V／Sb催化剂上丙烷氨氧化反应机理的Monte Carlo模拟

本文应用Ｍｏｎｔｅ Ｃａｒｌｏ方法对丙烷氨氧化的反应机理进行了初步研究。首先在分析了Ｖ／Ｓｂ金红石构催化剂的各个晶面之后，以１００面为模板建立了Ｖ／Ｓｂ双活性中心模型。在此基础上，对丙烷，氨及氧的不同进料摩尔比率对丙烯腈，丙烯及ＣＯＸ三种产物的影响规律进行了详细考察。     

Crystal Radii and Their Application on the Study of Electronic Structures of LaX(X=N,P,As,Sb)

以Ｐｈｉｌｉｐｓ－ＶａｎＶｅｃｈｔｅｎ理论和晶体光学性质为基础，计算了ＬａＸ（Ｘ＝Ｎ，Ｐ，Ａｓ，Ｓｂ）晶体的离子半径（单位：ｎｍ）：（Ｌａ：Ｎ）为（０．１４１４，０．１２３６），（Ｌａ：Ｐ）为（０．１５１８，０．１４８９），（Ｌａ：Ａｓ）为（０．１５３６，０．１５２６），（Ｌａ：Ｓｂ）为（０．１５８６，０．１６５１）．用ＬＭＴＯ－ＡＳＡ方法对ＬａＸ系列晶体的能带结构进行了计算．所得到的能隙是：ＬａＮ为２．３０ｅＶ，ＬａＰ为２．０５ｅＶ，ＬａＡｓ为１．６６ｅＶ，ＬａＳｂ为１．３４ｅＶ．与实验结果相符．这也证明了作者得到的半径的合理性．     

Ge2Sb2Te5的化学机械抛光研究进展

相变存储器由于具有非易失性、高速度、低功耗等优点被认为最有可能成为下一代存储器的主流产品,Ge2Sb2Te5(GST)作为一种传统相变材料已经被广泛应用在相变存储器中,而GST的化学机械抛光作为相变存储器生产的关键工艺目前已被采用.本工作综述了有关GST的化学机械抛光技术研究进展,讨论了GST化学机械抛光过程的影响因素,如下压力、转速、抛光垫、磨料、氧化剂、表面活性剂等,并对目前GST的化学机械抛光机理进行了归纳,进一步展望了GST的化学机械抛光技术的发展前景.     

First principles study of isostructural phase transition in Sb2Te3 under high pressure

The structural properties, electronic band structure and Bader charge of Sb₂Te₃ under hydrostatic pressure were simulated using density functional theory in order to study isostructural phase transitions (IPT) in Sb₂Te₃. The theoretical results showed that the axial ratio c /a did not exhibit any anomaly below 6 GPa. The variations of bond lengths were discontinuous at 2.5 GPa, which suggested considerable changes in interatomic interactions and provided sound support to the IPT. The effective charges of Sb and Te atoms showed significant discontinuous variations at 2.5 GPa, which revealed a strong redistribution of the electronic charge density and considerably changed interactions among bonding atoms. Thus, the IPT is originated from the considerable variation in the electronic charge density. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

ChemInform Abstract: On Squaring Triangles — Structural Motifs in Cu—In—Sb Compounds.

Two new compounds, Cu₇In_2.5Sb_0.5 (I) and Cu₂In_0.75Sb_0.25 (II) are prepared from the elements (silica ampules, 1173 K, 3 d, followed by annealing at 573—773 K for 220 d).     

Nonplanar dust ion-acoustic solitary and shock waves in a dusty plasma with electrons following a vortex-like distribution

Properties of nonplanar (viz. cylindrical and spherical) dust ion-acoustic (DIA) solitary and shock waves propagating in a dusty plasma containing charge fluctuating stationary dust, inertial warm ions, and non-isothermal electrons following a vortex-like distribution, are investigated by the reductive perturbation method. It has been shown that all the basic features of the DIA solitary and shock waves are significantly modified by the effects of vortex-like electron distribution, dust charge fluctuation, and nonplanar cylindrical and spherical geometries. The implications of our results in some space and laboratory dusty plasma environments are briefly discussed.     

Analysis of the supramolecular structures of Sb(III) and Sb(V) catecholate complexes from the viewpoint of ligand solid angles

The ligand solid angle approach has been successfully applied to the analysis of the catecholate complexes of Sb(III) and Sb(V). The Sb(III) complexes possess an electron lone pair that influences their molecular structure but does not behave as a classic “ligand” when intermolecular interactions are concerned. The Sb(III) complexes in solid state form numerous intermolecular interactions that effectively increase metal shielding, and herein we analyze the effects of the lone pair of electrons on the complex coordination geometry. In the five-coordinate R₃CatSb(V) complexes (Cat = catecholate ligand, R = Ph, Me, Cl) the metal is shielded by 87(3)% and multiple intermolecular contacts are observed. The central metal in the six-coordinate antimony(V) complexes R₃CatSb(V) · L is shielded to the extent of 89(2)% and no strong attractive intermolecular interactions are detected in solid state. Thus, the metal shielding in excess of 85% is required to prevent complex dimerization or additional ligation of the central atom by a nucleophile.