界面热阻对金刚石/银复合材料导热率的影响

研究了金刚石／银复合材料的导热率与金刚石的含量、粒度等之间的关系,着重讨论了界面热阻对复合材料导热率的影响。并阐述了金刚石表面镀钛,能有效改善金刚石对银的润湿性,降低界面热阻,从而提高金刚石／银复合材料的导热率。     

f 壳层耦合态的完全分类与准旋标量算符本征值

本文用二次量子化方法,对l壳层引进准旋、自旋、轨道为(1/2,1/2,l)阶不可约张量的产生-湮灭算符b_(qsm)~(1/2 1/2 t),由4个这种算符按下式耦合成准旋、自旋、轨道标量算符, (?)Y (K_1,k_2,k_3) 与准旋、自旋、轨道算符对易,可用于对耦合态进一步分类。利用Y(k_1,k_2,k_3)与准旋、自旋、轨道算符的适当结合,本文给出了对f壳层完全分类的算符(组),给出了与G.Racah对f壳层分类一致的算符组。     

坚持用中国特色社会主义理论体系武装官兵

坚持用中国特色社会主义理论体系武装官兵、不断夯实守边固防的思想根基.要筑牢高举旗帜、听党指挥这个根本;要着力端正官兵的价值追求;要不断强化官兵守边强边的使命意识.     

An economic sequential screening procedure for limited failure populations

An economic sequential screening procedure is considered for limited failure populations in which defective items fail soon after they are put in operation and nondefective ones never fail during the technical life of the items. A cost model is constructed that involves screening test cost and external failure cost. A sequential scheme that minimizes the expected cost is derived from the solution of a dynamic programming formulation and the optimal decision at each stage is obtained in a closed form. © 1994 John Wiley & Sons, Inc.     

简析蒋介石围追堵截红军长征失败的内因

蒋介石围追堵截红军长征失败的内因主要有:“攘外必先安内”的反动政策导致了蒋介石政治上的孤立;在围追堵截红军长征经过的十几个省份,蒋介石执行了许多与民为敌的政策,直接激起了沿途各省民众的反抗;蒋介石排除异己,欲借红军之力消灭沿途各省地方军阀的“一箭双雕”的部署,使国民党军队内耗严重,贻误了战机;蒋介石非常轻视红军的作战能力,在战略战术方面又显得因循、呆板;此外,国民党军队士气低落,缺乏战斗力也是围追堵截失败的又一原因。     

直升机攻潜过程中投雷点的选择

提出一种优化直升机投雷点的方法,其中考虑了小型反潜鱼雷航程短的特点,以及鱼雷与目标相对方位的变化对鱼雷自导作用距离的影响。最终给出一组优化的数学程序。它可为直升机攻潜过程中投雷点的选择提供一条科学决策的途径。     

Optimum simple step-stress accelerated life tests for weibull distribution and type I censoring

This article presents an optimum simple step-stress accelerated life test for the Weibull distribution under Type I censoring. It is assumed that a log-linear relationship exists between the Weibull scale parameter and the (possibly transformed) stress and that a certain cumulative exposure model for the effect of changing stress holds. The optimum plan—low stress and stress change time—is obtained, which minimizes the asymptotic variance of the maximum likelihood estimator of a stated percentile at design stress. For selected values of the design parameters, nomographs useful for finding the optimum plan are given, and the effects of errors in preestimates of the parameters are investigated. As an alternative to the simple step-stress test, a three-level compromise plan is proposed, and its performance is studied and compared with that of the optimum simple step-stress test. © 1993 John Wiley & Sons. Inc.     

美国海军“大白色舰队”的环球航行

1907年11月16日,是美国海军史上具有重要意义的一天.这天,美国海军最先进的16艘战列舰全部漆成华丽的银白色,整齐地排列在切萨皮克军港,正准备开始美国历史上首次大编队环球航行.     

项目管理模式下的装备研制合同管理的研究

本文首先明确了装备研制合同项目的概念及其意义,并针对我军装备研制合同管理的现状,提出了基于项目管理模式的装备研制合同管理机构及管理流程。为进一步加强装备研制合同管理,使得装备研制合同得以有效履行提供了可行的方法,对于提高我军装备研制效益具有一定的理论和实践意义。     

Economic screening procedures using a correlated variable with multidecision alternatives

Economic screening procedures using a correlated variable are developed for selecting markets in situations when there are several markets with different profit/ cost structures. It is assumed that the performance variable and the screening variable are jointly normally distributed. Profit models are constructed which involve three profit/cost components: profit from a conforming item, cost from an accepted nonconforming item, and screening inspection cost. Methods of finding the optimal screening procedures are presented and numerical examples are given.