Telkki Ville-Veikko, Jokisaari Jukka
NMR Research Group, Department of Physical Sciences, University of Oulu, PO Box 3000, FIN-90014, Finland.
Phys Chem Chem Phys. 2009 Feb 28;11(8):1167-72. doi: 10.1039/b817727a. Epub 2009 Jan 8.
Self-diffusion of a fluid absorbed in a solid matrix is restricted by the walls of the matrix. We demonstrate that the local self-diffusion probability densities (propagators) of fluid molecules can be measured by position-exchange nuclear magnetic resonance spectroscopy (POXSY), and analysis of the shape of the propagators reveals the local size-distributions of the voids in the matrix. We also show that, in the case of rectangular voids, size-distribution can be calculated in a long diffusion-time limit without any assumptions about the shape of the distribution. Pinus sylvestris pine wood was used as a sample material in the experiments, and the results show that this method gives detailed information about the structure of wood.
吸收在固体基质中的流体的自扩散受到基质壁的限制。我们证明，流体分子的局部自扩散概率密度（传播子）可以通过位置交换核磁共振光谱法（POXSY）测量，并且对传播子形状的分析揭示了基质中孔隙的局部尺寸分布。我们还表明，在矩形孔隙的情况下，可以在长扩散时间极限下计算尺寸分布，而无需对分布形状做任何假设。实验中使用樟子松木材作为样品材料，结果表明该方法提供了有关木材结构的详细信息。
