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1.
张冬辉  周向东  周维善 《中国化学》2002,20(11):1145-1148
Cerebrosterol (2 4S hydroxycholesterol,1)formedinsmallamountsinhumanandanimalbrain1fromcholes terolisimportantforcholesterolhomeostasisinthisorgan .Theexcesscholesterolisconvertedinto 2 4S hydroxy cholesterolbyauniquebrain specific 2 4S hydroxylase ,whichcouldber…  相似文献   

2.
IntroductionSupramoleculeisakindofsystemwithspecialstruc turedependingontheweakmolecularinteractions (suchasvanderWaals ,hydrogenbond ,electrostaticandhy drophobicinteractions) .Theweakinteractionsarerelatedtobiologicalprocesses ,forexample ,thecatalyticrea…  相似文献   

3.
Nitronicacidsandnitronicestersarespecialspeciesoforganiccompounds,whosestrikingpropertyisinstability[1—3].Duetothisreason,studiesrelatedtothesespecieshaveprogressedveryslowly.Recently,wereportedthesynthesisofstablenitronicacidIandnitronicesterII[4—6](fig.1),a…  相似文献   

4.
BasedonthecrystalstructuredatafromXrayanalysis[1,2]andthespectralpropertiesofeachchromophoreofCPC[3,4],Sauerandcoworkers[5,6]expectedthatthedynamicsofenergytransferprocessesshouldtakeplacewithin10—30pstimescalebetweentwotrimersofCPChexamer.Furthermore,Zhaoandco…  相似文献   

5.
Recentprogressinsurfacespectroscopyandmolecularbeamscatteringanddetectiontechniquesmakesitnowpossibleatthemicroscopicleveltoaccuratelymeasuresuchthingsasdissociationrates,adsorbatebindingandgeometry,andmobilitiesofadsorbedspeciesonsurfaces.Thiskindofe…  相似文献   

6.
IntroductionThesupramolecularcomplexeformedbytheweakinteractions (electrostaticinteraction ,hydrogenbonds ,vanderWaalsforce ,short rangeexclusionforce ,etc .)ofmorethantwosortsofspeciesisanorganizingentitythatusuallypossessesspecialstructureandfunction .1Sup…  相似文献   

7.
IntroductionItiswellknownthatyttriumcanbeusedinmanyfields ,suchasmetallurgy ,ceramics ,lasersandelectron ics ,especiallyinfluorescentmaterialswhoseneedforhighpurityyttriumoxideisincreasing .InChina ,there sourceofyttriumisrich ,andthehighpureyttriumisbe ingo…  相似文献   

8.
Co ̄ndenceauthor.Oaf((k6<l)adspeciesPeakswerefoundtodisappearat573'K.Duringthetemperatureelevation,theCeOZFZgandO2-Peakswerefoundtobroadenandshifttolowerwavenumbers.ThefhaluencyshiftwilhresecttotemperatureisawellknownphenomenoninRamanspectroscopyofsolidsanditisrelatedtothetherma]expansionoflatticeparameters.At1023'K,theO2-adspecies(at1159cm-l)andCeOZF2,(at449cm-l)peakswerefoundtoremainexistingonthesurfaceofceriumoalde.WhentheOZ-pretreatedCeOZsamplewaswarmedsuccessivelyinaflowofCd,thereachonsofCabwithlaniceo  相似文献   

9.
FECS ,theFederationofEuropeanChemicalSoci eties,comprisesanumberofDivisionsandWorkingPar tiesspecializingincertainfieldssuchasFoodChem istry ,ElectrochemistryorChemicalEducation .AmongthemtheDivisionofAnalyticalChemistry ,DAC ,isoneofthelargestwithrespectto…  相似文献   

10.
Incomparisonwiththealuminumanalogues,boroncontainingMFItypezeolitehasbeenexpectedtohavemilderacidicpropertiesandspecificcatalyticperformance.Uptonow,muchworkhasbeendoneinthisaspect[1—5],includingsynthesis,structuralcharacterizationandcatalysis,etc.Therear…  相似文献   

11.
IntroductionExchange coupledpolynuclearcopper(II)complex esareofspecialinterestduetotheirinvolvementinbio logicalprocessesandininorganicmaterials .1,2 Theinti materelationshipbetweenthespincouplingandthemolecularstructurehasfosteredtheemergenceofmolec ular…  相似文献   

12.
IntroductionCalorimetryhasbeenusedinmonitoringcellularmetabolismbymeansofheatmeasurements ,especiallyinstudyingmetabolismincellsandwholeorganism .1,2 Mi crocalorimetryisalsousedinmeasuringtheeffectsofvar ioussubstancesandcultureconditionsonmetabolism .Mile…  相似文献   

13.
IntroductionInadditiontothehighlyspecificcell-mediatedimmunesystem,vertebratesandotherorganismshaveadefensesystemmadeupofdistinctgroupsofbroad-spectrumantibacterialpeptides[1—3].Antibacterialpeptidescanbeclassifiedintotwogroupsbasedonhavingdisul-fide…  相似文献   

14.
PROFESSORJIAXILU(CHIA-SILU):FounderofChineseJournalofStructuralChemistryABriefBiography¥ProfessorJiaxiLu,myrespectedteacheran...  相似文献   

15.
Introduction  Non covalentinteractionshaveabiginfluenceontheconformationalorganizationofthebiomoleculeswhichisresponsiblefortheregio andstereo specificityofvariousbiologicalprocesses .1Amongtheseinteractions ,thein tramolecularstackinginteractionbetweens…  相似文献   

16.
朱士正  金桂芳  Des Marteau  D.D 《中国化学》2002,20(11):1268-1273
IntroductionInthepastdecades ,considerableresearchworkhasbeenfocusedonthefluorinatedionomers1 4 whichhaveexceptionalthermalandchemicalstabilities .5Thereforetheyhaveshownspecialapplications ,suchasmembraneseparationintheelectrochemicalprocessesandsuperaci…  相似文献   

17.
宋力平  朱士正  黄吉玲 《中国化学》2002,20(11):1274-1278
Introduction4 ,5 Dihydropyrazolederivativeshavebeenstudiedextensivelyduetotheirdiversechemicalreactivity ,broadspectrumofbiologicalactivityandvarietyofindustrialap plication .1Inaddition ,itisknownthat 4 ,5 dihydropyra zolederivativeswereusefulcompoundsnotonl…  相似文献   

18.
IntroductionCycloadditionreactionshavebeenextensivelyusedinorganicsyntheses,especialyinthesynthesesofmedicine,aromatizerandna...  相似文献   

19.
Itisdifficultandevenimpossibletodeterminebyregularkineticsmethodssomekineticsparametersofsomecomplexchemicalreactions,especiallypolymerizationreactionswhosemechanismshavenotbeenknown.Wehavetriedtosolvethisproblembythemethodofregressionandsimulationofc…  相似文献   

20.
Interleukin-2(IL-2)isa133-aminoacidlymphokineproteinsecretedbyactivatedT-cels.Itsbiologicalefectsaremediatedbybeingboundtospe...  相似文献   

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