Results 21 to 30 of about 14,863 (167)

Resource Substitution: Local Governments' Issue Attention and Policy Reinvention

open access: yesPolicy Studies Journal, EarlyView.
ABSTRACT Research on policy reinvention, where a government modifies rather than replicates policy innovations introduced by other governments, has progressed significantly, but how it is influenced by the government's issue attention has not been thoroughly examined.
Yingxin Zhang, Yixue Yao, Kaifeng Yang
wiley   +1 more source

特高压混合式MMC低全桥配比下单阀组投退过程中的均压控制 [PDF]

open access: yes全球能源互联网, 2018
低全桥子模块配比的混合式模块化多电平换流器(modular multi-level converter,MMC)应用于高低阀组拓扑结构的特高压柔性直流系统时,在单阀组在线投入/退出过程中存在半桥子模块持续充/放电引起的子模块电压不均衡问题,严重影响系统安全。通过详细的理论分析,指出阀组投入/退出过程中桥臂电流不存在过零点是导致半桥子模块持续充放电问题的本质原因。为此提出了基于环流注入的单阀组投/退过程中的均压控制,在阀组投退期间控制MMC产生一定的相间环流,人为创造正负交替的桥臂电流,为半桥子模块充 ...
杨美娟   +5 more
doaj   +1 more source

Focusing Events, Agenda Setting, and Narrative Numbing

open access: yesReview of Policy Research, Volume 43, Issue 3, May 2026.
ABSTRACT Focusing events are important in understanding policy change, as demonstrated in Birkland's work on agenda setting, the multiple streams framework, and the narrative policy framework. These frameworks emphasize the role of focusing events in drawing public attention to broader issues.
Megan K. Warnement Wrobel   +1 more
wiley   +1 more source

A Review on Cracking in Laser Additive Manufacturing of Nickel‐Based Superalloys: Types, Formation Mechanisms, and Suppression Strategies

open access: yesRare Metals, Volume 45, Issue 4, April 2026.
ABSTRACT Nickel‐based superalloys (Ni‐based superalloys) have attracted extensive attention in laser additive manufacturing (LAM) due to their capability to directly fabricate complex and high‐performance structural components. However, the rapid melting and solidification inherent to LAM result in intense thermal cycling, which induces high residual ...
Tianxiang Lin   +9 more
wiley   +1 more source

Electrospinning‐Driven IGZO Nanofiber Phototransistors Bridging Adaptive Processing and Recognition Learning

open access: yesRare Metals, Volume 45, Issue 4, April 2026.
ABSTRACT The development of neuromorphic electronics with visual perception and adaptive capability is highly desirable for advancing artificial vision systems. Herein, we have demonstrated a dual‐plasticity adaptive phototransistor based on IGZO nanofibers that exhibits the perception and dynamic adaptation behavior of rod and cone cells to varying ...
Shanshan Jiang   +5 more
wiley   +1 more source

采用钢柱接地的钢结构变电站防雷接地特性研究

open access: yesDianci bileiqi, 2022
笔者针对钢结构变电站直击雷防护,对雷击过程中变电站接地特性进行研究,相较于通过避雷带引下线接地的现行方案,在采用钢柱直接接地情况下,地表电位升最大值下降幅度达到26.5%。钢结构变电站的导体网络对于具有大量高频分量的雷电流具有明显的电感效应,地表电位升峰值时刻超前于雷电流约5μs。雷电流散流集中于注流点附近的4~5条引下线或者连接线,总散流占比超过90%,相比现行方案,通过钢柱接地的方案散流更加集中于注流点附近的4条连接线,距离注流点最近的连接线分流占比达到了55.19 ...
李凡   +5 more
doaj  

Automating the analysis of public saliency and attitudes toward biodiversity from digital media

open access: yesConservation Biology, Volume 40, Issue 2, April 2026.
Abstract Measuring public attitudes toward wildlife provides crucial insights into human relationships with nature and helps monitor progress toward Global Biodiversity Framework targets. Yet, conducting such assessments at a global scale presents challenges.
Noah Giebink   +8 more
wiley   +1 more source

抑郁症状与SPECT局部脑血流灌注的相关探讨

open access: yesZhongshan Daxue xuebao. Yixue kexue ban, 2007
[目的]采用单光子发射计算机断层扫描(SPECT)技术测定抑郁症患者的局部脑血流(rCBF),与正常对照比较脑血流灌注变化,并观察抑郁症症状与患者脑血流灌注的关系。[方法]以18例未经抗抑郁治疗的抑郁症患者为研究对象,19名正常人作为对照组,分别行SPECT检查。[结果]未经治疗的抑郁患者SPECT脑血流低灌注发生率为72.2%;重症抑郁患者100%存在脑血流低灌注;抑郁组患者双侧额叶、颞叶的rCBF较对照组显著下降(P〈0.01~0.05),左顶叶、右基底节rCBF也明显降低(P〈0.05 ...
贾艳滨, 黄立安, 徐伊, 徐浩
doaj  

±800 kV直流输电线路正极性侧带电作业电位转移放电特性研究

open access: yesDianci bileiqi, 2020
为明确±800 kV直流输电线路带电作业电位转移放电特性,考虑强电场作用下粒子产生、运动和消散过程,构建了基于流体力学理论的电位转移流注放电模型,计算并分析了放电过程中的电场强度、流注发展速度和电流密度随时间的变化规律,以及不同转移距离下的放电电流。结果表明:在电位转移放电过程中,随着放电时间的增加,流注头部电场强度减小、流注发展速度加快、电流密度增大;电位转移棒与导线间的放电电流随着电位转移距离的减小而增大;确定了±800 kV输电线路在正极性导线侧带电作业时最佳电位转移距离为0. 45 m左右。
周晨梦   +7 more
doaj  

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