• The Korean Journal of Zoology
• /
• v.26 no.3
• /
• pp.193-202
• /
• 1983

Inversion at variable time of the uncleaved eggs of Rana nigromaculata and Rana dybowskii was emplyed to study the mechanisms of early embryogenesis. The response to inversion varied between those two spcies. If the eggs were inverted at early time it was possible to change the site of the first cleavage furrow of Rana nigromaculata-it appeared on the original vegetal hemisphere (OpG side). However, the first cleavage furrow of Rana dybowskii was not changed at all no matter what its inversin time was-it always appeared on the original animal hemisphere (G. side). In the inverted Rana nigromaculata embryos the size of the blastomeres on the vegetal hemisphere was always smaller than those of animal hemisphere. On the ocntrary, the cleavage pattern of Rana dybowskii was not altered. Results of the histological works for the inverted eggs suggest that the different responses to inversion might be caused by the fact that the extent to which the redistribution of the egg components such as cleavage nuclei and yolk platelets are different.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
• /
• v.23 no.1
• /
• pp.18-33
• /
• 1995

Under the synoptic scale strong westerly winds flowing over the large steep mountains in the eastern coastal region, the strong downslope wind storms such as internal gravity waves should be generated in the lee-side of mountain. Int he daytime as sea breeze circulation induced by meso-scale thermal forcing from sea toward inland confines to the offshore side of coastal sites due to the eastward internal gravity waves. Thus, surface winds near the coastal seas were relatively weaker than those in the open sea or the inland sites. Evidently, two different kinds of atmospheric circulations such as an internal gravity wave circulation with westerly wind and a sea breeze circulation with both easterly wind near the sea surface and westerly in the upper level were apparently produced. Under this situation the atmospheric pollutants at Kangnung city should be trapped by two different circulations in the opposite directions and resulted in the high concentrations of Total Suspended Particles (TSP) and ozone (O3). At night a meso-scale land breeze from land toward the more intensification of westerly winds in the coastal regions. The concentrations of TSP controled by the strong surface winds blowing from the mountain side toward the coastal sea were relatively higher at night than those in the daytime case and the concentrations of O3 due to the downward transport of ozone from the upper atmosphere toward the surface were also much higher at night than during the day. Consequently, the atmospheric pollutant concentrations in the mountainous coastal region under the downslope wind storms were higher than those after and before the occurrences of wind storms.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.8
• /
• pp.611-620
• /
• 2018

For the past decades, the analytic model for distributed surface roughness has been developed to improve the accuracy of the icing simulation code. However, it remains limitations to validate the developed model and determine the empirical parameters due to the absence of the quantitative experimental data which were focused on the surface state. To this end, the experimental study conducted to analyze the ice covered surface state from a micro-perspective. Above all, the tendency of the smooth zone width which occurs near the stagnation point has been quantitatively analyzed. It is observed that the smooth zone width is increased as growing the ambient temperature and freestream velocity. Next, the characteristics of the ice covered surface under rime and glaze ice have been analyzed. For rime ice conditions, ice elements are developed as the opaque circular corn in the opposite direction of freestream. The height and interval of each circular corn are increased as rising the ambient temperature. For glaze ice conditions, numerous lumps of translucent ice can be observed. This is because the beads formed by gravity concentrate and froze on the lower surface.