## 5 Results and Discussion
### Results of Preliminary Experiment
However, as can be seen from Figure 8b, when comparing the temperature results measured by the methods of Figure 7, the temperature measured by the reconstruction method using half absorbance was considerably higher than the temperature measured by the multi-peak Voigt fitting method at the center temperature of the electric furnace at 1073.15 and 1173.15 K. Thus, it was derived that the temperature measured from the reconstruction method using half absorbance tended to be lower than the temperature measured by the multi-peak Voigt fitting method as the temperature increased to 1573.15 K. As shown in Figure 2b, it was confirmed that the ratio of the two partially overlapped H\({}_{2}\)O linestrengths was significantly different when the temperature decreased and increased at 1267.66 K. The reconstruction method using half absorbance did not sensitively consider the increased area due to the overlapped center area of the two partially overlapped H\({}_{2}\)O absorption signals when the absorbance area A1 was considerably larger than A2 (Figure 8a), such as the absorption signals measured at 1073.15 K. The absorbance area A2 increased excessively with the amount of absorbance area A1 overlapped with the original absorbance area A2. It was expected an error in temperature measurement caused by the reconstruction method using half absorbance, as a result of analyzing the increased absorbance area A2 due to the absorbance area A1 instead of the original A2 absorbance area. As shown in Figure 8a, the multi-peak Voigt fitting method showed a large difference, unlike the reconstruction method using half absorbance, because it considered the increased area at the center of the two partially overlapped H\({}_{2}\)O absorption signals. However, as can be seen from the analysis results of Figure 8b, it was considered that the center area of the two partially overlapped H\({}_{2}\)O absorption was not significantly affected because the two H\({}_{2}\)O absorption signals analyzed by the reconstruction method using half absorbance had similar linewidth in the temperature range of 1250-1350 K.  
Figure 9 is a graph of the absorption signals at 1073.15 and 1473.15 K analyzed by the reconstruction method using half absorbance. As can be seen from Figure 9a, when A1 was larger than A2, the large absorption area A1 affected the increase of the absorption area A2, which caused an error. However, as shown in Figure 9b, when the absorbance areas A1 and A2 were similar, they increased in the same proportion. Therefore, the difference between the temperature measured by the two methods analyzed within 1250-1350 K showed a similar tendency. As a result, the two partially overlapped H\({}_{2}\)O absorption signals throughout the preliminary experiment were more accurately analyzed for areas A1 and A2 derived from the multi-peak Voigt fitting method. It was confirmed that the temperature measured by multi-peak Voigt fitting showed a linear tendency similar to the center temperature of the electric furnace and had higher temperature measurement sensitivity. Figure 8: (**a**) Multi-peak Voigt fitting for measured data at 1073.15 K, and (**b**) comparison of the experimentally obtained temperature using TDLAS with measured temperature using T/C in the electric furnace.