Results 1 to 10 of about 6,968 (116)
Gaoya dianqi, 2021 为了研究热老化对发电机定子线棒用环氧—云母绝缘频域介电特性的影响,在170℃环境下对线棒样段进行加速热老化试验,老化时间分别为0、7、14、21 d。通过频域介电谱法测试了不同老化时间试样的频域介电谱,分析了老化时间对介质损耗和相对介电常数的影响;采用扫描电子显微镜和傅里叶红外光谱对环氧—云母绝缘体系老化前后的微观形貌和化学结构等理化特性进行表征。结果表明:在老化前期,由于绝缘体系固化交联结构得到加强,极化强度减弱,导致介质损耗和相对介电常数与未老化试样相比有所下降;随着老化时间变长,老化程度增大 ...
杨敏 +5 more
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Gaoya dianqi, 2022 为了研究复合绝缘子硅橡胶在高频电场下的老化机理，文中搭建了高频电老化试验平台，研究了高频电场对高温硫化硅橡胶老化后微观性能的影响，结果表明：高频电老化使硅橡胶表面出现孔洞和大量裂纹，部分填料分解、流失，羟基含量先降后增，但最终仍低于未老化试样，造成界面静态介电极化率降低，削弱了界面极化强度；热解第3阶段失重量随电老化时间增加，说明PDMS分子长链断裂，极性基团数目增加，偶极子极化率和极化强度增大；此外，硅橡胶介电常数和介电损耗随老化时间增大，并在144 h出现明显的介质损耗峰。通过修正Cole ...
李光茂 +5 more
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Gaoya dianqi, 2022 电力设备中的密封材料在湿热环境中容易因老化而性能下降，由此导致的密封失效会严重影响电力设备的安全稳定运行。为研究湿热环境下密封材料的老化特性，文中选取油封和气封常用的丁腈橡胶、氟橡胶、三元乙丙橡胶进行湿热老化实验。对老化过程中密封材料的力学性能变化进行测试和分析，并利用傅里叶红外光谱、热分析仪、扫描电镜等工具对未老化和湿热老化后的密封材料进行了分析。通过试验得出结论：丁腈橡胶在湿热老化中出现填料的迁移挥发，氟橡胶、三元乙丙橡胶在湿热环境中则以吸湿增重为主；通过压缩永久变形率的变化 ...
杜钢 +4 more
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浙江大学学报. 医学版睾丸支持细胞在精子发生过程中起重要作用。精子发生的异常与睾丸支持细胞糖脂代谢紊乱密切相关。睾丸支持细胞的代谢环境为缺氧，其主要的代谢方式包括糖酵解和脂肪酸β氧化，其中糖酵解是睾丸支持细胞为生精细胞提供能量的经典途径，而脂肪酸β氧化可能是睾丸支持细胞产生腺苷三磷酸的主要途径。目前睾丸支持细胞糖脂代谢与生精细胞发育的关系、糖代谢与脂代谢之间的联系尚不明确。包括性激素在内的多种激素可以通过调控内分泌影响睾丸支持细胞糖代谢。AMPK、mTOR ...
李 舒豪, 孔 亮, 梁 景岩, 马 坦
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International Journal of Applied Linguistics, EarlyView.ABSTRACT This study examines multilingual practices in research interviews, focusing on English lexical insertions in Chinese‐language research interviews with teachers of Chinese in Australian secondary schools, and treating these code‐switches as analytically meaningful rather than incidental.
Chengwen Yuan, Tianwei Zhang, Gary Bonar
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Is Time Travel Possible? Accidental Signs as Sociolinguistic “Wormholes”
International Journal of Applied Linguistics, EarlyView.ABSTRACT Sociolinguistics primarily focuses on deliberately staged public signs, while relatively less attention has been given to ephemeral and non‐deliberate signs in urban environments. This study investigates “ accidental signs,” which are hidden historical texts suddenly exposed by unpredictable events.
Ge SONG (宋歌)
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Scientists’ warning on the global destruction of rock outcrop ecosystems
Conservation Biology, Volume 40, Issue 5, October 2026.Abstract Rock outcrops are geological formations that harbor a highly specialized biota adapted to harsh environmental conditions that differ from their surrounding landscapes. They are globally distributed, especially in old, highly weathered landscapes, and can function as habitat islands containing high levels of endemism and distinct evolutionary ...
Luiza F. A. de Paula +19 more
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Multi‐gradient warming reshapes functional traits and adaptive responses of alpine meadow plants
Functional Ecology, Volume 40, Issue 9, Page 2889-2905, September 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Plant functional traits in alpine meadows are critical indicators of ecosystem responses to climate warming, yet dynamic changes in trait networks across warming gradients and their consequences for community functions remain poorly understood.
Zhiwei Yan +6 more
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Dianci bileiqi, 2020 由于长期运行在湿热的气候环境下,近年来我国南方地区复合绝缘子异常发热、击穿断裂等故障时有发生,严重威胁了电网的安全稳定运行。为了研究复合绝缘子硅橡胶伞套的湿热老化特性,首先对高温硫化（High Temperature Vulcanization,HTV）硅橡胶进行湿热老化实验,然后利用扫描电镜、红外光谱、热重分析、介电谱和热刺激电流测试等分析手段对湿热老化和运行老化样品进行微观分析,结果表明:湿热的联合作用能够显著加速HTV硅橡胶的老化进程,随着湿热老化时间的增加,样品的表面微观形貌、化学基团、热解性能、
曾磊磊 +9 more
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Agrarianizing Urbanization: Opening the Wastelands of China's Megacities
Antipode, Volume 58, Issue 5, September 2026.ABSTRACT In two of China's largest megacities, Guangzhou and Wuhan, apparently ordinary individuals are deciding—independently, without organization, support or legal rights—to appropriate empty lands and transform them into cultivation landscapes in a practice called kāihuāng (‘wasteland opening’).
Hanxi Wang
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