This proceedings volume, for the symposium in honor of Junwen Wang's 70th anniversary, is dedicated to his many important achievements in the field of accelerator physics.It includes the discussions of recent advances and challenging problems in the field of high gradient accelerating structure development.

This volume is a collection of the contributions to the 6th Annual Workshop on Polarized Positron held in China. It provides updated information on polarized positron source R&D efforts for future high energy linear colliders and other research activities related to the polarized positron studies.The topics covered include: positron beams for linear colliders, but not limited to it, with the main items listed below: