Low Field Nmr
Mostrando 1-12 de 48 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. Droplet Size Distribution in Water-Crude Oil Emulsions by Low-Field NMR
This paper reports the droplet size distribution (DSD) measurements in 28 W/O (water/oil) crude oil emulsions prepared with two Brazilian oils (medium and heavy) under different shear conditions using both 10 g L-1 NaCl solution and water production by low field nuclear magnetic resonance (NMR, 2.2 MHz). The PFGSTE (pulsed-field gradient-stimulated echo) pul
J. Braz. Chem. Soc.. Publicado em: 12/08/2019
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3. Matéria Evaluation of zinc oxide nanoparticles influence on hydrophilic polymer matrix systems
ABSTRACT Hydrophilic polymer matrix systems (HPMSs) are a highly relevant tool for drugs delivery whose bioavailability is impaired by low hydrosolubility. Besides this, when associated with nanoparticles these systems can provide better control over release profile of the active drug, maintaining the posology. Since polyvinylpyrrolidone (PVP) and zinc oxide
Matéria (Rio J.). Publicado em: 06/12/2018
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4. Effect of pre-emulsified sesame oil on physical-chemical and rheological properties of pork batters
Abstract Physical-chemical and rheological properties of pork batters as affected by replacing pork back-fat with pre-emulsified sesame oil were investigated. Replacement of pork back-fat with pre-emulsified sesame oil, improved L* value, moisture and protein content, hardness, cohesiveness, and chewiness, declined a* value, fat content and energy, but not a
Food Sci. Technol. Publicado em: 20/07/2017
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5. 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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6. Solvent Effect on the Morphology of Lamellar Nanocomposites Based on HIPS
In this study, hybrid nanocomposites based on HIPS, high-impact polystyrene, were prepared in chloroform and in a 1:1 mixture of toluene and chloroform varying the quantity of organophilic montmorillonite. The morphology of the hybrid materials was investigated by X-ray diffraction (XRD) and proton relaxometry, determined in a low-field 1H nuclear magnetic r
Mat. Res.. Publicado em: 2015-02
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7. Análise do teor e da qualidade dos lipídeos presentes em sementes de oleaginosas por rmn de baixo campo
To choose among the variety of oleaginous plants for biodiesel production, the oil content of several matrices was determined through different low-field ¹H nuclear magnetic resonance (NMR) experiments with varied pulse sequences, namely single-pulse, spin-echo, CPMG, and CWFP. The experiments that involved the first three sequences showed high correlation
Quím. Nova. Publicado em: 2014
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8. Desenvolvimento de sistemas eletroquímicos acoplados a RMN de baixo e alto campo para análises in situ / Development of the electrochemical systms coupled to the low and high-field NMR for in situ analysis
Neste trabalho é descrito o desenvolvimento de sistemas eletroquímicos (EQ) acoplados com a RMN de baixo e alto campo para análises in situ. Para a análise EQ-RMN de baixo campo, foi construído um sistema eletroquímico para ser utilizado tanto em um espectrômetro RMN-DT (B0= 0,23 T) quanto em um sensor unilateral (B0= 0,4 T). A platina foi utilizada c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/04/2012
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9. Molecular dynamics and formation of domains in block copolymers studied by high and low resolution NMR / Dinâmica molecular e formação de domínios em copolímeros em bloco estudados por RMN de alta e baixa resolução
The main objective of this dissertation is the use of NMR methods to characterize the phase separation and, to some extent, the dynamics of the molecular segments in block copolymers. In the first part, NMR Spin Diffusion methods were explored in order to evaluate their performance as well as the main experimental difficulties. For that, a reference tri-bloc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/04/2012
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10. Programação de um sistema de controle de RF e aquisição de dados para um espectrômetro de RMN de baixo custo / Programming of a RF control sistem and data acquisition for a lowcost NMR spectrômeter
Este projeto teve como objetivo a construção e automatização de um espectrômetro de baixo custo que tem como principal aplicação a caracterização de meios porosos. Para realizar a caracterização de um meio poroso é necessário que o campo magnético externo aplicado não seja intenso para diminuir os problemas relacionados com a diferença de sus
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/02/2012
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11. 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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12. Supressão das anomalias de fase e batimentos laterais em espectros de RMN 13c obtidos com a sequência de precessão livre no estado estacionário
The Steady-State Free Precession (SSFP) sequence has been widely used in low-field and low-resolution imaging NMR experiments to increase the signal-to-noise ratio (s/n) of the signals. Here, we analyzed the Scrambled Steady State - SSS and Unscrambled Steady State - USS sequences to suppress phase anomalies and sidebands of the 13C NMR spectrum acquired in
Química Nova. Publicado em: 2010