Fig. 1. Principle of direct absorption spectroscopy measurement

Fig. 2. Schematic diagram of experimental device

Fig. 3. Influence of temperature on ammonia absorbance simulated by HITEMP-TDLAS at different concentrations

Fig. 4. Mechanism of temperature effect on line strength

Fig. 5. Influence of temperature on ammonia absorbance simulated by HITEMP-TDLAS at different concentrations

Fig. 6. Influence of temperature on ammonia absorbance simulated by HITEMP-TDLAS at different concentrations

Fig. 7. Comparison of results before and after correction

Fig. 8. Ammonia spectral absorbance in the range of 25 ℃ to 1 005 ℃