| | | | | | 25 25 | | | | | | | | | 1. | | | | | | | | 2. | 0.005%~ 0.01% | | | | | 3. | | | 4. | | | 5. | | | | | | 30~50 | | | | | | | | | | | | | | | | | | | | | |