light source support 11 , and opened outward of the outer shell 2 . [0049] As shown in FIG. 2 to FIG. 4 , the light source support 11 has one screw hole 15 and a pair of through holes 16 a and 16 b. The screw hole 15 is positioned at the center of the light source support 11 . The through holes 16 a and 16 b are positioned parallel to each other on both sides of the screw hole 15 . One end of the screw hole 15 and the ends of the through holes 16 a and 16 b are opened to the supporting surface 11 a of the light source support 11 . The other end of the screw hole 15 and the other ends of the through holes 16 a and 16 b are opened to the receptacle 12 . [0050] As shown in FIG. 4 and FIG. 5 , the light source 3 includes four light-emitting diodes 18 shaped like a chip, for example. The light-emitting diodes 18 are an example of a point source of light, and mounted in two lines on a circular wiring board 19 . The wiring board 19 has an insulating substrate 20 . The insulating substrate 20 has a first surface 20 a and a second surface 20 b. The second surface 20 b is positioned on the opposite side of the first surface 20 a . [0051] A pattern layer 21 and a resist layer 22 are stacked on the first surface 20 a of the insulating substrate 20 . The pattern layer 21 is made of metal foil such as copper. The resist layer 22 covers the pattern layer 21 . A thermal diffusion layer 23 and a resist layer 24 are stacked on the second surface 20 b of the insulating substrate 20 . The thermal diffusion layer 23 is made of metal foil with excellent heat conductivity such as an alloy. The thermal diffusion layer 23 is thicker than the pattern layer 21 to ensure heat capacity. As shown in FIG. 5 , the thermal diffusion layer 23 is divided into four areas 23 a , 23 b , 23 c and 23 d . The areas 23 a , 23 b , 23 c and 23 d are separated, and correspond to the mounting positions of the light-emitting diodes 18 . The resist layer 24 covers the thermal diffusion layer 23 . The light-emitting diodes 18 are mounted on the first surface 20 a of the insulating substrate 20 , and electrically connected to the pattern layer 21 . [0052] As the wiring board 19 , a pattern layer, a thermal diffusion layer and a resist layer may be stacked on a metal substrate with excellent heat conductivity. However, considering the cost, it is desirable to use a resin substrate made of epoxy resin mixed with glass powder as the insulating substrate 20 , and to stack a pattern layer, a thermal diffusion layer and a resist layer on the resin substrate. [0053] The wiring board 19 is stacked on the light source support 11 with the thermal diffusion layer 23 faced to the supporting surface 11 a of the light source support 11 . The wiring board 19 is fixed to the light source support 11 through a screw 26 . The screw 26 is inserted into the screw hole 15 penetrating the center of the wiring board 19 . With this insertion of the screw, the wiring board 19 is fixed tightly to the supporting surface 11 a of the light source support 11 , and the wiring board 19 is thermally connected to the light source support 11 . [0054] Therefore, the heat generated by the light-emitting diode 18 is transmitted from the insulating substrate 20 to the thermal diffusion layer 23 , and diffused widely to every corner of the thermal diffusion layer 23 . The heat diffused to the heat diffusion layer 23 is transmitted to the light source support 11 through the resist layer 24 . [0055] According to the first embodiment, a heat conduction path from the wiring board 19 to the supporting surface 11 a is formed in the light source support 11 of the outer shell 2 . To control the thermal resistance of the heat conduction path, it is desirable to fill a heat-conducting substance consisting mainly of silicon, such as grease between the wiring board 19 and the supporting surface 11 a. [0056] The translucent cover 4 is a globe made of synthetic resin, for example, and is formed spherical having an opening 4 a at one end. The translucent cover 4 is held by the outer shell 2 by fitting an edge 4 b defining the opening 4 a into the recession 14 of the outer shell 2 . The translucent cover 4 hides the light source support 11 , light-emitting diodes 18 and wiring board 19 . Therefore, the light-emitting diodes 18 are faced to the inside surface of the translucent cover 4 . [0057] The lighting circuit 5 is used to light up the light-emitting diodes 18 , and unified as one module. As shown in FIG. 2 , the lighting circuit 5 has a wiring board 28 and circuit components 29 . The wiring board 28 has a first surface 28 a and a second surface 28 b positioned on the opposite side of the first surface 28 a . The circuit components 29 are mounted on the first surface 28 a of the wiring board 28 . The circuit components 29 have lead terminals. The lead terminals are soldered to conductor patterns (not shown) printed on the wiring bard 28 , penetrating through the wiring board 28 . [0058] The lighting circuit is housed in the receptacle 12 of the outer shell 2 . The lighting circuit 5 has lead wires 30 a and 30 b electrically connected to the light-emitting diodes 18 , and a lead wire (not shown) electrically connected to the base 7 . The lead wires 30 a and 30 b are led to the wiring board 19 , penetrating through the through holes 16 a and 16 b formed on the end wall 9 . The lead wires 30 a and 30 b are connected to the pattern layer 21 of the wiring board 19 by means of soldering. Therefore, as shown in FIG. 2 , when the translucent cover 4 is directed to the lamp 1 located on the outer shell 2 , the lighting circuit 5 is suspended from the light support 11 by the lead wires 30 a and 30 b. [0059] The insulating member 6 is an example of insulating layer for electrically insulating between the outer shell 2 and the lighting circuit 5 . The insulating member 6 is a molding using synthetic resin material, such as polybutylene terephthalate. As shown in FIG. 2 , the insulating member 6 is cup-shaped having a cylindrical peripheral wall 32 a and a closed wall 32 b closing one end of the peripheral wall 32 a . The closed wall 32 b has a pair of through holes 33 a and 33 b to pass the lead wires 30 a and 30 b . The axial length A of the insulating member 6 is shorter than the axial length B from the light source support 11 to the engaging groove 8 a of the outer shell 2 . [0060] The insulating member 6 is fit in the receptacle 12 through the open end 12 a . Therefore, the peripheral wall 32 a of the insulating member 6 covers the internal circumference of the peripheral wall 8 of the outer shell 2 , and the closed wall 32 b of the insulating member 6 covers the inside surface of the end wall 9 of the outer shell 2 . The insulating member 6 partitions the outer shell 2 and the lighting circuit 5 . [0061] The base 7 is used to supply a current to the lighting circuit 5 . The base 7 has a metal base shell 35 , and a connecting member 36 fixed to the base shell 35 . The base shell 35 is removably screwed into a lamp socket of a not-shown light fixture. The connecting member 36 is a molding using synthetic resin material, such as polybutylene terephthalate, and has electrical insulation. The connecting member 36 has a peripheral surface 36 a , which is formed to have a cylindrical hollow and curved circularly. [0062] As shown in FIG. 2 , the connecting member 36 has a distal end 37 to fit in the inside of the open end 12 a of the receptacle 12 . The distal end 37 has an engaging projection 38 on the peripheral surface. The engaging projection 38 engages with the engaging groove 8 a when the distal end 37 is fit inside the open end 12 a . By this engagement, the outer shell 2 and the base 7 are coaxially connected. The connecting member 36 is interposed between the base shell 35 and the outer shell 2 , insulating them electrically and thermally. [0063] In the state that the connecting member 36 is connected to the outer shell 2 , the peripheral surface 36 a of the connecting member 36 is continued to the heat radiating surface 10 of the outer shell 2 . A step 39 is formed in the base of the distal end 37 . The step 39 has a flat surface, which is continued in the circumferential direction of the connecting member 36 , and extending in the radial direction of the connecting member 36 . The step 39 butts against the open end 12 a , when the distal end 37 of the connecting member 36 is inserted into the open end 12 a of the receptacle 12 . This controls the insertion depth of the distal end 37 of the connecting member 36 into the receptacle 12 . [0064] As the insertion depth of the distal end 37 is controlled, a space S is generated between the distal end 37 of the connecting member 36 and the peripheral wall 32 a of the insulating member 6 . The existence of the space S prevents interference of the distal end 37 with the insulating member 6 before the engaging projection 38 engages with the engaging groove 8 a . In other words, Failure in engagement between the engaging projection 38 and the engaging groove 8 a caused by a dimensional tolerance of the connecting member 36 and outer shell 2 is prevented. Therefore, the base 7 can be surely connected to the open end 12 a of the receptacle 12 . [0065] In the lamp 1 of the first embodiment, when the lamp 1 is lit, the light-emitting diodes 18 are heated. The light-emitting diodes 18 are cooled in the following process, in addition to the cooling by conviction of the air generated within the translucent cover 4 . [0066] The heat of the light-emitting diodes 18 are transmitted to the light source support 11 of the outer shell 2 through the wiring board 19 . The heat transmitted to the light source support 11 is transmitted from the end wall 9 to the heat radiating surface 10 through the peripheral wall 8 , and radiated to the outside of the lamp 1 through the heat radiating surface 10 . [0067] The light source support 11 receiving the heat of the light-emitting diodes 18 is formed integrally with the peripheral wall 8 having the heat radiating surface 10 . There is no joint to disturb the conduction of heat on the heat conduction path from the light source support 11 to the heat radiating surface 10 , and the thermal resistance of the heat conduction path is decreased. Therefore, the heat of the light-emitting diodes 18 transmitted to the light source support 11 can be efficiently escaped to the heat radiating surface 10 . [0068] In addition, in the first embodiment, the circular recession 14 surrounding the light source support 11 is formed in the end wall 9 of the outer shell 2 , and the recession 14 is opened outward of the outer shell 2 . The existence of the recession 14 increases the surface area of the outer shell 2 , and increases the amount of heat radiation from the outer shell 2 though the shape of the outer shell 2 is restricted by the appearance of the lamp 1 . [0069] As a result, the cooling performance of the light-emitting diodes 18 is increased, and overheat of the light-emitting diodes 18 is prevented. Therefore, the decrease of the light-emitting efficiency of the light-emitting diodes 18 can be controlled, and the life of the light-emitting diodes 18 can be made long. [0070] Moreover, the light-emitting diodes 18 are mounted on the wiring board 19 having the thermal diffusion layer 23 , and the heat generated by the light-emitting diodes 18 are diffused to every corner of the wiring board 19 through the thermal diffusion layer 23 of the wiring board 19 . Therefore, the heat of the light-emitting diodes 18 can be transmitted from a wide area of the wiring board 19 to the light source support 11 . This improves the heat conduction from the light-emitting diodes 18 to the light source support 11 , and increases the cooling performance of the light-emitting diodes 18 . [0071] Further, the lamp 1 of the first embodiment has the receptacle 12 to contain the lighting circuit 5 inside the outer shell 2 . This eliminates the necessity of arranging the lighting circuit 5 and outer shell 2 in the axial direction of the lamp 1 . Therefore, the length of the lamp 1 in the axial direction can be reduced, and the compact lamp 1 can be provided. [0072] The lighting circuit 5 contained in the receptacle 12 is electrically insulated from the outer shell 2 through the insulating member 6 . Therefore, the lighting circuit 5 can be incorporated in the outer shell 2 , while the outer shell 2 is made of metal to increase the heat radiation performance. [0073] The cup-shaped insulating member 6 for electrically insulating the outer shell 2 and the lighting circuit 5 is a synthetic resin molding with the heat conductivity lower than the outer shell 2 . Therefore the insulating member 6 can thermally shield the lighting circuit 5 from the outer shell 2 , and prevents conduction of the heat of the light-emitting diodes 18 to the lighting circuit 5 through the outer shell 2 . As a result, the lighting circuit 5 is protected from the heat of the light-emitting diodes 18 . This prevents a malfunction of the lighting circuit 5 , and makes the life of the lighting circuit 5 long. [0074] The receptacle 12 containing the lighting circuit 5 is surrounded by the peripheral wall 8 and the end wall 9 of the outer shell 2 , and the open end 12 a of the receptacle 12 is closed by the base 7 . In other words, the lighting circuit 5 is contained in a space portioned by the outer shell 2 and base 7 . The air outside the lamp 1 does not flow in this space. This prevents adhesion of dust in the air to the lighting circuit 5 causing a tracking phenomenon. [0075] FIG. 6 and FIG. 7 show a second embodiment of the invention. [0076] The second embodiment is different from the first embodiment in the outer shell 2 and translucent cover 4 . The other components of the lamp 1 and technical effects are the same as those of the first embodiment. Therefore, the same components as those of the first embodiment are given same reference numerals, and explanation of these components will be omitted. [0077] As shown in FIG. 6 and FIG. 7 , in the lamp 1 according to the second embodiment, the outside diameter of the peripheral wall 8 of the outer shell 2 is constant except the end portion adjacent to the open end 12 a of the receptacle 12 of the outer shell 2 . Therefore, the outer shell 2 is shaped like a straight cylinder. [0078] A globe as the translucent cover 4 has a reflection portion 41 a and a projection portion 41 b . The reflection portion 41 a has an opening 42 a opened to the light source support 11 , and an edge 42 b defining the opening 42 a . The edge 42 b is fit in the recession 14 of the outer shell 2 . The reflection portion 41 a is tapered to increase the diameter gradually from the edge 42 b . A light reflection film 43 is stacked on the inside surface of the reflection portion 41 a. [0079] The projection portion 41 b is formed integrally with the reflection portion 41 a so as to continue to the reflection portion 41 a . The projection portion 41 b is faced to the light reflection film 43 and light-emitting diodes 18 . [0080] With the translucent cover 4 formed as described above, a part of the light from the light-emitting diodes 18 can be reflected to the projection portion 41 b by using the light reflection film 43 . Therefore, most of the light from the light-emitting diodes 18 can be condensed by the projection portion 41 b , and projected to the outside of the lamp 1 . [0081] As shown in FIG. 7 , the outer shell 2 has a stopper 45 at the corner defined by the peripheral wall 8 and the end wall 9 . The stopper 45 is formed circular, projecting from the inside surface of the peripheral wall 8 and continuing to the inner circumference of the peripheral wall 8 . The stopper 45 is not limited to the circular form. For example, stoppers projecting from the inner circumference of the peripheral wall 8 may be arranged with intervals in the circumferential direction of the peripheral wall 8 . [0082] The inside diameter of the stopper 45 is smaller than the outside diameter of the closed wall 32 b of the insulating member 6 . Therefore, the stopper 45 is interposed between the end wall 9 and the closed wall 32 b of the insulating member 6 , even in the state that the insulating member 6 is fit in the receptacle 12 of the outer shell 2 . As a result, the light source support 11 on the end wall 9 is separated from the insulating member 6 , and a gap 46 is provided therebetween. [0083] According to the lamp 1 of the second embodiment, the existence of the gap 46 keeps the light source support 11 to receive the heat of the light-emitting diodes 18 non-contacting with the insulating member 6 . The gap 46 functions as a heat shielding space to prevent conduction of heat from the light source support 11 to the insulating member 6 , and the heat of the light-emitting diodes 18 are difficult to transmit directly from the light source support 11 to the insulating member 6 . [0084] Therefore, though the lighting circuit 5 is contained in the outer shell 2 which receives and radiates the heat of the light-emitting diodes 18 , the influence of heat to the lighting circuit 5 can be minimized. This prevents a malfunction of the lighting circuit 5 , and makes the life of the lighting circuit 5 long. [0085] FIG. 8 shows a third embodiment of the invention. [0086] The third embodiment is different from the first embodiment in the method of fixing the translucent cover 4 to the outer shell 2 . The other components of the lamp 1 and technical effects are the same as those of the first embodiment. Therefore, the same components as those of the first embodiment are given same reference numerals, and explanation of these components will be omitted. [0087] As shown in FIG. 8 , the edge 4 b of the translucent cover 4 is fixed to the recession 14 of the outer shell 2 through a silicon-based adhesive 51 . The adhesive 51 is filled in the recession 14 . The recession 14 is formed surrounding the light source support 11 , and caved in toward the base 7 from the supporting surface 11 a to fix the wiring board 19 . Therefore, the adhesive 51 is provided at the position displaced to the base 7 from the light-emitting diodes 18 on the wiring board 19 . [0088] According to the lamp 1 of the third embodiment, the adhesive 51 to fix the translucent cover 4 to the outer shell 2 is filled in the recession 14 caved in from the supporting surface 11 a of the light source support 11 . Therefore, the light from the light-emitting diodes 18 is difficult to apply directly to the adhesive 51 . This prevents deterioration of the adhesive 51 , even if the light from the light-emitting diodes 18 includes an ultraviolet ray. Therefore, the translucent cover 4 is securely fixed to the outer shell 2 for a long period. [0089] FIG. 9 to FIG. 11 shows a fourth embodiment of the invention. [0090] The fourth embodiment is different from the third embodiment in the shape of the light support 11 of the outer shell 2 . The other components of the lamp 1 and technical effects are the same as those of the third embodiment. Therefore, the same components as those of the third embodiment are given same reference numerals, and explanation of these components will be omitted. [0091] As shown in FIG. 9 to FIG. 11 , the end wall 9 of the outer shell 2 has a projection 61 projecting from the light source support 11 to the translucent cover 4 . The projection 61 is formed circular one size smaller than the light source support 11 . The projection 61 is formed integrally with the end wall 9 , and surrounded coaxially by the recession 14 to fix the translucent cover 4 . Therefore, one step 62 is formed between the projection 61 and light source support 11 . The step 62 is circular continuing to the circumferential direction of the projection 61 . [0092] A flat supporting surface 63 is formed at the end of the projection 61 . The supporting surface 63 is placed inside the translucent cover 4 more closely to the center than the end wall 9 of the outer shell 2 . Therefore, the supporting surface 63 is farther from the recession 14 by the distance equivalent to the height of the projection 61 . [0093] In the fourth embodiment, the wiring board 19 with the light-emitting diodes 18 mounted is fixed to the center of the supporting surface 63 through the screw 26 . The wiring board 19 is thermally connected to the supporting surface 63 . The screw hole 15 and through holes 16 a / 16 b are opened to the supporting surface 63 , penetrating through the projection 61 . [0094] According to the lamp 1 of the fourth embodiment, the projection 61 projecting to the translucent cover 4 is formed in the light support 11 of the outer shell 2 , and the wiring board 19 having the light-emitting diodes 18 is fixed to the end surface 63 of the projection 61 . Therefore, the light-emitting diodes 18 are displaced to be inside the translucent cover 4 more closely to the center than the end wall 9 of the outer shell 2 . This efficiently guides the light from the light-emitting diodes 18 to the inside of the translucent cover 4 , and permits radiation of the light from here to the outside of the translucent cover 4 . [0095] Further, the existence of the projection 61 increases the surface area and heat capacity of the light source support 11 . This increases the amount of heat radiation from the outer shell 2 , though the shape of the outer shell 2 is restricted by the appearance of the lamp 1 . As a result, the cooling performance of the light-emitting diodes 18 is increased, overheat of the light-emitting diodes 18 is prevented, and the life of the light-emitting diodes 18 can be made long. [0096] The light-emitting diodes 18 are farther from the adhesive 51 filled in the recession 14 by the distance equivalent to the height of the projection 61 . In other words, the light from the light-emitting diodes 18 to the recession 14 is blocked by the outer circumference of the projection 61 , and the light from the light-emitting diodes 18 is difficult to apply directly to the adhesive 51 . [0097] This prevents deterioration of the adhesive 51 , even if the light from the light-emitting diodes 18 includes an ultraviolet ray. Therefore, the translucent cover 4 is securely fixed to the outer shell 2 for a long period. [0098] FIG. 12 shows a fifth embodiment of the invention. [0099] The fifth embodiment is different from the second embodiment in the shape of the light source support 11 of the outer shell 2 . The other components of the lamp 1 and technical effects are the same as those of the second embodiment. Therefore, the same components as those of the second embodiment are given same reference numerals, and explanation of these components will be omitted. [0100] As shown in FIG. 12 , the end wall 9 of the outer shell 2 has a projection 71 projecting from the light source support 11 to the translucent cover 4 . The projection 71 is formed circular one size smaller than the light source support 11 . The projection 71 is formed integrally with the end wall 9 , and surrounded coaxially by the recession 14 to fix the translucent cover 4 . Therefore, one step 72 is formed between the projection 71 and light source support 11 . The step 72 is circular continuing to the circumferential direction of the projection 71 . [0101] A flat supporting surface 73 is formed at the end of the projection 71 . The supporting surface 73 is placed inside the reflection portion 41 a of the translucent cover 4 more closely to the center than the end wall 9 of the outer shell 2 . Therefore, the supporting surface 73 is farther from the recession 14 by the distance equivalent to the height of the projection 71 . [0102] In the fifth embodiment, the wiring board 19 with the light-emitting diodes 18 mounted is fixed to the center of the supporting surface 73 through the screw 26 . The wiring board 19 is thermally connected to the supporting surface 73 . The screw hole 15 and through holes 16 a / 16 b are opened to the supporting surface 73 , penetrating through the projection 71 . [0103] According to the lamp 1 of the fifth embodiment, the light-emitting diodes 18 are displaced to be inside the reflection portion 41 a of the translucent cover 4 more closely to the center than the end wall 9 of the outer shell 2 . This efficiently guides the light from the light-emitting diodes 18 to the inside of the translucent cover 4 . Therefore, the light from the light-emitting diodes 18 can be reflected to the projection portion 41 b through the light reflection film 43 , and radiated from the projection portion 41 b to the outside of the translucent cover 4 . [0104] Further, the existence of the projection 71 increases the surface area and heat capacity of the light source support 11 . This increases the amount of heat radiation from the outer shell 2 , though the shape of the outer shell 2 is restricted by the appearance of the lamp 1 . As a result, the cooling performance of the light-emitting diodes 18 is increased, overheat of the light-emitting diodes 18 is prevented, and the life of the light-emitting diodes 18 can be made long. FIG. 13 to FIG. 20 shows a sixth embodiment of the invention. [0105] The sixth embodiment is different from the first embodiment in the method of supporting the lighting circuit 5 to the receptacle 12 of the outer shell 2 . The other components of the lamp 1 and technical effects are the same as those of the first embodiment. Therefore, the same components as those of the first embodiment are given same reference numerals, and explanation of these components will be omitted. [0106] As shown in FIG. 13 and FIG. 14 , the wiring board 28 constituting the lighting circuit 5 is formed rectangular in the axial direction of the peripheral wall 8 of the outer shell 2 . The wiring board 28 has first to fourth edges 81 a , 81 b , 81 c and 81 d . The first and second edges 81 a and 81 b are extended along the axial direction of the peripheral wall 8 . The third and fourth edges 81 c and 81 d are extended along the radial direction of the peripheral wall 8 . The third edge 81 c butts against the closed wall 32 b of the insulating member 6 . The fourth edge 81 d faces to the base 7 . [0107] A first engaging part 82 a is formed at the corner of the wiring board 28 defined by the first edge 81 a and fourth edge 81 d. Similarly, a second engaging part 82 b is formed at the corner of the wiring board 28 defined by the second edge 81 b and fourth edge 81 d . The first and second engaging parts 82 a and 82 b are formed by notching two corners of the wiring board 28 rectangularly. The first and second engaging parts 82 a and 82 b are not limited to the notching. For example, projections projecting to the peripheral wall 8 may be provided at two corners of the wiring board 28 , and these projections may be used as the first and second engaging parts 82 a and 82 . Or, two corners themselves of the wiring board 28 may be used as the first and second engaging parts 82 a and 82 b. [0108] The wiring board 28 projects from the open end 12 a of the receptacle 12 to the inside of the connecting member 36 of the base 7 . In other words, the wiring board 28 extends over the outer shell 2 and the base 7 , and the fourth edge 81 d is placed inside the connecting member 36 . [0109] As shown in FIG. 13 , the circuit components 29 composing the lighting circuit 5 include a condenser 83 . The condenser 83 is weak to heat, and has a characteristic that the life is reduced when heated. The condenser 83 is mounted at the end portion of the first surface 28 a of the wiring board 28 adjacent to the fourth edge 81 d by means of soldering. [0110] Further, the lead terminal of each of the circuit components 29 projects from the second surface 28 b of the wiring board 28 , penetrating the wiring board 28 . Chip components 84 are mounted on the second surface 28 b. [0111] As shown in FIG. 14 , a pair of stoppers 85 a and 85 b is formed on the internal circumference of the connecting member 36 . The stoppers 85 a and 85 b project from the internal circumference of the connecting member 36 so as to correspond to the first and second engaging parts 82 a and 82 b of the wiring board 28 . The stoppers 85 a and 85 b contact the first and second engaging parts 82 a and 82 b of the wiring board 28 . Therefore, the wiring board 28 is held between the stoppers 85 a and 85 b of the base 7 and the end wall 9 of the outer shell 2 . [0112] As shown in FIG. 17 to FIG. 19 , a pair of guides 87 a and 87 b is formed integrally on the internal circumference of the peripheral wall 32 a of the insulating member 6 . The guides 87 a and 87 b are faced to each other in the radial direction of the peripheral wall 32 a , and projected from the internal circumference of the peripheral wall 32 a . Further, the guides 87 a and 87 b are extended along the axial direction of the peripheral wall 32 a. [0113] An engaging groove 88 is formed in the guides 87 a and 87 b . The first and second edges 81 a and 81 b are fit slidable in the engaging grooves 88 . The engaging grooves 88 are extended linearly along the axial direction of the peripheral wall 32 a. One ends of the engaging grooves 88 are closed by the closed wall 32 b of the insulating member 6 . The other ends of the engaging grooves 88 are opened to the other end of the peripheral wall 32 a. [0114] When installing the lighting circuit 5 in the receptacle 12 , insert the wiring board 28 into the inside of the peripheral wall 32 a of the insulating member 6 by setting the third edge 81 c of the wiring board 28 to the front. Insertion of the wiring board 28 is performed, while inserting the first and second edges 81 a and 81 b of the wiring board 28 into the engaging grooves 88 . When inserting the wiring board 28 into the inside of the peripheral wall 32 a , the third edge 81 c of the wiring board 28 butts against the closed wall 32 b of the insulating member 6 . This determines the insertion depth of the wiring board 28 into the insulating member 6 without taking special care. This improves the workability when installing the lighting circuit 5 in the receptacle 12 . [0115] After inserting the wiring board 28 into the inside of the peripheral wall 32 a of the insulating member 6 , connect the connecting member 36 of the base 7 to the open end 12 of the outer shell 2 . By this connection, the stoppers 85 a and 85 b of the connecting member 36 contact the first and second engaging parts 82 a and 82 b of the wiring board 28 . Therefore, the wiring board 28 is held between the end wall 11 of the outer shell 2 and the stoppers 85 a and 85 b , holding the lighting circuit 5 not to move in the axial direction of the peripheral wall 8 . As the first and second edges 81 a and 81 b of the wiring board 28 are fit in the engaging grooves 88 of the insulating member 6 , the lighting circuit 5 is held not to move in the circumferential direction of the peripheral wall 8 . Further, by intensifying the fitting of the first edge 81 a of the wiring board 28 in the engaging groove 88 , the lighting circuit 5 can be held not to move in the peripheral direction of the peripheral wall 8 only by fitting the first edge 81 a in the engaging groove 88 . [0116] Therefore, the lighting circuit 5 is held unmovable in the receptacle 12 of the outer shell 2 . [0117] As shown in FIG. 13 , the wiring board 28 of the lighting circuit 5 partitions the inside of the peripheral wall 32 a of the insulating member 6 into two areas 89 a and 89 b along the radial direction. The areas 89 a and 89 b are opened to a space 90 inside the base 7 , and connected with each other through the space 90 . [0118] The first and second surfaces 28 a and 28 b of the wiring board 28 are not directed to the light source support 11 which receives the heat of the light-emitting diodes 18 , and faced to the peripheral wall 32 a of the insulating member 6 . Therefore, the soldered parts of the lead terminals of the circuit components 29 to the wiring board 28 are separated away from the closed wall 32 b of the insulating member 6 contacting the light source support 11 , preventing the influence of heat to the soldered parts. [0119] Further, the condenser 83 adjacent to the fourth edge 81 d of the wiring board 28 is placed in the space 90 inside the base 7 , and separated away from the light source support 11 which receives the heat of the light-emitting diodes 18 . Therefore, the condenser 83 is difficult to be influenced by the heat of the light-emitting diodes 18 , and increased in the durability. [0120] In addition, as a part of the lighting circuit 5 is placed in the space 90 inside the base 7 , the lengths of the insulating member 6 and the outer shell 2 in the axial direction can be reduced. This is advantageous to make the lamp 1 compact. However, when the length of the outer shell 2 in the axial direction is reduced, the area of the heat radiating surface 10 is decreased. To solve this problem, increase the outside diameter of the outer shell 2 to compensate for the decrease of the area of the heat radiating surface 10 . [0121] As shown in FIG. 13 and FIG. 16 , the circuit components 29 mounted on the first surface 28 a of the wiring board 28 are higher than the chip components 84 mounted on the second surface 28 b . Therefore, the wiring board 28 of this embodiment is offset to the center line X 1 of the lamp 1 , so that the area 89 a between the first surface 28 a and the peripheral wall 32 a of the insulating member 6 becomes larger than the area 89 b between the second surface 28 b and the peripheral wall 32 a of the insulating member 6 . [0122] As a result, the high circuit components 29 can be separated as far as possible from the peripheral wall 8 of the outer shell 2 , and the circuit components 29 are difficult to be influenced by the heat of the light-emitting diodes 18 transmitted to the peripheral wall 8 . At the same time, a certain capacity can be ensured in the area 89 b between the second surface 28 b and the peripheral wall 8 of the outer shell 2 . Therefore, even if the lead terminals of the circuit components 29 are projected to the area 89 b from the second surface 28 b of the wiring bard 28 , the lead terminals are difficult to be influenced by the heat of the light-emitting diodes 18 transmitted to the peripheral wall 8 . This prevents overheat of the part where the lead terminals are soldered to the wiring board 28 . [0123] According to the lamp 1 of the sixth embodiment, the wiring board 28 of the lighting circuit 5 is contained in the receptacle 12 of the outer shell 2 in the state that the first and second surfaces 28 a and 28 b are faced to the internal circumference of the peripheral wall 32 a of the insulating member 6 . Therefore, the first or second surface 28 a or 28 b of the wiring board 28 is not faced to the closed wall 32 b of the insulating member 6 . [0124] Therefore, a substantially enclosed space is not formed between the wiring board 28 and closed wall 32 b , and the heat generated by the lighting circuit 5 or the heat of the light-emitting diodes 18 transmitted to the light source support 11 is difficult to stay at the end portion of the receptacle 12 adjacent to the light source support 11 . This prevents overheat of the light source support 11 , and is advantageous to increase the cooling performance of the light-emitting diodes 18 . [0125] Further, the wiring board 28 extends over the outer shell 2 and the base 7 , and the size of the wiring board 28 is not restricted by the inside diameter of the insulating member 6 . This increases the flexibility of determining the size of the wiring board 28 and laying out the circuit parts 29 on the wiring board 28 , and makes it easy to design the lighting circuit 5 . [0126] The sixth embodiment shows a structure to prevent a short circuit between the outer shell 2 and lead wires 30 a and 30 b. [0127] As shown in FIG. 14 and FIG. 15 , a pair of through holes 16 a and 16 b formed in the light source support 11 has a small diameter part 91 , a large diameter part 92 and a step 93 . The step 93 is positioned in the boundary between the small diameter part 91 and large diameter part 92 . [0128] An insulating cylinder 94 is fit in the through holes 16 a and 16 b . The insulating cylinder 94 is made of synthetic resin material having electric insulation such as polybutylene terephthalate. The insulating cylinder 94 extends over the small diameter part 91 and large diameter part 92 , covering the inside surfaces of the through holes 16 a and 16 b. [0129] The insulating cylinder 94 has an insertion hole 95 to pass the lead wires 30 a and 30 b . The insertion hole 95 extends over the through holes 33 a and 33 b of the insulating member 6 . As shown in FIG. 15 , an open edge adjacent to the through holes 33 a and 33 b of the insertion hole 95 is expanded in the diameter by chamfering. This prevents the lead wires 30 a and 30 b from being caught by the open edge of the insertion hole 95 when the lead wires 30 a and 30 b are guided from the through holes 33 a and 33 b to the insertion hole 95 . [0130] The insulating cylinder 94 is fit in the through holes 16 a and 16 b from the supporting surface 11 a of the light source support 11 . By fixing the wiring board 28 onto the supporting surface 11 a , the insulating cylinder 94 is held between the wiring board 28 and the step 93 of the through holes 16 a and 16 b , and the insulating cylinder 94 is held by the light source support 11 . Therefore, it is unnecessary to bond the insulating cylinder 94 to the light source support 11 . This makes it easy to assemble the lamp 1 . [0131] The lead wires 30 a and 30 b have a core 96 using a copper wire, for example, and an insulating layer 97 to cover the core 96 . The insulating layer 97 is removed at the ends of the lead wires 30 a and 30 b . Therefore, the core 96 is exposed to the outside of the insulating layer 97 at the ends of the lead wires 30 a and 30 b . The exposed core 96 is electrically connected to the wiring board 28 by means of soldering. [0132] If the insulating layer 97 is unevenly removed, the length of the core 96 exposed to the insulating layer 97 fluctuates. For example, as shown in FIG. 15 , when the lead wire 30 a is guided from the through hole 33 a to the through hole 16 a , the exposed core 96 may be positioned inside the through hole 16 a . The insulating cylinder 94 fit in the through hole 16 a is interposed between the exposed core 96 and the through hole 16 a , electrically insulating the core 96 and light source support 11 . [0133] Therefore, a short circuit between the exposed core 96 and light source support 11 can be prevented by the insulating cylinder 94 . [0134] The exposed core 96 is inserted from the insertion hole 95 into a pair of through holes 98 formed on the wiring board 19 , and guided onto the wiring board 19 through the through holes 98 . The end of the exposed core 96 is soldered to a land (not shown) formed on the wiring board 19 . [0135] The wiring board 28 of the lighting circuit 5 is offset to the center line X 1 of the lamp 1 as already described. Therefore, as shown in FIG. 16 , each through hole 98 can be placed between the adjacent areas 23 a and 23 b , and 23 c and 23 d of the thermal diffusion layer 23 . This does not decrease the area of the thermal diffusion layer 23 , though the through hole 98 penetrates the wiring board 19 . Therefore, the heat of the light-emitting diodes 18 can be efficiently transmitted to the light source support 11 through the thermal diffusion layer 23 , and prevents overheat of the light-emitting diodes 18 . [0136] FIG. 21 to FIG. 25 shows a seventh embodiment of the invention. [0137] A lamp 100 according to the seventh embodiment has an outer shell 101 , a light source 102 , a light source cover 103 , a cover holder 104 , a lighting circuit 105 , an insulating member 106 , a base 107 , and a heat shielding cover 108 . [0138] The outer shell 101 is made of metal material with excellent heat conductivity, such as aluminum. As shown in FIG. 24 , the outer shell 101 has a peripheral wall 110 and an end wall 111 . The peripheral wall 110 and the end wall 111 are formed integrally. The peripheral wall 110 is shaped like a straight cylinder. The outer circumference of the peripheral wall 110 is a heat radiating surface 112 . [0139] The end wall 111 closes one end of the peripheral wall 110 . The end wall 111 forms a circular plate light source support 113 . The light source support 113 has a flat supporting surface 114 on the opposite side of the peripheral wall 110 . [0140] A receptacle 116 is formed inside the outer shell 101 . The receptacle 116 is defined by a space surrounded by the peripheral wall 110 and end wall 111 , and positioned inside the heat radiating surface 112 . A stopper 117 is formed at a corner defined by the peripheral wall 110 and the end wall 111 . The stopper 117 is formed circular, projecting to the inside surface of the peripheral wall 110 and continuing in the circumferential direction of the peripheral wall 110 . The receptacle 116 has an open end 116 a facing to the end wall 111 . The open end 116 a is positioned at the other end of the peripheral wall 110 . An engaging groove 118 is formed in the internal circumference of the peripheral wall 110 . The engaging groove 118 is positioned at the open end 116 a of the receptacle 116 , and formed circular continuing in the circumferential direction of the peripheral wall 110 . [0141] A recession 119 is formed in the outer circumference of the end wall 111 . The recession 119 is circular surrounding the light source support 113 . A male screw 121 is formed in the internal circumference of the recession 119 . Instead of the male screw 121 , a female screw may be formed on the outer circumference of the recession 119 . [0142] As shown in FIG. 24 , a pair of through holes 122 a and 122 b and a pair of projections 123 a and 123 b are formed on the supporting surface 114 of the light source support 113 . The through holes 122 a and 122 b are arranged with an interval in the radial direction of the light source support 113 . The projections 123 a and 123 b are cylindrical, and project vertically from the supporting surface 114 . The projections 123 a and 123 b are arranged with an interval in the radial direction of the light source support 113 . The arrangement direction of the through holes 122 a and 122 b is orthogonal to the arrangement direction of the projections 123 a and 123 b. [0143] As shown in FIG. 21 and FIG. 24 , the light source 102 has a base 125 , a wiring board 126 , and a chip-shaped light-emitting element 127 . The base 125 is made of metal material with excellent heat conductivity, such as an aluminum alloy. The wiring board 126 is stacked on the base 125 . The light-emitting element 127 is a light-emitting diode, for example, and mounted at the center of the wiring board 126 . [0144] The light-emitting element 127 is covered by a transparent semispherical protection glass 128 . The wiring board 126 has lands 129 . The lands 129 are arranged with an interval in the circumferential direction of the wiring board 126 , just like surround the protection glass 128 . The wiring board 126 is covered by a not-shown insulating layer except the protection glass 128 and lands 129 . [0145] As shown in FIG. 24 , a pair of lead wire insertion parts 131 a and 131 b , a pair of first engaging parts 132 a and 132 b , and a pair of second engaging parts 133 a and 133 b are formed in the outer circumference of the base 125 and the wiring board 126 . The lead wire insertion parts 131 a and 131 b , first engaging parts 132 a and 132 b , and second engaging parts 133 a and 133 b are U-shaped notches. The lead wire insertion parts 131 a and 131 b , the first engaging parts 132 a and 132 b , and the second engaging parts 133 a and 133 b are not limited to the notches. They may be circular holes, for example. [0146] The lead wire insertion parts 131 a and 131 b , the first engaging parts 132 a and 132 b , and the second engaging parts 133 a and 133 b are alternately arranged with an interval in the circumferential direction of the base 125 and wiring board 126 . In other words, the lead wire insertion parts 131 a and 131 b , the first engaging parts 132 a and 132 b , and the second engaging parts 133 a and 133 b are positioned among the adjacent lands 129 . [0147] As shown in FIG. 21 and FIG. 22 , the base 125 of the light source 102 is stacked on the supporting surface 114 of the light source support 113 . A heat conduction sheet 135 having elasticity is interposed between the supporting surface 114 of the light source support 113 and the base 125 . The heat conduction sheet 135 is made of resin composed mainly of silicon, for example, and formed circular one size larger than the light source 102 . The heat conduction sheet 135 thermally connects the base 125 of the light source 102 and the light source support 113 . [0148] The heat conduction sheet 135 has escapes 136 a , 136 b , 136 c , 136 d , 136 e and 136 f on the periphery with an interval. The escapes 136 a , 136 b , 136 c , 136 d , 136 e and 136 f are U-shaped notches, for example. The escape 136 a and 136 b correspond to the lead wire insertion parts 131 a and 131 b . The escapes 136 c and 136 d correspond to the first engaging parts 132 a and 132 b . The escapes 136 e and 136 f correspond to the second engaging parts 133 a and 133 b. [0149] In the state that the heat conduction sheet 135 is held between the light source support 113 and base 125 , the projections 123 a and 123 b projecting from the supporting surface 114 are tightly fit in the first engaging parts 132 a and 132 b through the escapes 136 c and 136 d of the heat conduction sheet 135 . This fitting prevents movement of the light source 102 in the circumferential and radial directions of the light source support 113 . As a result, the light-emitting element 127 is positioned on the center line of the outer shell 101 , and the lead wire insertion parts 131 a and 131 b are aligned with the escapes 136 a and 136 b. [0150] As shown in FIG. 21 and FIG. 22 , the light source cover 103 has a lens 138 and a lens holder 139 . The lens 138 is used to control luminous intensity distribution of the lamp 101 , and is formed as one boy made of transparent material, such as glass and synthetic resin. [0151] The lens 138 has a light reflecting plane 140 , a light radiating plane 141 , a recession 142 , and a flange 143 . The light reflecting plane 140 is spherical, for example. The light radiating plane 141 is flat and faced to the light reflecting plane 140 . The recession 142 is caved in from the center of the light reflecting plane 140 to the light radiating plane 141 to permit fitting-in of the protection glass 128 . The recession 142 has a light entrance plane 144 surrounding the protection glass 128 . The flange 143 projects from the outer circumference of the lens 138 to the outside of the radial direction of the lens 138 . The flange 143 adjoins the light radiating plane 141 , and continues in the circumferential direction of the lens 138 . [0152] The lens holder 139 is a part separated from the lens 138 , and cylindrical surrounding the lens 138 . As shown in FIG. 25 , the lens holder 139 has a pair of holder elements 146 a and 146 b . The holder elements 146 a and 146 b are made of non-translucent synthetic resin material having electrical insulation, and formed semi-cylindrical. [0153] The holder elements 146 a and 146 b have a pair of projections 147 a and 147 b and a pair of recessions 148 a and 148 b . The projections 147 a and 147 b of one holder element 146 a fit in the recessions 148 a and 148 b of the other holder element 146 b . The projections 147 a and 147 b of the other holder element 146 b fit in the recessions 148 a and 148 b of one holder element 146 a . By this fitting, the holder elements 146 a and 146 b are butted against each other, and assembled as the cylindrical lens holder 139 . [0154] An engaging groove 149 is formed in the internal circumference of the lens holder 139 . The engaging groove 149 is positioned at one end along the axial direction of the lens holder 139 , and continued in the circumferential direction of the lens holder 139 . Projections 151 a and 151 b paired with a receiving part 150 are formed at the other end along the axial direction of the lens holder 139 . [0155] The receiving part 150 faces to the outer circumference of the wiring board 126 of the light source 102 , and has notches 152 . The notches 152 are arranged with an interval in the circumferential direction of the lens holder 139 , so as to correspond to the lands 129 of the light source 102 . The projections 151 a and 151 b correspond to the second engaging parts 133 a and 133 b of the light source 102 , and project from the other end of the lens holder 139 to the light source 102 . [0156] As shown in FIG. 25 , the holder elements 146 a and 146 b are butted against each other with the lens 138 interposed therebetween. By this arrangement, the flange 143 of the lens 138 is fit in the engaging groove 149 , and held between the holder elements 146 a and 146 b . As a result, the lens 138 is held inside the lens holder 139 , and the light radiating plane 141 of the lens 138 closes one end of the lens holder 139 . [0157] As shown in FIG. 21 and FIG. 22 , the light source 102 is held between the light source cover 103 and the light source support 113 of the outer shell 101 . Specifically, the receiving part 150 of the lens holder 139 contacts the wiring board 126 of the light source 102 , just like avoiding the lands 129 . Further, the projections 151 a and 151 b projecting from the lens holder 139 fit tightly in the second engaging parts 133 a and 133 b of the light source 102 . This fitting prevents movement of the light source cover 103 in the circumferential and radial directions of the light source 102 . Therefore, the protection glass 128 covering the light-emitting element 127 fits in the recession 142 of the lens 138 , and the lead wire insertion parts 131 a and 131 b or the first engaging parts 132 a and 132 b engage with the notches 152 of the receiving part 150 . [0158] Therefore, the position of the light source cover 103 is determined to the light source 102 , so that the optical axis X 2 of the lens 138 shown in FIG. 21 is aligned with the light-emitting element 127 . [0159] As shown in FIG. 21 , the cover holder 104 is formed as a cylinder or a square cylinder made of metal material with excellent heat conductivity, such as an aluminum alloy. The cover holder 104 has the same outside diameter of the outer shell 101 , and the inside diameter and length capable of covering the light source 102 and light source cover 103 continuously. [0160] A pressing part 155 is formed at one end of the cover holder 104 . The pressing part 155 is a flange projecting from the internal circumference to the inside of the radial direction of the cover holder 104 . A circular connecting part 156 is formed coaxially at the other end of the cover holder 104 . The connecting part 156 projects from the other end of the cover holder 104 to the recession 119 of the outer shell 101 . The connecting part 156 has a diameter smaller than the cover holder 104 . A step 157 is formed in the boundary between the connecting part 156 and the other end of the cover holder 104 . The step 157 has a flat surface continued to the circumferential direction of the cover holder 104 . [0161] A female screw 158 is formed in the internal circumference of the connecting part 156 . The female screw 158 can be fit over the male screw 121 of the recession 119 . If a female screw is formed in the outer circumference of the recession 119 instead of the male screw 121 , a male screw may be formed in the outer circumference of the connecting part 156 . [0162] The cover holder 104 is connected coaxially with the outer shell 101 by fitting the female screw 158 over the male screw 121 of the recession 119 . As the cover holder 104 is connected, the pressing part 155 of the cover holder 104 butts against one end of the lens holder 139 . The lens holder 139 is pressed to the light source support 113 of the outer shell 102 . Therefore, the light source cover 103 is held between the pressing part 155 of the cover holder 104 and the light source 102 . [0163] As shown in FIG. 21 and FIG. 22 , when the cover holder 104 is connected to the outer shell 102 , the outer circumference of the end wall 111 of the outer shell 102 butts against the step 157 of the cover holder 104 . This increases the contacting area of the outer shell 102 and the cover holder 104 , and increases a heat conduction path from the outer shell 102 to the cover holder 104 . [0164] The lighting circuit 105 is used to light the light-emitting element 127 , and contained in the receptacle 116 of the outer shell 102 . As the lighting circuit 105 is installed inside the outer shell 101 , it is unnecessary to arrange the outer shell 101 and lighting circuit 105 in the axial direction of the lamp 100 . Therefore, the length of the lamp 100 in the axial direction can be reduced, and the compact lamp 100 can be provided. [0165] As shown in FIG. 21 , the lighting circuit 105 has a wiring board 160 and circuit components 161 . The lighting circuit 105 is electrically connected to the light source 102 through two lead wires 162 and 162 b shown in FIG. 24 . The lead wires 162 a and 162 b are guided onto the wiring board 126 of the light source 102 through the lead wire insertion parts 131 a and 131 b of the light source 102 from the through holes 122 a and 122 b of the light source support 113 . The ends of the lead wires 162 a and 162 b are soldered to the two lands 129 . The insulating member 106 is an example of an insulating layer for electrically insulating the outer shell 101 and the lighting circuit 105 . The insulating member 106 is a molding using synthetic resin material such as polybutylene terephthalate. As shown in FIG. 21 , the insulating member 106 is cup-shaped having a cylindrical peripheral wall 163 a and a closed wall 163 b closing one end of the peripheral wall 163 a. [0166] The insulating member 106 is fit in the receptacle 116 through the open end 116 a . Therefore, the peripheral wall 163 a of the insulating member 116 butts contacts the internal circumference of the peripheral wall 110 of the outer shell 101 , and the closed wall 163 b of the insulating member 116 butts against the stopper 117 . The stopper 117 is interposed between the light source support 113 and the closed wall 163 b of the insulating member 116 . Therefore, the light source support 113 and closed wall 163 b are separated, and a gap 165 is provided between them. [0167] The existence of the gap 165 keeps the light source support 113 thermally connected to the light source 102 non-contacting with the insulating member 106 . The gap 165 functions as a heat shielding space to prevent conduction of heat from the light source support 113 to the insulating member 106 , and the heat of the light source 102 is difficult to transmit directly from the light source support 113 to the insulating member 106 . [0168] Therefore, though the lighting circuit 105 is contained in the outer shell 101 which receives the heat of the light source 102 , the lighting circuit 105 can be protected against the heat of the light source 102 . This prevents a malfunction of the lighting circuit 105 , and makes the life of the lighting circuit 105 long. [0169] The closed wall 163 b of the insulating member 106 has a not-shown pair of through holes. The through holes are formed to pass the lead wires 162 a and 162 b , and opened to the receptacle 116 and the gap 165 , penetrating the closed wall 163 b. [0170] The base 107 is used to supply an electric current to the lighting circuit 105 . The base 107 has a metal base shell 167 and a connecting member 168 fixed to the base shell 167 . The base shell 167 is removably connected to a lamp socket of a light fixture. The lamp 100 of the seventh embodiment is configured to be fit to a lamp socket with the base 107 faced up as shown in FIG. 21 . [0171] The connecting member 168 is a molding using synthetic resin material such as polybutylene terephthalate. The connecting member 168 has electrical insulation, and heat conductivity lower than the outer shell 101 . [0172] The connecting member 168 has a distal end 169 fit inside the open end 116 a of the receptacle 116 . An engaging projection 170 is formed in the outer circumference of the distal end 169 . The engaging projection 170 engages with the engaging groove 118 when the distal end 169 is fit inside the open end 116 a . By this engagement, the outer shell 101 and the base 107 are coaxially connected. The connecting member 168 is interposed between the base shell 167 and the outer shell 101 , and insulates them electrically and thermally. [0173] As shown in FIG. 21 , the connecting member 168 has an outer circumference 171 larger than the diameter of the distal end 169 . The outer circumference 171 projects coaxially to the outside of the radial direction of the outer shell 101 . A circular supporting wall 172 is formed in the outer circumference 171 of the connecting member 168 . The supporting wall 172 coaxially surrounds the distal end 169 of the connecting member 168 . A male screw 173 is formed on the outer peripheral surface of the supporting wall 172 . [0174] The heat shielding cover 108 is a molding using synthetic resin material, and formed like a hollow cylinder. The heat shielding cover 108 has heat conductivity lower than the outer shell 101 . As shown in FIG. 21 , the heat shielding cover 108 has the inside diameter and length capable of coaxially surrounding the outer shell 101 and cover holder 104 . [0175] A female screw 174 is formed in the internal circumference of one end of the heat shielding cover 108 . An engaging part 175 is formed at the other end of the heat shielding cover 108 . The engaging part 175 is a flange projecting from the internal circumference of the other end of the heat shielding cover 108 to the inside of the radial direction. The inside diameter of the engaging part 175 is smaller than the outside diameter of the cover holder 104 . [0176] The female screw 174 of the heat shielding cover 108 is fit over the male screw 173 of the connecting member 168 . By this fitting, the engaging part 175 of the heat shielding cover 108 is caught by one end of the cover holder 104 . Therefore, the cover 108 is connected to the connecting member 168 of the base 107 , surrounding the outer shell 101 and cover holder 104 coaxially. [0177] A heat radiating path 176 is formed between the heat shielding cover 108 and the outer shell 101 , and between the heat shielding cover 108 and the cover holder 140 . The heat radiating path 176 surrounds the outer shell 101 and cover holder 104 , and continues in the radial direction of the lamp 100 . [0178] One end of the heat radiating path 176 is closed by the outer circumference 171 of the connecting member 168 . Exhaust ports 177 are formed in the outer circumference 171 of the connecting member 168 . The exhaust ports 177 are arranged with an interval in the circumferential direction of the connecting member 168 , and connected to one end of the heat radiating path 176 . The other end of the heat radiating path 176 is closed by the engaging part 175 of the heat shielding cover 108 . Suction ports 178 are formed in the engaging part 175 of the heat shielding cover 108 . The suction ports 178 are arranged with an interval in the circumferential direction of the heat shielding cover 108 , and connected to the other end of the heat radiating path 176 . [0179] In the seventh embodiment, the suction ports 178 are formed in the engaging part 175 of the heat shielding cover 108 . Instead of the suction ports 178 , projections contacting one end of the cover holder 104 may be formed at the other end of the heat shielding cover 108 , and gaps between adjacent projections may be used as suction ports. Similarly, through holes opened to the heat radiating path 176 may be formed at the other end of the heat shielding cover 108 , and used as suction ports. [0180] Further, instead of forming the exhaust ports 177 in the base 107 , through holes opened to the heat radiating path 176 may be formed at one end of the heat shielding cover 108 , and used as exhaust ports. [0181] Next, explanation will be given on a procedure of assembling the lamp 100 . [0182] First, fit the insulating member 106 in the receptacle 116 of the outer shell 101 , and install the lighting circuit 105 in the receptacle 116 covered by the insulating member 106 . Next, guide the two lead wires 162 a and 162 b extending from the light circuit 105 , to the through holes 122 a and 122 b of the light source support 113 through the through holes of the closed wall 163 b. [0183] Then, place the heat conduction sheet 135 on the supporting surface 114 of the light source support 113 , and stack the base 125 of the light source 102 on the heat conduction sheet 135 . In this time, fit the projections 123 a and 123 b of the light source support 113 in the first engaging parts 132 a and 132 b of the light source 102 through the escapes 136 c and 136 d of the heat conduction sheet 135 . This fitting determines the relative positions of the light source 102 and the light source support 113 . Guide the lead wires 162 a and 162 b from the through holes 122 a and 122 b to the adjacent two lands 129 through the lead wire insertion parts 131 a and 131 b of the light source 102 , and solder the lead wires 162 a and 162 b to the lands 129 . [0184] Next, place the light source cover 103 on the wiring board 126 of the light source 102 . In this time, fit the projections 151 a and 151 b projected from the lens holder 139 , in the second engaging parts 133 a and 133 b of the light source 102 . This fitting determines the relative positions of the light source 102 and the light source support 103 . Therefore, the optical axis X 2 of the lens 138 coincides with the center of the light-emitting element 127 , and the receiving part 150 of the lens holder 139 butts against the outer circumference of the wiring board 126 . [0185] Next, insert the female screw 158 of the cover holder 104 onto the male screw 121 of the outer shell 102 , and connect the cover holder 104 coaxially with the outer shell 101 . As the cover holder 104 is connected, the pressing part 155 of the cover holder 104 butts against one end of the lens holder 139 , and presses the lens holder 139 toward the light source support 113 . As a result, the light source 102 is pressed to the supporting surface 114 of the light source support 113 through the lens holder 139 , and the heat conduction sheet 135 is tightly held between the supporting surface 114 and the base 125 of the light source 102 . [0186] The heat conduction sheet 135 is elastically deformed and tightly stuck to the supporting surface 114 and the base 125 . This eliminates a gap between the supporting surface 114 and the base 125 disturbing the conduction of heat, and provides good conduction of heat between the supporting surface 114 and the base 125 . In other words, comparing the case that the heat conduction sheet 135 is not used, the heat conduction performance from the light source 102 to the light source support 113 is improved. [0187] At the same time, the engagement of the male and female screws 121 and 158 is made tight by a repulsive force of the heat conduction sheet 135 to elastically return to the original form. Therefore, the cover holder 104 is difficult to become loose. [0188] For example, when the accuracy of the supporting surface 114 and base 125 is high, the heat conduction sheet 135 can be omitted. Instead of the heat conduction sheet 135 , conductive grease composed mainly of silicon may be used. [0189] When the light source 102 is pressed to the light source support 113 , a revolving force generated by insertion of the cover holder 104 acts on the light source cover 103 and light source 102 . As already explained, the relative position of the light source 102 to the light source support 113 is determined by the fitting of the projections 123 a and 123 b with the first engaging parts 132 a and 132 b . Similarly, the relative position of the light source cover 103 to the light source 102 is determined by the fitting of the projections 151 a and 151 b with the second engaging parts 133 a and 133 b. [0190] Therefore, the light source cover 103 and the light source 102 do not rotate following the cover holder 104 . An unreasonable force causing a break and a crack is not applied to the soldered part between the lands 129 of the light source 102 and the lead wires 162 a and 162 b . The lamp 100 can be assembled without giving a stress to the soldered part between the lead wires 162 a and 162 b and the lands 129 . [0191] Next, fit the base 107 to the outer shell 101 . This work is performed by fitting the distal end 169 of the base 107 in the open end 116 of the outer shell 101 , and engaging the engaging projection 170 with the engaging groove 118 . [0192] When fitting the base 107 to the outer shell 101 , the lighting circuit 105 may receive a force of pressing to the light source support 113 , from the connecting part 168 of the base 107 . This force is transmitted to the light source 102 through the lead wires 162 a and 162 h. [0193] The light source 102 is held between the light source cover 103 and the light source support 113 . Even if a force is applied to the light source 102 through the lead wires 162 a and 162 b , the light source 102 will not be separated from the supporting surface 114 of the light source support 113 . Therefore, the tight contact between the light source 102 and the light source support 113 is maintained, and the optical axis X 2 of the lens 138 will not be deviated from the center of the light-emitting element 127 . [0194] Finally, fit the heat shielding cover 108 to the outside of the outer shell 101 and the cover holder 104 , and insert the female screw 174 of the heat shielding cover 108 onto the male screw 173 of the connecting member 168 . By the insertion, the engaging part 175 of the heat shielding cover 108 is caught by one end of the cover holder 104 . As a result, the heat shielding cover 108 is connected to the base 107 , surrounding coaxially the outer shell 101 and the cover holder 104 , and the assembling of the lamp 100 is completed. [0195] In the state that the assembling of the lamp 100 is completed, the heat radiating path 176 positioned inside the heat shielding cover 108 is opened to the atmosphere through the suction ports 178 and exhaust ports 177 . [0196] In the lamp 100 of the seventh embodiment, when the lamp 100 is lit, the light-emitting element 127 is heated. The heat of the light-emitting element 127 is transmitted from the base 125 of the light source 102 to the light source support 113 through the heat conduction sheet 135 . The heat transmitted to the light source support 113 is transmitted to the heat radiating surface 112 from the end wall 110 through the peripheral wall 110 , and radiated from the heat radiating surface 112 to the heat radiating path 176 . [0197] The light source support 113 receiving the heat of the light-emitting element 127 is formed integrally with the peripheral wall 110 having the heat radiating surface 112 , and there is no joint disturbing the conduction of heat in a heat conduction path from the light source support 113 to the radiating surface 112 . Therefore, the thermal resistance of the heat conduction path can be controlled to small, and the heat of the light-emitting element 127 transmitted to the light source support 113 can be efficiently escaped to the heat radiating surface 112 . At the same time, as the whole surface of the heat radiating surface 112 is exposed to the heat radiating path 176 , the heat radiation from the heat radiating surface 112 is not disturbed. This improves the cooling performance of the light-emitting element 27 . [0198] Further, as the metal cover holder 104 is screwed into the outer shell 101 , the engagement of the female screw 174 and the male screw 173 thermally connects the outer shell 101 and the cover holder 104 . Therefore, the heat of the outer shell 101 is transmitted also to the cover holder 104 , and radiated from the outer peripheral surface of the cover holder 104 to the heat radiating path 176 . Therefore, the heat radiating area of the lamp 100 can be increased by using the cover holder 104 , and the cooling performance of the light-emitting element 127 is improved furthermore. [0199] When the heat of the light-emitting element 127 is radiated to the heat radiating path 176 , an ascending current is generated in the heat radiating path 176 . Therefore, the air outside the lamp 100 is taken in the heat radiating path 176 through the suction ports 178 positioned at the lower end of the lamp 100 . The air taken in the heat radiating path 176 flows from the lower to upper side in the heat radiating path 176 , and is radiated to the atmosphere through the exhaust ports 177 . [0200] The outer circumference of the cover holder 104 and the heat radiating surface 112 of the outer shell 101 are exposed to the heat radiating path 176 . The heat of the light-emitting element 127 transmitted to the cover holder 104 and the outer shell 101 is taken away by the heat exchange with the air flowing in the heat radiating path 176 . Therefore, the cover holder 104 and the outer shell 101 can be cooled by the air, and overheat of the light-emitting element 127 can be prevented. This prevents decrease of the light-emitting efficiency of the light emitting element 127 , and makes the life of the light-emitting element 127 long. [0201] The heat shielding cover 108 to cover the cover holder 104 and the outer shell 101 is made of synthetic resin material with a low heat conductivity. Therefore, the heat of the cover holder 104 and the outer shell 101 is difficult to transmit to the heat shielding cover 108 , and the temperature of the heat shielding cover 108 is decreased to lower than the outer shell 101 . [0202] According to the seventh embodiment, the connecting member 168 to fit with the heat shielding cover 108 is made of synthetic resin, and the connecting member 168 thermally insulates the outer shell 101 and the heat shielding cover 108 . Further, the engaging part 175 of the heat shielding cover 108 to contact the cover holder 104 has the suction ports 178 . Even if the heat of the cover holder 104 is transmitted to the engaging part 175 of the heat insulating cover 108 , the engaging part 175 is cooled by the air flowing into the heat radiating path 176 through the suction ports 178 . Therefore, the heat shielding cover 108 is difficult to be influenced by the heat of the cover holder 104 , and the temperature increase of the heat shielding cover 108 can be prevented. [0203] According to the lamp 100 of the seventh embodiment, even if the operator holds the heat insulating cover 108 by hand when replacing the lamp 100 during lighting or immediately after turning off the lamp, the operator does not feel hot. Therefore, the operator does not drop the lamp 100 when touching the lamp and surprised by the heat, and can safely replace the lamp 100 . [0204] In the seventh embodiment, fine holes may be formed in the heat insulating cover 108 . Instead of holes, slits may be formed along the axial or circumferential direction of the heat shielding cover 108 . [0212] FIG. 26 and FIG. 27 show an eighth embodiment of the invention. [0205] The eighth embodiment is different from the seventh embodiment in the configuration for radiating the heat of the outer shell 101 and the cover holder 104 . The other components of the lamp 100 and technical effects are the same as those of the seventh embodiment. Therefore, the same components as those of the seventh embodiment are given same reference numerals, and explanation of these components will be omitted. [0206] The lamp 100 according to the eighth embodiment has the following configuration instead of the heat shielding cover 108 in the seventh embodiment. As shown in FIG. 26 and FIG. 27 , the outer shell 101 has first heat radiating fins 200 . The first heat radiating fins 200 project radially from the heat radiating surface 112 of the outer shell 101 . The first heat radiating fins 200 are extended in the axial direction of the outer shell 101 , and arranged with an interval in the circumferential direction of the outer shell 101 . [0207] The cover holder 104 has second heat radiating fins 201 . The second heat radiating fins 201 project radially from the outer circumference of the cover holder 104 . The second heat radiating fins 201 are extend in the axial direction of the cover holder 104 , and arranged with an interval in the circumferential direction of the cover holder 104 . [0208] The first and second heat radiating fins 200 and 201 continue each other along the axial direction of the lamp 100 . Therefore, the first and second heat radiating fans 200 and 201 are thermally connected, and directly exposed to the outside of the lamp 100 . [0209] The distal edges of the first heat radiating fins 200 are covered by first edge covers 202 . Similarly, the distal edges of the second heat radiating fins 201 are covered by second edge covers 203 . The first and second edge covers 202 and 203 are mode of synthetic resin. The first and second edge covers 202 and 203 have heat conductivity lower than the outer shell 101 and the cover holder 104 . [0210] According to the lamp 100 of the eighth embodiment, the existence of the first heat radiating fins 200 increase the heat radiating area of the heat radiating surface 112 of the outer shell 101 . Likewise, the existence of the second heat radiating fins 201 increases the heat radiating area of the peripheral surface of the cover holder 104 . Therefore, the heat of the light-emitting element 127 transmitted to the outer shell 101 and the cover holder 104 can be efficiently radiated to the outside of the lamp 100 . This can prevent the decrease of the light-emitting efficiency of the light-emitting element 127 , and make the life of the light-emitting element 127 long. [0211] Further, the first and second edge covers 202 and 203 covering the distal edges of the first and second heat radiating fins 200 and 201 have heat conductivity lower than the outer shell 101 and the cover holder 104 . Therefore, the heat of the outer shell 101 and the cover holder 104 is difficult to transmit to the first and second edge covers 202 and 203 , and the temperatures of the first and second edge covers 202 and 203 can be decreased to lower than the outer shell 101 and the cover holder 104 . [0212] As a result, even if the operator holds the first and second heat radiating fins 200 and 201 by hand when replacing the lamp 100 during lighting or immediately after turning off the lamp, the operator does not feel hot. Therefore, the operator does not drop the lamp 100 when touching the lamp and surprised by the heat, and can safely replace the lamp 100 . [0213] FIG. 28 and FIG. 29 show a ninth embodiment of the invention. [0214] The ninth embodiment is developed from the eight embodiment. The configuration of the lamp 100 is the same as the eight embodiment. Therefore, the same components as those of the eighth embodiment are given same reference numerals, and explanation of these components will be omitted. [0215] The lamp 100 of the ninth embodiment has an outside cylinder 220 surrounding the first and second heat radiating fins 200 and 201 . The outside cylinder 220 is formed like a hollow cylinder with the diameter larger than the outer shell 101 and the cover holder 104 . The outside cylinder 220 has the length extending over the peripheral wall 110 of the outer shell 101 and the cover holder 104 . The inner peripheral surface of the outside cylinder 220 contacts the first and second edge covers 202 and 203 . Therefore, the outside cylinder 220 extends over the adjacent first and second heat radiating fins 200 and 201 . [0216] In other words, the outside cylinder 220 faces to the heat radiating surface 112 through the first heat radiating fins 200 , and faces to the peripheral surface of the cover holder 104 through the second heat radiating fins 201 . Therefore, a heat radiating path 221 is formed between the heat radiating surface 112 of the outer shell 101 and the outside cylinder 220 , and between the peripheral surface of the cover holder 104 and the outside cylinder 220 . The heat radiating path 221 continues in the axial direction of the lamp 100 . The first and second heat radiating fins 200 and 201 are exposed to the heat radiating path 221 . The heat radiating path 221 has one end 221 a and the other end 221 b . The one end 221 a of the heat radiating path 221 is opened to the atmosphere from the lower end of the second heat radiating fins 201 , when the lamp 100 is lit with the base 107 faced up. Likewise, the other end 221 b of the heat radiating path 221 is opened to the atmosphere from the upper end of the first heat radiating fins 200 , when the lamp 100 is lit with the base 107 faced up. [0217] The outside cylinder 220 is made of material with heat conductivity lower than the outer shell 101 and the cover holder 104 . For example, when the outside cylinder 220 is made of heat shrinking synthetic resin, it is desirable to heat the outside cylinder 220 to shrink by the heat, after fitting the outside cylinder 222 to the outside of the outer shell 101 and the cover holder 104 . The inner circumference of the outside cylinder 220 is pressed to the first and second edge covers 202 and 203 , and the outside cylinder 220 is connected integrally with the outer shell 101 and the cover holder 104 . This facilitates fitting of the outside cylinder 220 . [0218] In the lamp 100 of the ninth embodiment, when the heat of the light-emitting element 127 is radiated to the heat radiating path 221 , an ascending current is generated in the heat radiating path 221 . Therefore, the air outside the lamp 100 is taken in the heat radiating path 221 through one end 221 a of the heat radiating path 221 . The air taken in the heat radiating path 221 flows from the lower to upper side in the heat radiating path 221 , and is radiated to the atmosphere through the other end 221 b of the heat radiating path 221 . [0219] The heat of the light-emitting element 127 transmitted to the cover holder 104 and the outer shell 101 is taken away by the heat exchange with the air flowing in the heat radiating path 221 . Therefore, the outer shell 101 having the first heat radiating fins 200 and the cover holder 104 having the second heat radiating fins 201 can be cooled by the air, and overheat of the light-emitting element 127 can be prevented. This prevents decrease of the light-emitting efficiency of the light emitting element 127 , and makes the life of the light-emitting element 127 long. [0220] The outside cylinder 220 is made of synthetic resin material with the heat conductivity lower than the outer shell 101 and the cover holder 104 . Therefore, the heat of the cover holder 104 and the outer shell 101 is difficult to transmit to the outside cylinder 220 , and the temperature of the outside cylinder 220 is decreased to lower than the outer shell 101 and the cover holder 104 . [0221] As a result, even if the operator holds the outside cylinder 220 by hand when replacing the lamp 100 during lighting or immediately after turning off the lamp, the operator does not feel hot. Therefore, the operator does not drop the lamp 100 when touching the lamp and surprised by the heat, and can safely replace the lamp 100 . [0222] Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

According to one or more arrangements, a lighting device such as a lamp may include a cover a device body. The device body may have a projection having a support surface at one end and an attachment portion to which the cover is configured to attach. In one or more examples, while the cover is configured to attach to the attachment portion, the cover may be configured to cover the supporting surface of the projection. The cover portion may include a translucent cover portion in some configurations. Additionally or alternatively, the supporting surface of the projection portion may be disposed closer to a center of the cover portion than the attachment portion. In one example, the projection portion may be disposed closer to the cover portion center by a distance equal to a height of the projection portion.

“This application claims priority from PCT/IL199/00563 filed Oct. 25, 1999, which claims priority from U.S. Provisional Application 60/105,568 filed Oct. 25, 1998.” FIELD AND BACKGROUND OF THE INVENTION The present invention relates to ultrasonic tissue imaging techniques and, in particular, it concerns a method and apparatus for the ultrasonic evaluation of bone tissue. It is known that ultrasonography is often used for diagnostic tissue imaging in human beings. As soft or fluid filled tissues possess favorable acoustic properties, ultrasonography is able to provide excellent imagine of these tissues. The ultrasonic evaluation of bone tissue, however (for example, for estimating the degree of osteoporosis, and thus bone fracture risk) is problematic, due to the difficulty in achieving adequate ultrasound penetration in complex solid biological structures Such as bone. To date, therefore, the reliable ultrasonic imaging of bone structure and density and has not been possible. Ultrasonic evaluation of bone tissue, as with any biological tissue, is achieved by transmitting an ultrasonic pulse or pulses into the bone tissue, and then analyzing the acoustic qualities of the received reflected ultrasonic signals. Properties of bone tissue can then be determined by analyzing the amplitude and/or travel time of the received signals. The amplitude of the received pulses, which indicates the degree of attenuation of the transmitted ultrasound signals, correlates with bone mineral density. The travel time of the signal transmitted through the bone tissue is used for calculating the velocity of the ultrasound signal within the bone tissue, the so-called “speed of sound” (SOS), which also correlates with the degree of osteoporosis and/or risk of bone fracture. Several techniques for the ultrasonic evaluation of bone tissue are known in the art. FIG. 1 depicts a conventional ultrasonic apparatus for evaluation of bone tissue, generally designated 10 . Ultrasonic apparatus 10 for the evaluation of bone tissue includes an ultrasonic probe 12 for transmitting ultrasonic pulses towards a bone 14 via soft tissue 16 , and for receiving signals reflected from or transmitted through, bone 14 . Ultrasonic probe 12 is typically a hand-held implement for manipulation by an operator. The operator grips ultrasonic probe 12 and applies it to soft tissue 16 . As the surface of bone 14 is inaccessible for direct coupling with ultrasonic probe 12 , the operator is required to adjust the position and apposition of ultrasonic probe 12 on soft tissue 16 , in order to optimize the transmission into, and reception from, bone 14 of ultrasound signals. When ultrasonic probe 12 is optimally oriented, the amplitude of the received signals is maximal while the time of flight is minimal. Ultrasonic apparatus 10 for evaluation of bone tissue further includes a digital computing device 18 for analyzing the received ultrasound signal and generating an image of bone 14 from the measured amplitude and/or time delay of the received signal. Ultrasonic apparatus 10 for evaluation of bone tissue also includes a display 20 for displaying the image generated by computing device 18 . Turning now to FIG. 2, a part of ultrasonic apparatus 10 is depicted, including ultrasonic probe 12 . As the internal structure of bone 14 is inhomogeneous, the ultrasound signal received by probe 12 typically has a low signal to noise ratio. As such, the through transmission technique is typically employed, in which one transducer (that is, a scanning crystal) transmits signals while a second transducer receives the signals after they have traveled through the substance under investigation. Ultrasonic probe 12 typically includes two resonant scanning crystals 22 and 24 , which work at a fixed frequency, and which are connected to digital computing device 18 . Scanning crystal 22 is operative to transmit ultrasonic pulses toward bone 14 via soft tissue 16 , while scanning crystal 24 is operative to receive ultrasonic signals which have passed through, or been reflected by, bone 14 and soft tissue 16 . Each of scanning crystals 22 and 24 have inclined delay lines 26 and 28 respectively. In other words, the part of the transducer in front of the scanning crystal, through which the longitudinal waves generated by the scanning crystal pass prior to entering the tissue to which the transducer has been applied, is inclined at an acute angle to the surface of that tissue. The velocity of ultrasound within delay lines 26 and 28 is approximately equal to the velocity of ultrasound in soft tissue 16 . Delay line 26 typically directs scanning crystal 22 at an angle α with regard to the surface of soft tissue 16 , so as to cause propagation of longitudinal leaky waves along the surface of bone 14 . Delay line 28 directs scanning crystal 24 by the same angle α with regard to the surface of soft tissue 16 , so as to facilitate optimal reception of the ultrasound signal passed along bone 14 . The net travel time for ultrasound signals that have passed through bone 14 is described by the formula: T 14 =T Σ −T 26 −T 28 −T 16 , where T 14 is the net travel time for a signal passed through bone 14 ; T Σ is the time delay between transmission of an ultrasonic pulse by scanning crystal 22 and reception of the pulse by scanning crystal 24 ; T 26 and T 28 are the propagation times for ultrasonic pulses in delay lines 26 and 28 respectively; and T 16 is the propagation time for ultrasonic pulses in soft tissue 16 . Two auxiliary crystals 30 and 32 are located in ultrasonic probe 12 , and are connected to digital computing device 18 . Auxiliary crystals 30 and 32 are typically used to determine the propagation time for ultrasonic pulses in soft tissue 16 . This is achieved by crystal 30 transmitting an ultrasonic pulse into soft tissue 16 while crystal 32 receives the reflected echo pulse from the surface of bone 14 . The measured delay between transmission and reception of this echo pulse determines the value of T 16 . The velocity of ultrasound (SOS) in bone 14 is described by the formula: SOS = BTD T 14 Per the following reason: It is well known that V  [ m / sec ] = D    [ m ] T    [ sec ]  SOS is defined as velocity; BTD is defined as distance and T is defined as time. where BTD is the bone travel distance, which is determined by the distance between scanning crystals 22 and 24 and the value of angle α. Ultrasonic travel time and/or amplitude measurements for an ultrasonic pulse which has passed through bone 14 are heavily influenced by the proficiency with which the operator applies ultrasonic probe 12 to soft tissue 16 . Several techniques for maximizing operator proficiency have been described in the art. A typical technique is illustrated in FIG. 3, in which a part of ultrasonic apparatus 10 is depicted, including ultrasonic probe 12 . As shown in the figure, additional auxiliary crystals 34 and 36 are located within probe 12 , and are connected to digital computing device 18 . Crystal 34 is operative to transmit ultrasonic pulses into soft tissue 16 , while crystal 36 is operative to receive the reflected echo pulse from the surface of bone 14 . The measured delay between transmission and reception of said echo pulse is T 16a . When I 16 =T 16a , probe 12 is oriented in such a way that the BTD will be the shortest possible for that probe. A smaller value for BTD minimizes the impact of inevitable inaccuracies in the calculation of SOS. Thus, when digital computing device 18 determines that T 16 =T 16a , probe 12 is deemed to be oriented appropriately with regard to soft tissue 16 , and the received echo signals are analyzed so as to image bone 14 . When the condition T 16 T 16a is not met, received ultrasound signals are ignored by digital computing device 18 . In an alternative method for minimizing operator unreliability, the operator applies ultrasonic probe 12 to a reference block made from material with known acoustical properties prior to applying probe 12 to soft tissue 16 and bone 14 . The operator can then compare the actual images obtained from bone 14 with the “optimal” images obtained from the reference block, and continues to adjust the orientation of probe 12 until such time as the current image approximates the “optimal images.” The above-described methods for ultrasonic imaging of bone, however suffer from several deficiencies: 1. It is common experience that the repeatability and precision of travel time and amplitude measurements for signals passed through bone 14 is low, even when optimal orientation of ultrasonic probe 12 with respect to bone 14 is achieved. Furthermore, as the exact propagation times T 26 and T 28 of ultrasonic signals in delay lines 26 and 28 are unknown, calculated values for ultrasound velocity (SOS) are unreliable. 2. The methods used for optimizing the orientation of probe 12 with regard to bone 14 do not relate to the signal actually received from bone 14 , but rather, infer an optimal bone-probe orientation from signals received from other materials (either soft tissue 16 or a reference block). 3. As the dense cortex of bone 14 distorts transmitted signals, current fixed-frequency ultrasonic bone imaging techniques allow only for an integral evaluation of the surface of bone 14 , but not for the imaging of the internal structure of bone 14 (for example, so as to reveal local inhomogeneities and fractures). Furthermore, as current techniques utilize ultrasonic pulses of a single, fixed, frequency- and measure only amplitude or travel time changes in the received signal-additional ultrasonic phenomena, such as possible changes in the frequency spectrum of the transmitted pulse induced by the internal structure of bone, are not evaluated. Such phenomena, however, may reveal information about the internal structure of bone, which cannot be inferred from single parameter measurements (such as amplitude or travel time). There is therefore a need for, and it would be highly advantageous to have a method and device for achieving ultrasonic imaging of bone tissue which would allots for the precise and easily repeatable measurement of ultrasonic travel time and signal amplitude, the imaging of the internal structure of bone tissue, and the optimization of probe orientation by directly utilizing the imaging signals received from the bone. SUMMARY OF THE INVENTION The invention is a method and device for the ultrasonic imaging of bone tissue. According to the teachings of the present invention there is provided, a method for ultrasonic imaging of bone tissue, including the steps of transmitting a repeating ultrasonic signal into the bone tissue, the ultrasonic signal having a frequency and containing a number of full waves; receiving the transmitted signal; determining the number of full waves in the received signal; defining, as a first definition, whether or not the determined number of full waves in the received signal is equal to the number of full waves in the transmitted repeating ultrasonic signal; and modifying the frequency of the transmitted repeating ultrasonic signal in accordance with the first definition. There is further provided a method for optimizing the orientation of an ultrasound probe on bone tissue, including the steps of transmitting an ultrasound signal into the bone tissue from a transmitter in the ultrasound probe; receiving the transmitted ultrasound signal by a first receiver in the ultrasound probe; receiving the transmitted ultrasound signal by a second receiver in the ultrasound probe, the second receiver being displaced from the first receiver, in relationship to the transmitter; and correlating the ultrasound signal received by the first receiver with the ultrasound signal received by the second receiver. There is further provided a bone tissue ultrasonic imaging system, including a first wide band scanning crystal for transmitting an ultrasonic signal into the bone tissue; a frequency selection mechanism for selecting a frequency for the transmitted ultrasonic signal; a full wave quantity selection mechanism for selecting a quantity of full waves for the transmitted ultrasonic signal; a second wide band scanning crystal for receiving the transmitted ultrasonic signal; a full wave quantity counting mechanism for counting a quantity of full waves in the received ultrasonic signal, and inputting to the frequency selection mechanism a desired output frequency; a waveform analyzing mechanism for analyzing waveforms in the received ultrasonic signal, inputting to the frequency selection mechanism a desired output frequency, and inputting to the full wave quantity selection mechanism a desired quantity of full waves for the transmitted ultrasonic signal. There is further provided a system for optimizing the orientation of a bone ultrasonic imaging probe, including a first wide band scanning crystal for transmitting an ultrasonic signal into the bone tissue; a second wide band scanning crystal for receiving the transmitted ultrasonic signal; a third wide band scanning crystal for receiving the transmitted ultrasonic signal, the third wide band scanning crystal being displaced from the second wide band scanning crystal, in relationship to the first wide band scanning crystal; and a mechanism for correlating the received ultrasonic signal from the second wide band scanning crystal with the received ultrasonic signal from the third wide band scanning crystal. BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: FIG. 1 is a schematic illustration of a conventional ultrasonic apparatus for imaging bone tissue; FIG. 2 is a schematic illustration, in cross section, of a conventional ultrasonic apparatus for imaging bone tissue; FIG. 3 is a schematic illustration, in cross section, of a conventional ultrasonic apparatus for imaging bone tissue, including an ultrasonic probe with two scanning ultrasonic crystals and two auxiliary ultrasonic crystals; FIG. 4 is a diagram of the waveform of an experimentally transmitted ultrasound pulse; FIG. 5 is a first example of scope screenshots of experimental signals passed through bone tissue; FIG. 6 is a second example of scope screenshots of experimental signals passed through bone tissue; FIG. 7 is a third example of scope screenshots of experimental signals passed through bone tissue; FIG. 8 is a fourth example of scope screenshots of experimental signals passed through bone tissue; FIG. 9 is a graph depicting ultrasound velocity as a function of depth of penetration into bone tissue; FIG. 10 is a schematic illustration of a first preferred embodiment of an ultrasonic apparatus for imaging bone tissue; FIG. 11 is a diagram of ultrasound frequencies received and transmitted by a resonant crystal; and FIG. 12 is a schematic illustration of a second preferred embodiment of an ultrasonic apparatus for imaging bone tissue. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a method and device for achieving ultrasonic imaging by bone tissue. By “imaging” is meant the acquisition or derivation of any ultrasonic. variable or function that correlates with the internal structure of a bone tissue under ultrasonic interrogation. Once the variables or functions have been acquired they may then be used to create a display depicting the anatomy and structure of the tissue. The current invention relates primarily to novel techniques for acquiring and deriving reliable ultrasonic imaging data from bone tissue. A variety of existing techniques for displaying such imaging data may then be used to generate a graphic depiction of the bone under investigation. The crystal principles and operation of a method and device for achieving ultrasonic imaging of bone tissue, according to the present invention, may be better understood with reference to the drawings and the accompanying description. Tuning now to FIGS. 4 and 5, the results of experimental transmission of ultrasonic signals into bone tissue by a wide band ultrasonic crystal are shown. The waveform of the transmitted ultrasonic signal is depicted in FIG. 4 . In FIG. 5 the oscilloscope screenshots show the ultrasonic signal received by a second wide band ultrasonic crystal after transmission, into bone tissue, of a single ultrasonic pulse comprising four waves. In all the examples demonstrated in FIG. 5, the bone travel distance for the ultrasonic pulse was 20 mm and the attenuation of the ultrasonic wave on the surface of the bone tissue as 10 dB/cm at 0.5 MHz. In signals 501 through 508 , the frequency of the transmitted pulse was progressively decreased, from 2 MHz to 0.55 MHz. It is noteworthy that in signals 501 through 504 , in which the transmission frequency was high, the received signal comprised only a single wave, whereas in signals 505 through 508 , as the transmission frequency decreased towards 0.55 MHz, additional wave components became discernable. At a transmission frequency of 0.55 MHz, four wave components were consistently discernable, indicating that the received signal was of a similar wave composition to that of the transmitted pulse. These results demonstrate that when ultrasound pulses are transmitted into bone tissue at excessively high frequencies, the received signal is highly deformed with respect to the transmitted pulse. When the transmission frequency is appropriate (in the demonstrated example: 0.55 MHz), however, the waveform of the transmitted pulse is preserved. As can be seen in FIG. 5, the four waves constituting the received pulse in signal 508 were each of different amplitude. In signals 509 through 511 the transmission frequency was kept constant, while the number of waves in the transmitted pulse was gradually increased. Signal 511 demonstrates that a steady state was achieved (wherein at least 2 consecutively received waves were of identical amplitude) when the transmitted pulse comprised seven waves. The transmitted signal comprised an integer number of half waves of a sinusoid. FIG. 6 shows the results of a similar experiment to that described in FIG. 5, except that the bone travel distance was shorter (10 mm rather than 20 mm). The results of this experiment were consistent with those of the experiment shown in FIG. 5 . In this experiment, the transmission frequency at which the waveform of the transmitted pulse was preserved was found to be 0.65 MHz. As in FIG. 5, increasing the number of waves in the transmitted pulse to seven resulted in a steady state for amplitude of the received waves being achieved. FIG. 7 shows the results of a similar experiment to that described in FIG. 6, except that the attenuation of the transmitted pulse was greater than that of the transmitted pulse in FIG. 6 (16 dB/cm as opposed to 10 dB/cm, at 0.5 MHz). The results of this experiment were consistent with those of the experiments shown in FIGS. 5 and 6. In this experiment, the transmission frequency at which the waveform of the transmitted pulse was preserved was found to be 0.6 MHz. As in FIGS. 5 and 6, increasing the number of waves in the transmitted pulse to seven resulted in a steady state for amplitude of the received waves being achieved. These experiments show that when transmitting ultrasound signals into bone tissue, the quantity of full waves in the received signal approaches, and eventually becomes equal to, the quantity of full waves in the transmitted pulse, as the frequency of the transmitted pulse is progressively reduced. It should be emphasized that, as will be well known to one familiar with acoustic theory, reception of an ultrasonic pulse having an equal number of full waves to that of the transmitted pulse indicates that the transmitted pulse successfully penetrated at least pail of the bone tissue under interrogation. This phenomenon is of crucial relevance to ultrasonic bone imaging techniques because the accurate calculation of time of flight and amplitude attenuation of received ultrasound waves is feasible only when the received signal is comparable to the transmitted signal in terms of its waveform, that is, when penetration of the transmitted signal has occurred. Distortion of the transmitted wave during propagation through tissue (due to incomplete penetration) prohibits meaningful comparison of the amplitudes and times of flight of the transmitted and received waves. As described above, standard ultrasonic imaging techniques utilize fixed, single frequency, transducers, the frequency of which bear no relevance to local bone conditions and are usually inappropriate for that bone. Furthermore, standard ultrasonic imaging techniques provide no mechanism for indicating to the user whether or not penetration of the bone tissue by the transmitted wave has actually been achieved. The phenomenon of frequency-induced wave distortion in bone tissue thus renders standard ultrasonic imaging techniques inadequate for use on bone tissue, usually precluding imaging of the internal structure of bone as well as precluding precise measurement of amplitude and travel time. The critical frequency at which the equalization of transmitted and received waveforms occurs is thus the upper limit for the frequency at which ultrasonic interrogation of bone tissue can be meaningfully performed. The experiments reported in FIG. 5, FIG. 6 and FIG. 7 show that the value of this upper frequency limit depends on the properties of the particular bone tissue under interrogation (for example, ultrasonic attenuation in the bone) and on the bone travel distance (i.e. the distance between the scanning crystals in the ultrasonic probe). The experimental results reported above also demonstrate that for meaningful ultrasonic imaging of bone tissue to be performed, it is necessary to optimize the frequency of the transmitted ultrasound pulse in accordance with local bone tissue conditions. As can be seen in signals 511 , 609 , and 710 , in which optimal transmission frequencies have been achieved, a signal optimally propagated through bone tissue comprises two parts: a transient process part (during which the amplitude and waveform of the signal are in flux) and a stationary part (during which a steady state waveform corresponding to the transmitted waveform is achieved). The phenomenon of frequency-induced wave distortion in bone tissue (as demonstrated above in the experiments of FIGS. 5, 6 , and 7 ) occurs due to a long transient process that occurs in solid, complex tissues. At a critical frequency, however, the duration of the transient process in the bone tissue becomes shorter than the pulse duration of the signal transmitted into the bone under interrogation. When this occurs, the bone becomes saturated by a transmitted wave of such a nature that the reflected wave will be identical in shape, and thus suitable for imaging analysis. (When the duration of the transient process in the bone tissue is longer than the pulse duration of the transmitted signal, however, the bone will be saturated in a manner that does not allow for meaningful analysis of the reflected wave.) It is at this critical frequency that the equalization of transmitted and received waveforms demonstrated in the experiments of FIGS. 5, 6 , and 7 occurs. The stationary part of the propagated signal is of importance inasmuch as it is the only component of the signal suitable for analysis so as to calculate signal time of flight and/or changes in amplitude precisely. High precision measurement of time of flight and/or amplitude can be performed by comparing the amplitude (positive, negative or peak-to-peak) of the first full wave in the stationary part of the received signal with the corresponding wave in the transmitted pulse. As is well known in the art, when measuring distances by means of time of flight calculations, it is desirable that the signal be as short as possible. When interrogating bone tissue with ultrasound it is thus desirable to utilize a transmitted signal which is as short as possible, yet long enough to establish a measurable stationary part. Turning now to FIG. 8, additional results of experimental transmission of ultrasonic signals, by a wide band ultrasonic crystal, into the same bone tissue as used in the experiments of FIGS. 5, 6 , and 7 are shown. The oscilloscope screenshots show the ultrasonic signal received by a second wide band ultrasonic crystal after transmission, into the bone tissue of a single ultrasonic pulse comprising seven waves. In all the demonstrated examples, the bone travel distance for the ultrasonic pulse was 20 mm and the attenuation of the ultrasonic wave on the surface of the bone tissue was 10 dB/cm at 0.5 MHz. The frequency of the first transmitted pulse (signal 511 ) was 0.55 MHz, and in each subsequent pulse (signals 801 through 805 ) the transmission frequency was decremented by 0.05 MHz at a time, as indicated in the figure. Thus, the first ultrasonic pulse transmitted, which resulted in reception of signal 511 , had a frequency corresponding to the upper limit for meaningful interrogation of the local bone tissue, while the quantity of transmitted full waves was sufficient to result in an easily detectable stationary part in received signal 511 , as described above. It is noteworthy that as the frequency of the transmitted ultrasonic pulse was decreased, the stationary part of the received signal became progressively more elongated (see signals 801 through 804 ). Signal 805 demonstrates that at a critical frequency (in this case 0.3 MHz) the waveform of the received signal became deformed in the zero cross area (that is, the point on the time axis where the signal is equal to zero, when passing from a positive value to a negative value, or vice-versa). When the multilayered bone tissue becomes fully saturated by the transmitted wave, the interferential wave (i.e. a complex wave consisting of multiple wave modes, similar to a Lamb wave, which is propagated through the tissue) becomes non-linear due to harmonics caused by oscillation of all the bone layers. This phenomenon, which is well described in non-linear acoustic theory, results in the deformatioll of the received wave, as observed in signal 805 . As deformation of this nature precludes meaningful analysis of the received signal and comparison with the transmitted signal, this critical frequency constitutes the lower limit for the frequency at which ultrasonic interrogation of this bone tissue can be meaningfully performed. Below this frequency, distortion of the pulse waveform renders calculation of amplitude and time delay unreliable. The value of this lower frequency limit depends on the properties of the particular bone tissue under interrogation (for example, ultrasonic attenuation in the bone) and on the bone travel distance (i.e. the distance between the scanning, crystals in the ultrasonic probe). It should also be noted in FIG. 8 that as the transmission frequency was decreased from 0.55 MHz to 0.35 MHz, the net travel times for signals 801 through 804 increased (as indicated by an elongation of the stationary part of the signal) and the amplitudes of the signals increased, even though the bone travel distance remained constant. This phenomenon, of ultrasound velocity and amplitude in bone tissue being dependent on the ultrasound transmission frequency, is a manifestation of two ultrasonic phenomena: 1. Due to the multiple tissue layers from which bone is structured, the mode of a propagated ultrasonic wave changes from being purely longitudinal to being a complex of different modes (referred to above as an interferential wave, similar to a Lamb wave) as it passes through bone tissue. As the nature of this wave-complex is dependent on the frequency of the transmitted wave, two transmitted waves of different frequency passing through the same bone, will have different travel times 2. Ultrasound waves of different frequencies possess different penetration capabilities, and thus different travel times. It will be well known to one familiar with linear and non-linear acoustic theory that an ultrasonic pulse transmitted into bone will be propagated within the bone tissue as a spectrum of frequencies, with the width of the spectrum being dependent on the shape of the pulse. A transmitted pulse can therefore be resolved into a number of sinusoids, each sinusoid having its own amplitude and frequency. Due to the above-described phenomenon of frequency dependent attenuation of the ultrasonic signal, the output signal will differ from the input signal in terms of its constituent sinusoid amplitudes and frequencies. These amplitudes and frequencies can be analyzed so as to derive information about the internal structure of the bone under investigation. Turning now to FIG. 9, an example of ultrasound velocity presented as a function of depth of penetration into bone tissue is shown. Two curves are shown in FIG. 9 Curve 901 corresponds to a first bone travel distance BTD1, being the distance between the transmitting and receiving crystals of a first ultrasonic probe, and curve 902 corresponds to a second bone travel distance BTD2, being the distance between the transmitting and receiving crystals of a second ultrasonic probe. Curves 901 and 902 both depict the results of ultrasonic transmission through the same bone tissue, with BTD1 being greater than BTD2. As shown, for a given BTD, changing the frequency of the transmitted pulse results in a different net travel time (i.e. a different ultrasound velocity) for the ultrasound signal. The upper and lower frequency limits for meaningful ultrasonic interrogation of the bone tissue, as described in the experiments of FIGS. 5, 6 , 7 , and 8 , are marked on the X axis of the graph. Initial penetration of the bone tissue commences when the transmission frequency is equal to the upper frequency limit (marked by a zero on the graph). At frequencies higher than this, incomplete penetration of the bone tissue by the transmitted pulse results in distortion of the received signal. Starting from the upper frequency limit, as the transmission frequency decreases the depth of penetration progressively increases, until such time as the lower frequency limit is achieved. At this point the bone tissue is fully saturated, and further decreasing the transmission frequency results in distortion of the received signal. As thicker bone tissue will become fully saturated at a lower transmission frequency than will thinner bone tissue, the thickness of a layer of bone tissue correlates with the difference between the observed upper and lower limits for appropriate transmission frequencies for a fixed bone travel distance (i.e. for an ultrasonic probe with a fixed distance between the scanning crystals). Furthermore, for a given transmission frequency, increased bone mineral density is associated with a decrease in the velocity of ultrasound within the bone tissue. Thus both thickness of the bone under investigation and its mineral density can be imaged in terns of the relationship between transmission frequency and measured ultrasound velocity. The reliability and quality of ultrasonic bone imaging can therefore be markedly improved by performing multifrequency measurements of travel times and/or amplitudes of signals passed through the bone tissue, alter adapting the frequency and duration of the transmitted pulse so as to achieve an optimal received signal (that is, a received signal of identical number of waves to that of the transmitted signal). The innovation of the current invention lies in achieving ultrasonic bone imaging by utilizing any or all of the following techniques (which have been demonstrated in the above experiments): 1. optimizing the transmitted signal frequency to an upper frequency limit such that the received signal is of an identical number of waves to that of the transmitted signal (so as to ensure that amplitude and time-of-flight calculations are meaningful) 2. optimizing the number of waves in the transmitted signal such that the received signal includes two consecutive waves of identical amplitude (so as to ensure that amplitude and time-of-flight calculations are meaningful) 3. determining a lower frequency limit for the transmitted signal such that the received signal begins to show distortion in the zero cross area (so as to image the thickness of bone tissue as a function of the difference between the upper and lower transmission frequency limits, and image the bone mineral density by measuring ultrasound velocity as a function of depth of penetration of the transmitted signal) 4. determining the amplitude and frequency spectrum of sinusoids of a received wave (so as to image bone characteristics as a function of sinusoidal frequency spectra). Referring now to the drawings, FIG. 10 is a block diagram of a first preferred embodiment of an ultrasonic apparatus for imaging bone tissue, generally designated 100 , constructed and operative according to the teachings of present invention. Ultrasonic apparatus 100 is similar to ultrasonic apparatus 10 and therefore common elements are denoted with similar reference numbers used to describe ultrasonic apparatus 10 . Hence, ultrasonic apparatus 100 includes ultrasonic probe 12 for transmitting ultrasonic pulses into bone 14 via soft tissue 16 , and for receiving reflected or transmitted signals therefrom. Ultrasonic apparatus 100 further includes digital computing device 18 for analyzing the received ultrasound signal and generating an image of bone 14 from the measured amplitude and/or time delay of the received signal. Ultrasonic apparatus 100 also includes display 20 for displaying the image generated by computing device 18 . It is a particular feature of apparatus 100 that ultrasonic probe 12 includes two wide band scanning crystals 122 and 124 . It should be noted that wide band scanning crystals differ significantly from resonant scanning crystals (which are used in the prior art), inasmuch as resonant scanning crystals exhibit the characteristic of frequency dependent transfer function. Consequently, when a resonant scanning crystal converts an acoustic signal into an electrical signal (or vice-versa), the resonance of the crystal itself interferes with the resonance of the received (or transmitted) signal. FIG. 11 illustrates the nature of this interference. As shown in the figure, the frequency of the signal output by a resonant scanning crystal is a summation of the frequency spectra of the received signal and the frequency spectra of the crystal itself. Thus, when standard resonant crystals are used to receive signals propagated through bone tissue, the response of the receiving crystal, rather than the response of the bone tissue alone, is measured, resulting in imprecise calculation of signal travel time and/or changes in amplitude. Wide band scanning crystals, however, convert acoustic signals into electrical signals (or vice-versa) with high fidelity, preserving the full frequency spectra of the received signal. An additional difference between wide band and resonant scanning crystals is that whereas resonant crystals oscillate at a fixed frequency, the transmission frequency of wide band crystals can be varied. Standard wide band scanning crystals of the type well described in the literature (Brown A. F. and Weight I. P. “Generation and reception of wide-band ultrasound”, published in Ultrasonics, 1974, v.12, No4, p.161-167, and Mitchell B. F. and Redwood M. “The generation of sound by nonuniform piezoelectric materials”, published in Ultrasonics, 1969, v.7, No7, p.123-129) are suitable for use as wide band scanning crystals 122 and 124 . Wide band scanning crystal 122 is operative to transmit ultrasonic pulses into bone 14 via soft tissue 16 , while wide band scanning crystal 124 is operative to receive the transmitted and reflected ultrasonic signals after having passed through bone 14 and soft tissue 16 . In terms of the teaching of the current invention, wide band scanning crystals 122 and 124 allow for tuning of the frequency of transmitted ultrasonic pulses, so as to optimize the frequency of transmitted ultrasound pulses according to local bone tissue conditions. Returning now to FIG. 10, inclined delay lines 26 and 28 equip scanning crystals 122 and 124 correspondingly. The values of ultrasound velocities for delay lines 26 and 28 are approximately equal to the value of ultrasound velocity in the soft tissue 16 . Delay line 26 directs scanning crystal 122 by the angle α providing propagation of ultrasonic wave along the surface of bone 14 . Delay line 28 directs the scanning crystal 124 by the same angle α providing optimal receiving of signal passed along the bone 14 . The net travel time for signal passed through bone 14 is determined by the following way: T 4 =T Σ −T 26 −T 28 −T 16 , here T 14 is the net travel time for signal passed through bone 14 ; T Σ is the delay of signal received by scanning crystal 24 with respect to ultrasonic pulse transmitted by scanning crystal 22 ; T 26 and T 28 are the propagation times of ultrasonic pulse in the delay lines 26 and 28 correspondingly; T 16 is the propagation time of ultrasonic pulse in the soft tissue 16 . The ultrasound velocity (SOS) in the bone 14 is determined by digital computing device by the following way: SOS = BTD T 14 Per the following reason: It is well known that V  [ m / sec ] = D    [ m ] T    [ sec ]  SOS is defined as velocity; BTD is defined as distance and T is defined as time. here BTD is the bone travel distance, which is determined by the distance between scanning crystals 122 and 124 and angle α. It is particular feature of ultrasonic apparatus 100 that digital computing device 18 includes a frequency selection mechanism 148 , by means of which the User of apparatus 100 may select a frequency at which ultrasonic pulses are to be transmitted by scanning crystal 122 , and a full wave quantity selection mechanism 152 , by means of which the user of apparatus 100 may select a quantity of full waves to constitute an ultrasonic pulse to be transmitted by scanning crystal 122 . Frequency selection mechanism 148 and full wave quantity selection mechanism 152 also receive input from components of digital computing device 18 (full waves quantity counting mechanism 146 and waveform analyzing mechanism 150 , as explained below) which can automatically determine the frequency at which ultrasonic pulses are to be transmitted, and the quantity of full waves to constitute each transmitted ultrasonic pulse. Frequency selection mechanism 148 and full wave quantity selection mechanism 152 input the selected frequency and number of full waves into a generator of electrical pulses 140 . Generator 140 is a functional generator operative to generate electrical pulses at the frequency defined by frequency selection mechanism 148 , and comprising the quantity of full waves defined by full wave quantity selection mechanism 152 . The electrical pulses generated by generator 140 are input to wide band scanning crystal 122 , resulting in the generation of an ultrasonic signal of the selected frequency and number of waves. The propagated ultrasonic wave passes through soft tissue 16 and bone tissue 14 , and is received by scanning ultrasonic crystal 124 . The received signal is then input to a first analogue to digital converter 142 , which is operative to digitize the waveforms of ultrasound signals received by wide band scanning crystal 124 . First analogue to digital converter 142 then inputs the digitized waveform to a first signal waveform memory 144 , which is operative to store digitized waveforms of received signals. A full waves quantity counting mechanism 146 then determines the quantity of full waves in the digitized waveform stored in first signal waveform memory 144 , and a waveform analyzing mechanism 150 analyzes the stored digitized waveform so as to identify at least two sequential full waves of equal amplitude in the received signal. Waveform analyzing mechanism 150 also determines the serial number, within the sequence of received waves, of the first full wave, that is, the first wave of maximal amplitude within the received signal. Digital computing device 18 is operative to compare the first wave of maximal amplitude, and subsequent waves, within the received signal, with the waves of corresponding serial numbers within the pulse transmitted by scanning crystal 122 . Waveform analyzing mechanism 150 also determines differentiation in the zero cross area of the waveform stored in first signal waveform memory 144 (dY/dX). Ultrasonic apparatus 100 functions as follows: The operator applies ultrasonic probe 12 to soft tissue 16 overlying bone tissue 14 under interrogation. An ultrasonic pulse of high frequency (for example, greater than 5 MHz) comprised of four waves is transmitted into bone tissue 14 . These initial transmission parameters are determined manually and empirically by the operator. The pulse is repeated at a pulse repetition frequency of approximately 1 kHz. The propagated signal is then received by probe 12 , after having passed through bone tissue 14 . Full waves quantity counting mechanism 146 counts the number of full waves in the received pulse, and compares this number to the number of full waves in the transmitted pulse. If the received pulse does not contain the same number of full waves (periods) as the transmitted pulse, full waves quantity counting mechanism 146 instructs frequency selection mechanism 148 to decrease the frequency of the transmitted pulse by 0.1 MHz. The pulse transmission and analysis is then repeated until such time as four waves are identified by full waves quantity counting mechanism 146 , at which point the transmission frequencies no longer decremented. Waveform analyzing mechanism 150 then analyzes the amplitudes (positive, negative or peak-to-peak) of each full wave in the received signal so as to determine if at least two sequential full waves of equal amplitude are present. Sequential waves are considered to be equal if the difference between them is approximately 1-3% or less. Waveform analyzing mechanism 150 then instructs full wave quantity selection mechanism 152 to incrementally increase the quantity of full waves in the transmitted pulse by one wave at a time, until such time as the received signal comprises a stationary part which contains at least two sequential full waves of equal amplitude to each other. The serial number of the first full wave in the sequence of full waves having equal amplitudes is determined by digital computing device 18 , and is compared with the full wave having the same serial number in the transmitted signal, so as to determine the attenuation and/or ultrasound velocity of the transmitted signal. The current transmission frequency is stored, and digital computing device 18 then progressively decreases the frequency of the transmitted pulse until such time as waveform analyzing mechanism 150 detects distortion of the received waveform in the zero cross area (by determining that the differential of the received signal in the zero cross area is equal to zero). The transmission frequency at which this occurs is stored, and digital computing device 18 analyzes the upper and lower frequency limits, as detected, and generates an image of the thickness of bone 14 from the acquired ultrasonic data. Finally, the frequency spectra of the sinusoids constituting all the received signals which had been transmitted within the upper and lower frequency limits are analyzed by digital computing device 18 , and, in an iterative process, an image of bone 14 is generated from the acquired ultrasonic data. The generated image or images are then displayed on display 20 . Turning now to FIG. 12, a second preferred embodiment of an ultrasonic apparatus for evaluating bone tissue, generally designated 1000 , is schematically depicted. Ultrasonic apparatus 1000 is similar to ultrasonic apparatus 100 and therefore common elements are denoted with the same reference numbers as used to describe ultrasonic apparatus 10 and apparatus 100 above. The components of apparatus 1000 which are designated with the same numbers as referred to above regarding apparatus 100 have identical structure and function to that previously described, such that only the additional elements of apparatus 1000 , which do not appear in apparatus 100 , will be described. It is particular feature of ultrasonic apparatus 1000 that ultrasonic probe 12 further includes a third wide band scanning crystal 154 equipped with a delay line 156 . Wide band scanning crystal 154 is placed in proximity to receiving wide band scanning crystal 124 (separated by approximately 3 mm), but more distant from transmitting scanning crystal 122 than is receiving scanning crystal 124 , and oriented parallel to receiving scanning crystal 124 . The distance between wide band scanning crystal 154 and wide band scanning crystal 124 is equal to the difference between the travel distances of ultrasonic signals received by crystals 154 and 124 correspondingly, and is designated ABTD. Delay lines 28 and 156 are identical, thus the ultrasound velocity (SOS) in bone 14 can be calculated by digital computing device 18 using the following formula: SOS = Δ     BTD Δ     T 14 Per the following reason: It is well known that V  [ m / sec ] = D    [ m ] T    [ sec ]  SOS is defined as velocity; BTD is defined as distance and T is defined as time. where ΔT is the time delay between reception of the ultrasonic signal by wide band scanning crystal 154 and by wide band scanning crystal 124 . The addition of third wide band scanning crystal 154 to apparatus 1000 obviates the need to determine propagation times for delay lines 26 and 28 and for soft tissue 16 , when calculating the ultrasound velocity in bone tissue 14 . As such, the accuracy and repeatability of ultrasonic evaluation of bone tissue is increased. It is particular feature of ultrasonic apparatus 1000 that it further includes a second analogue to digital converter 158 , operative to digitize the waveforms received by third wide band scanning crystal 154 . Second analogue to digital converter 158 then outputs the digitized waveforms to a second signal waveform memory 160 , which stores the digitized waveforms of signals received by third wide band scanning crystal 154 . When ultrasonic probe 12 is oriented optimally with regard to bone tissue 14 , the signals received by scanning crystals 124 and 154 will be identical. Thus, a correlation determining mechanism 162 computes a correlation coefficient between the signals stored in memories 144 and 160 . A correlation threshold selection mechanism 164 is operative to receive as input from the user a correlation threshold value empirically selected by the user, and to compare that selected value until the correlation coefficient calculated by correlation determining mechanism 162 . An example of a typical correlation threshold is 0 . 95 . When the calculated correlation coefficient is above the selected correlation threshold value, digital computing device 18 processes the acquired ultrasonic signals, as described above, so as to generate imaging data for bone tissue 14 . However, when the calculated correlation coefficient is below the selected correlation threshold value, digital computing device 18 ceases image processing functions and/or sounds a warning signal alerting the user to the possibility that ultrasonic probe 12 is not optimally applied. Thus, ultrasonic apparatus 1000 improves the repeatability of results of ultrasonic evaluation of bone tissue by providing real time feedback to the operator regarding the orientation of ultrasonic probe 12 on the patients body. This feedback is based on the ultrasound signals actually received by probe 12 and used for imaging of bone tissue 14 . While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other application of the invention may be made. There has therefore been described a method and device for imaging bone tissue ultrasonically which allows for the precise and easily repeatable measurement of ultrasonic travel time and signal amplitude, the imaging of the internal structure of bone tissue, and the optimization of probe orientation by directly utilizing the imaging signals received from the bone.

A method and system for ultrasonic imaging of bone tissue. A wide band scanning crystal transmits an ultrasonic signal of high frequency and multiple full waves into the bone tissue, and a second wide band scanning crystal receives the transmitted signal. The transmission frequency is progressively decreased until the number of full waves in the received signal equals that of the transmitted signal. At that frequency, the upper frequency limit, the number of full waves in the transmitted signal is gradually increased until the received signal contains at least two consecutive full waves of equal amplitude. The resultant transmission signal is then used to measure signal attenuation and velocity in bone tissue, in terms of standard bone imaging techniques. A lower frequency limit, below which the received signal undergoes distortion, is defined, and ultrasonic velocity depicted as a function of transmission frequency. Received ultrasonic wave frequency spectra, and the difference between the upper and lower frequency limits, are all used to image the bone tissue. Probe orientation is enhanced by a mechanism whereby a third wide band screening crystal receives the transmitted signal concomitantly with the second screening crystal. The signals received by the two wide band scanning crystals are correlated with each other to give a numerical indicator of the adequacy of probe orientation.

This application is a continuation application of U.S. application Ser. No. 09/780,492 filed on Feb. 12, 2001, now U.S. Pat. No. 6,593,920. BACKGROUND OF THE INVENTION The present invention relates to a level converter circuit and a liquid crystal display device employing the level converter circuit, and in particular to a level converter circuit formed by polysilicon transistors. Liquid crystal display modules of the STN (Super Twisted Nematic) type or the TFT (Thin Film Transistor) type are widely used as a display device for a notebook personal computer and the like. Some driver circuits for driving such liquid crystal display panels need a level converter circuit external to the liquid crystal display panel. Such a level converter circuit is disclosed in Japanese Patent Application Laid-open No. Hei 6-204,850 (laid-open on Jul. 22, 1994), for example. FIG. 13 is a circuit diagram of an example of a prior art level converter circuit. The level converter circuit shown in FIG. 13 is formed by MOS transistors using single crystal silicon for their semiconductor layers, and is of the same circuit configuration as that shown in FIG. 4 of Japanese Patent Application Laid-open No. Hei 6-204,850. The level converter circuit shown in FIG. 13 has a CMOS inverter INV 1 to which a low-voltage input signal φ 1 is supplied and a CMOs inverter INV 2 to which an output signal φ 2 from the CMOS inverter INV 1 is supplied. The CMOS inverter INV 1 is formed by a p-channel MOS transistor (hereinafter referred to as a PMOS) M 5 and an n-channel MOS transistor (hereinafter referred to as an NMOS) M 6 which are connected in series between a low voltage VCC and a reference voltage (or ground potential) Vss. The CMOS inverter INV 2 is formed by a PMOS M 7 and an NMOS M 8 which are connected in series between the low voltage VCC and the reference voltage (or ground potential) Vss. Further, the level converter circuit includes a series combination of a PMOS M 9 and an NMOS M 11 and a series combination of a PMOS M 10 and an NMOS M 12 , which are connected between a high voltage VDD and the reference voltage VSS. An output signal φ 3 from the CMOS inverter INV 2 is supplied to a gate electrode of the NMOS M 11 , and an output signal φ 2 from the CMOS inverter INV 1 is supplied to a gate electrode of the NMOS M 12 . A gate electrode of the PMOS M 9 is connected to a drain electrode of the PMOS M 10 , and a gate electrode of the PMOS M 10 is connected to a drain electrode of the PMOS M 9 . The input signal φ 1 supplied via an input terminal VIN has an amplitude between the low voltage VCC and the reference voltage VSS, and is converted into the low voltage outputs φ 2 and φ 3 each having amplitudes between the low voltage VCC and the reference voltage VSS. The low voltage output signals φ 2 and φ 3 are supplied to gate electrodes of the NMOS M 11 and the NMOS M 12 , respectively, and outputs from output terminals VOUT 1 and VOUT 2 are two level-converted signals, that is, two complementary output signals φ 4 and φ 5 having amplitudes between the high supply voltage VDD and ground potential VSS, respectively. For example, suppose that the low voltage output signal φ 2 is at a high level (hereafter referred to merely as an H level) and the low voltage output signal φ 3 is at a low level (hereafter referred to merely as an L level). Then the NMOS M 12 is ON, PMOS M 9 is ON, NMOS M 11 is OFF, and PMOS M 10 is OFF, and therefore the output terminal VOUT 2 outputs the ground potential VSS and the output terminal VOUT 1 outputs the high voltage VDD. Next, suppose that the low voltage output signal φ 2 is at the L level and the low voltage output signal φ 3 is at the H level. Then the NMOS M 12 is OFF, the PMOS M 9 is OFF, the NMOS M 11 is ON, and the PMOS M 10 is ON, and therefore the output terminal VOUT 2 outputs the high supply voltage VDD and the output terminal VOUT 1 outputs the ground potential VSS. FIG. 14 is a circuit diagram of another example of a prior art level converter circuit. The level converter circuit shown in FIG. 14 is also formed by MOS transistors using single crystal silicon for their semiconductor layers, and is of the same circuit configuration as that shown in FIG. 1 of Japanese Patent Application Laid-open No. Hei 6-204,850. The level converter circuit shown in FIG. 14 differs from that shown in FIG. 13 , in that the CMOS inverter INV 2 is omitted, the output signal φ 2 from the CMOS inverter INV 1 is supplied to the source electrode of the NMOS M 11 , and the gate of which is supplied with the low voltage VCC. In the level converter circuit shown in FIG. 13 , when the level-converted output signals φ 4 , φ 5 from the output terminals VOUT 1 , VOUT 2 change from the H level to the L level, or from the L level to the H level, all of the PMOS M 9 , the NMOS M 11 , the PMOS M 10 and the NMOS M 12 are turned ON simultaneously, and consequently, currents flow through a series combination of the PMOS M 9 and the NMOS M 11 and a series combination of the PMOS M 10 and the NMOS M 12 , respectively. The level converter circuit shown in FIG. 14 is configured so as to prevent such currents from flowing through the series combination of the PMOS M 9 and the NMOS M 11 and the series combination of the PMOS M 10 and the NMOS M 12 . The level converter circuit shown in FIG. 13 needs a total of eight MOS transistors comprising four MOS transistors M 5 to M 8 in the low-voltage circuit and four MOS transistors M 9 to M 12 in the high-voltage circuit, the level converter circuit shown in FIG. 14 needs six MOS transistors, and therefore the prior art level converter circuits had the problem in that many MOS transistors are needed. It is known that mobility in MOS transistors using as their semiconductor layers, single crystal silicon, polysilicon and amorphous silicon are 1,000 to 2,000 cm 2 /(V·s), 10 to 100 cm 2 /(V·s), and 0.1 to 10 cm 2 /(V·s), respectively. MOS transistors using as their semiconductor layers, polysilicon and amorphous silicon are capable of being fabricated on a transparent insulating substrate made of quartz glass or glass having a softening temperature not higher than 800° C., and therefore electronic circuits can be fabricated directly on a display device such as a liquid crystal display device. FIG. 15 is a graph showing an example of switching characteristics of an n-channel MOS transistor having a semiconductor made of single crystal silicon, and FIG. 16 is a graph showing an example of switching characteristics of an n-channel MOS transistor having a semiconductor layer made of polysilicon. In FIGS. 15 and 16 , curves A represent characteristics for a standard threshold VTH, curves B represent characteristics for a threshold voltage VTH shifted by −1 V from the standard threshold voltage, and curves C represent characteristics for a threshold voltage VTH shifted by +1 V from the standard threshold voltage. As is understood from FIGS. 15 and 16 , in the case of the polysilicon MOS transistor (a polysilicon thin film transistor, for example) using as a semiconductor layer a polysilicon obtained by a solid phase epitaxy method crystallizing at a temperature of 500° C. to 1,100° C., or a polysilicon obtained by crystallizing by laser-annealing amorphous silicon produced by a CVD method, when a gate-source voltage VGS is small (5 V or less), drain currents ID of the polysilicon MOS transistor is smaller than those of the MOS transistor having the semiconductor layer of single crystal silicon, and drain currents ID of the polysilicon MOS transistor vary greatly with variations of the threshold voltages VTH. As a result, when the level converter circuits shown in FIGS. 13 and 14 are formed by MOS transistors having semiconductor layers made of single crystal silicon, satisfactory operation can be guaranteed, but when the level converter circuits shown in FIGS. 13 and 14 are formed by polysilicon MOS transistors having semiconductor layers made of polysilicon, there was a disadvantage that sufficient driving capability could not be obtained in a case where the supply voltage is the low voltage VCC. FIG. 17 is a graph showing DC transfer characteristics of a CMOS inverter. In general, in a CMOS inverter, threshold voltages VTH are determined in the p-channel MOS transistors and the N-channel MOS transistors forming the CMOS inverter such that, when an input signal exceeds the middle between the H level and the L level of the input signals, the p-channel and N-channel MOS transistors forming the CMOS inverter change from ON to OFF, or from OFF to ON. Curve A in FIG. 17 represent the DC transfer characteristic in this state. Curve B in FIG. 17 represents a DC transfer characteristic in a case where the threshold voltages VTH of the p-channel and N-channel MOS transistors forming the CMOS inverter is shifted to the left of the curve A, and curve C in FIG. 17 represents a DC transfer characteristic in a case where the threshold voltages VTH of the p-channel and N-channel MOS transistors forming the CMOS inverter is shifted to the right of the curve A. FIGS. 18A to 18D are schematic illustrations for explaining input and output waveforms of the CMOS inverter. FIG. 18A represents a waveform of an input signal to the CMOS inverter, FIGS. 18B to 18D represent waveforms of output signals from the CMOS inverters having DC transfer characteristics corresponding to the curves A to C of FIG. 17 , respectively. If the DC transfer characteristic of the CMOS inverter is represented by the curve A of FIG. 17 , the output signal starts to fall delayed by a time tDA from the time the input signal starts to rise, but a duration LHA of the H level and a duration LLA of the L level of the output signal are the same as durations of the H and L levels of the input signal, respectively, as shown in FIG. 18B . But, if the DC transfer characteristic of the CMOS inverter is represented by the curve B of FIG. 17 , the output signal starts to fall delayed by a time tDB which is shorter than the time tDA, from the time the input signal starts to rise, a duration LHB of the H level of the output signal is shorter than the duration of the H level of the input signal and a duration LLB of the L level of the output signal is longer than the duration of the L level of the input signal, as shown in FIG. 18C . And, if the DC transfer characteristic of the CMOS inverter is represented by the curve C of FIG. 17 , the output signal starts to fall delayed by a time tDC which is longer than the time tDA, from the time the input signal starts to rise, and a duration LHC of the H level of the output signal is longer than the duration of the H level of the input signal and a duration LLC of the L level of the output signal is shorter than the duration of the L level of the input signal, as shown in FIG. 18D . In general, threshold voltages VTH of polysilicon MOS transistors vary more greatly than those of MOS transistors having single crystal silicon layer, and as is apparent from FIG. 16 , drain currents ID vary greatly with variations of threshold voltages VTH of the polysilicon MOS transistors. As a result, if the prior art level converter circuit is formed by polysilicon MOS transistors, the DC transfer characteristics of the CMOS inverters INV 1 , INV 2 (see FIG. 13 ) vary greatly mainly due to the variations of the threshold voltages VTH of the polysilicon MOS transistors of the CMOS inverters INV 1 , INV 2 , and consequently, there was a problem in that a delay time (or a phase difference) of the output signal with respect to the input signal and a variation of a duration of the H or L level of the output signal increase. For example, FIG. 19 shows waveforms of input and output signals of the level converter circuit of FIG. 13 formed by n-channel MOS transistors using polysilicon having mobility of about 80 cm 2 /(V·s) and p-channel MOS transistors using polysilicon having mobility of about 60 cm 2 /(V·s). In FIG. 19 , curve φ 5 represents an output of the level converter circuit having standard threshold voltages VTH, curve φ 5 - 1 represents an output of the level converter circuit in a case where threshold voltages VTH of the NMOS and PMOS transistors shift by −1 V, and curve φ 5 - 2 represents an output of the level converter circuit in a case where threshold voltages VTH of the NMOS and PMOS transistors shift by +1 V. As is apparent from FIG. 19 , the delay time of the output signal with respect to the input signal and a variation of a duration of the H level of the output signal vary greatly with the variations of the threshold voltages VTH of the MOS transistors. In a liquid crystal display module of the analog-sampling active-matrix type using polysilicon MOS transistors, such variations of the delay time of the output signal from the level converter circuit and the duration of the H level of the output signal cause a degradation in picture quality such as a picture defect in the form of a vertical line, when a half tone picture is displayed. FIG. 20 is an illustration for explaining a principle of displaying by the liquid crystal display module of the active matrix type using polysilicon MOS transistors. In the liquid crystal display module of the active matrix type using polysilicon MOS transistors, during one horizontal scanning period, a gate electrode line G 1 , for example, is selected by a scanning circuit and during this period analog video signals φsig are sampled and supplied to, . . . an (n−1)st drain electrode line, an nth drain electrode line, an (n+1)st drain electrode line, . . . , sequentially by shift scanning of shift registers SR of a horizontal scanning circuit, and this horizontal scanning is repeated the number of times equal to the number of the gate electrode lines to form a picture. The operation of sampling the analog video signals φsig for the (n−1)st, nth and (n+1)st drain electrode lines will be explained by referring to time charts in FIG. 21 . First, voltage levels of complementary clock input signals φPL and φNL are level-converted by level converter circuits LV 1 and LV 2 , respectively, to produce level-converted mutually complementary signals φNH and φPH. The signal φPH and an output from one shift register SR are supplied to a NAND circuit NA 1 to produce a sampling pulse φN, and the signal φNH and an output from another shift register SR are supplied to a NAND circuit NA 2 to produce a sampling pulse φN+1. The inverted pulses /φN and /φN+1 (A slant “/” is used instead of the bar “-” to indicate an inverted signal.) of the sampling pulses φN and φN+1 drive sample-and-hold circuits SH 1 and SH 2 to sample time-varying analog video signals φsig sequentially and supply video signal voltages φm−1, φm and φm+1 to the (n−1)st, nth and (n+1)st drain electrode lines. As a result, if the threshold voltages VTH of the MOS transistors of the level converter circuits LV 1 and LV 2 vary, the phases and the durations of the H level of the complementary signals φNH and φPH level-converted by the level converter circuits LV 1 and LV 2 vary, and consequently, the phases and the durations of the H level of the sampling pulses φN and φN+1 vary. The variations of the phases and the durations of the H level of the sampling pulses φN and φN+1 cause shortening of the sampling time, sampling of a portion of the analog video signal φsig different from a portion of the analog video signal φsig intended to be sampled, or overlapping of the sampling times of the two sampling pulses φN and φN+1. These produce a ghost in an image displayed on a liquid crystal display panel, and therefore deteriorate display quality of the displayed image extremely. In a digital-signal-input type liquid crystal display module of the active matrix type using polysilicon MOS transistors, if such level converter circuits are employed before a digital-analog converter (a D/A converter), variations of delay times occur in level converter circuits corresponding to respective data bits and consequently, a false picture is produced because some data bits are digital-to-analog converted in a state where they are inverted. SUMMARY OF THE INVENTION The present invention is made so as to solve the above problems with the prior art, it is an object of the present invention to provide a technique capable of operating a level converter circuit at a high speed and stably irrespective of variations of threshold voltages of transistors. It is another object of the present invention to provide a technique capable of improving the quality of displayed images by a liquid crystal display device by using the above level converter circuit. The above-mentioned and other objects and novel features of the present invention will be made apparent by the following description and accompanying drawings. The following explains the representative ones of the present inventions briefly. In accordance with an embodiment of the present invention, there is provided a level converter circuit comprising: an input terminal adapted to be supplied with a signal swinging from a first voltage to a second voltage lower than the first voltage; a first transistor having a gate electrode connected to the input terminal, and a source electrode connected to ground potential; a second transistor having a gate electrode connected to a drain electrode of the first transistor, a source electrode connected to a supply voltage, and a drain electrode connected to an output terminal; a load circuit connected between the gate electrode of the second transistor and the supply voltage; a third transistor having a source electrode connected to the input terminal, a drain electrode connected to the output terminal, and a gate electrode supplied with a DC voltage higher than the second voltage and lower than the first voltage, wherein the level converter circuit outputs a third voltage higher than the second voltage when the input terminal is supplied with the first voltage, and the level converter circuit outputs the second voltage when the input terminal is supplied with the second voltage. In accordance with another embodiment of the present invention, there is provided a level converter circuit comprising: an input terminal adapted to be supplied with a digital signal swinging from a first voltage to a second voltage lower than the first voltage; a first transistor having a gate electrode connected to the input terminal, and a source electrode connected to ground potential; a second transistor having a gate electrode connected to a drain electrode of the first transistor, a source electrode connected to a supply voltage, and a drain electrode connected to an output terminal; a load circuit connected between the gate electrode of the second transistor and the supply voltage; a third transistor having a source electrode connected to the input terminal, a drain electrode connected to the output terminal, and a gate electrode supplied with a DC voltage higher than the second voltage and lower than the first voltage, wherein (a) when the input terminal is supplied with the first voltage, the first transistor and the second transistor are ON, and the level converter circuit outputs a third voltage higher than the first voltage; and (b) when the input terminal is supplied with the second voltage, the first transistor and the second transistor are OFF and the level converter circuit outputs the second voltage via the third transistor. In accordance with still another embodiment of the present invention, there is provided a liquid crystal display device including a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, a plurality of pixels formed between the pair of substrates and a driver circuit for driving the plurality of pixels, the driver circuit being provided with a level converter circuit, the level converter circuit comprising: an input terminal adapted to be supplied with a digital signal swinging from a first voltage to a second voltage lower than the first voltage; a first transistor of an n-channel type having a gate electrode connected to the input terminal, and a source electrode connected to ground potential; a second transistor of a p-channel type having a gate electrode connected to a drain electrode of the first transistor, a source electrode connected to a supply voltage, and a drain electrode connected to an output terminal; a load circuit connected between the gate electrode of the second transistor and the supply voltage; a third transistor having a source electrode connected to the input terminal, a drain electrode connected to the output terminal, and a gate electrode supplied with a DC voltage, the DC voltage being such that, (a) when the source electrode of the third transistor is supplied with the second voltage, the third transistor is ON, and (b) when the source electrode of the third transistor is supplied with the first voltage, the third transistor is OFF, wherein (i) when the input terminal is supplied with the first voltage, the first transistor and the second transistor are ON, and the level converter circuit outputs a third voltage higher than the first voltage; and (ii) when the input terminal is supplied with the second voltage, the first transistor and the second transistor are OFF and the level converter circuit outputs the second voltage via the third transistor. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, in which like reference numerals designate similar components throughout the figures, and in which: FIG. 1 is a circuit diagram of a level converter circuit of Embodiment 1 of the present invention; FIG. 2 is an illustration of examples of input and output signal waveforms of the level converter circuit of Embodiment 1 of the present invention; FIG. 3 is a circuit diagram of a modification of the level converter circuit of Embodiment 1 of the present invention; FIG. 4 is a circuit diagram of another modification of the level converter circuit of Embodiment 1 of the present invention; FIG. 5 is a circuit diagram of still another modification of the level converter circuit of Embodiment 1 of the present invention; FIG. 6 is a circuit diagram of still another modification of the level converter circuit of Embodiment 1 of the present invention; FIG. 7 is a circuit diagram of still another modification of the level converter circuit of Embodiment 1 of the present invention; FIG. 8 is a circuit diagram of a level converter circuit of Embodiment 2 of the present invention; FIG. 9 is a circuit diagram of a level converter circuit of Embodiment 3 of the present invention; FIG. 10 is a circuit diagram of a level converter circuit of Embodiment 4 of the present invention; FIG. 11 is a block diagram representing a configuration of a display panel of an active-matrix type liquid crystal display module of the analog-sampling type using polysilicon MOS transistors in accordance with Embodiment 5 of the present invention; FIG. 12 is a block diagram representing a configuration of a display panel of a liquid crystal display module of the digital-signal-input active-matrix type using polysilicon MOS transistors in accordance with Embodiment 5 of the present invention; FIG. 13 is a circuit diagram of an example of a prior art level converter circuit; FIG. 14 is a circuit diagram of another example of a prior art level converter circuit; FIG. 15 is a graph showing an example of switching characteristics of a n-channel MOS transistor having a semiconductor made of single crystal silicon; FIG. 16 is a graph showing an example of switching characteristics of a MOS transistor having a semiconductor layer made of polysilicon; FIG. 17 is a graph showing DC transfer characteristics of a CMOS inverter; FIG. 18A is an illustration of a waveform of an input signal to a CMOS inverter, and FIGS. 18B to 18D are illustrations of waveforms of output signals from the CMOS inverter; FIG. 19 is an illustration of an example of waveforms of input and output signals of the level converter circuit of FIG. 13 formed by polysilicon n-channel MOS transistors and polysilicon p-channel MOS transistors; FIG. 20 is an illustration for explaining a principle of displaying by a liquid crystal display module of the active matrix type using polysilicon MOS transistors; FIG. 21 is timing charts for explaining the operation of sampling analog video signals φsig to be supplied to a drain electrode line in FIG. 20 ; and FIG. 22 is a circuit diagram of a prior art buffer circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be explained in detail by reference to the drawings. All the drawings for the embodiments use the same reference numerals to identify parts performing the same functions, which are not repeatedly described in the specification. Embodiment 1 FIG. 1 is a circuit diagram representing a level converter circuit of Embodiment 1 of the present invention. As shown in FIG. 1 , the level converter circuit of this embodiment is formed by a total of transistors including two enhancement-mode p-channel polysilicon MOS transistors and two enhancement-mode n-channel polysilicon MOS transistors, and the level converter circuit has a first stage formed by PMOS M 1 and NMOS M 3 and a second stage formed by PMOS M 2 and NMOS M 4 . A source electrode of NMOS M 3 of the first stage is connected to the reference voltage VSS (ground potential) and a gate electrode of NMOS M 3 is supplied with an input signal φ 6 from a input terminal VIN. The input signal φ 6 has an amplitude of VCC, or varies from a voltage higher than VCC to ground potential VSS. A drain electrode of PMOS M 1 is connected to a drain electrode of NMOS M 3 , and a source electrode and a gate electrode of PMOS M 1 are connected to the high voltage VDD and its drain electrode, respectively. A source electrode of NMOS M 4 of the second stage is supplied with the input signal φ 6 and a gate electrode of NMOS M 4 is connected to a low voltage VCC. A drain electrode of PMOS M 2 is connected to a drain electrode of NMOS M 4 , and a source electrode and a gate electrode of PMOS M 2 are connected to the high voltage VDD and the drain electrode of PMOS M 1 , respectively. Namely, PMOS M 1 forms an active load. A level-converted output signal φ 8 is output from the drain electrode of PMOS M 2 of the second stage. In the level converter circuit of this embodiment, among electrodes of NMOS M 3 and M 4 of the first and second stages, all the electrodes (i.e., the source and gate electrodes of NMOS M 3 and the source and gate electrodes of NMOS M 4 ) except for electrodes connected to an output terminal or a next stage are supplied with the input signal φ 6 or a direct-current voltage (the low voltage VCC or ground potential VSS). Next, the operation of the level converter circuit of this embodiment will be explained. When the input signal φ 6 from the input terminal VIN is at the H level, NMOS M 3 is ON, PMOS M 1 is ON, NMOS M 4 is OFF, PMOS M 2 is ON, and therefore the output terminal VOUT outputs the high voltage VDD. When the input signal φ 6 is at the L level, NMOS M 3 is OFF, PMOS M 1 is OFF, NMOS M 4 is ON, PMOS M 2 is OFF, and therefore the output terminal VOUT outputs the input signal φ 6 which is at the L level. FIG. 2 is illustrations of examples of waveforms of the input and output signals of the level converter circuit of this embodiment. FIG. 2 illustrates the waveforms of the input and output signals in a case where polysilicon n-channel MOS transistors having mobility of about 80 cm 2 /(V·s) are used as NMOS M 3 and M 4 , and polysilicon p-channel MOS transistors having mobility of about 60 cm 2 /(V·s) are used as PMOS M 1 and M 2 . In FIG. 2 , curve φ 8 represents a waveform of an output in a case where NMOS M 3 , M 4 and PMOS M 1 , M 2 have standard threshold voltages VTH, curve φ 8 - 1 represents a waveform of an output in a case where NMOS M 3 , M 4 and PMOS M 1 , M 2 have threshold voltages changed by −1 V, and curve φ 8 - 2 represents a waveform of an output in a case where NMOS M 3 , M 4 and PMOS M 1 , M 2 have threshold voltages changed by +1 V. As is apparent from FIG. 2 , the level converter circuit of this embodiment provides comparatively stable input and output characteristics irrespective of the variations of the threshold voltages VTH of NMOS M 3 , M 4 and PMOS M 1 , M 2 , compared with the waveforms of the input and output characteristics shown in FIG. 19 . As described above, the threshold voltages VTH of the polysilicon MOS transistors vary greatly, and as shown in FIG. 16 , when the supply voltage is low, the drain currents ID vary greatly with the variations of the threshold voltages VTH of the MOS transistors. However, in the level converter circuit of this embodiment, the external signal φ 6 is applied to the gate electrode of NMOS M 3 and the source electrode of NMOS M 4 directly from the input terminal VIN, and as a result, even if the threshold voltages VTH of the polysilicon MOS transistors vary, the drain currents ID do not vary much. Consequently, the level converter circuit of this embodiment can prevent the delay time of the output signal and the duration of the H level of the output signal from varying greatly with the variations of the threshold voltages VTH of the transistors NMOS M 3 , M 4 and PMOS M 1 , M 2 forming the level converter circuit. Incidentally, the advantages of this embodiment are obtained in a level converter circuit using transistors having single-crystal semiconductor layers. However, as shown in FIG. 15 , the threshold voltages VTH of the MOS transistors having a single-crystal semiconductor layer do not vary much, and a large amount of the drain currents can be obtained, and consequently, it is common sense to use a conventional circuit shown in FIG. 13 for the purpose of low power consumption. Therefore no one has thought of the level converter circuit of this embodiment shown in FIG. 1 , because there is a disadvantage of increase of power consumption. FIGS. 3 to 7 are circuit diagrams for illustrating modifications of the level converter circuit of the embodiment of the present invention. A level converter circuit shown in FIG. 3 uses a resistor element as a load of its first stage. In the level converter circuit of FIG. 3 , the same polysilicon film and wiring electrodes as those of the thin film transistors (TFTs) can be used for the resistor element, and as a result, the level converter circuit can be fabricated simply and manufactured easily. A level converter circuit shown in FIG. 4 uses as a load of its first stage a polysilicon PMOS M 1 a gate electrode of which is supplied with a specified bias supply voltage Vbb. In the level converter circuit of FIG. 4 , a current flowing through NMOS M 3 is limited by PMOS M 1 , and consequently, its power consumption is suppressed. The limit of the current is determined by the bias supply voltage Vbb. A level converter circuit shown in FIG. 5 uses as a load of its first stage an active load formed by a polysilicon NMOS M 20 . In the level converter circuit of FIG. 5 , an input stage is formed only by MOS transistors of NMOS M 3 and M 20 , and the NMOS transistors have higher mobility than PMOS transistors and therefore the level converter circuit operates with greater speed. A level converter circuit shown in FIG. 6 uses as a load of its first stage an active load formed by a depletion-mode polysilicon NMOS M 21 . In the level converter circuit of FIG. 6 , NMOS M 21 is a depletion-mode MOS transistor, and it can flow a current therethrough at all times and therefore the level converter circuit operates with greater speed, but the power consumption is increased accordingly. A level converter circuit shown in FIG. 7 uses a diode D as a load of its first stage. The diode D is fabricated by doping the same polysilicon film as that of the thin film transistors (TFT) with impurities for forming a p-type region and an n-type region, respectively, and therefore the level converter circuit of FIG. 7 facilitates its manufacturing process. The level converter circuits shown in FIGS. 3 to 7 are capable of providing the advantages similar to those provided by the level converter circuit of FIG. 1 . Embodiment 2 FIG. 8 is a circuit diagram of a level converter circuit of Embodiment 2 of the present invention. As shown in FIG. 8 , the level converter circuit of this embodiment also uses a total of four enhancement-mode transistors including two p-channel polysilicon MOS transistors and two n-channel polysilicon MOS transistors, and has the first stage formed by PMOS M 1 and NMOS M 3 and the second stage formed by PMOS M 2 and NMOS M 4 . The level converter circuit of this embodiment differs from that of Embodiment 1, in that a source electrode of NMOS M 3 of the first stage is supplied with the input signal φ 6 , a gate electrode of NMOS M 3 is connected to the low voltage VCC, a source electrode of NMOS M 4 of the second stage is connected to the reference voltage VSS and a gate electrode of NMOS M 4 is supplied with the input signal φ 6 from the input terminal VIN. In the level converter circuit of this embodiment, when the input signal φ 6 from the input terminal VIN is at the H level, NMOS M 3 is OFF, PMOS M 1 is OFF, NMOS M 4 is ON, PMOS M 2 is OFF, and therefore the output terminal VOUT outputs ground potential VSS. Next, when the input signal φ 6 is at the L level, NMOS M 3 is ON, PMOS M 1 is ON, NMOS M 4 is OFF, PMOS M 2 is ON, and therefore the output terminal VOUT outputs the high voltage VDD. While, in the level converter circuit of Embodiment 1, the level-converted output signal φ 8 is in the same phase with the input signal φ 6 , the level-converted output signal φ 8 of the level converter circuit of this embodiment is in the phase opposite from the input signal φ 6 . The level converter circuit of this embodiment also provides the advantages similar to those provided by the level converter circuit of Embodiment 1, and the level converter circuit of Embodiment 2 may use one of the loads represented in FIGS. 3 to 7 , as the load of the first stage which is formed by PMOS M 1 . A buffer circuit similar to the level converter circuit of Embodiment 2 is disclosed in Japanese Patent Application Laid-open No. Hei 7-7414 (laid-open on Jan. 10, 1995). FIG. 22 is a circuit diagram of the buffer circuit disclosed in Japanese Patent Application Laid-open No. Hei 7-7414. Only the voltage VDD and the reference voltage VSS are supplied to the buffer circuit of FIG. 22 including PMOS Q 1 and NMOS Q 2 so as to perform a function of the buffer circuit. NMOS Q 2 is supplied with a signal having an amplitude varying between the voltage VDD and ground potential VSS, and consequentially, a depletion-mode n-channel MOS transistor is used as NMOS Q 2 . In the first place, the buffer circuit of FIG. 22 is not a level converter circuit for shifting a voltage level of an input signal, and it differs from the level converter circuit of Embodiment 2 in that the depletion-mode n-channel MOS transistor, NMOS Q 2 , is used. Further, Japanese Patent Application Laid-open No. Hei 7-7414 does not disclose a technique for preventing the delay time of the output signal and the duration of the H level of the output signal from varying greatly with variations of the threshold voltages VTH of the transistors NMOS M 3 , M 4 and PMOS M 1 , M 2 of the level converter circuit of Embodiment 2 shown in FIG. 8 . Embodiment 3 FIG. 9 is a circuit diagram of a level converter circuit of Embodiment 3 of the present invention. As shown in FIG. 9 , the level converter circuit of this embodiment also uses a total of four enhancement-mode transistors including two p-channel polysilicon MOS transistors and two n-channel polysilicon MOS transistors, and has the first stage formed by PMOS M 1 and NMOS M 3 and the second stage formed by PMOS M 2 and NMOS M 4 . The level converter circuit of this embodiment differs from that of Embodiment 1, in that a gate electrode of PMOS M 1 of the first stage is connected to a drain electrode (i.e., the output terminal VOUT) of PMOS M 2 of the second stage. In the level converter circuit of this embodiment, when the input signal φ 6 from the input terminal VIN is at the H level, NMOS M 3 is ON, PMOS M 1 is OFF, NMOS M 4 is OFF, PMOS M 2 is ON, and therefore the output terminal VOUT outputs the high voltage VDD. Next, when the input signal φ 6 is at the L level, NMOS M 3 is OFF, PMOS M 1 is ON, NMOS M 4 is ON, PMOS M 2 is OFF, and therefore the output terminal VOUT outputs the input signal φ 6 which is the low voltage. In this way, in the level converter circuit of this embodiment, the level-converted output signal φ 8 is in the same phase with the input signal φ 6 as in the case of Embodiment 1. The level converter circuit of this embodiment also provides the advantages similar to those provided by the level converter circuit of Embodiment 1. In the level converter circuit of this embodiment, as shown in FIG. 9 , both NMOS M 3 and PMOS M 1 are not ON at the same time, both NMOS M 4 and PMOS M 2 are not ON at the same time, and consequently any currents do not flow except for switching times in the first and second stages and power consumption is reduced. However, the level converter circuit of Embodiment 1 shown in FIG. 1 has an advantage of higher speed operation than this embodiment. The level converter circuit of this embodiment differs from the level converter circuit of FIG. 14 , in that the external signal φ 6 from the external terminal VIN is applied directly to the gate electrode of NMOS M 3 and the source electrode of NMOS M 4 . As described above, threshold voltages VTH of polysilicon MOS transistors vary greatly, and if the supply voltage is low, drain currents ID vary greatly with the variations of the threshold voltages VTH of the MOS transistors. Therefore, if the level converter circuit of FIG. 14 is formed by polysilicon MOS transistors, there has been a problem in that the variations of a delay time (or a phase difference) of the output signal with respect to the input signal and a duration of the H level (or a duration of the L level) become great mainly due to the threshold voltages VTH of the polysilicon MOS transistors forming the CMOS inverter INV 1 . On the other hand, in the level converter circuit of this embodiment, the gate electrode of NMOS M 3 and the source electrode of NMOS M 4 have the external signal φ 6 applied directly from the external terminal VIN, and consequently, a delay time of the output signal and a duration of the H level of the output signal are prevented from varying greatly with the variations of the threshold voltages VTH of the transistors, NMOS M 3 , M 4 and PMOS M 1 , M 2 , forming the level converter circuit. Embodiment 4 FIG. 10 is a circuit diagram of a level converter circuit of Embodiment 4 of the present invention. As shown in FIG. 10 , the level converter circuit of this embodiment also uses a total of four enhancement-mode transistors including two p-channel polysilicon MOS transistors and two n-channel polysilicon MOS transistors, and has the first stage formed by PMOS M 1 and NMOS M 3 and the second stage formed by PMOS M 2 and NMOS M 4 . The level converter circuit of this embodiment differs from that of Embodiment 2, in that a gate electrode of NMOS M 1 of the first stage is connected to a drain electrode (i.e., the output terminal VOUT) of PMOS M 2 of the second stage. In the level converter circuit of this embodiment, when the input signal φ 6 from the input terminal VIN is at the H level, NMOS M 3 is OFF, PMOS M 1 is ON, NMOS M 4 is ON, PMOS M 2 is OFF, and therefore the output terminal VOUT outputs ground potential VSS. Next, when the input signal φ 6 is at the L level, NMOS M 3 is ON, PMOS M 1 is OFF, NMOS M 4 is OFF, PMOS M 2 is ON, and therefore the output terminal VOUT outputs the high voltage VDD. In this way, in the level converter circuit of this embodiment, the level-converted output signal φ 8 is in the phase opposite from the input signal φ 6 , as in the case of Embodiment 2. As in the case of the level converter circuit of Embodiment 3, in the level converter circuit of this embodiment also, currents flow in the circuits of the first and second stages only during switching times, and power consumption is reduced. However, the level converter circuit of Embodiment 1 shown in FIG. 1 has an advantage of higher speed operation than this embodiment. Embodiment 5 FIG. 11 is a block diagram representing a configuration of a display panel of an active-matrix type liquid crystal display module of the analog sampling type using polysilicon MOS transistors in accordance with Embodiment 5 of the present invention. In FIG. 11 , reference character SUB 1 denotes a transparent insulating substrate made of glass having a softening temperature not higher than 800° C. or quartz glass, reference numeral 3 denotes a display area having a plurality of pixels arranged in a matrix fashion and each pixel is provided with a polysilicon thin film transistor (TFT). Each pixel is disposed in an area surrounded by two adjacent drain electrode lines D and two adjacent gate electrode lines G. Each pixel has a thin film transistor TFT, a source electrode of which is connected to a pixel electrode (not shown). A liquid crystal layer is disposed between each pixel electrode and a common electrode (not shown) opposing all the pixel electrodes, and therefore a capacitor CLC formed by the liquid crystal layer is connected between the source electrode of the thin film transistor TFT and the common electrode in an electrical equivalent circuit. An additional capacitance CADD is connected between the source electrode of the thin film transistor TFT and an immediately preceding gate electrode line G. All the gate electrodes of thin film transistors TFT in the same row among the thin film transistors TFT arranged in a matrix fashion are connected to one of the gate electrode lines G, and each of the gate electrode lines G is connected to vertical scanning circuits 5 disposed on opposite sides of the display area 3 . All the drain electrodes of thin film transistors TFT in the same column among the thin film transistors TFT arranged in the matrix fashion are connected to one of the drain electrode lines D, and each of the drain electrode lines D is connected to a horizontal scanning circuit 4 disposed below the display area 3 . Each of the drain electrode lines D is also connected to a precharge circuit 6 disposed above the display area 3 . Voltage levels of control signals input via control signal input terminals 9 , 10 are level-shifted by level converter circuits 7 in accordance with one of the above embodiments, and are supplied to the horizontal scanning circuit 4 , the vertical scanning circuit 5 and the precharge circuit 6 . In this embodiment, the polysilicon MOS transistors forming the level converter circuits 7 are fabricated on the transparent insulating substrate SUB 1 simultaneously with the thin film transistors TFT of the pixels. In this embodiment, the liquid crystal display panel has incorporated therein the level converter circuits for converting signals (generally 0 to 5 V, 0 to 3.5 V or 0 to 3 V) input from an external circuit into signals of amplitudes (generally high voltages) sufficient to drive the liquid crystal display panel and the circuits formed by polysilicon MOS transistors. Therefore, the present embodiment makes it possible to drive the liquid crystal display panel with output signals from standard logic ICs. In the liquid crystal display module using polysilicon MOS transistors, of this Embodiment also, the first gate electrode line G 1 , for example, is selected by the vertical scanning circuit 5 during one horizontal scanning period, and during this period the horizontal scanning circuit 4 outputs sampling pulses to drive a sample-and-hold circuit SH (not shown) such that analog video signals supplied from video signal input terminals 8 are supplied to each of the drain electrode lines D. In this embodiment, the analog video signals whose frequencies are divided by 12 are supplied from the video signal input terminals 8 , and therefore with one sampling pulse, analog video signals are supplied to twelve drain electrode lines D, respectively. Further, within a retrace time of one horizontal scanning period, the precharge circuit 6 supplies a precharge voltage input from a precharge voltage input terminal 11 to each of the drain electrode lines D. In this embodiment, one of the level converter circuits of the embodiments of the present invention is used as the level converter circuit 7 , and therefore this circuit reduces variations of phases of the sampling pulses and durations of the H level supplied from the horizontal scanning circuit 4 , even if variations occur in the threshold voltages VTH of the polysilicon MOS transistors forming the level converter circuit. Consequently, this embodiment prevent occurrence of a ghost in an image displayed on the liquid crystal display panel, and improves the quality of the displayed image compared with that obtained by the prior art. The present invention is not limited to the liquid crystal display module of the analog-sampling active-matrix type using polysilicon mos transistors, but is also applicable to a liquid crystal display module of the digital-signal-input active-matrix type using polysilicon MOS transistors shown in FIG. 12 . The liquid crystal display module of the digital-signal-input active-matrix type using polysilicon MOS transistors shown in FIG. 12 is the same as the liquid crystal display module of the analog-sampling active-matrix type using polysilicon MOS transistors shown in FIG. 11 , except that the liquid crystal display module of the digital-signal-input active-matrix type is provided with a D/A converter DAC connected to the video signal input terminals 8 . The D/A converter DAC of the liquid crystal display module of FIG. 12 is also comprised of polysilicon thin film transistors fabricated simultaneously with the thin film transistors TFT forming pixels, and therefore digital video signals can be input directly into the liquid crystal display panel. Further, level converter circuits 7 in accordance with one of the above-described embodiments are provided between the D/A converter DAC and the video signal input terminals 8 , and therefore output signals from standard logic ICs can be input directly to the video signal input terminals 8 . In the level converter circuit 7 formed by polysilicon thin film transistors in accordance with one of the above-described embodiments, delay times vary little with the variations of threshold voltages VTH of the polysilicon MOS transistors, and a portion of data is not inverted in the D/A converter DAC and therefore defective displays do not occur. The inventions made by the present inventors have been explained concretely based upon the above embodiments, but the present inventions are not limited to the above embodiments and it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the present inventions. For example, the active-matrix display panel shown in FIG. 11 can be used for an electroluminescent (EL) display device. The following explains briefly advantages obtained by representative ones of the inventions disclosed in this specification. (1) The level converter circuits of the present invention can reduce the total number of transistors required for the level converter circuit. (2) The level converter circuits of the present invention can reduce influences due to variations of threshold voltages of transistors forming the level converter circuit. (3) The liquid crystal display device of the present invention can improve the quality of images displayed on its display panel.

A level converter circuit includes an input terminal adapted to be supplied with a signal swinging from a first voltage to a second voltage lower than the first voltage; a first transistor having a gate electrode connected to the input terminal, and a source electrode connected to ground potential; a second transistor having a gate electrode connected to a drain electrode of the first transistor, a source electrode connected to a supply voltage, and a drain electrode connected to an output terminal; a load circuit connected between the gate electrode of the second transistor and the supply voltage; a third transistor having a source electrode connected to the input terminal, a drain electrode connected to the output terminal, and a gate electrode supplied with a DC voltage higher than the second voltage and lower than the first voltage. The level converter circuit outputs a third voltage higher than the second voltage when the input terminal is supplied with the first voltage, and the level converter circuit outputs the second voltage when the input terminal is supplied with the second voltage.

FIELD OF THE INVENTION [0001] The present invention concerns a system and method for transferring electronic money. More particularly, it relates to improving the checking method used to validate the transfer at a central server. Furthermore the proposed solution improves the traceability of the operations. It is also proposed a data record to implement efficiently the electronic money. BACKGROUND OF THE INVENTION [0002] The electronic money is used within a global system as, for instance, the global system described in the patent application published under reference WO 2012/120011 A1 by the applicant. This system is named after inventor Roberto Giori the Global Standard for Money Technology (GSMT). In such a system, the electronic money is represented by a unique identification named IEDB standing for Identification of an Electronic/Digital Banknote. This IEDB is included in a digital data named RIEDB standing for reference of IEDB. [0003] This electronic money is carried out by its owner in a digital wallet typically implemented as an application in a portable electronic device such as a mobile phone. The system is supervised and controlled by a centralized entity. This entity maintains a database of all the currency managed by the system. It also maintains a database of references of all the users of the system. The users may be registered users owning a reference in the system. In some embodiments the users may be known only by their mobile phone number registered in the course of a transaction. [0004] While the system is registering all the transfers carried out by the users, the reconstitution of all the transactions related to a given electronic banknote is a difficult task. It takes time and it is needed to track all the transfer to find out the ones involving the given banknote. [0005] It is known that the exchanges between mobile phone and systems shall be minimized for cost and real times reasons. The question of the size of exchanged data may be important, for example when the short message service is chosen as a transport bearer. So when this electronic money is carried out by the systems it is important to minimize the length of the data. [0006] The present invention has been devised to address one or more of the foregoing concerns. Its purpose is to make the check of the consistency of the history of transactions related to a particular electronic banknote easier. The proposed solution minimizes the access to the database by embedding the history of transaction within the coding of the electronic banknote itself. [0007] According to a first aspect of the invention there is provided a data record representing an electronic banknote comprising an identifier of the electronic banknote; further comprising embedded within the data record the history of the transactions involving said electronic banknote. [0008] In an embodiment, the history of transaction is represented by a field containing the number of transactions and for each transaction a data record representing the transaction. [0009] In an embodiment, the history of transaction is represented by a field containing the length of said data record representing the electronic banknote and for each transaction a data record representing the transaction. [0010] In an embodiment, the data record representing the transaction comprises an identifier of the electronic banknote; an identifier of the emitter in the transaction; an identifier of the recipient in the transaction; the face value of the electronic banknote; the date of the transaction and the time of the transaction. [0011] In an embodiment, the data record representing the transaction further comprises the location of the transaction. [0012] In an embodiment, the data record representing the transaction further comprises a control sum of said data record representing the transaction. [0013] In an embodiment, the data record representing the transaction further comprises a digital signature of said data record representing the transaction by an authority managing the electronic banknote. [0014] In an embodiment, the data record representing the transaction comprises a reference of a data record representing the transaction within a database. [0015] According to another aspect of the invention there is provided a method for handling an electronic banknote transaction between an emitter and a recipient, comprising by a server a step of receiving a request from the emitter including the identifier of the emitter, the identifier of the receiver and a data record according to the invention representing the electronic banknote to be transferred; a step of validating the data record representing the electronic banknote; a step of generating the outstanding transaction; a step of integrating the outstanding transaction in an updated data record representing the electronic banknote; a step of sending a request to the recipient for validation including the updated data record representing the electronic banknote; a step of receiving an acknowledgment of the transaction from the recipient and a step of validating the transaction. [0016] In an embodiment, the step of validating the data record comprises a step of validating the emitter identifier; a step of validating the integrity and coherency of the history of transaction and a step of validating the recipient identifier. [0017] In an embodiment, the method further comprises a step of creating a user identifier in the server for the recipient when the recipient is not already known. [0018] According to another aspect of the invention there is provided a method for handling an electronic banknote transaction between an emitter and a recipient, characterized in that it comprises by a mobile device of the emitter a step of generating a request including the identifier of the emitter, the identifier of the receiver and a data record according to the invention representing the electronic banknote to be transferred; a step of sending said request to the server; a step of receiving an acknowledgment from the server and a step of updating the virtual wallet of the emitter by removing the transferred electronic banknote. [0019] In an embodiment, the method further comprises a step of sending to the mobile device of the recipient a request for the identifier of the recipient and a step of receiving from the mobile device of the recipient the requested identifier. [0020] According to another aspect of the invention there is provided a method for handling an electronic banknote transaction between an emitter and a recipient, comprising by a mobile device of the recipient a step of receiving a validation request including the identifier of the emitter and a data record according to the invention representing the electronic banknote to be transferred; a step of validating said validation request; a step of sending an acknowledgment to the server and a step of updating the virtual wallet of the recipient by adding the transferred electronic banknote. [0021] In an embodiment, the method further comprises a step of receiving from the mobile device of the emitter a request for the identifier of the recipient and a step of sending to the mobile device of the emitter the requested identifier. [0022] According to another aspect of the invention there is provided a server device for handling an electronic banknote transaction between an emitter and a recipient, comprising means for receiving a request from the emitter including the identifier of the emitter, the identifier of the receiver and a data record according to the invention representing the electronic banknote to be transferred; means for validating the data record representing the electronic banknote; means for generating the outstanding transaction; means for integrating the outstanding transaction in an updated data record representing the electronic banknote; means for sending a request to the recipient for validation including the updated data record representing the electronic banknote; means for receiving an acknowledgment of the transaction from the recipient and means for validating the transaction. [0023] According to another aspect of the invention there is provided a mobile device for handling an electronic banknote transaction between an emitter and a recipient, comprising means for generating a request including the identifier of the emitter, the identifier of the receiver and a data record according to the invention representing the electronic banknote to be transferred; means for sending said request to the server; means for receiving an acknowledgment from the server and means for updating the virtual wallet of the emitter by removing the transferred electronic banknote. [0024] According to another aspect of the invention there is provided a mobile device for handling an electronic banknote transaction between an emitter and a recipient, comprising means for receiving a validation request including the identifier of the emitter and a data record according to the invention representing the electronic banknote to be transferred; means for validating said validation request; means for sending an acknowledgment to the server and means for updating the virtual wallet of the recipient by adding the transferred electronic banknote. [0025] According to another aspect of the invention there is provided a computer program product for a programmable apparatus, the computer program product comprising a sequence of instructions for implementing a method according to the invention, when loaded into and executed by the programmable apparatus. [0026] According to another aspect of the invention there is provided a computer-readable storage medium storing instructions of a computer program for implementing a method according to the invention. [0027] At least parts of the methods according to the invention may be computer implemented. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit”, “module” or “system”. Furthermore, the present invention may take the form of a computer program product embodied in any tangible medium of expression having computer usable program code embodied in the medium. [0028] Since the present invention can be implemented in software, the present invention can be embodied as computer readable code for provision to a programmable apparatus on any suitable carrier medium. A tangible carrier medium may comprise a storage medium such as a floppy disk, a CD-ROM, a hard disk drive, a magnetic tape device or a solid state memory device and the like. A transient carrier medium may include a signal such as an electrical signal, an electronic signal, an optical signal, an acoustic signal, a magnetic signal or an electromagnetic signal, e.g. a microwave or RF signal. BRIEF DESCRIPTION OF THE DRAWINGS [0029] Embodiments of the invention will now be described, by way of example only, and with reference to the following drawings in which: [0030] FIG. 1 illustrates the general architecture of the elements in the system involved in an electronic money transfer; [0031] FIG. 2 illustrates the structure of a record representing an electronic banknote according to an embodiment of the invention; [0032] FIG. 3 illustrates the structure of a record representing a transaction according to an embodiment of the invention; [0033] FIG. 4 illustrates the data exchanges occurring in an electronic money transfer according to an embodiment of the invention; [0034] FIG. 5 illustrates the schematic block diagram of a computing device for implementation of one or more embodiments of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0035] FIG. 1 illustrates the general architecture of the elements in the system involved in an electronic money transfer. The system comprises a central server 1 . 1 . This server may be physically implemented with a plurality of physical servers that may or not be located in a single place. Logically, it is constituted by a database that stores and handles different data stores. A first store registers all the electronic banknotes managed by the system. A second store registers the users of the system. These users may be registered users with a unique identity in the system. In some embodiment of the invention, some users may only be known by their phone number. Actually, this allows the system to be largely used by people without needing to create an account. The formalities to get a mobile phone subscription will replace a regular registration in the system. [0036] A front end 1 . 2 is implementing the different functionalities made available to the users. It gathers the registration of a unique identity of users, the management of this unique identity and the management of the transfer of electronic money involved during a transaction between two users. [0037] A first user owns a first mobile device 1 . 4 holding a virtual wallet 1 . 5 . Similarly, a second user owns a second mobile device 1 . 6 handling a second virtual wallet 1 . 7 . It should be understood that these mobile device may be of any kind as long as they got a user interface to interact with the user, memory storage to store the data representing the virtual wallet and communication means to communicate, references 1 . 8 and 1 . 9 , with the front end 1 . 2 . These communication means are typically using the data communication abilities of the device used for the connection to a data network as Internet. Advantageously, but not necessarily they may also include communication means to communicate directly, reference 1 . 10 , with each other. These direct means of communication may use wireless communication as Bluetooth, WiFi, NFC (standing for Near Field Communication) or others. All these technologies allow establishing a direct communication between two devices in the vicinity of each other and exchanging some data. Typically, the mobile device is a mobile phone, preferably of the smartphone category. [0038] A typical electronic money transfer involves the following operations. Assuming the first user is the emitter, a request for the transfer is submitted from the virtual wallet 1 . 5 to the front end 1 . 2 . This request includes the identity in the system of the emitter. This identity may be constituted by the GSMT unique identifier of the user or by its phone number depending on the embodiment of the invention. The request also includes the identifier of the electronic banknote to be transferred and the identity of the recipient. This identity may be entered in the mobile device 1 . 4 by the emitter or advantageously it may be communicated by the second mobile device 1 . 6 using direct communication means 1 . 10 . Advantageously it also includes the face value of the banknote to be transferred, the time of the transaction request and the location of the emitter at that time. [0039] When received by the frontend server 1 . 2 , the request is checked to determine its validity. Typically, the identity of the emitter is checked with its right to carry out such a transfer. The identity of the recipient is also checked. It is also checked to whether the electronic banknote is registered to actually belong to the emitter. The procedure may include other checks not described here. Next, if all these checks succeed, the frontend 1 . 2 send a request for approval of the transfer to the recipient, namely the second user. This request is sent to the second mobile device using the communication means 1 . 9 . The second user has to approve the transaction. An acknowledgment is then sent from the second mobile device to the frontend 1 . 2 . The frontend validates the transaction and acknowledges it to both users. The electronic money is no longer available in the virtual wallet of the first user while being present in the virtual wallet of the second user. At the server level, the electronic banknote is registered as belonging to the second user. [0040] As a regular paper banknote, the electronic banknote passes from hand to hand as described. To improve the safety of the system and for traceability reason, it is desirable to be able to check the consistency of the history of transaction of a given electronic banknote at the moment of a transaction. This may be done at the server level but it implies some heavy requests in the database to build the history of all the transactions involving a given electronic banknote. Considering the global system contemplated by the invention, carrying out such history check by digging the global database while insuring real time operation of electronic money transfer is very difficult. [0041] The gist of the invention is to embed the history of the transactions involving an electronic banknote within the electronic representation of the banknote itself. An example of detailed embodiment of the invention will now be described in a non-limitative way. [0042] FIG. 2 illustrates the structure of a record representing an electronic banknote according to an embodiment of the invention. The first field 2 . 1 is the length of the data record in byte. Alternatively, this field may contain the length of the data record and the number of transactions stored within. The second field 2 . 2 is the IEDB itself, meaning the identifier of the electronic banknote. Advantageously, the third field 2 . 3 is the face value of the electronic banknote. Next, the data record includes the fields registering the transactions from field 2 . 4 to field 2 . 5 which number is variable. The structure of the transaction field will be detailed below in relation with FIG. 3 . Advantageously, a last field 2 . 6 is there to insure the consistency of the record. This may be a checksum as, for instance, a CRC (Cyclic Redundancy Check). Preferably this field consists in a digital signature of the record by the server using asynchronous cryptography signature algorithm. Accordingly the record may be checked for its authenticity and its integrity. [0043] FIG. 3 illustrates the structure of a record representing a transaction according to an embodiment of the invention. According to this embodiment, the first field 3 . 1 of the record is the identifier of the banknote, namely the IEDB. The second field 3 . 2 of the record is face value of the banknote. The field 3 . 3 is the emitter identifier. This identifier may be the GSMT user identifier of the emitter or alternatively his phone number. Next, the field 3 . 4 of the record is the identifier of the recipient of the transfer. Advantageously, the record may include the date 3 . 5 of the transaction with the time 3 . 6 . It may also include the location 3 . 7 . The location may be obtained automatically by virtue of geolocation means included in the mobile device. Today, most of the smartphone on the market include some geolocation means based on the Global Positioning System or GPS. These geolocation means may also be based on GSM base station triangulation or databases containing the location of WiFi access points. Advantageously, a last field 3 . 8 is there to insure the consistency of the record. [0044] This may be a checksum as, for instance, a CRC (Cyclic Redundancy Check). Preferably this field consists in a digital signature of the record by the server using asynchronous cryptography signature algorithm. Accordingly the record may be checked for its authenticity and its integrity. [0045] FIG. 4 illustrates the data exchanges occurring in an electronic money transfer according to an embodiment of the invention. The main steps involved in a method to carry out an electronic banknote transfer will now be described. The money transfer involves an emitter who is the owner of the electronic banknote and a recipient who is the recipient of the transfer. The server represents the authority managing the electronic money. Both the emitter and the recipient should have a virtual wallet typically operated by a mobile device such as a smartphone. The electronic banknote subject of the transfer belongs initially to the emitter and is managed in his virtual wallet on his mobile device. The emitter as an owner of electronic money is known from the authority managing this electronic money. He owns a unique identity on the server and is identified by a so called GSMT identifier. In some embodiment, this identifier may be his mobile phone number. Typically, the recipient is also known by the authority and also owns a unique identity on the server. In some embodiments, the recipient may be new to the authority. In the latter case, a unique identity will be created on the server in the process of the transfer. This unique identity will then be typically linked to the mobile phone number of the recipient. This unique identity may be automatically created for example based on the mobile phone subscription of the recipient using his phone number. [0046] In a first step, the emitter needs to know about the recipient identifier, this identifier being a GSMT identifier or the phone number. This identifier may be communicated by the recipient to the emitter and entered in the virtual wallet by the latter. Advantageously, the emitter and the recipient establish a direct connection between their devices. This direct connection may be established based on Bluetooth, WiFi or NFC technologies. It may also be established over Internet using the data capabilities of the smartphones. Once the connection is established, the emitter virtual wallet sends a request 4 . 1 to the receiver virtual wallet to request the recipient identifier. The recipient's virtual wallet replies to this request with the message 4 . 2 containing the requested identifier. [0047] During step 4 . 3 , the virtual wallet of the emitter generates a request 4 . 4 to be sent to the server of the authority for the transfer. Advantageously this request includes the identifier of the emitter, the identifier of the receiver and the data record representing the electronic banknote to be transferred. This data record is typically the data record described in relation to FIG. 2 . [0048] During step 4 . 5 , the server is first making some checks on the received request to validate the request. A first check is made on the identity of the emitter. For instance, it is verified if this user is known and is not subject to any restriction. The receiver is also checked for the same. In some embodiments, if the user is not already registered in the system, his unique identity is created at this moment. Next the data record representing the electronic banknote is validated. By virtue of the history of transactions embedded in the data record representing the electronic banknote, it is possible to check the coherency of the transaction chain. Therefore it is possible to check that the current owner is coherent with all the past transaction related to this banknote. This verification may be carried out without needing to access the database. This is a great advantage considering that the system is supposed to handle a great amount of users and transaction and that the response of the server needs to be made as fast as possible to allow a real time. By embedding the history of transactions right into the data record representing the electronic banknote, the desirable verifications may be conducted easily and rapidly saving the need to access in real time the huge central database to consolidate the chain of transactions in order to determine if the emitter is the actual owner of the banknote. Next, the record of the outstanding transaction is generated and integrated in the data record representing the electronic banknote. Its storage stands by waiting to the validation by the recipient. [0049] Next, a request for validation 4 . 6 is sent to the recipient. Advantageously, this request includes the identifier of the emitter and the data record representing the electronic banknote including the outstanding transaction. During step 4 . 7 , the transaction is presented to the recipient for validation. Once the transaction has been validated by the recipient an acknowledgment 4 . 8 is sent back to the server. According to a particular embodiment of the invention, the recipient's virtual wallet may be adapted to carry out a validity check on the data record representing the electronic banknote. By virtue of the presence of the embedded history of transactions within the data record, a check of the transaction chain may be made by the wallet of the recipient. This allows the recipient to validate on his own the electronic money which is proposed to him without the need to access the central server. [0050] During step 4 . 9 , the server checks the received data record representing the electronic banknote and checks it for coherency and validity. The outstanding transaction is then validated and stored in the database. Acknowledgments 4 . 10 and 4 . 11 are sent to both the emitter and the receiver to validate the transaction. The virtual wallets of the emitter and the recipient are updated accordingly in step 4 . 12 respectively 4 . 13 . The transferred banknote is removed from the virtual wallet of the emitter and added to the virtual wallet of the recipient. [0051] As an electronic banknote may be subject to numerous transactions, the data record representing it may reach an important size. Advantageously, in an alternative embodiment, the complete data record representing the transaction in the data record representing the banknote is replaced by a reference of this data record stored in the server. This reference must allow the server to retrieve unequivocally the data record representing the transaction. It may be constituted by a unique identifier of the data record in the database. It may also be constituted by a hash function of the data record. It may also be constituted by a date referenced at absolute date with enough precision to give a reference. In general the date is coded on 64 bits (8 bytes). By storing only the references of the transaction embedded in the data record representing the electronic banknote this data record is kept of reasonable size. [0052] It is to be noted that, in some embodiment of the system, the history of transactions is used to allow a postiori checks on the electronic banknote. The aim is to prevent a person to use the identity of a banknote to submit illegal transactions. Without the history of transaction, it would be possible to submit a request for a transaction using the banknote id which is not coherent with the global chain of transaction registered for this banknote. An a postiori check may consist in checking that the references of the transactions registered within the electronic banknote corresponds to the ones registered in the server. To do so, it is sufficient to compute the reference of each transaction involved in the history of transaction and check if this reference match the reference stored in the embedded history of transaction. Therefore, it is not needed that the reference stored in the embedded history of transaction represents the transaction unequivocally. A regular hash function may be used to this goal. By doing so, an old version of the electronic banknote with its embedded history of transaction that might have been stolen may not be used to generate a further illegal transaction. [0053] The database storing the transaction may be used for statistical reason and history of transaction may be carried on based on the identity of the banknote, the date of the transaction, the identity of the user and the location. It may be used to detect malicious usages based on the frequency of transaction and locations. Malicious users may be identified. [0054] However for some exchanges, it might be advantageous to further reduce the size of the exchanged data on the network. Typically, if the short messages service (SMS) is used as a transport bearer. The typical length of a SMS message is 160 bytes. In a context where a reasonable number of references of transactions must be kept in the data record and that the absolute date the invention is used as a reference, it is possible to code date by coding a difference with a reference date instead of coding the absolute date. The difference may be coded using only 32 bits where the absolute date is typically coded using 64 bits. The reference date may be, for example 1/01/2012 00:00:00 or the date of the first transaction of the given banknote. [0055] Advantageously, to keep a maximum of number of transaction, it is possible to reduce the size of the references of previous transactions. For example, the original format of the date might be kept while reducing by truncation some of the time references. This process may be adapted according to number of existing references in the data record representing the banknote. [0056] In the case where only transaction references are embedded in the electronic banknote, the check of the complete transaction chain to validate the owner of the banknote may be carried out in a posteriori check process to avoid accessing the database during the real time validation of the outstanding transaction. A check of the control sum, or better the electronic signature, of the data record associated with the a posteriori check of the complete transaction chain may be considered as sufficient to ensure a good level of security on the transfer. [0057] According to the invention, a complete traceability of the transactions related to a given banknote is provided. This traceability may be checked without the need of digging a central data base. The traceability information is linked to the electronic banknote and follows it being embedded within the electronic representation of this banknote. [0058] FIG. 5 is a schematic block diagram of a computing device 500 for implementation of one or more embodiments of the invention, typically the device handling the virtual wallet. The computing device 500 may be a device such as a micro-computer, a workstation or a light portable device. The computing device 500 comprises a communication bus connected to: a central processing unit 501 , such as a microprocessor, denoted CPU; a random access memory 502 , denoted RAM, for storing the executable code of the method of embodiments of the invention as well as the registers adapted to record variables and parameters necessary for implementing the method for encoding or decoding at least part of an image according to embodiments of the invention, the memory capacity thereof can be expanded by an optional RAM connected to an expansion port for example; a read only memory 503 , denoted ROM, for storing computer programs for implementing embodiments of the invention; a network interface 504 is typically connected to a communication network over which digital data to be processed are transmitted or received. The network interface 504 can be a single network interface, or composed of a set of different network interfaces (for instance wired and wireless interfaces, or different kinds of wired or wireless interfaces). Data packets are written to the network interface for transmission or are read from the network interface for reception under the control of the software application running in the CPU 501 ; a user interface 505 may be used for receiving inputs from a user or to display information to a user; a hard disk 506 denoted HD may be provided as a mass storage device, alternatively, the mass storage may be constituted of flash memory; an I/O module 507 may be used for receiving/sending data from/to external devices such as a video source or display. [0066] The executable code may be stored either in read only memory 503 , on the hard disk 506 or on a removable digital medium such as for example a disk. According to a variant, the executable code of the programs can be received by means of a communication network, via the network interface 504 , in order to be stored in one of the storage means of the communication device 500 , such as the hard disk 506 , before being executed. [0067] The central processing unit 501 is adapted to control and direct the execution of the instructions or portions of software code of the program or programs according to embodiments of the invention, which instructions are stored in one of the aforementioned storage means. After powering on, the CPU 501 is capable of executing instructions from main RAM memory 502 relating to a software application after those instructions have been loaded from the program ROM 503 or the hard-disc (HD) 506 for example. Such a software application, when executed by the CPU 501 , causes the steps of the flowcharts shown in FIGS. 1 to 4 to be performed. [0068] Any step of the algorithm shown in FIG. 4 may be implemented in software by execution of a set of instructions or program by a programmable computing machine, such as a PC (“Personal Computer”), a DSP (“Digital Signal Processor”) or a microcontroller; or else implemented in hardware by a machine or a dedicated component, such as an FPGA (“Field-Programmable Gate Array”) or an ASIC (“Application-Specific Integrated Circuit”). [0069] Although the present invention has been described hereinabove with reference to specific embodiments, the present invention is not limited to the specific embodiments, and modifications will be apparent to a skilled person in the art which lie within the scope of the present invention. [0070] Many further modifications and variations will suggest themselves to those versed in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only and which are not intended to limit the scope of the invention, that being determined solely by the appended claims. In particular the different features from different embodiments may be interchanged, where appropriate. [0071] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be advantageously used.

The present invention concerns a system and method for transferring electronic money. More particularly, it relates to improving the checking method used to validate the transfer at a central server. Furthermore the proposed solution improves the traceability of the operations. It is also proposed a data record to implement efficiently the electronic money. Its purpose is to make the check of the consistency of the history of transactions related to a particular electronic banknote easier. The proposed solution minimizes the access to the database by embedding the history of transaction within the coding of the electronic banknote itself.

BACKGROUND OF THE INVENTION 1. Field of Invention This invention relates to solar heating systems for interior portions of structures and in particular discloses a solar heating system employing a thermal siphon effect. By passive system, it is meant a system devoid of externally powered fluid pumping means, such as electrically powered pumps for circulating fluid. 2. Description of the Prior Art Solid wall solar heating and storing devices are well-known. The classic Trahmbe Wall is well-known. The Trahmbe Wall is typically a solid structure of large mass which absorbs solar radiation on one face during daylight storing heat in the mass, and during darkness dissipating the heat through the opposing face into an enclosure. Also well-known to the art is the thermal siphon comprising a boiler coupled in a closed circuit to a radiator. The thermal siphon is a passive system, that is, it is a system which does not employ an externally powered pump to circulate the fluid. The only energy input is through the heat supplied to the fluid in the boiler. A need exists to provide a passive heating system for receiving solar radiation, storing heat so generated, and supplying the heat for space heating. In paticular, there is a need for a passive system which can be modularized and easily installed in a building. SUMMARY OF THE INVENTION According to the invention, a space heater and a method for space heating are disclosed which employ solar radiation as a thermal energy source to passively heat spaces within a structure which are substantially remote from direct solar radiation. A device according to the invention comprises a sealed circuit path for a fluid, such as a liquid, which is employed to communicate thermal energy from a radiation source or target to a thermal dissipation sink or radiating surface. The fluid, which may be water or a eutectic liquid such as propylene glycol, is heated at the radiation target and conveyed by a thermal siphon effect, that is by fluid convection, around the closed and sealed circuit. A vertical differential is provided within the closed circuit, and a thermal differential is developed between the radiation source and the dissipation sink which is sufficient to develop power to effect the fluid circulation. In particular, the device is embodied in a modular wall segment having a radiation absorbing surface on only one face, and wherein the other faces are thermal dissipators. Essential to the operation of the invention is thermal insulation between the segments of the closed circuit. The thermal insulation may be a partition centrally located within the wall, one side of the partition having risers in thermal contact with the radiation absorbing face and the other side of the partition having downcomer pipes in thermal contact with a thermal dissipating face. The risers and downcomers are connected in a closed circuit through a thermally insulated reservoir for storing the fluid. The reservoir is preferably located within the wall module. To optimize thermal storage, the reservoir may be located near the top of the module at the output of the risers from the radiation absorbing surface. The reservoir may also be located in or along the base of the module to lower its center of gravity. The module is particularly suited for installation as a wall module centrally within a structure without disturbing the location or orientation of the outside walls. According to the invention, a structure is provided with a clerestory having a window permitting solar radiation to impinge upon the radiation abosrber of the device, where the device is centrally located within the structure. The structure may be a two-story building with spaces or rooms to be heated abutting the device. The device may extend the height of two stories. Since the device is modular, and since it is located centrally within the structure, it can radiate heat from opposing faces to easily heat adjacent spaces. It is an object of the invention to provide a solar radiation-excited thermal-siphon space heating device incorporated within a wall. It is a further object of the invention to provide a solar heating device which can be centrally located within a structure. It is a still further object of the invention to provide a modular solar heating device which can be centrally located within a building having random orientation or without a south-facing outer wall exposed to solar radiation. It is a still further object of the invention to provide a modular passive solar heating system, that is a solar heating system without the use of externally powered fluid pumping means. These and other objects of the invention will be best understood by reference to the following detailed description taken together with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a side elevational view of a structure in partial schematic illustrating the functional elements of the invention. FIG. 1B is a top plan view of FIG. 1A. FIGS. 1A and 1B are referred to collectively as FIG. 1. FIG. 2 is a side cross-sectional view of a wall module according to the invention. FIG. 3 is a front elevational view illustrating various wall modules which are constructed according to the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIGS. 1A and 1B depict a structure 10 according to the invention comprising a plurality of rooms 12, 14, 16 and 18, and a clerestory 20 with a south-facing window 22. Adjustable louvers 24 may be provided to regulate the radiation through the window 22. The angle of the clerestory 20 roof is selected to provide maximum radiation through the window 22 during the winter while at least partially shading the building interior during the summer months. At a latitude for San Francisco, 38° N. Lat., the angle of the roof for midday sun on the first day of winter is about 23°. The midday summer sun is considerably higher, namely about 76° on the first day of summer. Centrally located and disposed on an east-west axis with a south-facing vertical face aligned with the midday sun is a space heating device 26 according to the invention. The outer walls of the structure 10 may have a random orientation to the midday sun, as is depicted in FIG. 1B. The device 26 comprises first and second rigid outer membranes 28 and 30 which serve as wall faces, a central insulating core 32, and a fluid path surrounding the core 32. The fluid path may comprise pipes or thin sheet-like chambers as hereinafter described. In addition, there is a target area for the solar radiation, and typically near the top of the first membrane 28. Turning to FIG. 2, there is shown in greater detail the device 26 constructed as a wall module. The circuit path comprises riser pipes 34 and downcomer pipes 36 disposed on opposing sides of the core 32. The riser pipes 34 and downcomer pipes 36 are provided with means 38 and 40 for coupling to a storage unit, such as a reservoir 42 integrally contained within the device 26. The coupling means 38 and 40 may be suitable pipe couplings adapted for sealed connection with the reservoir inlets and outlets respectively. The reservoir 42 is provided with a thermal insulative blanket 44 to insulate against thermal dissipation. The reservoir may be located within the device 26 adjacent its bottom margin. Where the reservoir 42 is located adjacent the bottom margin, the output coupling means 40 of the downcomer pipe 36 are preferably connected adjacent the bottom margin of the reservoir 42, and the input coupling means 38 of the riser pipes 34 are preferably coupled to the reservoir 42 higher than the outlet means 38. The wall membranes 28 and 30 are preferably thermally conductive material such as aluminum or similar rigid sheet material. The riser pipes 34 are in intimate thermal contact with the first membrane 28, and the downcomer pipes 36 are in intimate thermal contact with the second membrane 30 on the opposing face of the device 26. To effect the intimate thermal contact, a thermally conductive grease may be interposed between the pipes and the membranes 38 and 40. The first membrane 28 is provided with a radiation absorption means 46 in the radiation target area. The radiation absorbing means 46 may be a coating of flat black paint on the surface of the membrane 28 which serves as a black body absorber to absorb solar radiation and to convert it to thermal energy which may be conveyed through the conductive membrane 28 to the riser pipe 34. The riser pipes 34 may be connected to a header 48 horizontally disposed across the top of device 26. The header 48 is also coupled to the downcomer pipes 36 along the opposite side of the core 32. The remaining surfaces of the membranes 28 and 30 may be painted or coated with a material which enhances radiation. This includes any light-colored paint such as white, beige, tan, and olive. Exposed embossed metallic surfaces are superior radiators but are becoming unacceptable as an interior wall covering. The method of the invention can now be explained. Referring to FIGS. 1 and 2, the fluid circuit is filled with a fluid, such as a liquid including water or a eutectic liquid such as propylene glycol. Radiation from the sun is directed to impinge upon the radiation absorbing means 46, causing the membrane 28 thereunder to heat and to conduct the thermal energy to the riser pipes 34. The thermal energy so conducted causes the fluid in the abutting riser pipes 34 to heat, convectively rising toward the apex of the circuit in header 48. A positive thermal differential between the fluid in downcomer pipes 36 and adjacent space abutting the radiation surfaces of membranes 28 and 30 causes heat to be dissipated into that space. The space is heated by conduction, convection and also by radiation. The heat so dissipated causes a thermal differential across the insulative core 32 to create fluid convection around the circuit path and through the reservoir 42. The thermal energy is dissipated in all areas of the circuit path where there is a positive thermal differential between the fluid and the adjacent air space through the membranes 28 and 30. The zone comprising the heat absorbing means 46 and riser pipes 34 adjacent the heat absorbing means may be termed the first or energy receiving zone. All other zones of the circuit providing a path for thermal dissipation comprise a second or thermal dissipating zone. Referring again to FIGS. 1 and 2, the header 48 may serve as a heat exchanger. In particular, a U-tube 50 may be provided within the header 48 to provide a path 52, 54 to preheat water supplied to a hot water heater 56. Additionally, the device 26 may be provided with a backup system for supplying heat to the fluid in the device 26 during periods of minimal radiation input. The backup system may comprise a boiler 58 (FIG. 1) coupled through an inlet line 60 to inlet means 62 (FIG. 2) at the top of the device 26 and having a return line 64 (FIG. 1) coupled to outlet means 66 near the bottom of the fluid circuit. A one-way valve 68 (FIG. 1) in the inlet line 60 may be provided to prevent backflow of fluid into the boiler which might prevent proper circulation of the solar heated fluid in the device 26. Alternatively, the boiler 58 and its circuit could be decoupled by one or more stop valves from the device 26. The boiler 58 also operates on a thermal siphon principle, that is, devoid of any external fluid pumping means in the circuit. Referring again to FIG. 1, there are shown a plurality of blinds 70, 72, and 74. These blinds may be disposed in front of the device 26 and across its entire width to modulate the amount of thermal dissipation from the dissipating surfaces. In this manner, the heat radiated to each of the rooms 14, 16 is inexpensively moderated. The room 12 adjacent the radiation absorbing means 46 is generally designated as a nighttime sleeping area. During the daytime it receives direct radiation from the clerestory, and at night it receives heat through dissipation as do the other rooms 14, 16 and 18 although to a lesser degree due to the presence of the absorbing means 46 on the adjacent wall portion of the device 26. The fluid reservoir 42 may also be located adjacent the upper portion of the wall module, and in fact the header 48 shown in FIG. 2 may also serve as a heat storage reservoir to the extent it is thermally insulated. In the case the reservoir 42 is disposed at the top of the device 26, the inlet should be provided above the outlet, as is shown in FIG. 2. Referring now to FIG. 3, a number of alternative embodiments of the invention are shown. Device 26 as described hereinabove is shown to the left of FIG. 3 and at the bottom center of FIG. 3. The wall module is approximately 36 inches wide and may extend two stories (as in the left side) or one story (as shown in the lower center side). The riser and downcomer pipes 34 and 36 may be one-half inch metal pipes spaced approximately four inches apart along the inner surfaces of the membranes 28 and 30. The reservoir 42 is disposed at the bottom of the module and is surrounded by insulative blanket 44. The radiation absorption means 46 is provided on the outer surface of the membrane 28 adjacent the upper margin so that it is in full confrontation with radiation through clerestory 20 (FIG. 1). Various adaptations may be made. For example, a provision may be made within a module 126 to receive a window 70, as shown to the upper center of FIG. 3. For this purpose, auxiliary risers 134 and downcomers 136 are required to bypass the space for the window 70 and a first intermediate header 148 and second intermediate header 149 are provided to collect fluid for the bypass. Space may also be provided for a door 72 between modules by providing a header bridge 74 across the top of the door, as shown in the upper center of FIG. 3. Quick connect fluid couplings may be provied between reservoirs 42 and downcomer pipes 36 with sealed couplings 76. In addition, quick connect sealed fluid couplings 77, 79 may be provided between adjacent headers 48 and also bridge 74 as well as between adjacent reservoirs 42 of abutting modules. The connectors 77, 79 may be similar to the Ring-Tite quick connect couplings manufactured by Johns-Manville Pipe Division, Stockton, Calif. FIG. 3 in the lower right-hand corner shows a further alternative embodiment. There is depicted a device 226 according to the invention wherein the fluid is stored and conveyed in sheet-like chambers 234 (for rising fluid) and 236 (for falling fluid). The chambers 234, 236 may have corrugated or lattice interior structures to prevent buckling. While metal is preferred for its heat conductive properties and high temperature resistance, still other materials may be employed in the circuit path. For example, UPVC (unplasticized Poly Vinyl Chloride) and some thermosetting plastics having high heat resistance and high resistance to warp at relatively high temperatures (above 250° F.) might be employed as a wall material. The structure and elements of the structure could be extruded to the desired shape to achieve economies in construction of modular units. The fluids best suited for use in the invention, and comprising an element of the invention in particular embodiments, include water, eutectic mixtures such as propylene glycol and water, liquid fluorocarbons, alcohols, glycols, salt waters, lithium chloride and metal which are liquid at the working temperatures, such as mercury. Mercury has the advantage of an extremely high heat capacity. However, its expense probably makes it prohibitive in practical applications of the invention. The invention has now been explained with reference to particular embodiments. Other embodiments will be apparent to those of ordinary skill in the art with reference to this disclosure, including Specification and drawings. It is therefore not intended that the invention be limited except as indicated by the appended claims.

Space heating is disclosed which uses solar radiation as a thermal energy source to passively heat spaces within a structure which are substantially remote from direct solar radiation. A device according to the invention includes a radiation target, a closed and sealed circuit path for a fluid, such as a liquid, which is employed to communicate thermal energy from a radiation source to a thermal dissipation sink and a thermal dissipator, all incorporated as elements of a wall module which is adapted to be placed centrally within a structure which may not have a south-facing outer wall. A clerestory generally above the wall module provides a window for solar radiation to the radiation target. The fluid is conveyed by a thermal siphon effect, that is, by fluid convection, in a closed and sealed circuit. A vertical differential is provided within the closed circuit, and a thermal differential between segments of the circuit develops sufficient power to effect fluid circulation.

This application claims priority from Great Britain Application No.: 9727346.0 filed Dec. 24, 1997 in the name of Northern Telecom Limited. FIELD OF THE INVENTION This invention relates to a radio communications system and in particular relates to a base station arrangement in a fixed wireless access system. FIELD OF THE INVENTION Fixed wireless access systems are currently employed for local telecommunication networks, such as the IONICA system. Known systems comprise an antenna and decoding means which are located at a subscriber's premises, for instance adjacent a telephone. The antenna receives the signal and provides a further signal by wire to a decoding means. Thus subscribers are connected to a telecommunications network by radio link in place of the more traditional method of copper cable. Such fixed wireless access systems will be capable of delivering a wide range of access services from POTS (public operator telephone service), ISDN (integrated services digital network) to broadband data. The radio transceivers at the subscribers premises communicate with a base station, which provides cellular coverage over, for example, a 5 km radius in urban environments. A typical base station will support 500-2000 subscribers. Each base station is connected to a standard PSTN switch via a conventional transmission link/network. When a fixed wireless access telecommunications system is initially deployed, then a base station of a particular capacity will be installed to cover a particular populated area. The capabilities of the base station are designed to be commensurate with the anticipated coverage and capacity requirement. Subscribers' antennas will be mounted outside, for instance, on a chimney, and upon installation will normally be directed towards the nearest (or best signal strength) base station or repeater antenna (any future reference to a base station shall be taken to include a repeater). In order to meet the capacity demand, within an available frequency band allocation, fixed wireless access systems divide a geographic area to be covered into cells. Within each cell is a base station through which the subscribers' stations communicate; the distance between the cells being determined such that co-channel interference is maintained at a tolerable level. When the antenna on the subscriber premises is installed, an optimal direction for the antenna is identified using monitoring equipment. The antenna is then mounted so that it is positioned towards the optimal direction. There are a number of alternative ways of providing access to the public telephone network, besides fixed wireless access systems. One method is to use copper or optical fibre cable. However, this involves digging up streets in order to lay cables past all the homes in the service area which is expensive, time consuming and causes noise, dirt, damage to trees and pavements and disrupts traffic. After the initial high investment the telephone company can then only start to recoup its investment as new subscribers join the system over a period of time. Another alternative is cellular radio such as GSM. This has the advantage that the telephones are mobile. However, the system operator has to provide continuous coverage along motorways, in shopping malls, and so on. The low-height omni directional antenna used in mobile systems gives little discrimination against multipath interference, and its low height makes it more susceptible to noise. Also, when a mobile moves it suffers constantly varying multipath interference which produces varying audio quality. Mobile cellular networks also require expensive backhaul networks which consist of expensive switches and an expensive master control centre which handle the movement of mobiles from one cell to another. Radio systems based on mobile standards with fixed directional antennas are sometimes used to provide access to the public telephone network. The directional antenna discriminates against some of the multipath interference. However, the system still suffers from the disadvantages already mentioned. For example, an expensive backhaul network is required and the speech quality is inferior to a copper wire system. Fixed wireless access systems comprise a base station serving a radio cell of up to 5 km radius (for example). The base station interfaces with the subscriber system via a purpose designed air interface protocol. The base station also interfaces with the public telephone network for example, this interface can be the ITU G.703 2048 kbit/s, 32 timeslot, 30 channel standard known as E1 or the North American 24 timeslot standard known as T1. Typically, each uplink radio channel (i.e. from a subscriber antenna to a base station) is paired with a downlink radio channel (i.e. from, a base station to a subscriber antenna) to produce a duplex radio channel. For voice signals the up and down link channels in a pair normally have the same frequency separation (e.g. 50 MHz between uplink and downlink channels) because this makes the process of channel allocation simple. However, it is possible for the up and down link channels in a pair to have different frequency separations. Often each downlink transmits continuously and it is usual for those downlink bearers used to carry broadcast information to transmit continuously. In the uplink each subscriber antenna typically only transmits a packet of information when necessary. A bearer is a frequency channel and will often have several logical channels, for example, time divided or code divided channels. Base stations are then allocated radio bearers from the total available, for example, 54. As the subscriber population increases the base station capacity can be increased by increasing the number of bearers allocated to it, for example, 3, 6 or 18 bearers. As already mentioned, fixed wireless access systems divide a geographic area to be covered into cells. For initial planning and design purposes these cells are usually represented as hexagons, each cell being served by a base station (in the centre of the hexagon) with which a plurality of subscriber stations within the cell (hexagon) communicate. When detailed cell planning is performed the ideal hexagonal arrangement can start to break down due to site constraints or for radio propagation reasons. The number of subscriber stations which can be supported within each cell is limited by the available number of carrier frequencies and the number of channels per frequency. Base stations are expensive, and require extensive effort in obtaining planning permission for their erection. In some areas, suitable base station sites may not be available. It is preferred in fixed wireless access system design to have as few base stations as possible, whilst supporting as many subscriber stations as possible. This helps to reduce the cost per subscriber in a fixed wireless access system. An on-going problem is to increase the traffic carrying capacity of base stations whilst at the same time keeping interference levels within acceptable bounds. This is referred to as trying to optimise or increase the carrier to interference level or C/I ratio. By increasing the traffic capacity the number of lost or blocked calls is reduced and call quality can be improved. (A lost call is a call attempt that fails). Cells are typically grouped in clusters as shown in FIG. 1. In this example, a cluster of seven cells is shown and for a 6 bearer system, each cell in the cluster may use a different group of 6 frequencies out of the total available (for example, 54). Within each cluster 7×6=42 frequencies are each used once. This leaves 12 channels for in-fill if required. Within the cluster all channels are orthogonal, for example, separated by emitter time and/or frequency, and therefore there will be no co-channel interference within this isolated cluster. FIG. 2 shows how a larger geographical area can be covered by re-using frequencies. In FIG. 2 each frequency is used twice, once in each cluster. Co-channel interference could occur between cells using the same frequencies and needs to be guarded against through cell planning. When the capacity of a cell or cluster is exhausted one possibility is to sectorize each cell. This involves using directional antennas on the base station rather than omnidirectional antennas. The 360° range around the base station is divided up into a number of sectors and bearers are allocated to each sector. In this way more bearers can be added whilst keeping interference down by only using certain frequencies in certain directions or sectors. For example, up to 12 bearers per cell could be added giving a total of 18 bearers per cell, the number of cells in a cluster drops to three, as shown in FIG. 3. This is because all 54 frequencies are used in the cluster and will be re-used in other clusters. Known approaches for seeking to increase system capacity include frequency planning which involves carefully planning re-use patterns and creating sector designs in order to reduce the likelihood of interference. However, this method is complex and difficult and there is still the possibility that unwanted multipath reflections may cause excessive interference. Frequency planning is also expensive and time consuming and slows down the rate of deployment. Some of the difficulties with frequency planning include that it relies on having a good terrain base and a good prediction tool. WO96/13952 describes a method for hexagonal sectored obtaining a one cell re-use pattern in a wireless communications system but does not provide a suitable operational system. OBJECT OF THE INVENTION The present invention seeks to provide a base station arrangement in a fixed wireless access system, which overcomes or at least mitigates one or more of the problems noted above. It is sought to increase the traffic carrying capacity of base stations whilst at the same time keeping interference levels to a minimum. SUMMARY OF THE INVENTION According to the present invention there is provided an antenna arrangement for a fixed wireless access base station comprising at least one pair of directional antenna wherein the pair of antennas have a common phase centre. Ensuring that the antenna have a common phase centre means that any co-frequency same sector interference signals experienced by the first antenna of the pair and which is associated with the sidelobes of the second antenna of the pair will fade in a manner which is correlated with the fading of the main signal associated with the main lobe of the first antenna. Therefore, the ratio between the strength of the main signal and the strength of the interference signal is held substantially constant over the sector. This is advantageous for networks in which there is a tough front to back sidelobe ratio for the base station antenna arrangement. Where both antenna in the pair operate on at least one common frequency channel co-channel interference is more manageable and so both antenna in the pair can operate on a majority of common frequency channels or indeed have all frequencies in common. This can facilitate same cell frequency re-use and thus can increase capacity. The two antenna in each pair are preferably oppositely directed and a plurality of pairs of antenna are arranged spaced apart in a tier about a support so as to provide cell sector coverage. Preferably, the antenna each have a substantially horizontal bore sight. To provide a good C/I ratio it is preferable that each of the antenna pairs operate on at least one frequency channel which is different from those on which the other antenna pairs operate. In order to provide spatial diversity a second tier of antenna substantially the same as the first and which is vertically separated from the first tier is added. Preferably, the antenna pairs in the second tier are located to the opposite side of the support to the equivalent antenna pair of the first tier. Again this provides diversity, but also ensures that the antennas do not physically block each other. To provide coverage in each sector from an antenna in the first tier and in the second tier, each antenna in the second tier is directed with its bore sight in the same direction as the equivalent antenna in the first tier. A further advantage provided by this arrangement is that if there is a soft fail for one antenna group, then the existence of a second independent antenna group will ensure that transceive capabilities of the base station are maintained. In a preferred six sector arrangement three antenna pairs are arranged in each tier and are spaced 120° apart. To increase the capacity of the antenna arrangement according to the present invention different antennas can operate with different polarisations. If the frequency channels on which the antenna arrangement according to the present invention operate are time divided then it is preferred that the time slots for each tier of antenna are synchronised. BRIEF DESCRIPTION OF THE DRAWINGS In order that the present invention is more fully understood and to show how the same may be carried into effect, reference shall now be made, by way of example only, to the figures as shown in the accompanying drawing sheets, wherein: FIG. 1 shows a cluster of seven cells that are represented as hexagons; FIG. 2 shows two clusters of seven cells where each frequency is re-used twice, once in each cluster; FIG. 3a shows a 6 bearer omni deployment with a cluster size of 7, using 42 frequencies out of the total available of 54; FIG. 3b shows the deployment of FIG. 3a after each cell has been sectorized by adding 12 bearers per cell giving a total of 18 bearers and tripling the capacity of each cell. The number of cells per cluster is now 3; FIG. 4 shows a two tier antenna arrangement according to the present invention; FIG. 5 shows a plan view of a first tier of the antenna arrangement of FIG. 4; FIG. 6 shows a plan view of a second tier of the antenna arrangement of FIG. 4; FIG. 7 shows a frequency plan which can be implemented using the antenna arrangement of FIG. 4; FIG. 8 shows schematically two types of downlink interference; and FIG. 9 shows schematically two types of uplink interference. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS There will now be described by way of example the best mode contemplated by the inventors for carrying out the invention. In the following description, numerous specific details are set out in order to provide a complete understanding of the present invention. It will be apparent, however, to those skilled in the art that the present invention may be put into practice with variations of the specific. The first tier T1 of the antenna arrangement shown in FIG. 5 comprises 6 directional antennas (2, 4, 6, 8, 10 and 12). The 6 antennas are arranged in pairs. Each pair is arranged in a back-to-back configuration with a common phase centre and each pair operate in the same group of frequencies, for example frequency group f3 for antennas 10 and 12. A phase centre is the point from which an antenna seems to be radiating. By having a common phase centre the main front facing lobe of one of each pair of antenna (for example the main lobe 14 of antenna 10) has substantially the same phase centre as the rear facing side lobes of the other of each pair of antenna (for example the side lobes 16 of antenna 12). Accordingly, the signals of interest which are associated with the main lobe 14 of antenna 10 and the same sector co-channel interference signals which are associated with the side lobes 16 of antenna 12 follow substantially the same paths. If the signal of interest and the interference signals follow substantially the same path they will encounter substantially the same obstacles and therefore will experience the same level of attenuation. This enables a constant ratio to be maintained between the strength of the signals of interest and interference signals in each directional sector of a cell. Therefore, an interference signal experiencing a low attenuation level along its path through space is unlikely to approach the strength of the main signal because the main signal will also have experienced the same low level of attenuation. The second tier T2 of antennas of FIG. 6 are superimposed on the first tier of antennas T1 described above in relation to FIG. 5. The second tier of antennas is substantially identical to the first tier of antennas, except that each pair of antennas in the second tier has been moved to the opposite side of the mast 26 from the equivalent pair (operating in the same frequency group) in the first tier. This provides spatial diversity between antennas operating in the same sector (for example 2 and 2' etc.). Therefore, if an antenna in a subscriber's unit cannot receive a strong signal from antenna 2 because of high attenuation along the signal path, it should be able to receive a strong signal from antenna 2' because hopefully the signal path to antenna 2' will not have such high attenuation. Referring now to FIG. 7, which shows a cell plan associated with the antenna arrangement of FIGS. 5 and 6, with reference to cell 18, antenna 2 and 2' operate in sector 20, antenna 8 and 8' operate in sector 22, antenna 10 and 10' operate in sector 24, etc. It can be seen from FIG. 5 that y (directed eastwardly) indicates the axis of primary receive antenna 2 coverage which is supplemented, with reference to FIG. 6, by the secondary diversity antenna 2' which provides a diversity receive antenna coverage indicated by y'. Each pair of antennas is mounted with a common phase centre for forward and reverse co-frequency transmissions whereby it is possible to maximise the correlation of fading of same-cell co-channel interference. Referring now to FIG. 4 there is shown in perspective view a first embodiment of an antenna arrangement made in accordance with the invention. The antennas are arranged in groups in two vertically separated tiers, a first tier T1 as shown in FIG. 5 and a second tier T2 as shown in FIG. 6. Each antenna has a main propagation direction perpendicular to an axis from a centre of the arrangement. This centre may be coincident with a support, for example a mast 26, of course the support could comprise a geodetic-pylon like structure or other well known types. One approach to improve the capacity of a network of base stations is to increase frequency re-use in a frequency plan. One approach, would be to use a six or nine sector frequency plan in which each frequency is used in one sector of each and every cell. A sector rotation plan increases the d/r ratio well above 3. This d/r ratio can also be achieved without sector rotation by polarisation re-use. This n=1 frequency plan requires that the subscriber unit antenna has a good sidelobe front to back ratio in order for the C/I ratio to be acceptable. This generally will require a relatively expensive subscriber unit. As there are many more subscriber units as compared to base stations, it would be more cost effective to use a frequency plan in which the base station antenna front to back ratio has to be minimised and which is less demanding on subscriber unit requirements. FIG. 7 shows such a frequency plan which is ideally suited for use with the antenna arrangement according to the present invention. The frequency plan of FIG. 7 is a 6 sector plan suitable for 36 bearers in a paired 17 MHz spectrum or 52 bearers in a paired 25 MHz spectrum. The plan has three frequency groups (eg. frequency group 1 comprises frequency sets f1, f2 and f3) and a d/r ratio of 7 before polarisation re-use. The basic n=3 cell plan is retained i.e. each cell uses only one in 3 frequencies. Within each cell each frequency is re-used twice by base station sectoring. This frequency plan is more demanding on the base station front to back ratio (because the same frequencies are used in opposite cell sectors), but is less demanding on the subscriber station. The antenna arrangement according to the present invention providing antenna pairs having a common phase centre can be used to help meet the demands on the base station antenna requirements needed for this frequency plan. With the frequency plan of FIG. 7 the same polarisation can be re-used throughout, with a potential to double capacity through same sector polarisation re-use, for instance on a subset of bearers. FIG. 8 shows two types of possible self interference. The first type is direct co-channel interference from the base station which, because of the common phase centre of the antenna pair, will experience the same attenuation as the main signal (ie. correlated fading) and so the ratio of the strength of the main signal to the interference signal remains constant. Thus, the correlation of fading of wanted signals and co-channel interference can be maximised by having common phase centres from the bi-directional and co-channel transmissions. In the limit, the C/I term becomes part of the transmission modulation accuracy specification (e.g. 26 dB C/I=5% modulation accuracy error, which is good). The second type is back scatter interference from the environment and so its attenuation will not be correlated with respect to the main signal (ie. uncorrelated fading). Generally, polarisation is not preserved on the worst back scatter and so the transmission in the opposite direction will be at least partially oppositely polarised. Therefore this second type of interference can be significantly reduced by using different polarisations for different base station antennas. In the proposed frequency plan a way of enhancing the C/I ratio, at least for selected bearers, is that of tiering frequency re-use. By deleting one or more bearers from each sector, a subset of bearers avoid same cell re-use and could be assigned to problem calls. FIG. 9 shows a similar situation as that depicted in FIG. 8 save for the fact that the uplink is now in consideration and that other subscribers are factored in the calculations. The co-channel interference issues are determined by the near/far problem and the potential occurrence of un-correlated attenuation in two directions. The near/far problem can be mitigated by providing automatic power control (APC) at the subscriber terminal. If at the start of a call the transmission power is too high, co-channel interference is more likely. However, if the transmission power is too low then he likelihood of excessive Frame Error Rate (FER) is increased. By the provision of diversity, using the two tier antenna arrangement according to the present invention at the base station the problems are mitigated and enables the APC set point to be as low as -90 dBm. Other action to be considered is to raise the APC set point on a desired slot (logic channel) or handoff to another slot. Since uncorrelated fading occurs in two directions on both direct and back scattered co-channel interference, the provision of diversity improves reception considerably. The statistical gain advantage of choosing diversity over switched diversity significantly relaxes base station deployment criteria. If time division of the bearers is used it is preferred to synchronise the time slots of the 2 co-located antenna tiers according to the present invention.

An antenna arrangement for a fixed wireless access base station comprising at least one pair of directional antenna wherein the pair of antennas have a common phase centre. If both antenna in the pair then operate on the same frequency channels, the correlation of fading of same sector co-channel interference can be maximised. To provide full cell coverage a plurality of pairs of antenna are arranged spaced apart in a tier about a support and to provide spatial diversity a second tier of antenna substantially the same as the first and which is vertically separated from the first tier is added.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This is a Divisional Application of U.S. application Ser. No. 09/648,475, filed Aug. 25, 2000, which is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 1999-238095, filed Aug. 25, 1999, the entire contents both of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] The present invention relates generally to an optical recording medium, an optical recording and/or reproducing method and an optical recording and/or reproducing system. More specifically, the invention relates to an optical recording medium which has a phase change type optical recording layer irradiated with light beams for reproducing and recording/reproducing information and which has a greatly improved recording density and an extended operating wavelength range by utilizing a superresolution function, and an optical recording and/or reproducing method and optical recording and/or reproducing system which is capable of providing a greatly improved recording density and an extended operating wavelength range by utilizing a superresolution function. [0003] Optical recording media, which are irradiated with light beams for reproducing or recording/reproducing information, have been put to practical use, for various data files, such as voice data, image data and computer data, as recording devices having large capacity, rapid accessibility and medium portability, and the development thereof is expected in future. As an example of an optical recording medium, an optical disk will be described below. [0004] As measures to enhance the density of optical disks, there are various approaches, such as the shortening of the wavelength of gas laser for an original disk cutting, the shortening of the wavelength of a semiconductor laser serving as an operating light source, the increase of the numerical aperture of an objective lens and the decrease of the thickness of an optical disk substrate. Moreover, in the case of recordable optical disks, there are various approaches, such as the mark length record and the land group record. [0005] As effective density enhancing techniques other than these approaches, the “superresolution function” has been proposed and studied. This is a function which is obtained in a “superresolution film”. The “superresolution film” means a film having a characteristic that an optical response varies non-linearly in accordance with the intensity of irradiated light. [0006] That is, generally used laser beams have a light-intensity distribution which is like a Gaussian distribution. The superresolution film has different response characteristics to the central portion (high intensity portion) and peripheral portion (low intensity portion) of such a light beam. By such a spatial difference in optical response, an optical mask or aperture is formed in the central or peripheral portion of an incident light spot to reduce an effective spot size, so that a high-density recording and/or reproducing can be carried out. [0007] At first, such a superresolutionfunction was proposed as a technique which is special to optical magnetic disks. That is, optical magnetic disks use a medium wherein a magnetic film having the superresolution function is switched-connected or magnetostatic-connected to a recording layer or a reproducing layer. Then, during irradiation with regenerative light, the temperature of the film is raised to utilize the exchange force or magnetostatic force between layers, so that an optical mask or optical aperture to a part of a regenerative spot is formed in a superresolution film. [0008] Thereafter, a proposal for using a film material, which has a non-linearly varying optical response, without using magnetic functions, was made with respect to a read only memory disk. It was found that this proposal was applicable to all types of optical disks, such as optical recording ROM media, optical recording phase-change media and dye type recordable media, in addition to optical magnetic recording media. [0009] Such superresolution reproducing methods and superresolution reproducing films capable of being applied to various optical disks are divided broadly into a heat mode system and a photon mode system. As disclosed in, e.g., ISOM '98-Technical Digiest (P126), the former system is designed to irradiate a superresolution film with regenerative light to heat the superresolution to cause a phase transition, such as melting, in the superresolution film to change the transmittance thereof. In this system, the response time up to the formation of an optical aperture or mask is relatively long. As disclosed in, e.g., ISOM '98-Technical Digiest (p128), the latter photon mode system is designed to irradiate a superresolutionfilm with generative light to cause the electron transition in the superresolution film to change the light transmittance by the absorption saturated phenomenon. The photon mode system is characterized in that the response time up to the formation of an optical aperture or mask is relatively short. [0010] However, conventional optical recording media having superresolution films are limited to those having a monolayer superresolution film. However, in the case of the monolayer, there is a problem in that it is difficult to reduce the size of the optical aperture and to ensure a practical operating wavelength margin. SUMMARY OF THE INVENTION [0011] It is therefore an object of the present invention to eliminate the aforementioned problems and to provide an optical recording medium, an optical recording and/or reproducing method and an optical recording and/or reproducing system, wherein it is possible to greatly reduce the size of an optical aperture and to provide a higher density. [0012] It is another aspect of the present invention to provide an optical recording medium, an optical recording and/or reproducing method and an optical recording and/or reproducing system, which can easily ensure a practical operating wavelength margin. [0013] In order to accomplish the aforementioned and other objects, according to one aspect of the present invention, an optical recording medium comprises a superresolution film which has a light transmittance varying in accordance with the intensity of incident light and which has a superresolution function for optically masking part of incident light to form an optical aperture having a smaller size than a spot size of incident light, the superresolution film including at least two kinds of superresolution materials having different response times until the superresolution function occurs after being irradiated with light. [0014] With the above described construction, it is possible to easily and surely reduce the light spot size to greatly enhance the recording density. [0015] If the superresolution film comprises at least two kinds of stacked superresolution films having different response times until the superresolution function occurs after being irradiated with light, it is possible to easily and surely reduce the light spot size via only a portion in common between the apertures of the two kinds of superresolution films, so that it is possible to greatly enhance the recording density. [0016] Moreover, if the apertures formed in the at least two kinds of superresolution films when being irradiated with a light beam for writing or reading data partially overlap with each other, it is possible to easily and surely reduce the light spot size via only a portion in common between the apertures of the two kinds of superresolution films, so that it is possible to greatly enhance the recording density. [0017] According to another aspect of the present invention, an optical recording medium comprises a superresolution film which has a light transmittance varying in accordance with the intensity of incident light and which has a superresolution function for optically masking part of incident light to form an optical aperture having a smaller size than a spot size of incident light, the superresolution film including at least two kinds of superresolution materials having different operating wavelengths causing the superresolution function. [0018] With the above described construction, it is possible to greatly extend the operating wavelength range. [0019] If the superresolution film comprises at least two kinds of stacked superresolution films having different operating wavelengths causing the superresolution function, it is possible to surely, easily and greatly extend the operating wavelength range. [0020] In addition, if at least one kind of the at least two kinds of superresolution films is a superresolution film causing the superresolution function on the basis of electron transition, it is possible to easily select the response speed and operating wavelength by using a superresolution film of a photon mode system. [0021] Moreover, if at least one kind of the at least two kinds of superresolution films is a superresolution film causing the superresolution function on the basis of temperature rise, it is possible to easily select the response speed and operating wavelength by using a superresolution film of a heat mode system. [0022] According to another aspect of the present invention, an optical reproducing method comprises the steps of: preparing at least two kinds of superresolution films, each of which has a light transmittance varying in accordance with the intensity of incident light and each of which has a superresolution function for optically masking part of incident light to form an optical aperture having a smaller size than a spot size of incident light, the at least two kinds of superresolution films having different response times until the superresolution function occurs after being irradiated with light; irradiating the at least two kinds of superresolution films with a light beam for reading data so that the apertures formed in the at least two kinds of superresolution films partially overlap with each other, to irradiate an optical recording face of an optical recording medium with the optical beam via the optical apertures partially overlapping with each other; and detecting reflection of the light beam, with which the optical recording face is irradiated, to read data. [0023] With the above described construction, it is possible to easily and surely reduce the light spot size to greatly enhance the recording density. [0024] According to another aspect of the present invention, an optical reproducing method comprises the steps of: preparing at least two kinds of superresolution films, each of which has a light transmittance varying in accordance with the intensity of incident light and each of which has a superresolution function for optically masking part of incident light to form an optical aperture having a smaller size than a spot size of incident light, the at least two kinds of superresolution films having different operating wavelengths causing the superresolution function; irradiating the at least two kinds of superresolution films with a light beam for reading data to irradiate an optical recording face of an optical recording medium with the optical beam via the optical apertures; and detecting reflection of the light beam, with which the optical recording face is irradiated, to read data. [0025] With the above described construction, it is possible to greatly extend the operating wavelength range. [0026] According to a further aspect of the present invention, an optical reproducing system comprises: light irradiating means for irradiating at least two kinds of superresolution films, each of which has a light transmittance varying in accordance with the intensity of incident light and each of which has a superresolution function for optically masking part of incident light to form an optical aperture having a smaller size than a spot size of incident light, the at least two kinds of superresolution films having different response times until the superresolution function occurs after being irradiated with light, with a light beam for reading data so that the apertures formed in the at least two kinds of superresolution films partially overlap with each other, to irradiate an optical recording face of an optical recording medium with the optical beam via the optical apertures partially overlapping with each other; and data reproducing means for detecting reflection of the light beam, with which the optical recording face is irradiated by the light irradiating means, to read data. [0027] With the above described construction, it is possible to easily and surely reduce the light spot size to greatly enhance the recording density. [0028] According to a still further aspect of the present invention, an optical reproducing system comprises: light irradiating means for irradiating at least two kinds of superresolution films, each of which has a light transmittance varying in accordance with the intensity of incident light and each of which has a superresolution function for optically masking part of incident light to form an optical aperture having a smaller size than a spot size of incident light, the at least two kinds of superresolution films having different operating wavelengths causing the superresolution function, with a light beam for writing or reading data to irradiate an optical recording face of an optical recording medium with the optical beam via the optical apertures; and data reproducing means for detecting reflection of the light beam, with which the optical recording face is irradiated by the light irradiating means, to read data. [0029] With the above described construction, it is possible to greatly extend the operating wavelength range. [0030] According to the present invention, the spot size of a light beam for reproducing or recording information can be effectively reduced by stacking a plurality of superresolution films having different response times to irradiation with light. As a result, it is possible to improve spatial resolution and to realize a higher density optical recording. [0031] In addition, according to the present invention, the wavelength margin of a light beam for reproducing or recording information can be extended by stacking a plurality of superresolution films having different operating wavelengths. That is, it is not required to strictly manage the wavelength of laser light which is a light source, so that it is possible to simplify the recording and/or reproducing system. [0032] As described in detail above, according to the present invention, it is possible to realize a higher density optical recording with a simple construction to provide great industrial merits. BRIEF DESCRIPTION OF THE DRAWINGS [0033] The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiments of the invention. However, the drawings are not intended to imply limitation of the invention to a specific embodiment, but are for explanation and understanding only. [0034] In the drawings: [0035] FIG. 1 is a graph showing a typical light transmittance characteristic of a superresolution film; [0036] FIG. 2 is a conceptual diagram showing a basic function of a superresolution film; [0037] FIG. 3 is a conceptual diagram showing the relationship between the positions of a light spot and an optical aperture when taking account of a constant response time; [0038] FIG. 4A shows a part of an optical recording and/or reproducing system where an optical disk 511 is detachably mounted and rotated by a spindle motor 512 ; [0039] FIG. 4B is an enlarged cross-sectional view of the irradiated point Q shown in FIG. 4A ; [0040] FIG. 4C shows a schematic planar view of incident beam spot and the optical apertures of the supreresolution films; [0041] FIG. 5 is a schematic block diagri3m of an evaluating system for examining a time response of a superresolution film; [0042] FIG. 6 is a graph showing a typical example of a response characteristic of a superresolution film; [0043] FIG. 7 is a conceptual diagram showing an example of a sectional structure of a read only memory optical disk according to the present invention; [0044] FIGS. 8A and 8B are graphs showing the measured values of regenerative signals CNR examined using a track pitch (TP) and pit pitch as parameters; [0045] FIG. 9 is a schematic sectional view showing the construction of an example of a phase change medium according to the present invention; [0046] FIG. 10 is a graph showing a typical example of a wavelength dispersive characteristic of transmittance of a semiconductor; [0047] FIG. 11A is a graph schematically showing the dependence of transmittance on wavelength with respect to two kinds of superresolution films which have different wavelength response characteristics and which are used in the second preferred embodiment; [0048] FIG. 11B is a graph for explaining a condition of combination in the case of PM superresolution films; [0049] FIG. 12A is a graph showing two different absorption peak wavelengths of an HM film; [0050] FIG. 12B is a graph for explaining a condition of combination in the case of HM superresolution films; [0051] FIG. 13 is a schematic sectional view showing the construction of a preferred embodiment of an optical disk according to the present invention; [0052] FIG. 14 is a graph showing the evaluated results of the preferred embodiment of an optical disk according to the present invention; [0053] FIG. 15 is a block diagram of a principal part of a preferred embodiment of an optical recording and/or reproducing system according to the present invention; [0054] FIGS. 16A-16C show schematic cross sectional views of the optical recording media according to the present invention; and [0055] FIG. 16D is a graph showing transmittance characteristics of superresolution films for data-reading and data-writing. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0056] Referring now to the accompanying drawings, the preferred embodiments of the present invention will be described below. First Preferred Embodiment [0057] First, as the first preferred embodiment of the present invention, a technique for reducing the size of an optical aperture by preparing multilayer superresolutionfilms (or a monolayer mixed with a plurality of superresolution materials having different response times). [0058] FIG. 1 is a graph showing a typical light transmittance characteristic of a superresolution film. That is, this figure shows the dependence of the light transmittance on the intensity of irradiation light. [0059] FIG. 2 is a conceptual diagram showing a basic function of a superresolution film. [0060] As shown in FIG. 1 as an example, the light transmittance of the superresolution film varies in accordance with the intensity of irradiation light. In the example of FIG. 1 , the light transmittance is low when the intensity of irradiation light is low, and the light transmittance increases as the intensity of irradiation light increases. As shown in FIG. 2 as an example, if light having a Gaussian intensity distribution is incident on a superresolution film having such a characteristic, the high intensity portion of the incident light near the center of the light spot selectively passes through the film, and the low intensity portion of the incident light in the peripheral portion thereof is selectively shaded, so that the spot sizes of the transmitted light is smaller than that of the incident light. If light thus reduced is incident on the data recording surface of an optical recording medium, this is effectively equivalent to the shortening of the operating wavelength, so that it is possible to provide an improved resolution to enhance the quality of regenerative signals or provide an improved recording density. [0061] FIGS. 1 and 2 show an example of the case where the light transmittance of the superresolution film increases as the intensity of irradiation light increases. To the contrary, the light transmittance may decrease as the intensity of irradiation light increases. In that case, an optical mask is formed in the central portion of the spot of the incident light, and an aperture is formed in the peripheral portion thereof. [0062] In addition, although the above described optical aperture or mask may be formed by the variation in extinction coefficient (an imaginary number part k of a complex index of refraction), the optical aperture or mask may be formed by the variation in real number part n of the complex index of refraction with respect to the intensity of light. Also in this case, optical interference conditions vary in accordance with the spatial variation in real number part n, so that it is possible to spatially vary the light transmittance. [0063] The response time will be considered below. The response time depends on the material of the superresolution film. In general, the response time in the heat mode system is slow, and the response time in the photon mode is rapid. When data stored in the optical recording medium are read out or when data are recorded in the optical recording medium, the light spot rapidly moves relatively with respect to the medium. Therefore, taking account of the response time, the position of the optical aperture or mask formed in the superresolution film is not directly below the light spot, and lags toward the trailing edge (in the opposite direction to the traveling direction of the light spot). [0064] FIG. 3 is a conceptual diagram showing the relationship between the positions of a light spot and an optical aperture when taking account of a constant response time. That is, if the superresolution film is irradiated with a light spot P, an optical aperture O having a smaller size than the spot diameter of the light spot P is formed. Since the formation of the optical aperture O requires a predetermined response time, the light spot P is shifted in the traveling direction D thereof in the response time. In the example of FIG. 3 , since the optical aperture O is formed after the predetermined response time, a part of the optical aperture O projects to the outside of the light spot P. As a result, the light actually passing through the superresolution film corresponds only to a portion (oblique line portion) in common between the light spot P and the optical aperture O. That is, an optical reproduction or optical recording is carried out by a fine beam passing through the portion in common between the light spot P and the optical aperture O. As a result, it is possible to improve the spatial resolution to enhance the recording density. Furthermore, reference symbols τr, τp and τf in FIG. 3 will be described in detail later. [0065] On the other hand, the inventor has made the present invention providing a unique construction that a plurality of superresolution films having different response times are combined. That is, the optical aperture reducing technique as the first preferred embodiment of the present invention utilizes the difference between the response times of the plurality of superresolution films. [0066] FIGS. 4A-4C are conceptual diagrams showing an example of an optical aperture when a superresolution film having a short response time is combined with a super-resolution film having a relatively longer response time. FIG. 4A shows a part of an optical recording and/or reproducing system where an optical disk 511 is detachably mounted and rotated by a spindle motor 512 . A laser beam L is irradiated on the recording surface of the disk 511 through half mirror 536 and objective lens 540 . The enlarged cross-sectional view of the irradiated point Q is shown in FIG. 4B . [0067] As shown in FIG. 4B , the disk 511 has a layered structure including, for example, a first superresolution film 201 , a second superresolution film 202 , an optical interference film 252 and a recording film 254 on a transparent substrate 101 . The laser beam L is converged into a nearly parallel been within a depth of focus of the lens 540 . This parallel beam is launched into the layered structure of the disk 511 . [0068] The disk 511 is rotated in a direction shown by the arrow R in the figure. The first superresolution film 201 has a shorter response time and the second superresolution film 202 has a relatively longer response time. [0069] FIG. 4C shows a schematic planar view of incident beam spot and the optical apertures of the supreresolution films. In the figure, reference symbol P denotes a beam spot of the incident laser beam L, reference symbol A denotes an optical aperture which is formed by a superresolution film 201 , and reference symbol B denotes an optical aperture which is formed by a superresolution film 202 , respectively. [0070] Since the optical aperture A has the short response time, the optical aperture A is formed immediately after being irradiated with light. Therefore, the position of the aperture at the instant of the formation thereof is substantially the center of the light spot P. On the other hand, since the optical aperture B is formed after the predetermined response time as described referring to FIG. 3 , the light spot P is shifted in a direction opposite to the traveling direction R when the aperture B has been formed. [0071] Therefore, the light passing through the superresolution films 201 and 202 thus combined is limited only to the portion (cross-hatched portion) in common between the optical aperture A and the optical aperture B. That is, as can be seen from the comparison with FIG. 3 , it is possible to further reduce the size of an effective reproducing (recording) spot to improve the spatial resolution to realize a high density recording. [0072] The beam reducing effect as shown in FIGS. 4A-4C as an example can be suitably optimized in accordance with the kind of the adopted superresolution films and the recording and/or reproducing conditions (linear velocity, irradiation power, etc.). In a desired combination of superresolution films, one is a superresolution film of a photon mode system utilizing an electron transition, and the other is a superresolution film of a heat mode system. [0073] However, if a semiconductor is used among superresolution films belonging to the photon mode system, the response time varies in accordance with the kind of the semiconductor. In addition, if a film including semiconductor fine grains dispersed in a matrix, not a semiconductor continuous film, is used as a superresolution film, the response time can be varied by the size and density of the semiconductor fine grains and the kind of the matrix material. Therefore, both of two kinds of superresolution films 201 and 202 may be superresolution films of the photon mode system represented by the semiconductor system. [0074] In addition, since the response time can be varied if the light absorption factor or the like is varied even in the case of the heat mode system, both of two kinds of superresolution films 201 and 202 may be superresolution films of the heat mode system. [0075] The order of the stacking of two or more kinds of superresolution films may be determined by taking account of, e.g., the sensitivity of the respective superresolution films. That is, in general, a film having a low sensitivity, i.e., a film having a higher irradiation light intensity required to increase the light transmittance in FIG. 1 , is preferably provided on the incident side of light beams. [0076] The response time of superresolution films for use in the present invention can be examined as follows. That is, a sample being at rest is irradiated with a light beam (pump light) as a pulse, which has a power capable of forming an optical aperture, and simultaneously, the irradiated portion is irradiated with a light beam as a probe light, which has a power capable of forming no optical aperture. If the time response of the transmittance is measured by the probe light, it is possible to know the time response of the superresolution film. [0077] FIG. 5 is a schematic block diagram an evaluating system for examining the time response of a superresolution film. In FIG. 5 , reference number 1 denotes a pump light source, and reference number 2 denotes an optical path for pump light, reference numbers 31 and 32 denoting objective lenses for pump light, reference number 3 denoting a power monitor for pump light, reference number 5 denoting a probe light source, reference number 6 denoting an optical path for probe light, reference number 7 denoting a reflecting mirror, reference numbers 81 and 82 denoting objective lenses for probe light, reference number 9 denoting a power monitor for probe light, reference number 10 denoting an oscilloscope, and reference number 11 denoting a superresolution film serving as a sample. [0078] While the sample 11 is continuously irradiated with probe light, the sample 11 is pulse-irradiated with pump light. If the transmittance of the superresolution film is varied by the irradiation with pump light, the transmittance of the probe light varies, so that the intensity of the monitored light varies. The irradiation power density of the pump light may be controlled by adjusting the relative positions of a focal point, which is formed by the objective lens 31 , and the sample 11 . The sample 11 is irradiated with probe light at a smaller spot size than that of pump light, in order to efficiently detect the variation in transmittance. [0079] As an example, the sample 11 was irradiated with pump light having a pulse rising time (a time required to rise from a 10 % intensity of the peak intensity to a 90% intensity of thereof) of about 2 nanoseconds and a pulse width of 10 nanoseconds to examine the time variation in transmittance using probe light. The wavelengths of the pump light and probe light may be selected in accordance with the operating wavelength of the superresolution film. For the pump light, a wavelength variable dye laser based on YAG laser excitation was used at a wavelength of 660 nm, and for the probe light, a laser diode (LD) (semiconductor laser) having a wavelength of 660 nm was used. [0080] FIG. 6 is a graph showing a typical example of a response characteristic of a superresolution film. That is, this figure shows the variation in intensity of transmitted light with respect to time, wherein the solid line denotes pump light and the broken line denotes the measured value of the probe light. As “response times”, three kinds of times τr, τp and τf can be defined as shown in the figure. [0081] The time τr is a period of time from the rising of the intensity of pump light (a time at which the intensity reaches 10% of the peak intensity) to the rising of light passing through the superresolution film. The time τp is a period of time until the intensity of light passing through the superresolution film reaches its peak after the intensity of pump light reaches its peak. The time τf is a period of time from the falling of the intensity of pump light (a time at which the intensity falls to 10% of the peak intensity) to the falling of light passing through the superresolution film. [0082] These three kinds of response times τ depend on the characteristics of the superresolution film. If these response times are caused to correspond to the beam profile shown in FIG. 3 , the shifted quantity between the leading edges (the end portions in the spot traveling direction) of the light spot P and optical aperture O mainly corresponds to the τr, the shifted quantity between the centers of the light spot P and optical aperture O mainly corresponds to the τp, and the shifted quantity between the trailing edges (the end portions opposite to the light spot traveling direction) of the light spot P and optical aperture O mainly corresponds to the τf. [0083] If the trailing edge of the optical aperture O is positioned outside of the light spot P as shown in FIG. 3 as an example, the outside projecting portion does not contribute to reproducing (or recording). Throughout the specification, the τp will be used as the response time unless the response time is particularly specified. EXAMPLES OF FIRST PREFERRED EMBODIMENT [0084] Examples of the first preferred embodiment of the present invention will be described below. [0085] FIG. 7 is a conceptual diagram showing an example of a sectional structure of a read only memory optical disk according to the present invention. That is, in FIG. 7 , reference number 101 denotes an optical disk substrate, and reference number 102 denotes pre-pit signals formed on the surface of the substrate, reference number 201 denoting a first superresolution film, reference number 202 denoting a second superresolution film and reference number 301 denoting a reflecting film. [0086] In FIG. 7 , the substrate 101 is irradiated with light beams from the bottom, and the reflecting light from the reflecting film 301 is monitored to read pre-pit information. Furthermore, in conventional read only memory optical disks, a reflecting film is formed directly on a pre-pit without using any superresolution films, or even if a film having a superresolution function is provided, such a film is substantially a monolayer and has a single time response. [0087] The pre-pit was formed by using a high density mastering process using a Kr + ion laser as a light source, setting a shortest pit length of about 0.3 μm, a shortest track pitch of about 0.35 μm, and suitably changing the pit length, pit interval and track pitch. Although the details of evaluation will be described later, a beam having an e −2 diameter of about 1 μm was used to carry out regeneration operations to examine the amplitudes of a regenerative signals in the case of various pit lengths and track pitches to quantitatively examine the resolution enhancing effect based on superresolution films. [0088] The superresolution films 201 and 202 were selected from three combinations. That is, three combinations include a combination of a film of a photon mode system (a PM film) having a high speed time response with a film of a heat mode system (an HM film) having a relatively slow time response, a combination of a PM film with a PM film, and a combination of an HM film with an HM film. [0089] The PM film may be selected from dye films, photochromic films, semiconductor films and so forth. In this example, a semiconductor fine-grain dispersed film was adopted. Specifically, a material containing CdSSe semiconductor fine grains dispersed in SiO 2 was used. By extending an optical gap by fine granulation, an absorption edge serving as a dispersed film was set so as to have a size of about 650 nm. If this material is used, the principle of operation serving as a superresolution film is the saturation of absorption due to light excitation as described above. After examining the time response characteristic using the evaluating system of FIG. 5 , the time response (τp) was variable in the range of from 2 ns (nanoseconds) to 15 ns in accordance with the particle size. [0090] The fact that the response time is 2 ns means that a response is made without lagging behind the rising of the pulse of pump light and that an actual response time is less than 2 ns. When the size of CdSSe particles was great, the response time was long, and when it was small, the response time was short. This is based on the fact that if the particle size is small, energy bands are discrete due to the quantum size effect, so that the saturation of absorption is easy to occur. [0091] On the other hand, the HM film may be selected from a GeSbTe film having a composition facilitating a high speed crystallization, low melting point metal films of Sb, Bi, Te or the like, and thermochromic dyes. In this example, an Sb film was used. In order to enhance light absorption into the Sb film to enhance the sensitivity of the superresolution operation, interference films may be provided on the top and bottom of the Sb film if necessary. The time response of the variation in transmittance of the Sb film was also evaluated by the above described pump/probe system. As a result, the response of the Sb film depended on the thickness of the film, and was in the range of from 20 ns to 60 ns. When the thickness of the film was small, the heat capacity was small, and the response was quick. [0092] The response time of the HM film can also be controlled by dispersion. That is, there is adopted a structure that Sb is dispersed in, e.g., SiO 2 , similar to the above described PM film. In this case, the response time can be controlled by the size of Sb fine grains. As the particle diameter is small, the response is quick. With respect to the order of the stacking of superresolution films, if the HM film which is temperature-raised to about the melting point directly contacts the substrate, there is the possibility that the adoption of a practical resin substrate is limited. Therefore, in this example, the PM film was used as the first superresolution film 201 , and the HM film was used as the second superresolution film 202 . [0093] In the example of the combination of the PM film with the PM film, the first and second superresolution films 201 and 202 have different time responses. In the combination of the HM film with the HM film, a dielectric film (not shown) for heat insulation and optical interference was provided between the first HM film 201 and the substrate 101 . In addition, the PM film was formed by the simultaneous sputtering method using a semiconductor target and a dielectric target. In this simultaneous sputtering method, the percentage content of the semiconductor was controlled by adjusting the ratios of sputtering input to the respective targets, and the semiconductor fine-grain size was controlled by a sputter gas pressure, a sputtering power, and a bias power applied to the substrate if necessary, in addition to the percentage content of the semiconductor. [0094] First, an example of a combination of a PM film with a PM film will be described. [0095] As the PM film 201 , a semiconductor fine-grain dispersed film having a CdSSe percentage content of 40 vol %, a CdSSe mean particle diameter of 5 nm and a response time of 4 ns was used, and as the PM film 202 , a semiconductor fine-grain dispersed film having a CdSSe percentage content of 60 vol %, a CdSSe mean particle diameter of 15 nm and a response time of 10 ns was used. The thickness of each of the films was 50 nm. As the reflecting film 301 , a usual A 1 alloy film was used, and the thickness thereof was 100 nm. It is assumed that this optical disk is a disk A 1 according to the present invention. [0096] On the other hand, in the example of the combination of the PM film with the HM film, the above described PM film 201 having a thickness of 30 nm was stacked on the Sb film 202 having a response time of 40 ns. The thickness of the reflecting film 301 was 100 nm. It is assumed that this disk is a disk A 2 according to the present invention. [0097] In addition, in the example of the combination of the HM film with the HM film, after a ZnS—SiO2 film (not shown) having a thickness of 100 nm for both of heat insulation and interference was formed on the substrate 101 , the above described Sb film having a thickness of 20 nm and a response time of 30 ns was provided as the first superresolution film 201 , and Sb and SiO 2 were simultaneously sputtered to stack thereon the second superresolution film 202 having a thickness of 50 nm, an Sb percentage content of 50 vol %, an Sb mean particle diameter of 20 nm and a response time 25 ns. It is assumed that this disk is a disk A 3 according to the present invention. [0098] The inventor also prepared a comparative example in order to confirm the resolution enhancing effect of the present invention. That is, as the comparative example, a disk (a comparative disk C 1 ) having a reflecting film provided directly on a pre-pit, and a disk (a comparative disk C 2 ) having a monolayer superresolution film for use in the proposal for conventional superresolution disks, were prepared as usual read only memory disks, and were used for evaluating disks. The superresolution film in the comparative example was an Sb film having a thickness of 20 nm and a response time of 30 ns. [0099] This disk evaluation was carried out by means of an optical disk evaluating system using a LD having a wavelength of 660 nm as an operating light source. In this system, the NA of the objective lens is 0.6, and the spot size of incident light beams is an e −2 diameter of about 1 μm. In this spot size, intersymbol interference and crosstalk occur with respect to a disk having a pit length or pit interval of less than 1 μm, so that the intensity of a regenerative signal starts to fall. In a disk using only a reflecting film, in the case of a track pitch of 0.6 μm, it was difficult to obtain significant regenerative signals CNR if the pit pitch was less than 0.4 μm. [0100] FIGS. 8A and 8B are graphs showing the measured values of regenerative signals CNR examined using a track pitch (TP) and a pit pitch as parameters. In this example of measurement, 5 m/sec was selected as a linear velocity. That is, the passing time in the e −2 diameter of the light spot is 200 ns, and the passing time in the full width at half maximum (FWHM) is about 100 ns. The superresolution effect remarkably appears in a portion, in which the light intensity is strong within the range of the FWHM of the light spot. However, at a linear velocity of 5 m/sec, the FWHM passing time is 100 ns which is longer the τp of the superresolution film which is selected in this example. Therefore, the “overlapping portion” of the light spot with the optical aperture is formed, so that it is possible to carry out a significant superresolution reproducing operation. [0101] In the measurement, the regenerative power was optimized every disk. Because the optical aperture is too small so that the signal is insufficient if the power is too low and because the optical aperture is too large so that the resolution is damaged if the power is excessive. In this example, the regenerative power having the minimum product (highest density) of a pit pitch and a track pitch, which was able to obtain CNR of 45 dB, was examined every disk. Specifically, the regeneration of tracks having a constant track pitch and different pit pitches was carried out while changing the power, to obtain the relationship between the CNR and the pit pitch, so that data capable of obtaining the highest CNR with respect to the regenerative power was shown in FIGS. 8A and 8B . [0102] FIG. 8A shows the measured results at TP=0.4 μm, and FIG. 8B shows the measured results at TP=0.6 μm. As can be clearly seen from the figures, the resolution of the disk having two superresolution films having different time responses according to the present invention is greatly improved as compared with the conventional disk C 1 having no superresolution film and the conventional disk C 2 having a single superresolution film. Among the examples of the present invention, the disk A 2 comprising the combination of the PM film with the HM film was most effective, and had the greatest difference between the response times of the first and second superresolution films. [0103] The inventor carried out the same experiments as those in FIGS. 8A and 8B , at various linear velocities of the disk. As a result, it was found that good results can be obtained in the following ranges assuming that the response time of a superresolution film having a shorter response is τ p1 , the response time of a superresolution film having a slower response is τ p2 , and the FWHM passing time of the light spot is ts. Ts/ 8≦τ p2 ≦ts/ 2 τ p2 /8≦τ p1 ≈p 2 [0104] If τ p2 is too long with respect to the spot passing time, the “overlapping portion” of the light spot with the optical aperture of the superresolution film having the quick response is too small, so that the signal strength is reduced. On the other hand, if τ p2 is too short with respect to the spot passing time, the optical apertures of the two superresolution films are too close to each other, so that the resolution enhancing effect based on the double layer is not remarkable. [0105] The relationship between τ p1 and τ p2 is the same. In addition, the desired relationship between ts, τ p1 and τ p2 depends on the used regenerative power and the power response of the superresolution films. Therefore, in the optical recording medium according to the present invention, it is also important to select a reproducing method capable of remarkably obtaining the effect. [0106] While the present invention has been applied to the read only memory optical disk in the examples, the present invention should not be limited thereto. That is, the present invention may be applied to rewritable phase-change media and optical magnetic media. [0107] FIG. 9 is a schematic sectional view of an example of a phase change medium according to the present invention. That is, a first superresolution film 201 , a second sure-resolving film 202 , and a phase-change medium film part 250 of a multilayer film may be sequentially formed on an optical disk substrate 101 having a tracking group. The first and second superresolution films 201 and 202 may have the same construction as those in the above described example. If necessary, a dielectric film is provided between the substrate 101 and the first superresolution film 201 or between the superresolution film 202 and the phase-change medium film part 250 . [0108] For example, the phase-change medium film part 250 comprises a first interference film 252 of ZnS.SiO 2 , a recording film 254 of SeSbTe, a second interference film 256 of ZnS.SiO 2 and a reflecting film 301 of an Al alloy are stacked sequentially in that order from the light incident side. [0109] If the response of the superresolution film is adjusted so that the optical aperture is open at a regenerative power level, when the superresolution film is irradiated with recording light having a power about ten times as large as the regenerative power or with erasing light having a power about five times as large as the regenerative power, the beam reducing effect decreases. Therefore, the recording mark size is defined by the incident light spot size, i.e., wavelength and NA, (this is slightly smaller than that when no superresolution film is provided). However, since the resolution can be greatly improved during regeneration, the recording mark pitch can be reduced to carry out a recording. The read only memory disk can carry out a very high density recording since the recording density can be defined by a mastering machine. According to the present invention, it is possible to surely read such a high density disk. On the other hand, when the present invention is applied to a recordable optical disk having the construction shown in FIG. 9 , a high density can be achieved due to the reduction of the mark pitch and track pitch although the recording density may be slightly reduced. [0110] On the other hand, while the wavelength was 660 nm in the above described example, the present invention should not be limited to such a wavelength. When a semiconductor fine-grain dispersed film is used, the operating wavelength may be a short wavelength of, e.g., about 400 nm to about 410 nm, by adjusting the material, grain density and particle diameter of the semiconductor. [0111] The semiconductor material may be selected in accordance with the wavelength of the used laser, and may be selected from Cu, halides of Ag, oxides of Cu, AgSe, AgTe, SrTe, SrSe, CaSi, ZnS, ZnO, ZnSe, ZnTe, CdS, CdSe, CdTe, AlTe, InS, InO, InSe, InSe, InTe, AlSb, AlN, AlAs, GaN, GaP, GaAs, GaSb, GeS, GeSe, SnS, SnSe, SnTe, PbO, SiC, AsTe, AsSe, SbS, SbSe, SbTe, BiS, TiO, MnSe, MnTe, FeS, MoS, CuAlS, CuInS, CuInSe, CuInTe, AgInS, AgInSe, AgInTe, ZnSiAs, ZnGeP, CuSbS, CuAsS, AgSbs and AgAsS. [0112] On the other hand, the matrix, in which the semiconductor fine grains are dispersed, may be selected from transparent dielectric materials, such as SiO 2 , Si 3 N 4 , Ta 2 O 5 , TiO 2 and ZnS.SiO 2 , C—H and C—F plasma polymer materials, and C. [0113] The number of the superresolution films should not be limited to two, but three or more superresolution films may be stacked. Second Preferred Embodiment [0114] As the second preferred embodiment, of the present invention, a technique for preparing multilayered superresolution films (or a monolayer mixed with a plurality of superresolution materials having different response times) to extend the range of operating wavelength. [0115] FIG. 10 is a graph showing a typical example of a wavelength dispersive characteristic of transmittance of a semiconductor. In the case of the solid line of FIG. 10 , the intensity of the monitored light is sufficiently low to correspond to the state that the transmittance is low in FIG. 1 . When such a semiconductor is used as the material of the superresolution film, the semiconductor is set so that a portion near its base absorption edge has an operating wavelength. In the operating wavelength, electrons are excited from the filled band to the conduction band by the irradiation with light (more generally, optional two levels may be selected) to absorb light. If the light intensity is sufficiently high to excite most of electrons from the lower level to the upper level, the light absorption does not occur due to the absorption saturated phenomenon, so that the transmittance rises to appear the superresolution function. [0116] If the absorption saturated phenomenon is grasped as the axis of wavelength (axis of energy), this is equivalent to the extension of the optical gap of the semiconductor. That is, a spectrum shown by the solid line in FIG. 10 during low power irradiation is shifted toward a short wavelength during high rower irradiation as shown by the broken line in FIG. 10 . In order to promote the superresolution function, the variation in transmittance is preferably greater by a smaller amount of wavelength shift from the point of view of sensitivity and contrast. In addition, the transmission spectrum preferably varies rapidly with respect to wavelength near the base absorption edge. [0117] However, these characteristics are not desired in order to extend the operating wavelength range. For example, if the operating wavelength is extended to a longer wavelength range than the wavelength shown in FIG. 10 , the transmittance is high both during low power irradiation (solid line data) and during high power irradiation (broken line data), although there is no problem if the operating wavelength is the wavelength shown in FIG. 10 . [0118] FIG. 11A is a graph schematically showing the dependence of transmittance on wavelength with respect to two kinds of superresolution films which have different wavelength response characteristics and which are used in this preferred. embodiment. For example, when semiconductor fine-grain dispersed films are used as superresolution films, films having different base absorption edges are stacked. In addition, the respective superresolution films are adjusted so that the transmittance on the shorter wavelength side than the base absorption edge is not so low. Specifically, as shown in the example of FIG. 11A as an “operating range”, although the transmittance of one of the superresolution films is set to be sufficiently high, the transmittance of the other superresolution film is set to be sufficient in the optical aperture even if it operates in a wavelength which is not so high. Such adjustment of transmittance can be carried out by the adjustment of the material and thickness of the respective superresolution films. [0119] In the example of FIG. 11A , the operable wavelength range can be extended to about twice as large as that when a monolayer superresolution film is used. The effects of the multilayering of superresolution films to extend the operating wavelength range are great particularly with respect to superresolution films of the photon mode system, which have rapid wavelength response. [0120] In the case of heat mode system, as shown in FIG. 12A , since the light transmittance varies with respect to wavelength even in the case of superresolution films of the heat mode system, the temperature of the films, i.e., the size of the optical aperture or mask depends on wavelength, so that it is possible to obtain the effects of the multilayering to extend the operating wavelength range. [0121] In order to extend the operating wavelength range effectively, it is preferable to combine superresolution films whose operating wavelengths are to some extent approximate each other. FIGS. 11B and 12B are schematic diagrams for explaining this condition of the combination. [0122] First, the condition of combination in the case of PM films is explained below referring to FIG. 11B . FIG. 11B shows a transmittance characteristics of PM films A and B. A center point of the full variable range of the transmittance is defined as AC. The upper half variable range above the center point AC and the lower half variable range below the center point AC are defined as AM and AM, respectively. Similarly, the center point BC and the half variable range are defined for superresolution film B. [0123] Then a point shifted by 50% of the half variable range AM (AM/2) from the center point AC is defined as AP, and the corresponding wavelength is defined as λAM/2. The point of the superresolution film B corresponding to this wavelength λAM/2 is defined as BP. [0124] Under the above-explained definitions, it is preferable that the point BP is more than 25% away from the edge of the variable range. That is, in FIG. 11B , the distance BH may preferably be longer than BM/4. When this condition is met, the operating wavelengths of PM films A and B are close enough to extend the operating wavelength of the system effectively. [0125] Next, the condition of combination in the case of HM films is explained below referring to FIG. 12B . In the case of HM films, the peaks of absorbance are defined as center points AC and BC, respectively. The variable ranges AM anal BM are defined as shown in the figure. Then a point shifted by 50% of the variable range (AM/2) from the center point AC is defined as AP, and the corresponding wavelength is defined as λBAM/2. The point of the superresolution film B corresponding to this wavelength λAM/2 is defined as BP. [0126] Under the above-explained definitions, it is preferable that the point BP is more than 25% away from the bottom of the variable range. That is, in FIG. 12B , the distance BH may preferably be longer than BM/4. When this condition is met, the operating wavelenghs of films A and B are close enough to extend the operating wavelength of the system effectively. [0127] The above-explained conditions are necessary for either one or another film of the combination. The conditions need not to be met for both of the films to be combined at the same time. According to the present invention, by combining such superresolution films having operating wavelengths close to each other, the operating wavelength of the system can be effectively extended. EXAMPLES OF SECOND PREFERRED EMBODIMENT [0128] Examples of the second preferred embodiment of a multilayer superresolution optical disk for extending an operating wavelength range according to the present invention will be described below. The sectional structure of the optical disk in this preferred embodiment is the same as that in FIG. 7 . Two superresolution films suitable for this preferred embodiment are films having the dependence of transmittance on wavelength shown in FIG. 11 in the case of PM films, and films having the dependence of transmittance on wavelength shown in FIG. 12 in the case of HM films. [0129] The semiconductor fine-grain dispersed type PM films having different base absorption edges shown in the example of FIG. 11 can be obtained by, e.g., simultaneously sputtering CdSSe and SiO 2 to adjust the particle diameter of SdSSe. A film having a mean particle diameter of 2 nm has a base absorption edge on the short wavelength side (near 650 nm) as shown by the solid line in FIG. 11 , and a film having a mean particle diameter of 10 nm has a base absorption edge near 655 nm. [0130] In the case of the HM film shown in FIG. 12 as an example, it is difficult to form different two absorption peak wavelengths in, e.g., a single Sb film. However, if interference films are arranged on the top and bottom of the superresolution film, the dependence of absorption on wavelength can be adjusted by the multiple interference effect. In addition, if an Sb film and a Te film are stacked and if an interference film is sandwiched therebetween, the absorption peak wavelength can be suitably adjusted. [0131] FIG. 13 is a conceptual diagram showing the sectional construction of an optical disk in this example. That is, a ZnS—SiO 2 film 401 having a thickness of 100 nm, a first superresolution film 201 of Sb having a thickness of 20 nm, a ZnS—SiO 2 film 402 having a thickness of 15 nm, a second superresolution film 202 of Te having a thickness of 10 nm, a ZnS—SiO 2 film 402 , having a thickness of 15 nm, and a reflecting film 301 of an Al alloy having a thickness of 100 nm are sequentially stacked on a substrate 101 . The absorption peak wavelength of the first superresolution film 201 was adjusted to be 650 nm, and the absorption peak wavelength of the second superresolution film 202 was adjusted to be 660 nm. The absorption characteristics of the films 201 and 202 were adjusted so that the condition explained with regard to FIG. 12B could be met. [0132] The adjustment of the absorption peak wavelength can be carried out by measuring the dependence of optical constants of the respective layers on wavelength by means of an ellipsometer to optically calculate the thickness of each of the layers. Also in this preferred embodiment similar to the above described first preferred embodiment, both of a PM film and a HM film may be used as the first and second superresolution films 201 and 202 . As described above, in the case of the combination of semiconductor fine-grain dispersed type PM films having base absorption edges at 650 nm and 655 nm, some operations of a disk was attempted at operating wavelengths of 635 nm to 680 nm. Operation conditions were set so as to have TP=0.4 μm, a pit pitch of 0.5 μm and a linear velocity of 5 m/sec. The regenerative power was selected so as to have the optimum value at each wavelength. The way of selecting the optimum value is the same as that in the above described first preferred embodiment. [0133] When a semiconductor fine-grain dispersed film was used as the superresolution film, the optimum regenerative power was shifted toward a high power as the operating wavelength was shorter, since a power density required to saturate absorption increases as the wavelength is shifted from the base absorption edge to a shorter wavelength. [0134] FIG. 14 is a graph showing the evaluated results of an optical disk in this preferred embodiment. That is, this figure shows the dependence of CNR with respect to the regenerative wavelength. In this figure, the solid line corresponds to a case where two superresolution films having different wavelength responses are used according to the present invention, and the broken line corresponds to a case where a monolayer superresolution film having a base absorption edge near 650 nm is used as a comparative example. In FIG. 14 , a range capable of obtaining a CNR having 45 dB or more is a broad range of 635 nm to 665 nm in the case of an optical disk according to the present invention (solid line), whereas it is a narrow range of 635 nm to 654 nm in the case of the comparative example. That is, according to the present invention, it is possible to extend the operating wavelength range. [0135] In addition, the number of superresolution films should not be limited to two, but three or more superresolution films may be stacked. [0136] Furthermore, disks applied to the second preferred embodiment of the present invention should not be limited to read only memory disks, but this preferred embodiment may be applied to phase-change media and optical magnetic media. In addition, there is no limit to the way of selecting the operating wavelength. Third Preferred Embodiment [0137] Finally, an optical reproducing system, which can suitably use an optical recording medium according to the present invention, will be described below. [0138] FIG. 15 is a block diagram showing a principal part of a preferred embodiment of an optical reproducing system according to the present invention. That is, the optical reproducing system shown in this figure as an example is a recording/reproducing type optical disk system also having a recording function, and has a light irradiation means for irradiating with light, a data reproducing means for reading data and a data recording means for writing data. FIG. 15 also shows a state that a disk 511 serving as an optical recording medium is mounted. [0139] The disk 511 is detachably mounted in an optical recording and/or reproducing system, and rotated by a spindle motor 512 when it is mounted therein. [0140] An optical pickup has a laser light source for irradiating the recording face of the optical disk 511 with light beams, and a photo detecting system for detecting reflecting beams from the recording face. [0141] The light irradiation means has a laser light source, provided in a pickup 513 , for irradiating the light irradiated face of the optical disk 511 with optical beams. At this time, the light irradiated face is irradiated with optical beams via the above described superresolution film in any one of the first and second preferred embodiments. Such a superresolution film is most preferably provided in the optical disk 511 , but it may be provided between the optical disk 511 and the optical pickup 513 or in the optical pickup 513 . [0142] The optical pickup 513 is moved and adjusted by a servomotor 514 , and driven by a laser driver 525 to irradiate the optical disk 511 with laser light to optically record and/or reproduce information. The spindle motor 512 and the servomotor 514 are driven and controlled by a drive controller 522 via a drive control circuit 524 . [0143] The data reproducing means includes a photo detecting system provided in the optical pickup 513 , and a regenerative signal processing circuit. The regenerative signal circuit has a preamplifier 515 , a variable gain amplifier (VGA) 516 , an A/D converter circuit 517 , a linear equalizer circuit 518 , a data detecting circuit 520 and a decoder 521 . The pre-amplifier 515 and the VGA 516 are designed to amplify a regenerative signal which is read by the optical pickup 513 . The A/D converter circuit 517 is designed to convert the amplified regenerative signal to a digital signal which is a quantized sample value of discrete time. [0144] The linear quantizer circuit 518 is a kind of digital filter. For example, the data detecting circuit 520 is a signal processing circuit of a maximum likelihood series estimating system for detecting data from a regenerative signal waveform which is equalized by a partial response. Specifically, the data detecting circuit 520 comprises a viterbi decoder. The decoder 521 is designed to restore a sign bit string, which is detected by the data detecting circuit 520 , to the original recorded data. [0145] The data recording means has a laser driver 525 and a modulator circuit 526 . The modulator circuit 526 is designed to carry out a coding processing for converting recorded data, which are transmitted from the drive controller 522 , to a predetermined sign bit string. The laser driver 525 is designed to drive the optical pickup 513 so as to record marks, which correspond to the code bit string outputted from the converter circuit 526 , on the disk 511 . [0146] Furthermore, it is not always required to have a series of data storing means, and it may be a system having only a data reproducing means, i.e., an optical reproducing system. [0147] The drive controller 522 is a main control system of the system. The drive controller 522 is connected to, e.g., a personal computer or a television receiver, via an interface 523 to carry out the transfer and control of recorded and/or reproduced data. Furthermore, this system include a dynamic image compressing circuit (not shown) and dynamic image decompressing circuit (not shown), which are required to record and/or reproduce image information, and an error detecting/correcting circuit for carrying out an error detection/correction processing (not shown) for data which are demodulated by a demodulator circuit 520 . [0148] If the optical recording medium 511 is recordable, the formation of erasing light for erasing recorded data is carried out in, e.g., the modulator circuit 526 . That is, the modulator circuit 526 is designed to carry out a coding processing for converting recorded data, which are transmitted from the drive controller 522 , to a sign bit string. For example, in the case of a phase change type recording medium, the modulator circuit 526 is designed to generate erasing light or its pulse train, which has a smaller erasing power level than a recording power level, as a signal for erasing data. [0149] This erasing light is determined so as to heat the recording layer part of the optical disk to a temperature zone having a high crystal growth rate Rg and a temperature zone having a high crystalline nucleus producing frequency v x, respectively. Therefore, the kind, level, width and number of pulses constituting the erasing light are suitably determined in accordance with the material of the recording layer part and optical characteristics of the laser. [0150] In addition, it is desired to optimize the regenerative light power in accordance with the linear velocity when reproduction is carried out. Because the optical aperture is too small so that the signal strength is insufficient if the power is too low, and because the aperture is too large so that the resolution is damaged if the power is excessive. [0151] The above described reproducing system according to the present invention is designed to irradiate the recording face of the optical disk with light beams via the above described superresolution film in the first or second preferred embodiment. Therefore, the reproducing system according to the present invention has following structural characteristics. [0152] First, in the reproducing system according to the present invention, the passing time of the light spot, i.e., (e −2 diameter/linear velocity), is controlled so as not to be higher than τr of a superresolution film having a slow response, and more preferably controlled so as not to be higher than τp. Because this corresponds to a rate, at which the optical aperture is formed in the superresolution film. [0153] Secondly, in the reproducing system according to the present invention, the power of the recording light beams is controlled so as to be within a range which is necessary and sufficient to vary the transmittance of the superresolution film. Specifically, assuming that the power of the regenerative light beams is Pr and the irradiation light intensity for varying the variation in transmittance of the superresolution film is P, a relationship of P≦Pr≦3P is preferably established. The irradiation light intensity P is an irradiation light intensity near the center of a portion, in which the transmittance changes, in the graph of FIG. 1 . Because, if Pr is smaller than the above described range, the optical aperture is difficult to be formed in the superresolution film, whereas if Pr is greater than the above described range, there is some possibility that data are erased or written in the optical recording medium and that the superresolution film is deteriorated by irradiation with light. [0154] Thirdly, in the reproducing system according to the present invention, Pr is controlled in accordance with the variation in linear velocity of light beams so that the linear velocity of light beams is within the range of the passing time of the light spot described in the above described first characteristic and satisfies the range described in the above described second characteristic. That is, from the point of view of the reproducing energy density, the range of Pr varies in accordance with the linear velocity, so that it is required to adapt this variation. [0155] Fourthly, the reproducing system according to the present invention selectively has means for carrying out a test reproduction or a test recording and/or reproduction with respect to the optical disk and for determining the conditions satisfying the above described first through third characteristics. That is, there is some possibility that the optimum of the passing time of the light spot and the optimum value of the regenerative power are different every optical disk. Therefore, the test reproduction or test recording and/or reproduction may be carried out to examine their optimum values to carry out a reproduction on the basis of the obtained optimum values. [0156] On the other hand, in addition to the examples described with regard to the first and second embodiment of the invention, various structures can be employed for the optical recording medium of the present invention as well. [0157] FIGS. 16A-16C show schematic cross sectional views of the optical recording media according to the present invention. [0158] First, the recording medium shown in FIG. 16A has a layered structure including a first superresolution film 201 R, a second superresolution film 202 R, a first optical interference film 252 , a recording film 254 , a second optical interference film 256 , a third superresolution film 201 W and a reflecting film 301 , on a transparent substrate 101 . [0159] The substrate 101 , a first optical interference film 252 , a recording film 254 , a second optical interference film 256 and a reflecting film 301 can be similar to the ones explained with regard to FIGS. 7, 9 and 13 . [0160] The first and second superresolution films 201 R and 202 R have a similar features as the ones explained with regard to the first and second embodiments of the invention. Thus, these superresolution films effectively reduce the spot size of the data-reading laser beam to achieve the much improved resolution. The third superresolution film 201 W reduces the spot size of the data-writing laser beam. [0161] FIG. 16D is a graph showing transmittance characteristics of superresolution films for data-reading and data-writing. The horizontal axis of the graph shows input power of the incident laser beam and the vertical axis shows transmittance of the superresolution films. [0162] In the case of the rewritable medium, a power of the data-erasing laser beam P E is about five times larger and a power of the data-writing laser beam is about ten times larger than that of the data-reading laser beam P R , respectively. The first and second superresolution films 201 R and 202 R have transmittance characteristics which correspond to the power level of the data-reading beam P R . The third superresolution film 201 W has a transmittance characteristics which corresponds to the power level of the data-writing beam P w . [0163] As can be seen in FIG. 16D , when data-erasing or data-writing is performed, the transmittances of the first and second superresolution films 201 R, 202 R are at high level, thus the laser beam can reach the recording layer 254 without obstructed. The laser beam is then partially absorbed by the recording layer 254 then transmits therethrough. [0164] The recording medium is designed so that only the absorbed energy at this stage is not enough to cause a data-writing even if the irradiated power level is at P w . The recording medium is adjusted so that the recording layer 254 is heated up to its data-writing temperature when the beam reflected by the layer 301 irradiates the recording layer 254 . Such adjustment can be done by properly designing the material of the layer 254 , intensity of the incident laser beam L and/or optical characteristics of the interference films 252 and 256 . [0165] Thus, when the data-writing beam having a power P w is irradiated, the spot size of the beam transmitted through the recording layer 254 is reduced by the third superresolution film 201 W and reflected by the layer 301 to irradiate the layer 254 . The irradiated part of the recording layer 254 is heated up to the data-writing temperature. Accordingly, a data-writing with a high resolution can be made by utilizing an assistance of a reflected beam whose spot size is reduced by the third superresolution film 201 W. [0166] In the case of the optical recording medium shown in FIG. 16B ,a layered structure including a first superresolution film 201 R, a first optical interference film 252 , a recording film 254 , a second optical interference film 256 , a second superresolution film 201 W, a third superresolution film 202 W and a reflecting film 301 is formed on a transparent substrate 101 . [0167] In this specific example, the spot size of a data-reading laser beam is reduced by the first superresolution film 201 R, thus a data-reading with a high resolution can be performed. [0168] On the other hand, the spot size of a data-writing laser beam is reduced by the second and the third superresolution films 201 W and 202 W. The reduced beam is reflected by the layer 301 then irradiates the recording layer 254 , thus the irradiated part is heated up to form a recording pit. The second and the third superresolution films 201 W and 202 W have a similar features as the ones explained with regard to the first and second embodiments of the invention. [0169] In the case of the optical recording medium shown in FIG. 16C , a layered structure including a first superresolution film 201 R, a second superresolution film 202 R, a first optical interference film 252 , a recording film 254 , a second optical interference film 256 , a third superresolution film 201 W, a fourth superresolution film 202 W and a reflecting film 301 is formed on a transparent substrate 101 . [0170] In this specific example, the spot size of a data-reading laser beam is reduced by the first and the second superresolution films 201 R and 202 R, thus a data-reading with a high resolution can be performed. [0171] On the other hand, the spot size of a data-writing laser beam is reduced by the second and the third superresolution films 201 W and 202 W. The reduced beam is reflected by the layer 301 then irradiates the recording layer 254 , thus the irradiated part is heated up to form a recording pit. [0172] The first and the second superresolution films 201 R and 202 R, and the third and the fourth superresolution films 201 W and 202 W have a similar features as the ones explained with regard to the first and second embodiments of the invention, respectively. [0173] Referring to the examples, the preferred embodiments of the present invention have been described. However, the present invention should not be limited to these examples. [0174] For example, while the four-layer structure comprising the first interference film, the recording film, the second interference film and the reflecting film which have been stacked in that order from the substrate side has been used in the examples of FIGS. 9 and 16 A- 16 C a five-layer structure having an Au translucent film provided in the four-layer structure may be used as well. [0175] In addition, in the case of the five-layer film structure, the translucent layer may be selected from silver (Ag), copper (Cu) and silicon (Si) films in addition to the Au film, and from a film having a structure wherein metal fine grains are dispersed in a dielectric matrix. The interference layer may be suitably selected from dielectric films of Ta 2 O 5 , Si 3 N 4 , SiO 2 , Al 2 O 3 and AIN in addition to ZnS—SiO 2 . The recording layer may be selected from chalcogen films of InSbTe, AgInSbTe and GeTeSe in addition to GeSbTe. The reflecting layer may be suitably selected from Al alloy films of AlCr and AlTi in addition to AlMo. [0176] Moreover, while the optical disk has been described as an example of an optical recording medium in the above described examples, the present invention should not be limited thereto. For example, the present invention may be applied to various optical recording media, such as an optical recording card, to obtain the same effects. [0177] While the present invention has been disclosed in terms of the preferred embodiment in order to facilitate better understanding thereof, it should be appreciated that the invention can be embodied in various ways without departing from the principle of the invention. Therefore, the invention should be understood to include all possible embodiments and modification to the shown embodiments which can be embodied without departing from the principle of the invention as set forth in the appended claims.

A tool attachable to a spindle of a machine tool in the same way as an ordinary tool, capable of being driven without connecting with an external power supply etc., giving a higher rotational speed than that of the spindle of the machine tool without supplying electric power from the outside, and able to be changed automatically, provided with a machining tool for machining a workpiece, a motor for driving the machining tool, a generator for generating electric power to drive the motor by the rotation of the spindle, and a breaker for breaking a supply line of electric current from the generator to the motor when electric current over a predetermined value flows in the supply line.

CROSS REFERENCES TO RELATED APPLICATIONS [0001] The present invention contains subject matter related to Japanese Patent Application JP 2006-296532 filed in the Japanese Patent Office on Oct. 31, 2006 and Japanese Patent Application JP 2007-093349 filed in the Japanese Patent Office on Mar. 30, 2007, the entire contents of which being incorporated herein by references. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a semiconductor element in which a plurality of circuits such as, for example, an analog circuit and a digital circuit are mounted on a semiconductor substrate, and a semiconductor device and a mounting board including the semiconductor element, more particularly to a semiconductor element, a semiconductor device and a mounting board which are preferably used in the case where while a digital circuit uses a large-amplitude signal, an analog circuit uses a small signal of a few μV to a few mV. [0004] 2. Description of the Related Art [0005] With an improvement in frequency characteristics of a CMOS (Complementary Metal Oxide Semiconductor) process in recent years, an analog circuit can be formed together with a digital circuit on one chip by the CMOS process. However, in the case where the analog circuit and the digital circuit are formed on one chip, compared to the case where the analog circuit and the digital circuit are separately formed on different chips, the digital circuit is positioned closer to the analog circuit, so in particular, in the case where while the digital circuit uses a large-amplitude signal, the analog circuit uses a small signal of a few μV to a few mV, noises generated in the digital circuit may exert an influence on the analog circuit. Therefore, typically, the analog circuit is arranged as far from the digital circuit which may be a noise source as possible in a chip. [0006] FIG. 30 shows a plan view of a typical semiconductor element 100 in which an analog circuit 110 and a digital circuit 120 are mounted on a p-type semiconductor substrate 140 . In FIG. 30 , an interlayer insulating film 141 and a passivation layer 142 (which will be described later) of the semiconductor element 100 are not shown. FIG. 31 shows a simplified sectional view (that is, some parts are not shown) taken along a line A-A viewed from an arrow direction, and a parasitic capacity C 101 formed between an n-type source region 111 or an n-type drain region 112 and the p-type semiconductor substrate 140 . FIG. 32A shows a sectional view taken along a line B-B viewed from an arrow direction, and FIG. 32B shows a parasitic resistance R 101 formed between a via 131 and a p-type semiconductor region 133 in a sectional view of FIG. 32A . [0007] It is obvious from FIG. 30 that the analog circuit 110 is arranged in a corner of the chip in order to be arranged away from the digital circuit 120 which may be a noise source. For example, as simply shown in FIG. 31 , the analog circuit 110 is electrically connected to the p-type semiconductor substrate 140 through the n-type source region 111 or the n-type drain region 112 of a transistor included in the analog circuit 110 and the parasitic capacity C 101 . Therefore, at a certain frequency or higher, the analog circuit 110 is coupled to the p-type semiconductor substrate 140 with low impedance, and the analog circuit 100 is susceptible to the potential of the p-type semiconductor substrate 140 . In addition, the interlayer insulating film 141 and the passivation layer 142 formed by laminating a SiO 2 layer 142 A and a polyimide layer 142 B in this order are laminated on the p-type semiconductor substrate 140 . [0008] As shown in FIG. 33 , the potential of the p-type semiconductor substrate 140 directly below the analog circuit 110 is susceptible, because noises generated in the digital circuit 120 propagate through the p-type semiconductor substrate 140 as a path path 1 . Therefore, in some cases, it is necessary to reduce noises (substrate noises) propagating through the path path 1 . [0009] Therefore, for example, as shown in FIG. 34 , it can be considered that a deep n-type well layer 143 and an n-type well layer 144 which separate the analog circuit 110 from the other portion of the p-type semiconductor substrate 140 are arranged (refer to Japanese Unexamined Patent Application Publication No. 2004-179255). Thereby, as shown in FIG. 34 , a parasitic capacity C 102 is formed at an interface between the deep n-type well layer 143 and the n-type well layer 144 on a side closer to the analog circuit 110 , and a parasitic capacity C 103 is formed at an interface between the deep n-type well layer 143 and the n-type well layer 144 on a side opposite to the side closer to the analog circuit 110 , and the analog circuit 110 is electrically connected to the p-type semiconductor substrate 140 through the parasitic capacities C 101 , C 102 and C 103 which are connected in series, so compared to the case where the deep n-type well layer 143 and the n-type well layer 144 are not arranged, the impedance in a low-frequency region between the analog circuit 110 and the p-type semiconductor substrate 140 can be increased. In a high-frequency, the impedance can be relatively high. As a result, the analog circuit 110 can be less susceptible to the potential of the p-type semiconductor substrate 140 . SUMMARY OF THE INVENTION [0010] In a semiconductor element 100 shown in FIG. 30 , a seal ring 130 is arranged to prevent a decline in reliability of an analog circuit 110 and a digital circuit 120 caused by the entry of water or ions into them, and to prevent chipping occurring during a dicing process in which a wafer is divided along a scribe line region from reaching inside a chip. As shown in FIGS. 30 and 32A , the seal ring 130 is arranged in a portion surrounding the analog circuit 110 and the digital circuit 120 of a surface of the p-type semiconductor substrate 140 , and the seal ring 130 is formed by alternately laminating vias 131 and wiring layers 132 on a high-concentration p-type semiconductor region 133 formed on the surface of the p-type semiconductor substrate 140 . The side of the seal ring 130 is covered with an interlayer insulating film 141 formed on the p-type semiconductor substrate 140 , the top surfaces of the seal ring 130 and the interlayer insulating film 141 are covered with a passivation layer 142 . Moreover, an element separation insulating film 149 is arranged between the seal ring 130 and an element constituting the analog circuit 110 and the digital circuit 120 on the surface of the p-type semiconductor substrate 140 . [0011] As shown in FIG. 32B , the seal ring 130 is electrically connected to the p-type semiconductor substrate 140 directly below the seal ring 130 through a resistance R 101 . Therefore, noises generated in the digital circuit 120 propagate through not only the path path 1 but also the seal ring 130 as paths path 2 and path 3 . Moreover, the impedance of the seal ring 130 is lower than that of the p-type semiconductor substrate 140 , so it is more important to reduce noises (substrate noises) propagating through the paths path 2 and path 3 than through the path path 1 . [0012] Therefore, it can be considered that as shown in FIG. 35 , an n-type semiconductor region 134 is arranged on the surface of the p-type semiconductor substrate 140 instead of the p-type semiconductor region 133 , and as shown in FIG. 35 , a parasitic capacity C 104 is formed between the seal ring 130 and the p-type semiconductor substrate 140 . However, even in this case, a high-frequency signal is not attenuated by the parasitic capacity C 104 , and passes through. Moreover, it can be considered that as shown in FIG. 36 , an inner seal ring 410 is arranged on an edge portion of a semiconductor element 400 including an analog circuit and a digital circuit (both not shown), and an outer seal ring 420 is arranged outside the inner seal ring 410 . In this case, as shown in FIG. 37 , the inner seal ring 410 includes a p-type impurity diffused region 412 and an n-type impurity diffused region 413 on a surface layer of a p-type semiconductor substrate 411 . On a surface including the p-type impurity diffused region 412 and the n-type impurity diffused region 413 , a plurality of oxidized layers 414 are laminated at predetermined intervals, and vias 415 are formed in regions facing the p-type impurity diffused region 412 and the n-type impurity diffused region 413 of each oxidized layer 414 , and the via 415 at the bottom is in contact with the p-type infurity diffused region 412 and the n-type impurity diffused region 413 . Further, between the vias 415 , a metal layer 416 in contact with the vias 415 above and below the metal layer 416 is formed. On the other hand, as shown in FIG. 38 , the outer seal ring 420 is formed by alternately laminating oxidized layer 421 and metal layers 422 , and vias 423 are formed in a predetermined region of each oxidized layer 421 . Each via 423 except the via 423 at the bottom is in contact with the metal layers 422 above and below the via 423 , and the via 423 at the bottom is in contact with the metal layer 422 at the bottom and the p-type semiconductor substrate 411 (refer to US Patent Application Publication No. 2005/0110118). [0013] However, in the technique of US Patent Application Publication No. 2005/0110118, the inner seal ring 410 is in ohmic contact with the p-type semiconductor substrate 411 , and becomes a noise propagation path, so irrespective of whether the outer seal ring 420 is arranged or not, the analog circuit in the semiconductor element 400 is affected by the potential of the p-type semiconductor substrate 411 . [0014] In view of the foregoing, it is desirable to provide a semiconductor element capable of reducing noises of a circuit propagating to the other circuit through a seal ring, and a semiconductor device and a mounting board including the semiconductor element. [0015] According to an embodiment of the invention, there is provided a first semiconductor element in which a plurality of circuits are mounted on a surface of a semiconductor substrate. The first semiconductor element includes a ring-shaped seal ring surrounding the plurality of circuits; and wiring connecting between the seal ring and an external low-impedance node. [0016] In the first semiconductor element according to the embodiment of the invention, the wiring electrically connecting between the seal ring and the external low-impedance node is arranged. Thereby, a signal propagating in the seal ring flows into the external low-impedance node through the wiring. [0017] According to an embodiment of the invention, there is provided a second semiconductor element in which a plurality of circuits are mounted on a surface of a semiconductor substrate. The second semiconductor element includes a ring-shaped seal ring surrounding the plurality of circuits; a capacity element of which one end is connected to an external low-impedance node; and wiring connecting between the seal ring and the other end of the capacity element. [0018] In the second semiconductor element according to the embodiment of the invention, the wiring electrically connecting between the seal ring and the capacity element is arranged, and the capacity element is connected to the external low-impedance node. Thereby, a signal propagating in the seal ring flows into the capacity element through the wiring, and then flows into the external low-impedance node through the capacity element. [0019] According to an embodiment of the invention, there is provided a third semiconductor element in which a plurality of circuits are mounted on a surface of a first conductivity type semiconductor substrate. The third semiconductor element includes a ring-shaped seal ring surrounding the plurality of circuits; and a second conductivity type well layer separating a portion facing the seal ring of the semiconductor substrate from the other portion of the semiconductor substrate. [0020] In the third semiconductor element according to the embodiment of the invention, the second conductivity type well layer separating a portion facing the seal ring of the semiconductor substrate from the other portion of the semiconductor substrate is arranged. Thereby, parasitic capacities are formed at an interface of the well layer on a seal ring side and an interface of the well layer on a side opposite to the seal ring side, and the seal ring is electrically connected to the semiconductor substrate through the parasitic capacities which are connected in series. [0021] According to an embodiment of the invention, there is provided a fourth semiconductor element in which a plurality of circuits are mounted on a surface of the semiconductor substrate. The fourth semiconductor element includes a ring-shaped seal ring surrounding the plurality of circuits, and the seal ring has a shape meandering in a direction orthogonal to an extending direction. [0022] In the fourth semiconductor element according to the embodiment of the invention, the seal ring has a shape meandering in a direction orthogonal to an extending direction. The meandering shape functions as resistance for a high-frequency signal propagating in the seal ring. [0023] According to an embodiment of the invention, there is provided a fifth semiconductor element in which a plurality of circuits are mounted on a surface of a first conductivity type semiconductor substrate. The fifth semiconductor element includes a ring-shaped seal ring surrounding the plurality of circuits, and an insulating layer is formed between the semiconductor substrate and the seal ring. [0024] In the fifth semiconductor element according to the embodiment of the invention, the insulating layer is formed between the semiconductor substrate and the seal ring. Thereby, the seal ring is electrically separated from the semiconductor substrate by the insulating layer. [0025] According to an embodiment of the invention, there is provided a semiconductor device including at least one of the first to the fifth semiconductor elements. The semiconductor device includes a supporting body; the semiconductor element being formed on one surface of the supporting body; a lid being placed over the semiconductor element; and one or a plurality of terminals penetrating through the supporting body and being connected to the semiconductor element. [0026] According to an embodiment of the invention, there is provided a mounting board including: a supporting substrate; and the above-described semiconductor device being mounted on the supporting substrate. [0027] In the first semiconductor element according to the embodiment of the invention, and the semiconductor device and the mounting board including the first semiconductor element, the wiring electrically connecting between the seal ring and the external low-impedance node is formed, so noises generated in one circuit (for example, a digital circuit) can be emitted to the external low-impedance node through the wiring. Thereby, the noises of one circuit propagating to another circuit (for example, an analog circuit) through the seal ring can be reduced. [0028] In the second semiconductor element according to the embodiment of the invention, and the semiconductor device and the mounting board including the second semiconductor element, the wiring electrically connecting between the seal ring and the capacity element is formed, and the capacity element is connected to the external low-impedance node, so noises generated in one circuit can be emitted to the external low-impedance node through the wiring and the capacity element. Thereby, the noises of one circuit propagating to another circuit through the seal ring can be reduced. [0029] In the third semiconductor element according to the embodiment of the invention, and the semiconductor device and the mounting board including the third semiconductor element, the second conductivity-type well layer separating a portion facing the seal ring of the first conductivity-type semiconductor substrate from the other portion of the semiconductor substrate is formed, so compared to the case where such a well layer is not arranged, the impedance in a low-frequency region between one circuit and the semiconductor substrate can be increased. In a high-frequency, the impedance can be relatively high. Thereby, the noises of one circuit propagating to another circuit through the seal ring can be reduced. [0030] In the fourth semiconductor element according to the embodiment of the invention, and the semiconductor device and the mounting board including the fourth semiconductor element, the seal ring has a shape meandering in a direction orthogonal to an extending direction, so compared to the case where the seal ring does not have a meandering shape, the impedance in a low-frequency region between one circuit and the semiconductor substrate can be increased. In a high-frequency, the impedance can be relatively high. Thereby, the noises of one circuit propagating to another circuit through the seal ring can be reduced. [0031] In the fifth semiconductor element according to the embodiment of the invention, and the semiconductor device and the mounting board including the fifth semiconductor element, the insulating layer is formed between the semiconductor substrate and the seal ring, so compared to the case where such an insulating layer is not arranged, the impedance between one circuit and the semiconductor substrate can be increased. Thereby, the noises of one circuit propagating to another circuit through the seal ring can be reduced. [0032] Other and further objects, features and advantages of the invention will appear more fully from the following description. BRIEF DESCRIPTION OF THE DRAWINGS [0033] FIG. 1 is a plan view of a semiconductor element (an interlayer insulating film and a passivation layer are not shown) according to a first embodiment of the invention; [0034] FIG. 2 is a sectional view taken along a line A-A of FIG. 1 viewed from an arrow direction; [0035] FIG. 3 is a plan view for describing noise propagation paths in the semiconductor element shown in FIG. 1 ; [0036] FIG. 4 is a plan view of a semiconductor element (an interlayer insulating film and a passivation layer are not shown) according to a second embodiment of the invention; [0037] FIGS. 5A and 5B are sectional views taken along a line B-B of FIG. 4 viewed from an arrow direction; [0038] FIG. 6 is a sectional view of a semiconductor element according to a modification; [0039] FIG. 7 is a plan view of a semiconductor element (an interlayer insulating film and a passivation layer are not shown) according to a third embodiment of the invention; [0040] FIG. 8 is a sectional view taken along a line C-C of FIG. 7 viewed from an arrow direction; [0041] FIG. 9 is an equivalent circuit diagram of an example of the semiconductor element shown in FIG. 7 ; [0042] FIG. 10 is an equivalent circuit diagram of another example of the semiconductor element shown in FIG. 7 ; [0043] FIG. 11 is a plan view of a semiconductor element (an interlayer insulating film and a passivation layer are not shown) according to a modification; [0044] FIG. 12 is a sectional view taken along a line D-D of FIG. 11 viewed from an arrow direction; [0045] FIG. 13 is a sectional view of a semiconductor element according to another modification; [0046] FIG. 14 is a sectional view of a semiconductor element according to still another modification; [0047] FIG. 15 is a sectional view of a semiconductor element according to a further modification; [0048] FIG. 16 is a plan view of a semiconductor element (an interlayer insulating film and a passivation layer are not shown) according to a fourth embodiment of the invention; [0049] FIG. 17 is a sectional view taken along a line A-A of FIG. 16 viewed from an arrow direction; [0050] FIGS. 18A and 18B are sectional views of a semiconductor element according to a modification; [0051] FIGS. 19A and 19B are sectional views of a semiconductor element according to another modification; [0052] FIGS. 20A and 20B are sectional views of a semiconductor element according to another modification of each embodiment; [0053] FIG. 21 is a plot showing noise characteristics of semiconductor elements according to Examples 1 and 2 and Comparative Example 1; [0054] FIG. 22 is a plot showing noise characteristics of semiconductor elements according to Example 3 and Comparative Example 2; [0055] FIG. 23 is a plan view of the semiconductor element according to Example 2; [0056] FIG. 24 is a plot showing noise characteristics of semiconductor elements according to Example 4 and Comparative Example 1; [0057] FIG. 25 is a plot showing noise characteristics of semiconductor element according to Example 5 and Comparative Example 2; [0058] FIG. 26 is a plot showing noise characteristics of semiconductor elements according to Example 6 and Comparative Example 1; [0059] FIG. 27 is a plot showing noise characteristics of semiconductor element according to Example 7 and Comparative Example 2; [0060] FIG. 28 is a sectional view showing an example of a semiconductor device according to an application example; [0061] FIG. 29 is a perspective view showing an example of a mounting board according to another application example; [0062] FIG. 30 is a plan view of a semiconductor element (an interlayer insulating film and a passivation layer are not shown) in a related art; [0063] FIG. 31 is a sectional view taken along a line A-A of FIG. 30 viewed from an arrow direction; [0064] FIGS. 32A and 32B are sectional views taken along a line B-B of FIG. 30 viewed from an arrow direction; [0065] FIG. 33 is a plan view for describing noise propagation paths in the semiconductor element shown in FIG. 30 ; [0066] FIG. 34 is a sectional view of a semiconductor element in a related art according to a modification; [0067] FIG. 35 is a sectional view of a semiconductor element in a related art according to another modification; [0068] FIG. 36 is a plan view of a semiconductor element in a related art according to still another modification; [0069] FIG. 37 is a sectional view of FIG. 36 ; and [0070] FIG. 38 is a sectional view of FIG. 36 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0071] Preferred embodiments will be described in detail below referring to the accompanying drawings. First Embodiment [0072] FIG. 1 shows a plan view of a semiconductor element 1 according to a first embodiment of the invention. In FIG. 1 , an interlayer insulating film 43 and a passivation layer 44 (which will be described later) of the semiconductor element 1 are not shown. FIG. 2 shows a sectional view taken along a line A-A of FIG. 1 viewed from an arrow direction, and a state in which a resistance R 1 formed between a via 31 and a p-type semiconductor region 33 in a sectional portion, a parasitic capacity C 1 formed between a p-type semiconductor region 47 directly below th p-type semiconductor region 33 and a deep n-type well layer 41 , and a parasitic capacity C 2 formed between a p-type semiconductor region 48 directly below the deep n-type well layer 41 and the deep n-type well layer 41 are connected in series. The deep n-type well layer 41 is biased by a positive DC voltage to reduce C 1 and C 2 , and obtain the isolation between a seal ring 30 and a p-type semiconductor substrate 40 . [0073] As shown in FIG. 1 , the semiconductor element 1 includes an analog circuit 10 and a digital circuit 20 implemented on a p-type semiconductor substrate 40 . Although it is not shown, for example, the analog circuit 10 is electrically connected to the p-type semiconductor substrate 40 through a parasitic capacity formed between an n-type source region or an n-type drain region of a transistor included in the analog circuit 10 and the p-type semiconductor substrate 40 . Therefore, at a certain frequency or higher, the analog circuit 10 is coupled to the p-type semiconductor substrate 40 with low impedance, and the analog circuit 10 is susceptible to the potential of the p-type semiconductor substrate 40 . Therefore, it is preferable that the analog circuit 10 is arranged away from the digital circuit 20 which may be a noise source, and is arranged in a corner of a chip as shown in FIG. 1 . [0074] Moreover, in the semiconductor element 1 , as shown in FIGS. 1 and 2 , a seal ring 30 is arranged. The seal ring 30 is formed on a surface of an edge portion (a scribe line region in a wafer before cutting the semiconductor element 1 into a chip) of the p-type semiconductor substrate 40 , and has a ring shape surrounding the analog circuit 10 and the digital circuit 20 on the surface of the p-type semiconductor substrate 40 . Further, the seal ring 30 has a laminate configuration in which vias 31 and wiring layers 32 are alternately laminated on a high-concentration p-type semiconductor region 33 formed on the surface of the p-type semiconductor substrate 40 . Thereby, the seal ring 30 prevents a decline in reliability of the analog circuit 10 and the digital circuit 20 caused by the entry of water, ions or the like into them. Moreover, the seal ring 30 prevents chipping occurring during a dicing process in which a wafer is separated along the scribe line region from reaching inside a chip. [0075] The side of the seal ring 30 is covered with the interlayer insulating film 43 formed on the p-type semiconductor substrate 40 , the top surfaces of the seal ring 30 and the interlayer insulating film 43 are covered with the passivation layer 44 formed by laminating a SiO 2 layer 44 A and a polyimide layer 44 B in this order. [0076] Moreover, an element separation insulating film 49 is arranged between the seal ring 30 and an element constituting the analog circuit 10 and the digital circuit 20 on the surface of the p-type semiconductor substrate 40 . The element separation insulating film 49 is formed of, for example, LOCOS (local oxidation of silicon) or STI (Shallow Trench Isolation), and separates the seal ring 30 and the element constituting the analog circuit 10 and the digital circuit 20 from each other on the surface of the p-type semiconductor substrate 40 . [0077] Further, in the semiconductor element 1 , as shown in FIG. 2 , the deep n-type well layer 41 and the n-type well layer 42 are arranged. The deep n-type well layer 41 is arranged so as to face the bottom surface of the seal ring 30 , and has a ring shape. The n-type well layer 42 is arranged so as to come into contact with the seal ring 30 on an inner periphery and an outer periphery of the seal ring 30 and to be exposed to the surface of the p-type semiconductor substrate 40 , and has a ring shape. In other words, the bottom surface (the p-type semiconductor region 33 ) of the seal ring 30 is separated from the other portion of the p-type semiconductor substrate 40 by the deep n-type well layer 41 and the n-type well layer 42 . Thereby, as shown in FIG. 2 , the resistance R 1 is formed between the via 31 and the p-type semiconductor region 33 and 47 , the parasitic capacity C 1 is formed between the deep n-type well layer 41 and the p-type semiconductor region 47 , the parasitic capacity C 2 is formed between the deep n-type well layer 41 and the p-type semiconductor region 48 , and they are connected in series, so the seal ring 30 is electrically connected to the p-type semiconductor substrate 40 through the resistance R 1 , the parasitic capacity C 1 and the parasitic capacity C 2 which are connected in series. [0078] In the semiconductor element 1 according to the embodiment, when the analog circuit 10 and the digital circuit 20 are driven, various noises are generated from them. At this time, for example, in the case where while a high-frequency signal with a large amplitude flows in the digital circuit 20 , a high-frequency signal with a small amplitude of a few μV to a few mV flows in the analog circuit 10 , the possibility that noises generated in the digital circuit 20 exert an influence on the analog circuit 10 is increased. [0079] As shown in FIG. 3 , the noises generated in the digital circuit 20 propagate to the analog circuit 10 through the p-type semiconductor substrate 40 as a path path 1 , and propagate to the analog circuit 10 through the seal ring 30 as paths path 2 and path 3 ; however, typically the impedance of the seal ring 30 is lower than that of the p-type semiconductor substrate 40 . Therefore, as shown in FIG. 30 , in a semiconductor element 100 in a related art, noises generated in a digital circuit 120 propagate to an analog circuit 110 through paths path 2 and path 3 . [0080] On the other hand, in the semiconductor element 1 according to the embodiment, the deep n-type well layer 41 and the n-type well layer 42 are formed so as to separate the bottom surface (the p-type semiconductor region 33 ) of the seal ring 30 from the other portion of the p-type semiconductor substrate 40 , and the seal ring 30 is electrically connected to the p-type semiconductor substrate 40 through the resistance R 1 , the parasitic capacity C 1 and the parasitic capacity C 2 which are connected in series, so compared to the semiconductor element 100 in the related art in which the deep n-type well layer 41 and the n-type well layer 42 are not arranged, the impedance in a low-frequency region between the seal ring 30 and the p-type semiconductor substrate 40 is higher. In a high-frequency, the impedance can be relatively high. Thereby, even if noises generated in the digital circuit 20 propagate through the paths path 2 and path 3 , noises are attenuated by a high impedance between the seal ring 30 and the p-type semiconductor substrate 40 , so the influence of noises generated in the digital circuit 20 exerted on the potential of the p-type semiconductor substrate 40 directly below the analog circuit 10 can be reduced. As a result, the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 30 can be reduced. [0081] Moreover, in the embodiment, noises propagating through the paths path 2 and path 3 are attenuated by the deep n-type well layer 41 and the n-type well layer 42 before the noises propagate in the p-type semiconductor substrate 40 , so noises largely attenuated by a portion with a high impedance (the deep n-type well layer 41 and the n-type well layer 42 ) can be further attenuated until the noises reach the analog circuit 10 . Therefore, in the embodiment, compared to the case where like a semiconductor element in a related art, a deep n-type well layer 143 and a n-type well layer 144 are arranged directly below an analog circuit 110 , and noises propagating in a p-type semiconductor substrate 140 is attenuated in close vicinity to the analog circuit 110 (refer to FIGS. 23 and 27 ), noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 30 can be further reduced. Modification of First Embodiment [0082] In the above-described embodiment, the p-type semiconductor region 33 of a conductivity type equal to that of the p-type semiconductor substrate 40 is formed in the bottom of the seal ring 30 ; however, an n-type semiconductor region (not shown) may be formed in the bottom of the seal ring 30 . Thereby, a parasitic capacity is formed between the n-type semiconductor region and the p-type semiconductor region 47 , and is connected to the other parasitic capacities C 1 and C 2 in series, so a frequency band with high impedance between the seal ring 30 and the p-type semiconductor substrate 40 can be further expanded on a high frequency side than the case of the above-described embodiment. As a result, even in the case where a frequency band used in the analog circuit 10 is extremely high, the impedance between the seal ring 30 and the p-type semiconductor substrate 40 in the used frequency band can be increased, so high-frequency noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 30 can be reduced. Second Embodiment [0083] FIG. 4 shows a plan view of a semiconductor element 2 according to a second embodiment of the invention. In FIG. 4 , the interlayer insulating film 43 and the passivation layer 44 of the semiconductor element 2 are not shown. FIG. 5A shows a sectional view taken along a line B-B of FIG. 4 viewed from an arrow direction, and FIG. 5B shows the resistance R 1 formed between the via 31 and the p-type semiconductor region 33 in a sectional portion of FIG. 5A . [0084] The configuration of the semiconductor element 2 is distinguished from that in the above-described embodiment by the fact that the semiconductor element 2 includes a seal ring 50 formed by adding a meander section 34 to the components of the seal ring 30 in the above-described embodiment, and the deep n-type well layer 41 and the n-type well layer 42 in the above-described embodiment are not included. Therefore, configurations, functions and effects similar to those in the above-described embodiment will not be further described, and mainly differences from the above-described embodiment will be described below. [0085] As shown in FIG. 4 , the meander section 34 has a shape meandering in a direction orthogonal to an extending direction, and functions as high impedance path to high-frequency noises propagating in the seal ring 50 . In other words, in the embodiment, to increase the impedance of the paths path 2 and path 3 , the meander section 34 is used instead of the deep n-type well layer 41 and the n-type well layer 42 in the above-described embodiment. Thereby, even if noises generated in the digital circuit 20 propagate through the paths path 2 and path 3 , the noises are attenuated by high impedance of the meander section 34 , so the influence of the noises generated in the digital circuit 20 exerted on the potential of the p-type semiconductor substrate 40 directly below the analog circuit 10 can be reduced. As a result, the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 30 can be reduced. [0086] In particular, in the case where the meander section 34 is arranged close to the digital circuit 20 which is a noise source, the meander section 34 is positioned away from the analog circuit 10 which a high-impedance portion protects from noises, so noises largely attenuated in the high-impedance portion can be further attenuated until the noises reach the analog circuit 10 . Thereby, the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 30 can be further reduced. Modification of Second Embodiment [0087] In the above-described embodiment, the meander section 34 with high impedance is arranged in the middle of each of the paths path 2 and path 3 ; however, as in the case of a semiconductor element 3 shown in FIG. 6 , the deep n-type well layer 41 and the n-type well layer 42 in the first embodiment may be further arranged. Thereby, two high-impedance portions are connected in series in the middle of each of the paths path 2 and path 3 , so the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 30 can be further reduced. Third Embodiment [0088] FIG. 7 shows a plan view of a semiconductor element 4 according to a third embodiment of the invention. In FIG. 7 , the interlayer insulating film 43 and the passivation layer 44 of the semiconductor element 4 are not shown. FIG. 8 shows a sectional view taken along a line C-C of FIG. 7 viewed from an arrow direction, and a resistance R 2 formed between the via 31 or a via 71 and the p-type semiconductor region 35 in a sectional portion. [0089] The configuration of the semiconductor element 4 is distinguished from that in the first embodiment by the fact that the semiconductor element 4 includes a seal ring 60 including a p-type semiconductor region 35 formed by extending a portion of the high doping concentration p-type semiconductor region 33 included in the seal ring 30 in the first embodiment to a layout pattern region (a region on which the analog circuit 10 or the digital circuit 20 is arranged) inside a chip and a noise isolator 70 connected to the seal ring 60 , and does not include the deep n-type well layer 41 and the n-type well layer 42 in the first embodiment. Therefore, configurations, functions and effects similar to those in the first embodiment will not be further described, and mainly differences from the first embodiment will be described below. [0090] As shown in FIG. 8 , the p-type semiconductor region 35 includes a ring-shaped portion formed in a region facing the via 31 of the p-type semiconductor substrate 40 and a portion extending from a part of the ring-shaped portion to the layout pattern region inside the chip. The noised isolator 70 has a laminate configuration in which vias 71 and wiring layers 72 are alternately laminated on a surface of a portion extending to the layout pattern region in the p-type semiconductor region 35 , and the wiring layer 72 is formed in the uppermost layer of the laminate configuration. A pad 74 is connected to the wiring layer 72 in the uppermost layer through a via 73 . The via 73 and the pad 74 are formed in a SiO 2 layer 44 A, and a portion of the pad 74 is exposed to outside. [0091] The exposed portion of the pad 74 is arranged so as to be electrically connected to a low-impedance node (not shown) arranged outside the semiconductor element 4 , or to a capacity element arranged in the semiconductor element 4 , for example, a decoupling capacitor, a MIM (Metal-Insulator-Metal) capacitor, a comb-type capacitor or a capacitor arranged in an IPD (Integrated Passive Device). [0092] In the case where the exposed portion of the pad 74 is electrically connected to the outside low-impedance node, the path path 2 or path 3 can be represented by an equivalent circuit shown in FIG. 9 . In the equivalent circuit, the digital circuit 20 is represented as a noise source S and digital circuit impedance Zd: impedance from the digital circuit ground to the off chip ground, the seal ring 60 is represented as seal ring impedance Zs, the analog circuit 10 is represented as analog circuit impedance Za: impedance from the analog circuit ground to the off chip ground, the noise isolator 70 is presented as noise isolator impedance Zn, a path between the digital circuit 20 and the seal ring 60 in the p-type semiconductor substrate 40 is represented as a substrate resistance R 1 , and a path between the analog circuit 10 and the seal ring 60 in the p-type semiconductor substrate 40 is represented as a substrate resistance R 2 . Then, Zd, R 1 , Zs, R 2 and Za are connected in series between the noise source S and the ground, and Zn is connected between a portion separating Zs into two impedances Zs 1 and Zs 2 and the ground. In other words, the analog circuit 10 and the noise isolator 70 are connected in parallel, so in this case, it is necessary for Zn to be smaller than the total of Zs 2 , R 2 and Za which are connected in series. [0093] Moreover, in the case where the exposed portion of the pad 74 is electrically connected to the capacity element arranged in the semiconductor element 4 , the path path 2 or path 3 can be represented by an equivalent circuit shown in FIG. 10 . In the equivalent circuit, Zd, R 1 , Zs, R 2 and Za between the noise source S and the ground are connected in series, and Zn and a capacity Cd of the capacity element are connected between a portion separating Zs into two impedances Zs 1 and Zs 2 and the ground. In other words, the analog circuit 10 is connected to the noise isolator 70 and the capacity element in parallel, so in this case, it is necessary for the total impedance of Zn and Cd to be smaller than the total of Zs 2 , R 2 and Za which are connected in series. [0094] In the first embodiment, the deep n-type well layer 41 and the n-type well layer 42 are arranged to increase the impedances of the paths path 2 and path 3 ; however, in the embodiment, the noise isolator 70 with lower impedance than the impedance of a portion in parallel to the noise isolator 70 of the paths path 2 and path 3 is arranged to induce noises generated in the digital circuit 20 to the noise isolator 70 . Thereby, even if the noises generated in the digital circuit 20 propagate through the paths path 2 and path 3 , the noises are induced to the noise isolator 70 , so the propagation of the noises to the analog circuit 10 is prevented, and the influence of the noises generated in the digital circuit 20 exerted on the potential of the p-type semiconductor substrate 40 directly below the analog circuit 10 can be reduced. As a result, the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 60 can be reduced. [0095] In particular, in the case where a connecting portion between the seal ring 60 and the noise isolator 70 is arranged close to the digital circuit 20 which is a noise source, a portion in which noises are induced to the noise isolator is positioned away from the analog circuit 10 which is protected from noises, so noises induced by the noise isolator 70 to be largely attenuated can be further attenuated until the noises reach the analog circuit 10 . Thereby, the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 60 can be further reduced. [0096] Moreover, in the embodiment, the noise isolator 70 is arranged in a layout pattern region which can be freely designed by a designer designing the analog circuit 10 or the digital circuit 20 , so the designer can freely design the noise isolator 70 satisfying a condition of the above-described equivalent circuit. Modification of Third Embodiment [0097] In the above-described embodiment, the noise isolator 70 with low impedance is arranged in parallel in the middle of each of the paths path 2 and path 3 : however, as shown in a semiconductor element 5 of FIGS. 11 and 12 (a sectional view taken along a line D-D of FIG. 11 viewed from an arrow direction), the meander section 34 in the second embodiment may be further arranged to form a seal ring 80 . In FIG. 11 , the case where the noise isolator 70 is arranged closer to the digital circuit 20 than the meander section 34 is shown as an example; however, either the noise isolator 70 or the meander section 34 may be arranged closer to the digital circuit 20 . Thereby, one high-impedance portion is inserted in series in the middle of each of the paths path 2 and path 3 , and the noise isolator 70 with low impedance is connected in parallel, so the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 80 can be further reduced. [0098] Moreover, as shown in a semiconductor element 6 shown in FIG. 13 , as in the case of the first embodiment, the deep n-type well layer 41 and the n-type well layer 42 may be arranged in the semiconductor element 4 in the third embodiment. In this case, not only the seal ring 60 but also the noise isolator 70 is separated from the other portion of the p-type semiconductor substrate 40 by the deep n-type well layer 41 and the n-type well layer 42 . Thereby, one high impedance portion is inserted in series in the middle of each of the paths path 2 and path 3 , and the noise isolator 70 with low impedance is connected in parallel, so the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 60 can be further reduced. [0099] Further, as shown in a semiconductor element 7 in FIG. 14 , the semiconductor element 6 in FIG. 13 may include a seal ring 80 formed by arranging the meander section 34 in the second embodiment. Thereby, two high-impedance portions are inserted in series in the middle of each of the paths path 2 and path 3 , and the noise isolator 70 with low impedance is connected in parallel, so the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 80 can be further reduced. [0100] In the third embodiment, the seal ring and the noise isolator are separately formed; however, a portion of the seal ring may be commonly used as a portion of the noise isolator. For example, as shown in a semiconductor element 8 in FIG. 15 , a noise isolator 270 commonly uses the via 31 and the wiring layer 32 of a seal ring 230 as a via 71 and a wiring layer 72 , and the wiring layer 32 extending from a scribe line to a layout pattern in the uppermost layer is commonly used as a wiring layer 232 , and the noise isolator 270 includes the via 73 and the pad 74 connected to a surface on a side closer to the layout pattern of the wiring layer 232 on it own. In such a case, the noise isolator 270 is connected to the seal ring 230 through the wiring layer 232 , so compared to the above-described embodiment in which the noise isolator 70 is connected to the seal ring 80 through the p-type semiconductor region 35 , the noise isolator 270 can be connected to the seal ring 230 with low resistance. As a result, the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 230 can be further reduced. [0101] In the semiconductor element 8 , the p-type semiconductor region 33 of the seal ring 230 is not used for electrical connection between the seal ring 230 and the noise isolator 270 , so the p-type semiconductor region 33 may be removed. Fourth Embodiment [0102] FIG. 16 shows a plan view of a semiconductor element 9 according to a fourth embodiment of the invention. In FIG. 16 , the interlayer insulating film 43 and the passivation layer 44 of the semiconductor element 9 are not shown. FIG. 17 shows a sectional view taken along a line A-A of FIG. 16 viewed from an arrow direction, and a parasitic capacity C 3 formed between the via 31 and the p-type semiconductor region 35 in a sectional portion. [0103] The configuration of the semiconductor element 9 is distinguished from that in the first embodiment by the fact that the semiconductor element 9 includes a seal ring 240 on the p-type semiconductor substrate 40 , and the p-type semiconductor region 33 , the deep n-type well layer 41 and the n-type well layer 42 are not included. Therefore, configurations, functions and effects similar to those in the first embodiment will not be further described, and mainly differences from the first embodiment will be described below. [0104] The seal ring 240 is formed on a surface of an edge portion (a scribe line region on a wafer before cutting the semiconductor element 1 into a chip) of the p-type semiconductor substrate 40 , and has a ring shape surrounding the analog circuit 10 and the digital circuit 20 on the surface of the p-type semiconductor substrate 40 . Moreover, the seal ring 240 has a laminate configuration in which vias 31 and wiring layers 32 are alternately laminated on a polysilicon film 36 formed on the surface of the p-type semiconductor substrate 40 . Thereby, the seal ring 240 prevents a decline in reliability of the analog circuit 10 and the digital circuit 20 caused by the entry of water, ions or the like into them. Moreover, the seal ring 240 prevents chipping occurring during a dicing process in which the wafer is separated along the scribe line region from reaching inside the chip. The polysilicon film 36 can function as an etching stop layer when forming a hole for arranging the vias 31 and the wiring layers 32 in a manufacturing process. [0105] Moreover, the seal ring 240 comes into contact with the p-type semiconductor substrate 40 through the polysilicon film 36 and the element separation insulating film 49 . Therefore, as shown in FIG. 17 , a capacity C 3 is formed by a capacitor formed by the vias 31 , the polysilicon film 36 and the p-type semiconductor substrate 40 . In this case, the polysilicon film 36 can be formed at the same time when a gate electrode of a CMOS is formed, and is formed of LOCOS (local oxidation of silicon) or STI (Shallow Trench Isolation), and has a sufficient thickness. Therefore, the magnitude of the capacity C 3 is extremely small, and the impedance relative to high frequency is high, so even if noises generated in the digital circuit 20 propagates through the paths path 2 and path 3 , the influence exerted on the potential of the p-type semiconductor substrate 40 can be reduced. As a result, the noises of the digital circuit 20 propagating the analog circuit 10 through the seal ring 240 can be reduced. Modification of Fourth Embodiment [0106] In the above-described embodiment, the polysilicon film 36 and the element separation insulating film 49 are arranged in the lowermost portion of the seal ring 240 , and the seal ring 240 is separated from the p-type semiconductor substrate 40 ; however, as shown in FIGS. 18A and 18B , when the interlayer insulating film 43 is arranged instead of the polysilicon film 36 and the wiring layer 32 and the via 31 which are formed adjacent to the polysilicon film 36 , the seal ring 240 can be separated from the p-type semiconductor substrate 40 . [0107] Moreover, a multilayer semiconductor layer formed by alternately laminating two or more semiconductor layers of different conductivity types may be formed in a region facing the seal ring 240 of a surface of the p-type semiconductor substrate 40 . For example, as shown in FIG. 19A , in the case where a p-type semiconductor layer 52 and an n-type semiconductor layer 51 are formed in this order from the seal ring 240 on the surface of the p-type semiconductor substrate 40 , as shown in FIG. 19B , in addition to the capacity C 3 , a parasitic capacity C 4 is formed by pn junction formed at an interface between the p-type semiconductor layer 52 and the n-type semiconductor layer 51 , and a parasitic capacity C 5 is further formed by pn junction formed at an interface between the n-type semiconductor layer 51 and the p-type semiconductor substrate 40 , and the parasitic capacities C 4 and C 5 are connected to the capacity C 3 in series. Thereby, the magnitude of a capacity between the p-type semiconductor substrate 40 and the seal ring 240 can be extremely small, and the impedance relative to high frequency can be increased, so even if noises generated in the digital circuit 20 propagate through the paths path 2 and path 3 , the influence exerted on the potential of the p-type semiconductor substrate 40 can be reduced. As a result, the noises of the digital circuit 20 propagating to the analog circuit 10 through the seal ring 240 can be reduced. Modifications of Above-Described Embodiments and Modifications [0108] In the above-described embodiments and modifications, to reduce noises propagating through the paths path 2 and path 3 (refer to FIGS. 3 , 4 , 7 , 11 and 16 ), various measures are taken against the paths path 2 and path 3 , and in addition to this, to reduce noises propagating through the paths path 1 , path 2 and path 3 , in close vicinity to the analog circuit 10 , for example, as shown in FIG. 20A (a sectional view of a portion around the analog circuit 10 of the semiconductor element), a deep n-type well layer 45 and an n-type well layer 46 which separate the analog circuit 10 from the other portion of the p-type semiconductor substrate 40 may be arranged. Thereby, for example, as shown in FIG. 20B , a parasitic capacity C 6 is formed at an interface between the n-type source region 11 or the n-type drain region 12 of the transistor included in the analog circuit 10 and the p-type semiconductor substrate 40 , and a parasitic capacity C 7 is formed at an interface between the deep n-type well layer 45 and the n-type well layer 46 on a side closer to the analog circuit 10 , and a parasitic capacity C 8 is formed at an interface between the deep n-type well layer 45 and the n-type well layer 46 on a side opposite to the side closer to the analog circuit 10 . Thereby, the analog circuit 10 is electrically connected to the p-type semiconductor substrate 40 through the parasitic capacities C 6 , C 7 and C 8 which are connected in series, so compared to the case where the deep n-type well layer 45 and the n-type well layer 46 are not arranged, the impedance in a high-frequency region between the analog circuit 10 and the p-type semiconductor substrate 40 can be increased. As a result, the noises of the digital circuit 20 propagating to the analog circuit 10 through the paths path 1 , path 2 , and path 3 can be further reduced. EXAMPLES [0109] FIGS. 21 , 22 , 24 to 27 show examples of results of analyzing the influence of noises generated in the digital circuit 20 on the analog circuit 10 . A dashed-dotted line in FIG. 21 indicates an example of the result of Example 1, a solid line in FIG. 21 indicates an example of the result of Example 2, a solid line in FIG. 22 indicates an example of the result of Example 3, a solid line in FIG. 24 indicates an example of the result of Example 4, a solid line in FIG. 25 indicates an example of the result of Example 5, a solid line in FIG. 26 indicates an example of the result of Example 6, and a solid line in FIG. 27 indicates an example of the result of Example 7. Moreover, broken lines in FIGS. 21 , 24 and 26 indicate an example of the result of Comparative Example 1, and broken lines in FIGS. 22 , 25 and 27 indicate an example of the result of Comparative Example 2. [0110] Example 1 is a specific example of the semiconductor element 4 according to the above-described embodiment in which the noise isolator 70 is arranged closer to the analog circuit 10 (refer to FIG. 23 ). Example 2 is a specific example of the semiconductor element 4 in which the noise isolator 70 is arranged closer to the digital circuit 20 (refer to FIG. 7 ). Example 3 is a specific example of the semiconductor element 4 with the configuration of Example 2 in which the deep n-type well layer 45 and the n-type well layer 46 are arranged directly below the analog circuit 10 as shown in FIG. 20 . Example 4 is a specific example of the semiconductor element 1 according to the above-described embodiment. Example 5 is a specific example of the semiconductor element 1 with the configuration of Example 4 in which the deep n-type well layer 45 and the n-type well layer 46 are arranged directly below the analog circuit 10 as shown in FIG. 20 . Example 6 is a specific example of the semiconductor element 2 according to the above-described embodiment. Example 7 is a specific example of the semiconductor element 2 with the configuration of Example 6 in which the deep n-type well layer 45 and the n-type well layer 46 are arranged directly below the analog circuit 10 as shown in FIG. 20 . Comparative Example 1 is a specific example of the semiconductor element 100 shown in FIGS. 28 to 30 which does not take the measures against noises in the case of the above-described examples. Comparative Example 2 is a specific example of the semiconductor element with the configuration of Comparative Example 1 in which the deep n-type well layer 143 and the n-type well layer 144 are arranged directly below the analog circuit 110 as shown in FIG. 34 . [0111] It was obvious from FIG. 21 that in Examples 1 and 2, compared to Comparative Example 1 in which the noise isolator was not arranged in the seal ring, the noise level was extremely lower. It was considered that it was because in Examples 1 and 2, while the inductance per one side of the seal ring 60 was 3 nH, the inductance of the noise isolator 70 was as low as 1 nH, so the impedance in the noise frequency band of the noise isolator 70 was smaller than the impedance of a path on the analog circuit 10 side from a connecting point between the noise isolator 70 and the seal ring 60 in the paths path 2 and path 3 of noises propagating from the digital circuit 20 to the analog circuit 10 through the seal ring 60 , so the noises of the digital circuit 20 propagating to the analog circuit 10 through the paths path 2 and path 3 could be effectively induced to the noise isolator 70 . Thereby, it was found out that when the noise isolator 70 was connected to the seal ring 60 , the noises of the digital circuit 20 propagating to the analog circuit 10 through the paths path 2 and path 3 could be effectively reduced. [0112] Moreover, it was found out that in Example 2, compared to Example 1, the noises were further reduced. It was considered that it was because when the noise isolator 70 was arranged closer to the digital circuit 20 which was a noise source, the impedance of a path on the analog circuit 10 side from a connecting point between the noise isolator 70 and the seal ring 60 in the paths path 2 and path 3 of noises propagating from the digital circuit 20 to the analog circuit 10 through the seal ring 60 was increased, so the inductance of the noise isolator 70 was relatively reduced. Thereby, it was found out that when the noise isolator 70 was arranged closer to the digital circuit 20 , the noises could be reduced more effectively. [0113] It was obvious from FIG. 22 that in Example 3, compared to Comparative Example 2 in which the noise isolator was not arranged in the seal ring, the noise level was extremely lower. It was considered that since there was a large difference between the results, connecting the noise isolator 70 to the seal ring 60 was extremely effective to reduce noises. Thereby, it was found out that when the noise isolator 70 was connected to the seal ring 60 in addition to arranging the deep n-type well layer 45 and the n-type well layer 46 directly below the analog circuit 10 , the noises of the digital circuit 20 propagating to the analog circuit 10 could be effectively reduced. [0114] It was obvious from FIG. 24 that in Example 4, compared to Comparative Example 1 in which the deep n-type well layer and the n-type well layer were not arranged directly below the seal ring, the noise level was substantially lower. Thereby, it was found out that when the deep n-type well layer 41 and the n-type well layer 42 were arranged directly below the seal ring 30 , the noises of the digital circuit 20 propagating to the analog circuit 10 through the paths path 2 and path 3 could be effectively reduced. [0115] Moreover, it was obvious from FIG. 25 that in Example 5, compared to Comparative Example 2 in which the deep n-type well layer and the n-type well layer were not arranged directly below the seal ring, the noise level was slightly lower. It was considered that it was because in Example 5, noises propagating through the paths path 2 and path 3 were attenuated by the deep n-type well layer 41 and the n-type well layer 42 before the noises propagated in the p-type semiconductor substrate 40 , so the noises largely attenuated by a high-impedance portion (the deep n-type well layer 41 and the n-type well layer 42 ) were further attenuated until the noises reached the analog circuit 10 . Thereby, it was found out that when the deep n-type well layer 41 and the n-type well layer 42 were arranged directly below the seal ring 30 in addition to arranging the deep n-type well layer 45 and the n-type well layer 46 directly below the analog circuit 10 , the noises of the digital circuit 20 propagating to the analog circuit 10 through the paths path 2 and path 3 could be effectively reduced. [0116] It was obvious from FIG. 26 that in Example 6, compared to Comparative Example 1 in which the meander section was not arranged in the seal ring, the noise level was slightly lower. Thereby, it was found out that when the meander section 34 was arranged in the seal ring 50 , the noises of the digital circuit 20 propagating to the analog circuit 10 through the paths path 2 and path 3 could be effectively reduced. [0117] Moreover, it was obvious from FIG. 27 that in Example 7, compared to Comparative Example 2 in which the meander section was not arranged in the seal ring, the noise level was slightly lower. It was considered that it was because in Example 7, the noises propagating through the paths path 2 and path 3 were attenuated by the meander section 34 before the noise propagated in the p-type semiconductor substrate 40 , so the noises largely attenuated by a high-impedance portion (the meander section 34 ) were further attenuated until the noises reached the analog circuit 10 . Thereby, it was found out that when the meander section 34 was arranged in the seal ring 50 in addition to arranging the deep n-type well layer 45 and the n-type well layer 46 directly below the analog circuit 10 , the noises of the digital circuit 20 propagating to the analog circuit 10 through the paths path 2 and path 3 could be effectively reduced. Applications [0118] Each of the semiconductor elements according to the above-descried embodiments and modifications is applicable to, for example, a semiconductor device 2 shown in FIGS. 28 and 29 or a mounting board 3 on which the semiconductor device 2 is mounted. In this case, the semiconductor device 2 includes, for example, the semiconductor element 1 , a supporting substrate 301 fixing the semiconductor element 1 , a lid body 302 which is placed over the semiconductor element 1 and protects the semiconductor element 1 from outside, and a terminal 303 which penetrates through the supporting substrate 301 , and is exposed to the back surface of the supporting substrate and electrically connected to the semiconductor element 1 . Moreover, the mounting board 3 includes the semiconductor device 2 and a printed circuit board 4 on which the semiconductor device 2 and other various devices are mounted. [0119] In the semiconductor device 2 and the mounting board 3 in the application examples, for example, the semiconductor element 1 is driven by receiving power supply from a power source (not shown) connected to the mounting board 3 from the terminal 303 , and a response to a signal inputted from the terminal 303 can be outputted from the terminal 303 . At this time, in the semiconductor device 2 , the noises of the digital circuit 20 propagating to the analog circuit 10 are effectively reduced in the semiconductor element 1 , so signal processing can be performed with little influence of the noises of the digital circuit 20 . [0120] Although the present invention is described referring to the embodiments, the modifications and the examples, the invention is not limited to them, and can be variously modified. [0121] For example, in the above-described embodiments and the like, the case where the p-type semiconductor substrate 40 is used as a common substrate is described; however, the invention is applicable to the case where an n-type semiconductor substrate is used as a common substrate. However, in this case, the conductivity type described in the above-described embodiments and the like changes from p-type to n-type, and vice versa. [0122] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

A semiconductor element capable of reducing noises of a circuit propagating to another circuit through a seal ring is provided. A semiconductor element includes, on a surface of a semiconductor substrate: a plurality of circuits; a ring-shaped seal ring surrounding the plurality of circuits; and wiring connecting between the seal ring and an external low-impedance node.

BACKGROUND [0001] During the image forming process, inefficiencies from the photoconductive member to the media create waste toner. This may include toner that has been applied to a photoconductive member but not transferred to a media sheet or belt, or toner that is applied to a belt but not transferred to the media sheet. This waste toner should be removed and transported away to prevent print quality problems. The waste toner may be stored at a variety of locations. Previous devices have stored the waste toner in an area adjacent to image formation area. Other designs transport the waste toner from the image formation area to a remote area within the device. [0002] Regardless of the location of the waste toner reservoir, the waste toner is conveyed from the location where the waste toner is removed from the photoconductive member or belt to the waste toner reservoir. The path for moving the waste toner is usually an enclosed conduit having a reduced cross-sectional size. The cross-sectional size of the path is often kept as small as possible in an attempt to keep the overall size of the image forming device to a minimum. The physical properties of the waste toner and the pathway have caused issues in the ability to move the waste toner to the waste toner reservoir. In one instance, the waste toner accumulates within the pathway and forms a bridge that blocks additional toner from being transported through the pathway. Instead of passing through the pathway, the waste toner backs up and may ultimately leak into the image formation area. SUMMARY [0003] The present invention relates to embodiments for a waste toner auger for use in an image forming device. The auger is positioned within a channel to move toner within the image forming device. The auger has an axis of rotation and at least one offset section. The offset section forms a sweep envelope that extends outward from the axis of rotation. The auger may be positioned within the channel for the offset to contact the channel. Contact may cause a vibratory force that prevents the toner from clogging and bridging within the channel. BRIEF DESCRIPTION OF THE DRAWINGS [0004] FIG. 1 is a schematic view of an image forming device according to one embodiment of the present invention; [0005] FIG. 2 is a partial perspective view illustrating elements of the waste toner system according to one embodiment of the present invention; [0006] FIG. 3 is a partial cut-away perspective view illustrating a section of the waste toner system according to one embodiment of the present invention; [0007] FIG. 4 is a schematic view illustrating a waste toner auger according to one embodiment of the present invention; [0008] FIG. 5 is a cross-sectional view illustrating an auger within a housing according to one embodiment of the present invention; [0009] FIG. 6 is a schematic view illustrating a waste toner auger according to one embodiment of the present invention; [0010] FIG. 7 is a schematic view illustrating a waste toner auger according to one embodiment of the present invention; [0011] FIG. 8 is a partial cut-away perspective view illustrating a section of the waste toner system according to one embodiment of the present invention; and [0012] FIG. 9 is a cross-sectional view illustrating an auger within a housing according to one embodiment of the present invention. DETAILED DESCRIPTION [0013] For purposes of explanation of the basics of image formation, FIG. 1 illustrates the general elements of one embodiment of an image forming device 10 . The representative image forming device 10 comprises a main body 12 with one or more image forming units 100 . Color image forming devices typically include four image forming units 100 for printing with cyan, magenta, yellow, and black toner to produce a four-color image on the media sheet. In this embodiment, each image forming unit 100 comprises a developer section 40 and a photoconductive section 50 . Toner is originally stored within the developer section 40 and is ultimately moved to a photoconductive member 51 within the photoconductive section 50 . The toner image on the photoconductive member 51 is then transferred to a media sheet moving along a transport belt 20 . [0014] Following the image forming process, residual waste toner is moved from the photoconductive section 50 through a waste toner system as illustrated in FIG. 2 . The waste toner system comprises a toner chute 60 and a waste toner reservoir 83 . For simplicity, FIG. 2 illustrates a single image forming unit 100 attached to the toner chute 60 . For a color image forming device, three additional image forming units 100 may also be attached to the toner chute 60 . The waste toner from the photoconductive section 50 is moved into the toner chute 60 and ultimately deposited within the reservoir 83 . Each of the photoconductive sections 50 and toner chute 60 include waste toner pathways that may experience toner bridging and clogging during toner movement. This bridging and clogging may prevent the waste toner from ultimately reaching the waste toner reservoir 83 . [0015] FIG. 3 illustrates an interior portion of the photoconductive section 50 . A cleaner blade 53 removes residual toner from the photoconductive drum (not shown) and deposits the residual toner into an interior channel 61 of a cleaner housing 62 . An auger 54 is positioned within the interior channel 61 to move the waste toner along the interior channel 61 and through a port 64 into the toner chute 60 . The auger 54 may be affixed at one end to a drive gear 66 . The drive gear 66 is driven by a motor within the main body 12 to rotate the auger 54 and moves the waste toner towards the port 64 and into the toner chute 60 . [0016] FIG. 4 illustrates one embodiment of an auger 54 used for moving the waste toner. The auger 54 has an elongated length with a helical configuration. In this embodiment, the auger 54 has a curved shape that is offset from a centerline C of an axis of rotation. The offset O varies along the length from no offset at the ends 58 , 59 , to a maximum offset at a central area. The amount of offset may be measured from the centerline C to a variety of locations on the auger (e.g., center, outer edge, inner edge). During rotation, the auger 54 has a sweep envelope that varies along the axial length of the auger as a function of the amount of offset O. In the embodiment of FIG. 4 , the sweep envelope is two times the amount of offset O. In one embodiment, the centerline C of the auger 54 and the channel are both substantially linear. [0017] The auger 54 rotates within the interior channel 61 to move toner along the length of the photoconductive section 50 . FIG. 5 is a cross-sectional view cut along line 5 - 5 of FIG. 3 illustrating the interior channel 61 and auger 54 . The interior channel 61 is formed by sidewalls 62 and may include an opening 69 to receive the waste toner that is removed from the photoconductive member 51 . In this embodiment, the auger 54 is positioned for the offset to contact the interior channel 61 at two locations. The other axial sections of the auger 54 have smaller sweep envelopes and therefore do not contact the interior channel 61 . [0018] The position of the auger 54 and the offset O brings the central area of the auger 54 into contact against the sidewalls 62 during rotation. This contact may, even if only momentarily, interrupt the rotation of the waste toner auger 54 . During this interruption, drive gear 66 may continue to apply a rotational force to the auger 54 . The applied rotational force may build a mechanical force within the waste toner auger 54 . This force may be released when the built force overcomes any friction between the waste toner auger 54 and the interior channel 61 . Upon release of the built force, the auger 54 may rotationally accelerate, and then may resume normal rotation speed. This vibratory force, in conjunction with the rotating auger 54 , causes the accumulated waste toner to continually break apart, preventing bridging and clogging of the waste toner as it is transported along the waste toner conveyance path. [0019] During a single revolution of the waste toner auger 54 there may be numerous contact, force build and force release cycles along an axial section of the interior channel 61 . The embodiment of FIG. 5 includes two points of contact (i.e., the left and lower sidewalls 62 as viewed in FIG. 5 ). Further, the auger 54 may be shaped for one or more axial contact points along the length. The embodiment of FIG. 5 illustrates one axial contact, although more points may be used depending upon the application. [0020] The auger 54 may have a variety of different shapes. FIG. 6 illustrates another embodiment having a stepped configuration with an offset O from the centerline C that increases towards a central area. FIG. 7 illustrates another embodiment having a variety of axial sections that are offset from the centerline C. Axial sections 53 , 54 , and 55 are each sized to contact the interior channel 61 . Offset sections 53 , and 55 are offset a greater amount than offset section 54 . Sections 53 , 55 create a greater amount of vibration during rotation than section 54 that causes a smaller amount of vibration. In other embodiments, each of the offsets may be the same, or each may be different depending upon the desired results. The shapes of the offsets may also vary as necessary. Offsets having an elongated surface, such as sections 53 and 55 , may impart a greater vibratory force during rotation than a smaller offset surface such as section 54 . The ends 58 , 59 of the auger 54 may both be positioned on the centerline C of the axis of rotation as illustrated in the embodiment of FIGS. 4 and 5 , or one or both ends may be offset from the centerline C as illustrated in FIG. 7 . [0021] The interior channel 61 may have a variety of shapes. In the embodiment of FIG. 5 , the interior channel 61 has a substantially rectangular shape. In another embodiment, the interior channel 61 has an oval or circular shape. In one embodiment the interior channels 61 , 63 are elongated with nearly parallel sides. In one embodiment the interior channels 61 , 63 may be constructed with various cross-sectional shapes, including square, flat, tapered, and other shapes known to those skilled in the art. [0022] FIG. 8 illustrates another application for placing the auger 54 within the toner chute 60 . In this embodiment, the auger 54 is vertically positioned within the chute 60 and uses gravity for further assistance to move the waste toner. However, testing has indicated that the waste toner may clog and bridge within the vertical chute 60 . The auger 54 of the present invention is necessary to reduce or eliminate this problem. [0023] The auger 54 may be constructed in various shapes and sizes of wire or solid shafts having a non-linear shape. In one embodiment the waste toner auger 54 may be formed from a helically-curved wire. In one embodiment the waste toner auger 54 may be a solid shaft helical screw having pitched blades or fins. In one embodiment the waste toner auger 54 may be constructed with various cross-sectional shapes including square, flat, tapered, etc. The auger 54 may be constructed of a deformable material. This causes the cross-sectional shape of the offset to deform during contact with the interior channel 61 . The shape then returns towards the normal shape after the offset moves beyond the contact. [0024] The auger 54 may be positioned at a variety of locations within the interior channels 61 , 63 . In one embodiment, the auger 54 is centered within the channels. In another embodiment as illustrated in FIG. 9 , the auger 54 is positioned away from a center of the channel. [0025] The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Embodiments for a toner auger for use in an image forming device. The image forming device includes a channel through which toner is moved. The auger is positioned within the channel and has an axis of rotation and at least one offset section extending radially outward from the axis of rotation. The offset section forms a sweep envelope that extends outward from the axis of rotation. The auger may be positioned within the channel for the offset to contact the channel. Contact may cause a vibratory force that prevents the toner from clogging and bridging within the channel.

FIELD OF THE INVENTION This invention relates generally to golf ball property measurement. Still more particularly, this invention relates to an apparatus and method for testing golf ball properties including coefficient of restitution and contact time. BACKGROUND OF THE INVENTION There is significant prior art for determining the hardness of a golf ball, including Atti compression, Reihle compression, the compression based on deformation of a ball under a 100 kg load and the compression of a ball under a 30 kg load. However, the prior art for identifying the stiffness of golf balls normally does not take into account the influence of deformation rate on “stiffness.” That is, golf ball, or core, stiffness is typically measured by means of a low rate compression test. These tests are performed by applying a fixed load or a fixed deflection to the ball or core and by measuring displacement or load, respectively. The rate of load application in these tests range from 0.1 to 60 seconds, for the various industry standard tests (e.g., Atti, Reihle). The time for deformation of a golf ball on a typical driver during an ordinary impact is on the order of 0.0005 seconds, or, on the order of 2000 times faster than industry standard compression tests. It is well known that the polymeric materials used in golf balls have rate dependent stiffness. At high rates the stiffness may be as much as 10 times greater than stiffness measured at low rate. Therefore, prior art compression or stiffness measures usually do not reflect the stiffness of a ball in actual use conditions. U.S. Pat. No. 3,509,736 to Saari discloses an apparatus for measuring the coefficient of restitution of spherical bodies. The apparatus applies a fixed velocity to the spherical body and computes the coefficient of restitution. The ball is held on a tee in an unrestrained manner. The ball is struck by a device causing the ball to move horizontally intercepting a beam from a photocell and continuing through a flight tube until it passes a light screen and a deflecting surface (such as a curtain). The device then uses the measurements to calculate the coefficient of restitution. U.S. Pat. No. 5,245,862 to Zeiss discloses a portable testing device and method for determining the coefficient of restitution of a rebounding object. The method compares the bounce periods of successive bounces of the object. A ball is dropped on a reaction plate, the ball bounces at least three times on the reaction plate. Each impact is detected and the time of the bounce interval between successive bounces is measured. The coefficient of restitution is then calculated by comparing the bounce intervals as a ratio of the time between impacts of the second bounce interval to the first bounce interval. The device includes a reaction plate with a large mass in comparison with the ball, a transducer for registering the impact of the ball. A display is also included having a timer and a clock for measuring the bounce intervals and calculating the coefficient of restitution. U.S. Pat. No. 5,672,809 to Brandt discloses a system for determining the coefficient of restitution between first and second pieces of sporting equipment. The system mounts a first piece of sporting equipment such as a bat, golf club or tennis racket. The first piece is held at a certain position and impacted by a second piece of sporting equipment, such as a baseball, golf ball or tennis ball. The device measures the velocity of the second piece of sporting equipment and the rebound velocity of the first piece of sporting equipment after impact. The coefficient of restitution is then determined using the measured information. Nevertheless, it is desirable to have an apparatus to quantify the dynamic stiffness by means of contact duration while simultaneously acquiring coefficient of restitution. SUMMARY OF THE INVENTION The present invention is directed to an apparatus for measuring the physical properties of an object, the apparatus including: a propelling device that fires the object; a striking surface facing the propelling device; a sensing unit located between the striking surface and the propelling device, wherein the sensing unit has a measuring field covering a space between the propelling device and the striking surface, and wherein the sensing unit is capable of measuring the time it takes for the object to travel a distance in the measuring field of the sensing unit; and a computing unit that calculates the impact duration between the object and the striking surface and the Coefficient of Restitution of the object, wherein the computing unit is in communication with the sensing unit. In one embodiment, the propelling device is an air cannon. In another embodiment, the mass of the striking surface is at least about 50 times greater than the mass of the object. The object preferably includes a golf ball component. In one embodiment, the sensing unit further includes a first sensing device at a first position and a second sensing device at a second position, the second sensing device being spaced apart from the first sensing device. Preferably, one of the sensing devices is a light gate. In one embodiment, the light gate is a solid state ballistics screen. In another embodiment, one of the sensing devices includes a plurality of sensors. In one embodiment, the first sensing device has a sensing field covering a first predetermined plane and the second sensing device has a sensing field covering a second predetermined plane, the second predetermined plane being parallel and at a predetermined distance Y from the first predetermined plane. In one embodiment, the predetermined distance Y is about 12 inches or greater, and in another, the predetermined distance Y is about 4 feet or greater. The apparatus can further include a third sensing device located near the striking surface for measuring the time in which the object is in contact with the striking surface. In one embodiment, the third sensing device includes a plurality of sensors. In another embodiment, the third sensing device has a sensing field covering a predetermined plane, wherein the the predetermined plane is preferably parallel and at a predetermined distance A from the striking surface. In a preferred embodiment, the predetermined distance A is about 1 inch or less, and more preferably about 0.25 inches or less. In one embodiment, at least one of the sensors is a fiber optic sensor. Preferably, the fiber optic sensor includes a computer interface card and a fiber optic receiver electrically connected to the input of the computer interface card for counting the time in which the object is in contact with the striking surface. The propelling device can fire the object in a horizontal or vertical direction. The present invention is also directed to an apparatus for the simultaneous measurement of contact time and Coefficient of Restitution of an object, the apparatus including: a propelling device that fires the object; a striking surface facing the propelling device; at least one sensing device at a first position having a first sensing plane; a timing device triggered by the at least one sensing device; at least one camera triggered by the at least one sensing device to acquire at least a first and second pair of images before and after the object contacts the striking surface, respectively; and a computing unit that calculates the Coefficient of Restitution of the object and the contact time between the object and the striking surface. Each pair of images preferably includes a first and second image taken at two discrete time intervals. In one embodiment, the apparatus further includes a second sensing device at a second position having a second sensing plane, wherein the second sensing device is parallel and at a predetermined distance A from the striking surface. The second sensing device preferably includes at least one fiber optic sensor. In one embodiment, the at least one fiber optic sensor includes a computer interface card and a fiber optic receiver electrically connected to the input of the computer interface card for counting the time in which the object stays past the second sensing device. In another embodiment, the apparatus further includes a second camera to acquire at least a third and fourth pair of images before and after the object contacts the striking surface, respectively. The present invention is also directed to a method of measuring Coefficient of Restitution and contact time of an object including the steps of: directing an object towards a striking surface; measuring a first velocity of the object before it contacts the striking surface; measuring impact duration of the object with the striking surface; measuring a second velocity of the object after it rebounds from the striking surface; and calculating the Coefficient of Restitution. In one embodiment, the method further includes the step of providing at least one sensing unit having a measuring field covering at least a portion of space between an initial position of the object and the striking surface, wherein the at least one sensing unit measures the time required for the object to travel a distance in the measuring field of the sensing unit. In another embodiment, the method further includes the step of providing a computing unit in communication with the at least one sensing unit that calculates the Coefficient of Restitution of the object and impact duration between the object and the striking surface. The mass of the striking surface is preferably at least about 50 times greater than the mass of the object. In one embodiment, the step of releasing the object is done horizontally, and in another embodiment, the step of releasing the object is done vertically. In one embodiment, the method further includes the step of providing at least one camera to acquire at least a first and second pair of images before and after the object contacts the striking surface, respectively. In another embodiment, the method further includes the step of providing a second sensing unit having a second measuring field covering a space between the at least one sensing unit and the striking surface, wherein the second sensing unit is parallel and at a predetermined distance from the striking surface. In yet another embodiment, the method further includes the step of providing a second camera to acquire at least a third and fourth pair of images before and after the object contacts the striking surface, respectively. BRIEF DESCRIPTION OF THE DRAWINGS The objects and advantages of the present invention will be better understood and more readily apparent when considered in conjunction with the following detailed description and accompanying drawings which illustrate, by way of example, preferred embodiments of the invention and in which: FIG. 1 is an arrangement of the apparatus of the present invention. FIG. 2 illustrates one embodiment of the arrangement of the apparatus of FIG. 1 according to the present invention. FIG. 3 illustrates an object in motion using the arrangement of the apparatus shown in FIG. 2 according to the present invention. FIG. 4 illustrates one embodiment of the arrangement of the apparatus shown in FIG. 1 . using two sensing devices according to the present invention. FIG. 5 illustrates another embodiment of the arrangement of the apparatus shown in FIG. 1 using two sensing devices according to the present invention. FIG. 6 illustrates another embodiment of the arrangement of the apparatus shown in FIG. 1 . using three sensing devices according to the present invention. FIG. 7 is a schematic of the third optical sensor in accordance with a preferred embodiment of FIG. 6 according to the present invention. FIG. 8 illustrates another embodiment of the arrangement of the apparatus shown in FIG. 1, using optical cameras according to the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to an apparatus for the simultaneous measurement of contact time and COR of a golf ball or golf ball core during normal use. One embodiment of the invention, shown in FIG. 1, includes an apparatus 20 having an object 36 , a propelling device 34 , a striking surface 22 , at least one sensing unit 200 , and a computing unit 500 in communication with the sensing unit. The object 36 can be any item that is able to be fired from the propelling device 34 , for example, such as a golf ball or a golf ball core. The propelling device 34 can be any device that can propel the object toward the striking surface 22 , for example, such as an air cannon, a linear motor, a translating belt, or the like. The propelling device 34 is preferably capable of propelling the object 36 at speeds from about 80 to about 180 feet/second (ft/s). In one embodiment, the propelling device 34 is an air cannon that propels the object 36 initially horizontally in the air toward the striking surface 22 . The line pressure (about 80 psi to about 90 psi) may enter a regulator in order to reduce the pressure in the air cannon to between about 40 psi to about 50 psi. In one embodiment, the air is stored in a tank (not shown). The tank can hold a volume of air, for example, about 80 cubic inches to about 90 cubic inches. A solenoid, e.g., such as a Mac Solenoid valve Model #56C-13-611JM, may be used to trigger a valve in order to release the stored pressurized air. An industrial valve, e.g., such as a Dubbin Industrial Valve C244 5001, may be used to release air into the main firing chamber to propel the object. The firing pressure is controlled by a regulator, e.g., such as a Fairchild Regulator Model #10. The object velocity can be varied by varying the pressure with the regulator. As the object 36 is released from propelling device 34 , it passes through at least one sensing device 30 . The sensing unit(s) 200 includes sensing devices which, in turn, include sensors capable of detecting passing objects. Suitable sensing devices may be obtained from Ordnance Industries, Model #6100 Solid State Ballistics Screens. The computing unit 500 includes timers and a central processing unit (CPU), and is in communication with the sensing unit 200 . The computing unit 500 can register the detection made by the sensing unit(s) 200 and can then calculate the physical response of the object 36 based on those detection measurements and other necessary information. Extra features, such as safety mechanisms and release plates, are preferably added to make the device easier and safer to use. A programmable logic controller (PLC), e.g., a Direct Logic 305 unit, may be used to automate operation. In one embodiment, the striking surface 22 is a rigid planar surface. In another embodiment, the striking surface 22 is a block, e.g., a steel block, although a metal plate or a golf club head may be equally suitable. In one embodiment, the mass of the block is preferably at least about 50 times greater than the mass of the object 36 . In another embodiment, the mass of the block is preferably at least about 100 times greater than the mass of the object 36 . As shown in FIG. 1, the propelling device 34 fires an object 36 at the striking surface 22 such that it passes through the sensing unit 200 . Preferably, the object 36 strikes the striking surface 22 (e.g., in a direction relatively normal to the striking surface 22 ) and then bounces back (e.g., also in a direction relatively normal to the striking surface 22 ). The sensing unit(s) 200 detects the presence of the object 36 , and in cooperation with timers, makes it possible to measure the time required for the object to travel between discrete distances within the space between the propelling device 34 and the striking surface 22 . The computing unit 500 computes the COR and contact time of the object 36 using the measurements of time between activation of the sensing unit(s) 200 and discrete distances between sensing unit(s) 200 . The propelling device 34 can be situated in such a way that it fires the object in any direction. Preferably, the striking surface 22 is situated such that the striking surface 22 is perpendicular to the direction in which the propelling device 34 fires the object 36 . In a preferred embodiment of the present invention, shown in FIG. 1, the propelling device 34 is situated in such a way that it fires the object 36 in a horizontal direction, i.e., perpendicular to the direction of gravity, denoted as g in FIG. 1, and the striking surface 22 is situated vertically, i.e., perpendicular to the direction in which the propelling device 34 fires the object 36 . In another embodiment of the present invention, the propelling device 34 is situated in such a way that it fires the object 36 vertically in the upward direction and the striking surface 22 is situated horizontally, i.e., perpendicular to the direction in which the propelling device 34 fires the object 36 . FIG. 2 shows another arrangement of the sensing unit 200 within the apparatus 20 shown in FIG. 1 . The sensing unit 200 enables a time measurement for an object to travel between discrete points within the space between the propelling device 34 Ha and the striking surface 22 . This measurement enables the calculation of the contact time between the object 36 and the striking surface 22 . The sensing unit 200 also enables the calculation of the velocity of the object 36 before and after the object 36 contacts the striking surface 22 . The calculation of the velocity, in turn, will enable the calculation of the COR of the object, because the COR of the object is the ratio of the outbound or rebound velocity to the inbound or impact velocity as the object strikes the striking surface in the normal direction. In FIG. 2, the sensing unit 200 includes a sensing device 30 , located in the space between the propelling device 34 and the striking surface 22 . The sensing device 30 has a sensing field covering a sensing plane 300 . The sensing device 30 preferably has an on/off switch such that, when any portion of the object 36 is in the sensing plane 300 , the on/off status changes. The timer included in the computing unit 500 , in communication with the sensing device 30 , starts and stops in accordance with the changes in the on/off status of the sensing device 30 . The time duration between the starts and stops is recorded by the central processing unit. The sensing device 30 may be a sensor with an on/off status that can signal a timer when any portion of an object 36 is in the sensing plane 300 , such as a light gate, a ballistics screen, an optical sensor, or the like. In one embodiment, the sensing device 30 is a light gate. In another embodiment, the sensing device 30 is a ballistics screen. In yet another embodiment, the sensing device 30 includes a coherent light source, such as a laser. The laser preferably has a wavelength from about 400 nanometers (nm) and about 800 nm. The laser beam is preferably split into multiple beams to form the sensing plane 300 . In one embodiment, the sensing device 30 includes a plurality of discrete sensors to provide for a widened sensing plane. The plurality of sensors may be arranged in any manner to allow sensing of an object passing through the predetermined plane. In one embodiment, a linear array of individual emitters may be arranged opposite a linear array of individual receivers. In another embodiment, a laser and beam splitter is used to emit light opposite a linear array of individual receivers. The emitters may be arranged across one edge of the predetermined plane of the sensing device and the receivers may be arranged across a directly opposing edge, although the arrangement of the plurality of sensors is not limited merely to these type of conformations. For example, an alternating linear array of individual emitters and receivers can be arranged opposite a similar alternating linear array of individual receivers and emitters. Alternately, either array may include staggering the emitters or receivers or both and/or arranging the emitters or receivers or both in blocks that may alternate, instead of alternating individual emitters and receivers. Further, according to the invention, the plurality of sensors, or the planar emitters and receivers, may be arranged so that there are an even number of edges from which signals are being emitted and by which signals are being received. In the simplest case, with a planar emitter or a linear array of individual emitters on one edge and a planar receiver or a linear array of individual receivers on a directly opposing edge, the number would be two. In another embodiment, signals can be emitted and received as above, with other signals being emitted and received in the same manner, but oriented orthogonally in the plane to the previous signals. In this embodiment, the signals would criss-cross and the number would be four (i.e., a square or rectangle where each side is capable of emitting or receiving a signal). In another embodiment, three such sets of signals can be emitted and received in the same manner as above, with each signal emitted or received being oriented at 60° to any other emitted or received signal; the number in this case would be six (i.e., a hexagon where each side is capable of emitting or receiving a signal). In yet another embodiment, four sets of signals can be emitted and received in the same manner as above, with each signal emitted or received being oriented at 45° to any other emitted or received signal; the number in this case would be eight (i.e., an octagon where each side is capable of emitting or receiving a signal). Alternately, the plurality of sensors may be arranged so that the individual emitters and receivers are situated opposite each other in any arrangement, so that the shape defined by those emitters and receivers is circular within the predetermined plane of the sensing device. In FIG. 2, the sensing device 30 is arranged in such a way that the sensing plane 300 is parallel to the striking surface 22 . The distance between the sensing plane 300 and the striking surface 22 , D, is greater than the dimension of the object 36 (e.g., the diameter of the golf ball), d. After the object 36 is fired from the propelling device 34 , it passes through the sensing plane 300 . The sensing device 30 transmits a signal to the computing unit 500 , causing the timer to start and the central processing unit to record the start time t 1 , when the foremost point of the object 36 enters the sensing plane 300 . The sensing device 30 then sends another signal to the computing unit 500 to register the time t 2 , when the rearmost point of the object 36 leaves the sensing plane 300 . When the object 36 rebounds back from the striking surface 22 and passes through the sensing plane 300 , the sensing device 30 transmits another signal to the computing unit 500 to register the time t 3 , when the foremost point of the object enters the sensing plane 300 . The sensing device 30 sends yet another signal to the computing unit 500 , registering time t 4 , when the rearmost point of the object leaves the sensing plane 300 . Based on the assumption that the object 36 travels at a constant speed v 1 , in a direction normal to the striking surface 22 before striking, and that the sensing plane 300 is parallel to the direction of gravity, the speed v 1 can be calculated as the ratio of the dimension of the object 36 to the time duration for the object 36 to go through the sensing plane 300 the first time: v 1 =d/(t 2 −t 1 ). Similarly, based on the assumption that the object 36 travels at another constant speed v 2 , in a direction normal to the striking surface 22 after striking it, and that the sensing plane 300 is parallel to the direction of gravity, the speed v 2 can be calculated as the ratio of the dimension of the object 36 to the time duration for the object 36 to go through the sensing plane 300 the second time: v 2 =d/(t 4 −t 3 ). The Coefficient of the Restitution (COR) can therefore be calculated as v 2 /v 1 , or (t 2 −t 1 )/(t 4 −t 3 ). FIG. 3 illustrates that upon initially leaving the sensing plane 300 , the object 36 travels a distance of (D−d) at the speed v 1 normal to the striking surface 22 before contact. This takes a time period of P 1 =(D−d)/v 1 . Likewise, after leaving the striking surface 22 , the object 36 travels a distance of (D−d) at the speed v 2 normal to the sensing plane 300 before entering the second time. This takes a time period of P 2 =(D−d)/v 2 . Because the object 36 stays past the sensing plane 300 (moving toward the striking surface 22 ) for a total time of t 3 −t 2 , i.e., after leaving the sensing plane 300 initially and before reentering the sensing plane 300 the second time, the contact time between the object 36 and the striking surface 22 , t bc , is: t bc = ( t 3 - t 2 ) - P 1 - P 2 = ( t 3 - t 2 ) - ( D - d ) / v 2 - ( D - d ) / v 2 = ( t 3 - t 2 ) - ( D - d )  ( t 4 - t 3 ) / d - ( D - d )  ( t 2 - t 1 ) / d . FIG. 4 shows another arrangement of the apparatus 20 shown in FIG. 1 . In comparison to the embodiment shown in FIGS. 2 and 3, in this embodiment, the sensing unit 200 includes a first sensing device 30 and a second sensing device 32 , each having a sensing field covering a first sensing plane 300 and a second sensing plane 310 , respectively. The second sensing device 32 , located in the space between the first sensing device 300 and the striking surface 22 preferably has an on/off switch such that, when any portion of the object is in the second predetermined plane, the on/off status changes, as discussed with respect to the on/off switch of the sensing device 30 in FIGS. 2 and 3. The second sensing device 32 may also be a sensor with an on/off status to signal a timer when any portion of an object 36 is in the second sensing plane 310 , such as a light gate, a solid ballistics screen, or a fiber optic sensor. In a preferred embodiment, the second sensing device 32 is a light gate. In another preferred embodiment, the second sensing device 32 is a ballistics screen. In yet another preferred embodiment of the present invention, the second sensing device 32 includes a plurality of sensors to provide for a widened second sensing plane 310 . In yet another embodiment, the second sensing device 310 includes a coherent light source, such as a laser. The laser preferably has a wavelength from about 400 nanometers (nm) and about 800 nm. The laser beam is preferably split into multiple beams to form the second sensing plane 310 . In FIG. 4, the second sensing device 32 is arranged in such a way that the second sensing plane 310 , like the first sensing plane 300 , is also parallel to the surface of the striking surface 22 . The distance between the second sensing plane 310 and the first sensing plane 300 is Y and the distance between the second sensing plane 310 and the striking surface 22 is Z. Similar to FIGS. 2 and 3, Z is greater than d, the dimension of the object. After the object 36 is fired from the propelling device 34 , it passes through the first sensing plane 300 and then the second sensing plane 310 . The first sensing device sends a signal to the computing unit 500 , causing the timer in the computing unit to start and the central processing unit to record the time t 1 , when the foremost point of the object 36 enters the first sensing plane 300 . The second sensing device 32 also sends a signal to the computing unit 500 , causing the timer in the computing unit to start at time t 2 and the central processing unit to record the time t 2 , when the foremost point of the object 36 enters the second sensing plane 310 . When the object 36 rebounds back from the striking surface 22 and passes through the second sensing plane 310 and then the first sensing plane 300 , the second sensing device sends another signal to the computing unit 500 to register the time t 3 , when the foremost point of the object 36 enters the second sensing plane 310 the second time. The first sensing device 30 also sends a signal to the computing unit 500 to register the time t 4 , when the foremost point of the object 36 enters the first sensing plane 300 the second time. Based on the assumption that the object 36 travels at a constant speed v 1 , in a direction normal to the striking surface 22 before contact, and that the sensing planes 300 , 310 are parallel to the direction of gravity, the speed v 1 can be calculated as the ratio of the predetermnined distance Y between the first sensing plane 300 and the second sensing plane 310 to the time duration for the object 36 to travel between the sensing planes: v 1 =Y /( t 2 −t 1 ). Similarly, based on the assumption that the object 36 travels at another Iconstant speed v 2 , in a direction normal to the striking surface after contact, and that the sensing planes 300 , 310 are parallel to the direction of gravity, the speed v 2 can be calculated as the ratio of the predetermined distance Y between the first and the second sensing planes 310 to the time duration for the object 36 to travel between the sensing planes: v 2 =Y /( t 4 −t 3 ). The Coefficient of the Restitution (COR) can therefore be calculated as v 2 /v 1 , or (t 2 −t 1 )/(t 4 −t 3 ). Similar to the situation shown in FIG. 3, after entering the second sensing plane 310 the first time, the object 36 travels a distance of Z at the speed v 1 , in a direction normal to the striking surface 22 before contact. This time period is P 1 =Z/v 1 . Likewise, after leaving the striking surface 22 , the object 36 travels a distance of (Z−d) at the speed v 2 , normal to the second sensing plane 310 , before entering it the second time. This time period is P 2 =(Z−d)/v 2 . Because the object 36 stays past (toward the striking surface with respect to) the second sensing plane 310 for a total time of t 3 −t 2 , i.e., after leaving the second sensing plane 310 the first time and before entering the second sensing plane 310 the second time, the contact time between the object 36 and the striking surface 22 , t bc , is: t bc = ( t 3 - t 2 ) - P 1 - P 2 = ( t 3 - t 2 ) - ( Z - d ) / v 2 - ( Z - d ) / v 1 = ( t 3 - t 2 ) - ( Z - d )  ( t 4 - t 3 ) / Y - Z  ( t 2 - t 1 ) / Y . Although FIG. 4 is a more complex arrangement and requires two sensing devices, instead of only one sensing device as shown in FIGS. 2 and 3, this arrangement has a distance Y between the two sensing planes, which is significantly larger than that dimension d of the object 36 . This difference in dimensions provides enhanced accuracy for the velocity measurement of the object 36 . In one embodiment, the distance Y is about 12 inches or greater. In another embodiment, the predetermined distance Y is about 4 feet or greater. FIG. 5 shows another arrangement of the apparatus 20 using two sensing devices. In this arrangement, the second sensing device 32 is located much closer to the striking surface 22 than as illustrated in FIG. 4 . Consequently, the distance between the second sensing plane 310 and the striking surface, Z, is less than the dimension, d, of the object 36 . In this embodiment, the first and second sensing devices 30 , 32 send signals to the computing unit 500 in the same way prior to the object contacting the striking surface 22 , i.e., after the object 36 is fired from the propelling device 34 , it passes through the first sensing plane 300 and then the second sensing plane 310 . The first sensing device 30 sends a signal to the computing unit 500 to register the time t 1 , when the foremost point of the object enters the first sensing plane 300 . The second sensing device 32 also sends a signal to the computing unit 500 to register the time t 2 , when the foremost point of the object 36 enters the second sensing plane 310 . However, the first and second sensing devices 30 , 32 send signals to the computing unit 500 in a different way after the object contacts the striking surface 22 . Because the distance between the second sensing plane 310 and the striking surface 22 , Z, is less than d, the dimension of the object, the object can not leave the second sensing plane 310 before contacting the striking surface 22 . The object is also not able to enter the second sensing plane 310 a second time after contacting the striking surface 22 . Instead, the object remains in the second sensing plane 310 when in contact with the striking surface 22 . Thus, when the object 36 rebounds back from the striking surface 22 , the second sensing device 32 sends a signal to the computing unit 500 to register the time t 3 , when the rearmost point of the object 36 leaves the second sensing plane 310 , instead of when the foremost point of the object enters the second sensing plane 310 the second time. The first sensing device 30 , like before, sends a signal to the computing unit 500 to register the time t 4 , when the foremost point of the object enters the first sensing plane 300 the second time. Based on the assumption that the object travels at a constant speed v 1 , in a direction normal to the striking surface before contact, and that the sensing planes 300 , 310 are parallel to the direction of gravity, the speed v 1 can be calculated as the ratio of the distance Y between the sensing planes 300 , 310 to the time duration for the object to travel between the first and second sensing planes 300 , 310 the first time: v 1 =Y /( t 2 −t 1 ). Similarly, based on the assumption that the object travels at another constant speed v 2 , in a direction normal to the striking surface after contact, and that the sensing planes 300 , 310 are parallel to the direction of gravity, the speed v 2 can be calculated as the ratio of the distance Y between the first and the second predetermined planes minus the object diameter d to the time duration for the object to travel between the sensing planes 300 , 310 the second time: v 2 =( Y−d )/( t 4 −t 3 ). The Coefficient of the Restitution (COR) can therefore be calculated as v 2 /v 1 , or (Y−d)(t 2 −t 1 )/[Y(t 4 −t 3 )]. After entering the second sensing plane 310 , the object 36 travels a distance of D at the speed v 1 normal to the striking surface 22 before contact. This requires a time period of P 1 =D/v 1 . Likewise, after leaving the striking surface, the object travels a distance of D at the speed v 2 normal to the second sensing plane 310 before leaving the second sensing plane 310 . This requires a time period of P 2 =D/v 2 . Because the object 36 stays within the second sensing plane 310 for a total time of t 3 −t 2 after entering and before leaving the second sensing plane 310 , the contact time the object 36 makes with the striking surface 22 , t bc , is: t bc = ( t 3 - t 2 ) - P 1 - P 2 = ( t 3 - t 2 ) - Z / v 2 - Z / v 1 = ( t 3 - t 2 ) - Z  ( t 4 - t 3 ) / ( Y - d ) - Z  ( t 2 - t 1 ) / Y . As discussed with respect to the embodiment shown in FIG. 4, although FIG. 5 shows a more complex dual sensing device arrangement, the distance Y between the two sensing planes 300 , 310 , which is significantly larger than the dimension of the object d, provides a more accurate measurement of the velocity of the object 36 and contact time with the striking surface 22 . In order for this embodiment to provide accurate measurements, the distance Z between the second sensing plane 310 and the striking surface 22 must be small. In a preferred embodiment of the present invention, the distance Z is about 1 inch or less. In another preferred embodiment of the present invention, the distance Z is about 0.25 inches or less. In yet another preferred embodiment of the present invention, the distance Z is about 0.13 inches or less. FIG. 6 shows another arrangement of apparatus 20 of the present invention. In this embodiment, the sensing unit further includes a third sensing device 38 , in addition to the first sensing device 30 and second sensing device 32 of FIGS. 4 and 5. The third sensing device 38 is located near the striking surface 22 . It has a sensing area covering an third sensing plane 320 that is parallel to the striking surface 22 . The third sensing device 38 is designed specifically for the purpose of enabling the registration of the time duration during which any part of the object 36 is in the third sensing plane 320 . According to this embodiment, after the object 36 is fired from the propelling device 34 , the first and second sensing devices 30 , 32 signal the computing unit 500 to register the time duration t 1 between the time when the foremost point of the object 36 enters the first sensing plane 300 and the time when the foremost point of the object 36 enters the second sensing plane 310 . The computing unit 500 also registers the time duration T b during which the object 36 stays in the third sensing plane 320 . When the object 36 rebounds back from the striking surface 22 , the sensing devices signal the computing unit 500 to register the time duration t 2 between the time when the foremost point of the object 36 enters the second sensing plane 310 the second time and the time when the foremost point of the object enters the first sensing plane 300 the second time. Based on the assumption that the object 36 travels at a constant speed v 1 , in a direction normal to the striking surface 22 before contact, and that the sensing planes are parallel to the direction of gravity, the speed v 1 can be calculated as the ratio of the predetermined distance Y between the first and the second sensing planes 300 , 310 to the time duration for the object to travel between the two sensing planes the first time: v 1 =Y/t 1 . Similarly, based on the assumption that the object travels at another constant speed v 2 , in a direction normal to the striking surface 22 after contact, the speed v 2 can be calculated as the ratio of the predetermined distance Y between the first and the second sensing planes 300 , 310 to the time duration for the object to travel between the two sensing planes the second time: v 2 =Y/t 2 . The Coefficient of the Restitution (COR) can therefore be calculated as v 2 /v 1 , or t 1 /t 2 , and the contact time between the object 36 and the striking surface 22 , t bc , can be considered equivalent to the time duration T b during which the object 36 stays in the second sensing plane 310 minus the inbound and outbound flight time to transit the distance Y2. Thus, t bc =T b −Y 2 /v 1 −Y 2 /v 2 . In order for this embodiment to provide accurate measurements, the distance Y 2 between the third sensing plane 320 and the striking surface 22 must be small. In a preferred embodiment of the present invention, the distance Y 2 is about 1 inch or less. In another preferred embodiment of the present invention, the distance Y 2 is about 0.25 inches or less. In yet another preferred embodiment of the present invention, the distance Y 2 is about 0.13 inches or less. The striking surface 22 in this embodiment is preferably a rigid block or metal plate. The apparatus 20 is preferably set up to operate in a horizontal position with the sensing planes 300 , 310 , 320 parallel to the direction of gravity. In one embodiment, the third sensing device 38 is a fiber optic sensor including a planar optical emitter and a planar optical receiver adjacent to the striking surface 22 . The use of fiber optic sensors is advantageous because: (1) balls and cores are usable without modification of the apparatus; (2) fiber optic components and associated electronic signal processing hardware may be designed to operate at switching frequencies of 500 kHz which resolves contact time to an accuracy of 2 microseconds; and (3) the use of fiber optics significantly reduces problems associated with radio frequency induced electronic noise. Contact time may also be measured by placing conductive foil on the object 36 and by placing a lattice of conductors on the striking surface 22 . When the object 36 is in contact with the striking surface 22 , the resistance of the lattice can vary measurably. Contact duration is generally linked to the duration of the resistance change. This technique is effective but can have deficiencies in comparison to the optical technique. The deficiencies can include: 1) alteration of the balls or cores to have conductive surfaces; 2) the conductive lattice sustaining damage after repeated impact; and 3) the electronic circuits required to measure resistance variations are prone to radio frequency noise and do not operate at as high a frequency as the optical technique disclosed above. FIG. 7 shows a preferred third sensing device 38 in detail. The third sensing device 38 includes a light or other energy source 58 and receiver 60 . The planar emitter 24 , or other energy transmitter, preferably includes a number of components. A power supply 62 , e.g., such as a regulated 12 volt 0.5 amp DC power supply, is connected to an adjustable monolithic regulator 64 . This adjustable voltage is applied to an energy emitter 66 , such as a lamp, e.g., a #349 miniature incandescent lamp, that is preferably within an enclosed housing 68 . The housing 68 should generally accept a standard fiber optic assembly 70 , e.g., such as one that has a thin, flat dispersion at the opposed end 72 . The opposed end may be held in position, e.g., by a Ultra High Molecular Weight polyethylene panel (UHMW panel) 74 , held and constrained in position by flat ceramic magnets 76 . Typically, the panel 74 is slightly removed from the striking surface 22 by a short distance A, which is preferably about 0.25 inches or less, and is cut away to form an opening 80 in the center such that a golf ball may pass through and strike the rigid block 78 . A fiber assembly 70 is placed at this opening 80 and opposes a second fiber assembly 82 directly across the opening 80 , which forms part of the optical planar receiver 26 . At the opposite end 84 , 92 of each fiber assembly 82 , 70 is an identical fiber assembly contained within an enclosed housing 68 , 86 is an optic receiver 66 , 88 . In a preferred embodiment, each optic receiver 66 , 88 is an inverting fiber optic receiver, e.g., such as Honeywell Model HFD-3031. Each inverting fiber optic receiver is electrically connected to the input of a counter/timer computer interface card 64 , 90 . The counter/timer computer interface card 64 , 90 preferably has an operating frequency of about 500 kHz or greater, more preferably about 1 MHz or greater. The operating frequency should be advantageously selected to provide as much accuracy and resolution as possible for contact time and COR measurements. Another embodiment of the present invention is shown in FIG. 8, similar to the arrangement shown in FIG. 4 using two sensing devices in combination with one or more optical cameras. In this embodiment, the sensing unit 200 includes a first sensing device 30 and a second sensing device 32 , each having a sensing field covering a first is sensing plane 300 and a second sensing plane 310 , respectively, that are parallel to the surface of the striking surface 22 . A camera system 325 includes at least one camera and lighting unit. At least two optical cameras are preferred to triangulate the space with triggers and timers. FIG. 8 illustrates this embodiment in which the camera system 325 includes a first camera 330 and a second camera 340 , positioned in between the sensing planes 300 , 310 . The sensing devices 30 , 32 may also be sensors with an on/off status to simultaneously signal at least one timer in the computing unit 500 and the camera system 325 when any portion of an object 36 passes through the first or second sensing planes 300 , 310 . For example, the sensing devices 30 , 32 may be coherent light sources, such as lasers. The sensing devices 30 , 32 may communicate via an asynchronous protocol through the computing device 500 to the camera system 325 and timers to control activation. The camera system 325 preferably includes a lighting system, such as a dual strobe lighting unit, and a filtering system, for each camera used. The cameras 330 , 340 used in this embodiment are preferably electro-optical cameras with light-receiving apertures, shutters, and light sensitive silicon panels as discussed in U.S. Pat. No. 5,575,719, which is incorporated in its entirety by reference herein. Multishutter cameras may also be used as disclosed in co-pending application Ser. No. 09/379,592, the contents of which are incorporated in its entirety by reference herein. Suitable commercially available cameras include, but are not limited to, ELECTRIM EDC-1000U Computer Cameras (EDC Cameras) from Electrim Corporation in Princeton, N.J. Charge coupled device or CCD cameras are preferred, but TV-type video cameras are also useful. In one embodiment, the camera is a CCD camera with about 90,000 pixels or greater. In a preferred embodiment, the camera has about 300,000 pixels or greater, and, more preferably, the camera has about 1,000,000 pixels. FIG. 8 illustrates an object 36 in various positions I-IV after firing from the propelling device 34 on the outbound trip to the striking surface 22 , and on the return (inbound) flight, V-VIII, after contacting the striking surface 22 . After the object 36 is fired from the propelling device 34 , it passes through the first sensing plane 300 . When the foremost point of the object 36 enters the first sensing plane 300 (Position I), the first sensing device 30 sends a signal to the computing unit 500 to activate the camera system 325 . Once activated, the cameras 330 , 340 each acquire a first image, e.g., Position II. After a known time interval (t c ), the cameras 330 , 340 each acquire a second image, e.g., Position III. The object 36 then moves through the second sensing plane 310 (Position IV) and the computing unit 500 receives a signal from the sensing device 32 to store a time t 2 . The object 36 then continues along the flight path (FP out ), impacts the striking surface 22 , and rebounds, following the inbound flight path (FP in ). As the object 36 moves into Position V, the sensing device 32 again activates the cameras 340 , 330 and sends a signal to the computing unit to record a time t 3 . The cameras 340 , 330 each acquire a pair of images, e.g., Positions VI and VII. The first and second images acquired by each camera make it possible to triangulate the spacial coordinates of the object 36 at each image capture, which allows for the determination of the distance between the object 36 at Positions II and III, and Positions VI and VII, to be determined. In another embodiment, however, a dual camera system is used, but each camera has a single flash. In yet another embodiment, a single camera is used. Because a dual camera system is used. Based on the assumption that the object 36 travels at a constant speed v 1 , in a direction normal to the striking surface 22 before contact, and that the sensing planes 300 , 310 are parallel to the direction of gravity, the speed v 1 can be calculated as the ratio of the distance D 1 between the first and second image and the time between each image capture t c :   v 1 =D 1 /t c . Similarly, based on the assumption that the object 36 travels at another constant speed v 2 on the inbound flight path (FP in ) after contact, in a direction normal to the striking surface, and that the sensing planes 300 , 310 are perpendicular to the direction of gravity, the velocity v 2 can be calculated as the ratio of the distance D 2 between the first and second images and the time between each image capture t c : v 2 =D 2 /t c . The Coefficient of the Restitution (COR) can therefore be calculated as v 2 /v 1 , or D 2 /D 1 . Similar to the situation shown in FIG. 4, after passing through the sensing unit 32 (Position IV), wherein time t 2 is logged, the object travels a distance of C at the speed v 1 , in a direction normal to the striking surface 22 before contact. This time period is P 1 =C/v 1 . Likewise, after leaving the striking surface 22 , the object 36 travels a distance of C at the speed v 2 , in a direction normal to the second sensing plane 310 , before passing back through the sensing unit 32 at time t 3 (Position V). This time period is P 2 =C/v 2 . Because the object 36 stays past (toward the striking surface with respect to) the sensing unit 32 for a total time of t 3 −t 2 , the contact time between the object 36 and the striking surface 22 , t bc , is: t bc = ( t 3 - t 2 ) - P 1 - P 2 = ( t 3 - t 2 ) - C / v 1 - C / v 2 = ( t 3 - t 2 ) - C  ( t c ) / D 1 - C  ( t c ) / D 2 . Any number of ways can be used to calibrate the apparatus 20 . For example, when calibrating the system using sensing devices, but no optical cameras, an object 36 may be attached to a measurement device, e.g., such as a dial indicator (not shown). The object is introduced into the path 96 of the normal flight of the object 36 toward the striking surface 22 , as shown in FIG. 7 . When sufficient light is obstructed, the optic receiver will indicate a HIGH reading. The distance between the striking surface 22 and the position of the object 36 when the receiver indicates a HIGH signal is measured. In the embodiment shown in FIG. 6, this distance is Y 2 and is required in the computation of the contact time. The time it takes for the object 36 to contact the striking surface 22 and rebound through the distance Y 2 can be subtracted from the duration of time that the HIGH signal is maintained to correct the contact time measurement. EXAMPLES These and other aspects of the present invention may be more fully understood by reference to the following tests. While these tests are meant to be illustrative of the apparatus made according to the present invention, the present invention is not meant to be limited by the following tests. Testing was performed on various balls using the apparatus of the present invention. As is shown in Table 1 below, the HP Eclipse™, a double core ball, and the DT™ two-piece, a two-piece ball, have similar compressions when measured on an Atti compression machine, yet their contact times or impact stiffness measured at a velocity of about 250 ft/s are significantly different. The HP Eclipse™ has a much longer contact time or lower impact stiffness, and a softer feel. TABLE 1 Atti Ball Compression Velocity COR Contact Time DT 2-Piece ™ 92.7 254.43 0.817 422.9 HP Eclipse ™ 92.2 250.67 0.793 451.4 Thus, contact time is a better measure of ball stiffness than static compression testing. While it is apparent that the illustrative embodiments of the invention herein disclosed fulfills the objectives stated above, it will be appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. For example, another device could be used for shooting the object out toward the massive block, the device may be oriented at any angle with respect to gravity, or other calculations based on simple trigonometric functions may be employed along with the recorded measurements to account for the effect of the gravitational force on the calculation of the COR. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments which come within the spirit and scope of the present invention.

An apparatus and method for quantifying the stiffness of a golf ball or golf ball core under normal use conditions while also measuring the contact time, wherein an air cannon, or the like, is used to shoot an object horizontally against a block while the inbound and outbound velocities of the object are measured by two light gates separated by a given distance and the contact time is measured by optical sensors located at the block, and wherein the measured times and calculated velocities are then used to calculate the coefficient of restitution and contact time of the object.

This application is a continuation of application Ser. No. 288,740 filed July 31, 1981 now abandoned. BACKGROUND OF THE INVENTION The invention relates to an environmental control system and, more particularly, to an environmental control system for use in greenhouses or the like and preferably utilizing existing power transmission lines for communication among elements of the control system. Control of the temperature, humidity and the other measurements in a greenhouse or the like to permit the control of the environment therein can necessitate monitoring and controlling numerous sensing and control devices at various locations within the building being environmentally controlled. Due to the large number of measurements and functions that are needed to be performed, computer based or computer compatible systems have been used to centrally control the monitoring and operating functions of an environmental control system, such as in a large building. With the advent of complex systems of environmental control a great need has evolved for monitoring systems capable of monitoring a myriad of points with respect to conditions which must be continuously observed in order to assure proper and safe operation. Similarly, alarm conditions at the points must be immediately discovered and corrected, thus requiring systems that are capable of indicating alarm conditions as well as scanning the points. Due to the great number of remote field points that must be monitored, conventional monitoring systems utilize a control center as a receiving and sending station for monitoring the remote points which generally are scattered over great distances. Some conventional systems utilize pulse width modulation or frequency modulation to address and monitor the field points; however, these systems are extremely complex and expensive and are desirable only where extremely great distances are involved or in underdeveloped or inaccessible locations where the use of cable wires is impractical. For environmental control in a building or complex of buildings pulse width modulation and frequency modulation systems are impractical, and systems for such application are generally based on the matrix concept as can be seen from U.S. Pat. No. 3,300,759. While the use of matrices and binary coded addresses for field points does reduce the number of wires required below the nunber of wires required for each point to be individually connected to the control central, the reduction in the number of wires is not as great as is desirable, and the number of wires required is dependent upon the number of points monitored thereby decreasing sysem flexibility. These conventional systems suffer from the disadvantages of difficult installation due to the different addresses associated with each field location and difficult system modification once the system has been installed as well as high cost of wiring. That is, each field location must be designed for a specific address thereby increasing inventory and installation time; and, if at any time additional field locations are desired to expand the system beyond the original design, additional wires are required to be installed. Systems have been devised for reducing the number of dedicated communications wires resquired, such as shown in U.S. Pat. No. 3,613,092, but still suffer from the cost, time, and reliability disadvantages of requiring dedicated custom installed communications wiring. Greenhouses provide weather protection for tender plants. Cultivation of the plants requires the atmosphere within the greenhouse to be maintained at a selected temperature and humidity level. Factors affecting the greenhouse atmosphere include heat gains and heat losses. For example, during long periods of sun exposure, abnormal amounts of solar energy enter the greenhouse which tends to raise the temperature. Logical control of greenhouse environmental conditions has heretofore utilized, for example, 24 volt control systems with relays and solenoids individually wired together and strung out, or a computer based equivalent system (such as a programmable controller) with dedicated wires for communication and control strung out and wired among all control points and sensors. These systems have proved less than adequate in terms of cost, time for installation, each of maintenance, repair, and update of equipment. Additionally, communication among elements of the environmental control system has been restricted to dedicated control and communications custom wiring. Thus, expansions required a new wiring installation or modification requires a rewiring of the system. A significant disadvantage of many prior systems involved the system reliability and maintainability, in that a breakdown in one part of the system could effectively shut down other parts of the system. Thus, to increase reliability, redundant or backup equipment was often necessitated. SUMMARY OF THE INVENTION Accordingly, a general object of the invention is to provide a new and improved environmental control system which has general applicability to buildings of all kinds including but not limited to greenhouses. A further object of the present invention to provide a control system not requiring dedicated independent wires for communication among elements of the control system. Another object of the present invention is to permit expansion of an original control system without the necessity of running additional wires from a control center. Another object of the present invention is to utilize similar communications interfaces at each field point to reduce inventory. It is a further object of the present invention to provide an improved environmental control system especially suited for use in a greenhouse which provides for bidirectional communications between a central controller and peripheral elements of an environmental control system utilizing existing AC power transmission line wiring. BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages will become apparent upon reading the following detailed description while referring to the attached drawings, in which: FIG. 1 is a block diagram of a system embodying the present invention; FIG. 2 is a system block diagram of an alternate embodiment of the present invention; FIG. 3 is a front perspective view of a user interface and environmental control unit embodiment of the present invention; FIGS. 4A-4C are detailed schematic drawings of the electronic circuitry comprising the digital electronics of the environmental control unit of FIG. 3; FIG. 5 is a schematic of the keyboad of the environmental control unit of FIG. 3 illustrating the interconnect to the electronics of FIGS. 4A-4C; FIG. 6 is an electrical schematic diagram of the display of the electronic control unit of FIG. 3, illustrating the interconnect to the electronic circuitry of FIGS. 4A-4C; FIG. 7 is a block diagram of a vent control system embodiment of the present invention, illustrating a stand alone vent control system; FIG. 8 is a block diagram of an alternate embodiment of the present invention illustrating an alternate stand alone vent control system; FIG. 9 is a functional block diagram illustrating the stand alone vent control system of FIG. 8 in more detailed block diagram form; FIG. 10 is a block diagram of a centralized control vent control system embodiment of the present invention illustrated; FIG. 11 is a block diagram of a vent motor actuator system and interfaces detailing the vent motor actuator unit of FIGS. 8 and 10; FIG. 12A is a detailed block diagram detailing functional electronic blocks within the motor actuator unit of FIG. 11; FIG. 12B is a detailed schematic of an embodiment of the vent motor actuator unit of FIGS. 11-12; FIGS. 13A-13C are detailed electrical schematic diagrams of a modular communications interface control processor hardware system, such as that of FIGS. 1 and 2, additionally illustrating the electronics for the outdoor and indoor aspirators; FIG. 14 is a partial schematic partial block diagram illustrating a single speed exhaust fan control system embodiment of the present invention; FIG. 15 is a partial schematic partial block diagram of a two speed exhaust fan embodiment of the present invention; FIG. 16 is a detailed electrical block diagram of the single speed exhaust fan controller and modular communications interface of FIG. 14; FIG. 17 is a detailed electrical block diagram of a dual function low voltage controller embodiment of the present invention; FIG. 18 is a block diagram of a modular communications interface and steam heater controller embodiment of the present invention; FIG. 19 is a block diagram of a modular communications interface and FACT Impeller system embodiment of the present invention; FIG. 20A is a detailed electrical schematic of a first embodiment of the modular communications interface means; and FIG. 20B is a detailed electrical schematic of a second embodiment of the modular communication interface means. BRIEF DESCRIPTION OF THE SOFTWARE LISTINGS A software listing of the program for the Modular Communication Interface Control Processor is located at pgs. 61-82; and A software listing of the program for the Central Control Processor illustrating the vent control embodiment is located at pgs. 83-178. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and particularly to FIG. 1, a system embodiment of the present invention is shown. A plurality of modular communications interface (MCI) means 100 are coupled preferably to an AC power transmission line, and are additionally coupled individually to an environmental control unit 110 and to respective peripheral control means, elements 120, 130, 140, 150, 160, 170, 180 and 190. The modular communications interface means 100 provides for bidirectional data communications among the environmental control unit 110 and peripheral control means preferably over existing power transmission lines. Thus, address, command, and data signals can be intercoupled between elements of the system utilizing existing power wiring without necessitating special dedicated communications wiring. The peripheral control elements can be of many types. For example in an environmental control system, the peripheral control elements may be sensors, such as wind sensor 120, rain sensor 130, photocell sensor 150, temperature aspirator (sensor) 170, temperature sensor 180, and humidistat 190. Each of these peripheral control element sensors is individually addressable, and is responsive to a predefined address as received via the respective associated modular communications interface means. When a proper address signal is received and decoded by the peripheral control element, and a proper command is received, the respective sensor provides a sensor output signal in accordance with its functionality. These sensors can detect not only absolutes (e.g. presence or absence), but can also detect relative values (e.g. values above a predefined threshold) in accordance with the system definition and configuration. Other types of peripheral control elements include vent motor control means 140 which provides control of speed and direction of vent movement, single speed fan controllers, dual speed fan controllers, single and dual function low voltage control systems, boiler control means, heat and humidity controllers, etc., as shown by functional block 160 of FIG. 1. For controlling environments in structures other than greenhouses, the peripheral control elements may vary in terminology and in function from that described herein and still fall within the purview of this invention. Likewise, it is possible to use radio frequency communication or dedicated lines rather than the power transmission lines and still use many of the claimed features of the present invention as will become apparent hereinafter from reading the description of the invention and a reading of the appended claims. Referring to FIG. 2, an alternate embodiment of the invention illustrating a programmable environmental control system is shown. An environmental control unit or central control processor 110 is coupled to an associated modular communications interface means 100 which provides for bidirectional communication between he processor 110 and selected peripheral control elements 101, 102, and 103, over existing power transmission lines via respective other modular communications interface means 100. Thus, the central control processor 110 can communicate with peripheral control elements 101, 102, and 103, via the modular control interface means 100 associated (independently) with each of the peripheral control elements and with the central control processor, over existing AC power transmission lines. Additionally, some peripheral control elements may perform functions offline, and thus do not require communications with the central control processor 110. These peripheral control elements thus do not require a modular communications interface 100 to be associated with them. Programmable control elements 104 and 105 illustrate off network peripheral control elements. In this illustrated embodiment, the environmental control unit 110 performs a number of functions. First, it provides a central control processor (CCP) comprising a central processing unit, and memory, coupled to input means such as a keyboard and/or switches, and coupled to a display means, such as a cathode-ray tube video display or a printer. Additionally, nonvolatile magnetic storage can be provided such as by disc tape, bubble memory, etc. The central control processor of the environmental control unit 110 in accordance with stored program instructions, user input data, command sequences, set points, and threshold values, performs the functions of system configuration control, task sequencing for control of the PCES, communications linkage and protocol, system diagnostics, user interface, and storage and archiving. In another implementation vent controller unit may be utilized as the environmental control unit in conjunction with a vent motor actuator means emboding a PCE to provide for a stand alone vent, control system, as discussed with reference to FIGS. 7-9, hereinafter. A software listing of one embodiment of a vent control unit is included after the detailed description as pages 84-180. The modular communications interface means 100 may be comprised of a stand alone system, packaged on a single printed circuit card, or may be combined with sensing and control functions in a single system. Referring to FIG. 3, an illustrative embodiment of the housing and front panel of an environmental control unit 110, as discussed with reference to FIGS. 1 and 2, is shown. The front panel is comprised of a keyboard 210, which contains keys which allow user input of numerics (0-9), and function specification (e.g. temperature, time, set, displacement, AM, PM, and auto or manual). The user enters appropriate data via the keyboad 210 for utilization by the central control processor of the environmental control unit 110. A master on/off switch 240 is provided to allow user control of system status. Display is provided on the front panel by means of alphanumeric display means 220, such as 7, 9, 11, or 13 segment LED, LCD, electrochrometic, vacuum fluorescent, etc. display means. Additionally, individual point light displays, such as light emitting diodes, can be used to indicate AM, 230, PM, 231, manual operational mode 233, and standby power, 232. Alternatively, other combinations of number and type digit displays, individual point displays, and number and function keys within the keyboard 210 can be provided according to the system requirements and user needs. Alternatively, other input means may be provided, such as a typewriter style keyboard, or a plurality of switches, or other appropriate means. Referring to FIGS. 4a-c, an electrical schematic diagram is provided illustrating the electronics contained within the embodiment of FIG. 3. A central processing unit 250 performs keyboard, switch, and display interface functions in accordance with stored program instructions as output from memory 255 (nonvolatile ROM in the illustrated embodiment) and in accordance with stored data signals from read write memories 260 and 265. In the illustrated embodiment, an Intel 8035 microprocessor is utilized. This processor has a multiplexed address and data busses, and therefore requires the utilization of a latch 252 to prolong address signed outputs after multiplexing occurs to place the data signals on the multiplexed bus. Alternatively, the processor 250 and latch 252 may be replaced by other types of central processing units, either with or without external memory so as to obviate the need for the latch 252, EPROM 255, and RAMS 260 and 265. Alternatively, other types of discrete logic or microprocessor based systems may be used requiring different combinations of read-write memory and read only memory. Logic circuit 254, a 74LSOO quad NAND gate in the illustrated embodiment, provides device select functions for differentiating between addressing of the read-write memories 260 and 265, the read only memory 255, and a Universal-Synchronous-Asynchronous-Receiver-Transmitter (USART) 270. In the illustrated embodiment, the USART 270 is an Intel 8251A integrated circuit. Alternatively, other types of receiver-transmitter systems can be utilized, such as a UART (Universal-Asynchronous-Receiver-Transmitter) or this function may be included as a programmed function performed by the microprocessor 250. A counter 275 divides the master clock frequency as output from the microprocessor 250 to a compatible clock frequency for use with transmission and reception of data via USART 270. Programmed functions which are performed by the processor 250 in conjunction with stored instructions and user input data can include system configuration control, task sequencing for controlling the PCEs, communications linkage and protocol, user interface, diagnostics, archiving, and other features and functions as desired or needed. Referring to FIG. 5, a detailed schematic of the keyboard 210 of FIG. 3 is shown. The intercoupling of the keyboard 210 to central processing unit 250 is shown, illustrating the correlation of pin assignments from matrix wires of the keyboard matrix 210 to the corresponding pins of the microprocessor 250. Referring to FIG. 6, the display 220 of FIG. 3 is shown in electrical schematic form. The intercoupling of the display 220 to the microprocessor 250 is shown, illustrating the correlation of pin numbers of the display subelements 221 and 222 to the pin coupling designations of the microprocessor 250 (designated integrated circuit U1). The environmental control unit 110 has the capability of separately addressing a plurality of remote peripheral control elements via the modular communication interface means 100. In the illustrated embodiments of FIGS. 4-6, the environmental control unit can separately address 128 remote elements via modular communications interface means 100. This capability can be easily expanded by proper selection of microprocessor and memory. Utilizing the embodiment illustrated in FIGS. 4-6, the environmental control unit can address up to 512 remote modular communications interface means 100. In the illustrated embodiment, the remote modular communications interface means 100 (MCI) are petitioned into 28 sensor units and 100 controller units. However, other partitions can be chosen and configured. The illustrated environmental control unit (ECU) senses and controls functions within a single zone. However, the environmental control unit may alternatively sense and control functions and values in a plurality of zones. When a plurality of zones are being monitored and controlled, a separate point light display (LED) can be used to denote which zone the currently displayed data represents. Heating, cooling, and set point stages are programmed in accordance with keyboard entries. A stage is a type of operation based on the status of sensors and the current operational mode of the system. Each stage represents a priority level of operational protocol for the system, and is utilized in selecting and implementing task scheduling. The number of stages which the system can handle is flexible, according to user definition. The illustrated embodiment of FIGS. 4-6 provide a maximum of 9 stages. However, with appropriate selection of central processing unit and memory, a greater number of stages can be utilized. The temperature thresholds for each stage are entered via the keyboard. Additionally, addresses for each remote peripheral control element (equipment) to be controlled during each stage is entered via the keyboard. Temperature thresholds, including set point values, can be entered in either Fahrenheit or Celsius denominations. A number of additional functions can be performed by the environmental control unit. An outdoor temperature override senses the outside temperature and causes changes in the indoor temperature/stage relationships to be effected by external temperature changes. Also, the temperature hysteresis associated with each stage transition can be taken into account as a processor function (in the processor software). In the illustrated embodiments of FIGS. 4-6, the temperature hysteresis is equal to one degree Fahrenheit. Other values of temperature hysteresis can be selected by means of appropriate processor software. Capability can be provided for manual override of preprogrammed functions, wherein the system operates completely under manual control from the keyboard 210. A dehumidification function can be selected by the user, and is programmed from the keyboard. The parameters to be entered can include the time to begin the cycle, the duration of the cycle, and states to occur simultaneously during the cycle. Where a humidistat is utilized, automatic dehumidification can be provided. For example, when the control sequence being performed under processor 250 control is at the appropriate set point stage, and the humidity exceeds the desired level as determined by the humidistat in accordance with user provider stored data, the environmental control unit switches the system to a dehumidifier stage. However, in the illustrated embodiment, temperature control will override the dehumidification process, as this is deemed generally a more critical factor in greenhouse environmental control. Equipment which is to remain idle when the system is operating under night conditions can be so specified when the system is initially programmed. Thus, the equipment to be locked out during a particular stage at night is specified from the keyboard by the operator. A photocell can be utilized to control the day/night points and corresponding temperature controlled stages of the system. Additionally, a time delay variable can be entered from the keyboard to take advantage of solar gain after dark, and to minimize the solar loss after daylight. Furthermore, a rain override function can be provided to protect against excessive rain entering the controlled environment through open vents. When rain crosses the rain sensing device, a signal is output to the processor which causes the temperature control to be overriden, resulting in the selective closing of the vents to a predetermined position. The vents are closed to the predetermined position only if the vents are open more than the predetermined position. The predetermined position may be specified (is programmable) via the keyboard 210. The system functions described herein can be added to, or deleted from, according to system needs. This may be done by appropriate selection of central processor, memories, remote sensors, and equipment, and by appropriately programming the processor system to selectively control equipment responsive to said sensors. An important functional feature in greenhouse environmental control is vent control. A stand alone vent control system is shown in FIGS. 7-9. In the stand alone vent control system, a vent control unit 300 performs a subset of the functions and features performed by the environmental control unit as discussed above. Referring to FIG. 7, a stand alone vent control system is shown in block diagram form. A vent control unit 300 is coupled via a modular communications interface means 100 to a power transmission line 305. A temperature aspirator (temperature sensing means) 320 is coupled to an associated modular communications interface means 100 which is coupled to the power transmission line 305. Upon interrogation of the temperature aspirator 320 by the vent control unit 300, a digital word representing the current indoor temperature is transmitted from the temperature aspirator 320 via the modular communication interfaces 100 to the vent control unit 300. A vent motor actuator unit 310 is coupled to an associated modular communications interface means 100 which is coupled to the power transmission line 305. The vent motor actuator unit 310 interfaces with a vent motor (not shown), positional limit switches, torque overload sensor switches, and a vent opening detector. The vent control unit 300 transmits control signals via the modular communications interface means 100 to the vent motor actuator unit 310 responsive to the sensed temperature signal received from the temperature aspirator 320. The operation of the vent motor actuator unit is discussed in greater detail with reference to FIGS. 11-13. Referring to FIG. 8, an alternative embodiment of the stand alone vent control system is shown, differing from that of FIG. 7 in that the temperature aspirator (sensor) 320 is directly coupled to the vent control unit 300. Communications between the vent control unit 300 and motor actuator unit 310 is still accomplished via modular communications interfaces 100 and over the power transmission line 305. Referring to FIG. 9, a detailed block diagram of the stand alone vent control system of FIG. 8 is shown illustrating functional features of the system. The vent control unit 300 is shown with a front panel display and switches, including alphanumeric display 329, display indicator lights 331, 332, 333, and 334, selection switch 335, on/off switch 336, auto manual selection switch 337, manual temperature selection means 338, and manual adjust/set selector 339. The vent control unit 300 contains a processor and memory, an analog to digital converter, and a timer counter, as illustrated. In the illustrated embodiment of FIG. 9, all of these features are within a microcomputer such as an Intel 8022 microprocessor system. This microprocessor contains 2 kilobytes of ROM, 64 bytes of read-write memory, an analog to digital converter, a central processing unit, a timer and counter, and multiple input, output, address, and data ports. Alternatively, other processor means and memory means could be utilized, and external analog to digital converters and timer counters could be utilized, or may be included within the selected processor system. For example, the processor system discussed with reference to FIGS. 4 through 13 could be utilized. The motor control communications output from the processor 340 is coupled to a modular communications interface means 100 which may form an integral part of the vent controller unit 300 or may form a separate system to which the motor control outputs of the vent control unit are coupled. The modular communications interface 100 converts digital data to a form acceptable for communications over power transmission lines, and converts data received from power transmission lines back to digital data format for use by the digital system of the vent control unit and of the peripheral control elements. The temperature sensor 320 provides an analog signal, in the illustrated embodiment, which is coupled to the vent control unit 300, as shown in FIG. 8. The analog value output of a temperature sensor 320 is coupled to the analog to digital converter of the processor system 340, where the analog value is converted to a digital value for use by the processor system. Alternatively, the temperature sensor could provide a direct digital output, or the analog to digital converter could be a separate system from the processor subsystem 340. Referring to FIG. 10, a centrally controlled vent control system is shown, utilizing an environmental control unit in the place of the vent control unit. An environmental control unit 350 provides the central control processor for the system. Communications to and from the environmental control unit 350 is via a modular communications interface means 100 and therefrom over the power transmission line 355. The communications from the environmental control unit 350 are coupled via the power transmission line to a second modular communications interface 100b which provides bidirectional communications interface between the power transmission line and a peripheral control element 360. The peripheral control element 360 can be a vent control unit, or may be a stand alone digital logic or processor based system, or may be an integral part of a motor actuator unit 365. A temperature sensor 330 outputs its temperature sensed signal to the peripheral control element 360. The peripheral control element 360 detects when a predefined address has been received via modular communications interface means 100b, and appropriately couples signals either to or from the temperature sensor 330 or the motor actuator unit 365. The motor actuator unit 365 is coupled to a motor and gearhead assembly 370 and to sensor 375. The motor actuator unit provides direction and speed control signals to the motor 370 responsive to received command signals from the environmental control unit 350 via the peripheral control element 360 and modular communications interface means 100b and 100. The speed and direction of the motor of assembly 370 is controlled by the motor actuator unit 365 responsive to the outputs received from the sensor 375 and the control signal received from the environmental control unit. Referring to FIG. 11, a vent motor actuator unit 400 is shown with sensor and motor interfaces. The vent motor actuator unit 400 is coupled to a vent proportional opening detector 410, which provides an output to the vent motor actuator unit 400 representative of the proportional opening of the vent. Vent override sensing means, such as switches 420, provide full closed and full open output signals to the vent motor actuator unit 400 representative of the fully closed or fully opened position of the vent. A modular communications interface means 100 is either included integrally within the vent motor actuator 400 or may be an external system coupled to the vent motor actuator unit. Communications between the vent motor actuator unit 400 and the vent control unit of FIG. 7 or environmental control unit of FIG. 10 is accomplished via respective modular communications interface means 100. The respective control unit provides control signals to the vent motor actuator unit. The vent motor actuator unit 400 provides motor control outputs, forward control and reverse control (corresponding to vent open and vent close commands) to the motor and gear assembly 440, which are responsive to the control signals received via the modular communications interface means 100, and responsive to the full open and full closed signals. The full open and full closed signals provide a system override feature whereby the control signals received via the modular communications interface means 100 are overriden responsive to in response to either of the full open or full closed signals. The motor control signals (vent open and vent close) are responsive to the control signals received from the central control unit (ECU or VCU) via the modular communications interface, and to the vent proportional opening signal, vent closed and vent full open signals. The status of the fully closed and fully open signals, vent proportional openings signal, can alternatively be communicated to the vent control unit (or environmental control unit) from the vent motor actuator unit via the modular communications interface 100. The controller (whether it is a vent control unit or environmental control unit) performs a number of specific functions and features. First, the opening of the vent is controlled in discrete steps. In the illustrated embodiment, the vent opening is a function of the temperature difference between a set point and the measured indoor temperature (actual). The relationship between the vent opening, temperature differential, and stage, are preprogrammed and can be modified from the keyboard of the vent control unit (or environmental control unit). Numerous preset vent positions can be programmed into the system, such as close (0% open), crack (5% open), 25% open, 50% open, 75% open, and fully open. Alternatively, more, less, and different percentage open positions may be selected (programmed). The vent override limit switches 420 detect the full open and full closed positions of the vent. When one of these limit switches is triggered, a corresponding output signal is activated, which is transmitted to and sensed by the vent motor actuator unit 400 which then initiates a command to shut off the motor of assembly 440. Excessive torque is sensed by a torque overload sensor 430. Upon indication of torque overload, by either a forward or a reverse torque overload signal, the vent motor actuator unit 400 (or environmental control or vent control unit where appropriate) initiates a command to shut off the motor. The percentage opening of the vent for a particular setting (e.g., vent crack=5% nominally) can be controlled on the basis of a particular stage which the system is in, the actual temperature and/or the time of day. The vent opening option can also be controlled manually, such as manual control of the crack option. The vent control unit (or environmental control unit) can be programmed to insert a time delay, such as ten seconds, between the time the motor is shut off and the time it is started again. The length of this delay can be determined by appropriate programming. The vent motor actuator unit 400 provides an interface between the environment control unit or vent control unit and the motor/gear assembly 440 of a vent. The vent motor actuator unit 400 can be a stand alone product which can be mounted physically in the vicinity of the vent assembly. For example, it can be an enclosed unit with an on/off switch and an indicator light. Referring to FIG. 12A, a detailed block diagram of the system of FIG. 11 is shown. For example, the diagram of FIG. 12 can represent a printed circuit board block layout drawing. Before discussing the specifics of the vent motor actuator unit components, as shown in FIGS. 12 and 13, a number of specific features of the vent motor actuator unit shall be discussed. The inputs and outputs of the vent motor actuator unit consist of the AC power line 450 (110/220 volts AC), 110/220 VAC vent motor power connection 460, and low voltage wires 465 from the vent full open/closed limit switches and vent proportional opening indicator. In the illustrated embodiment of FIG. 12A, the modular communications interface means 100 is built into the vent motor actuator unit. Vent override switches 420 of FIG. 11, provide detection and signals indicative of the vent full open and full closed positions. The signals representing vent full open and vent full close positions are coupled to the vent motor actuator unit via wires 465. When either a vent full open or vent full closed signal is received, the motor controlled by the vent motor actuator unit 400 is turned off. Similarly, when torque overload is sensed, the motor is turned off. The vent proportional opening detector 410, in the illustrated embodiment, determines the degree of vent opening based on counting the teeth in the rack and pinion assembly comprising a vent open/close drive assembly. A photo emitter and detector pair can be utilized to count the teeth in the rack and pinion assembly. Only the change in status of the photo detector output is stored within the vent motor actuator unit 400. This change in status is coupled to the vent control unit or environmental control unit which contains a counter to maintain an accurate positional status indication. The counter can be zeroed and the vent fully closed to initialize a zero reference position. Thereafter, the number of teeth passing the photo sensor as compared to the total number of teeth comprising the rack will equal the percentage that the vent is open. In the illustrated embodiment, two messages must be received from the vent control unit or environmental control unit prior to activating reversal in the vent opening. Referring again to FIG. 12A, the vent motor actuator unit 400 is further comprised of a power supply 455 which is coupled to the main power wires 450 and provides a digital logic voltage supply to the remainder of the vent motor actuator unit components. Communications between the modular communications interface means 100 and the rest of the vent motor actuator unit is accomplished via USART device 458 which is coupled to processor system 462. The low voltage sensing lines 465 are coupled to the motor control assembly and therefrom to the processor system 462. Vent motor actuator unit 400 address selection and identification is selected and programmed via address select switches 468 using I/O expansion device 469. Alternatively, where the processor system 462 has adequate numbers of inputs, the I/O expansion device 469 is not required. The processor system 462 outputs vent open and vent close control signals to control the motor and gear assembly 470. The vent open and vent close signals are output from the processor 462 to a motor control assembly 470 and therefrom to the motor via power wires 460. Referring to FIG. 12B, a detailed electrical schematic of the vent motor control assembly 470 of FIG. 12A is shown. The power line 450 is coupled to a power supply 1210 which provides regulated, 1214, and unregulated, 1212, DC voltage outputs. The power line 450 is also coupled to switching means, 1230, (such as a solid state relay), to electronic torque overload sensing means 1220, and to power switching network means 1240. The torque overload sensing means 1220 is comprised of current sensing means coupled to the power line 450 and senses the current provided to the motor unit 1250 via switching means 1230 and power switching network means 1240. When current is sensed above a predefined threshold, a torque overload signal is output to the processor system (462 of FIG. 12A) and forces the drive to the motor 1250 to be shut off. Alternatively, torque overload sensors can be placed in the motor means 1250, and a torque overload signal is output to the low voltage lines 465, and therefrom to the processor 462. The power supply 1210 additionally couples a transformer isolated AC signal, which tracks the power line AC signal, to a zero crossing network 1260. When a zero crossing is detected, the network 1260 outputs a signal 1261 which is coupled to the clock input of a latch 1270, such as an SN7474 D-type flip-flop. The output of latch 1270 is coupled to the control input of the switching means 1230, and when active, causes the switching means 1230 to couple one phase of the AC power line 450, as output 460C, to one side of run winding 1251, and to one side of power switching network 1240. The other side of run winding 451 is directly coupled to the power line 450. The output of the latch 1270 is also coupled to one input each of NAND gates 1281-1284 of control network 1280. The forward and reverse motor control signals are each coupled to one input of exclusive OR gate 1285 which has its output coupled to the data input D of latch 1270. The exclusive OR gate 1285 in conjunction with latch 1270 enables an output of an active signal from the latch 1270 only when one or the other of the motor control signals is active, but not when both are active. The forward motor control signal is also coupled to the other input of each of NAND gates 1281 and 1282 while the reverse motor control signal is also coupled to the other input of each of NAND gates 1283 and 1284. The NAND gates 1281-1284 provide logic decoding of the motor direction control signals to effectuate proper activation and selection of switching paths within switching network 1240. The output from NAND gates 1281, 1282, 1283, and 1284, respectively, are coupled via current limitting resistors to the control inputs of triacs 1241, 1244, 1242, and 1243, respectively. The switching network 1240 outputs are power signals 460B and 460A which are coupled to the starter winding 1252 of the motor 1250. The motor 1250 is activated when both the start and run windings, 1252 and 1251, respectively, are activated. The direction of motor movement is controlled by the starter winding 1252, which is controlled by the switching network 1240. When triacs 1241 and 1244 are on (active) and triacs 1242 and 1243 are off, and switching means 1230 is on, the motor is driven in a forward direction. Conversely, when triacs 1242 and 1243 are on, triacs 1241 and 1244 are off, and switching means 1230 is on, the motor is driven in a reverse direction. In the illustrated embodiment, the outputs of NAND gates 1281-1284 are optically isolated from the inputs of triacs 1241-1244 by optical isolators 1245-1248. The rack tooth sense input, 465D, indicates movement of the vent along its rack and pinion assembly. The processor 462 is coupled to the rack tooth sense input signal 465D, and counts the rack tooth sense signals to determine the percentage opening of the vent. A opto-reflective sensor 1291 mounted in the pinion assembly senses passage of a tooth of the rack and pinion assembly by the sensor. A level shift buffer 1290, within the assembly 470 is coupled to the opto-reflector assembly and provides as its output the rack tooth sense signal 465D responsive to the opto-reflective sensor. A full open and full closed limit switch, 1295 and 1296 respectively, are located on the pinion assembly for the vent. The switches 1295 and 1296 are coupled to exclusive OR gates 1297 and 1298, respectively within the assembly 470, which provide debounce and buffering. Full open limit and full closed limit signals are output from gates 1297 and 1298, respectively, to the processor 462. If either the full open or full closed limit signals are active, the vent motor is shut off. Referring to FIGS. 13a-c, a detailed electrical schematic diagram of the processor system 462, USART transmitter system 458, I/O expansion device 469, and address select switches 468 is shown in detailed schematic form. Any microcomputer can be used, such as an independent microprocessor with separate read only and read-write memories or other type of processor system having memory and I/O. In the illustrated embodiment, the Intel 8748 microprocessor (or 8048 microprocessor) system 500 is utilized as processor system 462 having on board read only memory and read-write memory. A plurality of sensed inputs are coupled to the processor 500 via its I/O ports. Device address selection is accomplished via switches 502, 503, 504 and 505 coupled to I/O expansion device 510, an Intel 8243 in the illustrated embodiment. As dicussed above, the I/O expansion device can be eliminated where an appropriate processor is chosen. The I/O device 510 is also coupled to the processor 500 for coupling address selection information thereto. The processor 500 is additionally coupled to the USART 458. The USART 458, as shown in FIG. 13b, is comprised of a universal synchronous asynchronous transmitter 520, an Intel 8251a, in the illustrated embodiment, and a counter circuit, a TTL SN 7493 integrated circuit, 525. The counter circuit 525 divides the master clock frequency received from the processor system 500 and provides suitable clock frequencies to the USART 520. The same electronics of FIGS. 13a-b can be utilized in the peripheral control elements for outdoor and indoor aspirators (temperature sensors), with the addition of an analog to digital converter and temperature calibrator as shown in FIG. 13b. As shown in FIG. 13b, the data bus signals denoted D, from the processor 500 are coupled to A to D converter 530, an ADC080X (such as is available from Analog Devices, Texas Instruments, etc.) but may alternatively be other types of analog to digital converters. A thermistor, 535, a National Semiconductor LM 235A in the illustrated embodiment, is coupled to appropriate biasing circuitry which is then appropriately calibrated to achieve proper temperature calibration. The output from the thermistor 535 is coupled to the A to D converter where the analog voltage from the temperature sensor is converted to a digital signal equivalent which is coupled to the processor 500 via the bus designated D. Referring again to FIG. 1, the interaction of the environmental control unit 110 with the peripheral control elements 120, 130, 140, 150, 160, 170, 180, and 190 via the modular communications interface means 100 will now be discussed in greater detail. The environmental control unit 110 interfaces with each sensing peripheral control element (such as wind sensor 120, rain sensor 130, indoor temperature aspirator 170, outdoor temperature sensor 180, humidistat 190, and photocell 150) according to a predefined protocol. The protocol utilized in the illustrated embodiment is as follows. First, a read command is output from the environmental control unit to each of the sensing units or only those sensing units desired, periodically. The rate of interrogation, i.e., the cycle time, is only limited by the speed of the processing units within the environmental control unit and peripheral control elements, and the communications transmission speed of the selected modular communications interface means. Typically, the sensing units are interrogated once every fraction of a second or few seconds. The modular communications interface means associated with each peripheral control element sensing unit receives the read command signal output from the environmental control unit and either the modular communications interface means or the peripheral control element has means to decode an address associates therewith to determine if that particular sensor is being addressed. The addressed sensor transmits back to the environmental control unit appropriate data regarding the status of the sensor. The modular communications interface means 100 associated with the addressed sensor transmits the data signal via the power transmission line back to the modular communications interface means 100 associated with the environmental control unit 110. Modular communications interface means 100 associated with the environmental control unit 110 decodes the transmitted data and provides it in digital form to the environmental control unit for processing. The environmental control unit thereupon updates its file for the sensor interrogated. The environmental control unit updates its file for each sensor as that sensor is interrogated and reported. This protocol can also be utilized with the vent control unit 300 as described with reference to FIGS. 7-9. However, the vent control unit typically interfaces only with the temperature aspirator unit 170, with or without respective modular communication interface means depending upon the respective locations of the temperature aspirator 170 and the vent control unit. The temperature aspirator 170 draws air through from ambient surroundings within the indoor environment being controlled. A temperature sensor provides an indication of the ambient air temperature which is drawn through the aspirator. The environmental control unit 110 (or the vent control unit in a stand alone configuration) interfaces with the temperature aspirator 170 through modular communication interface means 100. Upon interrogation and proper address decode, the temperature sensor within the temperature aspirator responds to the interrogation with a digital word representing the current indoor temperature. As discussed above, the environmental control unit 110 then updates its file for the temperature aspirator accordingly. The outdoor temperature sensor 180 provides an indication of the outdoor temperature. The environmental control unit 110 interfaces with the outdoor temperature sensor 180 via respective modular communications interface means 100. Upon interrogation and proper address decode, the temperature sensor 180 responds by outputting a digital word representing the current outdoor temperature to the environmental control unit. The environmental control unit then updates its outdoor temperature sensor file accordingly. The photocell sensor 150 provides an indication of the light level at the location of the photocell. Environmental control unit 110 interfaces with the photocell sensor 150 via respective modular communications interface means. Upon interrogation and command, and proper address decode, the photocell sensor 150 responds with a status bit (logic 1 or logic 0) indicating the present state of the sensor. The environmental control unit 110 then updates its photocell file accordingly. If there are more than one of a given type sensor, only the appropriate file is updated. The wind sensor 120 provides an indication of wind velocity, and can also be utilized to indicate wind direction where desirable. The environmental control unit interfaces with the wind sensor 120 via respective modular communications interface means 100. The wind sensor compares the sensed wind velocity with a predefined threshold level. Upon command and proper interrogation, and proper address decode, the wind sensor 120 responds by outputting a status bit (logic 1 or 0) indicating whether the current state of the sensor is above or below the predefined threshold. The wind sensor 120 can give a proportional reading, and utilizing an A to D convertor and a modular communications interface means 100 can communicate proportional data back to the environmental control unit 110. In the illustrated embodiment, the rain sensor 130 detects and provides an indication of outside moisture. The environmental control unit 110 interfaces with the rain sensor 130 via respective modular communications interface means 100. Upon proper command and interrogation, and proper address decode, the rain sensor 130 responds by outputting a status bit (logic 1 or 0) indicating that the current sensed state of the sensor is greater than a predefined threshold. Alternatively, proportional, relative, or absolute value sensing and transmission can be provided. A humidistat 190 can be provided in the system to detect the humidity level, either in absolute terms, or in relative terms above or below a set point. The environmental control unit 110 interfaces with the humidistat via respective modular communications interface means 100. Upon proper command and interrogation, and proper address decode, the humidistat responds by outputting a status bit (logic 0 or 1) indicating whether the humidity is above or below the set point. Alternatively, other data regarding humidity can be provided and transmitted. Communications between the environmental control unit and each remote peripheral control element is via respective modular communications interface means 100. There are two communications protocols which can be utilized in the illustrated embodiment. First, the transmission can be unidirectional from the environmental control unit 110 to the addressed unit to be controlled or sensed. The environmental control unit 110 transmits the current desired status bits to each functional unit or units, one transmission at a time, once every second or fraction of a second (depending on the cycle time). In a cycle in which the command from the environmental control unit is rejected by the peripheral control element, no action is initiated by the addressed function until a correct message is received. Alternatively, the transmission between the environmental control unit 110 and the addressed remote peripheral control element or elements can be bidirectional. In this mode, command is transmitted by the environmental control unit 110 to a remote unit (peripheral control element), via respective modular communication interface means, and, if properly decoded and accepted, is acted upon by the addressed remote unit or units, and a status bit activated, which is output (transmitted) to the environmental control unit 110 via the modular communications interface means. In this mode, the command continues to be retransmitted at predefined time intervals until a positive response is received from the addressed remote unit. If a positive response is not received after a predefined number of transmissions, an alarm routine is engaged by the environmental control unit (a program is actuated) which causes the nonresponding modular communications interface address number to be flashed on the display until it is manually reset by the operator. This bidirectional transmission mode provides fault isolation and can be tied into an alarm system if desired. Many additional functions and features can be added to the environmental control system in the greenhouse control setting. To utilize the central environmental control unit requires that many of these functions be interfaced to the environmental control unit via respective modular communications interface means. These include single speed and two speed exhaust fans, evaporative cooling pumps, unit heaters (both gas fired and steam heaters), and FACT impellers (which can consist of a fan motor and motorized shutter assembly). Referring to FIG. 14, a partial schematic partial block diagram of a single speed exhaust fan interfaced to a modular communications interface circuit is shown. The modular communications interface means 600, as illustrated, contains a switching means 605 for providing a selective coupling. For example, a single relay (e.g. single pole) in the modular communication interface means 600 can be utilized to switch either the line voltage or a control signal. The voltage to be controlled can vary from 24 volts AC to 440 volts AC depending upon the electric service and the type of exhaust fan control utilized. Typically, the power to be switched is approximately 40 watts. A controller circuit within the modular communications interface 600 provides the necessary signal for activating the relay (switch) 605, which thereupon activates the motor 610 to cause the exhaust fan to be turned on. Referring to FIG. 15, a partial schematic partial block diagram of a two speed exhaust fan interface with a modular communications interface system is shown. As illustrated, the modular communications interface means 620 contains two relays (switches) providing double pole switching, which can be independently or simultaneously controlled. Where the selected fan motor 635 has two speeds which must be controlled remotely, two relays 625 and 630, or other appropriate switching means, can be incorporated into the modular communications interface means 620. The same voltage switching combinations are possible as noted above for the single speed option of FIG. 14. The relays are activated by signals from a controller means forming a part of the modular communications interface 620. Where independent control of each relay is desired, two control signals are required from the controller means. Referring to FIG. 16, a detailed block diagram for a single speed exhaust fan controller and modular communications interface means, such as 600 of FIG. 14, is shown with associated components. The single speed exhaust fan modular communications interface means 640 may also be used for an evaporative cooling pad pump or for control of a gas unit heater without a venter. The modular communications interface means 640 is comprised of terminal strips 644 and 647, central processor system 648, address selector 650, power supply 652, transmitter means 654, receiver means 656, signal isolation means 658, and power switching means 660. A cable of wires 665, power transmission line wires, is coupled to the power transmission lines, whether it be single phase requiring only two wires, or 220 volts-two phase or 440 volts-three phase. The voltage and phase of the power transmission line system utilized affects selection of the power supply means 652. The power supply 652 converts the AC power line voltage to DC logic power supply voltage levels for utilization by other circuitry in the modular communications interface means 640. The transmitter 654 and receiver 656 can be coupled to a single phase of the power supply transmission system (or may alternatively be coupled to one some, or all phases of a multi phase power transmission system, depending on the system circuit design utilized). In the illustrated embodiment, the transmitter 654 and receiver 656 are coupled to a single phase power transmission system. The transmitter 654 and receiver 656 are also coupled to a central processing system 648, containing a central processing unit, memory, and input and output ports. In the illustrated embodiment, an 8048 microcomputer (e.g. Intel) is utilized, but other processor systems, whether single chip or multichip, can be utilized as desired in accordance with system needs and cost constraints. The processor system 648 is coupled to an address selection means 650. The address selection means 650 is set to the desired modular communications interface address to which the modular communications interface means 640 is to respond. The receiver 656 converts communications data signals received from the power transmission line via cable 665 to digital signals which are output to the processor system 648. The processor first compares the received address to the preselected address of the address selector 650. If a proper address is selected, then the processor system 648 responds in a proper manner according to a preprogrammed function. When appropriate, the processor system 648 transmits a digital message to the transmitter 654. This message is converted to a form compatible for transmission via the power transmission line and is output as communicated data onto the power transmission line via cable 665. Additionally, when appropriate, the processor 648 provides outputs to the isolation means 658 so as to activate the power switching means 660. In the illustrated embodiment, optically isolated triac drivers are utilized for the signal isolation means 658 and triac switches are utilized in the power switching means 660. The number of triacs and the number of isolators utilized is a function of the number of phases and the AC voltage and current levels being switched. The power switching means 660 is coupled to the incoming power tranmission line via the terminal 644 and cable 665. The switch outputs from the triac switches 660, or other switching means are coupled to the terminal strip 647 and therefrom to cable 670, containing wires which lead to and contact to a remote fan or motor 675. The fan motor 675 can also be an evaporative cooling pad pump, or gas unit heater without venter, each of which typically require less than five amps. However, the power requirements of the load may be adjusted for by appropriate selection of a power supply 652 and switching means 660. Referring to FIG. 17, a dual function low voltage modular communications interface means 700 is shown which may be utilized for controlling a two speed fan, a unit heater with venter, a unit heater with electronic ignition, or a FACT impeller. The dual function low voltage modular communications interface means 700, as illustrated, is comprised of terminal strips 702 and 704, power supply 710, transmitter 715, receiver 720, central processing systems 725, address selection means 730, voltage isolation means 735, and power switching means 740. The power transmission lines 690, whether they be single phase 110 volt, two phase 120 volt, or three phase 440 volt, are coupled to the modular communications interface 700 via connection means 701, such as a multiwire cable. The connection from cable 701 connects to terminal strips 702 and therefrom to the power supply 710, transmitter 715, and receiver 720. The power supply 710 converts the AC voltage to a DC logic power supply voltage utilized for the electronic components within the modular communications interface means 700. Communications signals received from the environmental control unit over the transmission lines 690 are decoded by the receiver 720 and converted to digital signal form. In the illustrated embodiment the transmission and decode are serial in nature. The processor system 725, containing a central processing unit, memory, and input and output ports, in accordance with preprogrammed functions, decodes the received data signals and compares the reconstituted receved address signal to the preselected address signal as set by address selector means 730. If the proper address is decoded, the processor systems 725 responds in accordance with programmed functons. The processor system 725 may be the same processor system as 648 of FIG. 16, programmed differently, or operating off different subportions of a master program. Alternatively, other processor systems can be utilized as discussed with reference to FIG. 16. In a similar manner, as discussed with reference to FIG. 16, where appropriate, the processor system 725 outputs digital signals through the transmitter 715, which converts those signals to proper format and level for power line transmission. The transmitter 715 then outputs the appropriate signals via the connection means 701 back onto the power transmission line 690, where the signals are thereafter received and decoded and acted upon by the modular communications interface means 100 associated with the environmental control unit and are thereafter acted upon by the central control processor of the environmental control unit. Additionally, where appropriate (responsive to the received address and command from the environmental control unit), the processor system 725 provides control outputs representative of the desired power switching states. These outputs are coupled to the inputs of isolation means 735, which in the illustrated embodiment are optically isolated triac isolators. The output from the isolator means 735, corresponding to the control outputs of the processor system 725, are then used to control the switching means 740 to selectively close switches therein. In the illustrated embodiment, triac switches are utilized in the switching means 740 to provide two switching channels. The number and types of triacs are dependent upon the voltage and currents being switched. In the illustrated embodiment, low voltage (e.g. 24 volts AC) signals are coupled from an external low voltage control unit 745 via cable 705 to terminal strip 704 and therefrom to the input of the switching means 740. The output of the switching means are coupled to the terminals 704 and therefrom to the cables 705 back to the low voltage control unit 745. The low voltage control unit 745 selectively switches the power line voltage, or other desired voltage, to the dual speed fan, unit heater with venter, unit heater with electronic ignition, FACT impeller, or other selected equipment. Alternatively, the low voltage control unit can be replaced by a power line control voltage level unit, in which case the inputs to the terminal strip 704 and therefrom to the switching means 740 would be from the power transmission line 690 itself, in a manner similar to that discussed with reference to FIG. 16. As discussed with reference to FIG. 16, the single function modular communications interface means 640 can be utilized to control a single speed exhaust fan, evaporative cooling pad pump, gas unit heater without venter, or other single function devie. However, although the same basic modular communications interface is required for each of these functions, certain applications may require some modifications to the switching means 660 dependent on the power requirements of the motor being controlled. Some pad pump motors can be twice as large as the typical exhaust fan motor. For example, a typical exhaust fan motor is one-horsepower requiring five amps. In some locations, pad pump motors can require as much as ten horsepower motors. Obviously, by selection of high power switching devices for the switching means 660, one system can handle all requirements. However, by appropriate selection of optimally sized switching means 660, the cost can be reduced for those applications requiring less power. As discussed with reference to FIGS. 16 and 17, unit heaters can also be controlled by the single function (gas unit heater without venter) and dual function modular communications interface means. In accordance with the illustrated embodiment, there are at least two types of unit heaters which can be controlled. One is gas fired, and the other is steam or hot water powered. The modular communication interface means of FIG. 17 can accomodate the various options which the gas fired units can present. Simple on-off control requires only one relay (or other appropriate switching means) on the modular communications interface means. Typically, a one-sixth horsepower motor is utilized requiring 120 volts power line voltage to be switched. This application can be handled by the modular communications interface means as discussed with reference to FIG. 16. Where the gas fired heater includes a venter, two relays or switching means are required on the modular communications interface, such as the modular communications interface of FIG. 17. One relay (or other appropriate switch) is required for switching 24 volts AC at two amperes to provide for heat control, in the illustrated embodiment. The second relay (or other switching means) is needed for fan control and must be able to switch 24 volts AC one amp, in the illustrated embodiment. Typically, the heater fan motor will be three-fourths horsepower, 230 volts. The low voltage control unit 745 switches power to the fan motor responsive to the second relay control signal. A gas fired heater having a two stage heater requires three relays on the modular communications interface means. One relay is required for fan control, and the other two for the two stages of heat control. The relays can be solid state, electromechanical or otherwise, as desired. A gas heater with electronic ignition requires two relays or switches on the modular communications interface, such as a system of FIG. 17. One of the relays (switches) is required for gas flow control. The other relay (switch) is required for fan motor control, as discussed above. Referring to FIG. 18, a steam heater low voltage modular communications interface means 800 is shown. The steam heater 850 requires control of a fan and a proportional steam valve. The fan control is based on a simple on/off control which requires only one relay or switching means 845. The proportional steam valve control interfaces with an actuator which is fully open when driven by a first voltage level, three volts DC in the illustrated embodiment, and is fully closed at a second voltage level, six volts DC in the illustrated embodiment, However, in the illustrated embodiment, intermediate voltages of four and five volts DC are also required. The power transmission line 790 (the voltage and phase dependent on the power tansmission system being utilized) is coupled via connection means 801 (such as a cable) to the terminal strip 805 of the modular communications interface means 800. The power supply 810, transmitter 815, and receiver 820 are each coupled to the power transmission line via terminal strip 805. The power supply 810 converts the AC voltage to DC logic power supply voltage levels for utilization by electronic components within the modular communications interface means 800. The receiver converts received communications signals from the power transmission lines to digital signal equivalents, coupling the digital signals to the processor system 825. The processor system 825 contains a central processing unit, memory, and input and output ports. Alternatively, discrete logic can be utilized to perform necessary functions or other types of processor or logic can be utilized. For example, the processor can be an Intel 8048, as described with reference to FIG. 16, or can be implemented by other appropriate processors or logic. The processor compares the received communications address with a preselected address as output from the address selection means 830. The address selection means 830 is preset to the desired modular communcations interface address to which this modular communications interface is desired to respond. Responsive to receiving and decoding appropriate address and command signals, the processor 825 responsively performs respective functions, accordingly, either responsive to a predefined program, or in accordance with other logic control means. When appropriate, the processor 825 transmits digital signals (corresponding to an appropriate response) to the transmitter 815, which converts the digital signals to appropriate form and level for output to the power transmission line 790 via terminal strip 805 and cable 801. Additionally, when appropriate, responsive to received address and command signals, the processor system 825 provides output control signals to select one of four voltage options. The voltage control signal may either be encoded, requiring two signals, or unencoded, requiring four signals. The voltage selection signals are output to the voltage selection means 835 which provide one of the four voltage outputs (3, 4, 5 or 6 volts DC in the illustrated embodiment) on a single actuator output, responsive to the received voltage selection inputs. The actuator output is coupled to the steam heater proportional valve control and provides a drive signal therefore. Additionally, where appropriate, the processor system 825 provides a separate fan control signal output. The fan control signal output is coupled to the voltage isolation means 840, and therefrom to the power switching means 845. The isolation means 840, in the illustrated embodiment, is an optically isolated solid state switching circuit, such as a triac or transistor based switch. The output of the isolation means 840 is coupled to the switching means 845, which can be a relay or triac assembly, or other appropriate voltage switching means. A low voltage control unit 795 provides a 24 volt AC fan control signal, in the illustrated embodiment, via conductor 802 to terminal strip 808 of the modular communications interface 800. This signal is coupled to the input of the switching means 845. The output of the switching means 845 is coupled to a different terminal of the terminal strip 808 and coupled therefrom to the conductor 802 to the low voltage control unit 795. Responsive to the output of the switching means 845, the low voltage control unit 795 selectively switches the power transmission line voltage signals at its inputs to its outputs and therefrom to the steam heater 850 providing fan control. As discussed with reference to FIG. 17, the dual function low voltage modular communications interface means can be utilized for control of the FACT impeller. The FACT impeller can consist of a fan motor and a motorized shutter. The fan motor can be controlled by a simple on/off control which requires one relay or switch on the modular communications interface, the relay or switch having a capacity in accord with the fan motor specifications. The FACT impeller also has a motorized shutter which requires an on/off control signal, thus requiring a second relay or switch on the modular communications interface for the FACT impeller. Referring to FIG. 19, a modular communications interface means for a FACT impeller is shown. The modular communications interface 900 is coupled to the power line 890 by coupling means 895. The coupling means 895 couples the power line to the transmitter-receiver 950 of the modular communications interface 900. Received communication signals are converted to digital signal form which are then coupled from the receiver portion of the transmitter receiver system 950 to the processor system 960 of the communications interface 900. The processor system 960 reconstitutes the received address and command signals, detects and confirms proper address selection for this particular modular communications interface in accordance with the predefined address selection. When a proper address selection is confirmed, the commands received are interpreted and acted upon by the processor system 960. Where appropriate and responsive, the processor system 960 couples a digital signal output to the transmitter portion of the transmitter-receiver system 950, which converts the received digital signal to a form and voltage compatible for transmission over the power line 890 via cable 895. Where appropriate, responsive to a fan motor "on" command, the processor system 960 provides an output signal coupled to first switching means 910 which actuates the fan motor. The switching means 910 can be a relay, or solid state switches, or other appropriate means. Additionally, where appropriate, in response to a properly decoded address and command, the processor system 960 outputs a control signal to a second switching means 920 so as to cause the motorized shutter to be turned on, or off, respectively, according to the received commands. The second switching means 920 can also be a relay, either electromechanical or solid state, or can be other appropriate switching means. Thus, the fan motor and motorized shutter may be individually and selectively turned on and off by the FACT impeller modular communications interface responsive to received commands from the central environmental control unit. Where it is desirable to have a positive indication that the shutter has responded as commanded, a contact switch 940 can be mounted on each shutter, external to the modular communications interface means 900, which, when activated, momentarily closes a circuit. The contact switch 940 is coupled to the modular communications interface means 900 to a status detector circuit 930 within the modular communications interface 900. Upon detection of momentary closure of the contact switch, the status detector 930 couples this status determination to the processor system 960, which in turn transmits the information via the transmitter portion of the transmitter-receiver 950 over the power line to the environmental control unit. If a positive indication is not received from the status detector 930 by the environmental control unit, the environmental control unit causes the appropriate modular communications interface address number of the respective FACT impeller modular communications interface 900 to be flashed on its display until it is manually reset. A single modular communications interface for a FACT impeller, such as 900, can also handle multiple FACT impeller systems. For example, the modular communications interface 900 of FIG. 19 could be expanded to handle tens or hundreds of FACT impeller systems by utilization of appropriate processor system hardware and software and/or output decoders and expanders. However, this is often not practical due to the spacial separation of the FACT impeller systems. Referring to FIGS. 20A-B, detailed schematic diagrams of alternate embodiments of a modular communications interface means are illustrated. Referring to FIG. 20A, a coupling 1005, such as a power connection plug, couples the modular communications interface means to the AC power transmission line. As illustrated, one side of the power line is coupled via decoupling capacitors C-15 and C-16, respectively, to a receiver transformer TM 2 and a transmitter transformer TM 1 respectively. The receiver and transmitter subsections of the modular communications interface means can alternatively be classified as demodulator and modulator sections of the modular communications interface means. The demodulator section of the modular communications interface means is designated 1090 and the modulator section of the modular communications interface means is designated 1095. A connector 1000, a 14 pin socket connector in the illustrated embodiment, provides coupling from the modular communications interface means (sections 1090 and 1095) to the associated processor system of the remote peripheral control element or environmental control unit (or vent control unit). Alternatively, where the modular communications interface means and controller portions are combined in a single system block, such as in the single speed exhaust fan modular communications interface means, the signals from the connector 1000 are coupled directly to that system processor. The processor system couples a transmit data (TXD) signal and a transmit enable (TXEN/) signal to the connector 1000 coupling therefrom to the modulator 1095. Additionally, as illustrated, a ground reference signal is coupled between the connector 1000 and the processor system attached to the connector 1000. Furthermore, a received demodulated data signal (RXD) is output from the demodulator section 1090 via connector 1000 to the associated processor system. The transmit enable control signal TXEN/, is coupled from pin 1 of the connector 1000 to the anode of diode D1. Diode D1 can be a small signal diode, such as a 1N 914, or other device. The diode D1 provides voltage bias level isolation of the TXEN/ signal. The cathode of diode D1 is coupled to one end of a resistor R7 which has its other end coupled to ground, and to one end of base current limiting resistor R8 which has its other end coupled to the base of shunting transistor TS1. When the TXEN/ signal is at a low logic level (active), diode D1 blocks the signal from passing to transistor TS1 (diode D1 is reverse biased). The voltage at the cathode of diode D1 is pulled to ground via resistor R7. The ground potential at the cathode of diode D1 is coupled to the base of transistor TS1 via resistor R8. The ground potential signal at the base of TS-1 causes transistor TS1 to be in a non-conducting off state (for the NPN transistor as illustrated). Thus, the collector of TS1 floats at whatever signal voltage level is present thereupon. The collector of transistor TS1 is coupled to the base of transistor TS2 which provides modulator output drive for coupling the modulator signal onto the power line via transformer TM1 as discussed hereafter. The TXD, transmit data, signal received via connector 1000 is coupled to a voltage controlled oscillator (VCO) 1030 via a control spread network (1010) comprised of resistors R1 and R2 and capacitor C1, and a bias network 1015 as illustrated. The control spread network 1010 fixes the frequency spread between the space (lower frequency) and mark (higher frequency) outputs of the modulator section 1095. For maximum signal to noise ratio of the demodulated signal, the spread should be approximately equal to the digital signal data transmitting rate. The TXD signal is coupled via the control spread network 1010 via biasing network 1015 to the input of the voltage oscillator 1030. The biasing network 1015 has its configuration determined in accordance with the selected voltage control oscillator 1030. The VCO 1030 can be implemented in discrete component or integrated circuit form, such as an LM566 integrated circuit from National Semiconductor and other vendors, or other equivalent circuits. The center frequency of the VCO 1030 is set in accordance with the center frequency control network 1020 comprising resistors R5, R6, and capacitor C3, as is illustrated. The output of the VCO 1030 (pin 3 of integrated circuit 1030 as illustrated) is coupled via coupling capacitor C5 and base current limiting resistor R9 to the base of output drive transistor TS2. Diode D2 provides reverse bias input protection for transistor TS2. When TXEN/ is at an active (low logic) signal level, transistor TS1 is shut off, thereby allowing transistor TS2 to function responsive to the signals as output from VCO 1030. Thus, transistor TS2 is selectively turned on and off responsive to the output of the VCO 1030. When turned on, transistor TS2 causes current to flow through pull up load resistor R10, causing a voltage drop to occur across resistor R10. The center tap and one end tap of transformer TM1 are coupled across resistor R10. Capacitor C6 is coupled across the two end points of the primary winding of transformer TN1 forming part of the tuned circuit of the transformer TM1. In the illustrated embodiment, the transformer, TM1, and TM2, have tuning slugs to allow for tuning of center frequency selection and to provide for impedance matching of the secondary to transformer TM1 and primary of transformer TM2 to the power transmission lines via coupling means 1005. The sensed voltage change across resistor R10 is transformed and coupled in the primary of transformer TM1 to the secondary coil, performing a step down in voltage function and a step up in current function in the transformation process. The transformers TM1 and TM2 form signal tuned filters, in conjunction with associated resistance and capacitance components. When the TXEN/ signal is in an inactive signal level (logic high), transistor TS1 is turned on, thereby shunting the base of transistor TS2 to a ground (or nearly ground) voltage level. This causes transistor TS2 of be shut off, disabled, thereby preventing any voltage drop across R10, and inhibiting any signal transmission via transformer TM1. Thus, with the transmitter disabled, TXEN/ at an inactive signal level, the driver transistor TS2 of the modulator 1095 is disabled so as to be non-responsive to VCO 1030. The VCO 1030 converts data from TTL level data signals at connector 1000 to frequency shift keyed signals, above and below a center frequency. The binary logic levels of the TXD signal are converted from the logic 0 and logic 1 voltage levels to frequency tones above or below a carrier center frequency by a predefined spread frequency. The switching between the two frequencies is at the rate of the data input, providing asynchronous transmission capability. As discussed above, the center frequency of the VCO is determined by the center frequency control network 1020. The spread (frequency shift from the center carrier frequency) between the space (logic 0) equivalent and mark (logic 1 equivalent) signals is determined in accordance with the component values of the control spread network 1010. The spread is also a function of the drive provided at the input to the VCO, pin 5 of the illustrated embodiment. Thus, The biasing network 1015 is also a factor affecting the spread. It is desirable to maximize the signal to noise ratio of the signal as output from the modulator section. It has been found the optimal noise protection is obtained when the modulation index is kept close to 1 (unity). The modulation index equals the spread between the mark and space frequencies divided by the data rate of transmission. Thus, by setting the spread between the mark and space frequencies, equal to the data rate of transmission (as received from the processor system via the connector 1000), noise rejection can be optimized. Power supply voltages are provided to the modulator and demodulator sections 1095 and 1090 respectively, from the associated system (e.g. the processor system) via connector 1001 of 14 pin socket connector in the illustrated embodiment. Alternatively, where the modulator communications interface means forms a stand alone control, power supply voltages may be generated and coupled directly within the modulator communications interface means system. The demodulator (receiver) system recovers the transmitted data signals from the power transmission line and converts the frequency shift keyed signals back to binary logic level data signals (TTL signals in the illustrated embodiment). The receiver transformer TM2, has its primary coupled to the power transmission line 1005 for receiving frequency shift signals therefrom. One end of the primary of TM1 is coupled directly to one leg of the power transmission line, and is coupled via decoupling capacitor C15 to the other leg of the power transmission line. Capacitors C15 and C16 act as filters to shunt out the 60 Hz frequency components of the power transmission line from the received signals. The receiver transformer TM2 is, in the illustrated embodiment, a tuned filter (about the center frequency) for maximizing the signal to noise ratio of the demodulated output signal (as output from pin 7 from demodulator means 1050). Additionally, transformer TM2 performs a voltage step-up function between primary and secondary. More specifically, the voltage appearing across the primary of TM2 is step up voltage coupled to the secondary across the center tap, pin 2, and one end tap, pin 1, of the secondary of transformer TM2. Pins 1 and 2 of the secondary transformer TN1 are coupled to the plus and minus differential inputs of the differential amplifier means 1040, coupled to pins 2 and 4, respectively. In the illustrated embodiment, the differential amplifier means 1040 is a two stage differential amplifier, such as an LM3046 or equivalent. Capacitor C7 across the two end points of the secondary of transformer TM2 forms a part of the tuned filter circuit of the transformer TM2, which in conjunction with the tuning slug, 1006, provides the resonant tank circuit for the tuned filter transformer TM2. Additionally, resistor R11 and capacitor C8 effect the tuning of the transformer TM2. The amplifier 1040 shapes, amplifies, and provides impedance transformation of the differentially input signal, and provides as an output a symmetrical square wave with output levels compatible with the requirements of the phase lock demodulator 1050 to which the output is coupled. Resistors R12 and R13 form an input biasing network, adjusting the bias level for the signal input coupled into pin 2 of the differential amplifier 1040. Resistors R14 and R15, respectively, provide current source limiting for the first and second differential input stages, respectively, coupling to the common emitter points of the first and second differential input stages. Resistors R16 and R17 are load bias resistors, coupling to the collectors of the first stage input transistors, respectively. Resistor R18 forms an output load resistor, coupled to the collector of the second (output) transistor of the second differential stage of the amplifier 1040. The output from amplifier 1040, at pin 8 of amplifier 1040, is coupled via the coupling and input level control network 1045 to the mixer input (pin 2) of phase lock demodulator 1050. The phase lock demodulator 1050 can be discrete circuitry or an integrated circuit VCO system providing phase lock demodulation, and can also provide carrier detection. The network 1055, comprising resistor R10 and capacitor C10 are filter determining components which are coupled to the tank inputs of the lock detect filter (carrier detect) inputs (pins 3 and 4) of demodulator 1050 as illustrated. The phase output of the locked detect filter appears at pin 5 of the demodulator 1050, in the illustrated embodiment, and is not utilized outside the demodulator 1050 in the illustrated embodiment. An inverse detector output appears at pin 6 of the illustrated embodiment. The center frequency of the phase lock loop voltage controlled oscillator of the demodulator 1050 is set in accordance with the selected timing capacitor C11 coupled across pins 14 and 13 of the demodulator circuit 1050. A loop phase detect filter is provided with a time constant set according to timing network 1060 as coupled across pins 11 and 2 of the demodulator 1050. The network 1060 aids in the control of the center frequency F C of the oscillator of the demodulator 1050, and also forms a filter network to remove the carrier and thereby aid in detection of data. The output of the loop phase detector apears at pin 11 of the demodulator 1050, as illustrated, and is coupled via current limiting resistor R25 to one input, pin 8, as illustrated, of a comparator within the demodulator 1050. The other input of the comparator is internally coupled to the reference voltage as output at pin 10, as illustrated. The output of the comparator appears at pin 7, and is commoned to pin 6 and coupled to the input of a voltage level shifting interface network 1065 and is coupled via positive feedback resistor R26 to the comparator input at pin 8. Resistor R26 and capacitor C14 form a comparator feedback network between the output at pin 7 and the input at pin 8. The comparator output at pin 7 is coupled to level shifting network 1065, which converts the demodulated output to a compatible logic voltage level, TTL voltage levels in the illustrated embodiment, in conjunction with transistor TS3. Transistor TS3, an NPN transistor in the illustrated embodiment, is selectively turned on (to a conducting state) responsive to the output from the demodulator 1050. The collector of transistor TS3 is coupled to the RXD pin of connector 1000, which couples the signal received as RXD to the processor system. In the illustrated embodiment, the RXD signal is pulled up to five volts via a pull up resistor in the processor system, such as a 10K Ohm pull up resistor. When the transistor TS3 is on, the RXD signal is at ground voltage potential, as the collector is shunted to the emitter voltage level (the emitter being coupled to ground). When the transistor TS3 is off, the transistor is not conducting, and the voltage at the collector of transistor TS3, is floating, i.e. is at whatever voltage level is otherwise coupled to the collector. As discussed above, where a pull up resistor to five volts (logic one in a TTL system) is coupled to the collector of TS3 via connector 1000, the signal level of RXD in the transistor TS3 off condition is a five volt (logic 1) signal. Thus, logic 0 (0 volts) and logic 1 (5 volts) signals are provided as the decoded output of the frequency shift keyed demodulator section 1090. Referring to FIG. 20B, an alternate subsystem 1100 of the modulator of FIG. 20A is shown. Resistors R30-R35 and transistors TS3 and TS4 form a buffer-driver amplifier, amplifying the TXD (transmit data) signal from connector 1000 and coupling the amplified signal to the input, pin 9, of voltage controlled oscillator (VCO) 2000. The VCO 2000, as illustrated can be an EXAR XR2207, or alternatively can be any other type of VCO if appropriate support circuitry is provided. The VCO free-running frequency is determined by appropriate selection of a timing capacitor C21. The upper sideband frequency is determined by selection of resistor R39 and R41. The lower sideband frequency is determined by selection of R40. Resistors R36 and R37 provide input bias control. The frequency shift keyed signal is output from pin 13 of VCO 2000 and is coupled via capacitor C5 and resistor R9 to transistor TS2 for coupling to the power line 1005 and discussed with reference to FIG. 20A. While the modular communications interface means has been discussed with reference to a particular embodiment, other embodiments may also be used, utilizing different communications protocols and/or similar or different circuitry to implement the system. In an alternate embodiment, the modular communications interface means provides communications among associated peripheral control elements and control units (environmental control unit or vent control unit) via radio frequency communication, thereby obviating the need for any communications wiring, either power transmission line or dedicated communications lines. To utilize radio frequency communication instead of power line based communication, some of the oscillators and transmission frequencies must be changed, such as VCO 1030 and demodulator 1050. For example, power line communication can be implemented with a center frequency ranging from tens to hundreds of kilohertz. Radio frequency transmission typically utilizes a carrier (center) frequency of tens or hundreds of megahertz. However, conceptually the modular communications interface means would remain the same. In the illustrated embodiments of FIGS. 20A, 20B the demodulator 1050 is an Exar-XR2211 integrated circuit. Alternatively, other commercial integrated circuits could be utilized such as an LM566, LM564 or other VCO based system. Referring to FIGS. 1 and 2, a communications network is shown. The communication network facilitates the transfer of environmental variables from remote sensing elements to the central controller, and the transfer of command data from the central controller to remote actuator elements. Furthermore, such information transfer must be made utilizing techniques which reduce the probability of error and the probability of a missed message to a negligibly low level. All information transfers in the environmental control network are accomplished using digital signaling signalling over the existing 60 Hz AC power wiring of the facility. Digital data, in the form of a serial stream of bits, are transformed into a sequence of radio-frequency tones by a frequency-shift keyed (FSK) data apparatus. These tones are inductively coupled to the power line. In order to minimize noise susceptibility, a sampling detector is used to translate the tones back into digital data. Each remote element, whether a sense element or an actuator element, transmits only in response to interrogation by the central controller. The central controller allocates time slots, each dedicated to communication with a uniquely-addressed remote element. Any number of addresses are possible, with an initial capability of 300 present in the illustrated embodiment. The nature of data transfer is dependent the type of remote element being addressed. For example, in the current configuration, all addresses beginning with "1" are vent motor actuators. Hence, whenever a time slot associated with an assigned vent apparatus is active, the "1" in the address directs the central control computer to first address the unit, wait for an acknowledgement, and then transmit a percentage opening for that particular vent. When the address prefix is "2", the controller sends the address, and subsequently waits for temperature data to be returned from an outdoor temperature sensor. Similarly, a "3" indicates an indoor temperature sensor, which returns both light-level and temperature information. At the end of each time slot, the central control computer addresses a new time slot, checks to see if this time slot has been assigned by the user, and, if so, commences transmission. During this initial transmission, address data is preceded by a "unique word" which serves to synchronize all remote elements, and indicates that some element's address is forthcoming. The remote element whose address follows the unique word then takes appropriate action, while all others go back to waiting for another unique word. When there are multiple network masters (net master), i.e., multiple central controllers, present on the network simultaneously as shown by the phantom master controller 103, no contention problem exists as long as: (1) their respective users assign no remote addresses in common, and (2) the central controllers share a common time slot clock. The latter consideration is of course the more difficult. Since even stable crystal oscillators exhibit drift phenomena, an adaptive time slot synchronization scheme is utilized in the system. In this scheme, each net master continually listens (monitors) for the transmission of the unique word by another net master. If one is detected, the ensuing address information is monitored, giving precise information regarding the state of the time slot clock of the other net master. In an adaptive manner, all net masters count time slots in lock-step with one another. With this communication technique, provision is included for digital data transfer, two-way communication, and multiple net masters. Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as other embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention. ##SPC1## ##SPC2## ##SPC3## ##SPC4## ##SPC5## ##SPC6## ##SPC7## ##SPC8## ##SPC9## ##SPC10## ##SPC11## ##SPC12##

An environmental control system for use in greenhouses or other structures requiring the control of a temperature regulating element in response to sensed temperatures. The environmental control system includes a plurality of sensor elements and actuator elements comprising peripheral control elements each of which communicate bidirectionally with individual communication interface units. A central control processor bidirectionally communicates with another communication interface unit. All of the interface units bidirectionally communicate with each other over fixed AC power lines by frequency shift keying the information onto and from the lines. The control processor receives operator inputs which cause it to assign time slots to different peripheral control elements to configure the system whereby each peripheral control element can be interrogated by addressing it during its time slot. In response to an interrogation, a sensor replies with data corresponding to a sensed parameter while an actuator replies with an acknowledgement and awaits control commands. A unique framing character is generated at the beginning of each time slot for alerting all peripheral elements that the next character generated will be an element address and for synchronizing multiple control processors to an identical time slot clock.

TECHNICAL FIELD [0001] The systems and methods described herein relate to extensible editors and, more particularly, the described implementations relate to highlight rendering services in an extensible editor. BACKGROUND [0002] The process of editing electronic documents generally consists of processing events and key combinations received by an editor. From events and key combinations, an editing space is created. The editing space consists of a document state plus a view state (visual feedback). The view state includes a selection state (what is selected, what is shown as feedback), scroll position, etc. The event interacts with the current state, and an editing model is applied to manipulate feedback or to manipulate the document based on the feedback. [0003] Extensible editors typically provide a set of document manipulation services that can enable macros to perform advanced tasks on the content of a document. With an extensible editor, developers can couple extensions that define or re-define a manner in which the editor responds to events or key combinations and provides visual feedback to a user. For example, if a developer wishes to create a new look to a selection process or a highlighting process in an extensible editor, the developer can create an extension that receives input regarding cursor position, cursor movement, mouse actions, etc. The developer can design the extension to use this input to create visual feedback that differs from a default selection service or highlight service of the editor. However, familiar behavior of the editor (such as clicking a “bold” button) is still retained by the editor. In addition, an extension can also expose virtually any kind of functionality through its own interfaces. [0004] Extensible editors are designed so that one or more extensions can be coupled with the editor. This is accomplished by implementing a set of interfaces to which the extensions must conform. The interfaces are utilized by the extensions to access a host of basic functions so that the extensions themselves are not required to implement such basic functions. The extensions instead utilize the basic functions to perform tasks that supplement or override functions performed by the editor. [0005] Extensible editors are desirable for their ability to include customer extensions to provide a rich editing experience. A significant part of an editing experience involves the highlight rendering model provided by the editor. A user may wish to develop a custom extension that includes a highlight rendering process that provides a unique look and feel to visual feedback that a user sees during an editing session, but that does not actually change the content that is being edited. [0006] When utilizing extensions in an extensible editor, however, a conflict problem can arise if multiple extensions are used simultaneously that act upon the occurrence of the same event or key combination. If a first extension reacts to an event in one way, but a second extension receives tile event after the first extension has acted on it, the second extension may also act on the event and, as a result, override the action of the first extension. This problem can occur even when using only one extension if the extension acts on an event or key combination but does not prevent the (default) editor from subsequently acting on the same event. SUMMARY [0007] An extensible editor for editing electronic documents and/or content is described herein. The extensible editor provides a highlight rendering services component that allows extensions to interface with the editor to provide custom visual feedback to a user during an editing session. Although the visuals are displayed to the user, the actual document content that is being edited is not altered. The editor can thereby implement the custom highlight rendering without having to be aware of details of how the highlight rendering process is implemented in the extension. The extensible editor (“editor”) includes three sets of interfaces for extension integration. [0008] The first set of interfaces is part of a designer extensibility mechanism. The designer extensibility mechanism is used to couple an extension (also called a “designer”) to utilize the event routing model. The designer extensibility mechanism provides the ability to connect an editor extension that can modify editing behavior. An attached designer receives events and key combinations in a predefined order and uses the set of interfaces to create custom editing extensions. [0009] The designer extensibility mechanism includes an edit designer interface that has four methods: translate accelerator, pre-handle event, post-handle event and post-event notify. The methods act as callback routines whenever an event occurs in the editing environment of the editor. When an event comes into the editor, the four methods intercept the event at different points of the editor's event handling process. The editor invokes the methods sequentially. If multiple designers are utilized, the editor invokes the current method on each designer sequentially, in the order in which the designers were registered with the editor. [0010] If a designer acts on an event and wants to prevent any subsequent designer (or the editor) from acting on the event, the designer “consumes” the event by returning an appropriate signal to the editor. The designer returns a different signal when subsequent processing is to continue on an event. [0011] If an event is a key combinations (Ctrl-A, Alt-P, etc.) it first passes through the “translate accelerator” method. This is done in the order that the designers were added to the editor. If a key combination was entered, then the designer acts s upon the event and “consumes” the event so that subsequent designers or the default editor cannot subsequently act upon the event. [0012] The post-editor event notify method is an exception to the rule that consumed events are not passed on to subsequent designers or the editor for further processing. This method is always called on all designers, regardless of whether, or when, an event is consumed. This allows each designer to clean up any internal states that may be anticipating an event that is consumed before is reaching the designer. [0013] The second set of interfaces is included in a selection services component of the editor. The selection services component provides designers with the ability to manage logical selections that are used by commands and other extensions, i.e., the ability to modify the logical selection state of the editor. As a result, all editing commands and services will be able to interact with a custom selection model without having detailed knowledge of the designer that is implementing the selection. [0014] The third set of interfaces is included in a highlight rendering services component. The highlight rendering component allows a user to modify the rendered character attributes of text without modifying the document content. This facility is critical for providing a mechanism for providing user feedback without affecting persistence, undo, etc. BRIEF DESCRIPTION OF THE DRAWINGS [0015] At more complete understanding of exemplary methods and arrangements of the present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings wherein: [0016] FIG. 1 is an exemplary computer system on which the present invention may be implemented. [0017] FIG. 2 is a block diagram of a computer having an extensible editor and several extensions coupled with the editor stored in memory. [0018] FIG. 3 is a block diagram of an editor including a designer interface. [0019] FIG. 4 is a block diagram of an event routing model utilized in an extensible editor. [0020] FIG. 5 is a flow diagram of an event routing model for use in an extensible editor. [0021] FIG. 6 is a block diagram of an editor including a selection services is interface. [0022] FIG. 7 is a block diagram of an editor including a highlighting services interface. DETAILED DESCRIPTION [0023] The invention is illustrated in the drawings as being implemented in a suitable computing environment. Although not required, the invention will be described in the general context of computer-executable instructions, such as program modules, to be executed by a computing device, such as a personal computer or a hand-held computer or electronic device. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that the invention may be practiced with other computer system configurations, including multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. [0000] Exemplary Computer Environment [0024] The various components and functionality described herein are implemented with a number of individual computers. FIG. 1 shows components of typical example of such a computer, referred by to reference numeral 100 . The components shown in FIG. 1 are only examples, and are not intended to suggest any limitation as to the scope of the functionality of the invention; the invention is not necessarily dependent on the features shown in FIG. 1 . [0025] Generally, various different general purpose or special purpose computing system configurations can be used. Examples of well known computing systems, environments, and/or configurations that may be suitable for use with the invention include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. [0026] The functionality of the computers is embodied in many cases by computer-executable instructions, such as program modules, that are executed by the computers. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Tasks might also be performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media. [0027] The instructions and/or program modules are stored at different times in the various computer-readable media that are either part of the computer or that can be is read by the computer. Programs are typically distributed, for example, on floppy disks, CD-ROMs, DVD, or some form of communication media such as a modulated signal. From there, they are installed or loaded into the secondary memory of a computer. At execution, they are loaded at least partially into the computer's primary electronic memory. The invention described herein includes these and other various types of computer-readable media when such media contain instructions programs, and/or modules for implementing the steps described below in conjunction with a microprocessor or other data processors. The invention also includes the computer itself when programmed according to the methods and techniques described below. [0028] For purposes of illustration, programs and other executable program components such as the operating system are illustrated herein as discrete blocks, although it is recognized that such programs and components reside at various times in different storage components of the computer, and are executed by the data processor(s) of the computer. [0029] With reference to FIG. 1 , the components of computer 100 may include, but are not limited to, a processing unit 120 , a system memory 130 , and a system bus 121 that couples various system components including the system memory to the processing unit 120 . The system bus 121 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISAA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus also known as the Mezzanine bus. [0030] Computer 100 typically includes a variety of computer-readable media. Computer-readable media can be any available media that can be accessed by computer 100 and includes both volatile and nonvolatile media, removable and on-removable media. By way of example, and not limitation, computer-readable media may comprise computer storage media and communication media. “Computer storage media” includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 110 . Communication media typically embodies computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more if its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer readable media. [0031] The system memory 130 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 131 and random access memory. (RAM) 132 . A basic input/output system 133 (BIOS), containing the basic routines that help to transfer information between elements within computer 100 , such as during start-up, is typically stored in ROM 131 . RAM 132 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 120 . By way of example, and not limitation, FIG. 1 illustrates operating system 134 , application programs 135 , other program modules 136 , and program data 137 . [0032] The computer 100 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only, FIG. 1 illustrates a hard disk drive 141 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 151 that reads from or writes to a removable, nonvolatile magnetic disk 152 , and an optical disk drive 155 that reads from or writes to a removable, nonvolatile optical disk 156 such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 141 is typically connected to the system bus 121 through an non-removable memory interface such as interface 140 , and magnetic disk drive 151 and optical disk drive 155 are typically connected to the system bus 121 by a removable memory interface such as interface 150 . [0033] The drives and their associated computer storage media discussed above and illustrated in FIG. 1 provide storage of computer-readable instructions, data structures, program modules, and other data for computer 100 . In FIG. 1 , for example, hard disk drive 141 is illustrated as storing operating system 144 , application programs 145 , other program modules 146 , and program data 147 . Note that these components can either be the same as or different from operating system 134 , application programs 135 , other program modules 136 , and program data 137 . Operating system 144 , application programs 145 , other program modules 146 , and program data 147 are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer 100 through input devices such as a keyboard 162 and pointing device 161 , commonly referred to as a mouse, trackball, or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit 120 through a user input interface 160 that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port, or a universal serial bus (USB). A monitor 191 or other type of display device is also connected to the system bus 121 via an interface, such as a video interface 190 . In addition to the monitor, computers may also include other peripheral output devices such as speakers 197 and printer 196 , which may be connected through an output peripheral interface 195 . [0034] The computer may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 180 . The remote computer 180 may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to computer 100 , although only a memory storage device 181 has been illustrated in FIG. 1 . The logical connections depicted in FIG. 1 include a local area network (LAN) 171 and a wide area network (WAN) 173 , but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and the Internet. [0035] When used in a LAN networking environment, the computer 100 is connected to the LAN 171 through a network interface or adapter 170 . When used in a WAN networking environment, the computer 100 typically includes a modem 172 or other means for establishing communications over the WAN 173 , such as the Internet. The modem 172 , which may be internal or external, may be connected to the system bus 121 via the user input interface 160 , or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer 100 , or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation, FIG. 1 illustrates remote application programs 185 as residing on memory device 181 . It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. [0036] FIG. 2 is a block diagram of a computer 200 having a processor 202 and memory 204 . An extensible editor 206 stored in the memory 204 includes an event routing controller 208 , a designer extensibility mechanism 210 , a selection services component 212 , and a highlight rendering services component 214 . Three designers 216 , 218 , 220 are also stored in the memory 204 . Each of the designers 216 - 220 communicates with the editor 206 via the designer extensibility mechanism 210 . Each designer 216 - 220 , as shown, also communicates with the selection services component 212 and the highlight rendering component 214 . It is noted, however, that a designer 216 - 220 may communicate with only the selection services component 212 or the highlight rendering component 214 or with neither. However, as will become clear in the following discussion, each designer 216 - 220 must attach to the editor 206 through the designer extensibility mechanism 210 . [0037] A designer is an editor extension that is used to extend the functionality of the editor 206 and to customize the behavior of the editor 206 . While an “extension” is a generic term for a designer, the term “designer” is utilized in several products of the MICROSOFT CORP., such as INTERNET EXPLORER 5.5, MSHTML (the HIML parsing and rendering engine of INTERNET EXPLORER that displays a document with editable content), the WebBrowser (ActiveX) control, etc. For purposes of the present discussion, terms specific to one or more of such products will be used. For example, in the present discussion, editor extensions will be referred to as designers. A reference to such a specific term (e.g., designer) is meant to include reference to the more generic term (e.g., extension). [0038] The designers 216 - 220 work by intercepting events and commands occurring in, or received by, the editor 206 . When one or more of the designers 216 - 220 intercepts an event (or command), the designer can change how the editor 206 handles the event. Generally, a designer is written to either supplement or override the editor's behavior. Several designers may be attached to the editor 206 at once, thereby dynamically enabling multiple levels of custom functionality. [0039] Designers offer a very powerful tool for customizing the editor 206 . Virtually any part of the editor's behavior can be changed. For example, designers may be used to add spell checking capability to the editor 206 , to add table editing functionality, to add annotation or revision-tracking capability, and so on. It is noted that, although only three designers 216 - 220 are shown in conjunction with the editor 206 , any number of designers may be connected to the editor 206 . [0040] The designer extensibility mechanism 210 , the selection services component 212 , and the highlight rendering services 214 of the editor 206 shown in FIG. 2 provide specific functionality to the editor 206 . Each of the modules and the functionality it provides will be discussed separately, in detail, below. [0041] Designer Extensibility Mechanism [0042] FIG. 3 is a block diagram of an editor 300 similar to the editor 206 shown in FIG. 2 . The editor 300 includes a default event handler 301 , an event routing controller 302 and a designer registry 303 . The editor also includes an edit designer interface 304 that has several methods through which one or more designers (not shown) communicate with the editor 300 . Each designer that is coupled with the editor 300 communicates with the editor 300 through the edit designer interface 304 . Any coupled designer may then communicate with any other interfaces that are a part of the editor 300 . [0043] When a designer is added to the editor 300 , the designer is registered in the designer registry 303 . The event routing controller 302 accesses the designer registry 303 to determine the designers that are coupled into the editor 300 . As will be discussed in greater detail below, the event routing controller 302 utilizes the designer registry 303 when routing events to attached designers. [0044] The methods of the edit designer interface 304 are a translate accelerator method 306 (TranslateAccelerator), a pre-handle event method 308 PreHandleEvent), a post-handle event method 310 (PostHandleEvent), and a post-editor event notify method 312 PostEditorEventNotify). Each method 306 - 312 has two parameters, an event identifier 314 and an event object interface 316 . In one implementation, the event identifier 314 is a value included in HTMLELEMENTEVENTS2 in mshtmdid.h, and the event object interface 316 is IHTMLEventObj, which enables a designer to obtain more extended information about the event. [0045] The methods 306 - 312 act as callback routines whenever an event occurs in the editing environment. In other words, whenever an event occurs that is detected by the editor 300 , each of the methods 306 - 312 is called, in a particular sequence, by the editor 300 to process the event. Processing the event may entail providing an external response to the event, responding internally to the event, not responding to the event, consuming the event and/or passing the event for further processing (i.e., not consuming the event). [0046] The event routing controller 302 determines when a particular method will be called. If multiple designers are registered with the editor 300 in the designer registry 303 , the event routing controller 302 invokes the current method on each designer sequentially, in the order in which the designers were registered with the editor 300 . Further explanation of the event routing technique will be explained below with continuing reference to the elements and reference numerals of FIG. 3 . [0047] FIG. 4 is a block diagram of an event routing model utilized in an extensible editor. In addition to the editor 300 shown in FIG. 3 , FIG. 4 includes a first extension, Designer A 320 , and a second extension, Designer B 330 . Although only two designers 320 , 330 are shown, it should be understood that virtually any number of designers may be added to the editor 300 . The functionality of the routing mechanism when using more than two designers is similar to the description of the routing mechanism using the two designers 320 , 330 . [0048] The editor 300 is designed to receive notification of an event 400 . If the event 400 is a key combination input by a user, then the event routing controller 302 routes the event to the translate accelerator method 306 . The event 400 is made available to a translation accelerator 306 a in Designer A 320 . The translation accelerator 306 a of Designer A 320 may or may not provide a response to the event 400 . If a response is provided to the event 400 by Designer A 320 , then Designer A 320 may consume the event 400 to prevent Designer B 330 from overriding the response to the event 400 by Designer A 320 . To “consume” an event, a designer returns a value (S_OK) to the editor indicating that no further processing should be done on the event. If Designer A 320 does not respond to the event 400 , then the event 400 will be made available to a translation accelerator 306 b of Designer B 330 . To indicate that an event should continue to be processed, a designer returns a different value to the editor (S_FALSE). Designer B 330 may then respond or not respond to the event 400 in the same way as described for Designer A 320 . This process continues with any other designers that may be attached to the editor 300 . [0049] After each designer 320 , 330 has had the opportunity to react to the event 400 (unless one of the designers 320 , 330 has already consumed the event), control of the event 400 is returned to the event routing controller 302 of the editor 300 . It is noted that the editor 300 may include its own translate accelerator that is designed to translate the key combination. This translate accelerator could be a part of the default event handler 301 . In the preferred implementation, the default event handler 301 will receive the key combination (event 400 ) if not already consumed by one of the designers 320 , 330 . The default event handler 301 may or may not be configured to provide a response to the particular key combination. If it is configured to respond to a particular key combination, then an appropriate response is made; if not, then no response will be made to the key combination. [0050] It is significant that if Designer B 330 is configured to act on a particular key combination, Designer B 330 may never receive that key combination if Designer A 320 consumes the combination. Therefore, it is noted that while the implementations described herein significantly improve conflict avoidance in extensible editors, when developing a new designer, careful consideration must be given to the key combinations and events that will trigger actions by a designer. Also, multiple designers can be strategically registered with, the editor 300 to avoid this situation. [0051] If the event 400 is not a key combination, then the event routing controller makes the event 400 available to the designers 320 , 330 via the pre-handle event method 308 . Designer A 320 first has the opportunity to respond to the event 400 . If Designer A 320 is configured to respond to the event 400 , then it provides an appropriate response. After providing a response, Designer A 320 may either consume the event 400 or pass it along. [0052] If, for example, Designer A 320 is an “auto correct” designer and Designer B 330 is a grammar checking designer, an event (entry of a word into the document) would be routed first through the auto correct designer to determine if the word should be corrected. After the word is checked (whether or not it is corrected), the grammar checking designer still requires notice of the event to is perform its function. Therefore, Designer A 320 would act on the event but still make it available to Designer B 330 [0053] If the event 400 is not consumed by Designer A 320 , then the event 400 is made available to Designer B 330 . Designer B 330 has the same options of reacting to the event 400 as described above for Designer A 320 . This is true for each subsequent designer attached to the editor 300 . [0054] After each designer has the opportunity to respond to the event 400 a first time, the event is passed to the default event handler 301 (assuming that the event 400 has not been previously consumed by a designer). The default event handler 301 then provides the default behavior of the editor 300 in response to the event 400 . It is noted that if no designers are attached to the editor 300 , then the editor 300 will simply provide the default editing behavior via the default event handler 301 . [0055] After the default event handler 301 has acted on the event 400 , the designers 320 , 330 are provided another opportunity to respond to the event 400 . The event 400 is made available to the designers 320 , 330 through the post-handle event method 310 . The post-handle event processing is similar to the pre-handle event processing, occurring in the sequence in which the designers 320 , 330 were registered with the editor 300 . [0056] By way of example, suppose that a developer wants to implement an “auto correct” designer that listens to key strokes. The designer, in this case, should receive an event after a typed character is inserted into the document (i.e., PostHandleEvent) rather than before the character is inserted. Receiving the event after the default editor has inserted the character allows the designer to inspect the document with the correct content, allow undo of auto-correct behavior, etc. [0057] After the post-handle event processing is concluded, the event 400 is processed by the default handler 301 . [0058] The post-editor event notify method 312 is called after the editor 300 has finished it post-handling of the event 400 or when a designer 320 , 330 has consumed the event. In the case where the event 400 is consumed by a designer 320 , 330 before a default action takes place and no post-handle event methods are called, a post-editor event notification module 312 a , 312 b is invoked to give the designers 320 , 330 an opportunity to make a final response. For example, suppose a mouse down event starts a selection in a designer that implements basic text selection. If there is a mouse down event, the designer starts the selection. Now, if some other designer consumes the corresponding mouse up event, the designer still needs to know about the mouse up event so it can terminate the selection and stop responding to mouse move events. [0059] FIG. 5 is a flow diagram of the preferred implementation of the event routing model described above for use in an extensible editor 300 . Continuing reference will be made to the elements and reference numerals of FIG. 2 - FIG. 4 in the description of the flow diagram. [0060] At step 500 , an event 400 is received by the editor 300 . The event routing controller 302 determines if the event 400 is a key combination at step 502 . If the event is a key combination (“Yes” branch, step 502 ), then the key combination is translated at step 504 by the designers (if they are configured to translate the particular command) or by the default event handler 301 if no designer translates the key combination and the editor 300 is configured to do so. [0061] If the event is not a key combination (“No” branch, step 502 ) the editor 300 determines if a designer 320 , 330 is attached to the editor 300 at step 508 . If there is not an attached designer (“No” branch, step 508 ), the event is processed by the default event handler 301 at step 510 . If, however, a designer 320 , 330 is attached to the editor 300 (“Yes” branch, step 508 ), then the event 400 is made available to Designer A 320 for pre-handling at step 512 . After Designer A 320 has had the opportunity to act on the event 400 , Designer B 330 (“Yes” branch, step 514 ) has the event 400 made available for processing at step 512 . There is no other designer attached (“No” branch, step 514 ), so the event (if not previously consumed), is passed to the default event handler 301 and processed at step 516 . [0062] After the event 400 is processed by the default event handler 301 of the editor 300 , the event is made available to Designer A 320 for processing at step 518 . Since there is another designer (Designer B 330 ) (“Yes” branch, step 520 ), the event 400 is made available to Designer B 330 for processing at step 518 . When there are no more designers to process the event 400 (“No” branch, step 520 ), the event is processed by the default event handler 301 at step 522 . [0063] It is noted that the above discussion assumes that the event 400 is not consumed by the default event handler 301 or the designers 320 , 330 and is processed by each method of the editor 300 and the designers 320 , 330 . Once an event is consumed, further processing of the event terminates. [0064] After the event has been through the pre-handle event method 308 and the post-handle event method 310 , the post-editor event notification method 312 is called (step 524 ). Unless consumed by the default event handler 310 or one of the designers 320 , 330 , each designer 320 , 330 is notified of any response to the event 400 from any other module as previously described. [0065] Designer Extensibility Mechanism Interfaces [0066] In addition to the edit designer interface 304 described above, the designer extensibility mechanism 210 includes an edit services interface. In MSHTML, the edit services interface is designated as IHTMLEditServices, used to add or remove edit designers and control the current selection. Although the general descriptions of the designer extensibility mechanism can be applied and implemented in any extensible editor and extensions therefor, for discussion purposes, the described implementation will refer to MICROSOFT MSHTML terminology to describe interfaces exposed by a designer extensibility mechanism to allow extensions to be couple to properly communicate with an extensible editor. Those skilled in the art will appreciate the functions enabled by the described interfaces to implement custom extensions for the extensible editor. [0067] The following are detailed descriptions of the edit designer interface and the edit services interface. [0068] Edit Designer Interface (IHTMLEditDesigner) [0069] The edit designer interface includes the following methods: [0070] TranslateAccelerator [0071] Description: Called by MSHTML to translate a key combination entered by a user into an appropriate command. Syntax:   HRESULT TranslateAccelerator (     DISPID inEvtDispId,     IHTMLEventObj *pIEventObj Parameters:   inEvtDispId     [in] DISPID that specifies the event.   pIEventObj     [in] Pointer to an IHTMLEventObj interface that specifies the     event. Return Values:   Returns S_OK to indicate that the event has been completely   handled and that no further processing should take place, either by   other edit designers or the MSHTML Editor. Returns S_FALSE to   indicate that other edit designers and the MSHTML Editor should   perform their processing this event. [0072] PreHandleEvent [0073] Description: Called by MSHTML before the MSHTML Editor processes an event, so that the designer can provide its own event handling behavior. Syntax:   HRESULT PreHandleEvent (     DISPID inEvtDispId,     IHTMLEventObj *pIEventObj Parameters:   inEvtDispId     [in] DISPID that specifies the event.   pIEventObj [in] Pointer to an IHTMLEventObj interface that specifies the event. Return Values:   Returns S_OK to indicate that the event has been completely   handled and that no further processing should take place, either by   other edit designers or the MSHTML Editor. Returns S_FALSE to   indicate that other edit designers and the MSHTML Editor should   perform their pre-event processing. [0074] PostHandleEvent [0075] Description: Called by MSHTML after the MSHTML Editor processes an event, so that the designer can provide its own event handling behavior. Syntax:   HRESULT PostHandleEvent (     DISPID inEvtDispId,     IHTMLEventObj *pIEventObj Parameters:   inEvtDispId     [in] DISPID that specifies the event.   pIEventObj     [in] Pointer to an IHTMLEventObj interface that specifies the     event. Return Values:   Returns S_OK to indicate that the event has been   compoetley handled and that no further processing should take   place, either by other edit designers or the MSHTML Editor.   Returns S_FALSE to indicate that other edit   designers and the MSHTML Editor should perform their   post-event processing. [0076] PostEditorEventNotify [0077] Description: Called by MSHTML after an event has been handled by the MSHTML Editor and any registered edit designers. Syntax:   HRESULT PostHandleEvent (     DISPID inEvtDispId,     IHTMLEventObj *pIEventObj Parameters:   inEvtDispId     [in] DISPID that specifies the event.   pIEventObj     [in] Pointer to an IHTMLEventObj interface that specifies the     event. Return Values:   Returns S_OK if successful, or an error value otherwise. [0078] Edit Services Interface (IHTMLEditServices) [0079] The edit designer interface includes the following methods: [0080] AddDesigner [0081] Description: Registers an IHTMLEditDesigner interface to receive event notification from the editor.   Syntax:     HRESULT AddDesigner (       IHTMLEditDesigner *pIDesigner     ) ;   Parameters:     *pIDesigner       [in] Pointer to an IHTMLEditDesigner interface to register for event notification.   Return Values:     Returns S_OK if successful, or an error value otherwise. [0082] GetSelectionServices [0083] Description: Registers an IHTMLEditDesigner interface to receive event notification from the editor. Syntax:   HRESULT GetSelectionServices (     IMarkupContainer *pIContainer     ISelectionServices **ppSelSvc   ) ; Parameters:   *pIContainer     [in] Pointer to an IMarkupContainer interface for which an     ISelectionServices interface is desired.   **ppSelSvc     [out] Address of a pointer to a variable that receives an     ISelectionServices interface pointer for the ISelectionServices     interface on the editor's selection object. Return Values:   Returns S_OK if successful, or an error value otherwise. [0084] MoveToSelectionAnchor [0085] Description: Moves a markup pointer to the location of an anchor for the current selection.   Syntax:     HRESULT MoveSelectionToAnchor (       IMarkupPointer *pIStartAnchorr     ) ;   Parameters:     *pIStartAnchor       [in] Pointer to an IMarkupPointer interface to move the location of an anchor for the selection.   Return Values:     Returns S_OK if successful, or an error value otherwise. [0086] MoveToSelectionEnd [0087] Description: Moves markup pointer to the end of the current selection. Syntax:   HRESULT MoveToSelectionEnd (     IMarkupPointer *pIEndAnchor   ) ; Parameters:   *pIEndAnchor     [in] Pointer to an IMarkupPointer interface to move to the end     of the current session. Return Values:   Returns S_OK if successful, or an error value otherwise. [0088] RemoveDesigner [0089] Description: Unregisters a designer from the editor. Syntax:   HRESULT RemoveDesigner (     IHTMLEditDesigner *pIDesigner   ) ; Parameters:   pIDesigner     [in] Pointer to the IHTMLEditDesigner interface to remove     from the event notification queue. Return Values:   Returns S_OK if successful, or an error value otherwise. [0090] Selection Services [0091] Selection services provides extensions a way to modify a selection process of an extensible editor to which the designers are coupled. Although the general descriptions of the selection services can be applied and implemented in any extensible editor and extensions therefor, for discussion purposes, the described implementation will refer to MICROSOFT MSHTML terminology to describe interfaces exposed by a selection services component to allow extensions to properly communicate with an extensible editor to utilize the selection services component. Those skilled in the art will appreciate the functions enabled by the described interfaces to implement custom extensions for the extensible editor. [0092] FIG. 6 is a block diagram of an extensible editor 600 that includes a designer interface 602 , an event routing mechanism 604 , and a selection services component 606 . The selection services component 606 includes several interfaces: a selection services interface 608 (ISelectionServices), a selection services listener interface 610 (ISelectionServiceListener), an element segment interface 612 (IElementSegment), a segment list interface 614 (ISegmentList), and a segment interface 616 (ISegment). These interfaces 608 - 616 will be discussed in greater detail, below. [0093] The role of the selection services interfaces 608 - 616 is to provide designers or other editing extensions with the ability to modify the logical selection state. Consequently, all editing commands and services can interact with a custom selection model without having detailed knowledge of the designer that is implementing the selection. [0094] For example, the “bold” command is able to implement the operation of making something bold without having any knowledge of the specifics of a given designer. The command is only aware of what part of the document is selected, and it is configured to make the selected region of the document bold. [0095] Selection Service Interface (ISelectionServices) [0096] The selection services interface 608 provides methods to programmatically clear, add and remove segments from a selection object. The methods include an add element segment method 618 (AddElementSegment), a get markup container method 620 (GetMarkupContainer), a get selection services listener method 622 (GetSelectionServicesListener), an add segment method 624 (AddSegment), a remove segment method 626 (RemoveSegment), and a set selection type method 628 (SetSelectionType). The following are detailed description of the available selection services interface 608 methods. [0097] AddElementSegment [0098] Description: The add element segment method 618 creates an IElementSegment interface for an element in a markup container and adds the segment to the editable selection. Syntax:   HRESULT AddElementSegment (     IHTMLElement *pIElement,     IElementSegment **ppISegmentAdded   ) ; Parameters:   *pIElement     [in] Pointer to an IHTMLElement interface that specifies the     element to add to the selection.   **ppISegmentAdded     [out] Address of a pointer to a variable that receives an     IElementSegment interface pointer for the element segment     added to the selection environment. Return Values:   Returns S_OK if successful, or an error value otherwise. [0099] GetMarkupContainer [0100] Description: The get markup container method 620 retrieves the markup container for the current editable selection. Syntax:   HRESULT GetMarkupContainer (     IMarkupContainer **ppIContainer   ) ; Parameters:   **ppIContainer     [out] Address of a pointer to a variable that receives an     IMarkupContainer interface pointer to the interface for the     markup container that contains the current editable selection. Return Values:   Returns S_OK if successful, or an error value otherwise. [0101] GetSelectionServicesListener [0102] Description: The get selection services listener 622 method retrieves an ISelectionServicesListener interface for the current editable selection so that the editor can process certain selection events. Syntax:   HRESULT GetSelectionServicesListener (     ISelectionServicesListener **ppISelectionServicesListener   ) ; Parameters:   **ppISelectionServicesListener     [out] Address of a pointer to a variable that receives an     ISelectionServicesListener interface pointer to the interface     that the editor will use with the current editable selection. Return Values:   Returns S_OK if successful, or an error value otherwise. [0103] AddSegment [0104] Description: The add segment method 624 creates an ISegment interface for the content between two markup pointers in a markup container, and adds the segment to the editable selection. Syntax:   HRETURN AddSegment (     IMarkupPointer *pIStart,     IMarkupPointer *pIEnd,     ISegment **ppISegmentAdded   ) ; Parameters:   *pIStart     [in] Pointer to an IMarkupPointer interface that specifies the     start point for adding the segment.   *pIEnd     [in] Pointer to an IMarkupPointer interface that specifies the     end point for adding the segment.   **ppISegmentAdded     [out] Address of a pointer to a variable that receives an     ISegment interface pointer to the interface for the added     segment in the selection environment. Return Values:   Returns S_OK if successful, or an error value otherwise. [0105] RemoveSegment [0106] Description: The remove segment method 626 (RemoveSegment) removes a segment from the editable selection. Syntax:   HRESULT RemoveSegment (     ISegment *pISegment   ) ; Parameters:   *pISegment     [in] Pointer to an ISegment interface that specifies the     segment to remove. Return Values:   Returns S_OK if successful, or an error value otherwise. [0107] SetSelectionType [0108] Description: The set selection type method 628 (SetSelectionType) sets the selection type and clears any existing selection. Syntax:   HRESULT SetSelectionType;     SELECTION_TYPE eType     ISelectionServicesListener *pIListener   ) ; Parameters:   eType     [in] SELECTION_TYPE enumeration that specifies the type     of selection to set.   *pIListener     [in] Optional. Pointer to an ISelectionServiceListener     interface specifying the interface to associate with this     selection. Set to NULL if unused. NOTE: Although this     parameter is optional, without this parameter, the editor will     not be able to restore the selection. Return Values:   Returns S_OK if successful, or an error value otherwise. [0109] Element Segment Interface (IElementSegment) [0110] The element segment interface 610 provides methods that control a fragment of HTML markup in the current editable selections that consists of a single element. The element segment interface 612 includes a get element method 630 (GetElement), an ‘is primary’ method 632 (IsPrimary), and a set primary method 634 (SetPrimary). To obtain an IElementSegment interface for a fragment of HTML markup representing an element, the ISelectionServices::AddElementSegment method is used. [0111] The selection object uses element segments to mark fragments of HTML markup that are whole elements, in particular control elements. [0112] GetElement [0113] Description: The get element method 612 (GetElement) retrieves the element to which this segment refers. Syntax:   HRESULT GetElement (     IHTMLElement **ppIElement   ) ; Parameters:   **ppIElement     [out] Address of a pointer to a variable that receives an     IHTMLElement interface pointer for the interface     representing the element to which the segment refers. Return Values:   Returns S_OK if successful, or an error value otherwise. [0114] Is Primary [0115] Description: The is primary method 632 (IsPrimary) determines whether the control element represented by this segment is the primary element of a multi-element selection. The primary element of a multiple selection is typically the first one chosen by a user when a selection was made. The primary element typically has distinctive handles that indicate it is the primary element. For example, the primary element might have white handles while the other elements have black ones). Syntax:   HRESULT IsPrimary (     BOOL *pfPrimary   ) ; Parameters:   *pfPrimary     [out] Pointer to a BOOL that receives TRUE if the element is     the primary element, or FALSE otherwise. Return Values:   Returns S_OK if successful, or an error value otherwise. [0116] Set Primary [0117] Description: The set primary method (SetPrimary) sets or unsets a control element as a primary element in a control selection. The primary element of a multiple selection is typically the first one chosen by a user when a selection was made. The primary element typically has distinctive handles that indicate it is the primary element. For example, the primary element might have white handles while the other elements have black ones). Syntax:   HRESULT SetPrimary     BOOL fPrimary   ) ; Parameters:   fPrimary     [in] BOOL that specifies TRUE to set the element as the     primary element, or FALSE to unset it as primary. Return Values:   Returns S_OK if successful, or an error value otherwise. [0118] Segment Interface (ISegment) [0119] The segment interface 616 provides a method that creates containers (segments) for fragments of HTML markup in the current editable selection. These segments can include both a range of elements and element fragments. The segment interface 616 includes a get pointers method 636 (GetPointers). [0120] GetPoiners [0121] Description: The get pointers method 636 (GetPointers) positions markup pointers at the start and end of the selection segment. Syntax:   HRESULT GetPointers (     IMarkupPointer *pIStart,     IMarkupPointer *pIEnd   ) ; Parameters:   pIStart     [in] Pointer to an IMarkupPointer interface that specifies the     markup pointer to position at the beginning of the segment.   pIEnd     [in] Pointer to an IMarkupPointer interface that specifies the     markup pointer to position at the end of the segment. Return Values: Returns S_OK if successful, or an error value otherwise. [0122] Segment List Interface(ISegmentList) [0123] The segment list interface 614 provides methods that access information about a list of the segments in the current selection. The segment list interface 614 includes a create iterator method 638 (CreateIterator), a get type method 640 (GetType), and an ‘is empty’ method 640 (IsEmpty). [0124] CreateIterator [0125] Description: The create iterator method 638 creates an ISegmentListIterator interface used for traversing the members of a segment list. Syntax:   HRESULT CreateIterator (     ISegmentListIterator **ppIIter   ) ; Parameters:   ppIIter     [out] Address of a pointer to a variable that receives an     ISegmentListIterator interface pointer for the newly created     ISegmentListIterator. Return Values:   Returns S_OK if successful, or an error value otherwise. [0126] GetType [0127] Description: The get type method 640 retrieves the type of the selection. Syntax:    HRESULT GetType (       SELECTION_TYPE *peType    ); Parameters:    peType       [out] Pointer to a variable of type SELECTION_TYPE that       receives the selection type value. Return Values:    Returns S_OK if successful, or an error value otherwise. [0128] IsEmpty [0129] Description: The ‘is empty’ method 642 determines whether the segment list is empty. Syntax:   HRESULT IsEmpty (     BOOL *pfEmpty   ) ; Parameters:   pfEmpty     [out] Pointer to a variable of type BOOL that receives TRUE     if the segment list is empty, or FALSE if it is not empty. Return Values:   Returns S_OK if successful, or an error value otherwise. [0130] Selection Services Listener Interface (ISelectionServicesListener) [0131] The selection services listener interface 610 provides methods that the editing component of MSHTML calls whenever certain events fire for a selection object that has a registered ISelectionServicesListener interface. This interface provides processing for undo events, for selection type changes, and whenever the mouse pointer exits the scope of an element in the editable selection. An application should supply an implementation of this interface for a selection object so that the editing component of MSHTML can respond to these events. The selection services listener interface 610 includes a begin selection undo method (BeginSelectionUndo) 644 , an end selection undo method 646 (EndSelectionUndo), a get type detail method 648 (GetTypeDetail), an ‘on change type’ method 650 (OnChangeType), and an ‘on selected element exit’ method 652 (OnSelectedElementExit). To register an ISelectionServicesListener interface for a particular selection object, the ISelectionServices::SetSelectionType method or ISelectionServices::OnChangeType method is used. [0132] BeginSelectionUndo [0133] Description: The begin selection undo method 644 is called by the editor 600 when an editing operation is beginning that may result in a change in selection after the editing operation. This method exists so that the designers may place their own units on an Undo queue so that a selection may be restored to its original state when the editing process was started. Syntax:    HRESULT BeginSelectionUndo (VOID); Parameters:    None. Return Values:    Returns S_OK if successful, or an error value otherwise. [0134] EndSelectionUndo [0135] Description: The end selection undo method 644 is called by the editor 600 at the end of an editing operation that may result in a change in selection after the editing operation. This method exists so that the designers may place their own units on an Undo Queue so that a selection may be restored to its original state when the editing process was started. Syntax:    HRESULT EndSelectionUndo (VOID); Parameters:    None. Return Values:    Returns S_OK if successful, or an error value otherwise. [0136] GetTypeDetail [0137] Description: The get type detail method 648 is called by MSHTML to obtain the name of the selection type. This method allows a host application to provide the name of a selection type when implementing a custom selection mechanism. MSHTML will return a value of ‘undefined’ if the host does not implement this method. Syntax:    HRESULT GetTypeDetail (       BSTR *pTypeDetail    ) ; Parameters:    pTypeDetail       [out] BSTR that specifies the name of the selection type. Return Values:    Returns S_OK if successful, or an error value otherwise. [0138] OnChangeType [0139] Description: The ‘on change type’ method 650 is called by the editor 600 when the type of a selection changes. This method is used to implement custom processing that should take place when a selection is initiated or when a selection changes type. Syntax: HRESULT OnChangeType (   SELECTION_TYPE eType,     ISelectionServicesListerner *pIListener   ) ; Parameters:   eType     [in] SELECTION_TYPE enumeration that specified the new     selection type.   pIListener     [in] Optional. Pointer to an ISelectionServicesListener     interface to register with the new selection. Can be set to     NULL. Return Values:    Returns S_OK if successful, or an error value otherwise. [0140] OnSelectedElementExit [0141] Description: The ‘on selected element’ exit method 652 is called by the editor 600 whenever an element that intersects selection undo is removed from the document. This method exists so that the selection can be updated by the extensible editor (either removed or adjusted). Syntax:   HRESULT OnSelectedElementExit (     IMarkupPointer *pIElementStart,     IMarkupPointer *pIElementEnd,     IMarkupPointer *pIElementContentStart,     IMarkupPointer *pIElementContentEnd   ) ; Parameters:   *pIElementStart     [in] Pointer to an IMarkupPointer interface specifying the     point just before the element's opening tag.   *pIElementEnd     [in] Pointer to an IMarkupPointer interface specifying the     point just after the element's closing tag.   *pIElementContentStart     [in] Pointer to an IMarkupPointer interface specifying the     point just after the element's opening tag.   *pIElementContentEnd     [in] Pointer to an IMarkupPointer interface specifying the     point just before the element's closing tag. Return Values:   Returns S_OK if successful, or an error value otherwise. [0142] Highlight Rendering Services [0143] Highlight rendering services allows a user to modify the rendered character attributes of text without modifying the document content. This facility is critical for providing a mechanism for providing user feedback without modifying the document content. This component is critical for providing a mechanism for providing user feedback without affecting persistence, undo, etc. [0144] FIG. 7 is a block diagram of an extensible editor 700 that includes a designer interface 702 , an event routing mechanism 704 , and a highlight rendering services component 706 . The highlight rendering services component 706 includes two interfaces: a highlight services interface 708 (IHighlightRenderingServices), and a highlight segment interface 710 (IHighlightSegment). These interfaces 708 , 710 will be discussed in greater detail, below. [0145] Highlight Rendering Services Interface (IHighlightRenderingServices) [0146] The highlight rendering services interface 708 provides methods that enable a designer to control which sections of a document are highlighted on the screen and the style of highlighting. The methods include an add segment method 712 (AddSegment), a move segment to pointers method 714 (MoveSegmentToPointers), and a remove segment method 716 (RemoveSegment). The following are detailed description of the available selection services interface 608 methods. [0147] AddSegment [0148] Description: The add segment method 712 creates a highlight segment for the markup between two display pointers and highlights it according to a specified rendering style. Syntax:   HRESULT AddSegment (     IDisplayPointer *pDispPointerStart,     IDisplayPointer *pDispPointerEnd,     IHTMLRenderStyle *pIRenderStyle,     IHighlightSegment **ppISegment   ) ; Parameters:   pDispPointerStart     [in] Pointer to an IDisplayPointer interface representing the     start point of the segment to be highlighted.   pDispPointerEnd     [in] Pointer to an IDisplayPointer interface representing the     end point of the segment to be highlighted.   pIRenderStyle     [in] Pointer to an IHTMLRenderStyle interface representing     the style with which to render the specified segment.   ppISegment     [out] Address of a pointer to a variable that receives an     IHighlightSegment interface pointer for the interface that     represents the highlight segment between pDispPointerStart     and pDispPointerEnd. Return Values:   Returns S_OK if successful, or an error value otherwise. [0149] MoveSegmentToPointers [0150] Description: The move segments to pointers method 714 redefines a highlight segment and its style. Syntax:   HRESULT MoveSegmentToPointers (     IHighlightSegment *pISegment,     IDisplayPointer *pDispPointerStart,     IDisplayPointer *pDispPointerEnd   ) ; Parameters:   pISegment     [in] Pointer to an IHighlightSegment interface to redefine.   pIDispPointerStart     p[in] Pointer to an IDisplayPointer interface for the new start     point of the highlight segment.   pIDispPointerEnd     [in] Pointer to an IDisplayPointer interface for a new endpoint     of the highlight segment. Return Values:    Returns S_OK if successful, or an error value otherwise. [0151] RemoveSegment [0152] Description: The remove segment method 716 removes a highlight segment from a collection of segments that are highlighted. Syntax:    HRESULT RemoveSegment (       IHighlightSegment *pISegment    ) ; Parameters:    pISegment       [in] Pointer to an IHighlightSegment interface to remove. Return Values:    Returns S_OK if successful, or an error value otherwise. [0153] Highlight Segment Interface (IHighlightSegment) [0154] The highlight segment interface 710 enables a user to control a highlighed section of a document. This interface does not provide any methods of its own beyond those available from it parent interface, ISegment. [0155] Description: The highlight segment interface 710 provides type checking for the segments added or moved from the highlighted sections through the IHighlightRenderingServices interface. [0156] Remarks: This interface does not provide any methods of its own beyond those available from its parent interface, ISegment. [0157] Conclusion [0158] The services described above provide an applications program interface (API) for an extensible editor (MSHTML). The interfaces and the methods associated with each interface are summarized as follows: [0159] IHTMLEditServices AddDesigner GetSelectionServices MoveToSelectionAnchor MoveToSelectionEnd RemoveDesigner [0165] IHTMLEditDesigner TranslateAccelerator PreHandleEvent PostHandleEvent PostEditorEventNotify [0170] ISelectionServices AddElementSegment GetMarkupContainer GetSelectionServicesListener AddSegment RemoveSegment SetSelectionType [0177] ISelectionServicesListener BeginSelectionUndo EndSelectionUndo GetTypeDetail OnChangeType OnSelectedElementExit [0183] ISegmentList CreateIterator GetType IsEmpty [0187] ISegment [0188] IElementSegment GetElement IsPrimary SetPrimary [0192] IHighlightRenderingServices AddSegment MoveSegmentToPointers RemoveSegment [0196] IHighlightSegment [0197] The interfaces can be utilized by an extension coupled with the extensible editor to add new features to the editor, to augment existing features, or to override the editor's default behavior. Extensions can be used to modify the editor to provide customized feedback and to present a rich editing experience to a user. [0198] Although details of specific implementations and embodiments are described above, such details are intended to satisfy statutory disclosure obligations rather than to limit the scope of the following claims. Thus, the invention as defined by the claims is not limited to the specific features described above. Rather, the invention is claimed in any of its forms or modifications that fall within the proper scope of the appended claims, appropriately interpreted in accordance with the doctrine of equivalents.

An extensible editor allows integration of extensions that modify the editor's default behavior and provide customized feedback to users. The editor includes interfaces through which extensions are connected to the editor and through which selection services and highlight rendering services are provided. The selection services interfaces provide a clear separation of a logical selection position in the document and the visual feedback provided for the selection, allowing extensions to be designed that provide customized selection feedback. The highlight rendering services interfaces provide an extension with the ability to augment an existing selection without modifying the actual document. The editor also includes an event routing model that works to decrease the occurrence of conflicts between the editor and extensions and between extensions. Upon the occurrence of an event, the editor routes the event to each extension before the editor's default handling of the event occurs. When an extension responds to an event, the extension may “consume” the event by indicating to the editor not to allow further processing of the event. After an event has been pre-processed by each extension, the default editor acts on the event. The editor then routes the event to each extension again, to allow each extension to process the event after the default editor has acted. When the post-processing is completed, each extension is notified of the actions taken by the editor and by each of the other extensions.

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of U.S. patent application Ser. No. 10/196,684 filed Jul. 15, 2002 now abandoned and claims benefit of priority from U.S. Provisional Patent Application Ser. No. 60/305,130 filed Jul. 13, 2001. FIELD OF THE INVENTION The present invention relates to the field of automatic door closing devices, and in particular devices that hold a door open to allow people to pass through. BACKGROUND OF THE INVENTION Door closing devices are well known, and have existed for centuries. A simple string, pulley and counterweigh is sufficient to close a door after opening. Modern designs incorporate hydraulic or pneumatic devices to moderate the closure rate. Modern designs also include fully automatic door controls, which are expensive, and typically require continuous availability of power. These systems are almost universally electrically powered, and employ line power with limited or lacking facilities for closely coupled backup. A typical door closing device provides sufficient closure force to overcome a strong wind, friction, or to push small objects. Due to the damper in the door, a typical symmetric damping function, and a requirement to arm the device while opening the door, opening a door having an automatic door closing device involves application of a significant force. Perhaps more importantly, if a stream of people seek to pass through the door, it is necessary, or polite, for the first person through to hold the door for later people. This often results in significant delays and bottlenecks, since the person holding the door open often must stand in the door passage, applying a force, or stand in a contorted position to avoid being in the doorway.); Hydraulic and pneumatic door closures for controlling closing characteristics of swing doors are well known and have been widely used. See, for example, U.S. Pat. Nos. 4,793,023, 4,414,703 and 4,378,612. Primarily hydraulically, pneumatically operated openers, or opening assist mechanisms are also known. U.S. Pat. Nos. 3,948,000, 3,936,977, 4,955,194 and 4,429,490 teach such mechanisms. Additionally, a variety of electromechanical automatic door operators are known. See, for example, U.S. Pat. Nos. 2,910,290, 3,127,160, 4,045,914 and 4,220,051. Each type of door opener, hydraulic, pneumatic and electromechanical, has its own advantages and disadvantages. It has also been known to combine these mechanisms in order to obtain some of the advantages of each. See, for example, U.S. Pat. Nos. 3,874,117, 3,129,936, 1,684,704, 2,256,613, and 4,438,835. See also, U.S. Pat. No. 5,956,249, expressly incorporated herein by reference. Thus, there is a need for an improved device for closing doors which is power efficient and avoids the requirement for manual override for a second person passing though the door. See, for example, U.S. Pat. Nos. 6,138,412; 6,002,217; 5,992,444; 4,580,365; 5,488,896; expressly incorporated herein by reference. See also, patents now in US Class 16/62, each patent therein being expressly incorporated herein by reference, including but not limited to U.S. Pat. No. 6,154,924 (Door closer unit); U.S. Pat. No. 6,151,753 (Door closer to generate a sudden change in the transmission ratio during the closing phase); U.S. Pat. No. 6,047,440 (Non-rotating pinion cap); U.S. Pat. No. 5,943,736 (Door closer); U.S. Pat. No. 5,802,670 (Door closer); U.S. Pat. No. 5,553,353 (Door damping system); U.S. Pat. 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No. 4,937,914 (Door control device); U.S. Pat. No. 4,793,023 (Door closer and holder); U.S. Pat. No. 4,763,385 (Door closure transmission utilizing an eccentric pinion); U.S. Pat. No. 4,744,125 (Door closer transmission including an eccentric pinion); U.S. Pat. No. 4,686,739 (Door closer); U.S. Pat. No. 4,665,583 (Door closer piston assembly having separate head portions); U.S. Pat. No. 4,653,229 (Holding installation for double doors); U.S. Pat. No. 4,502,180 (Door control device having piston assembly with separately formed rack); U.S. Pat. No. 4,455,708 (Door closer having a braking mechanism comprising an elastomeric bag); U.S. Pat. No. 4,419,786 (Door closer assembly); U.S. Pat. No. 4,414,703 (Door closer and holder); U.S. Pat. No. 4,394,787 (Hydraulic door closer construction); U.S. Pat. No. 4,387,482 (Modular single or double action door closure system); U.S. Pat. No. 4,378,612 (Door closer delayed action speed control system); U.S. Pat. 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No. 1,121,084 (16/62); U.S. Pat. No. 1,117,693 (16/62); U.S. Pat. No. 1,097,605 (16/62 16/51); U.S. Pat. No. 1,097,604 (16/62 16/49 16/71); U.S. Pat. No. 1,025,309 (16/62 16/278 292/2); U.S. Pat. No. 1,019,857 (16/62 16/51); U.S. Pat. No. 1,017,714 (16/62); U.S. Pat. No. 1,003,653 (16/62); U.S. Pat. No. 1,003,651 (16/62); U.S. Pat. No. 998,732 (16/62 251/310); U.S. Pat. No. 970,445 (16/62); U.S. Pat. No. 962,143 (16/62); U.S. Pat. No. 960,641 (16/62); U.S. Pat. No. 884,789 (16/62); U.S. Pat. No. 868,357 (16/62 16/49 188/130 188/304); U.S. Pat. No. 859,737 (60/573 16/62 60/594 74/99R); U.S. Pat. No. 732,369 (16/62); U.S. Pat. No. 727,051 (16/62 251/229); U.S. Pat. No. 724,325 (16/62); U.S. Pat. No. 722,369 (406/165 16/62); U.S. Pat. No. 696,116 (16/62 16/49); U.S. Pat. No. 679,905 (16/62); U.S. Pat. No. 672,237 (16/62); U.S. Pat. No. 669,158 (16/62); U.S. Pat. No. 655,107 (16/62); U.S. Pat. No. 633,682 (16/62); U.S. Pat. No. 633,015 (16/62); U.S. Pat. No. 632,697 (16/62); U.S. Pat. No. 629,001 (16/62); U.S. Pat. No. 627,828 (16/62 16/32 16/DIG39 267/34 267/218 267/223); U.S. Pat. No. 627,717 (16/62); U.S. Pat. No. 602,688 (16/62); U.S. Pat. No. 602,687 (16/62); U.S. Pat. No. 577,917 (16/62). See, further, U.S. patents listed below, expressly incorporated herein by reference: U.S. Pat. No. 6,259,352 (Door lock system); U.S. Pat. No. 6,250,014 (Compact door coordinator); U.S. Pat. No. 6,240,598 (Arrangement for controlling an angularly movable member); U.S. Pat. No. 6,237,647 (Automatic refueling station); U.S. Pat. No. 6,227,508 (Adjustable support apparatus); U.S. Pat. No. 6,223,469 (Pivot-hung door drive); U.S. Pat. No. 6,209,431 (Automated degate and trim machine); U.S. Pat. No. 6,199,322 (Method and apparatus for automatically driving an open/close body); U.S. Pat. No. 6,167,589 (Control mechanism including a permanent magnet system); U.S. Pat. No. 6,112,368 (Temperature compensating valve); U.S. Pat. No. 6,079,162 (Partition forming a draft-free fire barrier; and a draft-free fire barrier; and, further, methods of their operation); U.S. Pat. No. 6,065,184 (Apparatus for automatic closing of sliding doors); U.S. Pat. No. 6,061,964 (Portable remote controlled door closer); U.S. Pat. No. 6,050,117 (Motor vehicle door lock or the like); U.S. Pat. No. 6,049,444 (Rotatable door and door opening mechanism for a cartridge); U.S. Pat. No. 6,049,287 (Door with integrated smoke detector and hold open); U.S. Pat. No. 6,032,331 (Checking mechanisms with variable plane trigger plates); U.S. Pat. No. 5,992,444 (Control device for door closer); U.S. Pat. No. 5,956,249 (Method for electromechanical control of the operational parameters of a door in conjunction with a mechanical door control mechanism); U.S. Pat. No. 5,953,789 (Checking mechanism for reciprocative devices); U.S. Pat. No. 5,944,367 (Door closing apparatus); U.S. Pat. No. 5,927,766 (Latching mechanism for a motor control center); U.S. Pat. No. 5,913,763 (Method for controlling the operational modes of a door in conjunction with a mechanical door control mechanism); U.S. Pat. No. 5,910,075 (Portable remote-controlled door closer); U.S. Pat. No. 5,901,992 (Electromechanical locking mechanism for door leaves having a door closing device); U.S. Pat. No. 5,899,169 (Automatic hay, grain and pellet feeder for livestock); U.S. Pat. No. 5,878,530 (Remotely controllable automatic door operator permitting active and passive door operation); U.S. Pat. No. 5,862,630 (Door closer); U.S. Pat. No. 5,850,671 (Door closer); U.S. Pat. No. 5,829,098 (Reinforcement basal attachment plate for reciprocating operative device); U.S. Pat. No. 5,829,097 (Hold open control for a door closer); U.S. Pat. No. 5,813,739 (Flammable material storage cabinet); U.S. Pat. No. 5,813,282 (Powered sliding-door system and actuating devices for the same); U.S. Pat. No. 5,806,246 (Powered sliding-door system and actuating devices for the same); U.S. Pat. No. 5,804,931 (Wall partition system and a device and method for the operation of a wall partition system); U.S. Pat. No. 5,789,887 (Automatic door); U.S. Pat. No. 5,771,635 (Pneumatic device and system); U.S. Pat. No. 5,732,508 (Gate closer); U.S. Pat. No. 5,727,348 (Portable remote controlled door closer); U.S. Pat. No. 5,727,286 (Door closer with a pneumatic dashpot); U.S. Pat. No. 5,709,009 (Door closer for the non-fire side of a fire-door safety installation); U.S. Pat. No. 5,706,765 (Method and apparatus for cooping chickens); U.S. Pat. No. 5,706,551 (Door closers and dampers primarily for door closers); U.S. Pat. No. 5,687,507 (Apparatus for selective alteration of operating parameters of a door); U.S. Pat. No. 5,687,451 (Revolving door device); U.S. Pat. No. 5,681,140 (Multiple compartment body for waste materials); U.S. Pat. No. 5,666,692 (Adjustable power closure); U.S. Pat. No. 5,657,511 (Piston-type door closer with adjustable closing speeds); U.S. Pat. No. 5,651,536 (Combined door closer/hinge with variable rotary friction damping performance); U.S. Pat. No. 5,651,216 (Door closer for a two-panel door with a closing sequence control mechanism); U.S. Pat. No. 5,638,639 (Emergency door with retractable nose piece, interiorly mounted operating hardware, and hinge supports); U.S. Pat. No. 5,592,902 (Method and apparatus for cooping chickens); U.S. Pat. No. 5,592,780 (Door position controlling apparatus); U.S. Pat. No. 5,579,607 (Convenient automatic closing system for doors); U.S. Pat. No. 5,572,768 (Door closer); U.S. Pat. No. 5,553,521 (Door spring adjusting tool); U.S. Pat. No. 5,542,216 (Sliding door closing device); U.S. Pat. No. 5,525,963 (Apparatus for actuating a safety device); U.S. Pat. No. 5,517,719 (Adjustable delayed-action door closer); U.S. Pat. No. 5,515,649 (Automatic door operator); U.S. Pat. No. 5,513,469 (Retractable sliding door); U.S. Pat. No. 5,513,467 (Linear drive power door operator); U.S. Pat. No. 5,511,284 (Door hold open device); U.S. Pat. No. 5,510,686 (Automated garage door closer); U.S. Pat. No. 5,507,120 (Track driven power door operator); U.S. Pat. No. 5,497,533 (Surface mounted door closer housing resistant to vandalism); U.S. Pat. No. 5,488,896 (Self aligning piston rod); U.S. Pat. No. 5,487,206 (Door control device); U.S. Pat. No. 5,477,589 (Piston-type door closer with adjustable closing speeds); U.S. Pat. No. 5,471,708 (Pneumatic door closer); U.S. Pat. No. 5,437,079 (Door hinge); U.S. Pat. No. 5,417,013 (Overhead door closer with slide rail for concealed installation in door panels or door frames); U.S. Pat. No. 5,414,894 (Door closer); U.S. Pat. No. 5,392,562 (Universal mounting plate for door opener); U.S. Pat. No. 5,386,885 (Electro-mechanical pivot wing drive for pivoting wings of doors or the like); U.S. Pat. No. 5,386,614 (Door closer); U.S. Pat. No. 5,382,016 (Sheet sorter with a stapler having a controlled sheet aligning member); U.S. Pat. No. 5,375,861 (No-hands baby stroller); U.S. Pat. No. 5,309,676 (Balanced door closing apparatus); U.S. Pat. No. 5,291,630 (Damper and method of controlling a door); U.S. Pat. No. 5,254,040 (Handball—squash court conversion system); U.S. Pat. No. 5,253,782 (Article dispensing apparatus); U.S. Pat. No. 5,251,400 (Control for a door closer having a power-assist opening feature); U.S. Pat. No. 5,246,258 (Rim type door lock with interchangeable bolt assemblies and adjustable backset plate assemblies); U.S. Pat. No. 5,239,778 (Modular door control apparatus with quick release connection); U.S. Pat. No. 5,224,677 (Pull down display and storage apparatus); U.S. Pat. No. 5,216,418 (Emergency service rescue marker); U.S. Pat. No. 5,192,398 (Coke box with indirectly cooled receiving chamber and exhaust gas burner); U.S. Pat. No. 5,191,678 (Wind resistant door hardware); U.S. Pat. No. 5,190,617 (Coke handling apparatus including coke box and carrier vehicle); U.S. Pat. No. 5,138,795 (Power sliding door closer); U.S. Pat. No. 5,135,083 (Input responsive damper); U.S. Pat. No. 5,090,089 (Automatic door closing device); U.S. Pat. No. 5,083,342 (Door closure delay device); U.S. Pat. No. 5,048,151 (Mechanical door check); U.S. Pat. No. 5,046,283 (Power sliding door closer); U.S. Pat. No. 5,033,234 (Door coordinator); U.S. Pat. No. 5,027,553 (Garage door closing apparatus); U.S. Pat. No. 5,027,473 (Refrigerator door closer); U.S. Pat. No. 5,020,189 (Door closure mechanism); U.S. Pat. No. 5,012,608 (Spray boom); U.S. Pat. No. 5,005,881 (Door locking mechanism); U.S. Pat. No. 5,002,331 (Pedal actuated vehicle door closer); U.S. Pat. No. 4,997,527 (Coke handling and dry quenching method); U.S. Pat. No. 4,995,194 (Power-assist door closer); U.S. Pat. No. 4,973,894 (Method and arrangement for optimizing of the function of a door closer); U.S. Pat. No. 4,958,144 (Water-flow detector); U.S. Pat. No. 4,944,066 (Adjustable closer arm); U.S. Pat. No. 4,937,913 (Door closer); U.S. Pat. No. 4,935,989 (Pneumatic door closer with sustained closing force during closure); U.S. Pat. No. 4,916,267 (Door closer position monitor); U.S. Pat. No. 4,884,369 (Sliding door closer); U.S. Pat. No. 4,878,265 (Hold-open mechanism for use with a door closer); U.S. Pat. No. 4,876,764 (Closer having door position indicator); U.S. Pat. No. 4,844,567 (Vending machine with controlled return access door); U.S. Pat. No. 4,835,905 (Door position indicator for a door closer); U.S. Pat. No. 4,821,521 (Positioning drive for a motor vehicle door closing device); U.S. Pat. No. 4,803,754 (Electromechanical door holder-closer); U.S. Pat. No. 4,791,414 (Water-flow detector); U.S. Pat. No. 4,788,742 (Torque modification apparatus for use with a door closer); U.S. Pat. No. 4,783,882 (Door closer assembly); U.S. Pat. No. 4,782,333 (Water-flow detector with rapid switching); U.S. Pat. No. 4,763,111 (Door closer having sound generating function); U.S. Pat. No. 4,754,522 (Door holders for selectively positioning doors against closure); U.S. Pat. No. 4,750,236 (Track-type door hold-open device); U.S. Pat. No. 4,722,116 (Remote setting-control mechanism for a door-closer latch); U.S. Pat. No. 4,721,946 (Door control device with alarm switch); U.S. Pat. No. 4,709,445 (Method and apparatus for closing a door); U.S. Pat. No. 4,707,882 (Pneumatic damper); U.S. Pat. No. 4,669,147 (Door closer); U.S. Pat. No. 4,665,584 (Buoyant valve member closing device for doors); U.S. Pat. No. 4,663,887 (Apparatus for controlling the closing sequence of double doors); U.S. Pat. No. 4,663,800 (Holding device for door closers); U.S. Pat. No. 4,660,250 (Door closer); U.S. Pat. No. 4,649,598 (Energy saver sliding door closer including a valved weight); U.S. Pat. No. 4,648,151 (Jamb plate for door closer); U.S. Pat. No. 4,593,584 (Power tongs with improved hydraulic drive); U.S. Pat. No. 4,583,324 (Apparatus for controlling the closing sequence of double leaved doors); U.S. Pat. No. 4,575,880 (Auto-flush system); U.S. Pat. No. 4,573,238 (Door closer incorporating self-cleaning and temperature compensating flow control valve); U.S. Pat. No. 4,561,343 (Sequencing valve mechanism); U.S. Pat. No. 4,534,278 (Livestock confinement building wall-vent controller); U.S. Pat. No. 4,513,953 (Gas spring with extension force controlled as a function of temperature); U.S. Pat. No. 4,506,407 (Releasable hold-open device for a door closer); U.S. Pat. No. 4,501,090 (Automatic door operator for swing doors); U.S. Pat. No. 4,498,112 (Tape cartridge receptacle); U.S. Pat. No. 4,486,917 (Door closer with a compressible braking sleeve); U.S. Pat. No. 4,485,522 (Door-closing hinge having a spring and pin mechanism); U.S. Pat. No. 4,483,044 (Pneumatic door closer having resilient braking sleeve and cooperating piston rod incremental braking enlargements); U.S. Pat. No. 4,419,787 (Door closer assist linkage); U.S. Pat. No. 4,401,346 (Apparatus for controlling the operation of a door); U.S. Pat. No. 4,386,446 (Door closer); U.S. Pat. No. 4,375,735 (Air lock door control apparatus); U.S. Pat. No. 4,371,201 (Reversing ratchet door closer); U.S. Pat. No. 4,365,442 (Automatic door control system); U.S. Pat. No. 4,358,870 (Hydraulic hinge with door closing mechanism); U.S. Pat. No. 4,349,939 (Automatic door closer); U.S. Pat. No. 4,348,835 (Automatic door opening device); U.S. Pat. No. 4,317,254 (Door closer); U.S. Pat. No. 4,298,140 (Newspaper and magazine vending machine); U.S. Pat. No. 4,290,161 (Automated carwash brush assembly); U.S. Pat. No. 4,289,995 (Electric door operator with slip clutch and dynamic braking); U.S. Pat. No. 4,287,639 (Door closer permitting free-swing and regular-closer modes); U.S. Pat. No. 4,286,411 (Manual balanced door with door closer arm); U.S. Pat. No. 4,285,094 (Door closing apparatus); U.S. Pat. No. 4,267,619 (Controlled release door holder); U.S. Pat. No. 4,254,308 (Vandal resistant public telephone); U.S. Pat. No. 4,237,578 (Releasable retaining means and fire door control system); U.S. Pat. No. 4,232,798 (Automatic vending machine for delivering containers having edible product therein); U.S. Pat. No. 4,185,356 (Door closer); U.S. Pat. No. 4,179,092 (Mounting device for door closer); U.S. Pat. No. 4,161,804 (Heat-actuated door latch); U.S. Pat. No. 4,161,183 (Vibration sensitive valve operating apparatus); U.S. Pat. No. 4,155,199 (Lockable gate mechanism with automatic reindexing feature); U.S. Pat. No. 4,155,144 (Damper device); U.S. Pat. No. 4,151,380 (Post mounted public telephone); U.S. Pat. No. 4,148,111 (Temperature compensating hydraulic door closer); U.S. Pat. No. 4,146,405 (Unitary dishwasher); U.S. Pat. No. 4,139,182 (Spring device); U.S. Pat. No. 4,130,913 (Door closer); U.S. Pat. No. 4,121,319 (Releasable retaining means); U.S. Pat. No. 4,112,127 (Method for processing and filling a dough product); U.S. Pat. No. 4,103,392 (Door closing apparatus); U.S. Pat. No. 4,102,006 (Door closer); U.S. Pat. No. 4,102,005 (Door closer arm); U.S. Pat. No. 4,083,080 (Door closer); U.S. Pat. No. 4,079,479 (Sliding door closure and locking mechanism); U.S. Pat. No. 4,075,734 (Door closer); U.S. Pat. No. 4,069,546 (Soffit plate and limit stop for use with hydraulic door closer); U.S. Pat. No. 4,069,544 (Electrically actuated door holder and release); U.S. Pat. No. 4,067,084 (Automatic door closer); U.S. Pat. No. 4,064,589 (Door closer); U.S. Pat. No. 4,050,114 (Door closer assembly); U.S. Pat. No. 4,048,694 (Hydraulic door closer with adjustable time delay dampener); U.S. Pat. No. 4,040,144 (Door assister); U.S. Pat. No. 4,034,437 (Pressure-free fail-safe emergency door closer); U.S. Pat. No. 4,016,381 (Switch arrangement for door closers); U.S. Pat. No. 3,989,286 (Device for arresting a door); U.S. Pat. No. 3,966,289 (Electric power coupler); U.S. Pat. No. 3,935,614 (Electromechanical door holder-closer); U.S. Pat. No. 3,934,306 (Door closure device). See also the following patents relating to door closers, which are expressly incorporated herein by reference: IN175305 (A Spring Actuated Door Closer); EP1219770 (Swing Door With Sliding Arm Door Closer); US2002070564 (Door Closer); US2002066228 (Movable Partition With A Plurality Of Laterally Movable Wall Elements); US2002066157 (Door Closer); U.S. Pat. No. 6,397,431 (Spring Assembly Normally Inactive That Opts For Causing Towards Any Position With Reciprocative Door Closer Devices); U.S. Pat. No. 6,397,430 (Adjustable Hydraulic Backcheck Door Closer); US2002063430 (Door Lock Drive Unit); TW459890Y (Improved Structure Of Door Closer); TW459889Y (Improved Structure Of Door Closer); TW430014Y (Sliding Seat For Hydraulic Press Door Closer); TW430013Y (Oiling Control Device For Hydraulic Press Door Closer); IE890371L (DOOR CLOSER); IE800525L (DOOR CLOSER); NZ503115 (Door Closer); NZ502364 (Arrangement For Controlling An Angularly Movable Member); NZ502403 (Device For Controlling An Angularly Movable Member, Such As Overhead Door Closers And Floor Springs); U.S. Pat. No. 6,375,018 (Jewelry Support Rack); U.S. Pat. No. 6,374,505 (Installation Template For A Door Closer; PL346265 (DOOR CLOSER); JP2002038805 (CRIME PREVENTION DEVICE TO FIX DOOR CLOSER); JP2002038791 (DOOR CLOSER APPARATUS FOR VEHICLE); CN2483483U (Closer For Door); U.S. Pat. No. 6,354,343 (Automatic Fueling System And Components Therefor); CA2321871 (DOOR CLOSER); CA2320809 (DOOR CLOSER); CA2311054 (BALANCED DOOR CLOSING APPARATUS); CA2305994 (DOOR CLOSER); JP2002061453 (STOP-ANGLE ADJUSTING MECHANISM FOR DOOR CLOSER); CA2305214 (DOOR CLOSER); AU743753 (Door Closer); JP2002013343 (JOINT DEVICE FOR LINK MECHANISM FOR DOOR CLOSER); TW450308Y (Door Closer); U.S. Pat. No. 6,345,412 (Arrangement For Controlling An Angularly Movable Member); AU3918401 (Door Hinge With Integrated Door Closer); US2002007564 (Installation Template For A Door Closer); US2002007563 (INSTALLATION TEMPLATE FOR A DOOR CLOSER); ZA200000390 (Door Closer.); DE10031786 (Door Closer With Slide Rail And Shaft Comprises Basic And Positively Connected Reinforcing Modules Whose Shafts Protrude From Housing From); DE10030332 (Track For Fixing To Door Frames Or Door Leaves Comprises A Slider, Guide Surfaces Running At An Angle To The Vertical Central Plane Of The); DE10030325 (Slider For Door Frames/Leaves Is Arranged In A Guide Rail So That Moves In The Longitudinal Direction And Is Connected To A Tilting Arm Of); WO0198615 (CONFIGURATION FOR OPENING AND CLOSING A DOOR OR A GATE); US2001054260 (Patio Screen Door Closer); US2001052728 (Motor Vehicle Door Locking System Arrangement); CN2467721U (Closer And Opener With Friction Brake For Sliding Door); JP2001323720 (DOOR CLOSER); JP2001329743 (DOOR CLOSER); CN2463523U (Pneumatic Spring Door Closer); GB2362923 (Installation Template For A Door Closer); EP1159503 (DOOR CLOSER); U.S. Pat. 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No. 6,296,230 (Door Lifting Device); PL342839 (DOOR CLOSER); EP1141508 (DOOR CLOSER MOUNTING BRACKET WITH SCREW HOLDERS); CN2451673U (Hinge Hidden Buffer Door Closer With Braking Device); JP2001234663 (STOPPER FOR DOOR CLOSER); JP2001214661 (JOINT DEVICE BETWEEN ARMS IN DOOR CLOSER); JP2001207723 (HINGED DOOR PROVIDED WITH DOOR CLOSER); JP2001200675 (STOP DEVICE FOR DOOR CLOSER); JP2001193345 (AUTOMATIC DOOR CLOSER); EP1134350 (Blocking Device For A Door Provided With A Door Closer); EP1134349 (Overhead Door Closer With Improved Means Of Rotation); U.S. Pat. No. 6,282,750 (Power Adjustment Size Indicator For A Door Closer); US2001013762 (Automated Garage Door Closer); SK4452000 (DOOR CLOSER); JP2001173306 (DOOR AUTOMATIC CLOSER; TW428658Y (Improvement On Door Closer); HU0101011 (DOOR CLOSER); EP 1126119 (Door Closing Arrangement For Double Doors); EP1126118 (Door Closing Arrangement For Double Doors); EP1126117 (Adjustable Power Closure); WO0155541 (DRIVE ROD FITTING); U.S. Pat. No. 6,266,847 (Door Operator And Process For Operation Of A Door Operator); EP1120523 (Turning Device For Sectional Overhead Door); JP2001065233 (DOOR CLOSER); US2001007163 (Damper Assembly That Opts To Open Doors For Usage With Reciprocating Door Closer Devices); HU0100767 (DOOR CLOSER); CN2438809U (Closer For Sliding Door); U.S. Pat. No. 6,260,236 (Door Closer With Hydraulic Back Checking); KR202611Y (LOCKING DEVICE OF A HINGE SHAFT FOR A DOOR CLOSER); GB2358222 (Power Adjustment Size Indicator For A Door Closer); KR202010Y (PISTON OF DOOR CLOSER); KR202006Y (CLOSE CONTROL OF DOOR CLOSER); KR198717Y (DOOR CLOSER); TW417716Y (Modified Hydraulic Door Closer); TW416465Y (Improved Positioning Structure Of Hydraulic Door Closer; KR265254 (DOOR CLOSER); GB897848 (Improvements In Or Relating To A Door Closer); GB754913 (Concealed Door Closer); CN2435488U (Door Closer With Folding Arm); CN1299433T (Hinge Type Automatic Door Closer); WO0142604 (SLIDING PANEL COMPRISING SEVERAL WALL ELEMENTS THAT CAN BE DISPLACED LATERALLY); U.S. Pat. No. 6,240,598 (Arrangement For Controlling An Angularly Movable Member); HU0003821 (DOOR CLOSER); CN2431369U (Automatic Door Closer); U.S. Pat. No. 6,234,520 (Method And Apparatus For Disabling An Airbag System In A Vehicle); KR190952Y (A AUTO STOPPER FOR DOOR CLOSER); KR190951Y (A AUTO STOPPER FIXED DEVICE FOR DOOR CLOSER); KR190950Y (A AUTO STOPPER FOR DOOR CLOSER); KR190914Y (DOOR CLOSER LEVER); CN1293733T (Door Closer); EP1101893 (Blocking Device For Door Closer, Electromagnet And Slider); DE10015769 (Door-Closer Comprises Three Self-Contained Stages Arranged So That Open-Hold-Close Functions Are Performable Through Interaction Of Elements . . . ); EP1096094 (Jack Apparatus For The Opening/Closing Of A Door Wing); DE19951610 (Closure Sequence Control For Two-Paneled Door Involves Door Having Stand Panel And Passage Panel Automatically Closed By Door Closer, Stop); GB750067 (Production And Treatment Of Filamentary Materials; GB217146 (Improved Door Closer And Check); GB413459 (Improvements In Or Relating To Door Closer); GB324872 (Door Closer); GB268623 (Adjustable Door-Closer For Motor-Car Doors); U.S. Pat. No. 6,205,615 (Door Closer); GB581425 (An Improved Automatic Door Closer And Check Device); GB542467 (Improvement In And Relating To Door Closer); GB495687 (Door Closer); DE19946516; WO0123202 (VEHICLE DOOR); U.S. Pat. No. 6,199,222 (Portable Combined Toilet And Waste Holding Tank); GB918777 (Door Closer); GB914660 (Automatic Door Closer); GB908001 (Automatic Door Closer); GB903664 (Door Closer Assembly); U.S. Pat. No. 6,185,868 (Automatic Closer Of Pop-Up Door Of Vehicle); U.S. Pat. No. 6,167,589 (Control Mechanism Including A Permanent Magnet System); GB937926 (Hydraulically Operated Door Closer); GB936320 (Concealed Overhead Door Closer); GB839419 (Door Closer With Expansion Chamber); GB775719 (Door Closer); GB774241 (Door Closer); U.S. Pat. No. 6,179,187 (Ergonomically Enhanced Backpack); U.S. Pat. No. 6,178,698 (Balanced Door Closing Apparatus); GB978966 (Hydraulically Retarded Door Closer); GB978693 (Automatic Door Closer In Combination With Mechanism For Connecting It To A Door); GB879278 (Door Closer); FR2798693 (Automobile Door Lock For Increasing Travel Of Rod Comprises Lock Striker And Return Striker Articulated On Pivots Connected To Lock, Lock R); JP2001049946 (DOOR CLOSER HAVING STOPPER); JP2001049924 (DOOR CLOSER DEVICE); JP2001049923 (DOOR CLOSER DEVICE); GB991149 (A Process And Apparatus For Steel Manufacture); GB982139 (Improvements In Or Relating To A Door Closer); DE19940728 (Profiled Pin For Door Closer Has Plastics Pin Set In Longitudinal Slit Of End Part Of Closer To Be Axially Pretensioned By Screw With Tip); JP2001032618 (DOOR CLOSER TYPE HYDRAULIC HINGE); GB1014354 (Means For Connecting A Door To A Door Closer); GB1000864 (Door Closer); EP1081317 (Door Lock Device With Automatic Door Closing Mechanism); DE10032418 (Cylindrical Door Closer Has Damper And Gas Compression Spring In Cylinder With Sealing Packets For Time Constants); GB1120102 (Door-Closer); GB1114973 (Spring Operated Door Closer With A Hydraulic Check Device); GB1103966 (Automatic Door Closer); GB1103857 (Door Closer); GB1039690 (Door Closer); JP2001012138 (DOOR CLOSER); KR261344 (DOOR CLOSER BODY AND MANUFACTURING METHOD THEREOF); KR187638Y (DOOR CLOSER OF SHIELD ROOM); KR187613Y (DOOR CLOSER OF A HINGE TYPE); KR187428Y (FIREPROOF DOOR CLOSER); KR187352Y (DOOR CLOSER BODY INSERT MOLDED ALUMINUM PIPE); GB1142819 (Hydraulic Door-Closer); TW392032 (Hinge Type Automatic Door Closer); EP1076141 (Door Lock Device For Motor Vehicles); DE19938282 (Fire Safety Door Has Automatic Door Closer With Release Element Activated In Response To Fire For Operation Of Door Closure Element); JP2001003621 (DRIVING CONTROLLER FOR DOOR CLOSER DEVICE); EP1073821 (HINGE TYPE AUTOMATIC DOOR CLOSER); WO0105612 (IMPROVEMENTS TO TELESCOPIC GUIDES USED FOR FIXING NESTABLE DOORS OF RAILWAY WAGONS); IE911745 (Door Closer); IE911447 (Door Closer); DE19953570 (Hydraulic Door Closer Joint Has Axle Fitting Through Lower Rotary Cylinder, Fixing Cylinder And Upper Rotary Cylinder And Has Guide Element); U.S. Pat. No. 6,164,685 (Deployment Door For Air Bag Module); GB2351766 (Cavity Closer/Window Or Door Frame Fixing Clip); EP1066443 (DEVICE IN CONNECTION WITH MOUNTING OF A DOOR CLOSER); EP1064446 (DOOR CLOSER); EP1062401 (DOOR CLOSER); U.S. Pat. No. 6,154,924 (Door Closer Unit); DE10018725 (Closing Sequence Control Device For Two-Leaf Door With Door Closer Transmits Modulated And Encoded Signals Between Resting Leaf And Outer); JP2000291326 (DOOR CLOSER FOR OPENED DOOR); U.S. Pat. No. 6,151,753 (Door Closer To Generate A Sudden Change In The Transmission Ratio During The Closing Phase); KR179181Y (JIG FOR BODY OF DOOR CLOSER); CN1273620T (Door Closer); AU2313300 (Installation Template For A Door Closer); SG73357 (Floor-Mounted Door Closer Device); GR3033849T (AUTOMATIC DOOR CLOSER AND PROCESS FOR MOUNTING THE SAME); U.S. Pat. No. 6,145,942 (Hold-Open Door Closure Assembly And Method For Using Same); KR173511Y (SPEED CONTROL VALVE FOR FLOW PATH OF DOOR CLOSER); JP2000240349 (DOOR CLOSER); JP2000240350 (SLIDING DOOR CLOSER); U.S. Pat. No. 6,138,412 (Door Opener And Closer); EP1051558 (BLOCKING DEVICE FOR A DOOR PRIVIDED WITH A DOOR CLOSER); AU2106400 (Door Closer); AU1792300 (Door Closer Mounting Bracket With Screw Holders); U.S. Pat. No. 6,131,967 (Door Lock Assembly For Automotive Vehicles); KR172493Y (DOOR-CLOSER); GB2349173 (Door Closer); WO0061903 (VERTICAL TYPE DOOR CLOSER); U.S. Pat. No. 6,125,505 (Door Closer And Mounting Bracket); KR165486Y (VERTICAL TYPE DOOR CLOSER); EP1042576 (DOOR CLOSER); CN2397236U (Improved Closer For Door); CN1266938 (Lamp Tube Type Noiseless Door Closer); WO0052291 (DOOR CLOSERS); DE19857295 (Automatic Door Closer Has Spring Loaded Sliding Piston Provided With Compression Fitted Minimum Play Linear Sliding Bearing); JP2000204841 (DOOR CLOSER); FR2790275 (Door Closer Has Lock Assembly Masked By Strip With Pivot Rib And Pull Handle); WO0047854 (INSTALLATION TEMPLATE FOR A DOOR CLOSER); EP1030140 (Tray. Of Adjustable Capacity For Refrigerator Doors); CN87207062U (AUTOMATIC DOOR CLOSER); U.S. Pat. No. 6,092,334 (Door Locking Device For A Door Closer Having A Fire Actuated Mechanism For Unlocking The Door Locking Device); CN85200341U (AN AUTOMATIC DOOR CLOSER); JP2000192726 (DOOR CLOSER); JP2000186460 (DOOR CLOSER); CN1219214 (DOOR CLOSER UNIT); WO0042283 (DOOR CLOSER); WO0042282 (DRIVE); WO0042281 (DOOR CLOSER MOUNTING BRACKET WITH SCREW HOLDERS); WO0037755 (ARRANGEMENT AT A DOOR LOCKING SYSTEM FOR A MOTOR VEHICLE); WO0036255 (DOOR CLOSER); WO0032897 (DOUBLE-WING DOOR, ESPECIALLY A FIRE PROTECTION DOOR); WO0011297 (DOOR CLOSER); WO0008285 (DOOR CLOSER); CN2377322U (Two-Position Door Closer); JP2000160925 (SAG REMOVING DEVICE FOR WIRE IN CLOSER OF SLIDING DOOR); DE19932291 (Car Door Lock Of Pre-Alerted Swivel Catches Has Catch Axes Eccentric To Their Bearer Axes Using Counterpart Locking Component Opposing End); DE19922916 (Door Closer With Drive For Closing Door Casement Has Spring Piston And Damping Piston Mounted Rotationally Secured Relative To Stroke Cam); DE19901769 (Sequential Door Closer For Double Doors Has Control Device For Controlling Blocking Device Of Overlapping Door Panel Only On Each N-Th One); DE19901517 (Door Closer For Automatically Closing Doors Has Hollow Compensating Body Mounted In Pressure Compensating Chamber Of Piston Cylinder Unit); JP2000130005 (DOOR CLOSER); JP2000104431 (DRIVE CONTROL DEVICE FOR DOOR CLOSER DEVICE); KR205613 (AUTOMATIC STOPPER DEVICE AND DOOR CLOSER FOR FIRE PREVENTION); DE19857297 (Door Closer.); RU2133861 (THRUST REVERSER FOR TURBOJET ENGINE WITH DOORS CONNECTED TO FRONT PANEL FORMING INTAKE); KR149513Y (A SIDE CLOSER FOR EMERGENCY DOOR OF FIRE-PROOF SHUTTER); KR149512Y (A SIDE CLOSER FOR EMERGENCY DOOR OF FIRE-PROOF SHUTTER); KR8603003Y (DOOR CLOSER); KR199991 (DOOR CLOSER); DE19855425 (Swing Fire Doors Have Door Closers With Sliding Blocks At The Closer Arms On A Horizontal Guide At The Door Frame And A Lock For The . . . ); CN1248660 (Multi-Purpose Door Closer Installed Behind Door); U.S. Pat. No. 6,061,964 (Portable Remote Controlled Door Closer); AU5623899 (Door Closer); AU4139599 (Door Closer); DE19856285 (Building Break E.G. Window Or Door Closer Hinge Has Axis In Tubular Sleeve Containing Coaxial Hinge Roller Axis Plus Hinge Axis End Cover); DE19855402 (Twin Leaf Fire Door For Building Has Flap, Servo And Locking Strips Mounted Under Common Cover); U.S. Pat. No. 6,049,444 (Rotatable Door And Door Opening Mechanism For A Cartridge); U.S. Pat. No. 6,047,440 (Non-Rotating Pinion Cap); GB2343713 (Door Closer: Mounting Bracket); GB2343712 (Door Closer: Mounting); GB2343711 (Door Closer: External Cover For Pinion Shaft); CN2363031U (Door Bottom Gap Automatic Closer); CN2363011U (Wind-Proof Door Closer); AU1679488 (DOOR CLOSER); EP0993535 (DEVICE FOR TRANSMITTING MECHANICAL CONTROL MOVEMENTS AND/OR ELECTRIC SIGNALS BETWEEN A DOOR ACTUATING DEVICE AND A DOOR CLOSER DEVICE OF A); DE19848071 (Locating Structure Of Oil Pressure Door Closer Is Composed Of A Locating Plate, A Main Body And A Number Of Fastening Pins); AU3443599 (Hinge Type Automatic Door Closer); CN2361797U (Full-Automatic Door Closer For Fire-Proof Door); JP2000054723 (METHOD AND DEVICE FOR REDUCING OPENING OF DOOR CLOSER); JP2000045624 (DOOR CLOSER); CN2357089U (Improved Positioning Structure For Oil Hydraulic Door Closer); U.S. Pat. No. 6,032,330 (Locating Structure Of Oil Pressure Door Closer); U.S. Pat. No. 6,029,403 (Method For The Sealed Mounting Of A Window-Lifter Mechanism In A Vehicle Door And Door For The Application Of This Method); DE19901234 (Door Closer For Building Has Adjustable Spacing Between Drive Shaft And Follower Roller); DE19842568 (Drive Mechanism For Door Closer Preferably Consists Of Piston Cylinder Unit In Housing, Energy Accumulator, And Driven Shaft); JP2000017944 (ADJUSTMENT MECHANISM FOR STOPPING ANGLE OF DOOR CLOSER); JP2000017943 (ADJUSTMENT MECHANISM FOR STOPPING ANGLE OF DOOR CLOSER); JP2000008696 (STOP ANGLE ADJUSTING MECHANISM FOR DOOR CLOSER); U.S. Pat. No. 6,024,137 (Automatic Fueling System And Components Therefor); KR166651 (DOOR CLOSER); ZA9002428 (SLIDING DOOR CLOSER); DE19834889 (Door Closer Has Structured Body Surfaces In A Lightweight Casting To Give A Compact And Visually Attractive Unit); US6011468 (Garage Door Alarm); CN2343292U (Door Closer); CN2342081U (Hinge Type Closer For Door Bottom Seam); AU3350399 (Device In Connection With Mounting Of A Door Closer); AU713769 (A Motorised Door Opener And Closer And A Shuttle Therefor); JP11336424 (SLIDING DOOR CLOSER); JP11324474 (DOOR CLOSER); JP11336416 (CLOSER FOR AUTOMATIC CLOSING USED ESPECIALLY IN VEHICLE DOOR); CN1230624 (Hydraulic Damping Door Closer); U.S. Pat. No. 6,003,568 (Automatic Fueling System And Components Therefor); KR9304980Y (PISTON ASSEMBLY IN DOOR CLOSER); KR9304468Y (DOOR CLOSER); KR9301037Y (ARM IN DOOR CLOSER); KR9301036Y (ATTACHMENT DEVICE IN DOOR CLOSER); KR9301035Y (DOOR CLOSER); KR9203850Y (DOOR CLOSER); KR9108391Y (DOOR CLOSER); KR9107346Y (DOOR CLOSER); KR9104710Y (DOOR CLOSER); KR9101528Y (DOOR CLOSER (KR9010938Y (DOOR CLOSER); KR9009664Y (DOOR CLOSER); KR9009663Y (DOOR CLOSER); KR9000691Y (SPRING PRESS CONTROL DEVICE FOR DOOR CLOSER); KR8800141Y (BRAKING DEVICE OF DOOR-CLOSER); KR8703627Y (O-SHAPE RING OF DOOR CLOSER FOR PREVENTING OF A OIL FLOW); EP0972902 (Door Closer With Reduced Dimensions); DE19831783 (Door Closer With Automatic Closing Action For Swing Doors Has Two Force-Transferring Rods Mounted In Swivel Bearing On One Side And . . . ); JP11324484 (CLOSER FOR TOP-RAILED SLIDING DOOR); JP11315662 (CLOSER FOR SLIDING DOOR); JP11324487 (LINEAR MOTOR TYPE DOOR CLOSER); JP11324450 (DOOR CLOSER DEVICE FOR VEHICLE); JP11324489 (AUTOMATIC DOOR CLOSER); JP11324482 (DOOR CLOSER); KR9301633 (POWERED SLIDING DOOR OPENER/CLOSER FOR VEHICLES); KR9301488 (DOOR CLOSER); KR9301487 (DOOR CLOSER); KR8503284Y (DOOR CLOSER); KR8200088U (DOOR CLOSER); KR8001195U (DOOR CLOSER); KR8000602U (DOOR CLOSER OF A SIGNAL APPARATUS BOX FOR RAILROAD); U.S. Pat. No. 5,992,444 (Control Device For Door Closer); DE19828034 (Door Or Window Blind Frame Closure Plate With Receiver Groove); JP11303495 (DOOR CLOSER); JP11303501 (DOOR CLOSER STOPPING ANGLE-ADJUSTING MECHANISM); JP11311055 (SILENCING MECHANISM FOR SLIDING DOOR CLOSER DEVICE); JP11303483 (DOOR CLOSER DEVICE FOR CAR); WO9961739 (WINDOW AND DOOR CLOSING MECHANISM); WO9961729 (VEHICLE DOOR LATCH); AU3246999 (Blocking Device For A Door Provided With A Door Closer); JP11270220 (DOOR CLOSER); U.S. Pat. No. 5,971,514 (Cabinet Door Prop Unit); GB2337290 (Door Closer Ensuring Firm Door Abutment: Walk-In Baths); EP0956415 (DOOR CLOSER FOR GENERATING A SPEED-INCREASING LEAP DURING THE CLOSURE PHASE); CN1219214T (Door Closer Unit); WO9954583 (HINGE TYPE AUTOMATIC DOOR CLOSER); KR8500947 (DOOR CLOSER); U.S. Pat. No. 5,956,806 (Apparatus For Automatically Closing A Swing Door); IL56851 (DOOR CLOSER WITH ASSIST OR DOOR OPERATING FEATURES); IL23508 (HYDRAULIC DOOR CLOSER); WO9949166 (DEVICE IN CONNECTION WITH MOUNTING OF A DOOR CLOSER); U.S. Pat. No. 5,951,069 (Door Closing Apparatus); U.S. Pat. No. 5,946,858 (Collapsible Window Lift Module With Diagonal Structural Link); U.S. Pat. No. 5,943,736 (Door Closer); NZ194288 (DOOR CLOSER); SG27183G (DOOR CLOSER); JP11166355 (SLIDING DOOR CLOSER DEVICE); JP11141202 (VEHICLE DOOR CLOSER DEVICE); JP11141226 (JOINT DEVICE BETWEEN ARMS IN DOOR CLOSER); JP11190165 (DOOR CLOSER AND DOOR CLOSER INSTALLING TOOL AND METHOD); JP11159238 (DOOR LOCKING DEVICE FOR DOOR CLOSER); JP11125059 (DOOR CLOSER); EP0941947 (Bulk Material Container With Hinged Opening Door Pivotable About An Axis); NZ222866 (CHECKABLE POWER ACTUABLE STAY FOR A SWINGING DOOR WITH A DOOR CLOSER); JP11093501 (DOOR CLOSER); JP11104058 (STOPPER/LATERAL SLIP PREVENTIVE DOOR CLOSER/SLIP PREVENTION WITH SHOE WIPER/SHOE SCRATCHER/SHOE MAT AND ITS MANUFACTURE); WO9942687 (ELECTRICALLY CONTROLLED LOCK FOR A SAFE); NZ205385 (PNEUMATICALLY DAMPED SWING DOOR CLOSER: STOP MECHANISM TO HOLD DOOR IN FIXED POSITION); WO9939069 (BLOCKING DEVICE FOR A DOOR PROVIDED WITH A DOOR CLOSER); CN2318360U (Closer Or Opener For Door); DE19901773 (Blocking Device For A Door Provided With A Door Closer); DE19803790 (Fixing Device For Door Provided With Door Closer); NZ329672 (SLIDING DOOR WITH WHEEL AXIALLY ADJUSTABLE AND WHEEL FIXED TO DOOR VIA BRACKET AND MEMBER SLIDABLE RELATIVE TO BRACKET IN PLANE TRANSVERSE T); EP0931895 (Device For Temporarily Closing An Opening Element On A Fixed Part Of A Motor Vehicle Body); U.S. Pat. No. 5,910,075 (Portable Remote-Controlled Door Closer); U.S. Pat. No. 5,901,412 (Top-Mounted Door Closer); EP0922151 (DOOR CLOSER UNIT); EP0919688 (Improvements In Or Relating To Valves); NZ195655 (DOOR CLOSER); NZ194125 (DOOR CLOSER OVERLOAD CURRENT REVERSES MOTOR); NZ193179 (DOOR CLOSER WITH FLUID FILLED DAMPER); NZ191931 (ADJUSTMENT DEVICE FOR ELASTIC DOOR CLOSER); NZ181676 (DOOR CLOSER: HYDRAULIC SYSTEM CONTROLS RATE OF CLOSURE); JP11081788 (DOOR CLOSER); JP11050736 (DOOR CLOSER); JP11050739 (STOPPING DEVICE OF DOOR CLOSER); U.S. Pat. No. 5,867,866 (Door Hinge With A Built-In Damper); U.S. Pat. No. 5,864,987 (Window Regulator With Improved Glider Assembly); U.S. Pat. No. 5,864,920 (Door Closer For The Non-Fire Side Of A Fire-Door Safety Installation); DE19734401 (Door And Window Closer Gas Spring); U.S. Pat. No. 5,862,630 (Door Closer); U.S. Pat. No. 5,862,569 (Door Closer Holding Plate); WO9902810 (DOOR CLOSER FOR GENERATING A SPEED-INCREASING LEAP DURING THE CLOSURE PHASE); WO9901635 (DEVICE FOR TRANSMITTING MECHANICAL CONTROL MOVEMENTS AND/OR ELECTRIC SIGNALS BETWEEN A DOOR ACTUATING DEVICE AND A DOOR CLOSER DEVICE OF A); FR2766513 (Hidden Hinge For Door Or Window Frame); WO9900574 (ARRANGEMENT FOR CONTROLLING AN ANGULARLY MOVABLE MEMBER); U.S. Pat. No. 5,855,039 (Delay Door Closer); WO9900573 (ARRANGEMENT FOR CONTROLLING AN ANGULARLY MOVABLE MEMBER); U.S. Pat. No. 5,850,671 (Door Closer); EP0889190 (Control Device For Door Closer); DE19728967; JP10325276 (DOOR CLOSER); JP10330061 (WEIGHT GUIDE OF DOOR CLOSER DEVICE); DE19725355; U.S. Pat. No. 5,845,360 (Door Closer Hold-Open Clip); AU6635998 (Door Closer Unit); JP10292720 (INDOOR DOOR CLOSER); JP10292722 (JOINT DEVICE BETWEEN ARMS IN DOOR CLOSER); JP10280772 (DOOR AUTO-CLOSER); U.S. Pat. No. 5,832,562 (Door Closer); U.S. Pat. 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No. 1,346,366 (Automatic Door-Closer); GB2293198 (A Door Latch Having A Serrated Striker Element); GB2257590 (MICROWAVE OPERATED AUTOMATIC DOOR); GB2214566 (Door Actuator); GB2204093 (Automatic Door Closer); GB2192426 (AUTOMATIC DOOR CLOSER); GB2190954 (Automatic Door Closer); GB2082248 (AUTOMATIC DOOR CLOSER); GB1400661 (AUTOMATIC DOOR CLOSER); FR2738865 (Door Closer To Facilitate The Automatic Closing Of A Door); WO9626344 (AUTOMATIC DOOR CLOSER AND PROCESS FOR MOUNTING THE SAME); WO9532145 (AN ANTI-CRUSH SAFETY DEVICE FOR AUTOMATIC DOORS, IN PARTICULAR FOR LIFTS AND ELEVATORS HAVING TRANSPARENT DOORS); WO9502107 (REVOLVING DOOR DRIVE); WO8809860 (AUTOMATIC DOOR-CLOSER); EP0757742 (AUTOMATIC DOOR CLOSER AND PROCESS FOR MOUNTING THE SAME): EP0635613 (A Sliding Door Stopper Device.); EP0390178 (Sliding Door Closer.); EP0368871 (AUTOMATIC DOOR-CLOSER.); EP0252554 (Automatic Door Closer.); EP0170940 (Operating Process Of A Door Closer, And Door Closer.); EP0166285 (Automatic Door Closer.); EP0137861 (Automatic Door Closer.); EP0120489 (Time-Controlled Window Closer.); EP0068963 (Automatic Door Closer Incorporating Braking Means.); DE19506355; DE19501565 (Mechanical Assembly System For Producing Door Or Window Drive); DE19500844 (Door Drive Esp. Door Closer For Automatic Door Closing And Manual Opening Of Door); DE4323152 (Swing-Door Drive); DE4323151 (Swing-Door Drive); DE4101640 (Automatic Door Closing Device With Hydraulic Damper—Has Pressure Compensating Chamber For Damping Fluid); DE4002889 (Body For Automatic Door Closer—Is Formed From Aluminum Or Plastics Extrusion); DE3906356 (Door Closer); DE3839188 (Lock For One-Handed Operation); DE3527287 (Automatic Closing System For Fire-Proof Cabinets); DE3411189 (Automatic Door Closer); DE3320609 (Automatic Door Closer With Electrohydraulic Stop Device); DE3315913 (Automatic Door Closer Having A Hydraulic Stop Device); DE3234319 (Automatic Door Closer); DE3225559 (Automatic Door Closer With A Hydraulic Stop Device); DE3117193 (Time-Controlled Window Closer); DE3116881 (Dynamic Door Closer); CZ278798 (AUTOMATIC DOOR CLOSER); CN2242312U (Automatic Door Closer); CN2213217U (Automatic Closer For Door); CN2193910U (Crankshaft Automatic Door Closer); CN2193909U (Automatic Door Closer); CN2143660U (Multifunction General Automatic Door Closer); AU4481096 (Automatic Door Closer And Process For Mounting The Same); AU1808888 (AUTOMATIC DOOR-CLOSER); CN1083161 (Automatic Door Closer); JP8126714 (DOOR CLOSER WITH AUTOMATIC CLOSING DEVICE); JP52081940 (AUTOMATIC DOOR CLOSER); JP57054684 (AUTOMATIC DOOR CLOSER); JP55022570 (FLAP DOOR AUTOMATIC CLOSER); JP56003777 (AUTOMATIC DOOR CLOSER); JP52121940 (AUTOMATIC DOOR CLOSER); JP57137581 (AUTOMATIC DOOR CLOSER); JP1187278 (AUTOMATIC CLOSER FOR AUTOMOBILE DOOR); JP52087845 (AUTOMATIC DOOR CLOSER). SUMMARY OF THE INVENTION One aspect of the present invention provides a power efficient door closing device whose design permits operation without a permanent line power connection, for example, a device whose primary door closing functions are principally powered from the initial opening of the door. Another aspect of the present invention provides a door closing device which stores door closure energy, and comprises a lock which prevents closure based on a doorway sensor, e.g., a sensor for detecting a subsequent person passing though the door. A further aspect of the invention provides an automatic or semiautomatic door control which is energy and space efficient, low cost, and which is readily installed without requiring permanent line wiring, while providing the benefits of an electronic control. The control therefore derives operational energy from manually initiated door movement, which is extracted and later employed to operate the control, close the door, or both. According to a preferred aspect of the invention, a door closer presents a counter force to door opening, and thus tends to maintain the door in a closed position, unless restrained. This serves two purposes; first, the force counters wind, other air pressure differences, and incidental jarring to change the position of the door. Second, the energy exerted by moving the door against the counter force is preferably captured and efficiently reutilized in a controlled manner. In contrast to simple hydraulic door closers, an intelligent control is provided which restrains door closure based on a sensor, rather than a simple immediate or time delayed closure. Known sensors for detecting persons in doorways, such as pad sensors in the walkway, passive infrared sensors, ultrasonic sensors, microwave sensors, optical sensors (imaging or non-imaging), or the like may be used, alone or in combination. Preferably, however, the sensor is part of or operates in close proximity to a door closer mechanism, and does not require separate wiring to a distant location. The sensor and control system typically requires a power source, which may be a battery, solar power, wired power, an energy draw from the door opening, or the like. In many instances, the control will be capable of operation at low power draw, and therefore battery power for the control will be possible. The use of a battery for powering the electronic control allows a reliable power source independent of door operation. On the other hand, powering large or power intensive actuators with a battery will likely result in short operating life and frequent service to replace the battery. Therefore, it is preferred that any power intensive actuators draw energy from the door operation. In low duty operation environments, such as homes or some offices and closets, battery power is a feasible option for actuator power, especially lithium batteries. Since the device is operative principally to delay closure of the door, the sensor need only be operative while the door is open, and thus the duty cycle of operation will typically be small. Further, since the control system need only block closure, a single valve or solenoid, magnetic clutch, or other device, may be used, requiring only a small amount of power. The device preferably mounts in the place of a known type of door closing device, to the door and door frame, and thus does not require a specialized installation. Other mounting options include in a space within the door, within the door frame, or as a part of one or more hinges. In a preferred design, a door closing mechanism includes a hydraulic cylinder damper coupled with a spring, acting together to slowly close the door. According to the present invention, a controllable valve is provided to selectively block flow of hydraulic fluid, halting the closure of the door. This valve is, for example, a latching solenoid actuator (i.e., drawing power only when switching states) acting on a piston having a cross-drilled hole. In one position, fluid flows through the hole. In the other position, the hole is not aligned with corresponding flow passages, and no flow occurs. As can be seen, the power required by the system is typically the power to operate the electronic control, the power required to operate the sensor, and the power require to operate the actuator. Assuming the door is operated 4 times per day over the course of a year, there are less than 1,600 cycles of operation. If the system has a quiescent draw of 100 μA, and an operating draw of 1 A for 2 seconds per closure, then the total power for operation over a year will be less than about 2 AH (0.875 AH quiescent plus 0.811 AH active). Therefore, under such use, a primary lithium battery could be employed to power the entire system, with an annual replacement cycle. On the other hand, as the duty cycle increases, the ability to reasonably provide a low maintenance reliable system running off battery power decreases, and power extraction systems become more cost efficient. A sensor mounted on the door closing device detects whether there is traffic within the doorway. If there is traffic, the door is restrained. Since people are conditioned for dumb (i.e., non-intelligent) door closing devices, and will be tempted to manually hold the door, a visual indicator, such as a blinking light emitting diode (LED) is provided to alert users that the device is operational. When the door is opened, a magneto generator may be operated, which charges a supercapacitor or rechargeable battery. A set of primary back-up batteries may also be provided. Since the magneto operation will damp the opening of the door, the hydraulic cylinder is provided with an asymmetric flow pattern, such that there is little hydraulic damping during door opening, since this would be redundant and would consume power which could be efficiently used by the magneto. The sensor is preferably a passive infrared sensor system, with sensitivity in both directions (i.e., ingress and egress), as well as a micropower microwave sensor, to detect existence and movement of objects (e.g., by radar techniques including phase shifts, Doppler shift and echo). A control is activated when the door is open, and begins reading sensor data. In a typical case, at least one person will pass through the door after it is opened. Thus, the control awaits this passage. In the rare case that no person passes through, or the sensors fail to read the person, the control allows the door to close after a preset period. If the control is inoperative, the door defaults to a standard mode that emulates a traditional door closing device. Thus, the control is preferably fail-safe. In addition, it is also possible for the control to provide additional functions, such as door locking, fire alarm mode, RFID and theft prevention using RF, magnetic, optical or other known techniques, room occupancy sensing (e.g., for public rest rooms), and wireless communications. After the first person passes through the door, the control analyzes sensor data to determine whether a second person is passing through the doorway. If so, then the door remains restrained from closing until the doorway is clear. A visual indicator is provided to indicate that the door is restrained, and preferably also indicates when the door is about to begin closing with a different signal, for example a different visual signal and possibly an additional audio signal. A voice or sound sensor system may also be provided to allow the door to be instructed. For example, a speaker independent voice recognition could be programmed to detect a number of variants of “hold door!”, including foreign languages. Likewise, an instructed override could also be programmed for “close door!”, which would override operation in extenuating circumstances, for example where a dog is meant to be left outside, but follows its master. Likewise, the sensor or control may be adapted or programmed to distinguish between types of operating conditions. As stated above, in a preferred high duty cycle design, the door opening operates a mechanical to electrical energy transducer, e.g., a magneto. In a typical design, as the door is opened, a gear train rotates an armature within a magnetic field, generating an electrical current. This electrical current is either directly, or through a power converter, used to store charge in a large-valued capacitor or rechargeable battery (or hybrid type device), for subsequent operation of the system. The opening of the door also activates the control, which begins monitoring the sensors. As the door opens, there will typically be a person on one side of the doorway. (If there is no person detected, the system may be programmed to interpret this as a wind gust, and the door opening may be restrained. In this way, the normal closing force may be limited to a level less than the wind gust force). The sensors detect this person, and monitors as he or she passes through the door, and out of the doorway. During this period, the closure is prevented. After the initial person passes through the doorway, the sensors determine whether there is another person entering the doorway. If so, the closing device remains locked open. If not, the valve is released, and the hydraulic closing device allowed to close the door. In an alternate embodiment, the hydraulic damper is dispensed with, and the magneto serves to damp the opening and closing. The load on the magnetic may be controlled to provide various damping factors. The control, in this case, is preferably a magnetic clutch to stop the armature from rotating, or a solenoid brake operating on a displaceable rod that moves with the door. In this case, in order to extract sufficient energy from a door opening event to complete a subsequent door closing event, the force applied for door opening will generally exceed the door closing force. Otherwise, a supplemental source of power may be provided. For example, in an office ceiling, there are often ballasts for fluorescent lighting. These ballasts emit a substantial amount of magnetic waves, which may be captured by a coil antenna and stored. Likewise, exterior doors may receive sunlight, which may be converted with a solar cell into electric power. In order to provide resilience against externally applied forces, a bypass or friction plate is provided to prevent damage to the closing device. A battery backup, for example having alkaline or lithium batteries, is provided in case the charge on the capacitor is insufficient for operation. The audible or visual indicator may provide a low battery indication. These batteries also allow some operation of the device while the door is closed, for example to periodically self-calibrate sensors for a non-operating condition. It is understood that the present invention therefore provides, according to a first embodiment, an improvement for a standard door closer in the manner of an intelligent control, which, for example, may be retrofitted to existing door closers or form the basis for an improved design. In a second embodiment, an electrical system replaces the traditional hydraulic system to provide improved performance, enhanced control capability, and potentially more cost effective manufacture. The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention as will be described. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the following Detailed Description of the preferred embodiment. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and the advantages thereof, reference should be made to the following Detailed Description taken in connection with the accompanying drawings in which:); FIG. 1 shows a door-closing device according to a first embodiment of the present invention mounted to a door in a door frame; FIG. 2 shows a sensor configuration detail according to the embodiment of FIG. 1 ; FIG. 3 shows a side view of a second embodiment of the present invention, having a hinged sensor module; FIG. 4 shows a schematic diagram of a generic control system according to the present invention; FIG. 5 shows a mechanical configuration of a third embodiment of the present invention; FIG. 6 shows a mechanical configuration of a fourth embodiment of the present invention; FIG. 7 shows a mechanical configuration of a fifth embodiment of the present invention; FIG. 8 shows a mechanical configuration of a sixth embodiment of the present invention; FIG. 9 shows a flow chart of the control system operation according to the present invention; FIGS. 10A and 10B show a detail of a valve in a magnetically controlled damper, in the On and OFF states respectively; FIG. 11 shows a schematic view of an electronically controlled, hydraulically damped door closer according to the present invention; and FIG. 12 shows a schematic view of a hydraulically damped door closer with an intelligent hold-open device according to the present invention. Similar reference characters refer to similar parts or steps throughout the several views of the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description sets forth numerous specific details to provide a thorough understanding of the invention. However, those of ordinary skill in the art will appreciate that the invention may be practiced without these specific details. In other instances, well-known methods, procedures, protocols, components, and circuits have not been described in detail so as not to obscure the invention. The invention provides a control system for a passive door closing system to alleviate the problem of the requirement for manual efforts, sometimes significant, in order to overcome the tendency of an automatic door closing mechanism to close the door immediately (or after a preset delay) after being opened. Such door closers are provided to prevent insects and debris from entering a doorway, and to maintain controlled climates separate from uncontrolled climates. The force on the door is typically sufficient to keep the door closed under windy conditions and against possible air pressure differences seeking to open it. Since the door is typically 2.5 feet by 7 feet, even a low 0.05 psi pressure differential is sufficient to create a 126 pound force. Likewise, the door must be damped, since the spring would tend to slam the door closed, and an undamped door when pushed open abruptly might hurt an unseen person on the other side. A sensor is provided to sense a person in or approaching the doorway, and preferably distinguishes a person leaving the doorway or congregating in the vestibule. These may be distinguished by a motion analysis. The system is powered by a door opening, which typically provides a significant force exerted over a short period of time. Part of this force is to provide potential energy for the door closing mechanism to later close the door, and part is normally lost in a damping mechanism. According to the present invention, the damping forces may be captured and stored as electrical energy to power the control system. The control system may be relatively simple: it receives sensor data, and makes a decision as to whether to delay door closure, and then controls an actuator to either close the door or to permit door closure. Other ancillary functions are optional. Since electronic devices have become quite sophisticated, and doors are located in strategic locations, the door closer may be suitable for integration with various electronic systems, including theft prevention, RFID, person recognition, portal inventory, fire alarm condition, alarm or security system sensing and/or control, occupancy sensing, pet control, or the like. The control system controls an actuator, for example a solenoid valve, clutch/friction plate, electro-rheological phenomenon, catch, or other type of mechanism. Typically, an electronic control system will control an electrical transducer, which is typically an electromagnetic or piezoelectric system. Other possibilities include electrochemical (e.g., hydrolyzing a liquid to produce a gas, which exerts a pressure. To reverse, the gas may be explosively or catalytically recombined), and electrothermal (e.g., heating a shape memory alloy above its transitional temperature to cause a shape reconfiguration). A backup battery is provided to provide power in case the capacitor discharges or fails to fully charge. For example, if the door is opened very slowly, the voltage generated by the magneto will be insufficient to charge the capacitor. Likewise, a long delay between opening and closing may allow the capacitor to self-discharge. As shown in FIG. 1 , a door 1 is provided in a door frame 3 , having a doorknob 2 . A door closing mechanism 8 is provided at the top of the door 1 , and connected to the door frame 3 , by a linkage including arms 5 , 7 and hinge 6 , held to the door frame by a mount 4 . The door closing mechanism 8 includes a system for returning the door to a closed position, a selective control for delaying door closure while a person or object is in the doorway, a sensor housing 11 , having a sensor 12 for detecting the presence of a person or object in or near the doorway. The door closing mechanism also include a feedback device, e.g., a set of light emitting diodes (LEDs) 9 , which provide an indication that the device is operative to hold the door open, and therefore that it need not be manually held for a next person. These LEDs 9 may also provide indication of a failure condition, such as low battery, watchdog timer timeout, or mechanical or electronic failure. FIG. 2 shows in greater detail an embodiment of the sensor housing 11 , which in this case is separated from the door closing mechanism 8 by a coiled wire 10 . In this embodiment, two sensors are provided; a passive infrared (PIR) sensor 13 , and a microwave sensor having a microwave antenna 15 . The sensor housing 11 may also include a set of LEDs 14 , to indicate that the sensor has sensed an object or person, or to otherwise indicate the status of the system. In this case, since the sensor housing is mounted to the door frame 3 , it may optionally be wired to receive line power, which may be provided to the door closing mechanism 8 through the coiled wire 10 . It is thus clear that a separation from line power is not a negative limitation on all embodiments of the invention, and in fact, where accessible, line power is a quite efficient power source. However, one of the advantages of the present design is that the operational principles are compatible with non-line powered operation. In this embodiment, the sensor housing is mounted in predetermined position on the side opposite where the door opens. The sensors 13 , 15 , are this in fixed position, and may be aligned with the normal path of travel through the doorway. The PIR sensor 13 is sensitive to a change in heat patterns, i.e., infrared wave emissions, through a lens portion, and, for example, includes a sheet of pyroelectric material, such as polyvinylidene fluoride (PVDF). Alternately, the sensor system could include an optical sensor, for example an imaging complementary metal-oxide-silicon (CMOS) or charge coupled device (CCD) sensor. In that case, the LEDs 14 could advantageously provide illumination. Likewise, the LEDs (as laser diodes) could form part of a LIDAR sensor system to detect object range and motion. The microwave sensor emits a signal through microwave antenna 15 . This sensor can detect object presence, range, and/or motion, depending on the control system and implementation. Preferably, it is used to detect object presence and as a Doppler sensor to detect velocity with respect to the antenna sensitivity pattern. The sensor system is preferably inactive while the door is closed, conserving power. As the door is opened, which may be detected in any suitable manner, the sensor become active, and remain active until the door is closed or is beginning to close. In some cases, the control and infrared sensor may be continually active, since these are relatively low power components. This permits control over operation prior to door opening. For example, the control may lock the door when no sensed person is nearby, but when a person is in the doorway, allow the person to open the door. The control may authenticate the person to implement controlled access, through optical feature recognition, RFID, security token, fingerprint, iris or other biometric recognition technique, voice recognition, password, PIN, or other control technique. The door opener may receive an optical, magnetic or RF signal to receive control instructions from another system, and may provide a platform for the mounting of antennas for wireless networks and the like. FIG. 3 shows an alternate embodiment of the invention, in which the sensor housing 24 is mounted on an arm 23 hinged by hinge 18 to lift up with respect to mounting 17 as the door is closed and down as the door is opened. This embodiment extends the faces 25 , 26 of the sensor below the top of the door frame 3 to sensor objects and people in the doorway. The arm 23 is connected though arms 20 , 22 and hinge 21 to the arm 5 of the door closing mechanism. FIG. 3 also shows that the mount 4 may be replaced with an “L” shaped member 16 to fit around a corner of the door frame 3 . FIG. 4 shows a generic embodiment of a control system, i.e., one which includes a number of optional features, not all of which are provided or necessary in all cases. A control 40 provides implements the logic necessary for intelligent operation, and is, for example, a microcontroller of known type. Preferably, the microcontroller includes power driver capabilities, minimizing the requirement for external driver circuitry, but is otherwise of a low power design. It is understood, however, that any sort of logic, including discrete devices, various levels of semiconductor integration, or powerful microprocessors, may be used in the control. Further, while it is preferred that the control be included within and integral to the door closing mechanism, it may be provided separately, for example in a sensor housing or as a part of a centralized control system. The control 40 may therefore optionally have a communications interface 58 . The control 40 generally communicates with a sensor network 41 , which, as shown in FIG. 4 may include one or more sensors, for example, a PIR sensor 42 , a microwave/Doppler sensor 43 , optical sensor 44 (imaging or non-imaging), a pressure switch 45 (for example, a door mat or surface on the door 1 ), a microphone 46 , or a remote control/key 47 interface. In the later case, the door closing mechanism may also serve as a lock for the door, or be manually operated or overridden through, for example, an infrared or radio frequency interface. It is noted that this interface may be consolidated with the communications interface 58 . As the door 1 is opened, generally energy is stored for later closing the door 1 . The energy storage mechanism also supplies a force which prevents the door from opening rapidly. In a prior art design, this energy storage is typically in a spring or pneumatic chamber. While these are used in various embodiments of the invention, one embodiment of the present invention captures some of the energy supplied during door 1 opening to supply power for control 40 system operation. For example, magneto 52 is rotated during door opening, to supply an electrical charge to super capacitor 50 and/or battery 51 . The control 40 may intermediate, for example controlling an electrical impedance of the magneto to damp door 1 motion. The magneto 52 may also be operated as a motor to return the door 1 to the closed position, for example replacing the traditional spring and damper of prior designs. It is noted that, in order to provide a fail-safe design, the system preferably does not rely on active devices for door 1 closure. Thus, a mechanical or pneumatic spring (not shown in FIG. 4 ) cooperates with a damper to ensure that the door closes in a predictable and controlled fashion. A door open switch 48 and door closed switch 49 sensor may be provided. The door closed switch, for example, may be used to turn on and off the system, while the door open switch 49 may be used to control a damping factor of the door 1 through the damping control 53 . When a person or object is detected in the doorway by the sensor network 41 , a damper control 53 or door stop 54 (or both) are activated to block or impede door 1 closure. The door remains open until the obstruction is clear, as determined by the sensor network 41 , or another condition causes the door to close, for example, a watchdog timer inherent in the control 40 expires (a timeout condition), or a signal is received through the communications interface 58 or remote control/key sensor 47 . A feedback system 55 may be provided with audible 57 and/or visible 56 indicators, to indicate the status of the system. For example, low battery, failure (mechanical or electronic), object sensed, timeout, and/or door restraint active. FIG. 5 shows an embodiment of the invention having a so-called coil-over design damper 66 and spring 67 (the spring 67 may also be housed within the damper 66 ). In this case, a piston rod 65 has rack gearing on an end portion, and is withdrawn from the damper 66 as the arm 7 is rotated, thus rotating mating gear 63 , through connecting shaft 64 . Connecting shaft 64 also connects with magneto 61 through a gearhead 62 reducer, such that the magneto 61 produces a usable current for charging a rechargeable battery pack 51 ′ and/or capacitor (not shown). The terminal movement of the piston rod 65 is detected by a set of microswitches 48 ′, 49 ′. The control 40 receives input from a sensor module including PIR 42 and microwave 43 sensors, which, in this case, are provided on the bottom of the door closing mechanism 8 housing. FIG. 6 differs from FIG. 5 in that this embodiment provides electrically controlled damping of the door 1 , with mechanical retraction through spring 67 ′, acting through cable 70 and winch 71 . Arm 7 acts through shaft 64 , mounted on bearings 74 , 75 , to turn gear 72 . Gear 72 , in turn, acts on gear 73 to rotate the armature of magneto 52 . The electrical energy produced by the magneto 52 is stored in storage capacitor 50 ′ to power the control 40 . A backup battery 51 ′ is provided if the power available from the storage capacitor 50 ′ is insufficient. In this case, the sensor housing 11 , including the sensor network 41 having PIR sensor 42 and microwave 43 sensor, is shown separated from the door closing mechanism 8 housing. FIG. 7 shows a still different embodiment, wherein arm 7 is rotationally connected to shaft 83 , which acts through planetary gearhead 81 with motor 80 . A brake 82 , and shaft sensor 84 are provided. In this case, a fully active design is provided. The motor 80 , during door 1 opening, may act as a generator to charge super capacitor 50 ′, or act as a power assist to open the door. Once the door is open, the brake 82 is engaged, to hold the door in position. When the doorway is clear, the brake 82 is released, and the motor 80 driven to close the door. In this case, the power supply 51 ″ may be a battery or line power. The sensor 84 is used to determine whether the door is being pushed or held open, this providing feedback to prevent the motor 80 from fighting a person manually operating the door. Likewise, the sensor may be used as part of a servo or brushless motor design. FIG. 8 shows a still further embodiment of the invention. In this case, a servo motor 90 , with optical encoder 91 , drives shaft 92 with worm gear 94 , meshing with gear 93 attached to shaft 64 , linked to the arm 7 . A torque sensor 95 senses a manual force on the door 1 , which is then used by control 40 to drive the servo motor 90 . After the force ceases, the control 40 maintains the door 1 in the open position until the doorway is cleared, and then closes the door by rotating the servo motor 90 in the opposite direction. If an obstruction is sensed by the torque sensor, the control stops the door 1 closure. In this case, a battery 51 ′ system or other power supply is necessary, since no energy is stored from door opening. Alternately, an asymmetric drive may be provided, using the servo motor 90 only for door closure, and using a magneto to store energy from door 1 opening. FIG. 9 shows a flow chart of control 40 system operation. Initial, at start 100 , the device is typically powered down. An opening of the door is detected 101 , and the sensor(s) and control turned on 102 . As the door is opened, energy is stored 103 . After the door is opened, it is held open 104 . The control then uses the sensor network to determine whether the doorway is clear 105 . If it is clear, the door is allowed to close 107 , the system shuts down 108 , and the process stops 109 . If the sensor network does not indicate that the doorway is clear, a watchdog timer is referenced 106 , to determine whether a maximum door retention time is exceeded. If it is exceeded, the door is allowed to close 107 , preferably with an audible or visual advance warning. If the maximum door retention time is not exceeded, the door is held open 104 , and the sensing process is repeated to determine whether the doorway is clear 105 . The sensor network 41 may be operative, for example, once per second, to save energy. The maximum door retention time is, for example, 20 seconds. FIGS. 10A and 10B show a valve detail of a magnetically controlled damper according to the present invention. A magnetorheological fluid, for example a magnetic powder suspended in a viscous oil, is provided. During device operation with a low damping coefficient, the fluid 200 flows viscously through a relatively large port 201 , within a conduit 202 . See, Jolly, Mark (Lord Corporation), “Pneumatic Motion Control Using Magnetorheological Technology”, SPIE (2001), expressly incorporated herein by reference. In this case, a displaceable permanent magnet 203 is retained in an ON (flowing) position by a fixed permanent magnet 204 in a guide 205 . A coil 206 is activated to produce a magnetic field in the guide, to selectively control displacement of the displaceable permanent magnet 203 away from the fixed permanent magnet 203 , toward the conduit 202 , which causes an apparent sharp increase in the viscosity of the fluid 200 , thereby reducing flow rate in the OFF (non-flowing) state. Thus, fluid flow rate can be simply controlled, with a relatively simple electrically controllable and sealed device. This damper may be used as a primary effector for the control, for example to maintain the door in an open position as the door stop 54 , by effectively blocking fluid 200 flow, or as a secondary control over the rate of fluid flow through as the damper control 53 , or as both. For example, a spring inserted between the displaceable permanent magnet 203 and the conduit 202 might permit proportional operation. FIG. 11 shows a schematic view of a hydraulically damped door closer according to the present invention. Typical commercial door closers for sale in the U.S Domestic market are of two types: those for fire doors, which are generally rated by Underwriters Laboratories (UL), and which have no means for locking the door in an open position, and unrated door closers for applications in which fire codes and the risk of fire hazard in the event that the door is held open is not a substantial issue. See, for example, Ryobi 8800 Series, D1550 Series, D2100 Series, D3550 Series, Sargent Bradford Series. In order to provide an efficient design, the two type of door closers generally share common parts, and for example, have a different arm (called a hold-open arm) for the unrated application. On the other hand, some door closers have an internal hold-open, as an option for the main body of the closer. The hold open feature not only poses a fire hazard under various circumstances, but also defeats a number of advantages of the presence of a door closer. Many hydraulically damped door closers for commercial application have three (or more) adjustments; a first setting 201 for adjusting the initial door closure rate, a second adjustment 202 for setting a mid-swing door closure rate, and a backcheck adjustment. The door closure rate settings are established by a set of screw adjustable bleed valves. The initial door closure rate is typically higher than the mid-swing rate, so in order to maintain the door in an open condition, all bleed valves would have to be blocked. (In order to provide a fail-safe mode, the minimum door closure rate may be set at a very slow rate, such as 1-5 minutes, instead of locked.) Therefore, the present invention provides a hydraulically damped door closer which provides one or more electronically controlled bleed valves (which may be mechanically adjusted to control respective closure rates). These valves may be linear solenoids (latching or non-latching) 201 , 202 , or rotary valves. In a held-open condition, a solenoid is activated to maintain the door in an open position by blocking flow of hydraulic fluid through the orifice. In a closure condition, the hydraulic fluid flows according to the normal arrangement of passages. Generally, door opening bypasses the damping mechanism and transfers energy to a spring 203 . According to the present invention, the electronic control therefore bypasses or supplements the relatively simple “hydraulic logic” to provide a higher intelligence. Examples of this intelligence include object sensing in a doorway, fire or smoke detection (and therefore door closure and/or alarm), remote activation, room occupancy sensing, and the like. In a first embodiment, a spring biased solenoid actuator is linked to a needle which controls flow through a restricting orifice 201 , 202 . The control 210 holds the actuator 201 , 202 in the active and therefore hold-open state for so long as an object is in the doorway, or other condition exists for which the door should be held open. This method is fail safe, since a battery failure would result in default hydraulic door closure. A control 210 failure which activates the solenoid actuator 201 , 202 would likely drain the battery 211 over a few hours. Thus, a fire safety rating or special exemption may likely be obtained. Since power is required to maintain the solenoid actuator 201 , 202 in an activated state, a magneto generator 204 driven by the door opening through gear 205 is preferred. In a second embodiment, the actuator employs a latching armature. In this case, it is possible for the battery to fail with the unit held in the open position; therefore this embodiment generally includes a base bleed which causes the door to close within 1-5 minutes, and so provide a graceful and fail safe mode. This type of system may have lower battery drain than a system in which continuous power is required to restrain door closure. In a third embodiment, shown in FIG. 12 , a collapsible mechanical toggle linkage 220 is reset each time the door is opened by extension of a moveable member 221 within the door closer. See, U.S. Pat. No. 6,031,438, expressly incorporated herein by reference. The control 222 then generates a signal which activates a solenoid 223 which pulls an armature 224 , which displaces a seer pin (not shown in FIG. 12 ) and collapses the toggle linkage 220 when the door closure is to be activated, which allows the normal hydraulic door closure mechanism 225 to operate. In this case, only a single actuator pulse is required to close the door. On the other hand, this acts as an automatic hold-open, and thus would likely be applicable especially for non-fire safety rated operation. As can be seen, the control 222 may receive, for example, an external signal to trigger door closure, such as a fire alarm or a timer. A manual reset may also be provided to trigger the door closure in case of control 222 failure. The door closer may also include a variety of sensors and/or sensor inputs, of particular importance being a fire and/or smoke detector, or remote indication of such conditions. A remote communication may take place by means of wires, radio frequency, audio signals, infrared, optical signals or the like. Thus, the door closer may watch or listen for activation of proximate fire alarms, and thus need not be permanently wired. Typically, this design will also incorporate an object or person sensor in accordance with the above examples, but need not. It is noted that while hydraulic damping is preferred, other damping means may be provided, especially if electronically controlled. In particular, a magneto which spins during door closure (and possibly opening), having a controllable (or fixed) load, would damp closure. Likewise, a magnetically activated clutch (linear or rotary) could be controlled to regulate closure speed, and effect damping. From the above description and drawings, it will be understood by those of ordinary skill in the art that the particular embodiments shown and described are for purposes of illustration only and are not intended to limit the scope of the invention. Those of ordinary skill in the art will recognize that the invention may be embodied in other specific forms without departing from its spirit or essential characteristics. References to details of particular embodiments are not intended to limit the scope of the claims.

A method for controlling a door, comprising the steps of storing energy during a manual opening of a door, sensing an object within a doorway, selectively applying a force derived from the stored energy, to close the door, based on the sensing of an object in the doorway. The closure is preferably controlled by an electronic control. A door closing device comprising an energy storage device for storing energy during door opening and releasing the stored energy to subsequently close the door, a damping system for damping a closure of the door, a sensor for detecting an object within a doorway, having an output, a controllable device for selectively restraining the energy storage device from closing the door, and a control system for controlling the controllable device based on the output.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority of the German patent application 102 34 756.5 which is incorporated by reference herein. FIELD OF THE INVENTION [0002] The invention concerns an autofocus module for a microscope-based system. The invention concerns in particular an autofocus module for a microscope-based system having an objective that defines an image beam path which is perpendicular to a surface of a specimen and can be focused thereonto, and having an illumination beam path that encompasses a light source for illumination of the specimen. BACKGROUND OF THE INVENTION [0003] German Patent DE 32 19 503 discloses an apparatus for automatic focusing onto specimens to be viewed in optical devices. After reflection at the surface of a specimen, the reflected measurement light beam bundle passes through a pinhole after reflection at a splitter mirror. A portion of the measurement light beam bundle is reflected out by means of a fully mirror-coated surface, and after passing through a slit aperture is directed onto a differential diode. In the focused state, the focus is located between the two diodes. In the event of defocusing, the measurement spot drifts onto one of the two diodes, which are connected to corresponding control means. The control means adjust optical or mechanical means of the microscope in order to bring the measurement spot back between the two diodes, and thus reestablish the focus position. European Patent Application EP-A-0 124 241 discloses a microscope having an automatic focusing device. The microscope encompasses a memory device for saving the data from the objectives that are used in the microscope. Also provided is a control device which monitors and regulates the various microscope functions. Another of the tasks of the control device is to move the focusing stage. A CCD element, which receives an image from the particular selected objective and, together with a computation unit, determines the image sharpness based on optimum contrast, is provided as the image acquisition device. The objective data of the objective presently in use must be taken into account when determining the optimum sharpness. Those data are, as mentioned above, stored in a memory. [0004] German Unexamined Application DE 41 33 788 furthermore discloses a method for autofocusing of microscopes, and an autofocus system for microscopes. The image of a specimen or of a pattern reflected onto the specimen is conveyed to two areas on a detector or to two different detectors; in the focused position, one image is produced in front of one detector, and one image behind the other detector. The image sharpness states on the detectors are converted into electronic signals, whose difference is used to focus the objective. The distances of the image or of the respective pattern from the respective detectors are adjustable. Deliberate offset settings, as well as “IR offset” correction settings, can be implemented. [0005] A problem in the context of automatic focusing in microscopes, for the examination of specimens having several focal planes, is that the autofocus system does not know which plane it should sharply focus onto. The autofocus system can focus onto only one of the planes, and it can easily happen that the autofocus system loses the focal plane and jumps to another as it corrects. The multiple planes result, for example in the semiconductor industry, in the context of different topological steps or multiple photoresist layers. In conventional microscopy and in confocal microscopy, there are also multiple layers that can be focused on. In samples equipped with coverslips, these can be the upper side of the coverslip with the interface to air, or the underside of the coverslip with the interface to the sample. SUMMARY OF THE INVENTION [0006] It is accordingly the object of the present invention to create an autofocus module for a microscope-based system with which multiple focal planes can be detected at one time. In addition, it is possible ultimately to focus on a selected focal plane. [0007] The object is achieved by way of an autofocus module for a microscope-based system comprising: [0008] an objective that defines an image beam path which is perpendicular to a surface of a specimen [0009] an illumination beam path that encompasses a light source for illumination of the specimen, [0010] a light source for generating a measurement light bundle for determining a focus position; [0011] an optical means for splitting the measurement light bundle in such a way that an eccentrically extending measurement light beam bundle is created; [0012] a first dichroic beam splitter is provided in the image beam path of the microscope-based system, which couples the measurement light beam bundle eccentrically into the microscope-based system and directs it onto the surface of the specimen; [0013] the optical means directs onto a detector element a measurement light beam bundle remitted from the microscope-based system; and [0014] a cylindrical lens between the detector element and the optical means. [0015] The autofocus module has the particular advantage that there is provided between the detector element and the optical means a cylindrical lens that, for determination of the focus position, generates a line that is imaged onto the detector element. In addition, means are provided which pivot the detector element about an axis, so that the detector element is inclined with respect to a plane defined by the surface of the specimen, and its inclination is adjustable. Furthermore, the detector element can be pivoted or adjusted exclusively and only about an axis that is parallel to the X axis of a coordinate system. The optical components of the autofocus module are combined in a housing. The optical elements in the module are thereby pre-aligned, and it can be quickly attached to an existing microscope-based system. The detector element can be embodied as a two-dimensional area sensor or constituted by at least two linear sensors arranged parallel to one another. A laser light source that emits IR light as the measurement light is used in the autofocus module as the light source. This is advantageous because the specimen is not influenced thereby. A computer or a control system are connected to the microscope-based system and the module, serving to control the detector element in the module and the microscope-based system. Control is of the inclination of the detector element is important because means are provided which perform an adjustment of the inclination of the detector element. In addition, the inclination of the detector element can be modified during measurement; this results in a change in the sensitivity of the measurements performed. BRIEF DESCRIPTION OF THE DRAWINGS [0016] Further advantages and advantageous embodiments are the subject matter of the description below of the Figures, in whose presentation accurately scaled reproduction was dispensed with in favor of clarity. In the individual drawings: [0017] [0017]FIG. 1 is a partial side view of the beam paths of an optical device or a microscope-based-system to which an autofocus module is attached; [0018] [0018]FIG. 2 is a detail view of the measurement light beam bundle striking the measurement sensor; [0019] [0019]FIG. 3 shows a further embodiment of the detector element; [0020] [0020]FIG. 4 shows the autofocus module in the focused state, the measurement beam being focused onto one spot; [0021] [0021]FIG. 5 shows the use of a cylindrical lens which generates, from the measurement spot, a sharp line that is imaged onto the detector element; [0022] [0022]FIG. 6 shows that by tilting the detector element, the line is imaged sharply at multiple spots if multiple focal planes are present on the specimen; [0023] [0023]FIG. 7 a shows one (or more) transparent films, one above another, which constitute the different focal planes; [0024] [0024]FIG. 7 b shows a stepped structure on the specimen which is small compared to the measurement spot on the specimen; [0025] [0025]FIG. 8 a shows an embodiment of a further optical element that additionally widens the measurement light beam bundle; and [0026] [0026]FIG. 8 b shows an additional embodiment of a further optical element that additionally widens the measurement light beam bundle. DETAILED DESCRIPTION OF THE INVENTION [0027] [0027]FIG. 1 depicts a vertically extending image beam path 10 of a microscope-based system 1 . Microscope-based system 1 comprises a light source 6 which emits light into illumination beam path 11 . Microscope-based system 1 serves to illuminate a specimen 20 which defines a surface 21 that is located in the focal plane of microscope-based system 1 . The light of illumination beam path 11 first passes through an objective 2 and strikes surface 21 of specimen 20 . A certain portion of the light is reflected from surface 21 of specimen 20 and passes first through an objective pupil 3 . The beam reflected from surface 21 of specimen 20 passes, in image beam path 10 , through a dichroic splitter mirror 12 that has a 50:50 ratio in the visible region and high reflectivity in the IR. The light of the image beam path then traverses a tube lens 4 , and an image of specimen 20 is generated in intermediate image plane 5 . The light in image beam path 10 then travels to an eyepiece (not depicted). [0028] In the situation depicted, illumination beam path 11 of the microscope-based system extends horizontally. Light of illumination beam path 11 emerges from a light source 6 . After leaving an optical system 7 , the light passes through an aperture stop 8 in whose plane is arranged a pinhole slider (not depicted) that contains at least two pinholes of differing dimensions. With this pinhole slider, an aperture stop 8 adapted to the measurement with the microscope-based system can be inserted, in manual or motorized fashion, with position response. [0029] The light of illumination beam path 11 then passes through a second dichroic beam splitter 13 which has the greatest possible transmissivity for the visible light coming from light source 6 , and the greatest possible reflectivity for IR light. A mark whose function is explained below is located in the plane of field diaphragm 9 . After passage through a lens 14 , the light of illumination beam path 11 strikes first dichroic beam splitter 12 , from which the reflected portions are deflected toward specimen 20 . [0030] A laser autofocus system, which in the exemplary embodiment depicted here is combined with all the necessary optical components into a module 30 , is provided for adjusting the focus. Module 30 is surrounded by a housing 25 that is depicted symbolically in FIG. 1 as a dashed-line box. Module 30 can be inserted, for example, into an existing optical illumination system such as the one described for incident-light microscopes e.g. in German Utility Model 79 17 232, snap-lock means known per se ensuring accurately aligned positioning of module 30 in illumination beam path 11 . [0031] A (preferably pulsed) laser light proceeds from a laser light source 31 that, in the embodiment depicted, is embodied as a laser diode. Advantageously, IR light is used as the measurement light, since it does not have a disruptive influence on the microscopic image of specimen 20 . A measurement light bundle 32 is directed, via a stationary lens 33 and then via a lens 34 that can be displaced in manual or motorized fashion in the axial direction as defined by dashed double arrow 35 , onto second dichroic splitter mirror 13 , which is arranged at the optical interface of the beam paths of measurement light bundle 32 and illumination beam path 11 . An image of laser light source 31 is generated in the intermediate image plane in which field diaphragm 9 is positioned. [0032] Laser light source 31 is imaged onto surface 21 of specimen 20 in a measurement spot 16 . One half of a pupil 37 is covered so that in the event of defocusing, measurement spot 16 drifts on surface 21 of specimen 20 . The geometric covering of one half of measurement light bundle 32 is achieved using a combined optical component, for example a deflection prism 38 , which is inserted halfway into measurement light bundle 32 at the level of pupil 37 . Deflection prism 38 contains a fully mirror-coated prism surface 19 . The portion of measurement light bundle 32 that is not prevented from propagating by the arrangement of deflection prism 38 is labeled in FIG. 1 with the reference character 32 a . With eccentrically extending measurement light bundle 32 a of illumination-side measurement light bundle 32 , eccentrically extending portion 32 a therefore proceeds into objective pupil 3 (substantially) parallel to image beam path 10 of microscope-based system 11 . [0033] After reflection at surface 21 of specimen 20 , remitted measurement light beam bundle 32 b passes lens 14 , and after reflection at second dichroic splitter mirror 13 , the light of remitted measurement light bundle 32 b strikes fully mirror-coated prism surface 19 of deflection 38 . Remitted measurement light beam bundle 32 is then reflected out by fully mirror-coated prism surface 19 of deflection prism 38 . After total reflection at a prism surface 40 , and after passing through optical system 41 , the beam is widened by a downstream cylindrical lens 42 before striking a detector element 43 . Detector element 43 can be embodied as a two-dimensional area sensor, e.g. as a CCD or CMOS sensor. Detector element 43 can be tilted. Provided for that purpose are displacement means 46 and 47 , which incline detector element 43 with respect to a plane defined by the surface of specimen 20 . The plane thus defined by inclined detector element 43 is oblique (not perpendicular) with respect to the incident remitted measurement light beam bundle 32 b , so that in the focused state, remitted measurement light beam bundle 32 b is imaged sharply only at the center. A computer 80 or a control system are connected to microscope-based system 1 and to module 30 . Computer 80 serves to control detector element 43 in the module and microscope-based system 1 , and to acquire corresponding data, and also to perform the displacement or tilting of detector element 43 . Adjustment of the focus can also be performed by computer 80 via a motor 23 which actuates the Z drive of a microscope stage 22 . Motor 23 receives from computer 80 the correspondingly processed signals from detector element 43 . These signals serve for control purposes and to adjust the focus, and are conveyed to motor 23 . [0034] In order additionally to achieve a beam widening of measurement light beam bundle 32 , a further optical element is provided, between deflection prism 38 and lens 34 , which additionally widens measurement light beam bundle 32 . As depicted in FIG. 8 a , the optical element can be an axicon 53 . A first and a second axicon 53 a and 53 b are mounted on a glass plate 54 as support. First axicon 53 a acts on the eccentrically extending measurement light beam bundle 32 a , and second axicon 53 b acts on remitted measurement light beam bundle 32 b . The exemplary embodiment of FIG. 8 b shows a toroidal lens 57 as the optical element. Toroidal lens 57 is a lens element that is curved into a ring. The opening of the ring is equipped with an opaque stop 58 . The effect of toroidal lens 57 is comparable to that of axicon 53 . [0035] [0035]FIG. 2 is a detail view of measurement light beam bundle 32 b striking detector element 43 . Cylindrical lens 42 normally converts measurement light beam bundle 32 b , at the focus, into a line (see FIG. 4). In the depiction in FIG. 2. detector element 43 is pivoted about an axis parallel to the X axis of the coordinate system. Plane 44 spanned by the X and Y coordinate axes is parallel to surface 21 of specimen 20 . Tilting of detector 43 about the X axis causes the line (FIG. 4) to be imaged sharply at only one spot 45 (only one plane of sharpness present in specimen 20 ). When specimen 21 is displaced in the direction of the Z axis, measurement light beam bundle 32 b shifts on detector element 43 . The direction of the shift is indicated by double arrow Px. In contrast to a conventional laser autofocus system, the tilting of detector element 43 still produces a single spot on detector element 43 despite the change in the position of surface 21 of specimen 20 , and in the defocused state the distance between surface 21 of specimen 20 and the focal plane can be ascertained by analyzing the position of spot 45 on detector element 43 . If detector element 43 is tilted, with respect to the plane defined by the surface of the specimen, by an angle that is attainable by displacement of the detector element about the one axis parallel to the X axis and the one parallel to the Y axis. With a detector element 43 tilted in this fashion, measurement light beam bundle 32 b extends along double arrow Px, and the spot or spots extend along a double arrow Py. [0036] [0036]FIG. 3 shows a further embodiment of detector element 43 . Detector element 43 comprises at least two linear sensors 48 and 49 arranged parallel to one another. Each of the linear sensors comprises a plurality of linearly arranged photodiodes 52 . [0037] [0037]FIG. 4 shows the laser autofocus system for microscope-based system 1 in the focused state. In this example, cylindrical lens 42 is omitted and detector element 43 is not tilted. Remitted measurement light beam bundle 32 b is, in this case, focused onto a single spot 50 determined by optical system 41 . [0038] [0038]FIG. 5 shows the result when cylindrical lens 42 is added. Remitted measurement light bundle 32 b is, in this case, focused onto a by optical system 41 and cylindrical lens 42 into a single sharp line 60 . Note in this context that the plane defined by detector element 43 is parallel to plane 44 spanned by the X and Y coordinate axes. Plane 44 corresponds to surface 21 of specimen 20 . [0039] [0039]FIG. 6 depicts the situation in which surface 21 of specimen 20 has a structure that displays a differing vertical profile (see FIGS. 7 a and 7 b ) As already depicted in FIG. 2, measurement sensor 43 is pivoted about the axis parallel to the X axis of the coordinate system. Plane 44 spanned by the X and Y coordinate axes is parallel to surface 21 of specimen 20 . In the present case, tilting of detector element 43 about the X axis yields several spots 70 , of which each individual spot represents a specific surface on specimen 20 . The capability thus exists for focusing onto multiple planes. [0040] [0040]FIGS. 7 a and 7 b depict two exemplary embodiments of the surface structure of a specimen 20 . FIG. 7 a depicts the situation in which one or more transparent films 61 are applied one above another onto surface 21 of specimen 20 . The autofocus system can focus simultaneously onto the different films. In the example shown in FIG. 7 b , a stepped structure 62 , which itself can in turn be applied on a transparent film 61 , is configured on surface 21 of specimen 20 . Stepped structure 62 is small compared to the measurement spot on specimen 20 . The result for the measurement spot is therefore on the one hand an optimum focus position on top surfaces 63 of stepped structure 62 , and on the other hand a further optimum focus position for trenches 64 of stepped structure 62 . Depending on the configuration of stepped structure 62 or the number of different films 61 , several optimum focus positions are obtained that can be sharply focused onto. In the plurality of focus positions, each of these focus positions or planes generates a spot 70 on detector element 43 . By analyzing the position of these spots 70 with respect to one another, it is possible to identify the various planes of the specimen and then bring the desired plane into focus. [0041] The invention has been described with reference to a particular exemplary embodiment. It is self-evident, however, that changes and modifications can be made without thereby leaving the range of protection of the claims below.

The autofocus module possesses, between the detector element ( 43 ) and the optical means, a cylindrical lens ( 42 ) that, for determination of the focus position, generates a line on the detector element ( 43 ). In addition, the detector element ( 43 ) is pivotable about an axis in such a way that it is inclined with respect to a plane defined by the surface of the specimen ( 20 ), and its inclination is adjustable. All the optical components of the autofocus module are combined in a housing ( 25 ) that can be quickly flange-mounted onto an existing microscope-based system ( 1 ).

RELATED APPLICATION [0001] This application is a continuation of U.S. application Ser. No. 12/906,375, filed Oct. 19, 2010 which claims priority to U.S. application Ser. No. 11/141,837, filed Jun. 1, 2005, which issued on Dec. 16, 2008 as U.S. Pat. No. 7,464,862, which claims priority to U.S. provisional application Ser. Nos. 60/579,997 filed Jun. 15, 2004 and 60/631,300, filed Nov. 24, 2004, which are relied on and incorporated herein by reference. COPYRIGHT NOTICE [0002] A portion of the disclosure of this patent document may contain material, which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. FIELD OF THE INVENTION [0003] The present invention relates to an apparatus and method for enhancing the functionality and security of point-of-sale terminals through the use of a portable non-volatile memory device using software and data carried within the device. BACKGROUND OF THE INVENTION [0004] In recent years, point-of-sale (POS) terminals and the software that supports POS business applications have become increasingly complex. New ‘modular’ applications have been developed to capitalize on the new POS terminal capabilities and serve to increase the utility value of the point-of-sale terminal. Concurrently, the internet has provided an opportunity to increase the communication bandwidth to the POS terminals, again increasing the type of functionality and transactions that can be supported. However, the POS terminals themselves lack the capacity to store large amounts of data and the business applications available to POS terminals are therefore limited. [0005] The number of merchants, terminals and transactions is increasing annually. Along with these increases, there has been an increase in fraud at the point-of-sale. Current methods fail to adequately prevent consumer and merchant fraud from occurring at the point-of-sale. Authenticating transactions originating from POS devices using secure tokens, digital certificates and other unique merchant identifiers used to control or limit individual user access and functionality are not easily supported by conventional methods. [0006] Also, the process of configuring the POS terminal to function in accordance with the merchant's needs and approved transactions is becoming increasingly complex and time consuming. One drawback to conventional methods for configuring POS devices is related to the current method of downloading the POS business application programs (eg. restaurant, retail, lodging, mail order, petroleum) and the merchant-specific configuration attributes (eg. Bar-tabs, tips, merchant-id, terminal-id, American Express SE number). Current methods rely on transferring (i.e. downloading) this information over dial or high-speed connections with a host-based system. The process is very time consuming, error prone and therefore expensive. [0007] Another drawback to conventional methods for introducing new products to the market is related to the fact that the POS business applications must first be certified by the credit card processors (such as Vital Processing, Nova Information Systems, Global Payments, RBS Lynk, First Data) in advance of commercial use. Certification must be completed separately by each processor for each type of POS terminal and business application prior to the device being approved for sale and support (as a ‘Class-A’ product). This certification process is generally manual in nature, time consuming and expensive and often requires 6 to 12 months per each business application. Any single change such as a line of source code (or for example an additional module added) to a business application requires that the certification process start over again. POS terminal manufacturers (i.e. Verifone, Hypercom, Ingenico, others) are therefore constrained in their ability to sell and distribute new POS terminal models until the business applications are certified (and therefore supported) by the major processors. This scenario creates friction in the distribution channel as the manufacturers seek to gain market share with new innovative equipment because it requires them to wait for each of the major processors (i.e. First Data, Vital Processing, Global Payments, Nova Information Systems, RBS Lynk, others) to first certify the business applications. [0008] Finally, because of the high cost of the device and the security requirements, the POS terminal industry is generally constrained to sell terminals and software only for use by approved merchants and they do not typically sell terminals directly to consumers for use at the home or office. [0009] The price of non-volatile (flash) memory is rapidly decreasing while the capacity and available is increasing. The next generation of POS devices will support non-volatile, detachable flash memory from serial, USB, and other methods. In fact, POS manufacturers are in the very beginning stages of supporting USB devices on POS terminals and there are no commercial uses of this technology today on POS devices. Computer programs (i.e. Business Applications) can and should be developed to enhance the utility value, functionality and security of these next generation POS devices. It will be difficult for the industry to embrace this new technology using current methods. [0010] Therefore, a need exists for an apparatus and method that addresses these shortcomings in the prior art by utilizing the new capabilities provided through non-volatile, removable flash memory. SUMMARY OF THE INVENTION [0011] The present invention answers these needs by providing an apparatus and method for configuring, altering, controlling, securing, and extending the processing capability and functionality of POS devices using a non-volatile memory device using software and data carried within the device. [0012] According to the present invention design, a portable housing is provided with non-volatile memory inside. An interface is provided on the housing for communication between the non-volatile memory and the Removable Flash Enabled POS Device. Business software applications and configuration data are loaded into the non-volatile memory. The software applications can be loaded into the non-volatile memory by the POS terminal manufacturer, the Independent Sales Organization (ISO), by a payment processing company, or by the Merchant via a CD-ROM, the Internet, or other suitable means. [0013] Because the software ‘business applications’ and configuration data ‘merchant specific attributes’ reside (either fully or partially) on the removable storage device (non-volatile memory) and not on fully on the POS terminal (current industry standard), the present invention may be used to configure and inter-operate with multiple POS devices. [0014] It is thus an advantage of the present invention to provide an apparatus and method for quickly configuring, enhancing, controlling, securing, or extending the functionality of a Removable Flash Enabled POS Device without time-consuming and expensive software modifications or host-based download processes. To this end, the present invention is highly portable, operates independently of any particular POS terminal, and is compatible with a wide variety of POS terminal devices. [0015] Embodiments of the present invention are described below by way of illustration. Other approaches to implementing the present invention and variations of the described embodiments may be constructed by a skilled practitioner and are considered within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1 is an overview of the primary components which would be required to support all of the invention embodiments. Components include: (1) Removable-Flash Enabled POS Device; (2) Removable Flash Memory; (3) Dial-up, Wireless, or High-speed internet connection to Host Processor; (4) Host Processor; (5) Cable; (6) File Server; (7) Personal Computer. [0017] FIG. 2 is an overview of the basic required components which would be required to support a limited set of the invention embodiments. Components include: (1) Removable Flash Enabled POS Device; (2) Removable Flash Memory. DETAILED DESCRIPTION OF THE INVENTION [0018] An embodiment of the invention allows for the secure storage of any persistent data (data of a permanent nature until changed or deleted) onto [ FIG. 1 : Removable Flash Memory]. This persistent data may be related to POS terminal configuration and, or transaction data. This data volume currently exceeds the storage capacity of the POS device [ FIG. 1 : Removable Flash Enabled POS Device] and therefore limits the utility value and overall functionality of the device to the merchant. [0019] An embodiment of the invention allows for the tracking of cardholder and related customer transaction activity on the [ FIG. 2 : Removable Flash Memory] for the purpose of gift and loyalty program tracking without the need for an online, host-based connection. [0020] An embodiment of the invention allows for the storage of known lost, stolen or fraudulent credit card and debit card numbers on the [ FIG. 2 : Removable Flash Memory], to prevent the use of these cards for POS transactions without the need for a host-based online connection (or in an offline mode). In connection with this embodiment, merchant-specific, employee-specific or location-specific fraud rules and limits may be defined and enforced without the need for an online connection to a host. [0021] An embodiment of the invention allows for the immediate configuration of a new or re-configuration of a POS terminal device shown in [FIG. 2 —Removable Flash Enabled POS Device] using data and programs stored on the [ FIG. 2 : Removable Flash Memory] without the need to dial, download or connect the POS terminal with a central, host-based configuration process. [0022] An embodiment of the invention allows for the storage of daily transaction totals on the [ FIG. 1 : Removable Flash Memory] for internal control, balancing, and reconcilement purposes using the [ FIG. 1 : PC or FIG. 1 : File Server]. [0023] An embodiment of the invention allows for the secure storage of daily transactions (or batches of transactions) on the [ FIG. 1 : Removable Flash Memory] for the subsequent submission or ‘uploading’ to a host-based authorization system [ FIG. 1 : Host] and, or a local PC-based reporting process as shown in [ FIG. 1 : Personal Computer] or [ FIG. 1 : File Server]. [0024] An embodiment of the invention allows for the creation of authorized users and passwords for the merchant-specific POS device and would therefore require the [ FIG. 1 : Removable Flash Memory] to be connected to the POS device [ FIG. 1 : Removable Flash Enabled POS Device] prior to use and during use. This embodiment will also serve to control the functionality of the device [ FIG. 1 : Removable Flash Enabled POS Device] for specific users and therefore act as a ‘key’ to this POS device. [0025] An embodiment of the invention allows for protection of files and data stored on the POS device [ FIG. 1 : Removable Flash Enabled POS Device] or the removable storage device [ FIG. 1 : Removable Flash Memory] through the use of an encryption method which is compliant with current payment industry security standards set by Visa (i.e. CISP), MasterCard, and American Express. [0026] An embodiment of the invention allows for the merchant-specific configuration of a POS device [ FIG. 1 : Removable Flash Enabled POS Device] to be backed up onto [ FIG. 1 : Removable Flash Memory] and restored onto another identical POS device. [0027] An embodiment of the invention allows for an independent audit or sampling of POS transactions from [ FIG. 1 : Removable Flash Enabled POS Device] onto [ FIG. 1 : Removable Flash Memory] for use by internal or external auditors as part of Sarbanes Oxley or related internal control requirements. [0028] An embodiment of the invention provides a mechanism for capturing signatures and receipts from the POS device [ FIG. 1 : Removable Flash Enabled POS Device] onto [ FIG. 1 : Removable Flash Memory] which can be later transferred to [ FIG. 1 : Personal Computer] or [ FIG. 1 : File Server] and used for customer service, charge-back research and other related value-add purposes. [0029] An embodiment of the invention provides a mechanism for capturing check images and check data from [ FIG. 1 : Removable Flash Enabled POS Device] and storing this information onto [ FIG. 1 : Removable Flash Memory] formatted in compliance with Check21 and, or NACHA's ARC requirements. This data can subsequently be transferred to [FIG. Personal Computer] or [ FIG. 1 : File Server] or [ FIG. 1 : Host] and used for financial transaction fulfillment, clearing other related purposes. [0030] An embodiment of the invention provides a mechanism for storing and retrieving HTML and similar presentation content on the [ FIG. 1 : Removable Flash Memory] as required to format screens on [ FIG. 1 : Removable Flash Enabled POS Device]. [0031] An embodiment of the invention provides a means to store onto the [ FIG. 1 : Removable Flash Memory] and display marketing presentations such as flash or video presentations on the screen of the POS device [ FIG. 1 : Removable Flash Enabled POS Device]. [0032] An embodiment of the invention provides a means to conduct customer surveys on [ FIG. 1 : Removable Flash Enabled POS Device] and collect and store survey results on [ FIG. 1 : Removable Flash Memory]. This data can subsequently be transferred to [ FIG. 1 : Personal Computer] or [ FIG. 1 : File Server] or [ FIG. 1 : Host] and used for customer service other related purposes. [0033] An embodiment of the invention provides a means of storing product catalogs, inventory levels and pricing on [ FIG. 1 : Removable Flash Memory] or [ FIG. 2 : Removable Flash Memory] to allow customers to shop at the POS terminal [ FIG. 2 : Removable Flash Enabled POS Device] while in an offline mode. This inventory data can subsequently be transferred to [ FIG. 1 : Personal Computer] or [ FIG. 1 : File Server] or [ FIG. 1 : Host] and used for updating central inventory, re-order and other related purposes. [0034] An embodiment of the invention allows for local “stand-in” processing using data, logic and rules contained within the [ FIG. 2 : Removable Flash Memory] to authorize transactions when the host is down in lieu of (or in addition to) traditional voice authorizations. In connection with this embodiment, the locally authorized transactions would be uploaded to the host [ FIG. 1 : Host Processor] automatically whenever the online connection is restored. [0035] An embodiment of the present invention provides a means of storing onto [ FIG. 1 : Removable Flash Memory] and dispensing coupons from [ FIG. 1 : Removable Flash Enabled POS Device] to customers in order to encourage repeat sales and to calculate discounts on sale items for qualifying customers. [0036] An embodiment of the invention allows for music and games to be stored on to [ FIG. 1 : Removable Flash Memory] and played through the POS device [ FIG. 1 : Removable Flash Enabled POS Device]. [0037] An embodiment of the invention allows for the configuration of a virtual private network (VPN) or similar secure network over the [ FIG. 1 : Dial-up, Wireless or High-speed Internet connection to Host] to facilitate authentication to the network's processor [ FIG. 1 : Host Processor]. This embodiment also supports other advanced security mechanisms which otherwise would not be supportable by the POS device. In connection with this embodiment, a secure token, digital certificate, encryption key or other unique identifier is permanently stored on the non-volatile memory device [ FIG. 1 : Removable Flash Memory] and released to the payment network to authenticate each session and, or transaction. [0038] An embodiment of the invention facilitates the transfer (such as downloading from the internet or a wireless network) of large files (such as but not limited to: inventory levels, pricing, negative card files, bin tables, music, games, marketing presentations, etc.) through the connection POS device [ FIG. 1 : Removable Flash Enabled POS Device] over high-speed connections [ FIG. 1 : Dial-up, Wireless, or High-speed internet connection to Host Processor] and stored directly onto [ FIG. 1 : Removable Flash Memory]. [0039] An embodiment of the current invention would allow the POS device to route payment or non-payment transactions based on bin tables (and related rules) that are stored on the removable device. In connection with this embodiment, these bin tables would be updated periodically thought a connection such as [ FIG. 1 : Dial-up, Wireless, or High-speed internet connection to Host Processor] or via CD ROM. [0040] An embodiment of the invention integrates a Personal Computer with a POS device for merchant or home users. Connectivity would be provided to the non-volatile flash memory [ FIG. 1 : Removable Flash Memory] to create an interoperable application that fully leverages the capabilities of the PC [ FIG. 1 : PC]. In connection with this embodiment, a merchant or consumer will be able to initiate a card-centric (swipe and signature for pin-based) financial transaction from their home or business using the [ FIG. 1 : Removable Flash Memory] and without the need for a separate POS device. This embodiment also creates a potentially huge new market for accepting secure payment transactions from millions of existing and future PCs. [0041] An embodiment of the invention would allow consumer credit card, pre-paid card, gift card, and other related personal account information to be securely stored on a consumer's personal non-volatile memory device (such as a USB flash memory device) [ FIG. 1 : Removable USB Flash Memory] and accessed by the POS terminal [ FIG. 1 : Removable Flash Enabled POS Device] when inserted into the POS terminal or via RFID. This embodiment would therefore replace the need for the consumer to provide a magnetic-stripe, smart-card or other card-centric payment device. [0042] Having thus described the invention in detail, it should be apparent that various modifications and changes may be made without departing from the spirit and scope of the present invention. Consequently, these and other modifications are contemplated to be within the spirit and scope of the following claims.

An apparatus and method for configuring, altering, controlling, securing, and extending the processing capability and functionality of PCs and POS devices using a non-volatile memory device using software and data carried within the apparatus.

[0001] This application is a continuation-in-part of co-pending application Ser. No. 09/907,585 filed Jul. 17, 2001 which in turn is a continuation of Ser. No. 09/103,290 filed on Jun. 23, 1998, now U.S. Pat. No. 6,263,092, which in turn is a continuation of Ser. No. 08/676,660, filed on Jul. 10, 1996, now U.S. Pat. No. 5,815,591. CROSS-REFERENCE TO RELATED APPLICATIONS [0002] Related applications are: [0003] “Method and System for the Display of Regions of Interest in Medical Images,” Ser. No. ______, filed Nov. 21, 2001, attorney docket number 8498-039-999; [0004] “Vessel Segmentation with Nodule Detection,” attorney docket number 8498-042-999, filed concurrently herewith; [0005] “Automated Registration of 3-D Medical Scans of Similar Anatomical Structures,” attorney docket number 8498-043-999, filed concurrently herewith; [0006] “Lung Field Segmentation From CT Thoracic Images,” attorney docket number 8498-044-999, filed concurrently herewith; [0007] “Pleural Nodule Detection from CT Thoracic Images,” attorney docket number 8498-045-999, filed concurrently herewith; and [0008] “Graphical User Interface for Display of Anatomical Information,” Ser. No. ______, filed Nov. 21, 2001, claiming priority from Serial No. 60/252,743, filed Nov. 22, 2000 and from Serial No. 60/314,582 filed Aug. 24, 2001. [0009] This application hereby incorporates by reference the entire disclosure, drawings and claims of each of the above-referenced applications as though fully set forth herein. FIELD OF THE INVENTION [0010] The present invention relates to the field of computer-aided detection of abnormal lesions and features in digital images. In particular, the invention relates to a fast algorithm for detecting possible anatomical abnormalities that may be overlooked in digital medical images. BACKGROUND OF THE INVENTION [0011] The diagnostically superior information available from data acquired from various imaging systems, especially that provided by multidetector CT (multiple slices acquired per single rotation of the gantry) where acquisition speed and volumetric resolution provide exquisite diagnostic value, enables the detection of potential disease problems at earlier and more treatable stages. Given the vast quantity of detailed data acquirable from imaging systems, various algorithms must be developed to efficiently and accurately process image data. With the aid of computers, advances in image processing are generally performed on digital or digitized images. [0012] Digital acquisition systems for creating digital images include digital X-ray film radiography, computed tomography (“CT”) imaging, magnetic resonance imaging (“MRI”) and nuclear medicine imaging techniques, such as positron emission tomography (“PET”) and single photon emission computed tomography (“SPECT”). Digital images can also be created from analog images by, for example, scanning analog images, such as typical x-rays, into a digitized form. Further information concerning digital acquisition systems is found in our above-referenced copending application “Graphical User Interface for Display of Anatomical Information”. [0013] Digital images are created from an array of numerical values representing a property (such as a grey scale value or magnetic field strength) associable with an anatomical location referenced by a particular array location. In 2-D digital images, or slice sections, the discrete array locations are termed pixels. Three-dimensional digital images can be constructed from stacked slice sections through various construction techniques known in the art. The 3-D images are made up of discrete volume elements, also referred to as voxels, composed of pixels from the 2-D images. The pixel or voxel properties can be processed to ascertain various properties about the anatomy of a patient associated with such pixels or voxels. [0014] Once in a digital or digitized format, various analytical approaches can be applied to process digital anatomical images and to detect, identify, display and highlight regions of interest (ROI). For example, digitized images can be processed through various techniques, such as segmentation. Segmentation generally involves separating irrelevant objects (for example, the background from the foreground) or extracting anatomical surfaces, structures, or regions of interest from images for the purposes of anatomical identification, diagnosis, evaluation, and volumetric measurements. Segmentation often involves classifying and processing, on a per-pixel basis, pixels of image data on the basis of one or more characteristics associable with a pixel value. For example, a pixel or voxel may be examined to determine whether it is a local maximum or minimum based on the intensities of adjacent pixels or voxels. [0015] Once anatomical regions and structures are constructed and evaluated by analyzing pixels and/or voxels, subsequent processing and analysis exploiting regional characteristics and features can be applied to relevant areas, thus improving both accuracy and efficiency of the imaging system. For example, the segmentation of an image into distinct anatomical regions and structures provides perspectives on the spatial relationships between such regions. Segmentation also serves as an essential first stage of other tasks such as visualization and registration for temporal and cross-patient comparisons. [0016] Key issues in digital image processing are speed and accuracy. For example, the size of a detectable tumor or nodule, such as a lung nodule, can be smaller than 2 mm in diameter. Moreover, depending on the particular case, a typical volume data set can include several hundred axial sections, making the total amount of data 200 Megabytes or more. Thus, due to the sheer size of such data sets and the desire to identify small artifacts, computational efficiency and accuracy is of high priority to satisfy the throughput requirements of any digital processing method or system. [0017] Accordingly, it is an object of the present invention to provide a fast, yet accurate, computer-assisted diagnosis (“CAD”) system for assisting in the identification of suspicious masses and tissue in digital images, the CAD system being capable of producing an output which directs attention to suspicious portions of digital images. It is an object of the invention to provide such systems and methods for processing digital images that can effectively and quickly identify regions of the image containing suspicious features requiring further consideration and evaluation. It is a further object of the invention to provide a system and method for detecting nodules. It is a further object of the invention to provide a nodule detection approach that can be adapted to perform on or compensate for partial volumes or data sets. It is a further object to provide a nodule detection process and system that is adaptable for a large range of anatomical regions for processing yet is fast enough to permit use of the CAD system in a clinical radiology environment. [0018] The foregoing and other problems are overcome by methods and apparatus in accordance with embodiments of this invention. SUMMARY OF THE INVENTION [0019] These and other objects of the present invention are provided for by an improved CAD system and method for rapidly detecting nodules and other suspicious features from digital images. A CAD system according the present invention employs a fast method for detecting suspicious regions from digital images, the method including steps for determining an array of potential intersections from a plurality of voxels using vector information. The vector information is obtained from a plurality of voxels to produce a cumulative multidimensional array. Using information derived from the cumulative array, such as the directions, positions and strengths of local maxima for identifying nodules and other suspicious matter, anatomical information associated with a digital image or volume can be derived. The approach effectively has several distinct stages. [0020] A first stage uses digital image processing techniques to quickly highlight regions requiring further and more detailed processing. The first stage operates with somewhat lower sensitivity than is possible with other more detailed analyses. In this way, computation resources can be more effectively applied to areas of concern. [0021] A second stage uses a detailed gradient distribution analysis that only operates on voxels identified by the first stage. Effectively, the second stage provides higher resolution analysis of the regions identified by the first stage. [0022] Since the first stage effectively and quickly identifies regions for further processing, the combination of the first stage analysis with the additional processing of second stage results in a fast yet effective overall algorithm to identify potential anatomical abnormalities from digital volumes. BRIEF DESCRIPTION OF THE FIGURES [0023] These and other objects and advantages of the present invention will be more readily apparent from the following detailed description of a preferred embodiment of the invention in which: [0024] [0024]FIG. 1 depicts an axial section of a CT digital image section; [0025] [0025]FIG. 2 is a conceptual diagram showing the determination of potential regions of intersection for two points in a line image in accordance with the present invention, the two lines not being associated with a common nodule; [0026] [0026]FIG. 3 shows a typical predetermined pattern P used to generate regions of potential intersection in the nodule detection algorithm according to the present invention; [0027] [0027]FIG. 4 is a conceptual diagram showing the determination of potential regions of intersection for two points in a line image in accordance with the present invention, the two lines being associated with a common nodule; [0028] [0028]FIG. 5 is a flowchart representing overall steps practiced by the system of the present invention; [0029] [0029]FIG. 6 is a process flow chart of one embodiment of the present invention; [0030] [0030]FIG. 7 is a flowchart representing a detection algorithm for the pixel-based information; [0031] [0031]FIG. 8 is a flowchart representing overall steps practiced by a system of the present invention; [0032] [0032]FIG. 9 is a representation of one approach using radial zones for output voxels; and [0033] [0033]FIG. 10 is a representation of a single pass calculation in a digital volume in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION [0034] The present invention provides for systems and methods capable of effective and accurate detection of suspicious features identified from 2-D and 3-D digital images. A 3-D digital volume can be generated from the 2-D slices by any one of various techniques known in the art. The terms “digital” and “digitized” as used herein will refer to images or volumes, as appropriate, in a digital or digitized format acquired via a digital acquisition system or via conversion from an analog image. [0035] The digital image sections and volumes to be processed, rendered, displayed or otherwise used include digitized images acquired through any plane, including, without limitation, saggital, coronal and axial (or horizontal, transverse) planes and including planes at various angles to the saggital, coronal or axial planes. While the disclosure may refer to a particular plane or section, such as an axial section or plane, it is to be understood that any reference to a particular plane is not necessarily intended to be limited to that particular plane, as the invention can apply to any plane or planar orientation acquired by any digital acquisition system. [0036] The present invention is preferably performed on a computer system, such as a Pentium™-class personal computer, running computer software that implements the algorithm of the present invention. The computer includes a processor, a memory and various input/output means. A series of CT axial or other digital images representative of an anatomical volume are input to the computer for processing by a detection algorithm. Examples of a digital image or section is shown in FIG. 1. [0037] The purpose of the detection algorithm is to quickly scan an input image volume generated from the digital images, highlight initial ROIs and process the ROI to detect, identify or otherwise provide detailed information regarding lesions, nodules or other suspicious anatomical features. Identified ROIs can be used, for example, to highlight regions for purposes of display, temporal comparison or for further processing. ROIs can also be used to segment the nodule in the original volume for further analysis. [0038] Various techniques are available for processing digital images to identify features and ultimately to identify ROIs. For example, various intermediate-level processes can be performed for line detection, circle detection, hole detection and corner detection (for various discussion and details regarding intermediate-level processing see, for example, E. R. Davies, Machine Vision: Theory, Algorithms, Practicalities, 2 nd Ed., Academic Press, 1997, pgs. 195-343, incorporated herein by reference). [0039] One such technique which is described in greater detail in copending application Ser. No. 09/907,585 and columns 9 through 12 of U.S. Pat. No. 6,263,092 is useful in processing structural information in digital images. In the '092 patent, this technique is used to detect speculated, or stellar-shaped, lesions in mammograms. Since a spiculation is a roughly symmetric set of lines radiating from a central point or region, the spiculations can be located by locating the lines and projecting the lines to their point of intersection. Such points of intersection are identified by use of a cumulative array. [0040] This process is illustrated in FIGS. 2, 3 and 4 which are reproduced from FIGS. 7, 8 and 9 of the '092 patent. The process begins by initializing a cumulative array C. The array has the same size and coordinate system as the digital image and the digital image, shown in FIG. 2 can be thought of as superimposed on the cumulative array. Following initialization, each pixel (i, j) in the digital image is considered in turn. If there is no line information in the pixel, the pixel is ignored. If, however, there is line information in the pixel, the cumulative array is incremented at certain locations defined by a predetermined pattern P centered at the projection of the pixel location (i, j) onto the cumulative array. After each pixel in the digital image is considered, the cumulative array C is completely formed. The array is then examined to locate those points having the highest values and these points are associated with the centers of spiculations. [0041] [0041]FIG. 2 is a conceptual diagram illustrating such processing of a 2-D digital image. Shown in FIG. 2 are two points (i1,j1) and (i2,j2) that lie somewhere along lines L1 and L2, respectively. The detection algorithm as applied to pixel-by-pixel analysis is based on the principle that any two lines L1 and L2 belonging to the same nodule or spiculation will have an entire series of points (i1,j1) and (i2,j2) whose tangents will overlap near a common point at the center of the spiculation or nodule. Regions of potential overlap for these two points, denoted P(i1,j1) and P(i2,j2), are shown superimposed over the line image for clarity. The regions of potential overlap P(i1,j1) and P(i2,j2) are simply rotated versions of a predetermined pattern P, shown in FIG. 3, which have been translated to be centered on the points (i1,j1) and (i2,j2), respectively. As shown in FIGS. 2 and 3, the predetermined pattern P is of a split rectangular or trapezoidal shape having a high aspect ratio (i.e., a large width to height ratio). For each point on a line, the cumulative array is incremented within the region of potential overlap as projected onto the cumulative array. [0042] As can be seen in FIG. 2, the region of potential overlap P(i1,j1) for the point (i1,j1) is roughly equivalent to a tangent of the line L1 containing the point (i1,j1), the tangent having been truncated at a distance corresponding to the length of the pattern P. Similarly, the region of potential overlays P (i2,j2) for the point (i2,j2) is roughly equivalent to a tangent of the L2 containing the point (i2,j2). In FIG. 2, the lines denoted L1 and L2 do not belong to a nodule or spiculation, and it can be seen that the regions of pattern overlap for various points (i1,j1) and (i2,j2) along lines L1 and L2 will be projected onto many locations in the cumulative array C. Thus, the cumulative array will be incremented relatively uniformly. [0043] In contrast, as shown in FIG. 4, lines L3, L4, L5, and L6, having pixels including exemplary pixels (i3,j3), (i4,j4), (i5,j5), and (i6,j6), respectively, belonging to the same spiculation or nodule will have repeated overlap of tangents near the center of the spiculation or nodule. [0044] Accordingly, if the regions of potential overlap, denoted generally as P(x,y), are accumulated into the cumulative array C, the cumulative array C will contain higher values at locations corresponding to regions of possible abnormality. The greater the number of intersecting, radiating lines at an abnormality, the greater the value of the cumulative array C. [0045] Importantly, this pixel-based detection algorithm is a “forward direction” algorithm in that each pixel in the line image is processed only once in generating the cumulative array C. Furthermore, a lookup table procedure may be used which directly maps the digital mammogram pixels (i,j) lying along lines and having direction values into regions of covered pixels in the cumulative array C, based on the shape of the predetermined pattern P. [0046] The lookup table procedure for mapping points and directions into regions of potential intersection may also incorporate weighting values in the predetermined pattern P. Thus, instead of simply adding a “1” to the cumulative array C for every array location falling inside the pattern P(i1,j1), a weighting value may be used. For example, points corresponding to a point P a in the predetermined pattern P of FIG. 4, lying directly along the center line of P, may be assigned a heavier weight than a point P b lying along the periphery of the predetermined pattern P. This is because peripheral points are less likely than center line points to lie directly at the center of the abnormality. [0047] The predetermined pattern P is designed in an empirical manner to maintain accuracy (minimizing false positives) while maximizing precision in finding abnormalities of the appropriate size. In one example, it may be desirable to detect abnormalities which have a radius of around 5 mm, because if the abnormalities grow to a size much larger than a 5 mm radius, it may be too late to stop the spread of the cancer. For a digital image in which 1 pixel corresponds to 200 microns, or in which 25 pixels equals 5 mm, it has been found that a predetermined pattern P having its opposing trapezoids extending from about 15 pixels to about 80 pixels from the center, with a width ranging from about 4 pixels near the center to 20 pixels at the periphery, yields satisfactory results. [0048] While the above discussion regarding FIGS. 2 - 4 has described detection of radiating lines in 2-D images, a similar analysis can be applied to detection of gradients in 3-D images. A similar procedure to the pixel-based process wherein an operation is performed on a pixel and the resulting information is effectively disbursed to adjacent pixels can be made to apply to voxels. [0049] Regions of potential overlap in 3-D may be translated to be centered on the points (x1, y1, z1) and (x2 ,y2, z2), respectively, the amount of rotation being a gradient or direction image value for voxel (x1, y1, z1) and for voxel (x2 ,y2, z2). [0050] The detection algorithm as applied to voxel-by-voxel analysis is based on the principle that any intensity regions belonging to the same nodule will have an entire series of points in 3-D whose gradient component will overlap near a common point at the center of the spiculation or nodule. [0051] Accordingly, if the regions of potential overlap, denoted generally as P(x, y, z), are accumulated into a cumulative array C′, the cumulative array C′ will contain higher values at locations corresponding to regions of possible abnormality. The greater the number of overlapping regions, or bins, at an abnormality, the greater the value of the cumulative array C′. [0052] In one embodiment of the present invention, an edge of the nodule is represented by vector that estimates characteristics of the nodule such as size, contrast, sharpness and shape. Vector information obtained from various voxels can be aggregated to provide further details and characteristics of a nodule. [0053] [0053]FIG. 5 shows the general steps performed by a CAD processing unit on digital images in accordance with the invention. At step 502 , images are either digitized or received in a digital format from a digital acquisition system. The digital images may be, for example, a 3000×4000 array of 12-bit gray scale pixel values. [0054] [0054]FIG. 5 shows the digital image being processed at step 504 by an overall nodule detection algorithm in accordance with the present invention. The overall nodule detection algorithm performed at step 504 includes a stage for generating or otherwise highlighting locations in the digital image or digital volume which may correspond to nodules, along with information, such as nodule intensity, for each location. Following step 504 , the digital image and list of nodule locations and information is output for display at step 506 . [0055] [0055]FIG. 6 shows in more detail the steps associated with the overall nodule detection algorithm of step 504 of FIG. 5. The nodule detection algorithm herein is based on generating local intensity gradient vectors from digital pixels for 2-D curves and from digital voxels for 3-D curves. A gradient vector is the rate of change of a function per unit distance in the direction of the vector and direction of the vector is the direction of maximum rate of change of the function at that location. Changes in tissue density in a region, which may be indicative of disease in the tissue of that region, affect intensity gradients associated with the voxels of a region's digital image. [0056] Gradient vectors taken at the edge of a nodule contain nodule orientation information. A plurality of edge gradient vectors can be processed to determine exact centers of the nodules. Intensity gradients and vector components of the intensity gradients are determined at step 602 . [0057] Deriving object features from gradients taken at boundaries of the objects can be performed by various transformation schemes for object detection. Different types of transformations are effective for detecting different features of an object. [0058] As applied to information derived from image slices, an array of gradient information is generated at step 602 , for each pixel (i,j) of an image slice. Pixel information is derived from vector gradients in a two-dimension space wherein directional information associated with the gradient taken at each pixel is projected onto pixels in a direction corresponding to the gradient. The process is similar to that described in connection with FIGS. 2 - 4 . First, a cumulative array is initialized. Each pixel is considered in turn. If there is no gradient information associated with the pixel, the pixel is ignored. If, however, there is gradient information associated with the pixel, the cumulative array is incremented at certain locations defined by a predetermined pattern P that is centered at the projection of the pixel location onto the cumulative array and oriented in the direction of the gradient. [0059] A similar process can occur for a voxel (x, y, z). Information derived from vector gradients taken in 3-D results in components in x-, y- and z-directions. Deriving gradients on a voxel-by-voxel basis at step 602 generates a multi-dimensional array containing directional information. Spherical information can be derived from vector gradients wherein directional information associated with edge gradients focus on a true center of a candidate nodule. [0060] When scanning a volume, it is not known where a possible nodule may be located. At step 604 , information of an intensity gradient calculation for a voxel is dispersed to nearby voxels through a classification procedure detailed below. The dispersed decomposition information is aggregated with information obtained from vector gradients associated with other voxels. The distribution of gradient information can then be processed to derive information relating to a volume corresponding the voxels. [0061] [0061]FIG. 7 shows a block diagram outlining steps for accomplishing the detection and prioritization, or classification, step 604 . The process is similar to that described in conjunction with FIGS. 2 - 4 . In 2-D, step 702 generates a cumulative array C from direction information corresponding to each pixel in the line image. The array has the same size and coordinate system as the digital image and the digital image can be thought of as superimposed on the cumulative array. The cumulative array C is first initialized. Then each pixel (i,j) in the digital image is considered. In particular, if a pixel (i,j) has no gradient information, it is ignored. However, if the pixel (i,j) has gradient information, the cumulative array C is incremented by a constant value at certain locations defined by a predetermined pattern centered at the projection of the pixel location (i,j) onto the cumulative array. After each pixel in the digital image is considered, the cumulative array C will be completely formed. [0062] The step 702 for generating a cumulative array C from direction information corresponding to each pixel in the line image can be extended to each voxel of a digital image volume. In such a case, the cumulative array C′ will have another dimension in its array to address the additional directional information and dispersion of gradient information in 3-D. Again, the cumulative array has the same size and coordinate system as the digital image so that each voxel in the digital image has a corresponding location in the cumulative array. The cumulative array is first initialized to remove, or otherwise compensate for, background noise levels. If a voxel (x, y, z) component has no intensity or density information to be dispersed or classified, it is ignored. However, if the voxel (x, y, z) has image information with a non-zero value, the cumulative array C′ aggregates such information for a particular volume. Specifically, array C′ is incremented by a constant value at certain locations defined by a predetermined pattern centered at the projection of the voxel location (x, y, z) into the cumulative array. After each voxel in the digital volume is considered, the cumulative array C′ will be completely formed. To illustrate, the values aggregated in an array location of C′ are based on intensity or density information derived from gradients for the predetermined pattern of a sphere centered at (x, y, z). [0063] [0063]FIG. 7 further shows a step 704 for prioritizing (or classifying) information contained in the cumulative array. In 2-D, the cumulative array C will contain values C(i,j) corresponding to the strength of possible abnormalities centered on the digital mammogram pixel located at coordinates (i,j). In 3-D, the cumulative array C′ will contain values C′ (x,y,z) corresponding to the strength of possible abnormalities centered on the digital voxel located at coordinates (x, y, z). [0064] The cumulative arrays C or C′ can contain local maxima associated with changes in tissue density and representative of potential abnormalities. The cumulative array C or C′, may be processed to identify locations and strengths of possible abnormalities in a digital image or volume. Patterns in a cumulative array can be processed to identify potential ROIs. [0065] One embodiment of the present invention in 3-D is algorithm 800 , illustrated in FIG. 8. Input volume data and images, I IN , are received at step 801 . Three-dimensional digital volume images can be constructed from stacked input slice sections. In one embodiment, digital volumes are created with flexible voxel sizes so that the thickness of the voxels vary. If the voxels are assumed to be isotropic in the X-Y plane then the voxel size in the Z direction is flexible and ranges from nearly isotropic for thin slices to thicker slices comprising many digital slices. [0066] A digital image volume may be subject to noise and interference from several sources including sensor noise, film-grain noise and channel errors. At step 805 , optional, but preferable, noise reduction and cleaning is performed on the image volume and image mask created at step 801 . Various statistical filtering techniques, including various known linear and non-linear noise-cleaning or processing techniques, can reduce noise effects. Step 805 also includes a smoothing operation that is applied to the whole image volume or partial image volume to reduce the graininess of the image and create a smooth image, S I . Various smoothing techniques are known in the art and are further described in co-pending applications referenced above, such as “Lung Field Segmentation From CT Thoracic Images” application. [0067] One effective 3-D smoothing filter for smoothing the input image is a 3-D Gaussian filter. For such a filter, the size of the Gaussian kernel used in the smoothing operation can be a tuning parameter. In one embodiment, the output (I SMOOTH ) is stored in a circular buffer in the scan direction and centered on the leading edge of the window of interest (WOI), discussed below (see FIG. 10), within which the gradient calculation is performed. [0068] Potential candidate nodules in volumetric digital images can be considered as local high-density lines around a mass. However, potential candidate nodules sometimes exhibit a very weak contrast and tend to be missed by simple thresholding techniques. Instead, and similar to the analysis described above, a gradient operation is performed on the voxel. At step 810 a 3-D gradient calculation is performed on the smoothed image, S I , to generate a gradient image, G I . [0069] In a preferred approach for step 810 , a gradient vector is calculated for each voxel in the input image in the x-, y- and z-directions. The smoothed image (S i ) and voxel dimensions (R x , R y , R z ) are used for this calculation: G x  ( x , y , z ) ≡    ( S x  ( x + 1 , y , z ) - S x  ( x - 1 , y , z ) ) / R x G y  ( x , y , z ) ≡    ( S x  ( x , y + 1 , z ) - S x  ( x , y - 1 , z ) ) / R y G z  ( x , y , z ) ≡    ( S x  ( x , y , z + 1 ) - S x  ( x , y , z - 1 ) ) / R z ( 1 ) [0070] For thick slice data where the voxel size in a dimension, e.g., the z-direction, is large, an interslice gradient can be calculated between slices. This makes the effective gradient image size in the z-direction (2*Depth−1) where Depth is the size of the original image in the z-direction for thick slice volumes. For thick slice volumes, the interslice gradient can be calculated as: G x ( x , y , z + 1 2 ≡    ( G x  ( x , y , z + 1 ) + G x  ( x , y , z ) ) / 2 G y ( x , y , z + 1 2 ≡    ( G y  ( x , y , z + 1 ) + G y  ( x , y , z ) ) / 2 G z ( x , y , z + 1 2 ≡    ( S x  ( x , y , z + 1 ) - S x  ( x , y , z ) ) / ( 0.5 × R z ) ( 2 ) [0071] At step 815 , the gradient vector, G I (equal to the sum of the vectors G x , G y , and G z ), obtained from the gradient calculation at 810 is input to a transform. [0072] Various mathematical operations can be performed to extract information from the gradient calculation 810 . For example, the Hough transformation allows a family of lines passing through a common point in the x-y-z domain to map into a connected set of points for a spherical pattern. As applied to spherical 3-D detection at step 815 , the Hough transform would be effective in the detection and analysis of spherical-related features (step 820 ). Hough transformations of the gradients may yield certain parametric curve features that, as applied to a volume can be effective in detecting globular-shaped nodules, 3-D spiculations and other rounded but connected masses. Alternatively, the processes detailed in conjunction with FIGS. 5 - 7 can be used to identify nodules. [0073] At step 815 , the transform operates on the gradients determined above to detect information related to a predetermined pattern. The gradient information from a voxel is effectively dispersed to nearby voxels through a classification procedure detailed below. [0074] At step 820 , the dispersed information obtained by a voxel from vector gradients of other voxels can be aggregated through various techniques. For example, the output region for the transform operation at step 815 can be divided into one or more radial zones. In one approach a transform output from a voxel will be assigned to a radial zones associated with the output on the basis, for example, of the magnitude of a value associated with the voxel. The information aggregated at step 820 can be processed to extract information regarding the likelihood of nodule detection at a voxel location (x, y, z). [0075] [0075]FIG. 9 depicts a sample output feature analysis and output classifiers embodiment corresponding to step 820 . A sample nodule 960 is shown having an input gradient 905 . The input gradient is associated with a voxel location (x, y, z) located on the edge of the 3-D nodule 960 . The gradient is generally a local maximum for those locations where there is likely to be a nodule edge. [0076] In FIG. 9, radial zones are shown with two radial lines 945 and 950 in a direction outward from the gradient location. [0077] The algorithm maintains two accumulations. One accumulation keeps a “probability of not directed” sum of the gradient voxels that point towards the output voxel and the other accumulation keeps the sum of the intensity of those gradient voxels. There are a plurality of radial zones 905 through 940 , the smallest zone 905 being closest to the voxel having the input gradient and the furthest zone 940 having the largest radius. The gradient direction determined above dictates the direction of the radial zones emanating from a voxel. Each radial zone, R, encompasses locations in a cumulative array C″, each of which has associated with it a value that is incremented whenever that location falls within a radial zone associated with one of the voxels. [0078] The lines are shown diverging away from gradient 905 . This divergence is based on the idea that intensity radiates outward from a location; and accordingly the radial zones are shown expanding in a direction away from the gradient 905 . Such a divergence, while not a requirement, provides for refinement in accumulating the effect of voxel gradients. An array associated with each voxel includes array dimensions for purposes of tracking and aggregating the total informational content associated with a particular location. H O, Count ({tilde over (R)})≡Sum of (1-P(r) of directed gradient voxel in Zone R  (3) H O, Sum ({tilde over (R)})≡Sum of Magnitudes of directed gradient voxel in Zone R  (4) [0079] where P(r) is based on the output region geometry (such as that of the Hough transform described above) and is a function of the distance (r) from the gradient voxel to the output voxel: P ( r  ) ~     Probability     of     a     random     gradient     being     directed     inward :     = Directed     Solid     Angle / ( 4  π     r 2 ) ( 5 ) [0080] where [0081] V Directed ({tilde over (R)}) Volume of directed output region for Zone R [0082] V Total ({tilde over (R)}) Volume of non-directed output region for Zone R [0083] From these accumulations, the count and average value of inward (or outward) facing gradient voxels can be calculated for each radial zone. [0084] For normalization purposes, a non-directional transform is also preferably performed. The non-directional transform can be important in the case where some of the gradient voxels surrounding an output voxel are not available (edge of volume) or are excluded (pre-segmentation excludes portions of the volume). In a transform of the present invention, a count is accumulated into all transformed output voxels in a sphere surrounding the gradient voxel. In this transform, there are two similar output accumulations for each radial zone. One output accumulation keeps a “probability of directed” sum of the gradient voxels and the other keeps the variance sum of the gradient voxels. [0085] H O, TotalCount ({tilde over (R)}) Sum of P(r) of gradient voxel in Zone R [0086] H O, VariancedSum ({tilde over (R)}) Sum of P(r)*(1−P(r)) of gradient voxel in Zone R [0087] From these accumulations, the number of inward directed gradients can be normalized by the expected number of inward (or outward) directed gradient voxels due to a random distribution of gradients and can be calculated for each radial zone. [0088] Once the cumulation into transformed output voxels is complete, features are calculated for each voxel at step 820 . In one approach, the expected counts of directed gradient voxels from a random distribution of gradients are initially calculated for each radial zone: H F , ExpectedCount  ( R ) ≡ H O , TotalCount  ( R ) × V Directed  ( R ) V Total  ( R ) ( 6 ) [0089] For each radial zone, the normalized counts (H F,NormalizedCount (R)) and the gradients (H F,Gradient (R)) are calculated: H F , NormalizedCount  ( R ) ≡    H O , Count  ( R ) - H O , TotalCount  ( R ) H O , VarianceCount  ( R ) H F , Gradient  ( R ) ≡    H O , Sum  ( R ) H O , Count  ( R ) ( 7 ) [0090] The shape of these functions is analyzed to estimate the size, contrast and sharpness of the detected nodule. [0091] Next, the range of radial zones (R min to R max ) that maximizes the following metric is found H F, Metric1 =H F, NormalizeCount ×H F, AverageGradient   (8) [0092] where H F, AverageNormalizedCount measures the number of directed gradients normalized by the number of directed gradients expected from a random distribution of gradients: H F , AverageNormalizedCount ≡ ∑ R = R min R max     H O , Count  ( R ) - ∑ R = R min R max     H F , ExpectedCount  ( R ) ∑ R = R min R max     H F , ExpectedCount  ( R ) ( 9 ) [0093] and H F,AverageNormalizedCount is the average gradient: H F , AverageGradient ≡ ∑ R = R min R max     H O , Sum  ( R ) ∑ R = R min R max     H O , Count  ( R ) ( 10 ) [0094] All of the above-described features can be input to a classifier that estimates the likelihood that a particular voxel is associated with the center of a nodule. [0095] At step 825 , the above-described features are input to a neural network classifier that estimates the likelihood that the voxel is at the center of a nodule (H L ). Step 830 indicates that only voxels that are above the threshold H thresh are processed further. [0096] Statistics about the distribution of outward facing gradients that surround a given voxel are calculated and processed at step 835 . From such statistics, features are calculated that characterize the size and shape of the distribution of gradients. A well-defined nodule will have an even distribution. The features can be used to differentiate various shapes, such as spherical shapes (nodule) or cylindrical shapes (vessel). In the case of a cylinder, size and direction estimations are calculated. In the case of a sphere, size and shape estimations are calculated. Geometric moment statistics can used to calculate distribution shape features. Such features include size, eccentricity and irregularity. [0097] In one approach, the vertices of a poly-tetrahedron are used to divide spherical direction into ‘N’ evenly spaced sectors. The distribution of gradients in the sectors that surround the output voxel are used to calculate features that characterize the completeness and shape of the distribution. [0098] At step 840 , the above-described features are input to a neural network classifier that estimates the likelihood that the voxel is at the center of a nodule (D L ). At step 845 , only voxels that are above the threshold D thresh will be processed further. [0099] At step 850 , voxels that pass the threshold D thresh are marked in the mask image with a scale value that is proportional the gradient distribution likelihood D L . [0100] For each voxel that exceed the threshold D thresh intensity, a voxel object structure, or array, is created to hold features and likelihood values. These objects are added to a voxel object list at step 855 . [0101] Thereafter, at step 860 regions of voxels with high likelihood are segmented, using known segmentation techniques, and collected into a list of ROIs. Features and likelihood from the segmented voxels are summarized and stored in ROI objects. [0102] To minimize memory usage and system requirements, various operations of the algorithm are preferably performed in one pass through the volume using buffers to hold intermediate results. Instead of performing computations in the entire 3-D image volume to be processed, a window of interest (WOI) is employed using voxels sandwiched between planes (see FIG. 10). A WOI starts at one end of the volume 1010 and move through the volume, for example, in a z-direction. Intermediate results are determined with respect to the WOI between planes 1020 and 1040 . Advantageously, a given voxel in the digital volume image is effectively considered with respect to only a part of the entire volume being processed (i.e., in the WOI) and results in a reduced computational burden. Thus, the method used in a process according to the present invention can be very fast and efficient. Moreover, the method is highly amenable to hardware implementation using parallel processors, thus increasing the speed of a CAD digital acquisition system even further. [0103] To assure adequate detection of nodules in a volume 1010 , the size of the WOI can be varied to be any size. For example, the WOI in FIG. 10 between planes 1020 and 1040 can be adjusted to have any thickness in the z-direction. [0104] In one approach, the thickness of the WOI is selected to be twice the maximum nodule radius (R MAX ). Optionally, a buffer memory can be used wherein only the results in the WOI are stored. If no abnormality is detected within a WOI, then the buffer can be reset over and over until a possible abnormality is identified. Potential nodule locations and nodule information can be stored, and the buffer initialized for the detection of additional abnormalities. [0105] There are two positions in the WOI where calculations are performed. The first position is the leading edge 1040 of the WOI where the Gaussian filter, gradient calculation and the transform are performed. The second position is at the center 1030 of the WOI where the accumulation is complete and surrounding gradient data is available. [0106] Like the pixel-based detection algorithm, the voxel-based detection algorithm is a “forward direction” algorithm. Each voxel in a WOI is processed only once in generating the cumulative array value. Furthermore, a lookup table procedure can be used which ultimately maps the output of a transform operation into radial zones of covered voxels in the cumulative array C″, based on the shape of the predetermined pattern. [0107] As with the 2-D case, the lookup table procedure for mapping points and directions into regions of potential intersection can incorporate weighting values in the predetermined pattern. Thus, instead of simply adding a “1” to the cumulative array C″ for every array location falling inside the pattern, a weighting value may be used. In one approach, the weighting value can be used to select an appropriate radial zone associated with a intensity gradient for a voxel. [0108] In this application, an efficient method for 3-D nodule detection from 3-D digital images is presented. The present invention provides a system and method that is accurate, efficient, flexible and detects pleural nodules that prior systems and approaches overlook or are incapable of detecting. The foregoing examples illustrate certain exemplary embodiments of the invention from which other obvious embodiments, variations, and modifications will be apparent to those skilled in the art. The invention should therefore not be limited to the particular embodiments discussed above, but rather is defined by the claims.

An algorithm is quickly scans a digital image volume to detect density nodules. A first stage is based on a transform to quickly highlight regions requiring further processing. The first stage operates with somewhat lower sensitivity than is possible with more detailed analyses, but operates to highlight regions for further analysis and processing. The transform dynamically adapts to various nodule sizes through the use of radial zones. A second stage uses a detailed gradient distribution analysis that only operates on voxels that pass a threshold of the first stage.