简介:Inthispaper,weconsiderthenonsymmetricalhalf-planeprediction.Apredictiontheoreticproofofthefundamentalformulaaboutonesteppredictionerrorisgiven.AWold-typedecompositionanditsspectralrepresentationtheoremareproved.Spectralextractionproblemsofthehalf-planeinnova-tionsanditssingularcomponentsareinvestigated.
简介:Let{N(t),t≥0}bethenonhomogeneousPoissonprocesswithcumulativeintensityparameterΛ(t),{δt,t≥0}theageprocess,and{yi,t≥0)theresiduallifetimeprocess.Inthepresentpapertheexpressionsofn-dimensionalsurvivaldistributionfunctionsoftheprocesses{δi}and{yi},andtheirLebesguedecompositionsarederived.
简介:Thelifetimeofanartificialsatellitemovinginthecircularorbitundertheactionofnonuniformrotatingatmosphericdragisstudiedfromanenergypointofviewinthispaper.Theangularvelocityofatmosphericrotationdecreaseswithheightaccordingtohydrodynamics.Theatmosphericdensitydecreaseswithheightaccordingtotheexponentialformula.Theexpressionforthelifetimeofasatelliteintheinstantaneouscircularorbitintheabove-mentionedrotatingatmosphericmodelisderived,andthenumericalestimationforthelifetimeofaconcretesatellitehasbeenmade.Theresultshowsclearlythatthesatellitelifetimecalculatedbythispaperisshorterthanthatcalculatedbytheuniformrotatingatmosphericmodel.
简介:Emission Time of Light Particles and Lifetime of Hot Nuclei Following Binary FissionEmissionTimeofLightParticlesandLifetimeof...
简介:Inthispaper,thetheoryofQuasi-steadyisappliedtothecalculationsofturbochargersmatchingtothedieselenginesandperformanceprediction.Theengineperformancepredictionprogramswritteninlanguaechavebeenusedforcalculationsofvariousturbochargeddieselengines.Ithasbeenconfirmedbythecomparisonswithexperimentaldatathattheresultsofthecalcuationarereasonable,reliableandsatisfiedfortheengineeringapplications.
简介:Afugacitymodelwasdevelopedforpredictionofmixedrefrigerantgashydratesformationconditionsbasedonthemoleculecongregationandsolutiontheories.Inthismodel,gashydrateswereregardedasnon-idealsolidsolutioncomposedofwatergroupsandguestmolecules,andtheexpressionsoffugacityofguestmoleculesinhydratephasewasproposedaccordingly.Ithasbeenshownthatthedevelopedmodelcanindicatesuccessfullytheeffectofguest-guestmoleculeinteraction.Theresultsshowedthatthemodelcandescribebetterthecharacteristicsofphaseequilibriumofmixedrefrigerantgashydratesandpredictionsareingoodagreementwithexperimentaldata.
简介:TheeffectsofF^-ionsinagermanium-lead-telluriteglasssystemonthespectralandpotentiallaserpropertiesoftheYb^3+areinvestigated.Theabsorptionspectra,lifetimes,theemissioncross-sectionsandtheminimumpumpintensitiesoftheglasssystemwithandwithoutF^-ionshavebeenmeasuredandcalculated.TheresultsshowthatthefluorescencelifetimeandtheminimumpumpintensityofYb^3+ionsincreaseevidently,whichindicatesthatgermanium-lead-oxyfluoridetelluriteglassisapromisinglaserhostmatrixforhighpowergeneration.FT-IRspectrawereusedtoanalysetheeffectofF^-ionsonOH^-groupsinthisglasssystem.AnalysisdemonstratesthatadditionoffluorideremovestheOH^-groupsandresultsinimprovementoffluorescencelifetimeofYb^3+.
简介:Amodelwasestablishedtopredictcondensationheattransfercoefficientonhorizontalrectangularfinnedtube.Drop-Offzoneatthetubebottomwasconsideredanddetermined,theknownHonda(andOwen)expressionofretentionanglewasalsomodifiedasaresultofconsideringdrop-offzone.Heatfluxonfintipsintheunfloodedregion,finflanks,finspacingsandfintipsinthefloodedregionwereanalyzedrespectively.COndensationonfintipsinemphasizedbyconsideringthevariationoffilmthicknessalongcircumferenceaswellashorizontally.FInefficiencywasconsideredincalculation.Thepredictionresultswerecomparedwithseveralresearchers'experimentaldataforthreekindsofworkingfluidsonsevendifferenttubegeometriesandforvarioustemperaturedifferences,Thesedataunderabout60testconditionswerepredictedwithdiscrepancyof±10%.PredictionbythepresentmodelforsteamandR-113condensationwerecomparedwithpreviousmodels.
简介:Hydrodynamicandthermalcharacteristicsinapipewithsinusoidalwavysurfaceforsteadylaminarflowareinvestigatednumericallyinthepresentstudy.TheintegralformsofgoverningequationsarediscretizedusingcontrolvolumebasedFinitevolumemethodwithcollocatedvariablearrangement.SIMPLEalgorithmisusedandTDMAsolverisappliedforsolutionofsystemofequations.Apipeoflengthequalto4λisconsidered.Effectofsurfacewaviness,determinedbywavelength-amplituderatioλ/a(=L^*),onflowandthermalfieldispresented.ThesimulationworkhasbeencarriedoutforL^*=11.0-30.0foraReynoldsnumberrange50to2000.Resultsarepresentedintheformofstreamfunction,isothermallines,velocityandvorticityprofiles,changeofmeanfrictionfactor,variationinskinfriction,localandaverageNusseltnumberwithReynoldsnumber,wavenumber(n)andL^*.Foraparticulargeometry,lengthofcirculationzoneincreaseswithreynoldsnumberandapproachesalimitingvalueforhigherReynoldsnumber.Wallshearstressinthebulgepartofthechannelshowssmallervaluesthataffectlargely.therateofheattransferandNusseltnumbershowsminimumvaluesinthisregion.Thiscirculationzonedrasticallyincreaseswiththeincreaseofsurfacewavinessshowinghighmeanfrictionfactorperwavelength.MeanfrictionfactorinverselyvarieswithReynoldsnumber.Acorrelationisproposedforcalculatingfrictionfactorintheformf=C/(Re)^m,where‘C’and‘m’representstwopolynomialsofdegree4and2respectivelyandarefunctionofL^*.Higherwavinessofthesurfaceshowsthehigherheattransferratethanlowerwaviness.Heattransferratefallsalmostexponentiallyalongtheaxialdirectionwiththeincreaseofwavenumber.
简介:Thephenomenonofearingisinvestigatedinthepresentstudybasedonthetheoryofcrystalplasticitywiththedynamicexplicitfiniteelementprogramdeveloped.FirstlytextureanalysisiscarriedoutofrolledaluminiumalloyA15052bymeansofX-raytechnique.Thenfromthetexturecoefficientsananalyticalexpressionfortheorientationdistributionfunction(ODF)isderivedmakinguseofthecomputeralgebraiclanguageMathematica4.0,whichmakesiteasiertodiscretizetheODFintoaseriesofEuleriananglesrepresentingthedistributionoflatticesandfurtherthepreferredorientation(texture)ofcrystalsoftheoriginalsheets.Forthepolycrystalmodel,thematerialisdescribedusingcrystalplasticitywhereeachmaterialpointinthesheetisassumedtobeapolycrystallineaggregateofaverylargenumberofface-centeredcubic(FCC)grainswitheachgrainmodelledasanFCCcrystalwith12distinctslipsystems.ThemodifiedTaylortheoryofcrystalplasticityisusedandonlytheinitialtextureistakenintoconsiderationduringlargeplasticdeformation.Numericalsimulationofearinghasbeenperformedforanaluminiumsheetwithtextureandonewithcrystalsexhibitingrandomdistributiontodemonstratetheeffectoftextureofmaterialsontheirplasticanisotropyandformability.
简介:平淡的波浪重叠途径不能在一块协调的声学的地的重建和预言被使用,因为分开单个来源产生的压力是不可能的。根据协调的声学的地的重叠理论,一个新奇方法基于联合波浪重叠途径被开发重建并且由造匹配在全息图表面和来源之间的矩阵的联合压力预言协调的声学的地。方法能重建个人的表面的声学的信息采购原料,并且预言也从每来源和全部的协调的声学的地罐头散发的声学的地自发地被计算是可能的。试验性、数字的模拟结果证明这个方法能有效地解决holographic重建和协调的声学的地的预言,它能也被用作一种协调的声学的地分离技术。这个新奇方法上的学习扩大声学的雷射摄影术技术的应用程序范围。
简介:Inthispaperwestudytheproximalpointalgorithm(PPA)basedpredictioncorrection(PC)methodsformonotonevariationalinequalities.Eachiterationofthesemethodsconsistsofapredictionandacorrection.ThepredictorsareproducedbyinexactPPAsteps.ThenewiteratesarethenupdatedbyacorrectionusingthePPAformula.Wepresenttwoprofitfunctionswhichservetwopurposes:Firstweshowthattheprofitfunctionsaretightlowerboundsoftheimprovementsobtainedineachiteration.Basedonthisconclusionweobtaintheconvergenceinexactnessrestrictionsforthepredictionstep.Secondweshowthattheprofitfunctionsarequadraticallydependentuponthesteplengths,thustheoptimalsteplengthsareobtainedinthecorrectionstep.Inthelastpartofthepaperwecomparethestrengthsofdifferentmethodsbasedontheirinexactnessrestrictions.
简介:Theinitial-boundaryvalueproblemofBurgersequationisconsidered.Aprediction-correctionLegendrespectralschemeisproposed.Itpossessestheaccuracyofsecondorderintimeandhigherorderinspace.Thenumericalexperimentsshowthehighaccuracyofthisapproach.
简介:Withrespecttoobtainingtheeffectiveelasticmoduliofthecomposite,thepresenttheorydif-fersfrombothEshelby’sequivalentinclusionmethodandHill’sself-consistentone,bothofwhichonlyconsid-erthemechanicalpropertiesofthematrixandinclusions(fibers).Infact,theinclusion-inclusioninteractionismorepronouncedwhenthevolumefractionofinclusionsofthecompositeincreases.Hence,inthispapertheeffectiveelasticmoduliofthecompositearederivedbytakingintoaccounttheshapes,sizesanddistributionofinclusions,andtheinteractionsbetweeninclusions.Inaddition,itismoreconvincingtoassumeshort-fibersascylindricalinclusionsasinthepresentpaperthanasellipsoidalonesasinothers.Finally,numericalre-sultsaregiven.