Abstract　

The color distribution of globular clusters is found to be bimodal, the bimodality changing with luminosity. Using color-magnitude diagrams of sets of clusters computed with orbit-averaged Monte Carlo simulations, it is suggested that different initial metallicites are main the reason for this observation. Groups of clusters with a bimodal color distribution are found to be older than a few Gyr, while young sets of clusters should not display such a bimodality.

We also show how to include the Post-Newtonian relativistic forces between black holes in our simulations, and discuss gravitational wave emission in pulsar timing and LISA bands. In the second part of the talk our new computational instruments are presented. Especially in our institutes in China, but also elsewhere, powerful supercomputers have been built using graphical processing units (GPU) for general purpose computing. China holds top ranks in the Top500 list of fastest supercomputers in the world with GPU clusters. We will discuss, how GPU and other 'green' supercomputing hardware is necessary to reach Exascale supercomputing.

Self intro：Dr. Dana Longcope is a Professor of Physics at Montana State University-Bozeman. He teaches Physics and conducts research, with both undergraduates and graduate students, in the area of Solar Physics. Dr. Longcope conducts theoretical research into the basic physics of magnetic fields in ionized plasmas and the application of these concepts to magnetic fields on the Sun. He has studied the storage and release of magnetic energy in the Sun's corona through a process known as reconnection. This kind of energy release is currently thought to occur in solar flares as well as smaller, less dramatic solar events called microflares and X-ray bright points. He has also studied the rise of slender strands of magnetic field from deep within the Sun up to the solar surface. The emergence of this rising flux leads to sunspots, and models of rise yields a better understanding of Sunspot characteristics. Dr. Longcope is a graduate of Cornell University (B.S. 1986, Ph.D. 1993), and did Post-Doctoral research at The Courant Institute of Mathematical Sciences (New York University) and the University of California, Berkeley. He arrived at Montana State University in 1996. Honors and awards include a Fellowship from the Miller Institute for Basic Research in Science (1993), a Faculty Early Career Development (CAREER) grant from the National Science Foundation (1997), the Presidential Early Career Award for Science and Engineering (2000), the Karen Harvey Prize from the Solar Physics Division of the American Astronomical Society (2003), and the Charles and Nora L. Wiley Award for Meritorious Research (2003) and the Cox Family Award for Creative Scholarship and Teaching (2006) both from Montana State University.