Showing papers by "Mitsubishi Electric published in 1989"

Multimedia data transmission system

Abstract: A vector quantizer which transmits the input vector of the time when the minimum distortion is larger than the preset distortion threshold value and stores such input vector into the second code book as the new quantizing representative vector for the use in the successive vector quantizing processes. Further, since the first and second code book constitute in the form of tree-structure, calculation for search may be executed at a high speed.

Double gate static induction thyristor

Abstract: A double gate static induction thyristor comprises a semiconductor substrate, a first gate region formed at a first principal surface of the substrate, and a first semiconductor region of a first conduction type formed on the same first principal surface. A second gate region is formed at a second principal surface of the substrate, and a second semiconductor region of a second conduction type is formed on the same second principal surface. Gate electrodes are formed on the first and second gate regions, and main electrodes are formed on the first and second semiconductor regions, so that portions of the semiconductor regions surrounded by the gate regions form a current path between the main electrodes. Further, impurity is deeply diffused in portions of the first and second gate regions formed with the gate electrodes.

Portable communication device

Abstract: A portable radio device in which a radio telephone device body and a receiver unit are separately constructed and connected together by a pair of adjustable supporting rods As a result, the distance between the radio telephone device body and the receiver unit can be adjusted according to whether the device is being used as a telephone unit or a pager unit While being used as a telephone, the distance between a receiver and a microphone can be easily adjusted to the distance between an ear and a mouth of a user When the device is used as a pager, it can be miniaturized so as to be conveniently carried

Development of a guidance method for power system restoration

Abstract: A guidance method for restorative control that gives operators an appropriate restoration plan and restorative procedures is proposed. The approach combines the knowledge engineering technology with conventional programming. The resulting architecture gives various kinds of flexibility. It is possible to modify the restoration plan automatically if unexpected occurrences such as faults happen, and an operator's changes to the proposed plan are accepted. A prototype based on this model has shown very satisfactory results. >

Floor detector for vacuum cleaners

Abstract: A floor detector for a power brush of a vacuum cleaner comprises a lift sensor S1 and a floor sensor S2. The lift sensor S1 has a movable member which yieldably displaces when the power brush is placed on a relatively soft floor while the floor sensor S2 has a movable member which yieldably displaces when the power brush is placed on a relatively hard floor. Each of movable members is detected its movement by a corresponding light sensor which provides a signal representative of the movements. The signals from the light sensors are sent to a control circuit which controls a drive source for driving the brush member of the power brush. In this manner, the brush member is rotated when the power brush is placed on a relatively soft floor such as a carpeted floor and is not rotated when the power brush is placed on a relatively hard, flat, smooth floor.

GaAs/AlGaAs optical synaptic interconnection device for neural networks

Abstract: A GaAs/AlGaAs optical synaptic interconnection device for neural networks is reported for the first time to our knowledge. This device consists of a light-emitting-diode array, an interconnection matrix, and a photodiode array, which are integrated into a hybrid-layered structure on a GaAs substrate. The device structure and characteristics are reported in detail. The fabricated device can simulate a 32-neuron system. Experimental results of the Hopfield associative memory with three stored vectors are also described.

Phase-shifting transformer with a six-phase core

Abstract: A phase-shifting transformer including main and series transformer units comprises a six-phase core including six independent magnetic circuits, numbered first through sixth from right to left The combined U-, V-, and W-phase windings of the main transformer unit link with the fifth, third, and first magnetic circuits, respectively The combined a-, b-, and c-phase windings of the series transformer unit link with the sixth, fourth, and second magnetic circuits The winding directions of the V- and b-phase windings are reversed with respect to those of other phase windings Thus, if three-phase voltages 120 degrees apart are input to the main transformer unit, then the phase angles between the main magnetic fluxes generated in any two adjacent magnetic circuits are equal to 30 degrees Consequently, the magnitudes of the differential magnetic fluxes passing through the interphase portions between two adjacent magnetic circuits are reduced to about one half of the magnitudes of the main magnetic fluxes, with the result that the cross-sectional area of the interphase portions of the core can be reduced to about one half of that of its main leg portions

Load voltage detecting device for use in an apparatus for supplying a current variable with time to a load section

Abstract: A load voltage detecting device for use in an apparatus for supplying a current variable with time to a load section. The load voltage detecting device for an apparatus such as a pulsed are welding machine can accurately detect the load voltage from the output voltage of the pulse current supplying section without being affected by the reactor component and the resistance component of the load section and the elements extended to the load section such as the cables and the welding torch.

Scroll fluid machine

Abstract: The present invention provides a highly efficient and highly reliable scroll fluid machine that suppresses fluctuations in port aperture area during each revolution of an orbiting scroll while ensuring port aperture area. In the present scroll fluid machine, suction ports for sucking in a working fluid are disposed on a second base plate so as to have openings in a vicinity of a winding start end portion of a second spiral tooth, and near an inward facing surface of the second spiral tooth at a position that is separated by an involute angle of approximately 90° from the winding start end portion of the second spiral tooth. Discharge ports for discharging the working fluid are disposed on a first base plate so as to have openings in a vicinity of a winding start end portion of a first spiral tooth, and near an inward facing surface of the first spiral tooth at a position that is separated by an involute angle of approximately 90° from the winding start end portion of the first spiral tooth.

A copper/polyimide metal–base packaging technology

Abstract: A unique substrate MCPM (Mitsubishi Copper Polyimide Metal-base) technology has been developed by applying our basic copper/polyimide technology.1 This new substrate technology MCPM is suited for a high-density, multi-layer, multi-chip, high-power module/package, such as used for a computer. The new MCPM was processed using a copper metal base (110 × 110 mm), full copper system (all layers) with 50-µm fine lines. As for pad metallizations for the IC assembly, we evaluated both Ni/Au for chip and wire ICs and solder for TAB ICs. The total number of assembled ICs is 25. To improve the thermal dispersion, copper thermal vias are simultaneously formed by electro-plating. This thermal via is located between the IC chip and copper metal base, and promotes heat dispersion. We employed one large thermal via (4.5 mmO) and four small vias (1.0 mmO) for each IC pad. The effect of thermal vias and/or base metal is simulated by a computer analysis and compared with an alumina base substrate. The results show that the thermal vias are effective at lowering the temperature difference between the IC and base substrate, and also lowering the temperature rise of the IC chip. We also evaluated the substrate’s reliability by adhesion test, pressure cooker test, etc.

Numerical Simulations of Interaction between Stellar Wind and Interstellar Medium

Abstract: Hydrodynamic interaction between supersonic spherical wind emitted from an astronomical object and a uniform streaming flow is simulated numerically assuming the flow to be axisymmetric, adiabatic and inviscid. Examples of such a phenomenon are a comet in the solar wind, and the solar wind or a stellar wind in an interstellar medium. Three cases of the incident flow, i.e., subsonic, supersonic and hypersonic flow, are considered. Discontinuities in the flow, i.e., a bow shock, a contact surface, an inner shock, a Mach disc and a slip surface are identified. The contact surface and the slip surface are found to be Kelvin- Helmholtz unstable. Other instabilities occurring near the stagnation region and the inner shock are also found.

Surface Morphology and Crystal Structures of As-Grown BiSrCaCuO Thin Films Prepared by RF Magnetron Sputtering from Three Targets

Abstract: As-grown superconducting BiSrCaCuO thin films were grown at 650°C on MgO(100) substrates by RF magnetron sputtering from three targets. The substrate was rotated over the three targets: Bi3Sr2Ca2Cu3Ox, Bi2Sr3Ca3Cu3Ox and Bi2Sr2Ca2Cu4.5Ox. By adjusting the staying time of the substrate over each target, it was possible to precisely control the chemical composition of the thin film. This paper describes the superconducting properties, surface morphology and crystal structures of sputtered films formed by varying the staying time. X-ray diffraction measurement showed that the crystal structure could be changed by varying the staying time. The film with the optimum composition showed zero resistivity at 75 K and had an exceedingly smooth surface. This film had the mixed phase which is considered to be a stacked structure consisting of a high-Tc phase and a low-Tc phase.

Evaporation and decomposition of Triton X-100 under various gases and temperatures

Abstract: The thermal behaviour of Triton X-100 (surfactant in PTFE dispersion) under various gases was studied with differential scanning calorimetry (DSC) and IR spectrophotometry below 350° C. In nitrogen or argon gas, Triton X-100 evaporated without decomposition. However, in air or oxygen containing gas, thermal oxidation occurred, where a strong νco band appeared in IR spectra. Oxygen increased the evaporation rate of Triton X-100 remarkably. The heat of vaporization was about 16 kcal mol−1 which is independent of the oxygen concentration. The evaporation mechanism is discussed briefly.

Temperature dependence of the exciton population in emission spectra of GaAs single quantum wells with enlarged monolayer-flat growth islands

Abstract: The temperature dependence of the exciton population is investigated in GaAs single quantum wells (SQW) 19--22 monolayers wide with enlarged monolayer-flat growth islands grown by growth interrupted molecular-beam epitaxy. A comparative study with in-plane photocurrent spectroscopy shows that free-excitonic recombinations within the growth islands dominate the emission spectra even at room temperature. Detailed studies of the lowest heavy-hole exciton spectral characteristics as a function of the lattice temperature allow us to directly find the in-plane exciton localization and exciton detrapping processes between the SQW growth islands. A simple model analysis was made to explain observed temperature-dependent variations of the population at the exciton bands corresponding to the four different SQW growth islands, assuming Gaussian line-shape functions.

Tunnel unit and scanning head for scanning tunneling microscope

Abstract: A tunnel unit for a scanning tunneling microscope comprises a specimen stage 120 having a plurality of pole pieces 122 joined together via a joint member 123 formed of a non-magnetic material and a specimen placing surface 120a where the pole pieces and the joint member are exposed, a permanent magnet 121 rotatably inserted within the specimen stage and at the joint of the plurality of pole pieces, a scanning head main body 111, which is provided with a piezoelectric element 113 fixed thereto and a probe 115 mounted on the piezoelectric element, being disposed above the specimen placing surface of the specimen stage and extending across the exposed joint member, and three screws 112 formed of a magnetic material and turnably mounted on the scanning head main body, the screws having their end portions in contact with the specimen placing surface of the specimen stage such as to support the scanning head main body above the specimen placing surface.

Fiber Orientation Control of Short Fiber Composites: Experiment

Abstract: Orientation control of short fibers in a liquid matrix has been carried out by loading a magnetic field. Nickel coated graphite short fiber was used as a magnetic inductive fiber. From a practical point of view, main attention was placed upon the determination of the critical volume fraction of the fibers Vfc , which was the maximum value at which the ori entation control was possible. Vfc was experimentally shown to increase rapidly with decrease of aspect ratio of the fibers. Then, in order to force the increase of Vfc , ultrasonic vibration combined with the magnetic moment was loaded to loosen tangled fibers. The loading of the ultrasonic vibration had a remarkable effect in raising the Vfc .

Perpendicular transport of photoexcited electrons and holes in GaAs/AlAs short-period superlattices: Barrier-thickness and temperature dependence.

Abstract: Perpendicular transport of photoexcited carriers, which sink into an intentionally enlarged quantum well, is investigated in a set of GaAslAlAs short-period superlattices with systematically varied AlAs barrier thicknesses as a function of the lattice temperature between 4.2 and 200 K. Excitation-power dependence of the luminescence observed at low temperatures indicates that the ambipolar transport is operative at carrier densities in excess of 1015_1017 cm3• We find that tunneling-assisted hopping conduction prevails at low temperatures via localized states and that the tunneling probability is correlated with the calculated heavy-hole miniband width. We also find a crossover from the hopping conduction to the Bloch-type transport at higher temperatures, which critically depends on the barrier thickness, as a result of thermal activation of carriers to the extended miniband states.

Magnetic field-assisted polishing — application to a curved surface

Abstract: Magnetic field-assisted polishing using a magnetic fluid was applied to a curved surface. As a polishing test material, a single crystal of LiNBO3, a hard and brittle material, was examined; it was previously machined to a spherical surface by diamond turning. The results of polishing experiments show that surface roughness of 0.01 μm R max can be easily obtained by this method. It is also clarified that the magnetic field intensity is closely related to the polishing pressure and the removal rate. Therefore, to finish curved surfaces precisely, the magnetic field distribution must be kept uniform.

Motion detecting circuit for video signal processing using correlation techniques

Abstract: A motion detecting circuit is used for a motion-adapted scanning line interpolating circuit in a television system. The motion detecting circuit comprises an inter-frame correlation detecting circuit for detecting and outputting the value of correlation of video signals between adjacent frames, an inter-field correlation detecting circuit for detecting and outputting the value of correlation of signals of corresponding pixels between adjacent fields and an adjusting circuit for adjusting the output of the inter-frame correlation detecting circuit in accordance with the correlation value outputted from the inter-field correlation detecting circuit. An interlace/non-interlace signal converting circuit is also provided with the motion detecting circuit.

Three phase parallel processing UPS using multi-functional inverter

Abstract: A parallel processing uninterruptible power supply (UPS) system is proposed in which a three-phase pulse-width modulation (PWM) inverter is connected in parallel to a utility power source through an inductance and an electronic switch. In this system, when the utility power is on, the inverter controls the voltage regulation of the inductance so as to control the output voltage constantly in synchronization with the utility. The batteries are charged by the inverter at the same time. The inverter also absorbs the load harmonics so as to obtain a sinusoidal output voltage. When a power failure happens, the electronic switch in the input line is turned off and the inverter operates alone with no break of power supply to the load. Using only one inverter, the parallel processing UPS realizes a combined system of a constant voltage power source, an uninterruptible power supply, and a harmonics absorbing active filter. This system can also link new types of DC power sources, such as fuel cells or photovoltaic cells, to utility power systems. >