Prof.Ballauff and Prof. Yan Lu from  Helmholtz-Zentrum Berlin für Materialien  und Energie, Germany visited our group on June. 16th and gave lectures titled "Catalysis by metallic and oxidic nanoparticles in aqueous solutions: Model Reactions" and "Thermosensitive Microgels as "active" nanoreactors for tuning the catalytic activity of metal/metal oxide nanoparticles", respectively.