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1.
以冲压增程弹为应用背景进行了进气道设计.结合增程弹的特点,讨论了轴对称进气道中心锥参数、喉道参数、外罩参数的选择.特别对进气道唇口处参数、扩张段角度设计方法进行了分析.设计了单锥混压式、单锥外压式以及双锥混压式三种进气道,并进行了数值模拟.分析了进气道主要设计参数对其性能的影响.数值结果表明,就增程弹的性能要求而言,双锥混压式进气道的性能较高. 相似文献
2.
公共场所人员安全疏散评价方法探讨 总被引:2,自引:0,他引:2
公共场所安全疏散评价对于确保火灾中人员的生命安全具有重要意义。基于“性能化”防火设计的思想,对影响公共场所安全疏散的因素进行了分析,并对安全疏散的必要性能和评价程序进行了较为全面的探讨,其中包括烟气的评价、人员疏散能力的评价、疏散路线合理性的评价、疏散对策的评价等,目的在于通过合理的评价方法得出合理的疏散性能,为减少公共场所火灾造成的人员伤亡和财产损失提供帮助。 相似文献
3.
郭振峰 《装甲兵工程学院学报》2002,16(1):1-5
分析了现代战场条件下坦克生存面临的重要威胁,强调了加强坦克主动式防护系统研究的重要性,并提出了加强我军坦克主动式防护系统的研究应遵循的原则和技术途径。 相似文献
4.
驱动器并联方式能有效扩大驱动容量,但该方式容易引入环流。为了抑制环流,分析了两个独立电源供电的两台驱动器并联结构系统,阐述了环流的特性,并提出了基于环流反馈的控制结构。这种控制结构通过环流的反馈,只需要控制调整其中一台驱动器,就可减小两台驱动器输出电压的差异,实现环流抑制。仿真结果表明:这种控制结构降低了控制的复杂性,能够抑制环流,实现独立电源供电的无刷直流电机驱动器并联。 相似文献
5.
针对机载航电系统自身辐射源特性,提出一种不依赖敌方探测设备的机载航电系统射频隐身性能评估方法。分析机载航电系统设备在极化域、波形域、能量域中影响射频隐身性能的因素,构建极化域、能量域、波形域射频隐身指标,打破常规的"辐射-接收"模型的隐身性能评估方法,建立基于机载航电系统自身辐射信号工作状态和工作参数的射频隐身定量评估方法。对机载雷达系统进行仿真评估,结果表明,该评估方法能正确反映机载雷达系统的射频隐身性能。 相似文献
6.
Having a robustly designed supply chain network is one of the most effective ways to hedge against network disruptions because contingency plans in the event of a disruption are often significantly limited. In this article, we study the facility reliability problem: how to design a reliable supply chain network in the presence of random facility disruptions with the option of hardening selected facilities. We consider a facility location problem incorporating two types of facilities, one that is unreliable and another that is reliable (which is not subject to disruption, but is more expensive). We formulate this as a mixed integer programming model and develop a Lagrangian Relaxation‐based solution algorithm. We derive structural properties of the problem and show that for some values of the disruption probability, the problem reduces to the classical uncapacitated fixed charge location problem. In addition, we show that the proposed solution algorithm is not only capable of solving large‐scale problems, but is also computationally effective. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2010 相似文献
7.
This article treats an elementary optimization problem, where an inbound stream of successive items is to be resequenced with the help of multiple parallel queues in order to restore an intended target sequence. Whenever early items block the one item to be currently released into the target sequence, they are withdrawn from their queue and intermediately stored in an overflow area until their actual release is reached. We aim to minimize the maximum number of items simultaneously stored in the overflow area during the complete resequencing process. We met this problem in industry practice at a large German automobile producer, who has to resequence containers with car seats prior to the assembly process. We formalize the resulting resequencing problem and provide suited exact and heuristic solution algorithms. In our computational study, we also address managerial aspects such as how to properly avoid the negative effects of sequence alterations. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 401–415, 2016 相似文献
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Considering a supply chain with a supplier subject to yield uncertainty selling to a retailer facing stochastic demand, we find that commonly studied classical coordination contracts fail to coordinate both the supplier's production and the retailer's procurement decisions and achieve efficient performance. First, we study the vendor managed inventory (VMI) partnership. We find that a consignment VMI partnership coupled with a production cost subsidy achieves perfect coordination and a win‐win outcome; it is simple to implement and arbitrarily allocates total channel profit. The production cost subsidy optimally chosen through Nash bargaining analysis depends on the bargaining power of the supplier and the retailer. Further, motivated by the practice that sometimes the retailer and the supplier can arrange a “late order,” we also analyze the behavior of an advance‐purchase discount (APD) contract. We find that an APD with a revenue sharing contract can efficiently coordinate the supply chain as well as achieve flexible profit allocation. Finally, we explore which coordination contract works better for the supplier vs. the retailer. It is interesting to observe that Nash bargaining solutions for the two coordination contracts are equivalent. We further provide recommendations on the applications of these contracts. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 305–319, 2016 相似文献