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Clustering of self-propelled particles : ウィキペディア英語版 | Clustering of self-propelled particles Many experimental realizations of self-propelled particles exhibit a strong tendency to aggregate and form clusters, whose dynamics are much richer than those of passive colloids. These aggregates of particles form for a variety of reasons, from chemical gradients to magnetic and ultrasonic fields. Self-propelled enzyme motors synthetic nanomotors also exhibit clustering effects in the form of chemotaxis. Chemotaxis is a form of collective motion of biological or non-biological particles toward a fuel source or away from a threat, as observed experimentally in enzyme diffusion and also synthetic chemotaxis or phototaxis. In addition to irreversible schooling, self-propelled particles also display reversible collective motion, such as predator-prey behavior and oscillatory clustering and dispersion. == Phenomenology == This clustering behaviour has been observed for self-propelled Janus particles, either platinum-coated gold particles〔 or carbon-coated sillica beads,〔 and magnetically or ultrasonically powered particles,〔〔 as well as for colloidal particles with an embedded hematite cube〔 and composed of slowly-diffusing metal ions,〔〔〔〔 and for enzyme molecule diffusion.〔〔 In all these experiments, the motion of particles takes place on a two-dimensional surface and clustering is seen for area fraction as low as 10%. For such low area fractions, the clusters have a finite mean size〔 while at larger area fractions, larger than 30%, a complete phase separation has been reported.〔 The dynamics of the finite-size clusters are very rich, exhibiting either crystalline order or amorphous packing. The finite size of the clusters comes from a balance between attachment of new particles to pre-existing clusters and breakdown of large clusters into smaller ones, which has led to the term of "living clusters".〔〔〔〔〔
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Clustering of self-propelled particles」の詳細全文を読む
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