993 resultados para Material Co-ordinates
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The reactivity of the mer-[RuCl3(dppb)H2O] complex (1) with di-hydrogen shows that the products formed depend on the conditions of the reaction, i.e., solvents and presence or absence of a base. The new mixed-valence complexes [(diop)ClRu-(h-Cl)(3)-RuCl(dppb)] (3), [(binap)CIRu-(p-Cl)(3)-RuCl(dppb)] (4), [(PPh3)(2)ClRu-(mu-Cl)(3)-RuCl(dppb)] (6), [(dppn)ClRu-(mu-Cl)(3)-RuCl(dppb)] (7), [(P-ptol(3))(2)ClRu-(mu-Cl)(3)-RuCl(dppb)] (8), [(SbPh3)(2)ClRu-(mu-Cl)(3)-RuCl(dppb)] (9), [(eta(6)-C6H6)Ru-(mu-Cl)(3)-RuCl(dppb)] (11) and the known mixed-valence [(dppb)CIRu-(mu-Cl)(3)-RuCl(dppb)] (5) and [(diop)ClRu-(mu-Cl)(3)-RuCl(diop)] (10) were synthesized from complexes (1) or (2) using a methodology developed in our research group. The known complexes [(dppb)ClRu-(mu-Cl)(2)-RuCl(dppb)] (12), [(dppb)(CO)Ru-(mu-Cl)(3)-RuCl(dppb)] (13) and [H2NEt2][(dppb)ClRu-(mu-Cl)(3)-RuCl(dppb)] (14) were synthesized by changing the reaction conditions between mer-[RuCl3(dppb)H2O] (1) and dihydrogen. The crystal structures of (5) and (11) were determined by single-crystal X-ray diffraction. Some of the complexes described here are effective pre-catalysts for the hydrogenation of imines. Preliminary results on the homogeneous hydrogenation of the imines Ph-CH2-N=CH-Ph and Ph-N=CH-Ph are presented. (C) 2004 Elsevier Ltd. All rights reserved.
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We have recently proposed an extension to Petri nets in order to be able to directly deal with all aspects of embedded digital systems. This extension is meant to be used as an internal model of our co-design environment. After analyzing relevant related work, and presenting a short introduction to our extension as a background material, we describe the details of the timing model we use in our approach, which is mainly based in Merlin's time model. We conclude the paper by discussing an example of its usage. © 2004 IEEE.
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Hydrogenated bulk Zn1-xCoxO samples were synthesized via standard solid-state reaction route with Co molar concentrations up to 15 at.%. Magnetic characterization demonstrates a room temperature ferromagnetic behavior associated to a paramagnetic Curie-Weiss component. Detailed microstructural analysis was carried out to exclude the presence of extrinsic sources of ferromagnetism. The magnetization increases linearly as a function of Co concentration. Hall measurements reveal an insulating character for the whole set of samples. In this context, the defect mediated magnetic coupling between the Co atoms under the scope of the bound magnetic polarons model is used to interpret the observed room temperature ferromagnetism. © 2012 Elsevier B.V. All rights reserved.
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This work studied the degradation of dipyrone, via electrochemical processes and via electro-Fenton reaction using a 4% CeO2/C gas diffusion electrode (GDE) prepared via modified polymeric precursor method. This material was used to electrochemically generate H2O2 through oxygen reduction. The mean crystallite sizes estimated by the Scherrer equation for 4% CeO2/C were 4 nm for CeO2-x (0 4 4) and 5 nm for CeO2 (1 1 1) while using transmission electron microscopy (TEM) the mean nanoparticle size was 5.4 nm. X-ray photoelectron spectroscopy (XPS) measurements revealed nearly equal concentrations of Ce(III) and Ce(IV) species on carbon, which contained high oxygenated acid species like CO and OCO. Electrochemical degradation using Vulcan XC 72R carbon showed that the dipyrone was not removed during the two hour electrolysis in all applied potentials by electro-degradation. Besides, when the Fenton process was employed the degradation was much similar when using cerium catalysts but the mineralization reaches just to 50% at -1.1 V. However, using the CeO2/C GDE, in 20 min all of the dipyrone was degraded with 26% mineralization at -1.3 V and when the Fenton process was employed, all of the dipyrone was removed after 5 min with 57% mineralization at -1.1 V. Relative to Vulcan XC72R, ceria acts as an oxygen buffer leading to an increase in the local oxygen concentration, facilitating H2O2 formation and consequently improving the dipyrone degradation © 2013 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Includes bibliography
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Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE
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Pós-graduação em Genética - IBILCE
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Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC
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Pós-graduação em Odontologia - FOA
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)