Sumitomo Electric Industries, Limited

Other

Japan Atomic Energy Research Institute

Yuichi Yamada

Naoki Ayai

Minoru Yokota

Shigeo Saito

Hiroshi Tsuji

Masayuki Hirose

Toshinari Ando

Masayuki Nagata

Masatoshi Suzuki

Kenichi Takahashi

Noboru Edagawa

Yoshikazu Takahashi

Masataka Nishi

Akira Mikumo

Takehiro Tsuritani

Hideo Nakajima

Makoto Sugimoto

Norikiyo Koizumi

Masasyuki Nagata

A superconducting cable line includes a heat insulation pipe for a fluid for transporting liquid hydrogen, a superconducting cable housed in the heat insulation pipe for a fluid, and heat exchange means for performing a heat exchange between liquid hydrogen and a refrigerant of the cable. The superconducting cable includes a cable core inside a heat insulation pipe for a cable and is housed in the heat insulation pipe for a fluid to form a low temperature environment around the cable and a double heat insulation structure including the heat insulation pipe. Therefore, since heat intrusion into the superconducting cable is reduced and the refrigerant is cooled with liquid hydrogen, the line can reduce energy for cooling the refrigerant.

Superconducting cable line

A superconducting cable line includes a heat insulation pipe for a fluid for transporting a fluid having a temperature lower than an ordinary temperature and a superconducting cable housed in the heat insulation pipe for a fluid. The superconducting cable including a cable core in a heat insulation pipe for a cable is housed in the heat insulation pipe for a fluid to make a temperature difference between the inside and outside of the heat insulation pipe smaller than that in a situation of laying in an atmosphere. In addition, the superconducting cable has a double heat insulation structure formed with the heat insulation pipe for a cable and the heat insulation pipe for a fluid. Therefore, the superconducting cable line can effectively reduce heat intrusion from the outside into the cable.

An object of this invention is to improve transmission characteristics in WDM transmission. An optical transmitter ( ) wavelength-multiplexes signal lights of wavelengths &lgr; through &lgr;n and outputs them onto an optical transmission line ( ). Optical powers of the signal lights of the respective wavelength through &lgr;n are identical or become smaller proportional to the wavelength. One repeater span of the optical transmission line ( ) is composed of an optical fibers ( ) and an optical amplifier ( ), and a gain equalizer ( ) is dispersed every several repeater spans. The optical amplifier ( ) in the repeater span amplifies each signal light so that optical power of a signal on the shorter wavelength side becomes smaller than that of a signal on the longer wavelength side. The gain equalizer ( ) equalizes optical powers of the respective signal lights.

Optical transmission system, its method, and optical amplification transmission line

An Nb.sub.3 Al multi-filamentary superconducting wire capable of realizing both stabilization of a superconducting state and increase in capacity is provided. The Nb.sub.3 Al multi-filamentary superconducting wire includes a core formed of copper or copper alloy and located at the center of the wire; a multi-filamentary superconductor layer located around the core and having filaments containing Nb and Al as constituent elements embedded in a matrix formed of copper or copper alloy; and a high resistance layer located around the multi-filamentary superconductor layer, and is characterized in that a sectional area of the core is at least 15% of the total sectional area of the core and the matrix and that the core and the matrix are formed of copper or copper alloy of at least 99.9% purity.

Nb.sub.3 Al multi-filamentary superconducting wire

The method of preparing an NB.sub.3 Al superconducting wire comprises the steps of passing an Nb/Al composite wire consisting of an Nb metal or an Nb alloy and an Al metal or an Al alloy through a furnace for heating the same from the room temperature to a prescribed temperature, subsequently passing the same through the furnace for holding the same at the prescribed temperature, and subsequently passing the same through a cooling part for cooling the same from the prescribed temperature to the room temperature, and these steps are continuously carried out by continuously moving the wire. According to the present invention, it is possible to obtain an Nb.sub.3 Al superconducting wire having homogeneous characteristics along its overall width with a high critical current density.

Method of preparing Nb.sub.3 Al superconducting wire

Disclosed herein is a wire for an Nb.sub.3 X superconducting wire, which is improved in workability and soundness of a diffusion barrier layer without increasing the diffusion barrier layer in thickness. This wire for an Nb.sub.3 X superconducting wire comprises a wire which is prepared by superposing and winding up a first sheet consisting of pure Nb or an Nb alloy and a second sheet consisting of metal atoms X, reacting with Nb for forming a compound exhibiting superconductivity, or an X alloy, a stabilizing material layer which is provided to enclose the wire, and a diffusion barrier layer which is provided between an outer surface of the wire and an inner surface of the stabilizing material layer for preventing the metal atoms X from being diffused in the stabilizing material layer, and the diffusion barrier layer is made of a metal material having larger tensile strength than that of the first sheet. It is possible to obtain a high-performance Nb.sub.3 X superconducting wire having a high critical current density and a large residual resistance ratio of the stabilizing material, by heat treating this wire.

Wire for Nb.sub.3 X superconducting wire

A method of manufacturing an Nb.sub.3 Al superconducting wire includes a step of forming a wire by a jelly-roll process, a first thermal step of heating the obtained wire at a temperature of 500.degree. to 700.degree. C. for at least 10 hours for diffusing Al in Nb while suppressing formation of Nb.sub.3 Al, and a second thermal step of heating the wire, after the first thermal step, at a temperature of 800.degree. to 1050.degree. C. for about 0.01 to 10 hours, thereby forming Nb.sub.3 Al. In the jelly-roll process, a sheet of Nb and a sheet of Al are lap-wound on a copper core. The material obtained by such lap winding is inserted in a copper pipe, and then subjected to drawing. The drawn wire is cut to obtain a plurality of segments. The plurality of segments are bundled and charged in a copper pipe, and then subjected to drawing. The resulting drawn wire is subjected to the first and second thermal steps. In this manner a superconducting material having a high critical current density under a high magnetic field is obtained.

Methods of manufacturing Nb.sub.3 Al superconducting wire and coil

A composite superconducting wire using ceramic superconductor material in which one or more elongated superconductor material are accommodated in one or more grooves formed on an elongated reinforcing member so that a long size superconductor wire can be provided. Various methods of producing such composite superconductor wire are also disclosed.

Composite superconductor and method of the production thereof

A composite superconducting wire using ceramic superconductor material in which one or more elongated superconductor material are accomodated in one or more grooves formed on an elongated reinforcing member so that a long size superconductor wire can be provided. Various methods of producing such composite superconductor wire are also disclosed.

Growing community of inventors

Osaka, Japan

Yuichi Yamada