Stochastic Resonance in a Time-Delayed Mono-Stable System with Multiplicative and Additive Noise

The stochastic resonance （SR） in a time-delayed mono-stable system driven by multiplicative white noise, additive white noise, additive dichotomous noise as well as a periodic square-wave signal is considered from the view of the signal-to-noise ratio （SNR）. It is found that the SNR increases monotonically with the increase of the delay time. The SNR exhibits the SR behavior when it is plotted as a function of intensities of the noises, displaying the asymmetry of the dichotomous noise. The SNR varies non-monotonically with the increase of the system parameter and the amplitude of the input square-wave signal.     

用皮老虎作气源的简易气轨

几年来,我研制了一架用皮老虎作气源,用秒表计时的简易气轨。此气轨造价只有几十元,能进行运动学、动力学方面的多个实验。由于这种简易气轨不用电源,又很轻(不到一千克),所以可以拿到课堂上去做实验,特别适合农村中学用,也可以作学生实验仪器。商店出售的皮老虎要经过四处改装后才能作为简易气垫导轨和气垫弹簧振子的气源。