Effect of substitution group on dielectric properties of 4H-pyrano [3, 2-c] quinoline derivatives thin films
Zeyada H M1, El-Taweel F M2, El-Nahass M M3, El-Shabaan M M1, †,
       

Frequency dependence of the density of charges N for (a) Ph-HPQ and (b) Ch-HPQ at various temperatures.