Figure 4b. Temperature response surface for NaCl pretreatment. (a, b) Two drawings graphically represent the three-dimensional relationship of temperature at 2 cm from the RF electrode with NaCl concentration and NaCl volume in two different projections. Note the steep upslope to the temperature maximum, which is the region that fits a modified gamma-variate function that corresponds to the generator energy-dependent region. Beyond the maximum temperature, in the generator current-limited region, temperature decreases exponentially.