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Macroscopic Studies on the Properties of the Anodic Oxide Films on Titanium

G.A.EL-Mahdy (Chemistry Dept. , Faculty of Science , Helwan University , Helwan , Cairo , EgyptS-S.MahmoudChemistry Dept. , University College for Women , Ain-Shams University , Helopolis , Cairo , Egypt)

材料科学技术（英文）

The effect of fluoride ions on the formation and dissolution behaviour of anodic oxide films on Ti has been investigated in acidic fluoride media (pH=1) using impedance and galvanostatic techniques. A5 the fluoride ion concentration and temperature increase the rate of oxide film formation decreases while the dissolution process increases. oxide film formed at high tem-perature and formation voltage was found to contain more defect sites in the film than that formed at a lower one. Activation energies are calculated during the oxide film formation and dissolution and found to be 20.76 and 28.72 kJ/mol, respectively. Formation rate and reciprocal capacitance data are reported as a function of polarizing current density. Values are recorded for the electrolytic parameters A and B. Potentiostatic curves are derived from the galvanostatic results.

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用DEPT135测定Resol的组成及微细结构参数

杨金瑞 , 余尚先 , 顾江楠

高分子材料科学与工程

通过对resol(羟甲基酚化合物和低分子量羟甲基酚树脂)DEPT135图谱的分析讨论,得到一系列计算resol微细结构参数的经验公式.根据DEPT135图谱可判断是否发生缩聚反应,根据经验公式可计算酚单体各个活性点参与反应百分率或酚羟基导入率、不同类型缩聚所占百分率及低分子量羟甲基酚树脂的平均核体数.

关键词: 羟甲基酚化合物 , 羟甲基酚树脂 , DEPT135 , 结构参数

有机EL和LED与无机EL和LED发光机制的异同

李文连

液晶与显示 doi:10.3969/j.issn.1007-2780.2001.01.007

比较了有机EL和LED与无机EL和LED的主要差异。有机EL属于电注入发光，无机EL属于高场激发下的碰撞离化机制，而且有机LED和无机LED的激发和发光机制也不同。无机半导体中往往存在着局域载流子，而有机LED必须从电极注入，在未注入载流子之前，它们是绝缘体。不能简单地用无机LED中的p-n结理论来解释有机LED的发光现象。

关键词: 有机电致发光 , 半导体 , 发光

有机EL与无机EL和LCD的比较及其未来前景

李文连

液晶与显示 doi:10.3969/j.issn.1007-2780.2002.01.005

通过比较有机EL与无机EL、LCD在平板显示应用方面的差异,展示了OELD的美好应用前景.由于无机薄膜EL缺乏高亮度蓝基色成分以及驱动电压是100V左右的交流,难于制成低压彩色超薄显示器;无机分散型EL屏采用的是十几微米厚的粉末材料,也难于制成高分辨率超薄显示器,因此它们都无法与OELD相比.OELD显示器体积可以是LCD的1/2,功耗也大大低于LCD,所以OELD将有望取代LCD.评述了当前OELD的最新发展趋势:采用荧光染料掺杂式的模糊界面结构的电致荧光器件和采用荧光染料掺杂式的电致磷光器件是当前OELD发展的主要潮流.文中还评述了采用低折射率材料提高外量子效率的情况.

关键词: 电致发光 , 磷光 , 发光平板显示

用于有机EL器件的电极材料

李文连

液晶与显示 doi:10.3969/j.issn.1007-2780.2000.02.005

由于有机EL属于电注入发光,因而电极材料在EL器件的载流子注入中起着重要作用,但这往往被人们所忽略.本文描述了正负电极材料的功函数、电极材料及结构等对EL器件性能有着重要影响,并对电极材料工作机制进行了讨论.

关键词: 电极材料 , 有机电致发光器件 , 聚合物

Metal-Free Heterogeneous Catalysis for Sustainable Chemistry

Chemsuschem

The current established catalytic processes used in chemical industries use metals, in many cases precious metals, or metal oxides as catalysts. These are often energy-consuming and not highly selective, wasting resources and producing greenhouse gases. Metal-free heterogeneous catalysis using carbon or carbon nitride is an interesting alternative to some current industrialized chemical processes. Carbon and carbon nitride combine environmental acceptability with inexhaustible resources and allow a favorable management of energy with good thermal conductivity Owing to lower reaction temperatures and increased selectivity, these catalysts could be candidates for green chemistry with low emission and an efficient use of the chemical feedstock This Review highlights some recent promising activities and developments in heterogeneous catalysis using only carbon and carbon nitride as catalysts The state-of-the-art and future challenges of metal-free heterogeneous catalysis are also discussed.

关键词: carbon;catalyst;heterogeneous catalysis;selectivity;sustainable;chemistry;graphitic carbon nitride;modified activated carbon;nanofiber/graphite-felt composite;ordered mesoporous carbons;oxygen;reduction reaction;nitrogen-doped graphite;fuel cell cathode;onion-like carbon;oxidative dehydrogenation;hydrogen-production

有机EL器件的研究及产品开发现状

张素梅 , 石家纬 , 李靖

液晶与显示 doi:10.3969/j.issn.1007-2780.2004.01.008

介绍了有机EL器件的结构、工作原理及特点,概述了有机EL器件的研究现状及产品开发现状,对器件今后的发展做了展望.

关键词: 有机 , EL器件 , 产品开发

SERS and Quantum Chemistry Studies of Adsorption of Thiourea and Ethylthiourea on Silver Electrode

Acta Physico-Chimica Sinica

Adsorption of thiourea (TU) and ethylthiourea( ETU) on roughened silver electrode was investigated using in situ surf. enhanced Raman spectroscopy(SERS) Using quantum chemistry and HSAB theories, the influences of electrode potential and the different substituent groups on SERS were disc i. TU is chemisorbed perpendicularly by Ag-S bond on silver at E = -0.3 V and adsorption of TU turns into a parallel orientation at E = -0.9 V. ETU is always chemisorbed at an angle from Ag. The adsorption of ETU is through and C=C and C=O groups at E = -0.3 V, and mainly through C=C at E = -0.9V.

关键词: Surface enhanced Raman spectroscopy;Adsorption;Quantum chemistry;Thiourea;Inhibitor

LOCAL CHEMISTRY AND THE COHESIVE STRENGTH OF GRAIN BOUNDARIES IN Ni_3Al

Shanthi Subramanian , David Muller , John Silcox and Stephen L.Sass (Department of Materials Science and Engineering and Department of Applied and Engineering Physics , Cornell University , Ithaca. NY 14853)

金属学报(英文版)

Local chemistry plays an important role in determining the cohesive strength of grain boundaries in Ni3Al. Doping with B increases the room temperature ductility and changes the fracture mode from intergranular to transgranular, while doping with Zr increases the ductility but leaves the fracture mode predominantly intergranular.Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDS) were used to probe the changes in local bonding (and hence the cohesive strength) produced by changes in local chemistry at large angle boundaries in Ni3Al.In addition , small angle tilt boundaries were studied to correlate structure with Nienrichment at the interface. B segregation to Ni-rich grain boundaries was shown to make the bonding similar to that of the bulk, thereby increasing their fracture resistance. Ni-enrichment does not occur in the presence of Zr segregation to grain boundaries. Ni-enrichment to antiphase boundaries (APB) in small angle tilt boundaries lowers the APB energy by reducing the number of high energy Al-Al interactions across the interface. Ni-enrichment to large angle boundaries is expected to produce a similar effect on energy.

关键词: : grain boundary chemistry , null , null , null