For the effective seedling production of the hard shelled mussel, Mytilus coruscus, this study assessed the effects of the dietary value of live food, density, water temperature and salinity on growth and survival rate of the larvae. The optimal survival rate and growth rate were examined under differing conditions of water temperature, salinity, and rearing density for 30 days. The three groups were provided different feeding organisms, such as Isochrysis galbana and Teleaulax suecica. The mixtures were provided at a rate of 5×104 cell mL-1. The best growth was observed in the group with conditions 21℃ water temperature (16.2±9.1 μm), 33 psu of salinity (16.82±3.9 μm), 2500 individual m-2 (17.2±5.9 μm), and fed with 5×104 cell mL-1 of I. galbana and T. suecica mixture (16.0±7.3 μm). The highest survival rate was found in the group at conditions 18℃ water temperature (66.4%), 33 psu of salinity (24.4%), 2500 individual m-2 (65.8%), and fed with 5×104 cell mL-1 of I. galbana and T. suecica mixture (58.8%). We therefore conclude that the suitable culture conditions for the stable production of hard shelled mussel artificial seedlings was at 18 to 21℃ of temperature, 30 to 33 psu of salinity, 2500 to 5000 individual m-2 of rearing density, and feeding supplement of 5×104 cell mL-1 of I. galbana and T. suecica mixture under semi running water system.

해상 강교량은 특성상 혹독한 부식환경에 가설되어 있으며 장기간 공용중인 강구조물의 경우 염분에 의한 부식손상과 도막노화로 구조물의 정기적인 보수도장이 필요하다. 또한 부식손상과 도막노화, 온습도, 비래염분등의 다양한 원인에 의하여 발생된다. 하지만 도막표면에 부착되는 염분량은 비래염분량의 영향뿐만 아니라 구조형식 및 강우 유무에 따라 변화하게 되며, 해상강교량에서 12개월간 도막표면에 부착되는 염분량을 측정 하였다. 그리고 구조형식에 따라 누적 부착염분량의 차이로 도막노화 및 부식손상의 속도가 다르게 나타날 수 있으며, 보수도장을 위한 의사결정 과장에 기초자료로 활용할 수 있다.

The importance of maintenance in steel structures is to be emphasized according to increase of their service time. To protect the corrosion damages, the repainting on steel bridges are usually applied every 10 to 13 years by visual inspection. However, the coating durability was rapidly decreased by airborne salt under marine environment. In this study, the time-dependence deposited salts were measured at several types and locations of structural member in marine bridge.