Regenerative synthesis of copper nanoparticles by photoirradiation N. Nishida, A. Miyashita, N. Hashimoto, H. Murayama and H. Tanaka Eur. Phys. J. D, 63 2 (2011) 307-310 Published online: 27 April 2011 DOI: 10.1140/epjd/e2011-10515-8