1993년 1월부터 12월까지 한국 서해 군산시 오식도 조간대에서 채집한 대맛조개를 대상으로 정자형성과정 및 생식주기를 조직학적 및 투과형전자현미경으로 조사하엿다. 대맛조개(Solen grandis)는 자웅이체이다. 본 종의 완숙정자의 형태 구조는 다른 이매패의 정자들이 갖는 원시형(primitive type)으로 작은 두부와 한 개의 두모첨체를 가지며, 편모축사를 둘러싸고 있는 4개의 미토콘드리아로 이루어진 짧은 중편을 갖는 것이 관찰되었다. 완숙정자

Radiobeacons that carry corrections for global satellite navigation systems are currently being planned or installed in many countries. In early 1996, it was begun to send DGPS correction message from a marine radiobeacon station located in Changgi Got Lighthouse. It was the first test broadcast of DGPS correction data based on medium frequency of marine radiobeacon where transmission power and rate are 300W and 100bps respectively in Korea. However, there has not been any scientific study on the characteristic of the accuracy of a marine radiobeacon/DGPS. Accordingly, this paper investigates the accuracy of the system, which is currently operating in 310kHz. To do this , the real time differential correction in RTCM data was collected in an implemented system. And then the accuracy was analyzed related to the coverge of the radiobeacon/DGPS. As a result, it is verified that the differential positioning accuracy using the marine radiobeacon is sufficient to ensure the safety of marine activities around the coast of Korea.

A total of 24 surface sediment samples collected from coastal region and fronting of sea cliff on Cape Cod in southeastern Massachusetts, were analyzed to investigate the sediment transport mechanism. According to the result of grain-size analysis, the overall trend of grain size decreases from the north(Wood End Beach) to the south(Nauset Light Beach). The coarser materials tend to be deposited at the foreshore than at the backshore. Especially gravel content(%) is very high in northern beaches. The gravel fraction tended to concentrate at the toe of the beach. In addition to gravel, the beach and nearshore bar also tended to be deposite of very coarse sand and the finer fraction accumulate in the offshore bar. Grain-size analyses of sediment indicates that the coarsest sands including gravel accumulate in the beach and nearshore bar, the finer fraction winnowed out by wave action to be deposited in the offshore bar. The beach and nearshore bar sands and gravel are subsequently transported laterally by the wave-driven longshore drift, and finally they come to rest in the distal end of Provincetown Hook. The finer offshore sands are trnasported laterally to the south by net southward-directed longshore current.

1992년 1월부터 12월까지 1년간에 걸쳐 전북 군산, 선연리 조하애에서 채집된 개량조개, Mactra chinensis Philippi를 대상으로 생식세포 발달과 생식소 발달양상을 조사하기 위해 토과형 전자현미경으로 미세구조 변활르 관찰하였고, 정확한 산란기를 규명하기 위해 조직학적으로 생식주기를 조사하였다. 개량조개는 장웅이체이다. 난황형성과정은 난모세포의 발달정도에 따라 다르게 나타나고 있다. 전난황형성기 난모세포질 내에서는 핵주변 구여게 골지장

4개 주요 검조소의 기본수준점표 설정연혁을 개괄하였다. 이 검조소의 검조의 영점표고, 기본수준고, 그리고 주위기준점(Tidal Bench M막)의 자료를 수집검토하였다. 농어촌진흥공사, 수로국, 항만국 등이 조사한 지역평균 해면고(Local Mean Sea Level)를 비교하여 이들 4개 검조소지점(인천, 군산내.외항, 목포)의 평균해면고로 정의하였다. 기본수준면(DL), 평균해면(MSL), 대조평균만조면(HWOST) 등의 설계조위면을 추정하기 위하여

The accuracy for determining fishing ground and for setting fishing gear location, and the repeatability of ship position vary depending on fishing methods. Especially, Loran-C has been served to give fisherman highly accurate ship's position, and a number of fishing vessel are equipped with it's receivers. In this paper, in order to evaluate the accuracy of Loran-C fix of Korean chain in Korean southeast coast, the authors examined and analyzed the data of the receiver of Loran-C(LC 90, Furuno) and GPS(AccNav SportTM, Eagle) measured automatically and continuously for 2 seconds at interval of 5minutes during 2hours from 11th to 21st, July, 1996 at six observed points, that is, Pusan, Wolnae, Pangojin, Chongja, Kampo and Kuryongpo in Korean southeast coast. As the result obtained, Loran-C signals showed little fluctuation with good reprodutibility. Good stability of Loran-C signals was indicated by the small value of the standard deviation 0.064~0.094μ s. Although determination of the observed position could not be completely accurate, the extent of the error was estimated smaller than 0.35 nautical mile.