57 results about "Critical magnetic field" patented technology

Electrical connection of superconducting lines can be achieved by using a low-melting point metal, by mechanical contact of superconducting lines or by welding. According to these methods, however, critical current and critical magnetic field at the connection point are low, and stable connection in a superconducting state has been difficult. The present invention solves these problems and provides a structure and method for connecting superconducting lines. The present invention provides high-performance, high-stability connection of superconducting lines through magnesium diboride (MgB₂) powder arranged between superconducting lines.

A samarium and cobalt sintered permanent magnet material comprises, in weight percent, 25-27%wt of samarium, 49-51%wt of cobalt, 5-6.5%wt of copper, 3-3.5%wt of zirconium and 15-18%wt of iron. A preparation method includes the steps: smelting; casting an ingot; absorbing hydrogen for the cast ingot; making powder; performing orientation forming and sintering. In the smelting process, the thickness of a casting mould cavity is decreased, cooling water is filled into the wall of the mould cavity, cooling of the cast ingot is accelerated, element composition segregation is decreased, the production process is stabilized, a dendrite crystal is restrained by adding a zirconium element, hydrogen absorbing is performed for the cast ingot in the smelting process, production steps are saved, and energy consumption is reduced. In the subsequent milling process, the cast ingot absorbed hydrogen is crystallized into particles, the particles fracture along crystal boundaries in the milling process of airflow, the integrality of crystal particles is ensured, the anisotropy of the crystal particles is improved, magnetic powder particles are obtained, particle size distribution is concentrated with the range of 3.5-4.5 micrometers, the sintering temperature needed by the magnetic powder particle of each point of a blank is the same in the later sintering process, the sizes of the sintered crystal particles are the same and uniform, and the performances, particularly, such as residual magnetism Br, maximum magnetic energy product (BH) max and critical magnetic field Hk of a sintered permanent magnet are improved.

The invention belongs to the field of superconducting electrical technology, and particularly relates to a cable-in-conduit conductor based on ReBCO isotropic superconducting strands. In view of the disadvantages of the existing cable-in-conduit conductor prepared from a low-temperature superconductor, such as low critical current density, low critical magnetic field intensity, low operating temperature, small temperature field and poor mechanical property, the invention presents a cable-in-conduit conductor based on ReBCO isotropic superconducting strands. The cable-in-conduit conductor is composed of a center conductor, ReBCO isotropic superconducting strands, a metal sheath, and a cooling channel. The ReBCO isotropic superconducting strands are closely arranged and spirally wound aroundthe center conductor as sub strands. Complete transposition can be realized for the ReBCO isotropic superconducting strands. The cable-in-conduit conductor has the advantages of good critical currentisotropy, high operating temperature, high operating current density, simple production process, suitability for large-scale production, and the like. The application of ReBCO isotropic superconducting strands in nuclear fusion large-scale superconducting magnet coils and other high-energy physical devices is expanded.

The invention provides a preparation method of an iron-based SmFeAsO<1-x>Fx superconducting wire, comprising the steps as follows: a: material preparation: the material is prepared according to the stoichiometry of the iron-based superconducting material SmFeAsO<1-x>Fx (wherein, x is not more than 0.35 and not less than 0.15, the raw materials such as SmAs, Fe, Fe2O3 and FeF3 are weighed, grinded, uniformly mixed, arranged into a Tantalum pipe, fully fixed and compacted; the two ends of the Tantalum pipe are sealed; b: wire preparation: the Tantalum pipe is sheathed into a copper pipe and rotatablely forged; subsequently, the wire with the diameter of 1.8-2.2mm is formed by pulling and drawing; c: burning: the wire is arranged in a quartz pipe and sealed in vacuum and then put into a sintering furnace; under the protection of inert gas, the temperature of the wire is increased to 1150-1170 DEG C at the speed of 100-150 DEG C/hour, the temperature is kept for 36-50 hours and the wire is cooled with the furnace. The method of the invention has the advantages of simple technology and facilitating industrial production, and the compactness, high purification, stable superconducting performance, high superconducting conversion temperature and high critical magnetic field of the prepared iron-based SmFeAsO<1-x>Fx superconducting wire.

The invention discloses a dissymmetrical bottom generatrix and the current configuration method. The current from the cathode soft generatrix distributes in the electrode in the bottom generatrix and side generatrix centered on the Y axis. The current of bottom generatrix and the side generatrix near the flue (right) is higher than that of the aluminium-outputting terminal. The invention, owing to adopting the dissymmetrical configuration of bottom generatrix and the dissymmetrical configuration of the current, can effectively reduce the magnetic field produced by the electrobath, overcome the influence of the critical magnetic field of the slot, make the magnetic field reach the effects of cutting the peak and filling the flat, reduce the grads of the magnetic field and greatly increase the uniformity of the magnet.

The invention relates to a magnetic material, in particular to a magnetic sensitive material with high sensitivity, wherein the magnetic sensitive material contains Fe and the alloy consisting of one or more compositions of Co, B, Si, Nb, V, Mn, Cu, Ni and Cr; the magnetic material is characterized in that the external surface layer is an amorphous shell layer and the inside of the magnetic sensitive material is a composite structure with a nano-crystalline internal core material. The nano-crystalline structure has the advantages of easy magnetization and high permeability in the longitudinal direction and the amorphous structure has the advantages of easy magnetization and high permeability in the ring direction vertical to the longitudinal direction; and the combination of the nano-crystalline structure and the amorphous structure can greatly improve the change rate of impedance and the magnetic field sensitivity, greatly improves the magnetic field sensitivity at a weak magnetic field, has the advantages of low-sensitivity response critical magnetic field (wherein the sensitivity response magnetic field can be less than 5A/m), being sensitive to weak magnetic field without needing a bias field, reducing the power dissipation of a magneto-dependent sensor, low cost, etc., and is a magnetic sensitive material with high cost-performance ratio and high sensitivity.

The invention, which belongs to the field of the magnetic functional material nondestructive testing technology, relates to a rapid nondestructive testing method for a permanent magnet material-based sub-quality product with poor room-temperature and high-temperature performances. The method comprises the following steps that: after saturation magnetizing on a permanent magnet material, the magnetized permanent magnet material is heated to a work temperature of the magnet, a demagnetizing field with the strength of 80% to 100% Hk is applied to the magnet for demagnetization, and cooling is carried out; and a room-temperature open-circuit flux of the magnet after the demagnetization is detected and the sample with the measurement value lower than a set testing standard is a sub-quality product. According to the invention, samples with unqualified indicators like residual magnetism Br, an intrinsic coercive force Hcj, a magnetic induction coercive force Hcb, a magnetic energy product (BH)max, and a critical magnetic field strength and the like can be detected comprehensively; and a product with a poor room temperature performance and a product with a poor high temperature performance can be detected. High-temperature demagnetization can be carried out on multiple or even hundreds of samples simultaneously; the measurement of the open-circuit flux can be carried out conveniently; and the method has the characteristics of accuracy, simpleness, rapidity, and low cost and is suitable for application to large-scale production.

The invention discloses a method for preparing an Nb3Al superconducting wire precursor. The method comprises the steps of preparing a single-core composite rod by means of a Nb rod, a Ta-containing foil and a Cu pipe; rolling a prepared single-core composite rod for forming a hexagonal rod with a regular hexagonal cross section; loading a plurality of prepared hexagonal rods into a Cu packaging pipe and sealing, thereby forming a composite blank ingot; preparing a Cu-packaged composite rod from the prepared composite blank ingot through a heat extrusion processing procedure; and preparing an Nb3Al superconducting wire precursor lead through a plurality of drawing processing procedures. The Nb3Al superconducting wire precursor prepared according to the method of the invention has functions of effectively suppressing coupling between superconducting performance core filaments and remarkably reducing AC loss of a final superconducting wire under a precondition that superconducting performances such as superconducting transition temperature, critical current density and upper critical magnetic field are not ensured.

The invention discloses a preparation method of a carbon nano-tube composite material with enhancing characteristics. The composite materials of carbon nano-tubes (CNTs) and a metal carbide include spiral carbon nano-tubes/metal carbide composite fiber and film. According to the composite fiber, carbon nano-tubes are drawn or twisted from a carbon nano-tube array, such that spinning fiber is formed; the spinning fiber is immersed into a metal precursor solution; and the mixture is heated in a reductive gas comprising carbon-source gas, such that the composite material is prepared. Compared with direct-spinning fiber, the carbon nano-tube composite material with enhancing characteristics has the advantages that: the composite has higher tensile strength, conductivity, and tensile modulus; 2, a parallel tape composite structure comprising carbon nano-tube array embedded in an NbC film shows enhanced conductivity and improved superconductivity along a CNT axial direction; 3, enhanced upper critical magnetic field of a NbC/CNT composite film shows that the NbC coherence length is reduced with the CNTs content in the NbC array; and 4, a nano-mechanical test also proofs the potential application of the material in enhancing the fracture toughness of the NbC/CNT composite film.

The invention discloses a preparation method for a high-flexibility samarium-cobalt permanent magnet. The preparation method comprises the steps of preparing raw materials, carrying out vacuum melting, carrying out hydrogen demolishing, adding a small amount of silver, a dispersing agent and an antioxidant to a jet mill to be grinded, carrying out orientation and blank pressing, and sintering the blank to obtain the product. The samarium-cobalt permanent magnet prepared by the preparation method has obviously fine crystalline grains, so that it is ensured that the sintered crystalline grains are equal in size and uniform; and therefore, the fracture toughness property of the sintered permanent magnet is improved, particularly, the residual magnetism Br, the maximum magnetic energy product (BH)max and critical magnetic field Hk are improved.

The invention belongs to the technical field of superconducting electrical engineering, and in particular relates to a Rutherford cable based on ReBCO isotropic superconducting strands. When a high field magnet coil is manufactured with a high current low temperature superconducting cable, the problems of low operation current density, low critical magnetic field intensity, small operation temperature range, poor stretch mechanical property and the like are solved. The invention proposes the Rutherford cable based on ReBCO isotropic superconducting strands. The cable is composed of a center conductor, the ReBCO isotropic superconducting strands, a metal sheath and a cooling channel. The ReBCO isotropic superconducting strands are closely arranged as sub-strands around the center conductor and are spirally wound. Complete transposition of the ReBCO isotropic superconducting strands is realized. The Rutherford cable has the advantages of great critical current isotropy, high operation temperature, high operation current density, good mechanical property, easy bending, simple and mature production process and the like, and is suitable for large-scale production. The application of the ReBCO isotropic superconducting strands in a nuclear fusion large superconducting magnet coil and other devices is expanded.

A method for producing a high temperature superconductor (=HTS) coated conductor (12), wherein a buffer layer (2; 22) and an HTS layer (4; 24; 65) are deposited on a substrate (1; 21), with the following steps: a) after depositing the buffer layer (2; 22), the surface (2a) is locally roughened, resulting in a roughened surface (13), b) a non-superconducting, closed intermediate layer (3; 23) is deposited on top of the roughened surface (13), c) and the HTS layer (4; 24; 65) is deposited on top of the intermediate layer (3; 23). A simple method for producing a HTS coated conductor with reduced losses, and with improved critical current and critical magnetic field is thereby provided.

The invention relates to a rare earth doped niobium material for a radio frequency superconducting cavity, belonging to the technical field of superconducting accelerators. The rare earth doped niobium material is a high-purity niobium material doped with a scandium or yttrium element, and the atomic ratio content range of the doped scandium or yttrium is 0.01%-0.5%. The preparation method comprises a smelting doping way or an ion injection way. In the rare earth doped niobium material prepared by the smelting doping way, impurity atoms can be uniformly distributed in the niobium material; and in the rare earth doped niobium material prepared by the ion injection way, the impurity atoms can be only distributed in a 500nm range of the surface layer of the niobium material. The niobium material disclosed by the invention can reduce the electron mean free path of the material and improve. According to the invention, the electron mean free path of the niobium material disclosed by the invention can be reduced and a lower critical magnetic field and an upper critical magnetic field can be improved. The radio frequency superconducting cavity prepared by the material has a higher quenching magnetic field and can work under a higher magnetic field and provide a higher acceleration electric field. A smelting doping method disclosed by the invention is relatively simple, and the preparation speed is high. By adopting an ion injection method, the doping content is easy to control, and the using quantity of the scandium or the yttrium is also saved.

An alarm method for preventing power theft through a strong magnetic field comprises the following steps: a. detecting the magnetic field strength around an electric energy meter; b, judging whether the magnetic field strength around the electric energy meter exceeds critical magnetic field strength, and determining that an abnormal magnetic field occurs if the magnetic field strength around the electric energy meter exceeds the critical magnetic field strength; c, monitoring whether the duration of the abnormal magnetic field reaches critical time, and determining that there is hidden danger of power theft if the duration of the abnormal magnetic field reaches the critical time; d, sending an alarm signal to a worker, and recording the number of sending times of the alarm signal; and e, monitoring whether a response signal is received within set time after the alarm signal is sent and judging whether the number of sending times of the alarm signal reaches a set number of times, returning to step d under the condition that the number of sending times of the alarm signal does not reach the set number of times if no response signal is received, sending an alarm signal to a backend server if the number of sending times of the alarm signal reaches the set number of times, and then ending the process and automatically going to next round of alarm standby state. The method of the invention can be implemented in a fully automatic way, and is high in accuracy. By adopting the method, the hidden danger of power theft can be found the first time.

The invention provides a graphene / doped two-dimensional layered material Van der Waals heterojunction superconducting composite structure, a superconducting device and a manufacturing method thereofand relates to the superconducting material technology field. A graphene layer and a layered structure of 2n + 1 layers formed by alternative doped two-dimensional layered materials are included. Anouter layer of the layered structure is the graphene layer, and the n is an integer of 1 to 50. A region where graphene and the doped two-dimensional layered material are completely overlapped vertically forms a superconducting region. The graphene layer and the doped two-dimensional layered material are self-assembled into one body by a Van der Waals force. A defect that an existing Van der Waalsheterojunction superconducting material can only work at an extremely low temperature is solved. The graphene / doped two-dimensional layered material heterojunction superconducting material has a simple structure, excellent performance, a high critical temperature and a high critical magnetic field, low material cost, and good mechanical and machining performance.

The invention relates to an iron-based superconducting material and a method for preparing the same. The composition of the material is expressed by the following formula: (Ca1-xREx)FeAsF, wherein x is more than 0.2 and less than 0.6; and RE maybe La, Ce, Pr, Nd or Sm. The method for preparing the material comprises the following steps of: preparing samples of precursors of CaAs and REAs; and using rare earth metallic ions to partially replace Ca ions at a high temperature by the solid-state chemical reaction method and the ion doping mechanism so as to obtain the iron-based superconducting material with a calcium-fluorine structure. The superconducting transition temperature of the superconducting material is 30 to 56K, and the preparation method is simple; and the upper critical magnetic field of the superconducting material at a low temperature is estimated to be 120 teslas, so that the superconducting material is applicable in fields of superconducting power transmission, generation of strong magnetic fields and the like.

A high temperature superconductor (=HTS) coated conductor (1), comprising an HTS layer (11) deposited epitaxially on a substrate (2), wherein the HTS layer (11) exhibits a lattice with a specific crystal axis being oriented perpendicular to the substrate plane (SP), in particular wherein the HTS layer material is of ReBCO type and the c-axis (c) is oriented perpendicular to the substrate plane (SP), wherein the HIS layer (11) comprises particle inclusions (4),in particular wherein the particle inclusions (4) may be used to introduce pinning of magnetic flux, is characterized in that at least a part (4a) of the particle inclusions (4) are formed of the same material as the HTS layer (11), and/or of chemical fractions of the material of the HTS layer (11), such that the average stoichiometry of said part (4a) of the particle inclusions (4) corresponds to the stoichiometry of the HTS layer (11), and that the particle inclusions of said part (4a) are discontinuities of the lattice of the HTS layer (11). A more simple method for producing a HTS coated conductor with reduced losses, and with improved critical current and critical magnetic field is thereby provided.

The invention discloses a quantum well terahertz detector which is composed of a multiple quantum well chip and a superconducting magnet system. Interaction between a donor level in a barrier layer in the multiple quantum well chip and a sub-band energy level in a potential well layer is regulated effectively by exerting an applied magnetic field so that electrons are transferred from a ground state sub-band energy level in the potential well layer to the donor level in the barrier layer, and incidence THz radiation is detected by utilizing electron transition between the donor levels in the barrier layer. According to the quantum well terahertz detector, after the applied magnetic field increases to a critical magnetic field Bc, due to the fact that THz detecting can be conducted by utilizing electron transition between the donor levels, the quantum well terahertz detector is free from grating coupling or angle lapping coupling of 45 degrees, the THz radiation is absorbed and responded under the condition of normal incidence, the defects caused by principle of an existing quantum well structure detector are overcome, and responsivity can be improved substantially.

The invention relates to the technical field of optical measurement, and discloses refractive index measurement equipment and a refractive index measurement method and device. The refractive index measurement range of the refractive index measurement equipment is adjustable, and thus the measurement application range is widened. The refractive index measurement equipment comprises a magnetic field generation device generating an adjustable magnetic field, a shell, a light transmitter, a light receiver, a sample to be measured and a control processor, wherein the shell is located in the magnetic field generated by the magnetic field generation device and is filled with magnetofluid, the light transmitter, the light receiver and the sample to be measured are immersed in the magnetofluid, and the control processor is connected with the magnetic generation device and the light receiver. The light transmitter is used for transmitting light towards the sample to be measured, the light receiver is used for receiving light reflected by the sample to be measured, and the included angle of the reflected light and the incident light is a set included angle; the control processor is used for judging whether total reflection can happen, determining the refractive index of the magnetofluid according to the critical magnetic field intensity in total reflection and determining the refractive index of the sample to be measured according to the refractive index of the magnetofluid and the set included angle.