简介:3-DevolutionofKarmanvortexfilamentsandvortexfilamentsinbraidregionsintheturbulentwakeofa2-Dcirculaxcylinderisinvestigatednumeri-callybasedoninviscidvortexdynamicsbyanalyzingtheresponseoftheinitially2-Dspanwisevortexfilamentstoperiodicspanwisedisturbanceofvaryingmagnitude,wavelengthandinitialphaseangles.Ourresultsrevealakindof3-Dvortexsysteminthewakewhichconsistsoflargescalehorseshoe-shapedvorticesandsmallscaleλ-shapedvortexfilamentsaswellasvortexloops.Themechanismandthedynamicprocessaboutthegenerationofstreamwisevorticalstructureandthe3-Dcoherentstructurearereported.
简介:Reactionsofthe6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrilederivative1withα-halo-carbonylcompoundsgavetheortho-substitutedintermediates2a-cwhichwereconvertedintofuro[2,3-b]thiopyrano[4,3-d]pyridines3a-cbyfusionofafuranmoietyunderbasicconditions.Furthercyclizationof3a-cledtoafusionofapyrimidinering,yieldingthetetracyclicproducts6,7and8.Inaddition,condensationof6withvariousaromaticaldehydesaffordedthecorrespondingimines9a,b.Mannichreactionof7gaveproducts10a,b.
简介:这研究针对使用片3-D优化到在高度的高通过流动扇子/增强软件的角落流动绕过的控制比率广告扇涡轮引擎。二种片3-D优化,弯曲结束并且鞠躬,上被集中。由于各自的操作模式和环境,3-D的途径转子片的空气动力学的建模与定子翼不同。为转子基于角落流动和紧张问题的考虑的机制的理解,这份报纸使用许多片3-D优化途径例如装载分发优化,离开角度的不安和栈轴操作,它分别地对转子和定子合适。获得的3-D片和翼能改进角落流动特征由弯曲结束并且鞠躬效果。流动在扇子/增强软件的角落的这学习表演的结果例如增强软件的翼的扇子中心区域,尖端和中心,由3-D效果很复杂、统治。在那里的第二等的流动被发现在压缩机表演上有强壮的有害效果。效果弯曲结束并且鞠躬能在角落改进流动分离,但是他们工作的特定的方法和申请范围是有点不同的。经由片3-D优化重新设计片控制角落流动有效地减少了损失产生并且由大数量改进了货摊边缘。
简介:<正>Westudythenonlineardynamicsoftwo-componentBose-Einsteincondensatesinone-dimensionalpe-riodicopticallatticepotentials.Thestationarystateperturbationsolutionsofthecoupledtwo-componentnonlinearSchr?dinger/Gross-Pitaevskiiequationsareconstructedbyusingthedirectperturbationmethod.Theoreticalanalysisrevelsthattheperturbationsolutionisthechaoticone,whichindicatestheexistenceofchaosandchaoticregioninparameterspace.Thecorrespondingnumericalcalculationresultsagreewellwiththeanalyticalresults.Byapplyingthechaoticperturbationsolution,wedemonstratetheatomicspatialpopulationandtheenergydistributionofthesystemarechaoticgenerally.
简介:Two-dimensional(2D)materialshavebeendemonstratedtoexhibituniquepropertiesoriginatingfromits2Dnature.Inrecentyears,theconstructionof2Dmaterialshasbecomeatopicofgreatinterest.Thisarticlesummarizestherecentadvanceof2Dsupramolecularorganicframeworks(SOFs)whicharehomogeneouslyconstructedinsolutionphasethroughself-assemblyofrationallydesignedbuildingblocks.These2DSOFsaresolubleandstillmaintainstablenetworkstructuresinsolutions,whichexhibituniquenessnotonlyinstructuresbutalsoinproperties.Inthisconcisereview,theSOFs-relatedbackgroundisbrieflyintroducedfirstly,followedbyoutliningtheresearchprogressofsoluble2DSOFsfromtheperspectiveofmonomerdesign,assembly,andstructuralcharacterization.Thearticleendswithapersonaloutlookonthefuturedevelopmentofthisnewclassofsupramolecularpolymers.
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:Fortwo-dimensionnonlinearconvectiondiffusionequation,atwo-gridmethodofcharacteristicsfinite-elementsolutionwasconstructed.Inthismethodthenonlineariterationsisonlytoexecuteonthecoarsegridandthefine-gridsolutioncanbeobtainedinasinglelinearstep.Forthenonlinearconvection-dominateddiffusionequation,thismethodcannotonlystabilizethenumericaloscillationbutalsoacceleratetheconvergenceandimprovethecomputationalefficiency.Theerroranalysisdemonstratesifthemeshsizesbetweencoarse-gridandfine-gridsatisfythecertainrelationship,thetwo-gridsolutionandthecharacteristicsfinite-elementsolutionhavethesameorderofaccuracy.Thenumericalexampleconfirmsthatthetwo-gridmethodismoreefficientthanthatofcharacteristicsfinite-elementmethod.
简介:Aself-adaptiveprecisealgorithminthetimedomainwasemployedtosolve2-Dnonlinearcoupledheatandmoisturetransferproblems.Byexpandingvariablesatadiscretizedtimeinterval,thevariationsofvariablescanbedescribedmoreprecisely,andanonlinearcoupledinitialandboundaryvalueproblemwasconvertedintoaseriesofrecurrentlinearboundaryvalueproblemswhicharesolvedbyFEtechnique.Inthecomputation,noadditionalassumptionandthenonlineariterationarerequired,andacriterionforself-adaptivecomputationisproposedtomaintainsufficientcomputingaccuracyforthechangesizesoftimesteps.Inthenumericalcomparison,thevariationsofmaterialpropertieswithtemperature,moisturecontent,andbothtemperatureandmoisturecontentaretakenintoaccount,respectively.Satisfactoryresultshavebeenobtained,indicatingthattheproposedapproachiscapableofdealingwithcomplexnonlinearproblems.