A comparison of optimization theories for energy conservation in heat exchanger groups

In general,thermal processes can be classified into two categories: heat-work conversion processes and heat transfer processes. Correspondingly,the optimization of thermal processes has to have two different criteria:the well known entropy generation minimization method and the recently proposed entransy dissipation maximization method. This study analyzes the thermal issues in a heat exchanger group,and optimizes the unit arrangements under different constraints based on a suitable optimization crite-rion. The result indicates that the principle of minimum entropy generation rate is valid for optimizing heat exchangers in a ther-modynamic cycle with given boundary temperatures. In contrast,the entransy dissipation maximization is more suitable in heat exchanger optimizations involving only heat transfer processes. Furthermore,the entropy generation rate induced by dumping used streams into ambient surroundings has to be taken into account,except for that originating from the hot and cold-ends of heat exchangers,when using the entropy generation minimization to optimize heat exchangers undergoing a thermodynamic cycle.     

Sufficient and necessary conditions of separability for bipartite pure states in infinite-dimensional systems

The PHC criterion and the realignment criterion for pure states in infinite-dimensional bipartite quantum systems are given. Furthermore, several equivalent conditions for pure states to be separable are generalized to infinite-dimensional systems.     

中小学建筑抗震设计若干问题

本文在青海玉树地震震害经验总结的基础上,对中小学建筑的抗震设防标准、结构体系及常用的砌体结构和框架结构类型存在的问题进行了深入的讨论,从结构体系、抗震措施及施工质量等方面提出了应注意的问题.并对新建中小学建筑的抗震设计提出了建议.     

中国蒙医整骨术骨折分型两种判据及其因果关系

目的:研究中国蒙医整骨术的骨折分型两种判据及其因果关系.方法:基于中国蒙医整骨术对骨折类型的10种分类及其大量临床应用实践,用现代生物力学原理及方法分析验证骨折类型线性与力性分类的科学合理性及其因果关系.结果:中国蒙医整骨术的骨折分型线性判据与力性判据,二者互为因果、完美统一.结论:中国蒙医整骨术骨折分型两种判据是骨折及其类型诊断的根本依据.     

斜阳照文心 灵动写人生—读张蕾教授的《斜阳居杂缀（上卷）》

从自身人生体验入题，对张蕾教授的《斜阳居杂缀（上卷）》进行了解读与评论，凸显了人格魅力，从而提出了：对自己，要“独善其身，人品第一”；对别人，要“相善其群，以人为本”；写文章，要“文善致远，人格至上”。如此“人”向“善”、“群”主“和”、“文”从“心”的回归与升华，必将闪射永恒的光辉。     

正态分布随机参数的一种估计方法

本文提出了一种最大似然估计方法,可对一般非线性模型中服从正态分布的随机参数的均值、协方差矩阵及其在各观测时刻的取值进行合理的估计。     

总熵判据的作用和局限

首先讨论了环境熵变和热源熵变间的区别，以及两者相同时的条件；然后阐述了总熵判据和克劳修斯不等式在本质上并无不同之处，都可以用于判别过程的可逆性；最后将总熵变与隔离体系的熵变相比较，对它们的用途进行了详细讨论。     

逐段线性加载面等向强化时角点处塑性应力应变关系

特雷斯卡屈服条件在等向强化时的强化函数在文献中讨论较少，本文建议了一个强化函数，它能与特雷斯卡屈服函数相匹配，且有效充分的实验基础。它与夸脱理论相结合，得到了在角点处的塑性增量应力应变关系，在角点上剪应力增量与剪应变增量间是单值确定的。