Results 1 to 10 of about 764,556 (168)
Gaoya dianqi, 2021 多断口真空断路器的各个串联断口存在非同期现象,为此需要探明非同期的影响,进而得到在不降低其开断能力的情况下的有限异步分断方法。文中以永磁操动的模块化真空断路器为研究对象,分析了影响永磁操动精度的因素,理论分析了非同期对多断口真空断路器开断能力的影响,综合杂散电容和弧后不平衡电荷的影响,提出了三断口真空断路器的有限异步开断方法。搭建了模块化串联多断口真空断路器试验平台,试验研究了有限异步开断方法对开断成功率的影响。试验结果表明:高压侧提前动作1.7 ms,可将开断成功率提高16 ...
曾祥浩 +4 more
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Zhongguo shiyan zhenduanxue, 2021 口腔疾病常见于老年患者,据全国第4次口腔健康流行病学调查结果证实[1],我国老年口腔疾病患者健康情况从整体上较10年前有所改善,但与世界卫生组织对老年健康的要求相比仍具有较大的改善空间。同时,老年患者多伴随多种合并症,属于疾病高危人群。老年口腔疾病患者多伴有多种并发症。在口腔疾病进展、临床体征与康复方面具有一定的特殊性[2]。随着精准、无创理念的不断发展,越来越多的具有无创性质的诊断技术被用于口腔疾病的诊断。唾液相关检查技术作为取材方便、安全性高的无创筛查技术被用于口腔疾病患者的临床诊治及随访阶段[3]。
王晓龙
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Gaoya dianqi, 2021 多端口混合直流断路器是一种可同时保护多条线路,且投资成本相对较低的新型断路器拓扑,在多端直流配电系统中具有广阔应用前景。文中针对晶闸管换流式多端口混合直流断路器进行研究,介绍了其用于N条线路保护的拓扑图,详细分析在正常运行、故障运行以及重合闸运行时断路器的保护动作过程及电路换流状态。最后,在PSCAD/EMTDC软件内搭建了三端MMC直流输电系统仿真模型,通过分析断路器在故障点的故障切除特性,验证了多端口混合直流断路器拓扑结构的可行性和有效性。
杨景刚 +5 more
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2021年玛多MW7.4地震强震加载及其对周围地区应力扰动的影响
Dizhen xuebao, 2023 2021年5月22日在青海玛多发生MW7.4地震，为了探究玛多地震的不同滑动模型对周围地区及断层应力的加卸载作用，本文首先以GNSS数据为约束，结合中国地震局地质研究所公布的玛多地震同震滑动模型（模型A）断层面几何结构反演获得同震滑动模型（模型C），再分别利用模型A、模型B（USGS）、模型C计算玛多地震对周围地区及断层的应力加卸载作用。结果显示：① 模型C矩震级为MW7.46，最大滑动量为3.39 m，主体破裂位于0—10 km深度范围，整体破裂东侧大于西侧，滑动分布相对于模型A也更加均匀平滑 ...
Shuaipeng Wang, Keke Xu, Xiaoyi Wang
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Ultrasound in Obstetrics &Gynecology, Volume 67, Issue 4, Page 461-469, April 2026.ABSTRACT Objective The aim of this study was to evaluate the perinatal outcomes of monochorionic diamniotic (MCDA) twin pregnancies complicated by early twin‐to‐twin transfusion syndrome (TTTS) treated with fetoscopic laser surgery (FLS), and to compare rates of fetal survival across Quintero stages.
F. G. Sileo +35 more
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How much biotic nativeness matters across human demographic groups
Conservation Biology, Volume 40, Issue 2, April 2026.Abstract Many central concepts of conservation biology—such as nativeness—are structured by ecological and social factors. However, the social consequences of using these concepts to make conservation decisions remain inadequately understood. Some researchers argue that nativeness, rather than acting as an objective proxy for important ecological ...
Harold N. Eyster, Rachelle K. Gould
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Gaoya dianqi, 2022 直流断路器是城市轨道牵引供电系统的关键设备。目前轨道直流牵引供电系统配置的断路器以机械式空气断路器为主，其开断过程存在触头和熄弧栅片烧蚀、故障电流开断速度慢等问题，而混合式直流断路器造价过于昂贵。针对以上问题，分析了单/多端口直流断路器的关断原理及其在轨道牵引中的故障隔离性能、具体配置方法以及各自优缺点，通过仿真分析，验证了混合式直流断路器在轨道牵引系统故障中的阻断能力，并着重研究了多端口直流断路器在目前城铁牵引直流系统中应用改造的可行性。
陈宪祖
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Impacts of Human Development on Wildlife Use of Corridors in Botswana 人类开发对博茨瓦纳野生动物廊道利用的影响
Integrative Conservation, Volume 5, Issue 1, Page 164-171, March 2026.This study examined the effect of landscape‐scale human impact on wildlife in Botswana. We examined how species use wildlife corridors in two different human‐dominated landscapes. We identified differences in temporal overlap between wildlife and humans across both landscapes, which is fundamental to consider in both current and future conservation ...
Tempe S. F. Adams +3 more
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Governance of Climate‐Induced Relocation in the US: An Exploration of Institutional Complexity
Review of Policy Research, Volume 43, Issue 2, March 2026.ABSTRACT Climate change has and will continue to have a profound effect on both individuals and the communities in which they reside. A pressing question is how communities forced to confront climate‐induced catastrophe—including both rapid and slow‐onset hazards—undertake the decision of how and when to relocate, particularly given the multiple scales
Christopher S. Galik, Brad A. Johnson
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Rare Metals, Volume 45, Issue 1, January 2026.ABSTRACT TA18 alloy is an ideal material for piping systems in the aerospace field, the low notch sensitivity and high damage tolerance enhance its engineering application value. However, the complex failure mechanism influenced by strain gradient necessitates further improvement of the service stability for TA18 alloy in practical engineering ...
Xin Du +6 more
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