NUCLEATION AND CHARACTERISTICS OF LIQUID-NITROGEN

This paper describes experiments on a refrigerating catalyst-liquid ni trogen (LN)-in different cloud chambers and their results. The nucleat ion threshold temperature of liquid nitrogen is 0 degrees C, and when the temperature less than -2 degrees C, the ice nucleation rate is abo ut 10(12) g(-1). This indicates that LN can be employed in artificial precipitation enhancement and artificial supercooled fog dispersal act ivities. It is found in the experiments that in fogs with a temperatur e slightly above 0 degrees C, liquid nitrogen can play a role of broad ening the fog drop spectrum, increasing the number of big droplets and decreasing the number of small ones. In addition, the application of microvideo and IR technology in cloud chamber experiments is also desc ribed.