MODIFIED SPIN-ECHO METHOD FOR MEASURING NUCLEAR RELAXATION TIMES
MODIFIED SPIN-ECHO METHOD FOR MEASURING NUCLEAR RELAXATION TIMES
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DOI：
10.1063/1.1716296
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发表时间：
1958-01-01
影响因子：
1.6
通讯作者：
GILL, D
中科院分区：
文献类型：
--
作者：
MEIBOOM, S;GILL, D
N液体等效核体系的磁极化弛豫可用Bloch引入的两个弛豫时间T₁和T2来描述。？纵向弛豫时间T₁表征了极化分量在外加磁场方向上接近平衡的程度。横向弛豫时间T2表征了横向分量衰减到零的速率，并决定了核磁共振的线宽。在液体中，T2可以等于许多秒，对应于一个周期的一小部分的线宽。如此长的驰豫时间不能通过直接测量线宽来确定，因为即使在最好的磁体中，样品上方的磁场的不均匀也会对观察到的线宽产生非常显著的贡献。
N liquids the relaxation of the magnetic polarization of a system of equivalent nuclei can be described by two relaxation times T₁ and T2 introduced by Bloch. ¹ The longitudinal relaxation time T₁ characterizes the approach to equilibrium of the polarization component in the direction of the external magnetic field. The transverse relaxa-tion time T2 characterizes the rate at which the transverse component decays to zero, and determines the line width of the nuclear magnetic resonance. In liquids T2 can amount to many seconds, corresponding to a line width of a fraction of a cycle. Such long relaxation times cannot be determined by direct line-width measurement, as even in the best magnets the inhomogeneity of the magnetic field over the sample will give a very appreciable contribution to the observed line width.