Synergistic effect of thiourea derivatives and non-ionic surfactants on the inhibition of corrosion of carbon steel in acid environments

By using integral representations the perturbation expansion and the Bogoliubov inequality ain nonextensive Tsallis statistics are investigated in a unified way. This procedure extends the analysis performed recently by Lenzi et al. [Phys. Rev. Lett. 80, 218 (1998)] to the quantum (discrete spectra) case, for q < 1. An example is presented in order to illustrate the method.