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.     

微波灰化/DUO-ICP-AES测定残渣燃料油中的铝、硅、钒

采用微波灰化技术消解残渣燃料油,用全谱直读DUO-ICP-AES同时测定残渣燃料油中的铝、硅、钒,优化了仪器工作参数和实验条件.结果表明,在质量浓度0 ～25.0 mg/L范围内铝、硅、钒的线性关系良好(r=0.999 70 ～0.999 99),检出限、回收率和相对标准偏差分别为0.005 ～0.050 mg/L、8...     

COMPLETENESS FOR H_q~p(D) SPACE

Abstract Let D be arbitrary simply connected domain with at least two boundary points.We have introduced a kind of analytic functions' space H_■~V (D) (p≥1, q>0)and shown that it is a complete linear space with respect to the norm ■·||_(H_q~p(D)).     

EFFECT OF CRYSTALLIZATION TEMPERATURE ON MCM-41 SYNTHESIS

在Ｎａ２ＯＳｉＯ２ＣＴＡＢＨ２Ｏ四元水热体系中系统地考察了晶化温度对中孔ＭＣＭ４１分子筛合成及其骨架结构的影响。实验结果表明，提高晶化温度虽然能明显加快晶化速率，缩短晶化时间，但同时样品的结晶度和中孔骨架结构的有序度却被迅速破坏。这些特点与传统沸石的合成过程完全不同，其原因主要是合成ＭＣＭ４ｌ时所用的模板剂及其在合成中所起的模板作用与传统沸石完全不同。相对低的晶化温度（如１００℃）有利于高质量和高热稳定性的中孔ＭＣＭ４ｌ分子筛的合成。