一种调节阀式气体炮建模与分析

为研究气体炮各调整参数对其模拟性能的影响 ,笔者利用气体动力学相似理论的有关知识对双活塞调节阀式气体炮进行了数学建模与分析 ,采用四阶龙格—库塔法的思想进行计算 ,并利用MATLAB语言对其进行编程 ,通过在计算机上运行计算程序 ,得出模拟弹丸的加速度—时间模拟曲线。在对模拟曲线特征进行分析的基础上 ,指出了气体炮各调整参数对弹丸加速度—时间曲线的影响。     

机器翻译中语义块汉英变换处理

首先解释了要素句蜕的内涵,同时介绍了HNC理论的句蜕观,并依据HNC句类理论提出了汉英机器翻译中,要素句蜕处理的具体规则,还结合真实语料进行了验证。     

概念层次网络中对偶性设计

首先对概念层次网络（ＨＮＣ）理论作简要说明,然后根据ＨＮＣ中层符号个性化设计理论给出对偶性设计方案,和偶性的具体表现,并给出对偶性概念具体表现的注解。     

军校的改革在于开放

分析了我军院校发展中存在的问题,提出了培养合格军事人才军校必须采取的措施,阐明了军校教育必须从封闭走向开放,才能在世界军事斗争中处于不败之地。     

Estimating failure time distribution and its parameters based on intermediate data from a Wiener degradation model

Instead of measuring a Wiener degradation or performance process at predetermined time points to track degradation or performance of a product for estimating its lifetime, we propose to obtain the first‐passage times of the process over certain nonfailure thresholds. Based on only these intermediate data, we obtain the uniformly minimum variance unbiased estimator and uniformly most accurate confidence interval for the mean lifetime. For estimating the lifetime distribution function, we propose a modified maximum likelihood estimator and a new estimator and prove that, by increasing the sample size of the intermediate data, these estimators and the above‐mentioned estimator of the mean lifetime can achieve the same levels of accuracy as the estimators assuming one has failure times. Thus, our method of using only intermediate data is useful for highly reliable products when their failure times are difficult to obtain. Furthermore, we show that the proposed new estimator of the lifetime distribution function is more accurate than the standard and modified maximum likelihood estimators. We also obtain approximate confidence intervals for the lifetime distribution function and its percentiles. Finally, we use light‐emitting diodes as an example to illustrate our method and demonstrate how to validate the Wiener assumption during the testing. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

关于半鞅向量随机积分的两个结果

首先利用半鞅Girsanov定理与闭图像定理证明了:若{Xn}是带滤基的完备概率空间(Ω,F,F,P)中的一列半鞅,其中滤基F=(Ft)t≥0满足通常条件,且{Xn}在关于P的Emery拓扑空间中收敛于X,则当概率测度Q相似文献   

攻角对双三角翼旋涡特性影响的数值模拟

采用数值方法研究了双三角翼上涡流运动随攻角的变化规律.计算取层流假设,研究了攻角在5°～30°,76°/40°后掠双三角翼绕流的流场结构随攻角的变化,并对双三角翼上涡破裂现象对流场结构及气动力性能的影响进行了分析.结果表明,双三角翼上的多涡结构存在强烈的相互影响,较大的攻角会导致涡破裂在翼面上发生,严重影响了双三角翼的气动力性能.     

布尔函数的Walsh谱绝对值分布及其性质研究

提出并研究了布尔函数的Walsh谱绝对值分布.指出布尔函数Walsh谱绝对值分布在仿射变换下的不变性,计算了n(n≤5)元布尔函数的Walsh谱绝对值分布,研究了Walsh谱绝对值分布与Walsh谱支撑和Walsh谱中非零取值个数以及其他一些密码学难题的联系,最后研究了布尔函数的Walsh谱绝对值分布的大小.     

Multilateral defense cooperation in the Indo-Asia-Pacific region: Tentative steps toward a regional NATO?

Some U.S. military leaders have asserted that the United States, Japan, Australia, and India and the Republic of Korea are developing multilateral defense cooperation to deter aggression and uphold norms much like North Atlantic Treaty Organization (NATO) has in Europe. Frequent military exercises and China’s threats to freedom of navigation (FoN) and North Korea’s nuclear missiles comprise the motive force for such cooperation. However, cooperation thus far has been trilateral and minimal, given divergent national interests and dispersed geopolitical locations. Cooperation among Japan, Republic of Korea (ROK), and the United States is increasing given the threat, but ROK’s public opinion is divided about Japan. Australia, Japan, and India have increased cooperation with the United States but are reluctant to conduct FoN operations with the United States to challenge China’s expansionism in the South China Sea. If China becomes more aggressive and blocks FoN or seizes territory, development toward an Asian NATO is possible.     

Competitive Statehood in Libya: Governing Differently a Specific Setting or Deconstructing its Weak Sovereign State with a Fateful Drift Toward Chaos?

Abstract

Libya in 2011 witnessed a real process of political change, though different from all the policy-oriented jargon equating transition with a teleological transition to democracy. Due to the resilience of the Qadhafi regime in power and with the essential role of NATO intervention, the process was eased out by a eight-month civil war. Governance in post-Qadhafi Libya was not done through the rebuilding of centralized authorities. But it took the specific form of the emergence of multiple non-state actors embedded in local dynamics and then connected with weakened central authorities that had access to the huge Libyan resources. That raised complex questions about the quality of this mode of governance, especially at a time of pressing problems for Libya and its neighbors, whether direct ones (Tunisia, Egypt, Mali) or farther countries across the Mediterranean sea: terrorism with the expansion of Da’esh into the country and flows of refugees crossing Libya’s uncontrolled borders and flowing into Italy and then Europe by thousands.