It is a happy day today. A sunny and cool morning of early summer, as if it were ready for my revisiting this dear campus after many years. New old friends, as if we were familiar with each other many many years ago. A valuable gift from Dr. Yuxian liu, the dissertation for her doctor degree: The Diffusion of Scientific Ideas in Time and Indicators for the Description of this Process. It will be my newest "pillow book". Dr. Liu introduced the main ideas of her dissertation, an amazing work with her whole-hearted dedication. 

Many thanks to professor Liu li, Dr. Liu Yuxian, and professor Jiang Jingsong, three outstanding scholars with deep thoughts, humorous personalities and quick thinking.