## 3 Results
### Electrical Signal Analysis
Electrical conductivity measurements were performed for various dielectric media during the experimental process, and equivalent resistance values for the dielectric media within the drill hole were calculated. The deposited energy and electrical energy deposition efficiency during the electrical explosion process for each dielectric medium were computed using Equations (4) and (5), with the relevant data summarized in Table 4. Analysis of the data in Table 4 reveals a positive correlation between the electrical conductivity of the dielectric media and the electrical energy deposition efficiency, with the exception of the CO\({}_{2}\)-dissolved liquid. Notably, potassium chloride and sodium chloride solutions exhibit the highest electrical conductivities at 61.8 \(\times\) 10\({}^{3}\) uS/cm and 59.9 \(\times\) 10\({}^{3}\) uS/cm, respectively. These values are 68 and 66 times higher than the electrical conductivity of tap water (908 uS/cm). Correspondingly, these two dielectric media demonstrate significantly enhanced electrical energy deposition efficiencies, with increases of 12% and 8.4%, respectively, compared to the tap water control group. These improvements are markedly higher than those observed for other dielectric media tested. Despite the similar electrical conductivity of the CO\({}_{2}\)-dissolved liquid to tap water, the former exhibited the highest electrical energy conversion efficiency of 60% during the electrical explosion process of all the media tested in this experimental series. This observation suggests that the increased pressure within the drill hole, resulting from gas bubble dissipation, delays the discharge breakdown moment and prolongs the discharge duration, thereby increasing the stored energy. Analysis of Figure 7c reveals that the CO\({}_{2}\)-dissolved liquid dielectric medium requires a longer time to reach peak deposited power. A comprehensive evaluation of rock-breaking effects indicates that the combined action of hydrostatic pressure and bubble pulsation significantly enhances the electrical energy deposition efficiency during the explosion process. However, this enhancement is accompanied by a reduction in the intensity of the electrohydraulic shock wave, consequently decreasing rock breaking efficiency. Further analysis of two experimental data pairs--copper (II) oxide powder suspension versus tap water and iron (III) oxide powder suspension versus sodium chloride solution--reveals an intriguing phenomenon. Despite having relatively low electrical conductivities in the same order of magnitude, both copper (II) oxide and iron (III) oxide powder suspensions demonstrate notably higher electrical energy deposition efficiencies, exceeding their counterparts by 2.5% and 0.8%, respectively. Integrating this observation with the \begin{table}
\begin{tabular}{c c c c c} \hline  & **Electrical** & **Equivalent** & **Deposited Energy** & **Energy Deposition** \\  & **Conductivity** & **Resistance** & **(\(\mu\)S/cm)** & **Efficiency** \\  & **(\(\mu\)S/cm)** & **(\(\Omega\))** & **(\(\mu\)S/cm)** & **Energy Deposition** \\ \hline Aluminum powder & & & & \\ suspension & 790 & 377 & 2.42 & 38.7\% \\ \hline Iron powder suspension & 802 & 371 & 2.57 & 41.1\% \\ \hline Copper (II) oxide powder & & & & \\ suspension & 873 & 341 & 2.97 & 47.5\% \\ \hline Iron (III) oxide powder & & & & \\ suspension & 4.91 \(\times\) 10\({}^{3}\) & 60.6 & 3.39 & 54.2\% \\ \hline Potassium chloride solution & 61.8 \(\times\) 10\({}^{3}\) & 4.8 & 3.56 & 57\% \\ \hline Sodium chloride solution & 59.9 \(\times\) 10\({}^{3}\) & 4.9 & 3.34 & 53.4\% \\ \hline CO\({}_{2}\)-dissolved liquid & 711 & 419 & 3.72 & 60\% \\ \hline Water & 908 & 328 & 2.81 & 45\% \\ \hline \end{tabular}
\end{table} 
Table 4: Electrical signal data of electrically exploding wires in different dielectric media. deposited power waveforms shown in Figure 7c, it is hypothesized that the micrometer-sized metal oxide powder particles absorb a portion of the electrical energy during the explosion process, resulting in a delayed discharge breakdown.