• 한국해양공학회지
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• 제28권6호
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• pp.527-532
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• 2014

The thickness of Arctic sea ice is a particularly significant factor in Arctic shipping and other ice-related research areas such as scientific sea ice investigations and Arctic engineering. In this study, the relation between the measured sea ice thickness and freeboard on the Chukchi and Beaufort Seas during the 2010 and 2011 Arctic cruise of the icebreaking research vessel "Araon" were considered. An assumption of hydrostatic equilibrium was used to estimate the ice thickness as a function of the freeboard. Then, to examine the degree of error, a sensitivity analysis of the thickness estimation of the sea ice was conducted. The error in the density and depth of the snow and the error in the density of the seawater were subordinate parameters, but the density of the ice and the freeboard were the primary parameters in the error calculation. The presented relation formula showed fairly close agreement between the calculated and measured results at a freeboard of >0.24 m.

• ALGAE
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• 제18권4호
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• pp.321-331
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• 2003

Cryopreservation of sporothalli of the red alga Porphyra (P. seriata, P. yezoensis, P. tenera, P. pseudolinearis and P. dentata) was performed by the two-step cooling method in liquid nitrogen. The algal samples were suspended in various cryoprotective solutions, and slowly cooled to -40$^{\circ}C$ in 4 hours using a programmed freezer. After the first slow cooling the suspensions with cryoprotectants were immediately immersed in liquid nitrogen. The suspension from the programmed freezer was thawed quickly by agitation of the vial in a water bath at 40°C. When ice in the suspension of cryogenic vial was mostly melted, the vial was transferred to an ice bath for complete melting of the residual ice. The cryoprotectants in the vial were washed off by gradual dilution with seawater. The viability of the cell was assessed with neutral red staining. The viability of Porphyra samples ranged 54.6-70.9% when the mixed suspension of 10% dimethylsulfoxide and 0.5 M sorbitol in 50% seawater used as a cryoprotectant.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.329-332
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• 2003

Aquaculture have been important role to supply food resources for mankind. However, competitive power of domestic mariculture industry was declined due to increase of labor and feed expenditures, and quantity import of low-priced livefishes from the developing underdeveloped nations in North and South East Asia. Mass production and quality enhancement can be pointed out to overcome such an industrial environment in this decade. To meet these requirement, movable mariculture base remodeling feasible vessel of chemical tanker or crude oil carrier has been proposed for more advanced mariculture management system by using deep seawater from about 200m which is sustainablely clean, nutrient-rich and cold seawater. Deep seawater can be applied for control of seawater temperature for mariculture base and cultivation phytoplankton and seaweed as feed. Besides mariculture, strategic marketing can be implemented by raw water and ice of deep seawater. Feasibility of applying deep seawater was considered after evaluating general movable mariculture base and management system.

• Journal of Advanced Marine Engineering and Technology
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• 제35권4호
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• pp.373-378
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• 2011

해수 히트펌프를 이용한 냉동법 담수화시스템의 개발을 위한 시스템 설계 및 성능 해석을 수행하였다. 해수 히트펌프시스템의 열역학적 모델은 냉동사이클을 이용하였고, 이를 해수 담수화시스템에 적용하였다. 응축기의 유입 해수온도 및 증발기의 얼음 생성 비율에 따른 해수 히트펌프 시스템의 성능을 분석하고, 이에 따른 담수 생산량 및 담수 1kg 생산에 대한 소요 에너지 등 냉동법 담수화 시스템의 성능을 비교 분석하였다. 압축기 소요동력 및 응축기 용량은 응축기로 유입되는 해수온도가 감소함에 따라 감소하였다. 담수 1kg 생산에 따른 소요 에너지는 응축기 유입 해수온도가 $8^{\circ}C$일 때가 $20^{\circ}C$일 때에 비해 약28.9% 감소하였다.

• 동력기계공학회지
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• 제20권2호
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• pp.91-96
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• 2016

A fleet consists of a main vessel, light vessels and carrying vessels for purse seine fishery. Carrying vessels contains fish storages to maintain freshness of catches. Currently most carrying vessels applies the cooling system using plain ice though accompanied various shortcomings. Seawater cooling system directly chilling seawater are now in use on carrying vessels in some developed countries to make up for these shortcomings and maximize advantages. This research deals with necessity of seawater cooling systems and establishes system criteria using Aspentech HYSYS program, prior to an experiment of compact-scale seawater cooling system which now in progress of manufacture. Performance comparison on condensation capacity, mass flow rate of working fluid, compressor power input, pump power input and others of the seawater cooling system applying a flooded evaporator is conducted with respect to the temperature of surface seawater varying according to seasons. The result presents that mass flow rate circulating the system is increased about 16.7% as the temperature of surface seawater increases. At the same condition, condensation capacity and compressor input work also increase about 9.8% and 91.2%, respectively.

• Journal of Advanced Marine Engineering and Technology
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• 제41권3호
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• pp.197-201
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• 2017

대부분의 어선에서는 포획된 어류를 관리하고 저장하기 위해 얼음 냉각 시스템을 사용한다. 그러나 얼음 냉각 시스템은 작동 시간의 제한뿐만 아니라 적절한 온도와 염분 농도를 유지하는 것이 어려운 단점이 있다. 본 연구의 목적은 어류 운반선의 어창에 적정한 해수온도 유지를 위한 해수 냉각 시스템용 만액식 증발 열전달 특성을 파악하는데 있다. 실험은 냉매의 해수 온도, 유량 및 포화 온도의 변화를 주며 열전달 특성을 파악하였다. 동일 열유속에서 Aluminium-Brass tube가 Copper-Nickel tube 보다 외측 열전달계수가 약 10% 큰 것으로 확인할 수 있었으며, 이를 통해 해수용 열교환기의 전열관으로 Aluminium-Brass를 적용하는 것이 열전달 측면에서 효과적일 것을 확인할 수 있었다. 만액식 단관 열전달계수와 18 kW급 만액식 해수냉각시스템의 총괄열전달계수의 비교를 통해 동일 조건에서는 25%정도 단관의 열전달계수가 큰 값을 나타내었으며, 이러한 결과는 만액식 관군 열교환기의 설계를 위한 중요한 자료가 되리라 판단된다.

• Ocean and Polar Research
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• 제25권4호
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• pp.607-615
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• 2003

Many organisms are known to survive in icy environments. These include both over wintering terrestrial insects and plants as well the marine fish inhabiting high latitudes. The adaptation of these organisms is both a fascinating and important topic in biology. Marine teleosts in particular, can encounter ice-laden seawater that is approximately $1^{\circ}C$ colder than the colligative freezing point of their body fluids. These animals produce a unique group of proteins, the antifreeze proteins (AFPs) or antifreeze glycoproteins (AFGPs) that absorb the ice nuclei and prevent ice crystal growth. Presently, there are at least four different AFP types and one AFGP type that are isolated from a wide variety of fish. Despite their functional similarity, there is no apparent common protein homology or ice-binding motifs among these proteins, except that the surface-surface complementarity between the protein and ice are important for binding. The remarkable diversity of these proteins and their odd phylogenetic distribution would suggest that these proteins might have evolved recently in response to sea level glaciations just 1-2 million years ago in the northern hemisphere and 10-30 million years ago around Antarctica. Winter flounder, Pleuronectes americanus, has been used as a popular model to study the regulation of AFP gene expression. It has a built-in annual cycle of AFP expression controlled negatively by the growth hormone. The signal transduction pathways, transcription factors and promoter elements involved in this process have been studied in our laboratory and these studies will be presented.

• 한국수산과학회지
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• 제50권2호
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• pp.207-218
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• 2017

Seawater with salinity of 32.5 psu or less is observed in the southern Japan/East Sea (JES) every autumn. It is confined to a surface layer 30-45 m in depth that expands to cover the entire JES in October. Two sources of "autumn low-salinity water" have been identified from historical hydrographic data in the western JES: East China Sea (ECS) water mixed with fresh water discharge from the Yangtze River (Changjiang) and seawater diluted with melted sea ice in the northern JES. Low-salinity water inflow from the ECS begins in June and reaches its peak in September. Low-salinity water from the northern JES expands southward along the coast, and its horizontal distribution varies among years. A rare observational study of the entire JES in October 1969 indicated that water with salinity less than 33.0 psu covered the southwestern JES; the lowest salinity water was found near the Ulleung Basin. In October 1995, the vertical distribution of salinity observed in a meridional section revealed that water with salinity of 33.6 psu or less was present in the area north of the subpolar front.

• 한국수산과학회지
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• 제21권3호
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• pp.177-183
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• 1988

정어리를 시료어로 하여 빙장법 및 $-1^{\circ}C$ 냉각해수저장법으로 저장하면서 시료어의 염도, K값,VBN, TMA, POV, TBA, 염용성단백질양, $Ca^{2+}-AT-Pase$ 활성 및 어묵의 물성변화 등을 비교 검토하여 다음과 같은 결과를 얻었다. 1. K값, VBN 및 TMA값을 통한 선도저하의 측면에서 살펴보았을 때 빙장법보다 냉각해수저장법이 선도저하 억제효과가 있음을 나타내었다. 2. POV 및 TBA값에 의한 지질산화 측면에서도 냉각해수저장법이 빙장법보다 지질산화의 억제효과가 있음을 나타내었다. 3. 염용성단백질량 및 $Ca^{2+}ATP$ ase 활성을 측정한 단백질 안정성의 측면에서도 냉각해수저장법이 효과적이었다. 4. 균의 증식억제도 냉각해수저장법에서 효과가 있다. 5. 어묵의 물성변화 즉 절곡시험 젤리강도, 보수력에서도 냉각해수저장법이 빙장법보다 효과가 있었다. 이상과 같이 여러가지 지표를 사용하여 실험한 결과, 냉각해수저장법이 빙장법보다 선도유지방법으로 우수함이 입증되었으므로, 현재 주로 사용되고 있는 빙장법을 냉각해수저장법으로 대치한다면 선도저하 때문에 사료로 이용되는 대부분의 정어리를 통조림 원료로 이용 가능하리라고 생각되므로, 정어리자원의 효율적인 이용면에서 국가적 차원에서 시급히 실용화되어야 할 것으로 생각되며, 이에 대한 기초자료로 활용화되었으면 한다.

• Ocean and Polar Research
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• 제45권3호
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• pp.141-153
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• 2023

Biological pump processes generated by diatom production in the surface water of the Southern Ocean play an important role in exchanging CO₂ gas between the atmosphere and ocean. In this study, the biogenic opal content of the sediments was measured to elucidate the variation in the primary production of diatoms in the surface water of the Southern Ocean since the last glacial period. A piston core (COR-1bPC) was collected from the Conrad Rise, which is located in the Indian sector of the Southern Ocean. The sediments were mainly composed of siliceous ooze, and sediment lightness increased and magnetic susceptibility decreased in an upward direction. The biogenic opal content was low (38.9%) during the last glacial period and high (73.4%) during the Holocene, showing a similar variation to that of Antarctic ice core ΔT and CO₂ concentration. In addition, the variation of biogenic opal content in core COR-1bPC is consistent with previous results reported in the Antarctic Zone, south of the Antarctic Polar Front, in the Southern Ocean. The glacial-interglacial biogenic opal production was influenced by the extent of sea ice coverage and degree of water column stability. During the last glacial period, the diatom production was reduced due to the penetration of light being limited in the euphotic zone by the extended sea ice coverage caused by the lowered seawater temperature. In addition, the formation of a strong thermocline in more extensive areas of sea ice coverage led to stronger water column stability, resulting in reduced diatom production due to the reduction in the supply of nutrient-rich subsurface water caused by a decrease in upwelling intensity. Under such environmental circumstances, diatom productivity decreased in the Antarctic Zone during the last glacial period, but the biogenic opal content increased rapidly under warming conditions with the onset of deglaciation.