Abstract: A method for producing a high-porosity vitrified grinding stone that has a plurality of pores communicating with each other. The method includes: (a) a grinding-stone-material preparing step of obtaining a grinding-stone raw material slurry that is a mixture fluid of abrasive grains, a vitrified bond, a gellable water-soluble polymer and a water; (b) a molding step of obtaining a molded body, by gelling the grinding-stone raw material slurry with use of a molding mold; (c) a freeze vacuum drying step of generating a plurality of frozen particles inside the molded body by freezing the molded body, and placing the molded body under a vacuum state, so as to sublimate the frozen particles generated inside the molded body for thereby drying the molded body; and (d) a firing step of obtaining the high-porosity vitrified grinding stone, by binding the abrasive grains with the vitrified bond by firing the molded body.

Abstract: In a high-porosity CBN vitrified grinding stone having a homogeneous structure, a CBN abrasive grain, a large-diameter inorganic hollow filler having an average particle diameter in a range from a grain size one class coarser to a grain size one class finer with respect to a class indicating a grain size of the CBN abrasive grain, and a small-diameter inorganic hollow filler having an average particle diameter of ? to ½ of that of the CBN abrasive grain are bonded by an inorganic bonding agent.

Abstract: In a high-porosity CBN vitrified grinding stone having a homogeneous structure, a CBN abrasive grain, a large-diameter inorganic hollow filler having an average particle diameter in a range from a grain size one class coarser to a grain size one class finer with respect to a class indicating a grain size of the CBN abrasive grain, and a small-diameter inorganic hollow filler having an average particle diameter of ? to ½ of that of the CBN abrasive grain are bonded by an inorganic bonding agent.

Abstract: A semiconductor module includes: a semiconductor package in which a semiconductor device is incorporated; a snubber circuit having a snubber capacitor and a snubber resistor which are connected in parallel to the semiconductor device; a first light-emitting device emitting light when residual voltage between an anode and a cathode of the semiconductor device becomes equal to or higher than first voltage; and a second light-emitting device emitting light when the residual voltage becomes equal to or higher than second voltage, wherein the first and second voltages are different from each other.

Abstract: A semiconductor module includes: a semiconductor package in which a semiconductor device is incorporated; a snubber circuit having a snubber capacitor and a snubber resistor which are connected in parallel to the semiconductor device; a first light-emitting device emitting light when residual voltage between an anode and a cathode of the semiconductor device becomes equal to or higher than first voltage; and a second light-emitting device emitting light when the residual voltage becomes equal to or higher than second voltage, wherein the first and second voltages are different from each other.

Abstract: A vitrified superabrasive grain grinding stone includes superabrasive grains including a CBN abrasive grain as a main abrasive grain and a diamond abrasive grain as an auxiliary abrasive grain bonded together by use of a vitrified bond. The auxiliary abrasive grain has an average grain diameter equal to ½ to 1/10 of that of the main abrasive grain, and the auxiliary abrasive grain has a toughness value of 0.4 to 1 when that of the main abrasive grain is given as 1.

Abstract: A vitrified superabrasive grain grinding stone includes superabrasive grains including a CBN abrasive grain as a main abrasive grain and a diamond abrasive grain as an auxiliary abrasive grain bonded together by use of a vitrified bond. The auxiliary abrasive grain has an average grain diameter equal to ½ to 1/10 of that of the main abrasive grain, and the auxiliary abrasive grain has a toughness value of 0.4 to 1 when that of the main abrasive grain is given as 1.

Abstract: A data transfer apparatus and method uses recovery-type congestion control and avoidance-type congestion control. A bandwidth determination unit determines a requested bandwidth for a congestion avoidance-type data transfer in accordance with control information communicated between applications prior to the congestion avoidance-type data transfer. A bandwidth estimation unit estimates a bandwidth having been used by a congestion recovery-type data transfer in accordance with the control information communicated between applications prior to the congestion recovery-type data transfer. A management information memory stores information data of all the congestion avoidance-type data transfers and congestion recovery-type data transfers that use the bandwidth at a particular moment (i.e., simultaneously).

Abstract: An overlay cellular communication network, which includes a first base station for providing a first cellular communication network having a first cell size, and a second base station for providing a second cellular communication network which covers the first cellular communication network and has a second cell size, is provided to determine a proper transmission route immediately and to cover a broad area communication network with certainty.A mobile station belonging to an overlay communication network, which includes a micro cell having a first cell size and a macro cell having a second cell size, has an mobile station identification address in the application layer defined by the OSI reference model, and also has a plurality of addresses, each of the plurality of addresses belonging to one of the data link layer through the presentation layer defined by the OSI reference model, which represent routes to reach the mobile station.

Abstract: The invention provides a light source for optical communication. The light source includes a spontaneous emission generator, an optical wavelength band narrower, an optical modulator, and an optical amplifier. The spontaneous emission generator generates non-coherent light which is band narrowed, modulated and amplified for a wireless optical communication in free space. The invention avoids a health hazard in respect of human eyes and remove a noise based on a spontaneous emission generated from an optical amplifier.

Abstract: A contention control system unitarily manages a plurality of data transmissions so as to avoid contention therebetween. Data transmission command sending equipment of a data receiver continuously sends data transmission commands to a data sender according to a data transmission request. Data transmission-command receive control equipment receives the first valid one of the continuously-delivered data transmission commands therein and delivers it to data transmission control equipment. Correspondingly, data sending equipment starts to transmit data. Data transmission monitoring equipment of the data receiver monitors the state of transmission of the data.

Abstract: A phenolic resin obtained by reacting a phenol with an aromatic aldehyde and a xylylene compound represented by the formulaROH.sub.2 C(C.sub.6 H.sub.4)CH.sub.2 ORwhere R is hydrogen, an alkyl group having a carbon atom number of 1-4, or an acyl group having a carbon atom number of 2-4 in the presence of acid catalyst, with the sum of aromatic aldehydes and xylylene compounds to phenols molar ratio being 0.1-0.95, and the xylylene compounds to aromatic aldehydes molar ratio being 0.1-1.4.The phenolic resin thus obtained is useful as an industrial material by virtue of its excellent moisture resisting property, alkali resistance and fair thermosetting property. Having low moisture absorption ratio and high glass transition temperature, this phenolic resin is also suitable used as hardener for semiconductor encapsulating epoxy resin which has excellent package crack resistance after solder dipping and high reliability.

Abstract: A manual cleaner has a case, a roller brush having driven rollers and mounted between the side plates of the case, wheels kept in contact with the driven rollers and mounted on axles extending in parallel with the roller bruch, and dust pans provided at both sides of the roller brush. The dust pans are formed at both sides with bearing projections rotatably received in the side plates of the case so as to be pivotable about the projections. The projections are each formed with an axle receiving hole elongated horizontally so that the axles received in the holes can move toward and away from the roller brush. Thus the wheels can move toward and away from the driven rollers while keeping the dust pans in a stationary position. The shaft of the roller brush has both ends vertically movably mounted in bearing plates provided at both sides of the case and biased by springs downwardly. Spring members integrally formed on the bearing plates extend in opposite directions to abut and urge the dust pans closed.