Tunable monoenergy positron annihilation spectroscopy of polyethylene glycol thin films
Kuang Peng1, 2, Han Xiao-Long3, Cao Xing-Zhong1, Xia Rui1, Zhang Peng1, Wang Bao-Yi1, 2, †
       

(color online) Depth profile of S parameter for different PEG membranes.