Nonlinear Spectroscopy
Mostrando 25-36 de 61 artigos, teses e dissertações.
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25. Absorção de multi-fótons em polímeros e resinas poliméricas: espectroscopia não linear e microfabricação / Multi-photon absorption in polymers and polymeric resins: nonlinear spectroscopy and microfabrication
Nesta tese, estudamos o processo de absorção multifotônica em polímeros e resinas poliméricas, abordando tanto aspectos fundamentais quanto aplicados. Com relação aos aspectos fundamentais, estudamos processos de absorção multifotônica (absorção de dois, três e quatro fótons) no polímero conjugado MEH-PPV (poly(2-methoxy-5-(2´-ethylhexyloxy)-
Publicado em: 2009
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26. SÃntese e caracterizaÃÃo de nanopartÃculas de nÃquel para Ãptica nÃo linear / SÃntese e caracterizaÃÃo de nanopartÃculas de nÃquel para Ãptica nÃo linear
In this work, we describe the synthesis of nickel nanoparticles (NPs) stabilized using poly (vinyl pyrrolidone), their structural and optical (linear and nonlinear) characterization. In Chapter 1 we present a general introduction describing the work performed. In Chapter 2 it is presented a review of nickel NPsâ properties and some synthesis processes. In C
Publicado em: 2008
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27. Dinâmica oscilatória na eletrooxidação de etileno glicol / Oscillatory dynamics in the ethylene glycol electrooxidation reaction
In the present work were studied some nonlinear aspects of the catalytic oxidation of ethylene glycol (EG) on platinum electrodes in alkaline media (KOH). The systems dynamics was investigated by means of cyclic voltammetry, current and potential time series, and electrochemical impedance spectroscopy (EIS). The EIS results reveal the presence of a hidden ne
Publicado em: 2008
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28. Photomultiplier nonlinear response in time-domain laser-induced luminescence spectroscopy
A new procedure to find the limiting range of the photomultiplier linear response of a low-cost, digital oscilloscope-based time-resolved laser-induced luminescence spectrometer (TRLS), is presented. A systematic investigation on the instrument response function with different signal input terminations, and the relationship between the luminescence intensity
Química Nova. Publicado em: 2007-02
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29. Vibrational spectroscopy of self-assembled polyelectrolytes films by sum-frequency generation / Espectroscopia vibracional de filmes automontados de polieletrólitos através da geração de soma de frequências
In this work, Sum-Frequency Vibrational Spectroscopy, a nonlinear optical technique that is sensitive to molecular conformation at interfaces and surfaces, was used to characterize the molecular ordering of self-assembled films during all steps of self-assembly, having as model poly(allylamine hydrochloride) (PAH) / poly(styrene sulfonate) (PSS) polyelectrol
Publicado em: 2007
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30. Comparison between Least-Square support vector machines and linear methods for calibration transfer / Comparação entre maquinas de vetores de suporte por minimos quadrados (LS-SVM) e metodos lineares para transferencia de calibração
The aim of this work was to compare the linear methods of calibration Partial Least Squares (PLS) and Piece-wise Direct Standardization (PDS) and a nonlinear method Least-Squares Support Vector Machines (LS-SVM) on calibration transfer to multivariate calibration models to the determination of alcoholic grade in cachaça in five different tempera
Publicado em: 2007
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31. Center metallic effect on intermolecular interactions of complexes [M(CN)5NO]x- with poly(ethylene oxide) in aqueous two-phase systems / Efeito do centro metálico nas interações intermoleculares dos complexos [M(CN)5NO]x- com o poli(óxido de etileno) em sistemas aquosos bifásicos
In this thesis has been studied the metallic center influences of pentacianonitrosylmetalates, [M(CN)5NO]x-, on the partition coefficient (K), of these complex anions in aqueous two-phase systems (ATPS). The ATPS were obtained by mixing stock aqueous solutions of an inorganic salt (Li2SO4 or Na2SO4) with a stock solution of poly(ethylene oxide) of average mo
Publicado em: 2007
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32. Microstructural evaluation of rare-earth-zinc oxide-based varistor ceramics
Zinc oxide varistors are nonlinear voltage dependent ceramic resistors used to suppress and limit transient voltage surges. The work reported in this paper involves the relationship between microstructural characteristics and the varistor performance of ZnO ceramics doped with rare-earth oxides. Samples of these ceramics with different nonlinear current-volt
Materials Research. Publicado em: 2005-12
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33. Relaxação em sistemas moleculares complexos / Relaxation in complex molecular systems
In this Thesis are presented studies by Molecular Dynamics simulations on some molecular systems presenting complex dynamics behavior (i.e., relaxation process caracterized by multiple time scales), including saccharides aqueous solutions, double helix DNA systems, air/water interfaces containing surfactants, and supercooled water. These systems, although cl
Publicado em: 2005
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34. Acoplamento eletrÃnico atravÃs das ligaÃÃes em derivados do 2,2-paraciclofano
Foram calculados os elementos de matriz de acoplamento eletrÃnico entre sÃtios doadores e aceitadores de elÃtrons em compostos derivados do 2,2-paraciclofano. Estes elementos de matriz, tambÃm chamados de interaÃÃo efetiva entre os referidos sÃtios, de acordo com a teoria das transferÃncias de elÃtrons sÃo proporcionais à intensidade da transiÃÃ
Publicado em: 2005
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35. Desenvolvimento de fontes de radiação coerente na região azul com lasers semicondutores para experimentos de resfriamento e aprisionamento de atomos de calcio / Development sources of coherent radiation in the blue region with semiconductors laser for experiments of coolong and trapping of neutral calcium atoms
Esta tese apresenta o desenvolvimento de fontes de radiação coerente na região do azul baseadas em lasers semicondutores para excitar a transição de resfriamento e aprisionamento 1 S0-1P1 do Cálcio, em 423nm. Foi construído um laser de diodo em cavidade estendida emitindo em g =846 nm que foi empregado em uma configuração de Cavidade Estendida de Li
Publicado em: 2004
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36. SÃntese e caracterizaÃÃo de novos derivados mesoiÃnicos para aplicaÃÃo de Ãptica nÃo-linear e atividade biolÃgica
Mesoionic compounds constitute a group of heterocyclic betaines stabilized by delocalisation of electrons and charge, the synthesis of which has proven of great interest. This stemmed from (a) their wide range of biological activity with a considerable possibility of obtaining pharmaceuticals; (b) their special physical properties for non-linear optics appli
Publicado em: 2004