学科分类
/ 1
6 个结果
  • 简介:Statisticalapproachesforevaluatingcausaleffectsandfordiscoveringcausalnetworksarediscussedinthispaper.Acausalrelationbetweentwovariablesisdifferentfromanassociationorcorrelationbetweenthem.Anassociationmeasurementbetweentwovariablesandmaybechangeddramaticallyfrompositivetonegativebyomittingathirdvariable,whichiscalledYule-Simpsonparadox.WeshalldiscusshowtoevaluatethecausaleffectofatreatmentorexposureonanoutcometoavoidthephenomenaofYule-Simpsonparadox.Surrogatesandintermediatevariablesareoftenusedtoreducemeasurementcostsordurationwhenmeasurementofendpointvariablesisexpensive,inconvenient,infeasibleorunobservableinpractice.Therehavebeenmanycriteriaforsurrogates.However,itispossiblethatforasurrogatesatisfyingthesecriteria,atreatmenthasapositiveeffectonthesurrogate,whichinturnhasapositiveeffectontheoutcome,butthetreatmenthasanegativeeffectontheoutcome,whichiscalledthesurrogateparadox.Weshalldiscusscriteriaforsurrogatestoavoidthephenomenaofthesurrogateparadox.Causalnetworkswhichdescribethecausalrelationshipsamongalargenumberofvariableshavebeenappliedtomanyresearchfields.Itisimportanttodiscoverstructuresofcausalnetworksfromobserveddata.Weproposearecursiveapproachfordiscoveringacausalnetworkinwhichastructurallearningofalargenetworkisdecomposedrecursivelyintolearningofsmallnetworks.Furthertodiscovercausalrelationships,wepresentanactivelearningapproachintermsofexternalinterventionsonsomevariables.Whenwefocusonthecausesofaninterestoutcome,insteadofdiscoveringawholenetwork,weproposealocallearningapproachtodiscoverthesecausesthataffecttheoutcome.

  • 标签:
  • 简介:Therecentrapiddevelopmentsintheautomobileindustryhavedemandedtheextensiveuseofgalvannealed(GA)steelsheets.Inparticular,thedevelopmentoflightweightautomobilesisputtingincreasinglyhigherrequirementsonthestrengthofGAsteelsheets.Thegalvannealfurnace,whichisusedforprocessinggalvannealedsteelsheets,istypicallycomposedoftheinductionheatingsection,holdingsectionandfogcoolingsection.Thispaperdescribedthestructuralcharacteristicsofeachcomponentofthegalvannealfurnace,andanalyzedtemperaturecontrolmethodsofthegalvannealfurnacethatareimportantforthesuccessfulproductionofhigh-strengthGAsteelsheetsforautomotiveapplications.

  • 标签: 温度控制 镀锌炉 镀锌钢板 汽车行业 合金化 感应加热
  • 简介:CO2emissionofthesteelindustrytakesupagreatproportionofthetotalemissionoftheworld.ItisnecessarytoreducetheCO2intensityofsteelproductsinordertosaveenergy,protecttheenvironmentandkeepasustainabledevelopmentinthesteelindustry.Basedontheresearchofsteelproducts'lifecycleinventory,thosewhoconductedthisresearchhavefocusedontheanalysisofCO2emissionfactorsandmeasures.Adoptingthelifecycleinventorymodelofacertainsteelmakingsite,togetherwiththeTornadoChart,theresearchershaveidentifiedsignificantfactors,providedsomeexplanation,andsuggestedsomepossiblemeasurestoreduceCO2emission.TheresultshaveshownthatthemostimportantfactorsaretheCO2intensityofblastfurnacegas(BFG),hotmetalratioofbasicoxygenfurnace(BOF)andthematerialutilizationefficiency.Accordingly,somemeasuressuchasremovingCO2inBFG,decreasingthehotmetalproportioninBOF,andimprovematerialutilizationefficiencyineachprocess,maybetakentodecreaseCO2emission.

  • 标签: CO2排放量 缓解方法 二氧化碳排放量 钢铁厂 生命周期清单 碱性氧气转炉
  • 简介:Inthispaper,aspiralmagneticfieldelectromagneticstirrer,whichcanseparatelyinducetwodifferentmagneticfields,isintroduced.Thecorrespondingcentralmagneticfluxcurvesofthestirrerweremeasuredbytwodif

  • 标签:
  • 简介:网状渗碳体的组织结构是影响C86DA帘线钢盘条拉拔断丝的主要原因。为了能够有效的解决成品盘条网状渗碳体的形成概率降低下游客户拉拔断丝频次,本文主要从网状渗碳体的形成原因入手抓住轧钢工序中可控点,在原有工艺的基础上把加热二段温度提高10℃,均热段提高20℃,加热时间保证在120min以上,2#和3#风机增加10%的开度。结果表明,通过关键参数的调整有效地减轻了C86DA网状渗碳体的形成,达到了下游客户的使用要求。

  • 标签: C86DA盘条 加热温度 加热时间 网状渗碳体 控冷
  • 简介:La1.5Mg17Ni0.5hydrogenstoragematerialswerepreparedbyhydridingcombustionsynthesis(HCS)andmechanicalalloying(MA)methodrespectively.TheexperimentalresultsshowthatthehydrogenabsorptionpropertiesofLa1.5Mg17Nio.5preparedbyMAarebetterthanthatbyHCS.La1.5Mg17Nio.5preparedbyMAcanabsorb6.73mass%hydrogenat523Kwithin1min,and4.92mass%hydrogenat423K.TheimprovementofhydridingpropertiesofLa1.5Mg17Ni0.5alloypreparedbyMAcanbeascribedtotheformationofnano-crystallineanddefectsduringthemechanicalalloying.

  • 标签: HYDRIDING COMBUSTION synthesis mechanical ALLOYING hydrogen