Spin Lattice Relaxation
Mostrando 1-12 de 83 artigos, teses e dissertações.
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1. Development and characterization of photoprotective formulations containing keratin particles
This work deals with development and evaluation of MFQ protective formulation, which contains two organic filters, namely: octyl-p-methoxycinnamate (OMC) and benzophenone-3 (BP-3); a photostabilizing agent called ethylhexylmethoxycrylene (EHMCR) and keratin particles. The MFQ formulation was evaluated in order to measure its pH, spin-spin lattice relaxation
Braz. J. Pharm. Sci.. Publicado em: 20/12/2019
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2. Time domain NMR evaluation of poly(vinyl alcohol) xerogels
Abstract Poly(vinyl alcohol) (PVA)-based chemically cross-linked xerogels, both neat and loaded with nanoparticulate hydrophilic silica (SiO2), were obtained and characterized mainly through time domain NMR experiments (TD-NMR). Fourier-transform infrared (FT-IR) and wide angle X-ray diffraction (WAXD) analyses were employed as secondary methods. TD-NMR, thr
Polímeros. Publicado em: 08/08/2016
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3. USO DA RMN DE BAIXA RESOLUÇÃO NA AVALIAÇÃO DA DINÂMICA MOLECULAR DO Origanum vulgare
In this work, proton NMR relaxometry was used to measure the behavior of spin-lattice relaxation time with T1H as the time constant, and also of spin-spin relaxation time with the time constant T2H. These relaxometry parameters were determined to better understand the changes in the main structures present in commercial and in nature forms of origanum. The T
Quím. Nova. Publicado em: 2015-03
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4. Inorganic-organic hybrids based on poly (ε-Caprolactone) and silica oxide and characterization by relaxometry applying low-field NMR
Poly (ε-caprolactone) (PCL) based hybrids containing different amounts of modified (Aerosil® R972) and unmodified (Aerosil® A200) silica oxide were prepared employing the solution method, using chloroform. The relationships of the amount of nanofillers, organic coating, molecular structure and intermolecular interaction of the hybrid materials were invest
Mat. Res.. Publicado em: 25/09/2012
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5. Preparação do composto de associação entre citrato de ródio(II) e β-ciclodextrina
Inclusion compound of rhodium(II) citrate with β-cyclodextrin in a 1:1 molar ratio was prepared using freeze-drying method. X-ray diffactometry, thermal analysis (TG/DTG/DSC), infrared and ¹H-NMR with ¹H spin lattice relaxation (¹H T1) measurements and 13C techniques were used to characterize the system prepared. The results indicated the formation of in
Química Nova. Publicado em: 2012
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6. Evaluation of PHB/Clay nanocomposite by spin-lattice relaxation time
Poly(3-hydroxybutyrate) (PHB) based on nanocomposites containing different amounts of a commercial organically modified clay (viscogel B7) were prepared employing solution intercalation method. Three solvents, such as: CHCl3, dimethylchloride (DMC) and tetrahydrofuran (THF) were used. The relationship among the processing conditions; molecular structure and
Materials Research. Publicado em: 2008-12
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7. Um novo mÃtodo para investigar cinÃticas de polimerizaÃÃo baseado em RMN
Nowadays, research and development of polymer synthesis procedures are part of a technological branch which is quit intensive. This development depends, partially, on the ability of following and understanding the polymerization kinetics of these materials. For instance, mechanic stiffness of a polymer depends on size of its chains. On the other hand, for ch
Publicado em: 2007
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8. Lithium dynamics in molybdenum disulfide intercalation compounds studied by nuclear magnetic resonance
Cluster architecture and lithium motion dynamics are investigated in nanocomposites formed by the intercalation of lithium and a dialkylamine (diethylamine, dibutylamine and dipentylamine) in molybdenum disulfide by means of 7Li Nuclear Magnetic Resonance (NMR) technique. The present contribution illustrates the potential of the NMR techniques in the study o
Brazilian Journal of Physics. Publicado em: 2006-03
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9. Caracterização da estrutura de curto alcance de cimentos de cinza de casca de arroz através da espectroscopia por ressonância magnética nuclear de alta resolução / Characterization of the short range structure of rice husk ash cements studied by high-resolution nuclear magnetic resonance
A cinza obtida da queima controlada da casca de arroz é um material que apresenta propriedades pozzolânicas: reage na presença de água e dióxido de cálcio produzindo silicato de cálcio hidratado (C-S-H), o material que confere a resistência mecânica aos cimentos. Portanto, a cinza de casca de arroz é um material de potencial interesse para o desenv
Publicado em: 2002
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10. Nuclear magnetic resonance study of proton conductor HPb2Nb3O10. nH2O. / Estudo por Ressonância Magnética Nuclear do Condutor Protônico HPb2Nb3O10. nH2O.
The protonic conductor HPb2Nb3O10. nH2O , was studied by pulsed Nuclear Magnetic Resonance (NMR) of ANTPOT.1H. The temperature dependence of the spin-lattice relaxation rate (1/T IND.1) and line width, reflect the mobility of the protonic species present in this material. The onset of ionic and molecular motions produces a strong narrowing of the line at tem
Publicado em: 1998
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11. Construction of and auto-balanced ac suceptometer and study of eletronic conductor polymers for magnetic susceptibility and magnetic resonance. / Construção de um Susceptômetro AC Autobalanceado e Estudo de Polímeros Condutores Eletrônicos por Susceptibilidade Magnética e Ressonância Magnética.
A mutual inductance bridge which may be used for automatic measurement of ac magnetic susceptibilities from 4 K to room temperature, at frequencies up to 1 kHz, is described. The susceptometer employs an alternative and new arrangement for the probe. The coil set is kept at room temperature and moves in such a way to place the sample in the center of each of
Publicado em: 1998
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12. Estudo dos ions benzenossulfonato, benzoato e anilinio em soluções micelares atraves dos tempos de relaxação de 13C de ressonacia magnetica nuclear
Carbon-13 spin-lattice relaxation times were used to characterize the behavior of ionic solutes in isotropic micellar solutions. Threee monosubstituted benzene were analyzed, benzenesulfonate, benzoate and anilinium ions, in micellar solutions prepared using the surfactants alkyltrimetylammonium bromide (C10, C14 and C16), decylammonium chloride, potassium d
Publicado em: 1990