Abstract: An X-ray apparatus comprises a polychromatic X-ray source for generating a primary beam of small cross-section, an energy-sensitive detector arrangement for detecting the scattered radiation produced by elastic scattering processes in the primary beam, which detector arrangement comprises a plurality of detector elements which are arranged on rings concentric with the primary beam, and a collimator arrangement which is arranged between the X-ray source and the detector arrangement and which encloses the primary beam. In order to enable accurate determination of the pulse transfer spectrum while using a low dose, the collimator arrangement is constructed so that the scattered radiation from the same section of the primary beam is incident on a plurality of detector elements.

Abstract: The transfer gate between the master section and the slave section in a flip-flop circuit includes a circuit for reducing the sensitivity to slow clock edges and clock skew. This is accomplished by prolonging the transfer time for data from the master to the salve section of the flip-flop circuit.

Abstract: A circuit which responds to the application of a pulse to its input (6) by generating a pulse at its output (3), the output pulse having a minimum duration T and being extended by the remaining length of the input pulse should the input pulse be still present at the end of the time T, comprises a pair of semiconductor switches (1,2) connecting the output (3) to points (5,4) carrying respective logic levels. The input pulse closes the first switch (1) and also inhibits a gate circuit (9). The resulting logic level on the output (3) closes the second switch (2) after delay by T in a delay circuit (13) and transmission through the gate circuit (9), thereby restoring the original logic level. The instant when this occurs coincides with the presence of the delayed output pulse at the output (14) of the delay circuit and the absence of the pulse at the arrangement input (6). A hold circuit circuit (15) may be provided for holding the logic level currently present at the output (3).

Abstract: A lithotripsy workstation, comprises a patient supporting device (1), a shockwave source (4) for generating shockwaves which are focused onto a point (focus) (6) fixed in space, an X-ray source (10) which irradiates the focus (6) from at least two defined positions, and an image detector (12) which detects the X-ray image produced by the X-ray source (10). The cost and the weight of the workstation can be reduced in that a marker (16) which can be displayed in the X-ray image is secured to the X-ray source (10), which marker is situated, at least in the two positions, on the connecting line between the focal spot (11) of the X-ray source (10) and the focus (6).

Abstract: In magnetic resonance imaging various error sources lead to deterioration of the image quality. One class of errors is formed by errors which vary only slowly over the time required to sample a data line but vary substantially over the time required to acquire data for the complete magnetic resonance image. These error sources are, for example external magnetic fields, motion due to respiration, drift in amplifiers or drift phenomena in permanent magnets due to temperature influences. It is proposed to utilize mutually intersecting data lines in the Fourier domain so as to estimate these error sources and to use these estimates to correct the data sets obtained before execution of image reconstruction.

Abstract: A transferred electron effect device has a semiconductor body with an active region (2) of n conductivity type formed of a semiconductor material having a relatively low mass, high mobility conduction band main minimum and at least one relatively high mass, low mobility conduction band satellite minimum, and an injection zone (3) adjoining the active region (2) for causing electrons to be emitted, under the influence of an applied electric field, from the injection zone (3) into the active region (2) with an energy comparable to that of the relatively high mass, low mobility, conduction band satellite minima of the active region.

Abstract: A switching network for an asynchronous time-division multiplex transmission system includes a first stage having a plurality of switching blocks (4 to 7), to which are applied over auxiliary lines cells and routing information intended for various trunk lines and which are coupled to at least one switching block (8, 9) of a second stage. Inputs of switching blocks (4 to 7) of the first stage are coupled to auxiliary lines and at least one output of a switching block (8, 9) of the second stage. Outputs of switching blocks of the first stage are coupled to trunk lines and to at least one input of a switching block of the second stage. A cell extraction circuit (56 to 61) which is always coupled to a control circuit (10 to 15) of the associated switching block is coupled either to at least one input or to at least one output of each switching block.

Abstract: A circuit arrangement for optionally amplifying one of two signals (from 2 or 6 respectively) in which at least one of the signals is supplied via a switchable signal path interruption which is inhibited when no signal is applied thereacross, and to which in this state a signal voltage is applied to both ends, which is associated with the signal to be amplified and which has already been amplified, respectively. When such a structure of a circuit arrangement is used, no damage to the circuit structure can occur, even when a signal path is interrupted in normal operation.

Abstract: An X-ray tube has a focal spot which can be varied in respect of position or size. A cathode has dimensions adapted to the variation of the focal spot, and between the cathode and the anode of the X-ray tube there is a grid arrangement which comprises a number of grid elements in one plane, which elements are electrically insulated from one another, and whose potential is independently controlled.

Abstract: A semiconductor body (1) defines at least one active device. In the example shown in FIG. 1 complementary n channel and p channel IGFETs (10 and 20) are provided. An electrically conductive region, which may form the gate conductive region (101 and 102) of the insulated gates (11 and 21) of an IGFET, is provided on a first major surface (2) of the semiconductor body (1) and is encapsulated within a covering insulating region (300,400). An area (100a) of the electrically conductive region (101 and 102) contacts a relatively highly doped semiconductor region (50) provided adjacent the one major surface (2) and electrical contact is made to the electrically conductive region (101 and 102) via a conductive track (205) provided on the first major surface (2) and a conductive path provided by the relatively highly doped semiconductor region (50).

Abstract: The present invention relates to a vacuum arc electron source having an anode and a cathode facing each other such that they produce a plasma (P) after an appropriate voltage difference has been applied between the anode and the cathode, an electron extractor device (30) and a material-retaining device arranged between the extractor device and the plasma source. According to the invention, the material-retaining device comprises, arranged in the electron extraction direction (F), at least one upstream baffle (10) and a downstream baffle (20) which are each electrically conducting and have apertures (16, 26) arranged in quincunx, such that when the baffles (10, 20) are adjusted a given potential, the plasma (P) does not extend to downstream of the downstream baffle (20).

Abstract: In a device for doubling the frequency of a light wave, a fundamental light wave 2 originating from a laser light source 1 is guided through a nonlinear optical medium 5 while forming a second harmonic wave 6. The nonlinear optical medium is formed from a polymer network and elements having a great hyperpolarizability. In the device, phase matching is realised by the application of a polymer network having a helical structure. The pitch of the helical structure is adapted to the phase-matching conditions by the selection of the polymerization conditions during the formation of the network.

Abstract: Suitable starting materials for the manufacture of a heavy metal fluoride glass composition are mixed with solid xenon fluoride as the fluoridizing reagent, after which the mixture is heated to temperatures between 200.degree. and 400.degree. C. in an inert atmosphere for a time which suffices to bring about fluoridation of the starting materials. The intermediate product thus obtained is melted thereby forming a stable glass composition of a high purity and a high transparency. The method can be carried out in a simple manner in a furnace which need not be gastight.

Abstract: A first tool assembly includes a punch holder assembly and a circuit board clamp and a second tool assembly includes a die for receiving punches held and driven by the punch holder assembly. A circuit board has holes formed by the punches and is clamped by the clamp to the die. The circuit board and die are aligned to the punch assembly by an alignment pin secured to the punch assembly operated independently of the operation of the punch assembly. The punch assembly and the clamp are independently controlled by actuators with a convex distortion of the punch assembly and clamp during punching to provide an improved clamping and punching action.

Abstract: A pick-up and/or display device comprises a memory in which a video signal is written at a write frequency under the control of a clock and is read therefrom at a read frequency. Image expansion or image compression can thus be realized. The clock, a clock input of which is connected to a synchronizing pulse generator, comprises an oscillator having an adjustable frequency, an oscillator output constituting a clock output and being connected to a frequency divider whose output signal is applied to an integrating comparator circuit, an output signal variation of which is proportional to a difference between a mean input signal and a predetermined reference voltage, the comparator circuit being connected to a frequency set input of the oscillator, the oscillator comprising a trigger input which serves to switch the oscillator on and off and which constitutes the clock input.

Abstract: A method of manufacturing a semiconductor device includes forming field oxide regions (17) in a surface (1) of a silicon body (2) through oxidation, which body is provided with an oxidation mask (15) formed in a layered structure provided on the surface with a lower layer (4) of silicon oxide, an intermediate layer (5) of polycrystalline silicon and an upper layer (6) of a material including silicon nitride in which windows (8) are etched into the upper layer. The intermediate layer is etched away inside the windows and below an edge (10) of the windows, a cavity (11) is formed below the edge, and a material including silicon nitride is provided in the cavity. The material including silicon nitride is provided in the cavity while the surface of the silicon body situated inside the windows is still covered by a layer of silicon oxide, preferably with the lower layer of the layered structure.

Abstract: A semiconductor device is formed by a semiconductor body (1) having a substrate (2) on which is provided a channel-defining region (10) extending between input and output regions (20) and (21). The channel-defining region (10) has a channel layer (11) forming a heterojunction (12) with at least one barrier layer (13) to form within the channel layer (11) a two-dimensional free charge carrier gas (14) of one conductivity type for providing a conduction channel (14) controllable by a gate electrode (25). A potential well region (30) is provided between the substrate (2) and the channel-defining region (10).

Abstract: A shaving apparatus comprises a housing provided with a first shaving member having a first cutting edge and with a second shaving member having a second cutting edge, which second shaving member is drivable relative to the first shaving member, the movement of the second cutting edge relative to the first cutting edge in a plane transverse to the cutting edges being composed of the movements in two main directions in this plane. The second shaving member is provided with a carrier mounted in the housing so as to be movable in both main directions and the carrier comprises two surfaces which extend transversely of the main directions and which engage against a rotatably drivable cam disc.

Abstract: A device for detecting a centering error of a rotationally symmetrical surface (0.sub.1, 0.sub.2) of an object (0) with respect to a rotational axis (AR) about which axis the object is rotated for the purpose of the centering error detection is described. Two beams (b.sub.1, b.sub.2 ; b.sub.3, b.sub.4) at angles of approximately 90.degree. are directed onto the object and the variation in the phase difference caused by the centering error (.epsilon.) between the two beams (b.sub.1, b.sub.2 ; b.sub.3, b.sub.4) reflected by the surface is determined.