## 3 Results
### Analysis and Impact of Interactions on the R. solani Cell Damage Rate
Response Surface Analysis of the Effect of PEF on the Absorbance Value at 510 nm of the R. solani Mycelium Suspension  
It can be seen from Table 1 that, after PEF treatment, most of the experimental samples of _R. solani_ have significant (\(p<0.05\)) or extremely significant (\(p<0.01\)) differences in their absorbance values at 510 nm. The quadratic multiple regression model that was established by response surface analysis is shown in formula (3). For formula (3), it can be known from Figure 2 that its independent variable, the primary term A and the secondary term A2 are significant (\(p<0.05\)), and the other terms are not significant. If the insignificant terms are eliminated, formula 3 can be simplified as follows:  
\[\mathrm{A_{510}}=4.518\times 10^{-3}-4.542\times 10^{-3}\mathrm{A}+7.523\times 1 0^{-3}\mathrm{*A^{2}} \tag{3}\]  
Among these, \(\mathrm{A_{510}}\) is the absorbance value at 510 nm after PEF treatment, measuring the amount of extracellular alkaline phosphatase that was selected under different treatment conditions to evaluate the degree of damage to the cell wall. It can be seen from Table 4 that the F value of the model describing the absorbance value at 510 nm is 4.05, and the \(p\) value is 0.0392, which indicates that the expression between the established absorbance value at 510 nm and the experimental control condition is significant (\(p<0.05\)) and the  
Figure 4: Response surface analysis of processing time and pulse duration. R value is 0.8391, indicating that the model has good fitting and high credibility. It can be seen from the data in Table 2 that the influence of the voltage and its quadratic term on the absorbance at 510 nm is extremely significant, while the influence of the quadratic term of time on the absorbance at 510 nm is not significant. 4.1 Analysis of the Interaction between Voltage Amplitude and Processing Time, and Its Effect on the Absorbance Value at 510 nm  
Figure 5 shows the response surface of the voltage amplitude and processing time vs. the absorbance value at 510 nm of the _R. solani_ mycelium suspension at a pulse duration of 45 \(\upmu\)s. When the pulse duration is at an intermediate level, the effect of increasing the voltage amplitude on the suspension absorbance at 510 nm is similar for different processing times; the absorbance first decreases from 1.43% to 0.37%, and then slightly increases with the voltage amplitude. At different voltage amplitudes, the effect of increasing processing time on the suspension absorbance value at 510 nm is similar, with the processing time increasing slowly. It can be seen from Table 4 that the change in the quadratic term of the voltage amplitude has a significant effect on the absorbance value at 510 nm of _R. solani_ (\(p<0.01\)). The interaction between the voltage amplitude and processing time is the most obvious when the voltage amplitude is 15 kV and the processing time is 5 min. At this point, the absorbance value reaches 0.0199. 4.2 Analysis of the Interaction between Voltage Amplitude and Pulse Duration, and Its Effect on the Absorbance Value at 510 nm of _R. solani_ mycelium suspension  
Figure 6 shows the response of the voltage amplitude and pulse duration vs. the absorbance value at 510 nm of _R. solani_ mycelium suspension at a processing time of 3 min. The effect of increasing voltage amplitude on the suspension absorbance value at 510 nm is similar under different pulse durations when the processing time is at an intermediate level. The absorbance first decreases from 1.34% to 0.45%, and then increases with the voltage amplitude; under different voltage amplitudes, the effect of increasing the pulse duration on the suspension absorbance value at 510 nm is similar. As the pulse duration slightly increases, it decreases slowly, and the overall effect is not obvious. Additionally, it can be seen from Table 4 that the change in the quadratic term of the voltage amplitude has a significant effect on the suspension absorbance value at 510 nm (\(p<0.05\)).