Fachgebiet Technische Physik II/Polymerphysik, Institute of Physics, Technische Universität Ilmenau, PO Box 100 565, 98684 Ilmenau, Germany.
J Magn Reson. 2011 Feb;208(2):256-61. doi: 10.1016/j.jmr.2010.11.014. Epub 2010 Nov 21.
Two-dimensional diffusion exchange experiments in the presence of a strong, static magnetic field gradient are presented. The experiments are performed in the stray field of a single sided NMR sensor with a proton Larmor frequency of 11.7 MHz. As a consequence of the strong and static magnetic field gradient the magnetization has contributions from different coherence pathways. In order to select the desired coherence pathways, a suitable phase cycling scheme is introduced. The pulse sequence is applied to study diffusion as well as the molecular exchange properties of organic solvents embedded in a mesoporous matrix consisting of a sieve of zeolites with a pore size of 0.8 nm and grain size of 2 μm. This pulse sequence extends the possibilities of the study of transport properties in porous media, with satisfying sensitivity in measurement times of a few hours, in a new generation of relatively inexpensive low-field NMR mobile devices.
介绍了在强静态磁场梯度存在下的二维扩散交换实验。实验是在单边 NMR 传感器的杂散场中进行的，质子拉莫尔频率为 11.7 MHz。由于强静态磁场梯度的存在，磁化强度来自于不同的相干路径。为了选择所需的相干路径，引入了一种合适的相位循环方案。该脉冲序列可用于研究扩散以及嵌入介孔基质中的有机溶剂的分子交换特性，介孔基质由具有 0.8nm 孔径和 2μm 晶粒尺寸的分子筛筛组成。该脉冲序列扩展了多孔介质中传输特性研究的可能性，在新一代相对廉价的低场 NMR 移动设备中，以几个小时的测量时间，实现了令人满意的灵敏度。
