简介：Withtheadvantagesoftransmittingenergyfrommultipledirectionstoonedirectionandtransformingvibrationfromonesourcetomultipledirections,thetwo-dimensionalvibrationdirectionconverterhasimportantapplicationsinpowerultrasonictechnology.However,forthecomplexityofusingthewaveequationtodesignandanalysisthetwo-dimensionalvibrationdirectionconverter,aconciseequivalentcircuitfortheconverterisinvestigated.Byintroducingthetwo-dimensionalmechanicalcouplingcoefficientandthelongitudinalforcetransformcoef-ficient,andusingtheelectromechanicalanalogyprinciple,theequivalentcircuitandresonancefrequencyequationofthetwo-dimensionalvibrationdirectionconvertervibratinginanti-phaseandin-phasetwo-dimensionalcoupledvibrationarededuced.Theresonancefrequenciesofthevibrationdirectionconvertersoftwodifferentmaterialsarecalculatedbyusingtheproposedfrequencyequation,whichareinagreementwiththeresultsfromthefiniteelementmethodandtheexperimentaltest.Itprovidesaconcisemethodforthedesignandapplicationsofsuchultrasonicvibrationsystem.

简介：ThispaperinvestigatestheevolutionarychangeintheOF(OF)ofhedgesindifferentmovesofEMRAs(EMRAs).Twocorporaareestablishedforlongitudinalstudy,withCorpusAconsistingofEMRAsfrom1990-1994andCorpusBfrom2005-2009.Generally,nosignificantchangehasbeenfoundinoveralluseofhedges.However,apartfrommove6,7and10,wehavefoundsomeinterestingchangesintheothermoves.Ontheonehand,theOFofhedgesinmove1,move3,move4andmove5showsasignificantincrease.Ontheotherhand,theOFofhedgesinmove2,8,9andmove11showasignificantdecrease.

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简介：空间关联系数是为对浅水里的健全繁殖的描述的最重要的参数之一。纵的关联长度的频率依赖仍然是一个开的话题。我们在一个浅水实验观察到以波长的单位的纵的关联长度随频率的增加增加。这现象没在出版报纸被看见。理论分析和数字模拟显示底部变细的非线性的频率关系是这现象的主要原因。

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简介：TheLongitudinalAerodynamicCharacteristics(LACs)ofawing-bodywithouttailunitiscomputedandtestedinwindtunnel.TheempiricalformulasofDatcomandsomeotherauthorsareappliedtoestimatethebasicAerodynamicCoefficients.Twowingoptionsarecoveredasanalysisspace,namely,thedouble-deltawingandstreakwing,gettingtwoanalysisgroupsrespectively.Goodagreementbetweenthecomputationresultsandthewindtunneltestsshowsthatthemethodologypresentedisasimpleandreliablewaytocalculatethiskindofnovelwing-bodyconfigurations.

简介：Theinteractionbetweenlongitudinalvorticesandflatplateboundarylayerhasbeenstudiednumericallyforbothlaminarandturbulentflowsituations.Thevorticesareassumedtobeplacedinanotherwisetwo-dimensionalboundarylayerflow.Theflowisassumedtobeincompressibleandsteady.Consid-eringthefactthatthevelocity,vorticityandtemperaturegradientsinthetransversedirectionsaremuchlargerthanthelongitudinal(streamwise)gradientsfortheseflows,theoriginalNavierStokesequationsareparabolizedinthestreamwisedirection.Asimplemodel,basedonBoussinesqhypothesis,isusedforturbu-lentflow.Thediscretizedequationsarethensolvedstepbystepinthestreamwisedirection,usinganiterativeprocedureateachstation.Numericalsolutionshavebeenobtainedfordifferentparameters,suchastheReynoldsnumber,thecirculationandtheinitialpositionofthevortices.ThecomputedflowpatternsandtheskinfrictioncoefficientandStantonnumberarefoundtobequalitativelyconsistentwithavailableexperimentalresults.Itisshownthattheinteractionbetweenthevorticesandtheboundarylayermayseverelydisturbtheboundarylayerflowfieldandthusconsiderablyincreasethelocalskinfrictionandheattransferrateonsurfaceofanaircraft.

简介：Laboratoryexperimentsonlongitudinaldispersioninclear-waterandsediment-ladenopenchannelflowsarereported.Datafromtheseexperimentsandthoseavailablefrompreviousstudiesindicatethatthesuspendedsedimentpresentintheflowaffectsthelongitudinaldispersionprocess.Theobservedvelocitydistributionsoverthedepthofsediment-ladenflowsindicatethatthevelocitydeviatesfromthemeanvelocitymoreinsediment-ladenflowsthaninclear-waterflows.Thevelocitydistributionsoverthecrosssectionandsecondaryflowinthechannelarealsoexpectedtobealteredduetothepresenceofsuspendedsedimentsintheflow.Forthesereasons,moredispersionisfoundinsediment-ladenflowsthanincorrespondingclear-waterflows.Apredictorforthedispersioncoefficientinsediment-ladenflowsisproposed.

简介：Anovelpre-ionizationschemeofhelicaltransverse-pulsedpre-ionizationinalongitudinaldischargeCO2laserispresented.Thelasertubeismadeofglasswithinnerdiameterof7.5mmanddischargelengthof50cm.Thelaserperformancecharacteristicsasfunctionsofparameters,suchaspressure,chargingcapacitanceandappliedvoltage,areinvestigated.Comparedwiththesamelaserstructurewithoutpre-ionization,themaximumpulseenergyimprovesby23%,theoptimumelectro-opticalefficiencyincreasesby31%,andthespecificoutputenergyreaches26J/(L·atm).

简介：在有卡住大头针的边界条件的非局部的nanobeams的postbuckling配置附近的非线性的免费颤动是调查的经分解，认为从中间飞机的拉长并且特别地产生的几何非线性是一个纵的磁场的效果。当应用轴的力量是小的时，nanobeam是稳定的，它的免费颤动在直平衡位置附近。当轴的力量变得大并且在某个批评价值(批评轴的力量)以外，然而，积极或否定的重要平衡配置发生，免费颤动在弄弯的配置附近。当为弄弯的nanobeam它包含立方、二次的非线性时，为在弄弯前的nanobeam的管理方程展出立方的非线性。基于非线性的管理方程，postbuckling配置的近似分析解决方案以应用轴的力量被评估，证明磁场参数在批评轴的力量，弄弯的排水量和nanobeam系统的线性频率上有大效果。更有趣地，当它能是比在postbuckling政体的情况中的线性的低的时，非线性的频率被发现通常比在prebuckling政体的情况中的线性频率高。非线性的频率能被磁场，与中间飞机的拉长联系的非线性的系数，和起始的颤动振幅显著地影响。

简介：Thevibrationproblemofapileofarbitrarysegmentswithvariablemodulusunderexcitingforceisestablished,inwhichtheinfluenceofthesoilunderpiletoeandthesurroundingsistakenintoaccount.WithLaplacetransforms,thetransmitfunctionsforvelocityanddisplacementofpilearederived.Furthermore,intermsoftheconvolutiontheoremandinversedLaplacetransform,ananalyticalsolutionforthetimedomainresponseofapilesubjectedtoasemi-sineimpulseisdeveloped,whichisthetheoreticalbasisofthesonicmethodinpileintegritytesting.Basedonthesolution,thevibrationpropertiesofpilewithsharporcontinuousmodulusarestudied.Thevalidityofthisapproachisverifiedthroughfidddynamictestsonsomeengineeringpiles.Itshowsthatthetheoreticalpredictionandtheresponseofthepileareingoodagreement.

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简介：Metaltransferisanimportantphenomenoninmetalinertgas(MIG)arcweldingwithlongitudinalalternatingmagneticfield.Itisofgreatsignificancetoobservethemetaltransfermodesunderdifferentexcitatorycurrentsandfrequencies.However,itisverydifficulttoviewthemetaltransferprocessdirectlyduringwelding,duetothestronginterferencefromthearclight.Toobtaintherelationshipbetweenthemetaltransfermodesandthedifferentmagneticfields,ahigh-speedvideocamerawasusedtoacquiretheimagesofglobules.Differentmetaltransfermodesundertheconditionsofdifferentmagneticfieldsandweldingparameterswerestudied.Theexperimentshowsclearimagesofdroplettransferaswellasinfluenceoflongitudinalmagneticfieldonbothmetaltransferandglobuleshape.

简介：TheuseofabackgroundplasmainadielectricCherenkovmasercaneffectivelyincreasetheefficiencyandthemicrowaveoutputpowerofthedevice.Here,theeffectofthelongitudinaluniformmagneticfieldonthewave-beaminteractionoftheplasma-filleddielectricCherenkovmaserisexaminedbysolvingthebeam-plasma,dielectriclinedwaveguidedispersionequation.Andtheeffectsofthelongitudinalmagneticfield,plasmadensityanddielectricparametersonthelinearspatialgrowthrateandtheenergyratioarepresented.

简介：Inthispaperweuseprofileempiricallikelihoodtoconstructconfidenceregionsforregressioncoefficientsinpartiallylinearmodelwithlongitudinaldata.Themaincontributionisthatthewithin-subjectcorrelationisconsideredtoimproveestimationefficiency.Wesupposeasemi-parametricstructureforthecovariancesofobservationerrorsineachsubjectandemployboththefirstorderandthesecondordermomentconditionsoftheobservationerrorstoconstructtheestimatingequations.Althoughtherearenonparametricestimators,theempiricallog-likelihoodratiostatisticstilltendstoastandardχ2pvariableindistributionafterthenuisanceparametersareprofiledaway.Adatasimulationisalsoconducted.

简介：Thispaperproposesanewapproachforvariableselectioninpartiallylinearerrors-in-variables(EV)modelsforlongitudinaldatabypenalizingappropriateestimatingfunctions.WeapplytheSCADpenaltytosimultaneouslyselectsignificantvariablesandestimateunknownparameters.Therateofconvergenceandtheasymptoticnormalityoftheresultingestimatorsareestablished.Furthermore,withproperchoiceofregularizationparameters,weshowthattheproposedestimatorsperformaswellastheoracleprocedure.Anewalgorithmisproposedforsolvingpenalizedestimatingequation.Theasymptoticresultsareaugmentedbyasimulationstudy.

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简介：Thispaperinvestigatesthedamagedetectionbasedonthepropagationofguidedwaveinbimetalcompositepipes,whichcanidentifydamagelocationsinbothaxialandcircumferentialdirections.ThefeasibilityofthemethodisshowedbynumericalsimulationsusingFEMcodeANSYS.Modeanalysisisusedtoevaluatetheguidedwavemodeanditsstructure,whichcanprovidethebasisofthemodeselectioninmeasurementsscheme.Theguidedwavepropagationinadamagedpipeiscomputedbytransientanalysis.16...

简介：Theresonancefrequenciesandstabilityofananobeaminalongitudinalmagneticfieldareinvestigated.Tothisaim,athreedimensionalbeammodelisusedinwhichthesmall-scaleeffectistakenintoaccountbasedonthenonlocalelasticitytheory.TheLorentzforcesareobtainedintermsofthelocalelasticrotationsofthebeamandthethermalstressduetocurrentismodeledasanaxialcompressiveforce.UsingtheGalerkinmethod,thegoverningequationsofmotionaresolvedandthestabilityboundaryofthenanobeamisdetermined.