学科分类
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22 个结果
  • 简介:有分叉的烃链的酚衍生物的聚集和deaggregation行为在CH3OH和缓冲区答案被学习了。有聚集数字测量和房间粘附实验的联合,目标分子的deaggregating能力上的结构效果被讨论。结果显示2-phytyl-4-methoxylphenol(11)是在学习的系统的最有效的deaggregator。

  • 标签: 苯酚 衍生物 聚合反应 碳氢化合物
  • 简介:Thephotoelectrochemicalbehaviorofpolyaniline(PAn)filmwasstudiedinaqueouselectrolytesolutioncontainingFe(CN)63-/Fe(CN)+4-redoxcouple.ItwasfoundthatPAnfilmspossessthepropertiesofp-typesemiconducterandacathodicphotocurrentashighas700μA/cm2wasobservedwhenirradiatedunderpolychromaticlightof100mW/cm2.

  • 标签: cathodic ELECTROLYTE redox IRRADIATED irradiation DOPING
  • 简介:Phosphatidylcholines(Ln’s)andtheirneutralanalogs1,2-diacyl-sn-glycerol-3-phospho-ricacidbromoethylesters(Pn’s)havebeenfoundtoexhibitdifferentaggregationbehaviorsbroughtaboutbyhydrophobic-lipophilicinteractions(HLI)bymeansofkineticprobeinMeOH-H2Obinaryaquiorganicsystems.Theeffectsofthestructureandtheenvironmentontheinterestingaggregationoftheamphiphilicmoleculesarediscussed.

  • 标签: Kinetic probe PHOSPHATIDYLCHOLINE hydrophobic-lipophilic interactions aggregating
  • 简介:Photoisomerization(trans-cis)ofazoaromaticcompoundshasbeeninvestigatedextensivelyusingabsorptionspectroscopysince1950s[1].Byirradiationwithlightofwavelengthλ1orλ2,thegeometricconfigurationoftheazobondinazobenzenebasedcompoundscanbereversiblyswitchedfromtranstocis.Thetwostateshavedistinctabsorptionspectra.Thisfeaturewouldallowreversiblestorageofdataonthebasisofcisandtransstateswiththeaidofλ1andλ2.However,thecisstateisthermodynamicallyunstablewithrespecttothetransstate,thereforeathermalrelaxationprocessoccursinthedark(atroomtemperature).Thisthermalback-reactionstronglylimitsthelifetimeofthecisstate,anditisinfluencedbythesubstituentR1andR2,catalysts,temperature,andenvironment(solventpolarity,typeofpolymermatrix)[2].

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  • 简介:TheconstructionofadsorptivetypeC60modifiedelectrodeanditselectrochemicalreductionandoxidationbehaviorinaqueoussolutionsaredescribedinthisreport.Fourpairsofone-electrontransferreductionandoxidationcyclicvoltammetryisobtainedinaqueoussolutioncontaining30%CH3CNand2%(C2H5)4NOH.ItisreportedinthispaperthattheC60modifiedelectrodealsocatalyzestheelectrochemicalreductionofdissolvedoxygenin40%DMFand2%(C2H5)4NOHaqueoussolutionandthismightopenanewfieldforthepotentialapplicationsofC60inelectrochemistryandelectroaualyticalchemistry.

  • 标签: C60 modified ELECTRODE electrochemistry.
  • 简介:以便为有毒的N2O分子,有N2O分子用密度被调查功能的理论计算。不同于太古的表,做Al的表能有效地与N2O分子以便它的电子性质和电导率戏剧性地被改变。我们相信用一个艾尔原子代替BN表的一个B原子可以是为向N2O,它不能被太古的表套住并且检测。

  • 标签: 氧化亚氮 纳米 BN 分子检测 行为 感知
  • 简介:Theaggregationbehaviorandstructureofhydrophobicallymodifiedblockcopolymersofacrylamideand2-phenoxylethylacrylatewereinvestigatedbyviscometry,1HNMRrelaxation,2DNOESY,fluorescenceanddynamiclightscattering.Itwasfoundthattheaggregationbehaviorwasstronglydependentontheconcentrationofpolymersolutionandthehydrophobecontents.Withvaryingconcentrationfrom2.0,6.0,8.0to12.0g/L,thereweredifferentaggregatemorphologiesdistributedinaqueoussolutions,suchasmonopolymerchain,micelle-likeaggregate,multi-micelleaggregateandcross-linkednetwork.Accordingtothemodelofaggregation,itcangiveareasonableexplanationonthelargemagnitudeenhancementofviscositywiththeincreasingofpolymerconcentration.Additionaldataof2DNOESYandfluorescenceshowthatthecopolymerwithhigherhydrophobecontent(molarfraction≥1%)islikelytoformintra-molecularassociation.

  • 标签: 疏水改性聚丙烯酰胺 聚集行为 结构 嵌段共聚物 NOESY 聚合物溶液
  • 简介:Thesynthesisandphasebehaviorofaseriesof4’-alkyloxy-4-hydroxybiphenylswerediscribed.Theeffectsofreactionconditionsontheyieldsofproductswereinvestigated.Thecharacterizationsofthermotropicliquidcrystallineproductsforthetypeandthermalpropertiesarediscussedthroughtheuseofdifferentialscanningcalorimetry,polarizingmicroscopy.

  • 标签: crystalline ATTRACTIVE spectrometer PHOTOGRAPH CALORIMETRY melting
  • 简介:ThepropertiesofPbn(n=2―30)clustersincludingbindingenergies,seconddifferencesinenergy,andHOMO-LUMOgaps,especiallyfragmentationenergiesandionizationpotentials,havebeenstudiedbyabinitiocalculation.ThemainfragmentationproductsofPbn+areshowntobePb+Pbn-1+forn≤14andtwosmallclusterfragmentsforlargeroneswithn>14.ThePb13+appearsfrequentlyastheproductsinthefragmentationsoflargeclusters.Also,thecalculatedionizationpotentialsoftheclustersareconsistentwiththeexperimentdata.

  • 标签: 电离势 碎裂 集群计算 HOMO LUMO 从头计算
  • 简介:TheelectrooxidationofBilirubin(BR)inN,N’-dimethylformamide(DMF)andDMF+H2Omixedsolventisinvestigatedbyvoltammetrytechniques,insiturapidscanthinlayerspectroelectrochemistryandinsituESRspectroscopy.ThedatarevealthattheoxidationprocessofBRundergoesmanystages,whichareallspedupbytheintroductionofwater.ThespeciesofbilirubintakingpartinthereactionisfoundtobechangedfromBRinDMFintoBR’inthemixedsolventsandtheanodicpeakpotentialisshiftedcorrespondinglyfrom+0.58Vto+0.026-+0.35V(vs.Ag/AgCl,1.0MKCl).Freeradicalsandthedimerizationofthemareobservedduringtheoxidation.

  • 标签: ELECTROOXIDATION BILIRUBIN biliverdin.
  • 简介:AnovelacrylicmonomerbearingaromaticetherealitygroupN-(p-phenoxy-phenyl)methacrylamide(MAPOA)wassynthesizedandpolymerized.ThefluorescencespectraofMAPOAanditspolymerwerestudied,showingthatthepolymerdisplaysastrongerfluorescencethanitsmonomeratthesamechromophoreconcentration.ThefluorescenceofP(MAPOA)wasquenchedbyaddingelectrondeficiencymonomerssuchasMMA,ANetc..Itisanotherexampleofshowingthe"fluorescencestructuralself-quenchingeffect"aswereportedpreviously,fromwhichitisdemonstratedagainthatthisphenomenonisnotanaccidentalonebutacommoneffectforacrylicmonomersbearingelecton-donatingchromophores.ThephotopolymerizationofANsensitizedbyMAPOAandP(MAPOA)wasstudied.Thekineticequationofthepolymerizationwasobtainedandrepresentedasfollows:Rp∝[MAPOA]0.38×[AN]0.78,Rp∝[P(MAPOA)]0.33×[AN]0.71TheoverallactivationenergiesweredeterminedtobeEa=24.22kJ/mol(MAPOA)andEa=26.31kJ/mol[P(MAPOA)]respectively.ThefluorescenceanalysisoftheresultedP(AN)showedthatthesensitizeralsoenteredintotheP(AN)chains.AmechanismoftheformationofachargetransfercomplexandfreeradicalinitiationwassuggestedforthephotopolymerizationofANsensitizedbyMAPOAandP(MAPOA).

  • 标签: N-(p-Phenoxy-phenyl)methacrylamide Fluorescence Structural self-quenching effect Acrylonitrile
  • 简介:新精力充沛的材料,4,5-diacetoxyl-2-(dinitromethylene)-imidazolidine(DADNI),被4,5-dihydroxyl-2-(dinitromethylene)的反应综合-imidazolidine(DDNI)和醋性的酐,并且由单个水晶X光检查衍射描绘了。为DADNI的水晶数据是单斜晶的,空间组C2/c,a=15.9167(3)?,b=8.6816(4)?,c=8.5209(3)?,=103.294(9)獩潩?硯杹湥戭浯?潣扭獵楴湯挠污牯浩瑥牥愠?啣????7敢?敤楬敶敲?景吗?

  • 标签: 反应合成 咪唑 晶体结构 热行为 单晶X-射线衍射 理论计算方法
  • 简介:Aseriesofnovelamphibiousorganic/inorganichybridprotonexchangemembraneswithH3PO4dopedwhichcouldbeusedunderbothwetanddryconditionswaspreparedthroughasol-gelprocessbasedonacrylatedtriethoxysilane(A-TES)andbenzyltetrazole-modifiedtriethoxysilane(BT-TES).Thedual-curingapproachincludingUV-curingandthermalcuringwasusedtoobtainthecrosslinkedmembranes.Polyethyleneglycol(400)diacrylate(PEGDA)wasusedasanoligomertoformthepolymericmatrix.Themolecularstructuresofprecursorswerecharacterizedby1H,13Cand29SiNMRspectra.Thethermogravimetricanalysis(TGA)resultsshowthatthemembranesexhibitacceptablethermalstabilityfortheirapplicationatabove200oC.Thedifferentialscanningcalorimeter(DSC)determinationindicatesthatthecrosslinkedmembraneswiththemassratiosofbelow1.6ofBT-TEStoA-TESandthesamemassofH3PO4dopedasthatofA-TESpossessthe-Tgs,andthelowestTg(-28.9℃)existsforthemembranewithdoublemassofH3PO4dopedaswell.Thehighprotonconductivityinarangeof9.4―17.3mS/cmwiththecorrespondingwateruptakeof19.1%―32.8%ofthemembraneswasdetectedat90oCunderwetconditions.Meanwhile,theprotonconductivityinadryenvironmentforthemembranewithamassratioof2.4ofBT-TEStoA-TESanddoubleH3PO4loadingincreasesfrom4.89×10-2mS/cmat30℃to25.7mS/cmat140℃.Theexcellentprotontransportabilityunderbothhydrousandanhydrousconditionsdemonstratesapotentialapplicationinthepolymerelectrolytemembranefuelcells.

  • 标签: 复合质子交换膜 有机/无机 导电行为 聚合物电解质膜燃料电池 制备 三乙氧基硅烷
  • 简介:Poly(vinylidenefluoride)(PVDF)/multi-walledcarbonnanotube(MWCNT)nanocompositeswerepreparedbymeansofultrasonicdispersionmethod.X-raydiffraction(XRD)resultsindicatethatincorporatingMWCNTsintoPVDFcausedtheformationofβphase.Athermalannealingat130°Cconfirmedthattheβphasewasstableinthenanocomposites.Differentialscanningcalorimetry(DSC)resultsindicatethatthemeltingtemperatureslightlyincreasedwhiletheheatoffusionmarkedlydecreasedwithincreasingMWCNTcontent.ThetensilestrengthandmodulusofPVDFwereimprovedbyloadingtheMWCNTs.Thescanningelectronmicroscopy(SEM)observationsshowedthatMWCNTswereuniformlydispersedinthePVDFmatrixandaninterfacialadhesionbetweenMWCNTandPVDFwasachieved,whichwasresponsiblefortheenhancementinthetensilestrengthandmodulusofPVDF.

  • 标签: 多壁碳纳米管 纳米复合材料 聚偏氟乙烯 结晶行为 差示扫描量热法 扫描电子显微镜
  • 简介:Phasebehaviorofbinarysystemofbromobenzene-chlorobenzene(C6H_5Br-C_6H_5Cl)confinedinSBA-15andMCM-41(porediameter8nm,3.8nm,respectively)hasbeeninvestigatedbymeansofdifferentialscanningcalorimetry(DSC).PhasediagramofC_6H_5Br-C_6H_5ClsystemconfinedinSBA-15isatypeofthecompletemisciblebothinliquidandsolidstate,thesamephasebehaviorasthebulksystem.However,thephasediagramcomprisesonlyoneboundaryline,whichisshifteddown22-36Kwithrespecttothebulksystem.C_6H_5Br,C_6H_5ClorthemixturewithinnanoporesofMCM-41isnonfreezing.ThedifferentphasebehaviorofthesystemconfinedinSBA-15andMCM-41isthoughtmainlyduetotherelativesizeofporetomolecule.

  • 标签: MCM-41 SBA-15 二元系统 相行为 氯苯 溴苯
  • 简介:WiththedecreaseofpHvaluefrom8.45to–1.0,theUV-Visabsorptionandfluorescentspectraof1,2-bis(4-pyridyl)ethylene(BPE)tookonthesamechangingtrendatfourdifferentsuccessivepHstages:8.45―7.20,7.20―5.62,5.62―2.60,and2.60―-1.0,namely,nochange,decrease,increase,anddecreaseagain.Amongthese,inarangeof7.20―5.62,thefluorescencewavelengthblueshiftedfrom418to359nm,buttheUV-Visabsorptionwavelength,incontrast,redshiftedfrom285to298nm.ThefluorescenceintensityofBPEhadadropeventoquenchuponadeclineinthepHvaluefrom2.60to–1.0probablyowingtoitscation-πinteractiontoreducetheπelectronclouddensityofBPE.Twodissociationconstants,pKa1(4.30±0.01)andpKa2(5.65±0.04),wereobtainedbasedonfluorescencedata.ThechangesoffluorescencespectraindicatethatBPEhas'off-on-off'switchbehavior.ThefluorescentspectraofBPEwerenearlyindependentonthepresenceofα-andβ-cyclodextrins.

  • 标签: 乙烯 荧光转换 荧光探针 阳离子交互作用 水解