简介：作者为二个向后的随机的热方程联合的一些系统建立空可控制性。需要的可控制性结果借助于为控制系统的双系统证明合适的observability估计被获得。

简介：Awatt-classbackwardwaveoscillatorisproposed,usingtheconcisesinewaveguideslow-wavestructurecombinedwithapencilelectronbeamtooperateat220GHz.Firstly,thedispersioncurveofthesinewaveguideiscalculated,then,theoscillationfrequencyandoperatingvoltageofthedevicearepredictedandthecircuittransmissionlossiscalculated.Finally,theparticle-in-cellsimulationmethodisusedtoforecastitsradiationperformance.Theresultsshowthatthisnovelbackwardwaveoscillatorcanproduceover1-Wcontinuouswavepoweroutputinafrequencyrangefrom210GHzto230GHz.Therefore,itwillbeconsideredasaverypromisinghigh-powermillimeter-wavetoterahertz-waveradiationsource.

简介：Inthispaperweconsiderinfinitehorizonbackwarddoublystochasticdifferentialequations(BDSDEsforshort)coupledwithforwardstochasticdifferentialequations,whoseterminalfunctionsarenon-degenerate.ForsuchkindofBDSDEs,westudytheexistenceanduniquenessoftheirsolutionstakingvaluesinweightedL~p(dx)■L~2(dx)space(p≥2),andobtainthestationarypropertyforthesolutions.

简介：Combinedthedecompositionoftimereversaloperatorandthetimereversalre-verberationnulling,anewtimereversalprocessingapproachforecho-to-reverberationratioenhancementisproposed.Inthismethod,a2-dimensionalsignalsubspacefortherangeofthetargetandtwobottomfocusingweightvectorsfortherangesnearthetargetareobtainedbythedecompositionoftimereversaloperator.Fromthesignalsubspaceandfocusingweightvectors,aconstrainedoptimalexcitationweightvectorofsourcereceiverarraycanbededucedtonulltheacousticenergyonthecorrespondingbottomandmaximizetheenergyatthetar-get.Thismethodremediestheshortagesofconventionaltimereversalprocessing,timereversalreverberationnullingandtimereversalselectivefocusingmethod.Itfocusessoundenergyatthetargetandnullstheenergyatthebottomnearthetargetrangesimultaneously,thereforeenhancingtheecho-to-reverberationratiowithoutprobesourceandprior-knowledgeoftherel-ativescatteringintensityoftargetandbottom.Numericalsimulationsintypicalshallowwaterenvironmentsshowedtheeffectivenessoftheproposedmethodanditsimprovedperformanceforecho-reverberationenhancementthanconventionaltimereversalprocessing.

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简介：Thispaperproposesahybridmethodbasedontheforward-backwardmethod(FBM)andthereciprocitytheorem(RT)forevaluatingthescatteringfieldfromdielectricroughsurfacewitha2Dtargetaboveit.Here,theequivalentelectric/magneticcurrentdensitiesontheroughsurfaceaswellasthescatteringfieldfromitarenumericallycalculatedbyFBM,andthescatteredfieldfromtheisolatedtargetisobtainedutilizingthemethodofmoments(MOM).Meanwhile,therescatteredcouplinginteractionsbetweenthetargetandthesurfaceareevaluatedemployingthecombinationofFBMandRT.OurhybridmethodisfirstvalidatedbyavailableMOMresults.Then,thefunctionaldependencesofbistaticandmonostaticscatteringfromthetargetaboveroughsurfaceuponthetargetaltitude,incidentandscatteringanglesarenumericallysimulatedanddiscussed.Thisstudypresentsanumericaldescriptionforthescatteringmechanismassociatedwithrescatteredcouplinginteractionsbetweenatargetandanunderlyingrandomlyroughsurface.