短语词组短语torsional pendulum viscometer 扭摆粘度计worm spring torsional pendulum 蜗簧扭摆torsional pendulum analysis 扭摆分析torsional pendulum clock 扭摆钟trifilar torsional pendulum 三线扭摆系统modified torsional pendulum 扭摆法 返回 torsional pendulum