Results 1 to 10 of about 334 (104)

屏蔽线和三相线空间结构变化对雷击耦合电压的影响

open access: yesDianci bileiqi, 2021
基于多导线的Agrawal场-线耦合模型,采用"两步走"方法,从理论层面研究了屏蔽线和三相线路的空间结构变化对耦合电压峰值的影响。笔者从两个方面进行讨论:1)屏蔽线的高度对耦合电压的影响,其他条件不变,发现屏蔽线越高,相线受到的屏蔽效应呈现先增大后减小的趋势。线路结构两边的两根相线在屏蔽线高度为17.05 m时,屏蔽效应达到最大;但对中间的一根相线而言,屏蔽线高度为12.05 m时,屏蔽效应最大。2)保持屏蔽线和三相线的高度不变,通过改变三相线的水平距离(屏蔽线的水平间距也随之改变 ...
宁欣婷   +4 more
doaj  

开关柜工频磁场计算及壳体屏蔽效能分析

open access: yesGaoya dianqi, 2023
文中基于电磁场基本理论,建立了开关柜工频磁场数学模型,采用有限元法对开关柜的磁感应强度进行了计算,分析了壳体、壳体厚度和磁导率等对开关柜磁感应强度分布和屏蔽效能的影响,并研究了开关柜柜外母排长度对磁感应强度分布的影响,结果表明:开关柜外壳和隔板对工频磁场具有明显的屏蔽作用,增大壳体磁导率和厚度均可提高开关柜整体的屏蔽效能,但当壳体磁导率大于1 000和厚度超过3 mm时,屏蔽效能增长幅度较小;柜外母排长度对开关柜周围磁场分布影响较小,但对柜体顶部磁场分布的影响较大 ...
王岩   +4 more
doaj  

雷电电磁脉冲对风机机舱电磁环境的影响与防护研究

open access: yesDianci bileiqi, 2021
当风力发电机的机舱受到雷击时,机舱内会产生雷电电磁脉冲(LEMP),继而影响电子设备运行,甚至严重破坏电子设备。为了研究机舱内的LEMP,首先建立了非金属机舱的全尺寸模型。采用传输线矩阵法对机舱内雷电电磁环境进行了模拟分析。然后研究了在机舱上应用金属屏蔽网的防护措施,包括屏蔽网的网格尺寸和材质对防护效果的影响。结果表明,金属屏蔽网可以有效地降低机舱内的LEMP。屏蔽效果很大程度上取决于屏蔽网材料的导电性和网格尺寸。
周歧斌   +3 more
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基于仿真方法的铺设防雷金属网的CFRP电磁屏蔽特性分析

open access: yesDianci bileiqi, 2022
防雷金属网主要用于碳纤维复合材料(CFRP)蒙皮雷电直接效应的防护,同时金属网和CFRP共同对高强度辐射场(HIRF)产生屏蔽效果。通过有限元仿真的方法,提取铺设有防雷金属网的CFRP蒙皮单元进行精细建模,设计二端同轴传输线屏蔽模型,采用S参数计算屏蔽效能(SE)。计算分析在HIRF环境下,铺设有防雷金属网CFRP蒙皮的SE。结果表明:1)防雷金属网在较低频段有较好的SE,随着频率增大,孔缝效应导致SE明显下降。当信号超过800 MHz时,SE低于40 dB,40 G时SE仅为6 dB左右;2 ...
王昭, 杜哲, 段雁超, 张培培
doaj  

Coral‐Like Yolk–Shell‐Structured CoNi@Void@C Microspheres for Enhanced Microwave Absorption, Photothermal, Anti‐Corrosion, and Radiation Shielding Properties

open access: yesRare Metals, EarlyView.
ABSTRACT Considering the multiple challenges faced by stealth coatings in complex service environments, the development of multifunctional integrated microwave absorbing materials (MAMs) that combine efficient electromagnetic (EM) attenuation with environmental tolerance has become an urgent need. In this work, coral‐like CoNi@Void@C microparticle (MP)
Jiale Wu   +8 more
wiley   +1 more source

On the Damage Tolerance of Diffusion Bonded Titanium–Aluminum Phase Biomimetic Composites

open access: yesRare Metals, EarlyView.
ABSTRACT The biomimetic design principles of natural structures involve the strategic integration of stiff and compliant phases to synergistically enhance strength and toughness. Its evolutionary refined natural armor, characterized by a specialized microarchitecture, enables superior damage tolerance.
Shuai Tong   +10 more
wiley   +1 more source

Filling Uniformity of AgNPs in EMI Shielding Patch Regulated by Surface Morphology

open access: yesRare Metals, Volume 45, Issue 1, January 2026.
ABSTRACT Silver nanoparticles (AgNPs) are extensively employed for electromagnetic interference (EMI) shielding owing to their remarkable conductivity, and are commonly incorporated into polymer matrices. Therefore, the uniformity of the AgNP distribution within the polymer matrix is a crucial factor that affects the EMI shielding performance.
Jie Yang   +8 more
wiley   +1 more source

Comparative enhancement of H+ and OH− treatment on electromagnetic interference shielding in aligned and compact Ti3C2Tx MXene film

open access: yesRare Metals, Volume 44, Issue 3, Page 1833-1843, March 2025.
Graphical abstract AbstractThe pressing demand for ultrathin and flexible shields to counter electromagnetic interference (EMI) has sparked interest in Ti3C2Tx MXene materials due to their exceptional electrical conductivity, tunable surface chemistry, and layered structure.
Zhao‐Yang Li   +5 more
wiley   +1 more source

高压变电站工频电磁场屏蔽效能测试及分析

open access: yesGaoya dianqi, 2010
随着中国特高压电网的建设,对于特高压变电站内电磁环境的评估已经引起了相关部门的重视。为了保障工作人员的健康与安全,国内变电站工作人员在工作期间都穿有屏蔽服,减弱这种危害。为了评估高压变电站现有屏蔽措施的效能,根据国家的相关规范与标准,对500 kV变电站的电磁环境和目前的屏蔽措施进行了测试,分析了目前屏蔽措施的屏蔽效果,结果表明,目前变电站内的屏蔽服对工频电场的屏蔽效果较好,在测试模型的头部和胸部的屏蔽效能分别为39.4 dB和12 dB,但是对工频磁场的屏蔽效能较差,在相同的位置的屏蔽效能分别为0 ...
杨帆, 姚德贵, 彭卉, 何为
doaj  

特高压GIS复合套管局部放电的检测和消除

open access: yesGaoya dianqi, 2021
复合套管具有抗湿闪、防爆、重量轻和成本低的特点,在特高压GIS中得到了广泛应用。在特高压GIS复合套管的研制中,出现局部放电超标问题,文中通过对局部放电现象和规律的分析,以及局部放电定位,确定了局部放电发生在套管空心绝缘子对应于内部屏蔽系统的位置;通过电场分析,确定了屏蔽系统附近电场分布设计的缺陷导致了局部放电;通过改进屏蔽系统结构和优化电场分布,使得套管伞裙的最大场强从0.49 kV/mm减小到0.26 kV/mm,有效消除了局部放电,实现了良好的工程应用。
李旭   +9 more
doaj  

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