• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.3
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• pp.227-233
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• 2005

In order to estimate the effective horse power(EHP) in towing net of a bottom trawl ship, the ship's resistance was calculated by using a series data of Yamagata and Wigley formula. Also the effective horse power for a ship(EHPs) was estimated versus the ship speed in sailing and the propulsive efficiency was calculated with the brake horse power and the effective horse power. Then the effective horse power for a ship and a trawl net were estimated in the application of the propulsive efficiency in towing net. The total effective horse power($EHP_T$) was average 187.6kW and the effective horse power for a 1.awl net($EHP_n$) was average 176.7kW at a smooth sea state in towing net. The ratio of $EHP_n$ to $EHP_T$ was about 94.0% and the value was higher slightly than was already informed at a smooth sea state. The power for keeping up a townet speed was required more about 20% of a maximum continuous power at a rather rough sea state than a smooth sea state. In the future, if the residual resistance is considered with a sea state, $EHP_n$ will be estimated more correctly Also the data of EHP estimated by this method will be used as the basic data to design a trawl net.

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.2
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• pp.53-61
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• 2018

Sargassum fulvellum (gulfweed) is a widespread seaweed in the coastal areas of northeast Asia. In the present study, we identified the phenolic compounds present in aqueous and ethanolic extracts of S. fulvellum and evaluated their antioxidative properties and their abilities to block cell proliferation using in vitro assays: antioxidant activity was assessed by using a DPPH assay and superoxide anion scavenging activity, anti-tyrosinase activity, and anti-proliferative activity were assessed using MTT and lactate dehydrogenase [LDH] assays in vascular smooth muscle cells. The hot-water ($65^{\circ}C$) extract had a higher phenol content than the ethanolic extract. The hot-water extract showed a statistically significant increase in free radical scavenging activity and a greater ability to reduce proliferation of vascular smooth muscle cells stimulated with platelet-derived growth factor-BB. Taken together, hot-water extracts of S. fulvellum may be an important source of antioxidative and antiproliferative agents.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.447-452
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• 2002

An honeycomb/smooth land seal alternating with the honeycomb seal is suggested for structural enhancement in high pressure turbomachinery. Governing equations are derived for an honeycomb/smooth land annular gas seal based on Hirs' lubrication theory and Moody's friction factor model for smooth land and empirical friction factor model for honeycomb land. By using a perturbation analysis and a numerical integration method, the governing equations are solved to yield leakage and the corresponding dynamic coefficients developed by the seal. Theoretical results show that leakage is increasing and rotordynamic stability is decreasing as increasing the length of smooth land part in the honeycomb/smooth land seal.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2E
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• pp.37-42
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• 1995

The polar parabolic equation method (Polar PE) which introduces a series of "cascaded" boundary fitting coordinates into the parabolic equation method has been verified as a good numerical method for atmospheric sound propagation over a curved surface and hills. Polar PE is applied here to underwater sound propagation over a sea mountain assuming locally reacting boundary sea bottom and pressure release water surface for the boundary conditions. Calculations are presented for underwater propagation over a 450 m high sea mountain. Feasibility of Polar PE application for underwater sound propagation over a smooth mountain is discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.809-815
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• 2020

The food components of the muscles and roes of the smooth lumpsucker Aptocyclus ventricosus and korai bikunin Liparis ingens from the East Sea, Korea were determined. The proximate composition of the muscles of the smooth lumpsucker was 88.35%, 8.30%, 2.24%, and 1.08% and that of the korai bikunin was 91.62%, 6.88%, 0.45%, and 1.15% of moisture, protein, lipid, and ash, respectively. The roes of the smooth lumpsucker contained 83.25%, 11.28%, 3.65%, and 1.07% moisture, protein, lipid, and ash, respectively, whereas for korai bikunin, it was 81.53%, 15.09%, 1.97%, and 1.14%, respectively. The prominent fatty acids of the muscles were 16:0, 18:0, 18:1n-9, 18:1n-7, 20:4n-6, 20:5n-3 (eicosapentaenoic acid, EPA), and 22:6n-3 (docosahexenoic acid). The prominent fatty acids of the roes were similar to those of the muscles, although showing a higher ratio of EPA than that of the muscles. The major amino acids in the muscles were glutamic acid, lysine, leucine, and arginine, whereas they were glutamic acid, aspartic acid, leucine, serine, and arginine in the roes.

• Smart Structures and Systems
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• v.23 no.2
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• pp.185-194
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• 2019

The probabilistic tsunami risk assessment of large coastal areas is challenging because the inland propagation of a tsunami wave requires an accurate numerical model that takes into account the interaction between the ground, the infrastructures, and the wave itself. Classic mesh-based methods face many challenges in the propagation of a tsunami wave inland due to their ever-moving boundary conditions. In alternative, mesh-less based methods can be used, but they require too much computational power in the far-field. This study proposes a hybrid approach. A mesh-based method propagates the tsunami wave from the far-field to the near-field, where the influence of the sea floor is negligible, and a mesh-less based method, smooth particle hydrodynamic, propagates the wave onto the coast and inland, and takes into account the wave structure interaction. Nowadays, this can be done because the advent of general purpose GPUs made mesh-less methods computationally affordable. The method is used to simulate the inland propagation of the 2004 Indian Ocean tsunami off the coast of Indonesia.

• Economic and Environmental Geology
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• v.28 no.2
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• pp.155-164
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• 1995

The kriging model, one of the geostatistical models, has been used to evaluate the deep-sea manganese nodule deposits until now. The distribution of the manganese nodule deposits estimated by the model shows the smooth surface as well as much difference from the actual distribution. Subsequently, it estimates the deposit distribution roughly in terms of the limited data of surveyed zone. Therefore, this paper presents the interpretation methodology of the deep-sea manganese nodule deposit distribution by using the fractal model to overcome the problems caused by the geostatistical model. Also, the manganese nodule distributions are interpreted by using the manganese nodule data sampled in the GH82-4 zone, west longitude $165^{\circ}40^{\prime}-169^{\circ}00^{\prime}$, and south latitude $0^{\circ}00^{\prime}-2^{\circ}40^{\prime}$ neighboring Nova-Canton Trough in the Pacific Ocean which was surveyed by the Geological Survey of Japan in 1982.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.335-343
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• 2019

Overtopping discharge for sea dike having low mound and high wave wall (LMHW sea dike) is investigated with hydraulic experiments in this study. Vertical, Flare and Bullnose type wave walls are selected and Tetrapods (double layer) and Accropode (one layer) are adopted for armour layers of the front slope. The results of the hydraulic experiments are compared to the overtopping formulas for armoured rubble slopes and vertical sea dikes suggested by EurOtop Manual. Predicted overtopping discharges are underestimated as the roughness efficiency factors (γ_f) of armour blocks suggested by EurOtop are adopted when the overtopping formula for armoured rubble slopes sea dike is used. Meanwhile the predicted overtopping discharges agree well with the hydraulic experiments when the modified roughness efficiency factors redefined by multiplying efficiency factor of the heights of armoured crest berm and wave wall (γ_AR) are adopted. Return wall effects on a vertical wall (Kortenhaus et al., 2003; Pearson et al., 2004a) and the effects on a smooth dike slope (Van Doorslaer et al., 2015) in EurOtop Manual are investigated for Flare and Bullnose type wave walls. As a results of the comparison between experimental results and 2 formulas, return wall effect on a smooth dike was more valid for LMHW sea dike.

• The Journal of Engineering Geology
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• v.32 no.2
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• pp.271-280
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• 2022

Landfast sea ice forms near coastlines in polar regions. Continuous monitoring of this sea ice is important, as it plays a key role in the marine ecosystem and affects the operation of nearby research stations. This study detected landfast sea ice around Jang Bogo research station in East Antarctica by stacking interferometric coherence images of Sentinel-1 synthetic aperture radar (SAR) data with 6-, 12- and 18-day temporal baselines. A total of 50 landfast sea ice maps were generated covering July 2017 to June 2018. The time series revealed regional differences in the timing of the maximum extent as well as growth rate of landfast sea ice. Overall, detecting landfast sea ice using interferometric SAR coherence seems promisingly feasible; however, limitations remain owing to low backscattering coefficients from new and smooth sea ice surfaces and subtle movements of sea ice in contact with the Campbell Glacier Tongue.

• Journal of Veterinary Clinics
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• v.31 no.2
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• pp.156-158
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• 2014

Malassezia spp. was isolated from the skin lesion of a South American Sea Lion (Otaria byronia) in South Korea. Colonies were cream to yellowish with smooth margin on Sabouraud dextrose agar without lipid supplements. Yeast cells were ovoid to cylindrical in shape and budding daughter cells from broad base. We conducted 26s rRNA sequencing to specify the strain of the yeast and found out this isolate highly matched with Malassezia pachydermatis isolated from canine otitis. The pulse therapy of oral itraconazole was very effective in this case. M. pachydermatis has a wide range of host animals but this is the first report in a sea lion in South Korea.