RESUMO
Accurate prediction and control of the steel plate temperature in the laminar cooling process are very challenging. In this research, an experimental platform was built to measure the heat transfer characteristics of the steel plate in the process of matrix laminar spray cooling when the steel plate is one millimeter away from the upper surface. The "buried couple method" was used, including the cooling temperature and cooling rate. Then, the temperature and the integrated heat transfer coefficient at the steel plate surface were calculated by the time-sequential function method (TSFM). The obtained results show that the fast cooling stage under the water cooling condition occurred in the first 1.5 s, and the measuring point temperature decreased by 8%. The "re-reddening" phenomenon of the steel plate appeared with time, and the measuring point temperature increased by 37%. Second, the maximum calculated difference between the surface temperature and the measuring point temperature was 0.75 °C, and the integrated heat transfer coefficient conformed to the periodic boundary features. The comprehensive convective heat transfer coefficient on the surface was in agreement with the periodic boundary characteristics, and its value exhibited oscillatory attenuation with the cooling process, and the oscillatory peak period was about 6 seconds. Two methods, sequential function method (SFM) and finite difference method (FDM), were used to verify the correctness of TSFM.
RESUMO
Runx2 is a new transcription factor that takes part in odontoblast differentiation. This study is aimed at investigating the immunolocalization and expression of Runx2 in the process of dental pulp injury and repair using immunohistochemical technique. In normal dental pulp, positive staining can hardly be detected. In experimental groups, strong positive staining was detected at the site of the impaired pulp after 1 day, while only weak Runx2 staining was detected 3 days after operation. Five days later, a large number of stellate cells in the root apex expressed Runx2, and after 7 days, followed by the reparative dentinogenesis, Runx2 expression vanished slowly, then totally disappeared. Taken together, the expression of Runx2 has temporal and spatial specificity during different phases in rat tertiary dentinogenesis.
