منابع مشابه
Anomalous heat diffusion.
Consider anomalous energy spread in solid phases, i.e., <Δx(2)(t)>E≡∫(x-E)(2)ρE(x,t)dx∝t(β), as induced by a small initial excess energy perturbation distribution ρE(x,t=0) away from equilibrium. The second derivative of this variance of the nonequilibrium excess energy distribution is shown to rigorously obey the intriguing relation d(2)<Δx(2)(t)>E/dt2=2CJJ(t)/(kBT(2)c), where CJJ(t) equals...
متن کاملAnomalous Diffusion Tensor Imaging
Introduction The observation of non-monoexponential decay of diffusion-weighted MR signals with b-value has been widely reported [1]. Using the theory of anomalous diffusion, several groups have derived a stretched-exponential form for this signal decay (e.g. [2][3]) which parameterises the signal in terms of a distributed diffusivity α (measuring the overall rate of diffusion) and an anomalous...
متن کاملDisentangling sources of anomalous diffusion.
We show that some important properties of subdiffusion of unknown origin (including ones of mixed origins) can be easily assessed when finding the "fundamental moment" of the corresponding random process, i.e., the one which is additive in time. In subordinated processes, the index of the fundamental moment is inherited from the parent process and its time dependence from the leading one. In mo...
متن کاملAnomalous diffusion with absorbing boundary.
In a very long Gaussian polymer on time scales shorter than the maximal relaxation time, the mean squared distance traveled by a tagged monomer grows as approximately t(1/2) . We analyze such subdiffusive behavior in the presence of one or two absorbing boundaries and demonstrate the differences between this process and the subdiffusion described by the fractional Fokker-Planck equation. In par...
متن کاملAnomalous Diffusion: a Dynamic Perspective
This paper investigates whether spontaneous, stationary velocity fluctuations can lead to deviations from the regular Fickian diffusion. A kinematic analysis reveals that anomalous diffusion, both fast and slow, arises from long-tailed velocity auto-correlation functions (VACF). This infinite span of interdependence of the random velocity leads to the breakdown of the central limit theorem for ...
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ژورنال
عنوان ژورنال: Journal of the Chemical Society, Faraday Transactions 2
سال: 1973
ISSN: 0300-9238
DOI: 10.1039/f29736900330