relative directional efficiency
相对方向效率

• polyvinylcyclohexene dioxide
• polyvinyl-fluoride
• polyvinylidene fluoride
• polyvinyl naphthalene
• ponderability
• pony axle
• poop
• poor focus
• poor light condition
• popular inversion area
• populated
• population
• population density
• population difference
• population distribution
• population hang-up
• population inversion
• population mean
• population of level
• population of parameter
• population ratio
• population risetime
• population threshold
• porcelain
• porcelain enamel