脉冲梯度场增强的DQF-COSY实验t_1噪声研究(英文)  

P TYPE GRADIENT ENHANCED DQF COSY EXPERIMENTS SHOW LOWER t 1 NOISE THAN N TYPE *

作　　者：林国兴[1,2] 廖新丽[1,2] 林东海[1,2] 郑绍宽 陈忠[1,2] 吴钦义 

机构地区：[1]厦门大学化学系 [2]厦门大学物理系

出　　处：《波谱学杂志》1999年第1期17-18,共2页Chinese Journal of Magnetic Resonance

摘　　要：脉冲相位的不稳定性是导致二维谱中的ｔ１噪声的原因之一．本文从理论上和实验上对脉冲相位不稳定性所引起的ｔ１噪声进行了研究．从角动量算符Ｉｘ，Ｉｙ和Ｉｚ推导中发现，由于磁化矢量在Ｐ型和Ｎ型ＤＱＦＣＯＳＹ实验的脉冲梯度场中进动方向的内在差异，一部分脉冲相位误差在Ｐ型ＤＱＦＣＯＳＹ实验会被重聚掉，在Ｎ型ＤＱＦＣＯＳＹ实验中却会被加重．因此Ｐ型ＤＱＦＣＯＳＹ实验的ｔ１噪声比Ｎ型小．理论推导还得到ｔ１噪声在Ｐ型和Ｎ型中的理论比值为３∶１１．t 1 noise, stemming from the instabilities of pulse phases in 2D spectroscopy, has been investigated theoretically as well as experimentally. Based on the angular momentum operator I x,I y,I z formalism, our deductions show that the different precessing directions of the magnetization between P type and N type gradient enhanced DQF COSY experiments result in that P type gradient enhanced DQF COSY experiments refocus the phase errors of pulses, while N type gradient enhanced DQF COSY experiments strengthen the effect of the phase errors of pulses. Therefore, t 1 noise in P type gradient enhanced DQF COSY experiments is lower than that in N type. In addition, the theoretical ratio of P type to N type is 3∶11, which is supported by our experimental results.

关 键 词：NMR DQF-COSY 脉冲梯度场 t1噪声 积算符 

分 类 号：O482.532[理学—固体物理]