Han Chen Kui Cheng Zhicheng Wang Wenjian Weng Ge Shen Piyi Du Gaorong Han
材料科学技术（英文）
Porous NiO-Ce0.8Sm0.2O1.9 (NiO-SDC) ceramics with homogeneous pore distribution were prepared using polystyrene (PS) spheres as pore templates. NiO-SDC powders were synthesized by a glycine-nitrate method, ultrasonically mixed with PS spheres in ethanol, dried and then pressed into green pellets. The pellets were sintered to yield porous NiO-SDC ceramics. The effects of the sintering temperature on the microstructure and mechanical strength of the ceramics were investigated. NiO-SDC ceramics sintered at 1200 and 1350°C have interconnected pore structures and high compression strength. When single cells were fabricated using porous NiO-SDC ceramics as anode-supported layers, the peak power density of the cells at 600°C was 333 and 353 mW·cm-2 for ceramics sintered at 1200 and 1350°C, respectively. The results indicated that these porous ceramic materials are promising for anode substrates for solid oxide fuel cells.
关键词:
Porous ceramic
,
NiO-SDC
,
聚苯乙烯球
,
微观结构
,
阳极支撑固体氧化物燃料电池
郑桂丽
,
姜丽
,
张志东
液晶与显示
doi:10.3969/j.issn.1007-2780.2010.06.001
根据Erickson-Leslie流体动力学理论,研究了混合排列向列相-共面转换液晶盒的引流效应.在强锚定边界条件下,经过理论推导,得出液晶指向矢与流速的关系方程,进一步通过数值计算得出指向矢分布与时间的关系.发现引流效应加快了指向矢达到平衡态的速度,而且破坏了指向矢分布的瞬态对称性,特别在加电压的初始几毫秒这种现象非常明显.
关键词:
混合排列向列相
,
共面转换
,
引流效应
,
指向矢分布
严东旭
,
刘天伟
,
龙重
,
白彬
,
张鹏程
,
黄河
,
郎定木
,
王晓红
,
朱建国
材料保护
采用单一的表面改性技术难以提高贫铀钛合金(Du-Ti)的耐蚀性能.采用等离子体浸没离子注入技术依次在Du-Ti合金表面注入N和Ti,再利用非平衡脉冲磁控溅射技术制备多层Ti/,TiN,研究了膜层的形貌、结构及耐蚀性能.结果表明:膜层厚约3μm,呈柱状结构,致密,但存在一些微缺陷,膜基结合紧密;膜层出现面心立方结构的TiN和密排六方的Ti,在DU-Ti合金界面形成了少量的UO2,没有铀的氮化物;膜层耐蚀性能较基体得到较大提高;微观缺陷是TiN层局部片状脱落的主要原因,外层TiN出现片状脱落后.注入层和内层Ti/TiN多层膜仍能有效保护基体.
关键词:
等离子体浸没离子注入
,
非平衡磁控溅射
,
复合膜
,
DU-Ti合金
,
电化学腐蚀
,
耐蚀性
李开明
,
李亚洲
,
冯维贵
,
林长
量子电子学报
doi:10.3969/j.issn.1007-5461.2007.05.014
采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.
关键词:
混沌
,
Chen系统
,
不动点
,
Lyapunov指数
,
反馈控制
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
LIU Shuqi
,
YI Tao
,
Peking University
,
Beijing
,
China
金属学报(英文版)
The diagram of Ag-Cu-Ge system was constructed from the investigation of 13 internal sec- tions by DTA heating as well as cooling curves in an atomsphere of dry N_2 . The phase dia- gram is subdivided into two pseudo-ternary systems shown as Ag-Cu-Cu_3Ge and Ag-Cu_3Ge-Ge. Both systems belong to simple eutectic type. The ternary eutectic points lie in." E_1, Ag(22.0)-Cu(58.8)-Ge(19.2), 632℃ and E_2 , Ag(44.3)-Cu(29.5)-Ge(26.2), 533℃. The three side binary systems were redetermined.
关键词:
phase diagram
,
null
,
null
Journal of Alloys and Compounds
Crystal structures of compounds at ambient temperature in the pseudobinary system Gd5Ge4-La5Ge4 were studied by X-ray powder diffraction (XRD). There exist three single-phase regions in this system. The crystal structure of Gd5Ge4, La5Ge4 and Gd3La2Ge4, which are prototype compounds in three phase regions, respectively, were reported. The Gd5Ge4 and La5Ge4 crystallize in the orthorhombic Sm5Ge4-type structure with space group Pnma. The ternary intermediate compound Gd3La2Ge4, which is determined for the first time, crystallizes in the monoclinic Gd5Si2Ge2-type structure with space group P112(1)/a. The Rietveld powder diffraction profile fitting technique was used for the refinement of crystal structure. The lattice parameters, atomic occupations, interatomic distances of the Gd5Ge4, La5Ge4 and Gd3La2Ge4 compounds were derived. (C) 2003 Elsevier B.V. All rights reserved.
关键词:
rare earth compounds;crystal structure;X-ray diffraction;phase-relationships;gd-5(si2ge2);transition;silicon
