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The crossover from parallel shift to fan-shape broadening of the superconducting transition of La(1.44)Nd(0.4)Sr(0.16)CuO(4) films in magnetic fields

Superconductor Science & Technology

In this paper we report the transport properties of c-axis-oriented superconducting La(1.44)Nd(0.4)Sr(0.16)CuO(4) films on LaSrAlO(4) substrates with different thicknesses in various magnetic fields parallel and perpendicular to the c axis of the films. It is found that with decreasing film thickness there is a crossover from the parallel shift to fan-shape broadening in the resistive transitions. Moreover, for both field configurations, the flux pinning potential U(0)(H) of the film shifts upward with an order of magnitude with increasing in-plane compressive strain. These results indicate that the compressive epitaxial strain and strain-induced destabilization of the static charge stripes are important aspects for the promotion of superconducting transition temperature as well as the flux pinning potential.

关键词: high-temperature superconductors;crystal thin-films;flux motion;la2-xsrxcuo4;strain;insulator;dependence;behavior

Deformation-induced gamma -> DI-alpha(2) phase transformation occurring in the twin-intersection region of TiAl alloys

Journal of Materials Research

Deformation-induced gamma -> DI-alpha(2) phase transformation was verified to occur in the twin-intersection region of a Ti-45Al-8Nb (at.%) alloy compressed at room temperature. High-resolution image observations of the deformation-induced DI-alpha(2) phase suggested that the orientation relationship between the DI-alpha(2) and gamma phases remained the typical one: (0001)(DI-alpha 2)//{111}(gamma), [11 (2) over bar0](DI-alpha 2)//< 101]gamma. The conversion of stacking sequence from ordered face-centered tetragonal to ordered nonequilibrium hexagonal close-packed structure was accomplished by the movement of a/6 < 11 (2) over bar] Shockley partial dislocations on every other {111}(gamma) plane. Compositional analysis based on energy dispersive spectra revealed that the DI-alpha(2) phase had the same composition as the matrix gamma phase. No compositional diffusion Occurred because the plastic deformation was carried out at room temperature. The strong stress concentration in the intersection region was the major force to induce the gamma -> DI-alpha(2) phase transformation in the process of room-temperature compression.

关键词: titanium aluminides;mechanical-properties;room-temperature;microstructure;intermetallics;microscopy;nb

DI材横向厚差自动控制算法及其应用

徐江华 , 李山青

上海金属

DI材是宝钢的重要产品,主要用于碳酸饮料罐和啤酒罐.DI材沿宽度方向的厚度均匀性要求十分严格.为了减少DI材的横向厚差,开发了横向厚差自动控制系统并应用在某冷连轧机上.该控制系统使用了基于鲁棒性能指标(robustness specification)的横向厚差自动控制算法,从而使厚度0.229 mm以下的DI材的横向厚差被控制在±4μm以内.

关键词: DI , 冷轧 , 横向厚差 , 自动控制

高速电镀锡薄钢板(DI材)用气相缓蚀剂的研究

王新葵 , 罗广求 , 李宁

腐蚀与防护 doi:10.3969/j.issn.1005-748X.2005.05.003

采用气相快速甄别实验和电化学方法研究了对高速电镀锡薄钢板(DI材)具有缓蚀作用的四种不同的物质.结果表明:苯甲酸钠、苯甲酸铵、肉桂酸对DI材的阳极过程有明显的抑制作用;单纯的钨酸钠对DI材的缓蚀效果不佳.通过正交试验发现:苯甲酸钠、苯甲酸铵、肉桂酸与钨酸钠的复配使用,表现出很好的协同作用,从而得到了一种新的环保、高效的用于DI材的气相缓蚀剂配方.

关键词: 气相缓蚀剂 , 正交实验 , 协同作用

Growth Mechanism of Di®erent Morphologies of ZnO Crystals Prepared by Hydrothermal Method

Hu Wang Juan Xie Kangping Yan Ming Duan

材料科学技术(英)

Different morphologies of zinc oxide (ZnO), including microrods, hexagonal pyramid-like rods and flower-like rod aggregates, had been synthesized, respectively, on glass substrates by controlling the reaction conditions (such as precursor concentration, reaction time and pH value) of hydrothermal method. The morphologies of the as-obtained ZnO were observed with scanning electron microscopy and transmission electron microscopy.
Also, the crystalline natures of di®erent ZnO crystals were analyzed with X-ray diffraction. The possible growth mechanism of ZnO crystals with di®erent morphologies was discussed.

关键词: Zinc oxide

EFFECT OF PHOTOOXIDATION ON PHOTOLUMINESCENCE OF N, N'-DIPHENYL-N, N'-DI(M-TOLYL)-BENZIDINE AND RUBRENE CODOPED PMMA THIN FILMS

Y.B. Hou

金属学报(英文版)

In this paper, the PMMA films doped with N,N'-diphenyl-N,N'-di(m-tolyl)-benzidineand rubrene were fabricated by spin coating, and the effect of photooxidation onthe photoluminescence of the doped PMMA thin films was investigated. The resultsshowed that under the irradiation of 350nm UV light, N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine can sensitized rubrene and results in the enhancement in the photooxrationof rubrene. The effect of photooxidation on the photoluminescence from rubrene w asmore obvious. Both lifetime measurement and in situ measurement of photolumines-cence showed that rubrene molecules exist in two chemical surroundings.

关键词: photoluminescence , null

碳含量及终轧、卷取温度对DI材Δr值的影响

方百友

钢铁

对于低碳铝镇静钢DI材试验及统计分析结果表明,在一定范围内,碳含量增高,材质面内各向异性减小而趋向于均匀化;终轧温度升高,材质面内各向异性值则增大;卷取温度的影响亦具有类似的规律性.拉伸试验和断面金相分析结果进一步证实,较高碳含量和适当的热轧温度可抑制晶粒过分长大,缩小晶粒间差异,达到改善材质面内各向异性的目的.

关键词: DI , Δr , 碳含量 , 终轧温度 , 卷取温度

Di-An-Ab体系快速冷却结晶的枝晶研究

黄琼 , 赵珊茸

人工晶体学报 doi:10.3969/j.issn.1000-985X.2003.03.010

对透辉石-钙长石-拉长石(Di-An-Ab)三元体系在不同降温速度条件下形成的枝晶进行了研究.其中,透辉石枝晶为规则树枝状,主枝和分枝明显;斜长石枝晶呈放射纤维状集合.枝晶形貌随降温速度变快没有明显变化,枝晶晶体结构随降温速度不同而有改变,降温速度减小,透辉石枝晶晶胞参数a值呈增加趋势,b、c呈减小趋势,斜长石枝晶b值呈减少趋势,c值呈增加趋势,两者β值呈增加趋势,但改变不大.随着降温速度增大,透辉石枝晶、斜长石枝晶硅氧骨干中,铝硅比值增大,铝更大程度地替代硅.另外还发现,降温越快,枝晶结晶数量越少.

关键词: Di-An-Ab体系 , 枝晶 , 降温速度 , 枝晶形貌

Di-Ab-An体系远离平衡枝状形貌的演化及枝体结晶学各向异性特征研究

郭颖 , 赵珊茸 , 刘慧芳 , 蒋宏

人工晶体学报 doi:10.3969/j.issn.1000-985X.2005.04.017

对钠长石(Ab)-钙长石(An)-透辉石(Di)三元体系跨相界线的不同成分点在不同的降温速度条件下快速结晶形成的枝状形貌进行了研究.透辉石为枝晶,斜长石为球粒晶.当降温速度慢于1℃/min后,枝状形貌变为板-柱状形貌(即近平衡形貌).我们的实验结果中没有观察到如E.Brener 和H.Muller等人提出的形貌演化图一样的演化规律.当成分点靠近同结线后,出现两晶共结形成的"中空结构".通过光学显微镜下测试其光学性质发现,透辉石沿c轴方向延长,斜长石沿a轴延长,与晶体结构中的强键链方向一致,即快速结晶时晶体沿着结构中负离子配位多面体共角顶、共棱形成的强键链方向生长形成枝体.

关键词: Di-Ab-An体系 , 枝状形貌 , 各向异性 , 结晶学方向

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