KRISTALLSTRUKTUR VON BIS(DIETHYLDITHIOCARBAMATO)-PHENYLPHOSPHAN UND SYNTHESE EINIGER MONO- UND BIS(DIORGANYLDITHIOCARBAMATO)PHOSPHANE

Abstract

By reaction of organylchlorophosphanes with sodium dithiocarbamates compounds of the type RP(S₂CNR₂′)₂ with R = CH₃, C₆H₅; R' = CH₃, C₂H₅, CH(CH₃)₂, C₆H₅ and of the type (C₆H₅)₂PS₂CNR₂′ with R' = CH₃, CH(CH₃)₂ as well as compound [(C₆H₅)₂PS₂CN(CH₃)CH₂-]₂ are obtained. The crystal structure of C₆H₅P(S₂CN(C₂H₅)₂)₂ shows that the trend from bidentate to monodentate bonding of the dithiocarbamate ligands in the homologous series RE(S₂CN(C₂H₅)₂)₂; E = Bi, Sb, As, P is continued for E = P.

Durch Umsetzung der jeweiligen Chlorophosphane mit den entsprechenden Natriumdithiocarbamaten können folgende Verbindungen erhalten werden: Verbindungen des Typs RP(S₂CNR₂′)₂ mit R = CH₃, C₆H₅; R' = CH₃, C₂H₅, CH(CH₃)₂, C₆H₅; Verbindungen des Typs (C₆H₅)₂PS₂CNR₂′ mit R' = CH₃, CH(CH₃)₂ sowie [(C₆H₅)₂PS₂CN(CH₃)CH₂-]₂. Die Kristallstruktur von C₆H₅P(S₂CN(C₂H₅)₂)₂ zeigt, daß sich der Trend zu schwächer ausgeprägter zweizähniger Bindungsweise der Dithiocarbamatliganden in der homologen Reihe RE(S₂CN(C₂H₅)₂)₂; E = Bi, Sb, As, P für E = P fortsetzt.     

Fabrication of zinc/silver binary nanoparticles,their enhanced microbial and adsorbing properties

Monometallic ZnO nanoparticles were prepared by hydrolysis of zinc acetate with ammonium hydroxide solution. Bimetallic zinc-silver nanoparticles (ZnO-AgNPs) were prepared using metal displacement galvanic cell reaction in presence of cetyltrimethylammonium bromide (CTAB). The optical and photo-physical properties of both NPs were determined. Surface plasmon resonance (SPR) intensity of ZnO-AgNPs depends on the ratio of metal salt precursors and other experimental conditions. The optical band gap (2.98 eV), agglomeration number (26819.92), and molar concentration (1.14 × 10⁻⁴ mol/liter) of ZnO-AgNPs were determined. Langmuir adsorption monolayer, Freundlich, intraparticles diffusion and multilayer adsorption isotherms used for the determination of maximum adsorption efficiency and adsorption isotherm parameters to the removal of safranin dye from an aqueous solution. The kinetics of safranin removal has also been discussed with pseudo-first order, pseudo-second order, intraparticle diffusion and multilayer kinetic models. The antibacterial and antifungal activities of ZnO, Ag and ZnO-AgNPs were determined against human pathogens using growth kinetic and disk diffusion methods. The concentrations of ZnO-AgNPs have significant effect on the bacterial growth kinetics. The death rate constants increase with increasing the NPs concentrations. It has been found that the ZnO-AgNPs hold higher microbial activities than that of monometallic counterpart, ZnO and AgNPs. Mechanism of bacterial growth and death was discussed.     

可压可溶两相驱动问题的迎风混合元方法

研究迎风混合元方法求解多孔介质中含弥散的可压缩可混溶两相渗流驱动问题, 利用变分形式和先验估计的理论技巧,得到饱和度近似的L²模和压力近似的H¹模最优阶误差估计,数值实验证实该方法在克服数值扩散和非物理振荡方面是很有效的.     

单空位体系多尺度模拟

基于多尺度协同算法，实行了统一动力学模拟方案，研究了单空位体系的位移分布与位移振荡行为、能量随时间起伏以及差分电荷密度与外部环境的影响.计算结果发现位移分布及其相关行为反映了单空位体系的量子力学效应；同时，体系总能、差分电荷密度计算则给出了外部环境的影响，反映了经典效应与量子效应的耦合. 关键词： 多尺度杂化算法 统一动力学 电子态 原子位移     

Lateral thermoconcentration convection in weakly stratified liquids

The dynamics of relaxation and transformation of the structure of convective flows of a weakly stratified liquid are investigated by optical methods in the case of uniform lateral heating. The experiments were carried out for different (small (S = 0.22%) and high (6.5%) basic-salinity values, for which the main parameters of the medium (the thermal expansion coefficient, the saline compression coefficient, the kinematic viscosity, the thermal diffusivity, and the salt diffusion coefficient) differ somewhat. It is shown that the dependence of the structure parameters on the properties of the medium is weak, which justifies the possibility of extrapolating the data of bench experiments on highly stratified liquids to weakly stratified natural systems, such as the atmosphere and the hydrosphere. It is shown that, over a wide range of the experimental parameters, the length and height of the convective cells vary at a constant rate.     

电介质中的电位移

从热力学角度分析了电位移的明确意义，得到了电位移Ｄ的算符表达式，分析了电位移的多极展开中的唯一性。     

Measurement of 3-D displacement of cambered mirror of cryogenic optical system using white light speckle method

We report a method measuring 3-D displacement of cambered mirror for cryogenic optical system using white light speckle photography with double light sources and double cameras. Data acquiring and processing based on a digital image processing system is described. The 3-D displacement and displacement vector distributions in two low-temperature ranges are measured.     

An implicit Lagrangian lattice Boltzmann method for the compressible flows

In this paper, we propose a new Lagrangian lattice Boltzmann method (LBM) for simulating the compressible flows. The new scheme simulates fluid flows based on the displacement distribution functions. The compressible flows, such as shock waves and contact discontinuities are modelled by using Lagrangian LBM. In this model, we select the element in the Lagrangian coordinate to satisfy the basic fluid laws. This model is a simpler version than the corresponding Eulerian coordinates, because the convection term of the Euler equations disappears. The numerical simulations conform to classical results. Copyright © 2006 John Wiley & Sons, Ltd.     

Front propagation for discrete periodic monostable equations

This paper deals with front propagation for discrete periodic monostable equations. We show that there is a minimal wave speed such that a pulsating traveling front solution exists if and only if the wave speed is above this minimal speed. Moreover, in comparing with the continuous case, we prove the convergence of discretized minimal wave speeds to the continuous minimal wave speed.     

A note on the solution of not balanced banded Toeplitz systems

A direct algorithm is presented for the solution of linear systems having banded Toeplitz coefficient matrix with unbalanced bandwidths. It is derived from the cyclic reduction algorithm, it makes use of techniques based on the displacement rank and it relies on the Morrison–Sherman–Woodbury formula. The algorithm always equals and sometimes outperforms the already known direct ones in terms of asymptotic computational cost. The case where the coefficient matrix is a block banded block Toeplitz matrix in block Hessenberg form is analyzed as well. The algorithm is numerically stable if applied to M‐matrices that are point diagonally dominant by columns. Copyright © 2007 John Wiley & Sons, Ltd.