Preparation and characterization of AgI nanoparticles with controlled size,morphology and crystal structure

AgI nanoparticles were prepared by solution-based routes using water-soluble anionic or cationic polyelectrolytes as capping agents. Depending on the polyelectrolytes, AgI nanoparticles with well-defined morphology, size, and phase compositions were obtained: the use of poly(sodium 4-styrenesulfonate) (PSS) resulted in AgI nano-rods of β-AgI in wurtzite structure (2H); with poly(acrylic acid sodium salt) (PAS) truncated-tetrahedron shaped γ-AgI nanoparticles (nanotetrahedra) in zinc-blende structure (3C) were obtained; by employing poly(diallyldimethylammonium chloride) (PDADMAC) plate-like AgI nanoparticles (nano-plates) consisting of unusual polytype phases of AgI (7H and 9R) were formed. Macroscopically unstable γ-AgI and 7H and 9R phases could be stabilized in the form of nanocrystalline powders. They transform reversibly into the high temperature α-AgI phase and exhibit unusually high ionic conductivity and substantially smaller transformation enthalpy values compared to the macroscopic β-AgI.     

Global exponential stability for nonautonomous cellular neural networks with delays

In this Letter, by utilizing Lyapunov functional method and Halanay inequalities, we analyze global exponential stability of nonautonomous cellular neural networks with delay. Several new sufficient conditions ensuring global exponential stability of the network are obtained. The results given here extend and improve the earlier publications. An example is given to demonstrate the effectiveness of the obtained results.     

不等式约束优化问题的一个势函数

基于Carroll(1961)建立的罚函数，本文给出了不等式约束优化问题的一个势函数，并且讨论了该函数的性质．最后证明了在此基础上建立的对偶算法具有Q-线性收敛性．     

AnUV-algorithm for semi-infinite multiobjective programming

In this paper, we give an application ofUV-decomposition method of convex programming to multiobjective programming, and offer a new algorithm for solving semi-infinite multiobjective programming. Finally, the superlinear convergence of the algorithm is proved.     

基于特征分裂有限元准隐格式的共轭传热整体耦合数值模拟方法

共轭传热现象在科学和工程领域中大量存在.随着计算能力的发展,对共轭传热现象进行准确有效的数值模拟,成为科学研究和工程设计上的重要挑战.共轭传热数值模拟的方法可以分为两大类:分区耦合和整体耦合.本文采用有限元法对共轭传热问题进行整体耦合模拟.固体传热求解采用标准的伽辽金有限元方法.流动求解采用基于特征分裂的有限元方法.该...     

Sufficient Conditions for Amalgamated 3-Manifolds to be ∂-Irreducible∗

In this paper, the authors give some sufficient conditions for an amalgamated 3-manifold along a compact connected surface F with boundary to be ?-irreducible in terms of distances between some kinds of vertex subsets of the curve complex and the arc complex of F.     

Deoxygenation of epoxides by fluorenylidene

Irradiation of 9-diazofluorene in the presence of epoxides yields fluorenone and an equimolar concentration of the alkene formed from the stereospecific deoxygenation of the epoxide.     

钙钛矿型氧化物负载纳米金属催化剂结构的动态调变及其催化氧化CO反应性能

研究了钛酸钡和钛酸钙担载的Ag和Pt纳米催化剂的表面结构随氧化-还原处理过程的动态变化及其对CO完全氧化反应性能的影响.发现氧化物担载的Ag催化剂在氧化处理后其催化活性较还原处理的高; X射线衍射(XRD)和X射线光电子能谱(XPS)表征结果表明,氧化处理能够提高载体表面Ag颗粒的分散度,而还原处理导致Ag颗粒的聚集,从而降低了催化氧化CO反应的活性.氧化-还原处理改变了担载Ag纳米粒子的尺寸并影响其CO氧化反应活性.与此相反,氧化物担载的Pt催化剂在还原处理后所表现出的CO氧化反应活性较氧化处理的高; 对比研究发现,氧化和还原处理后Pt纳米粒子的尺寸基本相同,但是氧化处理的样品中Pt表面物种以氧化态为主,而还原处理后Pt表面物种主要为金属态.Pt纳米粒子表面化学状态随氧化-还原处理的调变是导致表面催化活性差异的主要原因.