| 摘要 |
The panel (1), used for making an anti-noise screen, is made from moulded or pressed concrete containing treated wood particles, and it has a series of cavities (4) in the side (3) facing away from the source of noise that act as Helmholtz resonators. Each cavity has a narrow, slightly diverging well in its base, and their open ends, making up at least 25 per cent of the panel's surface, are covered by a layer of an absorbent fibre or foam material, such as rock wool, glass wool or wood fibres in cement. The panel can also be made from natural porous materials such as pozzolana, pelletised slag, clay, expanded lava or clinker. |
