The Foundation: the Research Institute for Special Inorganic Materials

Ube Industries, Inc.

Japan Atomic Energy Research Institute

Sony Corporation

Ngk Insulators, Inc.

Nippon Carbon Co., Ltd.

Shin-etsu Chemical Co., Ltd.

Mitsubishi Seiko Kabushiki Kaisha

Kaken Co., Ltd.

Ube Industires, Ltd.

Kurosaki Refractoris Co., Ltd.

The Research Institute for the Foundation: Special Inorganic Materials

Yoshio Hasegawa

Kiyohito Okamura

Seishi Yajima

Takemi Yamamura

Mitsuhiko Sato

Toetsu Shishido

Tadao Seguchi

Shunichi Kawanishi

Masana Ugaji

Katsuyoshi Tatenuma

Yoshiyasu Kuroo

Taketoshi Takeuchi

Minoru Takamizawa

Akira Hayashida

Yoshihumi Takeda

Kazushige Fukuda

Masaaki Hamano

Hiroshi Kawamura

Naoki Sakamoto

Takashi Irie

Kimiyuki Kamino

Kiyoyuki Kurosawa

Takehiro Yamane

Seishi Yajima, Deceased

Takemi Yamaura

Mizuka Nishino

Akiko Noda, Heir

Takeo Kobori

Akiko Noda

Mantaro Yajima

Masakazu Tanase

Sadao Mori

The invention provides a method for recovering metal beryllium from waste beryllium that has become radioactive in the reaction with neutrons, by converting the radioactive beryllium to halogenated beryllium with a halogen gas such as chlorine, bromine or iodine, and subsequently submitting the halogenated beryllium to thermal decomposition. In this way, the invention allows effective recovery of metal beryllium from waste, radioactive beryllium, thereby reducing production of radioactive wastes and ensuring an economical use of natural resources.

Method of recovering radioactive beryllium

Mo adsorbent for .sup.99 Mo-.sup.99m Tc generators has a skeleton structure having mainly repeating units represented by the general formula; ##STR1## wherein X is a halogen atom or alkoxide group having one to six carbon atoms, 10% or more of X is halogen, R is an alkylene, polymethylene, or carbon chain having unsaturated bond, repeating unit (D) is bonded to any one of repeating units (A), (B), and (C), the branch structure is controlled by the content of repeating units (A), (B), and (C), the adsorbent is insoluble in water and adsorbs selectively only Mo from an aqueous solution containing Mo, and elutes .sup.99m Tc generated from a radioactive isotope .sup.99 Mo. This Mo adsorbent uses .sup.99 Mo obtained from natural Mo by (n, .gamma.) method, therefore, a generator having the same size as conventional .sup.99m Tc generators is realized.

Mo adsorbent for .sup.99 Mo-.sup.99m Tc generators and manufacturing

A process for manufacturing SiC-based ceramic precursors by curing a polycarbosilane shaped body while it is in contact with vapor of at least one hydrocarbon selected from the group consisting of halogenated hydrocarbons and unsaturated hydrocarbons of ethylene series and acetylene series. This process can cure polycarbosilane shaped bodies without introducing oxygen thereinto and requires no special apparatuses. The obtained precursor is suited for synthesizing SiC-based ceramics efficiently without deteriorating characteristics thereof, particularly excellent in high-temperature strength.

Process for manufacturing SiC-based ceramic precursors

An organic silazane polymer is prepared by passing a silazane compound in por form through a hollow tube heated at 400.degree. to 700.degree. C. for activation and thermally polymerizing the silazane compound in a liquid phase. Inorganic fibers can be prepared from the organic silazane polymer by melt spinning, infusibilizing, and sintering. An apparatus for preparing an organic silazane polymer is also provided, comprising a heated reactor vessel for evaporating and thermally polymerizing a silazane compound, a heated hollow tube in flow communication with said reactor vessel for receiving the silazane compound vapor and heating it at 400.degree. to 700.degree. C. for activation, and a conduit, with a condenser for condensing the vapor, for feeding the condensed silazane compound back to the reactor.

Method and apparatus for preparing organic silazane polymer and method

A high purity and high strength inorganic silicon nitride continuous fiber substantially composed of Si and N with excellent properties can be provided. A method of producing the fiber is also disclosed.

High purity and high strength inorganic silicon nitride continuous fiber

A continuous inorganic fiber consisting of Si, N and O has excellent physical, chemical and electrically insulating properties, is superior to carbon fiber in wettability with metal, is low in reactivity with metal, and can be used not only as a reinforcing fiber for fiber-reinforcing type metals and fiber-reinforcing type ceramics, but also in electrical insulating materials and in heat-resistant materials.

Method of producing continuous inorganic fiber consisting of Si, N and O

Organopolyarylsilanes, process for manufacturing the same and fibers

A current limiting horn device for a transmission line supported by sets of insulators suspended from arms of steel towers. The device includes horns located respectively at charging and earthing portions of each set of the insulators and spaced horizontally apart a predetermined distance from a vertical axis of the set of the insulators. At least one of the horns is provided with an arrester element of a resistance having a non-linearity. According to the invention, a ratio Z/Zo of a distance Z between the horns to a total length Zo of the one set of insulators is not more than 0.5, thereby when extraordinary voltage caused by lightening surge is applied to the transmission line, securely causing flash-over between horns to prevent any earthing accident which would otherwise occur in the transmission line.

Current limiting horn device for transmission line

Silicon carbide-carbon composite molded product and process for

Continuous inorganic fibers consisting substantially of Si, Zr and C and optionally of O, said fibers being composed of (1) an amorphous material consisting substantially of Si, Zr and C and optionally of O, or (2) an aggregate consisting substantially of ultrafine crystalline particles of .beta.-SiC, ZrC, a solid solution of .beta.-SiC and ZrC and ZrC.sub.1-x wherein O&lt;x&lt;1 and having a particle diameter of not more than 500 .ANG., in which amorphous SiO.sub.2 and ZrO.sub.2 sometimes exist in the neighborhood of these ultrafine crystalline particles, or (3) a mixture of said amorphous material (1) and said aggregate (2) of ultrafine crystalline particles. The aforesaid continuous inorganic fibers can be produced by the following steps: a first step of preparing a semi-inorganic block copolymer comprising polycarbosilane blocks having a main chain skeleton composed mainly of carbosilane units of the formula --Si--CH.sub.2 --, each silicon atom of said carbosilane units having bonded thereto a side-chain group selected from the class consisting of hydrogen, lower alkyl and phenyl, and zirconoxane units of the formula --Sr-O--; a second step of preparing a spinning dope of said semi-inorganic block copolymer and spinning the dope; a third step of subjecting the resulting fibers to a treatment of rendering them infusible under tension or under no tension; and a fourth step of firing the infusible fibers at a temperature of 800.degree. to 1800.degree. C. in a vacuum or in an atmosphere of an inert gas or a reducing gas.

Continuous inorganic fibers and process for production thereof

Continuous inorganic fiber consisting of Si, N and O and a method of

A molded product consisting mainly of silicon carbide and a process for mfacturing the same. This invention is to provide a product having a desired or complicated shape and a process which enables the manufacture of any such product at a drastically lower temperature than any conventional process. This object is attained by applying an organic silicon polymer having a skeleton composed mainly of carbon-silicon bonds by impregnation or adherence to a base material having a desired shape, and by burning the base material at a temperature of 700.degree. C. to 2,000.degree. C. in a vacuum or in a nonoxidizing gas atmosphere. The product of this invention has a fibrous, granular and/or filmy carbon structure in the matrix consisting mainly of SiC. The product of this invention is useful for a wide variety of applications, for example, for making heat-resistant structural members of electronic devices.

An organosilicon polymer whose main-chain skeleton is composed mainly of following structural units (A), (B), (C), (D), (E) and (F) ##STR1## wherein R represents CH.sub.3 or H, said structural units forming linear, branched and cyclic structures, and said main-chain skeleton further having a polysilane skeleton ##STR2## (2.ltoreq.n.ltoreq.10). The said organosilicon polymer can be produced by adding at least one anhydrous metal halide to a polysilane having the structure ##STR3## the amount of the metal halide being 0.5 to 10% by weight based on the weight of the polysilane; and heating the mixture in an atmosphere inert to the reaction.

Organosilicon polymer and process for production thereof

A process for producing a sintered ceramic body, which comprises heating a semi-inorganic block copolymer at a temperature of from 500.degree. to 2300.degree. C. in an environment of vacuum or inert gases, reducing gases or hydrocarbon gases, said copolymer comprising polycarbosilane blocks having a main-chain skeleton composed mainly of carbosilane units of the formula (Si--CH.sub.2) and zirconoxane units of the formula (Zr--O); and shaping the heated product, and simultaneously with, or after, the shaping of the heated product, sintering the shaped product at a temperature of from 800.degree. C. to 2300.degree. C. in an environment of vacuum or inert gases, reducing gases or hydrocarbon gases; and a sintered ceramic body consisting substantially of Si, Zr and C and optionally of O, said sintered body being composed substantially of

Process for production of sintered ceramic body

Growing community of inventors

Oharai, Japan

Yoshio Hasegawa