Abstract: A sintered body of silicon nitride with high density, strength, toughness, and hardness, which can be used for a structural part of an engine, etc. The sintered body of the invention includes 80 to 94 wt % Si.sub.3 N.sub.4, 2 to 10 wt % Mg compound calculated in MgO equivlent, and 2 to 10 wt % Y compound calculated in Y.sub.2 O.sub.3 equivalent. The Si.sub.3 N.sub.4 contains 5 to 40% .alpha.-phase. The sintered body is manufactured in the following steps: (a) mixing powdery Si.sub.3 N.sub.4 with a Mg compound and a Y compound in the above proportions, and then molding the mixture in which the Si.sub.3 N.sub.4 powder contains 80% or more .alpha.-phase and its grains are 1 .mu.m or less in diameter on average; (b) performing primary sintering at 1,600.degree. C. or less in an atmospher of nitrogen or of an inert gas at 20 atm or less; and (c) performing secondary sintering at 1,400.degree. to 1,600.degree. C. in an atmosphere of nitrogen or of an inert gas at 300 atm or more.

Abstract: A sintered silicon nitride product comprises from 72 to 98% by weight of silicon nitride, from 1 to 8% by weight of vanadium pentoxide, and from 1 to 20% by weight of one or more oxides of rare earth elements. The vanadium pentoxide and the oxide of rare earth elements accelerate the densification of the sintered product, and provide high strength at high temperature as well as excellent oxidation resistance to the sintered product.

Abstract: A spread spectrum communication system having a modulation unit for modulating and spreading an information signal by one or more of carrier signals and a spread code and transmitting it as a radio wave, and a demodulation unit for despreading and demodulating a received radio wave to pick up the information signal. The modulation unit includes a synthesizing and modulating unit for synthesizing a first primary modulated signal obtained by modulating a first carrier by the information signal and a second primary modulation signal obtained by modulating a second carrier, and a spectrum spreading unit for spreading the synthesized first and second primary modulation signals with a spread code to generate a spread spectrum signal containing first and second spread signal components.

Abstract: A duplex data processing system includes two processors each provided with a bus connecting unit which disconnects the associated CPU bus from the cross connection bus in a separate mode or connects the CPU bus to the cross connection bus in a duplex mode. The system operates with a logically unified CPU bus through the connection of the internal CPU buses by the two bus connecting units in both processors.

Abstract: Disclosed is a heat-resistant flame-retardant epoxy resin composition comprising a halogen-containing epoxy resin obtained by reacting a trifunctional epoxy compound having a specific structure with a halogenated bisphenol in the presence of a catalyst. Furthermore, a novel specific trifunctional epoxy compound is disclosed, which is valuably used for the production of the above-mentioned halogen-containing epoxy resin.

Abstract: A triphenol type compound represented by the following formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 independently represent hydrogen, a halogen, a C.sub.1 -C.sub.5 alkyl group or a C.sub.1 -C.sub.5 alkoxy group.The triphenol type compound can be used, as a branching agent, for the production of a polycarbonate comprising (A) a carbonic acid component unit, (B) a divalent phenol component unit, and (C) a triphenol type compound component unit derived from the above-mentioned triphenol type compound. The triphenol type compound unit (C) is used in an amount of 0.01 to 10 mole %, based on the divalent phenol component unit (B) and the intrinsic viscosity [.eta.], determined at 25.degree. C. in methylene chloride, of the polycarbonate is 0.4 to 1.0 dl/g and the glass transition temperature (Tg), determined by a differential scanning type calorimeter is 150.degree. C. to 300.degree. C.

Abstract: A process for the production of aromatic carboxylic acid in a continuous manner by oxidizing an alkyl aromatic compound in the liquid phase with an oxygen-containing gas in the presence of heavy metal compound(s) and/or bromine-containing compound, which process is characterized by that a part of the reaction gas delivered from the reactor and freed from the condensing components is recirculated by returning it to the reactor at a portion within the gas region. Said process permits to produce aromatic carboxylic acids of high quality, while eliminating the troubles due to foaming occurring on the liquid surface in the reactor.

Abstract: A triphenol type compound represented by the following formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 independently represent hydrogen, a halogen, a C.sub.1 -C.sub.5 alkyl group or a C.sub.1 -C.sub.5 alkoxy group.The triphenol type compound can be used, as a branching agent for the production of a polycarbonate comprising (A) a carbonic acid component unit, (B) a divalent phenol component unit, and (C) a tripenol type compound component unit derived from the above-mentioned triphenol type compound. The triphenol type compound unit (C) is used in an amount of 0.01 to 10 mole %, based on the divalent phenol component unit (B) and the intrinsic viscosity [.eta.], determined at 25.degree. C. in methylene chloride, of the polycarbonate is 0.4 to 1.0 dl/g and the glass transition temperature (Tg), determined by a differential scanning type calorimeter is 150.degree. C. to 300.degree. C.

Abstract: A plurality of ceramic green sheets each provided with electrodes are prepared and laminated to form a laminated unit. The laminated unit is then vacuum packed in a rubber covering or a synthetic resin sheet. The vacuum packed laminated unit is pressed by hydrostatic pressure within a high-pressure vessel, whereby the plurality of ceramic green sheets are pressed to form a single ceramic sheet, which is then baked to form a chip.

Abstract: A device for fixing by suction a printing plate comprises: a casing whose interior is partitioned into a large number of compartments having open front faces; a perforated punching plate fixed to the casing to cover the open front faces of all compartments; a valve device mounted on a valve port formed on the rear side of each compartment; and a negative pressure source connected by way of the valve ports to respective compartments and applying suction to all valve devices, whereby the printing plate placed on the punching plate is fixed by suction tightly thereagainst.

Abstract: Disclosed is a process for the preparation of phenols which comprises reacting an .alpha.-hydroxyalkyl-substituted aromatic compound and/or an .alpha.,.beta.-unsaturated alkyl-substituted aromatic compound with hydrogen peroxide in the presence of an acid catalyst, in which hydrogen peroxide is diluted with a diluent, especially acetone, so that the volume is at least 10 times the original volume, and the diluted hydrogen peroxide is supplied in a divided manner to at least two portions of a reaction vessel or the diluted hydrogen peroxide is scattered by sprinkling into the reaction vessel. According to a preferred embodiment, the diluted hydrogen peroxide is continuously supplied to the gas phase in the reaction vessel from a scattering device which is similar to but separate from a scattering device for supplying the starting aromatic compound, particularly, a product formed by oxidizing an isopropyl aromatic compound with molecular oxygen.

Abstract: A process for the preparation of peroxides by condensation reaction of a tertiary organic hydroperoxide with a tertiary alcohol, which is characterized in that zinc chloride is present as a catalyst in an amount of at least 1% by weight based on the tertiary alcohol, is disclosed. This process can be advantageously applied to continuous manufacture of peroxides, and according to this process, peroxides can be obtained in high yields.

Abstract: A liquid peroxide composition comprising dicumyl peroxide and a dicumyl peroxide derivative having one nucleus substituted by an alkyl group having 1 to 3 carbon atoms is disclosed. This peroxide composition can easily be handled because it is liquid, and it is very valuable as a cross-linking agent for an olefin polymer or a synthetic rubber.

Abstract: There is provided a data transfer system for use in a data processing system. The data processing system comprises a central processor for processing information in accordance with an instruction stored in a main memory equipment, a peripheral equipment operable by receiving the instruction from the central processor and transmitting to the central processor a control information which requires the central processor to effect successive controlling operation, and an address bus, data bus and execution bus connecting the central processor to the peripheral equipment. When transferring data from the central processor to the peripheral equipment, the operating sequence procedure of the central processor is changed in accordance with the content on the status bus through which the control information from the peripheral equipment is transmitted to the central processor, whereby a sequence commensurate with the status of the peripheral equipment in operation is effected within the same instruction.