简介:Selectivelasermelting(SLM)isoneofthemostpopularadditivemanufacturing(AM)technologiesformetalparts.Slicingresult,especiallyforthedifferentdimensionalslicinggeometryanditstopology,playsanimportantrolebecauseofthethermodynamicbehaviorofmetalpowders.Togetcorrectgeometryandreliabletopology,aslicingstrategyforSLMisproposed.Theunavoidablenumericalerrorcausedbysamplingandgeometrictransformationissuppressedfirstly,accordingtoshiftingthez-coordinateofavertexwithasmallvaluesuchtheshiftedvertexisonaslicingplane.Theresultofvertex-shiftingmakesitpossibletoidentifydifferentgeometricfeaturessuchasskinsurfaces,overhangsurfaces,extremeedgesandvolumetricsolid.Second,fromgeometricprimitivesahierarchyofaxis-alignedboundingboxes(AABBs)isconstructedandusedtospeedupintersectionofslicingplanesagainstsetsoftriangles.Allintersectingsegmentsaregivendifferentsignstodepicttheirgeometricortopologicalinformation.Basedthedifferentsigns,thedifferentdimensionalgeometrythatiseventuallyrepresentedbysimpleandanticlockwiseorientedpolygons,areidentified.Finally,thepolygonsareclassifiedandnestedinamulti-treedatastructuresettoproducecorrecttopologicalrelations.Theresultofdigitalandphysicalexperimentsshowstheproposedslicingstrategyisfeasibleandrobust.
简介:AmoregeneralmodeldescribingPCMclose-contactmeltingoutsideahotsphereisdevelopedwiththeaidofintroducingaparamterαandpresentingasupplementaryequationforthefirsttimeinthispaper.Thegoverningintegral-differentialequationsaresolvedbynumericalmethod.Themelt-filmthicknessvariationalongthesurfaceofsphereisobtainedreasonablyduetotheconsiderationoftheinterfaceshapemoreprecisely,ThecalculationresultesofPecletnumber,heattransferredandpressuredistributionarealsocomparedwiththatinliterature,Themodelpresentedinthispapercandescribethewholeclose-contactregionandthewholecontactmeltingprocess.Close-contactmeltinginsphericalorcylindricalcapsulestowhichthemodelcanbeextendedisalsodiscussedbriefly.
简介:JC/T616-20031ScopeThisstandardspecifiestheclassification,technicalrequirements,testmethod,inspectionrules,marking,packing,transportation,storageandqualitycertificationofhighqualitysilicabricksforglassmeltingfurnace.Thisstandardisapplicabletothepressedhighqualitysilicabrickswithunitweight≥40kgforglassmeltingfurnace.
简介:Wehaveobservedsomekindsofdefectsinunseededrapidzone-melting-recrystallized(RZMR)SifilmsformedwithaRF-inducedgraphitestripheatersystem,usingcross-sectionspecimenelectronmicroscope.Theobserveddefectsaresubgrainboundaries(SGB),dislocationsandmicrotwins.ThemostcommonlyobserveddefectsareSGBwhichformedasaresultofsomeorientationdifferencesbetweenadjacentgrainsduringtheirrapidself-nucleationgrowth.MixedtypeSGBwerefrequentlyobserved,althoughsomepuretiltortwistSGBexistedalsointheSifilms.Therotationangularcomponentaroundtheaxisparalleltoscanningdirectionismuchlargerthanthataroundotheraxes.SGBconsistprimarilyofarraysofdislocationandhavecrystallographicangulardeviationsofonedegreeorless.DuringSifilmcooling,dislocationsandmicrotwinswereformedduetonon-uniformthermalstress.ThecrystallographiccharactersofthedislocationsinSifilmsarethesameasthoseincommonbulkSisinglecrystals.TheirBurgersvectorsareb=a/2<110>.Somedis-locationsrunacrosstheSifilm,andtheamorphousSiO2layersonandunderneaththeSifilmcaneffectivelyblockthedislocationsandpreventthemfromenteringthelayers.MicrotwinswereobservedintheSifilmssometimes,thetwinningplanesbeing{111}.
简介:铁路青蛙钢的微结构进化在不同压力下面团结了用OM,FEGSEM,和TEM被学习。钢的碳化物的团结,谷物尺寸,和形态学上的压力的影响被分析。有在高压力下面的压力和团结的微观结构的钢增加的融化的点不与融化的温度显著地变化,这被发现。试验性的结果分别地证明由完全的equiaxed树突组成的团结的微观结构显著地通过压力的增加被精制,与在3,6,和10GPa下面的大约24,18,和8m的吝啬的树突手臂间距。它被precipitates从像针、菱形的碳化物改变的TEM观察也揭示(M3C)在正常期间形成(大气)压力团结进nodulized六角形猛抛M7在3GPa的C3,和M23在6GPa和10GPa的C6,它与踪迹元素的undercooling和分发被联系。precipitates的直径在80nm和200nm之间。
简介:AnumericalanalysiswascarriedouttostudythemovingboundaryprobleminthephysicalprocessofpulsedNd-YAGlasersurfacemeltingpriortovaporization.Theenthalpymethodwasappliedtosolvethistwo-phaseaxisymmetricalmehingproblem.Computationalresultsoftemperaturefieldswereobtained,whichprovideusefulinformationtopracticallairtreatmentprocessing.Thevalidityofenthalpymethodinsolvingsuchproblemsispresented.
简介:SeismicPvelocitystructureisdeterminedfortheupper500kmoftheinnercoreandlowermost200kmoftheoutercorefromdifferentialtraveltimesandamplituderatios.ResultsconfirmtheexistenceofagloballyuniformFregionofreducedPvelocitygradientinthelowermostoutercore,consistentwithironenrichmentneartheboundaryofasolidifyinginnercore.Pvelocityoftheinnercorebetweenthelongitudes45oEand180oE(quasi-EasternHemisphere)isgreaterthanorequaltothatofanAK135-Freferencemodelwhereasthatbetween180oWand45oE(quasi-WesternHemisphere)islessthanthatofthereferencemodel.Observationofthisheterogeneitytoadepthof550kmbelowtheinnercoreandtheexistenceoftransitionsratherthansharpboundariesbetweenquasi-hemispheresfavoreithernoorveryslowinnercoresuperrotationoroscillationswithrespecttothemantle.DegreeoneseismicheterogeneitymaybebestexplainedbyactiveinnercorefreezingbeneaththeequatorialIndianOceandominatingstructureinthequasi-EasternHemisphereandinnercoremeltingbeneathequatorialPacificdominatingstructureinthequasi-WesternHemisphere.Variationsinwaveformsalsosuggesttheexistenceofsmaller-scale(1to100km)heterogeneity.
简介:Athermalconductionmodelisappliedtospeedupthenumericalanalysisofthetemperaturedistributionandtheweldpoolgeometryoffullpenetrationingastungstenarc(GTA)welding.Withconsideringbothtopandbottomfreesurfacedeformationoffull-penetratedweldpool,three-dimensionalweldpoolwithmeltingfrontandsolidificationfrontispredicted.Weldingexperimentsareconductedtomeasurethemeltingfrontcurvesatthetopsurfaceandthelongitudinalsectionoftheweld.Itshowsthatthepredictedandmeasuredresultsareingoodagreement.
简介:在里面很多地球物理或planetological背景包括地球内部核心,从岩浆海洋结晶的一个硅酸盐披风,或包围可能在很多主神并且农神冰冷的satellitesa对流传热遇到的一种深水oceana状况的冰壳水晶的层在与它的melt的层的接触。允许在一个稳固的层的边界或两个融化/结冰是可能的在层影响传送对流的模式。我们这里学习热传送对流的发作在一粘滞球形的壳与动态地导致了它的边界在也或两个都融化/结冰。这被显示出无尺寸的数字P(为每条边界的)的价值上的每interfacepermeable或impermeabledepends的行为,它是融化/结冰的timescale在上的比率一粘滞松驰timescale。P的小价值对应于可渗透的边界条件,当P的大价值对应于透不过的边界条件时。当也边界描绘的数字P是足够小的时,线性稳定性分析预言半渗透的边界的重要效果:允许边界在也融化/结冰允许更大的规模的出现对流模式。当外部边界是可渗透的时,效果是特别地激烈的,自从1个模式仍然是的度甚至在薄球形的壳的情况中最不稳定。在有可渗透的内部、外部的边界的球形的壳的情况中,最不稳定的模式在稳固的壳的一个全球翻译在于,没有变丑。在有可渗透的外部边界的一个完整的范围的限制,这对应于最近为地球内部核心建议的对流翻译模式。作为可能的申请的另一个例子,我们在假定全球表面下的海洋的存在的恩塞勒达斯冰壳讨论热传送对流的盒子,并且发现融化/结冰能在冰壳在传送对流的模式上有重要效果。
简介:在这研究,(L减水乳酸)(PLLA)一系列monodispersed被戒指洞聚合poly综合与Schiff基础铝催化剂,并且数字一般水准的效果分子的重量(M结晶化和PLLA的融化的行为上的n)被微分扫描热量测定(DSC)和宽角度的X光检查衍射(WAXD)调查。PLLA的全部的结晶化率是M与M-dependent,>18.6kg/mol的n。另外,当PLLA的Mn是18.6kg/mol时,融化的热含量(Hm)显示出最大的价值(87.1J/g),它是最高报导的价值到现在为止。为水晶形成从的变化的批评温度-到形式,在等温的结晶化增加的晶体与M处理n增加。在再热的过程,high-MnPLLA在主导的融化山峰以前表明了一座小exothermal山峰,相应于水晶转变从-到-form,但是low-MnPLLAdidnt表演水晶转变的山峰。这些不同结晶化和融化的行为与不同Mn。
简介:Additionofrareearth(RE)suchasYinthesurfacelayerofgraycastironorNi-basedsuperalloybylasersutfacemeltingwascarriedoutusinga2kWCO2laser.FordeliveringtheelementYtothemetalsurfacedur-inglaserirradiation,severalmethodswereemployed.ItisfoundthatY-containingsurfacemodifiedlayercanhecontrollablyobtainedonsubstrates,agraycastironcanbelasersurface-modifiedwithCr+Al-Ypowderre-sultinginathinlayerofFe-Cr-Al-Yalloysuchas30Fe40Cr27Al3Y.
简介:Thepolyoxometalate-imidazoleionicliquids(POM-ILs)withlowmeltingpointsat94.5and95.5°C,[Cnmim]4[Mo8O26](Cnmim=1-alkyl-3-methylimidazolium,n=12,14),havebeensuccessfullysynthesizedandcharacterizedbyDSC,single-crystalX-raydiffractionandTGA,etc.ThetwoPOM-ILshaverelativelyhighstabilitywithdecomposingtemperatureuptoabout347and344°C,respectively.FurtherphotocatalyticperformancewasmeasuredviathedegradationofrhodamineB(RB)inaqueoussolution.Theexperimentsshowthattheconversionreachedto90%after90minunderUV-lightandthedegradationefficiencydependedonpHvalue,differentdosagesandsoon.Inaddition,thecatalystscanberecycledforseveraltimeswithoutsignificantlossofactivity.
简介:13kindsofironores(6fromAustraliaand7fromBrazil)werestudiedontheirpropertiesconcerningCW(CombinedWater)decomposition,Fe2O3decompositionandsoftening-meltinginairatmospherethroughthecharacterizationmethodofTG-DSC(Thermogravimetry-DifferentialScanningCaloremetry).TheexperimentalresultsoftheAustralianoresandBrazilianoresdifferintermsoftheinitialtemperature,temperaturerangeandendothermicamountofCWdecomposition,andbesides,thecontentofCW.ItisestimatedthatforeverypercentincreaseofCWcontentinsinteringrawmaterial,theextrathermalamountabsorbedintheprocessisabout1.83×104kJ,whichequalstothethermalcapacityof0.625kgofstandardcoalburningupcompletely.AstothedecompositionofFe2O3,theinitialtemperatures,terminaltemperaturesandtemperaturerangesoftheAustralianandBrazilianoresarequiteclose.However,theendothermicamountofFe2O3decompositionofthetwoturnsoutratherdifferent:theendothermiccapacityofFe2O3decompositionoftheAustralianoresisgreaterthanthatoftheBrazilianores.Furthermore,theliquidamountgeneratedinthesoftening-meltingprocessiscloselyrelatedtotheSiO2contentinironore.ThehigherSiO2contenttheorecontains,themoreliquidvolumeitwillgenerateinthesoftening-meltingprocessofironore.
简介:Flyashfromamunicipalsolidwasteincinerator(MSWI)withoutpreprocessing(originalflyash,OFA)wasmeltedbyadirectcurrent(DC)plasmaarcfurnacetoinvestigatehowthefeedformsgovernedtheresults.Dioxinsinfluegasfromstackandbag-filterash(BFA)weredetected.ThedistributionofheavymetalsofPb,Cd,As,andCralongthefluegasprocesssystemwasanalyzed.Throughacomparisonoftheresultsfordioxinsandheavymetalsinthisstudyandpreviouswork,carrying-overofflyashparticleswiththefluegasstreamcanbededuced.BasedonthemagneticinductionequationandNavier-Stokesequations,amagnetohydrodynamic(MHD)modelfortheplasmaarcwasdevelopedtodescribetheparticle-carryingeffect.Theresultsindicatethat,a.whenmelted,thefeedformsofMSWIflyashaffecttheresultssignificantly;b.itisnotpreferabletomeltMSWIflyashdirectly,andeffortsshouldbemadetolimitthemasstransferofOFAfromtheplasmafurnace.