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.     

Adaptive phasefield modelling of crack propagation in orthotropic functionally graded materials

In this work, we extend the recently proposed adaptive phase field method to model fracture in orthotropic functionally graded materials (FGMs). A recovery type error indicator combined with quadtree decomposition is employed for adaptive mesh refinement. The proposed approach is capable of capturing the fracture process with a localized mesh refinement that provides notable gains in computational efficiency. The implementation is validated against experimental data and other nu-merical experiments on orthotropic materials with different material orientations. The results reveal an increase in the stiffness and the maximum force with increasing material orientation angle. The study is then extended to the analysis of orthotropic FGMs. It is observed that, if the gradation in fracture properties is neglected, the material gradient plays a secondary role, with the fracture behaviour being dominated by the orthotropy of the material. However, when the toughness increases along the crack propagation path, a substantial gain in fracture resistance is observed.     

火灾场钢筋混凝土简支梁抗弯性能分析

通过对火灾中钢筋混凝土简支梁截面温度场和材料热力学性能分析,将混凝土分为弹性区和塑性区来分别计算其强度,建立了火灾场简支梁截面内混凝土应力和梁极限抗弯承载力的计算公式,通过具体算例分析了钢筋混凝土简支梁截面温度场和极限承载力的变化规律和原因。     

DN150装配式管线涡街流量检测装置研制

涡街流量检测技术是振动式流量仪表中应用最广泛的一种,具有测量范围宽、精度较高、重复性好、可靠性高、不受介质物性和组分变化影响、不需精细过滤、流阻小等一系列优点,特别适合在装配式输油管线上应用.介绍了DN150装配式管线涡街流量检测装置,重点介绍研制中解决的几个关键技术问题.     

防空导弹武器系统网络化作战统一指令场技术研究

分析了未来防空导弹武器系统网络化作战对统一指令场的要求,提出将直接扩频码分多址技术用于统一指令场,并在典型的进攻模式和战场环境下针对要地保护区域给出了一种合理的武器系统配置以及统一指令场设计。     

磁镜场约束等离子体的粒子模拟

用PIC粒子模拟的方法描绘具有初始速度分布的等离子体在磁镜场中的运动状态 ,得出等离子体在磁镜场中的运动轨迹图 ,形象表现了磁镜场对等离子体的约束作用 ,表明用PIC粒子模拟方法探索在磁镜场中等离子体运动的物理过程和规律是可行的和有效的 .     

三维高超音速干扰流场数值模拟与实验验证

采用Osher Chakraverthy的TVD格式、Baldwin Lomax湍流模型和LU SSOR隐式方法求解了完全NS方程 ,数值模拟了三维高超音速绕流与横向喷流干扰流场。并在高超音速炮风洞中开展了喷流实验研究 ,对该喷流流场的数值计算结果进行实验验证     

电力设备局部放电在线监测用传感器传输特性分析

电流传感器是电力设备局部放电在线监测系统中的一个重要组成部分 ,其局部放电信号传输特性直接影响测量结果。本文对电流传感器传输特性进行了理论分析 ,有关分析结果与实测结果一致     

磁悬挂天平校准关系的非线性拟合

以磁悬挂天平系统的校准为研究背景 ,介绍了传统的校准关系的线性建模方案 ,针对其存在的缺陷 ,并结合校准实验数据的特点 ,提出了非线性拟合的改进方案 ,该方案借鉴了主成份分析法的合理成分 ,采用三次样条拟合方法建立校准关系 ,获得了令人满意的实际效果 ,最后 ,还定量比较了校准拟合的改进方案和传统的线性建模方案。     

电子分析天平温漂与时漂的自动补偿

温漂和时漂是电子分析天平产生误差的主要原因 ,其自动补偿具有重要意义。本文介绍了电子分析天平的工作原理 ,分析了电子分析天平温漂、时漂的产生机理 ,提出了一系列克服漂移的自动补偿方法 ,给出了传感器、硬件电路和软件等几方面的自动补偿方案 ,实际应用表明这些补偿方法是切实可行的。