• Conservation Science in Museum
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• v.14
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• pp.37-60
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• 2013

Conservation and analysis of wall painting Goguryeo was performed to classify the unknown fragments. The conservation naked eye observation, optical microscopy, and infrared examination were carried out in order to figure out the structure, quality of constituting materials, and damages such as cracks, and discolored fragments of colored areas. Based on such investigation, conservation was proceeded. and it was completed with strengthening the weakened pigment layer of wall blocks. In addition tombs where the wall painting fragments were excavated were investigated by making comparison with gelatin dry plates and copies possessed by National Museum of Korea. According to the result, they were Kaemachong, Gosan-ri Tomb No.1 Gamsinchong, and Wonbong-ri Tomb. The components of colors with which Goguryeo wall painting fragments were painted and the mineral pigments of the wall layer were analyzed. Portable µ-XRF spectrometer and X-ray diffractometer were employed. It showed that lime (CaCO₃) used for the wall layer, and the brown color is hematite(Fe₂O₃) and cerusite (PbCO₃) and lead oxide(PbO) were identified. In the red color, cinnabar (HgS) were detected.

• Resources Recycling
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• v.25 no.6
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• pp.41-49
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• 2016

The present study was intended to prepare cobalt oxide ($Co_3O_4$) powder of average particle size 50 nm or less by spray pyrolysis reaction using the raw cobalt chloride ($CoCl_2$) solution, in order to identify the change in the nature of the particles according to the change in the nozzle tip size. When the nozzle tip was 1 mm, it turned out that most of the droplets were spherical and the surface showed very tight structure. The average particle size of the finally formed particles was 20-30 nm. When the nozzle tip size was 2 mm, some of the droplets formed were spherical, but a considerable part of them showed severely disrupted form. particles formed showed an average particle size of 30 - 40 nm. For the nozzle tip size of 5 mm, spherical droplets were almost non-existent and most were in badly fragmented state. The tightness of surface structure of the droplets has greatly been reduced compared with other nozzle tip sizes. Average size of the formed particles was about 25 nm. As the nozzle tip size increased from 1 mm to 2 mm and 3 mm, the intensities of the XRD peaks have changed little, but significantly been reduced when the nozzle tip size increased to 5mm. As the nozzle tip size increased from 1 mm to 2 mm, the specific surface area of the particles decreased, but the nozzle tip size increased to 5mm, the specific surface area remarkably increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.784-789
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• 2012

In this paper, a number of anode and reference electrodes that are installed around the target anti-corrosion objects to monitor, appropriate to your situation of a fixed potential and polarization methods can be applied automatically in the system was developed. In particular, this system was configured with a remote electric anti-corrosion automatic control device that have automatically adjust function to uniformal anti-corrosion in all parts of target objects, a corrosion monitoring device to perform the function of corrosion potential detection and a web-based operating program to perform the function of real-time monitoring, control and prediction. Using this system, by preventing oxidative corrosion phenomena can maximize the life of the target anti-corrosion objects.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.127-132
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• 2012

In this paper, the edge effects of proposed structure in active region for high voltage in shallow trench isolation for very large integrated MOSFET were simulated. Shallow trench isolation (STI) is a key process component in CMOS technologies because it provides electrical isolation between transistors and transistors. As a simulation results, shallow trench structure were intended to be electric functions of passive, as device dimensions shrink, the electrical characteristics influence of proposed STI structures on the transistor applications become stronger the potential difference electric field and saturation threshold voltage.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.407-407
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• 2012

화학기상증착법(CVD; Chemical Vapor deposition)으로 h-BN을 증착하여 성장 시간에 따른 표면의 특성 및 결정성을 연구하였다. 암모니아 보레인(BH3NH3)을 보론 나이트라이드(Boron Nitride) 박막의 전구물질로 이용하였으며, $70{\sim}120^{\circ}C$로 열을 가하여 열분해하였다. $25{\mu}m$ 두께의 구리 기판을 챔버에 넣어서 Low pressure (~25 mTorr) 상태가 되도록 한다. 25 mTorr 이하의 압력에서 수소 가스 (0.2~1sccm)를 넣고 $20^{\circ}C$/min로 가열한 후 약 한 시간 후에 $990{\sim}1,000^{\circ}C$가 된다. 그 후 Cu foil의 표면을 부드럽게 하고, 산화막을 제거하기 위해 $990^{\circ}C$에서 40 분간 열처리(annealing)한다. 그 후 암모니아 보레인에서 분해된 보라진 가스(borazine; B3H6N3)로 h-BN을 합성한다. 성장 시간이 길수록 더 많은 부분이 보론 나이트라이드에 의해 덮인다는 것을 관찰하였고, 성장 시 주입하는 수소의 양(0.2~5 sccm)과 알곤(0~15 sccm)의 혼합 비율에 따라 보론 나이트라이드의 domain size가 변화함을 알 수 있었다. 그 각각의 차이를 주사 전자현미경(SEM; Scanning Electron Microscopy)을 통해 확인하고, 결정성을 라만 분광(Raman spectroscopy), 광전자 분광(XPS; X-ray photoelectron spectroscopy)으로 비교 분석하였다.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.44-52
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• 2006

Bio-filtration processes using honeycomb tubes (process 1) and aeration and manganese-sand filtration (process 2) were evaluated for the biological manganese removal efficiency. The concentration of manganese at effluent was stabilized after 20days operation in process 1. It was estimated the required time for attaching and growing microorganisms to honeycomb tubes. In long term of operation periods, manganese removal efficiency was dropped for the excessively attached biofilm and manganese dioxide to honeycomb tubes. It took several days for normal operation in process 2, after that manganese removal efficiency was increased to 98% and stabilized for 1.5 years. Microorganisms in process 1 and 2 were isolated and cultured to characterize manganese-oxidizing bacteria. Among the four types of colony, light brown colony was turned blue color by leuco crystal violet spot test. Stenotropomonas genus, known as manganese-oxidizing bacteria, was identified by 16S rDNA partial sequencing analysis which was isolated in process 1 and 2. For the biological treatment to remove manganese, these two considerations are important. One is to choose the proper media attaching manganese oxidant, another one is to define the cultural condition of isolated manganese-oxidizing bacteria.

• Journal of the Korean Society of Combustion
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• v.13 no.2
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• pp.23-32
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• 2008

Gasification characteristics in the fluidized bed reactor are essential for the design of a gasification furnace to optimize the operation condition. Moisture content of the solid fuel is one of the important factors to influence directly the gasification characteristics. So it is necessary to investigate the effect of moisture content of solid fuel in partial oxidation condition. Gasification characteristics are investigated with results from thermogravimetric analyzer and lab-scale fluidized bed reactor for wood and RDF samples along with changing moisture contents. Additionally lab-scale fluidized bed reactor was run continuously and gas concentrations at the exit were measured. It is observed that the rate of reaction in partial oxidation condition is between the results from the combustion environment and from the inert condition. Moisture content in a particle slows down the heating rate of a particle. So, reaction is delayed by the moisture content. However, RDF samples those are easy to break-up don't show the effect of moisture content. The result of continuous operation condition shows that proper moisture content promotes gasification because steam from the particles helps gasification of the solid fuel. A simulation to predict the syn-gas composition was conducted by the Aspen Plus process simulator. The cold gas efficiency of the experiment was compared with results from the simulation.

• Economic and Environmental Geology
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• v.34 no.5
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• pp.437-446
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• 2001

Zoned epidotes formed by the propylitic alteration of the Bobae sericite deposit in western Pusan show complex compositional zoning patterns, such as multiple growth zoning, oscillatory zoning, patchy zoning and irregular zoning. The complex zoned epidote, in general, shows AI-rich cores and Fe-rich rims. Pistacite component (Ps) in the epidote ranges from 18.5 to 74.3 mot.%. Remnant textures in multiple growth zoning indicate that the earlier zone was partially resorbed prior to growth of later one. Multiple growth zoning and oscillatory zoning suggest that hydrothermal system underwent rapid changes and fluctuations in fluid chemistry, redox condition, or temperature.

• The Korean Journal of Quaternary Research
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• v.10 no.1
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• pp.27-52
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• 1996

금강 퇴적물의 지화학적 특성을 파악하기 위하여 상류에서 하류까지 21개의 표층 퇴적물을 채취하고 총금속(Al, Fe, Mn, Cr, Co, Ni, Cu, Zn, Pb) 입도별 금속 및 존재형태별 금속을 분석하였다. 또한 하천에서 연안역까지 미량금속의 공간적 변화를 보기 위해 부유물 을 일정 간격으로 채취하여 미량금속을 분석하였다. 퇴적물 중 미량 금속 함량을 평균 입도 와 밀접히 관계하여 변화하며 세립질실트 이하 부분에서 가장높은 함량을 보였고 이 높은 함량은 하천 부유물 중 금속 함량과 Mn을 제외하고 거의 유사한 수준이었다. Pb은 조립질 모래에서도 높은 함량을 보이는데 이는 조립질 모래에 많이 포함된 정장석에 의한 영향이 되고 세립질 실트에서의 높은 금속 함량은 세립한 중광물에 의한 영향이다. Mn과 Pb을 제 안한 금속들은 퇴적물 중 주로(70% 이상) 결정 격자와 관계하여 존재하는데 이는 퇴적물의 주구성 입도가 조립하여 금속이 풍부하고 세립한 중광 물에 의한 영향이 크기 때문이다. 하 천에서 염하구로 금속 함량이 급격히 감소하는데 이는 용존 $Mn^{+2}$이온이 $MnO_2$로 변화하는 산화반응과 하천구역에서의 퇴적 그리고 염하구에서 금속이 적어 진 입자(염하구 내에서 유기물 분해/용해로 만들어지거나 재부유 작요에 의한 조립질 물질) 와 하천 부유물과의 혼합작용에 의해 이루어진다.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.56-61
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• 2005

Methanol was synthesized by homogeneous and catalytic reactions of partial oxidation of methane. The effect of pressure, temperature and oxygen concentration on methanol synthesis was investigated. The catalyst used was Bi-Cs-Mg-Cu-Mo mixed oxide. The partial oxidation reaction was carried out in a fixed bed reactor at 20${\sim}$46 bar and $450{\sim}480^{\circ}C$ and oxygen concentration of 5.3${\sim}$7.7mol%. The results were compared with results of homogeneous reaction performed at the same conditions. Methane conversions of the homogeneous and catalytic reactions increased with temperature. Methanol selectivity of the homogeneous reaction decreased with increasing temperature. However, the methanol selectivity of catalytic reaction increased with temperature. For both homogeneous and catalytic reactions, the methane conversions were around 5%. This may be due to the low oxygen concentration. Methanol selectivity of the catalytic reaction was higher than that of homogeneous one.