• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.328-336
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• 2007

A piston core (587 cm long) was recovered from the upper slope of a seamount in the Korea Plateau. Three episodes of sedimentation were identified based on sedimentary facies, grain size distribution, carbonate constituents and initial $^{87}Sr/^{86}Sr$ ratio of carbonates. The lower part of the core, Unit I-a (core depth $465{\sim}587cm$) is composed of shallow marine carbonate sediments the deposited by storm surges, and is about $13{\sim}15Ma$ (Middle Miocene) based on $^{87}Sr/^{86}Sr$ initial ratio. This suggests that the depositional environment was relatively shallow enough to be influenced by storm activities. Unit I-b (core depth $431{\sim}465cm$) is mostly composed of turbidites, and Sr isotope ages of bivalves and planktonic formaminifera are about $11{\sim}14\;and\;6{\sim}13Ma$, respectively. This indicates that the Korea Plateau maintained shallow water condition until 11 Ma, and began to subside since then. However, planktonic foraminifera were deposited after 11 Ma and redeposited as turbidites as a mixture of planktonic foraminifera and older shallow marine carbonates about 6 Ma ago. Unit II (core depth $0{\sim}431cm$) is composed of pelagic sediments, and the Sr isotope age is younger than 1 Ma, thus the time gap is about 5 Ma at the unconformity. About 1 Ma ago, the Korea Plateau subsided down to a water depth of about 600 m. The sampling locality was intermittently influenced by debris flows and/or turbidity currents along the slope, resulting the deposition of re-transported coarse shallow marine and volcaniclastic sediments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.219-225
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• 2004

Following a preceding study if Shin et al.(2004), wave fields for a month if September if 2003 are simulated based on the modified WAM cycle 4 model that enables the precise wave hindcasting with fine spatial meshes, and characteristics of extreme waves at the south roast if Koreo are analyzed The accuracy if applied wave model is verified by comparing computed wave parameters and corresponding ones measured at Ieodo ocean research station. The wave hindasting if typhoon 'Maemi' with an hour time interval reveals the extreme wave characteristics at 4 primary locations if south coast of Korea as follows: 1) At the front sea of Chaguido in the south of Jeju-do, the maximum significant wave height, moon wave period and mean wave direction appear to be 7.41m, 13.65s and $6.4^{\circ}$, respectively at 16:00 KST if Sep. 12, 2003. 2) At the entrance of Masan Bay, 12.50m, 13.65s and $1.2^{\circ}$ at 21:00 KST if Sep. 12. 3) At the front sea of Suyoung Bay, 13.85m, 13.81s and $0.2^{\circ}$ at 22;00 KST if Sep. 12. 4) At the front sea of Ulsan port, 11.00m, 13.25s and $28^{\circ}$ at 23:00 KST if Sep.

• Korean journal of applied entomology
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• v.52 no.2
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• pp.93-100
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• 2013

In this study, the distribution of Cantao ocellatus in Korea occurred at Jindo, Tongyoung, Gwangju and Taean including Jejudo in 2012 and was coincidentally in accordance with the distribution of Mallotus japonicus as a host plant. The adult emerges in M. japonicus occur from late June to early July and can be observed until the end of October. The investigation of the female and male was measured, developmental characteristics, host plant and oviposition preference under the conditions of temperature $25^{\circ}C({\pm}2)$, humidity 65%(${\pm}2$), day length 16L:8D, by indoor breeding. For females and males respectively, average body lengths were 26.20 mm and 23.88 mm, body widths 11.35 mm and 10.57 mm, head widths 3.84 mm and 3.64 mm, probosics lengths 7.90 mm and 7.27 mm, antennal lengths 9.87 mm and 9.69 mm, anterior leg lengths 12.50 mm and 12.27 mm, intermediate leg lengths 14.61 mm and 13.12 mm, posterior leg lengths 16.90 mm and 16.53 mm, and fresh weights 0.46 g and 0.31 g. It was seen that two kinds of C. ocellatus had prickles at the end of the pronotum which had developed in the fifth instars. The female is distinguished from the male by the reproductive organ and the spotted pattern on the abdominal segment. The preference of drinks was fruit, leafstalk, midrib, and branch in Mallotus japonicus (Thunb.) Muell. Arg., Mallotus japonicus 'Variegatus', Ricinus communis L., Lonicera japonicus var. repens (Siebold) Rehder, Citrus sinensis (L.) Osbeck and Zelkova serrata (Thunb.) Makino.

• Korean Journal of Plant Taxonomy
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• v.31 no.4
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• pp.311-319
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• 2001

In order to evaluate taxonomic status of Latcuca hallaisanensis H. $L{\acute{e}}v$., an endemic species of the Jeju-do Island, we investigated fruit wall structure and chromosome morphology. The fruit wall structure had 10-11 obtuse costae in the transverse section. The costa was wholly occupied by libriform fiber cells, and the underlying fibersclereid tissue was only one to three cells layers thick. Also, the intercosta lacked fiber-sclereid layers. Somatic chromosome numbers and karyotype of Latcuca hallaisanensis were recorded for the first time. This diploid species (2n=10) with the same basic number of x=5 has the total chromosome length $23.3{\mu}m$ and the length of each chromosome falls in $1.9{\mu}m-2.9{\mu}m$. It possess the karyotype complement i.e., 3sm+2st and a characteristic chromosome pair (No. 1 and 2) with a secondary constriction at the distal portion of the short arms. The overall similarity in external morphology (involucre, achene etc), chromosome morphology as well as in fruit wall anatomy between Lactuca hallaisanensis and Crepidiastrum s. lat. clearly indicated that this species should be treated as Crepidiastrum, rather than Lactuca.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.172-177
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• 2016

The phenolic compounds, antioxidant activity and neuronal cell protective effect of Cirsium japonicum extract were evaluated in this study. High performance liquid chromatography mass analysis showed that C. japonicum was composed of chlorogenic acid, linarin, and pectolinarin. C. japonicum extract showed its antioxidant activity with half-maximal inhibitory concentrations of 567 and $130{\mu}g/mL$ by DPPH and ABTS radical scavenging activity, respectively. The total antioxidant capacities of C. japonicum via DPPH, ABTS, and FRAP assays were 11.32, 100.15, and $12.76{\mu}g/mL$ trolox equivalents, respectively. In addition, the neuroprotective effect of C. japonicum extract was investigated by measuring cell viability via MTT, LDH and DCF-DA assay using $H_2O_2-damaged$ PC12 cells. C. japonicum extract showed neuronal cell protective effects in a dose-dependent manner. These results indicated that C. japonicum extract has potent antioxidant and neuronal protective effects. Therefore, C. japonicum can be regarded as an effective and safe functional food resource as natural antioxidants, and may decrease the risk of neurodegenerative disorders.

• Journal of Life Science
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• v.28 no.3
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• pp.361-368
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• 2018

This study investigated the diversity of communities of intestinal microorganisms, separated from the intestinal organs of Red tilefish (Branchiostegus japonicas), collected on the Jeju Coast. First, in the isolation of 1.5% BHIA, MA, TSA and R2A Agar on the medium, there were most colonies in 1.5% BHIA. The results of aerobic culture and anaerobic culture were $1.7{\times}10^6CFU/g^{-1}$ and $1.1{\times}10^5cfu/g^{-1}$, respectively, on average, and 147 pure colonies were separated in total. In 16S rDNA sequencing, there were 58 genera and 74 species, showing 95-100% similarity with the basic strain. They were divided broadly into 5 phyla, and as the main phyletic group, Proteobacteria phylum comprised 50% with 9 families, 35 genera and 35 species of Moraxellaceae, Rhodobacteraceae, Shewanellae, Halomondaceae, Enterobacteriaceae, Vibrionaceae, Hahellaceae, Pseudomonadaceae, and Erythrobacteraceae, with the highest index of dominance. Actinobacteria phylum comprised 24% with 8 families, 11 genera and 17 species of Microbacteriaceae, Intrasporangiaceae, Dietziaceae, Dermabacteraceae, Dermacoccaceae, Nocardiodaceae, Brevibacteriaceae and Propionobacteriacea; Firmicutes phylum, 16% with 6 families, 8 genera and 17 species of Bacillaceae, Staphylcoccaceae, Planococcaceae, Streptococcaceae, Paenibacillaceae and Clostridiaceae; Bacteroidetes phylum, 6% with 2 families, 3 genera and 4 species of Cyclobacteriaceae and Flavobacteriaceae; and Deinococcus-Thermus phylum, 4% with 1 family, 1 genus and 1 species of Deinococcaceae.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.1
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• pp.62-67
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• 1999

As a basic experiment to enhance the symbiotic utility of atmospheric nitrogen on soybean, host affinities and serological distribution of Bradyrhizobium japonicum indigenous to five Korean upland soils were measured. Based on nodulation, the symbiotic affinities between indigenous B, japonicum and eight soybean cultivars were remarkably different among soil inocula. On the whole, the averaged affinities of B. japonicum populations to soybeans were favorable in order of Goseong > Milyang > Suweon soils, but those in Iksan and Namjeju soils were not, especially for Danweonkong, Jangkyeongkong, and Eunhakong soybean cultivars. Regression analyses between nodules mass and shoot dry weight of soybean yielded model with $R^2=0.51$ for Goseong, $R^2=0.45$ for Milyang, $R^2=0.38$ for Iksan, $R^2=0.28$ for Namjeju, and $R^2=0.24$ for Suweon soils. B. japonicum from sampled soils were serologically fell into more than seven serogroups such as YCK 117(34.1%), YCK 141(6.5%), YCK 321(6.5%), YCK 445(4.7%), YCK 338(2.9%), YCK 150(1.2%), YCK 258(0.6%). The dominant serogroup YCK 117 was distributed 51.9 for Namjeju, 45.8 for Goseong, 41.7 for Iksan. 34.2 for Sueveon, and 11.1% for Milyang soils.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.61-67
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• 1982

Optical properties of sea water were studied in the southern sea of Korea, based on ten oceanographic stations in July, 1980. Submarine daylight intensity was measured at intervals of 5m depth in the upper 70m layer by using the underwater irradiameter (Kahlsico # 268 WA 360). The mean absorption coefficients of the sea water were shown as 0.102 (0.066~0.137), 0.119 (0.069~0.154), 0.091 (0.054~.0123), and 0.095 (0.056~0.129) for clear, red, green, and blue color respectively. The transparency ranged from 13 to 25 meters (mean 17.1 m). The mean water color in this area was 3.9 (3-5) in Forel scales. The relation between absorption coefficient (k) and transparency (D) was k=1.17/D, k=2.01/D, k=1.52/D, and k=1.60/D for clear, red, green, and blue color respectively. The rates of light penetration for clear, red, green, and blue color in four different depths were computed with reference to the surface light intensity respectively. The mean rates of light penetration in proportion to depths were as follows; clear : 57.3%(5m), 20.82%(15m), 5.16%(30m), 0.94%(50m). red : 52.2%(5m), 15.99%(15m), 2.99%(30m), 0.39%(50m). green : 60.9%(5m), 24.51%(15m), 7.11%(30m), 1.56%(50m). blue : 59.4%(5m), 22.92%(15m), 6.09%(30m), 1.29%(50m).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.87-96
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• 2012

The U.S. Geological Survey (USGS) announced that an earthquake of 9.0 magnitude had occurred near the east coast of Japan on March 11, 2011, resulting in a displacement of the crust of about 2.4 meters. The Korean peninsula is located on the Eurasian tectonic plate that stretches out to Japan; therefore, there is a high possibility of being affected by an earthquake. The Korean GPS CORS network operated by the National Geographic Information Institute (NGII) was processed for ten days before and after the earthquake. Both static and kinematic baseline processing were tested for the determination of crustal deformation. The static baseline processing was performed in two scenarios: 1) fixing three IGS stations in China, Mongolia and Russia; 2) fixing SUWN, one of the CORS networks in Korea, in order to effectively verify crustal deformation. All data processing was carried out using Bernese V5.0. The test results show that most of the parts of the Korean peninsula have moved to the east, ranging 1.2 to 5.6 cm, compared to the final solution of the day before the earthquake. The stations, such as DOKD and ULLE that are established on the islands closer to the epicenter, have clearly moved the largest amounts. Furthermore, the station CHJU, located on the southwestern part of Korea, presents relatively small changes. The relative positioning between CORS confirms the fact that there were internal distortions of the Korean peninsula to some extent. In addition, the 30-second interval kinematic processing of CORS data gives an indication of earthquake signals with some delays depending on the distance from the epicenter.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.161-168
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• 1985

The 38 typical profiles representing volcanic ash soils (VAS) in Korea were subjected to multiple regression analysis to determine the relative contribution of organic matter (OM) and clay content to total cation-exchange capacity (CEC). This study, also, was examined the soil characteristics of VAS. VAS in Korea could be classified into 3 Orders, 5 Suborders, 8 Great groups, 15 Subgroups, 23 Families, and 38 Series. Total area of VAS was 139, 162ha and the most of them occured in Jeju Island. Simple correlation coefficients showed significance relations at OM-CEC and clay-CEC in top-soil of VAS. The partial regression coefficients indicated that CEC for each gram of OM as calculated to be 0.46 and 0.40 me per of topsoils for the black volcanic ash soils (BVAS) and the very dark brown volcanic ash soils (VDBVAS), respectively. The clay contributions of topsoils for BVAD and VDBVAS were 0.11 and 0.19 me. The standard partial regression coefficients appeared that OM content of topsoil for BVAS and VDBVAS was 2.97 and 1.23 times as important as clay content in predicting CEC.