简介:Meso-scalestructuresexistingintheformofparticle-richclusters,streamersorstrandsincirculatingfluidizedbeds,andofascendingbubbleplumesanddescendingliquid-richvorticesinbubblecolumnsandslurry-bedreactors,ascommonlyobserved,haveplayedanimportantroleinthemacro-scalebehaviorofparticle-fluidsystems.Thesemeso-scalestructuresspanawiderangeoflengthandtimescales,andtheirorigin,evolutionandinfluencearestillfarfrombeingwellunderstood.Recentdecadeshavewitnessedtheemergenceofcomputersimulationofparticle-fluidsystemsbasedoncomputa-ionalfluiddynamic(CFD)models.However,strictlyspeakingthesemodelsarefarfrommatureandthecomplexnatureofparticle-fluidsystemsarisingfromthemeso-scalestructureshasbeenposinggreatchallengestoinvestigators.Thereasonmaybethatthecurrenttwo-fluidmodels(TFM)arederivedeitherfromcontinuummechanicsbyusingdifferentkindsofaveragingtechniquesfortheconservationequationsofsingle-phaseflow,orfromthekinetictheoryofgasesinwhichtheassumptionofmolecularchaosisemployed,therebylosingsightofthemeso-scaleheterogeneityatthescaleofcomputationalcellsandleadingtoinaccuratecalculationoftheinteractionforcebetweenparticlesandfluids.Forexample,theoveralldragforceforparticlesinacellisusuallycalculatedfromtheempiricalWen&Yu/Erguncorrelations,whichshouldbesuspectedsincethesecorrelationswereoriginallyderivedfromhomogeneoussystems.Schemestosolvethisproblemforgas-particlessystemsmaybeclassifiedintofourcategories.First,onecouldcapturethedetailedmeso-scalestructureinformationatthecellscalebyemployingtheso-calleddirectnumericalsimulation(DNS)(Hu,1996),thepseudo-particlemodeling(PPM)(Ge&Li,2003),ortheLattice-Boltzmannmethod(LBM)totracktheinterfacebetweengasandparticles.Second,refinementofthecomputationalmeshesmayreducetheheterogeneitytosomeextentandmaybe
简介:Theeffectsofdifferentconvectiveparameterization,explicitmoistureschemesandsurfaceheat-ingonthemeso-βscalestructureofasqualllinesystemareinvestigated,byusinganimprovedmesoscalemodel.Itisfoundthatthesuccessfulpredictionofmesoscaleconvectivesystemshingesup-onnotonlythesub-gridscaleconvection,butalsotheresolvablescalephasechangeprocessesandthediurnalvariationintheboundarylayer.ThesimultaneousoperationoftheFritsch-Chappellconvectiveschemewithparameterizedmoistdowndraftsandtheprognosticequationsforcloudwater(ice)andrainwater(snow)seemstobeessentialinsimulatingrealisticallyMCSsandreducingoreliminatingtheunrealisticdevelopmentoftheCISK-likeinstabilityassociatedwiththesqualllinesystem.
简介:Inthispaper,timeandspacedistributionregularityofmeso-scaleheavyrainsinfiveselectedtyphoonswhichlandedatFujianfrom1996to1998hasbeenanalyzed.Besides,withhourlydigitizedsatelliteinfraredimagery,thefeaturesofthemesoscalearerevealedforthegenesisandevolutionofmesoscaleconvectivesystemsintyphoons.Itindicatesthattheintensityofmesoscalestormsiscloselyconnectedwiththetemperatureandtheareaofthecoldestcloudcluster.Theheavyrainfallusuallyemergesontheeasternsideofthemesoscaleconvectivecloudclusters,wherethecloudmassisdevelopingandwithadensegradientandbigcurvatureofisolineofthecloudtoptemperature.
简介:Longtermmorphologicalsimulationsusingcompletecoupledmodelsleadtoverytimeconsumingcomputations.Latteux(1995)presentedmodellingtechniquesdevelopedfortidalcurrentsituationsinordertoreducethecomputationaleffort.Inthispapertheapplicabilityofsuchmethodstosmallscaleproblemsisinvestigated.Itispointedoutthatthesemethodscanbetransferredtosmallscaleproblemsusingtheperiodicityofthevortexsheddingprocess.
简介:Frommethylpyropheophorbide-a(MPPa,1),thevinylgroupofmethylpyropheophorbide-awasconvertedintoalkylcarbonylgroupbyGrignardreactionandoxidizationtogivechlorins2,3and5.TheVilsmeierreactionofnickel3-substituent-3-devinylpyropheophorbide-a(6),whichwaspreparedbythemetallationwithnickelacetate,with3-dimethylamino-acrolein/phosphorylchloride(3-DMA/POCl3)wascarriedouttogiveδ-meso-formylvinylpyropheophorbide-a(7)ingoodyield.Thebenzoisobacterichlorin(8)wasobtainedbythetreatmentof7bwithconcentratedsulfuricacid.
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简介:ChineseGymnastsScaleNewHeightsDeligencehasitsrewards,theChineseteamdiscovers.THECHENESENationalGymnasticsTeamhaditsbestperfor...
简介:合金(SMA)电线增强了的形状存储器的机械行为疼痛有损坏的结构通过变化原则被分析,为中央排水量域的为结构的一个管理方程被导出的、数学表达式,有损坏的典型元素的压力紧张地被介绍,并且为在SMA电线和矩阵之间的接口失败的一个失败标准在死了负担的二种使活动和温度下面被建立,在温度在有效免费恢复被包括的地方,拉紧。另外,在象接口性质那样的失败标准有一些另外的创作因素,SMA的动态性质,起始的debonding长度L-l等等。结果是重要的理解自我改编的控制和SMA电线的失败机制增强了的结构的力量有损坏的聪明的结构。
简介:Acombinedmethodofdensityfunctionaltheory(DFT)andstatisticsintegralequation(SIE)forthedeterminationoftheporesizedistribution(PSD)isdevelopedbasedontheexperimentaladsorptiondataofnitrogenonactivatedmesocarbonmicrobead(AMCMB)at77K.TheporesofAMCMBaredescribedasslit-shapedwithPSD.BasedonthePSD,methaneadsorptionandphasebehaviorarestudiedbytheDFTmethod.BothnitrogenandmethanemoleculesaremodeledasLennard-Jonessphericalmolecules,andthewell-knownSteele's10-4-3potentialisusedtorepresenttheinteractionbetweenthefluidmoleculeandthesolidwall.InordertotestthecombinedmethodandthePSDmodel,theIntelligentGravimetricAnalyzer(IGA-003)wasusedtomeasuretheadsorptionofmethaneontheAMCMB.TheDFTresultsareingoodagreementwiththeexperimentaldata.Basedonthesefacts,wepredicttheadsorptionamountofmethane,whichcanreach32.3ωat299Kand4MPa.TheresultsindicatethattheAMCMBsareagoodcandidateforadsorptivestorageofmethaneandnaturalgas.Inaddition,thecapillarycondensationandhysteresisphenomenonofmethanearealsoobservedat74.05K.
简介:IntroductionThesynthesesandcharacterizationofporphyrinsandmetalloporphyrinshavebeenstudiedextensively[1].Hemoglobin,myoglobinorcytochromeP450,hasbeenappliedasamodelcompound[2].WongC.P.etal.[3]synthesizedthefirstlanthanideporphyrin,acetylacetonatetetraphenylporphyrineuropium,in1974.
简介:Describedisanewtechniqueofdecade-scaleclimaticforecasting,presentedbyacombinationofwaveletanalysisandstochasticdynamics.ThetechniqueisalsoappliedtodiagnosingandforecastingthedurationtimeofdryandwetclimatesinthedecadalhierarchyofdifferentareasinChina.Resultsshowthatinthedecadalhierarchy,thenorth,southwest,andsoutheastofChinaareareaswherevariouskindsoffrequentclimatedisastersappear;droughtseasilyoccurinthenorthandnorthwest,whilefloodsoftenoccurinSouthChina.Becausethismodelingtechniqueisbasedontimeseriesdata,itcanalsobeappliedinthemodelingandforecastingofsuchtimeseriesashydrology,earthquakesandecology.
简介:A5-yearexperimentonwaterbalancehasbeenconductedinaflatrainfedwheatfieldwithanareaof66×100m^2inFengqiu,HenanProvinceinChina.Basedontheanalysisofsemi-variancefunctionsconductedwithsoilmoisturesamplestakenfrom77nodesofa10×10m^2grid,thesoilmoisturedistributioninthefieldwasstructuralwithatemporalstability.Accordingtotheautocorrelationrangeofthesemi-variancefunction,6siteswereselectedforthedeterminationofsoilwaterconditions.Thecharacteristicofprobabilitydensityfunctionofthedifferencesofwaterstorageintwosetsofmeasurementsshowedthatthedistributionofthesevariablesinthefieldwasanormalone.Theerrorintheestimationoftheaverageof5randomsampleswas14%(α=0.10),andtheerrorsofwaterconsumptionbywheatduringtheexperimentswereestimatedtobe6-13%.Simetheexperimentalfieldwaslargeenoughtoavoidanyedgeeffect,theresultsobtainedshouldtallywiththeactualsituation.Yetthesoilsystemwasheterogeneous,sowemustfollowtheprinciplesofstatisticsandgeostatisticswhendescribingthesystem'sstatuswiththeaverageofthesamples.
简介:Aclassoflarge-sealesystems,wheretheoverallobjectivefunctionisanonlinearfunctionofperformanceindexofeachsubsystem,isinvestigatedinthispaper.Thistypeoflarge-scalecontrolproblemisnon-separableinthesenseofconventionalhierarchicalcontrol.Hierarchicalcontrolisextendedinthepapertolarge-scalenon-separablecontrolproblems,wheremultiobjectiveoptimizationisusedasseparationstrategy.Thelarge-scalenon-separablecontrolproblemisembedded,under;ertainconditions,intoafamilyoftheweightedLagrangianformulation.TheweightedLagrangianformulationisseparablewithrespecttosubsystemsandcanbeeffectivelysolvedusingtheinteractionbalanceapproachatthetwolowerlevelsintheproposedthree-levelsolutionstructure.Atthethirdlevel,theweightingvectorfortheweightedLagrangianformulationisadjustediterativelytosearchtheoptimalweightingvectorwithwhichtheoptimaloftheoriginallarge-scalenon-separablecontrolproblemisobtained.Theoreticalbaseofthealgorithmisestablished.Simulationshowsthatthealgorithmiseffective.
简介:TheconstructionoftheGeologicTimeScale(GTS)isatitanicscientificchallengethathasbeenunderwayfortwocenturiesandwillrequiremuchdedicatedeffortinthefuture.ItalypreservesaparamountstratigraphicrecordofMesozoicandCenozoicmarinesedimentsthathavebeensignificantinthedevelopmentofthemodernGTS.TheItalianstratigraphicrecordhasbeenhistori-callyimportantinintroducinganddefiningthestandardChronostratigraphicUnits(CUs)oftheNeogeneandQuaternary.PelagicsuccessionsfromNorthernApen-ninesandSouthernAlpshavebeenusedintheseventiesforintegratingthelateCretaceous-PaleogeneGeomag-neticPolarityTimeScale(GPTS)withplanktonicmicrofossilbiostratieraohvandstandardCUs.Thiswasamajorcontributiontotheconstructionofanewgener-ationofGTSbasedonintegratedmagnetobiochronol-ogy.ThemiddleMiocenetoearlyPleistocenemarinerecordfromSicilyandsouthernItalyhasbeenfunda-mentalforestablishingtherecentlydevelopedAstro-nomicalTimeScale(ATS).Inprospect,therearemanypotentialsstilltobeexploitedintheItalianmarinestratigraphicrecordforimplementingtheGTSbydefin-ingGSSPsofvariousCUs,improvingmagneto-biochronologyandextendingdownwardstheATS.