Results 51 to 60 of about 4,341 (167)
Gaoya dianqi, 2023 高压电缆长期运行过程中温度引起的绝缘材料热老化是影响其整体绝缘性能的重要因素。通过对高压电缆主绝缘层切片取样，研究分析了不同老化程度试样的微观形貌、官能团、结晶度、交联度等理化性能变化规律，测试分析了不同老化程度试样的电阻特性、介电性能和击穿特性，仿真模拟了不同温度下交联聚乙烯分子链的运动情况，进一步讨论了热老化对其微观结构的破坏演变机理。研究结果表明，老化2 160 h后试样的晶区结构破坏较为严重，随着老化时间的延长，相邻晶区的间距增大，晶区排列松散，无定型区面积增大；羰基指数从3.88%增大至11 ...
王兆琛 +6 more
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An integrated historical study on human–tiger interactions in China 中国人虎互动关系的综合性历史研究
Integrative Conservation, Volume 3, Issue 3, Page 183-195, September 2024.Tigers are important for maintaining a variety of life in the world as they are the top predators in the food chain. Human–wildlife conflict, including conflicts between humans and tigers, has been a global issue throughout history. This article focuses on human–tiger interactions in China, discussing various types of conflicts and measures for ...
Zhihong Cao +4 more
wiley +1 more source
Multichannel Online Lifetime Accelerating and Testing System for Light-Emitting Diodes [PDF]
, 2017 LED寿命长达数万小时，具有高效、节能、环保、高可靠性的优点，是当前国家正在提倡和推广的照明光源。然而，LED长寿命的优点却成为寿命评估的短板，需要耗费大量时间。加速寿命可大大缩短实验时间，同时也是探索LED失效机理，进一步提升LED性能的有效手段。传统的LED加速寿命方法往往采用离线测试方法，将样品连同夹具置于高温箱中，通过高温箱控制样品的整体环境温度，但是在老化过程期间需要中断老化，将样品冷却取出对其各个参数进行测试。为了更加便捷地连续性测试，一些科研机构也提出了在线测试方法 ...
肖菁菁
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Reforming the Dutch pension system to ensure sustainability
International Social Security Review, Volume 77, Issue 3, Page 99-122, July/September 2024.Abstract The Netherlands is on the brink of reforming its system of occupational pensions as part of a more general reform of its three‐pillar pension system. This reform features important changes to first pillar pension benefits. The focus of this article is however on the coming reform of occupational pensions, the second pillar of the system, which
Ed Westerhout +2 more
wiley +1 more source
Dianci bileiqi, 2006 对大量运行的高温硫化硅橡胶（HTV）绝缘子进行了憎水性试验、低温模拟试验、灰密对憎水性的影响以及耐漏电起痕及电蚀损试验,认为高温硫化硅橡胶因老化而引起的憎水性下降、机械强度下降及积污性能下降影响其长期工作的可靠性,所以评价复合硅橡胶的憎水性能除憎水性分级HC值外,还应重点突出评价憎水性的减弱（丧失）特性、憎水性的恢复特性及憎水性的迁移特性。低温模拟试验表明,低温下憎水性有一定程度的下降,应针对性地开发应用于低温地区的高温硫化硅橡胶,并制订新的判定准则。最后对硅橡胶材料老化试验方法进行了讨论 ...
张予, 吴光亚, 张锐
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Gaoya dianqi, 2018 为研究油浸式变压器中油浸普通牛皮绝缘纸和油浸热稳定绝缘纸的时域介电特性,文中在实验室开展了不同温度下的油纸样品加速热老化试验。通过极化去极化电流法（PDC）获得PDC曲线,根据曲线分析不同类型油纸绝缘在老化过程中的极化特性差异,从PDC曲线中提取电导率并拟合得曲线,探寻能够表征不同类型油纸绝缘老化程度的特征量。结果表明:普通牛皮绝缘纸试样的老化速度快于热稳定绝缘纸,且在老化后期,后者聚合度下降速率变缓更明显;PDC曲线对绝缘材料的变化十分敏感,对于老化时间相同的两种材料 ...
高波 +4 more
doaj
The Analysis of the Characteristics of High Power LED under High-stresses [PDF]
, 2012 半导体照明是目前国家重点扶持的新兴技术，大功率LED是半导体照明的关键器件。目前LED实际寿命和理论寿命(10万小时)仍有不小差距，这是由于器件材料、结构、工艺、封装等环节的缺陷，因此在研究LED新的工艺以及结构的同时，需要对其老化机理进行深入分析。本文主要针对功率型LED在脉冲和大应力条件下的光、电、热特性展开研究，以探索影响其可靠性的因素及老化机理。具体包括以下内容： 1.简单介绍了LED发展历史和现状，并且针对器件可靠性进行了综述分析，结合当前的研究，对LED的失效机理分别作了总结。 2.从光学 ...
薛浩
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Effect of Sea Buckthorn Pomace Addition on the Quality and Digestive Attributes of Noodles [PDF]
This study provided a theoretical framework for the development of functional noodles based on effective utilization of resources and developmental trends in food nutrition and health.
Dandan FANG +3 more
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The Modern Language Journal, Volume 108, Issue 1, Page 222-242, Spring 2024.Abstract In response to the issue of Chinese language teacher attrition in Myanmar, this study aimed to examine the professional commitment of these teachers, with a focus on how their commitment is constructed and shaped within the local context. The study adopted a theoretical lens of positive psychology and utilized a hermeneutic phenomenological ...
Yue Peng, Kaiyang Lou, Tao Xiong
wiley +1 more source