Fabrication and characterization of Al-CuO nanocomposites prepared by sol-gel method

In this study, Al-CuO nanocomposites were fabricated by sol-gel method. As a contrast, the thermite was prepared by physical mixing at the equivalence ratio of 0.5, 1, 2, respectively. The intermediates and samples as prepared were characterized by SEM and XRD. The exothermic properties of the two samples prepared at different equivalence ratios were tested and the reaction products were characterized by XRD. The SEM results show that the sample prepared by the sol-gel method demonstrates a micron-sized agglomerated sphere formed by a mutual wrapping of Al NPs and CuO NPs, and the particles are evenly distributed in the agglomerate. In addition, when the content of Al powder is seriously insufficient, the heat release of the sample prepared by physical mixing is 1.6 times that of by sol-gel method. With the increase of Al powder content, the exothermic properties of Al/CuO NPs prepared by sol-gel method began to increase significantly compared with physical mixing and the difference is 1.5 times when the equivalence ratio increases to 2. It can be concluded that the reason for this result may be attributed to the different mass transfer modes of components due to the different morphologies of samples.     

RPL路由协议中基于投票法的黑洞攻击检测算法

物联网容易遭受多类拒绝服务攻击,其中黑洞攻击是最严重的攻击之一.为此,提出基于投票法的黑洞攻击检测算法(Voting Method-based Blackhole Attack Detection,VMBAD).通过VMBAD算法检测RPL协议上的黑洞攻击.先通过过滤器构建嫌疑节点,再验证嫌疑节点的行为,各节点作出自己的决策意见,并传输到边界路由(Bor-der Router,BR).接收后,BR利用投票机制融合各节点的决策意见,进行最终的决策,进而判断节点是否为黑洞攻击节点.一旦认定为黑洞攻击,就将黑洞攻击节点与网络隔离,使其不参与RPL路由.仿真结果表明,VMBAD算法能够有效地检测黑洞攻击节点,并且通过排除攻击节点,提高了数据包传递率.     

自由电子激光的粒子模拟

文中简单介绍了自由电子激光粒子模拟方法,用■维完全相对论性电磁模程序模拟了相对论电子束通过回旋磁场产生电磁辐射的过程,并作了理论解释;研究了纵向引导磁场对能量转换效率的影响。     

Repairable consecutive‐k‐out‐of‐n: F system with Markov dependence

In this article, a model for a repairable consecutive‐k‐out‐of‐n: F system with Markov dependence is studied. A binary vector is used to represent the system state. The failure rate of a component in the system depends on the state of the preceding component. The failure risk of a system state is then introduced. On the basis of the failure risk, a priority repair rule is adopted. Then the transition density matrix can be determined, and the analysis of the system reliability can be conducted accordingly. One example each of a linear and a circular system is then studied in detail to explain the model and methodology developed in this paper. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 18–39, 2000     

模糊控制理论在舰用燃气轮机控制系统中的应用探讨

对模糊控制进行了介绍 ,构造出一种模糊控制器 ,将其编成微机程序 ,使其完成模糊控制功能 .研究它在舰用燃气轮机控制中的应用 .进行了多次燃气轮机模拟试车 ,当对燃气轮机控制系统加入扭矩和振动等控制信号时 ,燃气轮机的稳态和加速过程都获得了良好的控制品质 ,为舰用燃气轮机的控制探索了一种新方法     

基于小波变换的宽带模糊函数估计器

提出了一种基于小波变换的宽带模糊函数参数估计器,即通过交互小波变换计算宽带模糊函数,取宽带模糊函数模的平方的峰值点对应参数作为目标时延与时间伸缩的估计．仿真结果表明,该估计器的估计性能好于直接模糊函数估计器,且计算方便,非常适合于实际宽带处理系统应用．     

加强计算机基础教育问题的探索

指出了高等军事院校非计算机专业人才加强计算机基础教育的重要意义,结合我院的现状,提出了加强计算机基础教育的措施和模式.     

装甲装备器材装箱优化研究

在对装甲装备器材进行科学分类的基础上,着重研究了直方体类器材的装箱优化问题,解决了目前装甲装备器材的类型与品种多、形状差异大,人工选择器材外包装箱时费时费力的问题.     

Adaptive importance sampling for extreme quantile estimation with stochastic black box computer models

Quantile is an important quantity in reliability analysis, as it is related to the resistance level for defining failure events. This study develops a computationally efficient sampling method for estimating extreme quantiles using stochastic black box computer models. Importance sampling has been widely employed as a powerful variance reduction technique to reduce estimation uncertainty and improve computational efficiency in many reliability studies. However, when applied to quantile estimation, importance sampling faces challenges, because a good choice of the importance sampling density relies on information about the unknown quantile. We propose an adaptive method that refines the importance sampling density parameter toward the unknown target quantile value along the iterations. The proposed adaptive scheme allows us to use the simulation outcomes obtained in previous iterations for steering the simulation process to focus on important input areas. We prove some convergence properties of the proposed method and show that our approach can achieve variance reduction over crude Monte Carlo sampling. We demonstrate its estimation efficiency through numerical examples and wind turbine case study.     

IIR数字滤波器联立优化CAD

文中介绍了多目标联立最佳逼近CAD方法,对各种设计方法的性能作了分析比较,提出了改善途径。程序在IBM-PC/XT微机上运行通过,文中给出了应用线性相位IIR数字滤波器线性规划逼近法设计的低通实例。