Tosoh Corporation

Toyo Soda Manufacturing Co., Ltd.

Kiyoshi Kasai

Takaaki Tsukidate

Toshihiko Arakawa

Syoichi Yamauchi

Naomichi Sakai

Tomoyuki Oikawa

Hiroya Nagata

Hiroshi Yamamura

Mutsumi Asano

Yoshitaka Kubota

Hidehiko Misaki

Kohji Tsukuma

Shinji Nagata

Hiroshi Asakura

Kenji Uchino

A novel magnetic carrier is provided which comprises particulate silica containing a magnetic material, having polyacrylamide on the surface thereof in an amount ranging from 0.3 to 5 mmol/g in terms of monomeric acrylamide. A process for producing the magnetic carrier is also provided in which the surface of particulate silica containing a magnetic material is treated with a coupling agent, and the treated particulate silica is reacted with acrylamide and/or polyacrylamide. The magnetic carrier is useful for extraction of nucleic acid. The magnetic carrier can be produced readily by controlling the shape, the particle diameter, and the pore diameter, and is excellent in strength and adsorption efficiency. The extraction of a nucleic acid can be automated by use of the magnetic carrier.

Magnetic carrier, preparation thereof, and method of extraction of nucleic acid

A magneto-optical recording medium and process for production of the same are disclosed, the magneto-recording medium comprising a substrate having thereon a magneto-optical recording film and at least one coating film provided on a light incident side and/or an opposite side thereto, of said magneto-optical recording film for protection of said magneto-optical recording film and/or Kerr effect enhancement, wherein said coating film contains silicon, nitrogen, and hydrogen as constituent elements. The magneto-optical recording medium has excellent reliability, excellent read-out performance properties as well as excellent recording sensitivity while exhibiting high magneto-optical effects and freedom from corrosion.

Magneto-optical recording medium and process for production of the same

An actuator of the present invention is composed of a monomorph-type piezoelectric ceramic. The monomorph-type piezoelectric ceramic is a BaTiO.sub.3 -based ceramic, a PZT based ceramic having Nb, Sb, La, Mn, Nd and Bi, BaTiO.sub.3 --SrTiO.sub.3 -based ceramic containing SrTiO.sub.3 by 20 to 35 mole %, K(Nb, Ta)O.sub.3 -based ceramic, or a ceramic represented by a general formula: [Pb, (A.sub.1/2 B.sub.1/2)](Zr.sub.1-n, Cn)O.sub.3 where A is a monovalent element such as Li, Na, K, Rb, Cs or the like, B is a trivalent element such as Bi, La, Y, Sb, Ga or the like, A and B being both replaceable solid-meltable elements for Pb, C is an element such as Ti, Sn or the like that is a replaceable solid-meltable element for Zr, and n is from 0 to 0.8.

Actuator

A high .alpha.-type silicon nitride powder is prepared by thermally decomposing a mixture of a crystalline silicon nitride powder having an oxygen content of at least 1.0% by weight and a nitrogen-containing silane compound.

Process for preparation of high-type silicon nitride powder

A silicon nitride powder having an enhanced sintering activity is prepared by heating a mixture of a nitrogen-containing silane compound and a sintering aid in a non-oxidizing atmosphere.

Process for preparation of silicon nitride powder of good sintering

A method of manufacturing highly purified silicon nitride including the steps of preparing a nitrogen-containing silane selected from the group consisting of tetra-amide-monosilane and silicon imide, and heat-treating the prepared nitrogen-containing silane in the presence of ammonia in an inner atmosphere at a temperature above 400.degree. C. for a period of at least two hours to obtain silicon nitride, and cooling and collecting the silicon nitride thus formed. The step of preparing the nitrogen-containing silane comprises continuously reacting gaseous silicon tetra-chloride with gaseous ammonia in an inner atmosphere at a temperature of from -30.degree. to 70.degree. C. to produce the nitrogen-containing silane as a product and collecting the product. The resultant silicon nitride so produced has a chlorine content of less than 0.05 weight percent and a nitrogen content of over 38 weight percent.

Method of manufacturing high-purity silicon nitride powder

High-purity .alpha.-type silicon nitride comprised of a granular crystal having an .alpha.-phase content of at least 95%, a nitrogen content of at least 38% by weight and an average particle size of not larger than 3 .mu.m is provided. This high-purity .alpha.-type silicon nitride is prepared by heating a nitrogen-containing silane compound at a temperature of at least about 1,300.degree. C. in a heating furnace comprised of a material containing a metal having a melting point exceeding 1,600.degree. C. and capable of being bonded with oxygen at the heating temperature.

Growing community of inventors

Kanagawa, Japan

Kiyoshi Kasai