【求助】国外大学的NMR题

2. In the statements listed below, choose all the correct ones.Choose at least one answer.

a. zg will 'zero' the memory buffer before starting acquisition.

b. zg will do 'DS' dummy scans followed by 'NS' actual scans.

c. zg will always perform multples of 4 scans.

d. zg will automatically change the temperature of sample to 298 K

3. The digits shown on the tune card of broad band probeheads should be chosen exactly to get the best tuning and
matching condition, no matter what sample you use. a.True b. False

4. What is the command you enter to shim the FID on the fly ?Choose one answer. a. go b. zd c. ze d. gs

5. Let us say, for a total number of NS scans in a 13C experiment, I get a signal to noise ratio (i.e. S/N ) of a peak to
be 5. I f I want to increase that peak's S/N value to 10, what are the options I have ?

a. Increase the number of scans NS by a factor of 4 b. Increase the molar concentration of sample by a factor of 2

c. Nothing can be done d. Increase the receiver gain by a factor of 2