• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.6
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• pp.247-257
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• 2022

In order to investigate the generations of rip currents modulated with the tidal elevations at a mega-tidal beach at the West Sea coast, numerical simulations of rip currents over the topography of the Daecheon beach were performed by using a Boussinesq-type wave and current model, FUNWAVE. The mega-tidal coast includes rocky outcrops (i.e., reefs) lying over or under the water surface according to the tidal elevations in the offshore and nearshore bathymetry. The offshore topographically-controlled rip currents were well reproduced due to the alongshore non-uniformities transformed by the tide-modulated topography. This study addressed the generation types of rip currents to occur at the mega-tidal coast with the tide-modulated outcrops and reefs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2872-2878
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• 2011

In spite of high concentrations of SS(>30mg/l) in July 2010, the water condition of Manripo was fine for swimming as COD data lower than 2.0mg/l in summer continuously. The bloom of phytoplankton or red tide were not occurred in the waters. COD data from the waters of Daechon were lower than 2.0mg/l, except August. Relatively high SS concentrations were the characteristics of Daechon beach and were caused by the effects of mud resuspension. The dominant taxa of phytoplnkton communities were consist of diatoms as the normal groups of neritic sea waters.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.303-305
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• 2011

2010년 여름철 만리포의 수질은 COD가 지속적으로 2.0 mg/l 이하로 측정되어 양호한 상태였고 SS(부유물질)의 량이 7월 조사에서 30mg/l를 초과하였으나 해수욕에는 무리가 없었을 것으로 판단된다. 식물플랑크톤은 대발생이나 적조 등의 현상이 나타나지 않았다. 대천의 수질은 8월 조사에서 COD값이 평균 2.0mg/l를 초과하기도 하였으나 하절기 정반적으로는 2.0mg/l 이하로 나타나 역시 해수욕장 수질로서는 양호하다. 식물플랑크톤 역시 규조류가 우점하는 보편적인 해수의 특징을 보였다.

• The Journal of the Petrological Society of Korea
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• v.17 no.1
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• pp.1-15
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• 2008

The metasedimentary rocks of the Nampo Croup consisting of metaconglomerates, metasandstones, phyllites are exposed in the area of the Daechcon beach and Maryangri, Seocheon-gun. Their typical metamorphic assemblages of Bt-Mus-Grt-Qtz (${\pm}Pl{\pm}Chl$) and Bt-Mus-Qtz (${\pm}Pl{\pm}Chl$) indicate that they have been under intermediate P/T type metamorphism and were metamorphosed to garnet zone grade of amphibolite-facies during the Daebo Orogeny. Pressure-temperature conditions of peak metamorphism estimated from geothermobarometries are $560{\sim}595^{\circ}C$, $6.9{\sim}8.2\;kb$ respectively. The results of K-Ar biotite age determination are $143.2{\pm}3.6\;Ma$, $122.6{\pm}2.4\;Ma$ and $124.8{\pm}2.4\;Ma$ and the last two ages are considered as the results of later-stage thermal perturbation. On the bases of the formation age of Daedong Supergroup of $187{\sim}172\;Ma$ (Han et al., 2006; Jeon et al., 2007) combined with the results of this study, the hypothetical model of tectonometamorphic evolution of the study area during Daebo Orogeny is proposed. Crustal thickening resulted from folding and duplexing of thrusts in the area initiated at around 175 Ma just after sedimentation of Nampo Croup. And then rapid cooling by normal faulting due to crustal extention followed immediately after the peak metamorphism to the closure temperature of biotite.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.9-11
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• 2014

As Daecheon beach, which is the study area, has problem of erosion and loss of most beach under the extraordinary wave during the typhoon event, it is necessary to apply erosion control measures for short term impact. Therefore, we analyzed the status and reason of the erosion by field survey, collection of hydraulic model test, and numerical model experiment. For the erosion control measure, we adopted beach feeding and submerged reef method available at that site among various counter measures. Numerical analyses were made for both beach feeding only and beach feeding with submerged reefs and these were compared with the present status to find out the optimum design and to contribute for preparing a long term plan of beach loss protection.

• 한국해양학회지
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• v.25 no.3
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• pp.135-144
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• 1990

Fish assemblage occupying the surf zone habitat of Taecheon sand beach in Cheonsu Bay was analyzed using monthly samples collected by a beach seine from September 1984 through August 1985. During each sampling period five hauls were completed, one at each 2-hour interval during the spring tide. Of 35 species identified, Favonigobius gymnauchen, Sillago japonica, Konosirus punctatus, Sardinella zunasi and chaenogobius mororana accounted for 79% of the individuals collected, and F. gymnauchen, s. japonica, K. punctatus, S. zunasi and Kareius bicoloratus constituted 67% of the biomass obtained. Overall abundance in terms of numbers and in biomass were 0.13 individuals/m$^2$ and 0.33g/m$^2$, respectively. A larger number of individuals and greater biomass was observed during the warmer months showing significant correlation with water temperature. High abundance of June was related to the occurrence of adult F. gymnauchen. A large number of individuals and great biomass was collected in August and September, a period of high abundance in juveniles of the seasonal species such as S. japonica, K. punctatus and S. zunasi. Temperature and habitat occupation according to life history of the dominant species might be the primary factors of the marked seasonality of the surf zone fish populations in the study area.

• Journal of Mushroom
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• v.8 no.3
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• pp.122-130
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• 2010

Common mushroom production per area has been decreased and are up to less than 50% of the 1980 production. To determine the main reasons for the decrement, we performed this study. Two main reasons, which are mushroom disease and the low compost quality because of mechanized compost making, were assessed. In mechanized mushroom farms, nitrogen concentration in compost was lower than recommended and total compost quantity was about 100-150 $kg/3.3m^2$, which was also lower than usual. Our study revealed that higher nitrogen concentration (about 1.5%) in compost gave better production. Also, use of large amount of compost appeared to increase the mushroom production, although more insects and disease problems were observed. The relationships between the presences of microorganisms and occurrence of diseases were assessed by monitoring the microorganism densities near the mushroom farms. Higher number of microorganisms were observed near the mushroom farm area, compared to control region, Daechon beach. Most contaminating molds were found in the circulating fans, tunnel and culture room floor. The bacterial isolates were collected from the air in mushroom culture room and killed with 0.005% Benzalkonium solution, indicating treatment of Benzalkonium are the effective methods to sanitize the mushroom culture room.