4. When vacuuming at high temperature, can the vacuum index be better after the cavity cools down? 5. What vacuum degree requirements can be reached before the temperature can be lowered? Why? 6. What are ionization inhalation, physical adsorption, and chemical adsorption? Which one can achieve better vacuum indicators?

1. How is vacuum measured? What are the methods? 2. Which experiments have extremely high requirements for ultimate vacuum? 3. What is the highest ultimate vacuum that universities or research institutions can achieve at present?

A complete temperature control system usually includes a temperature controller, a heater, a temperature sensor, cables, etc. The basic function of the temperature controller is to compare the actual temperature with the set value and output a signal to control the heater to maintain the set value temperature.

Hello everyone, previously we have mastered how to obtain low temperatures through six methods: phase change refrigeration, gas isenthalpic expansion refrigeration, adiabatic degassing refrigeration, eddy current refrigeration, temperature difference thermoelectric refrigeration and 3He-4He helium dilution refrigeration. This issue will show you how to obtain low temperatures through two methods: adiabatic demagnetization refrigeration and laser refrigeration.

In the previous issue, we introduced how to obtain low temperatures through phase change refrigeration, gas isenthalpic expansion refrigeration, and adiabatic degassing refrigeration. This issue will show you how to obtain low temperatures through three methods: eddy current refrigeration, temperature difference thermoelectric refrigeration, and 3He-4He helium dilution refrigeration.

Vacuum technology and cryogenic technology are both highly versatile sciences, and there is an inseparable relationship between them. There are many ways to obtain low temperatures, which can be roughly divided into two categories: physical methods and chemical methods. Most refrigeration methods are physical methods, among which gas adiabatic expansion refrigeration and phase change refrigeration are commonly used. There are also eddy current refrigeration, adiabatic degassing refrigeration

Vacuum technology and cryogenic technology are both very versatile sciences, and there is an inseparable relationship between them, mainly based on the interaction between gases and solid or liquid surfaces. At extremely low temperatures, almost all gases condense into solids because their saturated vapor pressure is very low, so a vacuum can be obtained.

During the epidemic, how to cut off the spread of the virus in public places is of paramount importance. In the first half, we introduced the advantages of ultraviolet lamp disinfection and the shortcomings of ultraviolet disinfection light sources on the market in epidemic prevention. In the second half, we will share some of the achievements made in the research and development of radio frequency focused plasma excitation technology.

During the epidemic, how to cut off the spread of the virus in public places is of utmost importance. In this section, we introduce the advantages of ultraviolet disinfection and the shortcomings of ultraviolet disinfection light sources currently on the market in epidemic prevention.

Sterilization and disinfection play an important role in public health. The new coronavirus epidemic has posed a great challenge to traditional sterilization and disinfection technologies, exposing the current prominent problem of the lack of sterilization and disinfection equipment that can quickly, thoroughly and batch process masks, protective clothing, etc.

The pressure of the gas in the vacuum system can be measured directly or indirectly by a vacuum gauge, that is, by directly measuring the force per unit area, or by deriving the pressure using the relationship between the gas pressure and some quantities to obtain the gas pressure value indirectly.

The ultra-high vacuum system (mainly metal sealing) mainly uses a cavity made of SS316 (or SS304) as the carrier, and is equipped with components with different functions (all of which are made of materials that meet the requirements of ultra-high vacuum low outgassing rate).