简介：Numerousexperimentalevidencesshowthatthegrainsizemaysignificantlyaltertheyieldstrengthofmetals.Similarly,in-strengthenednickel-basedsuperalloys,theprecipitatesizealsoinfluencestheiryieldstrength.Then,howtodescribesuchtwokindsofsizeeffectsontheyieldstrengthisaverypracticalchallenge.Inthisstudy,accordingtoexperimentalobservations,acollinearmicro-shear-bandsmodelisproposedtoexplorethesesizeeffectsonmetalmaterials’yieldstrength.Ananalyticalsolutionforthesimplemodelisderived.Itrevealsthattheyieldstrengthisafunctionofaveragegrain-sizeorprecipitate-size,whichisabletoreasonablyexplainsizeeffectsonyieldstrength.Thetypicalexamplevalidationshowsthatthenewrelationshipisnotonlyabletopreciselydescribethegrain-sizeeffectinsomecases,butalsoabletotheoreticallyaddresstheunexplainedHall-Petchrelationshipbetweentheγprecipitatesizeandtheyieldstrengthofnickel-basedsuperalloys.

简介：Thispapercontributestoextractinginformationfromsignalsofbroadbandultrasonicattenuationspectrumforeffectiveutilizationinparticlesizecharacterization.Thesingleparticlescatteringmodelandthecoupled-phasemodelareformulatedsimultaneously,therelationshipbetweenparticlesizedistributionandultrasonicspectrumisestablished,andaconvergencecriterionforcalculationisquantified.Demonstrationinversionbytheoptimumregularizationfactormethodiscarriedouttoyieldtypicalnumericalresultsfordiscussion.Withtheexperimentalset-updevelopedbytheInstituteofParticleandTwo-PhaseFlowMeasurement(IPTFM)attheUniversityofShanghaiforScienceandTechnology,sandsedimentparticlesizeismeasuredbyattenuationspectrumandanalyzedusingtheaboveinversionalgorithmandtheoreticalmodels.Tovalidatetheproposedultrasonicspectrumparticlesizingmethod,resultsarecomparedwiththoseobtainedbymicroscopy.

简介：Inphasefieldfracturemodelsthevalueoftheorderparameterdistinguishesbetweenbrokenandundamagedmaterial.Atcrackfacestheorderparameterinterpolatessmoothlybetweenthesetwostatesofthematerial,whichcanberegardedasphases.Thecrackevolutionfollowsimplicitlyfromthetimeintegrationofanevolutionequationoftheorderparameter,whichiscoupledtothemechanicalfieldequations.Amongotherphenomenaphasefieldfracturemodelsareabletoreproducecracknucleationininitiallysoundmaterials.Fora1Dsettingithasbeenshownthatcracknucleationistriggeredbythelossofstabilityoftheunfractured,spatiallyhomogeneoussolution,andthatthestabilitypointdependsonthesizeoftheconsideredstructure.Thisworknumericallyinvestigatestowhichextendsizeeffectsarereproducedbythe2Dphasefieldmodel.Exemplarily,afiniteelementstudyoftheholesizeeffectisperformedandthesimulationresultsarecomparedtoexperimentaldata.

简介：Inthiswork,sandwichbeamsarestudiedtorevealtheunderlyingsizeeffectsoftheperiodiccorecellsforthefirsttimewithintheframeworkoffreevibrationanalysisofsuchanadvancedlightweightstructure.Theenergyequivalencemethodisformulatedasatheoreticalapproachthattakesintoaccountthecellsizeeffect.Itiscomparedwiththeasymptotichomogenizationmethodanddirectfiniteelementmethodsystematicallytoshowtheirconsistenceandapplicability.Theaccuracyoffreevibrationresponsespredictedbythedetailedfiniteelementmodelisusedasthestandardofcomparison.Itisshownthatthecellsizeisanimportantparametercharacterizingthecellularcorerigiditiesthatinfluencevibrationresponses.Thehomogenizationmodelagreesexactlywiththeasymptoticsolutionoftheanalyticalexpressionofthebeammodelonlywheneverthecellsizetendstobeinfinitelysmall.

简介：Informationofdropletsizeandsizedistributionlaysthebasisforinvestigationsofatomizationmechanismsandperformanceoptimization.However,thelaserdiffractionandphaseDopplerparticleanalyzershavedifficultyinaccuratelycharacterizingsprayswithawiderangeofdropletsizesandverylargedroplets,especiallyifalargenumberofdropletsareaspherical.Amethodtomeasuresizeinsuchlargedropletspraysbasedondigitalimagingwithbackwardilluminationwasdeveloped,includinganimageacquisitionsystemandimageprocessprograms.Calibrationofthemeasurementsystemwasperformedusingadotcalibrationtargetwithdifferentdotsizes.Anexperimentalsetupwasdesignedandestablishedtocharacterizespraynozzlesunderdifferentoperationloads,aswellasdifferentnozzlearrangements.Resultsshowthatthedropletsizeofspraysrangesfromdozensofmicronstoseveralmillimeters.Thesuperiorityofwideloadrangeforsuchnozzleswasindicatedbythesize-measurementresultsunderhalf-loadtofull-loadoperations.Thepresentstudyrevealedthattheimageprocessingtechniquecanbeeffectivelyimplementedforin-linesizemeasurementsofsprayswithawidedistributionofdropletsizeandasphericaldroplets,whichwouldbedifficulttocharacterizebyothermethods.

简介：包括清除的干燥免职和装紧和成核，由干燥、湿的过程的尺寸依赖者喷雾器移动上的当前的知识的地位被考察。在清除的干燥免职andbelow云上的理论评价和测量数据之间的Thelargest差异为亚微米粒子。早干燥的免职模型，基于房间和风隧道大小发展了，趋于与最近的领域大小相比由约一个数量级为亚微米粒子低估干燥免职速度(V_d)。最近发达的模型能为亚微米粒子预言合理V_d值，但是转移到更大的粒子的预言的最小的V_d缩放的不现实的联盟者。实质地也由掉落的液体落下喷雾器粒子清除的装紧的理论研究为亚微米粒子低估清除系数。基于领域，大小能作为理论清除模型的一种选择服务的实验公式。清除的解决ofsize的装紧建模的未来开发需要包括更多的降水性质(例如，微滴表面区域)并且被详细的云评估微物理模型和可得到的大小。为空隙的喷雾器的in-cloudremoval的几个最近发达的成核清除parameterizations当与包裹模型作比较时，给可比较的结果；然而，一旦合适的地大小是可得到的，他们需要被验证。理论的更多和领域研究也被需要以便更好在清除的成核理解器官的喷雾器的角色过程。

简介：ParticlebasedmodelsofcompositeanodesareusefultoolsforexploringthebehaviorofSOFCsystems.Aspartofoureffortstodevelopmodelsforunderstandingfuelcells,wehavebeenbuildingmodelsofNi-YSZcompositeanodesusingexperimentallymeasuredparticlesizedistributions.Theobjectivesofthisstudyweretocharacterizethepercolationthresholdandconductivityofthesemodelsincomparisontosimplermonodispersedandbiphasicparticlesizedistributionsfromtheliterature.Wefoundthattheaveragevaluesfortheonsetofpercolationandthemeasuredconductivityofthemodelswithexperimentallymeasuredparticlesizedistributionsaresimilartothoseforthesimpledistributionsandtheexperimentallymeasureddistributions.Foralloftheconfigurationsevaluated,theonsetofpercolationintheNickelphaseoccurredatasolidfractionofNickelbetween20%and25%.ThiscorrespondedalmostexactlytothepointatwhichthecoordinationnumberbetweenNickelphaseparticlesreached2.2.Thesignificantfindingwasthatthevariationinthevaluefortheconductivity,asmeasuredbythestandarddeviationoftheresults,wasseveralordersofmagnitudehigherthanforthesimplersystems.Weexploredthevalidityofourassumptions,specificallytheassumptionofrandomparticleplacement,bybuildingaparticlemodeldirectlyfromFIB-SEMdata.Inthisreconstruction,itwasclearthatthelocationofparticleswasnotrandom.Particlesofthesametypeandsizehadmuchlikelihoodofcontacthigherthanwouldindicatedbyrandomlocation.

简介：Thecombinedeffectsofvoidsizeandvoidshapeonthevoidgrowtharestudiedbyusingtheclassicalspectrummethod.AninfinitesolidcontaininganisolatedprolatespheroidalvoidisconsideredtodepictthevoidshapeeffectandtheFleck-Hutchinsonphenomenologicalstraingradientplasticitytheoryisemployedtocapturethesizeeffects.Itisfoundthatthecombinedeffectsofvoidsizeandvoidshapearemainlycontrolledbytheremotestresstriaxiality.Basedonthis,anewsize-dependentvoidgrowthmodelsimilartotheRice-Traceymodelisproposedandanimportantconclusionaboutthesize-dependentvoidgrowthisdrawn:thegrowthrateofthevoidwithradiussmallerthanacriticalradiusrcmaybeignored.Itisinterestingthatrcisamaterialconstantindependentoftheinitialvoidshapeandtheremotestresstriaxiality.

简介：Piezoelectricsuperlatticeisapotentialcomponentfornanoelectromechanicalsystems.Duetothestrongnonlocaleffectsuchasflexoelectriceffectatinterfaces,classicalpiezoelectrictheoryisunabletoaccuratelydescribetheelectromechanicalresponseofpiezoelectricsuperlatticeatnanoscalescale.BasedonthepreviousnonlocalthermodynamicstheorywithflexoelectriceffectLiuetal.(2016),thesizedependentelectromechanicalpropertiesofpiezoelectricsuperlatticesmadeofBaTiO_3(BTO)andPbTiO_3(PTO)layersareinvestigatedsystematicallyinthepresentwork.GiantstraingradientisfoundneartheinterfacebetweenBTOandPTOlayers,whichleadstothesignificantenhancementofpolarizationinthesuperlatticeduetotheflexoelectriceffect.ForthepiezoelectricBTO–PTOsuperlatticeswithdifferentunitcellsizes,thethicknessofinterfacewithnontrivialstraingradientisalmostconstant.Theinfluenceofstraingradientattheinterfacebecomessignificantwhenthesizeofsuperlatticedecreases.Asaresult,astrongsizedependenceofelectromechanicalpropertiesispredictedforthepiezoelectricBTO–PTOsuperlattices.Inparticular,forthesuperlatticeswithaspecificthicknessratioofBTOandPTOlayers,thepiezoelectricresponsecanbeseveraltimeslargerthanthatofbulkstructure.Thepresentworkdemonstratesapracticalwaytodesignthepiezoelectricsuperlatticeswithhighpiezoelectriccoefficientbyusingthenonlocaleffectatnanoscale.

简介：ZnOnanoparticleswithverynarrowsizedistributionweresynthesizedbycouplinghomogeneousprecipitationwithmicroemulsionunderpulsedmicrowaveheating.TheconditionsofpreparingZnOnanoparticleswereinvestigated.TheproductswerecharacterizedwithDTA,TGA,XRD,TEMandUV-Vis.ThesynthesizedZnOnanoparticeshadmuchstrongerultravioletabsorptivitythannormalZnOpowders;theaveragesizeofproductswassensitivetothevariationofthepowerordurationofmicrowaveirradiation.

简介：Thispaperattemptstoinvestigatethebucklingandpost-bucklingbehaviorsofpiezoelectricnanoplatebasedonthenonlocalMindlinplatemodelandvonKarmangeometricnonlinearity.Anexternalelectricvoltageandauniformtemperatureriseareappliedonthepiezoelectricnanoplate.Boththeuniaxialandbiaxialmechanicalcompressionforceswillbeconsideredinthebucklingandpost-bucklinganalysis.Bysubstitutingtheenergyfunctionsintotheequationoftheminimumtotalpotentialenergyprinciple,thegoverningequationsarederiveddirectly,andthendiscretizedthroughthedifferentialquadrature(DQ)method.Thebucklingandpost-bucklingresponsesofpiezoelectricnanoplatesarecalculatedbyemployingadirectiterativemethodunderdifferentboundaryconditions.Thenumericalresultsarepresentedtoshowtheinfluencesofdifferentfactorsincludingthenonlocalparameter,electricvoltage,andtemperatureriseonthebucklingandpost-bucklingresponses.

简介：产生交通的逃亡者灰尘是在北京的城市的大气的微粒污染的来源。这篇论文介绍暂停方法，在AP-42文件由USEPA推荐了，为收集北京道路表面灰尘。分析为道路表面灰尘的集体尺寸分发在数字尺寸分发和一个双山峰模式显示出单个山峰的分布。一条高级道路上的道路灰尘的集体集中分发的中部的直径在一条低档道路上比那高。到PM10的PM2.5的比率与那为香港在类似的研究获得了一致。为二件选择道路样品，尺寸分发的平均相对偏差是10.9%和11.9%。所有结果显示有效地在这个论文罐头介绍的方法从交通决定逃亡者灰尘的尺寸分发。

简介：

简介：ControllingthesizeoffragraneemicrocapsulesusingdesignedagitatorpaddleswasinvestigatedandstudiedbyCFDsimulation.First,differentfluidflowswereestablishedbyvaryingstirringspeeds,reactorscales,andagitatorpaddledesign,andtheeffectsofeachonparticlesizeanddistributionofpreparedmicrocapsulesweredetermined.Theexperimentalresultsshowedthatthepatterndesignoforificesintheplatepaddlescontroltheflowfieldwell.Narrowparticle-sizedistributionsofthemicrocapsuleswereobtained.Thefluidflowcharacteristicsincludingfluidvelocityfield,turbulentkineticenergyfield,andshearstressdistributionforthedifferentagitatorpaddletypesindifferentreactionkettlesweresimulatedusingCFDtechnology.Thecorrelationsbetweensimulateddataandexperimentalresultswereanalyzed.Significantly,thesimulatedaverageflowvelocitywasfoundtoshowgoodnegativelinearcorrelationw让htheaverageparticlesizeofpreparedmicrocapsules,withacorrelationofy=-2.166x+42.626.

简介：Thereisaneedtostandardizemethodsassociatedwiththedispersionofnanomaterialsinnano（eco）toxicologicalinvestigations.Thefirststeptowardthisgoalistounderstandthedegreeofvariabilitythatexistsinnanomaterialdispersionspreparedbyusingdifferentprotocols.Usingtwocasestudies,thedegreeofvariabilityinTiO2nanomaterialdispersionswasassessedbydifferentialcentrifugalsedimentation（DCS）methods.Casestudy1addressesthevariabilitythatarisesfromvariationswithinoneprotocol,investigatingtheeffectsofdispersionaging,sonicationexposuretime,sonicationinthepresence/absenceofanicebath,materialsubsampling,particleconcentrationandhavingapre-wettingstep.Casestudy2addressesthevariabilitybetweenfourdifferentprotocolsdevelopedthroughpastresearchactivitiesandprojects.Theresultsindicatethatthereisalargedegreeofvariability（relativestandarddeviation（RSD）ofmeanparticlediameter=26%）inthedispersionofTiO2nanomaterialsbetweenthefourdifferentprotocolsstudiedandthatseveralstepsinadispersionprotocolarepotentialsourcesofvariation,withfinalparticleconcentrationbeingthemostsignificant.Theimplicationofthisstudyisclear:forthepurposeofdatacomparability,thereisaneedtoprovidetheexactdetailsofallstepsinvolvedinadispersionprotocol.

简介：

简介：Westudythetransitiontoturbulenceofchannelflowoffinite-sizeparticlesuspensionsatlowvolumefraction,i.e.,Φ≈0.001.ThecriticalReynoldsnumberabovewhichturbulenceissustainedreducestoRe≈1675,inthepresenceoffewparticles,independentlyoftheinitialcondition,avaluelowerthanthatofthecorrespondingsingle-phaseflow,i.e.,Re≈1775.Inthedilutesuspension,theinitialarrangementoftheparticlesisimportanttotriggerthetransitionatafixedReynoldsnumberandparticlevolumefraction.Asinsinglephaseflows,streamwiseelongateddisturbancesareinitiallyinducedintheflow.Ifparticlescaninduceobliquedisturbanceswithhighenoughenergywithinacertaintime,thestreaksbreakdown,flowexperiencesthetransitiontoturbulenceandtheparticletrajectoriesbecomechaotic.Otherwise,thestreaksdecayintimeandtheparticlesimmigratetowardsthechannelcoreinalaminarflow.

简介：Adirect-forcingfictitiousdomain(DFFD)methodisusedtoperformfullyresolvednumericalsimulationsofturbulentchannelflowsladenwithlargeneutrallybuoyantparticles.Theeffectsoftheparticlesontheturbulence(includingthemeanvelocity,therootmeansquare(RMS)ofthevelocityfluctuation,theprobabilitydensityfunction(PDF)ofthevelocity,andthevortexstructures)atafrictionReynoldsnumberof395areinvestigated.Theresultsshowthatthedrag-reductioneffectcausedbyfinite-sizesphericalparticlesatlowparticlevolumesisnegligiblysmall.TheparticleeffectsontheRMSvelocitiesatReτ=395aresignificantlysmallerthanthoseatReτ=180,despitequalitativelythesameeffects,i.e.,thepresenceofparticlesdecreasesthemaximumstreamwiseRMSvelocitynearthewallviaweakeningthelarge-scalestreamwisevortices,andincreasesthetransverseandspanwiseRMSvelocitiesinthevicinityofthewallbyinducingsmaller-scalevortices.TheeffectsoftheparticlesonthePDFsofthefluidfluctuatingvelocitiesnormalizedwiththeRMSvelocitiesaresmall,regardlessoftheparticlesize,theparticlevolumefraction,andtheReynoldsnumber.

简介：有一个更合适的操作员的一个修改规则化算法基于散布原则的Mie在激光粒子sizer从轻散布的数据为粒子尺寸分发(PSD)的倒置被建议。概括交叉验证(GCV)方法和L曲线方法被用于决定规则化参数。连续在松驰上(SOR)反复的方法被用来增加集成的结果的精确和稳定性。模仿的结果基于修改算法在与为九件标准微粒样品，他们的混合物以及三天赋测量的试验性的数据的一个好协议有不规则的形状的微粒材料，显示这个修改规则化方法为从相应轻散布的数据的PSD的模拟不仅可行而且有效。

简介：Athoroughunderstandingonthemechanicalpropertiesofcarbonnanotube(CNT)isessentialinextendingtheadvancedapplicationsofCNTbasedsystems.However,conductingexperimentstoestimatemechanicalpropertiesatthisscaleisextremelychallenging.Therefore,developmentofmechanisticmodelstoestimatethemechanicalpropertiesofCNTsalongwiththeintegrationofexistingcontinuummechanicsconceptsiscriticallyimportant.ThispaperpresentsacomprehensivemoleculardynamicssimulationstudyonthesizedependencyandpotentialfunctioninfluenceofmechanicalpropertiesofCNT.Commonlyusedreactivebondorder(REBO)andadaptiveintermolecularreactivebondorder(AIREBO)potentialfunctionswereconsideredinthisregard.Young'smodulusandshearmodulusofCNTsarederivedbyintegratingclassicalcontinuummechanicsconceptswithmoleculardynamicssimulations.TheresultsindicatethatthepotentialfunctionhasasignificantinfluenceontheestimatedmechanicalpropertiesofCNTs,andtheinfluenceofpotentialfieldismuchhigherwhenstudyingthetorsionalbehaviourofCNTsthanthetensilebehaviour.