Fig. 1. Calibration curves of carbon content in fly ash^[22]. (a) Na₂SiO₃ as binder; (b) KNO₃ as binder

Fig. 2. Comparison of breakdown of particle flow samples with different stream diameters^[28]

Fig. 3. Representative LIBS spectra of fly ash. (a) 190-300 nm band spectra; (b) 300-400 nm band spectra

Fig. 4. Structure schematic diagram and physical photographs of the LIBS automatic fly ash measuring device with melting furnace^[53]

Fig. 5. System schematic diagram of the online measurement device and field installation object^[55]

Fig. 6. Structure of LIBS detection device for carbon content of fly ash in flat stack type^[56]

1: Nd:YAG laser; 2: half-wave plate; 3: polarizing beam splitter; 4: bolt sleeve; 5: rear-silvered mirror; 6: spectrometer; 7: chiller; 8: energy meter; 9: focusing lens; 10: optical fiber; 11: conical funnel; 12: vibrator; 13: A-A section of the connection base; 14: smooth groove; 15: optical connector; 16: driving pulley; 17: guide pulley; 18: cleanout door; 19: conveying belt; 20: drive pulley; 21: shell

Fig. 7. Structural schematic diagram and photos of convenient fly ash carbon content online measurement device^[58]

1: measuring probe; 2: measuring and analyzing unit; 3: fly ash particles; 4: flue; 5: air curtain