简介:Wepresentnumericalcalculationoftheimpactofelectron-electroninteractiononthebehaviorofdensityofstatesandopticalpropertiesofBeO,SiCandBoron-Nitridenanotubesandsheets.Hubbardmodelhamiltonianisappliedtodescribethedynamicsofelectronsonthelatticestructureofthesescompounds.TheexcitationspectrumofthesysteminthepresenceoflocalelectronicinteractionshasbeenfoundusingmeanSeldapproach.WefindthebandgapwidthinbothopticalabsorptionanddensityofstatesreduceswithlocalHubbardelectronicinteractionparameter.Theabsorptionspectraexhibitstheremarkablepeaks,mainlyowingtothedivergencebehaviorofdensityofstatesandexcitoniceffects.AlsowecompareopticalabsorptionfrequencybehaviorofBeO,SiCandBoron-Nitridenanotubeswitheachother.FurthermoreweinvestigatetheopticalpropertiesofBeOandSiCsheets.Anovelfeatureofopticalconductivityofthesestructuresisthedecreaseoffrequencygapintheopticalspectrumduetoelectronicinteraction.
简介:Athoroughunderstandingonthemechanicalpropertiesofcarbonnanotube(CNT)isessentialinextendingtheadvancedapplicationsofCNTbasedsystems.However,conductingexperimentstoestimatemechanicalpropertiesatthisscaleisextremelychallenging.Therefore,developmentofmechanisticmodelstoestimatethemechanicalpropertiesofCNTsalongwiththeintegrationofexistingcontinuummechanicsconceptsiscriticallyimportant.ThispaperpresentsacomprehensivemoleculardynamicssimulationstudyonthesizedependencyandpotentialfunctioninfluenceofmechanicalpropertiesofCNT.Commonlyusedreactivebondorder(REBO)andadaptiveintermolecularreactivebondorder(AIREBO)potentialfunctionswereconsideredinthisregard.Young'smodulusandshearmodulusofCNTsarederivedbyintegratingclassicalcontinuummechanicsconceptswithmoleculardynamicssimulations.TheresultsindicatethatthepotentialfunctionhasasignificantinfluenceontheestimatedmechanicalpropertiesofCNTs,andtheinfluenceofpotentialfieldismuchhigherwhenstudyingthetorsionalbehaviourofCNTsthanthetensilebehaviour.
简介:Inthisstudy,one-dimensionaltitaniananotubes(TNTs)weresynthesizedusingacombinedprocessofchemicalandhydrothermaltreatments,andtheiractivitiesforthephotocatalyticreactionsofselectedgaseouspollutantsatsub-ppmlevelsweredetermined.Additionally,thepropertiesoftheTNTswereexaminedusingselectedspectroscopicmethods.TheannealedTNTsshowedhigherphotocatalyticactivitiesforthefourtargetcompoundsthandidtheunannealedTNTs.Forallthetargetcompoundsexceptbenzene,theeffectoftheannealingtemperatureonthedegradationefficiencywasdifficulttodeterminebecausealldegradationefficiencieswereveryhigh.However,forbenzene,whichdecomposedwithalowefficiency,thedegradationactivitiesoftheTNTsincreasedasthetreatmenttemperaturewasincreasedfrom250to300℃,whiletheydecreasedslightlywhenthetemperaturewasincreasedfrom300to400℃.ThesefindingsconfirmthepresenceofanoptimalannealingtemperatureforthesynthesisofTNTs.Moreover,theaveragedegradationextentsforbenzene,toluene,ethylbenzene,ando-xylenedecreasedfrom92%,96%,99%,and98%to77%,86%,92%,and94%,respectively,astheairstreamflowrateincreasedwithintherangeof1-4L/min.Theaveragedegradationextentsdecreasedfrom12%,75%,87%,and88%to3%,29%,46%,and51%,respectively,astheinputconcentrationincreasedfrom0.4to1.9ppm.Overall,thesefindingssuggestthatone-dimensionalTNTscanbeeffectivelyutilizedforthedegradationofgaseouspollutantsunderoptimaloperationalconditions.
简介:Li4Ti5O12(LTO)/carbonnanotubes(CNTs)compositematerialissynthesizedbasedonasolid-statemethodbysand-milling,spray-dryingandcalciningat8508CunderN2flow.TheLTO/CNTssampleswith1wt%and3wt%weightratioofCNTsadditionandthepristineLTOsampleareprepared.TherateperformanceandthethermalstabilityofthesesamplesareinvestigatedbasedonLiMn2O4(LMO)/LTOfull-cell.TheresultsshowthattheweightratioofCNTsadditionhasdistincteffectonLTOperformances.ThecompositematerialsofLTOcompositedCNTshavebetterperformanceathigh-rateduetotheintercalationenhancementbyconductivenetworkofCNTs.Atsecond,theoverchargingtemperatureresponseofthecell’ssurfacewith1wt%CNTsadditionisthelowest.Theparticlesizedistributionismeasuredandthemostuniformparticlesareobtainedwith1wt%CNTsaddition.ThistrendcouldexplainthatthemediumquantityofCNTsisoptimaltoimprovetheheatandmasstransferandpreventtheproblemsofcrystallitegrowinginterferenceandaggregationduringthecalcinationprocess.