地面附近的高空核爆电磁脉冲环境

 主要研究在高空核爆的双指数类型电磁脉冲平面波入射时，地面附近的电磁脉冲环境。计算给出了在不同入射波状态，不同地表介质电气特性和距地面不同高度等条件下的电磁脉冲环境参数，归纳了一些规律性认识。结果显示：地面附近的电场会随距地面高度的不同而发生显著的变化，对于水平场分量，其反射场总是试图抵消入射场，而对于垂直场分量，其反射场叠加在入射场上，使得地面附近的垂直场强幅值一般大于入射波场强幅值；当入射波仰角增大时，合成电场波形的脉冲宽度会变宽；地表介质的电气特性参数不同也会对地面附近电场的波形和幅值造成一定的影响。     

中国聚变工程实验堆真空室超压保护系统中爆破片的选型与计算

参照相关标准,对聚变装置真空室超压保护系统(VVPSS)中爆破片进行了选型。结合VVPSS的工作要求,完成了爆破片的设计计算,初步得到爆破片直径为882mm,厚度为1mm。利用有限元分析软件对多种型号爆破片进行结构分析比较,最终选用了反拱环向开缝型爆破片。对最终选定的爆破片进行优化设计,使其达到设计要求。     

Doubly stochastic Yule cascades (Part I): The explosion problem in the time-reversible case

Motivated by the probabilistic methods for nonlinear differential equations introduced by McKean (1975) for the Kolmogorov-Petrovski-Piskunov (KPP) equation, and by Le Jan and Sznitman (1997) for the incompressible Navier-Stokes equations (NSE), we identify a new class of stochastic cascade models, referred to as doubly stochastic Yule cascades. We establish non-explosion criteria under the assumption that the randomization of Yule intensities from generation to generation is by an ergodic time-reversible Markov process. In addition to the cascade models that arise in the analysis of certain deterministic nonlinear differential equations, this model includes the multiplicative branching random walks, the branching Markov processes, and the stochastic generalizations of the percolation and/or cell ageing models introduced by Aldous and Shields (1988) and independently by Athreya (1985).     

Theoretical studies on the structure,sensitivity, density,thermodynamic properties and detonation performance of dinitrobitriazoles

Azodinitro- and dinitroethylene-bridged bitriazoles are of interest in the contest of high explosives, and were found to have true local energy minima at the B3LYP/aug-cc-pVDZ level of theory. The optimised structures, vibrational frequencies and thermodynamic quantities for bitriazoles were obtained in the ground state. Kamlet–Jacobs equations were used to evaluate the performance of bitriazoles based on the predicted density and the calculated heat of explosion. Detonation properties (D = 8.12 to 9.23 km s^?1 and P = 28.0 to 39.83 GPa) of bitriazoles were found to be promising compared with those of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, D = 8.75 km s^?1 and P = 34.7 GPa) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX, D = 8.96 km s^?1 and P = 35.96 GPa). The fusion of azoles particularly appears to be a promising area for investigation, since it may lead to the desirable consequences of higher heat of explosion, higher density and thus improved detonation performance.     

基于双天线的高精度GPS定位测向系统及其在无人水面艇上的应用

介绍了一种基于双天线的高精度GPS定位测向系统,该系统可以实现精确定位、测向。分别从硬件和软件两个方面详细介绍了双天线GPS定位测向系统,双天线GPS系统的硬件部分主要由GPS接收机、主天线和从天线组成,GPS接收机内置OEM板和底层通信板,软件部分主要解析GPS数据处理模块的软件工作流程。通过静态实验和动态实验分析系统定位、测向的精度,实验数据表明静态实验的经度的标准偏差为0.3155米,纬度的标准偏差为0.1962米,第一次静态实验的测向标准偏差为0.0981°,第二次静态实验的测向标准偏差为0.0926°。最后,将此系统应用到无人水面艇,进行直线路径跟踪水上试验。     

Effects of multiple blade interaction on the containment of blade fragments during a rotor failure

A finite element analysis is used to study the impact and the containment aspects of rotor blade fragments that are produced during a aircraft jet engine rotor failure. The impact and containment studies are performed on a ring-type containment structure and various fragment types are considered in this study. For each type of fragment, the ring thickness is varied incrementally and the ring response, residual kinetic energy level of the fragments, magnitude of impact forces and the overall containment or failure are determined. First, only a single fragment is considered and the rotor is assumed to contain no other blades. Next, the remaining blades are introduced and the effects of multiple collisions with the other blades on the containment are analyzed. The explicit, nonlinear finite element code Dyna3d is used for the numerical computations in this study and the results are compared with the experimental results performed on a T58 rotor at the spin facility of the Naval Air Propulsion Test Center.     

射流冲击模型在水下爆炸实验中的应用研究

 为研究射流冲击载荷对结构的作用效果,从理论和数值角度研究了射流的载荷特性,以舱段模型实验为研究对象,建立了射流计算模型,结合实验数据,对射流冲击问题进行了分析。结果表明,射流冲击能够造成结构强烈的局部响应,某些情况下,射流冲击载荷引起的结构响应甚至比冲击波载荷引起的响应更大。因此,中近场水下爆炸实验需要考虑射流的影响。建立的射流模型能够较好地反映射流冲击的载荷特性,为水下爆炸实验分析提供了一种新的手段。     

不同水底介质对有限域中装药沉底爆炸特性的影响

通过开展装药沉底爆炸原理性实验研究,得到了不同水底条件对装药沉底爆炸气泡运动和冲击波压力的影响规律:沉底装药水下爆炸气泡通常呈半球形,依附在水底并同时急剧膨胀达到最大半径,随后气泡做收缩运动并连带水底介质颗粒迅速上浮,同时形状发生显著变化,如在石底和泥底时气泡在水底射流的作用下呈蘑菇状上浮,砂底时气泡则呈现出柱状上浮、未出现明显脉动运动即已坍塌破裂;沉底爆炸与水底介质发生强烈耦合作用而形成不同程度的反射波,通常水下石底的反射冲击波较泥底和砂底更强烈,且一般迭加后的冲击波峰值压力高于入射波阵面压力;不同水底介质条件下,装药与水底发生的强烈耦合作用均对水底造成强冲击破坏。     

基于量纲分析和达西定律的地下化学爆炸气体泄漏规律

针对周围是均匀岩石介质的地下化学爆炸,研究爆炸后爆室内气体的泄漏规律.利用量纲分析,得到影响气体泄漏时间的主要物理量,包括气体动力学粘度、爆室内超压、围岩孔隙率及围岩厚度的平方与渗透率的比值等,并初步给出它们之间的函数关系.然后基于达西定律,推导计算气体泄漏时间的解析公式.得到的气体泄漏时间计算公式与通过量纲分析得到的定性函数关系式完全相符,二者从不同的角度对同一问题给出了相容的结果.可为地下化学爆炸气体泄漏的理论分析和规律性研究提供研究思路和工具,为地下爆炸有关的工程估算提供参考依据.     

基于消息传递接口的空中爆炸问题的并行计算

研究了用于处理三维多物质欧拉网格的模糊界面技术以及算法存在的数据相关性问题,提出了解决数据相关性的方法。采用基于消息传递接口(MPI)模式,设计出了相应的MMIC-3D并行程序,得到了无限空气介质中爆炸的三维数值模拟结果,计算结果与实际的实验现象及规律基本吻合。在共享存储的全对称多处理机(SMP)上进行了测试,得到了理想的加速比。