简介:Thestationarycorrelationfunctionandtheassociatedrelaxationtimeforageneralsystemdrivenbycrosscorrelatedwhitenoisesarederived,byvirtueofaStratonovich-likeansatz.Theeffectsofcorrelatednoisesontherelaxationtimeofabistablekineticmodelcoupledtoanadditiveandamultiplicativewhitenoisesarestudied.ItisprovedthatforsmallfluctuationstherelaxationtimeTcasafunctionofλ(thecorrelatedintensitybetweennoises)exhibitsverydifferentbehavioursforαD(αandD,respectively,standfortheintensitiesofadditiveandmultiplicativenoises).Whenα>D,Tcincreaseswithincreasingλ.Butwhenα
简介:Waveguidesuperlattices,aspecialtypeofwaveguidearrays,canbedesignedtoachieveverylowcrosstalkatsubmicrometer/subwavelengthpitches.Thetheoreticalframeworkanddesignrationalesforsuchwaveguidesuperlatticeswillbepresentedindepth.Waveguidesidewallroughnesscanhelptodeterthecoherentcouplingbetweenidenticalwaveguidesinnearbysupercells,butitalsoinducesrandomfluctuationoftransmission.Statisticalbehaviorofthetransmissionduetoroughnessinawaveguidesuperlatticeissystematicallytreated.Complextransmissioncharacteristicsduetospectraloscillationandrandomroughnesswillbepresented,andtheirevolutionwiththesuperlatticelengthwillbeanalyzed.
简介:Experimentswereconductedtoinvestigatetheeffectofimpellergeometryandtongueshapeontheflowfieldofcrossflowfans.Threeimpellers(Ⅰ,Ⅱ,Ⅲ)havingsameouterdiameter,butdifferentradiusratioandbladeangleswereemployedfortheinvestigation.Eachimpellerwastestedwithtwotongueshapes.Flowsurveywascarriedoutforeachimpellerandtongueshapeattwoflowcoefficients.andforeachflowcoefficientatdifferentcircumferentialpositions.Theflowistwo-dimensionalalongthebladespanexceptneartheshrouds.Thetotalpressuredevelopedbytheimpellersineachcaseisfoundtobemaximumatacircumferentialpositionofaround270°.Thetotalandstaticpressuresattheinletofimpellersaremoreorlesssameregardlessofimpellerandtonguegeometry,buttheyvaryconsiderablyatexitoftheimpellers.ImpellerⅢwithtongueT2developshighertotalpressureandefficiencywhereasimpellerⅡwithtongueT2developsminimumtotalpressure.HigherdiffusionandsmallervortexsizearethereasonsforbetterperformanceofimpellerⅢwithtongueT2。
简介:Weproposeathree-partyschemeforquantuminformationsplitting(QIS)ofanarbitrarysingle-photonpolarizationstatebasedonweakcross-Kerrnonlinearitycombinedwithlinearopticselementssuchaspolarizationbeamsplitters(PBSs)andhalfwaveplates(HWPs).Theschemeisgeneralizedtothearbitrary-partycase.Withthehelpofquantumnondemolition(QND)measurements,ourschemescanbeaccomplishedinanalmostdeterministicway.Thetwoschemesarefeasiblewiththecurrenttechnology.
简介:Theadditivityruleforelectron-moleculescatteringisrevisedbyconsideringthedifferencebetweenthefreeatomandtheboundatominthemolecule.Thetotalcrosssectionsforelectronscatteringfromfluoromethanes(CF4,CF3H,CF2H2,andCFH3)arecalculatedinanenergyrangefrom100eVto1500eVbytherevisedadditivityrule.Thepresentcalculationsarecomparedwiththeoriginaladditivityruleresultsandtheavailableexperimentaldata.Betteragreementwitheachotherisobtained.
简介:Cryosurgeryisaneffectivewayofcuringmanydiseasesincludingtumorsandcancers.Itcanbeappliedusingavarietyofsystemsandcryogens.Cheap,convenient,reliableequipmentstillneedstobedevelopedsothatcryotherapymaybeacceptedbysurgeonsandhospitals.Thispaperpresentsacryosurgeryapparatusthatutilizesanauto-cascaderefrigerationsystem.RefrigerantmixtureR50/R23/R600awasselectedastheworkingfluid.Themixturecompositionwasalteredtoachievelowertemperaturesandhighercapacity.Thelowesttemperatureatthecryoprobecouldbeaslowas-100°C,and8Wrefrigerationcapacitycouldbeobtainedat-80°C.Aniceballof11.6mmdiametercouldbeformedwhenthecryoprobewasimmersedinawaterbathat37°C.
简介:DiamondfromLiaoning,Chinawasstudiedbysynchrotronradiationandinfraredspectrum.Thedistributionofdislocationsinthespecimenthasbeenrevealed.Anewmethodtodeterminetheorientationofcrystaldefectshasbeenproposedandtheorientationindexesofthedislocationsinthespecimenwerecalculatedbythismethod.Ithasbeenfoundthatthedislocationsinthespecimentarenearbutnotpreciselyparallelto{111}planes,Themaximumanglebetweendislocationand{111}planeisabout16°.AlmostallthedislocationsinthespecimenthavethesameBurgersvector1/2[101]andimplythesamenessoftheirorigination.
简介:Toestablishthemechanismofsurfacechangeinacontinuouspolishingsystem,anidealmathematicalmodelisbuiltbasedonWinkler’shypothesisandthePrestonequation.Thebasicfeaturesofthemodelarethechangeratesinthesurfacepeak–valley(PV)valuesoftheworkpiece,conditioningdiskandpitchlap,ratherthanthespecificsurfaceshapes.Inaddition,anequilibriumstateexistsinthesystem,indicatingthatthesurfacechangeratesareallzero.Underequilibrium,thesurfaceofthelapcouldremainflat,anditisinsensitivetothesurfaceerroroftheworkpiece.Thesecharacteristicslaythetheoreticalfoundationsforhigh-efficiencyandhigh-precisionpolishing.Themethodstoobtainanequilibriumstatewithflatsurfacesarethenproposedandconfirmedexperimentally.High-precisionsurfacesbetterthanλ/10(λ=632.8nm)areconsistentlyproducedexperimentally.
简介:Weproposethespectrumallocationandresourceschedulingalgorithmsincognitivepointtomultipoint(PMP)networkswithrapidchangesofspectrumopportunitiesandpresentamediaaccesscontrol(MAC)protocolbasedonthesealgorithms.Theobjectiveofspectrumallocationistomakeefficientuseofthespectrumwhilemaintainingthetransceiversynchronizationonfrequencyandtimeinthenetwork.Theobjectiveofresourceschedulingistoguaranteethequalityofservice(QoS)requirementsofdifferentkindsofconnectionsandtominimizethetotalenergyconsumptioninthenetworkaswell.Bysensingonlyasmallsetofpossiblechannelsineachslotbasedonthestatetransitionprobabilityofeachchannel,ourspectrumallocationalgorithmachieveshighspectrumefficiencyinthenetwork.Theresourceschedulingproblemisdividedintothreesubproblemsandwederiveoptimalsolutionstotheseproblemsbygreedyalgorithmandconvexoptimization.Thesimulationresultsshowthatouralgorithmcanmakeefficientuseofthespectrumandthenetworkresourcesatacostoflowcomputationalcomplexity.
简介:Fig.1showstheimpactparameter-averagedasymptoticvaluesofthenumberoftheemittedneutronsN_nandthenumberoftheemittedprotonsN_p(whenthevaluesofN_pandN_natt=200fm/cbecomenearlyconstants)i.e.b(topwindow)andb(bottomwindow)asafunctionofthebeamenergywithmomentumdependentintractionforthesystems~(76)Kr+~(40)Ca(leftwindows)and~(76)Kr+~(76)Kr(rightwindows)infivecases: