Abstract: A superlattice avalanche photodiode with a mesa structure is provided, which enables to keep its noise characteristic low for a long time without decreasing the dynamic range for high-speed response. The photodiode has a semiconductor superlattice carrier multiplication layer, a first semiconductor electric-field buffer layers of a first conductivity type formed on one side of the carrier multiplication layer, and a second semiconductor electric-field buffer layer of a second conductivity type formed on the other side of the carrier multiplication layer. The photodiode further has a semiconductor light-absorbing layer of the second conductivity type formed on the second electric-field buffer layer. At least the light-absorbing layer constitutes the mesa structure. The first electric-field buffer layer is made of a central part and a peripheral part surrounding the central part. The peripheral part has a greater electric-field relaxation effect than that of the central part.

Abstract: In an oxygen gas sensor having a variable electrical characteristic dependent upon ambient oxygen concentration, a ceramic holding member having a hole for holding a plate sensor sensor element is disposed in a housing with the element inserted into the housing. During sensor assembly, powder is filled under pressure in the housing between a pressurized member and the ceramic holding member. The ceramic holding member has an inclined surface descending directly from an upper opening end of the holding hole to form an obtuse angle between the sensor element and the inclined surface, so that the powder can flow on the inclined surface smoothly during the powder filling and powder compressing operations. By taking this construction it is possible to provide an oxygen concentration sensor with no cracking of the element and easy mounting of the sensor element to the housing.

Abstract: In accordance with the present invention, there is provided a soldering process comprising the steps of: providing in a furnace first and second heaters each adapted to emit infrared energy; setting a printed circuit board, which has a solder paste and an electronic component thereon, in the furnace; heating the printed circuit board with the first heater; and heating the electronic component with the second heater;wherein the first and second heaters have different radiation spectra such that infrared energy irradiated by the first heater is more absorbed by the printed circuit board and less absorbed by the electronic component than that irradiated by the second heater. The present invention also provides a soldering apparatus for use in such soldering process.

Abstract: A toner supply control system of the electrophotographic apparatus which includes a developing unit 3 for developing with a developer composed of toner and carrier; a toner hopper 4 for storing the toner; a toner empty sensor 7 for detecting the remainder of toner in the toner hopper 4; and a toner supply drive unit 5 for conveying toner from the outside of the apparatus into the toner hopper 4. Toner is conveyed from the outside into the toner hopper 4 by driving the toner supply drive unit 5 over a predetermined period of time without stopping the operation of the electrophotographic apparatus when the toner empty sensor 7 detects over a predetermined period of time that the remainder of toner in the toner hopper 4 is small.

Abstract: A vibration damping device for mounting between two spaced portions of a vehicle. An inner metal cylindrical housing forms an internal piston chamber and is connected at one end to the vehicle, with a piston which is slidably mounted within the piston chamber, being connected to another portion of the vehicle. An outer housing surrounds a portion of the inner housing and forms a fluid duct or flow channel between fluid chambers formed on opposite sides of the piston. An electrode is mounted in the fluid duct for applying a voltage across the duct to affect the viscosity of an electrorheological (ER) fluid flowing therethrough to increase the damping force of the device. The electrode includes a plurality of circumferentially spaced splines and intervening grooves extending longitudinally along the fluid duct. The bottom portions of the grooves have a decreased electric field applied thereto than do the splines, providing bleed grooves or leak paths for the ER fluid to decrease the shear-rate of the fluid.

Abstract: When a developing agent prepared to have a preset toner density is loaded in a developing unit, a comparing reference level for controlling the toner density in the developing agent is changed to a value higher than the preset value in the initial stage of operation and fresh toner is supplied to the developing agent so that the toner density of the developing agent is increased in comparison to the reference level. Thereby, the developed density is prevented from decreasing due to an excess amount of friction charge of the toner.

Abstract: An electrophotographic apparatus system or an electrophotographic apparatus provided according to the present invention has the discrepancy of printing speed between tandem and single printing removed. The electrophotographic apparatus system or the electrophotographic apparatus is provided with printing speed changeover means 23a, 23b, 24 not only to select a printing speed applicable for the case where printing is effected with a plurality of electrophotographic apparatus A, B operatively linked together and another printing speed serviceable for the case where printing is implemented with each of plural electrophotographic apparatus put into separate run independently of one another, but also to shift the printing speeds from one to another, whereby the electrophotographic apparatus system or the electrophotographic apparatus may provide normal performance in each of the respective formations of printing.

Abstract: A semiconductor device according to the invention includes an electric field buffer layer, a superlattice multiplication layer and a cap layer, which are laminated. Around a mesa side surface, a round shape p.sup.+ dopant to a depth below the field buffer layer, and then the cap layer is etched so that the p.sup.+ region is not in contact with the cap layer. This creates a distance of several .mu.m in-between the inner surface of the p.sup.+ region and the external surface of the cap layer.

Abstract: A magneto-optic recording system uses a unit recording medium having on a substrate a first magnetic layer whose Curie temperature is low and also having on the first magnetic layer a second magnetic layer whose Curie temperature is high. The system heats a spot on the medium with a heating device. The system may employ two such unit recording media, each having the second magnetic layer magnetized in one direction. The two unit recording media are superposed on each other and formed integrally so as to obtain a magneto-optic recording medium in which the amount of information recorded and the recording speed are doubled. In addition, a light-emitting device and a magnetic field generator are added to the magneto-optic recording medium to obtain a compact magneto-optic recording system with a low level of power consumption.

Abstract: A vibration damping device for mounting between two spaced portions of a vehicle for absorbing road forces exerted on the vehicle. An inner metal cylindrical housing forms an internal piston chamber and is connected at one end to one portion of the vehicle, with the outer end of the rod of a piston which is slidably mounted within the piston chamber, being connected to the other portion of the vehicle. An outer housing surrounds a portion of the inner housing and forms a fluid transfer duct between fluid chambers formed on opposite sides of the piston within the piston chamber. An electrode is mounted on an inner surface of the outer housing and is electrically isolated therefrom and communicates with the fluid transfer duct for applying a voltage across the duct to affect the viscosity of an electrorheological (ER) fluid flowing therethrough to increase the damping force of the device.

Abstract: A vibration damping device comprises two cylindrical and flexible membrane members liquid-tightly connected at its end portion to respective end portion of a piston member and at its other end portions to respective face plates, a connecting member connecting the face plates to each other to form a closed chamber, a liquid filled in the closed chamber, and fastening members arranged onto the piston member and face plate, respectively. Moreover, at least one restricted passage is formed in the piston member or the connecting member. When an electrorheological fluid is used as a liquid, electrodes are arranged on opposed walls of the restricted passage.

Abstract: A unit recording medium, having on a substrate a first magnetic layer whose Curie temperature is low and also having on the first magnetic layer a second magnetic layer whose Curie temperature is high, is heated by a heating device. After two such unit recording media each having the second magnetic layer magnetized in one direction are fabricated, and the fabricated two unit recording media are superposed on each other and formed integrally so as to obtain a magneto-optic recording recording medium in which the amount of information recorded and the recording speed are doubled. In addition, a light-emitting device and a magnetic field generator are added to the magneto-optic recording medium to obtain a compact magneto-optic recording system with a low level of power consumption.

Abstract: A vibration damping device comprises two cylindrical and flexible membrane members liquid-tightly connected at its end portion to respective end portion of a piston member and at its other end portions to respective face plates, a connecting member connecting the face plates to each other to form a closed chamber, a liquid filled in the closed chamber, and fastening members arranged onto the piston member and face plate, respectively. Moreover, at least one restricted passage is formed in the piston member or the connecting member. When an electrorheological fluid is used as a liquid, electrodes are arranged on opposed walls of the restricted passage.

Abstract: An optical disc recording apparatus which records data with a second rotation frequency on an optical disc containing a preliminarily written recording condition in relation to a first rotation frequency. The optical disc recording apparatus preliminarily possesses recording condition in relation to the first and second rotation frequencies. The optical disc recording apparatus initially reads the recording condition in relation to the first rotation frequency, and then, in accordance with the read-out recording condition in relation to the first rotation frequency and the stored recording condition in relation to the first and second rotation frequencies, the recording apparatus computes the recording condition applicable to the optical disc in relation to the second rotation frequency. Finally, the optical disc recording apparatus records data on the optical disc by applying the computed recording condition.

Abstract: A vibration damping device includes axially spaced first and second end members adapted to be mounted on spaced apart structures. An intermediate member is mounted within an open end of the second end member. A center member consisting of a rigid tube having a hollow bore and a lower piston is connected to the first end member and extends through the interior of the intermediate member. The tube forms an annular orifice which extends about a rigid electrode rod which extends through the rigid tube and which is also connected to the first end member and piston but electrically isolated therefrom. A pair of elastomeric sleeves extend between the intermediate member and first end member and between the intermediate member and the piston to form a pair of fluid chambers communicating with the orifice and adapted to contain an electrorheological fluid. Each of the sleeves has a rolling lobe with circular centers and different radii of curvature.

Abstract: A plug device for a liquid container is presented to enable cleaning of a flow passage of the liquid container as well as to eliminate the liquid being left in the flow passage during the operation of the liquid container, thus providing hygienic and safe operation of the container. The plug device consists of an outer plug member and an inner plug member which is detachably attached to the outer plug member. When the members are assembled, a flow passage is formed automatically to enable access to the liquid stored in the container. When a press button provided on the inner plug member is pressed down, the opening disposed at the bottom of a plunger device remains open, resulting in the interior space of the container being connected with the flow passage via the internal liquid passage. In this condition, the container can be tilted to dispense the liquid from the container.

Abstract: Disclosed herein are a refractory material of high-purity electrofused magnesia clinker having good resistance to corrosion by slag, especially the slag with a high iron content, at high temperatures under an oxidative environment, and a burned or unburned refractory brick made of such refractory material of high corrosion resistance, which is superior in corrosion resistance as well as spalling resistance.The refractory material comprises more than 10 wt. % of electrofused magnesia clinker containing 98.0 to 99.8 wt. % of MgO, less than 0.05 wt. % of SiO.sub.2, and 0.1 to 2.0 wt. % of CaO. It may be in the form of burned or unburned or prepared unshaped refractories.

Abstract: A magneto-optic recording medium has a cartridge provided with a magnetization direction indicating portion for indicating the direction of magnetization of a second magnetic layer. Alternatively, the direction of magnetization of the second magnetic layer is recorded in advance in the first magnetic layer. The direction of magnetization of the second magnetic layer indicated or recorded is detected and recognized. A magnetic field oriented in an opposite direction to the direction of magnetization detected is imparted to the magneto-optic recording medium. Alternatively, predetermined information is recorded in the first magnetic layer, the direction of magnetization of the second magnetic layer is detected on the basis of a signal reproducing that information, and the direction of a magnetic field to be applied to the magneto-optic recording medium is set on the basis of the direction of magnetization thus detected.

Abstract: A vibration damping device comprises two cylindrical and flexible membrane members, a restricted passage constituting member connected at both end portions to these membrane members, two face plates connected at their end portion to the membrane members, a closed chamber defined by these members and face plates, a rigid member connecting both the face plates to each other at inside or outside of the closed chamber, a fluid filled in the closed chamber, and a fastening member disposed at each side of the restricted passage constituting member and the face plate.

Abstract: A circuit board comprising a core material made from magnesium, a magnesium alloy, or a magnesium-based composite material, and an electric circuit formed on the core material. A process for producing the circuit board comprises the steps of (1) forming an electrodeposition-painted coating on such a core material, (2) forming a polyimide resin coating on the electrodeposition-painted coating, (3) forming a via hole extending through the resin coating to the underlying electrodeposition-painted coating, (4) etching and removing the electrodeposition-painted coating in the region exposed in the bottom of the via hole while masking the other region with the resin coating thereby extending the via hole to the core material, (5) forming a metal film on at least a free surface of the resin coating and an inner surface of the extended via hole, and (6) etching the metal film by using a photoresist mask to form a conductor layer having a predetermined pattern.