Scanning time sequence

Figure 2. Scanning time sequence for multiple integration time array detector system.

Fig. 3.7.2 DDIF (1) and reference (2) scan pulse sequences. The tipping angles of the pulses are marked as jt and jt/2. te and tD are two time periods. An echo signal is detected for DDIF and an FID for the reference sequence. Phase cycling of rf pulses is shown in Tables 3.7.1 and 3.7.2.

The tandem-in-time instruments are mostly ion-trapping devices, including ion trap and FT-ICR. They operate in a time sequence in the scan function to yield MS/MS data, mostly product ion spectra. No additional mass analyzer is required. In the case of an ion trap, the scan function begins with the isolation of ions of interest with ejection of all other ions from the ion trap, followed by (a) translational excitation of ions by applying a supplementary RF voltage to the trap and (b) mass analysis of the product ions using resonant ejection. 

Fig. 8. The rapid-scanning spectroscopic time courses for the reaction of 0.17 mM Co(II)-T6 with 100 mM phenol at pH 8.0 in the absence (A, C) and presence (B, D) of 100 mM chloride ion are shown. (A) Reaction in the absence of chloride ion. The time interval between scans is 8.54 ms for the first five spectra, followed by spectra at successively longer intervals afterward (see insets in C and D). The total acquisition time was 1.71 s for the 25 spectra collected only spectra numbers 1-5,7,10,12,15,18,21, and 25 are shown. (B) Reaction in the presence of 100 mM chloride ion. The timing sequence of the spectra is the same as that used in (A). For clarity, spectra 6, 8,10,12,14-16, 18-20, and 22-24 have been omitted. (C) The scaled, subtracted spectra, calculated from the second to the sixth spectrum of part A, correspond to the time-course for intermediate formation. The time course plotted in the inset shows the absorbance change at 560 nm for the complete set of scaled, subtracted spectra as a function of time. (D) Scaled, subtraction spectra numbers 2 to 6, as in part C, for the data part B, with chloride ion present. The inset plot also shows the time course at 560 nm obtained from the complete set. (Taken from Gross and Dunn (55) with permission.]...

For all real-time PCRs, it is a good idea to verify that all of the oligos (primers and probe) that will be used together in the same reaction will not form dimers, particularly at the 3 ends. The 3 complementarity can be checked by scanning the sequences manually. If you are using primer design software, the program itself may mn a check to make sure that the sequence choices it picks are not complementary to each other. 

When a chemist is searching manually his eye will scan a sequence of words which his brain will interpret. From his inherent knowledge of the subject he will from time to time recognise particular words or phrases as being relevant to the topic which interests him, but he will not usually... 

The potential and/or temperature controlled dissolution of the above order/ disorder transition is completely reversible in sulfuric acid solution. A representative time sequence, after application of a potential scan from 1 = 0.100 V to f = 0.500 V, is plotted in Fig. 41. Within a few seconds at f the 2,2 -BP molecules start to order. No preferential nucleation sites, which might correlate with defect... 

The most elegant solution is to take control action only when the analyser generates a new reading - effectively making the controller scan interval the same as the analyser sample interval. Most analysers have a read-now contact that can be brought into the DCS and used to initiate a control scan. However the analyser sample interval may not be constant. While some operate with a timed sequence, others will only move to the next step of the sequence once the previous one is complete. Steps like cooling or heating to a required temperature can vary in duration. We should not then apply a technique like PID which assumes a fixed sample interval. Techniques, such as Dahlin, readily permit the coefficients to be based on the actual sample interval. 

Crystallinity in ECH and ECH—EO finished products increases over time, and may be detected by x-ray analysis or differential scanning calorimetry. In synthesizing ECH—EO, the process is designed to maximize random monomer sequence and minimize crystallinity. The ECH—EO molecular ratio in these products ranges from approximately 3 1 to 1 1. 

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