弧厚偏差对发射药燃烧残渣形成的影响

为研究弧厚尺寸偏差对发射药燃烧残渣形成的影响规律,采用螺旋测微仪量取球扁形发射药弧厚值,并经统计分析得到发射药的弧厚分布规律。利用混合装药形状函数的形式,将弧厚分布规律转化为装药形状函数,再结合经典内弹道模型,模拟研究发射药弧厚偏差与燃烧残渣之间的关系。结果表明:发射药弧厚存在偏差,弧厚值呈正态函数分布,弧厚较大的发射药难以在膛内燃尽将形成燃烧残渣。其中,研究采用的球扁形发射药弧厚偏差为0.10 mm,射击时将有0.2%的发射药不能燃尽形成燃烧残渣;弧厚偏差Δ0.02 mm或期望值μ≥0.29 mm时,射击时会有部分发射药不能燃尽而形成燃烧残渣,并且随着弧厚偏差的增大或期望值的提高,燃烧残渣量增加。     

37孔硝基胍发射药单一装药和混合装药的燃烧性能

为了解37孔硝基胍发射药单一装药和混合装药的定容燃烧性能,采用花边形37孔三胍-15发射药为主装药(MC),花边形19孔三胍-15包覆药为辅助装药(B)。通过定容密闭爆发器实验,装填密度为0.20 g·cm-3,在高温(50℃)、常温(20℃)、低温(-40℃)条件下,研究弧厚对单一主装药燃烧性能的影响以及混合比例对混合装药(MC+B)燃烧性能的影响。结果表明,随温度降低,37孔单一主装药侵蚀燃烧现象越明显,燃烧渐增性越弱,而相同温度下,弧厚越大的主装药,其侵蚀燃烧现象越不明显,燃烧渐增性越强;温度越高,同一混合比例的混合装药ΔL、Lm/L0值越大,燃烧渐增性越好;相同温度下,混合装药的燃烧渐增性均强于单一主装药,且随着包覆药比例增加,侵蚀燃烧峰逐渐减小,说明包覆药的加入明显地提高了混合装药的渐增性并降低了侵蚀燃烧峰,且在50,20,-40℃条件下,混合装药获得较佳燃烧渐增性的混合比例均为7∶3。     

四孔长方体发射药的形状函数计算及燃烧性能

为研究四孔长方体发射药的燃烧性能,根据四孔长方体发射药的结构特征,建立四孔长方体发射药的燃烧物理模型,通过Maple软件得到其Ψ-Ζ、Γ-Ψ曲线。对比分析了相同弧厚及长宽比时,圆柱七孔发射药、圆柱单孔发射药与四孔长方体发射药的理论燃烧性能,同时研究了不同内外弧厚、长宽比及内孔径大小的四孔长方体发射药燃烧性能,并对其中的一种情况进行了实验验证。结果表明当长宽比大于1.5时,四孔长方体发射药具有良好地燃烧渐增性,且优于圆柱单孔发射药,劣于圆柱七孔发射药,但其分裂点相对于圆柱七孔发射药更加靠后;内外弧厚一致、长宽比为1.5～3、孔径为0.10～0.20 mm的四孔长方体发射药,具有相对较好的燃烧性能;实验结果能够较好地与理论分析结果相吻合,但由于发射药内孔位置的偏离以及尺寸一致性差,导致燃烧分裂点相比于理论计算要提前到达,因此可基于理论分析结果优化加工工艺,提高发射药的尺寸一致性及药孔分布的均匀性。     

侵蚀燃烧在发射装药内弹道中的应用研究

侵蚀燃烧是具有内孔燃烧火药的一种普遍现象，应用侵蚀燃烧可改变火药燃烧的规律。由于火炮发射装药装填密度的变化，不同装填密度发射药所受的内孔与外部压力也不同，这种压力差使发射药内孔在火炮膛内燃烧时发生侵蚀燃烧。利用发射药内孔燃气流动的流速、传热和冲刷对燃速的影响，研究了火炮发射装药的侵蚀燃烧对发射药燃速的影响，建立了发射装药侵蚀燃烧数学模型，分析了发射药装填密度、内孔的孔径、药粒长度等变化所引起的侵蚀燃烧变化及对发射装药内弹道性能的影响。提出了在变装药中，利用侵蚀燃烧提高小装药量、小射程用发射装药膛压的方法。     

表面微孔结构三基发射药的性能

为了调节发射药的燃气释放规律,采用溶解法制备了表面微孔结构三基发射药,利用扫描电镜观察了发射药样品的微观结构;通过密闭爆发器试验研究了其静态燃烧性能;用材料试验机及冲击试验测定了其力学性能;以155 mm火炮研究了发射药的内弹道性能。研究结果表明,与原药相比,表面微孔结构三基发射药燃烧压力上升快,常温下燃烧结束时间缩短3.2 ms;初始动态活度值高,燃烧渐增性比原药低;在点火燃烧初始阶段表观燃速变大,后期燃速与原药基本一致;表面微孔结构三基发射药的力学性能有较小幅度的降低,其中,常温下降低幅度最大,抗压强度和抗冲击强度分别降低了2.98 MPa和0.35 kJ·m-2;减装药炮口初速提高13.9 m·s-1、全装药炮口初速提高15.0 m·s-1,膛压均有不同程度降低。     

药型尺寸对变燃速发射药燃烧渐增性的影响

采用经典密闭爆发器的方法,研究变燃速发射药的药型尺寸与燃烧渐增性的关系。分析了不同配方、药型尺寸变燃速发射药的燃烧实验p-t曲线、L-B曲线特征,得出了配方、药型尺寸对变燃速发射药的燃烧性能影响规律。研究结果表明:在变燃速发射药内外层配方和层厚度确定时,长径比对燃烧渐增性的影响较为明显,发射药药粒长径比越大,燃烧渐增性越好;对双层结构的变燃速发射药,在一定长径比范围内(1.5/1~2.0/1)适当增加阻燃层中高分子含量有利于改善燃烧渐增性。     

一种低烧蚀高渐增性发射药的研究

采用“浸渍-钝感”工艺制得改性单基发射药.用烧蚀管试验表征了该发射药的烧蚀.采用密闭爆发器研究了该发射药的静态燃烧性能,以857-30 mm制式弹道炮研究了发射药在膛内的动态内弹道性能.结果发现,与制式单基发射药相比较,制得的改性单基发射药的烧蚀量降低了16.4％,燃烧渐增因子P,由0.035提高到0.445,初速从8...     

高燃点发射药作为无壳弹装药的可行性分析

通过大量的实验研究，对高燃点发射药的配方、能量、耐热性能、燃烧性能、烧蚀性能以及弹道性能进行了分析，提出了高燃点发射药作为无壳弹装药的可行性意见。由惰性粘结剂、增塑剂和HMX组成的高燃点发射药能量略高于单基发射药，而爆温低于单基发射药；通过HMX固体颗粒尺寸和形状的控制，可使燃速压力指数控制在1．1左右；高燃点发射药的耐热性能通过在350℃下抗自燃模拟时间和爆发温度点试验，其结果明显优于单基发射药，烧蚀小于单基发射药；通过无壳弹装药弹道试验，其点火正常、燃烧安全、膛内没有留膛现象。GRDH高燃点发射药综合性能可满足无壳弹装药的要求。     

封端面内孔阻塞装药气体生成规律的研究

分析了封端面内孔阻塞装药与制式装药燃烧的差异，提出了调整封端面内孔阻塞装药气体生成量的三种途径，研究了封端面内孔阻塞火药的燃烧增面性。结果表明，其增面效果优于１９孔制式装药和按序开裂杜状装药。     

点火药量对发射药燃烧性能的影响

以硝化棉（NC）为点火药,装药密度为0．12 g／cm3,编号为1＃、2＃、3＃、4＃4种发射药为研究对象,采用密闭爆发器实验测试方法,研究点火压力的改变对发射药燃烧性能的影响。研究表明：随着点火压力的升高,发射药的点火延迟期和燃烧时间均缩短;点火压力越高,基于L－B曲线的燃烧渐增性也更好;4种发射药基于ψ－I／I′K曲线的燃烧渐增性强弱顺序为4＃＞1＃＞2＃＞3＃。     

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.     

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.     

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.     

Expert Systems Aimed at General Design of Projectiles

Expert systems aimed at the general design of projectiles can implement a series of intelligent designs, such as the design of HE shell, the scheme expounded and proved, the emulation analysis and calculation, etc. Aiming at the product design feature, the expert system adopts the object-oriented knowledge representation and all kinds of inference control engines to describe and reason the relevant knowledge regarding the product through the microcomputer. It embodies the foundation of emulation analysis and simulated manufacturing of the shell. It makes use of the method that knowledge expression is combined with condition of inference to carry out the overall design and emulation and reference.The paper gives the ways through which the functions can be achieved, gives the modularization of reference and the design methods of systematization, puts forward the method of knowledge expression and working interface, and supplies a platform for similar products of the shell category that can be quickly designed.     

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.