periodicit周期性, 周波periodicadj.周期的；定期的；间歇的；完句的periodic increment定期生长量periodic cusp wave周期尖波periodic inventory定期盘存periodic selection周期选择作用periodic operation周期性运转,定期运行periodic waveguide周期性波导管periodic statement定期报表periodic copolymer嵌段共聚物periodic scheduler周期进度表periodic structure周期性结构