简介：Thispaperaimsatdevelopingastochastic-elasticmodelofasoftelasticbodyadheringonawavysurfaceviaapatchofmolecularbonds.Theelasticdeformationofthesystemismodeledbyusingcontinuumcontactmechanics,whilethestochasticbehaviorofadhesivebondsismodeledbyusingBell'stypeofexponentialbondassociation/dissociationrates.Itisfoundthatforsufficientlysmalladhesionpatchsizeorstressconcentrationindex,theadhesionstrengthisinsensitivetothewavelengthbutdecreaseswiththeamplitudeofsurfaceundulation,andthatforlargeadhesionpatchsizeorstressconcentrationindex,thereexistoptimalvaluesofthesurfacewavelengthandamplitudeformaximumadhesionstrength.

简介：Theobjectiveofthisstudyistoinvestigatethehemodynamicsinpatient-specificthoracicaorticaneurysmanddiscussthereasonforformationofaorticplaque.A3-Dimensionalpulsatilebloodflowinthoracicaortawithafusiformaneurysmand3mainbranchedvesselswasstudiednumericallywiththeaverageReynoldsnumberof1399andtheWomersleynumberof19.2.Basedontheclinical2-DimensionalCTslicedata,thepatient-specificgeometrymodelwasconstructedusingmedicalimageprocesssoftware.Un...

简介：Bacterialflagellarfilamentcanundergoastress-inducedpolymorphicphasetransitioninbothvitroandvivoenvironments.Thefilamenthas12differenthelicalforms(phases)characterizedbydifferentpitchlengthsandhelixradii.Whensubjectedtothefrictionalforceofflowingfluid,thefilamentchangesbetweenaleft-handednormalphaseandaright-handedsemi-coiledphaseviaphasenucleationandgrowth.Thispaperdevelopsnon-localfiniteelementmethod(FEM)tosimulatethephasetransitionunderad...

简介：ThespecificsignofReynoldsstressintheboundarylayeronaflatplateatzeroincidenceisnewlyinterpretedinpresentpaperbasedonthetheoryofvortex-inducedvortex.Itavoidssomeproblemsappearedinatraditionalexplanation,onthebasisofrelationshipbetweenmeanandfluctuatingflowsduetothetransportofmomentum.Throughtheanalysisoflocalflowfieldintheimmediateneighborhoodofwall,thecharacteristicsofReynoldsstressareidentifiedthroughintroducingturbulence-inducedsmall-scalestreamwiseeddiesabovetheflatplate.ThepositiveReynoldsstressistheoreticallyverified.AndsuchnewinterpretationillustratesthatthegenerationofReynoldsstress,aswellasfluctuatingvelocity,isintrinsicallyindependentofthemeanflow.Butitsspecificsignwouldbedeterminedbythemeanflowduetotheinertialforces.Otherfeatures,suchastheintensityrelationshipamongthreecomponentsoffluctuatingvelocity,arealsopresented.

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简介：Abriefaccountisprovidedoncrack-tipsolutionsthathaverecentlybeenpublishedintheliteraturebyemployingtheso-calledGRADELAmodelanditsvariants.TheGRADELAmodelisasimplegradientelasticitytheoryinvolvingoneinternallengthinadditiontothetwoLame'constants,inanefforttoeliminateelasticsingularitiesanddiscontinuitiesandtointerpretelasticsizeeffects.Thenon-singularstrainsandnon-singular(butsometimessingularorevenhypersingular)stressesderivedthiswayunderdifferentboundaryconditionsdifferfromeachotherandtheirphysicalmeaninginnotclear.Thisisdiscussedwhichfocusontheformandphysicalmeaningofnon-singularsolutionsforcrack-tipstressesandstrainsthatarepossibletoobtainwithintheGRADELAmodelanditsextensions.

简介：这个工作学习在横梁的免费结束由非一致地分布式的连续负担和集中的负担组成的受到联合装载的苗条、非棱柱的伸臂横梁的大偏转。伸臂的材料被假定非线性地有弹性。在在张力、压缩的领域的应力和紧张之间的不同非线性的关系被考虑。数字答案的精确性被从以前的研究并且与一个实验室实验把他们与结果作比较评估。

简介：Anewalgorithmforsolvingthethree-dimensionalelasticcontactproblemwithfrictionispresented.Thealgorithmisanon-interiorsmoothingalgorithmbasedonanNCPfunction.Theparametricvariationalprincipleandparametricquadraticprogrammingmethodwereappliedtotheanalysisofthree-dimensionalfrictionalcontactproblem.Thesolutionofthecontactproblemwasfinallyreducedtoalinearcomplementarityproblem,whichwasreformulatedasasystemofnonsmoothequationsviaanNCP-function.Asmoothingapproximationtothenonsmoothequationswasgivenbytheaggregatefunction.ANewtonmethodwasusedtosolvetheresultingsmoothingnonlinearequations.Thealgorithmpresentediseasytounderstandandimplement.ThereliabilityandefficiencyofthisalgorithmaredemonstratedbothbythenumericalexperimentsofLCPinmathematicalwayandtheexamplesofcontactproblemsinmechanics.

简介：Non-transferreddcarcplasmageneratorsarewidelyusedinmaterialsprocessing.Theyaregenerallyconsideredsteadily-operatingdevises.However,unsteadyphenomenadoexistinthem,andmaycausenon-idealeffectsinprocesseswhichrequirehighcontrollabilityandreproducibility.Theseunsteadyphenomenacancauseparameterfluctuationsinthearcandtheplasmajet,someofwhichhavebeenstudiedinrecentyears.Severaltypesandmechanismsofthesephenomenahavebeenidentified.Thispaperreviewst...

简介：有在粒子沉重的狂暴的隧道流动的热转移上的不同的特定的热的惯性的粒子的效果用直接数字的模拟(DNS)和追踪方法的Lagrangian粒子被学习。模拟使用一个双向联合模型考虑在粒子和骚乱之间的动量和热相互作用。温度回答的学习表演与不同的特定的热粒子和没有粒子的流动显示粒子沉重的流动之间的差别，显示特定的热是的粒子在粒子沉重的流动影响热转移进程的一个重要因素。粒子沉重的流动的热转移能力逐渐地随粒子的增加增加特定的热，这被发现。这由于对热转移的粒子增加的积极贡献。另外，粒子沉重的流动的Nusselt数字与没有粒子的流动的相比。有大特定的热的粒子加强狂暴的流动的热转移，这被发现，当那些与小特定的热削弱狂暴的流动的热转移时。

简介：Aninvestigationisdescribedforinstabilityproblemofflowthroughapipeofcircularcross-section.Asadisturbancemotion,weconsiderageneralnon-axisymmetricmode.Anassociatedamplitudeormodulationequationhasbeenderivedforthisdisturbancemotion.Thisequationbelongstoadiffusiontype.ThecoefficientofitcanbenegativewhileReynoldsnumberincreases,becauseofthecomplexinteractionbetweenmoleculardiffusionandconvection.Thenegativediffusivity,whenitoccurs,causesaconcentrationandfocussingofenergywithindecayingslugs,actingasaroleofreversingnaturaldecays

简介：ＮＯＮ－ＳＹＭＭＥＴＲＩＣＡＬＬＡＲＧＥＤＥＦＯＲＭＡＴＩＯＮＯＦＡＳＨＡＬＬＯＷＴＨＩＮＳＰＨＥＲＩＣＡＬＳＨＥＬＬＷａｎｇＸｉｎｚｈｉ（王新志）ＲｅｎＤｏｎｇｙｕｎ（任冬云）ＷａｎｇＬｉｎｘｉａｎｇ（王林祥）ＹｅｈＫａｉｙｕａｎ（叶开沅）（Ｇａｎ...

简介：Inthispaperathreedegreesoffreedomautoparametricsystemwithlimitedpowersupplyisinvestigatednumerically.Thesystemconsistsofthebody,whichishungonaspringandadamper,andtwopendulumsconnectedbyshapememoryalloy(SMA)spring.Shapememoryalloyshaveabilitytochangetheirmaterialpropertieswithtemperature.ApolynomialconstitutivemodelisassumedtodescribethebehavioroftheSMAspring.Thenon-idealsourceofpoweraddsonedegreeoffreedom,sothesystemhasfourdegreesoffreedom.Theequationsofmotionhavebeensolvednumericallyandpseudoelasticeffectsassociatedwiththemartensiticphasetransformationarestudied.Itisshownthatinthistypesystemonemodeofvibrationsmightexciteordampanothermode,andthatexceptdifferentkindsofperiodicvibrationstheremayalsoappearchaoticvibrations.Fortheidentificationoftheresponsesofthesystem’svarioustechniques,includingchaostechniquessuchasbifurcationdiagramsandtimehistories,powerspectraldensities,Poincar`emapsandexponentsofLyapunovmaybeused.

简介：Bothclinicalandpostmortemstudiesindicatethat,inhumans,thecarotidsinusofthecarotidarterybifur-cationisoneofthefavoredsitesforthegenesisanddevelop-mentofatheroscleroticlesions.Hemodynamicfactorshavebeensuggestedtobeimportantinatherogenesis.Tounderstandthecorrelationbetweenatherogenesisandfluiddynamicsinthecarotidsinus,thebloodflowinarterywassimulatednumerically.Inthosestudies,thepropertyofbloodwastreatedasanincompressible,Newtonianfluid.Infact,however,thebloodisacomplicatednon-Newtonianfluidwithshearthinningandviscoelasticproperties,especiallywhentheshearrateislow.Avarietyofnon-Newtonianmod-elshavebeenappliedinthenumericalstudies.Amongthem,theCassonequationwaswidelyused.However,theCas-sonequationagreeswellonlywhentheshearrateislessthan10s~(-1).Theflowfieldofthecarotidbifurcationusuallycoversawiderangeofshearrate.WethereforebelievethatitmaynotbesufficienttodescribethepropertyofbloodonlyusingtheCassonequationinthewholeflowfieldofthecarotidbifurcation.Inthepresentstudy,threedifferentbloodconstitutivemodels,namely,theNewtonian,theCas-sonandthehybridfluidconstitutivemodelswereusedintheflowsimulationofthehumancarotidbifurcation.Theresultswerecomparedamongthethreemodels.TheresultsshowedthattheNewtonianmodelandthehybridmodelhadverysimilardistributionsoftheaxialvelocity,secondaryflowandwallshearstress,buttheCassonmodelresultedinsignificantdifferencesinthesedistributionsfromtheothertwomod-els.ThisstudysuggeststhatitisnotappropriatetoonlyusetheCassonequationtosimulatethewholeflowfieldofthecarotidbifurcation,andontheotherhand,Newtonianfluidisagoodapproximationtobloodforflowsimulationsinthecarotidarterybifurcation.

简介：Non-sphericalmicronandnano-sizedparticlesandtheircompositeshavebecomeessentialinselectapplicationareasofoptics,wearresistance,personnelprotection,chemicalmechanicalpolishing,andbiomedicine.Inthispaper,thesynthesisofcompositeandceramicnon-sphericalparticlesusingstopflowlithographyisreported.Precursorsuspensionsofpoly（ethyleneglycol）diacrylate,2-hydroxy-2-methylpropiophenoneandSiO2orAl2O3areprepared.Theprecursorsuspensionflowsthroughamicrofluidicdevicemountedonanuprightmicroscopeandispolymerizedinanautomatedprocess.Aphotomaskpatternedwithtransparentgeometricfeatures,whichdefinethecross-sectionalshapesoftheparticles,maskstheUVlighttosynthesizemicronsizedparticles.Particleswithaxialdimensionsrangingfrom35to167μmweresynthesized.Controlofdevicechanneldepthandobjectivelensmagnificationenablesthemanipulationoftheparticlesize.Compositeparticlesintriangular,square,pentagonal,hexagonal,andcircularcrosssectionsweresynthesized.Subsequently,thetransformationofthecompositeparticlesintothecorrespondingmetaloxideparticleswasachievedthroughpolymerburn-offandsintering.

简介：ThereareNdomainsDj.（j=0,1,……,N-1）ofdifferentphysicalparametersinthewholespaceandtheirinterfaces.Sjj+1arenon-horizontallysmoothcurvedsurfaces.ThefollowingboundaryproblemiscalledHelmholtzboundaryproblem:Theanalyticalsolutionoftheaboveproblemisgiveninthispaper.

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简介：ＮＯＮ－ＬＩＮＥＡＲＥＬＡＳＴＩＣＴＨＥＯＲＹＯＦＲＥＣＴＡＮＧＵＬＡＲＲＥＴＩＣＵＬＡＴＥＤＳＨＡＬＬＯＷＳＨＥＬＬＳＴＲＵＣＴＵＲＥＳＮｉｅＧｕｏ－ｈｕａ（聂国华）（ＤｅｐａｒｔｍｅｎｔｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈａｎｉｃｓ，ＴｏｎｇｊｉＵ...

简介：Inoffshoreengineeringdesign,itisconsiderablysignificanttohaveanadequatelyaccurateestimationofmarineenvironmentalparameters,inparticular,theextremewindspeedoftropicalcyclone(TC)withdifferentreturnperiodstoguaranteethesafetyinprojectedoperatinglifeperiod.Basedonthe71-year(1945–2015)TCdataintheNorthwestPacific(NWP)bytheJointTyphoonWarningCenter(JTWC)ofUS,anotablegrowthoftheTCintensityisobservedinthecontextofclimatechange.Thefactimpliesthatthetraditionalstationarymodelmightbeincapableofpredictingparametersintheextremeevents.Therefore,anon-stationarymodelisproposedinthisstudytoestimateextremewindspeedintheSouthChinaSea(SCS)andNWP.Wefindthattheextremewindspeedsofdifferentreturnperiodsexhibitanevidentenhancementtrend,forinstance,theextremewindspeedswithdifferentreturnperiodsbynonstationarymodelare4.1%–4.4%higherthanstationaryonesinSCS.Also,thespatialdistributionofextremewindspeedinNWPhasbeenexaminedwiththesamemethodologybydividingthewestseaareasoftheNWP0°–45°N,105°E–130°Einto45subareasof5°×5°,whereoilandgasresourcesareabundant.Similarly,remarkablespacialin-homogeneityintheextremewindspeedisseeninthisarea:theextremewindspeedwith50-yearreturnperiodinthesubarea(15°N–20°N,115°E–120°E)ofZhongshaandDongshaIslandsis73.8m/s,whilethatinthesubareaofYellowSea(30°N–35°N,120°E–125°E)isonly47.1m/s.Asaresult,thepresentstudydemonstratesthatnon-stationaryandin-homogeneouseffectsshouldbetakenintoconsiderationintheestimationofextremewindspeed.

简介：Thispaperpresentsasimpleapproachforimprovingtheperformanceoftheweightedessentiallynonoscillatory(WENO)finitevolumeschemeonnon-uniformgrids.ThistechniquereliesonthereformulationofthefifthorderWENO-JS(WENOschemepresentedbyJiangandShuinJ.Comput.Phys.126:202–228,1995)schemedesignedonuniformgridsintermsofonecell-averagedvalueanditsleftand/orrightinterfacialvaluesofthedependentvariable.Theeffectofgridnon-uniformityistakenintoconsiderationbyaproperinterpolationoftheinterfacialvalues.Onnonuniformgrids,theproposedschemeismuchmoreaccuratethantheoriginalWENO-JSscheme,whichwasdesignedforuniformgrids.Whenthegridisuniform,theresultingschemereducestotheoriginalWENO-JSscheme.Inthemeantime,theproposedschemeiscomputationallymuchmoreefficientthanthefifth-orderWENOschemedesignedspecificallyforthenon-uniformgrids.Anumberofnumericaltestcasesaresimulatedtoverifytheperformanceofthepresentscheme.