Abstract: An electronic circuit for Euclidean distance determination includes two floating gate transistors (M1, M2) connected in parallel. Voltages representing a reference point and its complement are applied to input lines (22, 24) and corresponding charges become stored on the transistors' floating gates (F1, F2). Voltages representing a data point and its complement are input to control gates (G1, G2). The transistors (M1, M2) produce a combined output current which is a quadratic or exponential function of the distance between the data and reference points according to whether the transistors are above or below threshold. The circuit (10 ) includes a diode-connected load device (M3) for deriving the square root of the output current, which is proportional to Euclidean distance when the transistors are operated above threshold. Refresh means (M44, M45) may be provided for resetting reference points. An array of circuits of the invention is employed for determination of distances between vector quantities.

Abstract: Methods for loading and alignment of liquid crystal polymers in electro-optic and electro-active devices comprise in-situ polymerisation between substrates of monomer material in the presence of a cationic initiator. This allows for the synthesis of liquid crystal polymers containing polyether backbones.

Abstract: An acoustic generating system is described incorporating a bubble generator (1) for forming pressurised gas bubbles and directing the bubbles in a plume from an outlet (7), and a low frequency sound source (2) to apply a varying pressure to the base of the plume of bubbles to modulate (8) the plume of bubbles, whereby a source of low frequency sound waves is produced. A method for generating and transmitting a low frequency acoustic wave using is also described.

Abstract: An addressable matrix display comprises an addressable matrix of pixels, a first set of electrode tracks on one side of the matrix and a second set of electrode tracks on the other side of the matrix. The sets of electrode tracks cross one another at the locations of the pixels, and the pixels are switchable by the application of respective switching waveforms to the electrode tracks. Furthermore at least one of the electrode tracks has a resistance which varies along the length of the electrode track in order to provide increased temperature uniformity over the display due to power dissipation during switching by the switching waveforms applied to the electrode tracks. More particularly the resistance in an intermediate section of the electrode track is greater than the resistance in two end sections of the electrode track.

Abstract: In a ferroelectric liquid crystal element, in order to excite a reverse electric field within the element in response to a waveform of a non-rewriting voltage, properties of the ferroelectric liquid crystal material, an element structure, driving waveforms, or other factors are adjusted so that molecules of the ferroelectric liquid crystal are allowed to switch between bistable states in response to a waveform of a rewriting voltage, while the ferroelectric liquid crystal exerts an anti-memory phenomenon in response to a waveform of a non-rewriting voltage.

Abstract: Semiconductor devices are prepared by growth of epitaxial layers on a substrate from metalorganic compounds of the formula MR.sub.3, R being an alkyl group, or its amine adduct. The metalorganic compound was prepared by reacting a Grignard reagent with a metal halide in an amine solvent.

Abstract: Liquid crystal polymer materials used in liquid crystal devices, piezoelectric devices, pyroelectric devices and recording media are described.

Abstract: A matrix-type display apparatus which permits a gradation display of gradation number R (R is an integer of not less than 2) includes m scanning electrodes and scans the m scanning electrodes n times in one frame period. The matrix-type display apparatus performs a time-division gradation display under such condition that a time ratio of display periods of the 1st, the 2nd, . . . , the nth display periods is exactly X:RX: . . . R.sup.n-1 X (X.gtoreq.0). To enable such display, the matrix-type display apparatus is driven based on the below-defined R and n, and X determined based on R and n. R and n satisfy ROT.sub.n (X).noteq.ROT.sub.n ((1+R)X), . . . ROT.sub.n (X).noteq.ROT.sub.n ((1+R+. . .+R.sup.n-2)X, ROT.sub.n ((1+R+. . . +R.sup.n-2)X).noteq.ROT.sub.n ((1+R+. . .+R.sup.n-1)X)=0, wherein ROT.sub.n (a) is a remainder when dividing a (a is 0 or a positive integer) by n is (for example, R=4, n=3). X satisfies (1+R+. . .+R.sup.n-1)X=n(m+b) (b.gtoreq.0) (for example, X=1).

Abstract: The drive circuit for a matrix-type display apparatus is a scanning driver for selecting one scanning electrode respectively for four selection periods, and displaying data of each bit for four bits in a pixel on the selected electrode. The scanning driver has four shift registers corresponding to four selection periods. To these shift registers, a clock having the width of four selection periods and a bit data indicating each bit are inputted. By the AND circuit, etc., a logical product of 15 shift signals from the shift register and four select signals is obtained, and using a signal of sum (logical OR) of the logical product, the ON/OFF of a selection voltage output switch and a non-selection voltage output switch is controlled. As a result, a drive circuit suited for the multiplex driving method can be achieved.

Abstract: A treatment process for a composite comprising a matrix of a precipitation hardenable aluminum alloy and a particulate or short fiber ceramic reinforcement. The process includes hot and/or cold working the composite, subjecting the composite to a controlled heating step in which the composite is raised from ambient temperature to a temperature of from 250 to 450.degree. C. at a rate of temperature increase less than 1000.degree. C. per hour, and subjecting the resulting heat treated composite to a solution treating step.

Abstract: A ferro-electric liquid crystal cell is addressed by row and column electrodes forming an x,y matrix of display elements. A strobe waveform is applied to each row in sequence while appropriate data waveforms are applied to all the column electrodes. At each display element the material receives an addressing waveform to switch it to one of its two switched states depending upon the polarity of the addressing waveform. The switching characteristics of ferro-electric materials depend upon the shape of the addressing waveform. Two different shapes of addressing waveforms are used to produce two different and separated switching characteristics (FIG. 3). Al least one switching characteristic curve may exhibit a minimum response time at one voltage value, and the display is operated at voltages above this. The data waveforms are alternating positive and negative pulses of period 2ts. The strobe waveform has a zero for one time period ts followed by a unipolar voltage pulse of duration greater than ts, e.g. 1.

Abstract: A method for the loading and alignment of liquid crystal polymers in electro-optic and electro-active devices by in-situ polymerization between substrates of liquid crystal monomers. The molecular weight of the resulting liquid crystal polymer is controlled by the addition of a chain transfer reagent, for example, a thiol-containing compound which may be a liquid crystal material.

Abstract: A process for the preparation of a fiber reinforced metal matrix composite comprising fibers embedded in a metal in which the process comprises forming a body with a layer of aligned fibers between at least two layers of metal foil and densifying said layers wherein the layer of aligned fibers comprises metal particles interposed between individual fibers, the metal particles being compatible with the metal foil. A preform for a fiber reinforced metal matrix composite is also claimed which comprises a resin and a layer of aligned fibers, the layer having metal particles interposed between adjacent fibers and the layer and particles being bonded together with the resin.

Abstract: A laminated composite material having patterned conductors integral to its structure made of several cloth layers and a penetrating resin matrix material in which at least one of the cloth layers has a deposited patterned layer of electrical conductor to form a conducting path in the resultant composite material. The electrical conductor is preferably deposited to such a thickness that individual fibers of the cloth are coated but that the resin permeates between individual fibers in the conducting regions. The conducting regions provide for external connection of embedded electronic devices.

Abstract: A method of aligning liquid crystal material by bringing into contact with a thin layer of polymer which contains the anthracenyl group, the polymer having previously been treated with plane polarised ultraviolet light. A liquid crystal cell is described wherein each of the substrates defining two opposing cell walls are coated on their inner surface with a suitable polymer for carrying out the invention. A typical embodiment of the invention would have repeat unit (II).

Abstract: An enzyme capable of catalyzing the removal of nitrite from pentaerythritol tetranitrate (PETN) is provided. The enzyme (known as PETN reductase enzyme) is produced by culturing a novel strain of the Enterobacter cloacae bacterium isolated from nature. The strain designated PB2 has been deposited as NCIMB 40718. The amino acid sequence of the enzyme and the genetic sequence which encodes for this enzyme have also been determined. A PETN reductase enzyme encoded by the on gene is provided. A method for producing PETN reductase enzyme in large quantities and methods of bioremediation using the enzyme so produced are also provided. Additionally there is provided a method of detecting the presence of PETN in a sample together with a biosensor for use in such a method.

Abstract: Apparatus for the position sensing of a remote target. A preferred embodiment is used to control the position of a graphical pointer on a computer screen. A light emitting diode illuminates the head of the computer operator and an array of detectors detect radiation returned by a retroreflector attached to the head of the operator. Signal processing means is included to derive information about the position of the operator's head from the detector outputs and convert it to a form suitable for input to computer.

Abstract: A method and device to measure parameters of temperature and gas composition in high temperature fluids which has particular application to compressible unsteady flowing fluid and rapidly changing temperatures of high temperature gases. The device comprises at least two temperature sensing elements, means for pre-setting said elements to different temperatures, and means for determining a parameter of the fluid from temperature readings of said sensing elements taken at least two time instants. The invention also provides a method of measuring fluid temperature by determining differing heat transfer rates from the temperature history of temperature sensors initially set to different temperatures before exposure to the fluid. Based on the same methodology and device, gas composition of binary flows can also be determined.

Abstract: A metal matrix composite material made of a fiber reinforcement having a coating of gadolinium and gadolinium boride, preferably as discrete layers, each having a thickness of 1 to 6 microns. This composite is made by coating reinforcing fibers with gadolinium using a deposition technique, further coating the fibers with gadolinium boride by a deposition technique and then consolidating the coated fibers into a metal matrix to form the metal matrix composite.

Abstract: A liquid crystal display cell comprises two cell walls spaced apart to enclose a layer of liquid crystal material. The cell walls carry electrode structures, e.g. arranged in rows and columns to give an x, y matrix of addressable elements or pixels. The liquid crystal material is aligned by a grating (grooved) structure on one or both cell walls. This grating structure is a bigrating with one symmetrical grating and an asymmetric grating which may be orthogonal to the symmetric grating. The grooves of the asymmetric grating varying their depth or asymmetry along the lengths to give a locally varying pretilt whose longer range average provides a pretilt in a preferred range, e.g. about 2-24 degrees.