33,600 research outputs found

    Ensaio de mini-espaçamento de Bracatinga (Mimosa scabrella Bentham) para a produção de madeira para fins energéticos.

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    bitstream/item/101181/1/PA-1983-Pereira-EnsaioMiniespacamento.pd

    Produção de madeira de Eucalyptus dunnii para fins energéticos procedências x mini-espaçamento.

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    bitstream/item/101187/1/PA-1983-Pereira-ProducaoMadeira.pd

    Resonant tunneling through protected quantum dots at phosphorene edges

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    We theoretically investigate phosphorene zigzag nanorribons as a platform for constriction engineering. In the presence of a constriction at the upper edge, quantum confinement of edge protected states reveals resonant tunnelling Breit-Wigner transmission peaks, if the upper edge is uncoupled to the lower edge. Coupling between edges in thin constrictions gives rise to Fano-like and anti-resonances in the transmission spectrum of the system.Comment: 8 pages,7 figure

    A influência do espaçamento e da idade de corte na produção de madeira de Eucalyptus grandis Hill ex Maiden.

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    A influência do espaçamento na produção de madeira de Pinus patula Cham. et. Schl.

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    bitstream/item/101184/1/PA-1983-Pereira-InfluenciaEspacamento.pd

    Influência do espaçamento na produção volumétrica e qualidade da madeira de Mimosa scabrella Benth. e Eucalyptus viminalis Labill.

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    bitstream/item/101160/1/PA-1983-Ahrens-InfluenciaEspacamentoProducao.pdf.pd

    All-sky Relative Opacity Mapping Using Night Time Panoramic Images

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    An all-sky cloud monitoring system that generates relative opacity maps over many of the world's premier astronomical observatories is described. Photometric measurements of numerous background stars are combined with simultaneous sky brightness measurements to differentiate thin clouds from sky glow sources such as air glow and zodiacal light. The system takes a continuous pipeline of all-sky images, and compares them to canonical images taken on other nights at the same sidereal time. Data interpolation then yields transmission maps covering almost the entire sky. An implementation of this system is currently operating through the Night Sky Live network of CONCAM3s located at Cerro Pachon (Chile), Mauna Kea (Hawaii), Haleakala (Hawaii), SALT (South Africa) and the Canary Islands (Northwestern Africa).Comment: Accepted for publication in PAS

    Magnetic states of linear defects in graphene monolayers: effects of strain and interaction

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    The combined effects of defect-defect interaction and of uniaxial or biaxial strains of up to 10\% on the development of magnetic states on the defect-core-localized quasi-one-dimensional electronic states generated by the so-called 558 linear extended defect in graphene monolayers are investigated by means of {\it ab initio} calculations. Results are analyzed on the basis of the heuristics of the Stoner criterion. We find that conditions for the emergence of magnetic states on the 558 defect can be tuned by uniaxial tensile parallel strains (along the defect direction) at both limits of isolated and interacting 558 defects. Parallel strains are shown to lead to two cooperative effects that favor the emergence of itinerant magnetism: enhancement of the DOS of the resonant defect states in the region of the Fermi level and tuning of the Fermi level to the maximum of the related DOS peak. A perpendicular strain is likewise shown to enhance the DOS of the defect states, but it also effects a detunig of the Fermi level that shifts away from the maximum of the DOS of the defect states, which inhibts the emergence of magnetic states. As a result, under biaxial strains the stabilization of a magnetic state depends on the relative magnitudes of the two components of strain.Comment: 9 pages 8 figure

    Propriedades da madeira de Taxodium distichum (L.) Rich.

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    bitstream/CNPF-2009-09/43373/1/Com_tec108.pd
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