The super-high speed high temperature superconductor (HTS) maglev evacuated tube transport (ETT) is a promising transport mode for the future. As a key component of the HTS maglev vehicle, the permanent magnet gui...The super-high speed high temperature superconductor (HTS) maglev evacuated tube transport (ETT) is a promising transport mode for the future. As a key component of the HTS maglev vehicle, the permanent magnet guide- ways (PMGs) with different geometrical configurations and iron yoke widths are analyzed by finite element method (FEM). The levitation force of a single onboard HTS maglev device over the designed PMG at different field cooling heights (FCH) is measured by magnetic levitation measurement system. Based on the designed PMG and experimental results, a preliminary scheme of subterranean super-high speed HTS maglev ETT is described in this paper. The HTS maglev ETT is mainly composed of an evacuated tube, HTS maglev vehicle, PMG, propulsion system, station, emergency rescue system, etc. In addition, a subterranean tube that consists of foundation tube and vacuum airproof layer is introduced. In order to convert the stress caused by the air pressure difference between inside and outside of the vehicle, a multi-circular vehicle body is designed. The vehicle is driven by a linear motor propulsion system under the control of a ground controlling system. The scheme of long-distance super-high speed passenger transportation is accomplished by the connection of different vehicles.展开更多
A modified spark plasma sintering(SPS) technique was developed for the fabrication of Bi2Sr2CaCu2Ox(Bi-2212)superconducting bulks with better intergrain connections. The influences of the modified SPS process on t...A modified spark plasma sintering(SPS) technique was developed for the fabrication of Bi2Sr2CaCu2Ox(Bi-2212)superconducting bulks with better intergrain connections. The influences of the modified SPS process on the microstructures, intergrain connections, and related superconducting properties were systematically analyzed. The modified SPS process can not only increase the final density of the bulk samples but also enhance the texture structures. Clean grain boundaries were obtained instead of the intergrain amorphous layers. Therefore the intergranular properties were obviously improved. Due to the better intergrain connections and the stronger flux pinning properties, the critical current densities of the Bi-2212 bulks obtained via the modified SPS process were greatly increased. The obtained improvements imply the possibility for the modified SPS technique to be used for enhancing the superconducting properties of the Bi-2212 tapes.展开更多
Superconductor YBa_2Cu_3O_(7-x) used as a material for lithium battery was examined in 1NLiClO_4 propylene carbonate/1,2-dimethoxyethane (1:1) solution. YBa_2Cu_3O_(7-x) exhibited 150 mAh/g of discharge capacity at 25...Superconductor YBa_2Cu_3O_(7-x) used as a material for lithium battery was examined in 1NLiClO_4 propylene carbonate/1,2-dimethoxyethane (1:1) solution. YBa_2Cu_3O_(7-x) exhibited 150 mAh/g of discharge capacity at 250 uA/cm^2 discharge current. An ac impedance measurements was carried out, the results have shown that the electrode reaction has low charge-transfer resistance and the chemical diffusion coeffic ient of Li^+ has a value of 10^(-11) cm^2/sec.展开更多
The addition Of Pb enhances the hightemperature stability as well as theproportion of the high Tphase in Bi-Sr-Ca-Cu-O superconductor.The sample A with nominal composi-tion of BiSrCaCuOwas synthesized bySolid state re...The addition Of Pb enhances the hightemperature stability as well as theproportion of the high Tphase in Bi-Sr-Ca-Cu-O superconductor.The sample A with nominal composi-tion of BiSrCaCuOwas synthesized bySolid state reaction.It was sintered in airat 1153K for 24h,followed by annealingat 773K for 24h and furnace-cooling.The sample B with a nominal compositionof BiPbSrCaCuOwas prepared bymixing PbO with the powder ofBiSrCaCuOwhich had been prefired at1113K for 24h,pressing,sintering at展开更多
After discovering high temperature superconducting materials 20 years ago, the preparation of applicable HTS materials has been pursued along with HTS mechanism and characteristic study. At present, the focus on the a...After discovering high temperature superconducting materials 20 years ago, the preparation of applicable HTS materials has been pursued along with HTS mechanism and characteristic study. At present, the focus on the applied HTS technology has been moving to the industrial preparations from the laboratory research stage, and the technology has been well verified for practical applications from small to large scales. The fabrication techniques of engineering HTS materials are being industrialized; and various HTS devices are also on the way towards practical applications. This paper provides a comprehensive summary on the applied high temperature superconductivity with regard to various applicable HTS materials, their preparation techniques and charac- terization, and applications in a wide range.展开更多
Silver-clad (Bi,Pb)2Sr2Ca2Cu3O10+x long wires produced by powder-in-tube techniques, which have been recognized as the first generation of the High Temperature Superconducting (HTS) wires, are expected to apply w...Silver-clad (Bi,Pb)2Sr2Ca2Cu3O10+x long wires produced by powder-in-tube techniques, which have been recognized as the first generation of the High Temperature Superconducting (HTS) wires, are expected to apply widely especially in strong current applications. In this work, the processing, characterization and application of the silver-clad (Bi,Pb)2Sr2Ca2Cu3Ol0+x HTS wires are summarized. The HTS wires are fabricated using the combination of powder-in-tube technique, and the resulting wires are fully characterized by the means of chemical analyses, microstructural observation, electrical and magnetic measurements. The relationship among fabrication parameters, chemical and microstructural characteristics, and electrical and magnetic properties are analyzed. Applications of the HTS wires have also been introduced according to their strong current behaviors with various prototype devices made.展开更多
Twenty years after the discovery of hightemperature superconductors (HTSs), the HTS materials now have been well developed. Meanwhile the mechanism of superconductivity is still one of the topical interests in physi...Twenty years after the discovery of hightemperature superconductors (HTSs), the HTS materials now have been well developed. Meanwhile the mechanism of superconductivity is still one of the topical interests in physics. The achievements made on HTS materials and theories during the last twenty years are reviewed comprehensively in this paper.展开更多
The cube textured pure Ni and non magnetic Cu Ni tapes were obtained by rolling and recrystallization, and these tapes are suitable as substrates of the second generation high temperature superconducting tape. The t...The cube textured pure Ni and non magnetic Cu Ni tapes were obtained by rolling and recrystallization, and these tapes are suitable as substrates of the second generation high temperature superconducting tape. The texture of tapes was studied using Orientation Distribution Function (ODF) and φ scans. The results indicate that sharp cube texture of Cu 0 70 Ni 0.30 and pure Ni was formed at 1000 ℃ and that of Cu 0 85 Ni 0.15 was formed at 900 ℃. The intensities of cube texture differ from each other. Uniform equiaxial crystallites are formed in all the tapes and the size of Cu 0.85 Ni 0.15 is larger than that of Cu 0.70 Ni 0.30 and pure Ni. Annealing twin is formed in Cu 0.85 Ni 0.15 and Cu 0.70 Ni 0.30 .展开更多
Powder in tube process(PIT) was adopted for the fabrication of single filament Bi-2223 tapes, and a heat treatment process including the first heat treatment(HT1), intermediate rolling(IR), and second heat treat...Powder in tube process(PIT) was adopted for the fabrication of single filament Bi-2223 tapes, and a heat treatment process including the first heat treatment(HT1), intermediate rolling(IR), and second heat treatment(HT2) was performed. The phase evolution mechanism and microstructure changes during these heat treatment processes were systematically discussed. The influences of HT1 parameters on the phase evolution process of Bi-2223 tapes were discussed. With the optimized HT1 process, a proper Bi-2223 content of about 90% was achieved. HT2 process was also optimized by adding a post annealing process. An obvious increase of current capacity was obtained due to the enhancement of intergrain connections. Single filament Bi-2223 tapes with the critical current of Ic-90 A were fabricated with the optimized sintering process.展开更多
The high‐temperature superconducting(HTS)dynamo enables injection of large DC currents into a superconducting coil,without the need for thermally‐inefficient current leads.Because of this important advantage,there i...The high‐temperature superconducting(HTS)dynamo enables injection of large DC currents into a superconducting coil,without the need for thermally‐inefficient current leads.Because of this important advantage,there is significant interest in using such technology to energise superconducting coils in superconducting rotating machines and NMR/MRI magnets.Despite the extensive experimental work carried out over the past decade,there was–until very recently–considerable confusion and debate regarding the physical origin of the HTS dynamo’s DC output voltage.Numerical modelling has played a key role in elucidating the underlying physics of such devices and several different numerical models have now been developed as useful and cost‐effective tools to not only explain and further examine experimental results,but also optimise and improve dynamo designs.This review summarises all of the developments in this important area over recent years,including modelling the open‐circuit voltage behaviour in 2D and 3D,the definition of a new benchmark problem for the HTS modelling community,investigating key dynamo parameters,modelling dynamic coil charging behaviour and calculating losses.A view towards the future is provided,including the outstanding challenges and the developments required to address these.展开更多
With the rapid development of high temperature superconducting(HTS)technology,second generation(2G)HTS materials have become a promising alternative to traditional conductive materials in the power transmission indust...With the rapid development of high temperature superconducting(HTS)technology,second generation(2G)HTS materials have become a promising alternative to traditional conductive materials in the power transmission industry.Recently,the topic of using HTS materials in wireless power transfer(WPT)systems for electric vehicles(EVs)has attracted widespread attention in the background of net zero transport.With virtually zero DC resistance and superior current‐carrying capacity,HTS materials can achieve high quality factor and power density in the WPT resonant circuits compared to conventional metals,e.g.,copper.However,the optimal working frequency for the conventional WPT system is relatively high in the order of kilohertz level.Superconducting coils working at high frequencies could generate high AC losses,reducing the overall power transfer efficiency(PTE)and increasing the cooling burden.In order to improve the PTE of HTS‐WPT systems,the AC loss mitigation methods for different HTS coil topologies have been investigated in this paper by varying the inter‐turn gap and tape width.Three HTS coil structures,namely the spiral coil,the solenoid coil and the double pancake(DP)coil,have been studied with a 2D axisymmetric multi‐layer numerical model based on the H‐formulation,and the simulation results have been validated by the published experimental data.The general loss characteristics,loss distributions in each turn,as well as magnetic flux densities have been analysed in detail for three types of HTS coils.Moreover,the impact of these two loss reduction methods on the WPT performance has also been evaluated.Findings have shown that increasing the inter‐turn gap and tape width can effectively reduce the AC power losses and increase the PTE of the HTS‐WPT system.The spiral coil demonstrates the highest AC power loss reduction effect and PTE while maintaining a stable level of magnetic fields.This paper is believed to deepen the understanding of superconducting WPT and provide a useful reference for more efficient wireless energisation applications.展开更多
This paper presents a fully coupled model to account for the flux pinning induced giant magnetostriction in type-Ⅱ superconductors under alternating magnetic field The superconductor E-J constitutive law is character...This paper presents a fully coupled model to account for the flux pinning induced giant magnetostriction in type-Ⅱ superconductors under alternating magnetic field The superconductor E-J constitutive law is characterized by power law where the critical current density is assumed to depend exponentially on the flux density. The governing equations of the two-field problem (i.e., the interactions of elastic and magnetic effects) are formulated in a two-dimensional model. The magnetostriction curves and magnetization loops are calculated over a wide range of parameters. The effects of applied magnetic field frequency f and amplitude B0 and critical current density on magnetostriction and magnetization are discussed. Results show that the critical current density of high temperature superconductor (HTS) YBCO has a significant effect on the magnetization and magnetostriction. The pinning-induced magnetostriction which has been observed in experiment can be qualitatively simulated by this model.展开更多
Tl-based superconducting devices have been drawn much attention for their high transition temperature(T_c), which allow the high temperature superconductors(HTS) devices to operate at temperature near 100 K. The reali...Tl-based superconducting devices have been drawn much attention for their high transition temperature(T_c), which allow the high temperature superconductors(HTS) devices to operate at temperature near 100 K. The realization of Tlbased devices will promote the research and application of HTS devices. In this work, we present transport properties of Tl_(2) Ba_(2) CaCu_(2) O_(8)(Tl-2212) microbridges across a low-angle step on LaAlO_(3)(LAO) substrate. We experimentally demonstrate intrinsic Josephson effects(IJEs) in Tl-2212 films by tailoring the geometry, i.e., reducing the width of the microbridges. In the case of a 1 μm width microbridge, in addition to the observation of voltage branches and remarkable hysteresis on the current–voltage(I–V) characteristics, the temperature dependence of differential resistance shows a finite resistance above 60 K when the bias current is below the critical current. For comparison, the wider microbridges are also investigated, exhibiting a highly critical current but do not showing obvious IJEs.展开更多
YBCO textured thick film was prepared by direct peritectic growth method. Microstructure of the film was characterized. Electron backscattered diffraction (EBSD) technique was applied to the film for quantitative te...YBCO textured thick film was prepared by direct peritectic growth method. Microstructure of the film was characterized. Electron backscattered diffraction (EBSD) technique was applied to the film for quantitative texture analysis. The main difficulty in resolving the orientation of YBCO pseudo-cubic structure was investigated. Automated orientation mapping was performed on YBCO thick film. Local texture was presented in the form of orientation maps. Misorientation distribution and crystal growth characterization in the YBCO thick film were revealed. Large domains with well-aligned YBCO grains were formed. Each domain presented clear in-plane and out-plane textures.展开更多
In December 2021,the 35-kV kilometer-level high-temperature superconducting(HTS)demonstration cable was officially connected to the grid in Xuhui District,Shanghai,China.A three-in-one HTS cable with a rated current o...In December 2021,the 35-kV kilometer-level high-temperature superconducting(HTS)demonstration cable was officially connected to the grid in Xuhui District,Shanghai,China.A three-in-one HTS cable with a rated current of 2.2 kA,which replaces four-parallel lines XLPE cables,has been used in this project.This cable powers one of the busiest districts of Shanghai and serves to demonstrate and study the stability and reliability of a superconducting cable in the municipal power system.This project officially started in February 2019,and the type test of the prototype cable system was completed in November 2019.The commissioning test will be completed in November 2021.This paper introduces the main operating parameters,relevant research studies,and tests of this project.展开更多
This paper introduces the relevant parameters and related characteristics of the LabVIEW and PCI6221 data acquisition (DAQ) card, describes in detail the approach of building the measure and control platform of virt...This paper introduces the relevant parameters and related characteristics of the LabVIEW and PCI6221 data acquisition (DAQ) card, describes in detail the approach of building the measure and control platform of virtual instrument (VI) using LabVIEW and PCI6221, specifically discusses the system's application in high temperature superconductor (HTS) research including the test of HTS volt-ampere characteristics and the HTS magnetic energy storage. The experiments prove that the VI test and control system is easy to build and convenient to use.展开更多
Pure Ni and Ni alloy tapes with sharp cube texture and low-angle grain boundaries prepared by thermomechanical process were extensively used as substrates for coated conductor. The thermomechanical process usually inc...Pure Ni and Ni alloy tapes with sharp cube texture and low-angle grain boundaries prepared by thermomechanical process were extensively used as substrates for coated conductor. The thermomechanical process usually includes hot forging and cold rolling. In this study, a hot-rolling process between hot forging and cold rolling was induced. The influence of hot rolling on the cube texture of pure Ni was discussed. Sharp cube texture on pure Ni was obtained by suitable hot rolling, cold rolling, and recrystallization treatment. This deformation texture of tape was studied using orientation distribution function (ODF). Orientation mapping, content of the cube texture, and grain boundary distribution were performed using an EBSD system mounted on LEO-1450 SEM. The results show that the substrates that are hot rolled have a sharp cube texture and low-angle grain boundaries.展开更多
The critical current density behaviors across a bicrystal grain boundary(GB) inclined to the current direction with different angles in YBa2Cu3O7-δ bicrystal junctions in magnetic fields are investigated.There are...The critical current density behaviors across a bicrystal grain boundary(GB) inclined to the current direction with different angles in YBa2Cu3O7-δ bicrystal junctions in magnetic fields are investigated.There are two main reasons for the difference in critical current density in junctions at different GB inclined angles in the same magnetic field:(i) the GB plane area determines the current carrying cross section;(ii) the vortex motion dynamics at the GB affects the critical current value when the vortex starts to move along the GB by Lorentz force.Furthermore,the vortex motion in a bicrystal GB is studied by investigating transverse(Hall) and longitudinal current–voltage characteristics(I–Vxx and I–Vxy).It is found that the I–Vxx curve diverges from linearity at a high driving current,while the I–Vxy curve keeps nearly linear,which indicates the vortices inside the GB break out of the GB by Lorentz force.展开更多
A high temperature superconductor (HTS) cable system of both a length of 4 metre and a normal current of 2 KA with terminations and a cooling system has been built up and tested. The cable conductor was made of Bi-2...A high temperature superconductor (HTS) cable system of both a length of 4 metre and a normal current of 2 KA with terminations and a cooling system has been built up and tested. The cable conductor was made of Bi-2223 tape. A space maintained vacuum between two corrugated stainless steel tubes functions as the cryostat surrounding the superconductor. A series of tests were carried out to verify the functions of the system. The important data obtained can be used to make longer HTS cable systems.展开更多
CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic ...CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic devices and systems for practical applications such as mineral and exploration as well as some niche applications in emerging science and technology areas. This article presents an overview of the CSIRO research activities in HTS supercon- ducting electronics since 1987, outlining the HTS junction and device technology as well as various application systems developed by the group.展开更多
基金support from the PCSIRT of the Ministry of Education of China(IRT0751)the National Natural Science Foundation of China (Grant Nos. 50588201, and 50872116)+3 种基金the National High Technology Research and Development Program of China (863 program: 2007AA03Z203)the Research Fund for the Doctoral Program of Higher Education of China (SRFDP200806130023)the Fundamental Research Funds for the Central Universities(SWJTU09BR152 and SWJTU09ZT24)the Doctoral Innovation Foundation of Southwest Jiaotong University (X1899124710003)
文摘The super-high speed high temperature superconductor (HTS) maglev evacuated tube transport (ETT) is a promising transport mode for the future. As a key component of the HTS maglev vehicle, the permanent magnet guide- ways (PMGs) with different geometrical configurations and iron yoke widths are analyzed by finite element method (FEM). The levitation force of a single onboard HTS maglev device over the designed PMG at different field cooling heights (FCH) is measured by magnetic levitation measurement system. Based on the designed PMG and experimental results, a preliminary scheme of subterranean super-high speed HTS maglev ETT is described in this paper. The HTS maglev ETT is mainly composed of an evacuated tube, HTS maglev vehicle, PMG, propulsion system, station, emergency rescue system, etc. In addition, a subterranean tube that consists of foundation tube and vacuum airproof layer is introduced. In order to convert the stress caused by the air pressure difference between inside and outside of the vehicle, a multi-circular vehicle body is designed. The vehicle is driven by a linear motor propulsion system under the control of a ground controlling system. The scheme of long-distance super-high speed passenger transportation is accomplished by the connection of different vehicles.
基金Project supported by the National Basic Research Program of China(Grant No.2011CBA00104)the National Natural Science Foundation of China(Grant No.51472206)+1 种基金the ITER Project of China(Grant No.2013GB110001)the Program for Innovative Research Team in Shaanxi Province,China(Grant No.2013KCT-07)
文摘A modified spark plasma sintering(SPS) technique was developed for the fabrication of Bi2Sr2CaCu2Ox(Bi-2212)superconducting bulks with better intergrain connections. The influences of the modified SPS process on the microstructures, intergrain connections, and related superconducting properties were systematically analyzed. The modified SPS process can not only increase the final density of the bulk samples but also enhance the texture structures. Clean grain boundaries were obtained instead of the intergrain amorphous layers. Therefore the intergranular properties were obviously improved. Due to the better intergrain connections and the stronger flux pinning properties, the critical current densities of the Bi-2212 bulks obtained via the modified SPS process were greatly increased. The obtained improvements imply the possibility for the modified SPS technique to be used for enhancing the superconducting properties of the Bi-2212 tapes.
基金Supported by the National Natural Science Foundation of China
文摘Superconductor YBa_2Cu_3O_(7-x) used as a material for lithium battery was examined in 1NLiClO_4 propylene carbonate/1,2-dimethoxyethane (1:1) solution. YBa_2Cu_3O_(7-x) exhibited 150 mAh/g of discharge capacity at 250 uA/cm^2 discharge current. An ac impedance measurements was carried out, the results have shown that the electrode reaction has low charge-transfer resistance and the chemical diffusion coeffic ient of Li^+ has a value of 10^(-11) cm^2/sec.
文摘The addition Of Pb enhances the hightemperature stability as well as theproportion of the high Tphase in Bi-Sr-Ca-Cu-O superconductor.The sample A with nominal composi-tion of BiSrCaCuOwas synthesized bySolid state reaction.It was sintered in airat 1153K for 24h,followed by annealingat 773K for 24h and furnace-cooling.The sample B with a nominal compositionof BiPbSrCaCuOwas prepared bymixing PbO with the powder ofBiSrCaCuOwhich had been prefired at1113K for 24h,pressing,sintering at
文摘After discovering high temperature superconducting materials 20 years ago, the preparation of applicable HTS materials has been pursued along with HTS mechanism and characteristic study. At present, the focus on the applied HTS technology has been moving to the industrial preparations from the laboratory research stage, and the technology has been well verified for practical applications from small to large scales. The fabrication techniques of engineering HTS materials are being industrialized; and various HTS devices are also on the way towards practical applications. This paper provides a comprehensive summary on the applied high temperature superconductivity with regard to various applicable HTS materials, their preparation techniques and charac- terization, and applications in a wide range.
文摘Silver-clad (Bi,Pb)2Sr2Ca2Cu3O10+x long wires produced by powder-in-tube techniques, which have been recognized as the first generation of the High Temperature Superconducting (HTS) wires, are expected to apply widely especially in strong current applications. In this work, the processing, characterization and application of the silver-clad (Bi,Pb)2Sr2Ca2Cu3Ol0+x HTS wires are summarized. The HTS wires are fabricated using the combination of powder-in-tube technique, and the resulting wires are fully characterized by the means of chemical analyses, microstructural observation, electrical and magnetic measurements. The relationship among fabrication parameters, chemical and microstructural characteristics, and electrical and magnetic properties are analyzed. Applications of the HTS wires have also been introduced according to their strong current behaviors with various prototype devices made.
文摘Twenty years after the discovery of hightemperature superconductors (HTSs), the HTS materials now have been well developed. Meanwhile the mechanism of superconductivity is still one of the topical interests in physics. The achievements made on HTS materials and theories during the last twenty years are reviewed comprehensively in this paper.
文摘The cube textured pure Ni and non magnetic Cu Ni tapes were obtained by rolling and recrystallization, and these tapes are suitable as substrates of the second generation high temperature superconducting tape. The texture of tapes was studied using Orientation Distribution Function (ODF) and φ scans. The results indicate that sharp cube texture of Cu 0 70 Ni 0.30 and pure Ni was formed at 1000 ℃ and that of Cu 0 85 Ni 0.15 was formed at 900 ℃. The intensities of cube texture differ from each other. Uniform equiaxial crystallites are formed in all the tapes and the size of Cu 0.85 Ni 0.15 is larger than that of Cu 0.70 Ni 0.30 and pure Ni. Annealing twin is formed in Cu 0.85 Ni 0.15 and Cu 0.70 Ni 0.30 .
基金Funded by the National Natural Science Foundation of China(No.51472206)the National ITER Program of China(2015GB115001)the Program for Innovative Research Team in Shaanxi Province(No.2013KCT-07)
文摘Powder in tube process(PIT) was adopted for the fabrication of single filament Bi-2223 tapes, and a heat treatment process including the first heat treatment(HT1), intermediate rolling(IR), and second heat treatment(HT2) was performed. The phase evolution mechanism and microstructure changes during these heat treatment processes were systematically discussed. The influences of HT1 parameters on the phase evolution process of Bi-2223 tapes were discussed. With the optimized HT1 process, a proper Bi-2223 content of about 90% was achieved. HT2 process was also optimized by adding a post annealing process. An obvious increase of current capacity was obtained due to the enhancement of intergrain connections. Single filament Bi-2223 tapes with the critical current of Ic-90 A were fabricated with the optimized sintering process.
文摘The high‐temperature superconducting(HTS)dynamo enables injection of large DC currents into a superconducting coil,without the need for thermally‐inefficient current leads.Because of this important advantage,there is significant interest in using such technology to energise superconducting coils in superconducting rotating machines and NMR/MRI magnets.Despite the extensive experimental work carried out over the past decade,there was–until very recently–considerable confusion and debate regarding the physical origin of the HTS dynamo’s DC output voltage.Numerical modelling has played a key role in elucidating the underlying physics of such devices and several different numerical models have now been developed as useful and cost‐effective tools to not only explain and further examine experimental results,but also optimise and improve dynamo designs.This review summarises all of the developments in this important area over recent years,including modelling the open‐circuit voltage behaviour in 2D and 3D,the definition of a new benchmark problem for the HTS modelling community,investigating key dynamo parameters,modelling dynamic coil charging behaviour and calculating losses.A view towards the future is provided,including the outstanding challenges and the developments required to address these.
文摘With the rapid development of high temperature superconducting(HTS)technology,second generation(2G)HTS materials have become a promising alternative to traditional conductive materials in the power transmission industry.Recently,the topic of using HTS materials in wireless power transfer(WPT)systems for electric vehicles(EVs)has attracted widespread attention in the background of net zero transport.With virtually zero DC resistance and superior current‐carrying capacity,HTS materials can achieve high quality factor and power density in the WPT resonant circuits compared to conventional metals,e.g.,copper.However,the optimal working frequency for the conventional WPT system is relatively high in the order of kilohertz level.Superconducting coils working at high frequencies could generate high AC losses,reducing the overall power transfer efficiency(PTE)and increasing the cooling burden.In order to improve the PTE of HTS‐WPT systems,the AC loss mitigation methods for different HTS coil topologies have been investigated in this paper by varying the inter‐turn gap and tape width.Three HTS coil structures,namely the spiral coil,the solenoid coil and the double pancake(DP)coil,have been studied with a 2D axisymmetric multi‐layer numerical model based on the H‐formulation,and the simulation results have been validated by the published experimental data.The general loss characteristics,loss distributions in each turn,as well as magnetic flux densities have been analysed in detail for three types of HTS coils.Moreover,the impact of these two loss reduction methods on the WPT performance has also been evaluated.Findings have shown that increasing the inter‐turn gap and tape width can effectively reduce the AC power losses and increase the PTE of the HTS‐WPT system.The spiral coil demonstrates the highest AC power loss reduction effect and PTE while maintaining a stable level of magnetic fields.This paper is believed to deepen the understanding of superconducting WPT and provide a useful reference for more efficient wireless energisation applications.
基金supported by the National Natural Science Foundation of China(Nos.11272140,10902046,11032006 and11121202)the Fundamental Research Funds for the Central Universities(lzujbky-2015-176)National Key Project of Magneto-Constrained Fusion Energy Development Program(2013GB110002)
文摘This paper presents a fully coupled model to account for the flux pinning induced giant magnetostriction in type-Ⅱ superconductors under alternating magnetic field The superconductor E-J constitutive law is characterized by power law where the critical current density is assumed to depend exponentially on the flux density. The governing equations of the two-field problem (i.e., the interactions of elastic and magnetic effects) are formulated in a two-dimensional model. The magnetostriction curves and magnetization loops are calculated over a wide range of parameters. The effects of applied magnetic field frequency f and amplitude B0 and critical current density on magnetostriction and magnetization are discussed. Results show that the critical current density of high temperature superconductor (HTS) YBCO has a significant effect on the magnetization and magnetostriction. The pinning-induced magnetostriction which has been observed in experiment can be qualitatively simulated by this model.
文摘Tl-based superconducting devices have been drawn much attention for their high transition temperature(T_c), which allow the high temperature superconductors(HTS) devices to operate at temperature near 100 K. The realization of Tlbased devices will promote the research and application of HTS devices. In this work, we present transport properties of Tl_(2) Ba_(2) CaCu_(2) O_(8)(Tl-2212) microbridges across a low-angle step on LaAlO_(3)(LAO) substrate. We experimentally demonstrate intrinsic Josephson effects(IJEs) in Tl-2212 films by tailoring the geometry, i.e., reducing the width of the microbridges. In the case of a 1 μm width microbridge, in addition to the observation of voltage branches and remarkable hysteresis on the current–voltage(I–V) characteristics, the temperature dependence of differential resistance shows a finite resistance above 60 K when the bias current is below the critical current. For comparison, the wider microbridges are also investigated, exhibiting a highly critical current but do not showing obvious IJEs.
文摘YBCO textured thick film was prepared by direct peritectic growth method. Microstructure of the film was characterized. Electron backscattered diffraction (EBSD) technique was applied to the film for quantitative texture analysis. The main difficulty in resolving the orientation of YBCO pseudo-cubic structure was investigated. Automated orientation mapping was performed on YBCO thick film. Local texture was presented in the form of orientation maps. Misorientation distribution and crystal growth characterization in the YBCO thick film were revealed. Large domains with well-aligned YBCO grains were formed. Each domain presented clear in-plane and out-plane textures.
文摘In December 2021,the 35-kV kilometer-level high-temperature superconducting(HTS)demonstration cable was officially connected to the grid in Xuhui District,Shanghai,China.A three-in-one HTS cable with a rated current of 2.2 kA,which replaces four-parallel lines XLPE cables,has been used in this project.This cable powers one of the busiest districts of Shanghai and serves to demonstrate and study the stability and reliability of a superconducting cable in the municipal power system.This project officially started in February 2019,and the type test of the prototype cable system was completed in November 2019.The commissioning test will be completed in November 2021.This paper introduces the main operating parameters,relevant research studies,and tests of this project.
文摘This paper introduces the relevant parameters and related characteristics of the LabVIEW and PCI6221 data acquisition (DAQ) card, describes in detail the approach of building the measure and control platform of virtual instrument (VI) using LabVIEW and PCI6221, specifically discusses the system's application in high temperature superconductor (HTS) research including the test of HTS volt-ampere characteristics and the HTS magnetic energy storage. The experiments prove that the VI test and control system is easy to build and convenient to use.
基金Project supported bythe National Basic Research Program China (2006CB601005)
文摘Pure Ni and Ni alloy tapes with sharp cube texture and low-angle grain boundaries prepared by thermomechanical process were extensively used as substrates for coated conductor. The thermomechanical process usually includes hot forging and cold rolling. In this study, a hot-rolling process between hot forging and cold rolling was induced. The influence of hot rolling on the cube texture of pure Ni was discussed. Sharp cube texture on pure Ni was obtained by suitable hot rolling, cold rolling, and recrystallization treatment. This deformation texture of tape was studied using orientation distribution function (ODF). Orientation mapping, content of the cube texture, and grain boundary distribution were performed using an EBSD system mounted on LEO-1450 SEM. The results show that the substrates that are hot rolled have a sharp cube texture and low-angle grain boundaries.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61501222,61371036,and 61571219)the School Scientific Research Fund of Nanjing Institute of Technology,China(Grant Nos.YKJ201418)
文摘The critical current density behaviors across a bicrystal grain boundary(GB) inclined to the current direction with different angles in YBa2Cu3O7-δ bicrystal junctions in magnetic fields are investigated.There are two main reasons for the difference in critical current density in junctions at different GB inclined angles in the same magnetic field:(i) the GB plane area determines the current carrying cross section;(ii) the vortex motion dynamics at the GB affects the critical current value when the vortex starts to move along the GB by Lorentz force.Furthermore,the vortex motion in a bicrystal GB is studied by investigating transverse(Hall) and longitudinal current–voltage characteristics(I–Vxx and I–Vxy).It is found that the I–Vxx curve diverges from linearity at a high driving current,while the I–Vxy curve keeps nearly linear,which indicates the vortices inside the GB break out of the GB by Lorentz force.
文摘A high temperature superconductor (HTS) cable system of both a length of 4 metre and a normal current of 2 KA with terminations and a cooling system has been built up and tested. The cable conductor was made of Bi-2223 tape. A space maintained vacuum between two corrugated stainless steel tubes functions as the cryostat surrounding the superconductor. A series of tests were carried out to verify the functions of the system. The important data obtained can be used to make longer HTS cable systems.
文摘CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic devices and systems for practical applications such as mineral and exploration as well as some niche applications in emerging science and technology areas. This article presents an overview of the CSIRO research activities in HTS supercon- ducting electronics since 1987, outlining the HTS junction and device technology as well as various application systems developed by the group.