Zhu Xiaoqin

Heteronuclear intermolecular single-quantum coherences in liquid nuclear magnetic resonance

This paper analyses the heteronuclear Cosy Revamped by Asymmetric Z-gradient Echo Detection pulse sequence. General theoretical expressions of the pulse sequence with arbitrary flip angles were derived by using dipolar field treatment and signals originating from heteronuclear intermolecular single-quantum coherences (iSQCs) in highly-polarized two spin-1/2 systems were mainly discussed in order to find the optimal flip angles. The results show that signals from heteronuclear iSQCs decay slower than those from intermolecular double-quantum coherences or intermolecular zero-quantum coherences. Magical angle experiments validate that the signals are from heteronuclear iSQCs and insensitive to the imperfection of radio-frequency flip angles. All experimental observations are in excellent agreement with theoretical predictions. The quantum-mechanical treatment leads to similar predictions to the dipolar field treatment.

Structure and chemical valence study of Srn+1RunO3n+1 (n = 1, 2, ∞) series

Effect of structure parameter n and its coupling with the connection mode among RuO6 octahedra of Srn+1RunO3n+1 (n = 1, 2, ?) are investigated. The gradually enhanced rotation and tilting effect with increasing n are observed in Srn+1RunO3n+1. Besides, the chemical valence of Ru is not changed, while the one of Sr gradually varies with increasing n, which highlights the great contribution of connection mode to the chemical environment. Our results show a strong n dependence on the connection mode between octahedra in Srn+1RunO3n+1 (n = 1, 2, ?).