983 resultados para Roques volcàniques -- Catalunya -- Alt Empordà
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A novel conjugated oligomer, oligo(9,9'-dioctylfluorene-alt-bithiophene) (OF8T2), was found to exhibit a unique phase transition between crystalline and liquid-crystalline states, and a liquid-crystalline glass was easily generated, offering better TFT device performance. In thin films, upon annealing the OF8T2 molecules oriented preferentially with their planes of conjugation being normal to the substrate, and both film thickness and annealing temperature were critical to the film morphology and the molecular orientation. When the OF8T2 film was deposited on a rubbed polyimide surface and annealed, the molecules aligned their long axes along the rubbing direction.
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A series of donor-acceptor low-bandgap conjugated polymers, i.e., PTnBT (n = 2-6), composed of alternating oligothiophene (OTh) and 2,1,3-benzothiadiazole (BT) units were synthesized by Stille cross-coupling polymerization. The number of thiophene rings in OTh units, that is n, was tuned from 2 to 6. All these polymers display two absorption bands in both solutions and films with absorption maxima depending on n. From solution to film, absorption spectra of the polymers exhibit a noticeable red shift. Both high- and low-energy absorption bands or P'F5BT and PT6BT films locate in the visible region, which are at 468 and 662 nm for PT5BT and 494 and 657 nm for PT6BT.
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Monodisperse oligo[(1,4-phenyleneethynylene)-alt-(2,5-thiopheneethynylene)]s, new candidates for molecular wires, were rapidly synthesized via an iterative divergent/convergent doubling strategy in solution as well as on Merrifield's resin.
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A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification in order to obtain a completely soluble product. The synthesis process was traced through by LR. Compared with the model compounds, the presumed structure of this comblike polymer has been proved to be valid by C-13 NMR The comb polymer is a white rubbery solid. It can be dissolved in butanone and THF, and manifests good film forming ability.
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Este artículo resulta de investigaciones en torno al “enverdecimiento” de las ciudades y las oportunidades de la agricultura urbana para la alimentación de una población en constante aumento que no trabaja la tierra. También es fruto de actividades de mejora de ambientes urbanos realizadas con la Escuela de Ingenieros Agrónomos de la Universidad Politécnica de Madrid. A través de casos de agricultura urbana, entendiendo por ella el conjunto de prácticas para la producción de alimentos y plantas ornamentales dentro de las ciudades y en sus entornos, se analizan alternativas para la recuperación de espacios construidos e incremento de la calidad de vida de la población. Todo ello se traduce, además, en creación de riqueza y mejora del paisaje urbano, siempre desde criterios de sostenibilidad que favorecen el desarrollo local desde la Cumbre de la Tierra de Río de 1992 y la Conferencia sobre Desarrollo Sostenible Río+20 de 2013.
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Màster Oficial en Estudis Avançats en Història de l'Art. Curs: 2008-2009. Directora: Imma Socias
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Màster Oficial en Gestió del Patrimoni Cultural
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Aquesta memòria és un estudi sobre l’avaluació ambiental del nitrogen a Catalunya, tot analitzant l’evolució que aquest element tant important ha tingut des del 1997 al 2003 en el nostre país