The ultra-high vacuum liquid nitrogen circulation system of wuhan cryo -tech pte.,ltd. passed expert level acceptance on August 10, 2014 at the 55th Research Institute of China Electronics Technology Group Corporation (Nanjing). The molecular beam epitaxy MBE system belongs to a national high-tech project, which has very high requirements for liquid nitrogen storage, transportation, and pipeline vacuum. Our company adopts the technology of CHART company in the United States, which has reached the international advanced level.