论企业竞争中的先动优势、风险态度和预期收益

运用博弈论的基本理论，根据企业决策中的行动先后所产生的收益差别，说明了市场竞争中先行动者的收益优势，以及拥有信息较多者收益未必高的道理；通过利益分配中的讨价还价模型，分别就风险偏好、风险中性和风险规避等三种类型企业，分析了常和博弈中的风险态度和预期收益之间的关系，得出了二者正相关的结论，最后指出，市场信息获取固然重要，但更重要的是尽快付诸行动，同时在行动中勇于承担风险，这样才能获得理想的收益。     

A Tractable Class of Maximal Hedging Policies in Multi-Part Manufacturing Systems

The flow control problem in multi-part failure prone manufacturing systems is considered. While computationnaly attractive, the near optimal controllers of Caramanis and Sharifnia, suffer from the drawback that the production capacity set must be approximated via a very restricted set of inscribed hypercubes, namely those for which a componentwise feasibility requirement is satisfied. Also, due to the completely decoupled nature of production along each component, utilization of the restricted capacity set is suboptimal. A class of capacity set incribed hypercube policies called simple maximal hedging (SMH) policies is introduced. In SMH policies production levels along the various components of the capacity set are coupled, the componentwise feasibility requirement is lifted, and there is no underutilization of production capacity if needed. In a p part types manufacturing system, for partwise additive cost functionals, it is shown that performance evaluation of a given SMH policy reduces to the analysis of p decoupled (fictitious) semi-Markovian machines. The machines are Markovianized via first passage-time analysis and a Padé approximants technique. Numerical optimization over the class of SMH policies in a sample manufacturing system indicates that their performance can come close to that of the optimal control.     

Two simple and efficient displacement‐based quadrilateral elements for the analysis of composite laminated plates

Two simple 4‐node 20‐DOF and 4‐node 24‐DOF displacement‐based quadrilateral elements named RDKQ‐L20 and RDKQ‐L24 are developed in this paper based on the first‐order shear deformation theory (FSDT) for linear analysis of thin to moderately thick laminates. The deflection and rotation functions of the element sides are obtained from Timoshenko's laminated composite beam functions. Linear displacement interpolation functions of the standard 4‐node quadrilateral isoparametric plane element and displacement functions of a quadrilateral plane element with drilling degrees of freedom are taken as in‐plane displacements of the proposed elements RDKQ‐L20 and RDKQ‐L24, respectively. Due to the application of Timoshenko's laminated composite beam functions, convergence can be ensured theoretically for very thin laminates. The elements are simple in formulation, and shear‐locking free for extremely thin laminates even with full integration. A hybrid‐enhanced procedure is employed to improve the accuracy of stress analysis, especially for transverse shear stresses. Numerical tests show that the new elements are convergent, not sensitive to mesh distortion, accurate and efficient for analysis of thin to moderately thick laminates. Copyright © 2004 John Wiley & Sons, Ltd.     

浅谈高压变电站综合自动化系统中的内部通讯网

介绍和比较LonWorks现场总线网和嵌入式以太网两种站内通讯网方案,它们分别适用于高、中、低压变电站综合自动化系统和超高压变电站综合自动化系统。并就嵌入式以太网在变电站综合自动化系统中应用的一些大家普遍关心的问题予以讨论和说明。     

关于"三要素"的重新认识

求解一阶电路的三要素法似乎是很熟悉的课题。但是对它的认识是否到位、文字的表达是否严谨还需要进一步探讨,对三要素求解方法进行了分析和证明。     

英汉缩略语词汇化手段之我见

英汉缩略语的词汇化现象已广为学术界关注,然百家争鸣,莫衷一是。英汉缩略语必然引发词汇化英汉缩略语的词汇化是一个蕴含玄理的过程。本文认为英汉缩略语的词汇化具有鲜明的人文手段,可概分为缩合法和节略法。汉语的缩略语体现了表义性与取首性;英语的缩略语体现了表音性和任意性。     

ZnS和MgS的高压相变和弹性性质

为了进一步研究ZnS和MgS晶体在高压下的B1和B3结构的晶体结构和弹性性质,利用第一性原理平面波赝势密度泛函理论并通过GGA近似,计算得到了高压下ZnS和MgS晶体B3到B1结构相变的相变压强和高压下的弹性系数（C11,C12,C44,B）,结果发现两者相变压强是11.87和0.78GPa,两者在不同结构的弹性系数（C11,C12,C44）与压强变化具有相同的趋势：C11>C12>C44;同时计算得到了两种物质在基态的结构常数,并将其与其他实验和理论计算的结果对比,发现符合得甚好.     

一种简单Hamilton系统的叉形分岔

利用Hamilton正则方程建立了由1个刚体、3个支座和2根弹簧组成的简单Hamil—ton系统的数学模型,并讨论了系统的实际结构与数学模型之间的差异;利用Lyapunov第一近似理论分析了系统的平衡态的稳定性,研究了系统的分岔．研究结果表明,刚体的转角受到支座、弹簧的3种限制：当弹簧刚度、自然长度、刚体重量和刚体中心与中间支座的距离满足一定条件时,系统只有1个平衡态,而且平衡态是稳定的;当弹簧刚度、自然长度、刚体重量和刚体中心与中间支座的距离不满足这一条件时,原来的平衡态变为鞍点而失去稳定性,同时分支出2个对称的平衡态,并且这2个平衡态是稳定的;系统发生叉形分岔．     

Tennant法计算标准的修正及其应用

为了使Tennant法更适合计算南水北调西线河道内生态需水量,对其计算标准进行了修正.采用实地调查的方法,发现南水北调西线一期工程调水区气温较低,引水河流中鱼类洄游及水生生物的活动期主要集中在7~8月份,而且每年的12月到翌年3月河道均处于冰冻期,所以将Tennant法的用水期修正为7~8月,并将修正后的Tennant法应用于南水北调西线调水区引水枢纽下游的朱倭、朱巴、绰斯甲和足木足4站河道内生态需水量的计算.结果表明修正后的Tennant法计算的生态需水量约占多年平均的25%,可见Ten-nant法对栖息地描述的是否准确直接影响到计算结果.