Vacuum technology

In the middle and late 19th century, the success of the British industrial revolution promoted the development of productivity and scientific experiments, and also promoted the development of vacuum technology. In 1850 and 1865, a mercury column vacuum pump and a mercury drop vacuum pump were inve-----


Example 1: Household liquefied petroleum gas is liquefied by using a compressed gas volume at normal temperature, and stored in a steel tank, the same as a liquid lighter. Liquefied oxygen is collected according to the boiling point of the gas, and is separated after reaching various boiling point-----

Old house partially refurbished users tracking log

The simple renovation of the old house is nothing more than a brushed wall paint door. How long does it take? Netizen 1015055ailele recently refurbished the old house, detailed records of the renovation of the walls of the home, cabinets and door painting of the five-day process, we quickly came t-----