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绝缘子直流污闪时Hampton判据的适用性 被引量:4
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作者 徐志钮 律方成 李和明 《高电压技术》 EI CAS CSCD 北大核心 2010年第11期2639-2644,共6页
直流污闪模型中可用Hampton判据来获得闪络的临界弧长,但该方法在某些情况下存在误差。因此分析了直流情况下基于Obenaus模型的污闪电压预测方法的原理,指出并证明了当不考虑弧根半径的影响时临界弧长仅与泄漏距离L和电弧参数n有关,而... 直流污闪模型中可用Hampton判据来获得闪络的临界弧长,但该方法在某些情况下存在误差。因此分析了直流情况下基于Obenaus模型的污闪电压预测方法的原理,指出并证明了当不考虑弧根半径的影响时临界弧长仅与泄漏距离L和电弧参数n有关,而与其它因素无关,Hampton判据完全正确,并通过计算进行了验证。考虑弧根半径的影响时根据Hampton判据预测的直流污闪电压存在误差,其值略低于模型实际预测的污闪电压。分析了电弧参数A、n、等值盐密、泄漏距离、平均直径等因素对误差的影响,结果表明:随着A、n、等值盐密、泄漏距离的增加,相对误差减少;随着平均直径的增加,相对误差增大。当不考虑弧根半径的影响时应将L/(1+n)作为临界弧长以减少计算量,当考虑弧根半径的影响时应在0-L范围内搜索临界弧长以获得模型准确的污闪电压。 展开更多
关键词 绝缘子 污闪 直流 Hampton判据 Obenaus模型 误差
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绝缘子交流污闪时Hampton判据适用性的分析 被引量:2
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作者 徐志钮 律方成 李和明 《高电压技术》 EI CAS CSCD 北大核心 2010年第12期2889-2895,共7页
为了提高Obenaus模型预测污闪电压的准确性,建立了Obenaus交流污闪模型,模型中用Hampton判据或全范围搜索法获得绝缘子的临界弧长。研究发现交流时根据Hampton判据预测的污闪电压与模型的实际污闪电压存在偏差,与人工污秽试验结果的比... 为了提高Obenaus模型预测污闪电压的准确性,建立了Obenaus交流污闪模型,模型中用Hampton判据或全范围搜索法获得绝缘子的临界弧长。研究发现交流时根据Hampton判据预测的污闪电压与模型的实际污闪电压存在偏差,与人工污秽试验结果的比较也表明较之全范围搜索法Hampton判据预测的污闪电压有更大的误差。在此基础上分析了电弧参数A、n、附盐密度、泄漏距离L、平均直径对误差的影响。研究结果表明:计算剩余污层电阻时无论是否考虑弧根半径的影响,交流下Hampton判据导致的误差远大于直流情况;交流时Hampton判据预测的污闪电压偏低,一般要偏小30%左右,随电弧参数A、n、附盐密度、泄漏距离、平均直径的增加相对误差减少;将L/(n+1)作为临界弧长的污闪电压计算方法在电弧参数n较小时误差稍大,否则误差均保持较小值。无论是否考虑弧根半径的影响,欲在不同情况下都能获得模型准确的污闪电压值,应在0~L范围内搜索临界弧长。 展开更多
关键词 绝缘子 污闪电压 交流 Hampton判据 Obenaus模型 误差
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Augmentation of literature review of COVID-19 radiology
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作者 Suleman Adam Merchant Prakash Nadkarni Mohd Javed Saifullah Shaikh 《World Journal of Radiology》 2022年第9期342-351,共10页
We suggest an augmentation of the excellent comprehensive review article titled“Comprehensive literature review on the radiographic findings,imaging modalities,and the role of radiology in the coronavirus disease 201... We suggest an augmentation of the excellent comprehensive review article titled“Comprehensive literature review on the radiographic findings,imaging modalities,and the role of radiology in the coronavirus disease 2019(COVID-19)pandemic”under the following categories:(1)“Inclusion of additional radiological features,related to pulmonary infarcts and to COVID-19 pneumonia”;(2)“Amplified discussion of cardiovascular COVID-19 manifestations and the role of cardiac magnetic resonance imaging in monitoring and prognosis”;(3)“Imaging findings related to fluorodeoxyglucose positron emission tomography,optical,thermal and other imaging modalities/devices,including‘intelligent edge’and other remote monitoring devices”;(4)“Artificial intelligence in COVID-19 imaging”;(5)“Additional annotations to the radiological images in the manuscript to illustrate the additional signs discussed”;and(6)“A minor correction to a passage on pulmonary destruction”. 展开更多
关键词 COVID-19 radiological findings Chest radiographs hamptons hump Westermark sign Computed tomography Cardiac magnetic resonance imaging COVID-19-associated coagulopathy COVID-19 imaging Artificial intelligence in COVID-19
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Mechanisms for Cross-Scaling, Flexibility and Social Learning in Building Resilience to Sea Level Rise: Case Study of Hampton Roads, Virginia 被引量:1
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作者 Carol Considine Michelle Covi Juita-Elena (Wie) Yusuf 《American Journal of Climate Change》 2017年第2期385-402,共18页
This case study examines how the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project, a whole-of-government and whole-of-community approach to planning for and adapting to... This case study examines how the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project, a whole-of-government and whole-of-community approach to planning for and adapting to sea level rise, addressed coastal resilience in a southeastern Virginia watershed that spans multiple jurisdictions. Meeting the challenge of sea level rise requires that actors across multiple sectors—citizens, community organizations, industry and government—understand the risks and work together to make critical decisions regarding adaptation strategies and actions. The case study area includes Little Creek Amphibious Base, which is bordered by the cities of Norfolk and Virginia Beach. Adaptation responses to sea level rise by the military base and the local governments will impact each other and the residents of the area, but no cooperative agreements are in place for a joint or collaborative response. This case study examines public and private infrastructure at risk, the infrastructure interdependencies, and mechanisms for providing collaborative solutions. Engagement of area residents and other stakeholders is also integral to the process of adaptation, which includes educating about sea level rise risk and provides a mechanism for social learning that enables stakeholders to participate in critical adaptation decisions. The case study demonstrates a method to improve resiliency in the case study area and inform a regional, multi-sectoral response to sea level rise adaptation strategies. 展开更多
关键词 Sea Level RISE Multi-Sectoral Adaptation Hampton ROADS Critical Infrastructure Social Learning Socio-Ecological RESILIENCE Cross-Scaling
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“He Did Not Call Himself an Artist”:Revisiting Ronald Johnson’s Outsider Aesthetic
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作者 Norman Finkelstein 《Journal of Foreign Languages and Cultures》 2019年第1期30-38,共9页
Ronald Johnson’s relationship to outsider art has long been recognized as crucial to our understanding of his poetry.In interviews and other statements,the poet often affirms his connections with the self-taught make... Ronald Johnson’s relationship to outsider art has long been recognized as crucial to our understanding of his poetry.In interviews and other statements,the poet often affirms his connections with the self-taught makers of fantastic,visionary sculptural environments.The works of such figures as Simon Rodia,le Facteur Cheval,Raymond Isidore,and James Hampton serve as formal and thematic models for the enormous verbal construction that is ARK.In this essay,I argue that although Johnson is by no means an outsider artist-he is a formally schooled,sophisticated late modernist poet-his fascination with these figures betrays a powerful longing to achieve a state of original innocence which he perceives in their work,but which he knows that he cannot claim.The gates of Eden,as it were,are closed to the poet.By examining a number of passages in ARK,I determine that the great poem which Johnson composes serves as the gorgeous compensation for the loss of belief that artists such as Rodia and Hampton still hold.Treating language as bricolage,in much the same way some of these artists gather the basic material for their work through oddments and cast offs,Johnson transforms his poem into“scrapture”-a text made of scraps that form a scripture leading poet and reader to a state of rapture. 展开更多
关键词 Ronald Johnson ARK outsider art James Hampton BRICOLAGE
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