地磁水平分量（the horizontal component of terrestrial magnetism）的符号
海洛因（heroin）
abbr.(缩略词)
（铅笔心）硬的（=hard）
Noun:
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
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
the constant of proportionality relating the energy of a photon to its frequency; approximately 6.626 x 10^-34 joule-second
the 8th letter of the Roman alphabet
(thermodynamics) a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure;
"enthalpy is the amount of energy in a system capable of doing mechanical work"
