脉冲梯度场增强的DQF-COSY实验t_1噪声研究(英文)

Abstract

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.以上理论结果得到我们实验结果的支持

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.