• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.4
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• pp.63-74
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• 1995

본 연구의 목적은 주택의 냉방 및 난방에너지 절약을 위한 적절한 식재계획의 지침을 제시하기 위함이었다. 본 연구의 대상지는 미국 중동부 내륙의 한 도시인 쉬카고(Chicago)의 북서쪽에 위치한 주거지였다. 쉬카고 는 온대 기후대에 속하는 도시로서, 본 연구는 한국 중부지역의 주택들에 있어서 식재를 통해 냉방 및 난방에너지를 절약하고, 또한 그 에너지 절약 으로부터 대기오염물의 배출을 저감하는데 유용한 정보를 제공할 것이라고 사료된다. 본 연구는 주택의 에너지 절약에 기여하는 주택주변 현존 식생 의 차양(Shading), 증발산 및 방풍의 효과를 모델링하였다. 식재로부터 절 약된 에너지의 총비용은 식생피도가 58.9%인 주거블럭에서 1993년 한해동 안 한 가구당 46.3달러였다. 그 중, 증발산효과가 53.7%, 방풍효과가 26.1%, 차양효과가 20.2%를 각각 차지하였다. 한편, 피도가 36.3%인 주거블럭에서 의 연간 총 에너지 절약은 가구당 8.6달러였다. 식생피도가 높은 주거지에 서 식재에 의한 에너지 절약의 효과는 더욱 증대되었다. 그러나, 대부분의 현존 수목은 부적지에 위치되어 겨출철에 주택내로의 광선의 입자를 차단 함으로써 난방에너지의 요구를 증가시켰다(수목 한 개체당 최대 6달러). 차 양효과를 최대화하기 위해서는 주택건물의 남쪽가까이에서는 교목의 식재 를 가급적 회피하고, 수관이 가능한 한 넓은 교목을 주택건물의 서쪽과 동 쪽가까이에 식재하여야만 한다. 증발산과 방풍의 효과를 증진하기 위해 건 물의 북쪽, 북동쪽 및 북서쪽에서의 고밀도 식재가 요구된다.

• Journal of Surface Science and Engineering
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• v.37 no.6
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• pp.319-325
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• 2004

Fe thin films containing Si particles were prepared on metallic substrates by electrodeposition method in sulfate solutions and the content of codeposited Si particles in the films was investigated as a function of applied current density, the content of Si particels in the solution, solution pH, solution temperature and concentration of $FeSO_4$$7H_2$O in the solution. The amount of Si codeposited in the film was not dependent on the applied current density, solution pH and solution temperature, while it was dependent on the content of Si particles in the solution and the concentration of $FeSO_4$$7H_2$O in the solution. The amount of Si codeposited in the film increased with increasing content of Si particles in the solution but reached a maximum value of about 6 wt% when the content of Si particles in the solution exceeds 100 g/l. On the other hand, the content of Si codeposited in the film increased up to about 17 wt% with decreasing concentration of $FeSO_4$$7H_2$O in the solution. These results would be applied to the fabrication of very thin Fe-6.5 wt% Si sheets for electrical applications.

• Korean Journal of Metals and Materials
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• v.50 no.2
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• pp.122-128
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• 2012

Water model experiments were carried out to understand the mixing behavior of reducing agents in molten slag through vortex stirrer, which makes use of a gravitational energy to mix reducing agent in the molten slag without imparting artificial energy. At a water flow rate of 6 L/min vortex was not generated, and a stable vortex was formed when the water flow rate was 7 L/min or higher with the present experimental apparatus. Water level increased linearly with increasing the water flow rate. In the upper vortex region, the vertical and horizontal velocities slightly decreased with increasing the water flow rate, whereas those in the lower vortex region increased remarkably. Accordingly, strong mixing behavior was obtained in the lower vortex region. Owing to the strong centrifugal force, particles move downwards with approaching the funnel wall. When 40 grams of polypropylene particles added to the lower vortex, they were instantaneously mixed well.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.9
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• pp.36-43
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• 2019

Turning, a main machining process, is a widespread process in metal cutting industries. Many researchers have investigated the effects of process parameters on the machining process. In the turning process, input variables including cutting speed, feed, and depth of cut are generally used. Surface roughness and electric current consumption are used as output variables in this study. We construct a simulation model for the turning process using a neural network, which predicts the output values based on input values. In the neural network, obtaining the appropriate set of weights, which is called training, is crucial. In general, back propagation (BP) is widely used for training. In this study, techniques such as ant colony optimization (ACO) and particle swarm optimization (PSO) as well as BP were used to obtain the weights in the neural network. Particularly, two combined techniques of ACO_BP and PSO_BP were utilized for training the neural network. Finally, the performances of the two techniques are compared with each other.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.234-243
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• 2018

Since September 2017, a small diesel vehicle certification test mode has been enhanced from NEDC to WLTC. The main reason for the change of the certification test mode is that the certification test mode of the emission control standard of the diesel vehicle does not sufficiently reflect various driving patterns of the actual roads. Several automakers have developed after-treatment systems such as LNT, SCR, and DPF to meet enhanced emissions regulations. In this study, four small diesel cars were selected for sale in Korea, and the exhaust gas measurement test was performed in the WLTC mode, which reflects the driving characteristics of the actual roads. As a result of test, LNT vehicle exceeded Euro 6 NOx regulation and SCR vehicle satisfied Euro 6 NOx regulation. In addition, both LNT and SCR systems showed high NOX emission characteristics due to speed, RPA and Vxa. For the PN, all test vehicles were fitted with a DPF and met the Euro 6 PN regulations, with similar PN emissions results in LNT and SCR system.

• Annual Conference of KIPS
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• 2023.11a
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• pp.665-666
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• 2023

미세 물질을 포함하고 있는 광산 폐기물의 디워터링 과정(dewatering process)은 작은 입자들의 침전속도가 낮기 때문에 시간이 오래 걸리고 어려운 과정이다. 따라서 광산 폐기물이 안정적으로 침전되었는지 확인하기 위해서 디워터링 과정을 연속적으로 모니터링하는 기술이 필요하다. 이 연구에서는 kaolinite, illite, bentonite 3 종류의 점토를 3 가지 농도(0.1g/L, 1g/L, 5g/L)로 나눠서 초음파 음향 감지를 이용해 후방산란 신호를 측정했다. 그리고 측정된 신호를 활용하여 합성곱 신경망(CNN) 모델을 개발하여 점토의 분류 모델을 만드는 연구를 수행했다. 본 연구에서 보여준 CNN 의 높은 정확도는 광산 폐기물의 디워터링 과정에서 미세 광물과 미세 농도 분류 모니터링에 적합한 저렴하고 측정하기 쉬운 음향 감지의 사용 가능성을 입증했다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.2
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• pp.84-90
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• 2009

We incubated marine columnar sediments at $25^{\circ}C$ for 230 days to simulate the responses of phosphorus in the sediment which was exposed to freshwater. The incubation was composed of three different treatments (FW: freshwater, FWA: freshwater under anoxic condition, and SW: seawater as a Control). Six particulate fractions of phosphorus in sediment were obtained through sequential extraction and, for comparison, phosphate concentrations in porewater and superlying water were also determined. After the incubation, evidently higher concentrations of phosphate were found in FW and FWA compared to SW. Mass extinction of living organisms in marine sediment from freshwater shock and consequent decay of their corps probably contributed such high phosphate spike in the overlying water. Higher concentrations of BD-P(lron-bound P) were found in FW compared to SW. After exposure to the freshwater, we could determine that penetration depth of dissolved oxygen in marine sediment will be deeper. A result of increases of ferrous compounds in freshwater where contained less sulfide has been obtained. Because of these phenomena, BD-P was increased in FW. On the contrary, BD-P was decreased in FWA since poor dissolved oxygen concentration. In FWA, total amount of Leachable P(SUM of LOP) has been remarkably increased through the experiment, which strongly suggested the easy conversion of the leachable P into reactive P. This experiment has shown that most of diverse P species in marine sediment were leachable under freshwater and low oxygen condition. Therefore reclamation of natural tidalfalt and consequent freshwater introduction seems to trigger the conversion of diverse P-species to leachable P in the marine sediments, which will exert high benthic load of phosphate to the overlying water.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.271-281
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• 2001

The characteristics of the heavy metal contamination in the soils affected by the tailings of the Palbong mine have been studied. The soils in the studied area consist mostly of loam by the particle size analysis, but a little of it, located near the stream, consist of loamy sand to sandy loam, finally to loam downward. The organic contents of soils are significantly low aoom 2 percent and the pH is in acidic ranging 6.0 $\pm$ 0.1. The samples of the parent rocks, the normal soils, the tailings and the channel deposits from the studied area were chemically analysed. From the result, the heavy metal concenlration of the soils is a little Jow compared with that of the parent rocks, shows the hydrologic process of the surface and the groundwater. The contamination of the tailings from the ore mining are high in lead, copper and arsenic. In the channel deposits the concenlrations of lead and copper are abnormally high but that of arsenic is uniquely low. And most of heavy metal contamination are decreased with the distance from the mine. It is caused by the properties of the surface and the ground water during the process of the heavy metal migration. The correlation-coefficient between sand and silt contents and the concentrations of Cd, Cu and Pb are significant but the amounts of As and Hg are increased with the clay contents. The dispersion of the heavy metals with the distance shows that the concentrations of them in the soils sampled at distance of 100 m to 200 m along the stream started near the Palbong mine are extremely high compared with those from other distances. These discrepancies are significant in Cd, Cu, Pb and Hg, but low in As. All the samples contain below detection limit of Cr+6 In the present stream water the concentrations of the heavy metals are not detected. So, it is interpreted that the concentrations in the soils are caused by the activities of the mining during the operation and have been continued by the dispersion from the tailings since after the closure of the mining, especially by the surface and ground water. The concentrations are diminished with the distance from the mining site, but in the interval of 800-2000 m increases abruptly. In the soil samples counted on the dispersion direction by wind, the lowering of the concentration is relatively uniform with the distance from the mining site. So, the rapid increase of the heavy metal concentrations is presumed to have been caused by the ground-water movement. In the migration of the heavy metals, the groundwater conditions, such as pH, Eh, the contents of colloidal particles, and Mn and Fe oxides are closely involveo. Integrating with these factors, it is interpreted that the groundwater conditions which have caused the heavy metal contamination of the studied area are those that the pH is about 3 in oxidized conditions, the contents of the colloidal particles are low, and Mn and Fe oxides are not involved in the migration of the heavy metals. Meanwhile, the vegetables growing on the soils in the studied area are not affected by the contamination of the heavy metals.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.519-528
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• 2019

In 2017, Korea Institute of Geoscience and Mineral Resources (KIGAM) has excavated a trench at Yongjang-li in the city of Gyeongju to examine the evidence of fault movement related with the 2016 earthquake in unconsolidated sediments. In the trench profile, the author has observed the features of ongoing soil-forming processes and groundwater movement overlapped on the sedimentary layers. The soil formation was in its initial stage, and most of the original sedimentary layers could be observed. The color changes depending on the redox conditions and by the Mn/Fe oxide precipitation, however, were the most significant features obscuring sedimentary records. The dark Mn oxide precipitates formed at the groundwater levels often concealed the sedimentary unit boundaries. The groundwater levels varied depending on the particle sizes of the sedimentary layers contacting the groundwater, and the Mn oxide precipitates have formed at varying depths. The groundwater could move upward along the narrow pores in the fine-textured sedimentary layer more than a few meters showing the gray color indicating a reducing condition for iron.

• Journal of Conservation Science
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• v.33 no.6
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• pp.417-429
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• 2017

This study aimed at the identification of the black coating materials on the pottery surface and manufacturing technique of black burnished pottery excavated from the Pungnaptoseong, Seoul, which is estimated to be royal fortress of Beakje. According to observation of black coated surface and raw materials, potteries can be divided into two groups. The first group potteries have black inner and black surface with well-selected particles. Second group potteries are black in surface only with unevenly selected particles. Each group seems to represent different manufacturing technique in clay selection, color development timing and method. The black burnished pottery contains high values of CaO, $P_2O_5$, L.O.I. and lower content of $Fe_2O_3$ compared with gray pottery excavated from the same site, which indicates plant ashes were used for coloring the surface of pottery in black. According to the result of SEM-EDS mapping of black burnished pottery, carbon was concentrated on pottery surface, while iron was concentrated on the surface of the gray pottery. Based on XRD analysis, firing temperature of the black burnished potteries were fired low temperature range at 700 to $900^{\circ}C$, and that of the gray potteries ranged from $900^{\circ}C$ to $1000^{\circ}C$.