Metallic Bonds
Mostrando 1-12 de 18 artigos, teses e dissertações.
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1. APRESENTAÇÃO - História Antiga: Diferentes Perspectivas
Biodiesel is a suitable alternative to replace the petro-diesel. The biodiesel is formed by unsaturated esters easily degraded by interferences of oxygen, temperature, contact with metals or contaminants. The aim of this research was to investigate the biodiesel degradation process via 1H nuclear magnetic resonance (NMR) spectroscopy, observing the olefinic,
Rev. Bras. Hist.. Publicado em: 2020-08
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2. Evaluation of the Oxidation Degradation Process of Biodiesel via 1H NMR Spectroscopy
Biodiesel is a suitable alternative to replace the petro-diesel. The biodiesel is formed by unsaturated esters easily degraded by interferences of oxygen, temperature, contact with metals or contaminants. The aim of this research was to investigate the biodiesel degradation process via 1H nuclear magnetic resonance (NMR) spectroscopy, observing the olefinic,
J. Braz. Chem. Soc.. Publicado em: 2020-08
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3. Estudo de ligações pinadas com chapa de topo para aplicações em estruturas metálicas treliçadas tubulares planas / Study of pinned gusset plate connections for application in uniplanar trusses with circular hollow sections
Este trabalho apresenta o desenvolvimento de uma concepção estrutural para ligações de treliças metálicas tubulares de seção circular com chapa de topo através de um estudo teórico-experimental. Nesta concepção as extremidades das diagonais são superpostas e unidas por um único parafuso fazendo com que a ligação seja pinada. A colocação da
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/10/2011
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4. Estudo das estruturas de discordâncias cristalinas em arseneto de gálio
We employ ab initio calculations to investigate 90º partial dislocations in gallium arsenide. In a binary semiconductor like GaAs, two types of dislocations are present. In the a(ß) dislocation, there are two lines of arsenic (gallium) atoms on each side, bordering the geometric center of the dislocation core. For both the a ß and dislocations, we conside
Publicado em: 2009
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5. SYNTHESIS AND CHARACTERIZATION OF OXIMES LIGANDS AND THIOSEMICARBAZONES AND THEIR COMPLEXES / SÍNTESE E CARACTERIZAÇÃO DE LIGANTES OXIMAS E TIOSSEMICARBAZONAS E SEUS COMPLEXOS
This research shows the synthesis and characterization of five ligands and four complexes derived from oximes and thiosemicarbazones. It analyses the crystalline/molecular structures determined by X-ray difraction in monocrystals: the ligand 4- phenylthiosemicarbazone-isatin (Ligand 5), the complexes pyridine-salicylaldehyde-4- phenylthiosemicarbazone of Ni(
Publicado em: 2009
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6. Structural study of complexes of copper (II) as models metallic sites of enzymes with oxidative / Estudo estrutural de complexos de cobre (II) como modelos de sítios metálicos de enzimas com atividade oxidativa
We present the structural study, by x-rays diffraction, of two forms on the crystalline and molecular structures of the metal-organic single-crystal compounds Dicloro[N- benzoyl-N-(4-methylphenyl)-N-(2-pyridinyl)-guanidine)]copper(II). Such compound is known for the phenol oxidative catalictic bioactivity. The compound is a copper(II)-guanidine de- rivative
Publicado em: 2009
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7. Estudo da interação do vanádio (V) com ácidos [beta]-alaninoidroxâmico, glicinoidroxâmico e [alfa]-alaninoidroxâmico em solução aquosa $h [manuscrito] : $b uma abordagem a partir da DFT
The discovery of the potential insulin-mimetic properties of vanadium compounds has stimulated research about the clinical use of these compounds. The effects of different organic groups in the geometry, electronic structure and chemical properties of the vanadium coordination compounds are of fundamental importance to understand the chemical reactivity and
Publicado em: 2009
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8. Influencia de compostos carboxilicos e ions metalicos na degradação de neurotransmissores / Influence of carboxylate and metal ions on the degradation of neurotransmitters
Several neurological disorders are associated with improper catechoalmine regulation in the brain. Numerous researches have indicated that metallic ions can induce oxidative stress-dependent neurodegeneration of dopamine, and are responsible for the induction of neurodegenerative diseases. In previous work was verified that some carboxylates diminishes the o
Publicado em: 2007
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9. Desenvolvimento de catalisadores bifuncionais de óxido de zircônio modificado por óxidos de tungstênio e molibdênio contendo platina para a reação de isomerização de n-parafinas / Development of bifunctional catalysts on zircon oxide modify by tungsten and molybdenum oxides contain platinum for nparaffin isomerization
Bifunctional catalysts based on zircon oxide modified by tungsten (W = 10, 15 and 20 %) and by molybdenum oxide (Mo= 10, 15 e 20 %) containg platinum (Pt = 1%) were prepared by the polymeric precursor method. For comparison, catalysts the tungsten base was also prepared by the impregnation method. After calcinations at 600, 700 and 800 C, the catalysts were
Publicado em: 2007
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10. Silicon adsorption in single walled nanotubes
Using density functional (DF) calculations and Monte Carlo (MC) simulations we have investigated the main electronic and structural properties of silicon interacting with single walled carbon nanotubes. We have investigated the silicon adsorption externally and internally in the nanotubes surface. The total energies calculations and charge density plot prese
Brazilian Journal of Physics. Publicado em: 2006-09
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11. Síntese e Análise Estrutural de Complexos de Urânio(VI) com Hidrazonas, Semicarbazonas e Ligantes Relacionados. / Synthesis and Structural Analysis of Uranium(VI) Complexes with Hydrazones, Semicabazones and Related Ligands.
Uranyl complexes with ligands with oxygen and nitrogen donors have been extensively reviewed and they have aroused interest on account of their high stability, usefulness in selective chemical separations and their formation in higher coordination numbers, but quite a few complexes of hydrazone and semicarbazone ligands have been reported. This fact was the
Publicado em: 2006
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12. Preparation and characterization of mixed modified electrodes used in electrocatalytic hydrogenation of organic substrates / Preparação e caracterização de eletrodos modificados mistos e seu uso em hidrogenação eletrocatalítica de substratos orgânicos
This thesis describes the preparation of new modified electrodes (MEs) using the method of noble metal particles deposition like nickel, palladium and platinum in the surface of commum metals particles as cooper and iron. This new electrodes were denominated mixed MEs, and can show different caractheristics and present higher efficiency than others already s
Publicado em: 2006