Configurationmodelofpartial repairablesparesunder batch ordering policy based on inventory state

Rational planning of spares configuration project is an effective approach to improve equipment availability as well as reduce life cycle cost （LCC）. With an analysis of various impacts on support system, the spares demand rate forecast model is constructed. According to systemic analysis method, spares support effectiveness evaluation indicators system is built, and then, initial spares configuration and optimization method is researched. To the issue of discarding and con-sumption for incomplete repairable items, its expected backorders function is approximated by Laplace demand distribution. Combining the （s-1, s） and （R, Q） inventory policy, the spares resup-ply model is established under the batch ordering policy based on inventory state, and the optimi-zation analysis flow for spares configuration is proposed. Through application on shipborne equipment spares configuration, the given scenarios are analyzed under two constraint targets：one is the support effectiveness, and the other is the spares cost. Analysis reveals that the result is consistent with practical regulation;therefore, the model＇s correctness, method＇s validity as well as optimization project＇s rationality are proved to a certain extent.     

Dynamic airspace configuration method based on a weighted graph model

This paper proposes a new method for dynamic airspace configuration based on a weighted graph model. The method begins with the construction of an undirected graph for the given airspace, where the vertices represent those key points such as airports, waypoints, and the edges represent those air routes. Those vertices are used as the sites of Voronoi diagram, which divides the airspace into units called as cells. Then, aircraft counts of both each cell and of each air-route are computed. Thus, by assigning both the vertices and the edges with those aircraft counts, a weighted graph model comes into being. Accordingly the airspace configuration problem is described as a weighted graph partitioning problem. Then, the problem is solved by a graph partitioning algorithm, which is a mixture of general weighted graph cuts algorithm, an optimal dynamic load balancing algorithm and a heuristic algorithm. After the cuts algorithm partitions the model into sub-graphs, the load balancing algorithm together with the heuristic algorithm transfers aircraft counts to balance workload among sub-graphs. Lastly, airspace configuration is completed by determining the sector boundaries. The simulation result shows that the designed sectors satisfy not only workload balancing condition, but also the constraints such as convexity, connectivity, as well as minimum distance constraint.     

基于EEMD气液两相流差压信号时频分析

为研究气液两相流流动过程的动态特性,采用V形内锥作为测量装置,通过高频差压变送器获得不同流型下的动态信号,提出了一种基于总体平均经验模式分解（EEMD）的气液两相流时频分析方法。通过对不同流型下的气液两相流的差压信号进行分析,研究了气液两相流的流动机理,为气液两相流流型及流量的准确测量奠定理论基础。分析发现EEMD的抗混分解能力很好,可以准确地提取两相流差压信号的频率成分及其时变情况,为今后两相流的识别提供理论基础,具有较高的工程应用价值。     

超燃冲压发动机燃烧室热力喉道的一种新型计算方法

为了研究超燃冲压发动机总体性能一维计算方法,采用一种新的热力喉道计算方法,由燃烧室出口开始沿上游依次进行声速截面假设,利用流量方程、能量方程及总静压方程计算出该截面所有一维参数,再利用解析方法,计算该假设截面的临界燃烧效率梯度,并由此给出热力喉道判断条件,求出热力喉道的位置。用该方法分别对马赫数3.5~6飞行条件下的发动机模型进行了计算,并与传统方法的计算结果进行对比,结果表明:该方法能够快速计算热力学喉道,具有良好的可行性,与传统方法之间的误差均在6%以内。     

旋翼机总体设计的几个问题

结合自转旋翼特性及旋翼机设计的独特性,在直升机空气动力学和飞行动力学原理的基础上修改并建立了计算模型,解决了旋翼机气动布局、总体参数及旋翼设计等方面的难题.     

旅游电子票务系统设计

为提高旅游公司及其景区的管理水平和服务质量,采用先进的信息技术,设计出一个由总公司和各景区所构成的旅游电子票务系统,能够实现计算机实时售票、验票、统计、汇总、查询、报表等全方位的实时监控及门票管理,提升旅游企业竞争力。     

“高分一号”卫星首批影像对外发布

国家国防科技工业局今天对外公布"高分一号"卫星获取的首批影像图。据了解,"高分一号"卫星工程大大提升了我国对地观测卫星的总体观测能力,未来将为国土、环境、农业等领域提供精准服务。     

2014广告赞助计划已启动

《全球卫星固定业务运营商25强资源手册》是编辑部重磅推出的卫星通信领域研究类产品,介绍了最新的全球卫星产业状况、近5年的卫星固定业务运营商排行、各运营商的发展情况和在轨卫星资源情况(运营商在轨卫星分布图、卫星总体参数指标、有效载荷参数指标及覆盖图)。本书全彩印刷,B5版,330余页,拟于2014年起公开出版发行,每年更新发布,可为卫星运营商、卫星制造商、发射服务提供商、通信产品制造企业、通信服务提供商、投资商、相关主管部门等提供长期的信息服务和决策支持。     

斜爆震发动机研究进展与技术挑战

斜爆震发动机（Oblique detonation engine, ODE）采用驻定斜爆震波（Oblique detonation wave, ODW）实现高超声速气流中燃料化学能向推进系统机械能的高效转化，可大幅提升吸气式飞行速域上限，具有重要发展潜力和应用价值。本文从早、中、近期3个阶段概述ODE发展历程，总结当下斜爆震燃烧及发动机的研究现状。重点从发动机设计角度综述国内外在斜爆震燃烧组织、燃料喷注掺混以及总体性能与内流设计3方面的研究进展。深入分析了总体约束下的内外流一体化设计、高超声速气流中的燃料喷注掺混、复杂来流条件下的稳定燃烧组织、高热载荷防护以及超高速工况试验条件5大技术挑战及重点关注方向，为后续深入技术攻关及应用提供参考。