Abstract: A parallel processing system computer which utilizes the logic programming language Prolog comprising a plurality of processing nodes, each node comprising three central processing units (CPUs), a memory architecture adapted for Prolog execution and interfacing hardware, each processing node being connected to a communication bus and a real-time broadcast bus whereby the real-time data from an input can be broadcast via the real-time broadcast bus to each processing node. One of the CPUs is used to control the communications and scheduling of the node, the other two CPUs are used as sequential Prolog Processors (SPPS). Each node can be arranged such that the collection of unused memory is carried out by one SPP while another SPP continues to run Prolog program enabling continuous real-time operation. The memory architecture is hybrid and comprises local static RAM and global dynamic RAM. The dynamic RAM comprises a Prolog database of known signal for comparison with the real-time input signals.

Abstract: A ferroelectric liquid crystal display element is structured so that ferroelectric liquid crystal is provided between a plurality of signal line electrodes and a plurality of scanning line electrodes running perpendicular to one another, and includes a signal line electrode driving circuit made up of a gray-scale signal amplifying circuit and a gray-scale signal producing circuit, and a scanning line electrode driving circuit made up of a scanning signal amplifying circuit and a scanning signal producing circuit. The signal line electrode driving circuit applies to the signal line electrodes gray-scale signals including pulses which are phase modulated in accordance with a gray-scale level, and the scanning line electrode driving circuit selectively applies to the scanning line electrodes scanning signals including, in each scanning period, an erasure voltage, a selection voltage, and a non-selection voltage.

Abstract: An infrared optical system incorporates a lens for imaging a remote scene onto a detector within a cold shield. Stray radiation incident on the detector is reduced by an optical stop in the form of a light emitting diode producing negative luminescence. The LED emits less radiation than background, and contributes less to the detector photon noise than an optical stop not exhibiting negative luminescence.

Abstract: A multi-layer Auger suppressed diode having at least two exclusion interfaces and at least two extraction interfaces. A specific embodiment has two composite contacts, each consisting of a heavily doped layer (3, 4) and a buffer layer (8, 9) of lower doped, high bandgap material sandwiched between the heavily doped layer and the active region (2) of the device.

Abstract: This invention relates to metal oxides based films and a method for their production via a sol-gel route using metal bis(.beta.-diketonate) salts as precursors. They can be conveniently doped by Group (III), (IV) or (V) impurities and may be used to provide coductive coating on optically transparent substrates such as glass, ceramics or polymers.

Abstract: In order to the effects of impact on liquid crystal devices a polymer network is introduced into ferroelectric liquid crystal cells. A liquid crystal device comprises two spaced cell walls each bearing electrode structures and treated on at least one facing surface with an alignment layer, a layer of a smectic liquid crystal material enclosed between the cell walls, characterised in that the liquid crystal material contains a small amount of monomer. The liquid crystal material may also contain a photoinitiator. The monomer material may be cured to produce the polymer network; the curing may be carried out in the presence of an electric or magnetic field. Further, the monomer may be cured in an isotropic or liquid crystal phase.

Abstract: A liquid crystal display apparatus using a ferroelectric liquid crystal with negative dielectric anisotropy in which a blanking pulse having a width that is at least twice of a selecting period and a polarity opposite to a strobe pulse to be applied to a scanning electrode in the selecting period is applied to the scanning electrode before the selecting period during one frame period. Another liquid crystal display apparatus using a ferroelectric liquid crystal with negative dielectric anisotropy in which a strobe pulse is applied to a scanning electrode in a trailing part of the selecting period and a predetermined period that follows the selecting period. A blanking pulse of opposite polarity to the strobe pulse is applied to the scanning electrode before the selecting period in one frame period. A non-selecting period which is at least three times longer than the selecting period is provided between the blanking pulse and the selecting period.

Abstract: A method of tracking a system (1) having sensors (3) (e.g. gas turbine engines) by providing a computer model (4) which, from changes in sensor readings, can track (follow) changes in performance parameters of the system. These may be e.g. efficiencies of various of components such as compressors and turbines. In the common embodiment, the method used (Singular Value Decomposition) is a way of computing the most likely solution when there are more performance parameters than the number of sensors used and thus a degree of redundancy. The method allows system diagnosis and most importantly a tracked model allows the selection of a tailored control regime (9) which results in optimum efficiency for the individual system (engine).

Abstract: A compound of formula I ##STR1## wherein n=3-30; X and Y are independently chosen from C.sub.1-6 alkyl, phenyl or formula II:(CH.sub.2).sub.p O--M IIwherein p=1-20 and M is a group of formula III: ##STR2## wherein a, b and g are independently chosen from 0 and 1; G is selected from CO.sub.2, OCO and is a single bond when g=0; j=0-4; F indicates that one or more of the phenyl rings may be laterally fluorinated; Z is chosen from R, OR, CO.sub.2 R, OCOR or CN wherein R is selected from chiral C.sub.4-20 branched chain alkyl, provided that at least one of X and Y is selected from formula II and that the positions of X and Y relative to each other provide stereo-isomers.

Abstract: A ferroelectric liquid crystal display comprises a matrix of pixels addressable by first and second sets of electrode tracks crossing one another at the locations of the pixels. The pixels ale addressed by applying data pulses to the first set of electrode tracks and strobe pulses to the second set of electrode tracks to switch certain pixels selected by the data pulses from a first state to a second state under the effect of the voltage difference between the data pulses and the strobe pulses, and blanking pulses are applied to the second set of electrode tracks to set the pixels to the first state in advance of the application of subsequent strobe pulses to switch selected pixels from the first state to the second state.

Abstract: A circuit module for a phased array radar (10) incorporates radar frequency (RF) mixers (54a, 54b) connected to an RF splitter/combiner (52) and to in-phase and quadrature RF reference signals. The RF mixers (54a, 54b) are also connected to intermediate frequency (IF) processing circuitry (60 to 68) providing for phase control of RF signals and IF reference signals. In transmission mode, the RF mixer (54a, 54b) receive phase-controlled, digitally synthesised IF signals from clock-activated generators (68a, 68b). Their outputs are combined at the RF splitter/combiner (52) to provide single sideband upconversion of the phase-controlled IF signals. In reception mode, the RF splitter/combiner (52) and the RF mixers (54a, 54b) act as an image rejection mixer circuit in which the phase-controlled IF signals are local oscillator signals.

Abstract: A material of general formula I: ##STR1## where E=0 indicates a non-cyclic system, and E=1 indicates a cyclic system;G is R.sub.3 SiR.sub.1 R.sub.2 (O).sub.kR.sub.1, R.sub.2, R.sub.3 are independently selected from C.sub.1-16 alkyl which may be partly or fully halogenated, H and formula IA: ##STR2## wherein Y is a propylene group which may be partially halogenated with fluorine or chlorine and Y.sub.1 is independently selected from COO, OCO, O, S, CHOH, CHF, CO or CH.sub.2 ;Q and Q.sub.1 are independently selected from (CH.sub.2).sub.n wherein one or more non-adjacent methylenes may be replaced by O andn=0-20;Z and Z.sub.1 are independently selected from O, S, single covalent bond, COO or OCO; ##STR3## represents a mesogenic group and is given by the general structure II ##STR4## A, B, D are selected from the following rings: ##STR5## the above rings may be substituted with one or more of the following substituents in at least one of the available substitution positions: F, Cl, Br, CH.sub.

Abstract: A liquid crystal array device comprises a liquid crystal material contained between two substrates, a first and a second plurality of electrodes defining a plurality of pixels and driving circuitry for applying a first signal (Strobe Voltage) in succession to the first plurality of electrodes and for applying a plurality of second signals (Data Voltage) to each of the second plurality of electrodes. Each second signal comprises one of at least a first waveform and a second waveform and the first waveform and the second waveform each comprise first and second signal levels. The first waveform and the second waveform further comprise at least one portion at a third signal level different from the first and second signal levels. This provides a limited difference in heating effect upon the array between a signal comprising a plurality of first waveforms and an alternating succession of first and second waveforms.

Abstract: Apparatus which allows selection and generation of a variety of hologrammatic optical wavefronts. A device, which comprises a substrate layer of varying thickness and an electro optic layer, with a voltage dependent refractive index mismatch between the two, is used to modulate transmitted light, thus generating a hologrammatic wavefront. Said modulation can be changed by variation of an applied voltage and this changes the wavefront which is generated. The range of wavefronts which can be generated is defined by the distribution of substrate layer thicknesses across the device.

Abstract: A means and method of controlling the muzzle velocity of a gun launched projectile to ensure that the muzzle velocities of several rounds of the same type tend towards the same value or that of an individual round approaches some nominal value. A sensor means measures a parameter related to the muzzle velocity of a projectile and a control means instructs an electrothermal energy unit to discharge a fixed amount of energy into the gun barrel after a certain time delay, the time delay being derived from the measured parameter and being such to ensure that discharge causes the projectile to achieve a controlled muzzle velocity.

Abstract: Compounds of formula ##STR1## are provided which may be used in a variety of devices including liquid crystal devices, piezoelectric devices, pyroelectric devices and in optical recording media, where m=at least 5; and R.sub.x, R.sub.y and R.sub.z are independently from formula (IA), ##STR2## where Y is selected from COO, OCO, O, S, CHOH, CHF, CH.sub.2 ; Q=(CH.sub.2).sub.n wherein one or more non-adjacent methylenes may be replaced by O and n=1-20; Z is selected from O, S, a single covalent bond, COO, a OCO; when Y is CH.sub.2 then n may also be 0; formula (IB) is ##STR3## and represents any mesogenic group; and R.sub.x, R.sub.y and R.sub.z are also independently selected from H, OH, OCOR.sup.1, COOH, CO.sub.2 R.sup.1 (CH.sub.2).sub.p OH, (CH.sub.2).sub.p CO.sub.2 H, --(CH.sub.2).sub.p OR.sup.1 or --(CH.sub.2).sub.p CO.sub.2 R.sup.1 and p=1-20, R.sup.1 =H or C.sub.1-16 alkyl, when R.sup.1 =C.sub.2-16 alkyl the terminal CH.sub.3 group may be replaced by Br or Cl; provided that at least one of and R.sub.x, R.

Abstract: A cryptographic receiver (10) includes photon detectors (52, 54, 56, 58) arranged to detect photons arriving from filters (22) and (24). A fiber coupler (14) randomly distributes each received photon (16) from an optical fiber toone of two photon channels (18, 20). The filters (22, 24) are each unbalanced Mach-Zehner interferometers with a phase modulator (34, 44) in one arm (28, 38). The filters (22, 24) impose non-orthogonal measurement bases on photons within the respective channels (18, 20). A signal processor (60) derives a cryptographic key-code by analysis of signals received from the photon detectors (52, 54, 46, 58).

Abstract: A method of determining the location of an unknown source (10) transmitting an unknown signal to satellite relays (14 and 16) comprises receiving the signal from the relays at respective receivers (18). The receivers (18) receive reference signals via respective relays from a common source (22). The unknown signal and reference signal received by each receiver (18) are processed coherently to preserve their timing and phase information relative to one another independently of signals received elsewhere. The signals are frequency downconverted and digitised, and transferred to a common processing computer (150). The computer (150) performs cross ambiguity function processing of the reference signals to determine their relative Differential Time Offset (DTO) and Differential Frequency Offset (DFO).

Abstract: A liquid crystal device is provided with a pair of substrates (12, 16) containing a liquid crystal material (22). A wall structure comprising, for example, a plurality of walls (14) is provided between the two substrates. The wall structure provides mechanical strength to the device and resistance to flow of liquid crystal material which can cause deterioration in the device performance. The walls may extend in two mutually different directions (FIG. 8, 40) to provide mechanical strength and resistance to flow in two directions while the device can still be readily filled. The device is particularly applicable to a ferroelectric liquid crystal device.

Abstract: An infrared emitting pyrotechnic material comprising a fibrous carbon containing substrate (1) onto one or both faces (4, 5) of which is vapor deposited a combustible material layer (2, 3) which may be protected by an additional coating (6, 7). The thickness and composition of each of the layers (2, 3) are selected such that in use each of the layers is capable of igniting substantially simultaneously the entire surface on which it is deposited.