X, Y정자를 분리하여(sexing techlology)필요한 성을 조절한 배아의 연구가 아직 실용화되지 않고 있다 본 연구는 이에 대한 기초연구로서 돼지의 X 정자와 Y정자를 분리하기 위하여 불연속 percoll농도구배를 제조한 후 상층에 정액을 분주하여 120g에서 20분간 원심분리 하였다. 분리된 각 층의 정자를 회수(710 sperms/ml)하여 genomic DNA를 추출한후, PCR 방법을 이용하여 Y 염색체의 성 결정 유전자(TDF)인 SR

The technology of navigational instruments and the profession of going to sea have entered a time of dramatic change. A paradigm shift is taking place which will eventually make the industry unrecognizable to those who first went to sea only twenty years ago. This change is most emphatically seen in three areas: Automatic Identification System(AIS), Electronic Chart Display and Information System(ECDIS), and Voyage Data Recoreder(VDR). In order to make these new instruments to be fitted on board commerical ships, international requirements for enhacing the safety of navigation on the world's waterways, the Chapter V of International Convention for the Safety of Life at sea, 1974 as ameded(hereinafter referred to as "SOLAS"), are being also changed.o changed.