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321 个结果
  • 简介:Inthepresentpaperitwillbeshownthat,bytakingthereferenceframemovingwiththevelocityoffluidattheinterlaceoftwosteadyparallelstreams,thelaminarboundarylayerflowinthetwofluidscanbedecoupledintotwoflows.Theseareexactlythesameasthelaminarboundarylayerflowsalongaflatplate.Andthat,byusingtheexistingexactsolutionofthelaminarboundarylayerequationfortheboundarylayerflowalongaflatplateandappropriateboundaryconditions.Anexactsolutionofthelaminarboundarylayerequationforthelaminarboundarylayerbetweentwoparallelstreamswithdifferentdensities,viscocitiesandvelocitiesisgivenelegantly.ForthecasesconsideredbyLock,theresultsobtainedbythepresentmethodarecomparedwithLock’snumericalcalculationsindetail.

  • 标签: BOUNDARY kyer PARALLEL STREAMS Blasius SOLUTION
  • 简介:Asimplelayer-by-layerdepositiontechniquewasusedtofabricatethemultilayerthinfilmsofunmodifiedsilvertriangularnanoplates(AgTNPs).ThemultilayerofAgTNPsthinfilmswerefabricatedbyalternatedepositionofeachanionicsodiumcitratestabilizedAgTNPsandcationicpoly(diallyldimethylammoniumchloride).AllpreparedAgTNPsmultilayerthinfilmswereexhibitedastrongplasmonbandatthewavelengthof667nm,whichconfirmedtheformationofAgTNPsontothesubstrate.Thecharacteristicsofthemultilayerthinfilmswereinvestigatedusingcontactanglemeasurement,UV-visiblespectroscopy,X-raydiffractionanalysis(XRD),atomicforcemicroscope(AFM)andfieldemissionscanningelectronmicroscope(FESEM).Asthesefilmsaretobeusedasamercury(II)colorimetricsensor,thechangesinopticalpropertiesofthefilmswereevaluatedforvariousmercury(Ⅱ)concentrations.AgTNPsassembledintothinfilmsshowedastrongcolorshiftfrombluetomauveandcolorlesswhenexposedtomercury(Ⅱ).Theconstructedmultilayerthinfilmsexhibitedexcellentcolorchangesofmercury(II)withalinearrangebetween0.5and20ppm.Thelimitofdetection(LOD)andlimitofquantitation(LOQ)were0.45±0.002and1.52±0.002ppm,respectively.TherecoveryvaluesofAgTNPsmultilayerthinfilmsaresatisfactoryintherangeof100.1%-106.4%whenappliedtodeterminingmercury(Ⅱ)inwatersamples.

  • 标签:
  • 简介:Biocompatible聚合电解质multilayers(PEM)和polysiloxane混血儿涂层被准备改进可被细菌破坏的Mg合金AZ31的腐蚀抵抗。PEM,包含了poly轮流出现,并且poly(allylaminehydrochloride)(哼),是第一在经由静电的相互作用的AZ31合金底层的表面上自我装配,是指明了(PAH/PSS)5/AZ31。然后,(PAH/PSS)5/AZ31样品被蘸进制作PMTMS的答案拍摄的methyltrimethoxysilane(MTMS),指定了为PMTMS/(PAH/PSS)5/AZ31。表面形态学,微观结构和这些电影的化学作文被FE-SEM,FTIR,XRD和XPS调查。Potentiodynamic极化,电气化学的阻抗光谱学和氢进化大小证明合成电影显著地提高了的PMTMS/(PAH/PSS)5/AZ31在丝等的AZ31合金的腐蚀抵抗平衡盐答案(HBSS)。PAH和PSS电影有效地包括Ca3(PO4)2和hydroxyapatite改进了帽子混合物的免职(哈)。而且,合成涂层的腐蚀机制被讨论。这些涂层能是为可被细菌破坏的Mg合金的其他的候选人涂层。

  • 标签: AZ31镁合金 可生物降解 复合涂层 耐腐蚀性 聚合物 甲基三甲氧基硅烷
  • 简介:Theeffectofthefacethicknesstocoreheightratioondifferentmulti-layerpyramidalcoresandwichcolumnsunderin-planecompressionisinvestigatedtheoreticallyandnumerically.Numericalsimulationisingoodagreementwiththeory.Resultsindicatethatonespecifiedfacethicknesstocoreheightratiocorrespondstooneoptimumlayernumberofmulti-layerpyramidalcoresandwichcolumnsinconsiderationofengineeringapplication.Thisresultcanguidethesandwichstructuredesign.

  • 标签: 夹层结构 最佳层数 内压缩 面层厚度 数值模拟 结构设计
  • 简介:分别地,搬运器官的轻射出的设备(OLED)的层(HTL)的洞被真空免职和旋转涂层方法处理在哪儿N,N鈥?biphenyl-N,N鈥?二度(3-methylphenyl)-1,1鈥?biphenyl-4,4鈥?diamine(TPD)并且(vinylcarbazole)(PVK)poly充当了洞运输材料。Tris-(8-hydroxyquinoline)铝(Alq3)作为搬运层的轻射出的层和电子被利用。设备房间的基本结构是:indium-tin-oxide(ITO)/PVK:TPD/Alq3/Mg:Ag。设备的electroluminescent(EL)特征被描绘。结果证明EL系列的山峰在530nm被定位,它遵循了Alq3的描绘的光谱。与使用真空免职方法相比,有直到26135cd/m2的最大的发光性的绿排放能被用纺纱涂层技术选择合适的溶剂在15V的开车电压完成,并且它的最大的发光性效率是在5.5V的开车电压的2.56lm/W。CLC数字TN383+.1这个工程被部水平资助和UESTC的年轻优越工程赞助(资助号码:UESTC-2006206)

  • 标签: 空穴转运层 有机发光装置 真空沉积 自旋
  • 简介:轧了射出二极管(LEDs),薄AlInN层在堵住层(EBL)的电子前面插入了的基于的蓝光试验性地被学习。插入薄EBL能改进轻产量力量并且减少效率,这被发现与常规AlGaN对应物相比低垂。基于数字模拟和分析,当薄AlInN层被使用时,电、光的特征上的改进主要被归因于电子漏电流的减小,它在量井(QW)增加搬运人的集中。

  • 标签: 蓝光发光二极管 GAN 阻挡层 电子 实验 N层
  • 简介:Inthispaper,takingitsturbulentexchangecoefficientasafunctionoftheLagrangiantimescaleandstandardvarianceoftheturbulenceinatmosphere,theatmosphericdispersionPDFmodelsareobtainedonthebasisofatmosphericdiffusionK-theory.Inthemodelthestatisticsofwindspeedaredirectlyusedasitsparametersinsteadofclassicdispersionparameters.Thebi-GaussianPDFisderivedinconvectiveboundarylayer(CBL),fromthestatisticsofverticalvelocityinbothofthedowndraftandupdraftregionsthatareinvestigatedtheoreticallyintheotherpartofthispaper.GivingthedrivenparametersoftheCBL(includingtheconvectivevelocityscalew*andthemixingdepthh_i)andthetime-averagedwindspeedatreleaselevel,thePDFmodelisabletosimulatethedistributionofconcentrationreleasedatanylevelsintheCBL.ThePDF’ssimulationsarefairlyconsistentwiththemeasurementsinCONDORSexperimentortheresultsbroughtoutbysomenumericalsimulations.

  • 标签: ATMOSPHERIC DIFFUSION PROBABILITY distribution function (PDF)
  • 简介:Effectsofdepositionlayerpositionandnumber/densityonlocalbendingofathinfilmaresystematicallyinvestigated.Becausethedepositionlayerinteractswiththethinfilmattheinterfaceandthereisanoffsetbetweenthethinfilmneutralsurfaceandtheinterface,thedepositionlayergeneratesnotonlyaxialstressbutalsobendingmoment.Thebendingmomentinducesaninstantout-of-planedeflectionofthethinfilm,whichmayormaynotcausethesocalledlocalbending.Thedepositionlayerismodeledasalocalstressor,whoselocationanddensityaredemonstratedtobevitaltotheoccurrenceoflocalbending.Thethinfilmrestsonaviscouslayer,whichisgovernedbytheNavier-Stokesequationandbehaveslikeanelasticfoundationtoexerttransverseforcesonthethinfilm.Theunknownfeatureoftheaxialconstraintforcemakesthegoverningequationhighlynonlinearevenforthesmalldeflectioncase.Theconstraintforceandfilmtransversedeflectionaresolvediterativelythroughthegoverningequationandthedisplacementconstraintequationofimmovableedges.Thisresearchshowsthatinsomespecialcases,thedepositiondensityincreasedoesnotnecessarilyreducethelocalbending.Bycomparingthethinfilmdeflectionsofdifferentdepositionnumbersandpositions,wealsopresenttheguidelineofstrengtheningorsuppressingthelocalbending.

  • 标签: 薄膜表面 局部弯曲 粘性 轴向压力 挠度方程 交互界面
  • 简介:SomepeoplearesuspiciousoforalEnglishlearningfortheyhavebeenaccustomedtotheoldtraditionalclassroomtraining.Thispaperdiscussessomenewteachingtechniquesinoralclass,whichbreaksthetraditionalteachingmethods.Ifteachersareawareoftheadvantagesofthesenewmethodsandputthemintopractice,thenwecancreatealivelyandnaturalatmospheresothatthestudentswilllosetheirinhibitionandlearnEnglishhappily.Themainpointofthispaperisthatthebestteachingmethodcanproducethebesteffectanditshouldbeacombinationofsomeflexibleandvariousapproachesratherthanonlyonesingleteachingmethodaswellasthecooperationofteacherandstudents.

  • 标签: 英语教学 口语教学 教学方法 教师素质
  • 简介:Wepresentanumericalstudyonthepatternformationinatwo-dimensionalvibratedgranularlayerbyamoleculardynamicsalgorithm.Throughanalysingthegranulardensitydistribution,wecanexploretheinnermovementprocessofparticles.Itisconfirmedthatthereareadispersiveregimeandasaturationregimeforfrequencydependence,betweenwhichacriticalfrequencyexists,Itisfoundthatthereisanothersaturationregimeforthicknessdependence,Thewavelengthincreaseswithincreasinglayerthickness,butthereisacriticalthicknessafterwhichthewavelengthisunchanged.

  • 标签: 晶粒薄膜 波长选择 数字模拟
  • 简介:UsingtheinterpolationtheoryofafamilyoflinearoperatorsandtheSobolevspaces,weintroduceaquantityJ_∈~4(λ)whichdepictstheshapeoftheboundarylayer,andthenanalyzetheboundarysingulartyofJ_∈~4(λ).Ourresultshowsthatthethicknessoftheboundarylayer(ortheregularregionofJ_∈~4(λ))isintrinsicallyrelatedtothereciprocaloftheorderoftheequation;thelossofboundaryconditionsbetweenthesingularsolutionandthelimitsolutiondoesnotinfluencethethicknessoftheboundarylayer,butitinfluencestheprocessofincreasingsingularityofJ_∈~4(λ);themorethelossofboundaryconditions,thesmallertheregionofincreasingsingularity.Finally,wegiveadefinitionofaneighborhoodofsuddenchangeandproposeanopenproblemregardingthisneighborhood.

  • 标签: The INTERPOLATION theory the interior ESTIMATE
  • 简介:ADopplersodarsystemcontrolledbymicrocomputerisdescribedinthispaper.Thesodarwasusedtodetecttheverticaldistributionofwindandtemperaturestratificationintheatmosphericboundarylayer.Thedetectingresultsshowthatatnighttheverticaldistributionofwindisverycomplicated,whichcanappearasastructureoftwoorthreelayers.Innocturnalatmosphericboundarylayersometimesthereexistsverythinlayerinmulti-layerinversionanditcanberetainedforalongtime.

  • 标签: DOPPLER SODAR ATMOSPHERIC boundary layer WIND
  • 简介:Aprogramincorporatingtheparallelcodeoflargeeddysimulation(LES)andparticletransportationmodelisdevelopedtosimulatethemotionofparticlesinanatmosphericturbulentboundarylayer(ATBL).Amodelofparticlesof100-micrometerordercouplingwithlargescaleATBLisproposed.Twotypicalcasesarestudied,onefocusesontheevolutionofparticleprofileintheATBLandthelandingdisplacementofparticles,whereastheotheronthemotionofparticlestream.

  • 标签: 粒子传输 大气 边界层紊乱 旋涡模拟
  • 简介:Anovelfabricationprocessformicropatternswithcurvaturewasintroduced.Thecurvedstructuresweremadebycompensatingrectangularmicrostructureswithliquidphotoresistlayer.Becauseofthesurfacetensionoftheliquidinmicroscale,variousshapesofmeniscuscanbemadeonthemicrochannels.Themicrochannelsweremadeonthesiliconsubstrateinadvance,andthentheliquidlayerwascoatedonthemicrochannels.Fromthenatureofliquidbehavior,thecurvedpatternswithsmoothsurfaceareobtained,whichcannotbemadeeasilywiththeconventionalmechanicalmachining,aswellaswiththemicrofabricationprocesses,suchaswetanddryetching.Withthisprinciple,itisexpectedthatthesmoothandcurvedsurfacescanbemadebysimpleprocessesandtheresultscanbeappliedwidely,suchasopticalpatterns.

  • 标签: 液态光致抗蚀剂 微结构 制备 弧形 微细加工工艺 表面光滑
  • 简介:AnewLDMOSTstructure,namedB-LDMOSTthathasaburiedlayerunderthedrainisproposed.Theburiedlayerisnotconnectedtothedriftregion,soitcanoptimizetheverticalfielddistributionandincreasebreakdownvoltage.TheanalysisandthesimulatedresultsshowthatB-LDMOSTcanincreasebreakdownvoltage,withalmostnegligibleinfluenceontheotherparameterssuchason-resistance,switchingtime,andsoon.

  • 标签: 埋层 击穿电压 接通电阻 转换时间 高压集成电路 B-LDMOST
  • 简介:Thefar-fieldnoiseradiatedfrommixinglayersisdeterminedbythenear-fieldflowdynamicswhichissensitivetotheinitialperturbationofinstabilityintroducedphysicallyornumerically.Thisstudyfocusesontheeffectsofthephasedelayintwoinitialperturbations,oneatthefundamentalwavenumberandtheotheratitssubharmonicbothcalculatedfromlinearinstabilityanalysis,onthesoundgenerationinmixinglayers.Whendifferentphasedelaysφ_1changingfromzeroto2πisappliedonthefundamentalmode,weobservedifferentvortexmergingprocesses(e.g.vortexpairingortearing).Thestrongnonlinearinteractioninthemergingprocessgeneratesmostofthenoisefrommixinglayers.Thereshowsapatterninaperiodof2πfortheresponseoffar-fieldsoundtothechangeofφ_1.Similareffectsonthedynamicsandacousticscanbeachievedbyaddingdifferentphasedelaysφ_2tothesubharmonicmodeinstead,however,theresponserepeatsinaperiodofonlyπforφ_2.Theeffectsofthecombinationofdifferentphasedelaystootherparameters,includingtheamplitudeandwavenumberforeachperturbations,arealsoinvestigated.Alltheresultsindicateacriticalroleofnonlinearityinthesoundgenerationmechanismofmixinglayers.

  • 标签: 初始扰动 混合层 噪音 非线性相互作用 线性稳定性分析 血流动力学
  • 简介:TheevolutionofG?rtlervorticesanditsinteractionwithotherinstabilitiesareinvestigatedinthispaper.BoththeMackmodeandtheG?rtlermodeexistinhypersonicboundary-layerflowsoverconcavesurfaces,andtheirinteractionsarecruciallyimportantinboundarylayertransition.WecarryoutadirectnumericalsimulationtoexploretheinteractionbetweentheG?rtlerandtheobliqueMackmode.TheresultsindicatethattheinteractionbetweentheforcedG?rtlermodeandtheobliqueMackmodepromotestheonsetofthetransition.TheforcedobliqueMackmodeissusceptibletononlinearinteraction.BecauseofthedevelopmentoftheG?rtlermode,theforcedMackmodeandotherharmonicmodesareexcited.

  • 标签: 边界层转捩 高超声速 非线性相互作用 失稳 直接数值模拟 边界层流动
  • 简介:ThebiomassesoffishesatthebottomlayeroftheBohaiSeaareextimatedbyanalysingthedataonsamples(447hauls,morethan0.2millioninnumberor20tinweightoffishes)collectedmonthlybyourinstitutefromApril,1982toMay,1983byapairofbottomtrawlsthroughtheBohaiSea.Theexploitationproblemsarealsodiscussedinthispaper.

  • 标签: Bohai EXPLOITATION biomass institute SEASONAL FIFTH