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第22讲-医学核磁共振和化学核磁共振Lecture 22 - Medical MRI and Chemical NMR |
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| 课程网址: | http://videolectures.net/yalespan125bs2011_mcbride_lec22/ |
| 主讲教师: | J. Michael McBride |
| 开课单位: | 耶鲁大学 |
| 开课时间: | 2014-08-19 |
| 课程语种: | 英语 |
| 中文简介: |  |
| 课程简介: | Magnetic resonance imaging (MRI) requires gradients in the applied magnetic field, while chemical nuclear magnetic resonance (NMR) requires a highly uniform field. When protons in different parts of the body can be driven to broadcast different frequencies, tomography allows reconstructing a three-dimensional image showing water location. Dependence of the signal intensity on relaxation allows BOLD functional MRI that shows brain activity. When the applied magnetic field is sufficiently uniform, chemical NMR spectra differentiate proton signals according to local field variations within molecules. Modern research in a chemical laboratory like Yale's depends on the availability of many magnetic resonance spectrometers. Peak integrals show the relative number of protons in different molecular environments, while peak frequencies or "chemical shifts" show the bonding environment of groups of protons. Often downfield (deshielded) or upfield (shielded) shifts are correlated with local electron density. |
| 关 键 词: | 磁共振成像; 化学核磁共振; 层析成像 |
| 课程来源: | 视频讲座网 |
| 数据采集: | 2021-11-12：zkj |
| 最后编审: | 2021-11-12：zkj |
| 阅读次数: | 222 |