基于一维距离像的导弹目标运动特征提取方法

根据导弹目标运动方式及其回波特点,提出了一种基于一维距离像的运动目标特征提取方法。在对回波进行全去斜率处理后获得目标一维像。通过观测一维像序列的长度变化周期,提取目标的章动频率;根据距离像在成像窗口中的位置,获取雷达和目标的径向距离;利用相邻距离像相关方法,获取距离像平移位置,从而推出雷达—目标的径向速度。进行了相应的仿真实验,结果表明了该方法的有效性。     

离散系统的绝对稳定性

给出了离散系统绝对稳定性问题的充分条件:约束条件下的矩阵不等式的正定解;基于这一思路可以构造控制器来镇定一类非线性系统;最后还给出了设计实例以说明结果的有效性。     

二维超声速空气引射器启动特性试验研究

（静）超声速引射器是高空模拟试车台的重要组件,在发动机启动前利用引射器对试验舱预抽真空可避免发动机启动初始时刻燃气漏入试验舱造成燃气在发动机中分离,对获取发动机在高空环境下的完整推力特性具有重要意义。而该工况下超声速引射器的启动过程是引射器工作过程中最为恶劣的工况,设计不合理的引射器会导致启动压力过高甚至不能实现启动。建立了缩比超声速空气引射器试验台对超声速引射器的启动特性进行研究,采用压力测量方法结合纹影技术对超声速引射器处于极限启动压比时的流场进行了描述,研究结果表明混合室收缩比越小,引射器极限启动压比越低。同时给出了定位超声速引射器不启动原因的判据：当引射器不启动是由引射总压不足引起时,盲腔压力在引射总压提高时降低,并在临界启动状态下达到最小值;而由混合室收缩比过小导致的引射器不启动在引射总压提高时盲腔压力单调上升。     

星载InSAR均匀相位构形的空间基线稳定性

星载InSAR(干涉式合成孔径雷达)在对地观测任务中具有广泛的应用,其空间基线随卫星编队平台的运动而变化。本文基于卫星编队的构形原理,定义了星载InSAR均匀相位构形。根据干涉测量原理定义了相关基线及其稳定度,研究了不同均匀相位构形下星载InSAR的基线稳定性。     

Preparation and characterization of HMX/EVA/hBNNSs micro-composites with improved thermal stability and reduced sensitivity

Hexagonal boron nitride nanosheets(HBNNSs)have huge potential in the field of coating materials owing to their remarkable chemical stability,mechanical strength and thermal conductivity.Thin-layer hBNNSs were obtained by a liquid-phase exfoliation of h-BN powders and incorporated into EVA coatings for improving the safety performance of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX).HBNNSs and ethylene-vinyl acetate copolymer(EVA)were introduced to HMX by a solvent-slurry process.For com-parison,the HMX/EVA and HMX/EVA/graphene(HMX/EVA/G)composites were also prepared by a similar process.The morphology,crystal form,surface element distribution,thermal decomposition property and impact sensitivity of HMX/EVA/hBNNSs composites were contrastively investigated.Results showed that as prepared HMX/EVA/hBNNSs composites were well coated with hBNNSs and EVA,and exhibited better thermal stability and lower impact sensitivity than that of HMX/EVA and HMX/EVA/G composites,suggesting superior performance of desensitization of hBNNSs in explosives.     

Electronic warfare in the optical band: Main features,examples and selected measurement data

The paper presents the possibilities of, and methods for, acquiring, analysing and processing optical signals in order to recognise, identify and counteract threats on the contemporary battleground. The main ways electronic warfare is waged in the optical band of the electromagnetic wave spectrum have been formulated, including the acquisition of optical emitter signatures, as well as ultraviolet (UV) and thermal (IR) signatures. The physical parameters and values describing the emission of laser radiation are discussed, including their importance in terms of creating optical signatures. Moreover, it has been shown that in the transformation of optical signals into signatures, only their spectral and temporal parameters can be applied. This was confirmed in experimental part of the paper, which includes our own measurements of spectral and temporal emission characteristics for three types of binocular laser rangefinders. It has been further shown that through simple registration and quick analysis involving comparison of emission time parameters in the case of UV signatures in “solar-blind” band, various events can be identified quickly and faultlessly. The same is true for IR signatures, where the amplitudes of the recorded signal for several wavelengths are compared. This was confirmed experimentally for UV signatures by registering and then analyzing signals from several events during military exercises at a training ground, namely Rocket Propelled Grenade (RPG) launches and explosions after hitting targets, trinitrotoluene (TNT) explosions, firing armour-piercing, fin-stabilised, discarding sabots (APFSDS) or high explosive (HE) projectiles. The final section describes a proposed model database of emitters, created as a result of analysing and transforming the recorded signals into optical signatures.     

Insensitive energetic microspheres DAAF/RDX fabricated by facile molecular self-assembly

Insensitive energetic materials are promising in the defense weapons field. However, energetic materials still suffer from great challenges and the concern about their safety limits their utilization. In this work, insensitive energetic explosive 3,3′-diamino-4,4′-azoxyfurazan/hexahydro-1,3,5-trinitro-1,3,5-triazine (DAAF/RDX) microspheres were fabricated by self-assembly method. Rod-like DAAF/RDX was prepared by mechanical ball milling for comparison. DAAF/RDX composites with different mass ratios (90:10, 80:20, and 70:30) were obtained. The morphologies and structures of as-obtained DAAF/RDX composites were characterized by scanning electron microscopy (SEM), powder x-ray diffraction (PXRD) and fourier transform infrared spectroscopy (FT-IR). The results showed that DAAF/RDX microspheres exhibited regular shaped microspheres with sizes from 0.5 to 1.2 μm. There was no crystal transition during the modification process. The thermal properties of as-obtained materials were then evaluated by differential scanning calorimetry (DSC) and materials studio software. DAAF/RDX microspheres showed an advanced decomposition peak temperature compared with rod-like DAAF/RDX. The binding energy and peak temperature values at zero β_i (T_P0) of DAAF/RDX (90:10) increased by 36.77 kJ/mol, 1.6 °C, and 58.11 kJ/mol, 12.3 °C compared to DAAF/RDX (80:20) and DAAF/RDX (70:30), indicating the better thermal stability of DAAF/RDX (90:10). The characteristic drop height (H₅₀) of DAAF/RDX (higher than 100 cm) composites was higher than that of raw RDX (25 cm), suggesting significant improvements in mechanical safety. The preparation of DAAF/RDX microspheres is promising for the desensitization of RDX and useful for the formation of other materials and future wide applications.     

Van der Pol-Duffing系统的非共振Hopf分叉

用多尺度法求出了系统的一次近似平均方程和极坐标形成的分叉响应方程。研究了系统非共振情况下的平衡点性质和Hopf分叉,讨论了零解和极限环的稳定性     

新型F1ash单片机智能温控系统设计

采用新型的Flash单片机、信号采集电路与温控电路等构成一个对固体火箭发动机温控系统 ,满足其固体火药的初始温度设计要求。     

热边界层流动中管道的热损失

在高粘液体管道输送中,利用热边界层减阻需确定热流量的计算。热边界层流动中管道的各种热损失是总热流量的一部分。热损失有管内、管外及保温层三种形式。管外热损失是向周围的空气散发的,通过对流的形式发生。管内的热损失是导热或对流。保温层的热损失主要是导热。利用热边界层理论的成果,给出了各种传热系数和管道热损失的计算公式,并给出了多个计算实例。