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: 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: 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 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.

Abstract: A phase locked phase conjugation system comprises a first (1) and a second (2) stimulated Brillouin scattering (SBS) cell. A laser beam is split into sub beams; one (9) is directed through the first SBS cell as a beam of collimated light and focused into the second SBS cell from which a phase conjugated beam is returned. One or more other sub beams (11, 12) are focused into the first SBS cell so that overlap occurs between focused sub beams and collimated beam. This provides a phase locked phase conjugated beam. Two or more sub beams are directed twice through laser amplifiers to provide an amplified phase locked phase conjugated beam. The second SBS cell may be a simple reflective cell operating on a focused laser sub beam, or may be an SBS loop arrangement having reflectors and lenses for causing optical feedback of the Brillouin scattered light.

Abstract: The invention provides a ferroelectric liquid crystal display with uniformly spaced greyscale levels. The invention uses a bistable ferroelectric liquid crystal display formed by a layer of chiral smectic liquid crystal material between two cell walls. The walls carry e.g. line and column electrodes to give an x,y matrix of addressable pixels, and are surface treated to provide bistable operation. Each pixel may be divided into subpixels thereby giving spatial weighting for greyscale. Temporal weighting of greyscale is obtained by switching a pixel to a dark state for time T1 and a light state for time T2. When T1 and T2 are not equal, four different greyscales are obtainable; i.e. dark, dark grey, light grey, and light. The present invention provides a required uniform spacing of greyscale levels by addressing each pixel two or more times in one frame time.

Abstract: A manufacturing method includes a process of once heating a liquid crystal material to a temperature at which an isotropic phase appears therein and then cooling the liquid crystal material, the liquid crystal material being a ferroelectric liquid crystal or antiferroelectric liquid crystal, to be performed under an applied AC electric field which generates an electroclinic effect in a temperature range of from a temperature 20.degree. C. above a phase transition temperature at which a transition in phase occurs from a smectic A phase to a chiral smectic C phase to a temperature 20.degree. C. below the phase transition temperature.

Abstract: In order to promote the formation of the C2 state during manufacturing of a ferroelectric liquid crystal display comprising a cell including a layer of chiral smectic ferroelectric liquid crystal material contained between two substrates. The manufacturing method includes the steps of (a) heating the liquid crystal material and (b) whilst allowing the liquid crystal material to cool from an elevated temperature, which is close to the phase transition temperature to the chiral smectic phase, allowing pressure to the liquid crystal material within the cell by means of rollers in such a manner as to produce mass flow of liquid crystal material within the cell so that the liquid crystal material preferentially adopts the C2 state on cooling to the device operating temperature. This avoids formation of both the C1 and C2 states in the manufactured display which would otherwise result in a patchy appearance, and allows faster switching at lower voltages.

Abstract: A passive rangefinder for determining the range to an object such as an aircraft, rocket or missile which emits electromagnetic radiation makes use of spectral measurements over a broad band of frequencies. The rangefinder includes means 202 for forming a real image of a field of view, spectrophotometer means 201 including an entrance aperture 27 placed to receive at least a part of said real image, dispersion means (15, 28, 29) for separating radiation of different wavelengths and detector means 24 for measuring the spectrum of radiation received from distinct portions of the entrance aperture. The detector output is connected to data processing means 204 arranged to deconvolve the received spectral profile with a stored representation (205) of a range-dependent atmospheric transmission spectral profile to obtain a representation of the spectral emission profile of radiation from the object.

Abstract: An ultrawideband transverse electromagnetic mode horn antenna for use at high voltages, comprises a pulse generator (1) and two transmission horns (12, 18) containing different dielectric media. The interface (30) between the dielectric media is configured so that a signal from the generator is incident on the interface at an angle substantially equal to the Brewster angle, thereby maintaining a good impedance match across the interface. A further advantage of the arrangement is that the TEM wavefront is preserved through the antenna section allowing operation at fast pulse risetime (less than 200 ps) for short duration (several ns) at high voltage.

Abstract: A long range artillery shell (1) comprising rocket propellant material (10), a rocket motor nozzle (14) and base bleed propellant material (12). Ignition of the rocket propellant material (10) is delayed until the base bleed propellant material (12) has substantially finished burning. The base bleed propellant material (12) may be housed in the same chamber and behind the rocket propellant material (10) in order to provide support to the rocket propellant material (10) during launch. The two propellant materials (10, 12) may be separated by a thermal ignition barrier (18) to prevent premature rocket ignition.