卫星地面站环境电磁辐射的预测

本文从环境保护和电磁兼容的研究目的出发,论述了卫星地面站电磁辐射公众暴露水平的测量原理、测量方法以及理论计算。根据测量和理论计算结果,预测卫星地面站电磁辐射对环境的影响,并作出卫生学评价。     

基于光纤珐珀结构的耐高温应变传感器研究

为了研制一种适用于反应堆一回路高温环境下机械测量的微型应变传感器,基于光纤珐珀（FP）结构光学原理、解调原理和封装技术研究,提出传感器的热机耦合模型,设计出一种基于光纤FP结构的耐高温应变传感器及其解调系统,并对其在常温空气中和高温中压水环境中进行动态测试。研究和测试结果表明,该高温光纤FP应变传感器及其解调系统能够在高温、中压以及水环境下稳定工作,且应变传感器的测量工作范围为0～4000με,解调系统速度达到5 kHz。本研究设计的高温光纤FP应变传感器及其解调系统能够用于反应堆一回路高温环境下的应变测量,从而为反应堆一回路高温环境下的监测提供了一种有效的监测方法。     

卫星遥感及其应用的发展态势

简述了卫星遥感传感器分辨率、辐射精度、卫星运行模式、载荷形式、数据处理,以及遥感应用等方面的最新进展,卫星遥感传感器分辨率显著提高,多传感器的有效集成是21世纪卫星遥感的新概念和新技术。后遥感应用技术是遥感技术深化应用的重要组成部分,具有重要的实践意义。     

高湿度对表面α活度测量影响的研究

通过分析相对湿度对空气层密度和表面吸附的影响,阐明在高湿度环境下表面α活度测量产生误差的原因.并使用似φ45mmα面源,在20℃下5个不同相对湿度条件时测定了MicrocontⅡ表面αβ测量仪的表面活度响应因子,初步阐明的相对湿度对表面α活度测量的影响规律,可为高湿度条件下表面α活度测量工作提供一定的借鉴.     

堆芯测量传感器发展现状及其在燃料元件考验中的应用

简单介绍了发展堆芯测量传感器的重要意义,我国近年来各种堆芯测量传感器的研制和发展现状以及某些堆芯传感器在秦山核电站燃料元件考验中的初步应用。这些传感器主要包括测量燃料中心温度的套管式高温W/Re热电偶组件,测量燃料包壳伸长的差动变压器型位移传感器,测量裂变气体内压的膜片式压力传感器,测量燃料棒相对功率分布的γ温度计,测量辐照燃料元件中子通量和通量分布的自给能探测器和测量燃料包壳温度和考验元件出入口冷却剂温度的铠装热电偶等等。     

基于β粒子源的空腔式粉尘传感器研究

为实现管道烟尘浓度的连续实时测量,设计了一种基于β粒子源的无动力粉尘传感器。传感器基于平板型空腔结构,采用流体力学模拟软件ANSYS fluent 15.0对传感器内部流场进行研究,以优化设计传感器进气口特征、源面积、源 收集极间距等结构参数,并在静态无风和风洞环境下对传感器相关参数进行验证。在风洞内,温度为30～33℃,含湿量为1%～2%,风速为（9.7±0.2） m/s条件下,研究传感器响应与粉尘浓度之间的关系。结果显示,从34 ℃变化至233 ℃时,传感器响应变化约50%;含湿量从6.52%增加到10.65%时,传感器响应变化约30%;在风洞内较低湿度和较低温度条件下,滤膜采样浓度为13.5、26.8、33.6、47.5、63.3 mg•m^-3时,传感器示值对应为16.6、30.4、38.1、45.3、53.2 mg•m^-3。研究证实了基于β粒子源的传感器用于粉尘测量的可行性,实验获得了环境温湿度条件变化与β粒子源的无动力粉尘传感器响应值的初步关系,但对于温湿度变化引起粉尘浓度测量偏差需进一步研究。     

堆芯测量传感器发展现状及其在燃料元件考验中的应用

简单介绍了发展堆芯测量传感器的重要意义,我国近年来各种堆芯测量传感器的研制和发展现状以及某些堆芯传感器在秦山核电站燃料元件考验中的初步应用。这些传感器主要包括测量燃料中心温度的套管式高温W/Re热电偶组件,测量燃料包壳伸长的差动变压器型位移传感器,测量裂变气体内压的膜片式压力传感器,测量燃料棒相对功率分布的γ温度计,测量辐照然料元件中子通量和通量分布的自给能探测器和测量燃料包壳温度和考验元件出入口冷却剂温度的铠装热电偶等等。     

基于β粒子源的空腔式粉尘传感器研究

为实现管道烟尘浓度的连续实时测量,设计了一种基于β粒子源的无动力粉尘传感器。传感器基于平板型空腔结构,采用流体力学模拟软件ANSYS fluent 15.0对传感器内部流场进行研究,以优化设计传感器进气口特征、源面积、源-收集极间距等结构参数,并在静态无风和风洞环境下对传感器相关参数进行验证。在风洞内,温度为30～33℃,含湿量为1%～2%,风速为(9.7±0.2) m/s条件下,研究传感器响应与粉尘浓度之间的关系。结果显示,从34℃变化至233℃时,传感器响应变化约50%;含湿量从6.52%增加到10.65%时,传感器响应变化约30%;在风洞内较低湿度和较低温度条件下,滤膜采样浓度为13.5、26.8、33.6、47.5、63.3 mg·m~(-3)时,传感器示值对应为16.6、30.4、38.1、45.3、53.2 mg·m~(-3)。研究证实了基于β粒子源的传感器用于粉尘测量的可行性,实验获得了环境温湿度条件变化与β粒子源的无动力粉尘传感器响应值的初步关系,但对于温湿度变化引起粉尘浓度测量偏差需进一步研究。     

基于轮转电极的多电极电容式棒位测量传感器静态特性研究

电容式棒位测量传感器是200 MW低温核供热堆控制棒水压驱动系统的关键测量部件,其精度和可靠性直接关系到反应堆的安全性。本文基于有限元方法建立了电容式棒位测量传感器的理论模型,对两电极电容式棒位测量传感器检测场的灵敏度分布特性进行了分析。结果表明,在检测场内存在一个特定区域,被测杆向该区域偏移时偏心误差较小。基于该特性提出了多电极电容式棒位测量传感器的设计方案和轮转电极的电容检测方法,针对该传感器,利用有限元模型进行了传感器结构优化和被测杆偏心误差分析,完成了传感器静态特性实验并验证了模型计算结果。分析结果表明,多电极电容式棒位测量传感器与轮转电极的电容检测方法能有效利用检测场的灵敏度分布特性,优化后传感器的偏心误差能达到棒位测量不失步的要求。研究成果为电容式棒位测量传感器的设计和优化提供了新的方向。     

90Sr-90Y源半导体器件辐照效应在线测量系统

介绍了一种新型半导体效应参数测量装置,以＾９０Ｓｒ－＾９０Ｙ为模型源辐射装置与半导体参数测量仪共同组成半导体器件辐射效应测量系统,可进行各类器件和电路总剂量辐照效应测量与分析,系统实现了在线测量和辐射剂量率的连续调节,特别适宜对于卫星空间辐射环境的模拟。     

卫星部件内部充放电试验与仿真

内部充放电效应是主要空间环境效应之一,对中高轨卫星的威胁很大。当前的内部充放电研究主要关注材料,试验手段和计算机仿真工具不能处理三维卫星结构,无法满足工程应用需要,将关注对象拓展至具有复杂结构的卫星部件是有意义的。本工作尝试利用90Sr-90Y源,对太阳帆板驱动机构导电环样品进行了模拟试验,测得不同条件下样品表面电位的差异,并观测到放电现象。同时,利用蒙特卡罗模拟和有限元分析,得到了样品内部充电电场和电位的空间分布。证明利用现有条件进行部件级的模拟试验和仿真分析是可行的。具体的试验和仿真结果,对指导太阳帆板驱动机构内部充放电防护设计,也具有一定意义。     

非规则边界条件对介质内带电的影响研究

采用三维仿真研究复杂介质结构深层充电问题,有利于发现由非规则边界条件造成的局部场强畸变点。本文给出了深层充电的三维仿真方案,并进行了实验验证。对正面局部接地情况下的电路板内带电进行了三维仿真,考察了局部接地边缘出现的场强畸变特征,并定量分析了金属走线边角曲率半径对畸变场强的作用规律。在地球同步轨道恶劣电子辐射环境下,2 mm厚屏蔽铝板下3 mm厚电路板的充电结果表明：电路板正面接地与非接地边线处存在显著的场强畸变增大现象,场强峰值较一维规则接地情况高出2个数量级,达到10.7 V/m量级。增大金属走线边角曲率半径可缓解局部泄漏电流密度的汇集效应,从而降低场强峰值。相关结论可为有效规避电路板内带电风险提供有益参考。     

地球同步轨道航天器深层充放电试验的一种方案

介绍了地球同步轨道航天器深层充放电试验的目的与意义,并提出一种在航天器上搭载深层充放电(ESD)在轨的试验装置的方案。对航天器深层充放电的事件、频度及其强度和在导线内的耦合程度进行测量。     

星用介质材料深层充电效应仿真分析

高能带电粒子与航天器介质材料相互作用引起的深层带电现象,一直是威胁航天器安全运行的重要因素之一。随着航天器在轨飞行时间的增长,以及航天器飞行在中高轨道,其遭遇空间高能电子引起的介质深层充放电效应越来越严重。针对星用介质材料的深层充放电效应问题,提出了一种平板型多层结构的介质深层充放电分析模型,利用FLUKA仿真和带电分析程序分析了多层介质材料内部电荷沉积情况,研究了介质中叠合的金属层厚度和层数两个不同因素对充电电荷沉积的影响。仿真结果表明,建立的物理模型能有效地得到介质深层的电荷沉积分布特性,其研究结果可直接应用于空间辐射效应监测载荷中。     

Surface Charging Controlling of the Chinese Space Station with Hollow Cathode Plasma Contactor

A highly charged manned spacecraft threatens the life of an astronaut and extravehicular activity, which can be effectively reduced by controlling the spacecraft surface charging.In this article, the controlling of surface charging on Chinese Space Station(CSS) is investigated,and a method to reduce the negative potential to the CSS is the emission electron with a hollow cathode plasma contactor. The analysis is obtained that the high voltage(HV) solar array of the CSS collecting electron current can reach 4.5 A, which can be eliminated by emitting an adequate electron current on the CSS. The theoretical analysis and experimental results are addressed,when the minimum xenon flow rate of the hollow cathode is 4.0 sccm, the emission electron current can neutralize the collected electron current, which ensures that the potential of the CSS can be controlled in a range of less than 21 V, satisfied with safety voltage. The results can provide a significant reference value to define a flow rate to the potential controlling programme for CSS.     

The effect of positive/negative ion on the dust grain charging process in a Vasyliunas-Cairns (VC)-distributed dusty plasma system

Charging mechanism of dust particles has been considered as a growing research area in dusty plasma physics because of its exciting results. In this paper, we consider a low-temperature non- equilibrium multispecies plasma model, which consists of Vasyliunas–Cairns (VC) distributed electrons, negative/positive streaming ions, and negatively-charged dust grains to explain the charging mechanism of dust grains. The main theme of this work is to derive expressions of currents for negatively-charged dust grains (considering an equilibrium state position) in the plasma environment comprised of electrons and positive/negative streaming ions using the VC distribution function. Our proposed model shows that the dust grain surface potential is significantly affected by different plasma parameters such as the negative ion streaming velocity (S_n), positive ion streaming velocity (S_i), spectral indices of VC distribution, negative ion charging state (Z_n), positive ion charging state (Z_i), and negative ion number density (ρ).     

Surface Potential of Dust Grains at the Sheath Edge of Electronegative Dusty Plasmas

In this paper we investigate the dust surface potential at the sheath edge of electronegative dusty plasmas theoretically, using the standard fluid model for the sheath and treating electrons and negative ions as Boltzmann particles but positive ions and dust grains as cold fluids. The dust charging model is self-consistently coupled with the sheath formation criterion by the dust surface potential and the ion Mach number, moreover the dust density variation is taken into account. The numerical results reveal that the dust number density and negative ion number density as well as its temperature can significantly affect the dust surface potential at the sheath edge.     

Ion-induced electrostatic charging of ice

We studied electrostatic charging on amorphous ice films induced by the impact of 100 keV Ar⁺ ions at 45° incidence. We derived the positive surface electrostatic potential from the kinetic energy of sputtered molecular ions. Measurements were performed as a function of film thickness, ion flux and accumulated fluence. The main results are (a) films charge up to a saturation value, following an exponential time dependence. (b) The time constant for charging is approximately proportional to the reciprocal of the ion flux. (c) The maximum surface voltage depends on film thickness and ion flux. (d) Charging does not occur for films thinner than the maximum range of projectile. (e) Dielectric breakdown is observed for surface potentials above ∼100 V. We explain the measurements with a model in which charges can drift into the substrate or be trapped temporarily near the ionization range of the projectiles. A charge can be released from the trap by the electric field produced by a nearby charge injected by subsequent projectiles.     

Radiation Damage to Satellite Electronic Systems

Space radiation can cause damage to satellite electronic systems. The amount of damage can be determined if the radiation induced component changes are known and if the behavior of the electronic system as a function of component changes can be determined. By relating space radiation damage to neutron damage, a large amount of semiconductor device data becomes available for satellite damage predictions. To obtain circuit and system performance from component performance in an economical way analysis is combined with experimental techniques. The experimental technique involves substitution of radiation degraded components into the circuit and measurement of its performance. The application of such techniques to satellite electronics indicates that performance degradation caused by lifetime reduction resulting from space radiation can generally be kept small, particularly, if modern high frequency transistors are used. However, ionization of the semiconductor environment from the artificial electron belt may cause significant surface effects resulting in a reduction in device performance even for shielding of several gm/cm2.     

Dynamic characteristics of charging effects on the dielectric constant due to E-beam irradiation: a numerical simulation

A series of synthetic variations of material intrinsic properties always come with charging phenomena due to electron beam irradiation.The effects of charging on the dielectric constant will influence the charging dynamic in return.In this paper,we propose a numerical simulation for investigating the dynamic characteristics of charging effects on the dielectric constant due to electron beam irradiation.The scattering process between electrons and atoms is calculated considering elastic and inelastic collisions via the Rutherford model and the fast secondary electron model,respectively.Internal charge drift due to E-field,density gradient caused diffusion,charges trap by material defect,free electron and hole neutralization,and variation in the internal dielectric constant are considered when simulating the transport process.The dynamics of electron and hole distributions and charging states are demonstrated during E-beam irradiation.As a function of material nonlinear susceptibility and primary energy,the dynamics of charging states and dielectric constants are then presented in the charging process.It is found that the variation in the internal dielectric constant is more with respect to the depth and irradiation time.Material with a larger nonlinear susceptibility corresponds a faster charging enhancement.In addition,the effective dielectric constant and the surface potential have a linear relationship in the charging balance.Nevertheless,with shrinking charging affect range,the situation with a higher energy primary electron comes with less dielectric constant variation.The proposed numerical simulation mode of the charging process and the results presented in this study offer a comprehensive insight into the complicated charging phenomena in electron irradiation related fields.