简介：Inthiswork,theinfluenceofCO2onthestructuralvariationandcatalyticperformanceofNa2WO4/Mn/SiO2foroxidativecouplingofmethanetoethylenewasinvestigated.ThecatalystwaspreparedbyimpregnationmethodandcharacterizedbyXRD,RamanandXPStechniques.AppropriateamountofCO2inthereactantgasesenhancedtheformationofsurfacetetrahedralNa2WO4speciesandpromotedthemigrationofOinMOx,Na,Wfromthecatalystbulktosurface,whichwerefavorableforoxidativecouplingofmethane.WhenthemolarratioofCH4/O2/CO2was3/1/2,enrichedsurfacetetrahedralNa2WO4speciesandhighsurfaceconcentrationofOinMOx,Na,Wweredetected,andthenhighCH4conversionof33.1%andhighC2H4selectivityof56.2%wereobtained.WithfurtherincreaseofCO2inthereagentgases,thecontentofactivesurfacetetrahedralNa2WO4speciesandsurfaceconcentrationofOinMOx,Na,Wdecreased,whilethatofinactivespecies(MnWO4andMn2O3)increaseddramatically,leadingtolowCH4conversionandlowC2H4selectivity.ItcouldbespeculatedthatNa2WO4crystalwastransformedintoMnWO4crystalwithexcessiveCO2addedunderthereactionconditions.PretreatmentofNa2WO4/Mn/SiO2catalystbymoderateamountofCO2beforeOCMalsopromotedtheformationofNa2WO4species.
简介：Thetitlecomplex,[La(baec)1/2(H2btec)1/2(H2O)]n(H4btec=1,2,4,5-benzenetetracarboxylicacid)(1)wassynthesizedbythehydrothermalreactionof1,2,4,5-benzenetetracarboxylicdianhydridewithLa(NO3)3·6H2OinH2O,andcrystallizesinthetriclinicsystem,spacegroupP-1withα=0.64403(3)nm,b=0.94500(4)nm,c=0.96380(5)nm,α=88.535(2)°,β=100.314(2)°,γ=76.6470(10)°,V=1.69968(10)nm^3,Z=2,andfinalR=0.0274,Rw=0.0735.In1,eachLa(Ⅲ）ioniscoordinatedbyeightoxygenatomsfromsixcarboxylategroupsandonecoordinatedwatermolecule.TwodifferentcoordinstionmodesofH4btecwerePresentinthestructure,oneofwhichcontainstwoprotonatedcarboxylategrougpstobalancethecharge.
简介：Halfsandwichirondicarbonylcomplex[η5-C5H3(t-Bu)2]Fe(CO)2Cl(1)reactswith1,2-dilithiumdiselenocarboraneLi2Se2C2B10H10(2)togiveabinuclearironcarboranecomplex[η5-C5H3(t-Bu)2]2Fe2(CO)3*Se2C2B10H10(3).TheX-raydiffractionanalysisofcomplex3revealsthatoneoftheironatomsischiral.
简介：TostudytheintramolecularDiels-Aldercycloadditonof2H-chromen-2-oneasadiene,aseriesofchiralN-allyl-N-benzylamidesthatcontaina2H-chromen-2-onemoietyweredesignedforthesynthesisofbenzo[f]isoindol-l-onesviaanintramolecularDiels-Alderandasubsequentretro-Diels-AldercycloadditionwiththeexpulsionofCO2.Boththeyield（80%-89%）andabsolutestereocontrolofthetandemreactionwerehighwhenanelectron-withdrawinggroupwasattachedtothedienophile.Thedoublebondinthestyrenesubstructureremainedintheproductscouldbefurtherderivatizedbydihydroxylation.
简介：Three-dimensional(3D)flowerlikehierarchicalZn2GeO4andMn2+-dopedZn2GeO4microstructureshavebeenpreparedbyafacilehydrothermalapproach.X-Raydiffraction(XRD),fieldemissionscanningelectronmicro-scopy(FESEM),transmissionelectronmicroscopy(TEM)andphotoluminescence(PL)spectrometrywereemployedtocharacterizethesamples.SuchflowerlikehierarchicalZn2GeO4microstructureswithanaveragediameterof3―4μmwerefoundtobeconstructedbyabundantsinglecrystallinenanorodsofabout90nmindiameter.TheluminescentpropertiesofZn2GeO4:xMnphosphorswithdifferentcontentsofMn2+asanactivatorwereinvestigated.TheMn2+-dopedsamplesshowedgreenluminescencecorrespondingtothed-dtransitionofMn2+undertheirradiationofUVlight.Theredshift(from531nmto538nm)inλemwithincreasingMn2+contentwasobservedintheluminescentspectra,whichshouldbeattributedtoaweakcrystalfieldbecauseofthesubstitutionofZn2+byMn2+atadistortedtetrahedrallatticesite.
简介：Asimplemethodisappliedtocalculatingtheisotopeshifts(ISs)on5S1/2→4D3/2,5/2transitionsof87,88Sr+.FirstwehavecalculatedtheISsoflowertransitionsonaseriesofalkali-likesystemssuchasB2+,Ca+andBa+,whichareinagreementwithotherworks.ThentheISson5S1/2→4D3/2,5/2transitionsof87,88Sr+,whichareusefultostudytheSr+opticalfrequencystandard,areevaluated.
简介：AseriesofTiO2-XSiO2[Xdenotesthemolarfraction(%)ofsilicainthemixedoxides]withdifferentn(Ti)/n(Si)ratioswaspreparedwithammoniawaterasahydrolysiscatalyst.ThephotocatalystspreparedwerecharacterizedbyXRD,thermalanalysis,FTIR,UV-VisandSPS.ThecharacterizationresultsofFTIRandUV-VisspectrashowthatTiatomsweregraduallychangedfromoctahedralcoordinationtotetrahedralcoordinationwiththeadditionofsilica,whichisnotbeneficialforobtainingstrongBrnstedacidityandhigherphotocatalyticactivity.Thephotocatalyticactivityexperiments,whichwereconductedbyusingheptane(orSO2)asthemodelreactant,showedthatTiO2-SiO2containingasuitableamountofsilicacanexhibitmuchhigherphotocatalyticactivitythanpureTiO2.Theenhancedphotocatalyticactivitycanbeattributedtothreefollowingfactors:(1)smallercrystallinesize;(2)higherthermalstability;(3)thenewstrongBrnstedacidity.
简介：ＣａｒｂｏｎｙｌａｔｉｏｎｏｆＡｌｌｙｌＣｈｌｏｒｉｄｅＣａｔａｌｙｚｅｄｂｙＰｄＣｌ２（ＴＰＰＴＳ）２ｉｎＴｗｏ－ｐｈａｓｅＭｅｄｉｕｍＣａｒｂｏｎｙｌａｔｉｏｎｏｆＡｌｌｙｌＣｈｌｏｒｉｄｅＣａｔａｌｙｚｅｄｂｙＰｄＣｌ２（ＴＰＰＴＳ）２ｉｎ...
简介：ForquadraticnumberfieldsF=Q(√2pl…pt-1)withprimespj≡1mod8,theauthorsstudytheclassnumberandthenormofthefundamentalunitofF.TheresultsgeneralizenicelywhathasbeenfamiliarforthefieldsQ(√2p)withaprimep≡1mod8,includingdensitystatements.Andtheresultsarestatedintermsofthequadraticformx2+32y2andillustratedintermsofgraphs.
简介：Takingadvantageofthelargeγ-detectorarrayGammasphereandtherecoilmassseparatorFMA,highspinstatesin117Bawereinvestigatedthroughtherecoil-β-delayedprotondecaytaggingtechniqueviatheheavy-ioninducedfusion-evaporationreaction64Zn(58Ni,2p3n)117Ba,atabeamenergyof305MeV.Promptγraysbelongingto117Bahavebeenidentifiedfurthermore,arotationalbandhasbeenidentifiedforthefirsttimeandpresentedasbandAinFig.1.
简介：Anewmethodforfabricatingorderedporoussiliconisreported.Atwo-dimensionalsilicananospherearrayisusedasatemplatewithahydrofluoricacid-hydrogenperoxidesolutionforetchingthenanospheres.Theinitialdiameteranddistributionoftheholesintheresultingporoussiliconlayeraredeterminedbythesizeanddistributionofthesilicananospheres.Thecorrosiontimecanbeusedtocontrolthedepthsoftheholes.ItisfoundthatthepresenceofaSiO_2layer,formedbytheoxidationoftheroughinternalsurfaceofthehole,istheprimaryreasonallowingthecorrosiontoproceed.Ultravioletreflectionandthermalconductivitymeasurementsshowthatthediameteranddistributionoftheholeshaveagreatinfluenceonpropertiesoftheporoussilicon.
简介：ElectrolyticfixationofCO2wasinvestigatedbyelectrocarboxylationoforganichalides(RX),andfourestersⅠ,ⅡⅢ,Ⅳ)wereobtainedinmoderateyields.ElectrochemicalreductionesterificationsofRXinthepresenceofCO2werecarriedoutonnanocry'stallineTiO2-Ptelectrode.TheelectrochemicalbehaviorofRXinthepresenceofCO2wasinvestigatedbythetechniqueofcyclicvoltammetry,andtheprobablereactionmechanismw,asproposed.
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