A High-Order Finite Difference Scheme for 3D Unsteady Convection Diffusion Reaction Equations北大核心CSCD

针对三维非稳态对流扩散反应方程,构造了一种高精度紧致有限差分格式,对空间的离散采用四阶紧致差分方法,对时间的离散采用Taylor级数展开和余项修正技术,所提格式在时间上的精度为二阶、在空间上的精度为四阶。利用Fourier稳定性分析法证明了该格式是无条件稳定的。最后给出数值算例验证了理论结果。     

煤炭企业固定工的地位及现存问题的改进

本文对当前煤炭企业用工制度改革存在的问题、改进途径和各种形式用工的比例进行了分析,并指出为适应煤矿安全生产及机械化发展的需要,保持固定工的用工比例,克服“铁饭碗在手”等隋性意识,充分发挥他们的骨干作用是问题的关键。为此,本文提出了改变工资结构、劳动结构等相应的改革措施。     

电网谐波的微机检测和分析系统

为贯彻水电部《电力系统谐波管理暂行规定》文件,适应电网谐波检测管理的需要,研制了本装置。它在微处理机的基础上实现了对电网谐波的自动检测:能测量基波至19次谐波的电压、电流、相位、有功和无功功率,以及电压和电流的总畸变率。本文简述其工作原理、硬件框图、程序流程图、提高测量准确度的措施、测试结果等。     

煤炭码头船货匹配下泊位动态分配多目标优化模型及算法

本文针对输出型煤炭码头船货匹配下泊位动态分配问题,构建了堆场-取装线-泊位-船舶联合分配优化数学模型,并设计了采用仿真推演策略解码的遗传算法求解。首先,综合考虑船舶、泊位、堆场、取装线、煤种、航道开放时间和装船作业规则等要素,以船舶在港时间最短和作业效率最大为目标建立了相应的多约束多目标优化模型。然后,综合多目标优化、遗传算法以及仿真推演技术,设计了相应的遗传算法求解,包括:组合式编码、采用仿真推演策略的解码方法,追加了具有合法性检查的染色体生成算法,设计了采用多种策略的遗传操作等。最后实例表明,本算法的执行效率高而且优化效果好。     

关于随机变量期望方差的两个注记

文献[1]中给出了有关条件期望与三个随机变量独立的两个充要条件,本文通过几个反例说明其充分性是不成立的.分析了文献[4]中一个定理证明存在的错误,并给出了新的证明.     

Regio- and stereoselectivity in the addition reactions of CH-acids to aldehydes under the conditions of phase-transfer catalysis

The regio- and stereoselectivity of the reactions of carbanions, generated from alkanals, carboxylates of the type XYCHCOOEt (X = EtOOC, CN, Ac; Y = H, Br), or derivatives of 3-methyl-4-phosphono-2-butenoic acid using PTC techniques, with aldehydes of various types (alkanals, ,-enals, cross-conjugated enedials, benzaldehydes,etc.) are reviewed. The factors affecting the outcome of these reactions are discussed. The carbanion analogs, triphenylphosphorus ylides, are shown to attack selectively at one of the aldehyde groups of aromatic dialdehydes. The regularities found for the title reactions were used in the syntheses of some biologically active isoprenoids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1867–1885, October, 1995.     

Carbocyclic and nitrogen-containing fused CH-acids with an annelated indenyl fragment. Thermogravimetric and X-ray structural analysis of 6H-indeno[1,2-b]quinoline

Based on thermogravimetric characteristics first obtained for the model 6H-indeno [1,2-b]quinoline, the scheme of thermal conversions of this compound in the temperature range 20–700 °C has been proposed, and the limit of its thermal stability (300 °C) has been determined. This temperature is recommended as the optimum for synthesizing fused benzoaza(diaza)fluorenes. Based on the results of X-ray structural analysis, the molecules of the studied indenoquinoline form centrosymmetric pairs, which are arranged in (110) layers. The molecules are orientationally disordered. The observed self-association of these molecules is similar to the - association of fused heterocyclic systems with-excessive and ****- deficient fragments. It has been suggested that interferon-inducing and antitumor compounds with an annelated indenyl fragment have a common mechanism of action according to the intercalation model of stacking structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 703–709, April, 1995.     

Wilson's functional equations on groups

We study properties of solutionsf, g, h C(G) of the functional equation

Products and transforms of white-noise functionals (in general setting)

Some sharp results about Weiner and Wick products of whitenoise functionals are obtained. Using the inequality of Wick products we show to what extent scaling transformations, translations, and Sobolev differentiations can be performed on white-noise functionals.This work was supported by the National Natural Science Foundation of China. This paper is an enlargement and revised version of the paper entitled Products and Transforms of White-Noise Functionals (preprint, 1990).