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简介:Geant4LowEnergyElectromagneticpackageProvidesaprecisetreatmentofelectromagneticinterationsofparticleswithmatterdowntoverylowenergies(250oVforelectronsandphotons,<1keVforhadronsandions),Itincludesaverietyofmodelsfortheelectromagneticprocessesofelectrons,photons,hadronsandions,takingintoaccountadvancefeatures,suchasshelleffectsandeffectsduetochargedependence.Thecomprehensivesetofparticletypesitcanhandle,thevarietyofmodelingapproachesandtheextendedcoverageofenergyrangemakethispackageauniquetoolamongMonteCarlocodesonthemarket,andofrelevancetoserveralexperimentaldomainsinHIEP,astroparticlephysics,spacescienceandbiomedicalstudies.
简介:AseriesofcarboxylicacidswasesterifiedtothecorrespondingesterswithTiCl_4ascatalystatroomtemperature,inhighyields.Thiscatalystwashighlyeffectivefortheselectiveesterificationofprimaryalcoholswithcarboxylicacids,inthepresenceofsecondaryalcohols,andfortheselectiveesterificationofsaturatedacidwithalcoholinthepresenceofconjugatedacidoraromaticacid.Onaccountofthehighyield,highchemoselectivity,mildcondition,andbeingfreeofotherdehydrants,thisisanefficientmethod.
简介:Newboronoalkoxycalix[4]arenesweresynthesizedbyallylation,alkylation,hydroborationandhydrolysisof25,26,27,28-tetrahydroxycalix[4]arene,andidentifiedbyelementalanalysis,IR,1HNMR,13CNMR,11BNMR,MSandUVspectra.ThedataofUVandfluorescencespectrashowedthattctrapropoxycalix-[4]arenetriboronicacidcouldcoordinatesignificantlywithmonosaccharides.
简介:Duetotheirsize-dependentpropertiesandflexibleprocessingchemistry(Alivisatos,1996),monodispersednanocrystalshaveattractedconsiderableattentionfortheirdistinguishedroleinfundamentalstudiesandtechnicalapplications.AlthoughmuchhasbeenreportedonfabricationofmonodispersedinorganicnanocrystalssuchasFe2O3,CdSe,PbSeandZrO2(Peng&Peng,2002;Zhuetal.,2002;Niederbergeretal.,2002;Pangetal.,2001),littlepublishedonthepreparationofBaSO4nanocrystalsandtheircrystalsizeandmorphologywhichaffecttheirperformanceinapplication.PolymeradditiveswithcomplexfunctionshavebeenusedastemplatestodirectorientednucleationandgrowthofBaSO4(Xiaoetal.,2001;Yuetal.,2002;Summersetal.,2002),asanewclassoffunctionalpolymers,theso-calleddouble-hydrophilicblockcopolymers,designedtocontrolthemorphologyofBaSO4(Colfenetal.,2002),includingtheirnanofiberssynthesizedinAOTmicroemulsion(Li&Mann,2000).ThoughsomuchresearchhasbeendevotedtocontrollingtheBaSO4morphologies,thepresentnotewillreportonthesynthesisofBaSO4nanocrystalswithsizecontrolling.
简介:Thecombinationofboth4,4′-bipyridine(4,4′-bipy)anddihydrogenphosphateanionligandswithcopper(Ⅱ)resultsintheformationofanovellayeredcompoundCu(4,4′-bipy)2(H2PO4)2(H2O)2.ThecrystalstructurecomprisesdiscreteneutralCu(4,4′-bipy)2(H2PO4)2(H2O)2units.Thecopperatom,locatedonthecrystallographictwofoldaxis,iscoordinatedwithtwonitrogenatomsofterminal4,4′-bipyligandsandtwowatermoleculesattheequatorialpositions,andtwodihydrogenphosphateoxygenatomsattheaxialpositions,forminganelongatedoctahedron.Thecomplexisatwo-dimensionaldistortedrhomboidalnetworkpossessingtwokindsofrhomboidswithdimensionsofca.1.6792nm×0.3203nmand1.2778nm×0.3198nm,respectively.Thetwo-dimensionalnetworksarestackedparallellyoneachotheralongc-axistogiveanextendedthree-dimensionalchannelnetworkwithaninterlayerdistanceofca.0.5030nm.Crystaldata:triclinic,spacegroupP-1,a=1.0253(2)nm,b=1.4501(3)nm,c=0.79715(16)nm,α=97.91(3)°,β=90.99(3)°,γ=85.54(3)°,V=1.1703(4)nm3,Z=2,R=0.0892,wR=0.2451.
简介:SrMoO4nanoplatesweresynthesizedbyafacilereversemicroemulsionmethodatroomtemperature.Energyevolutionofthisinsitugrowthprocesswasmonitoredbymeansofamicrocalorimeter.Asharpexothermicpeakfortheinitialreactionandtwodiscontinuousrelativelyweakexothermicpeaksforthesubsequentcrystalgrowthemergedonthemicrocalorimetricheatflowcurve.Basedontheinsituthermokineticdata,therateconstantsofthenucleationprocessandcrystallizationprocessat298.15Kwerecalculatedtobe4.078×10-3and5.033×10-4s-1,respectively.Thegrowthmechanismandenergyevolutionwereinvestigated.
简介:Theacylationof3-pentanoneenaminewasstudiedandanovelformationof4-pyronesfromβ-diketoneenolesterswasfoundinvolvinganintramolecularO-toC-acylshiftfollowedbycyclization.