The varying temperature pulse proton NMR method was adopted to determine the e-quilibrium moisture content of several Chinese and Australian coals. The pulse proton NMR spec-trometry is sensible to the hydrogen at dif...The varying temperature pulse proton NMR method was adopted to determine the e-quilibrium moisture content of several Chinese and Australian coals. The pulse proton NMR spec-trometry is sensible to the hydrogen at different physical state which occurs for water when temperature changes through 273 K. The equilibrium water,with some interactions to the coal surface, will not transform from one phase to another while the free water does. The measured results are reasonable comparing to the conventional gravimetric method.展开更多
Pulsed field gradient nuclear magnetic resonance （PFG NMR） has been performed to study the diffusion of organic solvents into semicrystalline polyethylene particles. Self-diffusion coefficients in different domains ...Pulsed field gradient nuclear magnetic resonance （PFG NMR） has been performed to study the diffusion of organic solvents into semicrystalline polyethylene particles. Self-diffusion coefficients in different domains of the sample can be extracted through a bi- exponential fit to the echo intensity attenuation, which allows the precise determination of the tortuosity of the polyethylene particles. Further exploration comes from the measurements with branched polyethylene particles and it was found that the diffusion in polymer phase contributed significantly to the slow component of the exponential decay curve. 2007 Jing Dai Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
基金This project was supported by UNDP Project DP/CPR/85/031 headed by Prof. Wang Zuna
文摘The varying temperature pulse proton NMR method was adopted to determine the e-quilibrium moisture content of several Chinese and Australian coals. The pulse proton NMR spec-trometry is sensible to the hydrogen at different physical state which occurs for water when temperature changes through 273 K. The equilibrium water,with some interactions to the coal surface, will not transform from one phase to another while the free water does. The measured results are reasonable comparing to the conventional gravimetric method.
基金This work was supported by the National Natural Science Foundation of China （No. 20490205 and No. 20406017） ； CSC-DAAD （PPP2004） project.
文摘Pulsed field gradient nuclear magnetic resonance （PFG NMR） has been performed to study the diffusion of organic solvents into semicrystalline polyethylene particles. Self-diffusion coefficients in different domains of the sample can be extracted through a bi- exponential fit to the echo intensity attenuation, which allows the precise determination of the tortuosity of the polyethylene particles. Further exploration comes from the measurements with branched polyethylene particles and it was found that the diffusion in polymer phase contributed significantly to the slow component of the exponential decay curve. 2007 Jing Dai Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
