At the bottom of this plate, an aperture had been pierced exactly similar to the orifice of a letter box.
在那铁皮的下方，开了一个口，和信箱的口完全同一样。
2
The experimental results show that acoustic resistance of perforated plate is related to plate thickness, aperture diameter, numbers of aperture, acoustic frequency and airflow velocity.
研究表明：穿孔板的声阻与孔板厚度、孔径、穿孔数目、声波频率和气流速度等因素有关。
3
The stability and the precision of adjustment of large aperture servo reflector in laser system for nuclear fusion can be distinctively improved by using cross spring-plate shore.