Abstract: Lumped element electrical components, such as inductors and capacitors, are formed to include high temperature superconducting materials. In the preferred embodiment, thin film epitaxial high temperature superconductors are patterned to form capacitors and inductors on low loss substrates. Preferably, a ground plane is formed on the back side of the substrate, most preferably being formed of high temperature superconducting material, or other highly conductive materials such as gold or copper. Various advantageous structures include a planar spiral structure, a zig-zag serpentine structure, a single coil structure and a double coil structure. Single layer and multilayer structures are included. Improved narrow bandpass filters and high Q resonator structures are formed.

Abstract: Double pancake coils include a pair of pancake coils of different outer dimensions, and are wound from the same continuous length of superconducting wire. The double pancake coils are coaxially positioned and electrically interconnected along a longitudinal axis to provide a multi-coil superconducting magnetic coil assembly. Each of the double pancakes has at least one of its pancake coils electrically connected to at least another pancake coil of an adjacent double pancake coil having substantially the same outer dimension. The electrical connections between adjacent pancake coils are provided with relatively straight or "unbent" segments of superconducting wire even though the outer dimension profile of the superconducting magnetic coil assembly along its longitudinal axis varies.

Abstract: A method of producing a high temperature long length coil of superconductor wire or tape having improved critical current densities by utilizing an in-line pressing operation to heal the microcracks in the tape or wire which were introduced in rolling and coiling operations. The material can be Bismuth-2223, Bismuth 2212, Thallium-1234 or any other high temperature superconducting material. In the case of the Bismuth-2223, an improved "powder-in-tube" processing operation is provided to utilize excess bismuth, calcium, and copper in the initial composition material, and forming a partially developed Bi-2223 phase in the precursor powder introduced into the silver tubes. The final product has a 90-100% Bi-2223 phase with fine dispersions of secondary phases, to provide improved flux pinning thereby improving the critical current density of the material.

Abstract: A flux transformer comprises a pickup coil 1, an input coil 2 and a pair of lines 3, 4. The line 4 contains a bridge part 4a intersecting the input coil 2. The pickup coil 1, input coil 2 and a pair of lines 3, 4 are formed of a first and a second oxide superconducting thin films 11, 13. Furthermore, the flux transformer comprises a non-superconducting thin film 12. The non-superconducting thin film 12 is disposed between the first and the second oxide superconducting thin films 11, 13 and is located in a domain wherein the line 4 intersects the input coil 2. A pattern of the first oxide superconducting thin film 11 corresponds to the pickup coil 1, the input coil 2 and the lines 3,4 except the bridge part 4a. The pattern of the second oxide superconducting thin film 13 corresponds to the input coil 2 except the domain where the non-superconducting thin film exits, the pickup coil 1 and the lines 3,4.

Abstract: A method of preparing a superconducting oxide by combining the metallic elements of the oxide to form an alloy, followed by oxidation of the alloy to form the oxide. Superconducting oxide-metal composites are prepared in which a noble metal phase intimately mixed with the oxide phase results in improved mechanical properties. The superconducting oxides and oxide-metal composites are provided in a variety of useful forms.

Abstract: A superconducting magnet coil is produced by winding a superconducting wire to form a coil; impregnating the coil with a curable resin composition of low viscosity which contains for example at least one epoxy resin selected from the group consisting of diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F and diglycidyl ether of bisphenol AF, all having a number-average molecular weight of 350-1,000, a flexibilizer and a curing catalyst, to obtain a curable-resin composition-impregnated coil; and heating the curable-resin-composition-impregnated coil to cure the composition.

Abstract: A process for manufacturing superconducting magnetic coils from strain-tolerant, superconducting multi-filament composite conductors is described. The method involves winding the precursor to a multi-filament composite conductor and an insulating material or its precursor around a mandrel in order to form a coil, and then exposing the coil to high temperatures and an oxidizing environment. The insulating material or its precursor is chosen to permit exposure of the superconductor precursor filaments to the oxidizing environment, and to encase the matrix-forming material enclosing the filaments, which is reversibly weakened during processing.

Abstract: A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

Abstract: A high temperature superconducting coil includes an oxide superconducting wire 2 wound in a coil, a container 3 for accommodating the superconducting wire 2, and a filling resin portion 4 for fixing the superconducting wire 2 in the container 3 by being injected into the container 3 and then cured.

Abstract: A biomagnetometer includes a magnetic field sensor unit having a magnetic field pickup coil. A vessel contains the sensor unit. The vessel includes a flexible contact face with the magnetic field sensor unit mounted in the interior of the vessel adjacent to the flexible contact face. Insulation at the flexible contact face of the vessel prevents excessive heat flow through the flexible contact face. Pickup units using this structure can be connected together into flexible or rigid arrays. In operation, the pickup coil is cooled to a temperature of less than its superconducting transition temperature. A detector measures the magnitude of magnetic fields sensed by the sensor unit.

Abstract: A superconducting magnet module comprises an alternate series of abutting and coaxially aligned first and second superconductive magnet modules. The first magnet module includes a first substrate having opposed first and second faces and a bore filled with a superconductive material extending between the first and second faces. The first face is formed of an electrically conductive material and the second face is formed of an electrically insulating material. A first spiral track of the superconductive material is formed on the first face in electrical and thermal contact with the electrically conductive material. The first spiral track is melt fused to the superconductive material in the bore. The second magnet module includes a second substrate having opposed third and fourth faces. The third face is formed of an electrically conductive material and the fourth face is formed of the electrically insulating material.

Abstract: A beam member which is installed at diametral portion in a ring shape superconducting coil container for supporting hoop stress of the coil, or a portion of radiant heat shield covering the beam member, is partly or entirely composed of electrical insulators or high resistivity materials. In accordance with the above composition, eddy current which is generated in the coil container when the superconducting coil container crosses magnetic field caused by eddy current which is generated in the radiant heat shield when the radiant heat shield crosses strong magnetic field caused by the superconducting coils with relative vibration of the radiant heat shield to the superconducting coil by a dynamic cause can be suppressed. Accordingly, heat generation in the superconducting coil container can be reduced, and consequently, generation of quenching can be prevented.

Abstract: A coil configuration includes at least one superconducting coil having an associated coil surface and a conductor containing superconducting filaments and being wound substantially on the coil surface. The conductor has a longitudinal axis and has a respective transversal axis oriented approximately perpendicular to the coil surface at each point along the longitudinal axis. The conductor has a cross section being extended along the transversal axis at each of the points along the longitudinal axis. The conductor has two ends protruding from the at least one coil. At least one of the ends has a twist in the vicinity of the at least one coil. The transversal axis is approximately parallel to the coil surface downstream of the twist.

Abstract: A superconducting magnet coil contains a coil of superconducting wire and a cured product of a curable resin composition with which the coil has been impregnated, the cured product having a thermal shrinkage factor of 1.5-0.3%, preferably 1.0-0.3%, when cooled from the glass transition temperature to 4.2K, a bend-breaking strain of 2.9-3.9%, preferably 3.2-3.9%, at 4.2K and a modulus of 500-1,000 kg/mm.sup.2 at 4.2K, or undergoing a thermal stress of 0-10 kg/mm.sup.2 when cooled from the glass transition temperature to 4.2K and resisting to quench during superconducting operation.

Abstract: In the case of high-temperature superconductors (6) which are used as inductive current limiters, unless any special precautionary measure is taken, there is a risk that short-circuit currents can lead to local stress centers and hot spots, and to local destruction of the high-temperature superconductor. In order to avoid this, a hollow cylinder (SL) of the high-temperature superconductor (6) is coated with a 1 .mu.m thick conductive-silver layer (E1). A second 10 .mu.m thick metal layer of foil made of silver or aluminum can be deposited thereon. In order to reduce or to avoid tensile stresses in the ceramic of the hollow cylinder (SL) made of a high-temperature superconductor, and in order to reduce the electrical contact resistance of the metal layers, this hollow cylinder (SL) has a mechanical reinforcing element (7), made of an elastic steel wire, wound around it, at room temperature, under tensile stress.

Abstract: An oxide superconductive wire is provided by, for example, forming an oxide superconductive layer on a tape-type flexible base. A preliminary compressive strain is applied to the oxide superconductive layer in the longitudinal direction. The remaining strain can be provided by using a base having thermal expansion coefficient larger than that of the oxide superconductive layer and by cooling the same after heat treatment, due to contraction of the base. Since the preliminary compressive strain is applied to the oxide superconductive layer, degradation of superconductivity of the oxide superconductive layer can be suppressed even if the oxide superconductive wire is bent in any direction, compared with the wire without such strain. Therefore, the oxide superconductive wire can be coiled, for example, without much degrading the superconductivity.

Abstract: A method for producing a superconducting copper oxide based helical resonator coil exhibiting improved quality factor, Q. A copper oxide based superconductor powder is mixed with a binder melt at about 45-65% solids by volume. The binder is an RCOOR' ester wax with R and R' each a long chain hydrocarbon group of at least 6 carbons. The ester wax has a melting point of about 40.degree.-100.degree. C. and a viscosity of about 94-2000 centipoise at its melting point. The binder/powder mixture is extruded and wrapped around a mandrel to form a helical coil. The coil is embedded in a setter powder and heated in an oxidizing atmosphere at up to about 2.degree. C./min to about 450.degree.-650.degree. C., and held for a time sufficient to remove the binder. The coil is then heated in the oxidizing atmosphere at up to about 3.degree. C./min to at least about 920.degree. C., and held at about 920.degree.-990.degree. C. for a time sufficient to achieve a density of at least about 93% of theoretical density.

Abstract: Electrical energy is transferred or switched by selectively holding off the coupling of a magnetic field to a secondary inductive element (a coil) through a path which contains a high temperature superconductive element (HTS) which is capable of holding off the field when in its superconductive state notwithstanding that it is a high energy magnetic field. The HTS operates to hold off the magnetic field in accordance with the flux exclusion effect. When the HTS element is driven normal by heating with a laser pulse, the flux passes through the element and couples the field to the secondary, which may be connected to a load. A primary coil of superconducting material around the secondary coil can provide superconducting magnetic energy storage. The primary field is held off by HTS elements in the flux path to opposite ends of the secondary coil. These elements may be driven normal by laser pulses to transfer the stored magnetic energy to a load.

Abstract: A device having cores of metal oxide ceramic (for example, Y-Ba-Cu-O) for limiting a short circuit current in power supply systems. The concept provides that a choke core, when operated at a rated current, is superconductive and its shielding currents keep the resulting inductance in the choke at a low level. In the event of an overload, the winding of the choke generates a correspondingly high magnetic field in the core which puts the core into the normally conducting state. This causes the shielding currents to disappear in connection with a rise in the resulting inductance, thus limiting the current. In order to realize a particularly high inductance in the normally conductive case, the superconductive choke core may be made hollow and may be filled at least in part with a ferromagnetic material.

Abstract: A superconducting coil apparatus comprises a cryostat, a superconducting coil body contained in a cryostat and including a surface portion of an epoxy resin layer, and an interposing member interposed between the resin layer of the superconducting coil body and the cryostat and including a block with a through-hole, a thermal barrier member and a friction-reducing member interposed between the block and the heat barrier member. The thickness of that portion of the surface portion of the superconducting coil body, which contacts the interposing member, is set in a range of 0.4 mm to 3.5 mm, and the thickness of the other portion of the surface portion is set to less than 0.4 mm.

Abstract: An oxide superconductive wire is provided by, for example, forming an oxide superconductive layer on a tape-type flexible base. A preliminary compressive strain is applied to the oxide superconductive layer in the longitudinal direction. The remaining strain can be provided by using a base having thermal expansion coefficient larger than that of the oxide superconductive layer and by cooling the same after heat treatment, due to contraction of the base. Since the preliminary compressive strain is applied to the oxide superconductive layer, degradation of superconductivity of the oxide superconductive layer can be suppressed even if the oxide superconductive wire is bent in any direction, compared with the wire without such strain. Therefore, the oxide superconductive wire can be coiled, for example, without much degrading the superconductivity.

Abstract: High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field.

Abstract: The present invention is related to a superconductive ceramic wire and a method for making same. According to the first aspect of the invention, there is provided a method for making a superconductive ceramic wire, the method comprising the steps of: (a) preparing a superconductive porous ceramics; (b) depositing lead in the pores of the ceramics; (c) covering the lead-depositted ceramics with a metal; and (d) extending the metal-clad and lead-deposited ceramics. According to the second aspect of the invention, there is provided a superconductive ceramic wire which is obtained by: (a) preparing a superconductive porous ceramics; (b) depositing lead in the pores of the ceramics; (c) covering the lead-depositted ceramics with a metal; and (d) extending the metal-clad lead-depositted ceramics.

Abstract: Improvement in a method for producing a superconducting wire of compound oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-.delta. by the steps comprising filling a metal pipe with a material powder, carrying out plastic deformation of the metal pipe and then subjecting the material powder in deformed metal pipe to sintering operation. The present invention is characterized in that the heat-treatment is carried out in the coexist of silver oxide: Ag.sub.2 O placed inside the metal pipe.

Abstract: A thin-film superconducting LC network comprising a dielectric substrate having first and second oppositely disposed surfaces, a first thin-film superconducting conductor on one of the surfaces defining an inductor, second and third thin-film superconducting conductors on said first and second surfaces, respectively, said second and third conductors opposing each other and having at least a portion of the dielectric substrate therebetween to form a capacitor, and thin-film superconducting conductor for interconnecting the inductor and capacitor to form a desired LC network. In one embodiment, the substrate between the second and third conductors have a thickness less than the thickness of the substrate between the first conductor and it oppositely disposed surface. In another embodiment, the inductor is defined by a plurality of closely spaced adjacent turns and a channel is disposed within the substrate between the adjacent turns.

Abstract: A method to form a superconducting wire or ribbon contains the steps: (1) forming ceramic powder, (2) forming pellets from the powder, (3) inserting the pellets in a metal sheath, (4) reducing the cross-section of the sheathed pellets to form a composite, (5) sealing the composite in a deformable container, (6) hot isostatically pressing the composite at a temperature over 600.degree. C., where the temperature is close to or just above the melting point of the core, and (7) annealing the pressed composite in a source of oxygen at a temperature from 770.degree. C. to 870.degree. C. for at least 40 hours.

Abstract: A magnet assembly suitable for use in magnetic resonance imaging has a first superconducting coil assembly for generating a first magnetic field and a second superconducting coil assembly for generating a second magnetic field. The first and second superconducting coil assemblies are connected in series and each generate magnetic fields whose corresponding components are of substantially the same order of magnitude. The assemblies are arranged so that a resultant, uniform magnetic field is generated in a working volume, and the second magnetic field substantially opposes the first magnetic field externally of the magnet assembly. The resultant magnetic field prevailing externally of the magnet assembly is maintained within preset limits during normal operation of the assembly in which the current in the superconducting coils is substantially constant.

Abstract: A superconducting coil is disclosed. A plurality of coils made of oxide superconducting materials are formed on the respective surfaces of substrates, and the adjacent coils mounted on the substrates are connected by conductors to form one coil. Since the coil consists mainly of oxide superconductor, liquid nitrogen can be used to cool at a temperature less than Tc the coil which is energized in order to generate a magnetic field. Therefore it costs less to generate a magnetic field by the coil than by the conventional coils made of metallic superconductors. In addition, the coil is mechanically strong.

Abstract: A method for making superconducting ceramic filaments by joining the ceramic to a normal conducting metal in such a way that minimal mechanical working, drawing, or extrusion is needed to arrive at a fine filamentary shape.

Abstract: A laminated ceramic superconductor which comprises at least two layers of ceramic superconductor and a stabilizing metal layer interposed between said ceramic superconductor layers, which has improved flexibility and increased critical current density.

Abstract: A device for inductive current limiting of an alternating current consisting of an induction coil (2), which includes at least one winding and through which current flows, a body (3) made of a ceramic high-temperature superconductor arranged concentrically to the latter and having a centrosymmetrical form which is hollow in the interior, and having located in the interior of said body (3) a concentrically arranged core (4) made of a soft magnetic material of high permeability. In normal operation (rated current), the superconductivity of the body (3) is effective and impedance of the induction coil (2) is very low. With overcurrent (mains short-circuit) the superconductivity disappears and the impedance of the induction coil (2) reaches its maximum, current-limiting value.

Abstract: A novel construction of a superconductive coil system, having sufficient coupling strength and stiffness and being easy to assemble, is disclosed. A coil retainer of a stiffened cylindrical shell is divided into two parts for receiving coils and spacers. The inner circumference sides of the adjoining portions of the two parts form a dividing surface consisting of a plane extending longitudinally and are coupled with bolts having their axes directed in the circumferential direction. The outer circumference sides of the same adjoining portions form comb teeth meshed with each other and keyways extending longitudinally along the outer surface of the same comb teeth, and are coupled by keys inserted into the keyways and having their axes directed in the longitudinal direction.

Abstract: Improvement in a method for producing a sintered elongated article by the steps comprising filling a metal pipe with a material powder, carrying out plastic deformation of the metal pipe and then subjecting the material powder in deformed metal pipe to sintering. In the invention, a netting of metallic wire (1) whose melting point is higher than a melting point of the material powder (3) is arranged around the metal pipe (2) before the sintering.

Abstract: Powder or lengths of ceramic or metallic superconductor ceramic compositions are loaded into lengths of metal tubing. Mechanical reduction of filled tubing is facilitated by use of elevated temperatures and intermittent heat treatments as required. Rolling to a flattened cross section aids bending to the final device configurations and subsequent hot-isostatic-pressing. Hot-isostatic-pressing steps (1) close defects, including voids, cracks and joints and improve microstructure, and (2) join tested wire lengths to produce a superconductor length in the final configuration. Encapsulation of the superconductor is completed and assured with metal sleeves and solder or glass.

Abstract: An electromagnetic resonator has two or more non-intersecting, substantially overlapping surfaces of approximately similar size and shape separated from one another by a distance which is small in comparison to the physical extent of the surfaces. One or more substantially non-intersecting, electrically conductive paths cover substantial portions of each surface. The widths of the paths are substantially smaller than the physical extent of the surfaces. No path on any one of the surfaces is electrically connected to a path on any of the other surfaces. The conductive paths are oriented such that, for each of the surfaces, macroscopic current flows, with respect to the surfaces, in a direction other than the direction in which microscopic current flows in the paths.

Abstract: A method and flux pump for inducing electrical energy from superconducting and ferromagnetic material comprising initially magnetizing said ferromagnetic material, and applying heat to raise the ferromagnetic material above its magnetic transition temperature, so as to cause a loss of magnetization and induce a current in a superconducting circuit.

Abstract: A method of manufacturing a superconductive coil by means of explosive compaction. A wire formed of silver having a superconductive oxide powder charged therein is formed into a coil. The coil is placed within a cylindrical vessel, into which a pressure medium is charged. Explosive compaction is carried out to cause the compaction of the coil through the cylindrical vessel and the pressure medium and hence densify the coil. The compacted coil is heat-treated in an air or oxygen atmosphere. The resulting superconductive coil possesses high critical electric current density. Advantageously, the coil is mounted on a mandrel axially extending therethrough, and placed together with the mandrel into the cylindrical vessel, before explosive compaction.

Abstract: A superconducting ceramic film is deposited on a substrate sputtering. In virtue of the low thermal conductivity of ceramic, a laser beam is radiated to the ceramic film in order to remove the irradiated portion by sublimation and produce a pattern on the ceramic film.

Abstract: An electroacoustic transducer comprises a terminal (1-1'), a voice coil (2) coupled to the terminal, and a diaphragm (4). The transducer further comprises an element (other than the voice coil) made of a superconducting material which cooperates with the voice coil (2) to provide electromechanical conversion of an electric signal appearing at the terminal (1-1') into vibrations of the diaphragm, or vice versa.

Abstract: A closed flexible superconductive ribbon, is made to confine magnetic flux nd which is thereafter elongated and selectively twisted to form a desired type of magnetic field. The shape of the twist is varied for the particular application. A helical field source for twister type geometries, for example, can be implemented by winding the stretched superconducting loop around a cylindrical tube. In another embodiment, the superconductive ribbon is twisted into two halves, one of which is rotated 180.degree. with respect to the other. In such a configuration, two fields exist which are mutually opposite to each other.