Electrochemical Phenomena
Mostrando 13-24 de 29 artigos, teses e dissertações.
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13. Study of organic light-emitting devices using rare earth and transition metals complexes. / Estudo de dispositivos orgânicos emissores de luz empregando complexos de terras raras e de metais de transição.
This work presents the study of the Rare Earth (RE) and Transition Metals (TM) complexes, as emissive layers of Organic Light-Emitting Devices (OLEDs) designed, built and electro-optically characterized. The thin films were thermally evaporated or spin-coated. This research started with the study of Europium complex changing its central ligand (CL), which sh
Publicado em: 2008
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14. Detecção amperométrica, com microeletrodos, de espécies reativas de oxigênio e nitrogênio em células isoladas estimuladas por substâncias biologicamente ativas. / Amperometric detection of reactive oxygen and nitrogen species in isolated cells, estimulated by biologically active organic compounds.
The production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is a metabolic situation, observed in different physiological conditions. When their production is exacerbated, there is an efficient antioxidant system able to control and re-install the homeostasis. Oxidative stress results from an acute and chronic imbalance between the pr
Publicado em: 2008
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15. Mecanismos reacionais e os processos de carga e descarga no caso de eletrodos planos de Pb em ácido sulfúrico e formação de eletrodos planos de PbO2 partindo de eletrodos de Pb
Two systems that form the basis of the lead-acid batteries were studied. The first system was the lead/sulfuric acid (Pb/H2SO4) interface. This interface is equivalent to negative electrode of lead acid batteries. The second system was the lead oxide/sulfuric acid (PbO2/H2SO4) interface. This interface is equivalente to the positive electrode of lead acid ba
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/10/2007
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16. Estudo comparativo da eficiência da difenilcarbazida e do óleo de coco saponificado microemulsionados na inibição da corrosão de aço carbono
The effectiveness of microemulsions (ME) of saponified coconut oil (OCS-ME) and diphenylcarbazide (DC-ME) on a carbon steel corrosion inhibition process was evaluated using an electrochemical method of polarization resistance. The ME was prepared with OCS, butanol, kerosene and saline solutions. OCS-ME and DC-ME showed highest inhibitions effects (77% and 92
Química Nova. Publicado em: 2007-10
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17. Estudo da eletrooxidação de monóxido de carbono em RuO2(110), e visualização morfológica e atômica de fases ricas em oxigênio na oxidação de Ru(0001) através da microscopia de varredura por tunelamento / Study of the electrooxidation of carbon monoxide on RuO2(110), and morphological and atomic visualization of oxygen-rich Ru(0001) surfaces by means of Scanning Tunneling Microscopy
In the last 30 years the parallel growth of the traditional Surface Science, under UHV environment, and Electrochemistry gave rise to a new interdisciplinary field: Surface Science and Electrochemistry. Techniques from both sciences give complementary information. Thus, in tandem, they are able to elucidate many atomic, structural and electronic phenomena, o
Publicado em: 2007
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18. Preparation of Pt, W e Os binary and tertiary alloys for the oxidation of methanol in low temperatures fuel cells / Preparação de ligas binárias e ternárias de Pt, W e Os para a oxidação de metanol em células a combustível de baixa temperatura
Modern society integrally depends on the production and consumption of energy for its activities like cooking, lighting and transportation and also for industrial processes. The increase in the demand for energy increases the levels of pollution, which has a direct negative effect in human health. Thus, it is imperative to search for new power sources which,
Publicado em: 2007
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19. INTERACTION BETWEEN LOW-RIPPLE SWITCHED CONVERTERS AND FUEL CEL LS / INTERAÇÃO ENTRE CONVERSORES CHAVEADOS COM BAIXA ONDULAÇÃO E CÉLULAS DE COMBUSTÍVEL
This dissertation discusses the interaction between fuel cells and the DC-DC converter just connected across its terminals. For that, it presents a modified algorithm to represent the dynamic behavior of fuel cell stacks as much the current ripple effects from power converters on such cells. PEM type fuel cells (Proton Exchange Membrane) are studied to get a
Publicado em: 2007
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20. Compatibility and thermal stability studies on plasticized PVC/PMMA blend polymer electrolytes complexed with different lithium salts
The lithium salt (x) (X= LiAsF6, LiPF6, LiN(C2F5SO2)2 , LiN(CF3SO2)2, LiBF4) was complexed with a host of poly(vinyl chloride) (PVC)/ poly(methyl methacrylate) (PMMA) blend polymer and plasticized with a combination of ethylene carbonate (EC) and propylene carbonate(PC). The polymer electrolyte films were prepared for constant PVC/PMMA blend ratio. The elect
Polímeros. Publicado em: 2005-03
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21. Degradação da resistência à corrosão de aços inoxidáveis duplex, devido ao envelhecimento em baixas temperaturas por tempos prolongados. / Degradation of the corrosion resistance of duplex stainless steel due to long aging at low temperatures.
Although duplex stainless steels exhibit good performance in many severe corrosive environments, their corrosion resistance can be hampered by precipitation of chromium (Cr) rich phases during aging heat treatments. Microstructural changes and corrosion behavior in two alloys with high and low content of chromium were investigated. Duplex stainless steels sa
Publicado em: 2004
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22. Aspectos relacionados à utilização da equação logística quadrática em processos eletroquímicos
The concepts of dissipation and feedback are contained in the behavior of many natural dynamical systems. They have been used to predict the evolution of populations leading to the formulation of the quadratic logistic equation (QLE). More recently, the QLE has been used to provide a better understanding of physicochemical systems with promising results. Man
Química Nova. Publicado em: 2002-02
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23. Corrosion and Electrochemical Oxidation of a Pyrite by Thiobacillus ferrooxidans
The oxidation of a pure pyrite by Thiobacillus ferrooxidans is not really a constant phenomenon; it must be considered to be more like a succession of different steps which need characterization. Electrochemical studies using a combination of a platinum electrode and a specific pyrite electrode (packed-ground-pyrite electrode) revealed four steps in the biol
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24. A synthetic peptide corresponding to the C-terminal 25 residues of phage MS2 coded lysis protein dissipates the protonmotive force in Escherichia coli membrane vesicles by generating hydrophilic pores.
The RNA phage MS2 encodes a protein, 75 amino acids long, that is necessary and sufficient for lysis of the host cell. DNA deletion analysis has shown that the lytic activity is confined to the C-terminal half of the protein. We have examined the effects of a synthetic peptide, covering the C-terminal 25 amino acids of the lysis protein, on the electrochemic