firs[计] 先前的firn.枞树；冷杉；枞木firing transformer爆破变压器firing time period燃烧速度firing cyclic time射击循环时间FIR differentiator有限响应微分器firing probability射击概率firing-pin group击发装置fir control system[计] 射击指挥系统FIR interferometer远红外干涉仪firing association射总Fir or pine wood.冷杉木材或松木木材