Vacuum technical term
Jul 29, 2024
General term
1. Standard environmental conditions: temperature is 20℃, relative humidity is 65%, and atmospheric pressure is 101325Pa.
2. Standard state of gas: temperature is 0℃ and pressure is 101325Pa.
3. Pressure (pressure): When a gas molecule passes through a hypothetical plane, the momentum change rate along the normal direction of the plane, divided by the plane area or the normal component of the force that the gas molecule acts on the surface of the vessel, divided by the surface area.
4. Pascal (symbol: Pa): International system of unit pressure unit, 1 Pa=1N / m2。
5. Pressure pressure: the pressure of a certain component in the mixed gas.
6. Full pressure: the sum of the pressures of all the components in the mixed gas.
7. Vacuum: In a state of gas less than an atmospheric pressure in a specified space.
8. Vacuum degree: the thinning of the gas in vacuum is usually expressed by the pressure value
9. Gas: a material that is not constrained by the intermolecular interaction forces and can freely occupy any space.(Note: In vacuum technology, the term "gas" is not strictly applied to non-condensable gases and vapors.）
10. Non-coagulable gas: a gas above the critical temperature, that is, a gas that cannot be liquefiated by increasing the pressure alone.
11. Steam: a gas below the critical temperature, that is, a gas that simply increases the pressure to liquefied it.
12. Saturating steam pressure: the steam pressure of a substance whose vapor is in a phase equilibrium with its condensed phase at a given temperature.
13. Saturation: the ratio of the vapor pressure to its saturated vapor pressure.
14. Saturated steam: a pressure equal to its saturated vapor pressure at a given temperature.
15. Unsaturated steam: a steam whose pressure is less than its saturated steam pressure at a given temperature.
16. Number density of molecules (in m-3): At a certain moment, the number of molecules in a volume around a point in the gas is divided by the local product.
17. Average free range: the distance that a molecule collides with other gas molecules is called the free course. The average of a quite a number of different free ranges, called the average free range.
18. Collision rate: the average number of collisions experienced when a molecule (or other specified particle) moves relative to other gas molecules (or other prescribed particles) at a given time interval, divided by that time. This average number of collisions should be achieved with a sufficient number of molecules and a long enough time interval.
19. Volume collision rate: The average number of collisions between gas molecules at a given time interval is divided by the time and the volume of the space range. The time interval and volume should not be too small.
20. Gas volume: the product of the volume occupied by an ideal gas in equilibrium and its pressure. This value must indicate the gas temperature or the value when converted to 20℃.
(Note: Gas amount refers to 2 / 3 of the intrinsic energy (or potential energy) of the gas in the volume.
21. Diffusion of a gas: the movement of a gas in another medium due to a concentration gradient. The medium can be another gas (the diffusion in this case is called interdiffusion) or a condensed matter.
22. Diffusion system: the ratio of the value of the mass flow rate per unit area to the normal concentration gradient of that unit area.
23. Viscous flow: The average free path of the gas molecules is much smaller than the flow state of the small section size of the catheter *. Thus, the flow depends on the viscous nature of the gas, and the viscous flow can be laminar or retarded.
24. Viscous coefficient: the ratio of tangential force to velocity gradient per unit area in the direction of the airflow velocity gradient.
25. Poisaw flow: laminar viscous flow through the long catheter of the circular section.
26. Intermediate flow: the flow of gas through the conduit between laminar flow and molecular flow.
27. Molecular flow: The average free range of gas molecules is much larger than the flow state of the catheter section * * size.
28. Number: the ratio of the average free path of the gas molecule to the catheter diameter.
29. Molecular flow: the flow state of a gas flowing through thin-walled pores where the average free path of the molecules is much larger than the smaller pores.
30. Flow escape: the flow of gas caused by pressure differences through porous objects.
31. Heat flow escape: In the state of molecular flow, two connected containers cause gas flow due to different temperature. When the gas transmission reaches balance, the pressure gradient between the two containers occurs.
32. Molecular flow rate: In the case of a given time interval, the difference between the number of molecules crossing the surface in the given direction and the number of those molecules passing through the surface in the opposite direction, divided by that time.
33. Molecular flow rate density: Molecular flow rate divided by the surface area.
34. Mass flow rate: the mass of gas through a section at a given interval divided by that time.
35. Flow rate: the amount of gas passing through a certain section at a given time interval is divided by that time.
36. Volume flow rate: the volume of a gas passing through a certain section at a given temperature, pressure, and a given time interval, divided by that time.
37. The mole number of the gas passing through a given cross-section at a given time interval, divided by that time.
38. Maxwell velocity distribution: a velocity distribution determined by the Maxwell- -Boltzmann velocity distribution function. That is, the velocity distribution when the gas molecule is in equilibrium at a certain temperature and the distance to the device wall is greater than the average free path of the molecule.
39. Transmission odds: the irregular chance of molecules entering the catheter entry passing through the exit.
40. Molecular flow guide: The molecular flow guide through which a gas flows through two defined sections or holes of the tube is the ratio of the molecular flow rate and the difference between the average molecular number density between the two sections of the tube or on both sides of the hole.
41. Flow guide: under isothermal conditions, when the gas flows through the catheter or the hole, the flow rate and the average pressure difference between the two specified sections of the catheter or the two sides of the hole.
42. Intrinsic flow guide: The flow guide connecting the catheter (or holes) connecting these two containers over the Maxwell velocity distribution in the container. Under the molecular flow conditions, it is equal to the product of the inlet flow guide and the transmission probability.
43. Flow resistance: the reciprocal of the flow guide.
44. Adsorption: solid or liquid (adsorbent) on the gas or vapor (adsorbent) capture phenomenon.
45. Surface adsorption: gas or vapor (adsorbent) left on the surface of the solid or liquid (adsorbent) adsorption phenomenon.
46. Physical adsorption: the adsorption phenomenon due to physical action.
47. Chemical adsorption: the adsorption phenomenon due to chemistry.
48. Absorption: the diffusion of a gas or steam (adsorbent) into a solid or liquid (adsorbent).
49. Adaptation coefficient: the ratio of the average energy between a particle incident on a surface and the average energy actually exchanged on the surface to the average energy that the particle should exchange to achieve full thermal equilibrium conditions on the surface.
50. Injection rate: the number of molecules incident to the surface at a given time interval, divided by the time and the surface area.
51. Condensation rate: the number of molecules (or material mass or material mass) that condense on a certain surface area at a given time interval, divided by the time and the surface area.
52. Adhesion rate: the number of molecules adsorbed on the surface at a given time interval, divided by the time and the surface area.
53. The odds of adhesion: the ratio of the adhesion rate to the incidence rate.
54. Retention time: the average time that the molecule is constrained on the surface in the adsorbed state.
55. Migration: the movement of the molecules on the surface.
56. Desorption: the release of gas or vapor adsorbed by the material. The release can be either natural or accelerated by physical methods.
57. Gas: artificial desorption of gas from the material.
58. Bleeding the gas: the natural desorption of the gas from the material.
59. Unsuction or deflation or degas rate: the gas flow rate (or molecular flow rate) of desorption (or deflation or degas) from the material at a given time interval, divided by the time and the surface area.
60. Evaporation rate: The number of molecules (or material mass or material mass) that evaporate from a surface at a given time interval is divided by the time and the surface area.
61. Permeation: Gas passing through a solid barrier layer. The phenomenon includes the diffusion of a gas through a solid, and may also include other surface phenomena.
62. Permeability: Under the condition of stable flow, the flow rate of the gas through the barrier layer (such as the device wall) is divided by the amount of the pressure function on both sides of the barrier layer, which depends on the physical process involved in the actual penetration.
63. Omeation coefficient: the product of permeability and barrier thickness divided by the permeability surface area.
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