简介:
简介:Amethodofmeasuringtheinteractionsinamultivariablecontrolsys-tem(MVCS)intimedomainisdefinedinthispaper.Anintelligentdecouplingcom-pensatorisdesignedintermsoftheconceptoffuzzycontrol,sothattheauto-tuningofcontrollers’parametersina2×2MVCScanbeturnedintothatoftwoindependentsingle-loopcontrolsystems(SLCS).Themethodpresentedinthepaperhassuccess-fullybeenusedinasimulationexperimentontheautomatictuningofacoordinatedcontrolsystem(CCS)inthedrum-boilerturbogeneratingunit(DBTU)andthesimu-lationresultsaxesatisfactory.
简介:High-temperaturecorrosionisaseriousproblemforthewater-walltubesofboilersusedinthermalpowerplants.Oxidation,sulfidationandmoltensaltcorrosionaremaincorrosionways.Thereinto,themostseverecorrosionoccursinmoltensaltcorrosionenvironment.Materialsrichinoxidesformers,suchaschromiumandaluminum,areneededtoresistcorrosioninhigh-temperatureandcorrosiveenvironment,butprocessabilityofsuchbulkalloysisverylimited.Highvelocityelectricarcspraying(HVAS)technologyisadoptedtoproducecoatingswithhighcorrosionresistance.Bycomparison,NiCr(Ni-45Cr-4Ti)isrecommendedasapromisingalloycoatingforthewater-walltubes,whichcanevenresistmoltensaltcorrosionattack.Inthestudyofcorrosionmechanism,themodernmaterialanalysismethods,suchasscanningelectronmicroscopy(SEM),X-raydiffractometry(XRD)andenergydispersivespectrometry(EDS),areused.ItisfoundthatthecorrosionresistancesofNiCrandFeCrAIcoatingsaremuchbetterthanthatof20gsteel,thattheNiCrcoatingshavethebestanti-corrosionproperties,andthattheNiCrcoatingshaveslightlylowerporesthanFeCrAIcoatings.Itistestifiedthatcorrosionresistanceofcoatingsismainlydeterminedbychromiumcontent,andthemicrostructureofacoatingisasimportantasthechemicalcompositionofthematerial.Inaddition,thefracturemechanismsofcoatingsinthecycleofheatingandcoolingareputforward.Thedifferenceofthethermalphysicalpropertiesbetweencoatingsandbasemetalsresultsinthethermalstressinsidethecoatings.Consequently,thecoatingsspallfromthebasemetal.
简介:摘要:本文首先研究了《牛津高中英语》教材中Word Power板块的教学现状,并提出了运用语义场理论来设计这一板块的教学;接着在阐述这一理论的基础上,结合教学实例说明了在情景化教学设计中如何激活、体验、巩固和活用语义场,即呈现方式多样化、操练方式语境化、情境体验真实化;最后指出了以语义场理论为基础的情境化教学设计是Word Power板块教学的一条有效途径。
简介:摘要:词汇的学习对于英语水平的提高,其重要性不言自明。而译林版教材的word power旨在扩充学生词汇量的同时,提高学生的读写等综合能力。本文以牛津高中英语教材模块三第二单元word power为例在帮助学生扩大知识面的同时,锻炼学生正式英语和非正式英语的应用能力。