U.S.-China Cooperative Research (Chemistry): Dynamic Nuclear Polarization in Carbonaceous Solids

这是美国科罗拉多州立大学的Gary Maciel和中国科学院武汉物理研究所的叶朝辉的一个为期两年的合作项目。它由美国国家科学基金会和中国科学院联合主办。研究将集中于动态核极化（DNP）的持续发展和应用，这是一种强大的电子自旋/核。自旋翻倍。在核磁共振（NMR）实验中对既有磁性原子核又有未成对电子的材料增强核自旋极化的共振技术。DNP在描述中国和美国的煤炭和钻石时尤为重要。比如在中国和美国实验室制备的碳膜。对于煤的研究，将深入研究美国和某些中国煤的磁共振特性之间的显著差异，并探索结构模型来解释这两种类型的煤和这些具体差异。在金刚石薄膜的研究中，“缺陷”结构的性质将被阐明，并与薄膜的性质和制备方法有关。武汉物理研究所1.9 T DNP光谱仪使用的异常场强将为阐明这些样品中DNP现象的基本细节（通过DNP性质的场依赖性）和建立典型碳质固体DNP研究的最佳磁场提供一个很好的机会。

This is a two year collaborative project between Gary Maciel of Colorado State University and Ye Chaohui of the Wuhan Institute of Physics, Chinese Academy of Sciences. It is sponsored jointly by NSF and the Chinese Academy of Sciences. Research will focus on the continued development and application of dynamic nuclear polarization (DNP), a powerful electron.spin/nuclear.spin double.resonance technique that enhances the nuclear spin polarization in Nuclear Magnetic Resonance (NMR) experiments on materials containing both magnetic nuclei and unpaired electrons. DNP is especially important in the characterization of Chinese and U.S. coals and diamond.like carbon films prepared in Chinese and U.S. laboratories. For the coal studies, the striking differences between magnetic resonance properties measured for U.S. and certain Chinese coals will be examined in depth, and structural models will be explored for explaining both types of coals and these specific differences. In the diamond film studies, the nature of "defect" structures will be elucidated and related to film properties and preparation methods. The unusual field strength used in the 1.9 T DNP spectrometer in the Wuhan Institute of Physics will provide a good opportunity for elucidating fundamental details of the DNP phenomenon in these samples (via the field dependence of DNP properties) and for establishing the optimum magnetic field for DNP studies of typical carbonaceous solids.