动力学研究AlN/α-Al2O3(0001)薄膜生长初期的吸附与扩散

采用基于第一性原理的从头计算分子动力学方法,计算了300-800℃下AlN吸附过程与系统能量、动力学轨迹以及扩散系数.研究表明,吸附过程由物理吸附、化学吸附和表面稳定态三个阶段组成,在吸附成键过程中,温度越高,粒子平均表面扩散能力增强.N原子的扩散系数大于Al原子的扩散系数,尤其是在物理吸附阶段.在较高温度条件下(大于700℃),N的解吸附作用明显增强,不利于AlN的稳定吸附生长,500-700℃之间的温度有利于AlN在α-Al2O3(0001)表面的稳定吸附生长.     

变步长非单调模式搜索法

A varied steplength nonmonotone pattern search method is proposed in this paper. The varied steplength search strategy is designed in this method such that the pattern direction is more approximated to efficient descent direction. The interpolation and nonmonotone technique are used for improving local search and global convergence. The theoretical and numerical results show that this method is an efficient direct search method.     

Development of New Capillary Electrophoresis-Based Techniques for Protein Analysis

With the sequencing of human genome almost complete, human genome project enters the postgenome-sequencing era. Compared to genomics, the analysis of proteome is rather difficult since in human cells there are around 200 000 proteins, which are expressed at any time at different levels     

交流调制磁场塞曼原子吸收分光光度计的研制

第一台商品塞曼原子吸收分光光度计(ZAAS,下同)日立170—70型是在1977年问世的。近十年来,这种仪器得到不断的改进和发展。我们在81年已研制出PZ—1型,现在,在该仪器和文献的基础上,又研制成功具有用视屏显示原子化过程     

乳清酸分析方法的研究进展

综述了近年来乳清酸分析方法的研究进展,内容包括紫外-可见分光光度法、荧光分析法、电化学分析法、色谱分析法、色谱-质谱联用法和量热法等几个方面,展望了乳清酸分析方法的发展方向.     

Synthesis and Crystal Structure of Potassium triaqua（ethyleneamin—N,N,N‘,N’—tetraacetate）gadolinium（Ⅲ）pentahydrate

1 INTRODUCTION The chemistry of lanthanide (Ⅲ) complexes has a considerable history. The stereochemistry of the lanthanide (Ⅲ) complexes with ethyleneamine- N, N, N, N-tetraacetate (Edta) has been investigated[1~10]. Up to now, many Ln-Edta complexes with the chemical formulae of M[Ln(Edta)(H2O)m]nH2O (M = Na+, K+, Cs+, NH4+, Guanium; m = 2, 3; n = 0, 1, 3, 5) have been reported and suggested that the coordination modes and crystal systems for the Ln-Edta complexes depend on …     

乳清酸/异乳清酸体系荧光法测定铕、铽、镝

对比研究了乳清酸和异乳清酸对某些稀土离子特征荧光的增敏情况，发现异乳清酸比乳清酸更有效地使Eu^3 、Tb^3 、Dy^3 的特征荧光增敏。建立了乳清酸，异乳清酸体系荧光法测定Eu^3 、Tb^3 、Dy^3 的新方法，在乳清酸体系中Eu^3 、Tb^3 、Dy^3 的检出限分别是0．73、0．065mg，L，在异乳清酸体系中Eu^3 、Tb^3 、Dy^3 的检出限分别是0．88、0．0023、0．59mg/L。该方法用于混合稀土氧化物中Eu^3 、Tb^3 、Dy^3 含量的测定，结果满意。     

β 沸石中铝的状态及归属

The states of aluminum in zeolites β were investigated with FTIR spectroscopy. Three kinds of aluminium, framework, nonframework and transient state aluminium, were detected in template-removed zeolite β. The states of aluminium in our samples strongly depends on the nature of the compensating cation, consistent with Brougeat-Lami et al's conclusion. But some new assignments of aluminum species and new opinions about the states of aluminum and their transformation are proposed. From the experimental results, we suggest that, the distortion and tension of zeolite lattice occur when protons, which possess high electron affinity , are located at cationic sites, leading to the breakage of Al-- O bond and the removal of aluminium. The distortion is released when H+ is replaced by other cations (e.g. Na+ ) so that transient state aluminium can go back into the framework, while the cationic nonframework aluminium species enter the solution upon the ion-exchange.     

β沸石中铝的状态及归属

用FTIR方法对β沸石中铝的状态进行了研究．结果表明，在脱除模板剂的β沸石中存在着三种状态的铝，即骨架铝、非骨架铝和过度态铝．铝的存在状态与平衡阳离子的性质密切相关，当平衡阳离子为高电子亲和性的H 时，β沸石的骨架发生扭曲而具有较大的张力，使得Al-O键断裂，铝经过渡态移出骨架，成为非骨架铝．当H 被Na 等离子取代后，骨架形变得以缓解，过渡态铝重又恢复骨架四面体配位，而阳离子态的非骨架铝物种则被交换进入溶液．     

新型2,3-二氢-3-芳亚甲基-4-芳基-1,5-苯并硫氮杂革的合成及表征

在盐酸和乙醇存在下,苯乙酮、多聚甲醛以及N,N-二甲基甲酰胺进行Mannich反应,得到了Mannich碱;将其和1,2,4-三唑在水中反应,得到含有1,2,4-三唑的苯丙酮;然后,在哌啶和甲苯存在下,苯丙酮和苯甲醛进行羟醛缩合,得到一系列含有1,2,4-三氮唑的查尔酮;最后,在三氟乙酸的催化下,查尔酮和邻氨基硫酚发生亲核取代反应,然后脱水缩合,合成了一系列2,3-二氢-3-芳亚甲基-4-芳基-1,5-苯并硫氮杂革.其结构经IR,1H NMR,MS及元素分析确证.