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排序方式: 共有57条查询结果,搜索用时 31 毫秒
1.
W. M. Chen W. Chen S. H. Zhou H. Y. Ling S. S. Jiang 《Journal of Superconductivity》2003,16(3):495-499
Multifilamentary Bi-2223 tapes were fabricated by PIT, using a silver alloy sheath with 2.5% magnesium metal. Outgrowth and bridging are major disadvantages for some silver alloy sheathed Bi-2223 tapes. To solve the outgrowth problem, green tapes were pressed with different reduction rates and then sintered at high temperatures. Critical current I
c of the sintered tapes was measured at nitrogen temperature using the four-probe method. The morphology of the filament core was observed with scanning electron microscope (SEM) to investigate outgrowth of sintered tapes with different reduction rates. Outgrowth and bridging on cross and longitudinal sections of filaments were studied using TEM images. Experimental results suggest that pressing processing may diminish outgrowth and bridging. Number of outgrowths and cases of bridging are reduced when the reduction rate increases, but the slope of the reduction falls at large reduction rates. The I
c curve indicates that there is an optimum reduction rate at which I
c reaches a maximum. At the best reduction rate the amount of outgrowth and bridging is close to the lowest. Experimental results show that pressing processing can diminish outgrowth and bridging by as much as 50%. Therefore, proper pressing is an effective method for both diminishing outgrowth and bridging and enhancement of I
c. 相似文献
2.
3.
实用Bi系高温超导带材 总被引:10,自引:0,他引:10
介绍了(Bi,Pb)2Sr2Ca2Cu3Ox(BSCCO)带材产业化生产技术,并就几个理、导线的机械加工以及带材的形变热处理等作了详尽的阐述,比较了世界各国的发展现状.针对特定的高温超导应用方向如超导电缆、超导磁体和电流引线等,研究了提高长导线均匀性的关键技术,进行BSCCO导线的多样化设计以降低导线的交流损耗、热导率和临界弯曲半径,并对导线进行表面改性处理如涂镀绝缘漆和镀锡等.结合已有的研究基础,从提高BSCCO带材的性能和降低生产成本出发,指出了BSCCO带材产业化技术今后的发展方向. 相似文献
4.
Advances in processing of superconductors has demonstrated that ceramic powders with exact composition, super-homogeneity,
and extremely fine particle size can be prepared by chemical processing to achieve high density and uniform microstructure.
The chemical processing routes have great advantage in preparing powder with high reactivity thus promoting solid state reactions
required to produce ‘purer’ superconducting phase. We have studied extensively the coprecipitation technique for the preparation
of superconducting ceramic powders. Chemical solution methods have been used in order to model several superconducting systems
and to predict optimum conditions for obtaining exact composition. Several improvements on the control of precipitation reaction
have been implemented in order to obtain powders of few nanometers in size. This has been done by carrying out the reaction
in the bulk of a solution or in microemlusion systems. The corecipitated precursor powder has been used for production of
20− 30 meter long Ag-clad tapes. These tapes require considerably reduced processing times. By controlled heat treatment conditions,
these tapes have been processed to carry transport critical current density, Jc <4 × 104 A/cm2 at 77K in zero applied field. 相似文献
5.
A. N. Iyer S. Salib M. Mironova C. Vipulanandan U. Balachandran K. Salama 《Journal of Superconductivity》1998,11(5):533-543
The powder-in-tube technique consisting of industrial processes such as wire drawing and rolling has been widely used to fabricate superconducting tapes. In the present investigation a novel technique was adopted to fabricate BSCCO 2223 tapes. Instead of wire drawing, the silver billet was reduced in size by groove rolling. Stress conditions during groove rolling were analyzed and appropriate changes were incorporated to optimize the deformation process. Subsequent thermomechanical treatment resulted in tapes with average critical current densities of 18,000 A/cm2. Phase development and microstructural evolution during the thermomechanical treatment were studied using XRD, SEM, and TEM. The electromechanical properties of monofilament and composite BSCCO tapes were evaluated by subjecting them to in situ tensile tests. The strain tolerance of the composite was found to be better than that of the monofilament BSCCO tape. 相似文献
6.
基于混合高温超导储能系统的电网动态功率补偿策略与试验 总被引:2,自引:0,他引:2
为实现高温超导储能系统(SMES)对电网功率波动的动态补偿,采用第1代铋系和第2代钇钡铜氧高温超导材料,设计并构建了过冷液氮温区运行、千焦级容量的混合高温超导储能系统。应用数字信号处理器和微控制器的双处理器形式,设计了LCL滤波的电压型SMES变流器的功率控制系统电路,基于空间矢量脉冲调制法(SVPWM),提出了SMES变流器对系统功率补偿的控制方法,并进行控制软件编程,实现对并网侧功率的动态监测和补偿策略的实时计算。最后应用SMES在一条200km输电线路上进行并网动模试验,针对电网负荷变化产生的功率波动状态,实现了毫秒级内对电力系统的快速功率输出和波动抑制,验证了超导储能系统对电网瞬时功率补偿策略和功率补偿变流装置的有效性。 相似文献
7.
《低温学》2018
We have investigated the microstructure and the magnetoresistivity of bismuth based superconductor bulks added with nano-sized CoFe2O4 particles (10 nm in diameter). Samples were prepared through the solid state reaction (SSR) technique by addition of CoFe2O4 nanoparticles during the last step of heat treatment. Phase examination using X-ray diffraction (XRD), morphology investigation by scanning electron microscope (SEM), microstructure and local chemical composition analyses using transmission electron microscope (TEM) coupled with energy dispersive X-ray spectroscope (EDXS), electrical resistance versus temperature ρ(T) under applied magnetic fields (B) and electrical resistance versus B at 77 K, ρ(B), were carried out. The CoFe2O4 added sample shows a great magnetoresistance to weak magnetic field at the temperature of liquid nitrogen (77 K). This result is attractive for practical, because CoFe2O4 added samples can be utilized as active elements in magnetic fields sensor devices. 相似文献
8.
9.
研究了采用单靶控溅射在Si(100)衬底上生长YSZ(钇稳定的ZrO2)BSCCO(铋锶钙铜氧)薄膜的工艺条件,包括生长温度,生长气氛,生长速率及氧化退化等。还研究了高温超导相的形成与生长温度的关系,并获得了超导膜临界温度为82K的BSCCO/YSZ/Si兼容材料。 相似文献
10.
The changes in volume of superconducting high-T
c (2223) phase of the high-temperature superconductors (HTSC) with nominal composition Bi3.2Pb0.8Sr4Ca5Cu7O
x
are studied by magnetic susceptibility during soaking of material in water and more aggressive aqueous solutions. The apparent volumes of the 2223 superconducting phase after long-term (168 hr) soaking in H2O, NaCl(aq), and NaOH(aq) decreased to 22%, 17%, and 57%, respectively. The atomic absorption analysis of resulting solutions showed high amounts of Sr2+ and Ca2+ in H2O and NaCl(aq) and lower amounts of Sr2+ and Ca2+ in NaOH(aq). The highest content of Pb2+ and Cu2+ was detected in NaOH(aq). 相似文献