Results 241 to 250 of about 1,356,161 (305)

Progressive saturation NMR relaxation

Physical Review B, 2001
The NMR spin-lattice relaxation rate, ${T}_{1}^{\ensuremath{-}1},$ can be measured precisely by progressive saturation. This efficient technique is useful when ${T}_{1}$ is long and the NMR signal is weak. We derive the quasiequilibrium spin response to excitation in the case of a Zeeman spectrum in the presence of quadrupolar interactions.
V. F. Mitrović, E. E. Sigmund, W. P. Halperin   +2 more
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NMR Relaxation in Heterogeneous Systems

Nature, 1970
THERE has recently been some discussion1,2 of the difficulties of interpreting nuclear magnetic resonance line broadening in complex heterogeneous suspensions. The discussion has been concerned with hindered rotation of solvent species, and it has been confined to proton magnetic relaxation. We report here a study of the relaxation phenomenon in a well
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Temperature Effect on NMR Surface Relaxation

SPE Annual Technical Conference and Exhibition, 2001
Abstract We present NMR relaxation experiments of water and oil confined in a series of calibrated porous media and natural rocks of different wettability, at various temperatures and magnetic fields. The longitudinal 1/T1 and transverse 1/T2 relaxation rates are interpreted with an original theoretical model which shows that the solid ...
S. Godefroy, M. Fleury, F. Deflandre, J.-P. Korb   +3 more
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Relaxation times and NMR signals

Magnetic Resonance Imaging, 1984
The strength of signals in magnetic resonance imaging (and the resulting image contrast) depends not just on the number density of the nuclei being detected, but also on the relaxation times, T1 and T2. The relationship of signal strength to relaxation time depends on the particular choice of pulse sequences used to produce the signals.
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Sodium NMR relaxation in porous materials

Journal of Magnetic Resonance, 2004
The NMR relaxation of hydrogen nuclei of a fluid in a porous material is generally interpreted in terms of the Brownstein-Tarr model, in which the relaxation rate of the signal is inversely proportional to the pore size. We have investigated whether this model can be applied to the relaxation of Na nuclei in a NaCl solution in a porous material.
Rijniers, L.A., Magusin, P.C.M.M., Huinink, H.P., Pel, L., Kopinga, K.   +4 more
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NMR Relaxation of Clay-Brine Mixtures

SPE Annual Technical Conference and Exhibition, 1998
Abstract Effective interpretation of nuclear magnetic resonance (NMR) logs in shaly sands requires an understanding of the NMR contribution of clays. Of particular importance is the role of clays in the rapidly relaxing part of the NMR signal.
A. Matteson, J.P. Tomanic, M.M. Herron, D.F. Allen, W.E. Kenyon   +4 more
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¹³C‐NMR relaxation in glycogen

Magnetic Resonance in Medicine, 1996
AbstractThis study is the first report on the multiexponential T2 relaxation of the 13C‐1 carbon of glycogen. In contrast to T1 relaxation, which does not display observable multiexponential decay behavior, T2 relaxation is described by a continuous distribution of T2 times.
K, Overloop, F, Vanstapel, P, Van Hecke
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The hamiltonians of NMR. Part IV: NMR relaxation

Concepts in Magnetic Resonance, 1994
AbstractUsing the methods presented in our previous discussions of the Hamiltonians of NMR, we describe the processes that lead to relaxation of spin systems. The same nomenclature and methods of Parts I, II, and III have been used to develop a formulation of time‐dependent operators.
Scott A. Smith, William E. Palke, J. T. Gerig   +2 more
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NMR relaxation in adsorbed water

Journal of Magnetic Resonance (1969), 1992
Abstract The NMR relaxation behavior of the proton magnetization in adsorbed water is investigated. Longitudinal as well as transverse relaxation of the adsorbed water as a whole shows a distinct nonexponentiality and the nature of this nonexponentiality is studied.
K Overloop, L van Gerven
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NMR Relaxation and Petrophysical Properties

AIP Conference Proceedings, 2011
NMR relaxation is routinely used in the field of geosciences to give basic petrophysical properties such as porosity, pore size distribution, saturation etc. In this tutorial, we focus on the pore size distribution deduced from NMR. We recall the basic principle used in the interpretation of the NMR signal and compare the results with other standard ...
Marc Fleury, Paola Fantazzini, Villiam Bortolotti, Jörg Kärger, Petrik Galvosas   +4 more
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