运行和修复同时进行的固有可用度定时截尾试验方案

针对如何设计一个试验以完成检验系统固有可用度、平均故障间隔时间和平均修复时间等3个指标参数的问题,将试验分为同时进行的可靠性和维修性定时截尾试验2个项目,假设运行时间和修复时间均服从指数分布,且可靠性和维修性试验方案已知,提出了一种固有可用度定时截尾试验方案．该试验方案通过合理选择累积运行时间和累积修复时间,同时满足检验3个指标参数的承制方和使用方风险,可完成对3个指标参数的检验．     

高频电磁注入替代辐照耦合装置的设计研究

为提高电磁注入法的应用频带范围,提出基于定向耦合原理的电磁注入方法,并以某天线及其射频前端构成的互连系统为试验对象,利用单定向耦合器作为注入装置进行了辐照和注入试验,试验证明该注入方法能够准确替代连续波辐照效应试验．进而,理论分析耦合装置的特性并对该装置进行改进,提高其工程实用性．最后,设计耦合装置的指标并计算了对应的散射矩阵,制作完成注入装置的样机．结果表明：耦合装置监测端电压与等效源之间的关系会受到受试设备状态的影响．将两单定向耦合器级联作为注入装置,并以监测端的功率作为等效依据,可保证监测结果在高频时不受线缆上驻波的影响,提高试验的准确性．     

A melt-cast Duan-Zhang-Kim mesoscopic reaction rate model and experiment for shock initiation of melt-cast explosives

A melt-cast Duan-Zhang-Kim (DZK) mesoscopic reaction rate model is developed for the shock initiation of melt-cast explosives based on the pore collapse hot-spot ignition mechanism. A series of shock initiation experiments was performed for the Comp B melt-cast explosive to estimate effects of the loading pressure and the particle size of granular explosive component, and the mesoscopic model is validated against the experimental data. Further numerical simulations indicate that the initial density and formula proportion greatly affect the hot-spot ignition of melt-cast explosives.     

Robust cubature Kalman filter method for the nonlinear alignment of SINS

Nonlinear initial alignment is a significant research topic for strapdown inertial navigation system(SINS).Cubature Kalman filter(CKF)is a popular tool for nonlinear initial alignment.Standard CKF assumes that the statics of the observation noise are pre-given before the filtering process.Therefore,any unpredicted outliers in observation noise will decrease the stability of the filter.In view of this problem,improved CKF method with robustness is proposed.Multiple fading factors are introduced to rescale the obser-vation noise covariance.Then the update stage of the filter can be autonomously tuned,and if there are outliers exist in the observations,the update should be less weighted.Under the Gaussian assumption of KF,the Mahalanobis distance of the innovation vector is supposed to be Chi-square distributed.Therefore a judging index based on Chi-square test is designed to detect the noise outliers,determining whether the fading tune are required.The proposed method is applied in the nonlinear alignment of SINS,and vehicle experiment proves the effective of the proposed method.     

Numerical research on adverse effect of muzzle flow formed by muzzle brake considering secondary combustion

The simulation of the artillery interior and intermediate ballistics problem is performed to investigate the influence of a gas dynamics device, muzzle brake, on the muzzle hazard phenomena, such as flash and blast waves. The correlation of the chemical reactions with the characteristics of the muzzle flow field is analyzed by the simulation for a further understanding of the secondary combustion phenom-enon of the muzzle flow. The novel structure of muzzle flow caused by the muzzle brake is presented by the simultaneous solution of the interior ballistics model and multi-species Navier-Stokes equations in order to analyze the influence of the muzzle brake structure on the chemical reactions. The secondary combustion of the muzzle flow due to the oxygen-supplement chemical reactions is obtained by the chemical reaction kinetic model. The interaction of the blast waves released from the muzzle brake is illustrated in detail and the mechanism of the formation of muzzle flash is analyzed. This research provides a reference for the studies on the suppression of the muzzle flash.     

利用全球探空站背景场资料分析不同掩星数据偏差特性

为验证不同掩星数据反演湿温廓线的精度,需量化分析其误差特性。采用分段线性插值法,以时间窗1 h、水平距离100 km为匹配准则,对0.2~30 km各插值高度层温度的平均偏差和标准差进行统计分析,旨在探究不同掩星数据偏差特性。通过采用2018—2019年期间的全球探空站背景场资料完整数据,评估中国区域不同掩星数据偏差。结果表明:与全球探空站背景场资料相比,各类掩星数据绝对负偏差小于0.4 K,整体均值偏差在-0.5～0.5 K间变化,故二者探测精度相当。通过显著性检验分析发现,折射率相对偏差很小,结合统计量F=0.985 7>0.05可知,不同掩星计划探测精度无显著性差异。