National Astronomical Observatories;
Chinese Academy of Sciences;
Beijing 100101;
China;
School of Astronomy and Space Sciences;
University of Chinese Academy of Sciences;
Beijing 100049;
China;
CAS Key Laboratory for Computational Astrophysics;
National Astronomical Observatories;
Chinese Academy of Sciences;
Beijing 100101;
China;
galaxies:binary; quasars:general; methods:n-body simulations;