Mechanical and electrical products technology research and development, technical consulting, technical services; Graphene products, heating equipment manufacturing, design, installation, sales; Mining machinery equipment and accessories technology research and development, manufacturing, sales; Import and export of goods or technologies (except those prohibited by the state or involving administrative examination and approval). Sales of optoelectronic devices; Electronic components manufacturing; Optoelectronic device manufacturing; Research and development of special electronic materials; Semiconductor device special equipment manufacturing; Lighting fixture manufacturing; Lighting appliances sales; Sales of wearable intelligent devices; Wearable intelligent device manufacturing; Digital video monitoring system manufacturing; Digital video monitoring system sales; The second category of medical device sales; Retail of medical masks; Wholesale of medical masks; Daily mask (non-medical) production; Daily mask (non-medical) sales (items subject to approval according to law can only be carried out after approval by relevant departments)