简介:Asimplelayer-by-layerdepositiontechniquewasusedtofabricatethemultilayerthinfilmsofunmodifiedsilvertriangularnanoplates(AgTNPs).ThemultilayerofAgTNPsthinfilmswerefabricatedbyalternatedepositionofeachanionicsodiumcitratestabilizedAgTNPsandcationicpoly(diallyldimethylammoniumchloride).AllpreparedAgTNPsmultilayerthinfilmswereexhibitedastrongplasmonbandatthewavelengthof667nm,whichconfirmedtheformationofAgTNPsontothesubstrate.Thecharacteristicsofthemultilayerthinfilmswereinvestigatedusingcontactanglemeasurement,UV-visiblespectroscopy,X-raydiffractionanalysis(XRD),atomicforcemicroscope(AFM)andfieldemissionscanningelectronmicroscope(FESEM).Asthesefilmsaretobeusedasamercury(II)colorimetricsensor,thechangesinopticalpropertiesofthefilmswereevaluatedforvariousmercury(Ⅱ)concentrations.AgTNPsassembledintothinfilmsshowedastrongcolorshiftfrombluetomauveandcolorlesswhenexposedtomercury(Ⅱ).Theconstructedmultilayerthinfilmsexhibitedexcellentcolorchangesofmercury(II)withalinearrangebetween0.5and20ppm.Thelimitofdetection(LOD)andlimitofquantitation(LOQ)were0.45±0.002and1.52±0.002ppm,respectively.TherecoveryvaluesofAgTNPsmultilayerthinfilmsaresatisfactoryintherangeof100.1%-106.4%whenappliedtodeterminingmercury(Ⅱ)inwatersamples.
简介:Amild,regioselective1,3-dipolarcycloadditionprotocolforthepreparationofphenylselenomethylisoxazolinesthroughsubstitutedallylphenylselenidesandnitrileoxideswasreported.
简介:Activatedcarbons(ACs)withawiderangeofsurfaceareasweremadefrompetroleumcokebymeansofKOHactivation.Theelectrochemicalcharacterizationwascarriedoutforseveralactivatedcarbonsusedaspolarizableelectrodesofelectricdouble-layercapacitors(EDLCs)inanaqueouselectrolyticsolution.Theporousstructuresandelectrochemicaldouble-layercapacitanceoftheactivatedcarbonswereinvestigatedbyvirtueofnitrogengasadsorptionandconstantcurrentcycling(CCC)methods.Therelationshipamongthesurfacearea.porevolumeoftheactivatedcarbonsandspecificdouble-layercapacitancewasdiscussed.ItwasfoundthatthespecificcapacitanceofACsincreasedlinearlywiththeincreaseofsurfacearea.Thepresenceofmesoporesintheactivatedcarbonswithveryhighsurfacearea(>2000m^2/g)wasnotveryeffectiveforthemtobeusedasEDLCs.Theinfluenceofchemicalcharacteristicsoftheactivatedcarbonsonthedoublelayerformationcouldbeconsideredtobenegligible.
简介:Three—layerback—propagationneuralnetworkswereusedforprocessingtheinformationprovidedbytheultravioletspectraoffive—componentmixtures,affectingthesimultaneousdeterminationofthecomponentswithsatisfactoryresults.
简介:NucleosideisthemainclassofactivecomponentsinCordycepssinensis.Thin-layerchromatography(TLC)isoneofthemostcommonlyusedmethodsinpharmacopoeiasforanalyzingchemicalcomponentsofherbalmedicine.SincetheisocraticelutionmethodcannotbeappliedsuccessfullyinTLCanalysisforseparatingallthenucleosidecomponents,thestepwisegradientelutionhasbeendevelopedinthisworktoseparateeightnucleosidestandardswithsuccess.Inthisway,quantitativeanalysesofthesamplesofCordycepssinensiswereachievedviatheproposedTLCprocedurecoupledwiththescanningdensitometrictechniquesofCAMAGandTLCQAmethodsforqualitativeandquantitativeanalysis.
简介:Poly(vinylidenefluoride)(PVDF)/multi-walledcarbonnanotube(MWCNT)nanocompositeswerepreparedbymeansofultrasonicdispersionmethod.X-raydiffraction(XRD)resultsindicatethatincorporatingMWCNTsintoPVDFcausedtheformationofβphase.Athermalannealingat130°Cconfirmedthattheβphasewasstableinthenanocomposites.Differentialscanningcalorimetry(DSC)resultsindicatethatthemeltingtemperatureslightlyincreasedwhiletheheatoffusionmarkedlydecreasedwithincreasingMWCNTcontent.ThetensilestrengthandmodulusofPVDFwereimprovedbyloadingtheMWCNTs.Thescanningelectronmicroscopy(SEM)observationsshowedthatMWCNTswereuniformlydispersedinthePVDFmatrixandaninterfacialadhesionbetweenMWCNTandPVDFwasachieved,whichwasresponsiblefortheenhancementinthetensilestrengthandmodulusofPVDF.
简介:Polyamide/acrylonitrile-butadiene-styrenecopolymer(PA/ABS)blendshavedrawnconsiderableattentionfrombothacademiaandindustryfortheirimportantapplicationsinautomotiveandelectronicareas.DuetopoormiscibilityofPAandABS,developinganeffectivecompatibilizationstrategyhasbeenanurgentchallengetoachieveprominentmechanicalproperties.Inthisstudy,wecreateasetofmechanicallyenhancedPA6/ABSblendsusingtwomulti-monomermelt-graftedcompatibilizers,SEBSg-(MAH-co-St)andABS-g-(MAH-co-St).Thedisperseddomainsizeissignificantlydecreasedandmeanwhiletheunique“softshell-encapsulating-hardcore”structuresforminthepresenceofcompatibilizers.Theoptimummechanicalperformancesmanifestanincreaseof36%intensilestrengthandanincreaseof1300%inimpactstrength,comparedwiththeneatPA6/ABSbinaryblend.
简介:Inthisworkamulti-objectivequantitativestructure-propertyrelationship(QSPR)analysisapproachwasreportedbasedonthestudyonthreepartitionpropertiesof50aromaticsulfur-containingcarboxylates.Heremulti-objectives(properties)weretakenasavectorforQSPRmodeling.Thequantitativecorrelationsforpartitionpropertiesweredevelopedusingage-neticalgorithm-basedvariable-selectionapproachwithquantumdescriptors,derivedfromAM1-basedcalculations.WiththeQSPRmodels,theaqueoussolubmty,octanol/waterpartitioncoefficientsandreversed-phaseHPLCcapacityfactorsofsulfur-contalningcompoundswereestimatedandpredicted.UsingGA-basedmultivariatelinearregressionwithcross-vali-dationprocedure,asetofthemostpromisingdescriptorswasselegtedfromapoolof28quantumchemicalsemi-empiricalde-scriptors,inclodingstericandelectronictypes,tointegrallybuildQSPRmodels.Theselectedmoleculardescriptorsinclud-edthenetchargesoncarboxylgroup(Qoc),the2ndpowerofnetehnrgesonnitrogenatoms(QN^2),thenetatomicchargeonthesulfuratoms(Qs),thevanderWaalsvolumeofmolecule(V),themostpositivenetatomicchargeonhydrogenatoms(QH)andthemeasureofpolarityandpolarizability(π),whichweremainfactorsaffectingthedistributionprocessesofthecompoundsunderstudy.ThestatisticallybestQSPRmodelsofsixdescriptorsweresimultaneouslyobtainedbyGA-basedlinearregressionanalysis.WiththeselecteddescriptorsandtheQSPRequations,mechanismsofpartitionactionoftheSulfur-containingcarboxylateswereabletobeinvestigatedandinter-preted.
简介:Inthiswork,acidfunctionalizedmulti-wallcarbonnanotubes(MWCNTs)weremodifiedwithimidazolium-basedionicliquids.Theselectiveoxidationofvariousalcoholswithhydrogenperoxidecatalyzedby[PZnMo_2W_9O_(39)]~(5-),ZnPOM,supportedonionicliquids-modifiedwithMWCNTs,MWCNTAPIB,isreported.Thiscatalyst[ZnPOM@APIB-MWCNT],wascharacterizedbyX-raydiffraction,scanningelectronmicroscopy(SEM)andFT-IRspectroscopicmethods.Thisheterogeneouscatalystexhibitedhighstabilityandreusabilityintheoxidationreactionwithoutlossofitscatalyticperformance.
简介:Athree-dimensionalfew-layerreducedgrapheneoxide-wrappedmesoporousLi4Ti5O12(m-LTO@FLRGO)electrodeisproducedusingasimplesolutionfabricationprocess.WhentestedasananodeforLiionbatteries,them-LTO@FL-RGOcompositeexhibitsexcellentratecapabilityandsuperiorcyclelife.Thecapacityofm-LTO@FL-RGOreaches165.4mAhg-1after100cyclesbetween1and2.5Vatarateof1C.Evenatarateof30C,ahighdischargecapacityof115.1mAhg-1isstillobtained,whichisthreetimeshigherthanthepristinemesoporousLi4Ti5O12(m-LTO).Thegraphenenanosheetsareincorporatedintothem-LTOmicrosphereshomogenously,whichprovideahighconductivenetworkforelectrontransportation.
简介:Anewcompoundbasedonpolyoxovanadate[{Ni(en)2}2Sb8V14O42]·5.5H2O(en=ethylenediamine)(1)wassynthesisedhydrothermallyasblackrhombuscrystals.Compound1crystallizedinthemonoclinicsystemwithspacegroupP21/n,Z=4,a=1.46953(9)nm,b=1.28623(8)nm,c=1.76008(11)nm,β=105.7230(10)°.Intheasymmetricunit,cluster{Sb8V14O42}canbeconsideredasanSbderivativeofthe{V18O42}unit.Each{Sb8V14O42}clusterasabuildingblockinterconnectedtofourotherneighboringunitsby{Ni(en)2}bridginggroupswhicharelinkedthroughtheterminaloxygenatomsofthepolyoxoanions,formingatwodimensionalnetwork.