Abstract: To lighten the weight of an electromagnetic actuator and a valve-open-close mechanism by forming the stems from a lighter material than conventional. A pair of electromagnets formed of stators and coils are opposed to each other with a gap therebetween. An armature is disposed in the gap so as to be reciprocable between one electromagnet and the other electromagnet by the electromagnets. A first stem for transmitting the movement of the armature from one electromagnet toward the other electromagnet to a valve of the internal combustion engine is inserted in a guide hole formed in the stator of one electromagnet. The first stem is formed of a lighter material than the armature to lighten the weight of the electromagnetic actuator and a valve-open-close mechanism of an internal combustion engine.

Abstract: To lighten the weight of an electromagnetic actuator and a valve-open-close mechanism by forming the stems from a lighter material than conventional. A pair of electromagnets formed of stators and coils are opposed to each other with a gap therebetween. An armature is disposed in the gap so as to be reciprocable between one electromagnet and the other electromagnet by the electromagnets. A first stem for transmitting the movement of the armature from one electromagnet toward the other electromagnet to a valve of the internal combustion engine is inserted in a guide hole formed in the stator of one electromagnet. The first stem is formed of a lighter material than the armature to lighten the weight of the electromagnetic actuator and a valve-open-close mechanism of an internal combustion engine.

Abstract: It is proposed to lessen the weight and improve the mechanical strength of a retainer of a valve open-close mechanism driven by an electromagnetic actuator used in an automotive internal combustion engine. The electromagnetic actuator is mounted in a housing mounted on an internal combustion engine body. A first stem has its tip abutting the valve, which is provided with a retainer and carries a first coil spring. A second stem is provided on the other side of an armature. The second stem has a retainer. Between this retainer and the housing, a second coil spring is mounted. At least one of these parts is made of a metal smaller in specific weight than iron or its alloy. Each retainer has a boss and an arcuate corner portion having a radius of curvature R of 1.0 mm or over between a spring abutting surface and the boss to relieve stress concentration.

Abstract: A hydrogen storage laminated material can be obtained which is capable of achieving reduction in weight as well as being mass-produced industrially while assuring excellent hydrogen storage capability. The hydrogen storage laminated material (10) has a laminated structure of a first layer (6a) and a second layer (7a), wherein the first layer is formed from an alloy or compound including an element of a group 2A or 3A or an element of at least one of the groups 2A and 3A, and at least partially includes a bcc structure, and the second layer is formed from an alloy or compound including an element of one of groups 6A, 7A and 8A or an element of at least one of the groups 6A, 7A and 8A.

Abstract: A hydrogen storage material (1) having excellent hydrogen storage capability and having such a low hydrogen desorption temperature as not to significantly hinder the use thereof, and also capable of being mass-produced, and a manufacturing method of the same can be obtained. The hydrogen storage material has a layered deformation structure including plastic deformation, and one layer (2) of the layered deformation structure is formed from an alloy or compound including an element of groups 2A, 3A and 4A or an element of at least one of the groups 2A, 3A and 4A, and another layer (3) being in contact with the one layer is formed from an alloy or compound including an element of groups 6A, 7A and 8A or an element of at least one of the groups 6A, 7A and 8A.

Abstract: It is proposed to lessen the weight and improve the mechanical strength of a retainer of a valve open-close mechanism driven by an electromagnetic actuator used in an automotive internal combustion engine. The electromagnetic actuator is mounted in a housing mounted on an internal combustion engine body. A first stem has its tip abutting the valve, which is provided with a retainer and carries a first coil spring. A second stem is provided on the other side of an armature. The second stem has a retainer. Between this retainer and the housing, a second coil spring is mounted. At least one of these parts is made of a metal smaller in specific weight than iron or its alloy. Each retainer has a boss and an arcuate corner portion having a radius of curvature R of 1.0 mm or over between a spring abutting surface and the boss to relieve stress concentration.

Abstract: A single crystal of a nitride having a length of not less than 10 mm, a width of not less than 10 mm and a thickness of not less than 300 .mu.m, or having a length of not less than 20 mm and a diameter of not less than 10 .mu.m. In the production of the single crystal, either a mixed powder composed of a nitride powder and an oxide powder or an amorphous nitride powder is provided as a source material powder, the source material powder is heated in a nitrogen atmosphere or in a nitrogen atmosphere containing hydrogen and/or carbon at a temperature below the sublimation temperature or melting temperature of the nitride to decompose and vaporize the nitride powder, and the decomposed and vaporized component is subjected to crystal growth from the vapor phase on a substrate. The nitride single crystal is useful as a bulk material for heat sinks, electric and electronic components, such as semiconductors, optical components, and components of electric equipment and office automation equipment.

Abstract: A semiconductor device comprising single crystal films consisting of at least one III-V nitride selected from the group consisting of gallium nitride, aluminum nitride, boron nitride, indium nitride, and single-crystalline alloys of these nitrides, the single crystal films being provided on a single crystal substrate of aluminum nitride either directly or through a low-temperature growth buffer layer of at least one III-V nitride. This semiconductor device is useful as a short-wavelength light emitting device capable of conducting continuous oscillation or a diode which is operated at a high temperature. The AlN single crystal substrate is matched in lattice constant and coefficient of thermal expansion with the single crystal film of a III-V nitride and the single crystal films is grown with good crystallinity on the substrate.

Abstract: An aluminum nitride sintered body comprising aluminum nitride crystals belonging to a Wurtzite hexagonal crystal system wherein the 3 axes a, b and c of the unit lattice of the crystal are defined such that the ratio b/a of the lengths of the axes b and a is 1,000 near the center of the crystal grain and lies within the range 0.997-1.003 in the vicinity of the grain boundary phase. Aluminum nitride sintered body is produced by sintering a molded body of a raw material powder having aluminum and nitrogen as its principal components at a temperature of 1700.degree.-1900.degree. C. in a non-oxidizing atmosphere having a partial pressure of carbon monoxide or carbon of not more than 200 ppm and then cooling the sintered body to 1500.degree. C. or a lower temperature at a rate of 5.degree. C./min or less. The aluminum nitride sintered body has a greatly improved thermal conductivity and, therefore, is suitable for heat slingers, substrates or the like for semiconductor devices.

Abstract: An aluminum nitride sintered body comprising aluminum nitride crystals belonging to a Wurtzite hexagonal crystal system wherein the 3 axes a, b and c of the unit lattice of the crystal are defined such that the ratio b/a of the lengths of the axes b and a is 1.000 near the center of the crystal grain and lies within the range 0.997-1.003 in the vicinity of the grain boundary phase. Aluminum nitride sintered body is produced by sintering a molded body of a raw material powder having aluminum and nitrogen as its principal components at a temperature of 1700.degree.-1900.degree. C. in a non-oxidizing atmosphere having a partial pressure of carbon monoxide or carbon of not more than 200 ppm and then cooling the sintered body to 1500.degree. C. or a lower temperature at a rate of 5.degree. C./min or less. The aluminum nitride sintered body has a greatly improved thermal conductivity and, therefore, is suitable for heat slingers, substrates or the like for semiconductor devices.

Abstract: An aluminum nitride sintered body has a high breakdown voltage for serving as a substrate material particularly suited to highly integrated circuits. The aluminum nitride sintered body contains titanium, which is included as a solid solute in the aluminum nitride crystal lattice in a weight ratio of at least 50 ppm and not more than 1000 ppm. The unpaired electron concentration in the sintered body as determined from an absorption spectrum of electron spin resonance is at least 1.times.10.sup.13 /g. At least 0.1 percent by weight and not more than 5.0 percent by weight, in terms of TiO.sub.2, of an oxy-nitride of titanium and aluminum exists in the aluminum nitride sintered body. The aluminum nitride sintered body has a breakdown voltage of 20 kV/mm. The sintered body is obtained by nitriding aluminum nitride raw material powder in a nitrogen atmosphere at a temperature of 800 to 1400.degree. C., adding an oxy-nitride of titanium thereto with a sintering assistant, and sintering the mixture.

Abstract: An aluminum nitride powder having a surface layer containing an oxynitride characterized in that the surface layer of the aluminum nitride particle contains an aluminum oxynitride which has an oxygen content of 5 to 75 mol % in terms of Al.sub.2 O.sub.3 /(Al.sub.2 O.sub.3 +AlN). The surface layer of the aluminum nitride powder may contain, besides the aluminum oxynitride, at least one other oxynitride selected from among oxynitrides of Mg, Ca, Ba, Ti, V, Cr, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ru, Hf, Ta, W, Li, B, Si, Y, Sc and rare metal elements and the aluminum oxynitride and at least one other oxynitride have a total oxygen content in the range of 10 to 75 mol % in terms of (3.times.oxygen amount)/(3.times.oxygen amount+nitrogen amount).

Abstract: An aluminum nitride sintered body has a high breakdown voltage for serving as a substrate material particularly suited to highly integrated circuits. The aluminum nitride sintered body contains titanium, which is included as a solid solute in the aluminum nitride crystal lattice in a weight ratio of at least 50 ppm and not more than 1000 ppm. The unpaired electron concentration in the sintered body as determined from an absorption spectrum of electron spin resonance is at least 1.times.10.sup.13 /g. At least 0.1 percent by weight and not more than 5.0 percent by weight, in terms of TiO.sub.2, of an oxy-nitride of titanium and aluminum exists in the aluminum nitride sintered body. The aluminum nitride sintered body has a breakdown voltage of 20 kV/mm. The sintered body is obtained by nitriding aluminum nitride raw material powder in a nitrogen atmosphere at a temperature of 800.degree. to 1400.degree. C., adding an oxy-nitride of titanium thereto with a sintering assistant, and sintering the mixture.

Abstract: Disclosed herein is a measuring apparatus and a measuring method which can measure a physical property value such as an oxygen content or thermal conductivity of a sample material such as an aluminum nitride sintered body with high accuracy, over the entire material in a short time. A microwave oscillation source generates microwaves. A sample material to be evaluated, such as an aluminum nitride sintered body, is placed in a cavity resonator, irradiated with microwaves (M), and subjected to a magnetic field (H) applied by electromagnets. An amount of microwaves absorbed by the object is measured by a microwave absorption measuring unit. This amount of microwave absorption is obtained from an electron spin resonance spectrum. The concentration of unpaired electrons in the object is obtained from the measured amount of microwave absorption on the basis of a known relation between an amount of microwave absorption and concentration of unpaired electrons.

Abstract: A heat conductive aluminum nitride sintered body contains 100 parts by weight of aluminum nitride, at least 0.005 parts by weight and not more than 0.5 parts by weight of carbon, at least 0.01 parts by weight and not more than 15 parts by weight of a rare earth aluminum oxide in terms of the simple substance of a rare earth element, and at least 0.01 parts by weight and not more than 15 parts by weight of at least one element selected from a group of compounds containing elements belonging to the groups IVB, VB and VIB of the periodic table in terms of the simple substance of the element. Such a sintered body has a heat conductivity of at least 100 W/m.multidot.K. and not more than 270 W/m.multidot.K. at room temperature.

Abstract: An AlN sintered body which has a color within the range of gray to black and a thermal conductivity within the range of 100 to 270 W/m.multidot.K at room temperature. Such a body is useful as an electronic material and a method of preparing the same. The AlN sintered body contains 100 parts by weight of AlN, 0.005 to 0.5 parts by weight of carbon, not more than 1 part by weight of a boron compound in terms of the simple substance of boron, 0.01 to 15 parts by weight of a rare earth aluminum oxide in terms of the simple substance of the rare earth element, and 0.01 to 15 parts by weight of a compound containing an element belonging to the group IVB of the periodic table in terms of the simple substance of the element. This AlN sintered body is obtained by shaping a mixture of the above components into a prescribed configuration and thereafter firing the as-formed compact in a non-oxidizing atmosphere containing at least 10 percent by volume of nitrogen, at a temperature of 1500.degree. to 2100.degree. C.