decayv.(使)衰退；(使)腐败；(使)腐烂n.衰退；腐烂；腐败decaying pulse衰变脉冲decay kinetics衰减动力学decaying speed衰减速率decay function时间衰退函数decayed timber腐朽木decay of power功率降低decay estimate衰减估计decay constant裂变常数decay electron衰变电子decayed source衰变源