Acquisition delayed

Figure 3.17. Pictorial representation of the complete pulse-acquisition-delay sequence (including parameters tp, hcq, and tw), repeated twice.

The different information obtainable from a chemical-shift weight and a relaxation-parameter image is illusiraled in Fig. 8.3,2 Pra3] In covulcanization of different rubber sheets, for example, sheets from SBR and NR, an interface may arise depending on the materials and the conditions of vulcanization (Fig. 8.3.2(a)). A sufficiently long acquisition delay t without chemical-shift refocusing introduces the chemical-shift... 

Figure 3.39. First-order (frequency dependent) phase errors arise from a dephasing of magnetisation vectors during the pre-acquisition delay which follows the excitation pulse. When data collection begins, vectors with different frequencies have developed a significant phase difference which varies across the spectrum.

The simple one-pulse experiment is shown below, the delay dl is called the relaxation delay and it ensures that in a multi-scan experiment the spin system has returned to equilibrium before the next pulse (see Check it 5.2.1.5). The delay dlO is not normally part of the ordinary sequence scheme and represents the pre-acquisition delay (Bruker nomenclature del, de2). This delay is automatically inserted to enable time for switching between transmit and receive mode to minimize pulse breakthrough. For further aspects the reader is referred to section S.2.3.4 Check its 3.2.3.4 and 3.2.3.6). 

Caoili EM, Inampudi P, Cohan RH et al (2005b) Optimization of multi-detector row CT urography effect of compression, saline administration, and prolongation of acquisition delay. Radiology 235 116-123 Catalano C, Pavone P, Laghi A et al (1999) MR pyelography and conventional MR imaging in urinary tract obstruction. Acta Radiol 40 198-202... 

Radial 8-arm maze acquisition Delay Alfano and Petit, 1981... 

Figure 6.4 presents examples of the A1 plasma emission spectra measured in backward direction, such as regular plasma emission (Fig. 6.4a), plasma plume emission pumped at 257.5 nm (Fig. 6.4b) and plasma plume emission placed in optical resonator (Fig. 6.4c). Solid curve is regular LIBS, dash curves presents the excitation at 257.5 nm and dot curve presents the excitation at 256.8. All results are measured 4 ps after plasma plume creation, 0 ns acquisition delay and with gate width of 1 ps. Plasma emission lines Full Width at Half Maxima (FWHM) is about...

Overhauser enhancements can always be suppressed, if required, through use of an inverse gating sequence with delays >10 X Tj s between acquisitions (29,30). Unfortunately, this process increases the spectrometer operating time ca. 4 times, and more time still is needed for determination of the longest relaxation time, Tp of the different tritons in the sample, if the acquisition delay is to be set correctly. The suppression procedure is therefore too costly in time to justify routine use (21,27). 

Fig. 8. Comparison of the P-NMR spectra (121.47 MHz) of a dry powder of dipalmitoyl-phosphatidylcholine (DPPC) acquired with (A) a single 90 pulse and H decoupling (B) a single 90 pulse and no H decoupling and (C) a Hahn echo and H decoupling, where 0 =9O , 62 = 180 , and the pulse spacing was 60 /is. The 90 pulse width was 7 /is and the acquisition delay for the single pulse spectra was 12 /is. From Ranee and Byrd (1983).

Fig. 15. Proton-decoupled P-NMR spectra (at 60.7 MHz) of pure DMPC and of protein-or cholesterol-containing complexes at 32 2 C in excess water. (A) Pure DMPC. (B) DMPC sample containing 80 wt % cytochrome c oxidase. (Q DMPC sample containing — 70 wt % sarcoplasmic reticulum ATPase. (D) DMPC sample containing 70 wt % human lipophilin (N2 protein). (E) DMPC system containing 25 wt % cholesterol. Spectral conditions were typically a 50-kHz spectral width, 1-s recycle time, 4-/is 90° pulse, SO data-acquisition delay time, 8192 data points, and 50-Hz line broadening. The number of scans varied between 4000 and 16,000. Sample volume was 250 /tl. Gated proton decoupling with pulses of50-100 ms, 40 W, were used. From Rajan et al. (1981).

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