With Prof. A. M. Harned, Univ. of Minnessota USA (04/2008-06/2010)	With Prof. Zhao, Univ. of  San Antonio  Texas, USA(06/2010-05/2011)	With Prof. Stefan M Huber, TUM , Germany (06/2011-08/2013)
With Prof. B. Emmanuel, Institute of Curie, Paris (09/2013-08/2014)