Direct Currents
Mostrando 1-12 de 204 artigos, teses e dissertações.
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1. APARATO ELETROQUÍMICO PARA SISTEMA DE AQUISIÇÃO DE DADOS MULTICANAL COM RESOLUÇÃO ESPAÇO-TEMPORAL
Spatiotemporal pattern formation in reaction-transport systems takes place spontaneously when the system is kept far from thermodynamic equilibrium. Targets, reaction fronts, waves, spirals, spots and stripes are some typical examples of selforganized structuring. In electrochemical systems, monitoring spatiotemporal patterns of potential in the solid/liquid
Quím. Nova. Publicado em: 2015-01
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2. Tradiciones electivas. Cambio, continuidad y ruptura en historia intelectual
Abstract This essay begins by questioning certain common places regarding such dichotomies as modernity vs. tradition, rupture vs. continuity, stereotypes still circulating among those historians who present a direct opposition between both poles, as if they were radically incompatible factors, mutually exclusive vectors. To this end, it emphasizes the dynam
Almanack. Publicado em: 2014-06
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3. Estragole blocks neuronal excitability by direct inhibition of Na+ channels
Estragole is a volatile terpenoid, which occurs naturally as a constituent of the essential oils of many plants. It has several pharmacological and biological activities. The objective of the present study was to investigate the mechanism of action of estragole on neuronal excitability. Intact and dissociated dorsal root ganglion neurons of rats were used to
Braz J Med Biol Res. Publicado em: 02/12/2013
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4. Da compra de produtos e serviços culturais ao direito de produzir cultura: análise de um paradigma emergente
Cultural activities are normally financed according to two classic paradigms: government funding and market financing. The former consists of direct state action or funding of civil society's cultural practices with state resources; the latter is anchored in the liberal or neoliberal tradition, the most recent expression of which involves the dominant curren
Dados. Publicado em: 2013-06
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5. Caracterização batimétrica e fisicooceanográfica do canal de acesso ao porto de Cabedelo/PB: uma análise ambiental ao derrame de óleo
The State of Paraíba is one of the most dynamic states of Brazil, strategically located in the northeast, is notable for the excellent potential for integration of different transportation modes forming the states of Rio Grande do Norte, Pernambuco and Alagoas. The dynamic that occurs with port activity causes changes in the space where it is installed. And
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/06/2011
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6. Analysis of electron direct tunneling current through very-thin gate oxides in MOS capacitors with the parallel-perpendicular kinetic energy components and anisotropic masses
An electron direct tunneling current model of n+- poly - Si/SiO2/p - Si(100) metal-oxide-semiconductor (MOS) capacitors has been developed by considering a parallel-perpendicular kinetic energy coupling, which is represented by the gate electron phase velocity, and anisotropic masses under a parabolic E-k dispersion relationship. The electron effective mass
Brazilian Journal of Physics. Publicado em: 2010-12
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7. Projeto de filtros para atenuação de correntes de modo comum e de sobretensões em acionamentos de motores elétricos utilizando inversores PWM
The use of inverters in most of electrical motor drives applications has been accompanie by several undesirable effects, such as overvoltage at the motor terminals, circulation of common mode currents and electromagnetic interference problems. The determining factors for most of these problems come with the high switching speed and frequency of the semicondu
Publicado em: 2010
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8. Generalized scalar modulation strategy for matrix converters / EstratÃgia de modulaÃÃo escalar generalizada para conversores matriciais
Power processors are devices capable to convert a set of voltages, with fixed amplitude and frequency, in other set, with controlled amplitude and frequency. The main function of these processors is to work as an adjustable power supply. The direct power converters are a class of power processors. They have significant advantages compared with the traditiona
Publicado em: 2008
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9. Controle vetorial de velocidade de um motor de indução trifásico com estimação neural de fluxo
This work describes the study and the implementation of the speed control for a three-phase induction motor of 1,1 kW and 4 poles using the neural rotor flux estimation. The vector speed control operates together with the winding currents controller of the stator phasis. The neural flux estimation applied to the vector speed controls has the objective of com
Publicado em: 2008
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10. Inrush current transients analysis in distribution feeders. / Análise das correntes transitórias de inrush em redes de distribuição.
The purpose of this dissertation is to analyze the inrush currents generated upon the energization of distribution system feeders. These said currents are relevant for typical designs in electric power concessionaries, for example upon calculating the ideal settings for protection devices. It was analyzed (or studies) 291 (two hundred and ninety one) oscilog
Publicado em: 2007
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11. Campos tensoriais de matÃria abelianos e nÃo-abelianos: geraÃÃo de massa e dualidade. / Abelian and non-abelian tensor matter fields: Mass generation and duality
In this Thesis we analyze the generation of mass to the antisymmetric tensor matter field in a non-Abelian model and the mapping of the antisymmetric matter field to the antisymmetric tensor gauge field in the Abelian case. For the mass generation, we use two different mechanisms. The first one is the spontaneous symmetry breaking, where we use scalar fields
Publicado em: 2007
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12. Estudo voltamétrico da interação dos íons Zn2+, Cu2+, Cd2+ e Pb2+ com a enzima catalase
Catalase (CAT), which is an important enzyme that catalyzes the decomposition of hydrogen peroxide (H O ) to water (H O) and oxygen (O ), contains 2 2 2 2 some metal binding sites (Cys, His). The binding of metal ions to CAT can change or stabilize its secondary structure, resulting in its inhibition or activation, respectively. The inhibition of CAT, which
Publicado em: 2007