Results 41 to 50 of about 17,811 (141)

126kV真空断路器电机操动机构动态仿真与试验研究

open access: yesGaoya dianqi, 2015
为了简化高压真空断路器操动机构的结构并提高其工作可靠性,笔者对不同转子结构的真空断路器电机操动机构的动态特性进行了研究。建立了126 kV真空断路器操动机构的动态仿真模型,推导了驱动电机主轴侧的等效转动惯量、动态反力以及动触头行程与驱动电机转角的关系。依据上述分析并综合考虑绕组端部效应对电机启动过程的影响,采用场—路—运动耦合法对驱动电机在断路器分、合闸操作过程中的瞬态磁场和动态机械特性参数进行了仿真计算。结合仿真结果制成了永磁驱动电机样机,进行了操动机构与断路器联机试验试验。试验结果表明 ...
林莘, 马希志, 李昊旻
doaj  

Scenarios and strategies for future‐proofing ecosystem management under climatic novelty

open access: yesConservation Biology, EarlyView.
Abstract Climate change is driving unprecedented declines in dominant, habitat‐forming foundation species across marine and terrestrial ecosystems globally. As climatic novelty becomes the norm, ecosystem reassembly will become increasingly common. Predicting and understanding these transitions, and their implications for future ecosystem functioning ...
Lauren T. Toth   +14 more
wiley   +1 more source

Overlap of nonbreeding wandering albatrosses with fisheries and implications for colony‐specific population trajectories at South Georgia

open access: yesConservation Biology, EarlyView.
Abstract Bycatch in fisheries is one of the most serious threats to pelagic seabirds, causing major population declines. Mitigation measures can reduce bycatch substantially, but many fisheries fail to apply best practices, and seabird mortality remains high.
V. Warwick‐Evans   +2 more
wiley   +1 more source

避雷器热等价性及复合外套避雷器稳态热特性初探

open access: yesDianci bileiqi, 2013
金属氧化物避雷器的热特性决定着避雷器长期带电运行的稳定性。通过对避雷器最新标准中关于热特性相关内容的解析,指出了避雷器的热特性实质包括了稳态热特性和瞬态热特性,验证比例单元与避雷器具有稳态热等价性是进行动作负载等试验的前提,给出了试验项目与评价热特性的关系,同时指出了现有标准中在试品选取方面的某些不妥。通过试验研究了复合外套避雷器的稳态热特性,给出了几点常见的热特性规律。
桑建平
doaj  

Using customs data to understand overlooked trade in non‐CITES birds between Africa and Asia

open access: yesConservation Biology, EarlyView.
Abstract The international trade in live birds poses risks to animals, people, and biodiversity. To effectively mitigate these risks, decision‐makers require information on the volume, dynamics, and direction of trade. Despite Africa once being the largest exporter of birds by region, very little data exist on recent trade in live birds not listed on ...
Alisa Davies   +4 more
wiley   +1 more source

自能式SF6断路器在不同气压下的开断过程

open access: yesGaoya dianqi, 1999
对自能式SF6断路器在不同气压下的开断过程进行了分析,得到了不同气压下操动机构的运动特性、膨胀室的状态参数、灭弧室内的气流场和电弧的动态特性.部分计算结果与试验值进行了比较,二者基本吻合.
韩书谟   +4 more
doaj  

Learning Styles, Engagement and Anxiety in AI‐Mediated Writing: A Multimodal Feedback Study

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT Artificial intelligence (AI) tools now permeate English academic writing. However, evidence on how feedback modalities align with student differences and with psychological mechanisms remains limited. Prior work often reduced learning styles to simple matches with delivery modes and treated learning engagement and writing anxiety as peripheral.
Yi Ren   +3 more
wiley   +1 more source

一种印制板罗氏线圈的结构参数和电磁参数影响研究

open access: yesGaoya dianqi, 2007
设计了一种具有单面线圈结构的印制板罗氏线圈,对其结构参数和电磁参数之间的相互影响以及它们对线圈动态特性的影响进行了研究,并归纳了影响其电磁参数和动态特性的重要因素。获得了所设计的具有单面线圈结构的印制板罗氏线圈的幅频特性和相频特性的试验曲线,利用它测量了脉冲功率源中的脉冲大电流。实验表明,所得出的有关分析和优选印制板罗氏线圈的结构参数和电磁参数的分析方法,对于快速设计具有合理结构、最优电磁参数和良好动态特性的印制板罗氏线圈,具有指导价值。
李维波   +4 more
doaj  

The Emotional Valence Paradox in Social media: A Computational Linguistic Analysis of How Sentiment, Emotion, and Content Domain Predict Social Comparisons on Rednote

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT This computational linguistic study analyzes 8743 Rednote posts to examine how sentiment, emotion, and content domain collectively shape social comparison dynamics on social media. We identify four key findings: (1) an emotional gradient, where upward comparison content exhibits the highest sentiment scores and downward comparison the lowest; (
Michelle Mingyue Gu   +7 more
wiley   +1 more source

基于双塔Transformer 的电力系统暂态稳定评估 [PDF]

open access: yes全球能源互联网
基于数据驱动的方法在电力系统暂态稳定评估的效率和精度提升上已经取得了一些研究成果。然而电力系统暂态过程中涉及多维度时序特征的变化,常规算法对特征的提取能力不足且缺乏可解释性,难以反映系统暂态过程中的动态行为。因此,构建了一个具有双塔结构的Transformer模型,以Transformer编码器作为特征提取器,考虑同一时刻不同维度的特征以及每一维度特征在不同时间步对系统暂态稳定的影响,并将其分别作为双塔结构Transformer模型的输入,训练和学习各特征通道和时间步对系统暂态稳定性的影响。通过融合机制,
赵晨浩   +4 more
doaj   +1 more source

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