• Economic and Environmental Geology
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• v.28 no.4
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• pp.395-404
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• 1995

The geologic structure of the Cheju volcanic island has been investigated by analyzing the gravity and magnetic data. Bouguer gravity map shows apparent circular low anomalies at the central volacanic edifice, and the maximum difference of the anomaly values on the island appears to be 30 mgal. The subsurface structure of the island is modeled by three-dimensional depth inversion of gravity data by assuming the model consists of a stacked grid of rectangular prisms of volcanic rocks bounded below by basement rocks. The gravity modeling reveals that the interface between upper volvanic rocks and underlying basement warps downward under Mt. Halla with the maximum depth of 5 km. Magnetic data involve aeromagnetic and surface magnetic survey data. Both magnetic anomaly maps show characteristic features which resemble the typical pattern of total magnetic anomalies caused by a magnetic body magnetized in the direction of the geomagnetic field in the middle latitude region, though details of two maps are somewhat different. The reduced-to-pole magnetic anomaly maps reveal that main magnetic sources in the island are rift zones and the Halla volcanic edifice. The apparent magnetic boundaries inferred by the method of Cordell and Grauch (1985) are relatively well matched with known geologic boundaries such as that of Pyosunri basalt and Sihungri basalt which form the latest erupted masses. Inversion of aeromagnetic data was conducted with two variables: depth and susceptibility. The inversion results show high susceptibility bodies in rift zones along the long axis of the island, and at the central volcano. Depths to the basement are 1.5~3 km under the major axis, 1~1.5 km under the lava plateau and culminates at about 5 km under Mt. Halla. The prominent anomalies showing N-S trending appear in the eastern part of both gravity and magnetic maps. It is speculated that this trend may be associated with an undefined fault developed across the rift zones.

• Research in Plant Disease
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• v.19 no.2
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• pp.90-94
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• 2013

Potato cv. 'Haryeong' was bred with high solids, resistance to late blight and good culinary quality. It has been registered as new potato variety in 2005. Tuber necrosis symptoms such as severe superficial necrosis, raised surface lesions and ringed necrotic areas were found in tubers of 'Haryeong' during storage of seed potatoes in 2010. Potato virus Y (PVY) was detected from these symptomatic tubers by the analysis of RT-PCR using a primer set specific to coat protein gene of PVY. The nucleotide sequence of RT-PCR product ($PVY^{Hkr}$) was determined and compared to those of other strains, such as $PVY^{Kor}$, $PVY^N$, $PVY^{NTN}$, $PVY^O$, and $PVY^C$ registered in GeneBank. The result showed that $PVY^{Hkr}$ was exactly the same as $PVY^{Kor}$, Korean isolate reported in 2005, except two nucleotides. To verify the PVY was responsible for the tuber necrosis symptoms shown in the tubers of 'Haryeong', a bioassay was done using two viruses (PVY and Potato leafroll virus) and five potato cultivars ('Haryeong', 'Superior', 'Atlantic', 'Dejima', and 'Chubaek'). As expected, the same necrosis symptom appeared in tubers of 'Haryeong' infected with PVY only during the storage period.

• Korean Journal of Social Welfare
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• v.68 no.1
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• pp.23-52
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• 2016

This study aims to reveal the meaning and essence of male immigrant workers' life who underwent industrial accidents through specific experiences. This study is based on the Van Manen(1990)'s lived experience phenomenological method, which actively describes the experiences about the industrial accidents in the perspective of male immigrant worker. The in-depth interviews were carried out with the thirteen male immigrant workers participants who underwent the industrial accidents. Through the interview, 121 meaning units and 38 disclosed themes were constructed. The following is the summarized results as 9 essential themes: < the oppression of the Industrial accident compensation insurance's hospitals to the aliens >, < being treated like the surplus man who lost the labor force >, < the class rank below despite undergoing the industrial accidents >, < survival having resistance sentiments >, < living at the anonymous lands as the Homo sacer >, < the stratified strategies between the immigrant workers >, < the origins as the bodiless shadow >, < struggling to escape the present conditions >, < present circumstances tied by the past experiences without hope >, researcher sought the essential meaning structure about the four Life-world Existentials (Body, The other, Space and Time) of constructing human's live-world. Based on the study results, some suggestions were made to restore the male immigrant workers' damaged quality of their lives who experienced industrial accidents and to contribute the social integration in view of the social welfare.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.197-208
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• 2003

This paper is to determine the possibility of re-using waste concrete from Incheon city area. The strength test was conducted with five aggregate compounds which was replaced a natural aggregate with recycled aggregate. After checking the physical characteristics of recycled aggregate compounds, the mix design of recycled concrete was conducted. For the relatively comparison between natural and recycled compounds, while the unit aggregate weight was changed, other conditions were fixed. The freezing and thawing test which included fly-ash and super-plastezer were performed to check the durability and workability when recycling waste concrete. In the physical characteristics of recycled aggregate, it was found that the specific gravity of recycled coarse aggregate and recycled fine aggregate satisfied the first grade of recycle specification(KS), and all compounds of recycled aggregate also satisfied the second grade of absorption specification, Especially up to the 50% substitution of recycled aggregate is equal to or a bit lower than that of convention aggregate. In comparison with conventional concrete, the recycled concrete is lower than maximum by 7% in compressive strength decreasing rate after freezing-thawing test. From now, although most of recycled concrete was used to the building lot, subgrade, asphalt admixture, through the result. It was proved that possibility of re-using recycled aggregate as the substructure of bridge, retaining wall, tunnel lining and concrete structure which is not attacked the drying shrinkage severely.

• Journal of Environmental Policy
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• v.13 no.4
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• pp.79-105
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• 2014

Natech risk is a type of complex disasters that natural hazards trigger technological disaster or industrial accidents. Research on Natech risk has been started from the mid-1990s in European countries and the Unites States, and drawn much more attention after the Fukushima nuclear accident caused by the 2011 East Japan earthquake. While early studies on Natech risk have focused on the causal natural hazards and possibility to occur, and the resulting spill of hazardous materials from the perspective of science and engineering, the recent research interests lie on effective Natech risk management. Especially, emphasizing the difference of Natech risk management from traditional disaster management, issues of uncertainty management, integration between natural disaster and technological disaster, and responsibility, has been drawn attention. In Korea, Natech risk has not been introduced as a research topic. Although some regulatory improvements have been made in nuclear safety and chemical Substance management after the Fukushima disaster, the potential impact of natural hazards in these areas has not been considered yet. It is necessary to raise the issues of Natech risk management in research and policy areas through active discussion and interdisciplinary approaches.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.197-206
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• 2004

The ground anchor support system may not be occasionally used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then could play important roles to reduce deformations mainly in the upper part of the nailed-soil excavation system as well as to improve local stability. In this study, a newly modified soil nailing technology named as the PSN (Pretension Soil Nailing), is developed to reduce both facing displacements and ground surface settlements in top-down excavation process as well as to increase the global stability. Up to now, the analytical procedure and design technique are proposed to evaluate maximum pretension force and stability of the PSN system. Also, proposed are techniques to determine the required thickness of a shotcrete facing and to estimate probability of a failure against the punching shear, Based on the proposed procedure and technique, effects of the radius of a influence circle and dilatancy angle on the thickness of a shotcrete facing, bonded length and safety factors are analyzed. In addition, effects of the reduction of deformations expected by pretension of the soil nails are examined in detail throughout an illustrative example and the $FLAC^{2D}$ program analysis. And a numerical approach is proposed PSN system using the shear strength reduction technique with the $FLAC^{2D}$ program.

• Journal of the Korean Geographical Society
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• v.40 no.6 s.111
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• pp.716-729
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• 2005

In the Yeongpyeong River, one of the branches of Hantan River, there 4 fluvial terraces are identified. During the Quaternary, lava flow from Hantan River had gone 4.5km into upstream Part of the Yeongpyeong River and damed its entrance, and resultantly its lower basin had become a lava-damed paleolake. This study deals with fluvial terrace surface classification, stratigraphic analysis, deposits analysis, and OSL age dating in from Gungpyeongri to Seongdongri in lower reach of Yeongpyeong River, in order to identify Seomorphological Process of the terrace landforms relating to duration of lava-damed paleolake. Terrace surface T4, named Baekeuiri Formation, has been located under Jeongok lava layer to indicate pre-lava river bed. Terrace surfaces T3 and T2 are supposed to be formed during paleolake time, based on $3{\~}4m$ thick sand deposits including pebble and cobble layers, and clay and silt layers intersected with sand ones in nearly horizontal bedding. Terrace T1 is estimated to be formed as post-lake fluvial terrace after dissection of lava dam, based on the more fresh phase of deposits and very low height from present riverbed. The results of the OSL age dating for the T3 deposit layers indicate approximately $33{\~}40ka$, and still lake phase at that time.

• Journal of Mushroom
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• v.18 no.3
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• pp.201-207
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• 2020

Mushrooms growing in the Wolchulsan National Park were surveyed from April to October 2018. As a result of this survey, 2 divisions, 9 classes, 24 orders, 71 families, 177 genera, and 407 species were found. Among them, 3 classes, 16 orders, 55 families, 150 genera, and 370 species belonged to Basidiomycota, while 6 classes, 8 orders, 16 families, 27 genera, and 37 species belonged to Ascomycota. The species richness was the highest in September at the altitudes between ~100 and 200 m. Among the investigated sites, the most diverse species occurred in the Gyeongpodae area. In this survey we found, Macrolepiota procera, Suillus bovinus, and Amanita pantherina, all of which have been known as climate-sensitive biological indicator species (CBIS). Based on the DNA sequence analyses, Craterellus parvogriseus was confirmed as a new record for Korea.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.649-660
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• 2015

Data obtained from the Calpuff inverse modeling estimate the emission amount of pollutants, and enable to establish the aim for reduction through the comparison of various cases. This study pursued to accumulate the fundamental data by the Calpuff inverse modeling for five areas in the vicinity of Donghae harbor, which focused on reduction of atmospheric fine dust. As a result of evaluation of the allowed emission amount for local sites, site-D required the most reduction, $4.95{\mu}g/m^2{\cdot}S$, based on the atmospheric guideline, $50{\mu}g/m^3$. The theoretical mitigation could decrease the average concentration of PM10 to $42.6{\mu}g/m^3$ for the study field (Donghae waste water treatment plant). Modeling only for site-A emission showed the potential concentration around the residential area of Donghae harbor, $40{\sim}50{\mu}g/m^3$. However, it will rise over $50{\mu}g/m^3$ with the addition of background level. Therefore no more emission would be allowed. Site-B including commercial area and unpaved field required the reduction of $0.11{\mu}g/m^2{\cdot}S$ due to vehicles and fugitive dust. Site-C and E did not emit additional pollutants.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.313-313
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• 2011

오염물질은 배출원의 형태에 따라 점오염물질과 비점오염물질로 구분하고 있고 점오염물질은 생활하수, 산업폐수, 축산폐수, 환경기초시설 방류수 등으로 발생원이 명확하고 수집하여 처리 및 관리가 용이하나 비점오염물질은 배출위치가 명확하지 않으며, 강우 시 일시적으로 대량 배출되는 특징을 가진 농경지, 도로, 대지, 임야 등에서 배출되는 오염물질을 말한다. 우리나라에서 비점오염은 전체 수질오염의 42~67%(2003년)를 차지하는 것으로 나타났고, 2015년에는 전체 수질오염의 65~75%에 이를 것으로 예상되고 있다. 이 중 농업 비점오염원은 총 수질 오염량의 30%이상을 차지할 것으로 추정하고 있으나 이를 저감하기 위한 최적관리방법의 효과검증에 관한 연구는 아직 미미한 상태이다. 이에 본 연구에서는 농경지 중 밭에서 발생하는 비점오염을 저감하기 위한 기법으로 다양한 규모와 형태의 Silt Fence/식생밭두렁/침사구를 설치하여 밭 비점오염에 대한 저감효과를 평가하고 제어대책을 개발하여 최적관리기법을 제시하고 이에 대한 매뉴얼을 개발하기 위한 기초연구를 실시하려 한다. Silt Fence는 주로 건설공사현장에서 홍수유출 발생 시 인접한 하천 및 호소 등으로 유사 및 오염물질이 유입되는 것을 방지하기 위해 임시적으로 설치하는 시설로 합성 직물 필터를 나무나 금속 막대로 연결하여 등고선 방향으로 설치하는 것으로 대상 지역의 토양이 교란되기 전에 그 지역 아래쪽에 설치한다. 식생밭두렁은 밭의 이랑의 길이가 길어질수록 강우 시 빗물이 하단에 이를 때 늘어난 유량과 빠른 유속으로 토양침식이 가중되는데, 이때 30~35m간격으로 식생밭두렁을 설치하게 되면 상부와 하부의 침식정도가 유사한 경향을 보여 식생밭두렁을 설치하지 않은 지역에 비해 토양의 침식정도가 작게 나타나게 된다. 이러한 Silt Fence/식생밭두렁/침사구의 밭 비점오염의 저감효과 평가 및 제어대책 개발을 위한 기초 실험을 수행하기 위해 경상남도 사천시 용현면 선진리 일대에 시험포장을 조성 하였으며, 시험포장내에 6개의 Plot을 만들어 하단부에 포장에서의 유출수의 유량을 측정하기 위해 플룸을 설치하였고 실내실험을 통해 플룸의 수위-유량관계 곡선을 작성하였다. 포장의 토양특성을 판별하기 위해 Plot별로 토양시료를 채취하여 특성을 분석 한 결과 6개 Plot모두 모래함량이 많은 점토질 사질토로 분류되었다. 향후 강우 시 시험포장에서 발생하는 유출수의 수질을 분석하고 Silt Fence/식생밭두렁/침사구의 오염물질 저감효과를 분석하여 제어대책을 개발하게 되면 농업수자원확보를 위한 관리방안 선정을 위한 정책수립에 활용될 수 있으며 비점오염 배출을 최소화시켜 수질의 개선에 기여할 뿐만 아니라 우리나라 농업에 적합한 최적영농관리기술을 개발 할 수 있을 것으로 사료된다.