Narrow Results

The electron spin decoherence in endohedral fullerene A@C₆₀ is studied at low temperature using master equation under the Markov approximation. At lower magnetic field the polarization decay occurs with form e^-(t/T₁)2 consitent with previous reports having decays of the order of ℏ/A, and the relationship is satisfied. For the case of A@C₆₀ (A =N,P) endohedral fullerenes, the decay times on the order of tens of ns are calculated. For a strong external magnetic field, polarization strongly depends on the external magnetic field, the decay time is suppressed.

As a new type of seismic resisting device, the self-centering system is attractive due to its excellent re-centering capability, but research on such a system under random seismic loadings is quite limited. In this paper, the stochastic response of a single-degree-of-freedom (SDOF) self-centering system driven by a white noise process is investigated. For this purpose, the original self-centering system is first approximated by an auxiliary nonlinear system, in which the equivalent damping and stiffness coefficients related to the amplitude envelope of the response are determined by a harmonic balance procedure. Subsequently, by the method of stochastic averaging, the amplitude envelope of the response of the equivalent nonlinear stochastic system is approximated by a Markovian process. The associated Fokker–Plank–Kolmogorov (FPK) equation is used to derive the stationary probability density function (PDF) of the amplitude envelope in a closed form. The effects of energy dissipation coefficient and yield displacement on the response of system are examined using the stationary PDF solution. Moreover, Monte Carlo simulations (MCS) are used for ascertaining the accuracy of the analytical solutions.