The use and storage of liquid nitrogen tanks should pay attention to the following aspects: First, the inspection before use Before filling the liquid nitrogen tank, the liquid nitrogen tank should first check whether the outer casing is recessed or not, and whether the vacuum exhaust port is inta

Scientific name: Lophophorawillamsii Alias: 僧 僧 crown palm, fans commonly known as "black mullet", "fish." Family genus: Department of cactus, Yu Yu is a succulent plant. Origin: Wu Yu Yu originates in the desert regions of Central Mexico and Texas, USA. Morpholo

The purse seine from the Lake Yangcheng Lake in Bacheng, Kunshan, began in 1987. At that time, it was only nearly 1,000 acres. In 2000, it was developed to 25,000 acres. This article makes a summary of the technical points of raising crabs on lakes and purses of Yangcheng Lake in Bacheng. First,

The Tangle of Impact Factors——The Status of China's Science and Technology Investment and Sci-tech Journals According to: 10 years, it is not too short. In the past 10 years, the country has undergone tremendous changes, but there is a place, that is, China's scientific and t