简介：Neutralbeaminjection(NBI)isrecognizedasoneofthemosteffectivemeansforplasmaheating.A100slongpulseneutralbeamwith30keVbeamenergy,10Abeamcurrentanda100slongpulsemodulatingneutralbeamwith50keVbeamenergy,16AbeamcurrentwereachievedintheEASTneutralbeaminjectoronthetest-stand.ThepreliminaryresultssuggestthatEAST-NBIsysteminitiallypossesstheabilityoflongpulsebeamextraction.

简介：OfconcernisaviscoelasticbeammodelledusingtheTimoshenkotheory.Itiswell-knownthatthesystemisexponentiallystableifthekernelinthememorytermissub-exponential.Thatis,iftheproductofthekernelwithanexponentialfunctionisasummablefunction.Inthisarticleweaddressthequestions:Whatifthekernelistestedagainstadifferentfunction(sayGamma)otherthantheexponentialfunction?Wouldtherestillbestability?Intheaffirmative,whatkindofdecayrateweget?Itisprovedthatforanon-decreasingfunction'Gamma'whose'logarithmicderivative'isdecreasingtozerowehaveadecayoforderGammatosomepowerandinthecaseitdecreasestoadifferentvaluethanzerothenthedecayisexponential.

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简介：Beampositioningstabilityinalaser-driveninertialconfinementfusion(ICF)facilityisavitalproblemthatneedstobefixed.Eachlaserbeaminthefacilityistransmittedinlotsofopticsforhundredsofmeters,andthentargetedinamicro-sizedpellettorealizecontrollablefusion.Anyturbulenceintheenvironmentinsuchlong-distancepropagationwouldaffectthedisplacementofopticsandfurtherresultinbeamfocusingandpositioningerrors.Thisstudyconcludedthattheerrorsoneachoftheopticscontributedtothetarget,anditpresentsanefficientmethodofenhancingthebeamstabilitybyeliminatingerrorsonerror-sensitiveoptics.Optimizationsoftheopticalsystemandmechanicalsupportingstructuresarealsopresented.

简介：Thispaperpresentsthevibrationssuppressionofathermoelasticbeamsubjecttosuddenheatinputbyasinglepiezoelectricactuator.Anoptimizationproblemisformulatedastheminimizationofaquadraticfunctionalintermsofdisplacementandvelocityatagiventimeandwiththeleastcontroleffort.Thesolutionmethodisbasedonacombinationofmodalexpansionandvariationalapproaches.Themodalexpansionapproachisusedtoconverttheoptimalcontrolofdistributedparametersystemintotheoptimalcontroloflumpedparametersystem.Byutilizingthevariationalapproach,anexplicitoptimalcontrollawisderivedandthedeterminationofthecorrespondingdisplacementandvelocityisreducedtosolvingasetofordinarydifferentialequations.Numericalresultsarepresentedtodemonstratetheeffectivenessandtheapplicabilityoftheproposedmethod.

简介：Anovelmethodfordesigningabeam-switchingantennawiththeplanedipoleispresented.Theantennaiscomposedofdoubledipolesplacedatthecenterofanactivesquarestructurethatisdividedinfourequalsectorsbymetallicsheets.Metallicpatchesattheoutsideofthestructureareusedtoenhancetheradiationperformanceoftheantenna.Ineachstep,thediodesinonesectorareon,whereasotherdiodesareoff.Thesectorwithoff-statediodesdefinesthedirectionoftheradiationpattern.AnantennamodelisdesignedonthesubstrateofFR4.Theproposedantennaoperatesfrom4.8GHzto5.5GHzwithgainof6.3dBiandF/B(fronttobackratio)of13.2dBiwhentheoperatingfrequencyis5.2GHz.Theantennaradiationpatterncanbesweptintheentireazimuthplaneinfourstepswitha3dBbeamwidthof90.Theresultsrevealthattheantennacouldbeusedinthebasestationofthewirelesscommunicationsystems.

简介：在这研究，为评估自然频率和模式的准确解决方案的分析关系与嵌入的形状存储器横梁塑造合金(SMA)电线被介绍。横梁根据Euler-Bernoulli，Timoshenko和第三根顺序横梁(瑞迪)理论被建模。一种关系为决定预先拉紧的SMA电线的恢复行动产生的轴的负担的效果被获得。由定义一些无尺寸的数量，频率和系统的模式形状上的不同机械性质的效果小心地被检验。轴的负担的效果与弄弯由SMA电线产生了负担和频率跳精确地被学习。

简介：模式跳是在buckling以后区域的不稳定性现象，它在平衡配置引起一个突然的变化并且因此是有害的组织。一个部分有弹性的基础的配置能直接导致模式从弄弯的阶段并且通过整个buckling以后区域联合。在模式跳上由于部分基础的配置联合效果的模式被调查并且示威了是决定模式跳的一个重要因素。由适当地选部分有弹性的基础为配置，模式跳能被避免。

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简介：ThepresentpaperinvestigatesthedynamicresponseoffiniteTimoshenkobeamsrestingonasixparameterfoundationsubjectedtoamovingload.ItisforthefirsttimethattheGalerkinmethodanditsconvergencearestudiedfortheresponseofaTimoshenkobeamsupportedbyanonlinearfoundation.ThenonlinearPasternakfoundationisassumedtobecubic.Therefore,theefectsofthesheardeformablebeamsandthesheardeformationoffoundationsareconsideredatthesametime.TheGalerkinmethodisutilizedfordiscretizingthenonlinearpartialdifferentialgoverningequationsoftheforcedvibration.ThedynamicresponsesofTimoshenkobeamsaredeterminedviathefourth-orderRunge–Kuttamethod.Moreover,theefectsofdiferenttruncationtermsonthedynamicresponsesofaTimoshenkobeamrestingonacomplexfoundationarediscussed.ThenumericalinvestigationsshowsthatthedynamicresponseofTimoshenkobeamssupportedbyelasticfoundationsneedssuperhigh-ordermodes.Furthermore,thesystemparametersarecomparedtodeterminethedependenceoftheconvergencesoftheGalerkinmethod.

简介：Forafinitebeamwithanonzerogapdistance,anasymmetricconcentratedloadcanbeeitherinsideoroutsideofthecontactzone.Anewgoverningequationisgivenforthecaseofaconcentratedloadoutsidethecontactzone.Bynumericallysolvingtheleft-sideandright-sidecontactlengthsofthebeam,acriterionisestablishedtodeterminewhethertheconcentratedloadisinsideoroutsidethecontactzone.Amoregeneralapproachonthetensionlesscontactofabeamisthuspresented.

简介：Wereviewtheuseofhollow-corephotoniccrystalfibre(HC-PCF)forhighpowerlaserbeamdelivery.AcomparisonofbandgapHC-PCFwithKagome-latticeHC-PCFonthegeometry,guidancemechanism,andopticalpropertiesshowsthattheKagome-typeHC-PCFisanidealhostforhighpowerlaserbeamtransportationbecauseofitslargecoresize,lowattenuation,broadbandtransmission,single-modeguidance,lowdispersionandtheultra-lowopticaloverlapbetweenthecore-guidedmodesandthesilicacore-surround.ThepowerhandlingcapabilityofKagome-typeHC-PCFisfurtherexperimentallydemonstratedbymillijoulenanosecondlasersparkignitionand~100μJsub-picosecondlaserpulsetransportationandcompression.

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简介：Aconvenientanduniversalresiduecalculusmethodisproposedtostudythestochasticresponsebehaviorsofanaxiallymovingviscoelasticbeamwithrandomnoiseexcitationsandfractionalorderconstitutiverelationship,wheretherandomexcitationcanbedecomposedasanonstationarystochasticprocess,Mittag-Lefflerinternalnoise,andexternalstationarynoiseexcitation.Then,basedontheLaplacetransformapproach,wederivedthemeanvaluefunction,variancefunctionandcovariancefunctionthroughtheGreen'sfunctiontechniqueandtheresiduecalculusmethod,andobtainedtheoreticalresults.Insomespecialcaseoffractionalorderderivativeα,theMonteCarloapproachanderrorfunctionresultswereappliedtochecktheeffectivenessoftheanalyticalresults,andgoodagreementwasfound.Finallyinageneral-purposecase,wealsoconfirmedtheanalyticalconclusionviathedirectMonteCarlosimulation.

简介：自从增强的水泥(RC)的很当前的地震能力评估，框架结构被任何一个静电干扰闲差事分析(PA)或动态时间历史分析实现，与象柱，横梁和墙的如此的主要结构的部件上的塑料绞链(PH)的多样的背景，复杂行为砍在横梁列关节(BCJ)的失败通常在主要地震期间被忽视。这研究建议新非线性的PA过程考虑砍在BCJ的失败并且寻求估计实际损坏到RC结构。基于FEMA-356的说明，由在塑料绞链的地点上斜放的二口非线性的生气神气组成的一个简化联合模型被建立，允许复杂PA被表现。为了验证这个方法，能力曲线的分析结果和失败的有效性，机制源于框架与试验性的大小相比的三不同动物完全长大的RC。由考虑砍在BCJ的失败，建议非线性的分析过程能被用来估计RC框架的结构的行为包括地震能力和关节的进步失败顺序，以一种精确、有效的方式。

简介：AlONnanolayersaresynthesizedonAlsubstratebytheirradiationofenergeticnitrogenionsusingplasmafocusing.Samplesareexposedtomultiple(5,10,15,20and25)focusshots.Ionenergyandionnumberdensityrangefrom80keVto1.4MeVand5.6×1019m-3to1.3×1019m-3,respectively.Moreover,theefectofcontinuousannealing(473Kand523K)onanAlNsurfacelayersynthesizedwith25focusshotsisalsoexamined.ThemainfeaturesoftheX-raydifraction(XRD)patternswithincreasingfocusshotsare:(i)variationinthecrystallinityofAlNalong(111),(200)and(311)planes,(ii)increasingaveragecrystallitesizeofAlN(111)plane,and(iii)stressrelaxationobservedinAlN(111)and(200)planes.ThecrystallinityofAlNsurfacelayeriscomparativelybetterat473Kannealingtemperature.Abroadeneddifractionpeakrelatedtoanaluminiumoxidephaseshowingweakcrystallinityisobservedfor15focusshotswhilenon-boundedoxidesarepresentinallotherdepositedlayers.RamanandFouriertransforminfraredspectroscopy(FTIR)analysisconfirmthepresenceofAlNandAl2O3forthesurfacelayerannealedat473Ktemperature.RamananalysisshowsthattheoverlappingofAlNandAl2O3resultsinthedevelopmentofresidualstresses.Scanningelectronmicroscope(SEM)resultsdemonstratethattheformationofroundedgrains(rangefrom20nmto200nm)andvariationsintheirmicrostructuresfeaturesdependontheincreasingnumberoffocusshots.Decompositionoflargerclustersintosmalleronesisobserved.

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：Anovelmodelisproposedwhichcomprisesofabeambridgesubjectedtoanaxialloadandaninfiniteseriesofmovingloads.Themovingloads,whosedistancebetweentheneighbouringonesisthelengthofthebeambridge,coupledwiththeaxialforcecanleadthevibrationofthebeambridgetocodimension-twobifurcation.Ofparticularconcernisaparameterregimewherenon-persistencesetregionsundergoatransitiontopersistenceregions.Theboundaryofeachstriperepresentsabifurcationwhichcandrivethesystemoffakindofdynamicsandjumptoanotherone,causingdamageduetotheresultingamplitudejumps.TheGalerkinmethod,averagingmethod,invertiblelineartransformation,andnearidentitynonlineartransformationsareusedtoobtaintheuniversalunfoldingforthecodimension-twobifurcationofthemid-spandeflection.Theefficiencyofthetheoreticalanalysisobtainedinthispaperisverifiedvianumericalsimulations.

简介：Inthisstudy,wedevelopedageneralmethodtoanalyticallytackleakindofmovableboundaryproblemfromtheviewpointofenergyvariation.Havinggroupedtheadhesionofamicro-beam,dropletandcarbonnanotube(CNT)ringonasubstrateintooneframework,weusedthedevelopedlineofreasoningtoinvestigatetheadhesionbehaviorsofthesesystems.Baseduponthederivedgoverningequationsandtransversalityconditions,explicitsolutionsinvolvingthecriticalparametersandmorphologiesforthethreesystemsaresuccessfullyobtained,andthentheparameteranalogiesandcommoncharacteristicsofthemarethoroughlyinvestigated.Thepresentedmethodhasbeenverifiedviatheconceptofenergyreleaserateinfracturemechanics.Ouranalysesprovideanewapproachforexploringthemechanismofdifferentsystemswithsimilaritiesaswellasforunderstandingtheunityofnature.Theanalysisresultsmaybebeneficialforthedesignofnano-structuredmaterials,andholdpotentialforenhancingtheirmechanical,chemical,opticalandelectronicproperties.