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排序方式: 共有639条查询结果,搜索用时 31 毫秒
601.
采用液相烧结成形工艺制备了90W-Ni-Fe合金棒,通过分析烧结态钨合金的组织形貌和力学性能,观察合金的断口组织形貌,研究了烧结工艺对高比重钨合金组织性能的影响,认为减少W-W界面,增加W-W界面的结合强度,是提高烧结态钨合金力学性能的有效途径。  相似文献   
602.
讨论了维恩位移定律2种表述之间的关系,并与麦克斯韦分子分布函数的峰值相关量进行对比,说明原始的维恩表述是由实验决定的.并对2种表述的物理意义作了阐述.  相似文献   
603.
指挥控制系统是综合电子信息系统的核心,是作战效能的"倍增器"和作战指挥的"神经中枢".从"网-云-端"的结构出发,分析了新型指挥控制系统的总体架构和组成关系;通过分析美国国防部体系结构框架(DoDAF2.0),提出了基于DoDAF2.0的新型指挥控制系统体系结构建模流程;采用结构化和面向对象相结合的方法,设计了新型指挥控制系统作战视角、服务视角、能力视角以及系统视角的关键模型,为系统的具体设计与开发、系统评估与分析提供可靠的模型支持.  相似文献   
604.
许世林  迟铭  王海波 《国防科技》2021,42(5):114-118
在新军事变革的背景下,军队会计流程存在不适应新管理体制需要、信息技术应用对会计流程再造力度不够、军队会计科目设置影响流程等问题。本文从界定军队会计流程的含义入手,提出了优化军队会计流程、建立智能化军队会计信息系统的四项策略,即重塑军队会计流程体系、重构军队会计信息系统、调整军队会计科目体系以及完善各流程会计处理方法。优化军队会计流程、建设智能化军队会计信息系统,不仅能够反映军事经济活动的历史信息,还能为不同类型的信息使用者提供预测、决策等支持,并有利于改善军队会计核算质量,准确反映各类资产负债的价值信息和单位的真实财务状况,对于提高军队会计信息质量具有一定的借鉴意义。  相似文献   
605.
In this work, NH2-substituted oxazoles and NO2/NF2/NHNO2-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles, respectively, in order to develop new bridge-ring insensitive high energy compounds through the Diels-Alder reaction between them. The reaction type, reaction feasibility and performance of reaction products were investigated in detail theoretically. The results showed that dienes most possibly react with dienophiles through the HOMO-diene controlled normal Diels-Alder reaction at relatively low energy barrier. Tetranitroethylene could react with the designed dienes much more easily than other dienophiles, and was employed to further design 29 new bridge-ring energetic compounds. Due to high heat of formation, density and oxygen balance, all designed bridge-ring energetic compounds have outstanding detonation performance, 16 of them have higher energy than HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and 2 others even possess comparative energy with the representative of high energy compounds CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane). The predicted average h50 value of these bridge-ring energetic compounds is 83 cm, showing their low impact sensitivity. The NH2 groups could obviously impel the proceeding of Diels-Alder reactions, but would slightly decrease the energy and sensitivity performance. In all, the new designed bridge-ring compounds have both high energy and low sensitivity, and may be produced through Diels-Alder reactions at relatively low energy barrier. This paper may be helpful for the theoretical design and experiment synthesis of new advanced insensitive high energy compounds.  相似文献   
606.
An effective hybrid optimization method is proposed by integrating an adaptive Kriging (A-Kriging) into an improved partial swarm optimization algorithm (IPSO) to give a so-called A-Kriging-IPSO for maxi-mizing the buckling load of laminated composite plates (LCPs) under uniaxial and biaxial compressions. In this method, a novel iterative adaptive Kriging model, which is structured using two training sample sets as active and adaptive points, is utilized to directly predict the buckling load of the LCPs and to improve the efficiency of the optimization process. The active points are selected from the initial data set while the adaptive points are generated using the radial random-based convex samples. The cell-based smoothed discrete shear gap method (CS-DSG3) is employed to analyze the buckling behavior of the LCPs to provide the response of adaptive and input data sets. The buckling load of the LCPs is maximized by utilizing the IPSO algorithm. To demonstrate the efficiency and accuracy of the proposed methodology, the LCPs with different layers (2, 3, 4, and 10 layers), boundary conditions, aspect ratios and load patterns (biaxial and uniaxial loads) are investigated. The results obtained by proposed method are in good agreement with the literature results, but with less computational burden. By applying adaptive radial Kriging model, the accurate optimal results-based predictions of the buckling load are obtained for the studied LCPs.  相似文献   
607.
Presented herein is an experimental study on the combustion of B4C/KNO3 binary pyrotechnic system.Combustion products were tested using X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive spectrometer(EDS).According to the results of tests and CEA calculation,the combustion reaction equation was established.The flames and burning rates were recorded by a high speed camera and a spectrophotometer.The effect of B4C particle size on the thermal sensitivity of B4C/KNO3 was investigated by differential scanning calorimetry(DSC)techniques.In addition,a reliable method for calculating the flame temperature was proposed.Based on the results of experiments,the combustion reaction mechanism was briefly analyzed.The burning rate,flame temperature and thermal sensitivity of B4C/KNC3 increase with the decrease of B4C particle size.The mass ratio of B4C/KNO3 has a great effect on combustion properties.Oxidizer-rich compositions have low flame temperatures,low burning rates,and provide green light emission.The combustion reactions of fuel-rich compositions are vigorous,and the B4C/KNO3 with mass ratio of 25:75 has the highest burning rate and the highest flame temperature.  相似文献   
608.
This paper presents a comprehensive review of the research studies on direct energy system effect on aircraft composite structures to develop a good understanding of state-of-the-art research and devel-opment in this area. The review begins with the application of composite materials in the aircraft structures and highlights their particular areas of application and limitations. An overview of directed energy system is given. Some of the commonly used systems in this category are discussed and the working principles of laser energy systems are described. The experimental and numerical studies re-ported regarding the aircraft composite structures subject to the effect of directed energy systems, especially the laser systems are reviewed in detail. In particularly, the general effects of laser systems and the relevant damage mechanisms against the composite structures are reported. The review draws attention to the recent research and findings in this field and is expected to guide engineers/researchers in future theoretical, numerical, and experimental studies.  相似文献   
609.
孙健  雷鸣  朱惠民 《火力与指挥控制》2021,46(8):177-179,185
针对舰空导弹武器系统抗干扰能力考核需求,提出一种试验方法,基于舰空导弹武器系统的制导控制系统半实物仿真试验对多种干扰环境下的武器系统抗干扰能力进行逐一检验,通过外场飞行试验进行典型工况下的验证,该方法实现了对舰空导弹武器系统抗干扰成功概率的有效考核,还可以支撑对防空导弹武器系统在单一、复合干扰形式下的抗干扰能力指标的评估.  相似文献   
610.
针对无人集群作战中的分工合作问题,提出了一种基于演化博弈的结构化集群协作控制方法.分析无人集群分工合作需求,基于演化博弈理论,构建结构化集群分工合作模型;在此基础上,理论推导模型的演化动力学过程及博弈均衡解,得出集群分工合作的形成条件;最后,以集群火力打击任务为想定,仿真规则图及一般拓扑上的集群策略演化过程,仿真结果与理论推导相印证,证明了模型方法的合理性与可行性,为相关理论向实际应用转化提供了初步和有意义的探索.  相似文献   
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