Abstract: A wind turbine is provided having a lidar wind speed measurement apparatus for achieving wind control. The lidar apparatus is arranged to scan the area in front of the wind turbine so as to generate a measurement of the wind speed across the wind field. The lidar apparatus may be located in the hub of the wind turbine and the look direction inclined away from the rotational axis so that rotation of the hub ensures scanning. Preferably the lidar apparatus has a plurality of look directions so as to increase the scanning rate. This may be achieved by having a number of dedicated lidar systems and/or by using multiplexed lidars. Measurement of the wind field allows improved control of the wind turbine giving efficiency and reduced wear benefits.

Abstract: A vibration sensing device, an acceleration sensing system and a method of manufacturing a vibration sensing device wherein the vibration sensing device comprises a flexible disk that is mounted symmetrically about a radial plane and has a mass located on the disk substantially symmetrical about this radial plane which exerts a force that is greater towards the edge than it is towards the centre of the disk. The vibration sensing device is sensitive to on-axis signals and insensitive to cross axis signals.

Abstract: A mid-infrared emitting indirect bandgap quantum well semiconductor laser with an optical waveguide structure having an active waveguide core. The active waveguide core comprises at least one repetition of a sub-region comprising in the following order a first wide bandgap layer, a first conduction band layer of InAs, a valence band layer of Ga(1-x)InxSb where x?0.7, preferably of InSB (ie. x=1), having a thickness of less than 15 Angstroms, a second conduction band layer of InAs and a second wide bandgap barrier layer. The barrier layers co-operate to provide electrical confinement for the carriers within the intervening conduction band and valence band layers and optical confinement in the active core region is provided by the optical waveguide structure.

Abstract: This invention relates to various phosphine oxides and their use in applications which exploit the triboluminescent effect.

Abstract: A photodetector circuit incorporates an avalanche photodiode structure having a contact layer (14) forming an ohmic contact over an annular region (18) with the annular guard ring (8). In the fabrication process, the starting substrate can either be the handle wafer of a p? silicon-on-insulator wafer, or a p-Si substrate with an insulating SiO2 layer (4). A window (6) is produced in the insulating layer (4) by conventional photolithographic and etching. A n+ guard ring (8) is created by diffusing donor impurities into the substrate, and a thinner insulating SiO2 layer (22) is thermally grown so as to cover the exposed surface of the substrate within the window (6). P-type dopant is then implanted through the thin oxide layer to increase the doping level near the surface of the substrate. Subsequently a second window (24) is made in the insulating layer (22), and the layer (12) is then epitaxially grown selectively on the area of the substrate exposed by the window (24) in the insulating layer (22).

Abstract: A detection device that can be used for detecting objects behind clothing etc including a dielectric lens and a receive element sensitive to millimetre wave radiation. Prior art systems produce an image of a scene usually using scanning optics. This can be large and expensive. The present invention instead take spot readings from different parts of a scene without building up an image. The spot readings are processed, and an indication given to a user if certain characteristics of the readings are observed. Typical characteristics used are the differences in absolute received power level, and the power level at different polarisations. Such characteristics are typically present is an object of interest is in the scene. Also disclosed are various methods of altering the received beam to get readings from different areas from the scene, such as changing the beam width, or beam angle.

Abstract: A method of controlling the switching of an optically addressable spatial light modulator (OASLM), to a first surface of which a write light signal is applied and to a second surface of which a read light signal is applied. The method comprises applying a bipolar switching waveform to control electrodes of the (OASLM) during each write cycle such that the leading pulse of the waveform applies a voltage across the (OASLM) which is in the photosensitive direction and the trailing pulse applies a voltage which is not in the photosensitive direction.

Abstract: A liner for a shaped charge having a composition comprising greater than 90% by weight of powdered tungsten and up to 10% by weight of powered binder, the composition being formed into a substantially conically shaped body and having a crystal structure of substantially equi-axed grains with a grain size of between 25 nano-meters and 1 micron.

Abstract: A man portable hydrogen source, the source comprising one or more hydrogen generating elements (2), an ignition control system (3) and a pressure vessel (1). Each hydrogen generating element comprises a pellet holder (7) provided with one or more recesses and a thermal insulation layer (9) to reduce heat transfer to adjacent hydrogen generating elements; wherein at least one recess contains a pellet (8) of a chemical mixture which on thermal decomposition evolves hydrogen gas; wherein the ignition control system comprises one or more ignitors (14), associated with an individual pellet (8), and activation means to activate the ignitors; and wherein the evolved hydrogen and hydrogen generating elements are contained within the pressure vessel.

Abstract: In an active semiconductor backplane for a liquid crystal spatial light modulator, spacers (25) which are distributed over the backplane extend above an array of electrical and/or electronic elements and comprise at least two layers essentially of the same material and occuring in the same order as is found in at least one of the electrical or electronic elements, such as an NMOS transistor (52). The latter is formed from a stack of layers on a silicon substrate (51) comprising polysilicon (56), continuous silicon oxide (57) modified to include gate oxide GOX (55), metallic gate electrode (59), continuous silicon oxide (58) and a metallic drain electrode (60) which is coupled to a spaced mirror electrode over the layer (58). Likewise, spacer (25) comprises the layers (57 and 58) with metallic (67, 68) deposited simultaneously with electrodes (59, 60). The foot of layer (57) is differently modified to include field oxide layer (69) and polysilicon layers thin oxide (71).

Abstract: An Array of detectors can be configured to be read as separate detectors, or to be connected into larger groups, e.g. groups of four (a 2×2 array). This allows the formation of a relatively high definition image, and a much faster formation of a lower resolution image. This may be used with in an automobile to control deployment of safety airbags in accordance with a drivers position relative to the airbags. Preferably the array is a 64×64 array of thermal detectors.

Abstract: A photonic light circuit device is described that comprises a semiconductor substrate (220) and two or more optical components (226, 228, 236, 240) wherein one or more hollow core optical waveguides (230, 232, 224) are formed in the semiconductor substrate to optically link said two or more optical components. The PLC may comprise a lid portion (44) and a base portion (42). The PLC can be adapted to receive optical components (8: 608) or optical components may be formed monolithically therein. Coating with a reflective layer is also described.

Abstract: Frequency compensated communications reception includes compensating for frequency offset in a received signal by constructing a reference signal for comparison with a training sequence in a received signal. The reference signal is formed from basis functions and the training sequence. It is obtained by minimising a cost function J constructed from an adaptively weighted combination of basis functions, the training sequence, the received signal and a constraint requiring non-zero signal power. Multi-element antenna signals are weighted with a beamforming weight vector w in J given by formula (I), where X is a matrix of received signal samples, C is a diagonal matrix containing elements of the training sequence, F is a matrix having columns defining basis functions, v is a vector of adaptive weights, index H indicates complex conjugate transpose and ? is a Lagrange multiplier constraining beamformer power.

Abstract: The invention relates to various materials and their use in applications which exploit the triboluminescent effect.

Abstract: A method of determining the rate of change of optical thickness of a thin-film during deposition comprising the steps of illuminating the thin-film (5) with electromagnetic radiation (3) having a range of wavelengths, measuring the transmission spectrum (6,7) of the thin-film (5) at least twice during the deposition process to determine the wavelength ?t or turning points in the transmission spectrum, and using the measurements to determine the rate to change of optical thickness of the thin-film as a function of time. The method further comprises the steps of predicting a time T in the growth process at which the wavelength ?t of the turning point in the transmission spectrum of the thin-film will be substantially equal to the wavelength ?d of the turning point in the transmission spectrum of thin-film at its optical design thickness, and interrupting the growth process such that growth ceases at time T.

Abstract: Triboluminescent materials comprising M wherein M is chosen from Tb, Eu, Sm, Dy and from 75% to 99.99% of M is replaced by Y, Gd, La or Lu.

Abstract: A method of generating a Computer Generated Hologram (CGH) using the diffraction specific algorithm allows a curved wavefront to be produced from a single hogel, rather than the planar waves of the prior art. This allows a wavefront from a singel hogel to generate a point in the image volume. An imaginary wavefront is transmitted from each point in the image volume and sampled at a plurality of points over the hogel. These samples are used to produce a set of complex Fourier coefficients that can be used to approximate the original waveform.

Abstract: Radiometers detect radio wavelength electromagnetic radiation and typically have an antenna (16), an amplifier (18) and a detector (20). All three of these components have response characteristics that may be dependent on temperature, and in the case of systems using radiometer arrays dependent upon temperatures throughout the system. Different temperatures across a multi-channel antenna and differential channel temperature response can result in poor image quality from imaging radiometers. Resolution of a linear array of detector horns is limited by the size of the horns.

Abstract: A phase shifter device comprising a substrate defining a slot line waveguide having first and second ends and being operably coupled to a microstrip waveguide and a shorting patch is described. The microstrip waveguide and shorting patch are moveable along the slot line waveguide so as to vary the distance between the first end of the slot line and the intersection of the slot line waveguide and microstrip waveguide whilst maintaining a substantially constant separation between the microstrip waveguide and the shorting patch. A separation between the microstrip waveguide and shorting patch equal to one quarter of the effective wavelength of the radiation carried by the device is described. The device is described for use in various phased array antenna systems.

Abstract: A coherent laser radar device is described which comprises a laser source (11), and two or more transceivers (84) are optically connected to the laser source by optical fiber cables (42, 48, 82) that are routed through an optical routing means (80). A detection means (27) is also provided, and radiation received by the two or more receivers (84) can also be optically coupled to the detection means (27) by optical fiber cables (82, 86, 90).