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简介:Forasyntheticapertureradar(SAR)systemmountedonageostationaryEarthorbit(GEO)satellite,thetrackcanbecurvilinear.Thus,abistaticSARsystembasedupongeostationarytransmitterand'receive-only'SARsystemonboardairplanes,namelyGEOspaceborne-airbornebistatic(GEOSA-BiSAR),issignificantlydifferentfromthetraditionalbistaticSAR.ThispapermainlystudiestheresolutioncharacteristicoftheslidingspotlightGEOSA-BiSARsystem.Firstly,thecommonazimuthcoverageandcoherentaccumulatedtimearetheoreticallyanalyzedindetail.Then,basedonthegradientmethod,theaccuratetwodimensionalresolutionofaGEOSA-BiSARsystemisanalyticallycalculated.Finally,thesimulationdatashowthecorrectnessandeffectivenessoftheproposedresolutionanalysismethod.
简介:WiththeconditionsofsmalldatasizeandlowSignal-to-NoiseRatio(SNR),theapplicationofHigherOrderStatistics(HOS)isrestrainednotonlybyitshighestimationvariance,butalsobyitslowestimationprecision.Therefore,amodifiedHOSbasedTimeDelayEstimation(TDE)algorithmisproposedtoovercometheseproblems.ComparingwiththeconventionalTDEalgorithms,theestimationvarianceisimprovedgreatly.Atypicalsimulationexampleiscompletedinordertotesttheperformanceofthealgorithmproposed,whichshowsthattheproposedalgorithmhasadvantagesoverthetraditionalonesinbothdetectionperformanceandcomputationefficiency.
简介:Theprincipleofthetwocarrierscontributingtocarrythepixelsignalchargesisfirstlypresented,andthenthebipolarjunctionphotogatetransistor(BJPT)withhighperformanceisproposedfortheCMOSimagesensor.Thenumericalanalyticalmodelofthephoto-chargetransferforthebipolarjunctionphotogateisestablishedindetail.Somenumericalsimulationsareobtainedunder0.6μmCMOSprocess,whichshowthatitsreadoutrateincreasesexponentiallywiththeincreaseofthephoto-chargeatappliedvoltage.
简介:ThetransmissionerrorcodeperformanceofsquareMQAMandstarMQAMmodulationschemesfortheAGWNRayleighfadingchannelisanalyzed.ThecorrespondingBERformulasandcomputeraidednumericresultsaregiven.ThereforeitprovidesatheoreticalbasisforchoosingMQAMmodulationschemesinmobilecommunications.
简介:Thispaperconsidersafrequency-divisionduplex(FDD)two-waychannelwithchannelestimationerror,wherechannelgainsareindependentofeachother.Itderivestheexactclosed-formoutageprobabilityexpressionsintheFDDsystemwithanalognetworkcoding(ANC)byuseofprobabilitytheory.Toprovidemoreinsights,anapproximatedversionfortheexactoutageprobabilityisalsodevelopedinthemedium-to-highsignal-to-noiseratio(SNR)region.ThesimulationresultsshowthatthederivedexactoutageprobabilitiesmatchtheresultsofMonteCarlosimulationsinallSNRregions,whiletheapproximatedoutageprobabilitiesalsoapproachthesimulationresultswhenthechannelconditionisgood.ItisinterestingthatANCintheFDDtwo-waychannelisprovedtooutperformthatofinthetime-divisionduplex(TDD)channelbythecomputersimulation.
简介:Thezero-voltagequasi-resonantboostswitchingDC-DCconverterhasbeeninves-tigatedbyusingthetimeaveragingequivalentcircuitapproachofperiodicallyswitchinglinearnetworks.TheDCsteadystateandACsmallsignalcharacteristicsoftheconverterarealsogiven.
简介:TheelectromagneticpropagationthroughaninhomogeneousmagnetizedplasmaslabisstudiedusingtheZ-transformformulationoftheFinite-DifferenceTime-Domain(FDTD)method.Thedirectionofelectromagneticpropagationisparalleltothebiasingmagneticfiled.TovalidatetheZ-transformalgorithm,thereflectionandtransmissioncoefficientsfortheright-handcircularlypolarizedwaveofthehomogeneousmagnetizedplasmaslabarecomputedbymeansofdiscreteFouriertransform.ThecomparisonbetweenthereflectionandtransmissioncoefficientsofthehomogeneousplasmaslabandanalyticalvaluesindicatesthatZ-transformalgorithmisveryaccurate.Whentheplasmafrequencyvariesaccordingtothesquarerootandparabolicrelations,thereflectionandtransmissioncoefficientsoftheinhomogeneousmagnetizedplasmaslabarecomputed.
简介:Themicroscopicmechanismoflowlevellaserirradiation(LLLI)mendingrheologyforbloodisanalyzedbythequantumtheory.Theresultsshowthatthelasercanresolvethefibrinclot,sothepropertyofbloodrheologyisimproved,andsomebondsofthecholesterolinbloodarefracturedbythelowlevellaser(LLL).Hencetheratioofmembranecholesteroltomembranephosphatideoftheredcellisreduced,andthenthebloodcirculationcanbeimproved.Theclinicalcuredtestsandsomecorrelativetestdatacanbeexplainedbythetheoreticalanalysesinthispaper.
简介:Anovelfibergratingvibrationdemodulationsystem,basedon2×2and3×3couplers,isdesigned.Basedonthephaseunwrappingalgorithm,thethree-wayasymmetricaloutputofthe3×3coupleranddemodulationstatecharacteristicsofthesystemwhenthevibrationsignalincludeshighharmonicwavesareanalyzedinsimulations.Theresultshowsthatwhenthethree-wayoutputisasymmetrical,themaximumdeviationofdemodulationsignalis1.625%,andwhenthevibrationsignalincludeshighharmonicwaves,themaximumdeviationofdemodulationsignalis0.9%.Thecorrespondingexperimentisconducted.Theexperimentalresultshowsthatthedynamicresolutionofthesystemis25.22nε/Hzwhenthevibrationpitchis5.5Hz.
简介:BasedontheanalysisofthespuriousintroducedbyphaseaccumulationtruncationwhichwasmadebyNicholas,anewsimplifiedalgorithmforspuriousspectruminthepresenceofphasetruncationispresentedbyusingthemappingmathematicsandnumbertheoreticmethod,itispossibletopreciselyanalyzethespuriouslocationandthespuriousamplitudeintroducedbyphasetruncationinpracticalapplicationsbycomputer.
简介:Thispaperpresentstheanalysisofopenmicrostripstructuresbyusingdiakopticmethodoflines(ML)combinedwithperiodicboundaryconditions(PBC).Theparametersofmicrostrippatchareobtainedfrompatchcurrentexcitedbyplanewave.ImpedancematrixelementsarecomputedbyusingfastFouriertransform(FFT),andreducedequationissolvedbyusingdiakoptictechnique.Consequently,thecomputingtimeisreducedsignificantly.TheconvergencepropertyofsimulatingopenstructurebyusingPBCandthecomparisonofthecomputertimebetweenusingPBCandusualabsorbingboundarycondition(ABC)showthevalidityofthemethodproposedinthispaper.Finally,theresonantfrequencyofamicrostrippatchiscomputed.Thenumericalresultsobtainedareingoodagreementwiththosepublished.
简介:WiththefastgrowthofChineseeconomic,moreandmorecapitalwillbeinvestedinenvironmentalprojects.Howtoselecttheenvironmentalinvestmentprojects(alternatives)forobtainingthebestenvironmentalqualityandeconomicbenefitsisanimportantproblemforthedecisionmakers.Thepurposeofthispaperistodevelopadecision-makingmodeltorankafinitenumberofalternativeswithseveralandsometimesconflictingcriteria.Amodelforrankingtheprojectsofmunicipalsewagetreatmentplantsisproposedbyusingexports'informationandthedataoftherealprojects.And,therankingresultisgivenbasedonthePROMETHEEmethod.Furthermore,bymeansoftheconceptoftheweightstabilityintervals(WSI),thesensitivityoftherankingresultstothesizeofcriteriavaluesandthechangeofweightsvalueofcriteriaarediscussed.Theresultshowsthatsomecriteria,suchas'proportionofbenefittoprojectcost',willinfluencetherankingresultofalternativesverystrongwhileothersnot.Theinfluencearenotonlyfromthevalueofcriterionbutalsofromthechangingtheweightofcriterion.So,somecriteriasuchas'proportionofbenefittoprojectcost'arekeycriteraforrankingtheprojects.Decisionmakersmustbecautioustothem.
简介:AsimulationmethodforthethermalanalysisofInAlAs/InGaAs/InPmid--infraredquantumcascadelasers(QCLs)basedonfinite--elementmethod(FEM)ispresented.ThethermaldistributionoftheQCLsonsubstrate--sideorepilayer--sidemountingformsissimulatedandtheresultsarecompared.Resultsshowthattheepilayer--sidemountingformhasmuchbetterheatdissipationcapabilitythanthesubstrate--sidemounting.