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排序方式: 共有772条查询结果,搜索用时 15 毫秒
1.
Multifilament Ag-sheathed BiPbSrCaCuO (2223) superconducting tapes containing 49 filaments were fabricated by the powder-in-tube route and the roll-anneal process. The transport critical current densityJ
c
was 1.3×104 A cm–2 at 77 K and 7×104 A cm–2 at 4.2 K in self-field. A 12-m-long tape was used to construct superconducting solenoids (50, 28, and 14 mm internal diameters) generating dc fields 380–1070 G at 4.2 K. Measurements of the variation ofJ
c
with field (0–1.6 T) and bend strain (0–5%) are used to explain the performance of the solenoids. The critical bend strain of tapes was about 1.5%. 相似文献
2.
The magnetization of a melt-texture growth (MTG) HTSC ring has been studied. It is shown that the magnetic field inside the ring is larger than the external field under a certain range of external magnetic fields. We have also investigated the magnetic field dependence of the response of a detective coil near a rotating superconducting ring. The responses of the MTG sample are different for different cooling methods. 相似文献
3.
Iwao Shimizu Yuji Naito Iwao Yamaguchi Katsuyuki Kaiho Hitoshi Mizoguchi Satoru Yanabu 《Electrical Engineering in Japan》2008,164(1):52-61
Using conventional high‐temperature superconducting wire, a model superconducting fault current limiter (SFCL) is made and tested. Solenoid coil using Bi2223 silver sheath wire is so made that inductance is as small as possible and a vacuum interrupter is connected in series to it. A conventional reactor coil is connected in parallel. When the fault current flows in this equipment, superconducting wire is quenched and current is transferred into the parallel coil because of voltage drop of superconducting wire. This large current in parallel coil actuates magnetic repulsion mechanism of vacuum interrupter. Due to opening of vacuum interrupter, the current in superconducting wire is broken. By using this equipment, current flow time in superconducting wire can be easily minimized. On the other hand, the fault current is also easily limited by large reactance of parallel coil. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 52–61, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20315 相似文献
4.
《功能材料信息》2007,(5)
A dream or interesting problem is to obtain more information based on one measurement,for example to obtain all the thermodynamic functions based on specific heat only. We call it“holographic“study.After more than 10 year‘s efforts,we suggest one possibility(or only one)is to solve an inverse problem(specific heat-phonon spectrum inversion,SPI).In this talk we will review recent development of studies of a class of inverse problems,including Dai‘s exact solution and Chen‘s formula and their unification.T... 相似文献
5.
Ram Bilas 《Bulletin of Materials Science》1993,16(2):109-116
X-ray diffraction, electron paramagnetic resonance, microwave absorption and resistivity measurements were carried out on
YBa2−x
Bi
x
Cu3O7 (0≤x≤0·5) superconductors in order to study the effect of bismuth on the structural and superconducting properties. A decrease
in sintering temperature increased the amount of impurity phase. Transition from an orthorhombic (superconducting) phase to
tetragonal structure produced no significant change in EPR zero-field signal at liquid nitrogen temperature (LNT). The non-resonance
signal height decreased on higher concentration of bismuth. Sintered YBa2−x
Bi
x
Cu3O7 superconductor had a strong EPR zero-field signal at LNT. We have evaluated particle size from XRD and EPR studies. The average
particle size was about 0·4μm. 相似文献
6.
Shunsuke Ohashi 《Electrical Engineering in Japan》2005,150(1):71-77
Magnetic bearing using pinning force of a permanent magnet and a high‐temperature superconductor has been developed. Additional permanent magnet is introduced to increase the levitation force of the magnetic bearing. In this hybrid magnetic bearing system, levitation force is mainly given by the repulsive force of the permanent magnets, and stability for the lateral direction is given by pinning force of the superconductor. The experimental device is developed. A ring‐type superconductor and a bulk one are examined. Levitation characteristics of the hybrid magnetic bearing are measured. The bulk superconductor shows better characteristics of both levitation and lateral stability than the ring one. Levitation force of the hybrid system becomes about twice as large as that of the nonhybrid one. Although, the repulsive force of the permanent magnet decreases the lateral stability of the system, its influence becomes small by choosing an adequate position of the permanent magnets and the superconductor. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 71–77, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10350 相似文献
7.
The dislocation structures of bulk textured and epitaxial thin film YBa2Cu3O7 superconductors are examined. Correlations between increases in flux pinning and dislocation densities are noted. A model
for flux pinning by individual dislocations is presented. This gives a treatment of strain induced effects and effects of
normal state region interactions. It is shown that the values of pinning predicted are in line with experimental observations. 相似文献
8.
The paramagnetic Meissner effect (PME) was observed on the field-cooled M-T curvesof melt-textured Y0.99Nd0.01Ba2Cu3O7-y in applied magnetic fields from 1kOe toJ0kOe. In the magnetic field below 1kOe, the sample undergoes the typical transi-tion from the normal state to the superconducting state when it was cooled down. Theapplied magnetic fields in which the PME occurs, are very high compared with thefields reported in literatures. We propose that the occurrence of the PME may be dueto a phase transition of flux vortices in the superconductors. 相似文献
9.
FAN Yongnian TANG Baozhen QIAO Guiwen Institute of Metal Research Academia Sinica Shenyang China Associate Professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(7):21-24
Interfaces and surfaces of YBa_2Cu_3O_(7-x)(YBCO)-Ag have been studied by SEM-EDXand AES.No effect of Ag on 123 structure in X-ray diffraction pattern was observedfor 0.4 mol Ag doped YBCO.AES analysis indicated that Ag segregated on surfaceof YBCO and resulted in decrease of YBCO-metal lead resistance.In addition,solutionand segregation of Ag as elemental state were often appeared on interfaces and surfacesof high temperature annealed YBCO,whether elemental Ag or compound Ag_2O andAgNO_3 adopted as doping material. 相似文献
10.
利用原位电阻测量、热重分析、电镜观察和电子探针等多种实验手段研究了Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10+δ)(下称BPSCCO)超导材料在不同温度(650—800℃)和不同氧分压(氧气、空气和氮气)下热处理过程中结构变化及其对超导电性的影响,实验结果表明,在稍高氧分压下退火,2223相中的Pb ̄(+2)离子将失稳析出体外,生成类Ca_2PbO_4杂相,导致电阻率和重量增加,其调制结构由纯Pb型(q=βb)逐渐变为纯Bi型(q=βb+c),在低氧分压下退火,类Ca_2PbO_4杂相将分解,整个过程基本可逆.此外还发现,适度析出类Ca_2PbO_4杂相,2223母相的超导转变温度将增高,材料的电传输特性亦将得到改善. 相似文献