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81.
一种大功率开关电源的设计及效能分析 总被引:1,自引:1,他引:0
在实验研究的基础上 ,提出一种采用IGBT器件的高效大功率开关电源的设计方法 ,着重分析了系统主回路中影响效率的各主要因素以及应采取的对策 ,实验证明可使效率达 90 %以上。 相似文献
82.
83.
胡玉贵 《军械工程学院学报》1994,(4)
本文分析了柴油机的最大扭矩、扭矩储备系数、喷油系统喷油量与柱塞几何供油量的差异和变化规律,认为这3个参数的现行定义不尽合理,并给出了新的定义。 相似文献
84.
本文依据师弹药保障的特点,通过对历次作战军械保障资料的统计研究,建立了动态自适应弹药消耗预计模型和弹药保障方案目标规划模型,并给出了计算机程序实现框图。 相似文献
85.
本文针对备件供应决策问题,提出了备件保证度的概念,阐述了保证度与使用可用度的关系,认为影响保证度的主要因素是:备件修复时间、备件获取时间、库存水平、设备数量及复杂程度和备件需求率,分析了二级供应系统的普遍性和代表性,并应用概率论的原理,建立了备件保证度模型。 相似文献
86.
潜艇开关电源的应用及发展方向 总被引:1,自引:1,他引:0
张鹰 《海军工程大学学报》1999,(3)
研究了潜艇开关电源的应用现状,分析讨论了3 种最基本的高频开关型变流电路的工作原理,指出潜艇开关电源今后的发展方向:开关频率高频化,硬件结构模块化,控制系统数字化及产品性能绿色化,并在全艇采用分布式配电系统对各舱室负载独立供电. 相似文献
87.
弹药保障效果评价的AHP-FUZZY方法 总被引:2,自引:1,他引:1
简要分析了我军弹药保障效果评价工作的不足之处,在此基础上,综合运用层次分析技术(AHP)和模糊评判技术(Fuzzy),对战场上弹药保障效果评价进行了探讨。运用AHP法建立了弹药保障效果评价的层次结构模型,并详细论述了运用Fuzzy方法评价弹药保障效果的实现过程和注意问题。 相似文献
88.
We consider a distribution system consisting of a central warehouse and a group of retailers facing independent stochastic demand. The retailers replenish from the warehouse, and the warehouse from an outside supplier with ample supply. Time is continuous. Most previous studies on inventory control policies for this system have considered stock‐based batch‐ordering policies. We develop a time‐based joint‐replenishment policy in this study. Let the warehouse set up a basic replenishment interval. The retailers are replenished through the warehouse in intervals that are integer multiples of the basic replenishment interval. No inventory is carried at the warehouse. We provide an exact evaluation of the long‐term average system costs under the assumption that stock can be balanced among the retailers. The structural properties of the inventory system are characterized. We show that, although it is well known that stock‐based inventory control policies dominate time‐based inventory control policies at a single facility, this dominance does not hold for distribution systems with multiple retailers and stochastic demand. This is because the latter can provide a more efficient mechanism to streamline inventory flow and pool retailer demand, even though the former may be able to use more updated stock information to optimize system performance. The findings of the study provide insights about the key factors that drive the performance of a multiechelon inventory control system. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 637–651, 2013 相似文献
89.
Recent events in Iran and elsewhere demand a reevaluation of the need for increasing nuclear fuel supplies and assuring reliable flow of fuel to nuclear power user states vis-à-vis the need for strengthened security for all countries against the use of weapons of mass destruction (WMD). The right of countries to a guaranteed supply of nuclear energy for peaceful uses must be balanced with the global community's desire to limit flows of nuclear material and sensitive nuclear facilities that could create opportunities for nuclear proliferation. This article proposes elements of an international regime of fresh fuel supply and spent fuel disposal that will guarantee fresh fuel supplies to countries honoring their obligations under the Treaty for the Non-Proliferation of Nuclear Weapons (NPT), while reducing concerns about diversion of spent fuel for weapons purposes. A specific application to countries with small pre-commercial uranium enrichment plants is also proposed. 相似文献
90.
《Arms and Armour》2013,10(1):30-39
AbstractA recent re-examination of the arms and armour collection at the British Museum has led to the identification of a 17th-century pikeman's armour clearly associated with the city of Antwerp in modern Belgium, the only example of its kind. The three pieces: a pot, breastplate and backplate, are part of a collection bequeathed to the museum by William Burges in 1881. All three pieces can be dated to circa 1635 and are stamped with the arms of Antwerp, a stylised depiction of Antwerp castle between two hands derived from the blazon of the Margrave of Antwerp. The armour is indistinguishable from contemporary Dutch production and it is unclear whether it was made in Antwerp or whether the addition of the arms simply suggests a use in the city. 相似文献