中文摘要：

利用固体核磁共振实验研究了~（15）N标记的g-C_3N_4样品中的~（15）N-~（15）N空间相关性,在高场和魔角旋转条件下对比两种不同的脉冲序列PDSD和SHA＋的实验效果.发现当某个氮上连有质子的时候,脉冲序列SHA＋比PDSD可以更好地检测~（15）N原子间的极化转移.该研究可以为材料科学领域,特别是含氮掺杂的碳材料,提供一种有价值的研究方法.

英文摘要：

The performance of solid-state NMR proton-driven spin-diffusion （PDSD） andsecond-order Hamiltonian among analogous nuclei plus （SHA＋） sequences for probing 15N-15Nthrough-space correlations in 15N-labelled g-C3N4 samples were compared at high magnetic fieldswith moderate magic angle spinning （MAS） frequencies. It was found that, relative to the PDSDsequence, the SHA＋ sequence is more efficient in terms of yielding polarization transfer betweenthe 15N atoms as long as one of the nitrogen atoms bonds to protons. The results are useful inguiding the choice of solid-state nuclear magnetic resonance （SS-NMR） sequences for studyingnitrogen-doped carbon-based materials.