## 3 Experimental Process and Analysis
### Analysis of Variance  
The ANOVA table summarizes the results of the variance analysis, as shown in Table 8.  
As shown in Table 8, the \(p\)-value of the regression model was less than 0.0001, which means that the choice of the quadratic polynomial model is reasonable, and the relationship between the maximum electric field intensity value, \(y\), and the regression equation is extremely significant. Thus, the null hypothesis, \(H_{0}\), is not valid and can be rejected. The \(p\)-value of all linear terms were less than 0.0001, indicating that each variable in \(R_{1}\), \(h\), \(s\), and \(w\) is an extremely significant factor affecting the optimization objective. Except that the interaction between \(R_{1}\) and \(s\) was significant, the \(p\)-value of each of the other two was greater than 0.05, demonstrating the interaction between the two has little effect on the response. The \(p\)-values of the quadratic terms \({R_{1}}^{2}\) and \(s^{2}\)were less than 0.0001, and the significance was higher than the other two, which is an extremely significant factor. In addition, \(R_{adj}^{2}\) is 0.9841, which is very close to 1. The model can explain 98.41% of the test changes and better reflect the  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Run**} & \multicolumn{4}{c}{**Actual/mm**} & \multicolumn{4}{c}{**Coded**} & \multicolumn{2}{c}{\(E_{\text{max}}\)**Number of**} & \multirow{2}{*}{**DOFs**} \\ \cline{2-2} \cline{6-11}  & \(R_{1}\) & \(h\) & \(s\) & \(w\) & \(\overline{x}_{1}\) & \(\overline{x}_{2}\) & \(\overline{x}_{3}\) & \(\overline{x}_{4}\) & \(\text{/V/mm}\) & \\ \hline
19 & 20 & 20 & 2 & 50 & 1 & 1 & \(-\)1 & 1 & 10,083.12 & 2153 & 4073 \\
20 & 5 & 15 & 3.5 & 45 & \(-\)1.413 & 0 & 0 & 0 & 11,879.20 & 2102 & 4004 \\
21 & 13 & 15 & 3.5 & 45 & 0 & 0 & 0 & 0 & 9664.49 & 2090 & 3981 \\
22 & 20 & 10 & 2 & 40 & 1 & \(-\)1 & \(-\)1 & \(-\)1 & 9758.90 & 2137 & 4053 \\
23 & 13 & 15 & 3.5 & 45 & 0 & 0 & 0 & 0 & 9664.49 & 2090 & 3981 \\
24 & 20 & 10 & 2 & 50 & 1 & \(-\)1 & \(-\)1 & 1 & 10,391.28 & 2147 & 4006 \\
25 & 20 & 10 & 5 & 50 & 1 & \(-\)1 & 1 & 1 & 9179.16 & 2079 & 3961 \\
26 & 6 & 20 & 5 & 40 & \(-\)1 & 1 & 1 & \(-\)1 & 10,354.56 & 2082 & 3970 \\
27 & 13 & 15 & 3.5 & 45 & 0 & 0 & 0 & 0 & 9664.49 & 2090 & 3981 \\
28 & 20 & 20 & 2 & 40 & 1 & 1 & \(-\)1 & \(-\)1 & 9314.94 & 2145 & 4064 \\
29 & 13 & 15 & 3.5 & 35 & 0 & 0 & 0 & 0 & 9077.65 & 2086 & 3977 \\
30 & 6 & 20 & 2 & 40 & \(-\)1 & 1 & \(-\)1 & \(-\)1 & 11,046.17 & 2131 & 4047 \\ \hline \hline \end{tabular}
\end{table}
Table 6: _Cont._  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Factor** & **df** & **Standard Error** & **95\% CI Low** & **95\% CI High** & **Coefficient Estimate** \\ \hline Intercept & \(1\) & 54.99 & 9583.37 & 9817.79 & 12419.312 \\ \(R_{1}\) & \(1\) & 31.52 & \(-\)1120.49 & \(-\)986.12 & \(-\)371.458 \\ \(h\) & \(1\) & 28.29 & \(-\)290.01 & \(-\)169.40 & \(-\)55.687 \\ \(s\) & \(1\) & 28.29 & \(-\)588.97 & \(-\)468.36 & \(-\)783.092 \\ \(w\) & \(1\) & 28.29 & 275.97 & 396.58 & 84.888 \\ \(R_{1}h\) & \(1\) & 34.65 & \(-\)18.43 & 129.30 & 1.584 \\ \(R_{1}s\) & \(1\) & 34.65 & \(-\)175.73 & \(-\)28.00 & \(-\)9.701 \\ \(R_{1}w\) & \(1\) & 34.65 & \(-\)89.55 & 58.18 & \(-\)0.448 \\ \(hs\) & \(1\) & 34.65 & \(-\)57.65 & 90.08 & 2.162 \\ \(hw\) & \(1\) & 34.65 & \(-\)60.77 & 86.95 & 0.524 \\ \(sw\) & \(1\) & 34.65 & \(-\)95.39 & 52.33 & \(-\)2.870 \\ \({R_{1}}^{2}\) & \(1\) & 42.70 & 382.68 & 564.71 & 9.667 \\ \(h^{2}\) & \(1\) & 26.20 & \(-\)90.83 & 20.87 & \(-\)1.399 \\ \(s^{2}\) & \(1\) & 26.20 & 154.20 & 265.90 & 93.357 \\ \(w^{2}\) & \(1\) & 26.20 & \(-\)58.52 & 53.18 & \(-\)0.107 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Coefficients of ISM model.  
law of data changes with less experimental error and better fitting. Furthermore, from the confidence interval listed in Table 8, the significant items are also \(R_{1}\), \(h\), \(s\), \(w\), \(R_{1}\)s, \({R_{1}}^{2}\), and \(s^{2}\), for the upper and lower bounds of their confidence intervals do not contain zero.