简介:IntercalationcompoundFePS3(CoCp2)0.40(CoCp2=cobaltocene)wassynthesized,andthecrystalstructureandmagneticpropertieswerestudiedbyx-raydiffraction,magneticsusceptibilitymeasurement,andMSssbauerspectroscopy.Thecrystalstructurewasindexedtomonoclinicunitcellwitha=5.996^。A,b=10.106^。A,c=12.511^。A,β=105.916°,andabout5.6^。Aexpansionatthec-directioncomparedtopureFePS3.TheMSssbauerspectraindicatethattherearethreekindsofdivalentionswithhighspinstateintheintercalationcompound,whichimplieschargetransferfromguesttotheFe-Se^*ganti-bondingorbitsofthehostlattice.Nocationicvacanciesareformedintheintercalationcompound.Theferromagnetismatlowtemperatureoriginatesfromthespincantingofdivalentions.
简介:ThegatedielectricthicknessdecreasesdramaticallywiththecontinuousscalingofMOSdevices,whichhasseriousconsequencesontheleakagecurrentandthepowerconsumptionoftheSiO2-basedMOSdevices.Hafniumdioxide(HfO2),asakindofhigh-kmaterial,arerecognizedasalternativestoSiO2forfutureadvancedgatedevicesandspaceapplications[1].Radiation-inducedeffectsonconventionalSiO2dielectricshavebeeninvestigated.Now,anenormousamountofeffortwasrequiredtoadaptthenewhigh-ksystemsforradiationhardapplication.
简介:Chemical-loopingcombustion(CLC)isanovelcombustiontechniquewithinherentCO2separation.Magnetite(Fe3O4)wasselectedastheoxygencarrier.Shenhuacoal(InnerMongolia,China),strawcokeandnaturalcokewereusedasfuelsforthisstudy.Influencesofoperationtemperatures,coaltoFe3O4massratios,anddifferentkindsoffuelsonthereductioncharacteristicsoftheoxygencarrierwereinvestigatedusinganatmospherethermogravimetricanalyzer(TGA).Scanningelectronmicroscopy(SEM)wasusedtoanalysethecharacteristicofthesolidresidues.Experimentalresultsshownthatthereactionbetweenthecoalandtheoxygencarrierbecomestrongatatemperatureofhigherthan800℃.Astheoperationtemperaturerises,thereductionconversionrateincreases.Atthetemperaturesof850oС,900℃,and950℃,thereductionconversionrateswere37.1%,46.5%,and54.1%respectively.However,SEMimagesshowthatatthetemperatureofhigherthan950℃,theironoxidesbecomemeltedandsintered.Thepossibleoperationtemperatureshouldbekeptaround900℃.WhenthemassratiosofcoaltoFe3O4were5/95,10/90,15/85,and20/80,thereductionconversionrateswere29.5%,40.8%,46.5%,and46.6%respectively.Withtheincreaseofcoal,theconversionrategoesup.Butthereexistanoptimalratioaround15/85.Comparisonsbasedondifferentkindsoffuelsshowthatthesolidfuelwithahighervolatileandamoredevelopedporestructureisconducivetothereductionreactivityoftheoxygencarrier.
简介:Photocatalyticwatersplittingandcarbondioxidereductionprovideuscleanandsustainableenergyresources.Thecarbondioxidereductionisalsotheredemptionofthegreenhouseeffect.MoS3/TiO2photocatalystsbasedonTiO2nanoplateshavebeensynthesizedviaahydrothermalacidificationrouteforwaterandcarbondioxidereductionreactions.ThisfacileapproachgenerateswelldispersedMoS3withlowcrystallinityonthesurfaceofTiO2nanoplates.Theas-synthesizedMoS3/TiO2photocatalystshowedconsiderableactivityforbothwaterreductionandcarbondioxidereduction.ThethermaltreatmenteffectsofTiO2,theloadingpercentageofMoS3andthecrystallinephaseofTiO2havebeeninvestigatedtowardsthephotocatalyticperformance.TiO2nanoplatesynthesizedthroughhydrothermalreactionwiththepresenceofHFacidisanidealsemiconductormaterialfortheloadingofMoS3forphotocatalyticwaterandcarbondioxidereductionsimultaneouslyinEDTAsacrificialsolution.
简介:Inthispaper,carbonmicrospherepreparedbyhydrothermaltreatmentwasactivatedbyKHCO3athightemperature,andemployedasthecatalystforVO2+/VO2+redoxreactionforvanadiumredoxflowbattery(VRFB).CarbonmicrospherecanbeetchedbyKHCO3duetothereactionbetweenthepyrolysisproductsofKHCO3andcarbonatoms.Moreover,KHCO3activationcanbringmanyoxygenfunctionalgroupsoncarbonmicrosphere,furtherimprovingthewettabilityofcatalystandincreasingtheactivesites.Theelectrocatalyticpropertiesofcarbonmicrospherefromhydrothermaltreatmentareimprovedbyhightemperaturecarbonization,andcanfurtherbeenhancedbyKHCO3activation.Amongcarbonmicrospheresamples,theVO2+/VO2+redoxreactionexhibitsthehighestelectrochemicalkineticsonKHCO3activatedsample.ThecellusingKHCO3activatedcarbonmicrosphereasthepositivecatalystdemonstrateshigherenergyefficiencyandlargerdischargecapacity,especiallyathighcurrentdensity.TheresultsrevealthatKHCO3activatedcarbonmicrosphereisanefficient,low-costcarbon-basedcatalystforVO2+/VO2+redoxreactionforVRFBsystem.
简介:WehavecomprehensivelyinvestigatedthefrustratedJ1-J2-J3Heisenbergmodelonasimplecubiclattice.Thismodelallowsthreeregimesofmagneticorder,viz.,(π;π;π),(0;π;π)and(0;0;π),denotedasAF1,AF2,andAF3,respectively.Theeffectsoftheinterplayofneighboringcouplingsonthemodelarestudiedintheentiretemperaturerange.Thezerotemperaturemagneticpropertiesofthismodelarediscussedutilizingthelinearspinwave(LSW)theory,nonlinearspinwave(NLSW)theory,andGreen’sfunction(GF)method.ThezerotemperaturephasediagramsevaluatedbytheLSWandNLSWmethodsareillustrated,andareobservedtoexhibitdifferentparameterboundaries.Incertainregionsandalongtheparameterboundaries,thepossiblephasetransformationsdrivenbytheparametersarediscussed.TheresultsobtainedusingtheLSW,NLSW,andGFmethodsarecomparedwiththoseobtainedusingtheseriesexpansion(SE)method,andareobservedtobeingoodagreementwhenthevalueofJ2isnotclosetotheparameterboundaries.ThegroundstateenergiesobtainedusingtheLSWandNLSWmethodsareclosetothatobtainedusingtheSEmethod.Atfinitetemperatures,onlytheGFmethodisemployedtoevaluatethemagneticproperties,andthecalculatedphasediagramisobservedtobeidenticaltotheclassicalphasediagram.Theresultsindicatethatattheparameterboundaries,atemperature-drivenfirst-orderphasetransitionbetweenAF1andAF2mayoccuralongtheboundaryline.AlongtheAF1-AF3andAF2-AF3boundarylines,AF3islessstablethanAF1andAF2.OurcalculatedcriticaltemperatureagreeswiththatobtainedusingMonteCarlosimulationsandpseudofermionfunctionalrenormalizationgroupscheme.
简介:Thesuppressionoftherecombinationofelectronsandholes(e–h)andtheenhancementofthelightabsorptionofsemiconductorsaretwokeypointstowardefficientphotocatalyticdegradation.Here,wereportafew-layerg-C3N4/α-MoO3nanoneedles(flg-C3N4/α-MoO3NNs)all-solid-stateZ-schememechanismphotocatalystsynthesizedviaatypicalhydrothermalmethodinacontrolledmanner.Therecombinationofthephoto-inducede–hpairscouldbeeffectivelyrestrainedbytheZ-schemepassagewaybetweentheflg-C3N4andα-MoO3NNsinthecomposite,whichcouldalsopromiseahighredoxabilitytodegradepollutants.Anditbecamepossibleforthepreparedphotocatalysttoabsorblightinawiderangeofwavelengths.Thedetailedmechanismwasstudiedbyelectronspin-resonancespectroscopy(ESR).Thelow-dimensionalnanostructureofthetwoconstituents(α-MoO3NNswithone-dimensionalstructureandflg-C3N4withtwo-dimensionalstructure)endowedthecompositewithvarietiesofexcellentphysicochemicalproperties,whichfacilitatedthetransferanddiffusionofthephotoelectronsandincreasedthespecificsurfaceareaandtheactivesites.The10wt%flg-C3N4/α-MoO3NNsshowedthebestphotocatalyticperformancetowardRhBdegradation,therateofwhichwas71.86%,~2.6timeshigherthanthatofα-MoO3NNs.
简介:ThisworkismainlytostudytheeffectofheavyionirradiationonthedamageofsinglelayerMoS2.ThenumberoflayersofMoS2preparedbyCVD(chemicalvapordeposition)methodwasdeterminedbyopticalmicroscopyandRamanspectroscopy.ThemonolayerMoS2preparedbyCVDunderhighenergy209BiionirradiationwasanalyzedbyRamananalysisandAFMobservation.AndtheresultsarecomparedandanalyzedbeforeandafterthebeamirradiationofsinglelayerMoS2preparedbymechanicalstrippingmethod.
简介:TheinteractionprocessofionsandplasmasisanimportanttopicinIon-Beam-DrivenHighEnergyDensityPhysicsandInertialConfinementFusionresearch.Duetothestrongnon-lineareffectsandthespecialimportanceinICFresearch,moreandmoreemphasishasbeengiventotheinvestigationsforionbeaminlowenergyrangeand/orforplasmawithhighintensity[1;2].Here,weaddressthenewlymeasuredresultsoftheenergylossbyslowionspenetratingthefullyionizedhydrogenplasmatarget.
简介:Fe_(3–x)O_4raspberryshapednanostructures/graphenenanocompositesweresynthesizedbyaone-steppolyol-solvothermalmethodtobetestedaselectrodematerialsforLi-ionbattery(LIB).Indeed,Fe_(3–x)O_4raspberryshapednanostructuresconsistoforiginalorientedaggregatesofFe_(3–x)O_4magnetitenanocrystals,ensuringalowoxidationstateofmagnetiteandahollowandporousstructure,whichhasbeeneasilycombinedwithgraphenesheets.TheresultingnanocompositepowderdisplaysaveryhomogeneousspatialdistributionofFe_(3–x)O_4nanostructuresatthesurfaceofthegraphenesheets.TheseoriginalnanostructuresandtheirstronginteractionwiththegraphenesheetsresultedinverysmallcapacityfadinguponLi+ionintercalation.Reversiblecapacity,ashighas660mAh/g,makesthismaterialpromisingforanodeinLi-ionbatteriesapplication.
简介:Two-dimensional(2D)graphitecarbonnitride(g-C3N4)nanosheetshavebeensuccessfullyusedasasaturableabsorber(SA)inapassivelyQ-switchedNd:LLFlaserat1.3μmforthefirsttime,tothebestofourknowledge.Underanincidentpumppowerof9.97W,theshortestpulsedurationof275nswasacquiredwithoutputpowerof0.96Wandpulserepetitionrateof154kHz,resultinginapulseenergyof6.2μJ.Inaddition,thesaturableabsorptionbehaviorsofzero-dimensional12nmg-C3N4nanoparticles(g-C3N4-NPs)andthree-dimensionalorderedmesoporousg-C3N4(mpg-C3N4)werealsoobserved,althoughtheirmorphologyandstructurewerequitedifferentfrom2Dg-C3N4.Theexperimentalresultsintroducethepotentialapplicationofg-C3N4nanomaterialsasSAsinQ-switchedlasers.