periodicit周期性, 周波periodicadj.周期的；定期的；间歇的；完句的periodic detection定期检测periodic thickness调制波长periodic migration周期性洄游periodic weighting周期来压periodic potential周期势,周期电势periodic annealing周期退火periodic vibration周期振动periodic composite周期结构复合材料periodicity change周期变化periodic discharge周期性放电