• Korean Journal of Materials Research
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• v.4 no.1
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• pp.63-74
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• 1994

The ultrathin oxide films less than 100$\AA$ were grown by thermal oxidation in $N_2O$ ambient to improve the controllability of thickness, thickness uniformity, process reproducibility and their electrical properties. Oxidation rate was reduced significantly at very thin region due to the formation of oxynitride layer in $N_2O$ ambient and moreover nitridation of the oxide layer was simultaneously accompanied during growth. The nitrogen incorporation in the grown oxide layer was characterized with the wet chemical etch-rate and ESCA analysis of the grown oxide layer. All the oxides thin films grown in $N_2O$, pure and dilute $O_2$ ambients show Fowler-Nordheim electrical conduction. The electrical characteristics of thin oxide films grown in $N_2O$ such as leakage current, electrical breakdown, interface trap density generation due to the injected electron and reliability were better than those in pure or dilute ambient. These improved properties can be explained by the fact that the weak Si-0 bond is reduced by stress relaxation during oxidation and replacement by strong Si-N bond, and thus the trap sites are reduced.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.494-499
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• 2006

LSIV (Large Scale Image Velocimetry)는 영상 처리 기술을 이용하여 수표면의 유속을 측정하는 장비이다. 처리가 용이한 좋은 LSIV의 영상을 만들기 위해서는 높은 고도에서 내려다 보며 영상을 획득하는 것이 측정의 정밀도를 높이는 데 도움이 된다. 이를 위해 트럭에 장착된 기중기를 이용하는 이동용 LSIV를 개발하고 있다. 이 때 기중기의 흔들림에 따라 획득된 영상이 흔들리는 문제가 발생하며, 영상의 흔들림을 보정하여 유속을 측정할 수 있는 영상 처리 알고리듬이 필요하게 된다. 이 연구에서는 PTV(Particle Tracking Velocimetry)의 입자 추적 알고리듬과 LSIV의 좌표 변환 알고리듬, LSIV의 유속 산정 알고리듬을 조합하여 흔들리는 영상에서 표면 유속을 측정하는 알고리듬을 개발하였다. 입자 추적 알고리듬은 비디오 카메라로 촬영된 연속 영상의 참조점들의 움직임을 추적하여 카메라의 위치 변동을 파악한다. 영상 분석된 결과들을 이러한 참조점들을 기준으로 변환하였다. 개발된 알고리듬의 검증을 위해서 실험 수로에서 동일한 흐름에 대해 흔들리지 않은 영상과 흔들리는 영상의 두 가지 영상을 만들었다. 흔들림이 없는 영상의 처리결과를 기준으로 삼아, 흔들림이 있는 영상의 처리 결과를 검토하였다. 그 결과, 흔들림이 지나치게 커서 참조점들의 추적이 불가능한 경우를 제외하고는 두 자료의 처리 결과는 거의 동일하였으며, 유속 측정의 최대 오차는 약 5 % 내외로 나타났다. 이 오차는 흔들림 때문에 생기는 영상의 열화 때문으로 추정된다. 이 알고리듬은 이동용 LSIV 시스템에 효율적으로 활용될 수 있을 것으로 기대된다.비용적 측면이나 생태 보존적 측면에서 유리할 것으로 판단된다.one)을 설치하는 대책이 필요하다. 저수지 관리를 효과적으로 수행하기 위해서는 저수지 내부의 탁도 거동을 정확히 예측할 수 있어야 한다. 따라서 추후 동수역학 및 열역학에 기초한 3차원 수치모형 연구와 성층흐름에 정밀한 밀도류 실험연구 및 이에 대한 적용이 필요할 것으로 판단된다.함으로써 정보의 질적보장과 정보전환의 표준화방안을 제시하는 정보분석시스템이다.이용, 수자원의 지속적 확보기술의 특성에 따른 4개의 평가기준과 26개의 평가속성으로 이루어진 2단계 기술가치평가 모형을 구축하였으며 2개의 개별기술에 대한 시범적용을 실행하였다.하는 것으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익

• Fire Science and Engineering
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• v.30 no.2
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• pp.35-42
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• 2016

The membrane structure provides high satisfaction with lightweight, improved workability, reduced cost, and a free shape. Thus, its applications expanding. On the other hand, in an architectural membrane that is vulnerable to fire, the development of various architectural membranes with flame resistance is in demand. Therefore, this study applied basalt woven fabric safety for flame resistance, excellent heat insulation and thermal properties on an architectural membrane. The PTFE- coated basalt woven fabric membrane was compared with a PTFE coated glass fiber membrane by DSC/TGA, strength properties, flammability, and incombustibility properties. In addition, this study confirmed the membrane applicability of basalt woven fabric and basalt-glass hybrid woven fabric through a comparison with existing architectural membranes.

• Composites Research
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• v.18 no.1
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• pp.23-29
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• 2005

In this work, the effect of ozone treatment of montmorillonite (MMT) on the surface characteristics of montmorillonite and the thermal stability of MMT/polypropylene (PP) nanocomposites was investigated. The surface properties of MMT were determined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). Also, the thermal stability of nanocomposites was investigated in thermogravimetric analysis (TGA). As a result, it was found that the silicate interlayers of the organically modified MMT (D-MMT) were increased by about 11${\AA}$, as compared with the MMT. Also, FT-IR showed that a new peaks at $2800\~2900\;cm^{-1}$ appeared due to the $CH_2$ mode in the D-MMT The ozone treatment of the MMT led to an increase of SiO or $SiO_2$ groups on MMT surfaces, resulting in increasing the oxygen-containing functional groups on MMT. The ozonized MMT had higher thermal stability than that of untreated nanocomposites. This was due to the improvement of interfacial bonding strengths, resulting from the acid-base interfacial interactions between PP and MMT.

• Journal of the Korean Vacuum Society
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• v.9 no.2
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• pp.162-166
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• 2000

High quality $Si_3N_4$ metal-insulator-metal (MIM) capacitors were realized by plasma enhanced chemical vapor deposition (PECVD). Titanium nitride (TiN) adapted as a diffusion barrier reduced the interfacial reaction between $Si_3N_4$ dielectric layer and aluminum metal electrode showing neither hillock nor observable precipitate along the interface. The capacitance and the current-voltage characteristics of the MIM capacitors showed that the minimum thickness of $Si_3N_4$ layer should be limited to 500 $\AA$ under the present process, below which most of the capacitors were electrically shorted resulting in the devastation of on-wafer yield. According to the transmission electron microscopy (TEM) on the cross-sectional microstructure of the capacitors, the dielectric breakdown was caused by slit-like voids formed at the interface between TiN and $Si_3N_4$ layers when the thickness of $Si_3N_4$ layer was less than 500 $\AA$. Based on the calculation of thermally-induced residual stress, the formation of voids was understood from the mechanistic point of view.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.705-708
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• 2008

To obtain tunnel concrete safety in case of fire, this study analyzed fire proof characteristics by fire proof method change, and the results are as follows. As a fire proof characteristics by RABT temperature heating curve, plain concrete experienced severe spalling by initial extremely high temperature. In view of fire proof method, in the cases of organic fiber mixing method and board method, spalling was prevented, and in the case of spray method, severe spalling of over 100mm depth occurred along with exposure of structural concrete including spray coat by heat stress, etc while metal lath, the stiffener, falls off. As for fire proof characteristics by RWS temperature heating curve, in case of organic fiber inclusion, concrete surface experienced fusion of within 5mm, while in the case of spray method, spray coat was severely spalled to a depth of over 100mm causing structural body concrete to expose its reinforcement, and also in the case of board method, board was fused by high temperature, causing structural body concrete be directly exposed to high temperature, which triggered overall fall-off phenomenon, so in such extraordinary high temperature heating condition, establishment of special fire proof measures is needed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.429-434
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• 2016

Among various De-NOx technologies, Urea-based Selective Catalytic Reduction (SCR) systems are known to be the most effective in marine diesel applications. The spraying and mixing behavior of the urea-water solution has a decisive effect on the system's net efficiency. Therefore, in this study, the spray behavior and ammonia uniformity with and without a static mixer were analyzed by CFD in order to optimize the SCR system. The results showed that the static mixer significantly affected the uniformity of velocity and ammonia concentration. Static mixers may be especially suited for marine SCR systems with space constraints.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.52-56
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• 2021

With the development of an eco-friendly environment and the automobile industry, research is being actively conducted to increase thermal efficiency and reduce exhaust gas through complete combustion in internal combustion engine vehicles. In particular, research is underway to increase engine load and output by understanding the volatility and combustion characteristics of gasoline, and research is underway to reduce soot and harmful gases and realize optimal efficiency based on the distillation and combustion characteristics of diesel fuel. . Therefore, in this study, based on the contents of KS M ISO 3045 on the distillation test method for petroleum products according to the Korean industrial standard, distillation experiments were conducted based on gasoline and diesel from 4 refineries marketed and used in Korea. The distillation experiment confirmed the correlation with the distillation temperature according to the amount of distillation, and the distillation characteristics were analyzed by comparing the distilled fuel to confirm the suitability of meeting the test standards.

• Journal of Conservation Science
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• v.25 no.1
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• pp.101-114
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• 2009

Potsherds and kilns of the AD 3th century excavated from Gundong and Majeon sites, Korea were studied to investigate the production techniques and provenance of potsherds and kilns on the pastes. For potsherds, kilns blocks and in-situ paleo-soils, provenance of raw materials were estimated through mineralogy and geochemistry, while production technique and thermal feature of kilns were investigated through observation of textures and compositions as well as firing experiment on paleo-soils. As a result of study, potsherds and kilns were found to have similar mineralogical compositions as the neighboring paleo-soils and to have same evolution path with that of geochemistry. The potsherds were divided into 3 groups according to firing temperature and production technique. Group 1 consists of reddish stamped pattern pottery with loose textures, which has many pores and contains many iron oxides. Its temper is less than about 0.5mm, and was probably fired between 700 to $800^{\circ}C$. Group 2 contains ash to grayish blue stamped pattern pottery, which has vitrified texture and few pores. Its temper is less than about 0.5mm, and was probably fired from 900 to $1,000^{\circ}C$. However, some potsherd belongs to the group 2 in terms of features for temper and pastes, but it was probably fired over $1,100^{\circ}C$. Group 3 contains reddish and grayish stamped pattern pottery. It has vitrified matrix, few pores and temper consists of polycrystalline quartz and feldspar over 2mm, and it was probably fired around $1,000^{\circ}C$. The kiln had experienced temperature from 600 to $700^{\circ}C$ on the wall, from 900 to $1,000^{\circ}C$ on the bottom, suggesting the function of high temperature firing.

• Polymer(Korea)
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• v.34 no.3
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• pp.191-197
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• 2010

To improve the curing method of anisotropic conductive film (ACF) at low temperature, it was studied to replace the thermal latent curing agent of imidazole compounds by the curing agent of cationically initiating type. Thermo-mechanical properties such as glass transition temperature, storage modulus, and coefficient of thermal expansion were investigated for the analysis of curing behavior. The reliability of ACF were observed in thermal cycle and high temperature-high humidity test. ACF using cationic initiator showed faster curing, lower CTE, and higher $T_g$ than the case of using imidazole curing agent, which is important for the high temperature stability. Furthermore, ACF using cationic initiator maintained a stable contact resistance in reliability test, although it was cured at low temperature and fast rate. With these results, it was confirmed that the curing method of epoxy had great effect on thermo-mechanical properties and reliability of ACF.