Multipulse experiments composition

However, for nuclei that display a much greater frequency dispersion, such as C or F, this is often not the case, and resonance distortion and/or attenuation can occur, and spurious signals may arise in multipulse experiments as a result. One approach to overcoming these limitations is the use of clusters of pulses known as composite-pulses which aim to compensate for these (and other) defects see Chapter 9. 

In the three-zone TAP reactor, it is difficult to maintain a uniform profile of the catalyst surface composition because of the gas concentration gradient, which is the driving force for the diffusion transport in the reactor. This nonuniformity of the catalyst surface composition becomes significant particularly in multipulse experiments. 

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