ZHANG Cheng
,
WANG Yongzhong
,
JIANG Ming
,
ZENG Dechang
,
TANG Hong
,
LI Zhongrun
,
QIAO Guiwen
,
CHUANG Yuzhi(Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
ChinaManuscript received on 20 April 1995)
金属学报(英文版)
Bi-2212 superconductive oxides with nanometer grains have been prepared by means of crystallization from amorphous materials.The structure and grain-size of samples were examined by.X-ray.diffraction,scanning electron microscopy.and high resolution electron microscopy.The temperature dependence of the resistivity.and a.c.susceptibility was measured by the standard four-probe method and the standard mutual-induction measurement,respectively.With the decrease of temperature,the resistivity of the Bi-2212 phase with grain size in nanometer was found to diminish to zero without sudden drop.No diamagnetic transition was detected from room temperature to 4.2 K.The formation of the nanocrystalline 2212 phase and the effect of grain size on the superconductivity were discussed.
关键词:
:Bi-2212
,
null
,
null
,
null
TANG Hong
,
XIANYU Ze
,
HU Qianli
,
QIAO Guiwen
,
WANG Yongzhong
,
ZHUANG Yuzhi1 1) Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China 2) Northeastern University
,
Shenyang
,
China Manuscript Received 7 March 1995
金属学报(英文版)
In this study, high-Tc YBaCuO superconductors with high Jc value were prepared using MTG(melting-textured growth) method. These superconductors with high density have Jc value in excess of 1.6×104 A/cm2 (77K, zero field) determined by using a d.c. standard four terminal method with the criterion of lμV/cm. The XRD and fractograph analysis revealed that the texture existed in whole MTG-processed YBaCuO sample which consists of the layered and plate-like grains of matrix phase YBa2Cu3Oy unidirectionally aligned along its (103) planes. The experimental results indicated that the connectivity between superconducting grains has been improved greatly and the weak-link problem has been overcome essentially.
关键词:
: YBaCuO high-Tc superconductor
,
null
,
null
,
null
TANG Hong
,
QIAO Guiwen
,
CHUANG YuchiInstitute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
ChinaXIANYU Ze
,
WANG JinxingNortheastern University
,
Shenyang
,
China
金属学报(英文版)
In present paper, study of magnetization behaviour was carried out for textured bulk YBaCuO polycrystalline superconductors synthesized by MTG process. The magnetization behaviour apparently different from that of sintered samples was observed. Magnetization hysteresis measurements were performed for the textured YBaCuO superconductors at 77K in± 10kOe magnetic field range. Based on the results of magnetization hysteresis, the magnetic field dependence of critical current density (Jc) at 77K was evaluated for the textured YBaCuO samples. The magnetic flux penetration in textured bulk YBaCuO polycrystalline superconductors was investigated at 77K through the magnetization hysteresis measurements under various maximum applied magnetic fields (HM) and reasonable discussion for the phenomena was conducted in terms of Bean's critical state model. The enhancement of magnetic properties for textured hulk YBaCuO polycrystalline superconductors is presumably attributed to the improvement of microstructure in these samples.
关键词:
YBaCuO polycrystalline superconductors
,
null
,
null
,
null
,
null
TANG Hong
,
LI Jingmin
,
YAO Biqiang
,
LIAO Hongfu
,
YAO Jin
钢铁研究学报(英文版)
Blast furnace scheme design is very important, since it directly affects the performance, cost and configuration of the blast furnace. An evaluation approach to furnace scheme design was brought forward based on artificial neural network. Ten independent parameters which determined a scheme design were proposed. The improved threelayer BP network algorithm was used to build the evaluation model in which the 10 independent parameters were taken as input evaluation indexes and the degree to which the scheme design satisfies the requirements of the blast furnace as output. It was trained by the existing samples of the scheme design and the experts′ experience, and then tested by the other samples so as to develop the evaluation model. As an example, it is found that a good scheme design of blast furnace can be chosen by using the evaluation model proposed.
关键词:
blast furnace;artificial neural network;scheme design
