synthetic and mineral oil. low saturation vapour pressure , anti-oxidation, wear-resistance , corrosion-resistance, anti-radiation etc, small adhesion and long life etc.
以及它们的低饱和蒸汽压、抗氧化、抗磨、抗腐蚀、抗放射性、粘度小、寿命长等特性。
percentage ration of the actual vapour pressure in the air to the saturation vapour pressure with respect to water at the same temperature and pressure.