Results 41 to 50 of about 787,391 (176)

变压器内典型油纸绝缘缺陷的高频局部放电传播特性研究

open access: yesGaoya dianqi, 2018
基于高频法检测局部放电技术已经相对成熟,为了现场检测和对变压器运行状况做出准确诊断,文中提出了利用高频法检测分析放电信号传播特性的方法。通过建立仿真模型确定了频带选择范围,并建立试验平台,利用多传感器同时测量和采集实时信号,对比研究了局部放电在变压器内部传播后以及在不同位置放电时高频信号的频谱特性。结果表明,高频局部放电检测法能够对变压器缺陷进行高效检测且高频信号变化规律明显,为实际的波形检测提供了试验依据。
王新, 苏欢欢, 高树国, 张鹏
doaj  

Ultralight N‐Doped Interconnected Porous Carbon From Lignin: Synergistic Structural and Doping Engineering for High‐Performance Electromagnetic Wave Absorption

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT The development of lightweight, high‐attenuation, and broadband carbon‐based electromagnetic wave absorbers is hindered by the intrinsic trade‐off between impedance matching and dielectric dissipation. Herein, we report a facile and scalable synthesis of N‐doped lignin‐derived interconnected porous carbon (Nx‐LIPC) via hydrogen‐bond self ...
Bin‐Peng Zhang   +7 more
wiley   +1 more source

滴灌频率和施氮量对温室西葫芦土壤水分、硝态氮分布及产量的影响

open access: yesShuitu Baochi Xuebao, 2018
2016年和2017年在北方寒旱地区日光温室西葫芦栽培中,灌溉定额为269.87 mm,设置2个滴灌频率(低频W1:7天1次,高频W2:2天1次)和2个氮素水平(适氮N1:375 kg/hm2,高氮N2:565 kg/hm2),研究不同处理对温室西葫芦土壤水分、硝态氮分布及西葫芦产量的影响。结果表明:(1)高频(W2)滴灌提高了0—40 cm土层的土壤水分,减少了水分的深层下渗。(2)高氮(N2)施肥各土层硝态氮含量较高,适氮处理配合高频次滴灌根区0—40 cm硝态氮含量维持在相对适宜水平,40—80 ...
郭鹏飞   +4 more
doaj  

Synergistic Modulation of Magnetic and Dielectric Properties via La‐V Co‐Substitution in Barium Hexaferrite for Advanced Millimeter‐Wave Absorption

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT The growing deployment of high‐frequency electronic systems has intensified the demand for high‐performance microwave absorption materials. In this work, we developed La‐V co‐substituted barium hexaferrites, Ba1‐xLaxFe11.9V0.1O19 (BLFVO), via a sol‐gel route.
Zhihui Yang   +7 more
wiley   +1 more source

高频感应放电的理论分析 [PDF]

open access: yes, 1981
本文利用拟渠道模型得到简明的分析表达式,求出了放电特性曲线;定义了高频振荡器的输出特性曲线,并作了计算;且由槽路参数将上述两曲线联系起来,定出工作点。为此可预先对任一种气体及高频机判断放电能否维持;可以讨论对工程实践至关重要的阻抗匹配问题以及功率放大规律 ...
陈允明
core  

Enhancement of Corrosion and Wear Resistance in Polymeric Coatings via Ce(III)‐Functionalized Ternary ZnAlCe Layered Double Hydroxides Intercalated With EDTMP

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT The intricate corrosion environment necessitates the polymeric coating's adaptability to the surroundings. In this work, the integration of rare‐earth Ce(III) ions and ethylene diamine tetramethylene phosphonic acid (EDTMP) in a layered double hydroxide (LDH) material is developed to enhance the corrosion protection and anti‐wear properties of
Yangu Liu   +9 more
wiley   +1 more source

利用频率叠加的方法实现高重频高压窄脉冲源

open access: yes, 2011
利用传统方法实现高重频高压窄脉冲源受制于的器件性能,因而 提出了频率叠加的新思路。基于超快电子学和频率叠加理论,利用MARX电路产生多路高压窄脉冲,通过同步系统控制多路触发信号延时,使多路脉冲耦合成一路 输出,实现高重频高压窄脉冲输出。实验中两个单路高压窄脉冲的幅度为2.56 kV,宽度为7.13 ns,重复频率为32 kHz,两路脉冲耦合后,输出脉冲幅度为2.46 kV,宽度为7.49 ns,重复频率为64 kHz。该实验验证了设计思路的可行性,实现了输出脉冲重复频率倍增 ...
阮驰   +5 more
core  

Boosting Thermoelectric Properties of BiSbSe3 Through Ag‐Induced Interstitial Occupancy and Multi‐Phase Microstructure

open access: yesRare Metals, Volume 45, Issue 6, June 2026.
ABSTRACT Te‐free BiSbSe3 is a promising medium‐temperature thermoelectric (TE) material owing to its cost‐effectiveness and intrinsically low lattice thermal conductivity. However, its comparatively low electrical conductivity has severely hindered the optimization of TE performance.
Xiaowei Shi   +10 more
wiley   +1 more source

用于高速目标测量的大视场高帧频系统及方法

open access: yes, 2013
本发明提出了一种用于高速目标测量的大视场高帧频系统,包括依次连接的前端成像单元、FPGA逻辑控制电路单元、DSP信号处理电路单元以及供电电路,供电电路分别与前端成像单元、FPGA逻辑控制电路单元、DSP信号处理电路单元连接。本发明用于高速目标测量的大视场高帧频系统及方法,用于高速目标捕获跟踪系统 ...
李瑛   +5 more
core  

高频电压下油纸绝缘系统的局部放电及产气特性研究

open access: yesGaoya dianqi, 2018
高频变压器在提升电能传输效率的同时,也会加速油纸绝缘系统缺陷的劣化进程。为研究油纸绝缘系统在高频电压下的劣化特性,采用柱板模型模拟油纸绝缘的沿面放电缺陷,搭建高频局部放电试验平台,在10、20、30 k Hz电压下采用恒压法进行多组局部放电试验。利用摄像机和罗氏线圈分别记录试验现象和放电信号,分析高频电压下局部放电图谱和产气特性,并与工频局部放电试验的结果进行对比。结果表明:随着频率的提高,油纸绝缘系统的局部放电起始电压显著降低,单位时间内关键气体的产气量明显提高;但在高频电压下 ...
刘思华   +5 more
doaj  

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