| 摘要 |
a frond line is formed by composing the parallel floating composite fronds; the frond line forms a array of fronds; the continuous folded sections of the fronds have aligned openings fixing in the screw type array by the soil bed; pitch or spacing control means is between the continuos folded sections of the frond line; a control means forms the spacing elements for being slided along the respective anchor line; is disclosed.
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