• Journal of the Korean earth science society
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• v.26 no.6
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• pp.560-572
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• 2005

This study investigates the characteristics of atmospheric circulation and the heat source $(Q_1)$ related to the winter cold surge in Korea from 1979 to 1999. The occurrence frequency of cold surge is about one event per year and $60\%$ of the total events occurred during the former period, before 1989. During the cold surge, the pressure pattern shows more dominant east-west dipole circulation pattern in the lower troposphere and the effect of upper level trough is stronger than normal cases. Temperature falling pattern over Korea shows that the pattern opposite to the temperature structure over Lake Baikal and temperature change has opposite signs between the low-middle level and upper level, with the boundary at 400 hPa. The analysis of heat source shows that atmospheric cooling by cold advection during the cold surge is balanced by adiabatic warming due to downward motion, indicating that the movement path of cold core is associated with that of heat sink. Therefore, the movement mechanism of the heat source and sink should be well known for understanding the maintenance mechanism of cold surge and predicting cold surges.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.93-96
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• 2009

Advances in high speed flight technologies and engine efficiencies increase heat load on the aircraft. As the temperature of air flow is too high to cool the structure at hypersonic flight speeds, it is necessary to utilize the aircraft fuel as the primary coolant. By undergoing endothermic reaction, such as thermal decomposition or catalytic decomposition, aircraft fuels have heat sink potential. These fuels are called endothermic fuels. The endothermic reaction can be improved by catalysts, but limited by coke deposition. In this study the essential technologies of endothermic fuels are described, and intended to be used for basic research.