当否 meaning in Chinese

justice

The reason that the noise is lower with inclining tongue is : 1 ) both the radius of the tongue and the gap between the tongue and the blade are changed across the wideth ; 2 ) the phase angle between blade and the tongue is changed across the wideth , therefore the peak value of the noise do not appear at the same time , so the peak value of the noise with inclining tongue is much lower than the straight one . the influence of the expanded angle of the shell of the fan on the noise was invested experimentally , and the optimal angle was got
倾斜蜗舌降噪的主要原因是：一是改变了从气流入口侧到风机轮盘的蜗舌间隙和蜗舌半径；二是改变了叶轮与蜗舌非定常相互作用的相位差，使其产生噪声也有相位差，迭加的结果进一步降低了噪声。另外，试验研究了不同蜗壳扩张角对风机噪声及效率的影响规律，蜗壳扩张角选择当否，对效率和噪声影响较大。