• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3778-3787
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• 2022

The stress-assisted oxidation behaviour of Inconel 52 M/316 austenitic stainless-steel (SS) dissimilar weld joints (DMWJ) in a simulated pressurised water reactor environment was investigated. A corrosion galvanic couple formed between the Inconel 52 M and 316 SS due to differences in their nonferrous metal content. The electric field from the corrosion couple attracted metal cations (e.g. Fe²⁺, Cr³⁺) to the Inconel 52 M that were deposited as FeCr₂O₄. An additional corrosion galvanic couple was generated due to variations in the plastic deformation of the DMWJ. The superposition of electric fields from the different couples resulted in ridge-like oxide depositions in the fusion zone.

• 전기화학회지
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• 제16권1호
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• pp.52-58
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• 2013

고분자 전해질 연료전지(Polymer Electrolyte Membrane Fuel Cell, PEMFC) 상용화를 위해 해결해야 할 과제 중의 하나인 가격 저감을 이루기 위한 방법으로 백금 촉매를 대신할 비귀금속(non-precious metal) 촉매 제조에 관한 연구를 수행하였다. 비귀금속 촉매의 합성은 산소환원반응(oxygen reduction reaction, ORR)의 활성점으로 알려져 있는 코발트-질소(Co-N) 결합을 형성하기 위해 질소를 포함하는 폴리아닐린(PANI)과 코발트염(Co precursor), 그리고 카본 블랙(C)을 일정한 비율대로 혼합한 후 특별한 열처리 과정 없이 단순한 화학적 환원법에 제조되었다. 제조된 Co-PANI-C 복합 촉매의 구조 분석을 위해 X-선 회절분석(X-ray diffraction, XRD)과 열중량분석(thermogravimetric analysis, TGA)을 실시하였고, ORR에 대한 활성을 평가하기 위해 rotating disk electrode(RDE) 및 rotating ring disk electrode(RRDE) 측정을 수행하였다. 그 결과 Co-PANI-C 복합 촉매는 ORR반응에 대한 개시 전압은 백금 촉매보다 60 mV 밖에 낮지 않은 값을 보였지만, 반응에 의해 발생되는 환원 전류는 여전히 백금 촉매보다 낮은 값을 보였다. 이 밖에도 전극 회전 속도에 따른 ORR 특성 변화, 전압 사이클 회수에 따른 내구성 변화, 연료전지 적용 시 성능 변화에 대해 논의할 것이다.

• 보존과학회지
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• 제32권2호
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• pp.189-202
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• 2016

서산 지역 야철지에서 수습한 슬래그와 원광석의 재료적 특징을 알아보기 위해 금속현미경, SEM으로 미세조직을 관찰하였으며, XRF, EDS 분석을 이용한 성분분석을 실시하였다. XRD 분석을 통해 광물성분을 동정하였고 납 동위원 소비 분석을 이용하여 원료의 산지를 추정하였다. 성분분석 결과 PbO, ZnO 등의 함량이 높게 검출되어 철 보다는 비철금속을 제련하는 과정에서 생성된 슬래그임을 알 수 있었다. 또한 슬래그의 주요조직은 Fayalite, Galena, Magnetite이며, 원광석은 Galena, Anglesite, Pyrite 등의 광물로 동정되었다. 납 동위원소비 분석 결과, 대부분 한반도 서부 경기지괴에 해당하며, 특히 원광석과 슬래그 중 3점은 한국 서부 경기지괴 중 시료가 수습된 위치인 서산 도성리가 산지로 추정되었다. 즉 이번에 분석한 슬래그는 제철 제련 과정이 아닌 비철금속을 제련할 때 생성된 것이며, 특히 서산 도성리에서 채굴한 원광석을 이용하여 비철금속을 제련했을 가능성이 높다. 향후 이 지역의 다양한 슬래그들을 분석하면 고대로부터 이루어졌던 철 제련뿐만 아니라 비철의 제련과정을 이해하는데 큰 도움이 될 것으로 보인다.

• 한국CDE학회논문집
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• 제5권3호
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• pp.242-254
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• 2000

This paper describes an efficient solid modeling method for thin-walled plastic or sheet metal parts, based on the non-manifold offsetting operations. Since the previous methods for modeling and converting a sheet into a solid have adopted the boundary representations for solid object as their topological framework, it is difficult to represent the exact adjacency relationship between topological entities of a sheet model and a mixture of wireframe and sheet models that can appear in the meantime of modeling procedure, and it is hard to implement topological operations for sheet modeling and transformation of a sheet into a solid. To solve these problems, we introduce a non-manifold B-rep and propose a sheet conversion method based on a non-manifold offset algorithm. Because the non-manifold offset aigorithm based on mathematical definitions results in an offset solid with tubular and spherical thickness-faces we modify it to generate the ruled or planar thickness-faces that are mostly shown in actual plastic or sheet metal parts. In addition, in order to accelerate the Boolean operations used the offset algorithm, we also develope an efficient face-face intersection algorithm using topological adjacency information.

• 한국토양비료학회지
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• 제49권5호
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• pp.627-634
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• 2016

The objectives of this study were to select optimal soil amendments through analysis of heavy metal availability in soil and uptake to Aster koraiensis Nakai for forest rehabilitation of heavy metal contaminated soil of abandoned metal mine. A. koraiensis was cultivated for 6 months at contaminated soil with several soil treatments (bottom ash 1 and 2%, fly ash 1 and 2%, waste lime+oyster 1 and 2%, Acid mine drainage sludge (AMDS) 10 and 20%, compost 3.4%, non-contaminated natural forest soil, and control). The analysis results of heavy metal concentrations in the soil by Mehlich-3 mehthod, growth and heavy metal concentrations of A. koraiensis showed that waste oyster+lime 1% and compost were more effective than the other amendments for phytostabilization. However, it is needed comprehensive review of factors such as on-site condition, slope covering to reduce soil erosion and vegetation introduction from surround forest for revegetation to apply forest rehabilitation.

• 한국콘텐츠학회논문지
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• 제15권6호
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• pp.168-178
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• 2015

본 연구는 츠카모토 신야의 영화 <철남>(1989)의 기계적-몸 이미지에 대한 연구로 탈인간화 하는 몸 그리고 욕망에 대한 해석을 시도 하였다. <철남>에서 살펴본 기계적-몸 이미지는 초현실주의적 이미지, 그로테스크적 이미지, 그리고 에로스적 이미지로 관찰되었다. 기계적-몸의 초현실주의적 이미지는 <철남>의 변화과정에서 보이는 변용, 파괴, 착란, 그리고 환상에 대한 과장으로 파악되었고, 그로테스크적 이미지는 인물의 일상적인 공간에서 기괴한 형태로의 변형으로 인간의 내재된 실체를 보여줌으로써 엽기성과 나약함이 혼합된 이미지로 관찰 되었다. 그리고 에로스적 이미지는 불완전한 존재가 완전함을 추구하고자 하는 욕망에 의해 스스로의 파괴와 재탄생을 이루는 과정에서 나타났다. 위의 세 가지 이미지 유형에 대한 분석은 세계정복을 꿈꾸는 과부화된 인간의 욕망이 탈인간화된 기계적-몸으로서 비유기체로의 시각화로 귀결된다.

• 한국환경과학회지
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• 제24권8호
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• pp.969-980
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• 2015

In order to certificate the distribution and pollution of heavy metal of surface sediments in Nakdong River were collected and analyzed for grain size, water content, ignition loss and heavy metal content. Surface sediments mainly composed of sand(avg. 94.6%) and water content and ignition loss were 20.46%, 1.53% on average. Grain size were relatively fine and organic matter content were relatively high in the Hoichun and Sunakdonggang. Most of heavy metal content(Zn > Cr > Pb > Ni > Cu > Hg) in the Deokcheongang and Sunakdonggang were higher than the other streams. The Igeo were non polluted(less than 0) in all streams and the EF were relatively high in the small stream and PLI were non polluted(less than 1). In addition, organic matter, heavy metal content and pollution were highly correlation with grain size. Surface sediments in study area, heavy metal pollution of the Sunakdonggang were relatively high compared to the other stream but these results were not serious pollution that exceed the sediment pollution evaluation standard of river and lake in Korea and pollution levels adversely affected the majority of benthos were not.

• 한국토양비료학회지
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• 제47권4호
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• pp.290-298
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• 2014

A bacterial strain with the potential ability to solubilize heavy metals was isolated from heavy metal contaminated soils collected from abandoned mines of Boryeong area in South Korea. The bacterial strain with the highest degree of metal resistance was shown to have close proximity with Shewanella xiamenensis FJ589031, according to 16S rRNA sequence analysis, and selected for investigating the mobilization of metals in soil or plant by the strain. The strain was found to be capable of solubilizing metals both in the absence and in the presence of metals (Co, Pb and Cd). Metal mobilization potential of the strain was assessed in a batch experiment and the results showed that inoculation could increase the concentrations of water soluble Co, Pb and Cd by 48, 34 and 20% respectively, compared with those of non-inoculated soils. Bacterial-assisted growth promotion and metal uptake in sunflower (Helianthus annuus) was evaluated in a pot experiment. In comparison with non-inoculated seedlings, the inoculation led to increase the growth of H. annuus by 24, 18 and 16% respectively in Co, Pb and Cd contaminated soils. Moreover, enhanced accumulation of Co, Pb and Cd in the shoot and root systems was observed in inoculated plants, where metal translocation from root to the above-ground tissues was also found to be enhanced by the strain. Plant growth promotion and metal mobilizing potential of the strain suggest that the strain could effectively be employed in enhancing phytoextraction of Co, Pb and Cd from contaminated soils.

• 한국재료학회지
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• 제19권7호
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• pp.349-355
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• 2009

Metal thin film patterns on a LTCC substrate, which was connected through inner via and metal paste for electrical signals, were formed by a screen printing process that used electric paste, such as silver and copper, in a conventional method. This method brought about many problems, such as non uniform thickness in printing, large line spaces, and non-clearance. As a result of these problems, it was very difficult to perform fine and high resolution for high frequency signals. In this study, the electric signal patterns were formed with the sputtered metal thin films (Ti, Cu) on an LTCC substrate that was coated with protective oxide layers, such as $TiO_2$ and $SiO_2$. These electric signal patterns' morphology, surface bonding strength, and effect on electro plating were also investigated. After putting a sold ball on the sputtered metal thin films, their adhesion strength on the LTCC substrate was also evaluated. The protective oxide layers were found to play important roles in creating a strong design for electric components and integrating circuit modules in high frequency ranges.

• 한국방사선학회논문지
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• 제16권6호
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• pp.709-718
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• 2022

본 연구의 목적은 토모테라피 방사선치료에서 고밀도 알루미늄, 티타늄, 강철 금속 삽입물에 대한 단층촬영(CT)을 평가하고 자 하였다. 다양한 밀도의 원통형 막대를 포함한 금속 삽입물과 함께 원통형 토모팬텀을 이용하여 영상을 얻었다. 총 세 가지의 CT 영상에 대해 평균 CT 값(number)와 표준 편차를 구하고, 치료계획 선량평가도 수행하였다. 고밀도 금속 삽입물이 CT값과 변화가 가장 컸다. 타겟에 대한 선량평가(적합성 지수, CI)에서 반복적 금속 인공물 감소 알고리즘(iMAR)이 적용된 영상이 그렇지 않은 영상에 비해 약 20% 좋았으나 유의한 차이는 없었다. iMAR은 표적 및 장기의 묘사에 도움을 주고 토모테라피를 이용한 3차원 입체조형 방사선치료기술(3D-CRT)에서 불확실성을 줄이는 데 도움이 될 것으로 사료된다.