学科分类
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274 个结果
  • 简介:Theeffectsofisothermalholdingprocessonthemicrostructureevolutionofsemi-solid7075strengthaluminumalloyproducedbytherecrystallisationandpartialremelting(RAP)processwereinvestigated.Tensilemechanicalpropertiesofas-receivedandthixoformedalloysatroomtemperaturewereexamined.Theresultsshowthatthemicrostructureofas-receivedalloyexhibitsremarkableorientationalongthedeformationdirection.Withtheincreaseofisothermalholdingtime,thesolidparticlegrainsizecontinuouslyincreasesandthedegreeofspheroidizationalsoimproves.Coalescencemechanismisdominantwhenreheatedat595°CandOstwaldripeningmechanismisdominantwhenreheatedat615°Cinthesemi-solidstate.Alowercoarseningrateisobservedfor615°C(coarseningrateK=391μm3s-1)comparedwiththecoarseningratefor595°C(coarseningrateK=501μm3s-1).TheRAP7075aluminumalloycanbesuccessfullythixoformedandthefillingofcomponentsisgoodafterthixoforming.Thethixoformedcomponentsexhibitfavoritemechanicalproperties.

  • 标签: 7075 High strength ALUMINUM alloy SPHEROIDAL
  • 简介:CSIR-RCS的灵活性,与使过程凉下来的同时的空气激动人心的正式就职,在有高压力的联合死扔被在广告2024,6082和7075上执行的盘子的半固体rheocasting成功地表明做铝合金。张力的性质为在T6的铝合金调节的做的上述提及的rheocast被测量。结果证明张力的性质接近了或甚至在一些情况中超过了最小的说明。rheocast2024-T6的收益力量和延伸超过了最小的要求做处于T6条件的合金但是因为开始的合金的Mg内容在商业合金说明下面,最终的张力的力量仅仅完成了90%说明。rheocast6082-T6的力量超过了所有做合金T6力量目标但是延伸仅仅由于孔管理了36%要求的最小,由在好金属间化合的针的答案热处理,和存在期间的早期的融化在引起了最容易溶解。7075超过了的rheocast的收益力量要求的和最终的张力的力量也管理了97%说明;当延伸仅仅由于在解决方案热处理进程期间引起的早期的融化的孔也到达了46%最小的要求时。

  • 标签: 锻铝合金 流变成形 半固态 形状 治疗 屈服强度
  • 简介:Dynamicfluid-solidinteractionsarewidelyfoundinchemicalengineering,suchasinparticle-ladenflows,whichusuallycontaincomplexmovingboundaries.Theimmersedboundarymethod(IBM)isaconvenientapproachtohandlefluid-solidinteractionswithcomplexgeometries.Inthiswork,Uhlmann’sdirect-forcingIBMisimprovedandimplementedonasupercomputerwithCPU-GPUhybridarchitecture.Thedirect-forcingIBMismodifiedasfollows:thePoisson’sequationforpressureissolvedbeforeevaluationofthebodyforce,andtheforceisonlydistributedtotheCartesiangridsinsidetheimmersedboundary.Amultidirectforcingschemeisusedtoevaluatethebodyforce.Thesemodificationsresultinadivergence-freeflowfieldinthefluiddomainandtheno-slipboundaryconditionattheimmersedboundarysimultaneously.Thismethodisimplementedinanexplicitfinite-differencefractional-stepscheme,andvalidatedby2Dsimulationsoflid-drivencavityflow,Couetteflowbetweentwoconcentriccylindersandflowoveracircularcylinder.Finally,themethodisusedtosimulatethesedimentationoftwocircularparticlesinachannel.Theresultsagreeverywellwithpreviousexperimentalandnumericaldata,andaremoreaccuratethantheconventionaldirect-forcingmethod,especiallyinthevicinityofamovingboundary.

  • 标签: 相互作用 二维模拟 边界法 浸入 固体 流体
  • 简介:扔的near-liquidus准备的6061件半固体铝合金化工物品借助于Gleeble-3500热机械的模拟器处于半固体状态被压缩。在在不同温度和紧张率的真压力和真紧张之间的关系与70%的变丑度被学习。微观结构在变丑过程期间被描绘。半固体合金的变丑机制和形成thixo性质被分析。结果证明同类并且6061Al合金由扔技术的near-liquidus生产了的半固体的非树突微观结构能与对与通过再热的最容易溶解的作文在球形附近的谷物和液体阶段镇静的形成thixo合适的微观结构被转变成半固体状态过程。变丑温度和紧张率显著地影响山峰压力而非稳定流动应力。到处于半固体状态的变丑的抵抗随变丑温度的增加和紧张率的减少减少。在稳定的thixotropic变丑舞台,thixotropic性质是一致的,并且主要变丑机制是在稳固的粒子和稳固的粒子的塑料变丑之间旋转或滑动。

  • 标签: 半固态铝合金 6061铝合金 变形机制 成形性能 压缩 热模拟实验机
  • 简介:Thewaterintakeheadinstalledwithinclinedboardingsiscalledlaminatesedimentprecipitation,whichseparatesliquidandsolidparticlesintwo-phaseflowbygravity.ThepaperpresentstheequationsforcalculatingthedistanceHbetweentwoincllinedboardings,indicatingthatHhasakeyeffectontheparticleprecipitationvelocityV2.Thepaperfocusesalsoonthecal-culationofhydraulicsimilarityofmodelwiththetheoreticmodel.

  • 标签: SEDIMENT REYNOLDS number water INTAKE head
  • 简介:在一系列分子动力学计算中,(KI)108离子簇冷却时自发地由液相变为立方面心相.在350K和400K的成核速率大于1036核/m3·s.由成核速率得到的固-液界面自由能约为50mJ/m2.

  • 标签: 分子动力学模拟 成核速率 KI离子簇 相变
  • 简介:【摘 要】非标自动化设备定制是一种需要根据用户需求定制设备的供应模式,该模式往往没有既有的模型和数据作为基础支持,需要根据用户的需求不断调整设计数据,双方不断达成沟通,最终完成设计生产。非标自动化设备供应涉及到大量的数据交互和责权划分等问题,传统的信息交互模式存在较多的弊端,对此,在非标自动化设备行业中应用SOLID WORKS PDM系统便有了很好的基础空间。

  • 标签: SOLID WORKS PDM 非标自动化 设备定制 项目管理
  • 简介:Densegas-particleflowsareencounteredinavarietyofindustriallyimportantprocessesforlargescaleproductionoffuels,fertilizersandbasechemicals.Thescale-upoftheseprocessesisoftenproblematicandisrelatedtotheintrinsiccomplexitiesoftheseflowswhichareunfortunatelynotyetfullyunderstooddespitesignificanteffortsmadeinbothacademicandindustrialresearchlaboratories.Indensegas-particleflowsboth(effective)fluid-particleand(dissipative)particle-particleinteractionsneedtobeaccountedforbecausethesephenomenatoalargeextentgoverntheprevailingflowphenomena,i.e.theformationandevolutionofheterogeneousstructures.Thesestructureshavesignificantimpactonthequalityofthegas-solidcontactandasadirectconsequencethereofstronglyaffecttheperformanceoftheprocess.Duetotheinherentcomplexityofdensegas-particlesflows,wehaveadoptedamulti-scalemodelingapproachinwhichbothfluid-particleandparticle-particleinteractionscanbeproperlyaccountedfor.Theideaisessentiallythatfundamentalmodels,takingintoaccounttherelevantdetailsoffluid-particle(latticeBoltzmannmodel)andparticle-particle(discreteparticlemodel)interactions,areusedtodevelopclosurelawstofeedcontinuummodelswhichcanbeusedtocomputetheflowstructuresonamuchlarger(industrial)scale.Ourmulti-scaleapproach(seeFig.1)involvesthelatticeBoltzmannmodel,thediscreteparticlemodel,thecontinuummodelbasedonthekinetictheoryofgranularflowandthediscretebubblemodel.Inthispaperwegiveanoverviewofthemulti-scalemodelingstrategy,accompaniedbyillustrativecomputationalresultsforbubbleformation.Inaddition,areaswhichneedsubstantialfurtherattentionwillbehighlighted.

  • 标签: 致密气-固流 多尺度建模 气-流化床 分子运动
  • 简介:Endoscopicultrasonography-guidedfine-needleaspiration(EUS-FNA)hasbeenappliedtopancreaticobiliarylesionssincethe1990sandisinwidespreadusethroughouttheworldtoday.Weusedthismethodtoconfirmthepathologicalevidenceofthepancreaticobiliarylesionsandtoperformsuitabletherapies.ComplicationsofEUS-FNAarequiterare,butsomeofthemaresevere.OperatorsshouldmasterconventionalEUSobservationandexperienceaminimumof20-30casesofsupervisedEUS-FNAonnon-pancreaticandpancreaticlesionsbeforeattemptingsoloEUSFNA.StudiesconductedonpancreaticobiliaryEUSFNAhavefocusedonselectionofsuitableinstruments(e.g.,needleselection)andsamplingtechniques(e.g.,fanningmethod,suctionlevel,withorwithoutastylet,optimumnumberofpasses).Today,thediagnosticabilityofEUS-FNAisstillimproving;thedetectionofpancreaticcancer(PC)currentlyhasasensitivityof90%-95%andspecificityof95%-100%.InadditiontoPC,avarietyofrarepancreatictumorscanbediscriminatedbyconductingimmunohistochemistryontheFNAmaterials.Aflexible,largecaliberneedlehasbeenusedtoobtainalargepieceoftissue,whichcanprovidesufficienthistologicalinformationtobehelpfulinclassifyingbenignpancreaticlesions.EUSFNAcansupplyhighdiagnosticyieldsevenforbiliarylesionsorperi-pancreaticobiliarylymphnodes.ThisreviewfocusesontheclinicalaspectsofEUS-FNAinthepancreaticobiliaryfield,withtheaimofprovidinginformationthatcanenablemoreaccurateandefficientdiagnosis.

  • 标签: ENDOSCOPIC ultrasonography-guided fineneedleaspiration DIAGNOSIS Pancreaticobiliary PANCREATIC
  • 简介:Experimentswereconductedtoinvestigatetheeffectofaddingfinesonthetribo-chargingofcoarseglassbeads.Fourtypesoffines,i.e.,copper,stainlesssteel,uncoatedandsilver-coatedfineglassbeads,mixedw让h240-830μmglassbeadswereconveyedbyairthroughastainless-steelspiralpipeactingasatribo-charger.Regardlessofthetypeorelectricalconductivityofthefineparticlestested,addingsmallamountsoffines(upto10wt%)tocoarseglassbeadsresultedinasharpincreaseinthemassandsurfacechargedensitiesoftheparticles.Ingeneral,theprofilesofthemassandsurfacechargedensidesofthefine-coarseparticlemixturesasafunctionofthemixturecompositionweredeterminedbytherelativemagnitudeofcontactpotentialdifferencesandthetotalsurfaceareasofallthecomponents.Thedominantparticletribo-electrificationmechanismswitchedfromcoarseparticle-wallcontactstofineparticle-wallcontactswhenthefinesweightpercentageinthemixtureexceeded10%.Amodelwasdevelopedtopredictthemasschargedensityofbinarymixturesasafunctionofthemixturecomposition.

  • 标签: Tribo-charging ELECTROSTATICS FINE particles BINARY MIXTURE
  • 简介:EthylN-cyanomethytbenzenecarboximidatereactedwithaliphaticaldehydesunderthesolid-liquidPTCconditiontogirea-ethoxyphenylmethylene-aminoacrylonitrilederivativesandoxazolinederivatives.Itisaconvenientandnewmethodforsynthesisofβ,β’-dihyroxy-a-aminoacidsbyhydrolysisoftheoxazolinederivatives.

  • 标签: HYDROLYSIS ETHYL SOLID aromatic ALDEHYDES condensation
  • 简介:Thepresentpaperdescribesthestatisticalmodelingandoptimizationofamultistagegas-solidfluidizedbedreactorforthecontrolofhazardouspollutantsinfluegas.Inthiswork,westudythehydrodynamicsofthepressuredropandminimumfluidizationvelocity.Thehydrodynamicsofathree-stagefluidizedbedarethencomparedwiththoseforasingle-stageunit.Itisobservedthatthetotalpressuredropoverallstagesofthethree-stagefluidizedbedislessthanthatofanidenticalsingle-stagesystem.However,theminimumfluidizationvelocityishigherinthesingle-stageunit.Underidenticalconditions,theminimumfluidizationvelocityishighestinthetopbed,andlowestinthebottombed.Thissignifiesthatthebehaviorofsolidschangesfromawell-mixedflowtoaplug-flow,withintermediatebehaviorinthemiddlebed.

  • 标签: 气固流化床 污染物控制 统计建模 优化 多级 烟气
  • 简介:Wedevelopatheoreticalmodelforpredictingtheultrasonicattenuationintheliquid-solidsystemcontainingmixedparticles.Theultrasonicattenuationcoefficientisobtainedbycountingthenumberofphononsthatreachthereceiver.UsingtheMonteCarlomethod(MCM),numericalsimulationswereperformedtopredicttheultrasonicattenuationswithnotonlyasingleparticletypebutalsomonodisperseandpolydispersemixedparticles.Thesimulationresultsforthesystemswithasingleparticletypewerecomparedwithvariousstandardmodels.Theresultsshowthattheyagreewellatrelativelylowparticlevolumeconcentrations(within10%).Forsystemswithmixedparticles,theparticlevolumeconcentrationwasfoundtoincreasetoaround10%,andthevariationoftheultrasonicattenuationagainstthemixingratioyieldsanonlineartrend.Moreover,theultrasonicattenuationissignificantlyaffectedbyparticleproperties.Thenumericalresultsalsoshowthatboththeparticletypeandparticlesizedistributionshouldbecarefullytakenintoaccountinthedispersionswithpolydispersemixedparticles,wheretheMCMcangiveamoredirectdescriptionofthephysicsofsoundpropagationcomparedwiththeconventionalmodels.

  • 标签: ULTRASOUND ULTRASONIC ATTENUATION Monte Carlo method
  • 简介:Quasi-solid-statedye-sensitizedsolarcells(DSCs)werepreparedusinggelelectrolytegelatedbypoly(ethylene-oxide)(PEO)withdifferentmolecularweight.WiththeincreaseinPEOmolecularweight,theshortcircuitcurrentdensities(Jsc)increasesignificantly,whichisrelatedtotheincreaseinI-diffusionduetotheincreaseinfreevolumeofgelelectrolyte.However,onlyaslightincreaseinopenvoltage(Voc)isobserved,whichisexplainedbythedecreaseindarkcurrentarisingfromthereductionoftriiodide(I3-)byconductionbandelectrons.

  • 标签: 聚氧化乙烯 太阳能电池 染料敏化 准固态 电池性能 分子质量
  • 简介:Wepresentthesolidmodeleditdistance(SMED),apowerfulandflexibleparadigmforexploitingshapesimilaritiesamongstCADmodels.ItisdesignedtomeasurethemagnitudeofdistortionsbetweentwoCADmodelsinboundaryrepresentation(B-rep).Wegivetheformaldefinitionbyanalogywithgrapheditdistance,oneofthemostpopulargraphmatchingmethods.Toavoidtheexpensivecomputationalcostpotentiallycausedbyexactcomputation,anapproximateprocedurebasedonthealignmentoflocalstructuresetsisprovidedinaddition.Inordertoverifytheflexibility,wemakeintensiveinvestigationsonthreetypicalapplicationsinmanufacturingindustry,anddescribehowourmethodcanbeadaptedtomeetthevariousrequirements.Furthermore,amultilevelmethodisproposedtomakefurtherimprovementsofthepresentedalgorithmonbotheffectivenessandefficiency,inwhichthemodelsarehierarchicallysegmentedintotheconfigurationsoffeatures.ExperimentresultsshowthatSMEDservesasareasonablemeasurementofshapesimilarityforCADmodels,andtheproposedapproachprovidesremarkableperformanceonareal-worldCADmodeldatabase.

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