受物理机理与井眼环境的影响,核磁共振测井回波信号固有灵敏度低,因此噪声抑制成为贯穿仪器设计全过程的关键问题。以中海油田服务股份有限公司自主研发的核磁共振测井仪器EMRT(Elis Magnetic Resonance Tool)为例,基于原始回波信噪比...受物理机理与井眼环境的影响,核磁共振测井回波信号固有灵敏度低,因此噪声抑制成为贯穿仪器设计全过程的关键问题。以中海油田服务股份有限公司自主研发的核磁共振测井仪器EMRT(Elis Magnetic Resonance Tool)为例,基于原始回波信噪比的理论分析,分别从前置放大电路结构改进、采集模块有效分辨率提高和回波信号数字滤波算法设计等方面论述噪声抑制的方法及应用。EMRT在测井中的CHI值曲线表明:以上方法有效解决了核磁共振测井中的低灵敏度信号的检出问题。展开更多
The purpose of this study was to investigate the nuclear magnetic resonance （NMR） assignments of hydrolyzed products extracted from human blood plasma. The correlations between chemical, functional and structural pr...The purpose of this study was to investigate the nuclear magnetic resonance （NMR） assignments of hydrolyzed products extracted from human blood plasma. The correlations between chemical, functional and structural prop- erties of highly toxic pesticides were investigated using the PreADME analysis. We observed that toxic pesticides possessed higher molecular weight and, more hydrogen bond donors and acceptors when compared with less toxic pesticides. The occurrence of functional groups and structural properties was analyzed using ~H-NMR. The ~H- NMR spectra of the phosphomethoxy class of pesticides were characterized by methyl resonances at 3.7-3.9 ppm （8） with the coupling constants of 11-16 Hz （Je-cns）. In phosphoethoxy pesticides, the methyl resonance was about 1.4 ppm （8） with the coupling constant of 10 Hz （Je-cH2） and the methylene resonances was 4.2-4.4 ppm （8） with the coupling constant of 0.8 Hz （Jp-cH3）, respectively. Our study shows that the values of four parameters such as chemical shift, coupling constant, integration and relaxation time correlated with the concentration of toxic pesticides, and can be used to characterise the proton groups in the molecular structures of toxic pesticides.展开更多
基金The National Key Basic Research Program of China(2013CB910203)the National Natural Science Foundation of China(31270760)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB08030102)the Specialized Research Fund for the Doctoral Program of Higher Education(20113402120013)
文摘受物理机理与井眼环境的影响,核磁共振测井回波信号固有灵敏度低,因此噪声抑制成为贯穿仪器设计全过程的关键问题。以中海油田服务股份有限公司自主研发的核磁共振测井仪器EMRT(Elis Magnetic Resonance Tool)为例,基于原始回波信噪比的理论分析,分别从前置放大电路结构改进、采集模块有效分辨率提高和回波信号数字滤波算法设计等方面论述噪声抑制的方法及应用。EMRT在测井中的CHI值曲线表明:以上方法有效解决了核磁共振测井中的低灵敏度信号的检出问题。
文摘The purpose of this study was to investigate the nuclear magnetic resonance （NMR） assignments of hydrolyzed products extracted from human blood plasma. The correlations between chemical, functional and structural prop- erties of highly toxic pesticides were investigated using the PreADME analysis. We observed that toxic pesticides possessed higher molecular weight and, more hydrogen bond donors and acceptors when compared with less toxic pesticides. The occurrence of functional groups and structural properties was analyzed using ~H-NMR. The ~H- NMR spectra of the phosphomethoxy class of pesticides were characterized by methyl resonances at 3.7-3.9 ppm （8） with the coupling constants of 11-16 Hz （Je-cns）. In phosphoethoxy pesticides, the methyl resonance was about 1.4 ppm （8） with the coupling constant of 10 Hz （Je-cH2） and the methylene resonances was 4.2-4.4 ppm （8） with the coupling constant of 0.8 Hz （Jp-cH3）, respectively. Our study shows that the values of four parameters such as chemical shift, coupling constant, integration and relaxation time correlated with the concentration of toxic pesticides, and can be used to characterise the proton groups in the molecular structures of toxic pesticides.
