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Título:
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Nanoscopic Characteristics of Anhydrite (100) Growth
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Autores:
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Morales, Juan ;
Astilleros García-Monge, José Manuel ;
Fernández Díaz, Lurdes
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Tipo de documento:
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texto impreso
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Editorial:
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American Chemical Society, 2012
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Dimensiones:
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application/pdf
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Nota general:
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cc_by_nc_nd
info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Geología: Cristalografía
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Materia = Ciencias: Geología: Mineralogía
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Tipo = Artículo
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Resumen:
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The growth of anhydrite (100) surface in contact with supersaturated aqueous solutions (?anh = 1 -3.6) under low hydrothermal conditions (T = 60 -120 ºC) has been studied by use of a hydrothermal atomic force microscope (HAFM). Our observations show that growth on this surface occurs by lateral spreading ofmonomolecular layers (3.5 Å in height) and is highly anisotropic, with [001] and [001] alternating as fast and slow directions in successive monolayers. This anisotropic growth is evidence of strong structural control, which becomes less intense as temperature and/or supersaturation increases. The growth anisotropy affects the development of spirals, determining the combination of fast-moving and slow-moving steps to form bilayer steps around the emergence point of screw dislocations and leading to nonconstant spread rates. As a result, the overall efficiency of spiral growth mechanism is highly dependent on the interaction between slow-moving bilayers and fast-moving monolayers originating from different dislocations. Formation of two-dimensional nuclei occurs only at Tg>º80 ºCand ?anhg>2, two-dimensional nucleation density always being very low (
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En línea:
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https://eprints.ucm.es/id/eprint/57840/1/Astilleros.21.pdf
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