h.

名词 h.:

1. a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe
   同义词：hydrogen, H, atomic number 1
2. a unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second
   同义词：henry, H
3. the constant of proportionality relating the energy of a photon to its frequency; approximately 6.626 x 10^-34 joule-second
   同义词：Planck's constant, h
4. the 8th letter of the Roman alphabet
   同义词：H, letter h
5. (thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure
   同义词：heat content, total heat, enthalpy, H