Resurrection of crushed magnetization and chaotic dynamics in solution NMR spectroscopy
Resurrection of crushed magnetization and chaotic dynamics in solution NMR spectroscopy
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DOI：
10.1126/science.290.5489.118
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发表时间：
2000-10-06
期刊：
影响因子：
56.9
通讯作者：
Warren, WS
中科院分区：
文献类型：
--
作者：
Lin, YY;Lisitza, N;Warren, WS
我们的实验和理论表明，两个容易观察到的效果，在解决方案核磁共振（NMR）辐射阻尼和偶极场相结合，产生奇异的自旋动力学（包括混沌演化），即使非常简单的序列。例如，在破碎机梯度之后看似微不足道的剩余磁化触发磁化的指数再增长，随后是非周期性湍流自旋运动。估计的李雅普诺夫指数表明时空混沌的发生和混沌吸引子的存在。这种效应导致了高度不可重复的实验衰变，放大了微小的不均匀性，如温度梯度。成像应用和其他NMR研究的后果进行了讨论。
We show experimentally and theoretically that two readily observed effects in solution nuclear magnetic resonance (NMR)-radiation damping and the dipolar field-combine to generate bizarre spin dynamics (including chaotic evolution) even with extraordinarily simple sequences. For example, seemingly insignificant residual magnetization after a crusher gradient triggers exponential regrowth of the magnetization, followed by aperiodic turbulent spin motion. The estimated Lyapunov exponent suggests the onset of spatial-temporal chaos and the existence of chaotic attractors. This effect Leads to highly irreproducible experimental decays that amplify minor nonuniformities such as temperature gradients. Imaging applications and consequences for other NMR studies are discussed.