In the past, urban sanitation work was carried out by the public institutions in the state-owned system. Therefore, it cannot be called an industry at that time. With the deepening of marketization, the rise of specialized companies, the participation of excellent companies, and the …

Sina science and technology as long as careful observation, even in his death 2500 years later, you can still identify the footprints of his toe bottom. This is the body of a 14-year-old b…

Over the past decade, the solar water heater industry has developed rapidly, technology has matured. With the continuous appearance of high-rise buildings, ordinary one-piece vacuum tube solar water heater can no longer meet the requirements of solar water heater and building integration. …