如题所述
æ¨å¥½ï¼
å¯ä»¥ä½¿ç¨ç¦½çå »æ®ä¸ç¨äºæ°§åæ°¯æ¶æ¯åï¼ä½¿ç¨50-100ppmå²æ´å¯ä»¥æèæ¶æ¯ï¼é¤èãé¢é²ç¾ç ã