| 摘要 |
PROBLEM TO BE SOLVED: To provide a gravel mat which allows a gravel ball to be surely and firmly fixed to a base member. SOLUTION: This gravel mat is composed of the base member which is formed in a netty shape and the many gravel balls which are to be laid on a surface of the base member; the gravel ball is equipped with an approximately flat surface; an opening area of a mesh of the base member is equal to/smaller than half an area of the flat surface of the gravel ball; and the flat surface of the gravel ball is fixed to the base member. COPYRIGHT: (C)2004,JPO
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