Fig. 1. Overall assembly structure of gallium fixed-point blackbody radiation source used for sea surface temperature radiometer

Fig. 2. System block diagram of gallium fixed-point blackbody's phase transition recurrence experiment

Fig. 3. Emissivity of gallium fixed-point blackbody

Fig. 4. Results of phase transformation recurrence of gallium under electric heating

Fig. 5. Deviation between the phase transition results and the melting point of gallium under electric heating

Fig. 6. Gallium melting curves at different electric heating powers

Fig. 7. Deviation between the measured results and the melting point of gallium at different electric heating powers

Fig. 8. Results of phase transformation recurrence of gallium under water-bath heating

Fig. 9. Measurement results of the blackbody combined ISAR under electric heating

Fig. 10. Measurement results of the blackbody combined ISAR under water-bath heating

Fig. 11. The synchronized measurement results collected by ISAR and FLUKE 1524 thermometer and the difference between ISAR's data and FLUKE 1524 thermometer's data under electric heating and water-bath heating conditions when the blackbody is heated by electricity near the gallium phase transition plateau