Abstract: A superconducting magnet apparatus includes a superconducting coil, a persistent current switch, a cryostat, an external resistance element that attenuates energy accumulated in the superconducting coil when the superconducting coil is demagnetized, an external power supply capable of energizing a reverse current of a persistent current to the superconducting coil, and a circuit breaker capable of freely cutting off energization between the external power supply and the superconducting coil. A method for demagnetizing a superconducting magnet includes causing the reverse current of the persistent current to flow from the external power supply, and switching the persistent current switch to an off-state and switching the circuit breaker to an off-state, and demagnetizing the superconducting magnet by causing a current flowing through the superconducting coil to flow to an external resistance element when the amount of current flowing through the persistent current switch decreases.

Abstract: Provided are: a superconducting wire rod in which the non-uniform deformation of the shape of an MgB2 core material has been controlled; a superconducting coil; a magnetic generator; and a method for producing a superconducting wire rod. A superconducting wire rod (100A) according to the present invention comprises: a center material (106) of which at least the outer circumferential surface is formed of a metal that does not react with Mg; a plurality of single-core wires (103) disposed around the center material (106), each of the single-core wires having an MgB2 superconductor core material (101) coated with a first coating material (102) made of a metal that does not react with Mg; and an outer shell material (105) disposed outside the plurality of single-core wires (103), wherein at least the inner circumferential surface of the outer shell material (105) is formed of a metal that does not react with Mg.

Abstract: In the connection portion for a superconducting wire, a plurality of superconducting wires are integrated by a sintered body containing MgB2, end portions of the superconducting wires each having an outer peripheral surface of a superconducting filament exposed are inserted into a container in parallel. The container has an opening having a diameter larger than a wire diameter of the superconducting wires on at least one side in a longitudinal direction of the superconducting wires, and the sintered body is in contact with the outer peripheral surfaces of the superconducting filaments. The method for connecting a superconducting wire includes: exposing the outer peripheral surfaces of the superconducting filaments; inserting the superconducting wires into the container; filling the container with a raw material; and heat-treating the raw material to generate the sintered body. The raw material is pressurized in parallel to the longitudinal direction of the superconducting wires and then heat-treated.

Abstract: The purpose of the present invention is to provide a method for causing sufficient deformation in precursor particles even when a soft high-purity metal is used for an outer layer material in mechanical milling, and manufacturing an MgB2 superconducting wire. A method for manufacturing an MgB2 superconducting wire in which an MgB2 filament is covered by an outer layer material, the method comprising: subjecting magnesium powder and boron powder to a shock that is insufficient for MgB2 to be clearly produced, and producing precursor particles in which boron particles are dispersed inside a magnesium matrix; filling a metal tub with the precursor particles; processing the metal tube filled with precursor particles to form a wire; and heat-treating the wire to synthesize the MgB2; wherein the method is characterized in that a portion of the wire-drawing step includes swaging.

Abstract: The present invention is intended to increase the critical current density of a wire rod having a shape with good symmetry such as a round wire or a square wire by making use of mechanical milling method. The production method of the present invention for the MgB2 superconducting wire rod comprises a mixing process of preparing a powder by adding a solid organic compound to a magnesium powder and a boron powder and then applying an impact to the powder to prepare a mixture of the powder in which boron particles are dispersed inside magnesium particles, a filling process of filling a metal tube with the mixture, an elongation process of elongating the metal tube filled with the mixture and a heat treatment process of heat-treating the metal tube to synthesize MgB2.

Abstract: A superconducting wire comprises a MgB2 filament, a base material, a high-thermal expansion metal, and a stabilizing material. The high-thermal expansion metal is a metal (for example, stainless steel) having a higher thermal expansion coefficient at room temperature than the MgB2 and the base material (for example, iron or niobium). The manufacturing method includes a step of packing a mixed powder in a first metal pipe, a step of performing wire-drawing on the first metal pipe formed of the metal to be the base material, a step of producing a composite wire by accommodating the first metal pipe in a second metal pipe formed of the high-thermal expansion metal and the stabilizing material, a step of performing wire-drawing on the composite wire, and a step of performing heat treatment.

Abstract: The following two problems arise when carbon is added to a starting material powder in the process of production of an MgB2 superconductor: (1) an impurity phase increases; and (2) the degree of substitution of carbon at boron sites is spatially non-uniform. This superconductor production method comprises: a mixing step of mixing a starting material powder and an additive; and a heat treatment step of heat-treating the mixture prepared in the mixing step. The starting material powder is MgB2 powder or a mixed powder of magnesium and boron, and the additive is an Mg—B—C compound containing three elements of magnesium, boron and carbon.

Abstract: The present invention addresses a problem of providing an MgB2 wire material having a small reversible bending radius, a superconducting coil using the same, and an MRI without lowering a critical current value and a critical current density of the MgB2 wire material to an extreme. To solve the problem, provided are a superconducting wire having a plurality of MgB2 strands and a first base metal, a superconducting coil using the same, and an MRI, the superconducting wire being characterized in that in a cross section orthogonal to a wire longitudinal direction, a center point of an area surrounded by the plurality of MgB2 strands and a center axis of a cross section of the superconducting wire are disposed in separated positions.

Abstract: A superconducting wire connector includes superconducting wires and a sintered body containing MgB2. The superconducting wires are connected by the sintered body. At least one of the superconducting wires includes a superconducting core having a first outer surface. The sintered body is in contact with the first outer surface. A method of connecting superconducting wires by a sintered body containing MgB2 includes exposing a superconducting core of at least one of the superconducting wires by removing a portion, positioned in the middle in a longitudinal direction of the at least one of the superconducting wires, of a metal sheath disposed around the superconducting core, disposing the at least one of the superconducting wires through a container, filling the container with a raw material of MgB2, and forming the sintered body being in contact with an outer surface of the superconducting core by sintering the raw material filled in the container.

Abstract: Provided are: a superconducting wire rod in which the non-uniform deformation of the shape of an MgB2 core material has been controlled; a superconducting coil; a magnetic generator; and a method for producing a superconducting wire rod. A superconducting wire rod (100A) according to the present invention comprises: a center material (106) of which at least the outer circumferential surface is formed of a metal that does not react with Mg; a plurality of single-core wires (103) disposed around the center material (106), each of the single-core wires having an MgB2 superconductor core material (101) coated with a first coating material (102) made of a metal that does not react with Mg; and an outer shell material (105) disposed outside the plurality of single-core wires (103), wherein at least the inner circumferential surface of the outer shell material (105) is formed of a metal that does not react with Mg.

Abstract: The purpose of the present invention is to provide a method for causing sufficient deformation in precursor particles even when a soft high-purity metal is used for an outer layer material in mechanical milling, and manufacturing an MgB2 superconducting wire. A method for manufacturing an MgB2 superconducting wire in which an MgB2 filament is covered by an outer layer material, the method comprising: subjecting magnesium powder and boron powder to a shock that is insufficient for MgB2 to be clearly produced, and producing precursor particles in which boron particles are dispersed inside a magnesium matrix; filling a metal tub with the precursor particles; processing the metal tube filled with precursor particles to form a wire; and heat-treating the wire to synthesize the MgB2; wherein the method is characterized in that a portion of the wire-drawing step includes swaging.

Abstract: Provided is a high-performance persistent current switch that is provided with a superconducting coil in which a decrease of a critical current or a critical magnetic field is suppressed. A means for solving the problem is as follows. A persistent current switch provided with a superconducting coil in a switch unit. A superconducting coil 5 includes a winding portion 53 which is formed using a superconductor thin film formed on an outer circumferential face of a base member 50. The winding portion 53 includes a first winding portion 51 and a second winding portion 52 which are formed in a double helical shape to be parallel to each other. A terminating end portion 51b of the first winding portion 51 and a starting end portion 52a of the second winding portion 52, which are adjacent to each other, are connected to each other.

Abstract: The present invention is intended to increase the critical current density of a wire rod having a shape with good symmetry such as a round wire or a square wire by making use of mechanical milling method. The production method of the present invention for the MgB2 superconducting wire rod comprises a mixing process of preparing a powder by adding a solid organic compound to a magnesium powder and a boron powder and then applying an impact to the powder to prepare a mixture of the powder in which boron particles are dispersed inside magnesium particles, a filling process of filling a metal tube with the mixture, an elongation process of elongating the metal tube filled with the mixture and a heat treatment process of heat-treating the metal tube to synthesize MgB2.

Abstract: The following two problems arise when carbon is added to a starting material powder in the process of production of an MgB2 superconductor: (1) an impurity phase increases; and (2) the degree of substitution of carbon at boron sites is spatially non-uniform. This superconductor production method comprises: a mixing step of mixing a starting material powder and an additive; and a heat treatment step of heat-treating the mixture prepared in the mixing step. The starting material powder is MgB2 powder or a mixed powder of magnesium and boron, and the additive is an Mg—B—C compound containing three elements of magnesium, boron and carbon.

Abstract: A sealed structural body has an internal space and is made of glass, wherein at least a part of a boundary between the internal space of the sealed structural body and the outside is separated by a sealing material containing a metal material and a lead-free oxide glass. The lead-free oxide glass contains at least one of element Ag or P, Te, and V.

Abstract: There is disclosed a heat-insulating member including a pair of substrates and an airtight sealing part, in which the airtight sealing part is formed in an outer peripheral part between the pair of substrates to form a space between the pair of substrates, the space being in a vacuum or reduced pressure state, a sealing material that forms the airtight sealing part includes a low-melting glass, and the low-melting glass contains a vanadium oxide, barium oxide, phosphorus oxide, and tungsten oxide, in which the following two relational expressions are satisfied in terms of oxide contents: V2O5+BaO+P2O5+WO3?90 and V2O5>BaO>P2O5>WO3 (wherein unit: mol %). Thereby, influence on environmental impact can be reduced and maintenance of airtightness and an improvement in acid resistance can be achieved.

Abstract: The present invention addresses the problem of providing a wire material capable of ensuring high critical current density, regardless of the cross-sectional shape thereof. This super-conducting wire material is equipped with an MgB2 filament, the number density of cavities having a major axis of 10 ?m or higher in a longitudinal cross-section of the superconducting wire material is in the range of 5-500 mm?2, and the average value of the angle formed between the major axis of the cavities and the axis of the wire material is 60 degrees or more.

Abstract: A heat-dissipating structure is formed by bonding a first member and a second member, each being any of a metal, ceramic, and semiconductor, via a die bonding member; or a semiconductor module formed by bonding a semiconductor chip, a metal wire, a ceramic insulating substrate, and a heat-dissipating base substrate including metal, with a die bonding member interposed between each. At least one of the die bonding members includes a lead-free low-melting-point glass composition and metal particles. The lead-free low-melting-point glass composition accounts for 78 mol % or more in terms of the total of the oxides V2O5, TeO2, and Ag2O serving as main ingredients. The content of each of TeO2 and Ag2O is 1 to 2 times the content of V2O5, and at least one of BaO, WO3, and P2O5 is included as accessory ingredients, and at least one of Y2O3, La2O3, and Al2O3 is included as additional ingredients.

Abstract: An MgB2 superconducting wire includes a core containing MgB2 and a metal sheath which surrounds the core. The core includes at least a first MgB2 core positioned on the center side, and a second MgB2 core positioned outside the first MgB2 core, and the density of the second MgB2 core is lower than the density of the first MgB2 core.

Abstract: An electronic component has an organic member between two transparent substrates, in which outer peripheral portions of the two transparent substrates are bonded by a sealing material containing low melting glass. The low melting glass contains vanadium oxide, tellurium oxide, iron oxide and phosphoric acid, and satisfies the following relations (1) and (2) in terms of oxides. The sealing material is formed of a sealing material paste which contains the low melting glass, a resin binder and a solvent, the low melting glass containing vanadium oxide, tellurium oxide, iron oxide and phosphoric acid, and satisfies the following relations (1) and (2) in terms of the oxides. Thereby, thermal damages to an organic element or an organic material contained in the electronic component can be reduced and an electronic component having a glass bonding layer of high reliability can be produced efficiently.