Centre-burst

In an FT-IR spectrometer, the source is, of course, a broadband (polychromatic, continuum) source, thus the interferogram recorded can be considered as a summation of all the cosine functions of the individual wavelengths present in the souree these will only all be in phase at the position of ZPD, and give rise to a strong interferogram centre-burst (see Figures 2.3(b) and 2.4). The... 

In the Smith-Hieftje system, the lamp power is subjected to short pulses of high current.17 This causes momentary bursts of high atom concentration in the hollow cathode. The emission line profile is broadened as an atom cloud forms just outside the cathode, which causes absorption at the centre of the emitted line profile, as shown in Figure 7. Effectively the single narrow emission line is split into a pair of lines immediately adjacent to the original line centre. Thus, in the normal mode, atomic and molecular absorption are measured, but in the pulsed mode, only molecular absorbance is monitored. The difference between the two signals provides a corrected atomic absorbance signal. 

His raised vobe merged into a howl of feedback. As he sat back the hal burst into conmotion Many of the people in the chairs came to their feet, applauding and shouting approval As the cameras flashed and journalists shouted questions, Scarsdale sat centre stage and surveyed his work. For a moment he looked right at me. His eyes burned wkh fervour. And triunph, I realized. 

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