简介:Semi-periodicstructuresnamelyinclinedwavystructures(IWS)areexperimentallyobservedincompressiblemixinglayersattwoconvectiveMachnumbers(Mc=0.11and0.47).FlowstructuresarevisualizedbythelaserinducedplanarlaserMiescattering(PLMS)technique.TwomethodsaredevelopedtoinvestigatethespatialdistributionandgeometryofIWS:(1)thedominantmodeextraction(DME)method,toextractthedominantmodesofIWSfromthestreamwisegray-levelfluctuation,and(2)thephasetracking(PT)method,toidentifytheshapeofIWS.TheresultssuggestthatpressureperturbationsaccountfortheformationofIWSintheinitialmixingregionandthejointefectofdilatationandcoherentvorticesenhancesIWSinthewelldevelopedregion.Thelargetransverse(cross-flow)scaleoftheIWSandtheirrelationtocoherentvortices(CV)indicatethatthedisturbanceoriginatedfromCVinthemixingcenterpropagatesfarintothefreestreams.TheDMEandthePTmethodareshowntobetheefectivetoolstostudythegeometricalfeaturesofwavystructuresincompressibleshearflows.
简介:Compressedthinlayersofceramicfiberinsulationareusedashightemperatureinsulatinglayersaswellasmechanicalsupportforcatalystcoatedceramicmonolithsinautomotiveemissioncontroldevices.Minimizationofenergylosses,choiceofmaterialandthicknessofcompressedinsulatinglayerarebasedonknowledgeoftheirthermalphysicalproperties.Currently,consistentmeasurementsofmaterialsinacompressedstate,astheywouldbeinemissioncontrolapplications,areabsentduetotheabsenceofsuitablemethodsforsuchtests.Atestmethodwasdevelopedformeasurementofthethermalconductivityofcompressedthinfiberlayers.Thispapersummarizestheresultsofthermalconductivityanddiffusivitymeasurementsof27compressedfiberalumina-silica-vermiculitematerialsintherangeof200-950℃.Thermalphysicalpropertiesasafunctionoftemperature,density/mechanicalpressure,thicknessandcompositionofinsulatinglayersarepresented.Thewholesetofexperimentaldataisgeneralizedon3Dsurfaceplotsanddescribedbypolynomialfunctions.Thepossibleheattransfermechanismsgoverningapparentthermalconductivityofpressedinsulationlayersarediscussed.
简介:Climatologyoftheisothermallayerdepth(ILD)andthemixedlayerdepth(MLD)hasbeenproducedfromin-situtemperature-salinityobservationsintheEastChinaSea(ECS)since1925.ThemethodsappliedontheglobalareusedtocomputetheILDandtheMLDintheECSwithatemperaturecriterionΔT=0.8℃fortheILD,andadensitycriterionwithathresholdΔσθcorrespondingtofixedΔT=0.8℃fortheMLD,respectively.WiththederivedclimatologyILDandMLD,themonthlyvariationsofthebarrierlayer(BL)andthecompensationlayer(CL)intheECSareanalyzed.TheBLmainlyexistsintheshallowwaterregionoftheECSduringApril-Junewiththicknesslargerthan15m.FromDecembertonextMarch,theareaalongtheshelfbreakfromnortheastofTaiwanIslandtothenortheastECSischaracterizedbytheCL.Twokindsofmaintemperature-salinitystructuresoftheCLinthisareaaregiven.
简介:Atheoreticalinvestigationiscarriedouttostudytheexistence,formationandbasicpropertiesofionacoustic(IA)doublelayers(DLs)inamagnetizedbi-ionplasmaconsistingofwarm/coldionsandBoltzmanndistributedelectrons.Basedonthereductiveperturbationtechnique,anextendedKortewegde-Vries(KdV)equationisderived.Thepropagationoftwopossiblemodes(fastandslow),andtheirevolutionareinvestigated.Theeffectsofobhqueness,magnitudeofthemagneticfield,ionconcentration,polarityofions,andiontemperatureontheIADLprofileareanalyzed,andthentherangesofparametersforwhichtheIADLsexistareinvestigatedindetails.
简介:Throughderivingexpressionsrelatingthedip-angle((?)_m)ofthelowerboundaryofalayertotheacousticvelocity(v_m)ofthelayerandotherpre-determinableparameters,v_mand(?)_mcanbetakenassimultaneouslyiterativevariableswhilesolvingShah‘sequations.Consequentlythepreviousmethodofcomputingv_mand(?)_mpresentedbyZHANGS.isimproved,andtheaccuracyofsolutionsincreasedgreatly.
简介:Thevelocityprofile,turbulenceintensityprofile,streakystructureandburstingfrequencyinturbulentboundarylayersoveraflatplatewithcompliantcoatingswereinvestigatedbyLaserDopplerAnemometryandcondi-tionalsamplingtechniques.Thisexperimentledtotheconclusionsthatinboundarylayerflowsonacompliantwall,ascomparedwiththatonarigidwall,theloglawregionwasextendedfurtherawayfromthewall,andthatthemaximumvalueofeachturbulenceintensityprofileinthenearwallregionwasreducedandtheburstingfrequencyobviouslydecreasedwiththecompliantcoatings.Onepointworthyofnoticewasthattheaboveresultswereverymuchlikethoseofpolymerdragreductionexperiments.
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简介:这份报纸被建议理解卟啉层的相互作用,两价的分子由使用abinitio和密度在他们的内部区域交往功能的理论(DFT)方法。我们不使用了,公司,和O2与卟啉层交往的两价的分子。有有N4核心的tetra-pyrrlic戒指的最普通的集中Fe的metalloporphyrin结构为学习被选择。卟啉卟啉的优化(P我-PII)和卟啉两价的分子--卟啉(P我-AB-PII)(AB=没有,公司,和O2)建筑群用HF被执行方法。为了理解planarity并且拨出叠,卟啉并且也缩放推断在卟啉层之间的两价的分子的分离P我-AB-PII建筑群(在哪儿AB=没有,公司,并且O2)用结构的性质和分子的静电的潜力(MEP)被分析。MEP用与6-31+G*基础一起的DFT的功能的B3PW91为P我-PII和P我-AB-P从HF获得的II建筑群方法。
简介:Thestabilitycharacteristicsoflaminarboundarylayersovercompliantwallswasstudiedbythelineartheory.Unlikethepreviousauthors,thecoupledmotionofthefluidandsolidwasrequiredtosat-isfythecontinuityconditionsofboththevelocityandstressattheinterface.Resultsofcalculationsshowthatasthespeedratioordensityratioexceedsacertainthresholdvalue,thetwotypesofunstablewaveswillnolongerbedistinguishable,andthetangentialcomponentofthedisturbancestressisnolongernegligi-ble.Sotheneglectofit,asthepreviousauthorsdid,isunjustified.
简介:ThispaperpresentsanewfamilyofsolutionstothesingularlyperturbedAllen-Cahnequationα~2Δu+u(1-u~2)=0inasmoothboundeddomainΩR~3,withNeumannboundaryconditionandα>0asmallparameter.Thesesolutionshavethepropertythatasα→0,theirlevelsetscollapseontoaboundedportionofacompleteembeddedminimalsurfacewithfinitetotalcurvatureintersecting?Ωorthogonallyandthatisnon-degeneraterespectto?Ω.Theauthorsprovideexplicitexamplesofsurfacestowhichtheresultapplies.
简介:Atechniqueispresentedforcreatingsurface-adheringdustlayersunderdefinedconditions,andcharacterizingandstressingthelayerscreated.Theproceduredescribedisshowntobesuitableforthequantitativeevaluationoftheeffectsofdifferentparameterssuchasparticlesize,porosityandsurfaceroughnessetc.onthestabilityofparticlelayers.
简介:Thispapergivesanintroductionintothedissipationintegralmethod.Thegeneralintegralequationsforthethree-dimensionalcasearederved.Itisfoundthatforapracticalcalculationalgorithmtheintegralmonentumequationandtheintegralenergyequationaremsotuseful.UsingTwodifferentsetsofmeanvelocityprofilesthehyperbolicalcharacterofadissipationintegralmethodisshown.Testcasesfortwo-andthree-dimensionalboundarylayersareanalysedanddiscussed.Thepaperconcludeswithadiscussionoftheadvantagesandlimitsofdissipationintegralmethods.
简介:TheeffectsofgrowthtimeonthestructureandmorphologyofcubicGaNnucleationlayersonGaAs(001)substratesbymetalorganicchemicalvapordeposition(MOCVD)havebeeninvestigatedusingasynchrotronX-raydiffraction(XRD).TheXRDresultsshowthattheGaN111reflectionsat54.75°inχareameasurablecomponent,howeverthe002reflectionsparalleltoGaAs(001)surfacearenotdetected.TheXRDΦscansandpolefiguresgiveaconvincingproofthattheGaNnucleationlatyersshowexactlythecubicsymmetricalstructure.Thecoherencelengthsalongtheclose-packed<111>directionestuimatedfromthe111peakarenanometerorderofmagnitude,Theoptimalphotoluminescence(PL)spectrumwasobtainedfromthecubicGaNepilayerdepositedonthenucleationlayerfor60sec.
简介:Inthispaper,usingLin'sintegralidentitytechnique,weprovetheoptimaluniformconvergenceθ(N_x~(-2)In~2N_x+N_y~(-2)In~2N_y)intheL~2-normforsingularlyper-turbedproblemswithparaboliclayers.Theerrorestimateisachievedbybilinearfi-niteelementsonaShishkintypemesh.HereN_xandN_yarethenumberofelementsinthex-andy-directions,respectively.Numericalresultsareprovidedsupportingourtheoreticalanalysis.
简介:作者调查Prandtl边界层理论能严厉地为被验证的边界层的一些例子。所有为与各种各样的Dirichlet边界条件(指定速度)装备的牛顿的液体与不可压缩的海军司烧方程他们被联系。这些例子包括一个家庭(非线性的3D)飞机平行流动,一个家庭(非线性)有在边界的一致注射和吸的平行管子流动,以及流动。我们也在建立Prandtl类型理论的有效性识别关键成分,即,一光谱海军司烧系统的近似答案上的限制由联合Prandtl类型系统的inviscid答案和解决方案构造了。这是除与Prandtl类型系统的well-posedness有关的著名问题以外的一个另外的困难。看起来主要阻塞到确认光谱限制状况是边界层的可能的分离。这些例子的一个普通主题也经由在边界压制速度正常到边界或由注射和吸以便是边界层的分离的抑制光谱限制能被验证。一条元定理然后被介绍它盖住这里考虑的所有盒子。
简介:Thespatialevolutionof2-Ddisturbancesinsupersonicsharpconeboundarylayerswasinvestigatedbydirectnumericalsimulation(DNS)inhighordercompactdifferencescheme.Theresultssuggestedthat,althoughthenormalvelocityinthesharpconeboundarylayerwasnotsmall,theevolutionofamplitudeandphaseforsmallamplitudedisturbanceswouldbewellinaccordancewiththeresultsobtainedbythelinearstabilitytheory(LST)whichsupposestheflowwasparallel.Theevolutionofsomefiniteamplitudedisturbanceswasalsoinvestigated,andthecharacteristicoftheevolutionwasshown.Shockletswerealsofoundwhentheamplitudeofdisturbancesincreasedoversomevalue.