Abstract: A vacuum vessel has a member to be cooled to a low operating temperature inside the vacuum vessel and a main cooling circuit having fluid for cooling the member to operating temperature. The main cooling circuit has first fluid refrigerating means located at the vacuum vessel. To achieve rapid cooling, there is a pre-cooling circuit having the fluid for pre-cooling the member towards the operating temperature. The pre-cooling circuit has second fluid refrigerating means operating independently of the first fluid refrigerating means. The pre-cooling circuit cools the main cooling circuit, prior to operation of the main cooling circuit, by passage of the fluid from the pre-cooling circuit into the main cooling circuit. A heat shield cooling circuit for cooling a heat shield cools the second fluid refrigerating means of the pre-cooling circuit.

Abstract: Oxide materials of (L.sub.x A.sub.1-x).sub.i MO.sub.y, (L.sub.x A.sub.1-x).sub.i M.sub.1-z Cu.sub.z O.sub.y and (L.sub.x A.sub.1-x).sub.i MO.sub.j-.delta. G.sub.k, wherein L is Sc, Y, lanthanides, etc.; A is Ba, Sr. Ca, etc.; M is V, Nb, Ta, T, Zr or Hf; 0<x<1; 0<z<1; i=1, 3/2 or 2; 0<y.ltoreq.4; Gis F, Cl or N; .delta. is oxygen defect, and having a perovskite-like crystal structure, show superconductivity at a temperature higher than the liquid nitrogen temperature.

Abstract: A refrigerator having a pressurizing device, a coldness generating device for generating coldness by expanding a portion of operating fluid which has been pressurized by the pressurizing device and a fluid passage through which the operating fluid is, via a device to be cooled, again circulated to the pressurizing device after the residual portion of the operating fluid has been cooled by the coldness generating device. A regenerator type heat exchanger is disposed in the fluid passage through which the operating fluid passes, and a switch device switches the flow of the operating fluid in the fluid passage to the reverse direction at a predetermined time period.

Abstract: A cryopump for effecting a cooling operation by a freezing medium such as liquid helium. A plurality of radiation-heat shield plates for protecting cryopanels against an external heat radiation are provided in opposed relation to a gas inlet of the cryopump. Particularly, a plurality of groups of such radiation-heat shield plates are provided in such a manner that the radiation-heat shield plates of each group are arranged in a multi-stage manner in registry with one another in the direction of the depth of the cryopump and are disposed in parallel relation to one another. Each of the cryopanels is disposed adjacent to a rear surface of respective radiation-heat shield plates facing away from the gas inlet. With this construction, the gas molecules reflected by those radiation-heat shield plates and by a rear wall of the cryopump, are less liable to reach the gas inlet, and tend to be condensed at an increased rate on those cryopanels.

Abstract: In a cryostat with a refrigerator containing a superconductive magnet, in which a material to be cooled and a low temperature end of the refrigerator for cooling the to-be-cooled material are disposed within a heat-insulating tank, the refrigerator is connected in unison with a part of a structural member other than the heat-insulating tank by a rigid coupling member. Accordingly, a heat portion of the refrigerator is tightly coupled to a magnetic shield member having a large mass and is connected to a vacuum container through bellows. The end portion of the refrigerator is formed in unison with heat shield sleeves and/or the heat shield tank through heat-conductive material having elasticity. Also, in order to prevent the leakage of the sound or noise from the heat portion, a sound-insulating cover is provided also for passages connecting to the head portion and is fixed to the magnetic shield member.

Abstract: Oxide materials having the formulae (L.sub.x A.sub.1-x).sub.i MO.sub.y, (L.sub.x A.sub.1-x).sub.i -M.sub.1-z Cu.sub.z O.sub.y and (L.sub.x A.sub.1-x).sub.i MO.sub.j-.delta. G.sub.k, wherein L is Sc, Y, lanthanides, etc.; A is Ba, Sr, Ca, etc.; M is V, Nb, Ta, Ti, Zr or Hf; 0<x<1; 0<z<1; i=1, 3/2 or 2; 0<y.ltoreq.4; G is F, Cl or N; .delta. is oxygen defect, and having a perovskite-like crystal structure, show superconductivity at a temperature higher than the liquid nitrogen temperature these oxide materials can be produced by a substitution diffusion reaction between a substrate and a film or layer deposited on the substrate.

Abstract: A rotary magnetic refrigerator comprising two rotors which are packed with portions of a working substance at equal spacing along the outer circumference thereof, and which are made of a material having a low thermal conductivity, openings that are formed in the outer surfaces of said rotors so as to communicate with a high-temperature cooling medium, housings having cooling portions provided on sides thereof opposite to said openings, means which establishes an intense magnetic field near said openings and which establishes a weak magnetic field near said cooling portions, and means for driving said rotors.

Abstract: A cryogenic liquefied pump system which includes a pump having a drive motor, bearings, a drive shaft, and an impeller adapted to be disposed in a vessel storing a cryogenic liquid. An outer insulating tank is mounted in the vessel and an inner insulating tank is mounted inside the outer insulating tank, with a vacuum layer being interposed between the inner and outer insulating tanks. An inner side of the inner insulated tank, in which the motor and bearings are arranged, is maintained at a room temperature, with a tip portion of the inner insulating tank being formed into an outer case extending into a cryogenic region outside of the outer insulated tank.

Abstract: In a magnetic refrigerator comprising working substances for the magnetic refrigeration and a magnetic field generating device which magnetizes and demagnetizes these working substances, this magnetic refrigerator is provided with a plurality of superconducting coils arranged around the outer periphery of a rotor, a plurality of working substances are arranged around the periphery of said rotor, and the rotor is rotated so that the strength of magnetic fields impressed on the working substances is varied.

Abstract: A cryostat including a horizontal hollow space section of room temperature in which a liquid helium vessel is supported by a plurality of support structures each having a multiple cylinder of small thickness and a liquid nitrogen vessel is supported by a plurality of tension rods.

Abstract: A magnetic refrigerating apparatus including a working material for performing magnetic refrigeration, and a magnetic field system capable of varying the distribution or intensity of a magnetic field impressed on the working material. When the working material produces heat on the high temperature side, heat exchange is performed by boiling heat transfer through a refrigerant on the high temperature side; when the working material absorbs heat on the low temperature side, heat exchange is performed by condensation heat transfer through a refrigerant on the low temperature side.

Abstract: A novel composite superconductor includes a superconducting material and a normal conducting material. The composite superconductor has a number of closely spaced grooves on a surface being in contact with a refrigerant, and a number of ridges spaced apart from each other by the grooves and having acutely tapered ends. The surfaces of the grooves and the ridges are coated with a thin film of metal or its compound having higher heat resistance than that of the surface of the composite superconductor. Consequently, a high critical heat flux in film boiling and a high cooling capability can be provided, thereby making it possible to decrease the sectional area of the normal conducting material, to increase the effective current density and to miniaturize the size of a magnet.

Abstract: A superconductor has a coolant passage in the internal portion to cool itself by flowing a coolant in the coolant passage. The coolant passage is formed in the stabilizing material portion in such a manner that the inner wall of the coolant passage is wave-shaped, proportion of the cross-sectional area of the coolant passage occupied in the cross-section of the superconductor is 4-22 percent, and a ratio of the circumferential length to the cross-sectional area of the coolant passage is greater 25 (cm.sup.-1).