Correlation of heat treatment and the impurities accompanying Ag nanoparticles Asmaa A. H. El-Bassuony and H. K. Abdelsalam Eur. Phys. J. Plus, 135 1 (2020) 66 Published online: 13 January 2020 DOI: 10.1140/epjp/s13360-019-00025-y