简介:Amorphouscarbonandgrapheneco-modifiedLiFePO4nanocompositehasbeensynthesizedviaafacilepolyolprocessinconnectionwithafollowingthermaltreatment.Variouscharacterizationtechniques,includingXRD.Mossbauerspectra,Ramanspectra,SEM,TEM,BET,O2-TPO,galvanocharge-discharge,CVandEISwereappliedtoinvestigatethephasecomposition,carboncontent,morphologicalstructureandelectrochemicalperformanceofthesynthesizedsamples.TheeffectofintroducingwayofcarbonsourcesonthepropertiesandperformanceofLiFePO4/C/graphenecompositewaspaidspecialattention.Underoptimizedsyntheticconditions,highlycrystalizedolivine-typeLiFePO4wassuccessfullyobtainedwithelectronconductiveFe2PandFePasthemainimpurityphases.SEMandTEManalysesdemonstratedthegraphenesheetswererandomlydistributedinsidethesampletocreateanopenstructuredLiFePO4withrespecttographene,whiletheglucosederivedcarbonmainlycoatedoverLiFeP04particleswhicheffectivelyconnectedthegraphenesheetsandLiFePO4particlestoresultinamoreefficientchargetransferprocess.Asaresult,favorableelectrochemicalperformancewasachieved.Theperformanceoftheamorphouscarbon-grapheneco-modifiedLiFePO4wasfurtherprogressivelyimproveduponcyclinginthefirst200cyclestoreachareversiblespecificcapacityashighas97mAh·g-1at10Crate.
简介:WithvonMisesyieldcriterion,theloadingrangeofNetSectionCollapse(NSC)Criteriaisextendedfromcombinedtensionandbendingloadingstocombinedbending,torsionandinternalpressureloadings.AnewtheoreticalanalyzingmethodofplasticlimitloadforpressurepipewithincompleteweldingdefectsbasedontheextendedNSCCriteriaispresentedandthecorrelativeformulasarededuced,theinfluencesofpipecurvature,circumferentiallengthanddepthofincompleteweldingdefectsontheplasticlimitloadofpressurepipeareconsideredaswellinthismethod.Meanwhile,accordingtotheorthogonalexperimentaldesignmethod,theplasticlimitloadsarecalculatedbythefiniteelementmethodandcomparedwiththetheoreticalvalues.Theresultsshowthattheexpressionsofplasticlimitloadofpressurepipewithincompleteweldingdefectsunderbending,torsionandinternalpressurebasedonextendedNSCcriteriaarereliable.Thestudyprovidesanimportanttheoreticalbasisfortheestablishmentofsafetyassessmentmeasuretowardspressurepipewithincompleteweldingdefects.
简介:TheLHCDantennathatwillbeusedinHL-2AistheoriginaloneusedinHL-1M,whichwillbemodified.Wemeasuredthefeatureoftheantenna.Thefeaturesincludethereflectionofmainwaveguide,VSWR,theadjacentphrasingbetweenthesub-waveguidesandsoon.Thepaperdescribesthemeasuredresultsandspectrumcalculationbasedonthemeasuredparameters.FromtheworkswecanappreciateourantennacorrectlywhichwillbeusefulforLHCDexperimentonHL-2Aintheyear.
简介:Asahighspecificspeedpump,thecontra-rotatingaxialflowpumpdistinguishesitselfinarearrotorrotatingintheoppositedirectionofthefrontrotor,whichremarkablycontributestotheenergyconversion,thereductionofthepumpsize,betterhydraulicandcavitationperformances.However,withtworotorsrotatingreversely,thesignificantinteractionbetweenbladerowswasobservedinourprototypecontra-rotatingrotors,whichhighlyaffectedthepumpperformancecomparedwiththeconventionalaxialflowpumps.Consequently,anewtypeofrearrotorwasdesignedbytherotationalspeedoptimizationmethodologywithsomeadditionalconsiderations,aimingatbettercavitationperformance,thereductionofbladerowsinteractionandthesecondaryflowsuppression.Thenewrearrotorshowedasatisfactoryperformanceatthedesignflowratebutanunfavorablepositiveslopeofthehead-flowratecurveinthepartialflowraterangelessthan40%ofthedesignflowrate,whichshouldbeavoidedforthereliabilityofpump-pipesystems.Inthepresentresearch,tounderstandtheinternalflowfieldofnewrearrotoranditsrelationtotheperformancesatthepartialflowrates,thevelocitydistributionsattheinletsandoutletsoftherotorsarefirstlyinvestigated.Then,theboundarylayerflowsonrotorsurfaces,whichclearlyreflectthesecondaryflowinsidetherotors,areanalyzedthroughthelimitingstreamlineobservationsusingthemulti-coloroil-filmmethod.Finally,theunsteadynumericalsimulationsarecarriedouttounderstandthecomplicatedinternalflowstructuresintherotors.
简介:Inlostpaperofmagneto-hydrodynamicinstabilityanalysisofliquidmetalfreesurfacejetflow(PartⅠ),themagneto-hydrodynamicinstabilitywasanalyzedforthejetflowinatransversenon-uniformmagneticfield,BT.But,asallknown,fortherealconditionsofliquidmetallimiter-divertorplasma-facingcomponentsareintoroidalandpoloidalfields.So,wetrytoanalyzethemagneto-hydrodynamicinstabilityofthejetflow(herebyonlyforcircularshapecrosssectionjetflow)inthezoneofnon-uniformmagneticfields,
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简介:Structuralhealthmonitoring(SHM)isarelevanttopicforcivilsystemsandinvolvesthemonitoring,dataprocessingandinterpretationtoevaluatetheconditionofastructure,inordertodetectdamage.Inrealstructures,twoormoresitesortypesofdamagecanbepresentatthesametime.Ithasbeenshownthatonekindofdamagedconditioncaninterferewiththedetectionofanotherkindofdamage,leadingtoanincorrectassessmentaboutthestructurecondition.Identifyingcombineddamageonstructuresstillrepresentsachallengeforconditionmonitoring,becausethereliableidentificationofacombineddamagedconditionisadifficulttask.Thus,thisworkpresentsafusionofmethodologies,whereasinglewavelet-packetandtheempiricalmodedecomposition(EMD)methodarecombinedwithartificialneuralnetworks(ANNs)fortheautomatedandonlineidentification-locationofsingleormultiple-combineddamageinascaledmodelofafive-baytruss-typestructure.Resultsshowedthattheproposedmethodologyisveryefficientandreliableforidentifyingandlocatingthethreekindsofdamage,aswellastheircombinations.Therefore,thismethodologycouldbeappliedtodetection-locationofdamageinrealtruss-typestructures,whichwouldhelptoimprovethecharacteristicsandlifespanofrealstructures.
简介:Inthispaper,adetailedLiesymmetryanalysisofthe(2+1)-dimensionalcouplednonlinearextensionofthereaction-diffusionequationispresented.Thegeneralfinitetransformationgroupisderivedviaasimpledirectmethod,whichisequivalenttoLiepointsymmetrygroupactually.Similarityreductionandsomeexactsolutionsoftheoriginalequationareobtainedbasedontheoptimalsystemofone-dimensionalsubalgebras.Inaddition,conservationlawsareconstructedbyemployingthenewconservationtheorem.
简介:Thispaperusesfiniteelementmethodtoobtainthethree-dimensionaltemperaturefieldoflaser-inducedtransientthermalgrating(TTG)fortwo-layeredstructureofdiamondfilmonZnSesubstrate.Thenumericalresultsindicatethatuniquetwo-timesheatingprocessisgraduallyexperiencedintheareabetweentwoadjacentgratingstripes.However,thereisalittlechangeforthetemperaturefieldalongthedepthdirectionforthediamondfilmduetoitsgreatthermalconductivity.Itfurtherfindsthatthethicknessofthediamondfilmhasasignificantinfluenceonthetemperaturefieldindiamond/ZnSesystem.Theresultsareusefulfortheapplicationoflaser-inducedTTGtechniqueinfilm/substratesystem.
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简介:Thispaperdiscussesastatisticalsecond-ordertwo-scale(SSOTS)analysisandcomputationforaheatconductionproblemwitharadiationboundaryconditioninrandomporousmaterials.Firstly,themicroscopicconfigurationforthestructurewithrandomdistributionisbrieflycharacterized.Secondly,theSSOTSformulaeforcomputingtheheattransferproblemarederivedsuccessivelybymeansoftheconstructionwayforeachcell.Then,thestatisticalpredictionalgorithmbasedontheproposedtwo-scalemodelisdescribedindetail.Finally,somenumericalexperimentsareproposed,whichshowthattheSSOTSmethoddevelopedinthispaperiseffectiveforpredictingtheheattransferperformanceofporousmaterialsanddemonstratingitssignificantapplicationsinactualengineeringcomputation.
简介:AlthoughtheimpactofroadtransportonurbanairqualityhasachievedahighprofileinChina,stillgreaterattentionisrequiredasithasnotyetbeenconsideredfullyeveninrelationtotheroadnetworklinkingcitiesandurbanareas.Strategicenvironmentalassessment(SEA)isasystematicandcomprehensiveprocessforevaluatingtheenvironmentalimpactsofapolicy,planorprograminpubliclyaccountabledecision-making.AirpollutionhasbeenrecognizedasasignificantissueinmosttransportSEApractices.TheStrategicEnvironmentalAssessmentoftheHubeiRoadNetworkPlan(2002-2020)(HRNP)wasintroducedasoneoftheWorldBank'spilotSEAprojects.Aneffectiveframeworkwasdevelopedtoinvestigatethefunctionalrelationshipbetweentheroadnetworkanditspotentialairpollutantemissions.Inthisstudy,twoindicatorswereidentified:emissionintensity/inventoryofpollutantsandthespatialdistributionofthemostpollutedareas.Becausestrategicactionsareinherentlynebulousanddataqualityisoftendisappointing,threealternativescenarioswereemployedtoaddressuncertaintiesanddata/scaleissues.Calculationsweremadeusingemissionmodelsandresultswereanalyzedwiththehelpofstatisticaltoolsandthegeographicinformationsystem(GIS).TheresultsfromtheprojectimplementationandthefeedbackfromtheWorldBankhavebothshownthattheproposedframeworkiseffectiveinthetransportSEAprocess.
简介:High-temperaturePhaseChangeMaterial(PCM)isusedasathermalstoragemediumofaheat-pipereceiverinanadvancedsolardynamicsystem.Withbothvoidcavityandnaturalconvectionconsidered,thermalperformanceoftheheat-pipereceiverisnumericallyanalyzedundergravity.TheresultsindicatethatthePCMcontainedintheintegratedheatpipeperformsanaveragingfunctionofheatloadings.Thethermalperformanceoftheheat-pipereceiverisstableandreliable.Whenaheatingcycleisstable,thetemperaturefluctuationsbothonheat-pipewallandinPCMcanisterremainlessthan13Kthroughoutasunlightandeclipsecycle.TheutilityofPCMisessentiallyimproved.ThemaximummeltingratioofPCMis92%.Undergravity,PCMmeltsmorequicklywiththeeffectofnaturalconvection.Naturalconvectionacceleratestheprocessofphasechanges.Numericalresultsarecomparedwiththeexperimentalresultsconcerned.Theaccuracyofnumericalmodelundergravityisverified.TheexperimentforthePCMcanisteronthegroundcanbewellpreparedwithournumericalsimulation.
简介:Opticalcouplingbehaviorandassociatedeffectsintwo-dimensionalimplant-definedcoherentlycoupledverticalcavitysurface-emittinglaser(VCSEL)arraysarestudiedviabothexperimentsandtheoreticalcalculations.Experimentsshowthatopticalcouplingbetweenarrayelementscanenhancethearray’soutputpower.Additionally,opticalcouplingvialeakyopticalfieldscanprovideextraopticalgainforthearrayelements,whichcanthenreducethethresholdsoftheseelements.Elementscanevenbepumpedwithoutcurrentinjectiontoemitlightbyreceivingastrongleakyopticalfieldfromotherarrayelements.Opticalcouplingcanalsocauseunusualphenomena:thecentralelementsinlarge-areacoherentlycoupledVCSELarraysthatlasepriortotheouterelementswhenthearraysarebiased,ortheaverageinjectioncurrentrequiredforeachelementtolase,whichismuchlowerthanthethresholdforasingleVCSEL.Theoreticalcalculationsareperformedtoexplaintheexperimentalresults.