简介：Todealwiththestaircaseapproximationprobleminthestandardfinite-differencetime-domain(FDTD)simulation,thetwo-dimensionalboundaryconditionequations(BCE)methodisproposedinthispaper.IntheBCEmethod,thestandardFDTDalgorithmcanbeusedasusual,andthecurvedsurfaceistreatedbyaddingtheboundaryconditionequations.Thus,whilemaintainingthesimplicityandcomputationalefficiencyofthestandardFDTDalgorithm,theBCEmethodcansolvethestaircaseapproximationproblem.TheBCEmethodisvalidatedbyanalyzingnearfieldandfarfieldscatteringpropertiesofthePECanddielectriccylinders.TheresultsshowthattheBCEmethodcanmaintainasecond-orderaccuracybyeliminatingthestaircaseapproximationerrors.Moreover,theresultsoftheBCEmethodshowgoodaccuracyforcylinderscatteringcaseswithdifferentpermittivities.

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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：Inthisstudy,weinvestigatetheinfluenceofdopingonthechargetransferanddevicecharacteristicsparametersinthebulkheterojunctionsolarcellsbasedonpoly(3-hexylthiophene)(P3HT)andamethanofuUerenederivative(PCBM).Organicsemiconductorsarealsoknowntobenotpureandtheyhavedefectsandimpurities,someofthemarebeingchargedandactasp-typeorn-typedopants.Calculationsofthesolarcellcharacteristicsparametersversusthep-dopinglevelhavebeendoneatthreedifferentn-dopings(N_d)thatconsistof5×10~(17)cm~(-3),10~(18)cm~(-3),and5×10~(18)cm~(-3).Weperformtheanalysisofthedopingconcentrationthroughthedrift-diffusionmodel,andcalculatethecurrentandvoltagedopingdependency.Wefindthatatthreedifferentn-dopantlevels,optimump-typedopingisaboutN_p=6×10~(18)cm~(-3).Simulationresultshaveshownthatbyincreasingdopinglevel,V_(oc)monotonicallyincreasesbydoping.CellefficiencyreachesitsmaximumatsomewhathigherdopingasFFhasitspeakatN_p=3×10~(18)cm~(-3).Moreover,thispaperdemonstratesthattheoptimumvalueforthep-dopingisaboutN_p=6×10~(18)cm~(-3)andoptimumvalueforn-dopantisN_d=10~(18)cm~(-3),respectively.Thesimulatedresultsconfirmthatdopingconsiderablyaffectstheperformanceoforganicsolarcells.

简介：AnewSnO_2-Fe_2O_3/SWCNTs(single-walledcarbonnanotubes)ternarynanocompositewasfirstsynthesizedbyafacilehydrothermalapproach.SnO_2andFe_2O_3nanoparticles(NPs)werehomogeneouslylocatedonthesurfaceofSWCNTs,asconfirmedbyX-raydiffraction(XRD),transmissionelectronmicroscope(TEM)andenergydispersiveX-rayspectroscopy(EDX).Duetothesynergisticeffectofdifferentcomponents,theassynthesizedSnO_2-Fe_2O_3/SWCNTscompositeasananodematerialforlithium-ionbatteriesexhibitedexcellentelectrochemicalperformancewithahighcapacityof692mAh·g~(-1)whichcouldbemaintainedafter50cyclesat200mA·g~(-1).Evenatahighrateof2000mA·g~(-1),thecapacitywasstillremainedat656mAh·g~(-1).

简介：ThisArticlepresentsathreedimensionalnumericalmodelinvestigatingthermalperformanceandhydrodynamicsfeaturesoftheconfinedslotjetimpingementusingslurryofNanoEncapsulatedPhaseChangeMaterial(NEPCM)asacoolant.Theslurryiscomposedofwaterasabasefluidandn-octadecaneNEPCMparticleswithmeandiameterof100nmsuspendedinit.AsinglephasefluidapproachisemployedtomodeltheNEPCMslurry.ThethermophysicalpropertiesoftheNEPCMslurryarecomputedusingmodernapproachesbeingproposedrecentlyandgoverningequationsaresolvedwithacommercialFiniteVolumebasedcode.TheeffectsofjetReynoldsnumbervaryingfrom100to600andparticlevolumefractionrangingfrom0%to28%areconsidered.ThecomputedresultsarevalidatedbycomparingNusseltnumbervaluesatstagnationpointwiththepreviouslypublishedresultswithwaterasworkingfluid.ItwasfoundthataddingNEPCMtothebasefluidresultswithconsiderableamountofheattransferenhancement.ThehighestvaluesofheattransfercoefficientsareobservedatH/W=4andC_m=0.28.However,duetothehigherviscosityofslurrycomparedwiththebasefluid,theslurrycanproducedrasticincreaseinpressuredropofthesystemthatincreaseswithNEPCMparticleloadingandjetReynoldsnumber.

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简介：Inthepresentwork,aninterconnectedsandwichcarbon/Si-SiO2/carbonnanospherescompositewaspreparedbytemplatemethodandcarbonthermalvapordeposition（TVD）.ThecarbonconductivelayercannotonlyefficientlyimprovetheelectronicconductivityofSi-basedanode,butalsoplayakeyroleinalleviatingthenegativeeffectfromhugevolumeexpansionoverdischarge/chargeofSi-basedanode.Theresultingmaterialdeliveredareversiblecapacityof1094mAh/g,andexhibitedexcellentcyclingstability.Itkeptareversiblecapacityof1050mAh/gover200cycleswithacapacityretentionof96%.

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简介：Inthisstudy,nano-polyanlineandmanganeseoxidenanometertubularcomposites(nano-PANI@MnO2)werepreparedbyasurfaceinitiatedpolymerizationmethodandusedaselectrochemicalcapacitorelectrodematerials;andtheeffectofanilineamountonthemicrostructureandelectrochemicalperformancewasinvestigated.Themicrostructuresandsurfacemorphologiesofnano-PANI@MnO2werecharacterizedbyX-raydiffraction,scanningelectronmicroscopyandfouriertransformationinfraredspectroscope.Theelectrochemicalperformanceofthesecompositematerialswasperformedwithcyclicvoltammetry,charge–dischargetestandelectrochemicalimpedancespectroscopy,respectively.TheresultsdemonstratethatthefeedratioofanilinetoMnO2playedaveryimportantroleinconstructingthehierarchicallynano-structure,whichwould,hence,determinetheelectrochemicalperformanceofthematerials.UsingthetemplateassistedstrategyandcontrollingthefeedratioofanilinetoMnO2,thenanometertubularstructureofnanoPANI@MnO2wasobtained.Amaximumspecificcapacitanceof386F/gwasachievedinaqueous1mol/LNaNO3electrolytewiththepotentialrangefrom0to0.6V(vs.SCE).

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简介：LiMn2O4andLiNixAlyMn2-x-yO4（x=0.50;y=0.05-0.50）powdershavebeensynthesizedviafacilesolgelmethodusingBehenicacidasactivecheiatingagent.Thesynthesizedsamplesaresubjectedtophysicalcharacterizationssuchasthermogravimetricanalysis（TG/DTA）,X-raydiffraction（XRD）,Fouriertransforminfraredspectroscopy（FT-IR）,field-emissionscanningelectronmicroscopy（FESEM）,transmissionelectronmicroscopy（TEM）andelectrochemicalstudiesviz.,galvanostaticcyclingproperties,electrochemicalimpedancespectroscopy（EIS）anddifferentialcapacitycurves（dQ/dE）.FingerprintXRDpatternsofLiMn2O4andLiNixAlyMn2-x-yO4fortifythehighdegreeofcrystallinitywithbetterphasepurity.FESEMimagesoftheundopedpristinespinelillustrateuniformsphericalgrainssurfacemorphologywithanaverageparticlesizeof0.5μmwhileNidopedparticlesdepictthesphericalgrainsgrowth（50nm）withice-cubesurfacemorphology.TEMimagesofthespinelLiMn2O4showstheuniformsphericalmorphologywithparticlesizeof（100nm）whilelowlevelofAl-dopingspinel（LiNio.5Alo.05Mn1.45O4）displayingcloudyparticleswithagglomeratedparticlesof（50nm）.TheLiMn2O4samplescalcinedat850℃deliverthedischargecapacityof130mAh/ginthefirstcyclecorrespondsto94%coiumbicefficiencywithcapacityfadeof1.5mAh/g/cycleovertheinvestigated10cycles.Amongallfourdopantcompositionsinvestigated,LiNi0.5Al0.05Mn1.45O4deliversthemaximumdischargecapacityof126mAh/gduringthefirstcycleandshowsthestablecyclingperformancewithlowcapacityfadeof1mAh/g/cycle（capacityretentionof92%）overtheinvestigated10cycles.ElectrochemicalimpedancestudiesofspinelLiMn2O4andLiNi0.5Al0.05Mn1.45O4depictthehighandlowrealpolarizationof1562and1100Ω.

简介：Throughournewly-developed'chemicalvapordepositionintegratedprocess(CVD-IP)'usingcarbondioxide(CO2)astherawmaterialandonlycarbonsourceintroduced,CO2couldbecatalyticallyactivatedandconvertedtoanewsolid-formproduct,i.e.,carbonnanotubes(CO2-derived)ataquitehighyield(thesingle-passcarbonyieldinthesolid-formcarbon-productproducedfromCO2catalyticcaptureandconversionwasmorethan30%atasingle-passcarbon-base).Forcomparison,whenonlypurecarbondioxidewasintroducedusingtheconventionalCVDmethodwithoutintegratedprocess,nosolid-formcarbon-materialproductcouldbeformed.IntheadditionofsaturatedsteamatroomtemperatureinthefeedforCVD,thereweremuchmoreend-openingcarbonnano-tubesproduced,ataslightlyhighercarbonyield.Theseinspiringworksopenedaremarkableandalternativenewapproachforcarbondioxidecatalyticcapturetosolid-formproduct,comparingwiththatofCO2sequestration(CCS)orCO2mineralization(solidification),etc.Asaresult,therewasmuchlessbodyvolumeandalmostnogreenhouseeffectforthissolid-formcarbon-materialthanthoseofprimitivecarbondioxide.