Effects of nano-sized aluminum on detonation characteristics and metal acceleration for RDX-based aluminized explosive

Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same time.However,the near-detonation zone effects of reaction between Nano-Al with detonation products remain unclear.In this study,the overall reaction process of 170 nm Al with RDX explosive and its effect on detonation characteristics,detonation reaction zone,and the metal acceleration ability were comprehensively investigated through a variety of experiments such as the detonation velocity test,detonation pressure test,explosive/window interface velocity test and confined plate push test using high-resolution laser interferometry.Lithium fluoride(LiF),which has an inert behavior during the explosion,was used as a control to compare the contribution of the reaction of aluminum.A thermochemical approach that took into account the reactivity of aluminum and ensuing detonation products was adopted to calculate the additional energy release by afterburn.Combining the numerical simulations based on the calculated afterburn energy and experimental results,the param-eters in the detonation equation of state describing the Nano-Al reaction characteristics were calibrated.This study found that when the 170 nm Al content is from 0％to 15％,every 5％increase of aluminum resulted in about a 1.3％decrease in detonation velocity.Manganin pressure gauge measurement showed no significant enhancement in detonation pressure.The detonation reaction time and reaction zone length of RDX/Al/wax/80/15/5 explosive is 64 ns and 0.47 mm,which is respectively 14％and 8％higher than that of RDX/wax/95/5 explosive(57 ns and 0.39 mm).Explosive/window interface velocity curves show that 170 nm Al mainly reacted with the RDX detonation products after the detonation front.For the recording time of about 10 μs throughout the plate push test duration,the maximum plate velocity and plate acceleration time accelerated by RDX/Al/wax/80/15/5 explosive is 12％and 2.9 μs higher than that of RDX/LiF/wax/80/15/5,respectively,indicating that the aluminum reaction energy significantly increased the metal acceleration time and ability of the explosive.Numerical simulations with JWLM explosive equation of state show that when the detonation products expanded to 2 times the initial volume,over 80％of the aluminum had reacted,implying very high reactivity.These results are significant in attaining a clear understanding of the reaction mechanism of Nano-Al in the development of aluminized explosives.     

激光防空武器系统作战效能研究

激光防空武器系统是一种新型的高技术多指标综合武器系统,其作战效能评估即是研究新型武器系统装备的主要依据,又是一件十分艰难的任务。依据WSEIAC提出的效能分析模型,建立了激光防空武器系统的ADC模型,对激光防空武器系统的作战效能作了研究,对其他武器的效能分析具有示范和借鉴作用。     

未来光电精确寻的制导技术发展前景预测

精确自寻的制导系统是精确制导武器中最重要的组成部分。精确寻的制导系统的性能直接影响武器的作战性能、应用范围和成本。分析了未来高技术战争对精确制导武器发展的要求,探索了21世纪光电精确寻的制导技术的发展趋势,分析了新的精确制导体制应具备的发展特点,并对未来的发展提出了建议和意见。     

冠脉搭桥术用 CO2 激光低能输出方法研究

弱ＣＯ_２激光能量的输出及控制是ＣＯ_２激光冠脉搭桥术的核心技术之一。本文介绍了一种利用普通医用ＣＯ_２激光器获得弱激光能量输出的技术与方法。该方法具有激光输出功率稳定,并可调、输出光斑上能量密度均匀,光斑大小可控的特点,它很好地满足了搭桥仪对激光输出参数的要求;该方法还可应用于其它弱ＣＯ_２激光医疗仪器中。文中对设计原理进行了分析,并给出了设计实例。     

激光测距系统控制策略研究的一种新方法

首先运用更新理论研究了激光测距系统漏测点的分布规律,在该系统跟踪目标的角误差为平稳高斯过程的前提下,给出了易于计算的漏测点分布律的显式表示,为求取使不可补漏测点出现概率最小的控制策略提供了一条行之有效的新途径。     

战术防空激光武器发展概况

空中攻击与防空作战在相互斗争中发展,随着空中威胁目标种类变化、性能提高,作为防空武器的一个重要的新型分支,防空激光武器在快速发展,将在近程防空与反导中起重要作用。综述了空中威胁变化对激光武器的需求,激光武器的分类、组成与特点,以及国外战术防空激光反导武器系统发展概况。     

基于粒子群优化的点云场景拼接算法

多视点三维点点云场景拼接是解决激光三维主动成像目标自遮挡或被遮挡情况下目标数据不完全问题的一种有效方法,它将直接影响到后续的目标检测与识别处理。本文提出了一种基于粒子群优化（PSO）的点云拼接算法,该方法通过投影分布熵对待拼接场景姿态进行估计,由此获取场景拼接的初值,然后利用PSO实现多视点场景的精确拼接。仿真实验结果表明,本文方法是一种有效可行的方法。     

Influence of yttrium on microstructure and properties of Ni–Al alloy coatings prepared by laser cladding

Ni–Al alloy coatings with different Y additions are prepared on 45^# medium steel by laser cladding. The influence of Y contents on the microstructure and properties of Ni–Al alloy coatings is investigated using X-ray diffraction, scanning electron microscopy, electron probe microanalyzer, Vickers hardness tester, friction wear testing machine, and thermal analyzer. The results show that the cladding layers are mainly composed of NiAl dendrites, and the dendrites are gradually refined with the increase in Y additions. The purification effect of Y can effectively prevent Al₂O₃ oxide from forming. However, when the atomic percent of Y addition exceeds 1.5%, the extra Y addition will react with O to form Y₂O₃ oxide, even to form Al₅Y₃O₁₂ oxide, depending on the amount of Y added. The Y addition in a range of 1.5–3.5 at.% reduces the hardness and anti-attrition of cladding layer, but improves obviously its wear and oxidation resistances.     

某高性能激光测距机总体设计与分析

针对某型激光测距机的高性能要求,在总体设计中采用多发散角分档可调、恒比定时鉴别和厘米级高分辨率计数器等项技术和措施,对激光测距作用距离、回波率以及发散角选择进行详细计算,计算结果表明总体组成能满足指标要求。     

45钢凸轮轴磨损凸轮的激光熔覆再制造

凸轮轴是坦克发动机的关键部件,其服役过程中经常出现由于磨损超差而导致凸轮失效的问题。采用激光熔覆技术实现了坦克凸轮轴的再制造。其中,采用分段调整扫描速度的措施,实现了熔覆层厚度的可控;采用边缘补偿措施,防止了边缘塌陷。提出的凸轮熔覆路径规划,其成形尺寸精度较高。再制造凸轮经磨削加工后满足几何尺寸要求,熔覆涂层组织致密,无裂纹和气孔等缺陷,涂层显微硬度达HV 700～750,满足凸轮轴图纸设计要求。