Melamine trisulfonic acid-catalyzed N-formylation of amines under solvent-free conditions

A highly convenient method for N-formylation of amines via treatment by formic acid in the presence of melamine trisulfonic acid as a catalyst has been developed. This method showed improvements over previous reports in terms of yield, reaction time and chemoselectivity.     

Hcp-icosahedron structural transformation induced by the change in Ag concentration during the freezing of （CoAg）561 clusters

The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimetallic clusters plays a key rolc in exploring new structural materials. In this paper, we study the influence of Ag concentration on the frozen structure of the （AgCo）561 cluster by using molecular dynamics simulation with a general embedded atom method. The results indicate that tt~e structure and chemical ordering of the （AgCo）561 cluster are strongly related to Ag concentration. Hcp-icosahedron structural transformation in the frozen （CoAg）561 cluster can be induced by changing Ag concentration. The chemical ordering also transforms to Janus-like Co Ag from core-shell Co-Ag.     

高电荷态离子40Arq+与Si表面作用中的电子发射产额

报道了在兰州重离子加速器国家实验室电子回旋共振离子源原子物理实验平台上，用高电荷态⁴⁰Ar^q+(1≤q≤12)离子作用于半导体Si固体表面时的电子发射产额实验测量.实验中，通过改变炮弹离子的电荷态和引出电压选取其不同的势能和动能，系统地研究了入射离子势能沉积和与其在固体中的电子能损对表面电子发射产额的贡献.结果表明，作为引起表面电子发射的两个主要因素，单离子的电子发射产额与炮弹离子在固体表面的势能沉积和电子能损都有近似的正比关系.     

氮化铟p型掺杂的第一性原理研究

采用基于密度泛函理论(DFT)的总体能量平面波超软赝势法，对Mg，Zn，Cd掺杂InN的32原子超原胞体系进行了几何结构优化，从理论上给出了掺杂和非掺杂体系的晶体结构参数，其中非掺杂体系的理论值与实验值符合很好. 计算了掺杂InN晶体的结合能，总体态密度、集居数，差分电荷密度，并对此做了细致的分析. 计算结果表明，相对于Zn和Cd，Mg_In在InN中的溶解度会更大，并能提供更多的空穴态，非常有利于InN的p型掺杂. 关键词： 氮化铟 p型掺杂 电子结构 第一性原理     

并行小波滤波器

给出并证明了一种并行滤波器的设计算法．提出和论述了并行小波滤波器的基本设计方案．设计中采用了多种并行处理技术．