基于性能的装备采购合同商选择研究

根据基于性能的装备采购目标,在考虑合同商满足军方提出的性能指标的基础上,从合同商的资质、生产技术能力、装备价格成本、装备保障性能、管理运营情况和双方协商沟通水平等方面建立了合同商选择评价指标体系,并运用层次变权综合决策方法进行综合评判。案例分析表明：该方法能充分反映决策者的意愿,使合同商的选择更好地满足基于性能的装备采购的需要。     

车用再制造发动机验收检验台架磨合规范试验研究

对未经磨合的再制造发动机新品进行动力性能试验,试验结果与原机标准相差较大,经分析后认为未进行充分磨合是性能不达标的主要原因。针对再制造发动机的出厂验收技术特点,制定了小负荷循环磨合规范,并对起初推断进行了试验验证。根据磨合过程中发动机动力性能的变化规律,通过试验对磨合规范进行了优化,总结出了快速有效的台架磨合规范。试验结果表明：快速磨合规范不仅能够提高磨合效率,而且保证了磨合效果。     

A reusable planar triggered spark-gap switch batched-fabricated with PCB technology for medium-and low-voltage pulse power systems

Triggered spark-gap switch is a popular discharge switch for pulse power systems. Previous studies have focused on planarizing this switch using thin film techniques in order to meet the requirements of compact size in the systems. Such switches are one-shot due to electrodes being too thin to sufficiently resist spark-erosion. Additionally, these switches did not employ any structures in securing internal gas composition, resulting in inconsistent performance under harsh atmospheres. In this work, a novel planar triggered spark-gap switch (PTS) with a hermetically sealed cavity was batched-prepared with printed circuit board (PCB) technology, to achieve reusability with low cost. The proposed PTS was inspected by micro-computed tomography to ensure PCB techniques meet the requirements of machining precision. The results from electrical experiments demonstrated that PCB PTS were consistent and reusable with lifespan over 20 times. The calculated switch voltage and circuit current were consistent with those derived from real-world measurements. Finally, PCB PTS was used to introduce hexanitrostilbene (HNS) pellets in a pulse power system to verify its performance.     

Effect of metal powders on explosion of fuel-air explosives with delayed secondary igniters

In order to improve the energy level of fuel air explosive(FAE) with delayed secondary igniters, high energetic metal powders were added to liquid fuels mainly composed of ether and isopropyl nitrate. Metal powders' explosive properties and reaction mechanisms in FAE were studied by high-speed video, pressure test system, and infrared thermal imager. The results show that compared with pure liquid fuels, the shock wave overpressure, maximum surface fireball temperature and high temperature duration of the mixture were significantly increased after adding high energetic metal powder. The overpressure values of the liquid-solid mixture at all measuring points were higher than that of the pure liquid fuels. And the maximum temperature of the fireball was up to 1700 ℃, which was higher than that of the pure liquid fuels. After replacing 30％of aluminum powder with boron or magnesium hydride, the shock wave pressure of the mixture was further increased. The high heat of combustion of boron and the hydrogen released by magnesium hydride could effectively increase the blast effect of the mixture. The improvement of the explosion performance of boron was better than magnesium hydride. It shows that adding high energetic metal powder to liquid fuels can effectively improve the explosion performance of FAE.     

灰色分析法在物流绩效评价中的应用研究

提出了基于灰色关联度的物流绩效灰色评价模型。阐明了灰色分析法进行物流绩效评价的方法,并与文献[1]的方法进行了比较。结果表明灰关联分析方法应用于物流绩效评价是有效的、可行的,且具有分析全面、方法简便、易于计算机实现等特点。     

网络性能综合评估方法IEMoNP的设计和实现

由于孤立的网络性能指标(测度)不能满足全局性或整体性网络性能评估的需要,文中给出了网络性能综合指数IPI和网络运行稳定性指数SI的概念、定义和计算公式.IPI和SI反映了相对基准时刻的网络性能状况.在此基础上,进一步提出了基于IPI和SI的网络性能综合评估方法IEMoNP.最后,通过一个应用示例表明,IEMoNP能够为全局性或整体性的网络性能评估提供支持.     

凝结水泵三维流场数值模拟与分析

为深入理解和分析电站凝结水泵性能,采用计算流体力学方法(CFD)对其内部复杂的三维流场进行了数值模拟与分析.首先,建立了某三级凝结水泵各部件几何模型,并对其进行网格划分.通过求解RANS方程对凝结水泵内部三维流场进行数值求解,湍流流动采用SST模型进行模拟.计算得到该泵若干工况下的扬程和功率等性能参数和泵内部流动特征,计算结果与试验数据吻合很好.模拟结果及分析表明:采用CFD方法模拟结构复杂的凝结水泵内部流动和进行性能预报是可行的.通过内流场分析还发现导叶体等部件的设计有可改进之处.     

不同损失函数下指数-泊松分布的Bayes估计

基于定数截尾样本,在熵损失、Linex损失和刻度平方损失函数下,给出了指数-泊松分布参数的Bayes估计,并证明了所给估计都是容许的。最后给出了随机模拟例子,对所给估计结果的优良性进行了分析比较。     

基于任务需求的系统保障性目标确定

从系统任务需求出发,提出了使用性能特性和保障特性的概念,并分析了二者之间的相互关系,同时给出了保障性目标的组成、内容和要求。介绍了确定保障性目标所用的方法,包括使用研究,剖面制定,比较分析,目标评估与改进以及目标实现。最后,给出了保障性目标要求确定的案例。     

不同磁浮列车外形的气动性能比较

上海磁浮列车由于流线型车头较短,气动性能并不理想,根据国内厂家给定的列车横断面尺寸和对气动性能的要求,对国产磁浮列车气动外形进行多方案设计,通过求解三维可压N-S方程和k-ε双方程湍流模型,对提出的磁浮列车各种外形方案的气动性能进行数值模拟计算,并根据计算结果进一步改进气动外形,如此反复,直至得出气动性能和外观最优的磁浮列车外形。在最终选定的三种设计方案中,方案3由于水平投影轮廓线较窄、最大纵剖面轮廓线曲率较小,其整车空气阻力和列车交会压力波都较其它两种方案要小,因此为最佳的气动外形方案。通过比较分析,此次选用的国产磁浮列车外形,列车以430km/h运行时三节车总的空气阻力为33.84kN,而上海磁浮列车为54.07kN;国产磁浮列车最大列车交会压力波幅值为2913Pa,而在同等条件下上海磁浮列车为3827Pa,其气动性能明显优于上海磁浮列车。