The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
%\cite{Xu:IPAC2016-WEOAA02} \bibitem{Xu:IPAC2016-WEOAA02} G. Xu, J. Chen, Z. Duan, and J. Qiu, \textquotedblleft{On-axis Beam Accumulation Enabled by Phase Adjustment of a Double-frequency RF System for Diffraction-limited Storage Rings}\textquotedblright, % in \emph{Proc. IPAC2016}, pp. 2032--2035, % in \emph{Proc. IPAC2016}, Busan, Korea, May 2016, paper WEOAA02, pp. 2032--2035, in \emph{Proc. 7th Int. Particle Accelerator Conf. (IPAC'16)}, Busan, Korea, May 2016, paper WEOAA02, pp. 2032--2035, % ISBN: 978-3-95450-147-2, \url{http://jacow.org/ipac2016/papers/weoaa02.pdf}, \url{doi:10.18429/JACoW-IPAC2016-WEOAA02}, 2016.