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Título: | Side-branch growth in two-dimensional dendrits. Part I: Experiments |
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Autor/a: | Couder, Yves; Maurer, J.; González Cinca, Ricard; Hernández Machado, Aurora |
Otros autores: | Universitat de Barcelona |
Abstract: | The dynamics of growth of dendrites’ side branches is investigated experimentally during the crystallization of solutions of ammonium bromide in a quasi-two-dimensional cell. Two regimes are observed. At small values of the Peclet number a self-affine fractal forms. In this regime it is known that the mean lateral front grows as t 0.5 . Here the length of each individual branch is shown to grow (before being screened off) with a power-law behavior t α n . The value of the exponent α n ( 0.5 ⩽ α n ⩽ 1 ) is determined from the start by the strength of the initial disturbance. Coarsening then takes place, when the branches of small α n are screened off by their neighbors. The corresponding decay of the growth of a weak branch is exponential and defined by its geometrical position relative to its dominant neighbors. These results show that the branch structure results from a deterministic growth of initially random disturbances. At large values of the Peclet number, the faster of the side branches escape and become independent dendrites. The global structure then covers a finite fraction of the two-dimensional space. The crossover between the two regimes and the spacing of these independent branches are characterized. |
Materia(s): | -Cristal·lografia -Estructura cristal·lina (Sòlids) -Solidificació -Experiments -Ciència dels materials -Crystallography -Layer structure (Solids) -Solidification -Materials science |
Derechos: | (c) The American Physical Society, 2005
http://dx.doi.org/10.1103/PhysRevE.71.031602 |
Tipo de documento: | Artículo Artículo - Versión publicada |
Editor: | The American Physical Society |
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