For a conventional helicopter , the tail rotor is one of primary sources for helicopter noise 尾桨是直升机的主要噪声源,降低尾桨噪声对控制直升机的噪声水平具有重要意义。
The machine has to be operated in an environment that is free from strong noise sources such as high - frequency welder 同时应在不受高频焊接机等强噪声源影响的环境下使用。
Acoustics - determination of sound power levels of noise sources using sound intensity - part 2 : measurement by scanning 声学.用声密度测定噪声源的声能级.第2部分:扫描法测定
Acoustics - determination of sound power levels of noise sources using sound pressure - precision methods for reverberation rooms 声学.利用声压测定噪声源的声级.混响室精确法
Acoustics - determination of sound power levels of noise sources using sound intensity - measurement at discrete points 声学.利用声音强度测定噪声源功率级.第1部分:离散点测量
To reduce interior noise of a passenger compartment measures are taken in the propagation route and the accepter 对于铁路客车车内降噪,主要从噪声源和传声途径两个方面采取措施。
Acoustics - determination of sound power levels of noise sources using sound pressure - precision methods for reverberation rooms 声学.用声压法测定噪声源的声强级.混响室的精确法
Acoustics - determination of sound power levels of noise sources using sound pressure - survey method using a reference sound source 声学声压法测定噪声源声功率级使用标准声源简易法
According to the distribution of noise source and characteristics , the enclosure is divided into four control regions 根据噪声源的分布及控制特点,把箱体内噪声控制分为四个控制区。
Acoustics - determination of sound power levels of noise sources using sound intensity - part 1 : measurement at discrete points 声学声强法测定噪声源的声功率级第1部分:离散点上的测量