Bio-Inspired Electromagnetic Protection Based on Neural Information Processing

Electronic systems are vulnerable in electromagnetic interference environment. Although many solutions are adopted to solve this problem, for example shielding, filtering and grounding, noise is still introduced into the circuit inevitably. What impresses us is the biological nervous system with a vital property of robustness in noisy environment. Some mechanisms, such as neuron population coding, degeneracy and parallel distributed processing, are believed to partly explain how the nervous system counters the noise and component failure. This paper proposes a novel concept of bio-inspired electromagnetic protec- tion making reference to the characteristic of neural information processing. A bionic model is presented here to mimic neuron populations to transform the input signal into neural pulse signal. In the proposed model, neuron provides a dynamic feedback to the adjacent one according to the concept of synaptic plasticity. A simple neural circuitry is designed to verify the rationality of the bio-inspired model for electromagnetic protection. The experiment results display that bio-inspired electromagnetic pro- tection model has more power to counter the interference and component failure.

Bio-Inspired Microwave Modulator for High-Temperature Electromagnetic Protection,Infrared Stealth and Operating Temperature Monitoring

High-temperature electromagnetic(EM) protection materials integrated of multiple EM protection mechanisms and functions are regarded as desirable candidates for solving EM interference over a wide temperature range.In this work,a novel microwave modulator is fabricated by introducing carbonyl iron particles(CIP)/resin into channels of carbonized wood(C-wood).Innovatively,the spaced arrangement of two microwave absorbents not only achieves a synergistic enhancement of magnetic and dielectric losses,but also breaks the translational invariance of EM characteristics in the horizontal direction to obtain multiple phase discontinuities in the frequency range of 8.2-18.0 GHz achieving modulation of reflected wave radiation direction.Accordingly,CIP/C-wood microwave modulator demonstrates the maximum effective bandwidth of 5.2 GHz and the maximum EM protection efficiency over 97% with a thickness of only 1.5 mm in the temperature range 298-673 K.Besides,CIP/C-wood microwave modulator shows stable and low thermal conductivities,as well as monotonic electrical conductivity-temperature characteristics,therefore it can also achieve thermal infrared stealth and working temperature monitoring in wide temperature ranges.This work provides an inspiration for the design of high-temperature EM protection materials with multiple EM protection mechanisms and functions.

Effect and mechanism of on-chip electrostatic discharge protection circuit under fast rising time electromagnetic pulse

The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with the CMOS circuit,but also acts on the protection circuit.This paper establishes a model of on-chip CMOS electrostatic discharge protection circuit and selects square pulse as the FREMP signals.Based on multiple physical parameter models,it depicts the distribution of the lattice temperature,current density,and electric field intensity inside the device.At the same time,this paper explores the changes of the internal devices in the circuit under the injection of fast rising time electromagnetic pulse and describes the relationship between the damage amplitude threshold and the pulse width.The results show that the ESD protection circuit has potential damage risk,and the injection of FREMP leads to irreversible heat loss inside the circuit.In addition,pulse signals with different attributes will change the damage threshold of the circuit.These results provide an important reference for further evaluation of the influence of electromagnetic environment on the chip,which is helpful to carry out the reliability enhancement research of ESD protection circuit.

Multiple Tin Compounds Modified Carbon Fibers to Construct Heterogeneous Interfaces for Corrosion Prevention and Electromagnetic Wave Absorption

Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent.Multi-component interface engineering is considered an effective means to achieve high-efficiency EMW absorption.However,interface modulation engineering has not been fully discussed and has great potential in the field of EMW absorption.In this study,multi-component tin compound fiber composites based on carbon fiber(CF)substrate were prepared by electrospinning,hydrothermal synthesis,and high-temperature thermal reduction.By utilizing the different properties of different substances,rich heterogeneous interfaces are constructed.This effectively promotes charge transfer and enhances interfacial polarization and conduction loss.The prepared SnS/SnS_(2)/SnO_(2)/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt%in epoxy resin.The minimum reflection loss(RL)is−46.74 dB and the maximum effective absorption bandwidth is 5.28 GHz.Moreover,SnS/SnS_(2)/SnO_(2)/CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel surfaces.Therefore,this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.

Principles of electromagnetic protection bionics and research of fault self-recovery mechanism

As we have borrowed the wisdom from biological neural network, the characteristic of interference- proof in information transferring process has been carefully studied. Our study includes the response of electrical-interference-proof circuit in electromagnetic environment, by means of bionics redesign. In this way, new principles, new technics and new ways are adopted to solve the unavoidable situations in traditional electro- magnet protection design. Based on the Boolean model, the complex bionic topological networks were firstly built and the charactoristics of degeneracy were analyzed, then the bidirectional actions between degeneracy in networks and the robustness of functions were proved in order to fill up the gap to deal with the need of interference-proof. Based on the creation of the neuron networks and the electrical synapses ＇ charac- teristic of plasticity, the impact of the distribution in the weight of synapse on the character of network self- recovery was studied afterwards so that the corresponding mechanism could be defined.

Research on Technology of Electromagnetic Protection for the Generator Control System

Generator control system decides whether the generator can work as usual or not, as well as its stability of performance. Both types of generators control system composed of the transistor and DSP are sensitive to outward electromagnetic interference, directly related to the generator performance. In this text, we first analyze the electromagnetic interference threat generator control system of transistor type may face, then design a electromagnetic protection plan for the intake, the panel and the sense organ. This work is of great significance in improving its electromagnetic protection ability and stability of performance.

Protective effects of blueberry anthocyanin extracts on hippocampal neuron damage induced by extremely low-frequency electromagnetic field

The protective effects of blueberry anthocyanin extracts against damage induced by extremely lowfrequency electromagnetic field(ELF-EMF)were investigated in a rat model.Wistar rats were exposed to ELF-EMF with or without the administration of blueberry anthocyanin extracts(50,100,and 200 mg/kg per day intragastrically once a day)for 30 days.Blueberry anthocyanin extracts supplementation inhibited the decrease in Nissl substance levels,cell membrane integrity,and mitochondrial membrane potential induced by ELF-EMF;prevented the increase in nitric oxide,malondialdehyde,and Ca2+concentrations;suppressed superoxide dismutase and glutathione depletion;and enhanced the cognitive ability of the rats exposed to ELF-EMF.The protective effects of blueberry anthocyanin extracts against hippocampal neuron injury caused by ELF-EMF were dose-dependent.These results demonstrated that blueberry anthocyanin extracts suppress hippocampal neuron injury caused by ELF-EMF by inhibiting cell membrane damage and oxidative stress pathways,and suggested that blueberry anthocyanin treatment potentially prevents hippocampal neuron injury.

一种宽带吸波型电磁脉冲防护器件设计

在复杂电磁对抗环境中,对电子信息装备射频前端采取电磁防护措施以抵御强电磁干扰甚至损伤是必要的。针对现有防护器件在工作时反射超过阈值的强干扰信号,容易造成二次电磁威胁的问题,提出一种宽带吸波型电磁脉冲防护器件设计。通过在防护主路上引入微带线匹配枝节,实现电磁脉冲信号与输出端口隔离的同时,将其传输至匹配负载进行宽带吸收。在0.5 GHz至1.5 GHz(相对带宽>90%)内,实现了对低功率信号插入损耗小于1 dB,对电磁脉冲信号防护隔离度大于10 dB,同时输入端口回波损耗大于10 dB的良好性能。

The Effects of Bio-inspired Electromagnetic Fields on Normal and Cancer Cells

The electromagnetic field(EMF)is one of many environmental factors,which earth creatures are exposed to.There are many reports on the effects of EMF on living organisms.However,since the mechanism has not yet been fiilly understood,the biological effects of EMF are still controversial.In order to explore the effects of bio-inspired EMF(BIEMF)on normal and cancer cells,various cultured cells have been exposed to BIEMF of different directions,i.e.vertical,parallel and inclined.Significantly reduced ATP production in Hela and A549 cancer cells is found for the parallel and vertical BIEMF.More careful examination on Hela cells has revealed a cell density dependent inhibition on colony formation.The morphological observation of BIEMF-exposed Hela cells has suggested that the retarded cell proli feration is probably caused by cell death via apoptosis.Together these results may afford new insights for cancer prevention and treatment.

Influences of 500 kV Transmission Lines on Wetland Ecosystem and Its Protective Countermeasures--A Case Study of the Lake Wetland Natural Reserve along the Yangtze River in Anqing City

The impact of 500 kV transmission lines of Anqing power plant across the lake wetland reserve along the Yangtze River on the safety of the ecosystem was taken as the researched object.The power frequency electric field intensity(PFEFI),power frequency magnetic field intensity(PFMFI),radio interference,construction noise,vegetation destruction and the influence on water quality were investigated and monitored,and the influences of PFEFI,PFMFI,radio interference and construction noise on wild animals,especially the habitats and migration of birds were mainly researched.The direct and indirect influences on the surrounding environment as well as plants and animals in sensitive areas were analyzed and predicted.The results firstly showed there existed a 182 400m^3 stereo-space(PFEFI>4kV/m)which made flying birds unsafe under the lowest height 11 mof the lines,which fills the gap in the research of this field.Finally,some operational protection countermeasures were put forward at the current technical level to achieve the win-win goal of economic development and natural protection.

电枢外置线圈感应型电磁发射器磁场分布与运动特性

为强化线圈感应型弹射器对弹射体外形的适应性,提升弹射器的空间利用率,提出了电枢外置式线圈感应型电磁发射器,建立了6组不同条件的发射器模型,通过数值计算求解驱动线圈的磁场分布,通过静态有限元仿真计算驱动线圈和电枢的耦合情况,理论分析了电枢的受力情况,进行了瞬态有限元仿真验证,研究了驱动线圈内径和电枢相对位置对发射器的影响。磁场计算结果表明,驱动线圈内部径向磁感应强度与外部径向磁感应强度近似相等,外置电枢包围的轴向磁通为5.51×10^(-5)~22.04×10^(-5)Wb,内置电枢包围的轴向磁通为2.81×10^(-5)~17.39×10^(-5)Wb,驱动线圈外部的磁感应强度峰值为5.38×10^(-3)~7.32×10^(-3)T,内部磁感应强度峰值为1.57×10^(-2)~1.93×10^(-2)T。静态有限元仿真结果显示,外置电枢与驱动线圈的互感和互感梯度大于内置电枢约1.5倍~3倍。瞬态有限元仿真结果表明,内置结构的效率为2.96%~17.57%,外置结构的效率为4.94%~19.76%。证明了外置电枢包围的磁通约为内置电枢包围磁通的1.27倍~1.96倍,因此在径向磁感应强度接近的情况下,外置电枢可以获得更大的加速力;驱动线圈外部的磁感应强度大约是内部磁感应强度的1/3,因此外置结构具有更好的电磁防护能力;外置结构的能量转换效率比内置结构的效率高12.5%~66.6%,因此外置结构具有更高的能量转换效率。

航空发动机电子控制器的高强辐射场干扰及防护

针对航空发动机电子控制器(EEC)易受高强辐射场(HIRF)干扰问题,以ZF-M600型EEC为研究对象,通过三维电磁仿真软件CST对EEC建模并进行平面波辐照仿真,模拟HIRF对EEC的干扰效应,仿真结果表明,HIRF可以通过孔缝耦合进入EEC内部并在腔体内部产生谐振,谐振频率处电场强度显著增加。依据RTCA DO-160G在400 MHz~4 GHz开展EEC辐射敏感度试验,试验结果表明:EEC失效频点为2.40 GHz和3.48 GHz,敏感模块为模拟量输入输出模块,敏感现象为模拟量数据丢失。EEC失效频点与谐振频率接近,说明EEC失效与腔体谐振有关,在EEC内部贴装吸波材料并进行仿真,分析吸波材料的放置方式和厚度对EEC谐振电磁干扰强度的影响,仿真结果表明,贴装吸波材料可以有效抑制谐振电磁干扰。

能量选择电磁防护方法理论与应用

随着信息技术的发展,电磁空间逐渐成为国家重大公共基础设施及信息网络的基石。近年来,强电磁源生成技术加速发展,对电磁空间安全形成严重威胁,开展强电磁防护技术研究具有迫切的现实需求。能量选择防护方法是一种新型自适应强电磁防护方法,突破了电子设备前门防护“能防”和“兼容”的难题,为强电磁防护提供了新的技术思路。本文对能量选择防护方法进行了系统综述,首先详细介绍了能量选择防护的内涵和相关概念;其次以能量选择表面为例阐述了其工作原理与实现方式,在此基础上对能量选择防护方法的研究现状和最新成果进行介绍,梳理了能量选择防护方法的发展脉络;最后,对能量选择防护方法的未来研究方向进行了展望。

射电宁静天空保护进展

射电天文业务(radio astronomy service,RAS)通过探测来自宇宙的无线电信号开展天文研究。由于射电望远镜的高灵敏度,极易受到来自望远镜本身的电磁辐射,及移动通信业务和卫星业务等主动无线电业务射频干扰(radio frequency interference,RFI)的影响,因此保护射电宁静天空是支撑射电天文观测研究取得科学成果的重要基础。近期,国内射电天文设施发展迅速,如500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)已取得众多突出成果,新疆奇台110 m射电望远镜正在建设等。与此同时,主动无线电业务的快速增加,导致国内射电望远镜无线电环境逐渐恶化。为保护RAS所需的射电宁静天空,国内开展了相关的技术研究,并采取了频谱管理措施,如射电望远镜电磁兼容(electromagnetic compatibility,EMC)技术研发、评估RAS与主动无线电业务的兼容性、在射电望远镜周边设立电磁波宁静区(radio quiet zone,RQZ)、参与国际与国内频谱管理协调等,本文进行了总结陈述。这些工作,有效地保护了国内射电望远镜周边的电磁环境。

某型射频接收机强电磁耦合的仿真预测

针对强电磁环境下射频接收机仿真预测的问题,开展强电磁脉冲信号构建、射频接收机建模、场路结合方式预测等研究,得到射频接收机内部监测点场强、壳体表面电流、接收机线缆耦合电压等仿真结果,实现对某型射频接收机电磁防护的优化设计,为射频接收机强电磁防护实施提供支撑。

集成电路电磁兼容性分析方法及展望

文章给出了集成电路电磁兼容性的含义和需要研究的内容,简单介绍了集成电路电磁兼容性分析所涉及的三种测试方法、四种建模方法以及防护方面的核心技术方向,给出了一些精准测试、准确建模、正向设计方法的案例参考。这些方法将为芯片供应商、产品研制单位提供基于集成电路电磁兼容性测试结果和模型的电磁防护正向设计方法的思路和建议,为芯片和产品的电磁可靠性提升提供发展方向。

高空电磁脉冲晚期环境下电力系统效应研究进展

高空电磁脉冲作为一种广域电磁攻击手段,能对电力设备造成较大冲击,甚至造成电力基础设施瘫痪,严重威胁新型电力系统安全。主要聚焦国内外高空电磁脉冲晚期环境下电力系统效应研究进展。首先,分析了高空电磁脉冲晚期环境下地磁扰动产生机理及感应地电场计算方法,建立了极端地磁感应电流的计算模型。其次,归纳了极端地磁感应电流注入情况下电力变压器、互感器、断路器等典型易损设备效应特征与机理。进一步地,分析了高空电磁脉冲晚期环境极下端地磁感应电流模拟注入装置和效应试验方法,总结了美国国防威胁降低局、美国电力研究院项目等相关试验和电力系统效应仿真与评估研究。最后,从高空电磁脉冲晚期环境效应机理、典型设备效应特征、模拟效应试验和系统级效应评估等层面总结了现有研究结论,梳理了下一步发展方向。

电磁轨道炮无线电引信综合电磁防护方法

电磁轨道炮发射时膛内瞬变强磁场环境会使无线电引信电路中产生感应电流,对引信正常工作产生影响,因此需要采取合理的电磁屏蔽和防护措施保证引信可靠工作。针对上述问题,基于法拉第电磁感应定律,提出电磁轨道炮无线电引信综合电磁防护方法,即利用高磁导率材料壳体进行磁屏蔽,降低引信电路的磁感应强度;利用高电导率材料的涡流效应降低引信电路中的磁感应强度变化率;通过优化电路设计,减小引信电路回路面积;通过电路板布局,减小引信电路与磁场的点乘。强磁场环境下无线电引信的有限元模型的仿真分析结果表明,上述电磁防护方法有效,所得研究结果能够为电磁轨道炮无线电引信设计提供参考。

半导体桥火工品的防静电与防射频设计

为提高半导体桥(SCB)火工品的防静电与防射频的双防能力,将静电加固器件瞬态电压抑制(TVS)二极管和射频加固器件负温度系数(NTC)热敏电阻同时集成入SCB火工品的结构中,并研究了上述组合器件对SCB火工品发火性能和抗电磁性能的影响规律。结果表明:集成防护器件后,SCB火工品的安全电流从1.2 A升至1.5 A;抗静电性能满足500 pF/500Ω/25 kV条件下不发火;在22μF/16 V的电容发火条件下,集成SCB火工品的平均爆发时间较SCB火工品增加了1.77μs。因此,该组合型防护器件可以在不改变SCB发火性能的基础上有效提高SCB的抗静电和抗射频的能力。