Beijing/Hong Kong CNN — The world is big enough for both the United States and China to thrive, US Treasury Secretary Janet Yellen said Sunday as she wrapped up a visit to Beijing aimed at stablizing the relationship between the world’s two largest economies. Yellen said she had “direct, substantive, and productive” talks with China’s new economic leadership, including Premier Li Qiang and Pan Gongsheng, the newly appointed Communist Party chief of China’s central bank. “No one visit will solve our challenges overnight. But I expect that this trip will help build a resilient and productive channel of communication,” Yellen…