黄爱琴
,
李国勋
,
马淑兰
,
李国斌
,
余忠勤
材料研究学报
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。
关键词:
YBa_2Cu_3O_(7-γ)
,
superconductor
,
synthetic mechanism
,
TG-DTA thermal analysis
,
X-ray diffraction
田陆
,
王文皓
,
龚沿东
,
孙玉珍
,
林树智
金属学报
在LAS3000表面分析系统中用自制的低温样品台和清洁样品刮刀,获得了室温和130K下表面清洁的 YBa_2Cu_?O_(7-x)的X射线光电子谱。对超导与非超导样品中各元素的内层能级X射线光电子谱线进行分析比较.Ols出现双峰,其中高结合能峰属于O1,O4,低结合能峰属于O2,O3.室温下非超导样品的O2,O3高于-2价,Cu略低于+2价共价性极强,Y和Ba呈正常价态;低温下各元素价态无明显变化.室温下超导样品的O2,O3为-2价,Cu平均价高于+2价,离子性较强,存在Y和Ba的低价离子;低温下部分O2,O3价态升高,Cu价基本不变,Y和Ba的价进一步降低.两种样品中O1,O4价态绝对值都很低,反映了周围点阵缺陷的存在。
关键词:
超导体
,
superconductor
,
low temperature
Present address:Hengyang Institute of Technology. TIAN LU WANG Wenhao GONG Yandong SUN Yuzhen LIN Shuzi Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
The XPS spectra of superconducting(123-orthorhombic structure)and non-superconducting (123-tetragonal structure)YBa_2Cu_3O_(7-x)ceramics were obtained at room temperature and 130 K with RIBER LAS 3000 surface analysis system,in which a sample cooling stage and a surface cleaning scraper,both made by the authors,were installed.No evidence of Cu~(3+)was found.The O 1s shows double lines.They are attributed to O1 and O4 with higher binding en- ergy and to O2 and O3 with lower binding energy respectively,and it was confirmed by cal- culation of SW-X_α method.The differences and changes in valence states of Y,Ba,Cu and O in both samples were discussed.
关键词:
YBaCuO
,
null
,
null
,
null
Junhua LIU+
,
Dept. of Manufacturing Engineering
,
Beijing University of Aeronautics and Astronautics
,
Beijing 100083
,
ChinaZutang WANG
,
Dept. of Mechanical Engineering
,
Tsinghua University
,
Beijing
,
100084
,
China
材料科学技术（英）
The effects of sintering on the microstructure and the critical current density of Ag-sheathed BiPbSrCaCuO (2223) superconducting tapes prepared by the powder-in-tube technique were in- vestigated. The microstructure of oxide layer and the J_C at 77 K were strongly dependent on the sintering condition. The optimum sintering temperature, time and cooling rate to maximize J_C values were in the range about 840-850℃, 100-200 h and 50-100℃/h, respectively.
关键词:
BiPbSrCaCuO
,
null
,
null
,
null
刘欢
,
周鹏博
,
李兴田
,
张涵
,
杨晨
,
陈红
,
王睿
,
王箴
,
李楠
低温物理学报
超导体-铁磁体超材料在静磁场中具有有效的磁屏蔽特性.大部分超材料都是由超导材料和铁磁材料组成,而这种材料的性能主要取决于构成材料的结构,几何尺寸及每种材料的磁导率.本论文将麦克斯韦方程和超材料的设计结合起来,提出一种超导体-铁磁体超材料系统.该系统由两种材料的同轴圆柱体构成,我们研究该系统在直流磁场环境下的屏蔽特性.通过改变屏蔽圆柱体的几何尺寸,我们计算出屏蔽效能从而得到最优屏蔽结构.本论文的工作旨在为核磁共振成像及降低医学器械中的磁场特性提供有效的理论依据.
关键词:
超导体
,
铁磁体
,
超材料
,
屏蔽
W.GAOZ.W.LI
中国腐蚀与防护学报
Oxidation of metallic components often results in degradation and structural failure, prevention is therefore an important topic. On the other hand, oxidation process creates new products such as metal oxides, can be used as a production route. A well-known process in semiconductor industry is that oxidation in dry or wet atmosphere is a popular way for growth of multi-functional SiO2 films on Si wafers. Recently, oxidation processes under controlled conditions (atmosphere, temperature, and time) are used to prepare various oxides, carbides, or nitrides with micro-/nano-structures, well-defined composition, dimension, shape and properties. The use of oxidation now includes thin film and nano-/micro-sized devices, and porous oxides for sensing and catalysis purposes. This paper introduces the research activities in the authors' group on applications of oxidation as a tool for synthesis of functional materials.
关键词:
oxidation
,
null
,
null
,
null
