Agency of Industrial Science and Technology

Other

Sumitomo Electric Industries, Limited

Hiroshi Yamashita

Makoto Kinoshita

Ichiro Matsubara

Saburo Kose

Naoyuki Kitamura

Kenichi Kinugawa

Kohei Fukumi

Isao Kondoh

Jun Matsuoka

Toru Ogura

Hideo Tanigawa

Tomoji Kawai

Osamu Yamada

Mitsue Koizumi

Yoshinari Miyamoto

Kimiaki Tanihata

Manshi Ooyanagi

A process for producing a glass having a rod refractive index distribution, which includes pressing a glass at a temperature below the glass transition temperature to form a glass having a density increased towards the surface layer thereof, or alternatively includes heating a glass at a temperature around the transition temperature at the lowest to prepare glass having a uniformly enhanced density and heating the treated glass under a pressure lower than the applied pressure at a temperature below the glass transition temperature of the glass to prepare a rod glass having a density increased towards the central portion.

Glass having refractive index distribution

There is disclosed a single crystalline fibrous superconductive composition represented by the atomic compositional formula: Bi.sub.2 Sr.sub.2 CaCu.sub.2 M.sub.X O.sub.Y wherein 0&lt;X&lt;0.5; 7.8&lt;Y&lt;8.5; and M is at least one member selected from the group consisting of Pb, Sn, Sb, In, Cd, Ga, Ge, K, Li, and Na. This composition is prepared by a process comprising the step of mixing source material with one another to prepare a mixture having an atomic compositional ratio: Bi=1.00, Sr=0.5.about.2.0, Ca=0.5.about.5.0, Cu=1.0.about.7.0, and M=0.1.about.1.0, wherein M is at least one member selected from the group consisting of Pb, Sn, Sb, In, Cd, Ga, Ge, K, Li, and Na, the step of melting the mixture to prepare a molten material having an atomic compositional ratio: Bi=1.00, Sr=0.5.about.2.0, Ca=0.5.about.5.0, Cu=1.0.about.7.0, M=0.1.about.1.0, and O=3.5.about.8.8, the step of quenching the molten material to prepare a solid material, and the step of heat-treating the solid material in a stream of a gas containing oxygen.

Single crystalline fibrous superconductive composition and process for

A process for producing a rod glass having a refractive index distribution, which includes pressing a glass at a temperature below the glass transition temperature to form a glass having a density increased towards the surface layer thereof, or alternatively includes heating a glass at a temperature around the transition temperature at the lowest to prepare glass having a uniformly enhanced density and heating the treated glass under a pressure lower than the applied pressure at a temperature below the glass transition temperature of the glass to prepare a glass having a density increased towards the central portion.

Process for producing rod glass having refractive index distribution

A process for producing a fibrous crystal or single crystal of a superconductor comprising bismuth, strontium, calcium, copper, lead and oxygen, having an atomic composition ratio represented by the formula Bi.sub.2-x Pb.sub.x Sr.sub.1.9-2.1 Ca.sub.1.9-2.1 Cu.sub.3 o.sub.y wherein 0&lt;.times.&lt;0.4 and 10.0&lt;y&lt;11.0, and having a Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 structure (2223 structure).

Superconductor crystal and process for preparing the same

Process for preparing NbN superconducting material, characterized in that a bulk Nb is placed in powder including at least one metal which can be nitriding-burned, and then the powder is heated to be nitriding-burned in pressurized N.sub.2 atmosphere so that the bulk Nb is nitrided by the nitriding-burning of the powder.

Process for preparing NbN superconducting material

Growing community of inventors

Kawanishi, Japan

Hiroshi Yamashita