Xu Tianchen

Xu Tianchen is not mentioned in any of the provided news articles. Therefore, it is impossible to provide a description, summary, or any information about them based on the given context. The articles focus on China's economic policies related to commodity trading, US-China trade talks, and tariff strategies. They discuss topics such as the suspension of trading in commodity funds, negotiations on AI chips and farm products, and China's approach to securing resources through low import duties. These topics are relevant to understanding the current economic and political dynamics between China and the US, but they do not provide any information about an individual named Xu Tianchen.