Some memories of Prof. Chi Yuan:
I first met Prof. Yuan in ASIAA when I was a second year undergraduate student in National Taiwan University. I did not have too many interactions with Prof. Yuan until a year later when I received formal astrophysics class from him. This is a full year class, which covers a wide range of topics. In this class, he spent a lot of time on his favorate topic --- spiral density wave theory, which involves a lot of math and is quite difficult for an undergrad. student. Fortunately, Prof. Yuan is a "nice" professor and the problems in the exams were not very tricky, so I was able to handle the class relatively well.
The best time I had with Prof. Yuan is when we traveled to Hualien together during the summer in 2003. He had old friends from Russia, and he wanted me to be a tour guide to Hualien since I was born there and is familiar with the place. For some crazy reason I don't remember now, I decided to bring these "old" people to reach the eatern peak of the Ho-Huan mountain (located in the famous Taroko National Park), which is 3417 meters (11203 foot) above the sea level. Ironically, although I was the tour guide, I was not the person who lead the team to reach the peak. His friend, his friend's wife, and I were tired and could not move very fast (the air is thiner). However, Prof. Yuan was still very energetic and can move fast. At certain points, he even needed to stop and wait for us! In the end, Prof. Yuan lead his old friends and a 23-year-old "young" man to reach the peak, and we had a great time!
The deepest memory of Prof. Yuan I have is his kindness toward students. I believe that in his eye, there is no stupid student. As long as a student is willing to learn, he is willing to teach and help. In my own case, I still remember, one day after class, probably because he knew my eager to study astronomy in graduate school in the US, he voluntarily told me that he is willing to write recommendation letter for me. While I highly repected him and my grade was just ok, I really felt gratitude and honor for such an offer. Although I did not request the recommendation letter from him in the end, his kindness always remain in my mind.
I think that it is our responsibility to pass this seed of kindness to the next generations of students. Although Prof. Yuan has passed away, as long as the seed of kindness remains, his virtue, his spirit will remain.