## 3 Results
### Analysis and Impact of Interactions on the R. solani Cell Damage Rate  
During the data treatment process, the regression equation of the experimental results was established using Design Expert software, and the quadratic multivariate regression models were established between the _R. solani_ cell membrane damage rate, the absorbance value at 510 nm, and the voltage, pulse duration and processing time of PEF processing. Table 4 shows the results of the variance analysis. In Table 3, the cell damage rate of PEF-treated _R. solani_ is significantly higher than that of CK, and there are significant differences in each experimental group (\(p<0.05\)), most of which have extremely significant differences (\(p<0.01\)). Analysis of Variance (ANOVA) of Design-Expert was performed to obtain the coefficients of the final equation for better accuracy and carry out variance analysis of various models, and it concluded quadratic model as the best model. The quadratic multiple regression model between the cell damage rate and the _R. solani_ influencing factors was established, as shown in formula (2). Based on Table 4, it can be seen that in this case, the significance test \(p<0.05\) indicates that the model is statistically significant. For formula (2), it can be known from Table 4 that its independent variables the once term A and B and the quadratic term A\({}^{2}\) and B\({}^{2}\) are significant (\(p<0.05\)), and the other terms are not significant. If the insignificant terms are eliminated, formula 2 can be simplified as follows:  
\[\text{PR}=0.22+0.064\text{+A}+0.080\text{+B}+0.10\text{*A}^{2}-0.083\text{+B}^ {2} \tag{2}\]  
PR is the cell damage rate of PEF-treated _R. solani_ used to detect the degree of cell membrane damage; A is the pulse voltage amplitude, in kV; B is the processing time, in min. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Experiment** & **Voltage** & **Time/min.** & **Pulse** & **Cell Membrane** & **510 nm** \\
**Number** & **Amplitude/kV** & **Duration/μs** & **Damage Rate** & **Absorbance** \\ \hline CK & 0 & 0 & 0 & 0 & 0 \\  
& 0.00467 \\ \hline \hline \end{tabular} Note: ** in the table represents significance as \(p<0.05\); *** in the table represents extremely significance as \(p<0.01\).  
\end{table} 
Table 3: PEF treatment orthogonal experiment results. From Table 4, it can be concluded that the F value of the cell damage rate is 5.39 and the \(p\) value is 0.0186. Therefore, the relationship between the established cell damage rate and experimental factors is significant (\(p<0.05\)), and the R\({}^{2}\) is 0.8739, which shows that the model fitting is good and the reliability of the experimental model is high. From the data in Table 3, we can see that the influence of the quadratic term of the voltage on the cell damage rate is extremely significant, and the influence of the quadratic term of the pulse duration on the cell damage rate is not obvious. 3.1 Analysis of the Interaction between Voltage Amplitude and Processing Time, and Its Effect on the _R. solani_ Cell Membrane Damage Rate  
Figure 2 shows the response surface of the voltage amplitude and processing time vs. the _R. solani_ cell membrane damage rate 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 _R. solani_ cell membrane damage rate is similar for different processing times, and the cell membrane damage rate first decreased slightly from 12.7% to 5.8%, and then increased continuously with the voltage amplitude. Under different voltage amplitudes, the effect of cell membrane damage that is caused by increasing the processing time is similar, and the rate of cell injury first increased from 22.84% to 26.53% and then decreased slightly with the processing time. It can be seen from Table 4 that the change in the quadratic term of the voltage amplitude has a significant effect on the _R. solani_ cell membrane damage rate (\(p<0.01\)).