Sumitomo Electric Industries, Limited

The Tokyo Electric Power Company, Incorporated

Kabushiki Kaisha Toshiba

The Toyko Electric Power Company, Incorporated

Takahiko Yamamoto

Tsukushi Hara

Noriyuki Yoshida

Satoshi Takano

Kiyoshi Okaniwa

Shigeru Okuda

Noriki Hayashi

Daisuke Ito

Kazuyuki Tsurunaga

Takeshi Ohkuma

Takamitsu Tada

A current limiter having a plurality of current limiting units provided for electric paths constituting a plurality of phases. Each current limiting unit is constituted by a superconducting coil functioning as a first current limiting element formed in a non-inductive winding manner by connecting two superconducting coils in series, which superconducting coils are wound in opposite directions and equal in size and number of turns, and a superconducting coil functioning as a second current limiting element connected in parallel to the first current limiting element and having a predetermined impedance value. These current limiting units are contained within a cryostat and separated by a magnetic shield member for electromagnetically isolating the respective phases.

Superconducting fault current limiter

In a method of preparing an oxide superconducting thin film having a composition of Y-Ba-Cu-O, for example, using laser ablation, which comprises the steps of applying a laser beam to a target containing components of an oxide superconductive material and depositing particles, being thereby scattered from the target, on a substrate, the oxygen gas flow rate during film deposition is set to be at least 50 SCCM, the oxygen gas pressure during film deposition is set to be 10 to 1000 mTorr, the distance between a target 9 and a substrate 10 is set to be 40 to 100 mm, the temperature of the substrate 10 is set to be 600.degree. to 800.degree. C., the energy density of a laser beam 7 on the surface of the target 9 is set to be at least 1 J/cm.sup.2, and the laser pulse energy is set to be at least 10 mJ.

In-situ laser ablation method for forming oxide superconducting films

In order to enable formation of a smooth and dense oxide superconducting film with no clear appearance of grain boundaries in a fine structure even at a high film forming rate, a laser ablation method is employed to apply a laser beam 2 to a target 1 containing components of an oxide superconductive material and deposit particles, which are thus scattered from the target 1, on a substrate 3, while gaseous oxygen is supplied from a gaseous oxygen inlet 7 toward laser plasma 6, which is generated by the application of the laser beam 2.

Method of and apparatus for preparing oxide superconducting film

In order to enable formation of a smooth and dense oxide superconducting film with no clear appearance of grain boundaries in a fine structure even at a high film forming rate, a laser ablation method is employed to apply a laser beam 2 to a target 1 containing components of an oxide superconductive material and deposit particles, which are thus scattered from the target 1, on a substrate 3, while gaseous oxygen is supplied from a gaseous oxygen inlet 7 toward laser plume 6, which is generated by the application of the laser beam 2, and to a portion of the target irradiated with said laser.

Method of preparing oxide superconducting films by laser ablation

In order to prepare an elongated oxide superconducting material which exhibits a high critical current density, a tape-type substrate (7) of silver, for example, formed by unidirectional solidification is prepared and an excimer laser beam (9) is applied to target (8) of an oxide superconductor to deposit atoms and/or molecules being scattered from the target (8) on the substrate (7), thereby forming an oxide superconducting film on the substrate (7).

Laser ablation method of preparing oxide superconducting films on

An oxide superconducting thin film formed by laser ablation comprises a matrix formed of c-axis oriented superconducting phases and foreign phases which are different in crystal orientation from the matrix. In order to improve critical current density of the oxide superconducting thin film, preferably selected are such conditions that the size of each superconducting phase in its a-b plane is not more than 0.1 .mu.m in diameter, the size of each superconducting phase along its c-axis direction is equal to the thickness of the oxide superconducting thin film, the foreign phases at least partially pass through the oxide superconducting thin film along the direction of thickness, the size of each foreign phase is at least 0.01 .mu.m and not more than 5 .mu.m in diameter, each foreign phase has an a-axis or a c-axis perpendicularly oriented with respect to the major surface of the oxide superconducting thin film, and the like.

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Chofu, Japan

Takahiko Yamamoto