简介:Theelectrochemicaloxidationofdiphenylamineinacetonitrileproducesanadherentuniformpolymerfilmwhichexhibitsmutiplecolourvariation(yellow-green-blue)inawiderangeofpotentialscan.Thepolymerizationmechanismandthestructureofthepolymerwerestudiedbycyclicvoltammetry,FT-IRandinsituESR.Theresultsindicatethattheelectrochemicalpolymerizationofdiphenylaminebelongstoacationicradicalpolymerizationprocess.Duringelectrolysis,onlyoligomerswereinitialyproduced,thenpolymerfilmwasformedontheelectrodesurface.Theelectropolymerizationperformsviathe4,4’C-Cphenyl-phenylcouplingmechanism.
简介:ThesurfacecompositionandelectronicstructureoftungstencarbidespreparedbydirectsynthesisandcarburizationofwhitetungsticacidwerestudiedwithX-rayphotoelectronspectros-copy.TheexperimentalresultsshowthatWO3andfreecarbonarepresentonthesurfaceofthecarbides.Forthehighsurfaceareatungstencarbidepreparedfromwhitetungsticacidalargeextentofoxygeninsertionintothecrystallatticewasobserved.MeasurementsofthebindingenergiesoftheW47/2,C1sandO1scorelevelsindicatethatchargetransferisfromtheWtotheCandOatoms,formingW5d-C2pandW5d-O2pbonding.ThecatalyticbehaviorofthetungstencarbidesinhydrocarbonconversionreactionsismentionedandcomparedwithPtcatalysts.
简介:[1]BASFUSP4479906[2]BASFBP1443541[3]BASFDE3618265[4]WangL.,WuZ.,ChinaLeather,26(8),11,(1997)[5]YuanL.,DinY.,ChineseChemistryBulletin,(2),19(1988)[6]KurokiH.,ChemistryofDyeingTheory(ChineseTranslation),TextileIndustryPress,Beijing,89(1982)[7]WangS.,LiP.,WuZ.DyestuffIndustry(Chinese),34(4),1,(1997)[8]Tian,Y.,Wu,Z.,Wang,G.,Zhang,S.J.ChineseChem.Eng.,46,156(1995)[9]Tian,Y.,Wang,G.,Wu,Z.,J.ChineseChem.Eng.,47,75(1996)[10]Lycka,A.,DyesandPigment,32,11(1996)[11]Griffith,J.,ColourandConstitutionofOrganicMolecules,AcademicPress,London,191(1976)
简介:Ringinversionofeightsubstituted2-phenyl-4,4-dimethyloxazolidinesino-dichloro-benzene-d4wasstudiedbyHDNMR.Veryhighinversionbarriers(/nGc/n=86.7—93.4kJ·mol-1)werefoundfortheseoxazolidinerings.Themagnitudeoftheinversionbarrierisdependentonthepolarityofthesubstituentonthephenylgroup.Alinearcorrelationispresentbetweenthe/nGc/noftheinversionandthesubstituentconstant,σ+,ofthesubstituent.
简介:Phosphatdylcholinesandtheiranalogs,thefunctionalbuildingblockofthemembrane,arerecentlyfoundtomediatemultiplephysiologicalprocessesandexhibitabroadrangeofdesirablepharmacologicaleffects,whichinvolvehydrophobiclipophilicinteractions(HLI)betweenthephospholipidandthecellmembrane.TheHLIbehaviorofphosphatJdylcholines(Ln)andtheiranalogues1,2-diacyl-sn-glycerol-3-phosphoricacidbromoethylester(Pn),havebeeninvestigatedinMeOH-H20binarysystemsofdifferentvolumefractions(designatedasΦ)oftheorganiccomponent,byemployingα-nephthylethyllaurylether(Np-12)asfluorescentprobe.AveryinterestingobservationisthattheLnpossessesdoublecharacter,i.e.,itbehavesbothasanaggregatorandasadeaggregator.Theeffectsofthestructureandtheenvironmentonthecoaggregationanddeaggregtionarealsodiscussed.
简介:Experimentaldataofhydrolyticpolymerizationoflanthanideionsinaqueoussolutionweretreatedbygraphicmethod,computerfittingandpqanalysis,speciespresentwereascertainedandhydrolysisconstantsobtained.Ln(OH)2+andLn2(OH)24+predominatedinthespeciesofallhydroly-sisproducts.Whenthefirstandthesecondhydrolysisconstantswereplottedagainstradiiandef-fectivenuclearchargeoflanthanideions,thecurvesobtainedconformedwiththe“three-divisiongroups”rule.CorrelationbetweenhydrolysisconstantsofLn2(OH)24+andotherhydrolysisconstantsislinear.Usingtheaboveempiricalcorrelationswecalculatedhydrolysisconstantsofalllanthanideionsandobtainedsatisfactoryresultswhichshowedgoodregularityforhydrolysisoflanthanideionsandthussystematizedalldataofthereaction.
简介:在allosteric酶和底层之间的有约束力的过程上的使活跃之物分子和压抑的分子的效果被考虑绑在allosteric酶的调整分子的heterotropic效果讨论。有heterotropic效果的allosteric酶的一个模型被介绍。在规定过程的cooperativity和anticooperativity被学习。
简介:Theinfraredmulti-photondissociation(IRMPD)ofaceticanhydridetogeneratestate-selectedCH2hasbeeninvestigatedbyusingtimeandwavelengthresolvedfluorescencetechniques.IthasbeenobservedthatthegenerationofthenascentgroundstateCH2(a1A1)isdelayedbyabout0.6μsrelativetotheonsettimeoftheexcitedCH2(b1B1).TherelativepopulationofthegroundandexcitedstateCH2andtheonsettimefortheappearanceofthegroundstateCH2havebeenfoundtodependstronglyonCO2laseroutputfluences.TheseresultsappeartohaveastrongbearingonthestructureofthepotentialenergysurfacesoftheintermediateCH2CO.Apossiblephotolysisme-chanismisproposedtoexplaintheseexperimentalresults.
简介:TheNMRmethods(including1HNMR,13CNMR,variabletemperaturemethodandthenovel1DEXSYtechnique)wereemployedtostudytheconformationofazacrownethers1-5insolution.Therearetwoclassesofconformationinwhichtheazacrownethersexistinsolutionac-cordingtotheirmolecularstructure.Twokindsofintramolecularmotionoftheazacrownetherswereobserved,oneisthevibrationofthemacrocyclicringandtheotherisitsinversion.TheetherringswhichcontainoxygensaremoreflexiblethanthatconstructedbynitrogensinthepresentcasebecauseofthetetrahedronstructureofthenitrogenatomsandthehindranceofthegroupsTsconnectedtothenitrogens.Somethermodynamicalparametersoftheringinversionprocesswereobtained.
简介:Vesiclecanbepreparedfromaqueousmixturesofsimplecommerciallyavailable,single-tailedcanonicandanionicsurfactants.Inthiswork,theI3/I1value,Ie/Imvalue,andfluorescencelifetimeofpyreneindifferentsystems(seethepreparationofsamples)weredetermined.Hieessentialaffectingfactorsintheformationofvesiclecanbededucedfromtheobtainedresults.Itshowedthatlargevesiclemustformnaturallybeforesonicationin0.082MoctyltrimethylammoniumbromideandsodiumlauratepH=9.2aqueoussolution.Whileaftersonication,onlysmallvesicleexists,whichcanbeprovedfurtherthroughelectronmicroscope.
简介:TwopossiblereactionmechanismsofVS~+(~3∑~-,~1Γ)withCOinthegasphasehavebeenstudiedbyusingB3LYP/TZVPandCCSD(T)/6-311+G(3dr,3pd)methods:theO/Sexchangereaction(VS~++CO→VO~++CS)andtheS-transferreaction(VS~++CO→V~++COS).Thetworeactionsproceedviatwo-stepandone-stepmechanism,respectively.ThebarriersofthetripletandsingletPESsare30.6and50.9kcal/mol,respectively,forO/Sexchangereactionand7.3and50.2kcal/mol,respectively,fortheS-transferreaction.Theresultsindicatethatthetripletgroundstatereactionismorefavorable,andtheS-transferreactionismorefavorablethantheO/Sexchangereaction,whichisingoodagreementwiththeexperimentalobservation.
简介:TheinfluenceofthesurfacestateofthegraphitefurnaceatomizerontheatomizationofhydrideshasbeenstudiedbymeansofsurfacefilmcoatingandquantumchemistryCN-DO/2calculations.TheresultsofthestudyprovethattheatomizationofAsH3,SbH3andBiH3inthegraphitefurnaceatomizerisnotasimplegasphasepyrolyticprocess,butasurfacecatalysispyrolyticprocess.
简介:Adetectionofanthracyclineantitumordrugdaunomycin(DNR)reactingwithDNAinsimulatemetabolisminvitrohasbeenmade.ItwasfoundthatDNRcouldreactwithDNAtoformDNR-DNAadducts.TheadductcompositionsofDNRwithfishspermDNAandthermallydenaturatedDNAweredetermined.TheequilibriumassociationconstantKofDNRwithfishspermDNAis1.98×10^5L/molandthatofDNRwithdenaturatedDNAis2.29×10^4L/mol.Semiquinonefreeradicals,metabolicproductsofDNR,candestroybothfishspermDNAanditsthermallydenaturatedDNA.ItisverifiedbyhyperchromiceffectincreaseobservedinUVspectrumandAFMexperiments.ThemechanismofDNAdegradationhasalsobeeninvestigated.Resultsobtainedallowonetoexplainthereasonofsideeffectofanthracyclinedrugandgivethewaytodepress,whichwereofclinicalsignificance.
简介:AvohammetricstudyoftheinteractionofneutralRed(NR)withDNAatagoldelectrodeinaphosphatebuffersolutionisdescribed.AfteraddingDNAinanNRsolution,thereductionpeakcurrentofNRdecreases.ThebindingmeehahismsofNRtoDNAindifferentpHrangesaredifferent.ThereductionpeakpotentialofNRinapH7.0phosphatebuffersolutioninthepresenceofDNAshiftspositively,indicatingthatthebindingofNRtoDNAisintercalationaction,butatpH=6.0thereductionpeakpotentialofNRshiftsnegatively,indicatingthatthebindingofNRtoDNAiselectrostaticaction.TheformedcomplexesareDNA-NRwhen[NR]/[DNA]<0.18andDNA-3NRwhen[NR]/[DNA]>0.35,respectively.
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简介:为单个核苷酸多型性(SNP)的当前的方法分析消费aretime并且复杂。我们为快速的SNP分析在一步舞的开发瞄准了即时fluorescencemutant-allele-specific扩大(MASA)方法。方法是二种技术的婚姻:为目标脱氧核糖核酸和双stranded的MASA教材DNA选择的荧光染料,格林·西布尔I.Genotypes根据thewild类型的不同阀值周期被分开,变异的primers.K地岬oncogene被用作一个目标验证不同遗传型能清楚地是,这试金区别的试验性的结果显示出的themethod.The的可行性。即时荧光MASA方法将由于它的简洁和低费用为快、可靠的SNP分析有一个庞大的潜力。
简介:Theacylationof3-pentanoneenaminewasstudiedandanovelformationof4-pyronesfromβ-diketoneenolesterswasfoundinvolvinganintramolecularO-toC-acylshiftfollowedbycyclization.