简介:.Thesingle2dilationorthogonalwaveletmultipliersinonedimensionalcaseandsingleA-dilation(whereAisanyexpansivematrixwithintegerentriesand|detA|=2)waveletmultipliersinhighdimensionalcasewerecompletelycharacterizedbytheWutamConsortium(1998)andZ.Y.Li,etal.(2010).Butthereexistnomoreresultsonorthogonalmultivariatewaveletmatrixmultiplierscorrespondingintegerexpansivedilationmatrixwiththeabsolutevalueofdeterminantnot2inL2(R2).Inthispaper,wechoose2I2=(2002)asthedilationmatrixandconsiderthe2I2-dilationorthogonalmultivariatewaveletY={y1,y2,y3},(whichiscalledadyadicbivariatewavelet)multipliers.Wecallthe3×3matrix-valuedfunctionA(s)=[fi,j(s)]3×3,wherefi,jaremeasurablefunctions,adyadicbivariatematrixFourierwaveletmultiplieriftheinverseFouriertransformofA(s)(cy1(s),cy2(s),cy3(s))?=(bg1(s),bg2(s),bg3(s))?isadyadicbivariatewaveletwhenever(y1,y2,y3)isanydyadicbivariatewavelet.Wegivesomeconditionsfordyadicmatrixbivariatewaveletmultipliers.TheresultsextendedthatofZ.Y.LiandX.L.Shi(2011).Asanapplication,weconstructsomeusefuldyadicbivariatewaveletsbyusingdyadicFouriermatrixwaveletmultipliersandusethemtoimagedenoising.
简介:Aseriesofoxygenpermeabledual-phasecompositeoxides60wt%Ce0.8Gd0.2O2-δ-40wt%LnBaCo2O5+δ(CGO-LBCO,Ln=La,Pr,Nd,Sm,GdandY)weresynthesizedthroughasol-gelrouteandeffectsoftheLn3+cationsontheirphasestructure,oxygenpermeabilityandchemicalstabilityagainstCO2wereinvestigatedsystemicallybyXRD,SEM,TG-DSCandoxygenpermeationexperiments.XRDpatternsrevealthatthelargerLn3+cations(La3+,Pr3+andNd3+)successfullystabilizedthedouble-layeredperovskitestructureofsinteredLBCO,whilethesmallerones(Sm3+,Gd3+,andY3+)resultedinthepartialdecompositionofLBCOwithsomeimpuritiesformed.CGO-PBCOyieldsthehighestoxygenpermeationflux,reaching2.8×10-7mols-1cm-2at925?Cwith1mmthicknessunderair/Hegradient.TheTG-DSCprofilesin20mol%CO2/N2andoxygenpermeabilityexperimentswithCO2assweepgasshowthatCGO-YBCOdemonstratesthebestchemicalstabilityagainstCO2,possiblyduetoitsminimumbasicity.ThestableoxygenpermeationfluxofCGO-YBCOunderCO2atmosphererevealsitspotentialapplicationintheoxy-fuelcombustionrouteforCO2capture.
简介:圆圆的两块面包夹上鸡肉或者牛肉,这才算是汉堡包吗?不。最近,巴黎的两位艺术家做了一种有创意的尝试。他们不仅在两块面包之间塞进了各式各样的食物,还让它们有了故事。如果把这些色彩艳丽、造型独特的汉堡包捧在手里,也许,你还真不知道该从哪儿下口呢.
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:IntheinterlayerexpansionofthelayeredzeoliteprecursorCOK-5,aSn,salt,bis(2,4-pentanedionate)-dichlorotin[Sn(acac)2Cl2],insteadofasilylatingagentwasusedtolinkthelayersat180°C.Theobtainedmaterial,whichisdesignedasSn-COE-5,showsashiftofthefirstXRDreflection,whichisverysimilartothatofCOK-5interlayerexpandedwithdichlorodimethylsilane(DCDMS),indicatinganincreaseininterlayerdistance.X-raydiffraction(XRD),N2sorptionisotherms,inductivelycoupledplasma(ICP),andX-rayphotoelectronspectroscopy(XPS)supporttheincorporationofisolatedSnsitesinthesample.Intheconversionofglucosetolevulinicacid,Sn-COE-5exhibitsmuchhigheractivitythanCOK-5,whichisduetothepresenceofLewisacidicsitesintheSn-COE-5.
简介:摘要采用溶胶-凝胶法制备了Al2O3-ZrO2复合溶胶膜,研究了化学组成和添加剂对复合溶胶的影响。结果表明,当Al2O3/ZrO2=1,DMF=40vol%时,可得到澄清透明,粘度适中,稳定性好,且凝胶干燥后几乎无开裂的溶胶膜