Results 21 to 30 of about 6,526 (127)
Gaoya dianqi, 2012 准确预测变压器油中溶解故障特征气体的体积分数对发现变压器早期潜伏性故障,实现电力系统安全经济运行具有重要意义。将灰色多变量预测方法和马尔可夫链理论有机结合,提出了一种适合变压器故障特征气体体积分数预测的灰色马尔可夫组合预测模型。利用优化的背景值构造公式建立灰色多变量模型对变压器故障特征气体时间序列的宏观发展规律进行动态预测,在此基础上,建立故障特征气体时间序列的状态转移概率矩阵,以归一化的各阶自相关系数作为权重值,通过加权马尔可夫链模型修正灰色多变量模型预测值,实现变压器故障特征气体体积分数的预测 ...
毛自娟
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Gaoya dianqi, 2021 SF6因其性能优异而广泛应用于电力工业,当电气设备出现放电故障或过热故障时,SF6气体将不可避免地发生分解。研究SF6分解机理,掌握SF6分解特性,以期提高设备的运维水平。文中从SF6分子解离、特征产物生成路径等方面,总结了SF6气体放电分解机理的相关研究进展,鉴于定性检测方法的局限性,指出结合DFT、ReaxFF等研究方法可厘清SF6的复杂分解过程;重点介绍了开展气体分解特性研究的基本测量与分析方法,包括:气相色谱质谱法、红外吸收光谱法及气敏传感器法等,其中气敏传感器因具备小型化、强响应等优势 ...
石磊 +9 more
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Ultrasound in Obstetrics &Gynecology, Volume 66, Issue 6, Page 706-715, December 2025.ABSTRACT Objective To evaluate the use of twin vs singleton growth charts for detecting small‐for‐gestational‐age (SGA) twins at risk of adverse neonatal outcomes. Methods MEDLINE, EMBASE, CINAHL, Cochrane and Scopus databases were searched electronically from inception to May 2024.
S. Sorrenti +9 more
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Functional Ecology, Volume 39, Issue 12, Page 3504-3516, December 2025.Read the free Plain Language Summary for this article on the Journal blog. Abstract Nitrogen (N) deposition strongly affects litter decomposition and nutrient release, thereby reshaping carbon cycling in terrestrial ecosystems. Although most studies have focused on above‐ground litter, the effects of N addition on fine root decomposition and their ...
Yuneng Wang +5 more
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Gaoya dianqi, 2010 笔者以SF6气体分解机理为基础,分析了不同故障情况下SF6气体中的特征杂质气体。得出:电弧和热分解的主要产物是SOF2;在热分解条件下,如能够检测出SO2,则可能存在金属性过热故障;CF4、CO和CO2的体积分数异常增加,故障则可能涉及到固体绝缘材料;设备存在内部潜伏性故障的特征气体是HF。通过检测SF6气体中杂质气体的体积分数可对GIS的故障进行分析判断。
姚强, 王勇, 刘永
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Rare Metals, Volume 44, Issue 11, Page 8161-8197, November 2025.Graphical abstract AbstractThe studies on the synthesis of two‐dimensional (2D) Janus materials have made significant progress over the years. They offer new opportunities to increase the potential usage of Janus transition metal dichalcogenide (TMDC) materials in different application areas due to their unique structural, electrical, optical and ...
Ayça Coşkun +9 more
wiley +1 more source
Functional Ecology, Volume 39, Issue 11, Page 3255-3268, November 2025.Read the free Plain Language Summary for this article on the Journal blog. Abstract The biotic resistance hypothesis (BRH) of Elton posits that diverse communities are more resistant to biological invasions. While the effects of climatic stresses and human disturbances on community invasibility have been extensively studied individually, their combined
Kai Shi, Misbah Naz, Chi Zhang, Hua Shao
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Gaoya dianqi, 2013 笔者使用自行设计126 kV交流工频电源和GIS局部放电实体实验平台以及气体分析检测系统,模拟对地放电故障状态,对局部放电引起的SF6分解物特征组份气体进行定性定量分析,用脉冲电流法对局部放电强度进行监视,得到局部放电引起SF6气体分解物特征组份及变化规律。研究表明:局部放电致使SF6气体发生分解,特征组分为SOF2、SO2、S2OF10,SOF2、SO2与局放持续时间、局放强度呈现正相关性,吸附剂对于SF6分解物检测有影响。
鲁钢 +4 more
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Global Change Biology, Volume 31, Issue 11, November 2025.This study assessed the potential impacts of climate and land‐use change on soil fungal diversity across four North American biomes. We found that climate change typically caused both diversity losses and gains, particularly in coniferous forests and among arbuscular mycorrhizal fungi, whereas land‐use change mainly reduced diversity, especially in ...
Wenqi Luo +5 more
wiley +1 more source
Gaoya dianqi, 2016 悬浮放电是GIS的典型缺陷之一。通过对GIS设备局部放电的检测和分析,可实现设备状态评估和故障诊断。文中利用脉冲电流法和分解物检测法,研究了间断恒压法下GIS悬浮缺陷模型局部放电发展过程及其分解产物的特征,并在局部放电已产生分解物的前提下,探究了各分解气体的扩散特征。实验结果表明:局部放电放电特征量不因外施电压间断而发生改变;局部放电发展中SF6气体水分体积分数呈增长趋势,仅用SF6气体微水含量偏高来推测GIS设备受潮存在一定局限;若分解物检测试验中只检测到SO2气体 ...
王琼, 车传强, 王慧君, 李波
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