• 한국안전학회지
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• 제31권5호
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• pp.22-27
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• 2016

The Electrostatic Charge Prevention Technology is a core factor that highly influences the yield of Ultra High Resolution Flat Panel Display and high-integrated semiconductor manufacturing processes. The corona or x-ray ionizations are commonly used in order to eliminate static charges during manufacturing processes. To develop such a revolutionary x-ray ionizer that is free of x-ray radiation and has function to control the volume of ion formation simultaneously is a goal of this research and it absolutely overcomes the current risks of x-ray ionization. Under the International Commission on Radiological Protection, it must have a leakage radiation level that should be lower than a recommended level that is $1{\mu}Sv/hour$. In this research, the new generation of x-ray ionizer can easily control both the volume of ion formation and the leakage radiation level at the same time. In the research, the test constraints were set and the descriptions are as below; First, In order not to leak x-ray radiation while testing, the shielding box was fully installed around the test equipment area. Second, Implement the metallic Ring Electrode along a tube window and applied zero to ${\pm}8kV$ with respect to manage the positive and negative ions formation. Lastly, the ion duty ratio was able to be controlled in different test set-ups along with a free x-ray leakage through the metallic Ring Electrode. In the result of experiment, the maximum x-ray radiation leakage was $0.2{\mu}Sv/h$. These outcome is lower than the ICRP 103 recommended value, which is $1{\mu}Sv/h$. When applying voltage to the metallic ring electrode, the positive decay time was 2.18s at the distance of 300 mm and its slope was 0.272. In addition, the negative decay time was 2.1s at the distance of 300 mm and its slope was 0.262. At the distance of 200 mm, the positive decay time was 2.29s and its slope was 0.286. The negative decay time was 2.35s and its slope was 0.293. At the distance of 100 mm, the positive decay time was 2.71s and its slope was 0.338. The negative decay time was 3.07s and its slope was 0.383. According to these research, the observation was shown that these new concept of ionizer is able to minimize the leakage radiation level and to control the positive and negative ion duty ratio while ionization.

• 한국환경복원기술학회지
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• 제19권6호
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• pp.123-132
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• 2016

The study was to introduce the revegetation measures for the improvement of the landscape in October, 2012 on the slope; two and four years after the introduction, the slope was examined to see the status of the revegetation. The result is as follows. The result from examining the soil on the slope, the soil was Loamy sand; which infers that the soil is in a poor condition for improving the scenery. Examining the characteristics of the vegetation-base materials, the soil acidity was pH 6.4 to 6.7; and the soil hardness was 21 to 24mm (hardness quotient of soil), this can be considered a favourable condition, which has no effect on the growth and development of plants. When it comes to the discovery of the species in the area, Lotus corniculatus var., Silene armeria L., Papaver rhoeas, Trifolium pratense L. developed and grew in spring after two years. And in the summer, Lotus corniculatus var., Dianthus chinensis L., Cosmos bipinnatus, Coreopsis drummondii L., Trifolium pratense were founded. And there were Lotus corniculatus var., Dianthus chinensis L., Aster yomena, Coreopsis tinctoria, Trifolium pratense L. in the autumn. According to the examination conducting after four years, Lotus corniculatus var., Dianthus chinensis L., Silene armeria, Cosmos bipinnatus, Coreopsis drummondii L., Papaver rhoeas, Trifolium pratense L. were founded in the spring, and Lotus corniculatus var., Dianthus chinensis L., Cosmos bipinnatus, Coreopsis drummondii L., Trifolium pratense grew in the summer. Lotus corniculatus var., Dianthus chinensis L., Astragalus sinicus, Aster yomena, Coreopsis tinctoria, Trifolium pratense L. were discovered in the autumn. Among the exotic species founded in the area, were Festuca arundinacea, Lolium perenne, Festuca rubra. When it comes to the protection of vegetation and dominance, Lotus corniculatus var., Metaplexis japonica, Coreopsis drummondii L. are the dominant species among the spring plants; and Lotus corniculatus var., Trifolium repens L., Erigeron annuus (L.) Pers. were the dominant plants in the summer. In the autumn, Lotus corniculatus var., Coreopsis drummondii L., Poa pratensis appear to be the dominant plants. The colonies of Pinus densiflora and Castanea crenata var. were formed around the South Sejong IC. Part of the area is occupied by the colony of Alnus hirsuta Turcz. ex Rupr. In terms of shrub, there were Indigofera pseudo-tinctoria, Robinia pseudoacacia, and Rosa polyantha var. genuina NAKA. As ground cover plants, Sasa borealis, Rubus crataegifolius Bunge were founded.

• 한국조경학회지
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• 제25권4호
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• pp.39-50
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• 1998

The object of this study was to examine and analyze the environmental deterioration of three major trails and around peak area of Moaksan Provincial park in 1996. Trails are mostly made up at ridgeline and the slope of them is gentle. Mean trail width is 3.6m, and total length of branch trails is 982m in survey area. The environmental deterioration is derived from trail extension. Maximum eroded depth and cross-section area loss are 89cm and 14,050cm2 respectively, and gully erosion type appears at many sites. The environmental deterioration of trails is very heavy at the sections from Khui to Moaksan peak and from Moakchong to ascent part around the peak. The entire width, branch trail, maximum depth, cross-sectional area loss and surface roughness, as the indexes of trail conditions, are significantly greater at the more heavily used trails. Amount of erosion is influenced by eroded depth, longitudinal slope, runoff influence and entire width in descending order as well as the amount of use. Safety and protection facilities on the trail such as stone and soil stairs, rope handrail, stone channel and soil ditch work are built, but they are very deficient. Bared lands about 4,900m2 and fill slopes are caused and formed by recreation activities and constructions around peak area. It is required to carry the recess system and to conserve and rehabilitate the destroyed trail sites and bare fill slopes as soon as possible, before the environmental deterioration becomes critical because of increased used amount in consequence of construction of recreation parks.

• 한국항해항만학회지
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• 제28권7호
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• pp.619-627
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• 2004

Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Ulsan Harbor and Ulsan New Port, etc. due to construction of New Port in Ulsan Bay. We also considered the increase of water depth at the entrance channel by dredging work up to 15 meters depth in order to see the dredging effect. Among several model analyses, the nonlinear and breaking wave conditions are showed the most applicable results. This type of trial might be a milestone for port development in macro scale, where the induced impact analysis in the existing port due to the development could be easily neglected.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.217-225
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• 2004

Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Ulsan Harbor and Ulsan New Port, etc. due to construction of New Port in Ulsan Bay. This type of trial might be a milestone for port development in macro scale, where the induced impact analysis in the existing port due to the development could be easily neglected.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제4권4호
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• pp.159-176
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• 2023

The conservation of the raccoon dog (Nyctereutes procyonoides) in South Korea requires the protection and preservation of natural habitats while additionally ensuring coexistence with human activities. Applying habitat map modeling techniques provides information regarding the distributional patterns of raccoon dogs and assists in the development of future conservation strategies. The purpose of this study is to generate potential habitat distribution maps for the raccoon dog in South Korea using geospatial technology-based models. These models include the frequency ratio (FR) as a bivariate statistical approach, the group method of data handling (GMDH) as a machine learning algorithm, and convolutional neural network (CNN) and long short-term memory (LSTM) as deep learning algorithms. Moreover, the imperialist competitive algorithm (ICA) is used to fine-tune the hyperparameters of the machine learning and deep learning models. Moreover, there are 14 habitat characteristics used for developing the models: elevation, slope, valley depth, topographic wetness index, terrain roughness index, slope height, surface area, slope length and steepness factor (LS factor), normalized difference vegetation index, normalized difference water index, distance to drainage, distance to roads, drainage density, and morphometric features. The accuracy of prediction is evaluated using the area under the receiver operating characteristic curve. The results indicate comparable performances of all models. However, the CNN demonstrates superior capacity for prediction, achieving accuracies of 76.3% and 75.7% for the training and validation processes, respectively. The maps of potential habitat distribution are generated for five different levels of potentiality: very low, low, moderate, high, and very high.

• 한국산림과학회지
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• 제95권1호
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• pp.45-49
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• 2006

본 연구는 임도사면 녹화에 주로 사용되는 목 초본 18종에 대한 인발강도특성을 정량적으로 구명하여 환경친화적인 녹색임도의 건설을 위한 적정 녹화식물의 선정시 기초자료로 제공하고자 실시하였다. 17개월동안 성장한 종별 뿌리의 신장한계는 족제비싸리가 34.0 cm로 가장 깊은 것으로 나타났고, 페레니얼라이그라스가 17.7 cm로 가장 얕은 것으로 나타났다. 또한 종별 뿌리의 인발강도는 평균적으로 도입초본 $0.054t/m^2$/본, 재래초본 $0.085t/m^2$/본, 재래목본 $0.649t/m^2$/본으로 나타났으며, 도입초본과 재래초본 간에는 커다란 차이가 없었으나, 초본과 목본 간에는 목본이 약 9배 가량 큰 것으로 나타났다. 또한 녹화식물의 개체수별 평균 뿌리밀도는 도입초본 1.398 ml/본, 재래초본 1.471 ml/본, 재래목본 5.377 ml/본의 순으로 나타났다. 따라서 뿌리에 의한 토양의 고정효과와 토양내 공간이용을 극대화하기 위하여는 침식방지용 초본류와 표층붕괴용 목본류를 혼파하는 것이 바람직할 것이다.

• The Plant Pathology Journal
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• 제35권6호
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• pp.654-661
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• 2019

The soybean cyst nematode, Heterodera glycines, is a major plant-parasitic nematode that has caused important economic losses to Korea's soybean production. Four species of cyst nematodes, H. schachtii, H. glycines, H. trifolii, and H. sojae, all belong to schachtii group are coexist in field soil in Korea. The rapid identification of the nematode is crucial for preventing crop damage and in decision making for controlling this nematode. This study aimed to develop a species-specific primer set for quantitative PCR (qPCR) assay of H. glycines. The specific primer set (HGF1 and HGR1) for H. glycines was designed based on the cytochrome c oxidase subunit I (COI) sequence of mitochondrial DNA. After optimization, it is possible to identify the H. glycines using a qPCR assay with DNA extracted from a single cyst and single second-stage juvenile (J2). The specificity was confirmed by the absence of SYBR fluorescent signals of three other Heterodera species. A serial dilution of DNA extracted from a single cyst was obtained for the sensitivity test. The result showed that the standard curve of the test had a highly significant linearity between DNA concentration and Ct value (R² = 0.996, slope = -3.49) and that the detection limit concentration of DNA of the primer set was 10 pg of DNA per reaction. Our findings suggested that H. glycines could be distinguished from H. sojae and other Heterodera species when a qPCR assay is used with a specific primer set.

• 한국지형학회지
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• 제19권4호
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• pp.59-71
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• 2012

이 연구는 다중시기 원격탐사 영상과 GPS 측량자료 및 입도분석 자료를 이용하여 부산 송정해수욕장의 장기간 해안지형 변화와 원인을 규명하였다. 연구결과, 다중시기 원격탐사 영상 분석에서는 2000년대 초까지 해빈이 전체적으로 안정 상태였으나, 2000년 이후 해안을 따라 호안도로가 건설되면서 전반적으로 침식이 진행되었다. DEM 변화 분석에서는 해빈을 따라 호안도로가 건설된 이후 전체적으로 해빈의 고도가 낮아지고 범의 경사가 급해지는 것으로 보아 침식환경이 우세한 것으로 나타났다. 하지만 세부적으로는 북쪽 해빈지역에서 침식보다는 오히려 퇴적환경이 약간 우세하여 범의 경사가 다소 완만해진 것으로 나타났다. 현장시료의 입도분석에서는 해빈의 남동부 지역(E측선)이 가장 조립화 경향을 보였는데, 이러한 결과는 이 지역이 비교적 외해로부터 유입되는 강한 파랑에너지에 직접적으로 노출되었기 때문이다. 결과적으로 최근 연구지역 내 해빈 침식의 주요 원인은 해안을 따라 건설된 호안도로에 의해 사구로부터의 모래 공급원 차단과 남동쪽 해안에서의 파랑에너지 강화에 따른 세굴 현상 등에 기인한다. 따라서 향후 지형변화나 인위적인 변화가 없을 경우 지속적으로 침식이 될 가능성이 높아 이에 대한 대책수립이 필요하다.

• 한국지반환경공학회 논문집
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• 제12권9호
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• pp.13-20
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• 2011

산지가 많은 우리나라는 도로 및 철도건설을 위해 사면을 형성하는 구간이 많고, 사계절의 뚜렷한 차이로 인해 해빙기에 암블록의 이완현상 발생과 연평균 강우량의 2/3 정도가 여름철에 집중 발생되는 기후특성이 있으며, 최근 기상이변에 따른 집중호우 등으로 낙석 및 산사태와 같은 도로절개면 붕괴사고가 잦은 편이며, 해마다 장마철이 되면 이와 관련된 사고소식을 매스컴을 통해 쉽게 접할 수 있다. 낙석 발생 시 인명과 재산 피해를 최소화하기 위하여 절개지에 대한 보강공법의 개발 및 현장 적용성에 대한 연구 등이 활발히 이루어지고 있지 않는 실정으로 이에 대한 연구의 필요성이 부각되고 있다. 특히 낙석방지망의 부분적 취약점(일체화가 되지 못함)으로 인해 낙석방지망이 충분한 지지능력을 발휘하지 못하는 문제가 발생됨에 따라 국내에서도 보다 높은 낙석에너지를 지지할 수 있는 낙석방지망에 대한 연구가 필요할 것으로 판단된다. 이에 본 연구에서는 낙석방지망의 대체재료로서 팽창메탈의 적용성을 실험적으로 검증하고, 그 특성에 관해 연구해 보고자 하였다. 시험결과 팽창메탈은 우수한 강도와 일체화된 재료특성으로 기존 PVC망에 비해 최대지지하중이 높게 나타났으며, 현장시험의 흡수가능에너지 또한 높게 나타나 낙석방지망의 대체재료로서 활용이 가능한 것으로 판단된다.