## 3 Results
### Analysis of Nanopore Structural Parameters  
The nanopore structural parameters of the samples were analyzed using a combination of Nanoscope Analysis software and the open-source Gwyddion software [36]. Roughness parameters were initially obtained through the roughness analysis feature in Nanoscope Analysis software and were subsequently used to derive pore parameters. However, for other nanopore structural parameters, the watershed method within the grain analysis tool of Gwyddion software was employed. The watershed method treats images as geographical  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample Number**} & \multirow{2}{*}{
\begin{tabular}{c} **V\({}_{\rm{at}}\)** \\ **(wt\%)** \\ \end{tabular} } & \multicolumn{4}{c}{**Nanopore Parameters**} & \multicolumn{4}{c}{**Surface Roughness**} \\ \cline{3-10}  & & & & & & & & \\ \hline AH-1 & 33.17 & \(2249\pm 45\) & 16.75 \(\pm\) 0.34 & 3.79 \(\pm\) 0.08 & 0.63 \(\pm\) 0.013 & 4.55 \(\pm\) 1.24 & 5.83 \(\pm\) 1.67 & \(-0.279\pm 0.027\) & 3.23 \(\pm\) 0.359 \\ \hline HB-1 & 27.96 & \(3682\pm 74\) & 18.65 \(\pm\) 0.37 & 6.84 \(\pm\) 0.14 & 0.76 \(\pm\) 0.015 & 4.39 \(\pm\) 1.16 & 5.66 \(\pm\) 1.58 & \(-0.219\pm 0.003\) & 3.74 \(\pm\) 0.314 \\ \hline SX-1 & 14.51 & \(4361\pm 87\) & 9.72 \(\pm\) 0.20 & 5.44 \(\pm\) 0.11 & 0.82 \(\pm\) 0.016 & 3.99 \(\pm\) 0.95 & 5.43 \(\pm\) 1.62 & \(-0.508\pm 0.121\) & 3.93 \(\pm\) 0.989 \\ \hline SX-2 & 13.53 & \(4846\pm 97\) & 10.36 \(\pm\) 0.21 & 7.37 \(\pm\) 0.15 & 0.86 \(\pm\) 0.017 & 2.54 \(\pm\) 1.13 & 3.29 \(\pm\) 0.84 & \(-0.243\pm 0.013\) & 3.96 \(\pm\) 0.224 \\ \hline SX-3 & 12.67 & \(4564\pm 91\) & 9.37 \(\pm\) 0.19 & 8.57 \(\pm\) 0.17 & 0.84 \(\pm\) 0.017 & 2.27 \(\pm\) 0.58 & 2.95 \(\pm\) 0.68 & \(-0.315\pm 0.042\) & 4.15 \(\pm\) 0.146 \\ \hline SX-4 & 9.61 & \(5248\pm 105\) & 8.34 \(\pm\) 0.17 & 11.36 \(\pm\) 0.23 & 0.92 \(\pm\) 0.018 & 1.54 \(\pm\) 0.34 & 1.98 \(\pm\) 0.53 & 0.293 \(\pm\) 0.027 & 4.64 \(\pm\) 0.359 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Nanopore Structure Parameters and Surface Roughness of Coal Samples.  
landscapes and simulates a flooding process for image segmentation, enabling automatic identification of physical boundaries in complex images, making it particularly suitable for complex scenarios. By controlling the number of steps in grain positioning, the drop size, and the threshold value, followed by an inversion of height operations, the pore characteristics of each sample were efficiently and quantitatively analyzed.  
Analysis of coal samples using the watershed method in Gwyddion software yielded the number of pores, average pore diameter, areal porosity, projected area of total pores, and boundary length of total projection. These values were further processed to obtain the required pore structural parameters, with specific numerical values presented in Table 2. The number of pores in the samples ranged from 2249 to 5248, and the average pore diameter ranged from 8.34 nm to 18.65 nm. The areal porosity ranged from 3.79% to 11.36%, indicating variations due to changes in volatility. The shape factor ranged from 0.63 to 0.92, suggesting significant differences in the shapes of nanopores within the coal.