简介：根据Ａｆ－Ａｇ自由基加聚反应的数量分布函数，导出凝胶点附近的渐进分布函数和高分子矩的表示式．进一步应用标度变换，得到了描述溶胶－凝胶相变的广义标度律，从而揭示了Ａｆ－Ａｇ自由基加聚的固化反应是一个相变过程．

简介：Quasiclassicaltrajectorycalculation(QCT)isusedfrequentlyforstudyingcollisionalenergytransferbetweenhighlyvibrationallyexcitedmoleculesandbathgases.Inthispaper,theQCToftheenergytransferbetweenhighlyvibrationallyexcitedC6F6andN2,O2andgroundstateC6F6wereperformed.TheresultsindicatethathighlyvibrationallyexcitedC6F6transferredvibrationalenergytovibrationaldistributionofN2,O2andgroundstateC6F6,sotheyareV-Venergytransfer.EspeciallyitismainlyV-VresonanceenergytransferbetweenexcitedC6F6andgroundstateC6F6,excitedC6F6transfersmorevibrationalenergytogroundstateC6F6thantoN2andO2.ThevaluesofQCT,-〈△Evib〉ofexcitedC6F6aresmallerthanthoseofexperiments.

简介：ＯｘｉｄａｔｉｖｅＤｅｈｙｄｒｏｇｅｎａｔｉｏｎｏｆＩｓｏｂｕｔａｎｅｔｏＩｓｏｂｕｔｙｌｅｎｅｏｖｅｒＦ￣－ＭｏｄｉｆｉｅｄＲａｒｅＥａｒｔｈＭｅｔａｌＯｘｉｄｅＣａｔａｌｙｓｔｓＺＨＡＮＧＷｅｉ－ｄｅ，ＴＡＮＧＤｉｎｇ－ｌｉａｎｇ，ＬＡＩＷｅｎ－...

简介：利用密度泛函理论（Densityfunctionaltheory，DFT）在B3LYP／6-311＋＋G（d，声）水平上研究了外电场（-15．43～15．43V／nm）对氟利昂F13（三氟氯甲烷，CRCl）分子物理和光谱特性的影响．计算结果表明，在C～Cl键连线z方向上，外电场从-15．43V／nm逐渐增加到15．43V／nm时，分子体系能量先增大后降低，偶极矩表现为先减小后增大，能隙ElG先增加后减小，C-Cl键键长逐渐增大，C-F键键长逐渐减小．外电场对CRCl分子红外振动光谱的频率和强度也有影响．进一步研究发现在外电场作用（O到15．43V／nm）逐渐增强下，CRCl分子的势能曲线束缚形态逐渐被解开，解离的势垒逐渐减小．在强度为15.43V／nm的电场作用下，CF3Cl分子将会发生C-C1键断裂而降解，该结果为对氟利昂进行外电场降解提供重要的参考依据．

简介：NaphtholgreenBwasused,forthefirsttime,asanewmediatorinanamperometricglucosebiosensor.Itisagoodmediator,promotingelectrontransferfromglucoseoxidasetographiteelectrode.Thebiosensorshowshighsensitivitytoglucoseatlowpotentialwithresponsetimeof30seconds.Thelinearrangeisfrom1.5to18μmol/Lglucosewithdetectionlimitof0.5μmol/Lglucose.

简介：二新自然杂环的混合物bretschneiderazinesA(2)和B(3)的灵巧的合成，从Bretschneiderasinensis的茎的一篇摘录孤立，被报导。我们作为关键步骤与硫和光气由指导lithiation和顺序的处理采用了benzamide的环合反应。所有新混合物充分借助于红外，1HNMR，13CNMR，和HRMS被描绘了。

简介：TofindoptimalconditionsforexpressingthesolubleformofsFv-2F3andtostudythepurificationandpropertyofitsderivativeSe-sFv-2F3,thepreferredexpressionconditionswereinvestigatedbymeansoforthogonaldesign.Thesecultureconditionsincludedincubationtemperature,inducerconcentration,inductiontimeandcellconcentration.TheevaluationofexpressionwasaccomplishedbytheanalysisofwholecelllysatesandtheyieldofsolublesFv-2F3wascalculatedaccordingtotheanalysisofProfinder(FTI-500,Pharmacia).Thepurificationprocedurewascarriedoutviaatwo-steppurificationprocedureconsistingofion-exchangechromatography,followedbyimmobilizedmetalaffinitychromatography(IMAC).TheantioxidantefficacyofSe-sFv-2F3wasdemonstratedbythedeterminationofthecontentofthemainproductoflipidperoxidation,MDA,theviabilityofcellsandtheactivityofLDH.WeobtainedthepreferredcultureconditionstogrowtheengineeredbacteriaandtheprocedureforpreparingsolublesFv-2F3andconfirmedtheantioxidantefficacyofSe-sFv-2F3.

简介：Thepaperdealswiththeinfluenceofanodematerialontheefficiencyofdegradationfororganicpollutantsinwatersystem.Theelectrochemicalperformanceoffluorineiondopedleaddioxide(F--PbO2)electrodeforthedegradationofanilinewascomparedwiththatofundopedleaddioxide(PbO2)electrodebyultraviolet-visible(UV-Vis)spectroscopy,linearvoltammetryandotheranalyticalmethods,suchasthemeasurementbychemicaloxygendemandanalyzer,highperformanceliquidchromatographyandscanningelectronmicrography.ItwasshownthatbothPbO2electrodeandF--PbO2electrodecouldmakeanilinebemineralizedcompletelyandhavethesamedegradationcourse,butF--PbO2electrodehasmuchhigherelectrocatalyticactivitythanundopedPbO2electrodefortheelectrochemicaldegradationofaniline.TheexperimentalresultsconfirmthatF--PbO2electrodehasmuchhigherpotentialforoxygenevolutionthanundopedPbO2electrode.

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简介：采用密度泛函B3LYP/6-311G（d,p）方法对CH3F与C2H3的反应体系进行了理论研究,获得了反应的势能面信息及可能的微观机理.在QCISD（T）/6-311＋＋G（d,p）水平上精确计算了各反应物种的单点能.结果表明,除抽提氢反应外,标题反应还存在抽提氟（R1）、消氟化氢（R2）、消氢（R3）和自由基形成（R4）四类反应.在QCISD（T）/6-311＋＋G（d,p）//B3LYP/6-311G（d,p）水平上,R1,R2,R3和R4反应的能垒分别是163.9,152.2,209.8和224.2kJ·mol-1,相应反应能为-56.6,-164.3,-2.7和-156.0kJ·mol-1,所有反应均放热,为热力学允许的反应.

简介：AbinitiomolecularorbitalcalculationsofdoublynegativechargedB16H162-(D2)andneutralB16H16(Td)havebeendoneattheHF/6-31Glevel.TheyarepredictedtobechemicallyandkineticallystablebyvibrationalanalysesontheirrespectiveenergyhypersurfaceoftheHF/6-31Glevel.ThegeometricalstructureofthespeciesB16H1622-(D2)wasdiscussed.

简介：FluorescencequenchingofjanusgreenB(JGB)insodiumdodecylsulfate(SDS)micellebynucleicacids(DNA)wasstudiedusingUV-visabsorption,steadystatefluorescenceemissionmethodsandlifetimemeasurements.IntheSDSmicelle,weakfluorescenceofJGBwasenhanced,andthemaximumemissionshiftedfrom425to410nm.InthepresenceofDNA,thefluorescenceofJGBwasquenched.Linearrelationshipsbetweenthefluorescencequenching(F0/F)andconcentrationsofDNAwereobservedintherangeof2.4×10^-8to1.08×10^-7mol·L^-1forcalfthymusnucleicacids(ctDNA)and1.9×10^-8to3.8×10^-8mol·L-1forfishspermnucleicacids(fsDNA)when2.5×10^-5mol·L^-1JGBwasemployed.Thelimitdetectionwere1.3×10^-8mol·L^-1forctDNAand6.4×10^-9mol·L^-1forfsDNA.AthighDNAconcentration,therewasasystematicdeviationfromtheStem-Volmerequationduetothestaticanddynamicquenchingoccurringsimultaneously.TheproposedmethodwasappliedtothedeterminationofthenucleicacidsinchickenbloodextractionandtheanalyticalresultswereingoodagreementwiththeUV-method.

简介：FournewtaxanediterpenoidswereisolatedfromthebarkofTaxusyunnanensis.Theirstructureswereelucidatedasthenewskeletonwith5/7/6/4memberedringsbyspectralanalysisand2DNMRshiftcorrelationexperiments.

简介：Astudywasmadeofmagneticfieldeffects(MFEs)onthephotoreductionreactionof2-methyl-1,4-naphthoquinone(MNQ)inBrij35micellarsolutioncontaining4-1auroylamino-TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyl)radical(L-R·)undermagneticfieldsbelow1.75Tbyananosecondlaserflashphotolysistechnique.ThetripletMNQmainlyunderwentthehydrogenabstractionfromBrij35moleculetogivearadicalpair.Theescapedradicalyieldincreasedwithmagneticfieldsfrom0to0.62Tandthensaturatedfrom0.62to1.75T.MFEsforbothsystemscanbeexplainedbytherelaxationmechanism.However,itwassupposedthatadditionalradical,L-R.affectedtheMFEsmainlythroughenhancingthespin-spininteractionsofradicalpairs.TheeffectofthemicellesizeonMFEsofthestudyingsystemwasalsodiscussed.

简介：在MP2/6-311＋＋G＊＊水平上优化乙烯酮自由基与LiX（X=F,Cl,Br）形成锂键复合物.当卤素的电负性很强（如F元素）,使得Li原子处于缺电子状态,此时,电子给体会把电子偏移向锂,形成共价性较强的锂键.而当卤素的电负性减弱时,锂键中主要成分逐渐变为离子键,并且此时锂键性质还要受电子给体影响.另外,由于HCCO为缺电子结构,电负性较弱且体积较大的卤素中的孤对电子会与HCCO之间通过静电相互作用,使得HCCO…Li—X键夹角变小,接近120°.锂键性质对HCCO…LiX（X=F,Cl,Br）复合物中Li—X的伸缩振动频率有直接影响.当锂键表现为共价性时,该频率红移,而当锂键表现为离子性时,该频率蓝移.但是,由于Cl的电负性与O的接近,C的电负性与Br接近所以,在O…Li…Cl和C…Li…Br中容易形成共振结构,导致远大于在其他复合物中的红移.

简介：TwoseriesofterritremBanalogues(10a-10cand18)havebeendesignedandsynthesizedfromjujubogenin5awhichwaspreparedfromjujubogeninglycosides5bobtainedfromtheleavesofZizyphusjujuba.Thestructuresofthenewcompoundswereconfirmedby1H-,13C-NMRandMSdata.Compounds10cand18showedweakinhibitoryeffectonAChEat10^-4mol/E.

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简介：Afacileandconvenientsynthesismethodhasbeendevelopedforsubstitutedquinoxalinesand2H-benzo[b][1,4]oxazinesfromthereactionsofα-bromoketoneswithbenzene-1,2-diamineand2-aminophenol,respectively,whichwerecatalyzedbytetrabutylammoniumbromide(TBAB)inaqueousbasicmedia.

简介：ThemethanolicextractfromaChineseendemicChrysanthemumplant,Dendranthemaindicumvar.aromaticum,wasfoundtoshowhighantifeedingactivityagainstPierisbrassicaeL.,andbybioassay-guidedseparation,theactivecomponent,B-ring-homo-tonghaosu,2-(2',4'-hexadiynylidene)-1,6-dioxaspiro-[4,5]-dec-3-ene(2)wasisolated.Itsstructurewaselucidatedbycomparingitsspectroscopicdatawiththoseof2reportedintheliteratures.FurthermorenewconvenienttotalsynthesismethodsofB-ring-homo-tonghaosuwerealsodevelopedtoconfirmitsstructureandmakeitsfurtherapplicationincropprotectionavailable.Inaddition,extensivecomparisonofspectroscopicdatashowedthatthestructureofcompound21reportedinliteratureshouldberevisedto2.

简介：极其细小磨擦非结晶的合金催化剂被化学减小与KBH4准备。在在气压的cinnamaldehyde的液体阶段加氢期间，Ru-B催化剂准备了展出优秀选择到cinnamyl酒精。当加氢与超声的照耀被执行时，当到cinnamyl酒精的选择仍然保持几乎未改变时，反应率能极大地被提高。加氢率随超声的频率或照耀时间的增加被增加。根据各种各样的描述，例如XRD，XPS，TEM，赌注和ICP，结构、电子的特征上的超声的照耀的效果磨擦催化剂简短被学习。同时，催化表演上的ultrasonication的提升效果也基于cinnamaldehyde的选择加氢被讨论到cinnamyl酒精。