射频场照射下同核体系的弛豫

根据WBR理论和同核体系的特点,构造出了一个相应的三维转动,利用Wigner旋转矩阵的特性并借助于计算机代数语言,计算出了射频场照射下同核体系完整的弛豫方程组.在此基础上,给出了射频场照射下纵向与横向弛豫时间的计算公式,并从理论上研究了射频场的照射对同核体系弛豫的影响.研究结果表明:1)射频场的照射对同核体系的弛豫有一定程度的影响.2)在射频场的照射下,同核体系的纵向弛豫时间T1小于无射频场时的T1,而横向弛豫时间T2大于无射频场时的T2.3)纵向弛豫时间T1随射频场的增强而逐渐减小,横向弛豫时间T2随射频场的增强而逐渐增大. 关键词： 核磁共振 弛豫 射频场 三维转动

Relaxation of homonuclear system with RF irradiation

According to WBR theory and the character of homonuclear system,the relaxation equations of homonuclear system with RF irradiation are deduced by means of the three-dimensional Wigner rotation matrix.The computation formulas of transverse and longitudinal relaxation with RF radiation are proposed,and the effects of RF irradiation on relaxation are investigated.Finally,the following conclusions are gained.(1)The RF irradiation has effect on the relaxation course in a homonuclear system to some extent. (2)The longitudinal relaxation time T 1 with RF irradiatoin is shorter than that without RF irradiation,while the transverse relaxation time T 2 with RF irradiation is longer than that without RF irradiation.(3)With the growth of RF irradiation,T 1 is reduced,while T 2 is increased.