简介:SupposethatDisaboundeddomainwithapiecewiseC^1smoothboundaryinC^n.Letψ∈C^1+α(δD).ByusingtheHadamardprincipalvalueofthehigherordersingularintegralandsolidanglecoefficientmethodofpointsontheboundary,wegivethePlemeljformulaofthehigherordersingularintegralwiththeBoehner-Martinellikernel,whichhasintegraldensityψ.Moreover,bymeansofthePlemeljformulaandmethodsofcomplexpartialdifferentialequations,wediscussthecorrespondingCauehyboundaryvalueproblemwiththeBoehner-Martinellikernelonaclosedpiecewisesmoothmanifoldandobtainitsuniquebranchcomplexharmonicsolution.
简介:Basedonthethermodynamictheory,anorthotropicdamageconstitutivemodelwasdevelopedtodescribethenonlinearmechanicalbehaviorofC/SiCcomposites.Thediferentnonlinearkinematicandisotropichardeningfunctionswereadoptedtodescribeaccuratelythedamageevolutionprocesses.Thedamagevariablesweredefinedwiththedamagedmodulusandtheinitialundamagedmodulusonenergyequivalenceprinciple.Theinitialorthotropyanddamagecouplingwerepresentedinthedamageyieldfunction.Tensileandin-planeshearloadingandunloadingtestswereperformed,andagoodagreementbetweenthemodelandtheexperimentalresultswasachieved.
简介:TheeffectofacidcomponentincludingvariousconventionalacidsandtungsticcompoundsonglucosehydrogenationoveraseriesofbinarycatalystsystemcontainingRu/Ccatalystwasinvestigated.TheresultsshowedthatHCl,H2SO4,H3BO3,H3PO4,andHNO3hadnegligibleeffect,whileallthetungsticcompoundsimposedinhibitingeffectsonthehydrogenationofglucoseoverRu/Ccatalyst,andthesuppressingeffectfollowedtheorderofH2WO4>HPW>WO3>AMT>HSiW.Thisorderisthesameastheorderofethyleneglycol(EG)yieldsintheone-potconversionofglucosetoEG,suggestingtheimportantroleofcompetitionbetweenglucosehydrogenationandretro-aldolcondensationincontrollingtheselectivityofEG.
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简介:Thedevelopmentofthehydrogenelectrodeisvitalfortheapplicationofalkalinepolymerelectrolytefuelcells(APEFCs).Inthisstudy,aseriesofNi(OH)2decoratedNi/Ccatalysts(Ni(OH)2-Ni/C)werepreparedbyathree-stepelectrochemicaltreatmentofNi/C.TheexistenceofNi(OH)2wasdemonstratedbyX-rayphotoelectronspectroscopy(XPS),andthesurfacemolarratioofNi(OH)2/Niofthesampleswasestimatedviaanelectrochemicalmethod.TheHORcatalyticactivityofthecatalystswasevaluatedbyarotationdiskelectrode(RDE)method,anda'volcanoplot'wasestablishedbetweentheHORexchangecurrent(j0)andthesurfacemolarratioofNi(OH)2/Ni.Ontopofthe'volcano',thesurfacemolarratioofNi(OH)2/Niis1.1:1,thej0ofwhichwas6.8timesofthatofNi/C.ThestabilityofthesamplestowardHORwasevaluatedtobegood.OurstudyaddedasystematicexperimentalevidencetotheHORresearch,showingthattheHORcatalyticactivityofNicanbedeliberatelycontrolledviadecorationofNi(OH)2,whichmayhelpunderstandingtheHORmechanismonNi.
简介:Twocompactandintense2.45GHzpermanentprotonsourcesandtheircorrespondinglowenergybeamtransport(LEBT)systemsweredevelopedsuccessfullyforChinaAcceleratorDrivenSub-criticalsystem(C-ADS)in2014,oneofwhichwasbuiltatIMP,LanzhouandtheotheratIHEP,Beijing.Bothprotonsourcescandeliverstable10mA/35keVprotonbeamsatCWmodetotheentrancesofthedownstreamRFQs.AsshowninFig.1,thebeamsextractedbya3-electrodeextractionsystemaretransportedbytheLEBTsystem,whichiscomposedof2identicalsolenoids,andintothe3.2or2.1MeVradio-frequencyquadrupole(RFQ).Inordertoensuresuperconductingcavitiescommissioningandprotection,anelectrostatic-chopperhasbeendesignedandinstalledintheLEBTlinethatcanchopthecwbeamFig.2Totalhydrogenionbeamcurrentversusinputpower.intoapulsedone.Theachievedfall/risetimeofthechopperislessthan20ns.
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简介:CarbonsupportedPt(Pt/C)electrocatalystswerepreparedwithglucoseasprotectionagentandNaBH4asreductant.ThePtnanoparticlesdepositedoncarbonsupportpresentedreducedsizeandwelldispersityattributedtotheprotectioneffectofglucose.GlucoseabsorbedontheparticlesurfacewasreadilyremovedbywaterwashingwithoutleadingtoagglomerationofthePtnanoparticles.Theas-preparedPt/Celectrocatalystsshowedimprovedmassactivityformethanolelectrooxidationcomparedtothecatalystpreparedwithoutglucoseprotection.TheimprovedperformanceisattributedtothelargerelectrochemicalactivesurfaceareathusincreasedactivesitesonthePt/Celctrocatalystspreparedundertheprotectionofglucose.