简介:Reasonabledenturedesignwillaffectthehealthoforalsupportingtissueandrelatetothesuccessandfailureofprosthodontic.Inordertoinvestigatethestressdistributeoforalsupportingtissueswiththreevariousdesignsunderconditionsofverticalloading,wemeasuredthemodelofthelossoflowerfirstmolarwith3-Dco-ordinatemeasuringapparatus,anddidanaloguedenturedesignwithauto-CADsoft-waresystemincomputer.AllmodelswereanalyzedwithSuper-SAPfiniteelementprogram.Ineachcase,150Nverticalloadingwasappliedonthesecondpremolar,
简介:Itwasrecentlysuggestedthattheperiodicandfractalprecipitaionofcalciumsaltsandproteinsincholesterolgallstonesiscloselyrelatedtotheprocessofstoneformation.Thepresentstudyistomimictheprocessofgallstonegrowthinvitro.Wedemonstrateforthefirsttimethatathree-dimensionalstructureofperiodicrings(Liesegangring)and/orfractalpatternscanbeproducedbymetalionanddeoxycholateprecipitaitonwhicharesimilartogallstones.Precipitationinaperiodicpatternoccursmoreoftenthaninafractalstructure,UsingX-raydiffraction.polarizedlightmicroscope,Fouriertransform-infrared(FT-IR),andextendedX-rayabsorptionfinestructure(EXAFS),westudiedthepatternformationmechanismsofbothtypesofstructure.Theresultsindicatethattherateofnucleationinthecrystalgrowthisacrucialelementofaffectthepatternformation.Thepatternselectionbetweenperiodicandfractaltypedependsonthecrystalgrowthspeedandtherateofnucleation.
简介:Inthispaperthecomplexstructureandpatternofshipsternflowdrivenbymulti-propellersissimulatednumericallybyusingRANSequationswithK-εturbulencemodelandpropellerliftingsurfacetheoryasessentialresearchtoolandcouplingthecomputercodeofshipsternflowtothecomputercodeofpropellerperformancepredictionthroughthemediumofbodyforce.Ashipmodelwithfourpropellersisselectedasthenumericalexample.Detailedcomputationalresultsarepresentedgraphicallyandthequalitativeandquantitativeanalysisismade.Finally,thecomparisonbetweenthecalculatedresultandtheavailableexperimentaldataismade.Theagreementbetweenthemissatisfactory.
简介:Toclarifytheinfluencesofthetipclearanceflowsontheunsteadycavitatingflow,thethree-dimensionalunsteadycavitatingflowsthroughboththetwo-dimensionalcascadesandthethree-dimensionalinducerwithandwithouttipclearanceareperformednumerically.ThegoverningequationsforthecompressiblefluidflowwiththeDESturbulencemodelareemployedwiththeassumptionoftheisentropicprocessofliquidphase.Theevolutionofcavitiesisrepresentedasthesource/sinkofvaporphase.Thebasicequationsinthecurvelinearcoordinatearesolvedbythefinitedifferencemethod.Astheresultsofthethree-dimensionalcavitatingflowsthroughthetwo-dimensionalcascades,thetipclearanceflowsfromthepressuresidetothesuctionsideofthebladeproducesthetipvortexcavitation,whichaffectsthesheetcavitationontheleadingedgeofthenextbladeandenhancestheblockageeffectnearthecasingthantheflowswithouttipclearance.Ontheotherhand,inthecaseofthethree-dimensionalinducer,thelargebackflowcavitationisobservedaroundtheinletoftheinducer,wherethecavitiesaredevelopedonthecasingbythetipclearanceflows.Thelargepressuregradientbetweenthenon-cavitatingpressuresideandthecavitatingsuctionsideenhancesthetipclearanceflows.Thecalculationconsideringthetipclearancereproducesthedevelopedcavitationregionsimilartothatofexperimentalvisualizations.Additionally,thebackflowcavitationrotateswiththespeedslowerthantherotationspeedoftheinducer.Then,therotationofbackflowcavitationcausestheperiodicfluctuationoftheoutletpressuregreaterthanthatoftheinletpressure.
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简介:Inthispaper,asetofclosed-formformulasforvectorFiniteElementMethod(FEM)toanalyzethreedimensionalelectromagneticproblemsispresentedonthebasisofGaussianquadratureintegrationscheme.Byanalyzingtheopenregionproblems,thefirst-orderAbsorbingBoundaryCondition(ABC)isconsideredasthetruncationboundaryconditionandtheequationiscarriedoutinaclosed-form.Basedontheformulas,thehybridExpandedCholeskyMethod(ECM)andMultiFrontalalgorithm(MF)isappliedtosolvefiniteelementequations.Usingtheclosed-formsolution,theelec-tromagneticfieldofthreedimensionaltargetscanbestudiedsententiouslyandaccurately.Simulationresultsshowthatthepresentedformulasaresuccessfullyandconcise,whichcanbeeasilyusedtoanalyzethreedimensionalelectromagneticproblems.
简介:Anewandeffcientthree-dimensionalimplicithybrdschemeforEulerequatiopnsispresented.ThebasicschemeisthecouplingoftheJamesonandTurkel'sLUdecompositionsandProf.ZhangHanxin'sNNDconcept.TheimprovedLUdecompositionsareappliedtodiscretizedtheimplicitpartoftheEulerEquationsandZhang'smodifiedfluxfunctiontocalculatetherighthandsideoperatorsofthehybridscheme,Numericalcalculationsweremadeofsupersonicinletflowswithmixedexternal-internalcompressions,Someofthecomputedresultswerecomparedwithavailablewindtunneldata.
简介:Havingawiderangeofmotion,thecervicalspineisratherpredisposedtotrau-maandotherdisorderswithseriousconsequences.Themotionofcervicalspineisacomplexonecomposedofmicromotions,includinghorizontaldisplacementsalongallthreeaxesandrotationsaroundthemwithsixfreedomdegreesofmovement.Reportonprecisemeasurementofthethree-dimensionalmotionofthecervicalsectionof
简介:Thebandgap,animportantcharacteristicoftheperiodicstructure,isdispersionrelated,whichcanbedesignedbytailoringthelayoutofmaterialswithintheperiodicmicrostructures.Atypicalexampleofaperiodicstructureisphononiccrystals(PnCs),whicharetraditionallyfabricatedfromtwo-phasematerials.Herein,weinvestigatethetopologiesofperiodicthree-phasePnCs.Themicrostructuresofthethree-phasePnCsareoptimizedusingatwo-stagegeneticalgorithm,andthreecasestudiesareproposedtoobtainthefollowing:(1)themaximumrelativebandgapwidth,(2)themaximumabsolutebandgapwidth,and(3)themax-imumbandgapataspecifiedfrequency.Moreimportantly,thethree-phasematerialprovidessignificantadvantagescomparedtothetypicaltwo-phasematerials,suchasalow-frequencybandgap.Thisresearchisexpectedtocontributehighlytovibrationandnoiseisolation,elasticwavefilters,andacousticdevices.
简介:Thecyclicsymmetryandlocalfine-meshtechnologywereadoptedintheestablishmentofnumericalsimulationmodelforinnergearspin-forming.Andtheprocessingexperimentwasproceededtoverifythereliabilityoftheestablishedmodel.Thesimulationresultindicatesthatbesidesradialandaxialflows,therealsoexistsratherlargetangentialflow,whichresultsinanincreaseofformingforceintangentialdirection.Furthermore,theun-uniformdeformationofmetalduringspin-formingwouldcauseformingdefects,suchasunderfillintoothfilletregionandindentationontheoutsidespunpart.
简介:Thispaperdevelopedanewtypeofthreedimensionalinnermicrofintube,Theexperimentalresultsoftheflowpatternsforthehorizontalcondensationinsidethesetubesarereportedinthepaper,Theflowpatternsforthehirizontalcondensationinsidethenewmadetubesaredividedintoannularflowstratifiedflowandintermittentflowwithinthetestconditions.Theexperimentsofthelocalheattransfercoefficientsforthedifferentflowpatternshavebeensystematicallycariedout,Theexperimentsofthelocalheattransfercoefficientschangingwiththevapordrynessfractionhavealsobeencarriedout.Ascomparedwiththeheattransfercoefficientsofthetwodimensionalinnermicrofintubes,thoseofthethreedimensionalinnermicrofintubesincrease47-127%fortheannularflowregion,38-183%forthestratifiedflowand15-75%,fortheintermittentflow,respectively.Theenhancementfactorofthelocalheattransfercoefficientsisfrom1\8-6\9forthevapordrynessfractionfrom0.05to1.
简介:Inthisletterthethree-dimensionalnonlinearHelmholtzequationisinvestigated,whichdescribeselectro-magneticwavepropagationinanonlinearKerr-typemediumsuchthatsixteenfamiliesofnewJacobiellipticfunctionsolutionsareobtained,byusingourextendedJacobianellipticfunctionexpansionmethod.Whenthemodulusm→1or0,thecorrespondingsolitarywavesincludingbrightsolitons,darksolitonsandnewlinesolitonsandsinglyperiodicsolutionscanbealsofound.
简介:Usingthreedimensional(3D)viscoelasticfiniteelementmethod(FEM)westudythedynamicevolutionpatternofthecoseismicchangeofCoulombfailurestressandpostseismicchange,ontimescaleofhundredsyears,ofrheologicaleffectinducedbytheMS=7.2XingtaiearthquakeonMarch22,1966.Then,wesimulatethecoseismicdisturbanceinstressfieldinNorthChinaanddynamicchangerateonone-yearscalecausedbytheXingtaiearth-quakeandTangshanearthquakeduring15yearsfrom1966to1980.Finally,wediscussthetriggeringofastrongearthquaketoanotherfuturestrongearthquake.
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简介:Thepaperpresentsthe3DfiniteelementsimulationoftidalflowandSedimenttransportintheestuarineregionoftheHaiheriver.Theproposedmodeladoptssigma-transformationofthehydrodynamicandsedimenttransportequations.Thehydrodynamicandsedimenttransportmodelsareverifiedincaseofasimpletestproblemforwhichanalyticalsolutionsareavailable.FinallythemodelsareappliedtomuddyHaiheriverestuaryofNorthChinaanditisclaimedthathydrodynamicandsedimenttransportmodelsgiveareliablecomparisonwiththeobservedfielddata.However,therearecertaindiscrepancies,andsomereasonablequestionsregardingthepresentstate-of-art,inthemodelingofthree-dimensionalmultilevelhydrodynamicsandsedimenttransport,whichareprovidedbelowforanswer.