弱信號驅(qū)動的延遲雙穩(wěn)系統(tǒng)的隨機共振.pdf

1、蘭州大學(xué)碩士學(xué)位論文弱信號驅(qū)動的延遲雙穩(wěn)系統(tǒng)的隨機共振姓名：邵瑞華申請學(xué)位級別：碩士專業(yè)：物理學(xué)理論物理指導(dǎo)教師：陳勇20090501ABSTRACTAnysysteminvolvingafeedbackcontrolwillalmostcertainlyinvolvetimedelays，becauseafinitetimeisrequiredtosenseinformationandthenreacttoitIngeneral，de

2、layisconsideredasareactionchainora(en—ergyorsigna)transportprocessinmanysystemsThemodelinvolvingdelays，whichcanbedescribedmathematicallybydelaydifferentialequations(DDEs)，ismorerealisticandwillreportthephysicalworldmorea

3、ccuratelyManynewphenomenaareinducedbythedelaysuchasexcitation，oscillation，instabilitychaos，Hopebifurcation，synchronization，andSOonInnumericalstudiesOffdelayproblems，EulerandRungeKuttamethodsareusuallyusedAnalyticalresult

4、sofDDEsarequitedifficulttoobtained，However，thestabilityanalysisandsmalldelayapproximationmethodscanresolvetheproblemsbetterInthisarticle，weintroducedtherolesofdelaysinavarietysystems，explainedthemethodswereusingtodealwit

5、hdelayandstochasticresonanceproblems，thentheequivalentLangevinequationfromthedelayedstochasticbistablesystemWascalculated，andtheoutputpowerspectrumandthesignaltonoiseratio(SNR)ofthesystemdrivenbyaweaksignalwereobtained，b

6、asedontheseresults，wediscussedtheinfluencesofdelayonstochasticresonance(SR)indetail‘Thereisadelayfeedbackinourmodel，whichcaneffectSRbyrood—ulatingthesystemstatesTheSRphenomenonisobservedmoreeasilywhenthefeedbackisnegativ

7、e，butitisalsoeasilyinterferedbydelayThemaximumofoutputSNRwillbedecreasedwiththeincreasingofdelaywhichmeansthetimedelaywillsuppresstheSRphenomenonfortheneg—ativefeedbackOnthecontrarywhenthefeedbackispositive，delaycanimpro