Manufacturing of electronic components; wholesale of electronic components; manufacturing of integrated circuits; sales of integrated circuits; sales of electronic products; sales of integrated circuit chips and products; sales of electrical equipment; sales of electrical signal equipment devices; sales of communication equipment; manufacturing of metal chains and other metal products; sales of metal chains and other metal products; sales of metal products; wholesale of computer software, hardware, and auxiliary equipment; retail of computer software, hardware, and auxiliary equipment; manufacturing of railway locomotive and rolling stock parts; sales of railway locomotive and rolling stock parts; manufacturing of urban rail transit equipment; sales of specialized equipment, key systems, and components for rail transit; research and development of mechanical equipment; sales of green composite materials for rail transit; sales of high-speed rail equipment and accessories; manufacturing of electrical signal equipment devices; sales of mechanical and electrical equipment; technical services, technical development, technical consulting, technical exchange, technology transfer, and technology promotion; manufacturing of communication equipment; sales of communication equipment; leasing of non-residential real estate; leasing of residential housing.