Counterion
Mostrando 1-12 de 103 artigos, teses e dissertações.
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1. ORGANOCATÁLISE ENANTIOSSELETIVA: EVOLUÇÃO E ASPECTOS RECENTES
In the last two decades, enantioselective organocatalysis has established itself as one of the three pillars of asymmetric catalysis. The rapid growth in the area is due to the rationalization of organocatalysis based on the generic modes of catalyst activation, being applied to several types of reactions, in a rather generic and predictable way and providin
Quím. Nova. Publicado em: 27/05/2019
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2. Molecular Dynamics Simulations of Cetyltrimethylammonium Bromide (CTAB) Micelles and their Interactions with a Gold Surface in Aqueous Solution
Surfactants are molecular structures with remarkable physicochemical properties and applications. Most of their characteristics are due to their ability to promote aggregation and interactions with different interfaces. The scarcity of theoretical studies dedicated to evaluating the forces involved in these interactions prompted us to propose other models ca
J. Braz. Chem. Soc.. Publicado em: 2018-01
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3. EXPERIMENTAL STUDY ON THE COLLABORATIVE DRAG REDUCTION PERFORMANCE OF A SURFACTANT SOLUTION IN GROOVED CHANNELS
Abstract Turbulence with a relatively larger vortex is obtained in drag-reducing surfactant solution, which provides an excellent condition for the application of small scale grooves. In this work, the coupling drag reduction performance of surfactant solution and grooves was experimentally investigated to explore the complementary possibility between their
Braz. J. Chem. Eng.. Publicado em: 2017-01
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4. A Systematic Procedure to Develop a Capillary Electrophoresis Method Using a Minimal Experimental Data
The choice of an appropriate background electrolyte (BGE) and its components for capillary electrophoresis analysis is the main step in capillary electrophoresis method development. The use of an inadequate co-ion component could lead to asymmetrical peaks and selecting an inappropriate counter-ion could affect the buffer capacity and the pH of the BGE, lead
J. Braz. Chem. Soc.. Publicado em: 2016-11
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5. ASSOCIATION OF BRANCHED POLYETHYLENE IMINE WITH SURFACTANTS IN AQUEOUS SOLUTION
Three polymer-surfactant systems comprised of branched polyethylene imine (PEI) with an anionic surfactant (sodium dodecylsulfate; SDS), a cationic surfactant (tetradecyltrimethylammonium bromide; TTAB), and a zwitterionic surfactant (
N -tetradecyl-N ,N -dimethyl-3-ammonio-1-propanesulfonate; SB3-14) were stQuím. Nova. Publicado em: 2015-07
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6. Aplicação da técnica de elipsometria de emissão para caracterização de materiais luminescentes
In this work we demonstrated the potential of the emission ellipsometry in the scope of the Stokes theory for electromagnetic field to the photophysics study of luminescent materials, in addition we introduce a new methodology using an achromatic quarter-wave plate. Moreover, the use of linearly polarized light allowed "selectively" the study of various phot
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/02/2012
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7. Chitosan as flocculant agent for clarification of stevia extract
Stevia is used as a sweetener due to its low calorific value and its taste, which is very similar to that of sucrose. After extraction from dried leaves, stevia extract is dark in colour, and therefore needs to be whitened to increase acceptance by consumers. In this study we tested chitosan, a cationic polyelectrolyte, as flocculant agent for the whitening
Polímeros. Publicado em: 30/10/2012
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8. Solventes verdes para biopolímeros: síntese e aplicação de líquidos iônicos na derivatização de celulose / Green solvents for biopolymers: synthesis of ionic liquids and their use in derivatization of cellulose
The work reported has the target of studying the acylation of cellulose under homogeneous reaction conditions. Imidazolium-based ionic Liquids (ILs) were employed as solvents, and the reaction was assisted by a microwave. These following processes have been studied: Optimization of the synthesis of ILs; ii) Effects of the structure of ILs on the dissolution
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/10/2011
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9. Influência do contra-íon usado na eletrossíntese do polipirrol em sua resposta como biossensor eletroquímico após a imobilização da polifenol oxidase / Influence of counter-ion used in the electrosynthesis of polypyrrole in your response as electrochemical biosensors after polyphenol oxidase immobilization
Neste trabalho, foram fabricados biossensores amperométricos a partir do uso da polifenol oxidase (PFO), obtida do abacate como fonte enzimática, imobilizada em filmes de polipirrol (PPI) e que foram eletrossintetizados em meio de três diferentes eletrólitos de suporte (NaCl e NaClO4 e NaDDS). O método de imobilização enzimática foi o da adsorção,
Publicado em: 2009
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10. Influência do contra-íon molibdênio nas propriedades do pigmento SnO2: Cr / Influence of the molybdenum counterion in the properties of SnO2:Cr pigments
SnO2 pigments, when doped with chromium, lead to violet or purple colors, depending on chromium oxidation state. There is a need to control the chromophore oxidation state, as Cr(VI) is toxic and carcinogenic, while Cr(III) leads to no risk to living beings. Cr(VI) formation may be avoided with the addition of counterions, that lead to a charge imbalance. In
Publicado em: 2008
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11. SÃntese, caracterizaÃÃo e propriedades fotocrÃmicas da sais derivados do Ãcido N-(3,5-dinitrobenzoil)-α-fenilglicina
The preparation and characterization of salts derived from N-(3,5- dinitrobenzoyl)-α-phenylglycine was carried out by using protonated amines as counter-ion, as follows: NH4 + (DNBAm), (CH3-CH2-)2NH2 + (DNBD), (CH3-CH2-CH2- )NH3 + (DNBP), (CH3-CH2-CH2-CH2-)NH3 + (DNBBu) and (CH3-CH2-)3NH+ (DNBT). These salts showed photocromic effect with ultraviolet (U
Publicado em: 2008
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12. Estudo do equilibrio de fases e de estruturas de complexos formados entre polietilenoiminas e dodecilsulfato / Phase equilibria and structural study of polyethyilenoimine and dodecylsulfate complexes
Polyelectrolytes associate strongly with oppositely charged surfactants in water, being able to generate liquid crystalline phases with interesting supramolecular structures. The geometry of the liquid crystalline phase depends on parameters such as: concentration, surfactant/monomer ratio, polymer characteristics and presence of cosolvents. The objective of
Publicado em: 2007