The brand of imported aerial vehicles is service-centered. What they do is also t.......

[Electromechanical Online News] With the country's efforts to increase energy conservation and environmental protection, the increasing price of electricity and the global ban on the sale of incandescent lamps have driven the demand for LED lighting to gradually increase. China's L.......

Abstract: In order to improve the quality of medicines such as powder injections and biological preparations packed in vials during the shelf life period, companies ofte.......

Hard white metal, density of 12.30 g cm. The temperature of 2310 ° C, the boiling point of 3900 ° C. Valence prices 2, 3, 4 and 8. The first ionization energy is 7.37 electron volts. The chemical properties are very stable. Whe.......