简介:目的:探索1T-MoS2(多型结构的二硫化钼)的除汞机制。方法:1.采用密度泛函理论(DFT)分析Hg~0在1T-MoS_2单层上的吸附机理。2.考察1T-MoS_2的不同吸附位置。3.对不同的吸附构型,研究电子吸附前后的变化,从而进一步了解吸附过程。结论:1.化学吸附是Hg原子与1T-MoS_2单层吸附的主导因素。同时,在所有可能的吸附位置中,T_(Mo)(在钼原子上方)的位置是最强烈的吸附构型。2.汞(Hg)原子在1T-MoS_2单层上的吸附受邻近的硫(S)和钼(Mo)原子的影响。3.吸附的汞(Hg)原子在1T-MoS_2的Tmo位置上会被氧化,其吸附能为-1.091eV。4.从局部态密度(PDOS)分析来看,Hg原子和1T-MoS_2表面之间的相互作用是由汞(Hg)原子的d轨道与硫(S)原子的s轨道及钼(Mo)原子的p轨道和d轨道重叠所致。
简介:现在的汽车上有很多电力驱动装置。从车窗的起落装置到电动助力转向系统,各种不同的动力都是由不同的电机和电子元器件组合来提供和实现的。用来驱动这些应用装置的变换器一般是由几个N沟道场效应管,一个驱动集成电路,一个微处理器,和通信与电源设备组成。典型的应用是驱动电动机的功率开关,只有一个H桥拓扑或是三相桥结构。作为微处理器和功率场效应管的接口,驱动电路将提供给场效应管的栅极必要的电流和电压,以保证它达到安全和预期的开关性能。针对汽车对于安全性方面的较高要求,一些保护功能也被纳入到驱动电路中,比如短路保护和过温保护。本文主要介绍一种新的方法,即用一个P沟道MOS场效应管作为高压端开关,而一个N沟道MOS场效应管作为低压端开关。先介绍其优点,再分析它的缺点。此外,本文还介绍P/N沟道组合的驱动集成电路,此电路现在市场上没有出现。
简介:使用扫描电镜观察和分析了滚压不锈钢钢管的成型模具的表面磨损特性和形貌,分析了粘着磨损的形成机理,研究并制备了电刷镀Ni—w(D).MoS2复合镀层修复了已磨损的模具.结果表明,镀层明显改善了模具表面的抗粘着磨损性能,使模具的使用寿命明显提高,并取得了良好的经济效益.
简介:Thecounterelectrode(CE)prominenceindye-sensitizedsolarcells(DSSCs)isundisputedwithresearchgearedtowardsreplacementofPtwithviablesubstituteswithexceptionalconductivityandcatalyticactivity.Herein,wereportthereplaceableCEwithbetterperformancethanthatofPt-basedelectrode.ThechemistrybetweenthegrapheneoxideandicetemplatesleadstocellularformationofreducedgrapheneoxidethatachievesgreaterconductivitytotheCE.Thesimultaneousgrowthofactiveedge-orientedMoS2ontheCEthroughCVDpossesseshighreflectivity.HighreflectiveMoS2trendstoincreasetheelectroactivitybyabsorbingmorephotonsfromthesourcetodyemolecules.Thus,thesynergisticeffectoftwomaterialswasfoundtoshowcasebetterphotovoltaicperformanceof7.6%against7.3%fortraditionalplatinumCE.
简介:Liquid-phase-exfoliationtechnologywasutilizedtopreparelayeredMoS2,WS2,andMoSe2nanosheetsincyclohexylpyrrolidone.Thenonlinearopticalresponseofthesenanosheetsindispersionswasinvestigatedbyobservingspatialself-phasemodulation(SSPM)usinga488nmcontinuouswavelaserbeam.ThediffractionringpatternsofSSPMwerefoundtobedistortedalongtheverticaldirectionrightafterthelasertraversingthenanosheetdispersions.Thenonlinearrefractiveindexofthethreetransitionmetaldichalcogenidesdispersionsn2wasmeasuredtobe10-7cm2W-1,andthethird-ordernonlinearsusceptibilityχ(3)10-9esu.TherelativechangeofeffectivenonlinearrefractiveindexΔn2e∕n(2e)oftheMoS2,WS2,andMoSe2dispersionscanbemodulated0.012–0.240,0.029–0.154,and0.091–0.304,respectively,bychangingtheincidentintensities.Ourexperimentalresultsimplynovelpotentialapplicationoftwo-dimensionaltransitionmetaldichalcogenidesinnonlinearphasemodulationdevices.
简介:Wereportanerbium-dopedfiberlaserpassivelyQ-switchedbyafew-layermolybdenumdisulfide(MoS2)saturableabsorber(SA).Thefew-layerMoS2isgrownbythechemicalvapordepositionmethodandtransferredontotheend-faceofafiberconnectortoformafiber-compatibleMoS2SA.Thelasercavityisconstructedbyusingathree-portopticalcirculatorandafiberBragggrating(FBG)asthetwoend-mirrors.StableQ-switchedpulsesareobtainedwithapulsedurationof1.92μsat1560.5nm.Byincreasingthepumppowerfrom42to204mW,thepulserepetitionratecanbewidelychangedfrom28.6to114.8kHz.PassiveQ-switchingoperationswithdiscretelasingwavelengthsrangingfrom1529.8to1570.1nmarealsoinvestigatedbyusingFBGswithdifferentcentralwavelengths.Thisworkdemonstratesthatfew-layerMoS2canserveasapromisingSAforwideband-tunableQ-switchinglaseroperation.
简介:Thefundamentalmomentumconservationrequirementq~0fortheRamanprocessisrelaxedinthenanocrystallites(NCs),andphononsawayfromtheBrillouin-zonecenterwillbeinvolvedintheRamanscattering,whichiswell-knownasthephononconfinementeffectinNCs.ThisusuallygivesadownshiftandasymmetricbroadeningoftheRamanpeakinvariousNCs.Recently,theA'_1modeof1LMoS2NCsisfoundtoexhibitablueshiftandasymmetricbroadeningtowardthehigh-frequencyside[Chem.Soc.Rev.44(2015)2757andPhys.Rev.B91(2015)195411].Inthiswork,wecarefullycheckthisissuebystudyingRamanspectraof1LMoS2NCspreparedbytheionimplantationtechniqueinawiderangeofion-implanteddosage.ThesameconfinementcoefficientisusedforbothE'andA'_1modesin1LMoS_2NCssincethephononuncertaintyinanNCismainlydeterminedbyitsdomainsize.TheasymmetricalbroadeningneartheA′_1andE′modesisattributedtotheappearanceofdefect-activatedphononsatthezoneedgeandtheintrinsicasymmetricalbroadeningofthetwomodes,wheretheanisotropyofphonondispersioncurvesalongΓ-KandΓ-Misalsoconsidered.Thephotoluminescencespectraconfirmtheformationofsmalldomainsizeof1LMoS_2nanocrystallitesintheion-implanted1LMoS_2.Thisstudyprovidesnotonlyanapproachtoquicklyprobephonondispersiontrendsof2DmaterialsawayfromΓbytheRamanscatteringofthecorrespondingNCs,butalsoareferencetocompletelyunderstandtheconfinementeffectofdifferentmodesinvariousnanomaterials.
简介:WithMoS2assaturableabsorber,passiveQ-switchingandQ-switchedmode-lockingoperationsofaTm-dopedcalciumlithiumniobiumgalliumgarnet(Tm:CLNGG)laserwereexperimentallydemonstrated.TheQ-switchedlaseremittedamaximumaverageoutputpowerof62mWandhighestpulseenergyof0.72μJ.Q-switchedmodelockingwasalsoobtainedintheexperiment.TheresearchresultswillopenupapplicationsofMoS2atthemid-infraredwavelength.
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简介:Inpursuingexcellentsupercapacitorelectrodes,wedesignedaseriesofM0S2/C0S2compositesconsistingofflower-likedMoS2andoctahedron-shapedCoS2throughafacileone-stephydrothermalmethodandinvestigatedtheelectrochemicalperformanceofthesampleswithvarioushydrothermaltime.Duetothecouplingoftwometalspeciesandabigamountofwell-developedCoS2andMoS2,theresultsindicatedthattheMoS2/CoS2compositeselectrodesexhibitedthebestelectrochemicalperfor-mancewithalargespecificcapacitanceof490F/gat2mV/sor400F/gat10A/gamongallsamplesasthehydrothermaltimereached48h(MCS48).Furthermore,theretentionofMCS48is93.1%after10000cyclesat10A/g,whichmanifeststheexcellentcyclingstability.TheoutstandingelectrochemicalperformanceofMCS48indicatesthatitcouldbeaverypromisingandnovelenergystoragematerialforsupercapacitorsinthefuture.