Nmr Relaxation
Mostrando 1-12 de 179 artigos, teses e dissertações.
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1. NMR Relaxometry Applied to Chemical Studies of Paramagnetic Metal Cation Complexes: Fundamentals and Applications
Low field time-domain nuclear magnetic resonance (TD-NMR) relaxometry of paramagnetic metal cations (PMC) has been widely used to study and improve contrast agents for magnetic resonance imaging (MRI). However, despite its remarkable potential, TD-NMR is rarely used to study PMC complexes, and coordination compounds in non-biomedical application. Therefore,
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Non-Invasive Detection of Adulterated Olive Oil in Full Bottles Using Time-Domain NMR Relaxometry
A fast procedure using time-domain nuclear magnetic resonance (TD-NMR) to detect olive oil adulteration with polyunsaturated vegetable oils in filled bottles is proposed. The 1H transverse relaxation times (T2) of 37 commercial samples were measured using low-field nuclear magnetic resonance (LF-NMR) spectrometer and a unilateral nuclear magnetic resonance (
J. Braz. Chem. Soc.. Publicado em: 2017-02
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3. Analysis of Water in the Chicken Eggshell Using the 1H Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy
ABSTRACT The water content of the chicken eggshell has a major influence on gas (CO2 and O2) permeability. Inappropriate water loss during the incubation period increases embryo mortality and decreases chick quality. So far only the procedures that enable to determine the total water content in the eggshell have been described and developed. Our analysis of
Rev. Bras. Cienc. Avic.. Publicado em: 2016-12
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4. 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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5. Influence of PLGA and PLGA-PEG on the dissolution profile of oxaliplatin
Abstract Oxaliplatin was inserted into polymeric matrices aiming to study the interaction of this drug with these polymers and its capability to diffuse to the environment. Tested polymers were: (1) polyethylene glycol (PEG), (2) poly(lactic-co-glycolic acid) (PLGA), and (3) a copolymer of them (PLGA-PEG). The latter two were synthesized by us using polycond
Polímeros. Publicado em: 07/06/2016
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6. 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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7. Estudo de propriedades petrofísicas de rochas sedimentares por Ressonância Magnética Nuclear / Petrophysical properties study of sedimentary rocks by Nuclear Magnetic Resonance
The Nuclear Magnetic Resonance (NMR) technique is one of the most versatile techniques for scientific research, specially for the study of dynamics, structure and conformational of materials. In particular, its application in oil science is one of its first routine applications. Methodologies developed specifically to match this scientific community proved t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/05/2012
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8. Estudo de cerâmicas porosas de alumina através da medida de tempos de relaxação via ressonância magnética nuclear / Characterization of porous alumina ceramics through measurement of nuclear magnetic resonance relaxation times
A medida de tempo de relaxação longitudinal (T1) e transversal (T2) de ressonância magnética nuclear (RMN) é muito utilizada para análise de meios porosos na área do petróleo. Esses tempos de relaxação estão relacionados com tamanho dos poros. As cerâmicas, dependendo da sua temperatura de sinterização, apresentam uma porosidade intrínseca, ma
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/03/2012
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9. 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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10. 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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11. Aplysfistularine: a novel dibromotyrosine derivative isolated from Aplysina fistularis
The new dibromotyrosine derivative 3,5-dibromo-4-[3'dimethylamonium]propoxyphenyl]-N,N,N-trimethylethanamonium, here referred to as aplysfistularine (1), was isolated from the marine sponge Aplysina fistularis along with 2-(3,5-dibromo-4methoxyphenyl)-N,N,N-trimethylethanamonium (2), aplysterol (3) and 24,28-didehydroaplysterol (4). Their identification was
Quím. Nova. Publicado em: 2012
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12. Structure and dynamics of poly(9,9-dioctylfluoren-2,7-co-benzothiadiazole) (F8BT) and correlations with its electrical properties / Estrutura e dinâmica molecular do poly (9,9-dioctylfluoren-2,7-diyl-co-benzothiadiazole) (F8BT) e correlações com suas propriedades elétricas.
The PHD project has two main goals. The first one is specifically related to investigations on molecular dynamics, structural conformations and packing of polyfluorene-based polymers. For this purpose, Wide Angle X-Ray Diffraction (WAXD), Solid-State Nuclear Magnetic Resonance (NMR) and Dynamical-Mechanical Thermal Analysis (DMTA) are being used as the main
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/09/2011