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简介：Eightnovelcompoundshavebeensynthesizedandtheyaretwoseriesofmixedtri（butyl/cyclohexyl）tincarboxylates:BunCy3-nSnO2CR（n=1,2;R=n-C3H7,C6H5,4-ClC6H4,4-NO2C6H4）.InadditiontothestudiesoftheirstructureswithIR,119Snand13CNMR,wetestedtheirfungicidal,insec-ticidalandacaricidalactivities.Thepercentageofinhibitiontotheaforementionedphytopathogenisabout80—100%at50ppminglasshouseand100%forT.Uriticaeat500ppm.Thosefindingsindicatethatthiskindofcompoundshavebothfungicidalandacaricidalactivitiesandmayhaveagoodprospectforapplications.

简介：

简介：Diblockcopolymerscontainingpolystyrene(PSt)andpolybutylmethacrylate(PBMA)segmentsandrandomcopolymerofstyrene(St)andbutylmethacrylate(BMA)havebeenpreparedbyatomtransferradicalpolymerization(ATRP).DiblockcopolymersofBMAandStwithpredeterminedmolecularweight(1×10^4-6.5×10^4)andnarrowermolecularweightdistribution(1.25-1.5)wereobtained.Therandomcopolymercompositionsweredeterminedby^1HNMRspectroscopyandthereactivityratioswereevaluatedbytheextendedKelen-TudosmethodtobeYSt=0.91,YBMA=0.32.

简介：OpticallypureL-butyllactatewassynthesizedbynormaltransesterificationusingnafion-Hcatalystinmoderateyield.Variousreactionconditionswereinvestigated,includingthereactiontemperature,reactiontime,ratioofthestartingmaterialandamountofthenafioncatalyst.

简介：Averymildandextremelyefficienthydrolysismethodfortransformationofpolystyrene-b-poly(tert-butylacrylate)(PS-b-PtBA)topolystyrene-b-poly(acrylicacid)(PS-b-PAA)wasdesignedandcarriedoutusingmoreconvenientandinexpensivechlorotrimethylsilane/sodiumiodideasreagents.Thehydrolysisproductcanself-assembleinaqueousmediatogiveregularmicelleswithPSblockformingthecoreandPAL4blockformingthecorona,orintetrahydrofuran(THF)togivereversemicelleswiththehydrophilicblockinthecore.

简介：Thesemibatchemulsifier-freeemulsioncopolymerizationofmethylmethacrylate(MMA)andbutylacrylate(BA)inthepresenceof2-hydroxyethylmethacrylate(HEMA)initiatedbyK2S2O8(PSP)wasstudied.Thelatexparticlescanmaintainanappreciablestabilityduringtheemulsifier-freeemulsioncopolymerizationofMMAandBAinthepresenceofHEMA.Theaverageparticlediameterincreasewithanincreaseoftotalsolidscontent,HEMAcontent,PSPcontent,ionicstrengthofthesystemandmonomerfeedrate,anddecreasewiththemonomerfeedrationfrom3/1(MMA/BA:molarration).to1/3.ThestabilityofthisreactionsystemisimprovedbyaddingHEMAasnonioniccomonomer,Highsolidscontent(50%)latexwithmonodisperseparticlecanbeobtainedusingthisprocess.

简介：ThesynthesisandphosphorescencepropertiesoftwonovelIr（Ⅲ）complexesbearingtert-butylsubstituents,bis(4-tert-butyl-2-phenylbenzothiozolato-N,C2′)iridium（Ⅲ）（acetylacetonate）[（tbt）2Ir（acac）]andbis(4-tert-butyl-1-phenyl-1H-benzimidazolato-N,C2′)iridium（Ⅲ）（acetylacetonate）[（tpbi）2Ir（acac）],arereported,theirmolecularstructuresareconfirmedby1HNMR,ESI-MSandelementaryanalysis.Photoluminescence（PL）studiesrevealedthattheycanemitstronggreenandorangephosphorescenceinhighquantumyields.Comparedtotheirprototypeslackingoftert-butylsubstituents,thetwonoveliridium（Ⅲ）complexesbothhaveshorterlifetimesandimprovedornearlysimilarPLquantumefficiencies,implyingthattheexcitonquenchingisinhibitedeffectivelywhenmolecularsterichindranceincreases.Thetwochelateshavegreatpotentialtobeusedaselectrophosphorescentmaterials.

简介：Cationic乳胶与cationic表面活化剂通过苯乙烯(圣)和丁基acrylate(BA)的乳剂copolymerization被准备，cetyltrimethyl铵溴化物(CTAB)。包括粒子尺寸，乳胶性质缩放分发，潜力，表面紧张和单体变换，为与不同CTAB数量准备的乳胶被决定。这些性质的进化在乳剂聚合期间被跟随以便理解粒子形成的机制。结果证明粒子尺寸和潜力是聚合时间和乳胶固体的功能。有cationic的平行乳剂聚合，anionic控告了开始者，没有费用的开始者也被执行，乳胶性质在不同聚合时间被决定。所有这些结果专心地基于乳剂聚合，表面活化剂吸附和乳胶粒子稳定的机制被解释。

简介：

简介：在求数列{1/n!(n/e)}的极限时,应用司特林(J.Stirling)公式

简介：Theformationmechanismofmonodispersepolymerlatexparticlesintheemulsifier-freeemulsionpolymerizationofmethylmethacrylateandbutylacrylatewithpotassiumpersulfateasinitiatorwasinvestigated.Amulti-stepformationmechanismforthemonodispersepolymerparticleswasproposed.Thenucleationmechanismisconsideredtobethecoagulationoftheprecursorparticlesbyhomogeneousnucleationwhentheprimaryparticlesreachacriticalsizewithhighsurfacechargedensityandsufficientstability.Ithadbeenprovedbyaspecialexperimentthattheearlylatexparticlesformedbythecoagulationwerestable.Theprimaryparticlesgrowbyabsorbingmonomersandradicalsinthepolymerizationsystemandthenbecomecolloidallyunstableagainduetotheunderstandabledecreaseofparticlesurfacechargedensity,whichleadstotheaggregationofthegrowingparticlesandtheformationoflargerlatexpediclestherefrom.Anerthenucleationperiod,thepreferentialaggregationofthesmallerparticlesinthepropagationprocessleadstothechangeoftheparticlestowardsauniformsizeandnarrowerparticlesizedistribution.Thecoexistenceandcompetitionofhomogeneousnucleation,coagulation,propagationandaggregationresultintheincreaseofthepolydispersityindex(U=D43/D10)inthefirstStage,thenitsdecreaseinthelaterstagebecauseofthecompetitionofpropagationandaggregation,andthegradualformationofthemonodisperseparticles.

简介：一系列α-N，有不同分子量的N-dihydroxyethylaminopropyl-ω-butylpolydimethylsiloxanes被综合。准备包括了是氢氧根保护，完化，离子的戒指洞聚合，hydrosilylation和deprotection的五步。反应产物的结构被英尺红外描绘，GC，1HNMR。

简介：Low-energypartial-waveπNscatteringdataisreexaminedwiththehelpoftheproductionrepresentationofpartial-waveSmatrix,wherebranchcutsandpolesarethoroughlyunderconsideration.Theleft-handcutcontributiontothephaseshiftisdetermined,withcontrolledsystematicerrorestimates,byusingtheresultsofO(p^3)chiralperturbativeamplitudesobtainedintheextended-onmass-shellscheme.InSnandPuchannels,severediscrepanciesareobservedbetweenthephaseshiftdataandthesumofallknowncontributions.Statisticallysatisfactoryfitstothedatacanonlybeachievedbyaddingextrapolesinthetwochannels.WefindthataSnresonancepolelocatesat√zr=(0.895±0.081)—(0.164±0.023)iGeV,onthecomplexs-plane.Ontheotherhand,aFnvirtualpole,asanaccompanyingpartnerofthenucleonbound-statepole,locatesat√zv=(0.966±0.018)GeV,slightlyabovethenucleonpoleontherealaxisbelowthreshold.Physicaloriginofthetwonewlyestablishedpolesisexploredtothebestofoiirknowledge.ItisemphasizedthattheO(p^3)calculationgreatlyimprovesthefitqualitycomparingwiththepreviousO(p^2)one.

简介：SupposethatCisthecomplexplaneandkisanon-negativeinteger.DefinefunctionsNk-(x)=|x|kifkisevenandNk(x)=x|x|k-1ifkisodd.SomeapproximationpropertiesofNk-(x)’sisdiscussedandanewexampleofaTchebycheffsystemisgivenout.

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简介：在这份报纸，我们在Rn定义领域的一个班。用反映Brownian运动的同步联合，我们与Neumann边界条件获得热方程的答案的monotonicity性质。我们然后证明热点为域的这个类推测抓住。

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简介：Polystyrenemacromonomerswithdifferentmolecularweightwerepreparedbyradicalpolymerizationofstyrene(St)inbenzeneusingβ-methacryloxylethyl2-N,N-diethyldithiocarbamylacetate(MAEDCA)asamonomer-iniferter.Characterizationofthemacromonomerby~1H-NMRshowedthattheendgroupswereα-methacrylyoxylethyloxycarbonyl-methylandω-(N,N-diethyldithiocarbamyl).Themacromonomerwasdifficulttohomopolymerize,butitwaseasilycopolymerizedwithmethylmethacrylate(MMA)initiatedbyAIBNtoformgraftcopolymers(PMMA-g-PSt)withPStbranchesrandomlydistributedalongthePMMAbackbone.CopolymerizationreactionandthestructureofthegraftcopolymerswerestronglyaffectedbyM_nandconcentrationofthemacromonomer.ThecompositionandM_nofthepurifiedgraftcopolymerweredeterminedby~1H-NMRandGPCanalysis.

简介：AnewkindofpolysiloxanecontainingN,N’-bis（diphenylsilyl）tetraphenylcyclodisilazanewaspreparedbyanionicnon-equilibriumpolymerizationwitha"seedsolution"asinitiator.Themonomer,N,N’-bis（hydroxydiphenylsilyl）-tetraphenyl-cyclodisilazane（BHPTPC）,wassynthesizedviathehydrolysisofN,N’-bis（chlorodiphenylsilyl）tetraphenyl-cyclodisilazane（BCPTPC）.AnewmethodforthepreparationofBCPTPCisalsoreportedherewithhighyieldandsimplermanipulation.ThesynthesizedpolysiloxanecontainingN,N’-bis（diphenylsilyl）tetraphenylcyclodisilazanewascharacterizedby1H-NMR,29Si-NMR,gelpermeationchromatography（GPC）andintrinsicviscosity.