| |||
vibration frequency | |||
wave frequency | |||
fluctuating frequency |
波动频率 : 14 phrases in 9 subjects |
Air defense | 2 |
Aviation | 3 |
Electric machinery | 1 |
Electronics | 3 |
Information technology | 1 |
Metallurgy | 1 |
Oil / petroleum | 1 |
Space | 1 |
Steel production | 1 |