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| Result: Searchterm 'Population'
found in 2 messages |
| Result Pages: [1] |
More Results:  Database (5) News Service (7) Resources (1) |
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Herbert Müller
Thu. 5 May.22,
01:33
[Reply (11 of 12) to:
'90 excitation pulse vs 180 inversion pulse'
started by: 'Bjorn Redfors'
on Sat. 27 Jun.09]
 Category:
Basics and Physics
|
| 90 excitation pulse vs 180 inversion pulse |
Hello,
I dont know if anyone has, for him/herself, answered this question. I know it is an old thread. But this is the question which also botheres me the most in NMR/MRI.
I refer now to a picture, which is illustrated in the book from Tim Claridge (High resolution NMR techniques).
Here, a RF pulse (lets say a 90 degree pulse) is said to have two effects on the initial z-magnetisation. First, it allows energy transfer between the two Zeeman-states in a way, that i equalizes the population difference between them. So there is no z- magnetisation anymore after 90 degree pulse. Th esecond effect is, that it induces phase-coherence. And this phase coherence is then responsible for the x-magnetisation, which is measured.
And now I have the same question. Why is this phase coherence lost (or is it not?), when applying an initial 180-degree pulse. Understandable for me is, why the population difference in z is reversed, but I dont understand, why there is no xy magnetisation anymore.
Maybe some of you have figured out the answer in the meantime?
Greetings
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Katelin Lyons
Fri. 27 May.11,
09:51
[Reply (1 of 2) to:
'Career as a Physician'
started by: 'Aaliah Thomas'
on Fri. 27 May.11]
Category:
General
|
| Career as a Physician |
Yes its true a physician's career is on high demand. With the growth in population and growth in medical sectors job opportunities are rising.To be a successful physician one should keep the following things in mind:
*Doctors must have a very strong grasp of math and science, chemistry and biology, and be able to analyze information and solve problems.
*Should exhibit excellent interpersonal skills in order to communicate effectively with patients and their families.
*Must be able to think quickly on their feet, and make critical decisions accurately and efficiently.
*If he aims to go into private practice and own a health care business, it would be helpful to have a basic understanding of business and accounting principles as well.
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