Coupling losses in a rectangular multifilamentary superconducting composite

Coupling current losses between filaments of a superconducting multifilament composite subjected to a transverse varying field is highly dependent on the shape of the conductor. The ac loss is evaluated in a conductor of rectangular cross sectional area. It is shown that the loss per unit volume is somewhat different from the loss in an elliptical shaped composite of the same aspect ratio. In addition, the loss in the outer copper sheath is less sensitive to the aspect ratio than the inner filamentary region. Numerous experimental results are given on losses in as-received conductors and in conductors where the outer copper sheath has been partially removed. The anisotropy in the losses caused by a changing field perpendicular or parallel to the wide side of a conductor is in very good agreement with the theory.     

射频溅射法在CeO2/YSZ/Y2O3/NiW衬底上制备YBCO超导层

用射频溅射的方法在强立方织构的CeO2/YSZ/Y2O3/NiW衬底上制备了YBCO超导层. 温度、气压等因素对超导层的外延生长有重要影响. 在基片温度大于780 ℃, 气压在11～160 Pa之间, 都有NiWO4化合物生成;在退火吸氧过程中, 金属基底被氧化. 最终在温度780 ℃, 气压100 Pa的条件下, 制备出了纯（00l）取向的YBCO薄膜, 其平面内φ扫描半高宽小于10°, 超导转变温度为87.2 K, 传导电流为11 A.     

High Tc Superconducting Materials for Strong Current Applications： Approach at the First Stage

Strong current and large-scale application is the most important prospect of high Te superconductors （HTS）. Practical HTS samples in various forms have been produced with high critical currents operated at economic cryogenic temperatures. Engineering applications of those HTS materials have been studied with various HTS prototype devices. The applicable HTS materials produced in different forms are verified in this paper with regard to their strong current characterizations, and the HTS applications are summarized along with the HTS prototypes made.     

高温超导输电电缆的现状与发展

超导输电电缆具有截流能力大、损耗低和体积小的优点,是解决大容量、低损耗输电的一个重要途径。文章概括介绍了高温超导电缆的结构、电缆的损耗、低温冷却系统,以及中国科学院电工研究所等单位研制的75 m长高温超导电缆。文中还简要提出了高温超导电缆的应用领域和前景。     

MgB2超导材料的专利申请现状分析

针对MgB2超导材料的中国专利申请进行了相关分析,通过对专利申请量的统计分析,研究了MgB2超导材料领域的发展趋势;通过对国内外来华专利申请量的对比分析,研究了国内外来华申请量的发展趋势以及国内主要申请人的专利申请分布,为我国专利申请人今后制定专利申请以及保护策略提供参考.     

YBa_2Cu_3O_(7-y)超导体合成机理

采用 TG-DTA 热分析和 X 射线衍射相结合的方法,研究了由不同原料制取单一相 YBa2-Cu_3O_(7-(?))超导体的合成反应机理。试验结果表明,YBa2Cu_3O_(7-(?))的形成经历两个反应阶段,首先形成 BaCuO_2和 Y_2Cu_2O_5,随后这两个二元复合氧化物化合形成 YBa2Cu_3O_(7-(?))。各步反应温度受钡盐种类控制,采用 Ba(NO_3)_2原料,在750℃即可表现出超导性,T_c 达86K。     

两类镜象电流对的磁场

从磁场矢势出发,研究了两类镜象电流对磁场的特点,得出了这两类镜象电流对在其镜平面上激发的磁场的矢势和磁感应强度与镜平面的关系,以及其量值是一电流元激发磁场相应量的两倍的结论。进而讨论了上述结论在磁场镜象法和对称电流系统(如直螺线管和螺绕管)磁场分析中的应用。     

Interesting aspects of the analysis of resistivity in Li irradiated Bi-2212

Differently heat treated and 55 MeV Li³⁺ beam irradiated Bi₂Sr₂Ca₁Cu₂O_8+δ (Bi-2212) high temperature superconductors have been studied from the analysis of resistivity in the normal state as well as near the superconducting transition. For all the unirradiated and irradiated samples the so-called linear temperature dependence of the normal state resistivity, in a wide temperature range, can well be understood within the variable range hopping (VRH) conduction scenario. Near and above the bulk superconducting transition, the fluctuation enhanced conductivity (paraconductivity) analysis shows a noteworthy modification of the conduction process due to radiation induced defects.     

用正电子湮没技术研究新型高临界温度T_c超导材料Ba-Y-Cu氧化物

本文介绍用正电子湮没技术研究了具有高临界温度下T_c的新型超导材料Ba-Y-Cu氧化物。实验发现,在起始转变温度以下,正电子寿命减少与电阻随温度的变化曲线符合。在临界温度T_c处,出现了正电子寿命峰。