Figure 6

The combination of (SO2 + SO2F2)/(CF4 + CO2) and CF4/CO2 performs well because of the discrete characteristic except for the conflict between the pollution defect and gap defect.
The combination of (SO2 + SO2F2)/(CF4 + CO2) and CF4/CO2 performs well because of the discrete characteristic except for the conflict between the pollution defect and gap defect.