1000 resultados para thin domains
Resumo:
Dark brown sediment with sub-angular to rounded clasts. Contained areas of darker clay material. Contains rotation structures, mainly around rounded clasts. One side of the sample had significantly larger clasts than the other. Two different domains can be seen in this sample; a fine grained domain and a coarse grained domain.
Resumo:
Dark brown sediment with sub-angular to sub-rounded clasts. Rotation structures and lineations are common. Clasts ranging from small to large in size. Many large grains are fractured. Minor amounts of grain stacking and crushing can be seen. A few clay and organic rich domains can be seen.
Resumo:
Generally coarse grained, with a few different fine grained domains. Clasts range from small to large, ranging from sub-angular to sub-rounded in shape. Domain boundaries are clear, and the sample also contains rotation structures and lineations.
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Coarse grained sample with clasts ranging from small to medium. Clast shape ranges from angular to sub-angular. Lineations and rotation structures seen. Clay material and fine grained domains (darker colour) also seen.
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Dark brown sediment with clasts that range from small to large. The clast shape ranges from sub-angular to sub-rounded. Lineations are abundant in this sample. Edge-to-edge grain crushing can also be seen. Darker organic rich domains are also present throughout the sample.
Resumo:
This is a coarse grained sample with some very fine grained domains throughout the sample. The clast shape and size range from small to large, as well as angular to sub-rounded. Grain crushing is the most prevalent in this sample. It also contains some rotation structures and minor necking structures. Lineations and grain stacking can also be seen.
Resumo:
Two main domains can be seen in this sample. One is coarse grained with clasts ranging from small to medium in size. The other is very fine grained, and a very dark brown, potentially influenced by organic material. Grain crushing and lineations can be seen in the coarser domain.
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This sample contains two different domains; a coarse grained domain with well dispersed clasts, and a fine grained domain that potentially contains organics. The coarser grained domain contains comet structures, lineations and minor rotation without a central grain.
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Brown sediment with well dispersed clasts. Clasts range from small to medium in size and sub-angular to sub-rounded in shape. Alternating domains can be seen (light and dark). Darker domains appear organic rich. Lineations can also be seen throughout the sample.
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We investigate the ability of an applied electric field to convert the morphology of a diblock-copolymer thin film from a monolayer of spherical domains embedded in the matrix to cylindrical domains that penetrate through the matrix. As expected, the applied field increases the relative stability of cylindrical domains, while simultaneously reducing the energy barrier that impedes the transition to cylinders. The effectiveness of the field is enhanced by a large dielectric contrast between the two block-copolymer components, particularly when the low-dielectric contrast component forms the matrix. Furthermore, the energy barrier is minimized by selecting sphere-forming diblock copolymers that are as compositionally symmetric as possible. Our calculations, which are the most quantitatively reliable to date, are performed using a numerically precise spectral algorithm based on self-consistent-field theory supplemented with an exact treatment for linear dielectric materials.
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We investigate thin films of cylinder-forming diblock copolymer confined between electrically charged parallel plates, using self-consistent-field theory ( SCFT) combined with an exact treatment for linear dielectric materials. Our study focuses on the competition between the surface interactions, which tend to orient cylinder domains parallel to the plates, and the electric field, which favors a perpendicular orientation. The effect of the electric field on the relative stability of the competing morphologies is demonstrated with equilibrium phase diagrams, calculated with the aid of a weak-field approximation. As hoped, modest electric fields are shown to have a significant stabilizing effect on perpendicular cylinders, particularly for thicker films. Our improved SCFT-based treatment removes most of the approximations implemented by previous approaches, thereby managing to resolve outstanding qualitative inconsistencies among different approximation schemes.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Lanthanum-modified bismuth titanate, Bi4-xLaxTi3O12 (BLT), thin films with a La concentration of 0.75 was grown on Pt/Ti/SiO2/Si substrates by using the polymeric precursor solution and spin-coating method. The scanning electron microscopy (SEM) showed rounded grains, which is not typical for these system. The BLT films showed well-saturated polarization-electric field curve which 2P(r) = 41.4 muC/cm(2) and V-c = 0.99 V. The capacitance dependence on the voltage is strongly nonlinear, confirming the ferroelectric properties of the film resulting from the domains switching. These properties make BLT a promising material for FERAM applications.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Ferroelectric barium titanate thin films were produced by the polymeric precursor method. In this technique, the desired metal cations are chelated in a solution using a hydroxycarboxylic acid as the chelating agent. Barium carbonate and titanium IV isopropoxide were used as precursors for the citrate solution. Ethylene glycol and citric acid were used as polymerization/complexation agents for the process. The crystalline structure of the film annealed at 700 °C had a single perovskite phase with a tetragonal structure. The BaTiO3 film showed good P-E hysteresis loops and C-V characteristics due to the switched ferroelectric domains.