The seed management stations in various places bear the important task of ensuring the quality and safety of seeds. The important work content is to ensure the safety of agricultural production through seed testing and to enable farmers to use “relieving seedsâ€. And standing
A. Principle: The valve can be installed in any position in the container, when the liquid in the container is increased and the liquid level is raised, when the first ball is fully buoyant, the permanent magnet can not be driven to control the valve to be closed due to the insufficient buoyancy. Wh
LED outdoor advertising display investment prospects can be expected. A few days ago, an advertising market research institute revealed that by 2015, China's outdoor LED display screen advertising market will exceed 2.7 billion yuan. The rapid expansion of LED outdoor advertising will further sq
Sun Jisong, chief engineer of the Beijing Meteorological Observatory, said that from around 15 o'clock on the 23rd, convective precipitation clouds began to affect the direction of Yanqing in the northwest of Beijing, and moved from northwest to southeast. Before and after 16:00, they