Optic Spectroscopy
Mostrando 13-20 de 20 artigos, teses e dissertações.
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13. Use of two-dimensional correlation spectroscopy and construction and evaluation of a near-infrared spectropolarimeter / Uso da espectroscopia de correlação bidimensional (2D) e construção e avaliação de um espectropolarímetro para a região do infravermelho próximo (NIR)
The two-dimensional correlation spectroscopy was used in this work as a tool for spectral variable selection in the near-infrared (NIR) region aiming the determination of the following quality parameters of gasoline: ethanol content, MON (Motor Octane Number) and RON (Research Octane Number). To achieve this objective, it was developed a flow system to autom
Publicado em: 2006
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14. Determinação de parametros de qualidade da gasolina e estudo de contaminantes utilizando espectros do infravermelho proximo na fase vapor
A near infrared based on an acoustic optic tunable filter (AOTF) was constructed for spectra acquisition of gasoline in the vapor phase. The measuring system of the instrument was composed by a detection cell and a sample cell, where temperature sensors were adapted to monitor the temperature of the gasoline vapor and the temperature of the silicone bath use
Publicado em: 2005
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15. Caracterização e estudo das propriedades ópticas de íons de Neodímio em uma matriz vítrea à base de óxidos
O material hospedeiro, proposto nesta pesquisa, para os íons de Neodímio foi a matriz vítrea SNPZ (40SiO2 . 30Na2CO3 . 20PbO . 10ZnO (mol%)) dopada com XNd2O3 (%wt), onde X = 0,1; 0,3; 0,5; 0,7; 0,9; 1,1; 1,3; 1,5; 1,7; 1,9. Os espectros de absorção óptica da matriz vítreas SNPZ dopada com íons Nd3+ apresentaram bandas de absorção óptica (AO) cent
Publicado em: 2005
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16. Proposal for a modified fowler-milne method to determine the temperature profile in TIG welding at low currents
It is possible to assess the thermal efficiency of welding shielding gases by means of the arc temperature field analysis. Since this approach opens a remarkable study field to assess different shielding gases, giving support for dealing with advantages and disadvantages of commercial gas mixtures, there is a research line under development, which goal is to
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2004-03
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17. Fabricação e caracterização de vidros dopados com quantum dots de PbTe
In this work, we make a description and analysis of the fabrication method s of the PbTe quantum dots (QD) doped glasses and characterization techniques used by study the properties of the glasses. We have prepared glasses doped with 5 and 10 % of PbTe respectively. The characterization was by Scanning Electron Microscopy (SEM), High Resolution Transmission
Publicado em: 1998
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18. Studies in films of Poly(terephtalate of ethylene) re-covered with conducting Polyaniline. / Estudos em filmes de Poli (tereftalato de etileno) recoberto com polianilina condutora.
Composites with conductive properties have been proposed as materiais in which different physical properties of polymers are combined. In this work a composite consisting of surface layers of polyaniline, PANI, deposited on films of poly(ethylene terephtalate), PET, were prepared. In order to deposit the PANI the PET film were immersed in the solution in whi
Publicado em: 1998
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19. Sintese e caracterização do composito poli (3-metil-tiofeno)/borracha nitrilica
The electrochemical synthesis of a poly(3-methyl-thiophene)/nitrilic rubber composite was developed in this work. The effect of the synthesis conditions on the electrochemical properties of the composites was analyzed using cyclic voltammetry. Chronoamperometry was utilized to compare the redox behaviour of the composite films with that showed by pure poly(3
Publicado em: 1991
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20. Fluorescence microscopy with diffraction resolution barrier broken by stimulated emission
The diffraction barrier responsible for a finite focal spot size and limited resolution in far-field fluorescence microscopy has been fundamentally broken. This is accomplished by quenching excited organic molecules at the rim of the focal spot through stimulated emission. Along the optic axis, the spot size was reduced by up to 6 times beyond the diffractio
The National Academy of Sciences.