281 research outputs found

    Functionalization Of Graphene And Reduced Graphene Oxide In Different Matrices

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    Graphene (G) presents a huge variety of intriguing properties, as extraordinary electronic transport characteristics. G, thanks to its low chemical reactivity, can also be used as an active support for catalytic nanoparticles. Some possible graphene application could be: its employment in active material in electronic devices such as sensors [1], batteries [2], supercapacitors, hydrogen storage systems or as fillers to produce multifunctional nanocomposite polymeric materials [3]. In more detail we would like to examine: different approach of reduction and functionalization of in situ reduced graphene oxide obtaining an enhancement of thermal conductivity and an resistivity decrease [4]. Surface modification and functionalization of rGO to improve its dispersion in organic solvent and also polymeric matrix [5]

    Influence of growing conditions on the reactivity of Ni supported graphene towards CO

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    Free standing graphene is chemically inert but, as recently demonstrated, CO chemisorption occurs at low crystal temperature on the single layer grown by ethene dehydrogenation on Ni(111). Such layer is inhomogeneous since different phases coexist, the relative abundance of which depends on the growth conditions. Here we show by X ray photoemission and high resolution electron energy loss spectroscopies that the attained CO coverage depends strongly on the relative weight of the different phases as well as on the concentration of carbon in the Ni subsurface region. Our data show that the chemical reactivity is hampered by the carbon content in the substrate. The correlation between the amount of adsorbed CO and the weight of the different graphene phases indicates that the top-fcc configuration is the most reactive

    Gamification en la búsqueda de galaxias

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    Desde hace algunos años, los juegos con fines científicos han ganado relevancia en el ámbito de la colaboración ciudadana en la ciencia, aplicándose en distintos campos y para distintas especialidades. Estos juegos científicos combinan dos conceptos interesantes desde la perspectiva de las ciencias informáticas: el Crowdsourcing (delegar tareas a una multitud de voluntarios) y la Ludificación (agregar aspectos lúdicos a actividades que no los tienen). En ese marco, nos propusimos desarrollar un juego que asista a investigadores del Nuevo Observatorio Virtual Argentino (NOVA) en la detección e identificación de galaxias en grandes imágenes del espacio. Nuestro objetivo fue involucrar a la sociedad en tareas relacionadas a la astronomía, y de esta manera, acercarla a la ciencia, mientras contribuímos con un aporte relevante como el mencionado anteriormente. El proceso de convertir una tarea en un juego masivo presentó un desafío importante, dada la cantidad de detalles y características que debían incluirse para fomentar el interés de la sociedad pero sin perder de vista la resolución del problema de fondo.Facultad de Informátic

    CO chemisorption at vacancies of supported graphene films: a candidate for a sensor?

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    We investigate CO adsorption at single vacancies of graphene supported on Ni(111) and polycrystalline Cu. The borders of the vacancies are chemically inert but, on the reactive Ni(111) substrate, CO intercalation occurs. Adsorbed CO dissociates at 380 K, leading to carbide formation and mending of the vacancies, thus preventing their effectiveness in sensor applications

    A full conformational characterization of antiandrogen cortexolone- 17α-propionate and related compounds through theoretical calculations and nuclear magnetic resonance spectroscopy

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    Cortexolone-17\u3b1-propionate is a topical antiandrogen under investigation for the treatment of androgen-related skin disorders. A full conformational characterization was realized, in comparison with other steroidal androgens and antiandrogens, by means of theoretical calculations at the B3LYP/6-31G(d) level supported by high-field NMR analyses. All of the studied molecules showed a good overlay; nevertheless, the different functional groups present in the skeleton of the molecules drive the individual biological profile. \ua9 2014 the Partner Organisations

    Domain wall dynamics and Barkhausen effect in metallic ferromagnetic materials. I. Theory

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    The Barkhausen effect (BE) in metallic ferromagnetic systems is theoretically investigated by a Langevin description of the stochastic motion of a domain wall in a randomly perturbed medium. BE statistical properties are calculated from approximate analytical solutions of the Fokker-Planck equation associated with the Langevin model, and from computer simulations of domain‐wall motion. It is predicted that the amplitude probability distribution P0(Φ) of the B flux rate Φ should obey the equation P0(Φ)∝Φ−1 exp(−Φ/〈Φ〉), with >0. This result implies scaling properties in the intermittent behavior of BE at low magnetization rates, which are described in terms of a fractal structure of fractal dimension D<1. Analytical expressions for the B power spectrum are also derived. Finally, the extension of the theory to the case where many domain walls participate in the magnetization process is discussed
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