简介:Inthispaper,blendmembranesfrompolyvinylacetate(PVAc)andblockcopolymerpoly(amide-12-b-ethyleneoxide)(Pebax1074)arepreparedbysolutioncastingandsolventevaporationmethod.Althoughtheyarehomogeneousonamacro-scale,theobservationsfromDSCandSEMindicatemicro-phaseseparationforPVAc/Pebax1074blendmembranes.WiththeincreaseofPebax1074content,gaspermeabilitiesofCO2,H2,N2andCH4allincreasegreatly.PVAc/Pebax1074blendmembraneswithhighPVAccontentareappropriateforCO2/CH4separation.Thetemperaturedependenceofgaspermeabilityisdividedintorubberyregionandglassyregion.Theactivationenergiesofpermeationinrubberyregionaresmallerthanthoseinglassyregion,andtheyalldecreasewithincreasingPebax1074content.ForN2,H2andCH4,theirgaspermeationpropertiesaremainlyinfluencedbythedual-modesorptionandhydrostaticpressureeffect.ButforCO2,itspermeabilityincreaseswiththeincreaseofpressureduetoCO2-inducedplasticizationeffect,whichismoreobviousforPVAc/Pebax1074blendmembraneswithhighPVAccontent.
简介:系统地研究了全平面收敛的B-值随机Difichlet级数的增长性,得到了在一定条件下,B-值随机Dirichlet级数在收敛平面上的增长(下)级几乎处处等于某Dirichlet级数的增长(下)级还得到了它们与指数和系数的关系式.
简介:Uponusingthedenotativetheoremofanti-HermitiangeneralizedHamiltonianmatrices,wesolveeffectivelytheleast-squaresproblemmin‖AX-B‖overanti-HermitiangeneralizedHamiltonianmatrices.WederivesomenecessaryandsufficientconditionsforsolvabilityoftheproblemandanexpressionforgeneralsolutionofthematrixequationAX=B.Inaddition,wealsoobtaintheexpressionforthesolutionofarelevantoptimalapproximateproblem.
简介:Inthisarticle,wecalculatethecontributionfromthenonfactorizablesofthadronicmatrixelementtothedecayB~0→χc1~π~0withthelight-conequantumchromo-dynamic(QCD)sumrules.Thenumericalresultsshowthatitscontributionisratherlargeandshouldnotbeneglected.Thetotalamplitudesleadtoabranchingfractionwhichisinagreementwiththeexperimentaldatamarginally.
简介:ThemethanolicextractfromaChineseendemicChrysanthemumplant,Dendranthemaindicumvar.aromaticum,wasfoundtoshowhighantifeedingactivityagainstPierisbrassicaeL.,andbybioassay-guidedseparation,theactivecomponent,B-ring-homo-tonghaosu,2-(2',4'-hexadiynylidene)-1,6-dioxaspiro-[4,5]-dec-3-ene(2)wasisolated.Itsstructurewaselucidatedbycomparingitsspectroscopicdatawiththoseof2reportedintheliteratures.FurthermorenewconvenienttotalsynthesismethodsofB-ring-homo-tonghaosuwerealsodevelopedtoconfirmitsstructureandmakeitsfurtherapplicationincropprotectionavailable.Inaddition,extensivecomparisonofspectroscopicdatashowedthatthestructureofcompound21reportedinliteratureshouldberevisedto2.
简介:在这份报纸,我们在公制的Lp(R)(1p)得到平均-B宽度和Sobolev班Brp(R)的无限的维的-G宽度的准确价值并且获得准确(N)和强壮的asymptotic(>1)在公制的Lq的Sobolev牛肉熏香肠班Wrpq(R)的无限的维的-G宽度的结果在公制的Lqp(R)(1qp)的(R)和它的双盒子Wrp(R)。
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简介:Thehybridstructuresofpolystyrene-b-poly(ethyleneoxide)(PS-b-PEO)blockcopolymerandinorganicnanoparticleswithgoodstabilityandbiocompatibilityhavepotentialapplicationsindrugdeliveryandbioimaging.Sphericalco-assembliesofPS120-b-PEO318andoleylamine-cappedCdSquantumdots(QDs)areproducedsuccessfullyinthisworkbyaddingwatertoamixedcommonsolvent,suchasN,N-dimethylmethanamide(DMF)/chloroform,DMF/tetrahydrofuran(THF),orDMF/toluene.TheenergydispersiveX-ray(EDX)spectrumindicatesthatQDsarelocatedattheinterfacebetweenthecoreandshellofthesphericalco-assemblies.Theco-assemblyprocessduringwateradditionistracedbytransmissionelectronmicroscopy(TEM)andturbiditymeasurement.Sphericalco-assembliesareformedthroughbuddingfrombilayersoftheblockcopolymerandQDs.Themorphologyoftheco-assembliesisrelatedtothemiscibilityoftheQD-dispersingsolventswithwaterandthemorphologychangesfromasphericaltoavesicle-likestructurewithDMF/toluene.IncreasingTHFcontentinthemixedsolventcausesmorphologicaltransitionsfromsphericalco-assembliestomulti-branchedcylindersandmicelleswhereQDsarelocatedinthecentralcore.Increasingchloroformcontentyieldsvesicle-likestructureswithprotrudingrodsonthesurface.Themechanismofthemorphologicaltransitionsisalsodiscussedindetail.
简介:Arealn×nsymmetricmatrixX=(x_(ij))_(n×n)iscalledabisymmetricmatrixifx_(ij)=x_(n+1-j,n+1-i).Basedontheprojectiontheorem,thecanonicalcorrelationde-compositionandthegeneralizedsingularvaluedecomposition,amethodusefulforfindingtheleast-squaressolutionsofthematrixequationA~TXA=Boverbisymmetricmatricesisproposed.Theexpressionoftheleast-squaressolutionsisgiven.Moreover,inthecorrespondingsolutionset,theoptimalapproximatesolutiontoagivenmatrixisalsoderived.Anumericalalgorithmforfindingtheoptimalapproximatesolutionisalsodescribed.