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本帖最后由 细胞海洋 于 2012-10-26 13:45 编辑
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- H, b2 j$ c: Y0 vMany systems respond impulsively to slowly increasing external stresses. Normally smooth processes of stress release can be disrupted intermittently by large random events (or avalanches), such that a system undergoes abrupt structural changes. Using a combination of theory and experiment in a model system consisting of nickel microcrystals under compression, Stefanos Papanikolaou and colleagues investigate an intermediate regime in which the smooth background processes occur at similar rates to the external driving stresses, leading to the unusual observation of oscillatory behaviour in the fast avalanches themselves. This finding is, in principle, applicable to all intermittent phenomena with coexisting slow relaxations that compete to minimize the local internal stress. This description would include complex networks — such as the brain — during relaxation, disordered/jammed solids and earthquake faults, forcing a re-interpretation of experimental and simulation data. The cover shows a nickel microcrystal array with an overlay outline of the San Andreas Fault, where the forces observed in the microcrystals act on a larger scale. (Array by Dennis M. Dimiduk/ fault by D K Lynch/ USGS)5 P$ G9 m! a' L" Z+ \
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发表于 2012-10-26 13:26
