Stanley Osher (UCLA): Xudong's Ph.D advisor, NAS member.
(刘旭东博士的博士导师,美国科学院院士)

''The mathematical community suffered a huge loss with the untimely passing of Xudong Liu. Our world is colder and darker today with the absence of one of its most lovable and talented members.However, his work on WENO, central and positive schemes and on interface problems will live on. His unique positive and charming personality will also live on. We will always miss him.
Xudong Liu made many contributions to scientific computation and other areas of applied mathematics. He will always be remembered for his 1994 paper in which the notion of weighted essentially non-oscillatory schemes was introduced. This paper has 227 links on Google and there are almost 600 links to "weighted essentially .." This idea allows one to improve the performance of essentially non-oscillatory schemes for shock capturing dramatically. WENO schemes are the method of choice for many researchers in a wide variety of areas. In addition, he made state-of-the-art contributions to: positive schemes, central schemes, and introduced convex ENO methods. These are all part of many users' toolbox. He also helped develop the ghost fluid method, extending it to viscous flows. This is also widely used, e.g., in computer graphics. His work was not only innovative, but also rigorous. He has some very nice papers involving rates of convergence for these and related methods. He was also a fine educator, turning out excellent Phd students. He was a leader in his field and now he is the WENO angel.''