Group 1 - The company, Aerospace Changfeng (600855.SH), has announced a stock price fluctuation notice, clarifying its main business segments which include military electronics, public safety, and high-end medical equipment [1] - The company has not engaged in brain-computer interface related businesses or commercial aerospace activities [1] - Investors are advised to be cautious and aware of investment risks [1]

Group 1 - The core business of the company is focused on vehicle communication terminals and public safety products, explicitly stating that it does not involve products in the optical communication field [2]