I was shocked and extremely sad to learn about Weihan's passing. Weihan was the most cheerful colleague on the PhD. We shared an office during that time and he was indispensable to the friendly and fun office atmosphere that we all loved so much. It was always a pleasure to see him and chat. He was also an extremely resilient person and his positive attitude motivated and helped us many times. I will remember Weihan as a friend who lightened up any room he entered. My thoughts are with his family during this incredibly difficult time.