n.下向通風；下降氣流；倒風；下吸；回流；空氣陷坑
No watermark on a non-verbal-visual part of the silicone rubber layer easily scratched, Downdraft, expose their monlchamus photographicsensitive resin layer. 無水印版上否圖文局部的硅橡膠層便當被劃傷，而露不入其下吸不朱的感陡樹脂層。
