激波对超声速流中横向射流的影响

为了揭示激波对超声速流中横向射流的影响,在超声速流中利用长9mm、坡度为23°的斜坡产生激波。组合利用高速摄影仪和纹影仪拍摄激波入射在气体和液体射流的不同位置,以及相同位置不同喷注压降时的流场纹影和阴影图像。结果表明,激波对气体和液体横向射流的影响基本相同,都表现为入射激波增强了湍流度,扩大了燃料空间发展区域,增强了与主流的混合,激波入射在射流的前部比射流的后部影响大。     

21世纪的红外焦平面阵列技术军用前景

引人注目的红外焦平面阵列技术正在取得飞速进展,日益拓展其新的应用领域。结合器件技术讨论21世纪头10～20年间的红外焦平面阵列技术发展趋势和在军事中的应用前景。     

建构主义教学论与教学模式改革

建构主义学习观强调学习的建构性、社会性和情境性 ,对促进教学方法的变革将有重要意义。文章运用建构教学观辨证分析了传统教学模式 ,综合现代以知识为中心、以学生为中心和行为主义理论等现代教育思想 ,分析了传授———建构教学法、合作、探究学习方法。     

强化军人精神支柱的途径

在新形势下 ,围绕“打得赢、不变质”两个历史性课题 ,强化精神支柱 ,坚定理想信念 ,应努力建设良好的政治环境 ,以正确的思想理论、昂扬的革命精神和严格的组织纪律来教育、激励和约束官兵 ,不断强化军人精神支柱。     

Ordering and controlling the dimensions of strategy

Colin Gray’s dimensions of strategy, built upon the earlier work of Clausewitz and Howard, has theoretical, practical, and pedagogic value for the Strategic Studies community. This paper further develops the theory, arguing that the dimensions can be controlled or managed to improve strategic performance. The dimensions are divided into two categories: “internal” and “external” to the process of strategy. The paper describes the dynamic process by which the internal dimensions, which can be controlled, are used to exert influence over the external dimensions that are beyond the control of the strategist. It is argued that six dimensions hold the key to strategic success: politics and the five dimensions concerned with warfighting. This conclusion validates the Clausewitzian paradigm with its emphasis on policy and battle.     

Experimental study of transient pressure wave in the behind armor blunt trauma induced by different rifle bullets

Pressure wave plays an important role in the occurrence of behind armor blunt trauma (BABT), and ballistic gelatin is widely used as a surrogate of biological tissue in the research of BABT. Comparison of pressure wave in the gelatin behind armor for different rifle bullets is lacking. The aim of this study was to observe dynamic changes in pressure wave induced by ballistic blunt impact on the armored gelatin block and to compare the effects of bullet type on the parameters of the transient pressure wave. The gelatin blocks protected with National Institute of Justice (NIJ) class III bulletproof armor were shot by three types of rifle bullet with the same level of impact energy. The transient pressure signals at five locations were recorded with pressure sensors and three parameters (maximum pressure, maximum pressure impulse, and the duration of the first positive phase) were determined and discussed. The results indicated that the waveform and the twin peak of transient pressure wave were not related to the bullet type. However, the values of pressure wave’s parameters were significantly affected by bullet type. Additionally, the attenuation of pressure amplitude followed the similar law for the three ammunitions. These findings may be helpful to get some insight in the BABT and improve the structure design of bullet.     

Timely exposure of a secret project: Which activities to monitor?

A defender wants to detect as quickly as possible whether some attacker is secretly conducting a project that could harm the defender. Security services, for example, need to expose a terrorist plot in time to prevent it. The attacker, in turn, schedules his activities so as to remain undiscovered as long as possible. One pressing question for the defender is: which of the project's activities to focus intelligence efforts on? We model the situation as a zero‐sum game, establish that a late‐start schedule defines a dominant attacker strategy, and describe a dynamic program that yields a Nash equilibrium for the zero‐sum game. Through an innovative use of cooperative game theory, we measure the harm reduction thanks to each activity's intelligence effort, obtain insight into what makes intelligence effort more effective, and show how to identify opportunities for further harm reduction. We use a detailed example of a nuclear weapons development project to demonstrate how a careful trade‐off between time and ease of detection can reduce the harm significantly.     

kittel型反铁电相变的自由能

根据kittel型反铁电相变对称性的变化 ,选择轴矢量 R作为序参量是合适的。由Landau理论 ,相变温度附近的自由能F就可以写成 R幂级数展开的形式。令 F R=0 ,可得到关于序参量的方程 ,从而获得相变温度与自由能的关系     

军事物流服务商准入标准设置和甄选研究综述

军事物流服务商甄选研究是新军事变革下供应商管理发展的重要方向，是有效完成后勤保障任务、顺利实施作战行动的重要保证。基于此，本文从供应商关系理论和发展、物流服务商指标体系选择以及结合其他方法对物流服务商甄选三个方面对国内外研究现状进行总结概述，对整个军事物流服务商的选择过程加以研究，将其科学客观地运用于军事物流服务商选择的实际操作中，对于加强军事物流服务商需求管理、提高选择质效以及优化工作流程具有重大意义。同时，分析现有研究成果的不足，并对其未来发展前景提出展望，针对性地提出了军事物流服务商初步准入标准以及后续复选的方法，为军事物流服务商选择体系的完善提供参考。     

面内阶跃载荷下薄板弹性动力屈曲差分解

根据薄板微元的动力平衡分析导出薄板动力屈曲控制方程,由屈曲瞬间能量转换率守恒条件得出一个压缩波前屈曲变形的附加约束方程,由此得到求解薄板动力屈曲问题的完备定解条件.以受载边夹支的薄板为倒,利用有限差分法得出了薄板前三阶动力屈曲模态和相应的两个特征参数值,并对比分析了薄板静、动力屈曲的差别.分析表明,薄板动力屈曲过程中产生屈曲动能,比静力屈曲要吸收更多的外部能量.