简介:Inthisarticlewedefineasurfacefiniteelementmethod(SFEM)forthenumericalsolutionofparabolicpartialdifferentialequationsonhypersurfacesFinR~(n+1).ThekeyideaisbasedontheapproximationofFΓbyapolyhedralsurfaceΓ_hconsistingofaunionofsimplices(trianglesforn=2,intervalsforn=1)withverticesonF.AfiniteelementspaceoffunctionsisthendefinedbytakingthecontinuousfunctionsonΓ_hwhicharelinearaffineoneachsimplexofthepolygonalsurface.WeusesurfacegradientstodefineweakformsofellipticoperatorsandnaturallygenerateweakformulationsofellipticandparabolicequationsonΓ.Ourfiniteelementmethodisappliedtoweakformsoftheequations.Thecomputationofthemassandelementstiffnessmatricesaresimpleandstraightforward.Wegiveanexampleoferrorboundsinthecaseofsemi-discretizationinspaceforafourthorderlinearproblem.Numericalexperimentsaredescribedforseverallinearandnonlinearpartialdifferentialequations.Inparticularthepowerofthemethodisdemonstratedbyemployingit,tosolvehighlynonlinearsecondandfourthorderproblemssuchassurfaceAllen-CahnandCahn-Hilliardequationsandsurfacelevelsetequationsforgeodesicmeancuryatureflow.
简介:Aminopropyl,ethylenediamine,ethenylandglycidoxygroupsfunctionalizednanoparticles,withaveragediametersrangingfrom4to6nmandcontaining1.17mmolofgroups/g,arereadilyobtainedfromnanodiamondsmodifiedwithsilanecouplingagent.Forthestudyofthesenanoparticles,TEM,IRS,XPS,andTGanalysismethodshavebeenused.
简介:Thetimeevolutionofoxygenplasmatreatedpolystyrene(PS)surfaceswasinvestigateduponstoringthemintheairundercontrolledhumidityconditions.Themethodsofwatercontactangle,X-rayphotoelectronspectroscopy(XPS),sumfrequencygeneration(SFG)vibrationalspectroscopy,andatomicforcemicroscopy(AFM)wereusedtoinferthesurfacepropertiesandstructure.ChemicalgroupscontainingoxygenwereformedonthePSsurfacewiththeplasmatreatment,demonstratedbywatercontactangleandXPS.Thesurfacepolaritydecayedmarkedlyontime,asassessedbysteadyincreaseinthewatercontactangleasafunctionofstoragetime,fromzerotoaround60°.Theobserveddecayisinterpretedasarisingfromsurfacerearrangementprocessestoburyingpolargroupsawayfromtheuppermostlayerofthesurfaces,whichisincontactwithair.Ontheotherhand,XPSresultsshowthatthechemicalcompositioninthefirst3nmsurfacelayerisunaffectedbythesurfaceaging,andthedepthprofileofoxygenisessentiallythesamewithtime.ApossiblechangeofPSsurfaceroughnesswasexaminedbyAFM,anditshowedthattheincreaseofwatercontactangleduringsurfaceagingcouldnotbeattributedtosurfaceroughness.Thus,itisconcludedthatsurfaceagingisattributabletosurfacereorganizationandthemotionofoxygencontaininggroupsisconfinedwithintheXPSprobingdepth.SFGspectroscopy,whichisintrinsicallyinterface-specific,wasusedtodetectthechemicalstructureofPSsurfaceatthemolecularlevelaftervariousagingtimes.Theresultsareinterpretedasfollows.DuringtheagingoftheplasmatreatedPSsurfaces,theoxygencontaininggroupsundergoreorientationprocessestowardthepolymerbulkand/orparalleltothesurface,whiletheCH2moietystandsuponthePSsurface.Ourresultsindicatethatthesurfaceconfigurationchangesdonotrequirelargelengthscalesegmentalmotionsormigrationofmacromolecules.Motionsthatareresponsibleforsurfaceconfigurationchangescoul
简介:Thisreviewfocusedontherecentreportsrelatedtothefunction,characterizationandmodificationofoxygen-containingsurfacegroupsofactivatedcarbon(AC).TheOxygen-containingsurfacegroupswerebrieflydescribed,andthemostfrequentlyusedtechniquesforcharacterizationoftheoxygen-containingsurfacegroupsonACswerealsobrieflystated.Adetaileddiscussionoftheeffectsoftheoxygen-containingsurfacegroupsontheadsorptivecapacityofACwasgiven.Therecentprogressesinmodificationoftheoxygen-containingsurfacegroupsofACwerealsoreviewed.
简介:Ahybridmodeofone-andtwo-surfacemultipactoronthegrooveddielectricsurfaceisstudiedindetailusingbothananalyticalapproachandtwo-dimensionalparticle-in-cell(2DPIC)simulations.WhenthegroovewidthL
简介:Theplasmonicnanogapantennaisanefficientradiatingorreceivingopticaldevice.Theresonancebehaviorofopticalantennasiscommonlyattributedtotheexcitationofalocalizedsurfaceplasmonresonance(LSPR),whichcanbetheoreticallydefinedasthequasi-normalmode(QNM).ToclarifythephysicaloriginoftheLSPR,webuildupananalyticalmodeloftheLSPRbyconsideringamultiplescatteringprocessofpropagativesurfaceplasmonpolaritons(SPPs)ontheantennaarms.ThemodelcancomprehensivelyreproducethecomplexeigenfrequencyandthefielddistributionofQNMsoftheantenna,unveilingthattheLSPRarisesfromaFabry–PerotresonanceofSPPs.Byfurtherapplyingthecomplexpoleexpansiontheoremofmeromorphicfunctions,thefieldoftheantennaunderilluminationbyanearbydipoleemittercanbeanalyticallyexpandedwithQNMs,whichwellpredictsthefrequencyresponseoftheenhancementfactorofradiation.ThepresentmodelestablishesexplicitrelationsbetweentheconceptsoftheLSPRandthepropagativeSPPandintegratestheadvantagesoftheFabry–PerotandQNMformalismsofnanogapantennas.
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简介:PolysiliconMicroelectromechanicalsystems(MEMS)arethesubjectofintensiveresearches.SurfacechemistryandtopographyofaMEMSteststructurefabricatedatSandiaNationalLaboratory,USA,werestudiedbymeansofscanningelectronmicroscopy(SEM),X-rayphotoelectronspectroscopy(XPS)andatomicforcemicroscopy(AFM).XPSC()andSi2,spectrafromthepolysilieoncomponents,siliconnitridesubstrateandareferencesiliconwaferwerecompared.Theresultsconfirmthepresenceofaself-assembledmonolayer(SAM)ontheMEMSsurface.Anisland-likemorphologywasfoundonbothpolysiliconandsiliconnitridesurfacesoftheMEMS.Theislandstaketheformofcaps,beingupto0.5μmindiameterand20nminheight.Itisconcludedthattheco-existenceofcolumnargrowthandequiaxedgrowthduringthelowpressurechemicalvapordeposition(LPCVD)oftheselayersleadstotheobservedmorphologyandtheislandsarecapstothecolumnarstructures.
简介:Surfaceeffectsonthepersistencelengthofquasi-one-dimensionalnanomaterialsareinvestigatedbyusingthetheoryofsurfaceelasticityandthecore–shellmodelofnanobeams.Asimpleandunifiedexpressionisprovidedtodeterminethepersistencelengthofnanowiresandnanotubeswithanyregularpolygonalcross-sections.Itisdemonstratedthatsurfaceeffectshaveadistinctinfluenceonthepersistencelengthwhenthecharacteristicsizesofmaterialsshrinktonanometers.Thisworkishelpfulnotonlyforunderstandingthesize-dependentbehaviorofnanomaterialsbutalsoforthedesignofdevicesbasedonnanotubesornanowires.
简介:为了在大气的踪迹部件,包括煤气阶段的化学过程的acoupled盒子模型,热力学的平衡处理的喷雾器,和异构的化学药品上探索异构的化学过程的可能的影响,在灰尘的表面上处理,黑碳(BC)和海盐被设置在喷雾器表面上模仿异构的化学的效果,并且分析影响异构的过程的主要因素。结果显示在空气的喷雾器表面上的异构的化学过程将影响踪迹气体例如的集中H2O2,HO2,O3,NO2,NO3,HNO3和SO2,和象SO42那样的喷雾器?,NO3吗?并且NH4+。敏感测试建议异构的进程的影响的大小强烈取决于喷雾器集中和系数在框模型使用了的表面举起。然而,异构的化学过程上的温度的影响是更加少些。HNO3的renoxification将影响象氮氧化物和臭氧那样的对流层的部件。
简介:TheeffectsofσandΦmesonsonthesurfaceredshiftofaneutronstarhavebeeninvestigatedwithintheframeworkofrelativisticmeanfieldtheoryforthebaryonoctet{n,p,Λ,Σ,Σ0,Σ+,Ξ,Ξ0}system.ItisfoundthatcomparedwiththosewithoutconsideringthecontributionsofσandΦmesons,thesurfaceredshiftdecreasesandthatcorrespondingtothemaximumvalueofthemassalsodecreasesfrom0.2540to0.2236,aboutby12%.Meanwhile,itisalsofoundthatincludingσandΦmesons,theM/Randthatcorrespondingtothemaximummassdecrease.
简介:Solution-drivenmeshadaptationisbecomingquitepopularforspatialerrorcontrolinthenumericalsimulationofcomplexcomputationalphysicsapplications,suchasclimatemodeling.Typically,spatialadaptationisachievedbyelementsubdivision(hadaptation)withaprimarygoalofresolvingthelocallengthscalesofinterest.Asec-ond,less-popularmethodofspatialadaptivityiscalled'meshmotion'(radaptation);thesmoothrepositioningofmeshnodepointsaimedatresizingexistingelementstocapturethelocallengthscales.Thispaperproposesanadaptationmethodbasedonacombinationofbothelementsubdivisionandnodepointrepositioning(rhadaptation).Bycombiningthesetwomethodsusingthenotionofamobilityfunction,theproposedapproachseekstoincreasetheflexibilityandextensibilityofmeshmotionalgorithmswhileprovidingasomewhatsmoothertransitionbetweenrefinedregionsthanispro-ducedbyelementsubdivisionalone.Further,inanattempttosupporttherequirementsofaverygeneralclassofclimatesimulationapplications,theproposedmethodisde-signedtoaccommodateunstructured,polygonalmeshtopologiesinadditiontothemostpopularmeshtypes.
简介:Inordertoestimatetheerosionratesofsomeplasmafacingcomponentmaterials,thesputteringyieldsofMo,Wanddeuterium-saturatedLibombardedbyfusionchargedparticlesarecalculatedbyapplicationofnewsputteringphysicsdescriptionmethodsbasedonthebipartitionmodelofiontransporttheory.ThecomparisonswithMontecarlocalculationandexperimentalresultsaremade.Thesedatamightbeusefultoestimatethelifetimeofplasmafacingcomponentsandtoanalysetheimpuritylevelincoreplasmaoffusionreactors.
简介:Thispaperdemonstratesanewprocessofthephotolithographytechnology,usedtofabricatesimplyfinepatterns,byemployingsurfaceplasmoncharacter.Thesub-wavelengthperiodicsilicastructureswithuniformsilverfilmareusedastheexposuremask.Accordingtothetraditionalsemiconductorprocess,thegratingstructuresarefabricatedatexposingwavelengthof436nm.Atthesametime,itprovidesadditionalandquantitativesupportofthistechniquebasedonthefinite-differencetime-domainmethod.Theresultsoftheresearchshowthatsurfaceplasmoncharacteristicsofmetalscanbeusedtoincreasetheopticalfieldenergydistributiondifferencesthroughthesilicastructureswithsilverfilm,whichdirectlyimpactontheexposureoffollowingphotosensitivelayerindifferentregions.
简介:Thispaperreportsonalaboratory-basedstudycarriedouttoevaluatetheeffectivenessofsurfacetreatmentsonthedurabilityofconcreteandsuggestsanumberofdifferentevaluationmethodologiesforassessingtheperformanceofvarioussurfacetreatments.Durabilityofuntreatedandtreatedconcretespecimenswasevaluatedbymeasuringchloridediffusion,chargepassingcapacity,airpermeabilityandwaterabsorption.Atotalofsixconcretesurfacetreatmentswereselectedtorepresentdifferentgenerictypes,includingcoating,penetrantandmixed-usetreatments.Resultsshowthattheconcretespecimenswithacoatingprocedurehaveabetterlong-termperformanceandeffectivenessthanthespecimenswiththepenetranttreatments.Thisworkalsoindicatesthatthewettinganddryingcyclestestcanbeusedtoassesstheweatherabilityofthesurfacetreatments.TheASTMC1202andtheAutoclamairpermeabilitytestcanbeusedtoevaluatetheeffectivenessofsurfacetreatmentsquantitatively.Furtherworkisneeded,however,toassessthelongevityofthevarioussurfacetreatments.
简介:Inthispaper,anewtypeofresonantBrewsterfilters(RBF)withsurfacereliefstructureforthemultiplechannelsisfirstpresentedbyusingtherigorouscoupled-waveanalysisandtheS-matrixmethod.Bytuningthedepthofhomogeneouslayerwhichisunderthesurfacereliefstructure,themultiplechannelsphenomenonisobtained.Longrange,extremelylowsidebandsandmultiplechannelsarefoundwhentheRBFwithsurfacereliefstructureisilluminatedwithTransverseMagneticincidentpolarizationlightneartheBrewsteranglecalculatedwiththeeffectivemediatheoryofsubwavelengthgrating.Moreover,thewavelengthsofRBFwithsurfacereliefstructurecanbeeasilyshiftedbychangingthedepthofhomogeneouslayerwhileitsopticalpropertiessuchaslowsidebandreflectionandnarrowbandarenotspoiledwhenthedepthischanged.Furthermore,thevariationofthegratingthicknessdoesnoteffectivelychangetheresonantwavelengthofRBF,buthavearemarkableeffectonitslinewidth,whichisveryusefulfordesigningsuchfilterswithdifferentlinewidthsatdesiredwavelength.