加强三维制图教学 促进部队装备建设

为了提高武警部队装备研发的设计速度与水平,从满足部队装备建设的实际需要出发,阐述了军事装备学科的发展思路与方向。结合部队装备仿真设计和创新研制实例,简述了实体参数化设计软件Pro／Engineer的功能特点,阐明了加强三维制图教学的必要性及其在部队装备建设中的重要作用,以及不同学历层次Pro／Engineer的教学内容。对促进军事装备学本科与研究生教育,提高部队装备的开发建设水平具有意义。     

冲击噪声背景下引信目标方位估计方法研究

针对在冲击噪声条件下基于高斯噪声模型的目标检测方法性能退化的缺点,提出了一种新的引信目标方位估计方法。该方法引入α稳定分布模型对冲击噪声建模,通过对引信阵列天线接收信号共变矩阵的特征分解估计噪声子空间,再依据最小范数算法实现了对目标方位的估计。计算机仿真实验证明了所提出新方法的有效性。     

关于新时期反恐情报分析模型的建构

反恐情报分析是反恐情报工作的重中之重,建构反恐情报分析模型不仅是新时期公安大情报发展的必由之路,同时也为新时期反恐斗争拓宽了解决途径。     

元器件性能退化信息的系统性能可靠性评估

性能可靠性方法为解决现代工程实际中的高可靠、长寿命、小子样产品的可靠性建模分析提供了途径.目前的性能可靠性研究主要是针对元器件开展的,对系统性能可靠性进行研究时通常需要将其看作一个元器件,需要得到系统的性能退化数据,在某些情况下,得到系统的性能退化数据比较困难.实际上,由于元器件的性能退化导致系统性能的变化,因而可以利...     

Effect of organo-modified montmorillonite nanoclay on mechanical,thermal and ablation behavior of carbon fiber/phenolic resin composites

The mechanical, thermal and ablation properties of carbon phenolic (C-Ph) composites (Type-I) rein-forced with different weight percentages of organo-modified montmorillonite (o-MMT) nanoclay have been studied experimentally. Ball milling was used to disperse different weight (wt) percentages (0, 1,2,4,6 wt.％) of nanoclay into phenolic resin. Viscosity changes to resin due to nanoclay was studied. On the other hand, nanoclay added phenolic matrix composites (Type-II) were prepared to study the dispersion of nanoclay in phenolic matrix by small angle X-ray scattering and thermal stability changes to the matrix by thermogravimetric analyser (TGA). This data was used to understand the mechanical, thermal and ablation properties of Type-I composites. Inter laminar shear strength (ILSS), flexural strength and flexural modulus of Type I composites increased by about 29％, 12％and 7％respectively at 2 wt.％ addition of nanoclay beyond which these properties decreased. This was attributed to reduced fiber volume fraction (％Vf) of Type-I composites due to nanoclay addition at such high loadings. Mass ablation rate of Type-I composites was evaluated using oxy acetylene torch test at low heat flux (125 W/cm2) and high heat flux levels (500 W/cm2). Mass ablation rates have increased at both flux levels marginally up to 2 wt.％ addition of nanoclay beyond which it has increased significantly. This is in contrast to increased thermal stability observed for Type-I and Type-Ⅱ composites up to 2 wt.％addition of nanoclay. Increased ablation rates due to nanoclay addition was attributed to higher insulation effi-ciency of nanolcay, which accumulates more heat energy in limited area behind the ablation front and self-propagating ablation mechanisms triggered by thermal decomposition of organic part of nanoclay.     

Fullerene bisadduct stabilizers: The effect of different addition positions on inhibiting the autocatalytic decomposition of nitrocellulose absorbed nitroglycerin

To explore the effect of different positions and number of pyrrolidine bound to the carbon cage on the stabilization effect of fulleropyrrolidine derivatives to nitrocellulose (NC)/nitroglycerine (NG), we synthesized N-(4-methoxy) phenylpyrrolidine-C₆₀ and four different of bis(N-(4-methoxy) phenylpyrrolidine)-C₆₀ compounds through Prato reaction. Their structures were characterized by UV–vis, ¹H NMR, ¹³C NMR, high-resolution mass spectroscopy, and single-crystal X-ray diffraction. Their stabilization effect to NC/NG were investigated using differential scanning calorimetry, methyl violet, vacuum stabilization effect, weight loss, and accelerating rate calorimeter tests. The results indicated these compounds had excellent stabilization effect to NC/NG. The stabilization effect of the fulleropyrrolidine bisadducts to NC/NG is significantly better than that of fulleropyrrolidine monoadduct and C₆₀. Moreover, the position where pyrrolidine binds to fullerene in fulleropyrrolidine bisadducts is different, and its stabilization effect to NC is also different. The stabilization effect order of different bisadduct isomers to nitrocellulose is as follows: e-edge > trans-2> cis-2> trans-3. Electron paramagnetic resonance (EPR) and FT-IR were used to study the stabilization mechanism of fulleropyrrolidine derivatives to NC/NG. The EPR results also show that fulleropyrrolidine bisadducts with different addition sites have different abilities to absorb nitroxide, and their ability is better than that of the monoadduct and C₆₀, which is consistent with the results of stabilization effect performance test.     

An interface shear damage model of chromium coating/steel substrate under thermal erosion load

The Cr-plated coating inside a gun barrel can effectively improve the barrel's erosion resistance and thus increase the service life.However,due to the cyclic thermal load caused by high-temperature gun-powder,micro-element damage tends to occur within the Cr coating/steel substrate interface,leading to a gradual deterioration in macro-mechanical properties for the material in the related region.In order to mimic this cyclic thermal load and,thereby,study the thermal erosion behavior of the Cr coating on the barrel's inner wall,a laser emitter is utilized in the current study.With the help of in-situ tensile test and finite element simulation results,a shear stress distribution law of the Cr coating/steel substrate and a change law of the interface ultimate shear strength are identified.Studies have shown that the Cr coating/steel substrate interface's ultimate shear strength has a significant weakening effect due to increasing temperature.In this study,the interfacial ultimate shear strength decreases from 2.57 GPa(no erosion)to 1.02 GPa(laser power is 160 W).The data from this experiment is employed to establish a Cr coating/steel substrate interface shear damage model.And this model is used to predict the flaking process of Cr coating by finite element method.The simulation results show that the increase of coating crack spacing and coating thickness will increase the service life of gun barrel.     

基于RTP协议H．264视频流传输QoS保证的研究

提出一个Linux环境下基于RTP/RTCP的H.264视频流传输的方案,在Linux中调用V4L(VideofourLinux)的API函数采集视频流,经X264压缩,RTP/RTCP协议打包进行传输。并通过RTCP的RR(接收方报告)包反馈信息和吞吐量公式来计算近似带宽,以起始帧量化参数start-qp为视频编码的调节参数,由近似带宽来控制视频编码的参数调整,达到控制输出码率的目的,实现对视频传输的QoS(QualityofService)保证。     

一种鱼雷辐射噪声的线谱估计方法

基于鱼雷辐射噪声的物理特性和线谱特征,探讨了一种鱼雷目标特征提取方法。该方法结合经典谱与现代谱估计,提取水下目标辐射噪声线谱特征。通过两次估计采集数据的功率谱,得到估计算法功率谱图,然后分析功率谱图,先确定线谱存在的大致区域,再估计精确线谱。进行仿真研究,得到了较好的效果,证明该方法对低频段的线谱特征提取有很好的实用性。     

三坐标雷达目标真实高度估计算法研究

在目标跟踪领域,通过三坐标雷达的测量值(斜距、仰角及方位角)来估算目标的真实高度一直是个难点。目前主要有两类处理方法:坐标转换法和等效地球半径法。前者把与雷达天线相关的三坐标测量值转换到大地坐标系统来计算目标高度;后者充分考虑地球曲率以及大气折射的特性,通过增加地球半径来估算目标的高度。最后对上述的两类方法进行总结、比较与分析。