玻璃纤维增强复合材料的损伤分析

本文对玻璃纤维增强复合材料层合板进行了拉、剪多向应力本构关系的实验研究,成功地用软x射线照相观察到材料内部微裂纹沿纤维方向近似均匀分布,并沿裂纹面扩展至破坏的损伤形貌,同时结合声发射技术等监测其扩展规律。在此基础上建立了基于微观机制的微裂纹损伤模型,预测材料的损伤非线性本构关系和破坏,以及实验观察到的一些复合材料特有的损伤现象,理论预测结果与实验值吻合。     

双基地中两坐标收站的三维定位跟踪算法

文中讨论了Ｔ／Ｒ—Ｒ型双基地系统中无俯仰信息收站对运动目标的三维定位跟踪能力;通过若干观测点上测量数据的组合,较好地实现厂对运动目标的三维定位跟踪,从而可以将目标的高度信息从变化的距离和之差的测最值中提取出来。文中以仿真手段证明了这种方法的可行性。     

高含钛量碳化硅纤维的研制

本文采用一种聚钛硅氧烷与聚碳硅烷反应,制得了Ti/Si摩尔比为0.10的聚钛碳硅烷。该聚合物具有良好的成丝性与稳定性,经熔融纺丝,再经不熔化处理后,在氮气气氛保护下1300℃热处理后制得了高含钛量的碳化硅纤维。文中对聚钛硅氧烷的合成与结构,它与聚碳硅烷的反应过程及聚钛碳硅烷的热分解特性进行了分析与研究。     

微型计算机在复合材料强度准则研究中的应用

文中论述了运用微型计算机(IBM-PC)进行复合材料强度准则研究的方法,包括强度包络线绘制、双向加载数据采集及实验数据处理等,同时还研究了如何确定双向试验中的破坏载荷值,并在分析实例中提供了较详细的数据。     

连续碳化硅纤维的研制

本文研究了用先驱体法制备连续碳化硅(SiC)纤维的全过程。通过常压高温裂解法制得纺丝性能好的聚碳硅烷,经100孔熔融纺丝、不熔化处理和高温烧成等一系列工艺处理,制得了高性能的SiC纤维。该纤维单丝直径8～15微米,连续长度达100米,抗拉强度为2～2.3GPa,抗拉模量178GPa。主要性能达到日本同类产品八十年代的水平。本文还对制备工艺的一些基本规律及连续纤维的主要性能进行了研究。     

抗超高速撞击多层结构复合材料研究

本文介绍了抗超高速撞击多层结构复合材料的设计、制备和实验,并对结果进行了讨论,实验证明,以SiC陶瓷基复合材料为防护层、以空心微珠或多孔变密度复合材料为缓冲层、以编织物复合材料为结构层的多层结构复合材料,具有面密度低、抗撞击速度范围宽、抗撞击性能好的特点。     

Bureaucracy Does Its Thing: US Performance and the Institutional Dimension of Strategy in Afghanistan

It is not too soon to draw cautionary lessons from the inconclusive results of US performance during more than 11 years of Operation ‘Enduring Freedom’ in Afghanistan. As in Vietnam, fundamental difficulties persist in adapting enduring institutions to the requirements of strategy. At the heart of the matter is tension between the assumptions that underlie counterinsurgency as practiced in Afghanistan and organization of the US Armed Forces, State Department, and Agency for International Development. Knowledge of basic principles and necessary changes is available to answer the question, could the US have done better?     

Global counterinsurgency and US army expansion: the case for recruiting foreign troops

Given the nature of global counterinsurgency operations, the demands of military expansion, and the need for cultural, linguistic, and regional expertise, the United States Army should evaluate the establishment of US-led foreign troop units for its evolving force structure. This article proposes the creation of an American foreign legion based upon the recruitment of US-led, ethnically homogeneous tribal force units to meet the grist mill of counterinsurgency operations. This structured approach would be more beneficial than the current reliance on a de facto American Foreign Legion, represented by private military contractors (PMCs), many of them comprised of foreigners. These PMCs carry a number of oversight, accountability, and legal risks not found in a fully integrated, and US-officered foreign legion. The British Brigade of Gurkhas, the South-West African Police Counter-Insurgency Unit (Koevoet), and the Kit Carson Scouts serve as relevant historical examples where foreign troops were used to supplement national manpower resources.     

Counterinsurgency force ratio: strategic utility or nominal necessity

As a consequence of intervention in Iraq and Afghanistan, force ratio for counterinsurgency (COIN) has come under increased scrutiny. Reduced to its essence, the issue is simply, ‘How many troops does it take to get the job done?’ This answer has been sought by the US military, academia, and think tanks. There have been numerous responses, culminating in several ‘plug-and-play’ equations for minimum force ratios in COIN operations. Due to the impossibility of determining precisely how many insurgent forces there are, it has become common to base force ratios on the population of the country. In the realm of policy, the question above is posed as, ‘How many of our troops does it take to get the job done?’     

基于插件技术的人工免疫智能空间优化平台研究

采用人工智能方法求解空间优化问题已成为当前地理学研究领域的热点之一。研究目的在于通过设计一个开放的、可扩展的人工免疫空间优化模型框架,开发基于插件技术的优化工具软件,丰富空间优化决策支持的方法和技术体系。研究从空间优化问题的基本特点和计算需求出发,定义了面向空间优化问题求解的克隆选择优化模型框架。在此基础上,采用"插件-宿主平台"结构设计了人工免疫智能空间优化平台的总体架构,定义免疫算子插件与空间优化问题应用插件开发机制。实验结果表明,平台的架构和功能设计充分考虑了计算平台的开放性和扩展性,通过平台标准接口的功能扩展可实现对不同类型空间优化问题的求解。空间优化问题研究者或政府决策部门无需关系人工免疫优化方法的具体内涵即可基于本平台完成其具体空间优化决策支持任务。