Molecular Relaxation
Mostrando 25-36 de 211 artigos, teses e dissertações.
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25. Influência de parâmetros moleculares em funções de correlação temporal na dinâmica de solvatação mecânica / Influence of molecular parameters on time correlations functions of mechanical solvation dynamics
No presente trabalho descrevemos nossos resultados relativos à investigação da dinâmica de solvatação mecânica por meio de simulações por dinâmica molecular, respeitando o regime da resposta linear, em sistemas-modelo de argônio líquido com um soluto monoatômico ou diatômico dissolvido. Estudamos sistematicamente a influência dos parâmetros m
Publicado em: 2007
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26. Acoplamento de dois feixes com lasers de femtossegundos em vapor de Rb
Femtosecond lasers operating in the mode-locked regime have a repetition rate determined by the round trip time of the pulse inside the laser cavity (TR = 2L/c). For Ti:sapphire lasers the repetition rate is typically of the order of 100 MHz, with TR 10 ns. Under this condition TR may be smaller then the population relaxation time (T1) and the coher
Publicado em: 2007
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27. Simulação dos processos de migração e relexação energética em sistemas orgânicos pi-conjugados emissores de luz / Simulation of energy migration and relaxation processes in organic pi-conjugated systems
Neste trabalho, o método de Monte Carlo é utilizado para simular o processo de difusão espectral da excitação em um sistema polimérico emissor de luz. A metodologia utilizada incorpora a relaxação energética intramolecular, a migração de energia incoerente entre segmentos conjugados e o processo final que pode ser radiativo (luminescência) ou nã
Publicado em: 2007
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28. Alloying in GeSi:Si (001) epitaxial nanocrystals / Formação de ligas em nanocristais epitaxiais de GeSi:Si (001)
The structural and electronic properties of nanoscale materials strongly depend on the chemical composition, as well as their size and shape. A big variety of morphologies can be achieved by controlling the experimental conditions during the epitaxial growth of Ge on a Si(001) substrate. In particular, three-dimensional islands with well defined size and sha
Publicado em: 2007
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29. Analysis of nuclear relaxation in granular systems
The longitudinal nuclear magnetic relaxation time, T1, of powdered samples was analyzed following the theory proposed by Browstein and Tarr to explain the T1 reduction of water confined in biological cells and the proposed by Rabbani and Edmonds where the molecular diffusion in liquids is substituted by spin diffusion to interpret the T1 behavior in solid pa
Brazilian Journal of Physics. Publicado em: 2006-03
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30. Correlation between luminescence polarization and molecular orientation in conjugated polymers / Correlação entre polarização da luminescência e orientação molecular em polímeros conjugados
The main goal of this work is the understanding of intermediated energy relaxation processes that are governed by Energy Transfer. Such processes strongly affect the optical properties of conjugated polymers, reducing the emission efficiency and the life time of OLEDs. We study specifically the polymer poly(p-phenylene vinylene), PPV, synthesized through the
Publicado em: 2006
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31. ROLE OF RENIN ANGIOTENSIN SYSTEM ON CARDIOVASCULAR CHANGES IN EXPERIMENTAL DIABETES: IN VIVO AND IN VITRO EVALUATION. / PAPEL DO SISTEMA RENINA ANGIOTENSINA NAS ALTERAÇÕES CARDIOVASCULARES DO DIABETES EXPERIMENTAL: AVALIAÇÕES IN VIVO E IN VITRO.
The aim of the present study was to elucidate the role of renin angiotensin system, by in vivo and in vitro evaluation, on cardiac dysfunction induced by streptozotocin experimental diabetes. Male Wistar rats (250-300g) were divided in 4 groups: control (n=9), control + Enalapril, (n=7, 1mg/Kg), diabetic (n=7, STZ, 50mg/Kg ev), and diabetic + Enalapril (n=7)
Publicado em: 2006
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32. 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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33. Secagem de caqui em condições controladas : efeito sobre a qualidade do produto e consumo energetico. / Drying of caqui in controlled conditions: effect on the product quality and energy consumption.
Aiming to understand the effect of drying conditions on the quality of dried persimmon as well as on the energetic consumption, this work investigated the viability of a process control strategy based on fixed temperature inside the product, which was compared with the conventional process that uses fixed air temperature. In order to evaluate the effect of a
Publicado em: 2005
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34. Study of hydrodynamic drag reduction polymericsolutions based on the drop impact images / Estudo do efeito da redução de atrito hidrodinamico em soluções polimericas nas estruturas produzidas pelo impacto de gotas
The presence of very small amounts (ppm) of high-molecular weight polymers in a solution produces high levels of drag reduction in a turbulent flow. This phenomenon, termed as the Toms Effect, was studied using images of the impact of a small drop against shallows liquid surfaces, both liquids containing a drag reducer agent. After the impact a crown and a c
Publicado em: 2004
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35. 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
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36. Fabricação de multicamadas de Quantum Dots de PbTe por laser ablation
This thesis was dedicated to the fabrication of thin films, quantum dots and multilayer ofIV-VI semi conducting materiaIs by pulsed-Iaser deposition (PLD). In the first part we report on the construction of a "home made" facility for pulsed laser deposition. The basic experimental set-up fabricated for PLD consists of a vacuum chamber pumped to a base pressu
Publicado em: 2004