• Journal of Forest and Environmental Science
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• v.6 no.1
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• pp.8-17
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• 1989

Recent development of industry and urbanization in the interior of mountainous area increases the possibility of occurence of natural disaster, such as flood, landslide and deblis-flow. Erosion control facilities, which were the most significant activity to riverbed fixiation, were constructed at the downstream of the experimental basin. In the mountain torrents, the complex bed load transport has occurred by the drift of running water, and resulting in a formation of terrace deposits. Especially, channel migration caused by scouring and deposition frequently occurs at the wide areas of the river bed. Consequently, the unsymmetrical river bed charactristics indicate the degree of the channel migration.

• Proceedings of the Microbiological Society of Korea Conference
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• 2008.05a
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• pp.166-166
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• 2008

The tidal flat of Korea is one of the most dynamic areas in terms of sediment erosion and deposition. Tidal flats provide important food resources, ecological niche for diverse organisms and have functional role of bioremediation by mineralizing organic matters. Generally, microbes are essential constituent for biochemical transformations, such as mineralization of organic matters and biodegradation of pollutants. Understanding microbes in tidal flat sediment is necessary to understand these processes. In order to understand role of microbes in tidal flat, this study investigated prokaryotic communities by several methods such as clone library, DGGE, and pyrosequencing. In addition, quantification of microorganisms and isolation biodegrading bacteria were investigated in tidal flats of Western Coast.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.95-101
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• 2010

This paper is results of case study on characteristics of debris flow occurred at Jecheon during a heavy rainfall in 2009. The site studied is the mountain area located at Palsong-ri Bongyang-op in Jecheon-si where serious damages due to debris flow were occurred by heavy rainfall during July 7 to July 16 in 2009. Intensity and duration of rainfall causing debris flow were analyzed on the basis of AWS data. Characteristics of debris flow such as initiation, transportation and deposition were investigated through field reconnaissance. The geological and topographical characteristics of slope where debris flow was triggered were figured out and characteristics of erosion on the bottom and sides of valley during transportation of debris flow were also investigated. The slope and boundary of valley where the debris flow started to be deposited were studied.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.869-872
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• 2009

Double-doped magnetic particles that incorporated magnetites into both the surface and inside the silica cores were fabricated via the sol-gel reaction of citrate-stabilized magnetites with silicon alkoxide. Double-doped magnetic particles were easily fabricated and exhibited an higher magnetism in comparison to the singledoped magnetic particles that were prepared by the erosion of surface-deposited magneties from double-doped magentic particles. Thin gold layer was formed over magnetic silica nanospheres via nanoseed-mediated growth of gold clusters. The plasmon-derived absorption bands of double-doped magnetic silica-gold nanoshells were more broadened and shifted down by ca. 20 nm as compared to those of single-doped magnetic silicagold nanoshells, which were attributed to not only the surface scattering of incident light due to relatively rough surafce morphology, but also heterogeneous permittivity of dielectric cores due to surface-deposited magnetites.

• Journal of Surface Science and Engineering
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• v.41 no.6
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• pp.274-278
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• 2008

3-dimensional numerical analysis for a rectangular magnetron cathode model is done to predict cooling characteristics of high power sputtering system for ZnO deposition. It includes cooling channel design, heat transfer analysis of a target, bonding layer and backing plate. In order to model erosion profiles of a target, ion current density distribution from 3D Monte Carlo simulation is used to distribute total sputtering power to 5 discrete regions. At 3 kW of sputtering power and cooling water flow of 1 liter/min at $10^{\circ}C$, the maximum surface temperature was $45.8^{\circ}C$ for a flat new target and $156^{\circ}C$ for a target eroded by 1/3 of its thickness, respectively.

• Journal of Wetlands Research
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• v.5 no.1
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• pp.53-66
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• 2003

The subject of sediment transport has been studied for centuries by engineers and river morpohologists. Many of the complex aspects of sediment transport are yet to be understood, and remain among the challenging subject for future studies. In this study, the finite element model is applied to various hypothetical channels. On the basis of the flow analysis results, sediment transport analysis is conducted using 3-different optional equations, and the results are compared with experimental results. For the purpose of predicting the sediment movements in natural river, RMA model is applied to Geum-River. It turned out to be very effective tool to predict various aspects of river evolution and the effects of hydraulic structures. The simulation results are also linked to the Geographic Information Systems (GIS).

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.9
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• pp.527-532
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• 2000

The performance of ac plasma display panels (PDP) is influenced strongly by the surface glow discharge characteristics on the MgO thin films. This paper deals with the surface glow discharge characteristics and some physical properties of MgO thin films prepared by reactive RF planar unbalanced magnetron sputtering in connection with ac PDP. The samples prepared with dc bias voltage of -10V showed lower discharge voltage and lower erosion rate byion bombardment than those samples prepared by conventional magnetron sputtering or E-beam evaporation. The main factor that improves the discharge characteristics by bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardement during deposition process.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.111-116
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• 2010

In a large area magnetron sputtering system, which is under the influence of high heat load from the plasma, it is necessary to use the effective water cooling in order to maintain the proper deposition performance and the economic use of target materials. A series of three-dimensional numerical simulations are carried out on the simplified model of the large area magnetron sputtering system with the cooling plate that includes the U-shaped water channel. The analysis is focused on the effects of water channel geometry, cooling water flowrate, thermal conductivity of target material, and the degree of target erosion on the cooling performance of cooling plate, which is represented by the temperature distribution of target material.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.295-299
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• 2011

자연계에서 토양의 침식 및 퇴적 반복적 과정은 매우 복잡한 형태로 발생하며, 호우로 인한 토사유출은 유역의 지형 및 지질학적 특성과 수문기상학적 특성 등에 의해 매우 민감하게 반응한다. 즉, 토양 침식 및 퇴적은 유역의 형상, 토양종류, 토지 이용 및 피복상태, 강우사상 등에 따라 시 공간적 분포가 다양하게 변화한다. 따라서 유역내 침식 및 퇴적의 시·공간적 변동성을 분석하기 위해서는 지형학적 특성인자와 수문기상학적 특성인자에 따른 유역내 수문학적 응답을 이해해야 한다. 본 연구에서는 분포형 강우-유사-유출 모형을 이용하여 용담댐 상류 천천유역을 대상으로 Strahler 하천차수구분법에 의해 유역을 차수별 소유역으로 구분하고, 지형학적 특성인자(유역면적, 지표흐름 이동거리, 국부경사)와 수문학적 특성인자(총 강우량)에 따른 침식 및 퇴적의 공간분포 변화에 대하여 분석하였다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.2
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• pp.235-243
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• 2019

Radioactive materials are released into the air and deposited on the surface soil after a nuclear accident. Radionuclides deposited in soil are transported by precipitation to nearby environments and contaminate the surface water system. Basic data on surface watershed and soil erosion models have been collected and analyzed to evaluate the behavior of radionuclides deposited on surface soil after a nuclear accident. Data acquisition and analysis in aquatic environment were performed to investigate the physical characteristics and variation of biota in rivers and lakes of the Nakdong river area near the Wolsong nuclear power plant. For these purposes, a digital map, and hydrological, water quality and biota data were gathered and a systematic database (DB) was constructed in connection with them. Constructed aquatic DB will be supplied and used in surface watershed and soil erosion models for investigation of long-term movement of radionuclides in adsorptive form in surface soil. Finally, basic data and established models will be utilized for general radiological impact assessment in aquatic environment.