学科分类
/ 1
17 个结果
  • 简介:为特级的粒子的数字集中大小,一个冷凝作用原子核柜台(计算机数值控制)经常被使用。有一个白轻喷雾器分光计和一个被动收集者的一个新计算机数值控制模块的联合在10nm的全面尺寸范围以内做粒子数字的可能的精确解决时间的决心到40m并且在集中直到105particles/cm3。与喷雾器分光计,一颗高解决时间的粒子尺寸决心在直到105particles/cm3的一样的高数字集中的0.340m的尺寸范围也是可能的。

  • 标签: 花粉 烟灰 颗粒尺寸 测量 凝结核计算器
  • 简介:这篇论文处理磁电机水动力学(MHD)当没有滑倒状况不再是有效的时,在多孔的媒介Oldroyd8常数液体流动。修改Darcy的法律在流动建模被使用。有非线性的边界条件的非线性的微分方程与一种反复的技术在联合用有限差别计划数字地被解决。数字结果为Couette,Poiseuille和概括Couette流动被获得。效果在速度侧面上滑动参数被讨论。

  • 标签: 多孔渗水介质 磁流体动力学 滑动效果 剪切流体
  • 简介:AnanalysisispresentedwithmagnetohydrodynamicsnaturalconvectiveflowofaviscousNewtonianfluidsaturatedporousmediuminaverticalslot.TheflowintheporousmediahasbeenmodeledusingtheBrinkmanmodel.Thefully-developedtwo-dimensionalflowfromcappedtoopenendsisconsideredforwhichacontinuumofsolutionsisobtained.Theinfluenceofpertinentparametersontheflowisdelineatedandappropriateconclusionsaredrawn.Theasymptoticbehaviourandthevolumefluxareanalyzedandincorporatedgraphicallyforthethree-parameterfamilyofsolution.

  • 标签: 饱和多孔介质 磁流体 垂直 流通 牛顿流体 自然对流
  • 简介:ThispaperinvestigatestheunsteadyhydromagneticCouettefluidflowthroughaporousmediumbetweentwoinfinitehorizontalplatesinducedbythenon-torsionaloscillationsofoneoftheplatesinarotatingsystemusingboundarylayerapproximation.ThefluidisassumedtobeNewtonianandincompressible.Laplacetransformtechniqueisadoptedtoobtainaunifiedsolutionofthevelocityfields.Suchaflowmodelisofgreatinterest,notonlyforitstheoreticalsignificance,butalsoforitswideapplicatio...

  • 标签:
  • 简介:Basedonthetheoryofcomplexfunctionandtheprincipleofhomogenization,harmonicdynamicsstressofaradiallyinfiniteinhomogeneousmediumwithacircularcavityisinvestigated.Duetothesymmetry,wavevelocityisassumedtohavepower-lawvariationintheradialdirectiononly,andtheshearmodulusisconstant.TheHelmholtzequationwithavariablecoefficientisequivalentlytransformedintoastandardHelmholtzequationwithageneralconformaltransformationmethod(GCTM).Thedisplacementsandstressfieldsareproposed.Numericalresultsshowthatthewavenumberandtheinhomogeneityparameterofthemediumhavesignificanteffectsonthedynamicstressconcentrationaroundthecircularcavity.Thedynamicstressconcentrationfactor(DSCF)becomessingularwhentheinhomogeneityparameterofmediumisclosetozero.

  • 标签:
  • 简介:Nano-sizedhexagonalmagnesiumhydroxide(Mg(OH)2)withgooddispersibilitywassynthesizedbyadoubleinjection-hydrothermalmethod,utilizingpolyvinylpyrrolidone(PVP)asanadditiveandwithoptimizedprocessingparameters.SEMandBETanalysisshowedthatthemeanparticlesizeandspecificsurfaceareaoftheMg(OH)2particleswere174nmand50.77m2/g,respectively.TheFT-IRspectraandtheXRDpatternsshowedthatPVPwasadsorbedonthesurfaceoftheMg(OH)2crystal,thuseffectivelylimitingparticleagglomerationandhinderingcrystalgrowthalongthe(101)plane.TGAshowedadecreaseinthedecompositiontemperatureandanincreaseintheweightlossoftheMg(OH)2particlesduetoadditionofPVP.

  • 标签: 纳米尺寸 氢氧化镁 六边形 可控制备 MG(OH)2 聚乙烯吡咯烷酮
  • 简介:TheDonnelltheoryofshellwasappliedtodescribeshellmotion.Theinnerandoutershellswerestiffenedbytransversecomponents.Usingdeformationharmoniousconditionsoftheinterface,theeffectsofstiffenersweretreatedasreverseforcesandmomentsonthedoublecylindricalshell.Intheacousticfieldproducedbyvibrationandsoundradiationofthedoubleshell,thestructuredynamicequation,Helmholtzequationinthefluidfieldandthecontinuityconditionsofthesurfaceoffluid-structurecomposethevibrationequationcoupledbythesound-fluid-structure.Theextractofacousticpressurecomesdowntotheextractofcouplingvibrationequation.Thenearfieldacousticpressurecanbesolveddirectlybycomplicatedcalculationalmethods.

  • 标签: double CYLINDRICAL SHELL coupling VIBRATION equation
  • 简介:Alginatebeads,oftenusedforcontrolledreleaseofenzymesanddrugs,areusuallyproducedbysprayingsodiumalginateliquidintoagellingagentusingmechanicalvibrationnozzleorairjet.Inthisworkanalternativemethodofelectro-spraywasemployedtoformdropletswithdesiredsizefromahighlyviscoussodiumalginatesolutionusingconstantDCvoltage.Thedropletswerethencuredinacalciumchloridesolution.Themainobjectivewastoproducemono-sizedbeadsfromsuchahighlyviscousandnon-Newtonianliquid(1000-5000mPas).Theeffectsofnozzlediameter,flowrateandconcentrationofliquidonthesizeofthebeadswereinvestigated.Amongtheparametersstudied,voltagehadapronouncedeffectonthesizeofbeadsascomparedtoflowrate,nozzlediameterandconcentrationofalginateliquid.Thesizeofbeadswasreducedtoaminimumvaluewithincreasingthevoltageintherangeof0-10kV.Attheearlystagesofvoltageincrease(i.e.uptoabout4kV),therateofsizereductionwasrelativelylow,whilethedrippingmodedominated.However,inthemiddlepartoftherangeofappliedvoltage,wheretherateofsizereductionwashigh(i.e.about4-7kV),anunstabletransitionoccurredbetweendrippingandjetting.Attheendpartoftherange(i.e.7-10kV)jetmodeofspraywasobserved.Increasingtheheightoffallofthedropletswasfoundtoimprovethesphericityofthebeads,becauseoftheincreasedtimeofflightforthedroplets.Thiswasespeciallyidentifiableathigherconcentrationsofthealginateliquid(i.e.3w/v%).

  • 标签: Electro-spray Highly VISCOUS liquid CONSTANT DC
  • 简介:InChinamorethantwo-thirdsofavailablecoalreservesareinaridareas,where,tobeneficiatetherun-of-minecoal,thereisnotenoughwaterresourcerequiredbyconventionalprocessing.DevelopingefficientdrybeneficiationtechnologyisofgreatsignificanceforefficientcoalutilizationinChina,notablythecleancoaltechnology(CCT).Thedrycoalbeneficiationtechnologywithair-densemediumfluidizedbedutilizesair-solidsuspensionasbeneficiatingmediumwhosedensityisconsistentforbeneflciation,similarinprincipletothewetdensemediumbeneficiationusingliquid-solidsuspensionasseparatingmedium.Theheavyportioninfeedstockwhosedensityishigherthanthedensityofthefluidizedbedwillsink,whereasthelighterportionwillfloat,thusstratifyingthefeedmaterialsaccordingtotheirdensity.Inordertoobtainefficientdryseparationinair-densemediumfluidizedbed,stablefluidizationwithwelldispersedmicro-bubblesmustbeachievedtoensurelowviscosityandhighfluidity.Thepurebuoyancyofbeneficiationmaterialsplaysamainroleinfluidizedbed,andthedisplaceddistributioneffectshouldberestrained.Thedisplaceddistributioneffectsincludeviscositydisplaceddistributioneffectandmovementdisplaceddistributioneffect.Theformeriscausedbyviscosityofthefluidizedbed.Itdecreaseswithincreasingairflowvelocity.Movementdisplaceddistributioneffectwillbelargewhenairflowrateistoolowortoohigh.Ifmediumparticlesizedistributionandairflowarewellcontrolled,bothdisplaceddistributioneffectscouldbecontrolledeffectively.Abeneficiationdisplaceddistributionmodelmaybeusedtooptimizebeneficiationoffeedstockwithawideparticlesizedistributionandmultiplecomponentsinthefluidizedbed.Therheologicalcharacteristicsoffluidizedbedswerestudiedusingthefallingspheremethod.ExperimentalresultsindicatedthatthefluidizedbedbehavesasaBinghamfluid.Theplasticviscosityandyieldstresscanbe

  • 标签: 煤矿干燥选矿 空气密度流化床 中国 分离系数 稳定流化
  • 简介:Aneffectivemethodisdevelopedandusedtoinvestigatethean-tiplaneproblemofarigidlineinaconfocalellipticinhomogeneityembeddedinaninfinitemedium.Theanalyticalsolutionisobtained.Theproposedmethodisbasedupontheuseofconformalmappingandthetheoremofanalyticcontinuation.Specialsolutionswhichareverifiedbycomparisonwithexistingonesareprovided.Finally,thecharacteristicsofstresssingularityatthetipoftherigidlineinhomogeneityareanalyzedandtheextensionforcesforthecrackandtherigidlineinhomogeneityarederived.

  • 标签: RIGID LINE INHOMOGENEITY ELLIPTIC INHOMOGENEITY crack
  • 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。

  • 标签: 复合材料 亚微细粒 乳化剂 共聚合作用
  • 简介:Ananalyticalmodelisdevelopedtostudythesurfaceeffectsonthevibrationbehaviorincludingthenaturalfrequencyandthecriticalflowvelocityoffluid-conveyingnanotubesembeddedinanelasticmedium.TheeffectsofsurfaceelasticityandresidualsurfacestressareaccountedthroughthesurfaceelasticitymodelandtheYoung-Laplaceequation.AWinkler-typefoundationisemployedtomodeltheinteractionofnanotubesandthesurroundingmedium.Theresultsshowthatthesurfaceeffectshavemoreprominentinfluencesonthenaturefrequencywithsmallernanotubethickness,largeraspectratioandlargerelasticmediumconstants.Bothsurfacelayersandtheelasticmediumenhancethestabilityofnanotubes.Thisstudymightbehelpfulfordesigningthefluid-conveyingnanotubedevicesinNEMSandMEMSsystems.

  • 标签: 弹性介质 碳纳米管 表面效应 流体输送 振动分析 嵌入
  • 简介:ThesolutionsofGreen'sfunctionaresignificantforsimplificationofproblemonatwo-phasesaturatedmedium.UsingtransformationofaxisymmetriccylindricalcoordinateandSommerfeld'sintegral,superpositionoftheinfluencefieldonafreesurface,authorsobtainedthesolutionsofatwo-phasesaturatedmediumsubjectedtoaconcentratedforceonthesemi-space.

  • 标签:
  • 简介:Anumericalstudyofanon-Darcymixedconvectiveheatandmasstransferflowoveraverticalsurfaceembeddedinaporousmediumundertheefectsofdoubledispersion,melting,andthermalradiationisinvestigated.Thesetofgoverningboundarylayerequationsandtheboundaryconditionsistransformedintoasetofcouplednonlinearordinarydiferentialequationswiththerelevantboundaryconditions.ThetransformedequationsaresolvednumericallybyusingtheChebyshevpseudospectralmethod.Comparisonsofthepresentresultswiththeexistingresultsintheliteraturearemade,andgoodagreementisfound.Numericalresultsforthevelocity,temperature,concentrationprofiles,andlocalNusseltandSherwoodnumbersarediscussedforvariousvaluesofphysicalparameters.

  • 标签: 混合对流 多孔介质 分散液 表面 垂直 非线性常微分方程
  • 简介:Theinfluenceofinitialstrainstateonthedynamicresponseofanendbearingpileembeddedinisotropicsaturatedsoilisinvestigatedthroughthelinearizedtheoryofsmallelasticperturbationsuperposedonlargelystressedbodies.Thegoverningequationsforsoil,basedonBiot’sporoelasticitytheory,arederivedinthecylindricalcoordinates,andthepileismodeledbyusingtheone-dimensionalelastictheory.Theanalyticalsolutionsofpileimpedance,frequencyresponseofbothtwistangleandtimehistoryofvelocityresponseareobtainedbyusingofseparationofvariablestechnique.Finally,aparametricstudyoftheinfluenceofinitialstrainsonthetorsionalimpedance,twistangle,andvelocityresponseatthetopofthepileiscarriedout.

  • 标签: 力学 流体力学 粘性流体力学 边界层
  • 简介:Thispaperstudiesthethermal-diffusionanddiffusionthermo-effectsinthehydro-magneticunsteadyflowbyamixedconvectionboundarylayerpastanimpermeableverticalstretchingsheetinaporousmediuminthepresenceofchemicalreaction.Thevelocityofthestretchingsurface,thesurfacetemperature,andtheconcentrationareassumedtovarylinearlywiththedistancealongthesurface.Thegoverningpartialdifferentialequationsaretransformedintoself-similarunsteadyequationsusingsimilaritytransformationsandsolvednumericallybytheRunge-Kuttafourthorderschemeinassociationwiththeshootingmethodforthewholetransientdomainfromtheinitialstatetothefinalsteadystateflow.Numericalresultsforthevelocity,thetemperature,theconcentration,theskinfriction,andtheNusseltandSherwoodnumbersareshowngraphicallyforvariousflowparameters.Theresultsrevealthatthereisasmoothtransitionofflowfromunsteadystatetothefinalsteadystate.Aspecialcaseofourresultsisingoodagreementwithanearlierpublishedwork.

  • 标签: