送交者: outsider 于 March 18, 2003 17:57:34:
回答: pretty much 由 雪花 于 March 18, 2003 17:30:48:
Yes, at low temperature, you get quite good signal to noise ratio and there is not much thermal broadening - you can do precise NMR to identify the different resonance peaks. However, we can also do NMR at room temperature, like MRI imagine for medical purpose. In fact my colleagues are using NMR for subsurface oil/gas exploration at more than 150 C - thousands feet down in the earth. But of course we don't get as good signals and we have to limit NMR to simple applications.
No need to thank me. That's rudimentary stuff. There will be plenty of things that you can help me later.