32 results about "Self field" patented technology

The invention discloses a superconducting stack soldering method for a high-temperature superconducting current lead wire and a mold thereof; superconducting tapes to be soldered and soldering ribbons are alternately arranged in a mold cavity which is made of metal materials with good thermal conductivity; a mold core and a counterweight are pressed on the superconducting tapes, the mold is heated to the soldering temperature under the vacuum condition, the temperature is kept for 10-15 minutes, and then the mold is rapidly cooled to the solidification point of soldering filler metals to complete the soldering. The critical current of the low-heat conductivity high-temperature superconducting tapes under a 77K self-field is only 100-120A which is much less than the thousands to tens of thousands of amperes of operating current of a large superconducting magnet, so that the superconducting tapes can be used by soldering into a stack. The price of the bismuth-based superconducting tape which takes Ag-5.3wt% Au alloy as a substrate is 5-6 times than the price of the ordinary bismuth-based superconducting tape; while the offer of a superconducting stack of foreign high-temperature superconducting companies is almost doubled again. The method and the mold for soldering the superconducting stack can ensure that the current carrying performance is not deteriorated, the longitudinal heat leakage is not increased, the soldering among the superconducting tapes is uniform and the requirements on the resistance performance in a low layer can be met.

A superconducting article is disclosed, including a substrate and a chemical vapor deposited thin film superconducting layer overlying the substrate, the superconducting layer having a critical current not less than about 100 A / cm width at 77K and self field. The superconducting article may be a tape, multiple tapes, or a power device, such as a power cable, power generator, or power transformer. Also disclosed are methods for manufacturing same and methods for using same.

Nanometer-sized non-superconducting particulates in superconductive REBCO films, where RE is a rare earth metal, for flux pinning enhancement and a method of forming are disclosed. A target with a second phase material sector portion and a superconductive material portion is used in a pulse laser deposition process to form films on substrates according to the present invention. The films consist of 10-20 nm-sized precipitates. In a 0.5 μm thick film, a transport critical current density (Jc)>3 MA / cm2 at 77K in self-field was measured. In one embodiment, magnetization Jc at 77 K and 65K showed significant improvements in a composite YBCO films with fine precipitates produced according to the present invention as compared to non-doped (standard) YBCO films (>10 times increase at 9 T, 65 K).

The invention discloses a vacuum welding device and a method for a high-temperature superconducting stack used for a large-sized magnet current lead. The vacuum welding device comprises an independent heating vacuum chamber, a cold base and a hot base, wherein the cold base and the hot base are arranged in the vacuum chamber. The interior of the vacuum chamber also comprises a movable welding die and a moving part which can be used for enabling the die to move in the vacuum chamber. After the welding die is contacted with the hot base through the moving part and heated to specified temperature, the welding die is separated from the hot base and is contacted with the cold base to realize rapid cooling. According to the vacuum welding device and the welding method, the superconducting stack is high in density, welding effect and current-carrying capability; and 7-stacked critical current measured under self-fields at 77K can reach 70 percent of the critical current of an original strip, and 4-stacked critical current exceeds the 80 percent critical current of the original strip. The superconducting stack can be applied to the large-sized magnet current lead as a discharge current conductor, and therefore, the effect of reducing heat emission and heat transfer of the lead is achieved, the cooling power is saved, and the operating environment of a magnet is improved.

A method and an apparatus for interfering with pathological cells survival processes, i.e. inducing directly or indirectly apoptosis, on living pathological cells, by using magnetic fields without adversely affecting normal cells. Static (S) and extremely low frequency (ELF) magnetic fields are used having low intensity comprised between 1 and 100 mT, preferably comprised between 1 and 30 mT. In particular SELF fields are used which are different sequences of S and / or ELF fields, i.e. S fields followed by ELF fields, ELF fields followed by S fields, S and ELF field together, as well as the presence of S or ELF fields alone, said ELF fields having a field frequency comprised between 1 and 1000 Hz. An apparatus for carrying out the method comprises means for generating static magnetic (S) fields crossing a working environment and / or means for generating electromagnetic extremely low frequency (ELF) fields over the working environment in addition to the S fields. Means are provided for modulating the S fields associated to the S fields generating means and varying the intensity of the S fields from 1 to 100 mT, preferably between 1 to 30 mT according to a predetermined function. Means may also be provided for modulating the ELF fields associated to the ELF fields generating means and imposing to the ELF fields a frequency between 1 and 1000 Hz with intensity comprised between 1 to 100 mT, preferably between 1 and 30 mT according to a predetermined function.

Provided is a surface treatment apparatus which can reduce the energy of an electron beam and simplify a constitution. The surface treatment apparatus 1 is equipped with a mounting stand 3 for mounting almost horizontally a semiconductor wafer W in a vacuum chamber 2, an electron beam irradiation mechanism 6 which is arranged at a ceiling of the vacuum chamber 2 and irradiates the semiconductor wafer W with an electron beam, and a self-field generator 13 arranged between the mounting stand 3 and the electron beam irradiation mechanism 6. The self-field generator 13 is constituted of a plurality of electro static charge boards 13a which are arranged in face to face with each of irradiation windows 6b in the electron beam irradiation mechanism 6. The electro static charge board 13a is a plate-like object, has five slits 13b which passes the electron beam on the facing surface which faces the irradiation windows 6b, and is provided with an internal component 13c constituted of a conductor, an external component 13d constituted of an insulator covering the internal component 13c, and a wire 13e which grounds the internal component 13c.

A superconducting fault current limiter array with a plurality of superconductor elements arranged in a meanding array having an even number of supconductors parallel to each other and arranged in a plane that is parallel to an odd number of the plurality of superconductors, where the odd number of supconductors are parallel to each other and arranged in a plane that is parallel to the even number of the plurality of superconductors, when viewed from a top view. The even number of superconductors are coupled at the upper end to the upper end of the odd number of superconductors. A plurality of lower shunt coils each coupled to the lower end of each of the even number of superconductors and a plurality of upper shunt coils each coupled to the upper end of each of the odd number of superconductors so as to generate a generally orthoganal uniform magnetic field during quenching using only the magenetic field generated by the superconductors.

A power conversion and distribution system. In one embodiment low voltage source components convert a high voltage AC power source to a relatively low voltage supply and provide a direct current output. First superconductor wires carry current from the low voltage source components to a load, and second superconductor wires carry current from the load to the low voltage source components. Individual ones of the first wires are grouped with individual ones of the second wires so that wires connected to carry current in opposite directions are in such sufficiently close proximity that additives of self-fields generated by individual ones of the wires during power transmission result in reduction of the magnetic fringe field generated, thereby increasing the current carrying capacity of the wires.

An improved process for the preparation of oxide superconducting rods. The present invention provides a process for the preparation of oxide superconducting rods. The process includes the steps of a cold isopressing process without addition of binder, particularly thin and those based on Ag-added (Bi,Pb)2 Sr2 Ca2 Cu3 O10+x is disclosed. The main features of the process are the packing of partially preformed oxide superconducting powder obtained from spray drying a nitrate solution of Bi,Pb,Sr,Ca,Cu and Ag in a flexible rubber mould wrapped with a perforated metal sheet and whose inner surface is coated with olive oil, evacuating the packed partially preformed powder to remove trapped air and thereby reduces the defects and improves the subsequent cold isopressing to form rods; immediate cleaning the surface of the said rods so that no trace of olive oil is left; sintering initially the said rod in a silver tube / alumina sager, making silver metal contacts at both ends of the initially sintered rod; finally sintering the assembly of the said rod and both end silver metal contacts. The rods obtained according to these aspects show desired and consistent values of transport current not less than 36 Amp, contact resistance not more than 0.015 μOhm-cm2 at 77K in self field and fracture strength not less than 140 MPa.

A compound winding made of Bi-based and Y-based high-temperature superconducting tapes comprises a Bi-based superconducting coil (1), a Y-based superconducting coil (2), a superconducting coil bobbin (3), axial superconducting coil partitions (4), an upper coil support board (5), a lower coil support board (6) and coil-fixing screws (7). The Bi-based superconducting coil (1) is located in the middle of the compound winding, and the Y-based superconducting coil (2) is located on the end of the compound winding; and the compound winding is mounted in a low-temperature dewar comprising a low-temperature dewar barrel (8) and a low-temperature dewar top cover board (9), and is cooled by directly evaporated liquid nitrogen or the forced flow circulation of liquid nitrogen coupled with a refrigerator. The compound winding is mounted on the low-temperature dewar top cover board (9) through tie rods (10). The compound winding utilizes the characteristics of the Bi-based high-temperature superconducting tape, such as high self-field critical current, and the characteristics of the Y-based high-temperature superconducting tape, such as little critical current decrease in the external field, and can be made into an alternating-current winding and a direct-current winding.

The invention discloses a superconducting stack brazing method and a mold for high-temperature superconducting current leads. The superconducting strips to be welded and the brazing welding strips are alternately put into a mold cavity made of a metal material with good thermal conductivity. The mold core and counterweight are pressed on the superconducting tape. Under vacuum conditions, the mold is heated to the brazing temperature and kept for 10-15 minutes, and then the mold is rapidly cooled to the solidification point of the brazing material to complete the welding. The critical current of the high-temperature superconducting tape with low thermal conductivity is only 100-120A under the self-field of 77K, which is much smaller than the operating current of thousands to tens of thousands of amperes of large superconducting magnets. The superconducting tapes must be welded and stacked for use. The price of the bismuth-based superconducting tape using Ag-5.3wt.% Au alloy as the matrix is ​​5-6 times that of the ordinary bismuth-based superconducting tape; and the price of the superconducting stack of foreign high-temperature superconducting companies is almost doubled. The method of the invention welds the superconducting stack with the mold, which can ensure that the current-carrying performance will not be degraded, the longitudinal heat leakage will not be increased, the welding between the superconducting strips is even, and the performance requirement of low interlayer resistance can be met.

The invention discloses a vacuum welding device and a method for a high-temperature superconducting stack used for a large-sized magnet current lead. The vacuum welding device comprises an independent heating vacuum chamber, a cold base and a hot base, wherein the cold base and the hot base are arranged in the vacuum chamber. The interior of the vacuum chamber also comprises a movable welding die and a moving part which can be used for enabling the die to move in the vacuum chamber. After the welding die is contacted with the hot base through the moving part and heated to specified temperature, the welding die is separated from the hot base and is contacted with the cold base to realize rapid cooling. According to the vacuum welding device and the welding method, the superconducting stack is high in density, welding effect and current-carrying capability; and 7-stacked critical current measured under self-fields at 77K can reach 70 percent of the critical current of an original strip, and 4-stacked critical current exceeds the 80 percent critical current of the original strip. The superconducting stack can be applied to the large-sized magnet current lead as a discharge current conductor, and therefore, the effect of reducing heat emission and heat transfer of the lead is achieved, the cooling power is saved, and the operating environment of a magnet is improved.

The invention provides a large-current superconductor self-field finite element analysis method. The method comprises the steps that a two-dimensional section of a superconductor is built, the finite element method is adopted for performing finite element magnetic field analyzing on the superconductor under the large-current testing condition, magnetic field distribution of the superconductor generated under the large-current operation condition is obtained, the self-field coefficient and position where the maximum magnetic field is generated on the superconductor are obtained, and therefore the appropriate magnitude of a background field for testing of the superconductor is determined and designed. Superconductor self-field analysis under the large-current testing condition is carried out by adopting the finite element method, the self-field two-dimensional distribution of the superconductor can be obtained through more accurate and visual analysis compared with an analysis method, the maximum magnetic field region of the superconductor can be obtained through visual analysis, the self-field coefficient of the conductor is determined, and therefore the reasonable magnitude of the background field for large-current testing of the superchanductor can be designed on the basis of the self-field coefficient.

The invention discloses a preparation method of a LAO (LaAlO3) doped composite YBCO film and belongs to the technical field of preparation of high-temperature superconducting materials. According to the method, organic La salt and Al salt are taken as precursor salts, a precursor solution is prepared with a chemical solution method and then applied to an LAO single crystal substrate with a spin coating method, and then a film is composited to the single crystal surface with a heating processing technology. According to the provided LAO doped composite film, the doping phase LAO can have a coherent boundary with YBCO, and the YBCO structure is not damaged while a pinning defect is introduced. An external solvent is not added, a system is simple, cost-saving, time for a sintering technology is shorter, and epitaxial growth of YBCO is not hindered while the LAO phase is formed. Je of a sample, doped with 5% of LAO, of the composite film under self-field is about 3 times of that of a pure YBCO film and is about 6 times of that of the pure YBCO film under an external field with 77 K and 1.5 T.

The invention discloses a preparation method of a rare earth barium copper oxygen high-temperature superconducting film. The preparation method comprises the following steps: a) weighing rare earth metal salt, barium salt, copper salt and a doping element compound according to a ratio, and dispersing the earth metal salt, the barium salt, the copper salt and the doping element compound into a solvent to obtain a precursor, wherein the doping element compound can generate doping element oxide at 300 to 650 DEG C and under the oxygen atmosphere; b) coating the precursor on a substrate to form a precursor film; c) placing the precursor film into a heat treatment furnace, introducing oxygen, heating the furnace to 300 to 650 DEG C, preserving heat for 0 to 5 hours, and introducing water vapor when the furnace temperature reaches 80 to 120 DEG C until thermal decomposition is finished; d) introducing oxygen nitrogen mixed gas and water vapor, heating the furnace to 700 to 825 DEC C, preserving heat for 20 to 250 DEG C, and stopping introducing the water vapor at the last 1 to 30 percent of time of heat preservation; and e) cooling the furnace to 400 to 500 DEG C and preserving heat for 0 to 240 minutes to obtain a product. According to the rare earth barium copper oxygen high-temperature superconducting film obtained by the preparation method, the thickness is more than 300 nm, the superconduction critical temperature is more than 90 K, and the critical current density at the temperature of 77 K and under the self-field condition is more than 1 mA / cm<2>.