简介:
简介:Inthispaper,westudytheCauchyproblemforthe3DgeneralizedNavier-Stokes-Boussinesqequationswithfractionaldiffusion:{ut+(u·▽)u+v∧2αu=-▽p+θe(3),e3=(0,0,1)T,θt+(u·▽)θ=0,Dicu=0.Withthehelpofthesmoothingeffectofthefractionaldiffusionoperatorandalogarithmicestimate,weprovetheglobalwell-posednessforthissystemwithα≥5/4.Moreover,theuniquenessandcontinuityofthesolutionwithweakerinitialdataisbasedonFourierlocalizationtechnique.Ourresultsextendonesonthe3DNavier-Stokesequationswithfractionaldiffusion.
简介:Inthispaper,weinvestigatetheglobalexistenceandlongtimebehaviorofstrongsolutionsforcompressiblenematicliquidcrystalflowsinthreedimensionalwholespace.TheglobalexistenceofstrongsolutionsisobtainedbythestandardenergymethodundertheconditionthattheinitialdataareclosetotheconstantequilibriumstateinH~2-framework.IftheinitialdatasinL~1-normarefiniteadditionally,theoptimaltimedecayratesofstrongsolutionsareestablished.WiththehelpofFouriersplittingmethod,onealsoestablishesoptimaltimedecayratesforthehigherorderspatialderivativesofdirector.
简介:Newmetal-freeorganicdyesensitizerscontainingmono-triphenylamineorbis-triphenylamineastheelectrondonor,athiopheneastheπ-conjugatedsystem,andacyanoacrylicacidmoietyastheelectronacceptorweresynthesized.Theopticalandelectrochemicalpropertiesofthedyeswereinvestigated,andtheirperformanceassensitizersinsolarcellswasevaluated.Dye-sensitizedsolarcellsbasedondyecontainingbis-triphenylamineastheelectrondonorproducedaphoton-to-currentconversionefficiencyof6.06%(Jsc=14.21mA/cm~2,Voc=0.62V,ff=0.69)under100mW/cm~2simulatedAM1.5Gsolarirradiation(100mW/cm~2).
简介:利用L-脯氨酸催化的5-氯水杨醛(1)与6-甲基-4-羟基吡喃酮(2)的缩合反应及硫酸铜催化下与1,3-二甲基-5-氨基吡唑(3)的串联反应,合成得到了10-氯-1,3-二甲基-5-(2-氧代丙基)色烯并[4,3-d]吡唑并[3,4-b]吡啶-6(3H)-酮(4)和10-氯-5-二乙氧基甲基-1,3-二甲基色烯并[4,3-d]吡唑并[3,4-b]吡啶-6(3H)-酮(5).化合物5的结构通过单晶X射线衍射法确定:晶体属于三斜晶系,空间群P-1;相对分子质量Mr=803.68;晶胞参数a=1.03160(10)nm,b=1.42900(13)nm,c=1.44268(15)nm;V=1.9448(3)nm~3;Z=2;晶胞密度Dc=1.372g/cm~3;吸收系数μ=0.228mm-1;单胞中电子的数目F(000)=840.晶体结构用直接法解出,经全矩阵最小二乘法对原子参数进行修正,最终的偏离因子为R=0.0681,wR=0.2051.在晶体结构中色烯环与吡啶环及吡唑环近似于共平面.
简介:Multilayerblackphosphorus(BP)nanoplateletsofdifferentthicknesseswerepreparedbytheliquidphaseexfoliationmethodanddepositedontoyttriumaluminumgarnetsubstratestoformsaturableabsorbers(SAs).Thesewerecharacterizedwithrespecttotheirthickness-dependentsaturableabsorptionpropertiesat3μm.TheBP-SAswereemployedinapassivelyQ-switchedEr:Lu2O3laserat2.84μm.ByusingBPexfoliatedindifferentsolvents,stablepulsesasshortas359nsweregeneratedatanaverageoutputpowerofupto755mW.Therepetitionrateintheexperimentwas107kHz,correspondingtoapulseenergyof7.1μJ.TheseresultsprovethatBP-SAshaveagreatpotentialforopticalmodulationinthemid-infraredrange.
简介:采用CBS-QB3方法构建了丙烯酸甲酯(CH_2=CHCOOCH_3)与O_3反应体系的势能剖面并在此基础上利用经典过渡态理论(TST)和Wigner矫正模型计算了标题反应在200K~1200K温度区间内的速率常数kTST/W.研究结果表明,CH_2=CHCOOCH)3与O)3反应首先经过渡态生成一个稳定的五元环中间体,然后按断键位置不同,分别生成产物P1(CH_3OCOCHO+CH_2O_2)和P2(CH)3OCOCHOO+HCHO).此外,速率常数结果显示,在计算温度范围内,标题反应速率常数呈正温度系数效应.294K时,CH_2=CHCOOCH_3与O_3反应速率常数为1.76×10^(-18)cm^3·molecule^(-1)·s^(-1),与所测实验值(0.95±0.07)×10^(-18)cm^3·molecule^(-1)·s^(-1)非常接近.
简介:Anewmethodforfabricatingorderedporoussiliconisreported.Atwo-dimensionalsilicananospherearrayisusedasatemplatewithahydrofluoricacid-hydrogenperoxidesolutionforetchingthenanospheres.Theinitialdiameteranddistributionoftheholesintheresultingporoussiliconlayeraredeterminedbythesizeanddistributionofthesilicananospheres.Thecorrosiontimecanbeusedtocontrolthedepthsoftheholes.ItisfoundthatthepresenceofaSiO_2layer,formedbytheoxidationoftheroughinternalsurfaceofthehole,istheprimaryreasonallowingthecorrosiontoproceed.Ultravioletreflectionandthermalconductivitymeasurementsshowthatthediameteranddistributionoftheholeshaveagreatinfluenceonpropertiesoftheporoussilicon.
简介:FranklandFürediin[1]conjecturedthatther-graphwithmedgesformedbytakingthefirstmsetsinthecolexorderingofN(r)hasthelargestLagrangianofallr-graphswithmedges.Denotethisr-graphbyCr,mandtheLagrangianofahypergraphbyλ(G).Inthispaper,wefirstshowthatif(3t-1)≤m<(3t),Gisaleft-compressed3-graphwithmedgesandonvertexset[t],thetriplewithminimumcolexorderinginGcis(t—2—i)(t—2)t,thenλ(G)≤λ(C3,m).Asanimplication,theconjectureofFranklandFiirediistruefor(3t)-6≤m≤(3t).
简介:Fornon-negativeintegersi,jandk,wedenotethegeneralizednetasN_(i,j,k),whichisatrianglewithdisjointpathsoflengthi,jandk,attachedtodistinctverticesofthetriangle.Inthispaper,weprovethatevery3-connected{K_(1,3),N_(8-i,i,1}-freegraphishamiltonian,where1≤i≤4.
简介:本文讨论了求解Sylvester方程AXB+CX=D的OROD迭代法(正交残量法和正交方向迭代法)的几个重要性质,证明了该算法产生的误差序列是单调递减的,同时给出了该算法的最小化性质的精确刻画,最后给出了一些数值例子.
简介:Inthispaper,wefirstshowtheglobalexistence,uniquenessandregularityofweaksolutionsforthehyperbolicmagnetohydrodynamics(MHD)equationsinR~3.ThenweestablishthatthesolutionswithinitialdatabelongingtoH~m(R~3)∩L~1(R~3)havethefollowingtimedecayrate:║▽~mu(x,t)║~2+║▽~mb(x,t)║~2+║▽~(m+1)u(x,t)║~2+║▽~(m+1)b(x,t)║~2≤c(1+t)~(-3/2-m)forlarget,wherem=0,1.
简介:Molybdenumoxidenanostructuredthinfilmsweregrownonfluorinedopedtinoxide(FTO),indiumdopedtinoxide(ITO)andordinaryglasssubstratesbythermalevaporationprocesswithoutvacuumandcatalystsusingmolybdenumtrioxide(MoO3)powderasasourcematerialandoxygenasacarriergas.Variousmorphologiesincludingnanobelts,disksandhexagonalrod-likenanostructureswereobtainedbychangingthesourceandsubstratetemperaturesduringthegrowthofMoO3thinfilms.Structuralparameters,morphology,compositionandsurfacefeaturesofthefilmswerecharacterizedbyXRD,SEM,EDAX,XPS,AFMandRamanspectroscopy.Thefilmswereorthorhombicinstructurewithpreferredorientationalong(010)plane.Morphologyanalysisrevealsrandomlyalignednanobeltswith40nminthicknessandawidthof800nmand3–12mminlength.Thediskshave1.5μmdiameters,1μmthicknessandhexagonalrod-likenanostructureswithalength,breathandwidthof2μm,1μmand100nmareformed.ThesampleswereinvestigatedunderdarkandphotocurrentconditionsinH2SO4aqueoussolutionasafunctionofappliedpotential.ThephotocurrentdensityofsamplespreparedonITOandFTOsubstratesampleswerecomparedandtheresultsarediscussed.
简介:磁铁矿(Fe3有不同尺寸和形状的O4)nanoparticles被热分解方法综合。二条途径,非注射一个壶和热注射的方法,被设计详细调查生长机制。nanoparticles的尺寸和形状被调整先锋集中和持续时间时间决定,这被发现,它能好在我们的合成系统基于LaMer模型由机制解释了。monodisperseFe3O4nanoparticles从5nm有一条吝啬的直径到16nm,和形状进化从对球形三角形、立方。磁性是尺寸依赖者,和Fe3在关于在房间温度和最大的浸透磁化的5nm展览superparamagnetic性质的小尺寸的O4nanoparticles来临到78emu/g,而Fe3O4nanoparticles当直径增加到大约16nm时,开发铁磁性的性质。
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.
简介:Wereportthestudyofalowtemperatureclusterglassstatein5%Mn-dopedUGa3heavyfermioncompound.Thiscompoundtransformsfromaparamagneticstatetoaspin-clusterglassstate,whichisconfirmedbymeasuringthedcsusceptibilityandmagnetization.Theacsusceptibilityexhibitsafrequency-dependentpeakaroundTf,whichprovidesdirectevidenceoftheclusterglassstate.Byanalyzingthefield-dependentmagnetizationandfrequency-dependentacsusceptibilityindetail,wededucethatthiscompoundformsaspin-clusterglassstatebelowTf.
简介:Photocatalyticwatersplittingandcarbondioxidereductionprovideuscleanandsustainableenergyresources.Thecarbondioxidereductionisalsotheredemptionofthegreenhouseeffect.MoS3/TiO2photocatalystsbasedonTiO2nanoplateshavebeensynthesizedviaahydrothermalacidificationrouteforwaterandcarbondioxidereductionreactions.ThisfacileapproachgenerateswelldispersedMoS3withlowcrystallinityonthesurfaceofTiO2nanoplates.Theas-synthesizedMoS3/TiO2photocatalystshowedconsiderableactivityforbothwaterreductionandcarbondioxidereduction.ThethermaltreatmenteffectsofTiO2,theloadingpercentageofMoS3andthecrystallinephaseofTiO2havebeeninvestigatedtowardsthephotocatalyticperformance.TiO2nanoplatesynthesizedthroughhydrothermalreactionwiththepresenceofHFacidisanidealsemiconductormaterialfortheloadingofMoS3forphotocatalyticwaterandcarbondioxidereductionsimultaneouslyinEDTAsacrificialsolution.