Nuclear magnetic resonance and dielectric noise study of spectral densities and correlation functions in the glass forming monoalcohol 2-ethyl-1-hexanol

2011 ◽  
Vol 135 (17) ◽  
pp. 174511 ◽  
Author(s):  
S. Schildmann ◽  
A. Reiser ◽  
R. Gainaru ◽  
C. Gainaru ◽  
R. Böhmer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Correlation Functions ◽  
Spectral Densities ◽  
Glass Forming ◽  
Nuclear Magnetic

Thermodynamical properties of glass forming systems: A Nuclear Magnetic Resonance analysis

2011 ◽  
Vol 357 (2) ◽  
pp. 286-292 ◽  
Author(s):  
Francesco Mallamace ◽  
Caterina Branca ◽  
Carmelo Corsaro ◽  
Jeroen Spooren ◽  
Sow-Hsin Chen ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nuclear Magnetic Resonance Analysis ◽  
Glass Forming ◽  
Resonance Analysis ◽  
Thermodynamical Properties ◽  
Nuclear Magnetic

Slow Motion of Confined Molecules: NMR and Broadband Dielectric Spectroscopy Investigations

2008 ◽  
Vol 8 (2) ◽  
pp. 887-893 ◽  
Author(s):  
Özlen F. Erdem ◽  
André Pampel ◽  
Dieter Michel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Ethylene Glycol ◽  
Spin Relaxation ◽  
Dielectric Spectroscopy ◽  
Proton Spin ◽  
Magic Angle ◽  
Glass Forming ◽  
Broadband Dielectric Spectroscopy ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) and broadband dielectric spectroscopy are used to investigate the dynamics of small glass-forming molecules confined to restricted geometries. Ethylene glycol molecules are embedded in the supercages of NaX zeolites. The combined application of NMR and broadband dielectric spectroscopy advances the understanding of the slowing down of the motion near the glass transition temperature of these confined molecules. In combination with nuclear spin relaxation and nuclear magnetic resonance spectroscopy, dielectric relaxation studies on glass forming molecules allow conclusions on the character of the motion. High resolution 1H magic angle spinning (MAS) NMR measurements not only enable a characterisation of the state of the adsorbed molecules via a chemical shift analysis. By means of an analysis of MAS spinning sidebands we may also estimate a correlation time the meaning of which will be discussed in comparison to the results of longitudinal proton spin relaxation measurements. In addition to broadband dielectric spectroscopy slow molecular motions of partially deuterated ethylene glycol adsorbed in NaX are studied by means of 2H NMR line-shape analysis.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

Nuclear magnetic resonance microscopy

1989 ◽  
Vol 47 ◽  
pp. 828-829
Author(s):  
Paul C. Lauterbur
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Signal To Noise ◽  
Field Gradients ◽  
Useful Signal ◽  
Magnetic Field Gradients ◽  
Observation Times ◽  
Nuclear Magnetic

Nuclear magnetic resonance imaging can reach microscopic resolution, as was noted many years ago, but the first serious attempt to explore the limits of the possibilities was made by Hedges. Resolution is ultimately limited under most circumstances by the signal-to-noise ratio, which is greater for small radio receiver coils, high magnetic fields and long observation times. The strongest signals in biological applications are obtained from water protons; for the usual magnetic fields used in NMR experiments (2-14 tesla), receiver coils of one to several millimeters in diameter, and observation times of a number of minutes, the volume resolution will be limited to a few hundred or thousand cubic micrometers. The proportions of voxels may be freely chosen within wide limits by varying the details of the imaging procedure. For isotropic resolution, therefore, objects of the order of (10μm) may be distinguished.Because the spatial coordinates are encoded by magnetic field gradients, the NMR resonance frequency differences, which determine the potential spatial resolution, may be made very large. As noted above, however, the corresponding volumes may become too small to give useful signal-to-noise ratios. In the presence of magnetic field gradients there will also be a loss of signal strength and resolution because molecular diffusion causes the coherence of the NMR signal to decay more rapidly than it otherwise would. This phenomenon is especially important in microscopic imaging.

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