瞬态电压抑制二极管对半导体桥换能元电爆特性影响的模拟

为了解决瞬态电压抑制二极管(TVS)用于半导体桥火工品抗静电设计的参数优化问题,采用电路模拟和试验相结合的方法,构建了电容放电发火测试电路等效模型和半导体桥PSpice电子器件模型,研究了TVS参数对半导体桥换能元电爆特性的影响。结果表明,当钽电容等效串联电阻为288 mΩ,钽电容等效串联电感为0.68μH,导线电感为40 nH和回路电阻为3.3 mΩ时,22μF/16 V电容放电发火电路的等效电路模型和实际吻合。以阻抗-能量列表模型的方式创建的半导体桥PSpice电子器件模型模拟曲线和实际曲线吻合,且模拟电爆数据偏差小于3%。模拟和试验结果表明,TVS对半导体桥电爆性能的影响程度随着其击穿电压的升高而降低。当TVS的击穿电压在8～12 V之间时,即使TVS击穿电压低于半导体桥发火电压,半导体桥仍能正常爆发,TVS击穿造成的分流导致半导体桥爆发延迟(2μs),且延迟时间随着TVS击穿电压的降低而延长。     

压敏电阻对半导体桥火工品电爆性能的影响

压敏电阻能有效抑制浪涌电压,可用于火工品电磁防护。为研究压敏电阻对半导体桥(SCB)火工品电爆性能的影响,本研究在电容放电(47μF、22 V)与恒流(100 ms)激励条件下测试了并联压敏电阻前后典型尺寸SCB火工品100μm(L)×400μm(W)×2μm(T)和低发火能量SCB火工品20μm(L)×100μm(W)×2μm(T)的爆发时间和爆发消耗能量的变化规律。电容放电实验(47μF、22 V)结果 t检验表明,并联压敏电阻前后的典型SCB火工品的爆发时间和爆发能量均无显著性变化;对于低发火能量SCB火工品,并联击穿电压较低的压敏电阻时,爆发所需能量升高14%,而爆发时间无显著性变化。而恒流(100 ms)激励实验结果表明,压敏电阻对两种SCB火工品电爆性能均无显著性影响。     

温度对半导体桥电爆性能影响初探

为了研究温度对半导体桥（SCB）电爆和点火的影响,采用电容放电激励的方式,研究了SCB在环境温度分别为25℃和-40℃的电爆特性,建立数学模型并探讨了环境温度对SCB电爆的影响;开展了以Al/CuO纳米铝热剂为点火药剂的SCB点火感度实验,在环境温度为25℃和-40℃测试了Al/CuO纳米铝热剂的点火温度,并采用Neyer D最优化法测试SCB点火感度。结果发现,当充电电压由30 V增加至50 V时,电爆延迟时间差值由0.47μs降低至0.25μs,电爆所需能量的差值由0.16 mJ增加至0.65 mJ,表明随着充电电压的增加,环境温度对电爆延迟时间的影响减小,对电爆所需能量的影响增大;并发现不同温度下Al/CuO纳米铝热剂点火温度没有显著差异,为740.7℃;-40℃时的SCB临界发火电压比25℃时高0.6 V。     

复合半导体桥的电爆特性

针对半导体桥小型化带来的点火可靠性问题,制备了复合半导体桥,采用高速存贮示波器对其在22μF电容不同充电电压下的电爆过程进行了研究,并与多晶硅半导体桥的电爆性能进行了对比。结果显示:在电爆过程爆发前,复合半导体桥和多晶硅半导体桥的电爆过程基本一致;爆发后特别是在高压时(50 V),与多晶硅半导体桥相比,复合半导体桥上电流下降缓慢,爆发所需时间稍偏长,作用于等离子体上的能量稍多;爆发后3μs内,复合半导体桥作用于等离子体上的能量增加较多,因此复合半导体桥点火可靠性更高。复合半导体桥上金属薄膜的存在是造成上述结果差异的原因。     

半导体桥对含能材料的点火特性研究

在10μF钽电容放电激励下,对两种阻值相当质量不同的半导体桥(SCB)和细化的发火药剂斯蒂芬酸铅(LTNR)和叠氮化铅(PbN6)所组成的发火件进行了实验研究,根据发火件的电特性变化和发火现象发现半导体桥存在电热发火、电爆发火和等离子体发火三种情况,测试了SCB/LTNR和SCB/PbN6发火件的50%发火电压和发火时间。结果表明半导体桥的发火电压阈值不仅与发火药剂有关,还与半导体桥换能元有关,所以半导体桥的设计存在最佳质量,通过对比得知LTNR比PbN6感度高,PbN6比LTNR的燃速高。     

微型半导体桥电容抗静电加固技术研究

针对微型半导体桥在强静电放电脉冲作用下可能出现损伤,从而导致半导体桥火工品早爆、误爆、可靠性降低等问题,研究了微型半导体桥在不同强度静电电压作用下的桥区损伤以及电阻变化情况,分析了静电电压强度与桥区损伤面积以及电阻变化之间的关系,并采用抗静电电容对微型半导体桥进行了抗静电加固以及性能实验.实验结果表明,半导体桥并联电容后抗静电能力增强,半导体桥桥区未出现损伤,药剂完好无损,但发火电压随电容值的增大而增大,作用时间随电容值的增大而变长,可根据具体半导体桥选择合适的并联电容.     

降低半导体桥/斯蒂芬酸铅发火能量的技术途径研究

进一步降低半导体桥（SCB）换能元件发火能量是微机电系统（MEMS）引信用微型起爆系统发展的瓶颈技术。通过发火感度试验,获得了减小桥区尺寸、增加V型缺口、适当长宽比、降低药剂粒度等是降低SCB发火能量的有效技术途径。在试验方案范围内获得最小全发火电压3.83 V,发火能量0.073 mJ,最大不发火电流229.88 mA. 分析发火现象和电特性曲线得出：SCB换能元的桥区面积7.65×10² μm²,质量3.55×10^-6 mg,临界发火属于电热发火;桥区面积5.68×10² μm², 质量2.64×10^-6 mg,临界发火属于电爆发火。进一步降低半导体桥（SCB）换能元件发火能量是微机电系统（MEMS）引信用微型起爆系统发展的瓶颈技术。通过发火感度试验,获得了减小桥区尺寸、增加V型缺口、适当长宽比、降低药剂粒度等是降低SCB发火能量的有效技术途径。在试验方案范围内获得最小全发火电压3.83 V,发火能量0.073 mJ,最大不发火电流229.88 mA. 分析发火现象和电特性曲线得出：SCB换能元的桥区面积7.65×10² μm²,质量3.55×10^-6 mg,临界发火属于电热发火;桥区面积5.68×10² μm², 质量2.64×10^-6 mg,临界发火属于电爆发火。     

不同掺杂元素对 SCB 电爆特性的影响

为研究不同掺杂元素对半导体桥电爆特性的影响规律,利用电容放电发火系统,对硼掺杂SCB和磷掺杂SCB的临界发火电压、发火时间以及发火所消耗的能量进行了测试,并做了对比分析。结果表明:在尺寸相同、掺杂浓度相同的条件下,磷掺杂半导体桥比硼掺杂半导体桥临界发火电压低;相同发火电压下,掺杂元素对发火时间的影响较小,并且磷掺杂半导体桥的发火能量比硼掺杂半导体桥的高,说明磷掺杂SCB性能优于硼掺杂SCB。     

负温度系数热敏电阻对半导体桥电爆性能影响

温度是影响火工品电磁防护其防护效果的主要因素,负温度系数(NTC)热敏电阻用于半导体桥(SCB)能有效提高其射频感度。采用恒流激励和电容放电两种实验,对不同环境温度下NTC热敏电阻对SCB性能的影响规律进行了研究。通过1 A 5 min恒流激励实验,分析了室温(25℃)和高温(70℃)时NTC热敏电阻的并联分流情况;25℃时NTC热敏电阻分走59%回路电流,70℃时,对小尺寸SCB(S-SCB)的分流率最大达到63%。在电容放电激励下,探讨了并联NTC热敏电阻SCB在25℃和70℃时电爆性能的变化情况。结果表明,并联NTC热敏电阻前后,典型尺寸(L-SCB)在25℃和70℃下的爆发时间和爆发消耗能量均无显著性变化。而S-SCB并联NTC热敏电阻后,当温度从25℃升至70℃,爆发时间从5.94μs增长到7.18μs,爆发消耗积分能量从0.388 m J降低到0.178 m J。     

半导体桥爆发临界性实验研究

对电容放电和5min恒流激励时半导体桥换能元的爆发特性进行了实验研究,测试了半导体桥作用过程中电压、电流、电阻的变化规律,通过对电阻变化特点的详细分析,发现恒流激励时半导体桥存在临界爆发电流,电容放电激励时存在爆发和产生等离子体两个临界电压。然后利用D-最优化法测试了电阻约为0.8Ω、长度为80μm、宽度为380μm、厚度为2μm、V型角为90°的半导体桥的临界爆发电流、临界爆发电压和产生等离子体的临界电离电压等数据,通过加载不同的电压,得出了爆发时间与充电电压之间的规律。     

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.     

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.     

Parameter Identification for the Valve Control Cylinder System of a Hydraulic Manipulator

In mechanical, hydraulic and electronic systems, the determination of system parameters is often challenging because liquid parameters often change significantly, due to variations in working and environmental conditions. Therefore, it is of significant practical importance to identify those parameters through experimental procedures. A systematic approach to identifying parameters in the valve controlling cylinder system of hydraulic manipulators is provided. It first derives the transfer function of the system, and then uses P control of PID control to predict system parameters. The predicted parameters are further validated using PID control. The prediction through simulation using MatLab language is utilized, which agrees well with experimental results.     

Three-dimensional Numerical Simulation of Combustion Field in the Combustion Chamber

In order to study the effect of rotation on the combustion in the underwater vehicle, a two-phase turbulent combustion process is described with Reynolds stress turbulence model, eddy-dissipation turbulent combustion model, P-1 radiation model and particle tracking model of liquid. The flow in the rotating combustion chamber is simulated at two different working speeds, 0 r/min and 1 000 r/min by Fluent software. The temperature, gas velocity, static pressure of wall and fuel concentration are computed and compared. The results show that the combustion in rotating combustor is faster and more effective.     

Software Communication Architecture Implementation and Its Waveform Application

This paper attempts to do a research on the development of software defined radio（SDR） based on software communication architecture（SCA）. Firstly, SCA is studied and a whole reference model of SCA3.0 core framework （CF） is realized; Secondly, an application-specific FM3TR waveform is implemented on the platform of common software based on the reference model; Thirdly, from the point of view of real-time performance and software reuse, tests and validations are made on the above realized CF reference model and FM3TR waveform. As a result, the SCA-compliant SDR has favorable interoperability and software portability and can satisfy the real-time performance requirements which are not too rigorous.     

Dynamic Simulation of the Tank Gun Recoil Response

By using the ATV module of MSC. ADAMS, the dynamic simulation of recoil response of tank gun is analyzed.How the recoil force affects the bodywork and the suspension during gun firing, as well as the changing status of the gun muzzle‘s velocity are gained. All results and analyzing methods are offered for the designing basis of optimizing tank vehicle-gun match. The constructive exploration is beneficial to improving the general capability of tank.     

Survey of Controllable Suspension System for Off-road Vehicles

The controllable suspension system can improve the performances of off-road vehicles both on road and cross-country. So far, four controllable suspensions, that is, body height control, active, semi-active and slow-active suspensions, have been developed. For off-road vehicles, the slow-active suspension and the semi-active suspension which have controllable stiffness, damping and body height are more appropriate to use. For many years, some control methodologies for controllable suspension systems have been developed along with the development of modern control theory, and two or more original control methods are integrated as a new control method. Today, for military or civilian off-road vehicles, the R&D of controllable suspension systems is ongoing.     

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.