CPMG序列(Carr-Purcell-Meiboom-Gill Sequence)是核磁共振(NMR)和磁共振成像(MRI)中的一种核心脉冲序列,主要用于精确测量横向弛豫时间(T2)。其通过高频施加180°复相脉冲,有效消除磁场不均匀性对弛豫信号的干扰,从而获得样品本征T2值。以下从原理、结构、优势和应用场景展开说明。 一、CPMG序列的基本...
DNA中含氮碱基为ATCG RNA中碱基为AUCG。RNA和DNA只有尿嘧啶和胸腺嘧啶区别，其余相同 A腺嘌呤 G鸟嘌呤 C胞嘧啶 T胸腺嘧啶 U尿嘧啶 密码子配对为A配对T(U) C,G配对。核酸分为两种即DNA和RNA。核酸的组成包括三部分 即碱基 磷酸 核糖（5碳糖）DNA即脱氧核糖核酸 RNA为核糖核酸。区别是5碳糖第二...
基于原子核自旋运动的核磁共振(Nuclear Magnetic Resonance, NMR)是指在外磁场作用下磁矩不为零的原子核，自身的自旋能级发生塞曼分裂，共振吸收某一频率的射频辐射的过程。对于大量微观粒子组成的宏观物质，无外磁场作用时核自旋的方向是杂乱无章的。当有外磁场作用于这些微观粒子时，系统的磁化强度矢量开始从 Copyright...
Optimization of CPMG sequences to measure NMR transverse relaxation time T2 in borehole applications. Geosci. Instrum. Method Data Syst. 1, 197-208.M. Ronczka, M. Muller-Petke, Optimization of CPMG sequences to measure NMR transverse relaxation time T-2 in borehole applications, Geosci. ...
这篇我们讲讲核磁弛豫三兄弟中最没有存在感的T2※弛豫,进而分析为什么T2弛豫要用CPMG序列。 核磁共振序列比较抽象,确实很难理解。相信有一些同学做了很多次T2实验,至今还不明白CPMG序列,以及为什么要用CPMG序列,如果你也存在这样的疑惑,非常建议您花5分钟的时间,阅读接下来的1500字。
AbstractIn NMR well-logging, the measurement apparatus typically consists of a permanent magnet which is inserted into a bore, and the sample is the rock surrounding the borehole. When compared to the conditions of standard NMR experiments, this application is thus challenged by relatively weak and...
【英语版】国际标准 ISO 16756:2024 EN 牛奶和奶制品—应用Carr-Purcell-Meiboom-Gill(CPMG)脉冲时域核磁共振(TD-NMR)光谱法测定脂肪的指导建议 Milk and milk products — Guidance for the application of Carr-Purcell-Meiboom-Gill (CPMG) pulsed time-domain nuclear magnetic resonance (TD-NMR) spectros.pdf...
标准CPMG-T2数据集-仿真数据(双峰,T2=5.8、90ms) 数据源:NMR_Forward_Inversion仿真软件 0 构造谱 1 高信噪比 模拟回波采集 T2反演谱 2 中信噪比 模拟回波采集 T2反演谱 3 低信噪比 模拟回波采集 T2反演谱
Detection and quantification of low molecular weight components in polymeric samples via NMR spectroscopy can be difficult due to overlapping signal caused by line broadening characteristics of polymers. A way of overcoming this problem could be the exploitation of the difference in relaxation between ...
CPMG relaxation dispersion NMR experiments have emerged as a powerful method to characterize protein minor states that are in exchange with a visible dominant conformation, and have lifetimes between ~0.5 and 5 milliseconds (ms) and populations greater than 0.5%. The structure of the minor state ca...