(a) general projects: technical services, technical development, technical advice, exchange of technology, technology transfer, technical promotion; construction of noise-reducing equipment; reduction of noise-reducing equipment; sale of integrated circuits; sale of specialized electrical equipment; sale of specialized electrical equipment; sale of metal structures; sale of metal structures; development of metal products; engineering and technological research and experimental development; development of machinery equipment; development of artificial intelligent applications; integration of artificial intelligent industrial applications; rental of construction machinery and equipment; installation of general mechanical equipment; sale of construction metal spare parts; sale of machinery and spare parts; sale of new energy sources; acquisition of specialized equipment; export and import of metal services; acquisition and export of equipment other than mechanical engineering services; maintenance of specialized equipment for the design of industrial engineering equipment; maintenance of specialized equipment