Results 11 to 20 of about 165,790 (164)
Gaoya dianqi, 2023 文中针对高压开关温升预测缺少电流同温升关系模型这一难点，首次建立导电部位稳定温升τw与电流I的数学模型，得出τw与I的变化规律，通过高压开关柜系列电流下的温升试验，验证了该模型的合理性和准确性。阐述了电器发热基本理论中温升τ与时间t关系模型的推导过程，通过高压开关柜系列电流下的温升试验，进一步研究了该模型下不同试验时间段的拟合温升规律。在温升预测应用中，按文中τw与I的数学模型，求解形成稳定温升与电流标准曲线，作为温度在线监测的判断标准，从而实现故障提前预警。
兰剑, 韩冬, 冯英, 陆德鹏
doaj
Dianci bileiqi, 2021 局部异常温升会对复合绝缘子的绝缘性能造成不可逆转的伤害,严重威胁电网的安全运行,近年来复合绝缘子异常温升缺陷逐渐凸显且呈现越来越严重的趋势。针对±800 kV楚穗直流输电线路在线运行复合绝缘子的异常温升情况,利用红外测温技术和扫描电子显微镜法对复合绝缘子异常温升缺陷进行全面深入研究,发现造成楚穗直流线路复合绝缘子异常温升的主导原因为绝缘子的内部缺陷。依据复合绝缘子局部异常温升的不同形态将其划分成不同温升类型,在研究复合绝缘子局部异常温升状态、温升类型与缺陷等级关系的基础上 ...
郑武略 +4 more
doaj
Gaoya dianqi, 2020 为了验证晶闸管可否承受设计要求的最高结温及高低温循环应力,在出厂试验阶段需要开展换流阀温升试验。首先介绍了温升试验参数的计算方法,其次设计了采用直流电流加热原理的温升试验回路,最后结合某换流阀实例计算了温升试验参数,在试验室中开展了温升试验。试验结果显示温升试验参数的试验值和计算值基本一致,试验前后晶闸管性能未有下降。试验结果表明,结合给出的温升试验参数计算方法和温升试验回路可以完成温升试验,验证晶闸管的温升性能。
张翔 +5 more
doaj
Jianzhu Gangjiegou Jinzhan, 2021 采用有限元软件ABAQUS建立了用于模拟预应力组合梁在火灾下全过程受力行为的模型,研究拉索防火涂层对预应力连续组合梁抗火性能的影响。考察组合梁跨中挠度、拉索应力及塑性应变随温度的变化,分析了预应力组合梁在高温下的温度变化和破坏模式。结果表明:钢梁下翼缘与腹板升温较快,二者温差很小,而腹板与上翼缘的温差较大;混凝土截面各测点处升温速率由下至上依次降低,上表面与下表面的最高温度差可达约700℃;当拉索有5 mm厚防火涂层时,在升温前期其温度随时间延长而上升的幅度比无防火层时温度上升的幅度要小,同一升温时间下,
周焕廷 +5 more
doaj
Dianci bileiqi, 2022 近年复合绝缘子酥朽故障引起的温升现象逐步增多，是复合绝缘子应用面临的主要故障类型。然而除芯棒酥朽缺陷外，引起复合绝缘子温升的成因还包括绝缘子表面积污放电、护套吸水受潮、阳光不均匀直射等原因。本研究收集不同温升类型复合绝缘子的红外图谱，并统计其温升的部位分布特点、温升数值等红外特征。其次，基于有限元分析和检测试验，分析各温升现象的成因和机理。最后基于现场统计分析的红外图谱特征、检测试验和仿真分析，总结温升缺陷复合绝缘子温升特点及其识别规则，为现场复合绝缘子红外测温诊断提供了理论指导。
王晓杰 +4 more
doaj
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Soil organic nitrogen (SON) transformation is critical for global nutrient cycling and ecosystem productivity, yet how its responsiveness to climate change differs across diverse land use types remains poorly resolved.
Xinyi Yang +10 more
wiley +1 more source
Habitat and spatial trends of U.K. wintering waterbird populations over 50 years
Conservation Biology, EarlyView.Abstract The United Kingdom is an important wintering ground for millions of waterbirds. Most U.K. wintering waterbird populations increased between 1970 and the mid‐1990s, but declined thereafter. We examined U.K. population indices in 46 wintering waterbird species in two 25‐year periods, 1970–1994 and 1995–2019, to identify which waterbird groups ...
Blaise Martay +8 more
wiley +1 more source
Uncovering correlates of decline and critical refuges for a threatened terrestrial mammal
Conservation Biology, EarlyView.Abstract Globally, the geographic ranges of numerous species are contracting. Identifying spatiotemporal patterns of threat impact can illuminate why species decline in some parts of their range but persist in others. We developed a correlative approach to identify species’ response thresholds and locate ecological refuge areas associated with ...
Natalya M. Maitz +5 more
wiley +1 more source
Rare Metals, Volume 45, Issue 6, June 2026.ABSTRACT Near‐infrared (NIR) phosphors with broadband and efficient emission are pivotal for the performance of NIR phosphor‐converted light emitting diodes (pc‐LEDs). In this study, the double perovskite phosphor La2MgTiO6:Cr3+ phosphor with broadband emission in the range of 650–950 nm was prepared.
Xu Qian +7 more
wiley +1 more source
Rare Metals, Volume 45, Issue 6, June 2026.ABSTRACT Improving catalytic activity for volatile organic compounds (VOCs) oxidation and enhancing water‐tolerance stability remain challenging in practical applications. Herein, a composite catalyst integrating Pt/CoOx‐NiOx mesoporous nanorods (MNRs) with a phenyltriethoxysilane (PhTES)‐modified surface was fabricated via a facile route for toluene ...
Jiaqin He +13 more
wiley +1 more source