BEIJING: Beijing said on Tuesday (Dec 3) it would restrict exports to the United States of some key components in making semiconductors after Washington announced curbs targeting China's ability to make advanced chips. Among the materials banned from export are metals gallium, antimony and germanium, China's commerce ministry said in a statement that cited "national security" concerns. Exports of graphite, another key component, will also be subject to "stricter reviews of end-users and end-