Abstract: A current collector positive electrode enabling a NaS battery to be excellent in the charge recovery characteristic and low in internal resistance is provided, which collector has a high resistance layer formed by needle-punching glass fibers with 5 to 15 ?m fiber diameter into a felt substrate made of carbon fibers or graphite fibers by needle-punching from one surface of the substrate toward another surface of the substrate. The density of the glass fibers needle-punched into the substrate is gradually decreased in the direction from the above mentioned surface to the other surface of the substrate, and the deepest portions of the needle-punched glass fibers reach the depths of 85 to 100% of the substrate thickness.

Abstract: The present invention provides a space-saving and low-cost emergency power system, which can be installed on a narrow place having limited space and employs a battery that is long in service life and low in frequency of replacement. This emergency power system comprises a circuit having a DC load, a rectifier, and a battery, which are electrically connected to one another. This circuit is adapted so that normally, DC power is supplied from the rectifier to the DC load, and the battery is charged, and that in an emergency, such as a power failure, in which an outage of the rectifier occurs, electric power is automatically supplied from the battery to the DC load. In this system, a sodium sulfur battery is employed as the battery.

Abstract: A current collector of positive electrode enabling a NaS battery to be excellent in the charge recovery characteristic and low in internal resistance is provided, which collector has a high resistance layer formed by needle-punching glass fibers with 5 to 15 &mgr;m fiber diameters into a felt substrate made of carbon fibers or graphite fibers by needle-punching from the one surface of the substrate. The density of the glass fibers needle-punched into the substrate is gradually decreased in the direction from the above mentioned surface to the other surface of the substrate, and the deepest portions of the needle-punched glass fibers reach the depths of 85 to 100% of the substrate thickness.

Abstract: The present invention provides a space-saving and low-cost emergency power system, which can be installed on a narrow place having limited space and employs a battery that is long in service life and low in frequency of replacement. This emergency power system comprises a circuit having a DC load, a rectifier, and a battery, which are electrically connected to one another. This circuit is adapted so that normally, DC power is supplied from the rectifier to the DC load, and the battery is charged, and that in an emergency, such as a power failure, in which an outage of the rectifier occurs, electric power is automatically supplied from the battery to the DC load. In this system, a sodium sulfur battery is employed as the battery.

Abstract: A ceramic cutting tool of a TiC-based sintered body containing 40 wt % or more of TiC, and 5 to 40 wt % of SiC whisker uniformly dispersed in the sintered body, said SiC whisker having a diameter of 0.2-1.5 .mu.m and a length of 1-20 .mu.m. The sintered body may include up to 40 wt % of Al.sub.2 O.sub.3, and may further contain sintering aid.Up to 40% by weight of TiC may be substituted with at least one of Ti, nitrides, oxides and borides of Ti, and solid-solution of said nitrides, oxides and borides of Ti to form a TiC-base composition.The TiC-base composition may be represented by (Ti.sub.a M.sub.b) (C.sub.c N.sub.d O.sub.e B.sub.f).sub.g where: M denotes at least one of transition metal elements of Groups IVa, Va and VIa, except Ti, according to the International Periodic Table; and a+b=1, 0<b.ltoreq.0.5, c+d+e+f=1, 0.5 .ltoreq.c.ltoreq.1.0, 0.ltoreq.d.ltoreq.0.5, 0.ltoreq.e.ltoreq.0.3, 0.ltoreq.f.ltoreq.0.5, 0.6.ltoreq.g.ltoreq.1.1.

Abstract: A ceramic cutting tool formed of a TiC-based sintered body contains 40 wt % or more of TiC, and 5 to 40 wt % of SiC whisker uniformly dispersed in the sintered body. The SiC whisker has a diameter of 0.2-1.5 .mu.m and a length of 1-20 .mu.m. The sintered body may contain up to 40 wt % of Al.sub.2 O.sub.3, and further sintering aids. Up to 40% by weight of the TiC may be substituted with at least one of Ti, nitrides, oxides and borides of Ti, and solid-solutions of these nitrides, oxides and borides of Ti to form a TiC-base composition. The TiC base composition may be represented by the formula (Ti.sub.a M.sub.b) (C.sub.c N.sub.d O.sub.e B.sub.f).sub.g, in which M denotes at least one transition metal element of Groups IVa, Va and VIa according to the International Periodic Table, except Ti; and a+b=1, 0<b.ltoreq.0.5, c+d+e+f=1; 0.5 c.ltoreq.1.0; 0.ltoreq.d.ltoreq.0.5; 0.ltoreq.e.ltoreq.0.3; 0.ltoreq.f.ltoreq.0.5; and 0.6.ltoreq.g.ltoreq.1.1.

Abstract: AlN-base sintered body with a high thermal caonductivity is produced by:preparing a compact of a material comprising 100 parts by weight of aluminum nitride and 0.1-10 parts by weight, calculated on metal element, of at least one component selected from the group consisting of elements of Groups 4a, 5a and 6a of the Periodic Table, and compounds thereof; andsintering said compact at a temperature ranging from 1500.degree. to 2000.degree. C. under a non-oxidizing atmosphere having a source of boron and/or carbon supply. The compounds include oxides, borides, nitrides and carbides. The elements include W, Mo, Ta and Ti. Oxides are converted to other compounds through sintering. This AlN-base sintered body has good wettability with metal for metallization and enables simultaneous sintering with metallization layer. Multilayer laminated circuit boards or substrates thereof can be produced.

Abstract: AlN-base sintered body with a high thermal conductivity is produced by:preparing a compact of a material comprising 100 parts by weight of aluminum nitride and 0.1-10 parts by weight, calculated on metal element, of at least one component selected from the group consisting of elements of Group 4a, 5a and 6a of the Periodic Table, and compounds thereof; andsintering said compact at a temperature ranging from 1500.degree. to 2000.degree. C. under a non-oxidizing atmosphere having a source of boron and/or carbon supply. The compounds include oxides, borides, nitrides and carbides. The elements include W, Mo, Ta and Ti. Oxides are converted to other compounds through sintering. This AlN-base sintered body has good wettability with metal for metallization and enables simultaneous sintering with metallization layer. Multilayer laminated circuit boards or substrates thereof can be produced.

Abstract: Whisker-reinforced ceramics with high fracture toughness and strength consists essentially of 5-40 weight % SiC including SiC whiskers, 1-30 weight % of at least one kind of oxides of elements selected from the group consisting of Al, Sc, Y and rare-earth elements, and the balance being silicon oxynitride constituents, wherein said SiC whiskers are present in an amount of no less than 5 weight % of the total essential constituents.The silicon oxynitride constituents are Si.sub.2 N.sub.2 O or a mixture of silicon nitride and silica (0.83-1.22 by molar ratio), or a mixture of Si.sub.2 N.sub.2 O and said mixture of silicon nitride and silica. Silicon oxynitride and SiC phases are predominant.

Abstract: A composite ceramic material reinforced with silicon carbide whiskers consists essentially of 5 to 45% by weight of SiC whiskers, 3 to 20% by weight of at least one selected from the group consisting of oxides and oxynitrides of zirconium calculated on zirconium, and the balance being a SiZlON-based ceramic substance. The SiAlON-based ceramic substance consists essentially of a substance selected from the group consisting of .beta.-SiAlON represented by a compositional formula of Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z (where 0<z.ltoreq.1) and an .alpha.,.beta.-composite SiAlON made up of said .beta.-SiAlON and an .alpha.-SiAlON of the formula M.sub.x (Si,Al).sub.12 (O,N).sub.16, where M denotes at least one selected from the group consisting of Li, Ca, Mg, Y and rare earth metals and 0<x.ltoreq.2; and 1 to 25% by weight of a glass phase containing therein Zr, Si, Al, O and N, or further at least one selected from the group consisting of Y, Mg, Ca and rare earth metals.

Abstract: A surface structure of A1N substrate comprising:an A1N substrate,an intermediate layer disposed on the A1N substrate, anda metallized layer disposed on said intermediate layer, said intermediate layer comprising at least aluminum, nitrogen and oxygen. The metallized layer has a main component of one of Mo-Mn alloy, Mo and W, and has a thickness of 1-20 .mu.m,This surface structure is produced by coating a surface of A1N substrate with metallizing layer components, heat treating the resultant coated substrate at a temperature of 200.degree.-500.degree. C. under an oxidizing atmosphere, and further heating the heat treated coated substrate at a temperature of 1200.degree.-1400.degree. C. under a nonoxidizing atmosphere having a dew point of -35.degree.to 5.degree. C.

Abstract: AlN-base sintered body with a high thermal conductivity is produced by:preparing a compact of a material comprising 100 parts by weight of aluminum nitride and 0.1-10 parts by weight, calculated on metal element, of at least one component selected from the group consisting of elements of Groups 4a, 5a and 6a of the Periodic Table, and compounds thereof; andsintering said compact at a temperature ranging from 1500.degree. to 2000.degree. C. under a non-oxidizing atmosphere having a source of boron and/or carbon supply. The compounds include oxides, borides, nitrides and carbides. The elements include W, Mo, Ta and Ti. Oxides are converted to other compounds through sintering. This AlN-base sintered body has good wettability with metal for metallization and enables simultaneous sintering with metallization layer. Multilayer laminated circuit boards or substrates thereof can be produced.

Abstract: A surface structure of AlN substrate comprising:an AlN substrate,an intermediate layer disposed on the AlN substrate, anda metallized layer disposed on said intermediate layer, said intermediate layer comprising at least aluminum, nitrogen and oxygen. The metallized layer has a main component of one of Mo-Mn alloy, MO and W, and has a thickness of 1-20 .mu.m.This surface structure is produced by coating a surface of AlN substrate with metallizing layer components, heat treating the resultant coated substrate at a temperature of 200.degree.-500.degree. C. under an oxidizing atmosphere, and further heating the heat treated coated substrate at a temperature of 1200.degree.-1400.degree. C. under a nonoxidizing atmosphere having a dew point of -35.degree. to 5.degree. C.

Abstract: A composite layer aluminum nitride-base sintered body has on at least one surface of AlN-base sintered body having a first layer and a second layer. The first layer is 100 parts by weight of at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof as a first component (s), and 0.1-50 parts by weight of AlN second component. The second layer has at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof. The thickness of said first layer is 0.5-40 .mu.m, and the sum of thickness of the first and second layers is 1-50 .mu.m. The AlN may also include sintering aids of oxides of rare earth metal and alkaline earth metals. Hydrides and oxides of Ti, Zr, Nb, V and Mn may be included in the first layer composition.

Abstract: A microwave absorber composed of dense silicon carbide having an electrical resistivity of one ohm-centimeter or more. In an electron linear accelerator, it is necessary to provide a microwave absorber to absorb excess energy used to accelerate electrons and discharge this excess energy in the form of heat in order for the accelerator to operate safely. The important characteristics are high-frequency wave absorption, good heat resistance, good thermal conductivity, and stability in a vacuum. The invention meets these requirements with a microwave absorber composed of dense silicon carbide. In an electron linear accelerator the absorber is attached to the end portion of an accelerator guide or a branch portion of a power divider to absorb unnecessary wave energy. Such a microwave absorber is found to have characteristics rendering it highly suitable for this application as well as others.

Abstract: A silicon carbide-graphite composite material is disclosed. The composite material includes graphite as a secondary phase which is segregated along the grain boundaries of all the silicon carbide grains. The graphite has an average grain size of not more than 3 .mu.m and is present in a proportion of 1 to 20 vol % based on the volume of the silicon carbide. The composite material has a density greater than 90% of the theoretical density. The composite material is a high density and high strength material.

Abstract: A composite layer aluminum nitride-base sintered body has on at least one surface of AlN-base sintered body having a first layer and a second layer. The first layer is 100 parts by weight of at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof as a first component(s), and 0.1-50 parts by weight of AlN second component. The second layer has at least one component selected from the group consisting of W, Mo, borides thereof and carbides thereof. The thickness of said first layer is 0.5-40 .mu.m, and the sum of thickness of the first and second layers is 1-50 .mu.m. The AlN may also include sintering aids of oxides of rare earth metal and alkaline earth metals. Hydrides and oxides of Ti, Zr, Nb, V and Mn may be included in the first layer composition.

Abstract: A silicon carbide-graphite composite material is disclosed. The composite material includes graphite as a secondary phase which are dispersed uniformly in a grain boundary of the silicon carbide. The graphite have an average grain size of not more than 3 .mu.m and are present in a proportion of 1 to 20 vol % based on the volume of the silicon carbide. The composite material has a density greater than 90% of the theoretical density. A process for producing the silicon carbide-graphite composite material is also disclosed. The composite material is a high-density and high-strength material.

Abstract: A process for producing a silicon carbide heating element is disclosed comprising: adding boron or a boron compound in an amount corresponding to from 0.3 to 3.0% by weight as boron, and carbon or a carbon compound in an amount corresponding to from 0.1 to 6.0% by weight as carbon, to a SiC powder having an average particle size of 1.0.mu. or less; blending and molding the mixture; conducting a primary sintering in vacuum or in an inert atmosphere, except nitrogen; and thereafter conducting a secondary sintering at from 1500.degree. to 2300.degree. C. in a pressurized nitrogen atmosphere to produce a silicon carbide heating element having a density of at least 80% based on the theoretical density and an electrical resistivity of 1.0 .OMEGA.-cm or less.

Abstract: A microwave absorber, particularly, a microwave absorber intended for use in an electron beam accelerator, having an increased maximum power characteristic. The microwave absorber is formed of a body of dense silicon carbide having a hollow portion and a closed tip end portion. A pipe of high melting point glass or alumina is inserted into the hollow portion. Cooling water is guided through the pipe and circulated through the hollow portion of the body of the absorber.