论文标题

在不稳定,不均匀领域中应用于磁共振实验的一致性途径的现代化视图

A Modernized View of Coherence Pathways Applied to Magnetic Resonance Experiments in Unstable, Inhomogeneous Fields

论文作者

Beaton, Alec A., Guinness, Alexandria, Franck, John M.

论文摘要

在最近几十年中,在较低的频率以及在不均匀和/或时间变量领域中进行实验的价值已增长。例如,对水合动力学的纳米级异质性的兴趣需要越来越复杂和自动化的测量,该测量将在低场处部署过度障碍动态核极化(ODNP)。这些方法的开发提出了各种挑战,促使我们开发了传统模式的标准化替代方案,用于获取和分析绝大多数当代核磁共振(NMR)研究所采用的相干途径信息。具体而言,在经过良好测试,稳定的NMR系统上,在高度优化的,均匀的磁场中运行经过良好测试的脉冲序列,传统硬件和软件通过平均数字化数据的3/4和127/128之间的平均和丢弃,迅速隔离了有意义的数据子集。相比之下,此处实施的域彩色连贯传输(DCCT)架构的最新进展刺激了域彩色连贯传递(DCCT)架构,建立在沿脉冲相位周期域的傅立叶变换的长期概念上,以启用数据可视化,以更完全反映这些NMR实验的丰富物理学。除了讨论一般DCCT模式和相关绘图方法的轮廓和实施外,该手稿还提出了一系列算法,这些算法可提供可靠的相位,避免基线失真以及通过信号相关的相关噪声中的背景噪声中相对较弱的信号实现相对较弱的信号的能力。可视化原始数据的方法以及其指导开发的处理程序应直接应用于或轻松扩展到面临类似挑战的其他技术。

Over recent decades, the value of conducting experiments at lower frequencies and in inhomogeneous and/or time-variable fields has grown. For example, an interest in the nanoscale heterogeneities of hydration dynamics demands increasingly sophisticated and automated measurements deploying Overhauser Dynamic Nuclear Polarization (ODNP) at low field. The development of these methods poses various challenges that drove us to develop a standardized alternative to the traditional schema for acquiring and analyzing coherence pathway information employed by the overwhelming majority of contemporary Nuclear Magnetic Resonance (NMR) research. Specifically, on well-tested, stable NMR systems running well-tested pulse sequences in highly optimized, homogeneous magnetic fields, traditional hardware and software quickly isolate a meaningful subset of data by averaging and discarding between 3/4 and 127/128 of the digitized data. In contrast, spurred by recent advances in the capabilities of open-source libraries, the domain colored coherence transfer (DCCT) schema implemented here builds on the long-extant concept of Fourier transformation along the pulse phase cycle domain to enable data visualization that more fully reflects the rich physics underlying these NMR experiments. In addition to discussing the outline and implementation of the general DCCT schema and associated plotting methods, this manuscript presents a collection of algorithms that provide robust phasing, avoidance of baseline distortion, and the ability to realize relatively weak signals amidst background noise through signal-averaged correlation alignment. The methods for visualizing the raw data, together with the processing routines whose development they guide should apply directly to or extend easily to other techniques facing similar challenges.

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