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简介:TheEffectofWeakShear-inducedMotiononBrownianCoagulationofAerosolParticlesWinjingsons(C.S.Win)(温景嵩)(Departmentofphysics,Nankai...
简介:TheevolutionequationsofmomentsfortheBrowniancoagulationofnanoparticlesinbothcontinuumandfreemoleculeregimesareanalyticallystudied.TheseequationsarederivedusingaTaylor-expansiontechnique.Theself-preservingsizedistributionisinvestigatedusinganewlydefineddimensionlessparameter,andtheasymptoticvaluesforthisparameteraretheoreticallydetermined.Thedimensionlesstimerequiredforaninitialsizedistributiontoachieveself-preservationisalsoderivedinbothregimes.Oncethesizedistributionbecomesself-preserving,thetimeevolutionofthezerothandsecondmomentscanbetheoreticallyobtained,anditisfoundthatthesecondmomentvarieslinearlywithtimeinthecontinuumregime.Equivalentequations,ratherthantheoriginalonesfromwhichtheyarederived,canbeemployedtoimprovetheaccuracyoftheresultsandreducethecomputationalcostforBrowniancoagulationinthecontinuumregimeaswellasthefreemoleculeregime.
简介:ACFDsimulationisperformedforaparticle-ladenplanarjetflow.TheReynoldsnumberis8300,andtheinitialparticlediameteris1μm.LargeEddySimulation(LES)isemployedtocalculatetheflowfield,andtheTaylor-seriesexpansionmomentmethod(TEMOM)isadoptedtodealwiththebalanceequationofparticlecoagulationandbreakage.Theshear-inducedcoagulationkernel,power-lawbreakagekernelandsymmetricfragmentdistributionfunctionareinvolved.Thepredictionofthedistributionofthemeanstreamwisevelocityofthejetisingoodagreementwithexperimentaldata.Theevolutionofparticlenumberconcentration,volumeconcentration,polydispersity,particlediameterandstandardgeometricdeviationisdiscussedindetail.Theresultsshowthatasthejettravelsdownstream,theparticlenumberconcentrationandvolumeconcentrationdecrease,whiletheirspansbecomewider.Thepolydispersityandparticlediameterareverylargeintheshearlayersattheupstreamandinthecoreofvortexstructuresatthedownstream.Theparticlestandardgeometricdeviationchangeswithintherangeof1.32≤σg≤1.96,andincreasessharplyintheshearlayers.Allvariablesapproachthesteady-stateastimeprogresses.
简介:Theroleofpulseparametersonnanoparticlepropertyisinvestigatedself-consistentlybasedonacoupleoffluidmodelandaerosoldynamicsmodelinacapacitivelycoupledparallel-plateacetylene(C2H2)discharge.Inthismodel,themasscontinuityequation,momentumbalanceequation,andenergybalanceequationforneutralgasaretakenintoaccount.Thus,thethermophoreticforceariseswhenagastemperaturegradientexists.Thetypicalresultsofthismodelarepositiveandnegativeiondensities,electronimpactcollisionsrates,nanoparticledensity,andchargedistributions.Thesimulationisperformedfordutyratio0.4/0.7/1.0,aswellaspulsemodulationfrequencyfrom40kHzto2.7MHzforpureC2H2dischargesatapressureof500mTorr.Wefindthatthepulseparameters,especiallythedutyratio,haveagreataffectonthedissociativeattachmentcoefficientandthenegativedensity.Moreimportantly,bydecreasingthedutyratio,nanoparticlesstarttodiffusetothewall.Undertheactionofgasflow,nanoparticledensitypeakiscreatedinfrontofthepulseelectrode,wherethegastemperatureissmaller.
简介:BackgroundAdvancedpracticenursetransitionalcarehasbeenproofedtobeimportantforolderadultswithchronicconditions.However,sucheffectivenesshasneverbeenstudiedinthemanagementofappropriateWarfarinuseinclinicalpractice.MethodsAtotalof97patientswererandomlydistributedintocontrolgroupwhoreceivedusualcare,andinterventionalgroupwhoreceivedtransitionalcareprovidedbyAPNs.A12-monthobservationofbothgroupswererecordedbyphysiciansandAPNsandtheimpactofAPNsonthemanagingofWarfarintherapywasalsoevaluatedbasedontimeinthetherapeuticrange(TTR).ResultsAPNstransitionalcaresignificantly(P<0.01)improvedpatients’adherence,increasedTTRandhighTTRratiocomparedwithcontrolgroup.Re-admissionduetostrokewassignificantly(P<0.01)reducedbyAPNstransitionalcare.ConclusionAPNstransitionalcareimprovespatients’knowledgeonAFandreducesstrokerisk.ThecurrentresearchstronglysuggestthenecessityofAPNstransitionalinterventionalinmanaginganticoagulationtherapyinAFpatientsinChina.