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低阻抗强流箍缩电子束二极管的3阶段电子束流模型 被引量:4
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作者 蒯斌 邱爱慈 +2 位作者 王亮平 丛培天 梁天学 《强激光与粒子束》 EI CAS CSCD 北大核心 2004年第12期1603-1606,共4页
 在顺位流模型与"4阶段"粒子流动模型的基础上,提出了一种用于分析100ns/MA级电子束流的低阻抗强箍缩二极管物理过程的理论模式。在这种理论分析模式中,将电子和离子的流动情况随时间的演变过程分成非箍缩电子流、弱箍缩电...  在顺位流模型与"4阶段"粒子流动模型的基础上,提出了一种用于分析100ns/MA级电子束流的低阻抗强箍缩二极管物理过程的理论模式。在这种理论分析模式中,将电子和离子的流动情况随时间的演变过程分成非箍缩电子流、弱箍缩电子流、强箍缩电子流3个不同的阶段,分别结合聚焦流和顺位流模型对各个阶段特性进行估算。利用KARATPIC数值模拟软件并结合"强光一号"加速器的工作状态,对该类型二极管中电子束的流动过程作了数值模拟,并在"强光一号"加速器上开展了实验研究。数值模拟和实验结果的对比表明,所提出的新的理论分析模式是合理可行的。 展开更多
关键词 低阻抗强流箍缩电子束二极管 顺位流模型 理论分析模式 加速器
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Methodology for estimating probability of dynamical system's failure for concrete gravity dam 被引量:2
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作者 王超 张社荣 +1 位作者 孙博 王高辉 《Journal of Central South University》 SCIE EI CAS 2014年第2期775-789,共15页
Methodology for the reliability analysis of hydraulic gravity dam is the key technology in current hydropower construction.Reliability analysis for the dynamical dam safety should be divided into two phases:failure mo... Methodology for the reliability analysis of hydraulic gravity dam is the key technology in current hydropower construction.Reliability analysis for the dynamical dam safety should be divided into two phases:failure mode identification and the calculation of the failure probability.Both of them are studied based on the mathematical statistics and structure reliability theory considering two kinds of uncertainty characters(earthquake variability and material randomness).Firstly,failure mode identification method is established based on the dynamical limit state system and verified through example of Koyna Dam so that the statistical law of progressive failure process in dam body are revealed; Secondly,for the calculation of the failure probability,mathematical model and formula are established according to the characteristics of gravity dam,which include three levels,that is element failure,path failure and system failure.A case study is presented to show the practical application of theoretical method and results of these methods. 展开更多
关键词 concrete gravity dam dynamical system failure mode identification calculation of system failure probability stochastic model
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A new method determining safe thickness of karst cave roof under pile tip 被引量:21
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作者 蒋冲 刘浪 吴均平 《Journal of Central South University》 SCIE EI CAS 2014年第3期1190-1196,共7页
Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. ... Cave roofs are used to support pile foundation in many engineering projects. Accurate stability analysis method of cave roof under pile tip is important in order to ensure the safety of the pile foundation structure. Firstly the mechanical model to analysis the stability of cave roof under pile tip is founded aiming to solve the problems that the simplified mechanical model has. Secondly, the boundary of cave roof is simply supposed to be supported according to the integrity of the rock mass in the boundary of cave roof. Thirdly, based on the theory of plates and shells, the simplified model is calculated and the theoretical calculation formula to determine the safe thickness of cave roof under pile tip can be obtained when the edges of the cave roof are simply supported. In the end, the analysis of the practical engineering project proves the feasibility and the rationality of the method which can be a new method to calculate the safe thickness of cave roof under pile tip. 展开更多
关键词 KARST cave roof theory of plates and shells PILE safe thickness
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