8 19~21 ʶǾƿ ֵǴ ACS(American Chemical Society) мȸ ȸ Ƽ մϴ. ACS 164,000 ȸ ϰ ִ ко߿ Ը ū ȸԴϴ. ̹ мȸǿ 뷫 14,000 Դϴ.