等值电路法列写线性网络的状态方程

本文介绍一种手算时用等值电路编写线性网络状态方程的方法。优点是不必列任何方程式,尤其是可以省略消去非状态变量的复杂计算过程。提出一种用检查“量纲”的办法,核对计算是否有误,以便及时纠正。     

Analysis of the mass of behind-armor debris generated by RHA subjected to normal penetration of variable cross-section EFP

Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. So theoretical analysis, numerical simulation and experimental data are combined to analyze the influence of variable cross-section characteristic on the time history of crater radius. Moreover the relationships between time history of crater radius (as well as mass of BAD) and the thickness of RHA (from 30 mm to 70 mm) and the impact velocity of EFP (1650 m/s to 1860 m/s) are also investigated. The results indicate that: 1) being compared to the variable cross-section characteristic is ignored, the theoretical time history of crater radius is in better agreement with the simulation results when the variable cross-section characteristic is considered; 2) being compared to the other three conditions of plug, the theoretical mass of BAD is in the best agreement with the simulation results when the shape of plug is frustum of a cone and the angle between generatrix and bottom is 45° and the axial length of mushroom is considered.     

溅板式层板喷注单元燃烧特性数值分析

为了获得喷注单元结构参数对喷注器燃烧特性的影响规律,利用数值分析方法对单喷嘴溅板式层板喷注单元气-气燃烧特性进行研究,考察燃烧室特征长度及出口层喷嘴宽度对气氧/甲烷流动及燃烧特性的影响。在求解气-气燃烧流场方面,采用带化学反应的湍流N-S方程进行描述,其中化学动力学反应模型采用简化的单步9组分模型。研究结果表明:燃烧室特征长度的增大有利于特征速度效率的增加;该条件下采用溅板式层板喷注单元所对应的燃烧室特征长度约为600 mm。对比分析发现,出口层喷嘴宽度取0.15 mm时,水组分摩尔分数与热力计算值差别最大;当其值取1.05 mm时,燃烧室头部区域截面温度上升最快,取0.45 mm时上升最慢。总的来说,出口层喷嘴宽度取0.75 mm时,燃烧长度最短,燃烧效率最大。     

磁化等离子体对电磁波反射系数的计算分析

为了从理论上分析磁化等离子体对飞行器隐身的机理,采用等效输入阻抗方法计算金属平板前非均匀磁化等离子体层对垂直入射电磁波的功率反射系数,结果表明:电子数密度大小、入射波频率、等离子体碰撞频率和外磁场是功率反射系数的主要影响因素.电子数密度、等离子体碰撞频率取值必须合适,外加磁场才能明显降低等离子体对入射电磁波的功率反射系数.     

混合气体识别的响应等效性与瞬态信号正交分解模型

针对目前混合气体识别大多采用传感器稳态响应信号、基于线性混合假设或大量样本学习,而瞬态响应信号特征分析主要应用非正交分解的问题,提出一种基于响应等效性与瞬态信号正交分解的混合气体识别模型。分析金属氧化物半导体传感器对混合气体的响应特性,建立基于气体响应成分等效性假设的气体非线性混合模型,在此基础上,提出并应用一种新的正交基函数——扩展类Legendre正交基,对气体传感器瞬态响应信号进行分解;通过对正交分解系数与气体浓度的回归分析,验证二者之间的指数型关联关系,并以正交分解系数为特征参数,利用气体非线性等效混合模型对混合气体分解与辨识。实验结果表明,尽管这种混合气体识别模型仅用单一气体检测的先验知识,对混合气体的识别误差仍可达到15%以内。     

全长和埋入式组合抗滑桩在挖断村滑坡中的应用

重庆市奉节县挖断村滑坡规模巨大,滑坡体长180~250m,滑坡体厚15~35m,剩余下滑力达5 337 kN/m,采用了前排全长后排埋入式的新型组合抗滑支挡技术,大大节省了工程投资。介绍了这种新型组合抗滑结构的设计方法,重点介绍了桩的长度计算、各桩承担滑坡推力计算、治理后的监测数据。工程竣工2年的监测数据表明滑坡变形趋于稳定,说明采用全长和埋入式组合抗滑桩治理该滑坡是有效的。     

一个具有相互独立、不同分布服务时间序列的排队模型

讨论的排队模型 ,放宽了GI/G/1系统中“服务时间独立同分布”的限制 ,只要求各服务时间相互独立 ,因而较GI/G/1排队模型能更合理地拟合实际问题 .在此较宽的条件下 ,利用补充变量的方法 ,求得了该排队系统队长的瞬时分布     

Monitoring censored lifetime data with a weighted‐likelihood scheme

Lifetime experiments are common in many research areas and industrial applications. Recently, process monitoring for lifetime observations has received increasing attention. However, some existing methods are inadequate as neither their in control (IC) nor out of control (OC) performance is satisfactory. In addition, the challenges associated with designing robust and flexible control schemes have yet to be fully addressed. To overcome these limitations, this article utilizes a newly developed weighted likelihood ratio test, and proposes a novel monitoring strategy that automatically combines the likelihood of past samples with the exponential weighted sum average scheme. The proposed Censored Observation‐based Weighted‐Likelihood (COWL) control chart gives desirable IC and OC performances and is robust under various scenarios. In addition, a self‐starting control chart is introduced to cope with the problem of insufficient reference samples. Our simulation shows a stronger power in detecting changes in the censored lifetime data using our scheme than using other alternatives. A real industrial example based on the breaking strength of carbon fiber also demonstrates the effectiveness of the proposed method. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 631–646, 2017     

多样化军事任务纪检监察工作的几个着力点

多样化军事任务纪检监察工作应把握以下着力点：把严格执行和维护各项纪律作为纪检监察工作的首要任务,确保部队令行禁止;把确保打赢作为纪检监察工作的根本目标,坚持正确的思想方法;把坚持依法执行任务作为纪检监察工作的重点环节,确保政策法规落到实处;把加强纪检监察队伍自身建设作为发挥职能作用的重要前提,建立完善的组织机构和工作机制。     

综合火控系统对地轰炸精度分析仿真

针对航空轰炸武器火控系统精度分析问题,分别建立了数值微分算法和蒙特卡洛算法模型,并开发了仿真分析软件.给出了两种模型的推导过程,以及微分步长的优化方法.利用本算法软件对某型火控系统进行精度分析仿真,并对多组典型投弹条件的仿真结果进行分析.结果表明,两种算法优势互补,能有效地对火控系统进行精度分析,对改进系统设计、提高系...