Abstract:
A method for making a fibre electrically conductive comprises the steps of: (a) providing a fibre having a negative electric charge at the surface of the fibre, (b) applying to the fibre a substance (such as a polyelectrolyte) which provides a layer of said substance on the fibre and changes the electric charge at the surface of the fibre from negative to positive, wherein said substance is not chitosan, and (c) making the surface of the fibre electrically conductive with a metal, wherein the metal of step (c) is provided in the form of metal ions and wherein a reducing agent (for example) is employed to reduce the metal ions to elemental metal. Fabrics formed from conductive fibres are also provided.
Abstract:
A position detection system is able to detect the three dimensional position of at least one target(10). Each target (10) is configured to act as a retro-reflector for light incident from any direction. At least one light emitter illuminates the at least one target (10) and at least one detector(24)is provided for detecting and taking measurements of light retro-reflected from a target(10). There is also provided a processor for processing measurements taken by each detector(24)to determine the three dimensional position of the at least one target (10).
Abstract:
A high capacity capacitor (10) include a spacer element (18) formed of a high energy density dielectric material, specifically doped bismuth ferrite. The additive includes strontium and titanium. The doping agent has the effect of increasing the difference between the saturation polarisation and the remnant polarisation of bismuth ferrite as well as reducing charge leakage, making bismuth ferrite a suitable material for a high energy density capacitor. The doped bismuth ferrite exhibits good temperature stability.
Abstract:
A method of detecting a deviation of a condition of a plurality of regions of a substrate or device using compressive sensing is disclosed. The method can include applying a sequence of patterns of light to the plurality of regions, detecting an interaction of the light with the plurality of regions, and detecting a deviation of a condition of the plurality of regions from a desired condition.
Abstract:
A display includes a waveguide (12), a first holographic element for coupling display light into the waveguide (12) and a second holographic element for receiving the display light from the first holographic element and for coupling the display light out of the waveguide (12) to display the display light to a user at a viewing position (20). The first and second holographic elements can have a material structure size of substantially ≤ 20nm. The display can include a programmable spatial light modulator (44) operable selectively to cause display light to convey a desired image. The display can include a variable focus optical element to selectively vary the apparent position of an image. Methods of operating a display are also provided.
Abstract:
A substrate includes a diffracting structure providing a hologram (20, 6). The diffracting structure encodes a holographic image so that thatholographic image is produced in response to reference light being incident on a major surface of the substrate at an angle of incidence with respect to the said major surface of the substrate, wherein the angle of incidence is no more than 20°.
Abstract:
A smart antenna includes a plurality of parasitic antenna elements provided with varactors, a voltage supply arranged to be coupled to the varactors and operable to supply a DC voltage, and a control unit operable to tune DC voltages applied to the varactors, wherein each parasitic antenna element can be reconfigured either as a reflector or a director on the basis of the voltage applied thereto. The driven element is surrounded by first and second 10 annular arrays of parasitic elements at radii of substantially 25 and 50 mm respectively, each annular array including six antenna elements. The array is configurable for steering the beam. The arrangement is compact and efficient.
Abstract:
A measurement device comprises a high permittivity dielectric resonator (10) with a low microwave loss tangent and having at least a first symmetry axis (z-i ); an electrically conductive resonance chamber (100) containing and geometrically similar to the resonator (10) and having a second symmetry axis (z2) coincident with the first symmetry axis (z-i ); the resonance chamber (100) having a plurality of similar ports (104) orthogonal to the first symmetry axis (z-i ), each such port (104) having a microwave antenna (1 14), either to inject microwaves into the resonance chamber, thereby to excite an electric field in the resonator, or to receive microwaves from the resonance chamber; and a comparator circuit (200, 300, 400, 500, 600, 700, 800) connected to a first one (P1 ) of the plurality of ports (104) to inject microwaves into the resonance chamber and to another (P2, P3) of the plurality of ports (104) to receive microwaves from the resonance chamber; wherein the measurement device further comprises an electrically conductive tuning screw (106) in electrical contact with the resonance chamber (100), the tuning screw being at least partially positionable in the electric field thereby excited in the resonator; and a source of magnetism (18) to apply a magnetic field to a sample brought into proximity with a top surface (12) of the resonator (10) substantially parallel or anti-parallel to the first symmetry axis (z-i ); and wherein one (P3) of the other of the plurality of ports (104) to receive microwaves from the resonance chamber (100) is orthogonal to the first one (P1 ) of the plurality of ports (104) to inject microwaves into the resonance chamber. Such a measurement device may be used to measure both the conductivity or sheet resistance of a thin film (30), as well as the carrier mobility of the thin film, without contacting the resonator (10) with either the thin film or a substrate (20) on which the thin film is formed.
Abstract:
A local clock network (10, 12) has a reference control unit (16a, 16b) having a reference clock, processing unit and data memory. Coupled to each reference clock (16a, 16b) by a fibre optic cable (20a 1 -20a n and 20b 1 -20b n ) are a plurality of remote stations (22a 1 -22a n and 22b 1 -22b n ), typically clients desiring an accurate clock signal which is precisely and reliably synchronised with the local clock signal of other users within the network or interconnected networks. The user units (22a 1 -22a n and 22b 1 -22b n ) are in the form of a clock indicator unit which provides a clock signal for use by the internal client systems. Each network (10, 12) is a closed loop system between the associated reference station (16a, 16b) and the associated remote user stations (22a, 22b). Each reference station (16a, 16b) determines the latency associated with each remote user station (22a 1 -22a n and 22b 1 -22b n ) and generates an offset appropriate for each user station (22a 1 -22a n and 22b 1 -22b n ). Each reference station (16a, 16b) then generates a specific clock signal for each remote user station (22a 1 -22a n and 22b 1 -22b n ) on the basis of its reference clock signal adjusted by the appropriate user station offset. The local user time clocks are thus precisely synchronised to one another. A plurality of separate networks (10, 12) are synchronised by reference to their local Coordinated Universal Time (UTC) clocks, with one reference station acting as a master station.
Abstract:
An antenna system includes a plurality of antenna assemblies. The antenna assemblies include a driven component and a director array to increase the gain of the antenna assembly. For each antenna assembly of the plurality of antenna assemblies, the driven component and director array are disposed in an antenna plane. Each antenna assembly is arranged in a different geometrical plane.