Abstract: It is a problem extracting the photosignal component from detector output, to the exclusion of pedestal bias response. To overcome this, a time varying bias signal is applied to each element of the detector. The duration of the time varying bias signal, or if a periodic signal, the signal period, is chosen as long compared to photocarrier lifetime and the signal amplitude is large enough to range over a non-linear portion of the responsivity characteristic of each element. The bias signal contains a d.c. component so that the bias signal ranges about a point of operation--a point of asymmetry lying on the responsivity characteristic. The photosignal component of the output signal may be removed by time averaging or by harmonic separation. Alternatively the bias signal may be modulated, and the photosignal component extracted by detection of demodulated signal.

Abstract: An integrated circuit comprises a substrate having a plurality of components electrically isolated by regions of amorphous material formed by laser irradiation. Typically the laser radiation has a wavelength less than 400 nm a pulse length between 0.1 and 10 .mu.sec, and a power density between 0.1 and 0.8 J/cm.sup.2. The substrate material may be Si, Ge, GaAs, GaAlAs, InAs, InP, InAlP.

Abstract: A folding bridge is provided with flush top and bottom chords when opened through 180.degree. by a hinge comprising two hinge blocks pivotally interconnected by a swinging link, the rotation of each block relative to the link being limited to 90.degree. by a stop mechanism and being sequenced by a restraining mechanism. In specific application to a bridge, the restraining mechanism is gravity urged.

Abstract: Storage apparatus for combustible or explosive material, the apparatus comprising a substantially closed, heat-resistant container, an opening in a wall of the container to enable flow of quenching fluid into the container from an external supply of said quenching fluid, a valve which normally prevents flow of said quenching fluid into the container through the opening and detector means responsive to penetration of a wall of the container by a projectile or fragment and which, in the event of such penetration occurring, opens the valve to enable said quenching fluid to flow into the container through the opening, thereby controlling or preventing fire or explosion.

Abstract: An actuator output member (11) is angularly deflectable by two opposed, tangentially movable, pressure transmitting members (7, 8), each responsive to the pressure drop developed across two respective flow restrictors (1, 2) serially connected in a fluid circuit. Deflection is achieved by variation of one or both of the flow restrictors. In a fast response arrangement the fluid is electroviscous and the flow restrictors electrically variable.

Abstract: A method is described for the production of composite materials from layers of wood veneer and fibres bonded together and impregnated with resin. The method includes the steps of (a) impregnating at least one layer of reinforcement fibres with a first resin, (b) coating surfaces of at least one layer of wood veneer with a second resin, (c) stacking the at least one resin impregnated reinforcement fibre layer with the at least one layer of resin coated wood veneer and (d) bonding the layers together under conditions of pressure and temperature appropriate to the resins employed in step (a) and step (b) to produce a laminate. Examples of composites are given using carbon fibres and hard wood veneers together with properties thereof.

Abstract: An alloy having the nominal composition Ni--30/40 wt % Cr--1/5 wt % Ti--2/8 wt % Al is used for coating gas turbine components to give protection against oxidation--and sulphidation--corrosion. A specific alloy having the composition Ni--37 Cr--3 Ti--2Al is applied to a blade fabricated from a nickel superalloy by sputter ion plating to give an overlay coating up to 100 .mu.m thick. Preferably a platinum intermediate layer is flashed on to the substrate before coating. The coating alloy can additionally include rare earths, hafnium or silicon.

Abstract: A direct current electroluminescent device having a phosphor layer and coating electrodes, at least one of which is translucent, which has interposed between the phosphor layer and at least one of said electrodes a thin non-planar layer of an electrically non-conducting substance. The non-planar layer may have a cross section of undulating outline or may be a discontinuous layer, e.g. in the form of closely spaced dots. Preferably the non-planar layer is translucent and is arranged between the phosphor layer and a translucent electrode. Suitable materials for the non-planar layer include silicon monoxide, silicon dioxide, germanium dioxide, magnesium fluoride, cadmium fluoride, yttrium fluoride, yttrium oxide, zinc sulphide, copper sulphide.

Abstract: The arrangement is for cancelling unwanted sidelobes in travelling-wave arrays, especially the back lobe where the main beam approaches the end-fire direction; the array should have high symmetry, i.e., with the usual form of array (radiators spaced along a single feeder), the radiation patterns when fed from either end should be mirror images. Cancellation is obtained by having feed connections (2,2') at both ends of this form of array (1), the feed at one end being attenuated (8) relative to the other and effectively subtracted (6) therefrom. In RF form, for receiving or transmitting, the subtraction can be effected by phase-reversing (7) the signal in one of the feed connections. In baseband form, suitable for receiving only, diodes are included in both feed connections and subtraction performed at baseband frequency.

Abstract: A touch sensitive switch with a liquid crystal cell and a circuit for measuring capacitive changes when the cell is deformed by touch. The cell has a layer of a liquid crystal material between slides bearing electrodes. Capacitive changes are detected for example by a comparator or by a bridge circuit which includes one or more cells. Touching one cell unbalances the bridge. The area of cell that is touched may be coincident with or separate from a display area. For some types of cells extra sensitivity is achieved by maintaining a voltage across the cell between a critical and saturation value.

Abstract: A polar co-ordinate display of full 360.degree. arc comprised of electrode bearing substrates each side of a layer of dyed phase change liquid crystal material. One set of electrodes comprises concentric spirals, the other set comprises radials. The display is multiplex addressed using four select waveform signals. These four signals V.sub.1, V.sub.2, V.sub.3, and V.sub.x satisfy the following conditions:RMS(V.sub.x -V.sub.i)=V.sub.p, i=1, 2 or 3;RMS(V.sub.1 -V.sub.2)=V.sub.p ; RMS(V.sub.1 -V.sub.3)=V.sub.0where V.sub.p is an upper threshold voltage, and V.sub.0 a saturation voltage for dyed phase change hysteresis, and may be of the coded form;V.sub.1 =,1010,;V.sub.2 =,1100,;V.sub.3 =,0101,;V.sub.x =,0110,.These may be generated using two 2-bit registers with exclusive OR-gate feedback.

Abstract: A liquid crystal display comprises a layer of cholesteric or smectic liquid crystal material contained between a front and rear wall. A pen having a tip is caused to move across the front wall causing an observable change in the liquid crystal under the pen tip. The change in liquid crystal material may be between its grandjean or planar state and focal conic state. This change may be caused by local pen tip pressure, heat, light or electric field. Erasure of observed information is by flexing of the liquid crystal layer. Alternatively heating and cooling, or an electric field may be used to erase the information. A resistive layer covers the front wall so that the instantaneous position of the pen can be fed through bus bars to a computer. This computer compares the electrical version of an observed signature on the display with a stored signature.

Abstract: A bridge module is preassembled from girder sections the type disclosed in Pat. No. GB 1209747, and integrated by stabilizing means so as to provide a crane-assisted building method which is less labor intensive and less time consuming than known manual methods.

Abstract: A double base propellant composition having well-platonized ballistics at low burning rates consists of nitroglycerine (NG), nitrocellulose (NC) at least one lead compound and at least one copper (II) salt of an aliphatic dicarboxylic acid. The copper salt preferably comprises copper succinate, and the lead compound may include any of those known as ballistic modifiers in the propellants art. A preferred composition, having a platonized burning rate of 2.3 mm s.sup.-1 at a chamber pressure of 2-3 MPa, comprises by weight 35.1% NC (12.6% nitrogen), 41.6% NG, 8.3% triacetin, 10.7% sucrose octa-acetate, 0.3% 2-nitrodiphenylamine, 1.2% p-nitromethylaniline, 1.0% copper (II) succinate and 1.8% lead acetophthalate.

Abstract: A reuseable collector for use in a process for the bulk production of alloy by deposition from the vapor phase. The collector employs a coating of solder alloy on the deposition surface such that after deposition has been completed the solder alloy may be melted and the deposited alloy removed from the collector without the necessity of destroying the collector.

Abstract: A projectile suitable for firing from a gun barrel contains an additive which is dispensed along the gun barrel by the pressure of a gas propellant so as to reduce barrel wear. A charge of additive (11) is stored within a cylindrical recess in the rear face (12) of the projectile. In use, the pressure of the gas propellant acts on a nylon piston (6) slidably located within the tube (2), which piston in turn pressurizes the charge (11) forcing it forward through the four extrusion ports (9) to the exterior of the projectile. The charge additive (11) is preferably a mixture of a thermal insulator and a lubricant, best characterized by silicone oil or a paste mixture of titanium dioxide and silicone grease. The invention is particularly applicable to small arms bullets for firing from a rifled gun barrel, and may be incorporated in existing hollowed bullets, for example tracer bullets.

Abstract: There is provided a method of producing inorganic thin films by metal inorganic chemical vapor deposition. The method comprises forming a vapor stream comprising a vapor mixture of an organometallic compound and a heterocyclic organic compound incorporating a group V or group VI element, and thermally decomposing the mixture on a heated substrate to form an inorganic layer. The heterocyclic compound may be an aliphatic or aromatic ring compound. The mixture may include vapors appropriate for deposition of ternary or higher order compounds, and/or for introducing dopants.

Abstract: An antenna array comprises a dielectric image waveguide (3) acting as a feeder, which may be of the insular or inverted-strip type, in contact with a dielectric sheet (1). On the sheet (1) is located a plurality of strips (4) of metallizing extending outwards from the feeder-guide (3). The inner ends of the strips are located to couple with the feeder-guide and their outer ends act to radiate or receive most of the power. Preferably the mode propagated in the feeder-guide is an E.sub.mn.sup.y mode higher than the fundamental, suitably the E.sub.21.sup.y mode.

Abstract: A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye characterized in that the dye comprises at least one anthraquinone compound free from water-solubilizing and ionic substituents and having the formula: ##STR1## wherein each of R and R.sup.1 independently represents an n-alkyl group having from 4 to 7 carbon atoms inclusive and wherein each of R.sup.2 and R.sup.3 is independently selected from hydrogen and alkyl groups having from 1 to 4 carbon atoms inclusive.

Abstract: A projectile for dispersing a riot control agent material into the atmosphere at a target. The projectile is designed to open in flight and scatter a number of independent dispersal charges over a limited target area, and comprises a sabot in the form of a number of segments which are locked together prior to launching, which contains the dispersal charges and a delayed opening means which initiates opening in flight, thereby releasing the charges along approximately the same trajectory as the former projectile. In a preferred embodiment the sabot is cylindrical, in two segments hinged together at their rear end, locked together by either a collar or a pin and socket arrangement, and containing a number of cylindrical charges in line, with an axial channel. The projectile is fired from a gun, and firing initiates a pyrotechnic delay which activates an explosive or pyrotechnic charge in the channel and between the charges to open the sabot and activate and disperse the charges.