简介:Anacceleratedmicro-foilisusedtoigniteapre-compressedcylindricalshellcontainingdeuterium–tritiumfuel.Thewell-knownshockwaveignitioncriterionandanovelcriterionbasedonheatwaveignitionaredevelopedinthiswork.Itisshownthatforheatignitionveryhighimpactvelocitiesarerequired.Itissuggestedthatamulti-petawattlasercanaccelerateamicro-foiltorelativisticvelocitiesinaveryshorttimeduration(picosecond)ofthelaserpulse.Thecylindricalgeometrysuggestedhereforthefastignitionapproachhastheadvantageofgeometricallyseparatingthenanosecondlasersthatcompressthetargetfromthepicosecondlaserthatacceleratesthefoil.Thepresentmodelsuggeststhatnuclearfusionbymicro-foilimpactignitioncouldbeattainedwithcurrentlyexistingtechnology.
简介:Manynonlinearquantumopticalphysicsphenomenaneedmoreaccuratewavefunctionsandcorrespondingenergyorquasienergylevelstoaccountfor.AnanalyticexpressionofwavefunctionswithcorrespondingenergylevelsforanatomicelectroninteractingwithaphotonfieldispresentedasanexactsolutiontotheSchrSdinger-likeequationinvolvedwithbothatomicCoulombinteractionandelectron-photoninteraction.Thesolutionisanaturalgeneralizationofthequantum-fieldVolkovstatesforanotherwisefreeelectroninteractingwithaphotonfield.ThesolutionshowsthatanN-levelatominlightformstationarystateswithoutextraenergysplittinginadditiontotheFloquetmechanism.Thetreatmentdevelopedherewithcomputingcodescanbeconvenientlytransferredtoquantumopticsinclassical-fieldversionasresearchtoolstobenefitthewholephysicscommunity.
简介:Thisletterpresentsanewanalyticalapproximationforwave(current)-induceddynamicsoilresponseinmarinesediments.Inthemodel,thethird-orderapproximationforwave-currentinteractionsisemployedfortheflowmodel,whileBiot’sdynamicporo-elasticmodelisusedtosimulatetheporousflowinaseabed.Thenewlyanalyticalsolutionisvalidatedwiththefieldobservations.Basedonthesolution,effectsofcurrentsandwave-nonlinearityonsoilresponseareexaminedandaparametricstudywillbecarriedouttoexaminetheinfluenceofcurrentsontheliquefactionpotential.
简介:Inthisarticle,weconsidertheglobalexistenceanddecayratesofsolutionsforthetransmissionproblemofKirchhofftypewaveequationsconsistingoftwophysicallydifferenttypesofmaterials,onecomponentbeingaKirchhofftypewaveequationwithtimedependentlocalizeddissipationwhichiseffectiveonlyonaneighborhoodofcertainpartofboundary,whiletheotherbeingaKirchhofftypeviscoelasticwaveequationwithnonlinearmemory.
简介:Theauthorshaveinventedtheuniqueoceanwavepowerstation,whichiscomposedofthefloatingtypeplatformwithapairofthefloatsliningupattheintervalofonewavepitchandthecounter-rotatingtypewavepowerunit,itsrunnersaresubmergedintheseawateratthemiddlepositionoftheplatform.Suchprofilesmaketheflowvelocityattherunneristwicefasterthanthatofthetraditionalfixed/caissontypeOWC,ontheidealflowconditions.Besides,therunnerscounter-rotatetheinnerandtheouterarmaturesofthepeculiargenerator,respectively,andtherelativerotationalspeedisalsotwicefasterthanthespeedofthesinglerunner/armature.Suchcharacteristicsmaketherunnerdiameterlarge,namelytheoutputhigher,asrequested,becausethetorqueofthepowerunitneveractonthefloatingtypeplatform.Atthepreliminaryreseach,thispaperverifiestogetthepowerusingaWellstypesinglerunnerinstalledinthemodelstation.Therunnertakestheoutputwhichisaffectedbytheoscillatingamplitudeoftheplatform,therotationalspeedandtheinertiaforceoftherunner,etc.
简介:Inthispaper,amathematicalmodelforLovewavepropagationinaporouselasticlayerunderarigidboundaryrestingoveraporo-elastichalf-spacehasbeendeveloped.ThestudyshowsthatsuchamediumtransmitstwotypesofLovewaves.ThefirstfrontdependsonthechangeinvolumefractionoftheporeswhereasthesecondfrontdependsuponthemodulusofrigidityoftheelasticmatrixofthemediumandisthesameastheLovewaveinanelasticlayeroveranelastichalf-space.Itisobservedthatthefirstfrontismanytimesfasterthantheshearwaveinthemediumwithvoidporesduetothechangeinthevolumefractionoftheporesandissignificant.
简介:在一个二维的方形的数组的螺线波浪的开发由于部分离子隧道块(钾,钠)被调查,节点的动力学被HodgkinHuxley神经原描述,这些神经原最近被结合邻居连接。参数比率xNa(并且xK),它定义钠(钾)的工作离子隧道数字的比率到钠的全部的离子隧道数字(并且钾),被用来测量隧道块导致的移动传导力。在二参数的阶段空间(参数比率对毒害的区域)的统计可变R的分发广泛地被计算为部分离子隧道块导致的螺线波浪的转变标记参数区域,有同步R的更小的因素的区域被联系那个螺线波浪使明白毒害的隧道、柔韧的参数区域。当毒害的区域(钾或钠)和沉醉的度是小的时,螺线波浪保持活着,不同转变(死亡,几个螺线波浪共存或多手臂螺线波浪出现)发生在中等比率xNa下面(并且xK)当堵住的区域的尺寸超过某些阀值时。螺线波浪的决裂发生,螺线的多手臂飘动当隧道噪音被考虑时,被观察。
简介:这份报纸涉及多域光谱方法,基于内部惩罚不连续的Galerkin(IPDG)明确的表达,为经由一个准确通报或球形的Dirichlet-to-Neumann(DtN)边界截断的外面的Helmholtz问题调节。一条有效反复的途径被建议本地化全球DtN边界条件,它为scatterers的复杂几何学便于多域方法,和处理的实现。在不连续的Galerkin明确的表达下面,建议方法允许在不同子域上使用不同的度的多项式基础功能,并且更重要地,明确的波浪数字依赖估计光谱计划能被导出,它为多域是以某种方式难以置信的连续Galerkin明确的表达。[从作者抽象]
简介:Theelasticwavepropagationphenomenaintwo-dimensionalperiodicbeamlatticesarestudiedbyusingtheBlochwavetransform.Thenumericalmodelingisappliedtothehexagonalandtherectangularbeamlattices,inwhich,boththein-plane(withrespecttothelatticeplane)andout-of-planewavesareconsidered.ThedispersionrelationsareobtainedbycalculatingtheBlocheigenfrequenciesandeigenmodes.Thefrequencybandgapsareobservedandtheinfluenceoftheelasticandgeometricpropertiesoftheprimitivecellonthebandgapsisstudied.ByanalyzingthephaseandthegroupvelocitiesoftheBlochwavemodes,theanisotropicbehaviorsandthedispersivecharacteristicsofthehexagonalbeamlatticewithrespecttothewavepropagationarehighlightedinhighfrequencydomains.OneimportantresultpresentedhereinisthecomparisonbetweenthefirstBlochwavemodestothemembraneandbending/transverseshearwavemodesoftheclassicalequivalenthomogenizedorthotropicplatemodelofthehexagonalbeamlattice.Itisshownthat,inlowfrequencyranges,thehomogenizedplatemodelcancorrectlyrepresentboththein-planeandout-of-planedynamicbehaviorsofthebeamlattice,itsfrequencyvaliditydomaincanbepreciselyevaluatedthankstotheBlochmodalanalysis.Asanotherimportantandoriginalresult,wehavehighlightedtheexistenceoftheretropropagatingBlochwavemodeswithanegativegroupvelocity,andofthecorresponding'retro-propagating'frequencybands.
简介:Thepropagationofshockwavesinacellularbarissystematicallystudiedintheframeworkofcontinuumsolidsbyadoptingtwoidealizedmaterialmodels,viz.thedynamicrigid,perfectlyplastic,locking(D-R-PP-L)modelandthedynamicrigid,linearhardeningplastic,locking(D-R-LHP-L)model,bothconsideringtheeffectsofstrain-rateonthematerialproperties.Theshockwavespeedrelevanttothesetwomodelsisderived.ConsiderthecaseofabarmadeofoneofsuchmaterialwithinitiallengthL0andinitialvelocityviimpingingontoarigidtarget.Thevariationsofthestress,strain,particlevelocity,specificinternalenergyacrosstheshockwaveandtheceasedistanceofshockwavearealldeterminedanalytically.Inparticularthe'energyconservationcondition'andthe'kinematicexistencecondition'asproposedbyTanetal.(2005)isre-examined,showingthatthe'energyconservationcondition'andtheconsequent'criticalvelocity',i.e.theshockcanonlybegeneratedandsustainedinR-PP-Lbarswhentheimpactvelocityisabovethiscriticalvelocity,isincorrect.Instead,withelasticdeformation,strain-hardeningandstrain-ratesensitivityofthecellularmaterialsbeingconsidered,itisappropriatetoredefineafirstandasecondcriticalimpactvelocityfortheexistenceandpropagationofshockwavesincellularsolids.StartingfromthebasicrelationsforshockwavepropagatinginD-R-LHP-Lcellularmaterials,anewmethodforinverselydeterminingthedynamicstress-straincurveforcellularmaterialsisproposed.Byusinge.g.acombinationofTaylorbarandHopkinsonpressurebarimpactexperimentaltechnique,thedynamicstress-straincurveofaluminumfoamcouldbedetermined.Finally,itisdemonstratedthatthisnewformulationofshocktheoryinthisone-dimensionalstressstatecanbegeneralizedtoshocksinaone-dimensionalstrainstate,i.e.forthecaseofplateimpactoncellularmaterials,bysimplymakingproperreplacementsoftheelasticandplasticconstant
简介:Controlofthespatiotemporalpatternsnearthecodimension-threeTuring–Hopf–Wavebifurcationsisstudiedbyusingtime-delayedfeedbackinathree-variableBrusselatormodel.LinearstabilityanalysisofthesystemshowsthatthecompetitionamongtheTuring-,Hopf-andWave-modes,thewavenumber,andtheoscillationfrequencyofpatternscanbecontrolledbychangingthefeedbackparameters.TheroleofthefeedbackintensityPuplayedoncontrollingthepatterncompetitionisequivalenttothatofPw,butoppositetothatofPv.TheroleofthefeedbackintensityPuplayedoncontrollingthewavenumberandoscillationfrequencyofpatternsisequivalenttothatofPv,butoppositetothatofPw.Whentheintensitiesoffeedbackareappliedequally,changingthedelayedtimecouldnotalterthecompetitionamongthesemodes,however,itcancontroltheoscillationfrequencyofpatterns.Theanalyticalresultsareverifiedbytwo-dimensional(2D)numericalsimulations.
简介:Analyticalsolutionsfortheflexural-gravitywaveresistancesduetoalinesourcesteadilymovingonthesurfaceofaninfinitelydeepfluidareinvestigatedwithintheframeworkofthelinearpotentialtheory.Thehomogenousfluid,coveredbyathinelasticplate,isassumedtobeincompressibleandinviscid,andthemotiontobeirrotational.ThesolutioninintegralformforthewaveresistanceisobtainedbymeansoftheFouriertransformandtheexplicitlyanalyticalsolutionsarederivedwiththeaidoftheresiduetheorem.Thedispersionrelationshowsthatthereisaminimalphasespeedcmin,athresholdfortheexistenceofthewaveresistance.NowaveisgeneratedwhenthemovingspeedofthesourceVislessthancminwhilethewaveresistancesfirstlyincreasetotheirpeakvaluesandthendecreasewhenVcmin.Theeffectsoftheflexuralrigidityandtheinertiaoftheplatearestudied.