Abstract: This magnesium oxide powder contains secondary particles in which a plurality of primary particles of magnesium oxide having a crystal phase and a grain boundary phase are at least partially fused together by the grain boundary phase, and a median diameter obtained by a laser diffraction scattering method is 300 ?m or less.

Abstract: This magnesium oxide powder contains secondary particles in which a plurality of primary particles of magnesium oxide having a crystal phase and a grain boundary phase are at least partially fused together by the grain boundary phase, and a median diameter obtained by a laser diffraction scattering method is 300 µm or less.

Abstract: Acicular strontium carbonate particles are manufactured by introducing gaseous carbon dioxide into an aqueous solution or suspension of strontium hydroxide having a concentration of 1 to 20 wt. %, at a flow rate of 0.5 to 200 mL/min., relative to one gram of the strontium hydroxide, while stirring the solution or suspension in the presence of a dicarboxylic acid, in which the dicarboxylic acid comprises a divalent linear hydrocarbon group having one to four carbon atoms and carboxyl group bonded to each terminals, with the proviso that the linear hydrocarbon group may be substituted with one or more C1-6 alkyl groups, and thus carbonating the strontium hydroxide.

Abstract: Dispersibility of an alkaline earth metal carbonate micropowder in a polymer resin or in an organic solvent is improved by treating the surface of the alkaline earth metal micropowder with a surfactant having hydrophilic groups and hydrophobic groups and groups that form anions in water.

Abstract: An acicular strontium carbonate fine powder having a mean length of 150 nm or less and a mean aspect ratio of 1.5 or more and containing acicular strontium carbonate particles having a length of 200 nm or more in an amount of 5% or less in terms of number of acicular particles is improved in its dispersibility in hydrophobic organic solvent by treating the acicular strontium carbonate fine powder with a combination of polycarboxylic acid having a side chain of a polyoxyalkylene group or its anhydride and amine having a polyoxyalkylene group and a hydrocarbyl group.

Abstract: An acicular strontium carbonate fine powder having a mean length of 150 nm or less and a mean aspect ratio of 1.5 or more and containing acicular strontium carbonate particles having a length of 200 nm or more in an amount of 5% or less in terms of number of acicular particles is improved in its dispersibility in hydrophobic organic solvent by treating the acicular strontium carbonate fine powder with a combination of polycarboxylic acid having a side chain of a polyoxyalkylene group or its anhydride and amine having a polyoxyalkylene group and a hydrocarbyl group.

Abstract: Acicular strontium carbonate particles are manufactured by introducing gaseous carbon dioxide into an aqueous solution or suspension of strontium hydroxide having a concentration of 1 to 20 wt. %, at a flow rate of 0.5 to 200 mL/min., relative to one gram of the strontium hydroxide, while stirring the solution or suspension in the presence of a dicarboxylic acid, in which the dicarboxylic acid comprises a divalent linear hydrocarbon group having one to four carbon atoms and carboxyl group bonded to each terminals, with the proviso that the linear hydrocarbon group may be substituted with one or more C1-6 alkyl groups, and thus carbonating the strontium hydroxide.

Abstract: Dispersibility of an alkaline earth metal carbonate micropowder in a polymer resin or in an organic solvent is improved by treating the surface of the alkaline earth metal micropowder with a surfactant having hydrophilic groups and hydrophobic groups and groups that form anions in water.

Abstract: A fine strontium carbonate powder having a BET specific surface area of 20 to 150 m2/g, which comprises spherical particles having a mean aspect ratio of 2.0 or less shows high dispersibility in liquid media and is of value for producing dielectric ceramic materials such as strontium titanate.

Abstract: A fine strontium carbonate powder having a BET specific surface area of 20 to 150 m2/g, which comprises spherical particles having a mean aspect ratio of 2.0 or less shows high dispersibility in liquid media and is of value for producing dielectric ceramic materials such as strontium titanate.

Abstract: A photodiode comprises e.g. an n-type semiconductor layer, a p-type semiconductor region selectively formed in a central part from a surface of the n-type semiconductor layer, a dish-like shaped pn-junction therebetween, an annular electrode formed on the p-type region, an electrode formed on the other side of the n-type semiconductor layer, and a dielectric layer deposited on the n-type semiconductor layer for preventing light from attaining to the semiconductor layer by reflecting a dielectric multilayer consisting of two different media having effective thicknesses equal to one fourth of the wavelength of the light.

Abstract: A semiconductor device having an ohmic electrode which has formed on the surface of a p-type III-V compound semiconductor an assembly of a first Ti layer, a second Zn layer, a third metal layer made of one element selected from among Pt, Mo, W and Cr, and a fourth Au layer is disclosed. A process for producing such semiconductor device is also disclosed.The present invention provides a novel ohmic electrode having a low contact resistance comparable to that of a conventional electrode formed by deposition of successive Au, An and Au layers. The novel electrode also has the advantage of another conventional electrode wherein the Au electromigration is held to a minimum by forming an assembly of a Ti layer, a metal layer made of an element selected from among Pt, Mo, W and Cr, and an Au layer.

Abstract: A semiconductor device having an ohmic electrode which has formed on the surface of a p-type III-V compound semiconductor an assembly of a first Ti layer, a second Zn layer, a third metal layer made of one element selected from among Pt, Mo, W and Cr, and a fourth Au layer is disclosed. A process for producing such semiconductor device is also disclosed.The present invention provides a novel ohmic electrode having a low contact resistance comparable to that of a conventional electrode formed by deposition of successive Au, Zn and Au layers. The novel electrode also has the advantage of another conventional electrode wherein the Au electromigration is held to a minimum by forming an assembly of a Ti layer, a metal layer made of an element selected from among Pt, Mo, W and Cr, and an Au layer.