红磷与纳米氧化铝组合烟幕对10.6μm激光的消光系数研究

为了提高红磷烟幕对10.6μm激光的消光性能,在中型烟幕试验柜中分别测试了纳米氧化铝气溶胶、红磷及其组合烟幕对10.6μm激光的质量消光系数。在空气相对湿度为40%的条件下,纳米氧化铝气溶胶、红磷及其组合烟幕对入射功率为1.0W的10.6μm激光的平均质量消光系数分别为0.222,0.298,0.449m2.g-1。根据试验结果,纳米氧化铝气溶胶和红磷烟幕组合使用后可以显著改善纳米氧化铝粉体的分散特性,并使得红磷烟幕对该波段激光的质量消光系数提高50.7%。     

三维石墨烯粉体制备及其红外消光性能

为了探究三维石墨烯的红外消光性能,采用热化学沉积法制备了三维石墨烯粉体,通过电镜、拉曼光谱仪和X射线衍射仪表征了三维石墨烯粉体的形貌和结构特征,利用粉体综合特性仪测试了其流散性;利用烟幕箱试验测试了三维石墨烯的红外消光性能,并与复合石墨、碳纤维的消光性能进行了比较。结果表明：三维石墨烯的红外消光性能优异,在红外波段为3~5 μm和8~14 μm时,其平均质量消光系数分别约为1.32 m²·g^-1和1.09 m²·g^-1。与复合石墨和碳纤维相比,其在3~5 μm的平均质量消光系数分别提高了57%和132%,其在8~14 μm的平均质量消光系数分别提高了35%和102%,具有更优异的红外消光性能。     

镀镍石墨烯制备及红外干扰性能

为了研究镀镍石墨烯的红外消光性能,探索消光较佳的工艺条件,采用氧化还原和化学镀的方法制备了镀镍石墨烯,通过正交试验设计,以红外衰减率为评价指标,分析了各因素对镀镍石墨烯消光性能的影响,确定了红外消光较佳的工艺条件。利用烟幕箱试验,测试了镀镍石墨烯的红外透过率。基于“Lambert-Beer”定律,通过线性拟合计算了镀镍石墨烯的平均质量消光系数,并与镀前进行了对比分析。结果表明：红外消光较佳的镀镍石墨烯的制备工艺参数为：六水合硫酸镍的浓度为20 g·L^-1,次磷酸钠的浓度为24 g·L^-1,柠檬酸钠的浓度为10 g·L^-1,施镀温度为65 ℃。该条件下制备的镀镍石墨烯在中远红外波段均表现出非常好的红外消光能力。对于3~5 μm和8~14 μm红外波段,镀镍石墨烯的平均质量消光系数分别为2.38 m²·g^-1和2.19 m²·g^-1。与改性前的石墨烯相比,镀镍石墨烯在中远红外波段的平均质量消光系数分别提高了30%和35%,具有更广阔的应用前景。     

碳纳米材料红外图像遮蔽特性研究

碳纳米材料是一种新型材料,具有尺度小、重量轻、导电及吸波性能好等特点.为了探索碳纳米材料在干扰红外成像制导武器方面的应用,利用大型烟幕箱研究了碳纳米管、纳米碳纤维、纳米石墨几种碳纳米材料对8～12 μm波段红外图像的遮蔽特性.结果表明,碳纳米材料对红外辐射由于吸收和散射双重作用,具有很好的远红外消光作用,质量消光系数最小和最大值分别为0.8884 m2·g-1和2.6226 m2·g-1.     

超细HNS颗粒状态研究

研究了温度及高聚物对超细六硝基茋(HNS-Ⅳ)颗粒状态的影响。结果表明:经22~25℃干燥48 h的超细HNS颗粒分散性较好,而100℃干燥2 h即引起HNS-Ⅳ颗粒团聚;HNS-Ⅳ在真空25℃脱气8 h,所测孔体积与比表面积(BET)高于真空65℃脱气2 h的测试数据;HNS-Ⅳ比表面积并非完全取决于平均粒径,而在一定程度上随其孔体积呈线性变化;纯HNS-Ⅳ平均粒径0.789μm,孔体积0.032 cm3.g-1,比表面积15.13 m2.g-1,添加3%P聚合物后,其平均粒径0.594μm,孔体积0.026 cm3.g-1,比表面积11.41 m2.g-1,加入4%P聚合物,其平均粒径0.890μm,孔体积0.052 cm3.g-1,比表面积23.38 m2.g-1。     

纳米镍粉对1.06μm和10.6μm激光的消光性能研究（英）

在容积为20 m3的烟幕箱中测试了30 g纳米镍粉形成的烟幕对1.06μm和10.6μm激光的消光性能。其质量消光系数分别为1.542 m2.g-1、1.078 m2.g-1,沉降速度为1.035×10-3m.s-1,与常规材料的烟幕性能比较表明,纳米镍粉形成的烟幕消光性能好,悬浮时间长,是一种能有效干扰1.06μm和10.6μm激光的新型烟幕材料。     

光谱法研究膨胀石墨红外波段复折射率

具有良好消光性能的膨胀石墨可用作红外/毫米波复合无源干扰材料,复折射率是研究其消光性能的重要参数.采用压片法分别对膨胀石墨压片在0.24～2.6 μm和2.5～25μm波段的反射光谱进行了测试.结合所测光谱数据,利用Kramers-Kronig(K-K)关系和Bruggemen有效介质理论对膨胀石墨5～10μm波段的复...     

Cd1-xZnxS三元系颜料红外性能研究

采用固相反应方法制备名义组成为Cd1-xZnxS三元系半导体颜料。利用X光衍射表征体系的结构,结果表明,最终实验产物均为纤锌矿结构。测试样品的红外吸收光谱以及3～5μm和8～14μm双波段红外发射率,研究Cd/Zn配比对光谱特性的影响,探讨发射率随波长、配比及温度的变化而改变的机理。     

红磷烟幕使用特性及其对红外激光的最佳消光直径

在中型烟幕柜中测试了红磷烟幕的粒度分布,计算了红磷烟幕的发烟能力和自由沉降速度以及对多种波长电磁波的衰减系数,分析了红磷烟幕的多波段消光特性及其在组合烟幕中的应用。研究表明：红磷烟幕平均直径分布在0.5～13μm;发烟能力3.9—22.9;对可见光至14μm红外的衰减系数分布在200／m～41.67/m;沉降速度远小于0.007 m/s并具有良好的组合使用特性。根据Mie理论计算了多种直径红磷烟幕粒子对1.06 μm、3.39 μm和10.6 μm激光的散射、吸收和消光效率因子。分析表明：直径显著小于入射波长的烟幕粒子的消光作用中吸收效应居主导地位;随着粒子直径增大散射效应逐渐增强;当烟幕粒子的尺度接近入射波长时散射和吸收效应趋于一致;红磷烟幕粒子对10.6μm和3.39弘m红外激光辐射的最佳消光直径分别为9.0μm和4.0μm.     

膨胀石墨烟幕对1.06μm和10.6μm激光的消光特性研究

为测试膨胀石墨烟幕红外激光消光特性,在分析膨胀石墨烟幕消光机理的基础上,通过测量其在不同时段的烟幕平均质量浓度和平均激光透过率,得到了膨胀石墨烟幕对1.06μm近红外和10.6μm远红外激光的质量消光系数分别为1.149 8m<'2>/g和0.820 5m<'2>/g.结果表明,膨胀石墨烟幕对两个波长的红外激光具有良好的消光和干扰效果,在光电对抗领域具有广阔的应用前景.     

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.