Al-LiH复合燃料制备及性能

为了提高铝粉燃烧效率,利用球磨法分别制备了质量含量为3%,5%,10%,15%的Al-LiH复合燃料。通过X射线衍射仪(XRD)、扫描电镜(SEM)、粒度仪对样品结构、形貌和粒径进行表征;采用差热-热重量热仪对其热氧化性能进行表征,最后采用CO₂激光点火装置、高速摄像机及氧弹量热仪对其燃烧性能进行考察。结果表明：通过球磨法可以将LiH嵌入Al粉内部,LiH含量是影响其微观形貌及粒径、粒径分布的关键因素,LiH的加入使得燃料质量热值增加,同时随着LiH含量的增加Al-LiH复合燃料燃烧火焰强度增强,点火延迟时间大幅降低。其中由于Al-LiH复合燃料在高温下发生了微爆现象,Al-3LiH和Al-10LiH复合燃料在一次氧化后分别实现第二次氧化。     

铝基微单元复合燃料在NEPE固体推进剂中的应用

为研究铝基微单元燃料在硝酸酯增塑聚醚（NEPE）固体推进剂中的应用性能,以自制的铝基微单元复合燃料（Al@AP）代替铝粉加入NEPE固体推进剂,以真空定容爆热试验、发动机试验、残渣活性铝测试、高速摄影、单向拉伸试验、工艺性能测试等手段研究了Al@AP对NEPE固体推进剂燃烧、力学、工艺等性能的影响;并对Al@AP在NEPE固体推进剂中的燃烧作用机理进行了分析。结果表明,以19.5%的Al@AP代替FLQT-3 Al后,NEPE固体推进剂的爆热由6039.4 J·g^-1提升至6924.8 J·g^-1,残渣量由28.91 g降至7.64 g,残渣活性铝含量由14.64%降至0.37%,残渣粒径d₅₀由94.12 μm降至24.21 μm,NEPE固体推进剂喷射效率提升,铝粉在燃面停留时间由55 ms缩短至40 ms,且无明显融联团聚现象,且Al@AP对推进剂的燃速、力学、工艺等性能基本无影响。     

固体推进剂中铝粉的燃烧行为

铝粉在固体推进剂燃烧环境中有燃面凝聚现象。铝凝团大小影响着铝粉的燃烧效率和发动机工作性能。铝粉凝团小,燃烧效率就高。推进剂配方和发动机工作状态对凝团大小有决定性影响。通过合理设计推进剂配方和发动机工作状态,可以控制凝团尺寸,进而提高铝粉的燃烧效率和发动机工作性能。     

铝基水反应活性材料制备及其性能研究

为提高铝粉与海水的反应效率和速率,在惰性氛围下,采用高能球磨法通过多次变速循环工艺制备得到了铝基水反应活性材料。通过扫描电子显微镜、热重分析仪、比表面测试等分析表征材料的微观结构和氧化性能;采用自主设计的金属/水反应装置,实时记录铝基水反应金属材料与海水反应产生的氢气量,研究铝基水反应活性材料的活性。研究结果表明：高能球磨能提高铝基材料与海水的反应活性,铝粉经过球磨后反应效率达到原先的2倍;球磨过程中添加剂铋的添加能进一步提高铝基水反应材料的活性;反应总产率能够达到71.2%,其快速期氢气产生反应速率为210.7 mL/(min·g)。制备的铝基水反应活性材料在高能水反应金属燃料推进剂和制氢领域都具有应用价值。     

镁铝金属粉对含硼富燃推进剂燃烧性能及硼氧化效率的影响

为了确定镁铝金属粉对含硼富燃推进剂燃烧性能和硼氧化效率的影响,用靶线法测定三种配方含硼富燃推进剂在0.5,1.0,1.5 MPa三种压力条件下的燃速,采集相应的燃烧残渣,用化学分析法测定了三氧化二硼(B2O3)和总硼(B)含量,计算出硼的氧化效率。实验结果表明,镁粉含量对推进剂燃烧性能有明显影响。推进剂中B的含量为30%,并固定其他组分,金属粉含量为6%,改变镁粉和铝粉比例,镁粉0%,3%,6%,相应铝粉为6%,3%,0%。当镁粉含量较高时,推进剂燃速较高,压力指数也较高;镁粉含量低时,燃烧残渣中B2O3含量较高,而镁粉含量高时,燃烧残渣中B2O3含量较低;且随着压力的增高,残渣中B2O3的含量降低;硼的氧化效率随镁含量的增高和压力升高而降低。镁粉可抑制硼的氧化反应,使硼氧化效率降低,提高推进剂燃速和压力指数。     

超细铝粉对NEPE推进剂燃烧性能的影响

采用多种实验技术研究了级配铝粉（含超细）在NEPE推进剂中的燃烧特性，实验结果表明采用含超细的级配铝粉可以有效地改善NEPE推进剂的燃烧性能，提高铝燃烧效率。其原因在于超细铝粉有不同于普通铝粉的燃烧与热化学行为，它倾向于单颗粒燃烧，并且能大幅度提高推进剂热分解放热量。     

铝/改性氟橡胶复合燃料的制备及应用

为提高铝粉的燃烧效率,以自制的硅烷改性氟橡胶(FKM-GW)为包覆剂,采用溶胶凝胶法,制备了铝/改性氟橡胶复合燃料(FKM-GW@Al),研究了FKM-GW@Al在溶剂中的稳定性,以及不同氟含量的FKM-GW@Al对NEPE高能低燃速固体推进剂的影响.通过DSC-TG研究了FKM-GW@Al以及含FKM-GW@Al的推进剂的热分解性能,分析了FKM-GW@Al对推进剂燃烧性能的影响机制.结果表明具有功能性基团的FKM-GW@Al不易脱覆,在乙酸乙酯中的稳定性较强.与纯Al粉相比,含氟(质量分数)2.58％的FKM-GW@Al,使推进剂的爆热由6348.8 J·g-1提高至6831.6 J·g-1,残渣活性铝含量由1.02％降至0.06％,推进剂的静态燃速和动态燃速均降低.     

Al/HTPB含能复合粒子的制备及表征

为保护铝粉在固体火箭推进剂中的活性,增加超细铝粉与固体推进剂其它组分的相容性,以端羟基聚丁二烯(HTPB)为包覆剂,异佛尔酮二异氰酸酯(IPDI)为固化剂,包覆了表面活化、粒径为2 μm左右的超细铝粉,制备了Al/HTPB含能复合粒子。研究了氨基硅烷偶联剂KH-550改性铝粉及包覆剂用量对包覆铝粉形貌和粒径的影响。用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、红外光谱(FTIR)、激光粒度仪、热重-差热分析(TG-DTA) 表征了 Al/HTPB复合粒子。结果表明:超细铝粉经KH-550改性且包覆剂用量为1.5%时,Al/HTPB含能复合粒子的包覆膜更均匀,低于400 ℃时,HTPB包覆层能防止铝粉的氧化,在400～525 ℃范围内HTPB能迅速燃烧,迅速释放出包覆的活性铝。     

铝粉形态对低燃速丁羟推进剂燃烧性能的影响

通过静态燃烧性能测试及φ１１２ｎｍ发动机动态评定等实验方法,研究了球形铝粉及非球形铝粉对低燃速丁羟推进剂燃烧性能的影响。结果发现,含球形铝粉推进剂的燃速和燃速压强指数略高于含非球形铝粉的推进剂,而且其燃速可通过调节氧化剂的粒度级配来改变,而燃速温度敏感系数没有显著变化。     

燃料组分对含硼富燃料推进剂一次燃烧性能的影响

对含不同金属添加剂(镁、铝及镁铝合金)、不同硼粉粒度及硼粉含量的含硼富燃料推进剂分别进行了爆热(Qv)、燃烧温度(Tf)和成气率(η)测试,对比研究了金属组分对含硼富燃料推进剂燃烧性能的影响。结果表明:镁比铝能提高含硼富燃料推进剂的爆热值、燃烧温度和成气率;镁铝合金比镁更能降低含硼富燃料推进剂爆热及燃烧温度,且提高推进剂燃烧的成气率;当硼粉粒度较粗或较细时,含硼富燃料推进剂的爆热及燃烧温度均较高,而成气率较低,硼粉粒度适中时,推进剂的爆热值及燃烧温度均较低,而成气率较高;硼粉含量增大(氧化剂AP的含量减小),含硼富燃料推进剂的爆热、成气率均降低,而燃烧温度升高。     

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.