1,354,335 research outputs found

    Nonlinear dynamics induced in liquid crystals in the presence of the orbital and spin angular momentum of light

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    We studied the dynamical effects induced in a homeotropic nematic film when a normally incident circularly polarized light beam with an elliptical intensity profile is used. A three dimensional dynamical model shows that, besides the spin, the orbital angular momentum of photons also plays a role in the reorientation process. Our measurements fairly reproduce the main dynamical features predicted by the model in the near threshold region. The model, however, does not work, as it is, at higher incident laser power where chaotic director rotation was reported [A. Vella, A. Setaro, B. Piccirillo, E. Santamato, Phys. Rev. E 67, 051704 (2003)]

    Carbon incorporation in silicon-carbon films grown at different substrate temperatures

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    Hydrogenated microcrystalline silicon-carbon thin films have been deposited by plasma enhanced chemical vapour deposition technique at the substrate temperatures of 250 degrees C and 400 degrees C varying the radio frequency (RF) power in the 10- 100 W range. The effects of substrate temperature and RF power on the structural, compositional, optical, and electrical properties have been investigated. The increase of substrate temperature or RF power leads to a decrease of crystallinity degree and an enhancement of carbon content. Optical absorption in the UV-visible region and electrical conductivity are affected in a different way by the RF power and substrate temperature variations. Silicon grain nucleation of films deposited at the temperature of 250 degrees C on commercial doped tin oxide substrate has been explored, for different RF power, by means of X-ray diffraction measurements. (c) 2006 Elsevier B.V All rights reserved. RI Setaro, Antonio/D-1413-2010; Maddalena, Pasqualino/G-7114-201

    A passagem dos Setaro em Portugal: ópera depois do terramoto de 1755

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    A família Setaro foi uma das protagonistas da ópera em Portugal, no século XVIII. Sendo já conhecida a sua ligação ao Porto, este artigo revela os antecedentes dessa relação, a passagem de Nicola e Pietro Setaro por Lisboa, acompanhados de cantores e bailarinos italianos. Uma passagem atribulada e condicionada, que atesta a vontade de reorganização do espetáculo operático após o terramoto de 1755.info:eu-repo/semantics/publishedVersio

    A passagem dos Setaro em Portugal: ópera depois do terramoto de 1755

    No full text
    A família Setaro foi uma das protagonistas da ópera em Portugal, no século XVIII. Sendo já conhecida a sua ligação ao Porto, este artigo revela os antecedentes dessa relação, a passagem de Nicola e Pietro Setaro por Lisboa, acompanhados de cantores e bailarinos italianos. Uma passagem atribulada e condicionada, que atesta a vontade de reorganização do espetáculo operático após o terramoto de 1755.info:eu-repo/semantics/publishedVersio

    Nanoplasmonic colloidal suspensions for the enhancement of the luminescent emission from single-walled carbon nanotubes

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    Aiming to enhance the luminescence yield of carbon nanotubes, we introduce a new class of hybrid nanoplasmonic colloidal systems (π-hybrids). Nanotubes dispersed in gold nanorod colloidal suspensions yield hybrid structures exhibiting enhanced luminescence up to a factor of 20. The novelty of the proposed enhancement mechanism relies on including metal proximity effects in addition to its localized surface plasmons. This simple, robust and flexible technique enhances the luminescence of nanotubes with chiralities whose enhancement has never reported before, for example the (8,4) tube

    Marine diatoms as optical chemical sensors: A time-resolved study

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    Marine diatoms are microscopic algae living in aquatic environment; their skeleton, made of amorphous silica, possesses a complex geometrical structure that presents holes on different length scales in a fractal-like fashion, achieving a high surface-to-volume ratio and making them good candidates for gas detecting purposes. Indeed, different gas species can influence diatoms' photoluminescence emission according to their different polarizing abilities. In particular, to exploit marine diatoms as optical nitrogen dioxide sensors and in order to get a better insight on the nature of the photoluminescence quenching process induced by the gas molecules, continuous-wave and time-resolved photoluminescence studies have been carried out, showing that nitrogen dioxide affects only the photoluminescence yield without altering the dynamics of the recombination process. © 2007 Elsevier B.V. All rights reserved

    sPazzi sonori. L’archivio di Anna Maria Bruzzone come orecchio della memoria

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    The discovering of Anna Maria Bruzzone audio and written archive appears to be of a high magnitude because the digitization and cataloging of this archive are producing the first digital oral archive related to an Italian psychiatric hospital. The hospital was in the same buildings as the UNISI Department, where also the Historical Archive of the Arezzo psychiatric hospital is hosted. The archive consists of 36 tapes accompanied by the handwritten and the typewritten transcriptions of all the interviews. In addition to the complete transcriptions, different versions show all the work of editing A.M. Bruzzone made so that the interviews could be suitable for publication. The paper presents and discusses the lines of research stemming from a multidisciplinary research group, at the crossroads of digital humanities, oral history, and speech sciences
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