Channel number

Recursive procedures demand special attention to flow control and data structures. For instance, the flow control within the procedure must correctly handle an error, say missing file information or inconsistent data, that is discovered several iterations deep. Should the procedure break and return to the previous level only Should it force return to the level of the original invocation of the procedure Should it allow an interactive user a choice of supplying missing data, and if so, on any level of iteration If files are opened within the procedures, should they be closed when a recursive call is needed, or are new channel numbers to be requested, using up system resources ... 

Reactor type Wide fxed-bed reactor Pressure-drop channels number, width, depth 256 40 pm 20-25 pm... 

Reaction micro channel 70 pm 900 pm width depth length 61.4 mm Total number of reaction 32 8 channels number on platelet... 

The numbers are generic for our example and may be different for a real system, depending on the number of channels used in the MCA and the frequency chosen for the drive system. The channel numbers are usually a certain power of two like 512 = 2. The value of p IOO ps applies to a spectrometer with 512 channels operated at 20 Hz, which means a period time of 50 ms. The exact dwell time is obtained from the ratio of period time to the number of channels, which is 50 ms/ 512 = 97.7 ps per channel. 

Since the actual motion of the Mossbauer drive, as for any frequency transmission system, can show phase shifts relative to the reference signal, the ideal folding point (FP) of the raw data in terms of channel numbers may be displaced from the center at channel number (N — l)/2 (= 255.5 in the example seen earlier). The folding routine must take this into account. Phase shift and FP depend on the settings of the feedback loop in the drive control unit. Therefore, any change of the spectrometer velocity tuning requires the recording of a new calibration spectrum. 

Cahbration spectra must be measured at defined temperamres (ambient temperature for a-iron) because of the influence of second-order Doppler shift (see Sect. 4.2.1) for the standard absorber. After folding, the experimental spectrum should be simulated with Lorentzian lines to obtain the exact line positions in units of channel numbers which for calibration can be related to the hteramre values of the hyperfine splitting. As shown in Fig. 3.4, the velocity increment per channel, Ostep, is then obtained from the equation Ustep = D,(mm s )/D,(channel numbers). Different... 

The number of beatings in the output signal U t) can be recorded as a function of the channel number simultaneously to the Mossbauer spectrum (usually in a second part of the MCA memory). Accordingly, the number of beats stored in each channel per velocity sweep divided by the dwell time of the MCA channels yields the specific average velocity for each detection channel. 

For the visualization of the SCA discrimination window on the MCA screen, the TTL pulses, which map the coincidently incoming y-pulses, can be used to mark the range of channel numbers corresponding to the selected voltage range. The marks allow instantaneous control while setting the dials for lower and upper limits to the... 

If scattering curves are processed, the center is simply a channel number of the detector and centering is accomplished by subtracting this channel number from all other channel numbers. 

Cell-cycle phase distribution in an asynchronous population of CEM cells that were fixed in ethanol and stained with PI. The data, acquired with a BD FACScan, are presented as a histogram of PI fluorescence (a measure of DNA content), recorded in units of channel numbers. Analysis of the DNA frequency content histogram was performed with Modfit LT software... 

On the SELECT PROBES menu, choose TEMPERATURE. Enter 1 as the channel number. 

Choose SET UP PROBES from the MAIN MENU. Enter 1 as the number of probes. On the SELECT PROBES menu, choose CONDUCTIVITY. Enter 1 as the channel number. Then select USE STORED from the CALIBRATION menu and select H 0-2000 MICS from the CONDUCTIVITY menu. Make sure the switch on the box is set to the same value. 

Fig. 2. a. Intensity correlation of the scattered light from a PMMA sample in acetone recorded with a Malvern autocorrelator with 96 channels. At channel 80, a time shift device is introduced, by which the last 12 channels are shifted by 256 times the delay time of the first channel. These last channels were used for a determination of the base line, b Plot of In (G2 - 1 )m against the channel number (= time) for the same sample as in a. The deviation from the straight line arises from the internal flexibility of the PMMA chain... 

Determine mean fluorescence channel number in PE channel... 

Schmid, I., Schmid, P., and Giorgi, J V (1988) Conversion of logarithmic channel numbers into relative linear fluorescence intensity Cytometry 9, 533—538... 

A multichannel analyser is a type of digital x—y recorder in which x is the channel number (in this case the time after the excitation pulse) and y is the number of events which occur for the relevant channel (in this case the detection of a photon). For each excitation pulse the first emitted photon only is counted, but as the experiment is repeated many times with excitation pulse trains of thousands per second the whole kinetics of luminescence is reconstructed. 

Based on maximum mean channel number for a bead evaluated for highest ligand concentration and calibrated to molecular equivalent soluble fluorescence via Bang Labs calibration beads. 

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