This paper presents a study of the reflection of sound pulse from porous material in the ease that the impulse sound source and receiver are located on a line perpendicular to the surface of material.
本文提出当脉冲声源和接收点在同一条垂直于材料表面的直线上时，声脉冲从多孔材料反射的研究。
However, a vertical line sitting perpendicular to the top and bottom of the canvas has more of a tendency to convey a sense of height.
然而，与画布顶端和底端垂直的竖线往往更适于传递高度之感。
A pier does not necessarily need to run perpendicular to the shore line but may project under any Angle.
突堤式码头并不一定要和岸边垂直，可以以任何角度向外突出。
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