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Titolo:
FIELD-CYCLING NMR RELAXOMETRY OF MOLECULES UNDERGOING LEVY WALKS AT THE SURFACE OF FINE PARTICLES AND POROUS-GLASS
Autore:
ZAVADA T; STAPF S; BEGINN U; KIMMICH R;
Indirizzi:
UNIV ULM,SEKT KERNRESONANZSPEKTROSKOPIE D-89069 ULM GERMANY
Titolo Testata:
Magnetic resonance imaging
fascicolo: 5-6, volume: 16, anno: 1998,
pagine: 711 - 713
SICI:
0730-725X(1998)16:5-6<711:FNROMU>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIFFUSION;
Keywords:
POROUS MEDIA; FIELD-CYCLING; REORIENTATIONS MEDIATED BY TRANSLATIONAL DISPLACEMENTS; LEVY WALKS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
4
Recensione:
Indirizzi per estratti:
Citazione:
T. Zavada et al., "FIELD-CYCLING NMR RELAXOMETRY OF MOLECULES UNDERGOING LEVY WALKS AT THE SURFACE OF FINE PARTICLES AND POROUS-GLASS", Magnetic resonance imaging, 16(5-6), 1998, pp. 711-713

Abstract

Slow surface dynamics of solvents confined in the pore space of porous glass and fineparticles was studied by proton field-cycling relaxometry, Molecular reorientations mediated by translational displacements are shown to be an important low-frequency T-1-relaxation mechanism inporous media at low nuclear magnetic resonance (NMR) frequencies in the strong adsorption limit. This is revealed by the pronounced T-1-dispersion in this case while a flat one is observed for weak adsorption. The following nanoporous materials were examined in this respect: fineparticles of ZnO, TiO2, porous glass, Silanized surfaces lead to a somewhat steeper T-1-dispersion of non-polar cyclohexane than the native, i.e. polar, surfaces. On the other hand, there is no strong influence of the surface groups on the T-1(omega) slope of (polar) acetone, The results are discussed with reorientations mediated by translational displacements enhanced by Levy walks on the surface. (C) 1998 ElsevierScience Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 09:32:28