Dispersive Media
Mostrando 13-21 de 21 artigos, teses e dissertações.
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13. Influencia do meio e tempo de armazenamento na resistencia a microtração de sistemas adesivos / Influence of time and storage medium in the microtensile bond strength of adhesive systems
The purpose of this study was to evaluate "in vitro" the microtensile bond strength of two adhesive systems applied to the dentin as a function of time and storage medium, as well as to illustrate, through Scanning Electron Microscope (SEM) images, the nanoleakage of the hybrid layer, which had its constituents evaluated by microanalysis (EDS). Eighty recent
Publicado em: 2008
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14. Informação, velocidade da luz e pontos não analíticos / Information, light velocity and non-analytical points
O trabalho inicia com uma revisão sobre o conceito de velocidade de grupo e de fase, e uma breve discussão do que ocorre quando um pulso se propaga num meio dispersivo. Em seguida, fazemos um estudo da equação de onda de Helmholtz, seguido por uma descrição do modelo de Drude-Lorentz para a susceptibilidade elétrica. Durante este estudo exploramos as
Publicado em: 2007
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15. "Synthesis and characterization of polyaniline mixed in different polymeric matrices for protection against corrosion of metallic alloys" / "Síntese e caracterização da mistura de polianilina em diferentes matrizes poliméricas para proteção contra a corrosão de ligas metálicas"
In this work, polyaniline (PAni) blends and composites were obtained on platinum (Pt) and stainless steel (AISI-304) substrates. The effects of chemical and electrochemical syntheses were studied in different aqueous media. PAni blends and composites were prepared from aniline monomer-containing solutions of H3PO, that contained different concentrations of s
Publicado em: 2006
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16. Condutividade e movimento de carga espacial em amostras desordenadas / Conductivity and charge displacement in disordered samples
Dispersive conductive process are characterized by non-exponential residence times of the hopping carrier. As a consequence, hereditary effects appear and the problem must be conducted in the Laplace space. A bunch of known dielectric distributions functions and others were used as possible functions describing the disordered medium. A careful study of their
Publicado em: 2000
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17. Soluções superluminais equações de onda relativisticas e a relatividade especial
In the last years, two types of superluminal wave motion have been predicted theoretically and verified experimentally: (i) superluminal group velocities, observed in the propagation of electromagnetic waves in dispersive media, in the tunneling of electrons and microwaves and in the propagation of microwaves in the air; (ii) superluminal motion of finite en
Publicado em: 1999
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18. Avaliação das propriedades pre-concetradoras de metais das silicas modificadas para analise por fluorescencia de raios-X
Batch-wise liquid-solid extraction using chemically modified silica was studied as a pre-concentration method for non-essential heavy-metals, such as cadmium, lead and mercury, for subsequent analysis by Energy Dispersive X-Ray Fluorescence (EDXRF). Silicas modified with zirconium phosphate (SiZrP - 0.27 mmol g of phosphate) and/or propyl imidazol (Silm - 0.
Publicado em: 1997
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19. Iron Bacteria in Drinking-Water Distribution Systems: Elemental Analysis of Gallionella Stalks, Using X-Ray Energy-Dispersive Microanalysis
“Iron” bacteria belonging to the genus Gallionella were observed by scanning electron microscopy in water samples and attached to pipe surfaces in a Southern California drinking-water distribution system. The cells were recognized by their characteristic elongated helical stalks composed of numerous intertwined microfibrils. Many of the stalks were parti
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20. Nanobacteria: An alternative mechanism for pathogenic intra- and extracellular calcification and stone formation
Calcium phosphate is deposited in many diseases, but formation mechanisms remain speculative. Nanobacteria are the smallest cell-walled bacteria, only recently discovered in human and cow blood and commercial cell culture serum. In this study, we identified with energy-dispersive x-ray microanalysis and chemical analysis that all growth phases of nanobacteri
The National Academy of Sciences.
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21. Isolation, Cultural Maintenance, and Taxonomy of a Sheath-Forming Strain of Leptothrix discophora and Characterization of Manganese-Oxidizing Activity Associated with the Sheath
Leptothrix discophora SP-6 was isolated from the outflow reservoir of an artificial iron seep. Its sheathforming phenotype was maintained by slow growth in a mineral salts-vitamin-pyruvate medium under minimal aeration at 20 to 25°C. A sheathless variant, SP-6(sl), was isolated from smooth colonies that appeared on spread plates after rapid growth of SP-6 i