• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.1
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• pp.1-12
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• 2004

Sedimentary facies and high-resolution echo facies were analyzed to elucidate sedimentation pattern of the late Quaternary glacial-marine deposits in the northern continental margin of the South Shetland Islands. Six sedimentary facies are classified, based on grain texture and sedimentary structures in gravity cores. The high-resolution (3.5 ㎑) echo characters are classified into 6 echo facies on the basis of clarity, continuity, and shape of bottom and subbottom echoes together with seafloor topography. Distribution of the echo and sedimentary facies suggest that there was a significant change in sedimentation pattern between the Last Glacial Maximum (LGM) and subsequent glacier-retreating period. When the grounded glaciers extended to the present shelfbreak during LGM, coarse-grained subglacial tills were widespread in the shelf area, and deep troughs in the shelf were carved beneath the fast-flowing ice steam. As the glacial margin retreated landward after LGM, dense meltwater plumes released from the retreating ice-front were funneled along the glacier-carved troughs, and accumulated channel- or cannyon-fill deposits in the shelf and the upper to mid slope. At that time, slope sediments seem to have been reworked by slope failures and unsteady contour currents, and further transported by fine-grained turbidity currents along the South Shetland Trench. After the glacial retreat, sediments in the shelf and slope areas have been mainly introduced by persistent (hemi) pelagic settling, and fine-grained turbidity currents frequently occur along the axis of the South Shetland Trench.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.2
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• pp.103-113
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• 2001

This study presents Quaternary sedimentation pattern around Dok-Island volcanoes (Dok Island and Dok Seamount), based on analysis of high-resolution (chirp) echo characters. Echo facies If, showing sharp, continuous bottom echo without subbottom reflectors, is recorded mainly from the flat tops of the volcanoes. This facies indicates sands and gravels (re) deposited by shallow marine processes. Echo facies IIA in the basin floor and basal slopes of the volcanoes and Oki Bank is characterized by semi-prolonged bottom and several parallel subbottom echoes. This facies reflects hemipelagic settling with intermittent influences of turbidity currents in the slope areas. Echo facies IIC is recorded from acoustically-transparent debrite masses on the basal slopes of the volcanoes and Oki Bank. Echo facies IIIA is characterized by irregular hyperbolic echoes in the slope areas of the volcanoes. It suggests hard rock basement or irregular volcanic edifices. Echo facies IIIC shows regularly-overlapping hyperbolic bottom echoes. It is interpreted to represent rock-fall deposits (talus) accumulated in the mid-slope area. Echo characters and topography suggest that the tops of Dok-Island volcanoes were flattened and lowered by shallow-marine erosional processes. The eroded sediments were transported to and deposited in the base of slope and basin plain mainly by debris flows and turbidity currents along submarine canyons and valleys.

• Korean Journal of Agricultural Science
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• v.6 no.2
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• pp.125-133
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• 1979

The characteristics of landslides occurred in August 5, 1979 in pyeongchangkun were surveyed and indentified as follows. 1. Deep limestone regions. Distinct differences in soil texture between A1 and B horizon could be observed on soil profile, which is attributed to the clay illuviation. The clay illuvial horizon is supposed to be an important cause of large scale mudflows on middle slopes by the lubricant action of ground water flowing between top soil and subsoil. 2. Shallow limestone regions. Very shallow top soils (less than 50cm) laid on tilted bedrock stratification provide a proper condition of mass soil movement if the top soil is saturated and ground water flows between top soil and bedrock when concentrated heavy rainfalls shower. 3. Granite regions. Weathering granitic bedrock produces very coarse textured top soils which are very cohesionless and have many pores. Therefore, the soil has high infiltration ratio and is easy to be saturated by water and to be detached from the bedrock. The landslides abrase very severely both sides of gully with high potential energy when they flow down. The following methods for landslide prevention can be recommended. 1. The original parts of landslides on top of the gully must be treated by intensive planting of deep rooting species and check dams. 2. Clear-cutting and crop planting on steep slope (more than 25 degrees) should be controlled and prohibited. 3. Establishment of landslide prevention forest should be practised on proper site.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.107-116
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• 2018

In this study, the distribution of sedimentary environment and benthic macro-fauna in habitats and non-habitats of Zostera marina were investigated. The purpose of this study was to obtain basic data about the sedimentary environment and benthic macro-fauna in the habitats and non-habitats of Z. marina. Sand was dominant within habitat environments, whereas the non-habitats were predominantly composed of silt. As a result, the habitats of Z. marina have a different grain size and organic matter content compared to the non-habitats. These differences in the sedimentary environment were expected to influence the species composition of benthic animals. Benthic communities in the habitats of Z. marina showed a higher density and a greater number of species than in the non-habitats. As a result of an ecological index evaluation, the species diversity index (H') was $3.44{\pm}0.10$ for the habitat; the non-habitat was analyzed as $2.34{\pm}0.35$. It was also found that the stability of community in the habitats was higher than that in the non-habitats. The cluster analysis also clearly showed that habitats and non-habitats of Z. marina have distinct characteristics.

• Environmental and Resource Economics Review
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• v.18 no.4
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• pp.653-693
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• 2009

Using the Korean environmental input output analysis, this paper provides the emission intensities of the chemicals, especially, the toxic and carcinogenic substances, by linking the structure of demand, and the policy mix to abate these substances emissions. Acording to the results, Industries with the highest total emission intensities(TEI) of toxic substances are ranked : Printing and reproduction of recorded media(21), Other transportation equipment(26), Pulp and paper(11), Leather and fur products(9), Fiber yarn and fabrics(7). And the highest TEI of carcinogenic substances are Wood and wooden products(10), Motor vehicles and parts(25), Plastic and rubber products(15), Audio, video and communications equipment(23), etc.. The economic factors of changing these emissions are emission intensities and final demands. The effective combinations of policy instruments to abate these emissions are varied by the industries and substances. For example, Government need to execute the effective TEI management in the Fiber yarn and fabrics(7) sector, and, in furniture(27) sector, the reduction of final demand is more effective.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.97-105
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• 2021

Tegillarca granosa, is one of the most important fishery resources throughout Asia. However, due to industrialization factories, marine environmental pollution, and global warming, the marine fishery production has drop sharply. In order to understand the genetic factors of the blood clam, which is a major fishery resource on the southern coast of Korea, the whole genome of blood clam was studied. The assembled genome of T. granosa was 915.4 Mb, and 19 chromosomes were identified. 25,134 genes were identified, and 22,745 genes were functionally annotated. As a result of performing gene gain and loss analysis between the blood clam genome and eight other types of shellfish, it was confirmed that 725 gene groups were expanded, and 479 gene groups were contracted. The homeobox gene cluster of blood clam showed a well-preserved genetic structure within lophotrochozoan ancestor. T. granosa genome showed high similarity between three hemoglobin genes with Scarpharca broughtonii. The blood clam genome will provide information for the genetic and physiological characteristics of blood clam adaptation, evolution, and the development of aquaculture industry.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.495-495
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• 2022

충적하천에 댐이 건설되면 하류 하천의 식생환경에 변화를 주게 된다. 이입, 활착 및 성장과정을 거치는 제외지 식생은 하천의 유량이 증가하면 소류력과 세굴로 인해 쓸려 내려가기 때문에, 일반적으로 홍수기를 거치면 식생 활착 및 성장 이전의 사주 모습으로 복귀하게 된다. 그러나 댐의 홍수조절 기능은 홍수기에도 하류 하천에 식생을 정착시킬 만큼 큰 소류력을 발생시키지 않아 결국 식생의 성장에 기여하게 된다. 또한 댐은 상류로부터 공급되었던 세립토를 차단시켜 하류 하천의 하상 표면을 조립화 시키게 되는데, 이는 하상의 고정력을 증대시켜 식생의 안정적인 성장을 돕게 된다. 하천에 식생이 자리잡게 되면 홍수 시 흐름에 대한 저항력의 증가로 수위가 높아질 수 있고 제방에 자리 잡은 식생의 이탈은 제방의 붕괴 위험을 증가시킬 수 있고, 식생 사주의 발달이 지속되면 이동사주에서 정지사주로 변화되어 기존의 충적하천 자체가 사라지게 될 수도 있고, 하류 하천의 수리 및 유사 거동 특성도 변화시켜, 기존과 다른 하천 경관 및 수생태계 출현할 수 있다. 국내에서는 2000년대부터 이러한 하천 제외지 사주의 식생 활착이 가속화되어 왔으며, 특히 내성천, 황강 등 댐이 건설된 낙동강 지류 하천에서 이런 현상이 두드러지게 나타났다. 이에 따라 관련된 많은 조사·연구들이 수행되었으며, 변화 원인으로 홍수조절, 유사공급 변화 및 기후변화가 제시되었다. 그러나 댐이 건설되지 않은 하천(비조절 하천)에 대한 조사와 같은 비교군 지역의 정량적 분석은 상대적으로 부족하여, 정확한 제외지 식생 증가에 대한 원인을 규명하지 못하였다고 판단된다. 이에 비조절 하천이라 판단되는 감천을 대상으로 식생의 변화 양상을 분석하고, 유사 및 기후변화 등과의 관계를 본 연구에서 제시하였다. 감천은 상류에 김천부항댐이 건설되었으나, 댐의 영향범위가 전체 유역면적의 약 6%로 비조절 하천에 가깝고 사주가 발달된 충적하천이므로, 하천 본류에 댐이 건설된 다른 지역과의 비교군으로 적합하다고 판단하였다. 대상 지점은 상, 중, 하류의 사주가 발달된 지역으로 선정하였고, 본 연구에서 개발된 이미지 처리기법을 적용하여 사주 면적을 계산하였다. 분석결과 식생역으로 전환된 모래 사주의 면적은 봄~초여름 강우량과 밀접한 관계가 있는 것으로 파악되었다. 특히 초여름까지 가뭄이 지속될 때, 식생역은 증가하였다. 그러나 식생 활착 이전에 큰 유량 발생 시 식생이 쓸려 내려가고 유사가 그 자리를 대체하여 다시 사주가 발달하는 과정을 보여 주어, 감천의 사주 식생역의 증가 추세는 없는 것으로 파악되었다. 향후 댐이 본류에 건설된 조절 하천과의 비교를 통해 사주의 식생역 증가에 대한 댐 건설의 영향을 파악할 것이다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.181-188
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• 2009

The macro tidal flat of the Gochanggun Myongsasipri, located on the southwestern coast of Korea, is studied in terms of seasonal variations of surface sediment and sedimentary environment. Surface sediments of 45 sites in the winter (February) and the summer (August) are sampled across three survey lines (15 sites in each survey line), respectively. The tidal flat of open-coast Myongsasipri is mainly composed of fine to medium sand, the distribution of which shows a coast-parallel trend. Grain-size distribution has a bi-modal trend, and grain size in the winter is coarser than that in the summer. During the winter, the upper tidal flat is dominated by medium sand, while the lower tidal flat is dominated by find sand. Such a feature is attributed to wave-dominated sedimentation in the winter. The finer grains of the summer rather than that of the winter and relationship between texture parameters suggest that tidal energy plays an important role in tidal-flat sedimentation during the summer. This study represents an environmental change from wave-dominated conditions in the winter to tide-dominated conditions in the summer as a result of the seasonal variation in the intensity of onshore-directed winds and waves in the Myongsasipri tidal flat.

• Journal of Korean Society of Steel Construction
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• v.25 no.2
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• pp.115-130
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• 2013

In this study, lateral-torsional buckling (LTB) strength of high-strength H-beams built up from 800MPa tensile-strength steel was experimentally and analytically evaluated according to current lateral stability provisions (KBC 2009, AISC-LRFD 2010). The motivation was to evaluate whether or not current LTB provisions, which were originally developed for ordinary steel with different stress-strain characteristics, are still applicable to high-strength steel. Two sets of compact-section specimens with relatively low (Set A) or high (Set B) warping stiffness were prepared and tested under uniform moment loading. Laterally unbraced lengths of the test specimens were controlled such that inelastic LTB could be induced. All specimens exhibited LTB strength exceeding the minimum limit required by current provisions by a sufficient margin. Moreover, some specimen in Set A reached a rotation capacity required for plastic design, although its laterally unbraced length belonged to the inelastic LTB range. All the test results indicated that extrapolation of current provisions to high-strength steel is conservative. In order to further analyze the test results, the relationship between inelastic moment and laterally unbraced length was also derived in explicit form for both ordinary- and high-strength steel based on the effective tangent modulus of inelastic section. The analytical relationship derived again showed that extrapolation of current laterally unbraced length limit leads to a conservative design in the case of high-strength steel and that the laterally unbraced length to control the inelastic LTB behavior of high-strength steel beam should be specified by including its unique post-yield strain-hardening characteristics.

• Korean Journal of Heritage: History & Science
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• v.38
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• pp.387-419
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• 2005

Material characteristics and provenance interpretation of the raw materials for the stone moulds of bronze artifacts excavated in Galdong Prehistoric site were studied. The stone moulds are made of igneous hornblendite with coarse-grained holocrystalline textures. The surface color shows greenish grey to dark green with greasy luster. The value of magnetic susceptibility of the moulds ranges from 19.2 to 71.0 (mean ; $39.2{\times}10^{-3}$ SI unit).High value of magnetic susceptibility indicates high contents of magnetite as a ferromagnetic mineral and the wide range of the values are due to heterogeneous distribution of magnetite. These are characteristics of basic igneous rocks. The rock-forming minerals of the moulds mainly consist of amphibole, plagioclase and biotite. Pyroxene, chlorite and opaque minerals are also rarely present. A large quantity of carbon was detected on the dark black crust near the surface of the moulds by quantitative analysis. Geological field survey was carried out to identify a source of the raw materials of the stone moulds around Galdong site. Hornblendite or gabbroic rocks being similar to the moulds forming rock occur at Daeseongri, Sikcheonri and Gyodongri in Jangsoo, and Illdaeri in Namwon about 50 kilometers away from the site in a straight line. They have similarity with the moulds forming rock in magnetic susceptibility ranging from 16.1 to 72.4 (mean ; $39.9{\times}10^{-3}$ SI unit). Among those hornblendite or gabbroic rocks, one in Jangsoo area is the most similar to the moulds forming rock on the basis of petrological and mineralogical characteristics. Comparing normalized patterns of major, minor, rare earth and immobile elements contents of the moulds to them of hornblendite in Jangsoo area, geochemical evolution trend and behavior characteristics show affinities between them. It suggests that the moulds forming rock and hornblendite in Jangsoo area have been originated from cogenetic magma. This hornblendite is easy to engrave an inscription or detail graphics on the surface because of its softness, and has good thermal conductivity. Hornblendite in Sikcheonri, Jangsoo is particularly produced and used for stone wares until the present day. Therefore, it is probable that the stone materials of the moulds has been imported from Daeseongri, Sikcheonri and Gyodongri in Jangsoo area. However, it cannot be completely excluded the possibility that the material of the moulds was supplied from Illdaeri in Namwon area appearing the same type of hornblendite on a small outcrops. It is necessary to carry out further archaeological studies to identify several possibilities of migration process of raw materials.