• Journal of the Korean Geosynthetics Society
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• v.12 no.3
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• pp.65-73
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• 2013

The information of cut slope in Mt. Jang area, Busan is investigated in order to construct the Slope Management System in Urban Area. The slope inspection sheet is made to record the characteristics for cut slopes, and that is capable to be inputted slope information systematically. The cut slopes in Mt. Jang area are consisting of 69 slopes. Most of the cut slopes are constructed in cutting slope and retaining wall (CR). The cut slopes located in housing facilities are 46 slopes, and the slopes located in school facilities are 12 slopes. The traverse of cut slopes is mainly ranged from 50 m to 150 m, and the height is mainly ranged from 10 m to 20 m. The slopes combined with soil and rock are mostly distributed. The retaining wall was installed in the toe part of cut slope in order to increase the slope stability, and the additional reinforcement methods including the anchor, drainage, preventing rock fall, shotcrete and vegetation were installed at the toe part of cut slopes.

• The Journal of the Petrological Society of Korea
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• v.6 no.1
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• pp.1-18
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• 1997

Andesitic pyroclastics and lava flows are deposited as a part of composite volcanoes by Cretaceous volcanic activity in Geojae Island, off the coast of Korea. The andesitic pyroclastics are composed of tuff breccia and lapilli tuff minor intercalated tuff. Lava flows are divided into dense and porphyritic andesite containing phenocrysts of plagioclase, pyroxene, and/or hornblende. The andesitic rocks represent charactersitcs of carc-alkaline BAR association with basalt, basaltic andesite, andesite, and dacite to rhyolite. Major element variations of the volcanic rocks show that $Al_2O_3$, total FeO, CaO, MgO and $TiO_2$ decrease with increasing $SiO_2$ but $K_2O$ and total alkalis increase, and represent differntiation trend of calc-alkaline rock series. In spider diagram, contents of Sr, K, Rb, Ba, and Th are relatively high, but contents of Nb, P, Ti and Cr are low. These petrochemcial characteristics are similar to those of rocks from island arc or continental margein related to plate subduction. Chondrite-normalized REE patterns of volcanic rocks are paralle to subparallel, with LREE enriched than HREE, and show gradual increase of negative Eu anomaly from basalt to dacite and rhyolite, suggesting comagmatic fractional crystallization with minor effects of assimilation and magma mixing. Andesitic rocks are assumed medium-K orogenic andesites that formed in the tectomagmatic environment of subduction zone under normal continental margin arc.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.623-630
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• 2006

The slag viscosity is an important factor determining the operation temperature of entrained flow type of gasifiers. The temperature of critical viscosity, $T_{cv}$, for 5 crystalline slags was predicted by empirical models and FactSage equilibrium calculations, and the validity of each method was tested. Two empirical models were employed: one using $T_h$ from the ash fusion test, and the other using the concentrations of 5 major components. The first model using $T_h$ over-predicted $T_{cv}$ by $20{\sim}100^{\circ}C$, while the model based on the slag composition under-predicted $T_{cv}$ by $80{\sim}120^{\circ}C$. In the equlibrium calculations, $T_{cv}$ was obtained from the liquidus temperature. When the 4-major component concentrations were used in the calculation, the predicted temperatures were higher than the observed. The liquidus temperature was very sensitive to the concentrations of minor components, and the addition of MgO and $Na_2O$ lowered the liquidus temperature. The results with 4 major and 3 minor components most closely described experimentally observed $T_{cv}$. In the case that a chromia refractory was used, it was shown that $Cr_2O_3$ concentration in the slag also needs to be included for more accurate prediction of $T_{cv}$.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.281-290
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• 2018

As the internal combustion engine vehicles of high fuel efficiency and low emission are demanded, it becomes important to procure technologies for improving low-temperature performance of automotive catalyst systems. In this study, we showed that the combustion rate of diesel particulate matter is greatly enhanced at low temperature by applying fuel-borne catalyst and perovskite catalyst concurrently. It was tried to examine the correlation between elemental composition of perovskite catalyst and combustion activity of mixed catalyst system. To achieve this goal, we applied temperature-programmed oxidation technique in testing the combustion behavior of perovskite-mixed particulate matter bed which contained the element of fuel-borne catalyst or not. We tried to explain the synergetic action of two catalyst components by comparing the trends of concentrations of carbon dioxide and nitrogen oxide in temperature-programmed oxidation results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.80-85
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• 2019

Vanadium dioxide is a well-known metal-insulator phase transition material. Lots of researches of vanadium redox flow batteries have been researched as large scale energy storage system. In this study, vanadium oxide($VO_x$) thin films were applied to cathode for lithium ion battery. The $VO_x$ thin films were deposited on Si substrate($SiO_2$ layer of 300 nm thickness was formed on Si wafer via thermal oxidation process), quartz substrate by RF magnetron sputter system for 60 minutes at $500^{\circ}C$ with different RF powers. The surface morphology of as-deposited $VO_x$ thin films was characterized by field-emission scanning electron microscopy. The crystallographic property was confirmed by Raman spectroscopy. The optical properties were characterized by UV-visible spectrophotometer. The coin cell lithium-ion battery of CR2032 was fabricated with cathode material of $VO_x$ thin films on Cu foil. Electrochemical property of the coin cell was investigated by electrochemical analyzer. As the results, as increased of RF power, grain size of as-deposited $VO_x$ thin films was increased. As-deposited thin films exhibit $VO_2$ phase with RF power of 200 W above. The transmittance of as-deposited $VO_x$ films exhibits different values for different crystalline phase. The cyclic performance of $VO_x$ films exhibits higher values for large surface area and mixed crystalline phase.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.809-817
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• 2008

This paper deals with the development of ViscoElastic Continuum Damage Finite Element Program (VECD-FEP++) and its verification with the results from both field and laboratory accelerated pavement tests. Damage characteristics of asphalt concrete mixture have been defined by Schapery's work potential theory, and uniaxial constant crosshead rate tests were carried out to be used for damage model implementation. VECD-FEP++ predictions were compared with strain responses (longitudinal and transverse strains) under moving wheel loads running at different constant speeds. To this end, an asphalt pavement section (A5) of Korea Expressway Corporation Test Road (KECTR) instrumented with strain gauges were loaded with a dump truck. Also, a series of accelerated pavement fatigue tests have been conducted at pavement sections surfaced with four asphalt concrete mixtures (Dense-graded, SBS, Terpolymer, CR-TB). Planar strain responses were in good agreement with field measurements at base layers, whereas strains at both surface and intermediate layers were found different from simulation results due to the complexity of tire-road contact pressures. Finally, fatigue characteristics of four asphalt mixtures were reasonably described with VECD-FEP++.

• KSBB Journal
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• v.8 no.5
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• pp.431-437
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• 1993

Active carbon which has the smallest bulk and wet density was found as the best support media among 4 different kinds of materials(celite, natural zeolite, Pusuk stone, active carbon) to make a proper fluidized-bed with small energy consumption. Its minimum and optimum fluidization velocity were found as 0.03cm/sec and 0.25cm/sec, respectively. As organic loading rate for methane fermentation was increased, CODcr removal efficiencies of all the media were decreased. But, CODcr, removal efficiencies of active carbon was maintained more than 90% in this experimental range of the organic loading rate. Larger amount of microorganism was adsorbed on the active carbon which has very high specific surface area. At the organic loading rate of 16g CODcr,/l day, its adsorbed cell mass was 157mg/g. Comparing natural zeolite with roast celite, adsorbed cell mass did not increase in proportion to specific surface area of the media. Even though roast celite has the same specific surface area as the Pusuk stone, its organic removal ability was superior to that of the Pusuk stone, which explains that the relatively great surface roughness and the positive surface charge are important for cell adsorption. It was concluded that the support media for anaerobic fluidized reactor should have small wet density and small fuidization velocity, if possible, in order to increase cell adsorption by reducing the fluid shear stress.

• Proceedings of the Turfgrass Society of Korea Conference
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• 2011.02a
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• pp.25-32
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• 2011

본 연구는 화력발전의 부산물로 발생하는 석탄바닥재가 골프장 사질 토양의 개량재로 사용 적합한지를 평가하기 위해 수행되었으며, 결과를 요약하면 다음과 같다. 1. 석탄바닥재의 화학성을 분석한 결과 총질소 0.34%, 가용성 인산 $52mgL^{-1}$, 치환성 칼륨 $51mgL^{-1}$ 뿐만 아니라 소량의 치환성 칼슘과 마그네슘을 함유하고 있어 식물생육에 이롭고, 유해중금속함량은 Cd, $Cr^{6+}$, Pb, Ni, As는 $1mgL^{-1}$ 이하, Cu 농도는 $1.25mgL^{-1}$ 검출되어 토양환경보전법의 토양오염우려기준 이하이므로 석탄바닥재 재활용으로 인한 토양오염 가능성은 매우 낮은 것으로 판단된다. 2. 모래 토양에 석탄바닥재를 부피비로 0~50% 비율로 혼합한 시료의 투수계수와 유효수분함량을 측정한 결과 석탄바닥재 혼합비율이 증가할수록 투수계수는 유의성 있게 감소하고 유효수분함량은 유의성 있게 증가해 석탄바닥재가 모래 토양의 낮은 수분보유력을 개선하는 효과가 있음을 확인하였다. 3. 모래 토양에 석탄바닥재를 부피비로 0~50% 비율로 혼합한 시료를 잔디식재층으로 조성한 라이시미터에 잔디종자 파종 후 약 4개월 뒤 잔디밀도가 완전히 형성된 후에 시비 후 3일 간격으로 채취한 용탈수를 분석한 결과 1일과 4일 후에 채취한 초기 용탈수에서는 석탄바닥재 혼합비율이 높을수록 $NO_3-N$, $NH_4-N$ 및 K함량이 유의성 있게 감소했으며, 대조구에 비해 석탄바닥재 혼합비율이 높은 처리구일수록 $NO_3-N$, $NH_4-N$ 및 K함량이 용탈수 채취기간 동안 지속적으로 용탈되었다. 이 결과로 석탄바닥재가 모래 토양의 낮은 양분 보유력을 개선하는데 효과적이고 석탄바닥재처리가 대조구에 비해 오랫동안 식물 생육에 필요한 양분을 공급하는 효과가 있음을 확인하였다. 4. 골프장 그린상구조와 동일한 시험포장을 만들고 모래 토양에 석탄바닥재 10%와 20% 그리고 피트, 액시스, 이소라이트를 부피비로 10% 비율로 혼합한 시료를 잔디식재층으로 조성하고 크리핑 벤트그래스(Agrostis paulstris Huds), Penn A-4 $10gm^{-2}$을 파종한 후에 처리구별로 잔디 품질을 평가하기 위해 잔디 밀도, 뿌리길이, 색상 및 시각적 품질을 조사한 결과 석탄바닥재 처리구는 기존에 사용하는 개량제인 피트, 액시스, 이소라이트 처리구와 동등한 잔디생육 촉진 효과가 있는 것으로 조사되었다. 5. 결론적으로 석탄바닥재는 골프장 토양의 물리적 특성과 화학적 특성을 개선하고 잔디생육에 필요한 양분을 공급하는데 효과적인 토양개량재라고 할 수 있다.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.53-62
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• 2002

The physical and chemical properties of cover soils of 10 waste landfill sites in Kyonggi-Do area, where social circumstances at present forces to consider the reuse of landfill, were investigated to provide the informations of soil environment which are necessary to establish the appropriate ecological restoration plan of waste landfills. The pH and electrical conductivity of soils were higher in landfills sites than in reference sites (area around landfill sites), indicating the salt accumulation in surface soil. However, total-N and organic matter contents were lower in landfills sites than in reference sites. In landfill sites, the total-N and plant available-P contents were less than 0.15% and 20mg/kg, respectively. Exchangeable cations (K, Ca, Mg and Na) and heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) contents varied between the landfill sites, but were higher in landfills sites than in reference sites. The major exchangeable cation of soil was Ca. Heavy metal contents were much lower than the critical concentration which phytotoxicity is considered to be possible and the standard for agricultural land of Korean Soil Environmental Preservation Act. Therefore, the proper soil management plan to increase the soil fertility is recommended for the ecological restoration of landfill using natural or artificial vegetation.

• The Journal of the Petrological Society of Korea
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• v.24 no.4
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• pp.307-321
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• 2015

The study area, Bophi Vum, Myanmar, is composed of the harzburgite, serpentinite and dunite, those are covered by Quaternary alluvium. The chromite ore bodies are developed within dunite and harzburgite bodies, mainly within dunite bodies. To identify the extension of the chromite ore bodies, we carried out trench surveys in the 5 different sites. The chromite ore bodies have 0.3-1.5 m wide, and several meters of extension, and deformed strongly as a sigmoid and a boudin shapes with dunite and harzburgite bodies by ductile deformation. The ductile deformation have a top-to-the-west shear sense, indicating the existence of a westward thrusting. The NW-SE trending distribution of ore bodies is related to the dextral ductile shearing and/or to the block rotation as a book-shelf structure by dextral strike-slip movement.