Abstract: R.sub.1 --A--(X).sub.m --(B).sub.n --R.sub.2 (I)R.sub.3 --J--(Y).sub.p --(Z).sub.q --R.sub.4 (II)Liquid crystal compounds of formula (I) are described, where formula (I) is given as R.sub.1 --A--(X).sub.m --(B).sub.n --R.sub.2 where A is selected from nathyl, fluorinated naphthyl, brominated naphthyl, B is selected from phenyl, methylated phenyl, brominated phenyl, fluorinated phenyl, thiophene, pyrimidine and pyridine, R.sub.1 and R.sub.2 are independently selected from alkyl, alkoxy, alkynyl, thioalkyl, Br, CN, SCN, NCS, perfluoroalkyl, perfluoroalkoxy and hydrogen, X is selected from C.tbd.C, COO and C.tbd.C, m is 0 or 1, n is 0 or 1 where m is 1 and n is 0 where m is 0; provided that where A is naphthyl, n is 1 and m is 0 then B is selected from methylated phenyl, brominated phenyl, thiophene, pyrimidine and pyridine; and further provided that where A is naphthyl, X is C.tbd.C, m is 1 and n is 1, then B is selected from thiophene, pyrimidine and pyridine.

Abstract: Textile materials having radar attenuating properties based upon a polymer enclosed scrim having hollows which are at least partially filled with radar attenuating material. The scrim is sandwiched between two or more polymeric layers, the spaces being the interstices of the scrim. Suitable radar attenuating materials for inclusion in these spaces include carbon granules, carbon fiber, carbonyl iron, ferrites or metal coated microspheres. Carbon fiber is conveniently used in chopped or otherwise relatively short fiber form. The textiles offer lightweight with equivalent radar attenuation performance to known textiles and may include further radar attenuating material in polymeric components to provide enhanced attenuation effect.

Abstract: A toxic work enclosure (1) with a port (14) and a vent (18) that when installed within a fume cupboard (64) with both the port (14) and the vent (18) open, provides safe access to toxic materials, if present, in the toxic work enclosure (1); but with both the port (14) and the vent (18) closed, closed position isolates the toxic work enclosure (1) allowing environmental control of the air (104) within the toxic work enclosure (1), or safe removal of the toxic work enclosure (1) from the fume cupboard (64) by containment of toxic materials, if present, in the toxic work enclosure (1).

Abstract: Tracking means for establishing a line-of-sight between a control point towards which the second craft is being guided and tracking the line-of-sight to follow the second craft and deriving a signal .theta..sub.a representing the rate of rotation of the line-of-sight about the control point; monitoring means for deriving a signal e representing the displacement of the first craft from the line-of-sight, a signal representing the range R.sub.m from the control point to the first craft and a signal representing the rate of of change R.sub.m of the range R.sub.m ; ranging means for deriving a signal representing the range R.sub.t from the control point to the second craft and a signal representing the rate of change R.sub.t of the range R.sub.t ; a computer for deriving representations of .theta..sub.c, .theta..sub.c and .theta..sub.c which satisfy the equation.sub.c =-2.theta..sub.c.sup.3 -3.theta..sub.c (R.sub.t /R.sub.t)where the difference .theta..sub.c -.theta..sub.

Abstract: A lightweight acoustic enclosure (1.1), for the reduction of noise transmission from monopole, quadrapole and higher order noise sources via airborne paths at frequencies lower than the approximate ring frequency of the enclosure (1.1), comprising an approximately spherical shaped enclosure (1.1), which is made from stiff materials to reduce the amount of stretching of the enclosure wall and substantially encases the noise source, all structural paths between the enclosure and the noise source comprising vibration isolation (2.4). The thickness of the enclosure wall can be relatively thin. The enclosure (1.1) can comprise multiple concentric layers of stiff material, ideally with adjacent layers having at least one compliant layer, such as foam rubber, sandwiched between them. The enclosure (1.1) can comprise several component parts such as spherical shell elements (1.2), with radii less than that of the approximate radius of the enclosure (1.1). Additional webbings or flanges (1.

Abstract: A method for producing hollow diamond tubes by diamond growth using chemical vapor deposition (CVD) techniques. Suitable substrate material, such as tungsten, molybdenum, copper or silicon, typically in the form of wire, having diamond nucleation sites is formed into a helix. The helix is then placed, or moved through, a CVD chamber for deposition of diamond on the helix. Suitable pitch and diameter of helix results in deposition diamond on the helix until such time as the growth surfaces of the diamond fuse to form a hollow diamond tube.

Abstract: A method is provided for determining the presence and/or amount of a microorganism and/or its intracellular material present in a sample performed by: (a) exposing the sample to a specific binding agent that has been immobilized upon a solid substrate, the specific binding agent being capable of binding to the microorganism or its intracellular material such that it becomes associated with the solid substrate, (b) exposing the solid substrate to an agent capable of making adenylate kinase associated with the microorganism and/or its intracellular material accessible to solutions applied to the substrate, (c) applying a solution containing adenosine diphosphate (ADP) to the substrate under conditions whereby adenosine triphosphate (ATP) may be produced by any adenylate kinase present, and (d) measuring the amount of adenosine triphosphate (ATP) and relating that to the presence and/or amount of microorganism or intracellular contents.

Abstract: A nematic liquid crystal device with two bistable switched states, having two cell walls treated which provide a bigrating on one or both cell walls. The bigrating enables the liquid crystal molecules at a surface to lie in two different angular directions, 45 or 90 degrees apart. The bigrating may be symmetric or asymmetric, with the surface energy of each of the gratings of the bigratings being nearly equal.

Abstract: A speech training aid compares a trainee's speech with models of speech, stored as sub-acoustic word models, and a general speech model to give an indication of whether or not the trainee has spoken correctly. An indication of how well the word has been pronounced may also be given. An adult operator enters the word to be tested into the training aid which then forms a model of that word from the stored sub-word speech models. The stored acoustic models are formed by first recording a plurality of words by a plurality of trainees from a given list of single words. These recordings are then processed off-line to give a basic acoustic model of an acceptable or correct sound for each phoneme in the context of the pre-and proceeding phonemes. The acoustic models are Hidden Markov Models. The limits of acceptable pronunciation, applied to different words and trainees, may be adjusted by variable penalty values applied in association with the general speech acoustic model.

Abstract: A method and apparatus for monitoring a gaseous environment for the presence of cellular material capable of providing a measure of presence and/or numbers of cellular microorganisms, such as bacterial cells, in a large volume of air such as in a warehouse or production facility or in an open air location where bacterial presence is suspected. The method and apparatus are particularly suited for determining the likelihood of pathogenic material being present in an environment by batch or on-line measurement of cell numbers. On-line measurement provides continuous monitoring of an environment for presence of pathogens. The device includes a continuous flow luminometer preferably fed by a cyclone or high velocity virtual impactor and lytic and luminescence reagents which detect the amount of ATP or adenylate kinase present in a sample of air.

Abstract: A method for the detection of chemical agent present in a material comprising exposing a calixarene, having redox active substituents on its para rim, to a solution or suspension derived by admixture of all or some of the material with a liquid measuring any change in electrical behavior of the calixarene during or after exposure to the solution or suspension as compared to a reference condition, and relating such change in electrical behavior to the presence of chemical agent. Preferably, the calixarene exposed to the solution or suspension is a calix?4!arene or general formula (J), wherein Y.sup.1 to Y.sup.4 are independently selected from hydrogen, alkyl, alkenyl, aryl, aralkyl or a redox active substituent and R.sup.1 to R.sup.4 are independently selected from hydrogen, alkyl, alkenyl, aryl, aralkyl, or a polymerisable moiety, wherein at least one of Y.sup.1 to Y.sup.4 is a redox active substituent.

Abstract: A twisted nematic type of liquid crystal device comprises two cell walls enclosing a layer of a nematic or long pitch cholesteric liquid crystal material. The device has both an alignment direction and a surface tilt provided by an asymmetric grooves structure alignment on one or both walls. The alignment treatment may be provided by a shaped layer of a photolithographic material. Embossing, ruling, or transferred from a carrier layer material may alternatively provide the alignment. The amount of twist may be multiples of about 90.degree. and the device arranged between two polarisers.

Abstract: An optical component having a protective layer provided on a surface thereof, the protective layer preventing the component from being damaged by high velocity impacts from small particles or water droplets. The protective coating comprises a layer of gallium phosphide deposited onto the component surface using plasma assisted chemical vapour deposition (PACVD), an intermediate layer of PACVD boron phosphide, and an outer layer of PACVD diamond-like-carbon.

Abstract: A liquid crystal display element using ferroelectric liquid crystal includes a light blocking thin film which is formed by silicon or silicon-germanium solid solution by evaporation between electrodes formed by an ITO film placed in a striped pattern on a surface of a transparent glass substrate so that the thin film does not protrude from the ITO film surface. This thin film shades a non-pixel region as a black matrix.

Abstract: A ferroelectric liquid crystal device comprises a layer of a ferroelectric liquid crystal material contained between two cell walls carrying electrode structures and a surface alignment treatment. The surface alignment is provided by a profiled surface, e.g., a grating, on at least one cell wall. The grating may be a monograting or a bigrating, with a symmetric or asymmetric profile. Such a profiling enables surface tilt and alignment anchoring energy to be independently arranged to suit liquid crystal material and device type to give a required molecular arrangement and low device defect. The grating may be provided by interferography, photolithography, embossing, ruling, or carrier layer transfer. Alignment directions on the cell walls may be parallel or non-parallel. The surface tilt on both cell walls may be the same or different values. The cell walls may be relatively rigid, e.g., glass slides, or flexible, e.g.

Abstract: The present invention relates a method for the detection, identification and/or quantification of plant or animal tissues, microorganisms or cell free RNA or DNA and to detector apparatus adapted for performing said method. The method particularly uses Total Internal Reflection Fluoresence (TIRF) to measure hybridization of analyte RNA or DNA with RNA or DNA that is associated with an evanescent wave detector waveguide.

Abstract: An all-solid-state laser comprising a slab (1) of gain medium, a diode laser pump system (3) configured in an end pumping geometry with the gain medium (1) and a heat sink thermally contacted to the gain medium (1) wherein the diode laser pump system (3) and the gain medium (1) are cooperably arranged so that in use a positive thermal lens is capable of being formed within the medium, the gain medium (1) having a thickness (d-d') made as small as possible while permitting the substantially unhindered passage through the slab of the laser mode established between the two mirrors (M1, M2).

Abstract: A radiation sensor (10) for the microwave and millimeter-wave regions incorporates a lens (12) having two parallel focal planes (26a, 36), these being defined by a polarization-selective reflecting PIN diode array (18) within the lens (12). One focal plane (26a) is occupied by a receive array of crossed dipole antennas which mixes receive signals and a local osicllator signal to produce intermediate frequency signals for subsequent processing. The second focal plane (36) is occupied by a transmit antenna array of separately activatable polarization switching antennas arranged to define a range of transmit beam directions. A second PIN diode array (20) protects the receive antenna array from the transmit beam.

Abstract: A method of applying a stable intermetallic diffusion barrier layer to a metallic article is described. In many instances, protective coatings are incompatible with the material of the substrate to which they are applied. Such incompatibility is overcome in the invention through in situ formation of an intermediate stable diffusion barrier layer by sequential deposition and subsequent reaction of suitable metals to form a continuous intermetallic layer. A conventional overlay coating may then be applied to the intermetallic layer without risk to the underlying substrate. The invention also contemplates creation of unitary diffusion barriers from multi-layer deposits; deposition of plural diffusion barriers, and formation of complete protective systems comprising substrate, diffusion barrier(s) and overlay coating prior to heat treatment in situ.

Abstract: The invention provides a ferro-electric liquid crystal display (FLCDs) with reduced voltages requirements for driver circuits. This enables standard drivers circuits designed to rms address twisted nematic type of displays, to be used for FLCDs. Displays are formed by cells containing smectic liquid crystal material. The cell walls are surface treated and carry e.g. row and column electrodes forming an x,y matrix of addressable display elements. The smectic liquid crystal material switches between two states upon application of a dc pulse of appropriate amplitude, polarity, and time. Addressing waveforms are strobe waveforms, e.g. two pulses of opposite polarity in successive time slots, applied to each row in turn. Data waveforms are, e.g. dc pulses of alternate polarity with each pulse lasting one time slot ts. Two data waveforms are needed to switch between the two states; one data waveform is the inverse of the other. Typically a strobe waveform pulse may be 50 volts.