Theory of polymer relaxation times in semidilute solutions. I : mode relaxation

1993 ◽  
Vol 3 (4) ◽  
pp. 477-486 ◽  
Author(s):  
Y. Shiwa
Keyword(s):  
Relaxation Times ◽  
Polymer Relaxation ◽  
Semidilute Solutions

THEORY OF POLYMER RELAXATION TIMES IN SEMI-DILUTE SOLUTIONS

1995 ◽  
Vol 09 (01) ◽  
pp. 57-67 ◽  
Author(s):  
YASUHIRO SHIWA
Keyword(s):  
Relaxation Time ◽  
Hydrodynamic Interaction ◽  
Relaxation Times ◽  
Excluded Volume ◽  
Dilute Solutions ◽  
Gradual Reduction ◽  
Polymer Relaxation ◽  
Dilute Polymer Solutions ◽  
Continuous Approach ◽  
Crossover Behavior

The explicit crossover behavior of the longest relaxation time for the dilute and semi-dilute polymer solutions is presented. Gradual reduction of the excluded-volume and the hydrodynamic interaction due to screening is taken into account along with the entanglement effect. The result reveals a continuous approach to a reptation-like asymptote with increasing concentration.

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.

On relaxation times

1999 ◽  
Vol 169 (10) ◽  
pp. 1163
Author(s):  
V.L. Vaks ◽  
V.V. Mityugov
Keyword(s):  
Relaxation Times
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