火炸药理化实验室危害辨识与防护

火炸药理化分析检测对象是含能材料和火炸药制品,具有燃烧、爆炸的危险性;火炸药自身固有的燃爆危险性,决定了其理化分析的特殊性,必须采取有针对性的防护措施;分析了火炸药理化分析检测过程中存在的危害因素及其产生的途径,并从安全技术和安全管理角度提出了相应的对策措施。     

硝胺单元推进剂燃速的理论计算

在火炸药燃速预估模型的基础上，分析了硝胺单质炸药的热分解特征，提出了硝胺单元推进剂燃烧初期热分解机理的有关假说，并将气相分解产物分类为氧化剂、还原剂、可裂解自由基和惰性基团，进而提出了硝胺单元推进剂燃速和压力指数公式．运用该公式可从化学结构出发计算硝胺单质炸药的燃速和压力指数．通过十种不同类型硝胺单元推进剂燃速的实际计算表明，理论值与实测值十分一致．由此讨论了影响硝胺单质炸药燃速与燃速压力指数的化学结构因素．     

高能推进剂燃烧转爆炸仿真模型研究

为研究高能固体推进剂的安全性能,对某型号发动机燃烧转爆炸试验进行研究,修改了燃烧产物运动的基本方程组,并对燃烧情况作了必要简化,建立了高能推进剂在封闭容器中燃烧转爆炸的仿真模型,预测爆炸前燃烧室内压力随时间的变化情况.给定相关参数,仿真结果与试验结果吻合得很好,燃烧室达最大压力时偏差为0.2MPa.修改参数,该模型也适用于高能推进剂在封闭容器中燃烧的其他情形.     

一种新型热感度实验装置在爆炸物危险性分级中的应用

根据爆炸物危险性分级的需要,设计了一种用于测试火炸药热感度的实验装置。采用该实验装置对几种典型固体炸药进行了实验,结合反恐需要,对几种液体炸药进行了实验测试,并对这些试样进行了危险性分类,最后研究了粒度对样品热效应的影响。研究结果表明:该实验装置具有足够的精度,实验结果准确可靠,可以用来评估物品是否是爆炸性物质。因此,该实验装置可以应用于爆炸品的危险性分级。     

舱室密闭空间中爆炸载荷后燃烧效应数值计算研究

为准确分析梯恩梯炸药在密闭空间中的爆炸载荷,在统一设施标准模型和基于能量守恒的简化计算公式基础上,提出了一种计算爆炸产物后燃烧能量的方法。该方法应用到基于有限元分析软件ANSYS/AUTODYN平台的数值模拟中,实现负氧平衡炸药在密闭空间中爆炸过程的数值仿真计算。计算结果与试验测试结果表明：梯恩梯炸药在密闭空间中发生爆炸时,其爆轰产物的后燃烧效应不可忽视;不考虑爆炸产物的后燃烧效应,数值计算得到的准静态压力较试验值低55%以上,50 ms内冲量较试验值低49%以上;将爆轰产物的后燃烧能量计入后,爆炸压力及冲量时程的计算值与试验值吻合较好,为结构受爆炸载荷响应分析提供了准确的输入载荷。     

用热爆炸临界温度评价火药装药热安全性的试验方法

探索采用热爆炸临界温度(Tcr)评价火药装药热安全性的可行性及合适的试验条件和数据处理方法,研究了双基推进剂和改性双基推进剂的多种尺寸装药的热爆炸试验,获得了装药在一定温度下发生燃烧的延滞期及热爆炸临界温度。结果表明,可用热爆炸临界温度评价双基或改性双基推进剂不同装药体系的热安全性,最佳试样直径为20~25mm。延滞期采用10h和最低爆炸(燃烧)温度与最高不爆炸(燃烧)温度相差5℃的结束试验的假设条件对于双基或改性双基推进剂是合理的。采用lnr(半径)-Tcr拟合外推获得的Tcr值比文献报道的方法获得的Tcr值低。     

凝聚相炸药爆炸过程中二次燃烧现象研究

为考察不同类型炸药爆炸火光现象差异性与炸药本身性能参数之间的相关性,采用分幅式高速摄像设备对17种凝聚相炸药小药量爆炸过程中的二次燃烧现象进行了试验研究.试验结果表明:凝聚相炸药爆炸火球在二次燃烧阶段的发展过程主要由炸药的氧平衡情况决定,而与试验装药密度下的爆压、爆热、爆速等参数相关性不大.用于估算炸药爆炸火球参数的相关公式存在过于简化或不全面的问题.     

考虑后燃烧效应密闭空间内爆炸场数值计算研究

为了研究后燃烧效应对爆炸场参数的影响规律,提出一种考虑后燃烧效应密闭空间内爆炸场数值计算方法,将简化的反应率模型,耦合到三维两组可压缩欧拉方程中近似考虑后燃烧效应。并通过建立气体内能与热容之间的关系求得瞬态温度,根据热力学关系建立绝热指数计算公式。基于FORTRAN平台,采用五阶WENO有限差分格式,自主开发考虑后燃烧效应密闭空间内炸药爆炸场三维数值计算程序。基于所开发的程序数值探讨内爆炸场演化过程及后燃烧效应对爆炸场参数计算的影响。结果表明:(1)准静态温度、绝热指数及超压数值解与考虑后燃烧效应的理论解吻合较好,相对误差小于5%,初步验证了所开发程序的可靠性。(2)后燃烧效应在内爆炸场数值模拟中需要引起足够的重视,同一内爆炸工况下,准静态温度、绝热指数及超压数值解与不考虑后燃烧效应的理论解误差分别高达25%,6%,31%。     

复合固体推进剂静电危险性研究进展

从复合固体推进剂静电危险性实验测试方法、理论预估和静电对推进剂的作用机理等三方面,综述了国内外固体推进剂静电危险性研究的进展。国外使用有关设备测量实际作用于推进剂试样上的静电能量作为静电感度评价标准;"渗透系数"模型可实现对推进剂静电危险性的简单预估,基于热点形成发展的计算模型建立了推进剂的静电危险性与推进剂力学、燃烧性能之间的联系;利用红外测温方法,观察到了静电作用过程中热辐射和热传导,形成了广为接受的"热点"形成机理。国内尚需加强复合固体推进剂静电危险性的系统研究,形成可靠的复合固体推进剂静电危险性评价方法。     

信息动态

纳米铝热剂作为一类高能、钝感的新型含能材料,具有较高的燃烧效率、较快的能量释放速率及较好的安全性能等特点,在火炸药、火箭推进剂等领域有广泛的应用前景.在系统地调研和整理国外最新相关资料的基础上,介绍了国外纳米铝热剂技术的研制现状与技术发展水平.根据目前的发展状况,预测了纳米铝热剂将成为提高火炸药性能与安全性的重要途径.     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.     

Design and Analysis of Test Schemes of Static Postponing Time on Shrapnels Used to Riot Control

The test scheme of static postponing time given in our actual national military test standard on shrapnels used to control riot is a nine-point test scheme on the combined action of three kinds of temperatures and three kinds of pressures,the consumed ammunitions are more excessive. Statistic analysis and tentative checkout about a lot of test data are done,feasibility gists are put forward for optimizing of the test design scheme. The optimizing design and data analysis of test scheme of the item are done by managing uniformity design theory, two scientific and reasonable six-point test schemes are confirmed. The feasibility and reliability of the optimizing design schemes put forward above are proved ulteriorly by test validating. The gained schemes not only have good design uniformity and little ammunition wastage and meet the test demand, but also have better forecast ability for the result data of other points using the mathematic models from the actual test points.     

Design of Non-fragile Satisfactory Estimator for Linear Continuous Perturbed Stochastic Systems

The design problem of non-fragile estimator is addressed for a class of perturbed linear continuous systems. The perturbations occur on the plant and estimator parameters. The estimator designed should force the error system to achieve the desired decay rate and force the steady error variance less than the specified upper bound irrdevancy of the admissible plant perturbations and estimator perturbations. Consistency problem of the decay rate with the variance upper bound is first considered via linear matrix inequality （LMI） approach. The solution of the estimator parameter under specifications to be consistent is then discussed. The consistency condition of specifications and estimator parameter solution are transformed to feasible or minimum problems subject to a set of LMI respectively. The method is illustrated by a numerical example.     

An Improved Scene-based Nonuniformity Correction Algorithm for Infrared Focal Plane Arrays Using Neural Networks

The improved scene-based adaptive nonuniformity correction （NUC） algorithms using a neural network （NNT） approach for infrared image sequences are presented and analyzed. The retlna-like neural networks using steepest descent model was the first proposed infrared focal plane arrays （IRFPA） nonuniformity compensation method, which can perform parameter estimation of the sensors over time on a frame by frame basis. To increase the strength and the robustness of the NNT algorithm and to avoid the presence of ghosting artifacts, some optimization techniques, including momentum term, regularization factor and adaptive learning rate, were executed in the parameter learning process. In this paper, the local median filtering result of Xij （ n ） is proposed as an alternative value of desired network output of neuron Xij （ n ）, denoted as Tij （ n ）, which is the local spatial average of Xij （ n ） in traditional NNT methods. Noticeably, the NUC algorithm is inter-frame adaptive in nature and does not rely on any statistical assumptions on the scene data in the image sequence. Applications of this algorithm to the simulated video sequences and real infrared data taken with PV320 show that the correction results of image sequence are better than that of using original NNT approach, especially for the short-time image sequences （several hundred frames） subjected to the dense impulse noises with a number of dead or saturated pixels.     

Piecewise Filter of Infrared Image Based on Moment Theory

The disadvantages of IR images mostly include high noise, blurry edge and so on. The characteristics make the existent smoothing methods ineffective in preserving edge, To solve this problem, a piecewise moment filter （PMF） is put forward. By using moment and piecewise linear theory, the filter can preserve edge. Based on the statistical model of random noise, a related-coefficient method is presented to estimate the variance of noise. The edge region and model are then detected by the estimated variance. The expectation of first-order derivatives is used in getting the reliable offset of edge. At last, a fast moment filter of double-stair edge model is used to gain the piecewise smoothing results and reduce the calculation. The experimental result shows that the new method has a better capability than other methods in suppressing noise and preserving edge.     

Bistatic Sonar Localization Based on Best Linear Unbiased Estimation

A best linear unbiased estimation （BLUE） algorithm for bistatic sonar localization is proposed. The Cramer-Rao bound for bistatic Sonar and the geometrical dilution of precision （GDOP） in different conditions are given. The simulation results show that the location accuracy of BLUE algorithm is higher than the weighted least square method.     

Research on Gear-broken Fault Diagnosis in a Tank Gearbox

A fault diagnosis method of working position gear in a tank gearbox is put forward based on simulating the fault of working position gear in an actual tank, extracting the envelope of vibration signal by Hilbert transformation amplitude demodulation method, and zooming the low-frequency band to envelope signal.