1H n.m.r. relaxation in bituminous coal and semicoke |
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Authors: | John A. Ripmeester Christiane Couture J.Anthony MacPhee Biswanath N. Nandi |
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Affiliation: | 1. Division of Chemistry, National Research Council of Canada, Ottawa, Ontario, K1A OR9, Canada;2. Energy Research Laboratories, Canada Centre for Mineral and Energy Technology, Department of Energy, Mines and Resources, 555 Booth Street, Ottawa, Ontario, K1A OG1, Canada |
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Abstract: | Temperature and frequency-dependent proton relaxation measurements, in conjunction with spin concentrations determined by e.s.r., have shown that for fresh and oxidized coal the relaxation mechanism involves spin-diffusion to paramagnetic centres and to rotating methyl groups on alkyl chains. 1H relaxation in semicokes is more complex; probably both direct relaxation to paramagnetic centres as well as spin-diffusion contribute. |
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Keywords: | coal semicoke n.m.r. |
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