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671.
石墨烯热导率远高于传统金属薄膜等导热材料,可用作热扩散材料。石墨烯纸由石墨烯微片组装而成,石墨烯微片尺寸大小对其组装方式微观结构以及宏观导热性能等具有重要影响。采用溶液过滤自组装方法制备了分散均匀的氧化石墨烯纸,然后在Ar/H2气氛下对氧化石墨烯纸进行热还原处理,得到了石墨烯纸。结果表明,大尺寸石墨烯微片组成的石墨烯纸结构更加致密、结晶度更高;0.5μm~3μm和50μm~100μm的氧化石墨烯所制备的石墨烯纸的热导率分别为632.8 W/m K和683.7 W/m K,大尺寸石墨烯微片组成的石墨烯纸热导率提高了8%。 相似文献
672.
Ulrich Hendel 《Defence and Peace Economics》2016,27(5):665-687
This paper examines the interaction between a growth-oriented terrorist organization and an uninformed government based on a two-period signalling game. Combining the signalling game and organizational growth approaches of previous contributions, this paper shows that, if a terrorist group follows a growth strategy, it has an incentive to appear weaker than it is by mimicking the behaviour of a smaller organization. Depending on its beliefs about the extent of the terrorist threat, it can be optimal for a government to spend more on second-period counter-terrorism measures if it is not attacked in the first period than if it were attacked. 相似文献
673.
Michael E. Smith 《Contemporary Security Policy》2016,37(3):446-460
The EU Global Strategy (EUGS) is a broad and ambitious document in terms of its geographic scope and thematic priorities. However, the EU cannot devote equal attention to all aspects of the EUGS; so there is still scope for more clarity regarding the EU’s core strategic aims. This article argues that in addition to fostering internal cohesion, the EU’s strategic priority must involve stabilizing its own neighbourhood. This task has challenged the EU for decades because of an inherent credibility deficit regarding the EU’s own capabilities, yet the EUGS does not diagnose and remedy this problem as effectively as it could have. Therefore much more work will need to be done in terms of reforming EU institutions and developing common capabilities if the EU hopes to achieve its central internal and external security goals as outlined in the EUGS and related policy statements. 相似文献
674.
Hylke Dijkstra 《Contemporary Security Policy》2016,37(3):369-373
EU High Representative Federica Mogherini presented her EU Global Strategy (EUGS) in June 2016. Encircled by security crises, it is difficult to think of something more important for Europe than collective action with the aim of weathering the storm. The EUGS, in this respect, seeks to define common ends and identify means. So what do we make of the EUGS? What does the EUGS tell us about the current role of the EU in global affairs? And how will the withdrawal of the UK from the EU affect foreign and security policy? As a way of introduction to the forum, this article notes that the EUGS focuses on the neighbourhood, puts the interests of European citizens first, identifies civilian means, and has created momentum on security policy. The key question, however, remains whether there is any interest in the EUGS beyond the foreign policy elites. 相似文献
675.
如今大规模地理数据正在社会各个部门和组织中迅速积累,但是由于部门利益和历史沿袭等原因,大规模地理数据共享仍然极具挑战,相应共享技术需求仍然极其旺盛。作为地理数据共享的基础方式之一,传统单机地理数据格式转换技术,一方面受限于磁盘读写及带宽瓶颈,另一方面面对日趋庞大的数据规模,已很难满足实际应用需求。因此提出一种针对栅格地理数据的并行格式转换引擎,采用高性能计算集群环境支持大规模栅格地理数据转换共享,大幅降低了大规模栅格地理数据转换过程的时间成本。栅格地理数据并行格式转换引擎采用基于公共接口的设计理念,框架灵活、具有良好的扩展性,支持地理数据格式的读写自定义以及新数据格式添加,能够实现接入数据格式间的任意两两转换。为验证引擎框架及其处理效率,在Lustre并行集群环境下以格网数据交换格式(国家地理空间数据交换格式)向常见栅格地理格式的转换为示例进行了测试实验。结果表明,栅格地理数据并行格式转换引擎能够在8个节点Lustre集群中达到7.54的良好并行加速比。 相似文献
676.
火炮初速量测是火炮进行弹道准备中的一项重要内容,运用灰色理论探讨火炮初速预测问题,既有利于提高火炮射击精度的修正,又有利于进一步完善火炮初速测量雷达的使用操作和改进设计。针对火炮初速随机变化的特点,基于灰色理论中的GM(1,1)模型,构建火炮初速灰预测模型,确定预测结果精度检验方法。最后通过一应用实例验证了该方法具有一定的合理性与实用性。 相似文献
677.
利用集群搜索对策的理论与方法 ,建立了集群对固定目标的一类搜索对策模型 ,给出了集群的ε -最优搜寻策略 ,并考虑了其在搜索过程中的应用 相似文献
678.
针对现代非接触战争的特点,用数学方法研究导弹对抗模型问题,针对作战的不同目的和要求,建立两个导弹对抗的非线性规划数学模型,对模型求解设计了近似方法,该方法把上述非线性规划模型化为多个线性规划模型进行求解.对一类较简单的特殊情况进行了仔细分析,得到了分析解.最后指出该方法如何应用于动态实时优化决策.本文的方法可用来预测和评估导弹对抗的效果,为作战实时优化决策提供参考. 相似文献
679.
680.
The Selection Allocation Problem (SAP) is a single period decision problem which involves selecting profit‐maximizing (or cost‐minimizing) activities from various distinct groups, and determining the volume of those activities. The activities in each group are selected subject to the availability of that group's resource, which is provided by either pooling or blending raw inputs from several potential sources. Imbedded in the decision process is the additional task of determining how much raw input is to be allocated to each group to form the resource for that group. Instances of this problem can be found in many different areas, such as in tool selection for flexible manufacturing systems, facility location, and funding for social services. Our goal in this paper is to identify and exploit special structures in the (SAP) and use those structures to develop an efficient solution procedure. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 707–725, 1999 相似文献