简介:Anewmethodisdescribedfortheelectrolessdepositionofcopperontoglass.Commerciallyavailableglassslidewasmodifiedwithγ-aminopropyltrimethoxysilanetoformself-assembledmonolayer(SAM)onit.ThenitwasdippeddirectlyintoPdCl2solutioninsteadoftheconventionalSnCl2sensitizationfollowedbyPdCl2activation.ExperimentalresultsshowedthatthePd^2+ionsfromPdCl2solutionwerecoordinatedtotheaminogroupsontheglasssurfaceresultingintheformationofN-Pdcomplex.Inanelectrolesscopperbathcontaininaformaldehydereducingagent,theN-PdcomplexeswerereducedtoPd^0atoms,whichthenactedascatalystsandinitiatedthedepositionofcoppermetal.AlthoughthecopperdepositionrateonSAM-modifiedglasswasslowatthebeginning,itreachedtothatofconventionalmethodinabout5min.
简介:Asequentialstatisticalapproachwasappliedtooptimizingthefermentationmediumofepothilones(Epos)productionbymeansofamutantwhichwasobtainedbytreatingpolyangiumcellulosumATCC15384withnitriteandultraviolet.Theeffectsofdifferentcarbonsourcesandnitrogensourcesonthefermentationmediumweretested,andthesuitableoneswereselected.Thenauniformdesignwasemployedtodesigntheexperiments.Alinearmodelwasdevelopedforidentifyingthesignificantcomponentsinfermentationmedium,whileathirddegreepolynomialmodelwasusedforstudyingtherelationshipbetweentheconcentrationofthecomponentsinfermentationmediumandtheyieldofEpos(YEPs).Apatternsearchmethodwasusedforsearchingtheoptimumfermentationmediuminthetestspace,whichwasasfollows(g/L):potassiumnitrate8.00,soybeanpeptone17.60,potassiumhydrogenphosphate1.00,beefextraction6.46,yeastextraction1.00,calciumchloride0.25,sodiumchloride1.00andferricchloride0.02.TheoptimumfermentationmediumwasexpectedtoresultinayieldofEpos(YEPs)of2.48mg/L.ThevalidationexperimentswiththeoptimummediumwereperformedintriplicateandtheaverageyieldofEposwas2.45mg/Lwhichwas7.78timeshigherthanthatofEpospreparedwithoutoptimization.
简介:Aflexibleapproachtoethyl(3R,4S)-N-Boc-4-amino-3-hydroxy-5-phenylpentanoate(N-Boc-AHPPA-OEt),theγ-amino-β-hydroxyacidmoietyofhapalosinisdescribed.Thesyntheticmethodfeaturesaring-openingethanolysisofanactivatedN-Boc-lactam,whichisobtainedviaadiastereoselectivereductive-alkylationof(R)-malimidederivative.TheflexibilityofthemethodresidesintheintroductionofthealkylsidechainbyGrignardreagentaddition.
简介:Auniversalsimulatorcapableofsimulatingvirtuallyanyuser-definedelectrochemical/chemicalproblemsinone-dimensionaldiffusiongeometrywasdevelopedbasedonanexponentiallyexpandinggridmodificationoftheexistingnetworkapproach.Somegeneralizedreaction-diffusiongoverningequationsofanarbitraryelectrochemical/chemicalprocesswerederived,andprogramcontrolledautomaticgenerationofthecorrespondingPSPICEnetlistfilewasrealized.Onthebasisoftheabovetechniques,auniversalsimulatorpackagewasrealized,whichiscapableofdealingwitharbitrarilycomplexelectrochemical/chemicalproblemswithone-dimensionaldiffusiongeometrysuchasplanardiffusion,sphericaldiffusion,cylindricaldiffusionandrotationaldiskdiffusion-convectionprocesses.Thebuildingofsuchasimulatoriseasyandthusitwouldbeveryconvenienttohaveitupdatedforsimulationsofnewlyraisedelectrochemicalproblems.
简介:Ring-closingmetathesisreactionsinvolvingdiallyldiphenylsilaneanddiallyloxydiphenylsilaneweresuccessfullyperformedbyusingonly0.01molorevenlessofGrubbscatalyst1.Theeffectsofreactionparameters,suchassolvents,temperatureandconcentrationofthecatalystarediscussed.
简介:
简介:Bothenantiomersoffluoxetineweresynthesizedinfivestepsfromethylbenzoylacetate(1)usingmicrobial-chemicalapproachwithoverallyieldsof59%and62%respectively.(S)-Enan-tiomercanbeobtainedin>99%e.e.byrestingcellofbaker’syeastandtheRformwasproducedin81%e.e.byimmobilizedGeotrichumsp.G38.
简介:Theexponentiallyexpandedspacegridwasincorporatedintothenetworkapproachtoovercometheproblemoflowsimulationefficiencyduringthesimulationsofelectrochemicalproblemswithstiffkineticsorwidedlsperslonofdiffusioncoefficients,resultinginaneffectiveelectrochemicalsimulationmethod:exponentiallyexpandedgridnetworkapproach(EEG-NA).ThestabilityandaccuracyoftheEEGNAforthesimulationofvariouselectrodeprocesses.coupledwithdifferenttypesofhomogeneousreactionswereinvestigated.
简介:
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:采用油的酸的一条简单solvothermal途径被开发了与不同形状准备锐钛矿TiO2nanocrystals,它被从0~0.5mmol增加NaF的数量从nanorods调节到nano椭圆体,并且光乐队差距因此从3.47eV减少了到3.29eV。不管多么当氟化物被改变到NH4F,结果的TiO2nanocrystals拥有了一个锐钛矿阶段,但是由小尺寸的nanocrystals组成并且nanorods,和乐队差距被增加到3.53eV。X光检查光电子光谱学(XPS)结果与NaF的增加的数量说明了氟的符号内容的增加为形状和光乐队的变化的报道能TiO2nanocrystals豁开。而且,氟的符号内容的缺席引起了形状的更少的变化,产品的光乐队差距的增加面对NH4F。这结果可以提供另一个方法与氟化物的帮助改变形状和金属氧化物nanocrystals的乐队差距。