学科分类
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4 个结果
  • 简介:CatalystcontainingshapeselectivezeoliteisusedtoinvestigatethecatalyticcrackingcharacteristicsofpalmoilandthreetypesofhydrocarbonVGOsonafixedfluidizedbed(FFB)unit.Theadvantageofproducinglightolefinsandlightaromaticsbycatalyticcrackingofplantoilisdiscussed.Resultsindicatethatthehydrocarbylgroupoftheplantoilmoleculeisquitereadilycrackable;theC6-C8aromaticsyieldiswellaboveandthelightolefinsyieldisaboutthesamewiththehydrocarbonfeeds,whiletheyieldsoflowvalueproductsarelower;thehydrocarbylgroupoftheplantoilmoleculehasstrongtendencyofaromatization,andcanenterthezeoliteporestoselectivelyformC6-C8aromatics;duringcatalyticcrackingofplantoilandfattyacids,aportionoftheoxygenisremovedintheformofwaterthroughhydrogentransferreaction,whileolefinsarepreventedfrombeingsaturated,whichcanensureproperyieldsofbothlow-carbonolefinsandlightaromatics.

  • 标签: plant oil catalytic CRACKING HYDROGEN-TRANSFER LIGHT
  • 简介:Realizationofefficientyellow-light-emittingdiodes(LEDs)hasalwaysbeenachallengeinsolid-statelighting.Greatefforthasbeenmade,butonlyslightadvancementshaveoccurredinthepastfewdecades.AftercomprehensiveworkonInGaN-basedyellowLEDsonSisubstrate,wesuccessfullymadeabreakthroughandpushedthewall-plugefficiencyof565-nm-yellowLEDsto24.3%at20A∕cm~2and33.7%at3A∕cm~2.ThesuccessofyellowLEDscanbecreditedtotheimprovedmaterialqualityandreducedcompressivestrainofInGaNquantumwellsbyaprestrainedlayerandsubstrate,aswellasenhancedholeinjectionbya3DpnjunctionwithV-pits.

  • 标签: INGAN SI EFFICIENT InGaN-based
  • 简介:Background:Identifyingfactorsassociatedwithphysicalactivity(PA)isusefulinplanninginterventionsandpolicies.Theaimofthisstudywastoidentifysociodemographic,biological,andpsychosocialfactorsassociatedwithPAperformedinschoolsettings.Methods:Datacollectedforthepresentstudyincludedgender,age,socioeconomicstatus,bodyfatpercentage,aerobicfitness,self-efficacy,attitudes,peerandparentalsupport,andperceptionofschoolenvironment.Dependentvariableswerelight-intensityPA(LPA)andmoderate-to-vigorousintensityPA(MVPA)performedduringschooltime,recesses,andphysicaleducation(PE)classes.Multipleregressionanalyseswereperformed.Results:Participatingadolescents(n=567,53%female,12.9±5.3years)spent5%ofschooltimeinMVPAand27%inLPA,15%ofrecessesinMVPAand44%inLPA,and16%ofPEclassesinMVPAand41%inLPA.BoysengagedinmoreMVPAinallcategories.AgewasinverselyrelatedwithMVPAandLPAinallperiods,whereasbodyfatpercentagewasinverselyrelatedwithMVPAinschooltimeandPEclasses.AttitudewasinverselyrelatedwithMVPAinallperiodsandwithLPAinrecesses.ConsideringPAtobegoodandenjoyablewaspositivelyassociatedwithMVPAinschooltime.Conclusion:AdolescentsspentlittletimeinPAduringschool.Futureinterventionsshouldimplementenjoyableactivitiesatschool.

  • 标签: ACCELEROMETER Adolescents ATTITUDE Physical education Public