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：Threetypesofplasmaionsourcesdesigned,manufacturedandoptimizedintheAcceleratorsandIonSourcesDepartment,NuclearResearchCenter,AtomicEnergyAuthorityareintroduced.Differentmeanswereinvestigatedtogeneratethedischargecurrentandionbeamcurrentextractedfromtheplasma.ThevariousplasmasdescribedincludeaDCglowdischargeplasma,anarcdischargeplasmaandaradiofrequencydischargeplasma.

简介：Theinstabilityofterahertz(THz)plasmawavesintwo-dimensional(2D)quantumelectrongasinananometerfieldeffecttransistor(FET)withasymmetricalboundaryconditionshasbeeninvestigated.WeanalyzeTHzplasmawavesoftwopartsofthe2Dquantumelectrongas:gatedandungatedregions.Theresultsshowthattheradiationfrequencyandtheincrement(radiationpower)in2Dungatedquantumelectrongasaremuchhigherthanthatin2Dgatedquantumelectrongas.Thequantumeffectsalwaysenhancetheradiationpowerandenlargetheregionofinstabilityinbothcases.Thisallowsustoconcludethat2Dquantumelectrongasinthetransistorchannelisimportantfortheemissionanddetectionprocessandbothgatedandungatedpartstakepartinthatprocess.

简介：Wedevelopedaone-dimensionalhybridmodeltosimulatetheDC/RFcombineddrivencapacitivelycoupledplasmaforargondischarges.ThenumericalresultsareusedtoanalyzetheinfluenceoftheDCsourceontheplasmadensitydistribution,ionenergydistributions(IEDs)andionangledistributions(IADs)onboththeRFandDCelectrodes.TheincreaseinDCvoltagedrivesmorehigh-energyionstotheelectrodeappliedtotheDCsource,whichmakestheIEDsattheDCelectrodeshifttowardshigherenergy,andthepeaksintheIADsshifttowardssmallangleregions.Atthesametime,italsodecreasestheionenergyattheRFelectrodeandenlargestheincidentanglesoftheions,whichstriketheRFelectrode.

简介：Ionopticsisacriticalcomponentofionthrusters.Atwo-dimensionalaxisymmetricmodelisdevelopedtostudythecharacteristicsofthree-gridelectroncyclotronresonanceionthrusteroptics.Thecodeisbasedonaparticle-in-cellcombinedwiththeMonteCarlocollisionmethodtosimulateiondynamicsandcharge-exchangeprocessesinthegridregion.Thesimulationresultsshowthatthemodecangiveareasonableestimateofthephysicscharacteristicsoftheionoptics.Thedesignoftheionopticssatisfiestherequirementofpreventingelectronbackstreaming.Charge-exchangeionscancausedamagetothegrids,especiallytotheacceleratorgrid.'Barrel'erosioncanincreasetheacceleratorgridapertureradiusatarateof1.91×10~(-11)m/s,whilethedeceleratorgridplaysanimportantroleinreducing'pits-and-grooves'erosion.

简介：Adirect-currentairplasmajetoperatedunderwaterpresentsthreestablemodesincludinganintermittently-pulseddischarge,aperiodically-pulseddischargeandacontinuousdischargewithincreasingthepowervoltage.Thethreedischargemodeshavedifferentappearancesfortheplasmaplumes.Moreover,gapvoltage-currentcharacteristicsindicatethatthecontinuousdischargeisinanormalglowregime.Spectrallinesfromreactivespecies(OH,N_2,N_2~+,H_α,andO)havebeenrevealedintheemissionspectrumoftheplasmajetoperatedunderwater.SpectralintensitiesemittedfromOHradicalandoxygenatomincreasewithincreasingthepowervoltageorthegasflowrate,indicatingthatreactivespeciesareabundant.Thesereactivespeciescausethedegradationofthemethylenebluedyeinsolution.Effectsoftheexperimentalparameterssuchasthepowervoltage,thegasflowrateandthetreatmenttimeareinvestigatedonthedegradationefficiency.Resultsindicatethatthedegradationefficiencyincreaseswithincreasingthepowervoltage,thegasflowrateorthetreatmenttime.Comparedwithdegradationintheintermittently-pulsedmodeortheperiodically-pulsedone,itismoreefficientinthecontinuousmode,reaching98%after21mintreatment.

简介：Atwo-dimensionalhybridcodeisdevelopedtomodelthetransportofahigh-currentelectronbeaminadenseplasmatarget.Thebeamelectronsaretreatedasparticlesanddescribedbyparticle-in-cellsimulationincludingcollisionswiththetargetplasmaparticles.Thebackgroundtargetplasmaisassumedtobeastationaryfluidwithtemperaturevariations.Thereturncurrentandtheself-generatedelectricandmagneticfieldsareobtainedbycombiningAmpere’slawwithoutthedisplacementcurrent,theresistiveOhm’slawandFaraday’slaw.Theequationsaresolvedintwo-dimensionalcylindricalgeometrywithrotationalsymmetryonaregulargrid,withcenteredspatialdifferencingandfirst-orderimplicittimedifferencing.Thealgorithmsimplementedinthecodearedescribed,andanumericalexperimentisperformedforanelectronbeamwithMaxwelliandistributionejectedintoauniformdeuterium-tritiumplasmatarget.

简介：Ananalyticalstudyispresentedonthemodaldispersioncharacteristics,groupvelocity,andeffectivegroup,aswellasthephaseindexofaternaryonedimensionalplasmaphotoniccrystalforanobliquelyincidentelectromagneticwaveconsideringtheeffectofcollisionsinplasmalayers.Thedispersionrelationisderivedbyusingthetransfermatrixmethodandtheboundaryconditionsbasedonelectromagnetictheory.Thedispersioncurvesareplottedforboththenormalphotonicbandgapstructureandtheabsorptionphotonicbandgapstructure.Itisfoundthattheincreaseintheangleofincidenceshiftsthephotonicbandgaptowardhigherfrequencies.Also,thecutofffrequencyisindependentofcollisions.

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简介：Interactionbetweenhigh-intensitypulsedionbeam(HIPIB)andadouble-layertargetwithtitaniumfilmontopofaluminumsubstratewassimulated.Thetwo-dimensionalnonlinearthermalconductionequations,withthedepositedenergyinthetargettakenassourceterm,werederivedandsolvedbyfinitedifferentialmethod.Asaresult,thetwo-dimensionalspatialandtemporalevolutionprofilesoftemperaturewereobtainedforatitanium/aluminumdouble-layertargetirradiatedbyapulseofHIPIB.Theeffectsofionbeamcurrentdensityonthephasestateofthetargetmaterialsnearthefilmandsubstrateinterfacewereanalyzed.BothtitaniumandaluminumweremeltedneartheinterfaceaRerashotwhentheionbeamcurrentdensityfellintherangeof100A/cm~2to200A/cm~2.