With Prof. Ya-xiang Yuan on ISMP1997 in Lausanne, Switzerland
With Prof. Yinyu Ye (Middle) and Prof. Ya-xiang Yuan (Left) in Beijing (1998)
With Roger Fletcher in Dundee (2002)
With Mr. and Mrs. Schittkowski in Bayreuther (2004)
Playing bridge with Prof. M.J.D. Powell and Prof. Ya-xiang Yuan in Greece (2012)
With Prof. Lin Xiao (third from left), Prof. Shuzhong Zhang (fourth from left), Prof. Xiaojun Chen (sixth from left), Prof. Xin Liu (seventh from left) on ICCOPT2016 in Tokyo
With Florian Jarre in Fragrance Hill, Beijing (2017)
With Prof. Phillipe L. Toint in Brazil (2018)
With Prof. Oleg Burdakov (Left) and Prof. Ya-xiang Yuan (Middle) in Beijing (2019)
With Prof. Christian A. Shoemaker in Berlin (2019)