网络雷达对抗系统的相控阵雷达波束扫描分析

针对相控阵雷达波束扫描的捷变特性,提出了基于网络雷达对抗系统的波束扫描分析方法。由于各侦察子系统空间分布特性不同,网络雷达对抗系统所获得的相控阵雷达波束指向判决各不相同。结合DS证据理论,将各个侦察子系统的判决结果融合处理,可有效消除不确定信息,提高波束扫描的判决准确率。通过仿真试验,验证了该方法的有效性和可行性。     

隐身涂料的研究及发展现状

综述了隐身涂料的分类、研究及发展现状,包括可见光隐身涂料,红外隐身涂料,激光隐身涂料、雷迭隐身涂料,声呐隐身涂料和多功能隐身涂料等。     

一种基于UML/OCL的软件测试方法

根据UML/OCL和建模环境提供的软件模型信息,以一个武器装备管理信息系统的装备入库顺序图为例,在分析UML/OCL顺序图的语法和对象间的交互信息的基础上产生测试场景,提供了一种基于UML/OCL的面向对象的软件测试方法,并提出测试自动化的设想,对软件测试有一定的借鉴作用。     

谈火灾证据的搜集利用

提出在火灾调查过程中 ,为查清火灾原因、明确责任 ,应该充分考虑证据的客观性、关联性和合法性 ,及时、全面、细致、合法的搜集证据 ,并对搜集到的证据进行审查、验证 ,确保其真实、完备并能证明案情。为此必须坚持充分运用燃烧原理、规律于证据搜集、利用的每个环节。     

磁浮列车悬浮控制器的电流环分析与优化设计

电流环是磁浮列车悬浮控制器的重要子系统。在分析PI型电流环及最速电流环的控制特点的基础上,设计了一种次速电流环控制器,它具有调节速度快、抗信号扰动能力强、对对象参数不敏感等优点。仿真表明次速电流环的调节速度和最速电流环相当,但在系统中存在干扰信号时,抖动会明显减小。实验表明,次速电流环调试方便,能结合悬浮控制子系统很好地完成悬浮任务。     

X波段矩形波导宽边复合缝隙耦合器的MPSTD算法分析

针对MPSTD算法在波导宽边复合缝隙问题中的应用,重点研究了X波段标准波导宽边复合缝隙耦合器的缝隙谐振长度和散射参量特性。仿真结果表明,将MPSTD算法应用于波导耦合缝隙问题的分析,可实现对该问题的精确建模,具有较高的计算精度和效率。     

An efficient SPH methodology for modelling mechanical characteristics of particulate composites

Particulate composites are one of the widely used materials in producing numerous state-of-the-art components in biomedical, automobile, aerospace including defence technology. Variety of modelling techniques have been adopted in the past to model mechanical behaviour of particulate composites. Due to their favourable properties, particle-based methods provide a convenient platform to model failure or fracture of these composites. Smooth particle hydrodynamics (SPH) is one of such methods which demonstrate excellent potential for modelling failure or fracture of particulate composites in a Lagrangian setting. One of the major challenges in using SPH method for modelling composite materials depends on accurate and efficient way to treat interface and boundary conditions. In this paper, a master-slave method based multi-freedom constraints is proposed to impose essential boundary conditions and interfacial displacement constraints in modelling mechanical behaviour of composite materials using SPH method. The proposed methodology enforces the above constraints more accurately and requires only smaller condition number for system stiffness matrix than the procedures based on typical penalty function approach. A minimum cut-off value-based error criteria is employed to improve the compu-tational efficiency of the proposed methodology. In addition, the proposed method is further enhanced by adopting a modified numerical interpolation scheme along the boundary to increase the accuracy and computational efficiency. The numerical examples demonstrate that the proposed master-slave approach yields better accuracy in enforcing displacement constraints and requires approximately the same computational time as that of penalty method.     

Shock-induced reaction behaviors of functionally graded reactive material

In this paper, the ballistic impact experiments, including impact test chamber and impact double-spaced plates, were conducted to study the reaction behaviors of a novel functionally graded reactive material (FGRM), which was composed of polytetrafluoroethylene/aluminum (PTFE/Al) and PTFE/Al/bismuth trioxide (Bi₂O₃). The experiments showed that the impact direction of the FGRM had a significant effect on the reaction. With the same impact velocity, when the first impact material was PTFE/Al/Bi₂O₃, compared with first impact material PTFE/Al, the FGRM induced higher overpressure in the test chamber and larger damaged area of double-spaced plates. The theoretical model, which considered the shock wave generation and propagation, the effect of the shock wave on reaction efficiency, and penetration behaviors, was developed to analyze the reaction behaviors of the FGRM. The model predicted first impact material of the FGRM with a higher shock impedance was conducive to the reaction of reactive materials. The conclusion of this study provides significant information about the design and application of reactive materials.     

Recent progress on transition metal oxides and carbon-supported transition metal oxides as catalysts for thermal decomposition of ammonium perchlorate

As a main oxidizer in solid composite propellants, ammonium perchlorate (AP) plays an important role because its thermal decomposition behavior has a direct influence on the characteristic of solid com-posite propellants. To improve the performance of solid composite propellant, it is necessary to take measures to modify the thermal decomposition behavior of AP. In recent years, transition metal oxides and carbon-supported transition metal oxides have drawn considerable attention due to their extraor-dinary catalytic activity. In this review, we highlight strategies to enhance the thermal decomposition of AP by tuning morphology, varying the types of metal ion, and coupling with carbon analogue. The enhanced catalytic performance can be ascribed to synergistic effect, increased surface area, more exposed active sites, and accelerated electron transportation and so on. The mechanism of AP decom-position mixed with catalyst has also been briefly summarized. Finally, a conclusive outlook and possible research directions are suggested to address challenges such as lacking practical application in actual formulation of solid composite propellant and batch manufacturing.     

Survivability assessment of spacecraft impacted by orbit debris

To help optimize the spacecraft design and reduce the risk of spacecraft mission failure, a new approach to assess the survivability of spacecraft in orbit is presented here, including the following three steps:1) Sensitivity Analysis of spacecraft. A new sensitivity analysis method, a ray method based on virtual outer wall, is presented here. Using rays to simulate the debris cloud can effectively address the component shadowing issues. 2) Component Vulnerability analysis of spacecraft. A function"Component functional reduction degree — Component physical damage degree"is provided here to clearly describe the component functional reduction. 3) System-level Survivability Assessment of spacecraft. A new method based on expert knowledge reasoning, instead of traditional artificial failure tree method, is presented here to greatly improve the efficiency and accuracy of calculation.