Nonlinear Optical Parameters
Mostrando 13-23 de 23 artigos, teses e dissertações.
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13. Análise do Efeito de Mistura de Quatro Ondas em Fibras Ópticas na Janela de 1550 nm / About the analysis of the Four Wave Mixing effect in optical fibers operating in the 1550 nm window
This work studies the characteristics of the Four Wave Mixing phenomenon in optical fibers operating in the 1550 nm window. The purpose is to understand theoretically the Four Wave Mixing phenomenon and confirm its effects through numerical simulations. Along this work, the dependence of the wave optical power generated by Four Wave Mixing process with fiber
Publicado em: 2003
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14. On the study of the nonlinear effects of both Self-Phase and Cross-Phase Modulation in optical fibers / Estudo dos Efeitos Não Lineares de Automodulação de Fase e Modulação de Fase Cruzada em Fibras Ópticas
In this work some phenomena that occur during the propagation of pulses of light in optical fibers [1], [7], [13], [16], [18], [20], [21], [22], [24], [25], [59] e [60] are studied. The study is based on the Nonlinear Schrödinger Equation (NLS), gotten in Chapter 2 from the equations of Maxwell, considering a nonlinear susceptibility. The adopted mathematic
Publicado em: 2003
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15. Analise do processo de extrusão na industria de "PET-FOOD" para a aplicação de tecnicas de controle avançado / Review of the extrusion industry in the "PET-FOOD" for the application of advanced techniques of control
The present study informs about the main features of extrusion control processes, based on product-wet density and moisture. To comprehend the study, some background of the classic control theory is provided. The process complexity, provided by formation of a bio-polymer from carbohydrate-lipid-protein raw materials, requires analysis using statistical conce
Publicado em: 2003
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16. Desenvolvimento de fontes laser, espectroscopia de alta resolução e resfriamento e aprisionamento magneto-optico de atomos de calcio
In this work, we report on an experimental system for laser cooling and magneto-optical trapping of calcium atoms, the development of the laser sources for this system, and a spectroscopic analysis of calcium transitions in hollow cathode electric discharges. In the case of calcium, the most efficient optical transition for the atom motion manipulation by ra
Publicado em: 2002
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17. Sintese e caracterização de preformas de silica-germania obtidas por deposição fase-vapor (VAD)
This research reports the study of deposition parameters of V AD (Vapor -phase Axial Deposition) silica-germanium and their correlation with structural properties. Characterization studies were conducted by small-angle X-ray scattering (SAXS), X-ray difftaction (XRD), scanning electronic microscopy (SEM), and X-ray fluorescence spectroscopy (XRF). The result
Publicado em: 2001
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18. Dynamic of optical nonlinearities in macromolecules and oligomers / Dinâmica de não linearidades ópticas em macromoléculas e oligômeros
This work reports the dynamic nonlinear optical properties of organic compounds, namely, ytterbium bis-phthalocyanine, furfuryl alcohol derivatives and azo-aromatic compounds. In order to carry out this investigation we developed an experimental extension to the standard Z-scan technique, named Z-scan with pulse trains. In this method, pulse trains contained
Publicado em: 2000
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19. DESENVOLVIMENTO E CARACTERIZAÇÃO DE DISPOSITIVOS FOTÔNICOS UTILIZANDO POLÍMEROS / DEVELOPMENT AND CHARACTERIZATION OF PHOTONIC DEVICES
Conjugated organic polymers are of wide interest as nonlinear optical materials because of their potential applications in photonic devices, such as communication devices. They have a large and fast nonlinear optical response, as well as a great flexibility in their preparing method. For device applications, the most important parameters are: third-order opt
Publicado em: 1996
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20. Modelo termodinamico para o aquecimento não-linear, a laser, e suas aplicações ao processamento de materiais
The subject of the computer modeling of the laser processing of materials continues to be highly topical in Materials Science. Basic to such an achievement was to have an well posed proposition to determine the time evolution of the temperature anywhere in the laser heated sample. Though models of such a kind abound in the literature, they are either rather
Publicado em: 1994
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21. Evolução temporal de excitações elementares em semicondutores fortemente fotoexcitados
We present a method that using a first principle theory allow us for the determination of nonlinear transport equations which describe irreversible processes in far from equilibrium systems. This method is applied to study the nonequilibrium thermodynamics and kinetics of evolution of relaxation processes in polar semiconductors under high levels of optical
Publicado em: 1982
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22. Sequence effects on the relative thermodynamic stabilities of B-Z junction-forming DNA oligomeric duplexes.
Circular dichroism (CD) and ultraviolet absorption techniques were employed in characterizing the sequence-dependent thermodynamic stabilities of B-Z junction-forming DNA duplexes. The Watson strand of the duplexes has the general sequence (5meC-G)4-NXYG-ACTG (where N = A or G and XY represents all permutations of pyrimidine bases). Duplexes were generated b
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23. The inhibition of rabbit skeletal muscle contraction by hydrogen ions and phosphate.
1. The effects of phosphate and protons on the mechanics and energetics of muscle contraction have been investigated using glycerinated rabbit psoas muscle. 2. Fibres were fully activated by addition of Ca2+ (pCa 4-5) at 10 degrees C. The velocities of contraction were measured in isotonic load clamps, and the velocities of unloaded fibres were measured by a