简介:Theequationoftime-domainwavepropagationindispersivemediaandtheexplicitbeampropagationmethodarepresentedinthispaper.Thismethodisdemonstratedbytheshortopticalpulsesinadirectionalcouplerwithsecondorderdispersiveeffectandshowstobeinfullagreementwithformerreferences.Thismethodissimple,easyandpractical.
简介:Time-domainWavePropagationinDispersiveMedia①JUZhenle,FUJunmei,FENGEnxin(InstituteofMicrowaveEnginering&OpticalCommunicationTe...
简介:与缺点多层的分数维的领唱者的二新奇结构被介绍。光传播矩阵方法被用来计算发射度和反射。与一般领唱者相比多层,这些新奇结构有更宽的stopbands并且在更宽的stopbands的中间给超级狭窄的乐队看,它能被用作超级狭窄的通带过滤器。当在领唱者有一个嵌入的缺点时,通行证乐队能是1530nm的红外线的波长附近的不到0.6nm多层。在中央波长的光传播比99%高,它意味着一很低插入损失。如果有三层,三座超级狭窄的山峰能在stopband的中间被发现。中央波长是分别地1232.4nm,1372.8nm和1538.3nm。它比其它种狭窄的乐队过滤器好一些,它可以在光通讯被使用。CLC数字O482.3这个工作被国家科学基金支持(60577043),上海教育委员会(217608)的发展基础和上海领先的大学教师惩罚工程(T0102)。
简介:ThemethodtopumptheFBGwrittenintoanEr3+-dopedopticalfiberisproposedtoincreasethegroupvelocityofaprobingpulsebasedonthefactsthatpump-inducedprocesschangestherefractiveindexanddispersionassociatedwiththe4I15/2-4I13/2transitioninEr3+-dopedopticalfiber.Thesystemequationsarederived.Theeffectsofpumppoweranddopingconcentrationonthegroupvelocityarediscussed.
简介:Awide-anglebeampropagationalgorithmbasedonanobliquecoordinatesystemispresented.Awaveguidewithtiltedstructureissimulatedintermsofthismethodandtheconventionalwide-angleBPM.Bycomparingtheresults,itisfoundthatthismethodiseffectiveespeciallyintiltedstructure.TheY-junctionhasbeenalsosimulatedintermsofthisnewmethod,andthegoodresultsareobtained.
简介:1供应链管理当今全球已步人经济一体化和因特网新经济时代,市场的变化正在不断加快,需求的不确定性正在不断加大,势必要求信息交换快捷与准确,产品上市快速与及时.原来传统的企业管理模式--"纵向一体化"管理已不适应新时代的要求.
简介:Thepropagationoftwofemtosecondpulsesintheregionwithminimumgroup-velocitydispersion,influencedbythecrossphasemodulation(XPM)inphotoniccrystalfiber(PCF),isinvestigatedinthispaper.Theadaptivesplit-stepFouriermethodisusedtosimulatethegeneralizednonlinearSchrdingerequations(GNSE).ThenumericalresultsshowthatthecombinationoftheRamanscatteringandXPMcanmakethespectrumandthepulseshapechanged,inducingthepulsecompressionandsupercontinuumgeneration.TheRamaneffectfrommolecularvibrations,whichcanmakethepulsespectruminanomalous-dispersionregiontobemoresymmetrical,isalsodiscussed.
简介:Thespectraldensityofthequasi-homogeneous(QH)lighthasbeenknownwhenitscattersonQHmediaorpropagatesinfreespace.ThecasethatQHsourcesaresurroundedbyQHmediaisproposedinthispaper.Undertheparaxialapproximation,thespectraldensityoftheQHlightpropagatingthroughQHmediaisderived.AmodifiedscalinglawforthepropagationoftheQHlightthroughQHmediaisalsoobtained.Thislawalsoholdstrueinthefarfieldbeyondtheparaxialapproximation.
简介:TheelectromagneticpropagationthroughaninhomogeneousmagnetizedplasmaslabisstudiedusingtheZ-transformformulationoftheFinite-DifferenceTime-Domain(FDTD)method.Thedirectionofelectromagneticpropagationisparalleltothebiasingmagneticfiled.TovalidatetheZ-transformalgorithm,thereflectionandtransmissioncoefficientsfortheright-handcircularlypolarizedwaveofthehomogeneousmagnetizedplasmaslabarecomputedbymeansofdiscreteFouriertransform.ThecomparisonbetweenthereflectionandtransmissioncoefficientsofthehomogeneousplasmaslabandanalyticalvaluesindicatesthatZ-transformalgorithmisveryaccurate.Whentheplasmafrequencyvariesaccordingtothesquarerootandparabolicrelations,thereflectionandtransmissioncoefficientsoftheinhomogeneousmagnetizedplasmaslabarecomputed.
简介:CognitiveRadio(CR)systembasedonOrthogonalFrequencyDivisionMultipleAccess(OFDMA),suchasWirelessRegionalAreaNetworks(WRAN)andWorldwideInteroperabilityforMicrowaveAccess(WiMAX),oftenattempttoimproveperformanceviadynamicradioresourcemanagement,whichischaracterizedasconcurrentprocessingofdifferenttrafficandnondeterministicsystemcapacity.Itisessentialtodesignandevaluatesuchcomplexsystemusingpropermodelingandanalysistools.Inthepreviouswork,mostofthecommunicationsystemsweremodeledasMarkovChain(MC)andStochasticPetriNets(SPN),whichhavetheexplicitlimitationinevaluatingadaptiveOFDMACRsystemwithwideareatraffic.Inthispaper,wedevelopanexecutabletop-downhier-archicalColoredPetriNet(CPN)modelforadaptiveOFDMACRsystem,andanalyzeitsperformanceusingCPNtools.TheresultsdemonstratethattheCPNcanmodeldifferentradioresourcemanage-mentalgorithmsinCRSystems,andtheCPNtoolsrequirelesscomputationaleffortthanMarkovmodelusingMatlab,withitsflexibilityandadaptabilitytothetrafficswhicharrivalintervalandprocessingtimearenotexponentiallydistributed.
简介:Underthecomplicatedelectromagnetismcircumstance,themodelofdatafusioncontrolandguidanceofsurface-to-airmissileweaponsystemsisestablished.SuchwaysandtheoriesasElman-NN,radartrackingandfilter’sdatafusionnetbasedonthegroupmethodfordata-processing(GMRDF)areappliedtoconstructingthemodelofdatafusion.Thehighlyreliablestateestimationofthetrackingtargetsandtheimprovementinaccuracyofcontrolandguidanceareobtained.Thepurposeisoptimizationdesignofdatafusioncontrolandguidanceofsurface-to-airmissileweaponsystemsandimprovingthefightingeffectivenessofsurface-to-airmissileweaponsystems.
简介:Classicalnetworkreliabilityproblemsassumebothnetworksandcomponentshaveonlybinarystates,fullyworkingorfullyfailedstates.Butmanyactualnetworksaremulti-state,suchascommunicationnetworksandtransportationnetworks.Thenodesandarcsinthenetworksmaybeinintermediatestateswhicharenotfullyworkingeitherfullyfailed.Asimulationapproachforcomputingthetwo-terminalreliabilityofamulti-statenetworkisdescribed.Two-terminalreliabilityisdefinedastheprobabilitythatdunitsofdemandcanbesuppliedfromthesourcetosinknodesunderthetimethresholdT.Thecapacitiesofarcsmaybeinastochasticstatefollowinganydiscreteorcontinuousdistribution.Thetransmissiontimeofeacharcisalsonotafixednumberbutstochasticaccordingtoitscurrentcapacityanddemand.Tosolvethisproblem,acapacitatedstochasticcolouredPetrinetisproposedformodellingthesystembehaviour.Placesandtransitionsrespectivelystandforthenodesandarcsofanetwork.Capacitatedtransitionandself-modifiedtokencolourwithrouteinformationaredefinedtodescribethemulti-statenetwork.Bythesimulation,thetwo-terminalreliabilityandnodeimportancecanbeestimatedandtheoptimalroutewhosereliabilityishighestcanalsobegiven.Finally,twoexamplesofdifferentkindsofmultistatenetworksaregiven.