What do ppm, PEM, PCM and VCM mean in the coil?

VCM:VCM refers to vinyl chloride. Vinyl chloride, also known as vinyl chloride, is an important monomer in polymer chemical industry and can be made from ethylene or acetylene. It is a colorless and easily liquefied gas with a boiling point of-13.4℃, a critical temperature of 142℃ and a critical pressure of 5.22MPa. Vinyl chloride is a toxic substance, and liver cancer is related to long-term inhalation and contact with vinyl chloride.

PCM:PCM is the abbreviation of centriole, which means centriole.

PEM:PEM has many meanings. 1. The mainland of ghosts and gods is a large-scale multiplayer online role-playing game launched by Perfect Space Company. Second, the patented engineering materials of PECO company in the United States; Three, cold pier rivet nuts, etc.

PPM:ppm is the abbreviation of English part per million, which means parts per million. On different occasions, it is often used to express the accuracy of a device's DC parameters when combined with some physical quantities.

Extended data ppm is volume specific concentration: one in a million.

Ppm is the expression of solution concentration (solute mass fraction). 1L aqueous solution contains 1mg solute, g/m3 or mg/l.

For gas: the volume of pollutants contained in one million volumes of air.

China's laws and regulations, especially the environmental protection department, require gas concentration to be expressed in mass concentration units (such as mg/m3), and China's national standards and specifications are also expressed in mass concentration units (such as mg/m3). The conversion formula between ppm and mg/m3 is: mg/m3 = (m/22.4) × [273/(273+t) ]× [p/101325 ]× ppm, m gas molecular weight, t gas temperature, and p is pressure.

Baidu encyclopedia -PEM

Baidu encyclopedia -ppm

Baidu encyclopedia -VCM

Baidu encyclopedia -PCM