Rayleigh Scattering
Mostrando 1-12 de 20 artigos, teses e dissertações.
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1. Spectrofluorimetric Determination of Hydrochlorothiazide by a Carbon Dots-Based Probe via Inner Filtering Effect and Resonance Rayleigh Scattering
Synthesis of carbon dots (CDs) from natural resources not only enables green synthesis and production of environmentally friendly materials, but also provides a cost-effective probe as a fluorescence nanosensor. The proposed sensor introduces a unique one-pot hydrothermal CDs synthesis from alfalfa leaves, which is promising for sensing hydrochlorothiazide (
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Tunneling effects in resonant acoustic scattering of an air bubble in unbounded water
Resumo O problema tratado neste trabalho é o espalhamento ressonante do som por uma bolha de ar imersa na água. O formalismo do espalhamento acústico em ondas parciais, relacionado ao problema proposto, é revisitado. Com base na analogia entre o espalhamento de partículas na mecânica quântica e o espalhamento acústico, os modos de vibração naturais
An. Acad. Bras. Ciênc.. Publicado em: 2016-06
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3. Aumento da taxa para um esquema de cooperação e probabilidade de erro para detector lâmbda -MRC em canal rayleigh / Data rate increase for cooperation scheme and error probability for the lâmbda -MRC detector under rayleigh channel
Neste trabalho, propomos um esquema novo baseado na diversidade por cooperação de usuários. Os resultados apresentados mostram que o novo esquema de cooperação consegue um aumento substancial da taxa de dados, mantendo a média da probabilidade de erro de bit perto dos valores obtidos no artigo User Cooperation Diversity-Part II escrito por Sendonaris e
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/05/2011
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4. Espalhamento de ondas eletromagnéticas por esferas e cilindros magnéticos: confinamento e transporte de ondas no limite de pequenas partículas e independência da energia armazenada com relação à forma do centro espalhador / Electromagnetic wave scattering by magnetic spheres and cylinders: waves confinement and transport in the small particle limit and independence of the stored energy with respect to the shape of the scatterer
O espalhamento eletromagnético por uma esfera com propriedades ópticas e raio arbitrários, conhecido como espalhamento de Lorenz-Mie, ou por um cilindro circular infinito, pode ser resolvido analiticamente e é comumente tratado dentro da abordagem de espalhadores dielétricos. Na região óptica, tanto meio circundante quanto partícula espalhadora possu
Publicado em: 2010
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5. Development and application of the pulse train hyper-Rayleigh scattering technique. / Desenvolvimento e aplicação da técnica de hiper Rayleigh com trem de pulsos
This thesis reports an extension of the Hyper-Rayleigh scattering technique (HRS) and its application to study the mechanisms that contribute to the molecular first hyperpolarizabilities (). We use a Nd:YAG laser, Q-switched and mode-locked, as pumping beam to excite the samples. The laser delivers 100 ps pulses modulated by a Q-switch envelope, and the outp
Publicado em: 2008
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6. CaracterizaÃÃo Ãptica de materiais nanoestruturados por tÃcnicas de geraÃÃo de segundo e terceiro harmÃnico
This work is dedicated to the optical characterization of nanostructured materials that are of interest for non-linear optics, optoelectronics and nanophotonics. The hyper- Rayleigh scattering (HRS) technique and the third harmonic generation (THG) technique were used. The materials investigated were a glass-ceramics containing sodium niobate (NaNbO3) nanocr
Publicado em: 2007
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7. Ab initio calculation of the (100) and (110) surface phonon dispersion of GaAs and GaN
In this work, we have calculated ab initio the phonon dynamics of the Ga-rich GaAs (100) (1 × 1), GaAs (100) (2 × 1), GaN (100) (1 × 1), GaAs (110) and GaN (110) surfaces. Our results for the (100) surfaces show that, while the (2 × 1) reconstruction is characterized by dimer vibrations, the (1 × 1) reconstruction presents interesting features which is
Brazilian Journal of Physics. Publicado em: 2004-06
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8. Efeitos nÃo lineares em lÃquidos orgÃnicos e meios nanoestruturados
In this thesis, we report studies of nonlinear transverse effects in organic liquids, carbon disulfide (CS2) and dimetil sulfoxide (DMSO), and of fluorescent emission effects in nanostructured media, more specifically, frequency upconversion in erbium doped barium titanate nanocrystals (BaTiO3:Er3+) and laserlike emission from inverted opal nanostructure of
Publicado em: 2004
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9. Study of nonlinear optics property of amino acid / Estudo de propriedades ópticas não lineares de aminoácidos
In this work we have studied nonlinear optical properties of amino acids using femtosecond laser pulses. The nonlinear index of refraction (nz) of L-alanine, L-proline, L-serine, L-threonine and L-arginine in aqueous solution have been determined. Also, the influence of pH in the magnitude of nz of amino acids in solution has been studied. Besides, we have d
Publicado em: 2003
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10. ARBITRARY CROSS SECTION WAVEGUIDES: ANALYSIS OF MODAL FIELDS AND OF DISCONTINUITIES BETWEEN ARBITRARY CROSS SECTION WAVEGUIDES / GUIAS DE ONDA DE SEÇÃO ARBITRÁRIA: ANÁLISE DE CAMPOS MODAIS E DE DESCONTINUIDADES EM GUIAS DE DIFERENTES SEÇÕES
In the present work, the modal fields and cutoff wavenumbers of arbitrary cross section waveguides are determined using the Rayleigh-Ritz method. Initially, the method is applied to waveguides with cross section approximated by a convex polygon. Polynomial basis functions are used. Such basis functions limit the number of modes that can be computed, since po
Publicado em: 2003
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11. Multichannel photomultiplier for multipass thomson scattering diagnostics
The application of a new multichannel 64 parallel amplification 10 stage photomultiplier arranged in 8 x 8 matrix of 20.32 mm x 20.32 mm, detector XP1752 from Philips, for laser light scattering diagnostics is now under development. Signal intensity calibration curve for eight parallel and individual channels, as well as cross talk between channels was measu
Brazilian Journal of Physics. Publicado em: 2002-03
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12. Nonlinear optical properties of aniline oligomers / Propriedades ópticas não-lineares de oligômeros de anilina
We report on the study of electronic optical non linearities in two aniline oligomers: dimer and the tetramer. Four tetramer concentrations were measured, pure and also 33 and 100% doped; one of dimer non doped another 100% doped. The solutions were prepared using dimethyl sulfoxide (DMSO) as solvent and the doping was performed with hydrochloric acid. The s
Publicado em: 2002