90°脉宽的测定

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90° 脉冲宽度的矫正

90度脉冲宽度是由pw（宽度）和tpwr (发射机功率). 许多实验(特别是 2D实验) 需要准确的pw和tpw 的值. 所以定期检测90度脉冲宽度是非常必要的。

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Determining the ¹H 90° pulse width of the transmitter

1. Using your sample, collect a 1-pulse experiment, with pw equal to the 90° pulse width (pw90) and tpwr listed at the spectrometer. Type lb=0.5, set all other apodization functions to 'n', and process and phase the spectrum.
2. Type gain='y'
3. Type array then answer the prompts:
   1. Parameter to be arrayed: pw
   2. Number of steps in array: 4
   3. Starting value: (whatever pw90 is)
   4. Array increment: (whatever pw90 is)
4. Type ai ga and hit Enter
5. Type vp=80 vs=90 dssh
6. Determine if your value of the last pw is less than or greater than the 360° pulse width. You should see 4 spectra, the first one (90°) should point up, the second (180°) should be weak and dispersive (but possible slightly positive), the third (270°) should point down, and the last (360°) should again be weak and dispersive.  If the last one is still pointing down, your pw is too short, if it's pointing up, pw was too long.  Repeat steps 3, 4, and 5 until you are satisfied that you have determined the correct 360° pulse width.
7. Set pw to the 90° pulse width (1/4 of the 360° pulse width), type gain='n', and type ga. Verify that the phase of the spectrum can be adjusted correctly. If it cannot, start again at step 1.
   

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[此贴子已经被作者于2006-11-16 18:17:31编辑过]

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aspect

哪位有Bruker的  90°脉宽的测定？

submarine

1) atma 1H (Tunning+Maching) 5 v& j1 v- x' U7 U2) take a normal 1H spectrum with ns = 1; rga , etc : y2 }) l1 {1 i) r3) ft and phase it manually or just type apk 4) change pulprog zg30 to zg, using eda or select AcquPars icon / g8 e- x; c. [8 c( N: W. S+ O4 {5) change the p1 value to (p1 plus or minus 0.1 or 0.2 and so on) *4 / r# t# b6 m7 T7 ~5 S+ b6) check the p1 value, (it should be below 50u) ->type p1 return 7) zg again 7 B8 A9 D, H4 ^8) fp (this moment do not phase the spectrum anyway) - z3 G4 v0 U3 W2 e0 w# K$ M% H9) if the peaks appear mostly positive, reduce p1 value, and do step 7 and step 8 again 9 A/ ?5 u; s, |5 s/ h% ^. q( a10) if the peaks appear mostly negative, increase p1 value, do step 7 and step 8 again 11) while the intensity of the peaks appear mostly half positive and half negative, then it is the correct 90 pulse width *4 12) divide p1 value by 4 (this is the value which can be used in 2D expts for 1H 90 pulse hard pulse). - ~" Q# s5 l4 x7 m" z+ W13) change pulprog = zg30, ns = 16, p1 =(90pw) start the 1H experiment( Reset to Normal Mode ) Note :If no appropriate value is find at all, start the small value of p1=3u,with pulprog = zg again , then check that the phase is positive or not. It should be positive, else, try again from step 5 to step 12.

huyichen

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