Efficient discretization of pressure‐correction equations on non‐orthogonal grids

An alternative discretization of pressure‐correction equations within pressure‐correction schemes for the solution of the incompressible Navier–Stokes equations is introduced, which improves the convergence and robustness properties of such schemes for non‐orthogonal grids. As against standard approaches, where the non‐orthogonal terms usually are just neglected, the approach allows for a simplification of the pressure‐correction equation to correspond to 5‐point or 7‐point computational molecules in two or three dimensions, respectively, but still incorporates the effects of non‐orthogonality. As a result a wide range (including rather high values) of underrelaxation factors can be used, resulting in an increased overall performance of the underlying pressure‐correction schemes. Within this context, a second issue of the paper is the investigation of the accuracy to which the pressure‐correction equation should be solved in each pressure‐correction iteration. The scheme is investigated for standard test cases and, in order to show its applicability to practical flow problems, for a more complex configuration of a micro heat exchanger. Copyright © 2003 John Wiley & Sons, Ltd.     

有消费或投资的华氏宏观经济模型

本文对华罗庚教授的宏观经济模型进行了推广 ,在原来模型的基础上 ,分别增加了消费、投资 ,得到两种不同的模型 ,并对模型具有经济意义的解进行了研究     

具III类功能反应的非自治捕食扩散系统的全局稳定性(英文)

讨论了一类具有扩散率和 III类功能性反应的非自治捕食系统 ,证明了在适当条件下 ,系统是持久的 ,进一步如果系统是周期系统 ,则在一定条件下存在惟一全局稳定的周期解 .     

一类广义Lanchester模型的数值解及若干结论

本讨论了一类广义的Lanchester模型在一些限制条件下的近似解，并给出了若干结论。     

气-固流化床反应器内双流体力学模型及其验证 Ⅱ.单组分两维射流床内流场特性分析

由以质量、动量和能量三大守恒定律为基础的湍流两相流理论出发,建立了描述气固流化床内两相流动的数学模型;在微型计算机上编写了相应的数值计算和图形处理程序;为了验证模型的可靠性,本文着手模拟与分析了单组分颗粒体系两维射流流化床内气、固相速度场、空隙度和压力场随时间、空间变化规律;得到了与前人实验结果相吻合的结论。     

溶液pH值对聚邻甲苯胺电化学性质的影响

本文报道了溶液pH值对聚邻甲本胺电化学性质的影响。研究结果表明,电化学合成的聚邻甲苯胺的循环伏安曲线、氧化电位、膜的颜色、充放电容量、紫外可见光谱以及氧化还原活性都受到溶液pH的影响。在低pH值的溶液中,随着扫描电位的变化,聚邻甲苯胺膜的颜色可逆地变化,而在pH4.13的溶液中进行扫描时,膜的颜色不变化,电化学活性也消失。     

聚电解质溶液中2.6-ANS探针的荧光谱研究

本文合成了2.6—ANS荧光探针分子,并在含有不同外加盐的NaPSS溶液中测定了探针的荧光发射光谱。结果表明:探针的荧光强度随Cs增大而增大,而探针光谱的最大发射波长和半波宽度随Cs增大而减小。当Cs达到一定值时,荧光谱参数与Cs关系曲线出现转折点,此时聚离了链以“类胶束”状态存在。     

Enhanced electrodeposition of indium hexacyanoferrate thin films through improved plating solution stability

An ordinary plating solution for indium hexacyanoferrate (InHCF) thin film deposition, mainly composed of equal concentrations of In³⁺ and [Fe(CN)₆]^3–, usually forms precipitates rapidly when either concentration is higher than few millimolar. This contributes to the plating solution's instability. Moreover, electrodeposited capacities are limited accordingly. In this work, the plating solution's stability and the electrodeposition of InHCF were greatly enhanced by adding a large amount of K⁺ and/or H⁺. It was found that a 10-mM plating solution added with 1 M HCl and 1 M KCl could be stored as fresh over a one-week period, whereas an unmodified plating solution became useless within a couple of minutes. Also, such cationic additions, especially adding H⁺, increased the electrodeposited capacity ca. 18 times at least, as compared with that obtained from the unmodified plating solution. Furthermore, related enhancing mechanisms were proposed and verified. To sum up, this study offers a means for better InHCF electrodeposition and should promote the applications of InHCF films. Electronic Publication     

双甘肽稀土配合物溶液结构的13C和1H NMR研究

~(13)C and ~1H NMR technique was used to study the interaction of Gly-Gly with heavy lanthanide cations Dy~(3+), Ho~(3+), Er~(3+), Tm~(3+) and Yb~(3+) in aqueous solution. The stability constants for the 1:1 and 1:2 complexes of Gly-Gly with Ho~(3+) and Yb~(3+) were determined from the titration curves of chemical shift versus concentration ratio of lanthanide to Gly-Gly. The solution structure of the Ln-Gly-Gly complex was analyzed based upon the ~(13)C and ~1H lanthanide-induced shifts and the results show that in the complex Gly-Gly is coordinated to the lanthanide ion through the carboxyl oxygens with the backbone of the ligand in an extended state.     

Synthesis and characterization of some carbazole-based imine polymers

Five imine polymers, all containing 3,6-disubstituted carbazole ring in the main polymer chain, were synthesized by solution polycondensation of 3,6-diformyl (N-hexyl) carbazole with hydrazine, 1,4-diaminobenzene, 4,4′-diaminobiphenyl, 1,5-diaminonaphthalene and 3,6-(N-hexyl) diaminocarbazole. The polymers were analyzed by spectroscopic methods and compared with two imine models.