学科分类
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3 个结果
  • 简介:Leaderpropagationisafundamentalissueinlightningphysics.Thepropagationcharacteristicsofpositiveleadersandnegativeleadersaresummarizedandcomparedbasedondatafromhigh-speedcameraandelectromagneticfieldinrocket-triggeredlightningandtower-initiatedlightningdischarges;availablechannelbasecurrentdatarecordedinrocket-triggeredlightningarealsoused.Thenegativeleaderspropagateinasteppedfashionaccompaniedbymanybranches.Thestemsaheadofthenegativeleadertipdeterminethemanneranddirectionoftheleaderpropagation,andeventhebranchingandwindingofthelightningchannel.Theimpulsivecurrent,electromagneticfield,andrelatedopticalimagessuggestthatthepositiveleadermaydevelopinastep-likefashionatitsinitialstageoftriggeredlightning.However,thesteppingprocessesofthepositiveleaderareobviouslydifferentfromthoseofthenegativeleader.Tower-initiatedlightningrevealedthatthemostconspicuouscharacteristicsofthestepwisepositiveleaderinvolvetheintermittentbrush-likecoronazoneinfrontoftheleadertipandtheluminosityenhancementofthechannelbehindthetip.Inrockettriggeredlightningflashes,thechargetransferredduringanindividualstepforthenegativeleaderwasnearlyanordergreaterthanforthepositivecounterpart.Thesuccessivestreamersaheadoftheleadertipareessentialforbothnegativeandpositiveleaderpropagation,andthestemscouldbeformedfromoneormorestreamersinthepreviousnegativestreamerzonewiththemainleaderchanneldim.High-resolutionobservationoftowerlightningalsorevealedanewtypeofbidirectionalrecoilleader,withpolaritycontrarytothetraditionalone,traversinginnegativechannelsassociatedwithtower-initiatedandrocket-triggeredlightning.

  • 标签: LIGHTNING PROPAGATION NEGATIVE LEADER POSITIVE LEADER
  • 简介:处于在边界随机刺激下面的飞机紧张状态的压电的厚壳的随机的反应与压电的圆柱的壳被学习并且说明。为电的潜力的微分方程放射状地是综合的作为排水量的功能获得电的潜力。随机的压力边界条件被转变变换成同类的,它在随机的刺激下面为排水量产出电、机械的联合微分方程。然后,这个部分微分方程用Galerkin方法和Legendre多项式被变换成平常的微分方程,它与不对称的僵硬矩阵代表一个随机的multi-degree-of-freedom系统由于电、机械联合并且转变边界条件。频率反应功能矩阵和反应力量光谱系统的密度矩阵基于随机的颤动的理论被导出。吝啬平方的排水量和压电的壳的电的潜力最后被获得,并且频率反应特征和电、机械的联合性质被探索。

  • 标签: 管道运输流程 环形流程 稳定性 振动