Nearly constant loss phenomenon

In 1991, A.S. Nowick and his coworkers discovered a new, second universality, which is ubiquitous in disordered ionic materials ( present in every plastic bag ) but becomes visible only at sufficiently low temperatures and/or high frequencies [30]. The phenomenon is also called Nearly Constant Loss (NCL) effect, since the dielectric loss function, e" oc ajv, appears to be virtually independent of both frequency and temperature, cf. Fig. 3. 

The search for a chemical understanding of the nature of the heat-inactivation phenomenon revealed that aspartoylimide residues were cleaved (16). This structure, which is formed during the polymerization reaction, is hydrolyzed most rapidly in basic solution (34, 37). Heating in buffer at neutrality causes loss of activity concomitant with hydrolysis of the imide structure. The cleavage has been monitored qualitatively by infrared analyses, and quantitatively by absorption near 200 m/i (Fig. 2), or by titration at constant pH. 

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