V=1/P, or V=k(1/P)

V1P1=V2P2, or V2=V1P1/P2

V/T=k, or V1/T1=V2/T2

P/T=k, or P1/T1=P2/T2

PV/T=nR n是气体的摩尔数， R是玻尔兹曼通用气体常数

P1V1/T1=P2V2/T2

PB=PO2 PN2 PCO2 P trace gas

The sum of the partial pressures of the mixed gases is equal to the total pressure of the system. The partial pressure of any gas in a mixture is directly proportional to its percentage in the mixture.

Water vapor pressure does not follow Dalton's law and depends mainly on temperature. When calculating the partial pressure of a gas, it must be subtracted from the total pressure of the gas mixture

The same volume of gas contains the same number of molecules at the same pressure and temperature

Calculation of Gas Density and Specific Gravity

If the tube distal to the stenosis gradually expands as fluid flows through the stenosis, the pressure within the tube can return to the pre-constriction pressure. The gradual expansion of the pipe must have a divergence angle of less than 15 degrees

As the forward velocity of a gas (or liquid) through a pipe increases, the pressure on the side walls of the pipe decreases

Laminar flow - Poiseuille's law

Turbulence - Reynolds number NR

transition flow

The amount of gas passing through the semipermeable membrane (V̇ gas) per unit time is equal to The membrane surface area (a), the partial pressure gradient on both sides of the membrane (ΔP) and the solubility of the gas (S) are directly proportional; Inversely proportional to the square root of the gas molecular mass and the film thickness (T).

The diffusivity of a gas is equal to its solubility divided by the square root of its molecular weight

At a constant temperature, the amount of gas dissolved in a unit volume of liquid Proportional to the product of the partial pressure of the gas and its solubility coefficient

When two gases are placed under the same temperature and pressure conditions, The diffusion rates of two gases are inversely proportional to the square root of their masses

If the mass of a gas is considered to be proportional to its density at constant temperature and pressure, then