简介:Thebubblesriseupandburstatthefreesurfaceisacomplextwo-phaseprocess.AfreeenergylatticeBoltzmannmethod(LBM)modelisadoptedinthispapertostudythisphenomenon.Theinterfacecapturingtechnique[Zhengetal.,2006]isusedtodealwiththehighdensityratioproblem.TheLaplacelawandtheair-waterinterfacecapturingabilityarevalidatedforthemultiphasemodel.Theinteractionbetweenthesinglebubbleormultiplebubblesandthefreesurfacearestudiedbythemultiphasemodel.Theforceactingonthebubbleandtheevolutionofthefreesurfaceisstudied.Meanwhile,effectoftheinitialdistancebetweentwoadjacentbubblesoninteractioneffectsofmultiplebubblesisinvestigatedaswell.
简介:当在ethanolwater的开始者混合了溶剂,有为播种乳剂聚合要用作种子的375nm的直径的聚苯乙烯(PSt)microspheres用钾persulfate(KPS)经由乳剂聚合被准备。有丙烯腈的苯乙烯(圣)的使乳化免费的播种乳剂copolymerization(一)被执行面对poly(乙烯乙二醇)是的monomethoxymonomethacrylate(PEGm)macromonomer反应stabilizer和2,2-azobisisobutyronitrile(AIBN)是poly获得亚微米大小的PEGm接枝的开始者(styrene-co-acrylonitrile)(PEGm-g-PSAN)合成粒子与唯一的形态学。扫描电子显微镜学(SEM)显示了那圣并且一一起形成不平常的形态学贡献。圣的集中并且一,显著地增加方法的全部的单体集中,开始者类型和单体影响了合成聚合物粒子的形态学。
简介:Inthisstudy,factorsaffectingthecrystalstructureofflame-synthesizedY2O3:Euparticleswereinves-tigated,especiallytheparticlesizeeffectanditsinteractionwithEudopingconcentration.PolydisperseY2O3:Eu(sizerange200nmto3m)powdersampleswithEudopingconcentrationsfrom2.5mol%to25mol%weregeneratedineitherH2/airorH2/O2substrate-freeflames.ThecrystalstructureofthepowdersampleswasdeterminedbypowderX-raydiffraction(XRD),whichwascomplementedbypho-toluminescence(PL)measurements.Singleparticlecrystalstructurewasdeterminedbysingleparticleselectedareaelectrondiffraction(SAED),andforthefirsttime,byelectronbackscatterdiffraction(EBSD).H2/airflamesresultedincubicphaseY2O3:Euparticleswithhollowmorphologyandirregularshapes.ParticlesfromH2/O2flameshaddenseandsphericalmorphology;sampleswithlowerEudopingconcen-trationshadmixedcubic/monoclinicphases;sampleswiththehighestEudopingconcentrationswerephase-puremonoclinic.ForsamplesgeneratedfromH2/O2flames,aparticlesizeeffectanditsinteractionwithEudopingconcentrationwerefound:particlessmallerthanacriticaldiameterhadthemonoclinicphase,andthiscriticaldiameterincreasedwithincreasingEudopingconcentration.Thesefindingssug-gestthattheformationofmonoclinicY2O3:Euisinevitablewhenextremelyhotsubstrate-freeflamesareused,becausetypicalflame-synthesizedY2O3:Euparticlesizesarewellbelowthecriticaldiameter.However,itmaybepossibletogenerateparticleswithdense,sphericalmorphologyandthedesiredcubicstructurebyusingamoderatelyhighflametemperaturethatenablesfastsinteringwithoutmeltingtheparticles.
简介:Aself-adaptiveprecisealgorithminthetimedomainwasemployedtosolve2-Dnonlinearcoupledheatandmoisturetransferproblems.Byexpandingvariablesatadiscretizedtimeinterval,thevariationsofvariablescanbedescribedmoreprecisely,andanonlinearcoupledinitialandboundaryvalueproblemwasconvertedintoaseriesofrecurrentlinearboundaryvalueproblemswhicharesolvedbyFEtechnique.Inthecomputation,noadditionalassumptionandthenonlineariterationarerequired,andacriterionforself-adaptivecomputationisproposedtomaintainsufficientcomputingaccuracyforthechangesizesoftimesteps.Inthenumericalcomparison,thevariationsofmaterialpropertieswithtemperature,moisturecontent,andbothtemperatureandmoisturecontentaretakenintoaccount,respectively.Satisfactoryresultshavebeenobtained,indicatingthattheproposedapproachiscapableofdealingwithcomplexnonlinearproblems.
简介:电影动量和在加速上的薄有限幂定律液体的热运输特征上的内部加热来源的效果不稳定的水平拉长的接口被学习。不同于这块地里的很古典的工作,为改变热电导率的液体电影和概括Fouriers法律的一般表面温度分布被考虑。适当类似转变被用来与一组二点的平常的微分方程(颂诗)把强烈非线性的管理部分微分方程(PDE)变换成一个边界价值问题。在液体电影厚度和摇摆参数之间的通讯在MATLAB用BVP4C节目被导出。自我类似颂诗的数字答案用与一个Runge-Kutta重复程序和牛顿计划相结合的射击技术被获得。液体上的深奥物理参数的效果水平速度和温度分发被介绍并且讨论。
简介:Anewefficientmeshlessmethodbasedontheelement-freeGalerkinmethodisproposedtoanalyzethestaticdeformationofthinandthickplatestructuresinthispaper.Usingthenew3Dshell-likekinematicsinanalogytothesolid-shellconceptofthefiniteelementmethod,discretizationiscarriedoutbythenodeslocatedontheupperandlowersurfacesofthestructures.Theapproximationofallunknownfieldvariablesiscarriedoutbyusingthemovingleastsquares(MLS)approximationschemeinthein-planedirections,whilethelinearinterpolationisappliedthroughthethicknessdirection.Thus,differentboundaryconditionsaredefinedonlyusingdisplacementsandpenaltymethodisusedtoenforcetheessentialboundaryconditions.TheconstrainedGalerkinweakform,whichincorporatesonlydisplacementdegreesoffreedom(d.o.f.s),isderived.Amodified3Dconstitutiverelationshipisadoptedinordertoavoidoreliminatesomeself-lockingeffects.Thenumericefficiencyoftheproposedmeshlessformulationisillustratedbythenumericexamples.
简介:Liquid-solid(L-S)masstransfercoefficients(Ks)werecharacterizedinagas-liquid-solid(G-L-S)three-phasecountercurrentmagneticallystabilizedbed(MSB)usingamorphousalloySRNA-4asthesolidphase.Effectsofsuperficialliquidvelocity,superficialgasvelocity,magneticfieldstrength,liquidviscosityandsurfacetensionwereinvestigated.ExperimentalresultsindicatedthattheexternalmagneticfieldincreasedKsinthree-phaseMSB,ascomparedtothoseinconventionalG-L-Sfluidizedbeds;thatKsincreasedwithmagneticfieldstrength,superficialgasandliquidvelocitiesanddecreasedwithliquidviscosityandsurfacetension;andthatKsshoweduniformaxialandradialdistributionsexceptforsmallincreasesclosetothewall.DimensionlesscorrelationswereestablishedtoestimateKsoftheG-L-ScountercurrentMSBusingSRNA-4catalyst,withanaverageerrorof3.6%.