Results 21 to 30 of about 4,536 (118)
Gaoya dianqi, 2022 为研究热老化下介质直流和操作冲击结果的演变规律及其影响机制，文中以热老化处理的（190℃，220℃）双层聚酰亚胺薄膜（PI）为研究对象，采用等温松弛电流法（IRC）对不同热老化程度介质的空间电荷特性进行研究，基于双极性电荷输运模型（BCT），仿真研究陷阱密度对直流击穿结果的影响机制。基于局域态电荷吸收能量的频率依赖模型，数值分析空间电荷和介电参量对冲击击穿结果的影响机理。结果表明，随着热老化时间增加，介质陷阱密度逐渐减小，电荷注入效应增强，介质内部的电场畸变程度增大，故直流击穿场强逐渐下降 ...
梅冰笑 +4 more
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Journal of Ecology, Volume 113, Issue 7, Page 1746-1759, July 2025.In forests dominated by large clonal plants, such as giant moso bamboo, drought can alter the allocation of newly assimilated C within the tissues of source ramet but may not affect its allocation among interconnected ramets or within plant–soil systems.
Xiaogai Ge +9 more
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Equine Veterinary Journal, Volume 57, Issue 4, Page 1053-1064, July 2025.Abstract Background In Great Britain, owners are keeping their horses into increasingly older age, reflecting societal changes in human–animal relationships. The uptake of routine veterinary services is reported to reduce as horses age. Horse owners seek information regarding their animal's health from alternative sources before and/or following ...
Rebecca Smith +4 more
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Gaoya dianqi, 2018 为研究某500 kV变电站硅橡胶辅助伞裙粉化、脆化、塌陷甚至断裂脱落的原因,以此变电站的老化伞裙为研究对象,采用憎水性、机械性能测试,扫描电子显微镜、X射线光电子能谱、红外光谱、热失重分析等多种技术进行理化特性分析和老化评估。结果表明,相比于新伞裙,老化伞裙的憎水性、机械性能已大幅度退化。硅橡胶在外界环境作用下发生复杂的物理化学变化,分子链断链并生成了大量强极性活性基团,同时有机组分流失,形成微孔洞结构,使硅橡胶伞裙性能下降。伞裙配方不够合理也可能是较快劣化、性能下降的原因 ...
吴俊杰 +5 more
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Integrative Conservation, Volume 4, Issue 1, Page 85-94, March 2025.Chromolaena odorata and Ageratina adenophora are invasive species in Southern Yunnan, China; they have very differing, yet overlapping, climate niches. Both invaders produce a large number of small pappus‐bearing achenes every year. They grow in, and their seeds are dispersed to, both suitable and marginal habitats.
Bin Wen +5 more
wiley +1 more source
Dianci bileiqi, 2023 酥朽断裂是如今高压输电线路中复合绝缘子的新型机械故障，现有的研究均集中于酥朽断裂绝缘子芯棒的老化过程和理化特性，但很少有研究在实验室试验中模拟这种现象。建立了一种具有高温，酸腐蚀和高电场强度等多种老化条件的人工加速老化平台，一定程度上模拟了酥朽断裂绝缘子芯棒的典型特征。结果表明，当施加电压数小时后，使用热红外成像仪检测发现温度明显升高。与单一老化应力相比，芯棒样片在多应力条件下的温度高达61℃。此外，采用扫描电子显微镜(SEM),傅立叶变换红外(FTIR)光谱，X射线光电子能谱(XPS)和热重分析 ...
蔡汉贤 +5 more
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Uncovering Xi Jinping's Policy Agenda: Text As Data Approach
The Developing Economies, Volume 63, Issue 1, Page 9-46, March 2025.How many agendas has Xi Jinping put forth and promoted since taking office in 2012, and what are the types of agendas? How much of political attention has each agenda received, and how has the allocation of attention changed over time? We utilize a dataset of presidential statements, speeches, and reports from 2012 to 2022 and employed automated text ...
Jaehwan Lim, Asei Ito, Hongyong Zhang
wiley +1 more source
Conservation Biology, Volume 38, Issue 6, December 2024.Abstract Free, prior, and informed consent (FPIC) is now a globally established norm and is a condition of equitable engagement with Indigenous peoples and local communities in biodiversity conservation. However, implementation is frequently questioned in terms of its efficacy in top‐down‐driven governance contexts.
Peter Bille Larsen +1 more
wiley +1 more source
Dianci bileiqi, 2014 为了分析直流氧化锌压敏电阻的老化性能及其试验方法,根据氧化锌压敏电阻的老化机理,结合双肖特基势垒和电子迁移理论,提出了直流氧化锌压敏电阻的老化劣化与其直流电压及冲击电流极性有关。通过针对同一型号多个压敏电阻进行的大量实验证明:长期承受直流工作电压及同极性的冲击电流冲击会使压敏电阻老化加速,反之其老化程度明显降低。
刘琦, 赵军, 张利华, 冯凯
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Dianci bileiqi, 2023 室温硫化(RTV)硅橡胶老化程度的现场无损定量表征在实践中具有很重要的意义。笔者提出了采用指示剂的发光强度作为指征指标表征RTV硅橡胶老化程度的定量表征方法。通过以SrAl2O4∶Eu2+,Dy3+作为指示剂，采用人工加速老化的方式处理RTV硅橡胶，并测量了样品的余辉亮度、机械性能和表面形貌等。结果表明，■与人工加速老化处理时间呈线性关系。基于此，根据实际测量的■可以得到RTV硅橡胶老化程度。■的分布较窄表明本方法的精度较高；提供了本方法中对余辉强度测量的时间限制。证明了本方法的可行性。
夏兵 +8 more
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