简介:AKerr-lens,mode-lockedYVO4∕Nd:YVO4lasercoupledwithanacousto-opticmodulator(AOM)Q-switchingnear1064nmwasemployedtopumpanintracavityKTiOPO4(KTP)opticalparametricoscillator.Asubnanosecondsignalwavenear1572nmwithlowrepetitionratewasrealized.AtanAOMrepetitionrateof8kHz,themaximumoutputpowerwas165mW.Thehighestaveragepulseenergy,theshortestduration,andthehighestpeakpowerofamode-lockingsignalpulsewereestimatedtobe~10.3μJ,~120ps,and~82kW,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:4-(Succinimido)-1-butanesulfonicacidasanefficientandreusableBronstedacidcatalyzedthesynthesisofpyrano[4,3-b]pyranderivativesundersolvent-freeconditions.Thecatalystcanbepreparedbymixingsuccinimideand1,4-butanesultonethatismoresimpleandsaferthanthepreparationofsuccinimidesulfonicacid.Thismethodhastheadvantagesofhighyield,cleanreaction,simplemethodologyandshortreactiontime.Thecatalystcouldberecycledwithoutsignificantlossofactivity.
简介:Isochronousmassspectrometry(IMS)instorageringsisapowerfultoolformassmeasurementsofexoticnuclewithveryshorthalf-livesdowntoseveraltensofmicroseconds,usingamulticomponentsecondarybeamseparatedin-ightwithoutcooling.However,theinevitablemomentumspreadofsecondaryionslimitstheprecisionofnuclearmassesdeterminedbyusingIMS.
简介:CO2methanationhasbeenahottopicbecauseofitsimportantapplicationinthespacecraftandpotentialutilizationofcarbondioxide.Nickelcatalystisactiveforthisreaction.However,itsactivitystillneedstobeimproved.Dielectricbarrierdischarge(DBD)plasma,initiatedatambientconditionandoperatedat~150°C,hasbeenemployedinthisworkfordecompositionofnickelprecursortoprepareNi/MgAl2O4.Theplasmadecompositionresultsinhighdispersion,uniquestructure,enhancedreducibilityofNiparticlesandpromotedcatalyst-supportinteraction.AnimprovedactivityofCO2methanationwithahigheryieldofmethanehasbeenachievedovertheplasmadecomposedcatalyst,comparedtothecatalystpreparedthermally.Forexample,themethaneyieldoftheplasmapreparedcatalystis71.8%at300°Cbutitis62.9%overthethermalpreparedcatalyst.ThecatalystcharacterizationconfirmedthatCO2methanationovertheDBDplasmapreparedcatalystfollowspathwayofCOmethanation.
简介:Alinear4-nodequadrilateralquasi-conformingplaneelementwithinternalparametersisproposed.Theelementpreservesadvantagesofthequasi-conformingtechnique,includinganexplicitstiffnessmatrix,whichcanbeappliedtononlinearproblems.Theweakpatchtestguaranteestheconvergenceoftheelement.ThenthelinearelementisextendedtothegeometricallynonlinearanalysisintheframeworkofTotalLagrangian(TL)formulation.Thenumericaltestsindicatethatthepresentelementisaccurateandinsensitivetomeshdistortion.
简介:TheinfluenceofNa2SO4ontheformationofZnOwhiskerswasinvestigatedinthispaper.ZnOwhiskerswithaspectratiosofupto50weresynthesizedbydissolvingε-Zn(OH)2precursorinNaOH/Na2SO4solutionatroomtemperature,followedbyagingoftheresultingsolutionat140℃for6h.Fouriertransforminfraredspectroscopy,Ramanspectroscopy,andX-rayphotoelectronspectroscopyanalysesrevealedthatSO42-ionswereprimarilyadsorbedonthe(100)planeoftheZnOwhiskersviaanouter-spherecomplexconfiguration(O-H…O),therebypromotingtheone-dimensionalgrowthofZnOwhiskersalongthec-axis.
简介:Toeffectivelysolvetheagglomerationproblemsinthesolidstatereactionprocess,pre-addingglucoseisadoptedtothesynthesisofLiFePO4/CenergymaterialsusingFe–Pwasteslag.Theaverageparticle&grainsizeofLiFePO4/Cdecreases,andtheimpuritiesinLiFePO4/Ccompositesreducetoagreatextent.Itmakesgreatsensetothemassindustrialproduction.Theoptimumsynthesisconditionsdeterminedinthisworkarebasedontheorthogonalexperiments.Thesamplessynthesizedinascaleof500gexhibithighpurity,excellentelectrochemicalperformance,highreactionactivity,goodreversibility,andlowpolarizationlevel.Thedischargecapacitiesare145,134,117,and102mAh/gatthecurrentdensitiesof0.1C,0.2C,0.5Cand1C,respectively.ThisworkputsforwardapracticalsuggestionformassproducingenvironmentalbenignandlowcostLiFePO4/Cascathodematerialsoflithiumionbatteries.
简介:Amolybdenumdisulfide(MoS2)saturableabsorberwasfabricatedbythermallydecomposingtheammoniumthiomolybdate.ByusingtheMoS2absorber,acompactdiode-pumpedpassivelyQ-switchedTm:GdVO4laserhasbeendemonstrated.AstableQ-switchedlaserwithrepetitionratesfrom25.58to48.09kHzwasachieved.Maximumaverageoutputpowerwas100mWwiththeshortestpulsedurationof0.8μs.Maximumpulseenergyis2.08μJatcenterof1902nm.
简介:Weexperimentallydemonstratedadiode-pumpedKerr-lensmode-lockedfemtosecondlaserwithaYb:CaYAlO4crystalasthegainmedium.Pulsedurationasshortas33fswasobtaineddirectlyfromtheoscillatoratarepetitionrateof115MHz.Thecentralwavelengthwasat1059nmwithaspectralbandwidthof49nm.Theseare,tothebestofourknowledge,theshortestpulsesgeneratedfromaYb:CaYAlO4oscillator.
简介:对制造的单mesa终端4H-SiCPIN二极管,采用数值仿真和测试结果比对的方法,分析了各向异性迁移率效应对4H-SiCPIN二极管正向直流特性的影响。详细阐述了器件的正向直流仿真物理模型和参数选取,其中,迁移率的各向异性关系是在各向同性迁移率模型的基础上引入的,载流子寿命采用空间赋值的方法代入模型进行计算。对比结果显示,采用各向同性迁移率模型的仿真结果与实验值偏差较大,对迁移率模型进行各向异性修正后,仿真结果与实验结果符合得较好。研究表明,实际制造的4H-SiCPIN二极管在直流开态下,存在迁移率的各向异性效应。