Szutkowski Kosma, Furó István
Division of Physical Chemistry, Department of Chemistry, Royal Institute of Technology, Teknikringen 30/36, SE-10044 Stockholm, Sweden.
J Magn Reson. 2008 Dec;195(2):123-8. doi: 10.1016/j.jmr.2008.08.009. Epub 2008 Aug 28.
Current single-shot diffusion methods based on magnetization gratings suffer from low sensitivity due to small rf tip angles and, consequently, from inefficient use of the total equilibrium magnetization. Here, we propose and illustrate the use of a slightly modified form of the magnetization encoding scheme OUFIS for single-shot diffusion experiments. In a detailed theoretical and experimental analysis, we compare the performance of the proposed method to other encoding schemes such as the one-phase or two-phase DANTE and conclude that the OUFIS-based experiment is a superior one. The primary reason is that this scheme allows one to use a larger total pulse area. Hence, one can encode a far larger portion of the initial magnetization into a frequency grating before the onset of various nonlinear effects. In the experimental illustration, we present a single-shot measurement of multicomponent diffusion.
当前基于磁化光栅的单次扩散方法由于射频翻转角小而灵敏度较低,因此总平衡磁化的利用效率不高。在此,我们提出并说明了一种对磁化编码方案OUFIS稍加修改的形式用于单次扩散实验。在详细的理论和实验分析中,我们将所提出方法的性能与其他编码方案(如单相或两相DANTE)进行了比较,并得出基于OUFIS的实验更优的结论。主要原因是该方案允许使用更大的总脉冲面积。因此,在各种非线性效应出现之前,可以将初始磁化的更大比例编码到频率光栅中。在实验示例中,我们展示了多组分扩散的单次测量。