Results 41 to 50 of about 29,284 (225)
Gaoya dianqi, 2017 电痕是引起绝缘表面劣化的主要原因之一。针对矿用乙丙橡胶电缆绝缘表面电痕腐蚀问题,文中以不同电痕发展阶段的乙丙橡胶试样为研究对象,试验测量并分析了乙丙橡胶表面电痕腐蚀程度与极化—去极化电流之间的关系,提取了去极化初始电流值、电流衰减稳定值和凹点出现时间3个特征量。对比不同电痕腐蚀程度试样的极化—去极化电流曲线及其特征量发现:在去极化初始阶段,初始电流值、放电速率和去极化电流衰减稳定时刻的电流值与乙丙橡胶表面电痕损伤程度密切相关;随着测量时间的延长,去极化电流曲线上出现凹点 ...
冯晨 +4 more
doaj
Æ E Æ Å – Reshaping the Role of Træna Fishermen
, 2022 This diploma project aims to strengthen the viability of Træna’s community by proposing an ocean research facility in the archipelago, enabling the next generation of local fishermen to collect oceanographic data while working at sea. The idea of the fisherman as oceanographer is inextricably linked to the architectural program on the island of ...
openaire +1 more source
Research and Design of High Isolation multipolarization MIMO Antennas [PDF]
, 2015 无线通信行业的蓬勃发展带来了频谱资源的日趋短缺，在现有的频谱资源上提高通信系统的传输速率和传输质量成为通信领域的研究重点。MIMO（Multiple-InputMultiple-Output，多入多出）可以在不增加发射功率和传输带宽的前提下，显著地提高系统的信道容量和频谱利用率，MIMO技术被认为是新一代无线通信系统中的革命性技术。当前，天线问题是限制MIMO技术发展的最大障碍之一。 本文在介绍MIMO天线的研究背景和意义，以及综述近年来国内外MIMO天线发展现状的基础上 ...
张斌
core
Striking a balance: Stakeholder perceptions of risk in horse racing
Equine Veterinary Journal, Volume 58, Issue 3, Page 814-823, May 2026.Abstract Background Thoroughbred racing is a major industry, and in recent years public concerns about equine safety have become more prominent, particularly in relation to on‐track injuries and fatalities. This has challenged the industry's social licence to operate (SLO).
Jessie McCarthy +2 more
wiley +1 more source
Dianci bileiqi, 2018 针对ZnO压敏电阻在直流电压作用下老化劣化的问题,通过对ZnO压敏电阻内部离子迁移和晶界肖特基势垒的理论分析。采用ZnO压敏电阻正极性直流作用和负极性直流交替作用的试验方法。利用理论与试验相结合,得出以下结论:1)老化前压敏电阻正、负极性伏安特性曲线几乎一致,没有产生极性效应;2)在单一正极性直流作用下,压敏电阻发生老化,且随时间和电流的增加,正极性老化程度大于负极性;3)在正、负极性直流交替作用下,压敏电阻老化时间推迟,程度减小,压敏电压和漏电流变化趋势较单一正极性趋势减弱,且极性效应趋于消失;4 ...
李祥超, 马骁骐
doaj
Evolution of Domain Structures of Epitaxial Ferroelectric Film under Different Electrical Boundary Conditions [PDF]
, 2015 本文采用基于金茨堡—朗道—德文希尔唯象理论的相场法，研究二维铁电薄膜畴结构的演化，并采用有限差分方法数值求解相场方程。首次提出了中间电学边界条件及其两类参数，并研究三种电学边界条件（中间电学边界条件、开路电学边界条件及短路电学边界条件）下铁电薄膜的畴结构及铁电性能。 结果显示，开路电学边界条件和短路电学边界条件下，薄膜畴结构有明显的尺寸效应。开路电学边界条件下，薄膜厚度较小时出现水平单畴结构；在临界厚度14nm处发生了水平单畴结构向多漩涡畴结构的转变；随厚度进一步增加，为了降低去极化电场能 ...
吴登阳
core
Focusing Events, Agenda Setting, and Narrative Numbing
Review of Policy Research, Volume 43, Issue 3, May 2026.ABSTRACT Focusing events are important in understanding policy change, as demonstrated in Birkland's work on agenda setting, the multiple streams framework, and the narrative policy framework. These frameworks emphasize the role of focusing events in drawing public attention to broader issues.
Megan K. Warnement Wrobel +1 more
wiley +1 more source
Gaoya dianqi, 2015 基于介质响应理论的回复电压法能够有效并无损地诊断变压器的绝缘状态。而变压器油纸绝缘极化等效电路模型特别是其中的参数计算在诊断研究过程中起到了关键作用。目前普遍采用的扩展德拜模型存在着极化支路数无法确定的问题,笔者针对此问题对极化支路数进行了探讨,对搭建的已知扩展德拜模型进行不同极化支路数求解,并根据绝缘状态越差极化支路数越多,假设绝缘状态差的变压器极化支路数为7条,绝缘状态良好的变压器极化支路数为5条。通过上述求解,探讨了极化支路数之间的关系,提出了支路试探法。并结合支路试探法 ...
彭积城, 蔡金锭
doaj
Mechanism research and far/near field application of asymmetric light reflectance based on LSP [PDF]
, 2016 随着信息化社会的迅速发展，人们对信息存储容量和传递效率的要求也日益提高。而局域表面等离子体(LSPs)由于具有独特的激发、传播以及局域场增强的特性，使其在光电子器件的微型化和集成化上有显著的优势，应用领域涉及太阳能电池、光电探测器、LED、荧光增强、表面增强拉曼散射、环境传感器、纳米激光器、纳米天线等。我们可以通过改变金属纳米结构的大小、形状以及周围介质环境等因素，在纳米尺度上实现光学信号的有效调控。在绝大多数应用中，LSPs均存在于空气/介质或介质/介质的界面处，因此 ...
潘伟
core
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT Eutectic high‐entropy alloys (EHEAs) have attracted significant attention due to their balanced mechanical properties and promising applications. Nonetheless, the correlation between the solidification mechanism of eutectic microstructures and their mechanical properties remains elusive.
Yi Qin +15 more
wiley +1 more source