• The Korean Journal of Physiology and Pharmacology
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• 제24권4호
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• pp.349-362
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• 2020

Temperature affects the firing pattern and electrical activity of neurons in animals, eliciting diverse responses depending on neuronal cell type. However, the mechanisms underlying such diverse responses are not well understood. In the present study, we performed in vitro recording of abdominal ganglia cells of Aplysia juliana, and analyzed their burst firing patterns. We identified atypical bursting patterns dependent on temperature that were totally different from classical bursting patterns observed in R15 neurons of A. juliana. We classified these abnormal bursting patterns into type 1 and type 2; type 1 abnormal single bursts are composed of two kinds of spikes with a long interspike interval (ISI) followed by short ISI regular firing, while type 2 abnormal single bursts are composed of complex multiplets. To investigate the mechanism underlying the temperature dependence of abnormal bursting, we employed simulations using a modified Plant model and determined that the temperature dependence of type 2 abnormal bursting is related to temperature-dependent scaling factors and activation or inactivation of potassium or sodium channels.

• 수산해양기술연구
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• 제57권2호
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• pp.93-106
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• 2021

Changes in the fishing grounds for four drag-bagnet fisheries (large trawl, large pair trawl, large Danish seine and middle Danish seine) were investigated by year and sea-blocks in Korean waters. We used catch and effort data by sea-block (latitude × longitude: 30' × 30') of the National Institute of Fisheries Science (NIFS) and yearly fishing production statistics of the Korean statistic information service from 2008 to 2014. The main benthic habitat of fishing ground was sand and sandy mud material. The average swept areas for the four fisheries were 181.7 km², 606.4 km², 2,720.9 km² and 252.8 km², respectively. The main fishing ground was around Jeju Island and the eastern South Sea. The main fishing ground moved to the northern part of the South Sea during the study period due to a closure of fishing grounds and changes in the target species.

• ALGAE
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• 제37권4호
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• pp.265-279
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• 2022

The primary production (PP) by phytoplankton in marine ecosystems is essential for carbon cycling and fueling food webs. Hence, estimating the PP in the territorial sea of each country is a necessary step to achieving carbon neutrality. To estimate the PP in the territorial sea of the Republic of Korea from 2005 to 2021, we analyzed various physiochemical parameters, such as sea surface temperature (SST), Secchi depth, and concentrations of chlorophyll-a and nutrients in the seas of five regions, including the East Sea, West Sea, western South Sea, eastern South Sea, and the waters off Jeju Island. During the 17-year study period, the SST tended to increase, while the nutrient concentrations declined, except in the Jeju area. Overall, the PP did not show a specific temporal trend, but daily PP in the western South Sea was the highest among the five regions. Moreover, the maximum PP in the Korean territorial waters (76,450 km²) was estimated at 11,227 Gg C y^-1, which accounts for 0.03% of the global PP. The results may give insights into a better understanding of the PP, further resource utilization, and environmental sustainability in the studied region.

• 한국환경생태학회지
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• 제36권6호
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• pp.627-638
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• 2022

본 연구는 제주도 연안의 해역별 해조류 분포특성을 비교하기 위하여 2018년 5월부터 12월까지 제주도 본섬 4개 정점과 유인도서 2개 정점의 마을어장에서 수행되었다. 해조류는 총 101종으로 녹조류 13종(12.9%), 갈조류 24종(23.8%) 그리고 홍조류 64종(63.4%)이 출현하였다. 계절별로는 5월에 가장 많은 해조류가 출현하고, 10월에 가장 적게 출현하는 전형적인 온대해역의 특징을 나타냈다. 수심별 해조류 출현 종수는 5m와 8m에서는 66종과 65종으로 유사하였으며, 12m에서는 74종으로 최대였다. 해역별로는 도서해역인 우도에서 66종으로 가장 많은 해조류가 출현하였고, 본섬의 동부 표선에서 27종으로 가장 적게 출현하였다. 출현종 가운데 중요도가 높은 해조류는 감태(Ecklonia cava)와 둘레혹산호말(Corallina crassissima)로 각각 21.1%와 20.3%를 나타냈으며, 방황혹산호말(Corallina aberrans) 9.2%, 에페드라게발(Amphiroa ephedraea) 6.2% 그리고 큰열매모자반(Sargassum macrocarpum) 4.4%의 중요도를 나타냈다. 해조류 중 산호말류는 평균 11.2종이 출현하였고, 각 해역의 산호말류 중요도는 평균 32.6%로 우도에서 14.7%로 가장 낮았고, 표선에서 가장 높은 41.0%를 차지하였다. 해조류 군락의 생태학적 평가지수(EEI)는 2.1~10.0으로 표선의 5월과 6월 12m에서 가장 낮았고, 그 밖의 다른 해역에서는 평균 7.3이상으로 좋은 상태를 나타냈다. 본 조사에서 설정한 생태등급기준 I 등급은 우도와 추자도의 수심 12m이었으며, II 등급은 사계와 추자도의 수심 5 m와 8 m가 해당되었다. III 등급은 표선과 귀덕2의 수심 5m와 12m, 평대의 수심 5m와 8m가 해당되었으며, IV 등급은 귀덕2의 수심 8m가 해당되었다.

• 한국광물학회:학술대회논문집
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• 한국광물학회.한국암석학회 2001년도 공동학술발표회 논문집
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• pp.75-75
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• 2001

We report Sr, Nd and Pb isotope data of clinopyroxene separates from ultramafic xenoliths and their host basaltic rocks in Jeju Island, Baekryeong Island, Boeun and Ganseong, Korea. The isotopic data of the xenoliths and host basalts are distinctly different from those of Korean basement rocks. Except for two xenoliths from Ganseong, all samples in this study have isotopic ratios within the combined range of MORB-OIB data. All basaltic rocks have Nd-Sr-Pb isotope compositions different from those of xenoliths, indicating that the host basaltic magma did not derive from the lithospheric mantle where the xenoliths originated. The range of isotopic composition of xenoliths is much greater than that observed in host basalts, which reflects small-scale heterogeneity of the lithospheric mantle. The greater isotopic heterogeneity of the lithospheric mantle probably reflects its long-term stability. The spinel peridotite xenolith data of Jeju Island, Baekryeong Island and Boeun display mixing hyperbolas between DMM and EM II end members. Since Jeju basalts have EM II-like isotopic signature, the mixing relationship shown by the isotopic data of the Jeju xenoliths can be interpreted as the result of infiltration of metasomatic fluid or melt derived from basaltic magma into DMM-like lithospheric mantle. In contrast to other xenolith sites, the Ganseong xenoliths are dominantly clinopyroxene megacryst and pyroxenite. Clinopyroxene megacrysts have different isotopic ratios from their host basalt, reflecting its exotic origin. Two Ganseong xenoliths (wherlite and clinopyroxenite) have much enriched Sr and Nd isotopic ratios and Nd model ages of 2.5-2.9 Ga, and plot in an array away from the MORB-OIB field. The mantle xenoliths from Korean Peninsula have similar $\^$87/Sr/$\^$86/Sr,$\^$143/Nd/$\^$144/Nd and $\^$207/Pb/$\^$204/Pb ratios to, but higher $\^$208/Pb/$\^$204/Pb ratios than, those from eastern China, indicating that Korean xenoliths are derived from the lithospheric mantle with higher Th/U ratio compared with Chinese ones. The isotopic data of xenolith-bearing basalts of Baekryeong Island and Ganseong, along with Ulreung and Dok Islands, show a mixing trend betlveen DMM and EM I in Sr-Nd-Pb isotopic correlation diagrams, which is also observed in tile northeastern Chinese basalts. However, the Jeju volcanic rocks show an EM II signature that is observed in southeastern Chinese basalts. The isotopic variations in volcanic rocks from the northern and southern portions of the East Asia reflect a large-scale isotopic heterogeneity in their source mantle.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 제7회 특별심포지움 논문집
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• pp.55-71
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• 2005

현무암으로 구성된 제주도에서 다양한 물리검층 수행하여 용암분출에 따른 물성변화 특성 및 동부지역에서 광범위한 해수침투대의 특성을 파악하고자 하였다. 제주도는 해안가를 따라서 해수침투 관측망을 구축, 운영하고 있으며 지하수자원의 평가와 이와 관련된 지질특성 파악 목적으로 다양한 조사와 모니터링을 수행하고 있다. 제주도의 29개 해수침투 관측정에서 방사능검층(자연감마선, 중성자검층 및 감마-감마(밀도)검층), 전기검층, 공경검층, 공내수의 온도/전기전도도검층, 유향유속검층 등을 수행하였다. 포화대 구간에 대한 물리검층 자료는 현무암 지질 특성을 잘 반영하였으며 일관성 있는 결과를 나타냈다. 자연감마선검층은 포화/불포화대 구간에 관계없이 퇴적층, 미고결 U층, 서귀포층에서 높은 값을 보였으며 중성자검층은 용암의 분출과 관련된 특성 파악에 효과적이었다. 수중화산쇄설성퇴적층은 높은 공극률, 낮은 전기비저항을 나타내며 주요 지하수의 유동통로로 해석되었다. 침상현무암은 높은 전기비저항과 넓은 범위의 공극률을 보이고 퇴적층과 U층은 낮은 전기비저항, 높은 공극률을 보인다. 동부지역의 온도검층 자료는 수문학적인 해석이 유용하며 수산지역의 해수침투 특성의 해석에도 이용되었다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.91-91
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• 2019

Hibiscus syriacus L. is widely distributed throughout Eastern and Southern Asia and its root bark has been used as a traditional remedy. Recently, the extracts of H. syriacus L. exerts anti-cancerous, anti-microbial, and anti-inflammatory activities. However, the effect of anthocyanin-rich fraction of H. syriacus L. petals (PS) has not been studied under excessive oxidative stress. In this study, we evaluated the cellular protective effect of PS in HaCaT human skin keratinocytes under hydrogen peroxide ($H_2O_2$)-induced oxidative stress conditions. PS at below $400{\mu}g/ml$ did not show any cell death; however, over $800{\mu}g/ml$ of PS gradually increased cell death. PS at below $400{\mu}g/ml$ significantly inhibited $H_2O_2$-induced apoptosis in HaCaT cells concomitant with downregulation of Bax and upregulation of pro-PARP and p-Bcl-2. Additionally, PS remarkably reversed $H_2O_2$-induced excessive reactive oxygen species (ROS) production and apoptosis, and also significantly inhibited mitochondrial ROS production concomitant with suppression of $H_2O_2$-induced mitochondrial depolarization. $H_2O_2$-mediated ratio of Bax to Bcl-2, and caspase-3 activation were markedly abolished in the presence of PS. Moreover, the inhibition of HO-1 function using zinc protoporphyrin, an HO-1 inhibitor, significantly attenuated the cellular protective effects of PS against $H_2O_2$, indicating the significance of HO-1 in PS mediated cytoprotective effect, which was mediated by activating nuclear factor erythroid 2-related factor-2 (Nrf2). Taken together, our results suggest that cytoprotective effect of PS in HaCaT keratinocytes against oxidative stress-induced apoptosis is mediated by inhibiting cellular and mitochondrial ROS production, which is downregulated by activating Nrf2/HO-1 axis.

• 한국토양비료학회지
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• 제8권3호
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• pp.121-133
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• 1975

1. 제주도(濟州道) 전토양(田土壤)은 육지(陸地)에 비(比)하여 PH 가 높고 유기물(有機物)과 염기(鹽基)의 함량(含量)이 높으나 유효인산(有效燐酸)의 함량(含量)만은 현저(顯著)히 낮다. 한편 남제주(南濟州) 전토양(田土壤) (91점(點))의 pH 및 유기물(有機物)과 유효인산(有效燐酸)의 함량(含量)은 각각(各各) 6.1, 13%, 23ppm이고 북제주(北濟州) 전토양(田土壤)은 각각(各各) 6.4, 3.7%, 76ppm이다. 2. 제주도(濟州道) 전토양(田土壤)은 토양비옥도(土壤肥沃度)의 면(面)에서 볼때 흑색토(黑色土), 농암갈색토(濃暗褐色土) 그리고 암갈색토(暗褐色土) 및 적황색토(赤黃色土)로 분류(分類)될 수 있다. 3. 토양유기물(土壤有機物)의 함량(含量)은 흑색토(黑色土)(15%)>농암갈색토(濃暗褐色土)(7%)>암갈색(暗褐色) (3%)의 순(順)이며 유기물함량(有機物含量)이 높은 토양(土壤)일수록 인산흡수계수(燐酸吸收係數)가 높고 유효인산함량(有效燐酸含量)이 낮다. 한편 유기물함량(有機物含量)이 높은 토양(土壤)은 염기치환용량(鹽基置換容量)이 크나 염기(鹽基)의 함량(含量)이 적어서 염기포화도(鹽基飽和度)는 낮다. 4. 대맥(大麥)의 지역별(地域別) 수량(收量)을 보면 북제주(北濟州)가 남제주(南濟州)보다 높고 서부(西部)가 동부지역(東部地域)보다 높으며 토양종류별(土壤種類別)로는 암갈색토(暗褐色土)>농암갈색토(濃暗褐色土)>흑색토(黑色土)의 순(順)이다. 5. 감자와 고구마의 생산력(生産力)은 육지(陸地)보다도 제주도(濟州道)에서 높은데 이들은 반토성(礬土性)에 강(强)한 작물(作物)이라고 생각된다. 화산회토양(火山灰土壤)에서는 내(耐)알루미늄성(性)의 작물(作物)이나 품종(品種)의 선택(選擇)이 중요(重要)하다. 6. 제주도(濟州道)에서의 3요소(要素)의 비효(肥效)를 보면 육지토양(陸地土壤)에 비(比)하여 고구마는 3요소(要素)의 비효(肥效)가 모두 낮으나 동작물(冬作物)인 대맥(大麥)과 유채(油菜)는 질소(窒素)와 인산(燐酸)의 비효(肥效)가 높으며 특(特)히 질소(窒素)의 비효(肥效)가 높다. 한편 남제주(南濟州) 토양(土壤)이 북제주(北濟州)에 비(比)하여 3요소(要素)의 비효(比效)가 높다. 7. 생산력(生産力)이 낮은 화산회토양(火山灰土壤)의 개량(改良)을 위(爲)하여는 매우 많은 양(量)의 석회(石灰)를 요구(要求)하나 석회(石灰)를 일시에 다량시용(多量施用)하는 것은 양분(養分)의 균형(均衡)을 악화(惡化)시킬 우려가 있으므로 석회적량(石灰適量)을 수작기(數作期)에 걸쳐 나누어주거나 고토(苦土) 및 가리(加里)의 증시(增施) 및 퇴비(堆肥)와 함께 주는 것이 바람직하다. 8. 화산회토양(火山灰土壤)에서는 시용인산(施用燐酸)의 대부분(大部分)이 불가급태(不可給態)로 되여 유효화비율(有效化比率)이 낮으므로 인산(燐酸) 30~40kg/10a 정도(程渡)의 시용량(施用量)으로는 그 비효(肥效)가 극(極)히 적으며 최대수량(最大收量)을 얻기 위(爲)한 인산시용량(燐酸施用量)은 300~400kg/10a 달(達)하는 것으로 추정(推定)된다. 한편 인산(燐酸)의 효과(效果)도 유기질비료(有機質肥料)를 병용(倂用)하는 조건(條件)에서 더욱 크다.

• 한국환경과학회지
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• 제29권3호
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• pp.257-272
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• 2020

This study investigates the temporal and spatial variations of marine meterological elements (air temperature (Temp), Sea Surface Temperature (SST), and Significant Wave Height (SWH)) in seven coastal waters of South Korea, using hourly data observed at marine meteorological buoys (10 sites), Automatic Weather System on lighthouse (lighthouse AWS) (9 sites), and AWS (20 sites) during 2013-2017. We also compared the characteristics of Temp, SST, and air-sea temperature difference (Temp-SST) between sea fog and non-sea-fog events. In general, annual mean values of Temp and SST in most of the coastal waters were highest (especially in the southern part of Jeju Island) in 2016, due to heat waves, and lowest (especially in the middle of the West Sea) in 2013 or 2014. The SWH did not vary significantly by year. Wind patterns varied according to coastal waters, but their yearly variations for each coastal water were similar. The maximum monthly/seasonal mean values of Temp and SST occurred in summer (especially in August), and the minimum values in winter (January for Temp and February for SST). Monthly/seasonal mean SWH was highest in winter (especially in December) and lowest in summer (June), while the monthly/seasonal variations in wind speed over most of the coastal waters (except for the southern part of Jeju Island) were similar to those of SWH. In addition, sea fog during spring and summer was likely to be in the form of advection fog, possibly because of the high Temp and low SST (especially clear SST cooling in the eastern part of South Sea in summer), while autumn sea fog varied between different coastal waters (either advection fog or steam fog). The SST (and Temp-SST) during sea fog events in all coastal waters was lower (and more variable) than during non-sea-fog events, and was up to -5.7℃ for SST (up to 5.8℃ for Temp-SST).

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.185.1-185.1
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• 2010

The 3MW OWEC demonstrator project in Korea will be the first offshore wind project with Korean turbine, Doosan WinDS3000, and constructed on the north-eastern sea of Jeju Island as the water depth of 15m. Integrated loadings of wind and wave are investigated to describe a design loads for both extreme and fatigue conditions using GH-Bladed. A dynamic behaviour of substructure strongly affects a substructure loadings. The jacket structure is designed in accordance with DNV guidelines. The results of this paper show overall design process of offshore substructure as a complex jacket concept and this design process can be implemented on a design of monopile and tripod structures.