新中国60年国防战略的历史演变

新中国成立60年来,国防战略先后做过4次重大调整.每一次调整既始终贯彻了积极防御这一新中国国防战略的本质要素,又与当时中国国家安全环境以及国家发展战略密切相关,有着明显的时代特征,显示了新中国国防战略的日臻成熟.     

淮海战役亲历记

本文作者在淮海战役中任华东野战军第9纵队第73团(济南第一团)第7连指导员,亲历了淮海战役中的一些重要战斗.在纪念淮海战役60周年之际,作者著文以亲身经历追忆了当年战火硝烟中的一些往事,缅怀了在战场上英勇牺牲的战友,给读者留下了历史的启迪和现实的思考.     

Flexible capacity strategy in an asymmetric oligopoly market with competition and demand uncertainty

This article studies flexible capacity strategy (FCS) under oligopoly competition with uncertain demand. Each firm utilizes either the FCS or inflexible capacity strategy (IFCS). Flexible firms can postpone their productions until observing the actual demand, whereas inflexible firms cannot. We formulate a new asymmetrical oligopoly model for the problem, and obtain capacity and production decisions of the firms at Nash equilibrium. It is interesting to verify that cross‐group competition determines the capacity allocation between the two groups of firms, while intergroup competition determines the market share within each group. Moreover, we show that the two strategies coexist among firms only when cost differentiation is medium. Counterintuitively, flexible firms benefit from increasing production cost when the inflexible competition intensity is sufficiently high. This is because of retreat of inflexible firms, flexibility effect, and the corresponding high price. We identify conditions under which FCS is superior than IFCS. We also demonstrate that flexible firms benefit from increasing demand uncertainty. However, when demand variance is not very large, flexible firms may be disadvantaged. We further investigate the effects of cross‐group and intergroup competition on individual performance of the firms. We show that as flexible competition intensity increases, inflexible firms are mainly affected by the cross‐group competition first and then by the intergroup competition, whereas flexible firms are mainly affected by the intergroup competition. Finally, we examine endogenous flexibility and identify its three drivers: cost parameters, cross‐group competition, and intergroup competition. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 117–138, 2017     

激光PIV流场显示与测量系统

利用课题组自行设计研制的一套粒子图像测速(PIV)系统对高速水洞中流场进行了测试研究.测试系统中,光源使用Nd:YAG调Q双激光器,其波长532 nm,脉冲时间8 ns,脉冲能量100 mJ;示踪粒子则采用直径200 μm的镀银聚苯乙烯微球.无模型空流场测试结果表明,该系统对无模型空流场的测试误差小于1.3％;而通过圆球模型绕流流场测试结果与其理论值的对比发现,大部分测试流场区域的测试误差小于2％.     

Defence expenditures and economic growth: The externality effect

In a series of articles published in the Fall 1990 issue of Defence Economics Alexander (1990), Atesoglu and Mueller (1990) and Huang and Mintz (1990) have all specified and empirically estimated defence‐growth models based on a neoclassical production function. We now isolate the externality component in our model, re‐estimate its coefficients using data on the U.S. economy 1952–88 and compare specifications and results with Atesoglu and Mueller (1990) and Alexander (1990).     

H桥NPC三电平逆变器的输出电压谐波分析

逆变器输出电压的谐波分析为输出滤波器的设计提供了基本的理论依据.针对大容量H桥NPC三电平逆变器,结合PWM技术的基本思想,推导出逆变器中各开关管的开关函数.基于开关函数,得到了输出电压解析表达式,并分析了输出电压的谐波频谱特性.仿真与实验进一步证明了输出电压解析表达式的正确性.该分析方法推导过程简单明了、物理意义清晰...     

半实物火炮随动系统定型试验负载仿真器设计

简述了火炮随动系统在武器系统中的主要用途,并提出了满足火炮随动系统定型试验的半实物负载模拟仿真器的要求,介绍了基于CAN总线的随动系统负载模拟半实物仿真器的系统组成及工作原理,重点分析研究了半实物仿真器设计中涉及的关键技术,包括路谱冲击模型、海浪冲击模型等的建立.     

舰艇通信兵训练效果评估研究

通信兵训练效果的评估结果可以为实际作战能力的提升提供考评的客观依据,有利于训练方法的改进。建立了舰载通信系统作战效能评估指标体系,提出了基于舰载通信系统作战效能的通信兵训练效果评估方法,利用训练前后系统作战效能的提高量化值反映训练效果。以短波通信分系统为例进行仿真,验证了该方法的有效性。对指导通信兵的日常训练、提高其训练效果具有重要意义。     

Optimal control policies for a periodic review inventory system with emergency orders

We describe a periodic review inventory system where emergency orders, which have a shorter supply lead time but are subject to higher ordering cost compared to regular orders, can be placed on a continuous basis. We consider the periodic review system in which the order cycles are relatively long so that they are possibly larger than the supply lead times. Study of such systems is important since they are often found in practice. We assume that the difference between the regular and emergency supply lead times is less than the order-cycle length. We develop a dynamic programming model and derive a stopping rule to end the computation and obtain optimal operation parameters. Computational results are included that support the contention that easily implemented policies can be computed with reasonable effort. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 187–204, 1998     

基于球状模型的短波频率泛克里金重构算法

针对现有短波频率优选方法中数据处理过程复杂、输入参数条件苛刻、工程实现难度较大等不足,结合电离层变化特性,提出了一种基于球状模型的泛克里金法,应用于短波频率的重构。利用短波频率管理系统中大量的实测频率数据,构建了符合频率数据变化特征的基于球状模型的变异函数,建立了反映沿经度、纬度及水平方向通信频率变化剧烈程度的漂移表达式。随机选取多个样本数据,通过交叉重构法对短波频率数据进行重构。实验结果表明,基于球状模型的泛克里金法具有较高的频率重构精度,能够应用于短波通信频率的重构,特别是满足军事通信方面对短波频率优选手段的需求。