Results 41 to 50 of about 12,003 (193)

氧化锌压敏电阻在直流环境下的老化机理研究

open access: yesDianci bileiqi, 2018
针对氧化锌压敏电阻直流作用下的老化问题。利用氧化锌压敏电阻肖特基势垒理论,对氧化锌压敏电阻在正极性和正、负极性直流交替作用下,氧化锌压敏电阻老化规律进行研究,得出以下结论:1)氧化锌压敏电阻在单一极性直流作用下,产生明显的极性效应。此外,极性效应和老化程度均随电流的增加而增大,当达到最高点时,出现减慢的现象。2)正、负极性电流交替作用时,ZnO压敏电阻出现极性补偿现象,使得肖特基势垒高度下降变慢,导致压敏电阻老化程度较单一极性电流作用下缓慢。
苑吉河   +4 more
doaj  

一种具备故障自清除能力的MMC新型双子模块拓扑研究

open access: yesGaoya dianqi, 2021
在多端柔性直流电网中,直流故障快速隔离和清除能力是系统可靠安全运行的保障。直流故障清除能力是制约基于半桥模块MMC发展的关键问题。文中提出了一种新型二极管箝位双子模块拓扑结构,在两个单子模块串联的基础上,增加了一个IGBT和一个二极管,利用子模块电容电压迫使导通的二极管反向截止,从而有效抑制MMC的不控整流效应,快速切断故障电流通路,具备直流故障自消除能力,具有很好的经济性和应用价值。
孙银山, 杨晓平, 任军辉
doaj  

Interfacial Electronic Interactions in Hierarchical Heterostructure Electrocatalyst for Energy‐Saving Hydrogen Production at Industrial Current Densities

open access: yesRare Metals, EarlyView.
ABSTRACT Developing low‐energy‐input electrocatalytic systems for efficient hydrogen production is crucial for advancing sustainable energy technologies. The overall hydrazine splitting (OHzS) has emerged as a promising strategy to reduce the overall energy consumption by replacing the sluggish oxygen evolution reaction.
Haozhou Chen   +13 more
wiley   +1 more source

积极心理对慢性耳鸣患者情绪困扰的影响

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 2018
【目的】探讨心理弹性及自尊两个积极心理因素在缓解慢性耳鸣患者情绪困扰中的作用,为耳鸣的临床管理提供新思路。【方法】通过心理弹性量表、自尊量表及抑郁-焦虑-压力简表了解慢性耳鸣患者的心理弹性、自尊、抑郁、焦虑及压力水平,再运用SPSS 24.0对入组的124名受试的数据进行相关分析及中介效应分析,最后运用AMOS 24.0进行结构方程模型验证。【结果】①绝大部分患者并无严重的情绪困扰,心理弹性、自尊、抑郁、焦虑及压力均无显著的性别间差异(P > 0.05);②心理弹性、自尊与抑郁 ...
戚敏   +6 more
doaj  

基于去极化电流Prony拟合的油纸绝缘德拜参数辨识方法

open access: yesGaoya dianqi, 2020
提出一种利用自适应采样间隔Prony算法对去极化电流数据进行拟合,进而辨识出徳拜等效电路参数的方法。根据扩展德拜等效模型下去极化电流指数函数叠加的物理性质,对传统单采样间隔Prony算法进行改进:根据不同大小时间常数去极化电流子谱线的衰减特性实现采样间隔的自适应选择,利用自适应采样间隔对去极化电流数据进行多次Prony拟合,得到相应时间常数的子谱线弛豫参数,进而辨识出油纸绝缘的徳拜电路参数;搭建扩展徳拜模型仿真平台得到PDC仿真数据进行拟合,验证了自适应采样间隔Prony算法对徳拜电路参数辨识的准确性 ...
高浩, 刘庆珍, 蔡金锭
doaj  

Carbon‐Insertion‐Engineered WS2 Hierarchical Heterostructure Enabling Superior Sodium‐Ion Storage

open access: yesRare Metals, EarlyView.
ABSTRACT Tungsten disulfide (WS2) is considered a promising anode material for sodium‐ion batteries (SIBs). However, its practical application is hindered by poor electrical conductivity, large volume changes during cycling, and sluggish ion diffusion kinetics, which lead to unsatisfactory electrochemical performance.
Xiuli Hu   +9 more
wiley   +1 more source

同轴结构电极边缘效应的仿真研究

open access: yesGaoya dianqi, 2006
同轴结构电极在高脉冲功率装置中广泛存在。利用ANSYS有限元数值计算软件包仿真计算内电极直径、闪络距离、固体介电常数等参数变化时对同轴空间电位(电场)的影响;与解析解比较,确定同轴电极边缘效应的变化趋势,得到同轴电极边缘效应不影响固体表面闪络特性的电极有效长度;给出一定内电极直径范围内的最小电极长度与内电极直径、闪络距离之间的参考关系式,对同轴电场下闪络特性的实验研究有着重要的指导意义。
黄文力, 孙广生, 李光杰
doaj  

Multifunctionality of Magnetic La(Fe, Si/Al)13‐Based Materials: Negative Thermal Expansion and Magnetocaloric Effect

open access: yesRare Metals, EarlyView.
ABSTRACT In recent years, the field of magnetic materials has witnessed a paradigm shift from single‐function applications to multifunctional integration, driven by the growing demand for smart materials in advanced technologies. Among various magnetic systems, La(Fe, Si/Al)13‐series materials have emerged as particularly promising candidates due to ...
Irfan Liaquat   +2 more
wiley   +1 more source

稍不均匀场下CF4/N2混合物雷电冲击绝缘特性研究

open access: yesGaoya dianqi, 2016
减少SF6温室气体的使用,对绿色电网有重要意义。目前对SF6替代气体的研究主要集中在常温环境下,对能够在极寒地区使用的替代气体研究还不多。CF4具有明显的电负性,同时液化温度较低。文中在稍不均匀电场下、正负两种极性雷电冲击作用下,研究了CF4及其N2混合物绝缘特性。研究结果表明:CF4/N2混合气体击穿电压随混合比增加有明显的饱和效应,20%混合气体具有较低液化温度和GWP指数,同时绝缘强度良好,具备在极寒地区使用的潜力;通过对混合气体的协同效应分析发现:CF4/N2混合气体协同效应随气压升高而变得明显,
李卫国   +3 more
doaj  

Electronic Modulation of Cu Sites via Iron Incorporation in Cu5FeS4 Bimetallic Sulfide for High‐Efficiency Oxygen Reduction Reaction

open access: yesRare Metals, EarlyView.
ABSTRACT The sluggish kinetics of the oxygen reduction reaction (ORR) necessitate developing oxygen electrodes with enhanced electrocatalytic activity for practical zinc–air battery applications. In this study, an iron‐doped copper sulfide electrocatalyst (CuFeNS‐PNC) anchored on metal–organic framework‐derived carbon substrates was designed, featuring
Taichong Chitboonyakasem   +4 more
wiley   +1 more source

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