tag:blogger.com,1999:blog-3300702123878659843.post7904572538386214437..comments2024-03-26T05:25:50.831-04:00Comments on University of Ottawa NMR Facility Blog: Fast 90 Degree Pulse DeterminationGlenn Faceyhttp://www.blogger.com/profile/05146575170575279335noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-3300702123878659843.post-84461244751553112982016-02-16T09:19:30.919-05:002016-02-16T09:19:30.919-05:00AJAY,
I am a bit confused. Your question has noth...AJAY,<br />I am a bit confused. Your question has nothing to do with the fast determination of 90 degree pulses.<br />In answer to your question though .... with the typical 1H decoupler power levels used in solution-state NMR spectra, one can use a decoupler duty cycle of 100% safely.<br />GlennGlenn Faceyhttps://www.blogger.com/profile/05146575170575279335noreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-31854410709813686782016-02-16T06:24:05.313-05:002016-02-16T06:24:05.313-05:00Hello Glenn,
Could you tell me, if I am recording...Hello Glenn,<br /><br />Could you tell me, if I am recording proton-decoupled 13C spectra with typical 400ms AQ and D1 delay of 3.5 s and SW roughly 150ppm then what should be the duty cycle for a safe side?<br />Is there any limitation or relations between AQ and D1 time beyond which we can not go?AJAYhttps://www.blogger.com/profile/10330065734804621754noreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-25137410735840742572012-08-10T13:06:39.263-04:002012-08-10T13:06:39.263-04:00Anonymous,
Thank you for your questions. The dut...Anonymous,<br /><br />Thank you for your questions. The duty cycle is siply the fraction of time that the power is on for the duration of the data collection. There is no recycle or last delay. You can calculate the duty cycle for a single dwell period.<br /><br />GlennGlenn Faceyhttps://www.blogger.com/profile/05146575170575279335noreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-53709818351662290542012-08-10T12:52:30.344-04:002012-08-10T12:52:30.344-04:00Hello,
I just have a question about the duty cycl...Hello,<br /><br />I just have a question about the duty cycle. Can you explain exactly how that is calculated? Does it include the recycle or last delay? Or just the total time the pulses are emitted divided by the total time of the pulse and delays in between (without last delay)? This part was never clear to me.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-47422950222903103512010-03-24T13:29:49.361-04:002010-03-24T13:29:49.361-04:00Dear Mike,
Yes, this is just the real FT of the n...Dear Mike,<br /><br />Yes, this is just the real FT of the nutation sine wave, so the nutation frequency (taking the duty cycle into account) is one half the frequency between the peaks.<br /><br />The data in the figure were collected in analog mode. I noticed that the parameter HDUTY was incorrect and I worked out the true duty cycle by examining the acquisition loop in pulse sequence.<br /><br />GlennGlenn Faceyhttps://www.blogger.com/profile/05146575170575279335noreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-56082636835257890622010-03-24T13:14:36.106-04:002010-03-24T13:14:36.106-04:00Glenn - I have been thinking about the spectrum yo...Glenn - I have been thinking about the spectrum you get from this experiment. Correct me if I am wrong, but this is nothing more than the result of a "real" FT performed on a sine wave? In other words, one signal is an imnverted mirror image of the other?<br /><br />Also, do you know Bruker handles the duty cycle factor in this experiment, given that there would presumably be oversampling? Do you have to turn off digital acquisition and acquire in analogue?<br /><br />MikeAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-68160614715183918272010-03-17T12:20:34.695-04:002010-03-17T12:20:34.695-04:00In my opinion it's better to calibrate the pul...In my opinion it's better to calibrate the pulse powerlevels instead of the pulse length. We usually choose a desired 180° or 360° pulse length (6 and 12µs for our MAS and BB probes) and calibrate the powerlevels with Topspin's popt. This avoids you from writing "The 90° pulse length was 3.1µs on this day and 3.3µs on that day ..." in publications.<br /><br />FrankAnonymousnoreply@blogger.com