Ultrasonic technology and application development; R&D and sales of cleaning equipment and instruments such as ultrasonic cleaning machines, plasma cleaning machines, hydrocarbon cleaning machines, laser cleaning machines, steam cleaning machines, high-pressure cleaning machines, dishwashers, environmental protection equipment, pure water equipment, water treatment equipment and accessories; domestic trade, import and export of goods and technology; technical services, technology development, technical consultation, technology exchange, technology transfer, technology promotion; sales of domestic waste treatment equipment; sales of household appliances.