Results 21 to 30 of about 5,560 (166)
The Empty State: Governing the Voids in a Projected Conflict‐Torn Yemen
Politics &Policy, Volume 53, Issue 5, October 2025.ABSTRACT This study introduces the concept of the “Empty State” to explain a form of state dysfunction in Yemen, where state institutions exist but are stripped of their governance authority. While frameworks on fragile or failed states emphasize the weakness or collapse of state capacity, the Empty State highlights the persistence of symbolic ...
Moosa Elayah
wiley +1 more source
Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 5, Page 624-632, May 2025.ABSTRACT Objectives Placental insufficiency contributes to many obstetric pathologies, but there is no bedside clinical tool to evaluate placental perfusion. We have developed a method to acquire multiple three‐dimensional (3D) power Doppler (PD) ultrasound (US) volumes of placental vasculature, with infrared camera tracking of the precise spatial ...
A. Xue +5 more
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Conservation Biology, Volume 39, Issue 2, April 2025.Abstract Emerging infectious diseases are increasingly recognized as a significant threat to global biodiversity conservation. Elucidating the relationship between pathogens and the host microbiome could lead to novel approaches for mitigating disease impacts.
Alexander S. Romer +25 more
wiley +1 more source
Study of Resistivity of Evaporated Nickel-Chromium Thin Film Deposited by Oblique Incidence [PDF]
, 1970 This paper reports the resistivity of evaporated Chromium,Nickel-Chromium (80%Ni-20%Cr) and Nickel films deposited on glass by the oblique incidence. The specific resistivity of the Chromium film showed very large values owing to oxidation.
四谷 平治, 畠山 豊正
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Gaoya dianqi, 2008 为了找到一种操作简便且准确度高的方法来进行真空度评估,笔者提出了一种不需外施磁场、利用测量X射线量变化来判断真空灭弧室内部真空度的方法。对于真空灭弧室在指定开距下施加工频电压时,场致发射电子会以很高的速度从阴极表面逸出,在触头间电场的作用下加速轰击阳极,基于轫致辐射的原理会从阳极表面释放出X射线。这时,真空度的差异会使产生的X射线释放强度以及变化情况有所不同,因此,利用测量释放的X射线量的变化可判断真空灭弧室内部的真空度。笔者通过理论分析,得出了X射线量与真空度的关系,并进行了试验验证。
李炜 +5 more
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Towards a global understanding of tree mortality
New Phytologist, Volume 245, Issue 6, Page 2377-2392, March 2025.Summary Rates of tree mortality are increasing globally, with implications for forests and climate. Yet, how and why these trends vary globally remain unknown. Developing a comprehensive assessment of global tree mortality will require systematically integrating data from ground‐based long‐term forest monitoring with large‐scale remote sensing.
International Tree Mortality Network +114 more
wiley +1 more source
Gaoya dianqi, 2007 笔者在实验室对真空开关灭弧室真空度停电测量新方法"发射电流衰减法"和在线检测新方法"屏蔽罩磁控放电法"进行了实验研究。结果表明:"!在将真空开关的真空间隙调整为0.8 mm的小间隙以后,不需要施加磁场,使用发射电流衰减法可以停电测量灭弧室内的真空度;#"研制出具有良好内外绝缘的励磁线圈以后,使用磁控放电法能以6×10-2 Pa的灵敏度在线检测真空开关真空度。
顾保华 +5 more
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Gaoya dianqi, 2010 真空开关是在低压及中压领域应用广泛的电力开断器件,真空度是决定真空开关开断性能的主要因素之一。为实现真空开关真空度的在线测量,笔者介绍了基于磁控放电法的真空开关真空度测试仪的研制方法,分析了磁控放电法的基本原理,利用开关电源技术设计并研制了高压电场电源和励磁系统,实现了离子电流的测量及控制电路设计等,同时为了实现户外的便携式操作,完成了锂离子电池电源的研制。利用研制的测量仪对一款12kV的真空开关进行测试,获得了离子电流-真空度曲线。
王东珏 +6 more
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Gaoya dianqi, 2023 采用有限元法对12 kV真空灭弧室的电场特性进行了单因素分析，结合SPSS软件对其进行了正交回归分析，选取触头圆倒角、触头开距、主屏蔽罩半径、主屏蔽罩卷边半径、主屏蔽罩卷边角度和主屏蔽罩坡度这6个主要参数进行综合优化研究。得到了电场特性和设计参数之间的回归方程，找出了影响电场特性的显著因素。研究结果表明：触头圆倒角和触头开距对真空灭弧室典型点的电场强度有高度显著影响，主屏蔽罩半径对真空灭弧室典型点的电场强度有显著影响；触头圆倒角和触头开距对真空灭弧室触头处最大电场强度有显著影响 ...
王文成 +4 more
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