Abstract: An electrical contact formed in a groove in the surface of a semiconductor material facilitates an advantageous contact with the material for a given cross-sectional area of contact when compared with a contact of the same cross-sectional area formed on the surface of the material. The grooved contact significantly reduces shading of the surface of the semiconductor material compared with an equivalent surface contact.

Abstract: A leg holding and positioning device for use in surgical operative procedures comprising a housing (10) which is adapted for attachment to the rail (12) of an operating table (not shown) by means of a member (11) and a clamp (13) the housing having projecting from it a shaft (14) which is connected to a viscous damper or other device within the casing (10) to control rotation of the shaft (14), such device being associated with the control knob (18) whereby the shaft may be fixed in any one of a number of rotated positions. A member (25) is attached to one end of the shaft (14) and in use lies alongside the operative leg of a person on the operating table, the leg being secured to the member (25) by means of the bracket (32) and straps (35) and (36).

Abstract: A new logic circuit construction in which gates are formed by appropriate interconnections of complementary current-mirror cells. With a signal applied, the resulting logic circuit draws a current drain which rises with power supply voltage, as does the speed of the circuit. With no signal the current drain of the circuit is small. Clocked circuits using this logic can use one clock line. With three states available in the clock line, a non-overlapping two-phase clock is automatically obtained with a simple oscillating signal. This logic circuit is also capable of providing a weighted input or output, enabling threshold logic ("multiple-valued logic") to be performed.

Abstract: The generation of X-radiation occurs when a powder (14,24,38,47,58) is sucted to electro-dispersion in an evacuated chamber. The powder is of a conducting or semiconducting material, and is supported on the lower of two electrodes (10,11; 22,25; 36,39; 44,48; 52,56) in the chamber. When the chamber pressure is about 10.sup.-5 Torr or lower, and a high voltage is applied across the electrodes, part of the powder forms a dispersed particulate cloud in the space between the electrodes. The dispersion of the powder results in the generation of X-radiation which is transmitted through the wall (13) of the chamber or through a window (28,35,45) in the apparatus. Visible light is produced if a phosphor (29) is included in the chamber, and is irradiated by X-rays generated upon dispersion of the powder, or if the powder includes particles of a phosphor.

Abstract: An ion or electron beam is steered or focussed by a circular magnetic field produced by passing a large electrical current through a straight conducting wire, the magnetic field being co-axial with the wire. Annular beams of charged particles coaxial with the straight wire can be focussed onto a circular spot or, depending upon the entry radius of the annular beam and the magnetic field strength, can be induced to follow a looping trajectory. The effect of the steering or focussing system can be enhanced by the provision of a cylindrical conductor which is co-axial with the straight conducting wire and maintained at a voltage sufficient to produce the desired particle trajectory such that the particle beam passes between the wire and the cylindrical conductor. The beam steering or focussing systems is applicable to the fields of beam current density intensification, ion implantation, ion separation and free electron lasers.

Abstract: The present invention is directed toward a building material comprising from 20 to 70% of a reactive amorphorous silicate material which has been reacted with an aqueous solution of an iron salt, from 20 to 60% by weight of a filler containing reactives polyvalent cations, from 10 to 50% by weight of lime and from 0 to 10% by weight of reinforcing fillers, and to a method of producing same.

Abstract: An ion or electron beam is steered or focussed by a circular magnetic field produced by passing a large electrical current through a straight conducting wire, the magnetic field being co-axial with the wire. Annular beams of charged particles coaxial with the straight wire can be focussed onto a circular spot or, depending upon the entry radius of the annular beam and the magnetic field strength, can be induced to follow a looping trajectory. The effect of the steering or focussing system can be enhanced by the provision of a cylindrical conductor which is co-axial with the straight conducting wire such that the particle beam passes between the wire and the cylindrical conductor. The beam steering or focussing systems is applicable to the fields of beam current density intensification, ion implantation, ion separation and free electron lasers.

Abstract: A communications system suitable for use as a local area network (LAN) is provided wherein the network has a ring topology comprising a plurality of nodes 10 each of which is connected to adjacent nodes by links 14 and 15. Each node comprises a Link Interface Unit (LIU) 11, a Network Interforce Unit (NIU) 12 and a Terminal Interface Unit (TIU) 13. By providing forward and reverse links 14, 15 between nodes the system is capable of reconfiguring itself after link or node failure such that the failed equipment can be bypassed to minimize system disruption. Link Interface Units (LIU) 11 are also capable of bypassing their own node if a node failure is detected. System control is decentralized with each active node contributing to system control such that prime-failure sites are avoided.

Abstract: A yarn twist measurement device having a freely rotatable disc with its axis parallel to the axis of a travelling yarn. The disc being rotated by the surface twist of the yarn in contact with the circumference of the disc as the yarn travels past the disc. By measuring the circumferential displacement of the disc and the corresponding linear translation of the yarn, the amount of twist on the surface of the yarn can be calculated.

Abstract: A method and device for determining the clotting time for a sample of whole blood. A sample of whole blood is placed in a cuvette (12) which is centrifuged in a centrifuge (11) to mix the blood sample with a coagulant in the cuvette (12) and simultaneously spin out the cells in the blood. The optical density of a part of the sample which is cleared of cells by the centrifugation is monitored using a light source (14) and a light detector (15) and the time measured for optical density indicative of clotting to be reached by a timer (25).

Abstract: Grooved solar cells are manufactured by scribing the surface of the substrate with a laser scribing tool, and optionally etching the surface to more accurately determine the surface profile, before performing the remainder of the processing steps involved in the production of the solar cell. Top contact shading is avoided by providing holes through the substrate which allow connection to the top layer of the cell to be made from the back of the cell. Resistance to radiation is improved by providing a cell which is grooved on the top and bottom surfaces, the grooves of the bottom surface being spaced between the grooves on the top surface to allow the formation of a relatively thin cell structure. Top layer sheet resistivity is also varied to allow improved efficiency while maintaining the series resistance of the cell substantially unaltered.

Abstract: A new detection configuration devised for the Scanning Electron Microscope (SEM), which allows the imaging of the surfaces of a specimen at atmospheric pressure. Such a detection configuration gives rise to a new microscope: the Atmospheric Scanning Electron Microscope (ASEM). In this configuration the detector means, such as a backscattered electron detector, is placed between the pressure limiting aperture and the electron column. The electron beam passes through the final aperture, reaches the sample under atmospheric conditions and the backscattered electrons (or other signals) are allowed to reach the detector. The new configuration makes it possible for specimens or materials to be viewed in an open room. Examination of materials, not only in their natural state but also in their natural position, is possible. This feature of the ASEM will be extremely useful in areas where sampling is impossible, expensive or critical for the test subject, e.g.

Abstract: A Passivated Emitter Solar Cell (PESC) with reduced surface recombination due to reduced contact area between the top metal contact and the top surface of the cell, and having an open circuit voltage approaching 700 mV and an energy conversion efficiency in excess of 19% is disclosed. The reduced contact area is obtained by a technique which simultaneously defines the lateral geometry of the top metal contact while allowing the top metal contact to be of much larger area than the area of contact to the top surface of the cell. Also disclosed are methods of manufacture of solar cells having an increased open cell voltage obtained by improved passivation of the cell surface obtained by this technique.

Abstract: A method of directly detecting amino acids, other organic and inorganic copper-complexing agents, and indirectly detecting non copper-complexing species comprising use of a potentiometric flow-through electrode detector suitable for use in high performance liquid chromatography and autoanalyzers. Said detector comprises a copper metal indicator electrode and a suitable reference electrode within a miniature flow through cell and which detector has the property that it provides a voltage response to the particular molecule to be detected thereby.

Abstract: A method and apparatus for non-destructively measuring twist in a translating yarn (2) by means of a blade (1) which is in rubbing contact with the translating yarn (2) so that vibrations are imparted to the blade (1). The frequency of vibration of the blade (1) provides a measure of the twist imparted to the yarn (2) so that the signal frequency can be used as a measurement of the twist in a yarn (2) under test or as a feedback signal controlling the rate of twist imparted by a twist insertion station(8) during the formation of a yarn.

Abstract: An analysis system for a scanning electron microscope having a backscattered electron detector. The output of the detector is amplified, processed by an analogue to digital converter, multi-channel analyser, and digital conversion and processing circuit to generate a signal indicative of the atomic number factor of the specimen. Calculation of stoichiometric valence combinations of non-elemental specimens is also disclosed. A calibration device is also disclosed.

Abstract: A method and means of transmitting sunlight into the interior of a building by use of a planar solid transparent light deflecting panel or plate which is formed of a plurality of parallel identically spaced apart triangular ribs on one face, with the panel in its vertical orientation, the top slope angle (.gamma.) of each triangular rib, the bottom slope angle (.beta.) of each triangular rib and the included angle (.beta.+.gamma.

Abstract: An auxological measuring apparatus in which there is provided a flat surface which is preferably horizontal, having on it a plate arranged for contact by the feet of a person with his back against the surface and on the case of a horizontal surface lying supine on it, there being a carriage linearly moveable on the surface which can be brought into contact with the person's head. An electronic transducer is associated with the carriage and is arranged to produce an electric signal indicative of the distance between the carriage and the surface and it is associated with electronic circuitry arranged to process the signal and to provide a visible indication of the distance and thus of the height of the person on the surface. A side table may be provided for attachment to the surface so that a person may lie on the surface and the side table with arms outstretched on the table so that an arm span mesurement can be made.

Abstract: A self-balancing DC-substitution measuring system includes a temperature dependant resistor (TDR) which is placed in one leg of a Wheatstone Bridge circuit, diagonally opposed first and second nodes of the bridge being driven respectively by the outputs of two operational amplifiers such that the potential at each of these first and second nodes, when measured with respect to a common reference point is equal in magnitude and opposite in polarity to the other. Each of the amplifiers has a pair of differential inputs and each of these inputs are connected to either of the remaining third and fourth nodes of the bridge circuit or to the common reference point, no two inputs from the same amplifier being connected to the same point and each of the third and fourth nodes and the common reference point having at least one amplifier input connected to it.

Abstract: The present invention relates to a feedforward-error-correction amplifier system comprising a switching circuit, a linear-amplification means, and a summing network, wherein an amplifier-system input signal is connected to a first input port of the linear-amplification means, and an output voltage signal produced at an output port of the linear-amplification means is fed to a first input port of the summing network, a signal which is a function of a current flowing in the output port of the linear-amplification means is fed to an input port of said switching circuit, said switching circuit having an output port at which a switching output signal is produced and which switching output signal is fed to another input port of the summing network, an output current flowing in the output port of the switching circuit having a time rate of change limited by a low-pass-filter means, a sensing signal which is a function of the switching output signal being fed to another input port of the linear-amplification means, t