Hu Jintao will play ping-pong and talk pandas and energy. The visit comes as strains over interpretations of history appear to be easing.
A third major group, whose materials work at relatively high temperatures, may lead to more efficient electric motors.
Readers write about outsiders' perceptions of China and how to better train the Iraqi Army.
When it comes to human rights, silence is not golden.
Joseph Needham put Chinese science on the world map.