凝视型红外搜索跟踪系统探测能力的分析

探测能力的强弱是广大凝视型红外搜索跟踪系统设计者和使用者一直关心的问题。对作用距离数学模型中影响探测能力的主要因素如目标、光学系统口径等进行了分析,还讨论了模型中未曾提到的一些因素,如路径辐射、光谱匹配等对探测能力影响的方式、程度。分析结果为增强凝视型红外搜索跟踪系统的探测能力提供了理论依据。     

CCD探测器搜索跟踪系统的作用距离分析

以辐射度量为标准,从目标信号、背景信号差值与探测器噪声比值的角度出发,变换凝视型红外搜索跟踪系统的作用距离模型,建立了CCD搜索跟踪系统点目标的作用距离方程。解决了目标为发光体、反射体,以及CCD为不同灵敏度表述方式的跟踪系统的作用距离计算,实例验证计算值与实测值相吻合,为CCD跟踪系统的设计和性能评估提供了理论依据。     

长波红外对常温目标的跟踪成像研究

靶场观测中存在大量不发光和表面温度接近常温的低温目标,根据它们的光谱辐射特性、背景辐射特性和大气透过率与目标距离的关系,分别选择了中波和长波红外探测器对降落伞进行气球放飞试验。试验结果表明,长波红外探测器对常温目标的探测要优于中波红外。选择分辨力320×256 的碲镉汞探测器作探测能力实验,以 SNR≥5 为可探测条件,当目标表面温度大于 260K时,对直径 5m 的降落伞的作用距离可达 50Km。     

红外焦平面阵列相对光谱响应测试系统

由电子41所研制的红外焦平面阵列相对光谱响应测试系统采用单光路标准替代法进行测量，系统组成灵活并可扩展，配合自行研制的图形发生器，偏置，时钟驱动、数据采集子系统，可以满足不同被测器件的需要。     

提高电视跟踪系统作用距离的方法探讨

本文从影响电视跟踪系统作用距离的因素:目标大小、对比度、背景以及信噪比出发,总结了作者多年来在提高电视跟踪系统作用距离方面所做的工作。除此之外,作者还提出了一些新颖的提高电视跟踪系统作用距离的方法。     

红外警戒系统点目标检测距离理论分析

给出了红外警戒系统点目标探测距离的计算模型与公式,分析了影响点目标探测距离的参数间关系,并得出有关目标提取算法及传感器参数选择的几点重要结论。     

应用于弹丸跟踪测量的红外器件工作波段选择

目的：探讨利用红外焦平面热像仪对常规快速弹丸目标进行跟踪与测量，以提高对弹丸目标的跟踪测量能力。方法：对靶场试验中常用弹丸目标的光谱辐射特性，背景辐射特性以及大气透过率进行了综合理论分析，并在理论分析的基础上结合试验结果进行分析，结果：对工作波段3um-5um,8um-12um的红外焦平面热像仪以及可见光电视的探测能力进行了比较。结论：响应工作波段为3um-5um的红外热像仪最适于作常规弹丸目标的跟踪测量设备。     

提高小型跟踪测量电视系统探测距离的方法

介绍一种实际使用的小型跟踪测量电视系统 ,它通过提高光学系统透过率和增强图象对比度 ,以及采用数字背景拟合自适应电平检测的方法 ,达到远距离探测目标的任务。     

非致冷热电型红外焦平面阵列用探测材料的研究进展

归纳了非致冷红外焦平面阵列（ＵＦＰＡ）技术自提出、发展直至趋于成熟以来,国内外曾研究报道过的近百种热电型探测材料,对其中前景看好的Ｓｉ、Ｔｉ、ＶＯｘ等微测辐射热计材料和（Ｂａ、Ｓｒ）ＴｉＯ２等热释电材料进行了重点评述。     

一种极值搜索的齿轮系统振动信号阶次跟踪方法

在变速工况下,齿轮系统的振动信号具有非平稳性,频谱特征模糊,不利于特征提取和故障诊断。阶次跟踪方法作为一种非平稳信号分析方法,将原信号从时间域转换到角度域,有助于抑制变转速导致的频率模糊现象。广泛应用的计算阶次跟踪分析方法在实现等角度重采样过程中,通过提取瞬时转速积分求取瞬时角位移,或者基于相位解调获取角度-时间关系,受限于积分累计误差或小的转速跟踪范围。利用齿轮系统啮合振动信号峰峰值对应的等角度间隔特征,提出一种基于时域信号极值搜索的无键相阶次跟踪方法。所提方法不需要通过转速积分获取瞬时角位移,同时允许较大转速变化范围,降低了阶次分析域变换过程的误差,抗噪性能良好,使阶次谱能量集中度和特征成分辨识度得到明显提高。理论分析、仿真对比分析和试验测试结果均验证了所提方法的有效性,适用于变转速工况下的齿轮箱非平稳振动信号频谱分析和故障诊断。     

列车-轨道系统竖向动力分析的车辆轨道单元模型

根据列车-轨道系统运动的特点,提出了适合该问题动力学分析的新型车辆单元和轨道单元,运用有限元方法和Lagrange方程,推导了两种单元的刚度矩阵、质量矩阵和阻尼矩阵。整个列车-轨道系统只需离散成车辆单元和轨道单元,其中轨道系统离散成轨道单元,一节车辆离散成一个车辆单元。该模型具有程序编制容易、计算效率高的特点。作为应用实例,给出单轮通过和考虑轨道完全平顺和具有随机不平顺条件下整车通过时车辆和轨道动力响应分析的二个算例。     

A reverse engineering algorithm for mining a causal system model from system data

Although having structural system models which determine system behaviours is critical to plan, control and manage many complex systems (e.g. manufacturing and production systems), we often do not have pre-defined structural system models. We need to perform reverse engineering which is to collect and mine observable system data in order to discover structural system models. This paper presents a reverse engineering algorithm that can be used to discover a causal system model which is one kind of structural system model and represents causal relations of system factors. In a causal relation, the presence of one system factor causes the presence of another system factor. The paper also shows the computational complexity of the algorithm. The paper presents the application and performance of the reverse engineering algorithms to data in two application fields.     

提高脉冲LD测距系统测距能力的一种方法

从激光测距机的噪声构成分析入手,寻求提高脉冲 LD 测距机测距能力的方法。脉冲 LD测距系统的噪声主要包括热噪声、散粒噪声、背景噪声、暗电流噪声及放大器噪声。在一定的光功率、暗电流情况下,LD 测距的测距能力更容易受背景噪声的影响。研究表明,LD 测距系统中探测器偏压的变化只补偿温度变化,由此提出,在背景光照射较强时让背景噪声参与偏压调整从而抑制背景噪声的方案。实验结果证实,强背景下的信噪比提高 1 倍以上,测距能力提高 1 倍。     

Evaluation of the unavailability of a multistate-component system using a binary model

In this article, we discuss the problem of computing the unavailability of a multistate-component system. We propose the use of a Boolean model describing as much as possible about the system structure. A theorem of two-sided estimation of the approximation error enables us to check the calculation accuracy. An application of this method to a nuclear safety system is offered.     

Development of a mathematical model for the effect of temperature and relative humidity on the water vapour permeability of plastic films

The water vapour permeability constants of three flexible films (LDPE, PET and a laminate of both films) were determined at 20, 30 and 40 °C and from 55 to 90% relative humidities. The relationship between permeability and temperature followed the Arrhenius model for the three films. The relative humidity also influenced the permeability of the films. A mathematical model describing permeance (P/X - the permeability of laminates or films) as a function of external relative humidity and temperature was developed. The model can be used to predict the permeance of the three films at different temperatures and relative humidities.     

Experimental verification of a mathematical model for simulation of industrial refrigeration plants

A mathematical model, proposed for simulation of food refrigeration processes, was tested against experimental data collected in a New Zealand meat processing plant which had a total refrigeration capacity of 2.5 MW. Predicted air temperatures in freezing and chilling operations followed the same trends as measured data. Differences were shown to be more attributable to uncertainties in data than to deficiencies in the formulation of the mathematical model. The model is considered suitable for use in simulation of a wide range of food refrigeration processes. Such simulations provide useful information about plant performance that cannot be obtained by steady state analysis. Predictions were worst for short times immediately following step changes in plant operation; should more accurate simulation of these periods be required a different form of mathematical model is needed.     

A mathematical model of a system for regulating a vacuum radiator of variable temperature

The stability of a multiloop system for controlling a highly accurate radiator is analyzed. __________ Translated from Izmeritel’naya Tekhnika No. 9, pp. 42–44, September, 2007.     

A mathematical model and its analytical solution for slow depressurization of a gas-filled vessel

The operation safety of depressurizing a high-pressure gas-filled vessel is of crucial importance in petroleum, chemical and biological processing industries. The present study describes a simple model of a slow depressurization process and derives its analytical solution in a recurrence form. This analytical solution is expected to be useful for engineering applications and for the assessment of either detailed numerical simulations or experimental data.