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简介：UsingtheaveragingtheoryoffirstandsecondorderwestudythemaximumnumberoflimitcyclesofgeneralizedLinarddifferentialsystems{x=y+εhl1（x）+ε2hl2（x）,y=-x-ε(fn1（x）y2p+1+gm1（x）)+∈2(fn2（x）y2p+1+gm2（x）),whichbifurcatefromtheperiodicorbitsofthelinearcenterx=y,y=-x,whereεisasmallparameter.Thepolynomialshl1andhl2havedegreel;fn1andfn2havedegreen;andgm1,gm2havedegreem.p∈Nand[·]denotestheintegerpartfunction.

简介：TheelectrochemicalformationofMg-LialloyswasinvestigatedinamoltenLiCl-KCl(58-42mol%)eutecticmeltat723K.ThecyclicvoltammogramforaMoelectrodeshowedthattheelectroreductionofLi~+proceedsinasinglestepandthedepositionpotentialofLimetalwas-2.40V(vs.Ag/AgCl).ForMgelectrode,theelectroreductionofLi~+takesplaceatlesscathodicpotentialthanthatattheMoelectrodewhichwascausedbytheformationofMg-Lialloys.PhaseofthedepositedMg-Lialloyscouldbecontrolledbytheelectrolysispotential,andthesampleswerecharacterizedbyX-raydiffractionandscanningelectronmicroscopy.Theresultsshowedthatα-Mgandβ-Liphaseswereobtainedat-2.35and-2.55V,respectively.

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.

简介：本文对文给出的提出的一个极限环存在性定理的简化证明的关键一步做了进一步的简化。

简介：Holloworderedporouscarbonspheres（HOPCS）withahierarchicalstructurewerepreparedbytemplatingwithholloworderedmesoporoussilicaspheres（HOMSS）.Scanningelectronmicroscopy（SEM）andtransmissionelectronmicroscopy（TEM）showedthatHOPCSexhibitedasphericalhollowmorphology.High-resolutionTEM,smallangleX-raydiffraction（SAXRD）andN2sorptionmeasurementsconfirmedthatHOPCSinverselyreplicatedtheunconnectedhexagonal-stackedporestructureofHOMSS,andpossessedorderedporosity.HOPCSexhibitedahigherstoragecapacityforLi+ionbattery（LIB）of527.6mAh/g,andgoodcyclingperformance.Alargecapacitylossduringthefirstdischarge-chargecyclewasfoundattributedtothehighcontentofmicropores.Thecyclingperformancewasderivedfromthehierarchicalstructure.

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简介：本文探讨（CH3Li）4中键的作用,通过计算,发现（CH3Li）4分子的面甲基结构比顶甲基结构要稳定;指出Li—Li间的成键作用相当强,约为Li2分子中键作用的40%左右,估计（CH3Li）4中的J7Li-6Li值约为1Hz。

简介：Lithiation-inducedplasticityisakeyfactorthatenablesSielectrodestomaintainlongcyclelifeinLi-ionbatteries.Westudytheplasticityofvariouslithiatedsili-conphasesbasedonfirst-principlescalculationsandiden-tifythelineardependenceoftheequivalentyieldstressonthehydrostaticpressure.Suchdependencemaycausethecompression-tensionasymmetryinanamorphousSithinfilmelectrodefromalithiationtodelithiationcycle,andleadstosubsequentratchetingoftheelectrodeaftercycliclithiation.Weproposeayieldcriterionofamorphouslithi-atedsiliconthatincludestheeffectsofthehydrostaticstressandthelithiationreaction.Wefurtherexaminethemicro-scopicmechanismofdeformationinlithiatedsiliconundermechanicalload,whichisattributedtotheflow-defectsmediatedlocalbondswitchingandcavitation.Hydrostaticcompressionconfinestheflowdefectsthuseffectivelystrength-enstheamorphousstructure,andviceversa.

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简介：NanoporousanataseTiO2(np-TiO2)electrodeshavebeendevelopedviatheanodizationoftitaniumfoilsinfluoridecontainingelectrolytes,anditsapplicationinrechargeablelithium-ionbatteries(LIBs)wasinvestigated.Fourdifferenttypesofnp-TiO2electrodeswithdifferentporediametersof14.7±8.2nm,12.8±6.8nm,11.0±5.5,and26.7±13.6nmwerefabricatedforevaluatingtheeffectofnanoporouscharacteristicsontheLIBperformance.Thedischargecapacityofthefourbatterytypes1,2,3,and4were132.7mAhg-1,316.7mAhg-1,154.3mAhg-1,and228.4mAhg-1,respectively.Inaddition,theseelectrodes1,2,3,and4exhibitedreversiblecapacityof106.9mAhg-1after295th,180.9mAhg-1after220th,126.1mAhg-1after150th,and206.7mAhg-1after85thcycleatarateof1C,respectively.Itwasnotedthatthecycliclifeofthebatterieshadaninverserelationship,andthecapacityhadaproportionalrelationshiptotheporediameter.Theenhancedelectrochemicalperformanceofthenanoporouselectrodescanbeattributedtotheimprovedconductivityandtheenhancedkineticsoflithiuminsertion/extractionatelectrode/electrolyteinterfacesbecauseofthelargespecificsurfaceareaofnp-TiO2electrodes.

简介：Lithiumsulfurbattery(LSB)offersseveraladvantagessuchasveryhighenergydensity,low-cost,andenvironmental-friendliness.However,itsuffersfromseriousdegradationofitsreversiblecapacitybecauseofthedissolutionofreactionintermediates,lithiumpolysulfides,intotheelectrolyte.Tosolvethislimitation,therearemanystudiesusinggraphene-basedmaterialsduetotheirexcellentmechanicalstrengthandhighconductivity.Comparedwithgraphene,grapheneoxide(GO)containsvariousoxygenfunctionalgroups,whichenhancethereactionwithlithiumpolysulfides.Here,weinvestigatedthepositiveeffectofusingGOmixedwithcarbonblackontheperformanceofcathodeinLSB.WehaveobservedasmallerdropofcapacityinGOmixedsulfurcathode.Wefurtherdemonstratethatthemechanisticoriginofreversibilityimprovement,asconfirmedthroughCVandRamanspectra,canbeexplainedbythestabilizationofsulfurinlithiumpolysulfideintermediatesbyoxygenfunctionalgroupsofGOtopreventdissolution.Ourfindingssuggestthattheuseofgrapheneoxide-basedcathodeisapromisingroutetosignificantlyimprovethereversibilityofcurrentLSB.

简介：BycombiningtheB-splinebasissetwithmodelpotential(B-spline+MP),wepresentoscillatorstrengthspectraofRydbergLiatomsinexternalfields.Thephotoabsorptionspectraareanalyzed.Overthenarrowenergyrangesconsideredinthispaper,thestructureofthespectracanbeindependentoftheinitialstatechosenforagivenatom.Ourresultsareingoodagreementwithprevioushigh-precisionexperimentaldataandtheoreticalcalculations,wheretheR-matrixapproachtogetherwithmultichannelquantumdefecttheory(R-matrix+MQDT)wasused.ItissuggestedthatthepresentmethodscanbeappliedtodealwiththeoscillatorstrengthspectraofRydbergatomsincrossedelectricandmagneticfields.

简介：Inordertodeepentheunderstandingoftherelationshipbetweenfundamentalproperties（including:microstructureandcomposition）andphotocatalyticperformance,fourbismuthatecompounds,including:LiBiO3,NaBiO3,KBiO3,andAgBiO3,areregardedasresearchexamplesinthepresentwork,becausetheyhaveparticularcrystalstructuresandsimilarcompositions.Usingdensityfunctionaltheorycalculations,theirstructural,electronic,andopticalpropertiesareinvestigatedandcomparedsystematically.Firstofall,thecalculatedresultsofcrystalstructuresandopticalpropertiesareinagreementwithavailablepublishedexperimentaldata.Basedonthecalculatedresults,itisfoundthatthetunneledorlayeredmicro-structuralpropertiesleadtothestrongerinteractionbetweenbismuthandoxygen,andtheweakerinteractionbetweenalkaline-earthmetaland[BiO6]octahedron,resultinginthefeatureofmulti-bandgapsinthecasesofLiBiO3,NaBiO3,andKBiO3.ThisconclusionissupportedbythecaseofAgBiO3,inwhichthefeatureofmulti-bandgapsdisappears,duetothestrongerinteractionbetweenthenoblemetaland[BiO6]octahedron.Thesepropertieshavesignificantadvantagesinthephotocatalyticperformance:absorbinglowenergyphotons,rapidlytransferringenergycarriers.Furthermore,thefeaturesofelectronicstructuresofbismuthatecompoundsarewellreflectedbytheabsorptionspectra,whichcouldbeconfirmedbyexperimentalmeasurementsinpractice.Combinedwiththecalculatedresults,itcouldbeconsideredthatthecrystalstructuresandcompositionsofthephotocatalystdeterminetheelectronicstructuresandopticalproperties,andsubsequentlydeterminethecorrespondingphotocatalyticperformance.Thus,anovelBi-basedphotocatalystdrivenbyvisible-lightcouldbedesignedbyutilizingspecificcompositionstoformfavorableelectronicstructuresorspecificmicro-structurestoformabeneficialchannelforenergycarriers.

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简介：Inthispaper,westudytheglobalasymptotiestabilityofthezerosolutionofageneralizedLienard'ssystem{x^.=φ(y)y^.=-f(x)φ(y)-g(x)byconstructinganewLiapunovfunction.Thesufficientandneoessaryconditionsforglobalasymptoticstabilityundergivenconditionsareobtained.

简介：Li0.33MnO2cathodematerialwassynthesizedbysolidstatereaction.Thematerialshowedasmallcoherentdomainsizeabout10nmdeterminedbyX-raydiffractionandtransmissionelectronmicroscopy.Theelectrochemicalpropertiesofthematerialwerestudiedindifferentpotentialwindowsof3.5―2.0Vand4.3―2.0V.Anirreversibletransformationtospinelphasewasobservedintheinitialseveralcycles,whichwasmoreprominentoncyclingat4.3―2.0V.ElectrochemicalimpedancespectroscopyshowedthattheLi+diffusioncoefficientofthematerialwasabout2×10–9cm2/s.Li0.33MnO2showedareversibledischargecapacityof140and200mA·h/ginthepotentialwindowsof3.5―2.0Vand4.3―2.0V,respectively.Butthecapacityretentionat4.3―2.0Vwaspoorduetothethickerspinellayerformedonthematerialsurface.