简介:Inthepresentarticle,wedealwiththeso-calledoverconvergencephenomenoninCofaslightlymodifiedPost-Widderoperatorofrealvariable,thatiswiththeextensionofitsapproximationpropertiesfromtherealaxisinthecomplexplane.Inthissense,errorestimatesinapproximationandaquantitativeVoronovskaya-typeasymptoticformulaareestablished.
简介:Surfaceoriginatedkinkbandsconsistofanimportantfailuremodeforfibre-reinforcedcompo-sitesundercompression.Themechanicalbehaviorofthefibrebridgingkinkbandsisexploredhereininthecontextofthepost-microbucklingtheory.Expressionsofbridgingforceareobtainedfortheentirepostbucklingprocessofthefibresexhibitingweakorstronghardening.Thepostbucklingformulationofthefibresisappliedtoyieldthetoughnessincrementduetotheadvancingkinkbands,andconsequentlyleadstoaquantitativepre-dictionontheoverallcompressivestressstraincurvesofthefibre-reinforcedcomposites.
简介:Thispaperattemptstoinvestigatethebucklingandpost-bucklingbehaviorsofpiezoelectricnanoplatebasedonthenonlocalMindlinplatemodelandvonKarmangeometricnonlinearity.Anexternalelectricvoltageandauniformtemperatureriseareappliedonthepiezoelectricnanoplate.Boththeuniaxialandbiaxialmechanicalcompressionforceswillbeconsideredinthebucklingandpost-bucklinganalysis.Bysubstitutingtheenergyfunctionsintotheequationoftheminimumtotalpotentialenergyprinciple,thegoverningequationsarederiveddirectly,andthendiscretizedthroughthedifferentialquadrature(DQ)method.Thebucklingandpost-bucklingresponsesofpiezoelectricnanoplatesarecalculatedbyemployingadirectiterativemethodunderdifferentboundaryconditions.Thenumericalresultsarepresentedtoshowtheinfluencesofdifferentfactorsincludingthenonlocalparameter,electricvoltage,andtemperatureriseonthebucklingandpost-bucklingresponses.
简介:Thepost-curekineticsofelectronbeam(EB)curingofepoxyresininitiatedbydiaryiodiniumwasinvestigated.Thepost-curereactionfitsfirstorderreactionkinetics.Thereactionrateconstantincreaseswithincreasingtreatmenttemperatureofpost-cure.Thereactionrateofpost-cureismuchlowerthantherateofitsreactiononelectronbeamtreatment.
简介:Equilibriumpathsofpost-bucklingaremeasuredforlargeslendernesscolumnspecimensmadeofthefiberreinforcedcompositematerial.Theinfluenceoftheinitialcurvatureisinvestigatedexperimentallyandcomparedwiththeresultoftheinitialpost-bucklingtheory.Boththetheoreticalandexperimentalresultsrevealthatthecolumnwiththeinitialcurvaturehasstablepost-bucklingbe-haviorsandisnotsensitivetotheimperfectionintheformofinitialcurvature.Theexperimentalre-sultsshowthatwhenthelateralbucklingdisplacementislessthan20percentofthecolumnlength,theexperimentalresultsagreewiththeresultsfromthetheoryofinitialpost-bucklingquitewell,whiletheyagreewiththeresultsfromthelargedeflectiontheoryinaquitelargerange.
简介:Onthebasisofboththegeneraltheory[1,2]andthefiniteelementmethod[4]ofperforatedthinplateswithlargedeflection,thebucklingandpost-bucklingofannularplatesundernon-axisymmetricplaneedgeforcesarestudied.
简介:Wedemonstrateanovelhigh-accuracypost-fabricationtrimmingtechniquetofine-tunethephaseofintegratedMach–Zehnderinterferometers,enablingpermanentcorrectionoftypicalfabrication-basedphaseerrors.Theeffectiveindexchangeoftheopticalmodeis0.19inourmeasurement,whichisapproximatelyanorderofmagnitudeimprovementcomparedtopreviousworkwithsimilarexcessopticalloss.Ourmeasurementresultssuggestthataphaseaccuracyof0.078radwasachievablewithactivefeedbackcontrol.
简介:AmethodoflocalizationisproposedtolowerthehighorderofequationsinFEMcalcula-tionforthestabilityofacomplexthin-walledstructure.Thelocalizedanalysisenablesustoobtainboththeupperandlowerlimitsforthebifurcatingpointinawholelinearelasticstructuralsystem,aswellasanap-proximatesolutiontoasymptoticpost-bucklingproblem.Somenumericalexamplesareincluded.
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简介:Siliconcarbidefiber/siliconcarbidematrix(SiCf/SiC)compositesareofinterestasafuelcladdingandstructuralmaterialindesignsofadvancednuclearreactorduetotheirsuperiorthermo-mechanicalpropertiesandstabilitiesandlowcross-sectionforneutroncaptureunderthesevereserviceenvironmentincludinghightemperatureandhighenergyneutronbombardment.SiCf/SiCcompositionsconsistsofSiCfiberandSiCmatrixwhichexistinwellover100polymorphsdependentonthevariedstackingofSi-Cclose-packedatomicplanes,2H-SiC,4H-SiC,6H-SiC,3C-SiC,15R-SiC,etc.EnergeticHeatomscanbecreatedandaccumulatedvianuclearreactions.HeatomsagglomerateandcoarsenintoHebubblesandcandeterioratestructuralpropertiesbyinducingcrackandcreep.Inthisexperiment,thedamageofn-type4H-SiCwafers(researchstandard,suppliedbytheCreeResearchInc.)withathicknessof0.38mmimplantedwith100keVHe+toafluenceof31016He+/cm2andpost-implantation-annealedbehavioratdifferenttemperaturewerestudiedusingRamanscatteringspectroscopy.
简介:High-performancethin-filmtransistors(TFTs)withalowthermalbudgetarehighlydesiredforflexibleelectronicapplications.Inthiswork,theTFTswithatomiclayerdepositedZnO-channel/Al_2O_3-dielectricarefabricatedunderthemaximumprocesstemperatureof200℃.First,weinvestigatetheeffectofpost-annealingenvironmentsuchasN_2,H_2-N_2(4%)andO_2onthedeviceperformance,revealingthatO_2annealingcangreatlyenhancethedeviceperformance.Further,wecomparetheinfluencesofannealingtemperatureandtimeonthedeviceperformance.Itisfoundthatlongannealingat200℃isequivalenttoandevenoutperformsshortannealingat300℃.ExcellentelectricalcharacteristicsoftheTFTsaredemonstratedafterO_2annealingat200℃for35min,includingalowoff-currentof2.3×10~(-13)A,asmallsub-thresholdswingof245mV/dec,alargeon/offcurrentratioof7.6×10~8,andahighelectroneffectivemobilityof22.1cm~2/V·s.Undernegativegatebiasstressat—10V,theabovedevicesshowbetterelectricalstabilitiesthanthosepost-annealedat300℃.Thusthefabricatedhigh-performanceZnOTFTwithalowthermalbudgetisverypromisingforflexibleelectronicapplications.