Research on one-dimensional phase change heat transfer characteristics based on instrument compartment structure.

To address the issue of electronic equipment failure inside the instrument compartment due to aerodynamic heating during high-speed flight. Combining the heat transfer characteristics of phase change materials, a new instrument compartment structure was proposed as the research subject based on phase change materials. While studying the heat transfer characteristics of this structure, one-dimensional phase change heat transfer theoretical model was constructed based on the Lightfoot integral equation method, and the corresponding analytical solution was obtained. To explore the temperature change law of the instrument compartment structure and verify the rationality of the theoretical model, the new thermal experiment was carried out for the instrument compartment structure. Compared with the aluminum alloy instrument compartment structure, the experimental results show that the instrument compartment structure design based on phase change materials could effectively reduce the temperature of the structure itself, and the experimental data are in good agreement with the theoretical calculation results, which verified the rationality of the theoretical model and provided a scientific basis for the practical application of phase change materials in instrument compartment structures.

Effects of Pulmonary Surfactant Combined with Noninvasive Positive Pressure Ventilation on KRT-14 and ET-1 Levels in Peripheral Blood and Therapeutic Effects in Neonates with Respiratory Distress Syndrome.

This study is aimed at exploring the effect of pulmonary surfactant (PS) combined with noninvasive positive pressure ventilation on the levels of Keratin-14 (KRT-14) and Endothelin-1 (ET-1) in peripheral blood and the therapeutic effect of neonatal respiratory distress syndrome (NRDS). Altogether 137 cases of neonates with respiratory distress syndrome treated in our hospital from April 2016 to July 2018 were collected. Among them, 64 cases treated with noninvasive positive pressure ventilation were considered as the control group, and 73 cases treated with PS combined with noninvasive positive pressure ventilation were considered as the observation group. The expression of KRT-14 and ET-1 in the two groups was compared. The therapeutic effect, death, complications, and blood gas indexes PaO2, PaCO2, and PaO2/FiO2 in the two groups were compared. Receiver operating characteristic curve (ROC) was applied to analyze the diagnostic value of KRT-14 and ET-1 in the therapeutic effect of NRDS. The effective rate of the observation group was higher than that of the control group. After treatment, PaO2 and PaO2/FiO2 in both groups were notably higher than that before treatment, while PaCO2 was notably lower than that before treatment. And after treatment, the levels of PaO2 and PaO2/FiO2 in the observation group were remarkably higher than that in the control group; PaCO2 was notably lower than that in the control group. After treatment, the levels of KRT-14 and ET-1 in the two groups were remarkably lower than those before treatment, and the levels of KRT-14 and ET-1 in the observation group were considerably lower than those in the control group after treatment. ROC curve showed that the area under the curve (AUC) of KRT-14 was 0.791, and the AUC of ET-1 was 0.816. PS combined with noninvasive positive pressure ventilation can notably improve the therapeutic effect of NRDS. KRT-14 and ET-1 levels may be potential therapeutic diagnostic indicators.