共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
3.
ITER电流引线高温超导叠制作工艺及性能测试 总被引:2,自引:0,他引:2
ITER高温超导电流引线载流能力最大要达到68 kA,一根电流引线共需要1000多根银金基Bi-2223高温超导带并联.这些高温超导带分成90叠,每叠由12层带组成.银金基Bi-2223带价格是普通银基Bi系带的4~5倍,而目前欧洲超导公司提供的超导叠的报价几乎是其带价格加倍,所以开发超导叠的制作工艺是非常有价值的.本文详细的介绍了超导叠的真空钎焊制作工艺,并进行了77 K下超导带的接头电阻测试和77 K自场下的临界电流测试,以及模拟在实际运行温度65~5 K条件下高温超导叠的载流能力测试和接头电阻的测试.测试结果证明了此工艺的可行性. 相似文献
4.
Yuan J Rohan ML Shen GX 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2006,182(2):298-307
The use of Bi-2223 high temperature superconducting (HTS) tape as a material for gradient coils in MRI is evaluated in this paper. Bi-2223 tapes have a very high critical current and a very low power loss. A HTS tape gradient coil is expected to provide much higher gradient strength and generate much lower heating than a copper coil. Measurements of the AC power loss of Bi-2223 tapes at typical operating frequencies for gradient coils are presented. The degradation of the critical current and its effect on the increase of AC power loss is analyzed. Practical technical issues such as resistance, gradient strength and mechanical performance are also discussed. A prototype Bi-2223 HTS tape gradient coil is evaluated to verify the concept. 相似文献
5.
6.
M. P. Oomen J. Rieger M. Leghissa B. Fischer Th. Arndt 《Physica C: Superconductivity and its Applications》1998,310(1-4):137-141
In AC power-engineering applications, a large part of the AC loss in the superconductor is due to magnetization by the external field. This magnetic AC loss has been well described for the low-Tc conductors. In Bi-2223 tapes the picture is different due to strong anisotropy, granularity and flux creep. Magnetic AC loss in various twisted and non-twisted Bi-2223 tapes has been measured at power frequencies by a pickup method. The results are compared to theoretical models of magnetization loss. When the field is parallel to the tape plane, the filaments in twisted tapes can be decoupled and the AC loss is decreased even when the matrix is pure silver. The extra effect of higher-resistance matrix materials is studied. In perpendicular field it is more difficult to decouple the filaments, due to the particular tape geometry. Contrary to a wire, there are essential differences between the AC loss mechanisms in a long twisted tape and those in a short piece of non-twisted tape. Finally, the dynamic resistance caused by the AC magnetic field is examined. 相似文献
7.
8.
9.
10.
It is necessary to develop HTS conductors with a large current capacity and low AC loss characteristics for practical use of HTS power devices. For large capacity power applications, HTS tapes such as Bi-2223 tapes and YBCO coated conductors are assembled. So, it is important to evaluate the characteristics of current distributions in such assembled HTS tapes. However, an adequate measurement method has not been established. In this study, we have tried the development of an indirect measurement method to evaluate the current distributions in stacked HTS tapes. In this method, the current distributions are indirectly found from the results of the field distributions measured by a pickup coil located around the surface of the sample tapes. To confirm the accuracy and the sensitivity of this method, current distributions in a test conductor made of copper tapes are measured. Numerical and measured current distributions are compared. Using this method, the current distributions in stacked Bi-2223 tapes are measured at room temperature and 77 K. On the basis of the obtained results, the characteristics of the AC current distributions in the HTS tapes are discussed. 相似文献
11.
临界电流值是描述Bi2223高温超导带材性能的一个基本参数,在一定的温度条件下,Bi2223高温超导带材的临界电流是带材所在位置磁场大小和磁场方向的函数,其短样的临界电流值可以通过四引线法测量,单根超导带材的自场很小,磁场对临界电流的影响可以忽略.高温超导磁体的临界电流被定义成引发该磁体失超的最小电流,高温超导磁体的自场比单根超导带材的自场要大得多,磁体各个位置的磁场大小和方向各不相同,很难用理论的方法准确计算磁体的临界电流.对于高温超导磁体而言,除了磁场的影响因素以外,绕制磁体所用的超导带材自身的均匀性也是影响其临界电流的一个重要因素.本文对这两个因素进行探讨,并着重讨论高温超导带材自身的均匀性对临界电流大小的影响,本文的结论可以为高温超导磁体的设计、磁体绕制时带材的选择、磁体运行时安全工作电流的确定提供帮助. 相似文献
12.
13.
14.
Bi2 2 2 3银包套超导带材是研制高温超导磁体和高温超导强电应用的基础。文中就对高温超导磁体最大运行电流有重要影响的 Bi2 2 2 3银包套带材侧向弯曲形变进行了初步探讨 ,就不同的侧向弯曲率对超导带载流能力的影响进行了实验测试 ,并提出了提高 HTS磁体最大运行电流的方法。 相似文献
15.
在地面实验中磁约束等离子体推进器磁体系统是靠四个NbTi低温超导磁体提供磁场,现在设计依靠G-M制冷机传导制冷的由Bi2223超导带材绕制成的四个高温超导磁体替代以前的四个低温超导磁体.本文利用ANSYS有限元分析软件进行电磁计算,得出高温超导磁体的参数。 相似文献
16.
本文研究了使用Bi-2223/Ag超导带材制备超导闭合线圈的工艺及超导闭合线圈中电流衰减的特性.在闭合线圈焊接点的制作上,分别采用了超导焊接和普通焊锡焊接两种不同方法.通过测量闭合线圈中心点的磁场衰减过程,观察了这两种闭合线圈中电流衰减的特性.实验发现,使用超导焊接技术制备的闭合线圈,电流衰减与时间的自然对数成线性关系,在线圈局部受损伤的情况下,上述关系仍然成立;使用普通焊锡焊接方法制备的闭合线圈,电流衰减不存在上述关系,但也不是时间的e指数函数. 相似文献
17.
18.
《Physica C: Superconductivity and its Applications》2002,360(1-2):55-58
Reactivity of several oxide materials (OM) with BSCCO powder and oxygen diffusion through OM layer has been tested at temperature ≈840 °C in air. The OM (e.g.: BaZrO3, SrCO3, MgO and ZrO2) showing the low or no reactivity with BSCCO have been mixed (10 wt.%) with precursor powder and used for single-core tapes. Bi-2223/Ag/OM/Ag single-core tapes with oxide barriers made of BaZrO3, SrCO3, ZrO2 and Al2O3 have been also prepared by a standard powder-in-tube technique. The used OM in the direct contact with BSCCO influences the electrical properties of Bi-2223 phase differently. These is because the oxides react with BSCCO during the heat treatment and simultaneously affect the 2212→2223 phase transformation, the Bi-2223 grain growth and so also grain connectivity. SrCO3 powder has been evaluated as the best material from the point of no destructive effect on 2223 phase transport current property. The oxide barrier controls the oxygen diffusion during the tape heat treatment and simultaneously the HTS phase formation kinetics, its purity and content within the superconducting core. For single-core Bi-2223/Ag/OM/Ag tapes, the highest current density was measured for Al2O3 due to only slightly reduced oxygen diffusion through the barrier. 相似文献
19.
Michael Reissner Siegfried Schwaiger Walter Steiner Wolfgang K?nig Gerhard Gritzner 《Czechoslovak Journal of Physics》1996,46(Z3):1561-1562
From magnetic relaxation measurements on monocore Ag-sheathed Bi-2223 tapes a phase diagram for flux creep is proposed. With
increasing field and temperature a phase transition from 2D single vortex creep to 2D collective vortex creep is found. Both
the phase transition and the irreversibility line are shifted to higher temperatures for samples with higher transport critical
current density. 相似文献
20.
对于一种Bi-2223的复合导体,利用ANSYS软件,我们分析了在直流磁场下励磁过程中,自场损耗对复合导体热稳定性的影响;然后假定Bi-2223超导带内不同的损耗值,通过计算,确定了达到超导带分流温度的最小损耗值。 相似文献