• 한국정보통신학회논문지
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• 제18권2호
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• pp.425-430
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• 2014

본 연구에서는 이중게이트 MOSFET의 게이트 산화막 두께 변화에 따른 문턱전압이하 전류의 변화를 분석하였다. 이중게이트 MOSFET의 채널 내 전위분포를 구하기 위하여 포아송방정식을 이용하였으며 이때 전하분포함수에 대하여 가우시안 함수를 사용하였다. 전위분포는 경계조건을 이용하여 채널크기에 따른 해석학적인 함수로 구하였다. 가우시안 함수의 변수인 이온주입범위 및 분포편차 그리고 게이트 산화막 두께 등에 대하여 문턱전압이하 전류 특성의 변화를 관찰하였다. 본 연구의 전위모델에 대한 타당성은 이미 기존에 발표된 논문에서 입증하였으며 본 연구에서는 이 모델을 이용하여 문턱전압이하 전류 특성을 분석하였다. 분석결과, 문턱전압이하 전류는 게이트 산화막 두께 및 가우시안 분포함수의 변수 등에 크게 영향을 받는 것을 관찰할 수 있었다.

• 한국세라믹학회지
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• 제51권1호
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• pp.11-18
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• 2014

Onggi, which is described as a breathing pottery, has strongly influenced the traditional food culture in Korea. In this study Onggi is compared to porcelains including celadon and white porcelain to analyze the sources of pore formation. The differences in starting materials are examined for chemical and mineralogical compositions, particle size and distribution. The gas permeability of the fired samples is correlated to the matrix microstructure. The broad particle size distribution and high iron oxide content of Onggi are revealed as the major cause for the pore formation. Open pores are formed with large particles in the Onggi body while closed pores have a high iron oxide concentration. The Onggi body with increased open pores leads to the high gas permeability.

• 한국정보통신학회논문지
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• 제18권12호
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• pp.2939-2945
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• 2014

본 연구에서는 대칭 및 비대칭 산화막 구조를 가진 이중게이트(double gate; DG) MOSFET의 문턱전압 변화에 대하여 분석하였다. 상하단 동일한 산화막 두께을 갖는 대칭 DGMOSFET와 달리 비대칭 DGMOSFET는 상하단 게이트 산화막 두께를 다르게 제작할 수 있다. 그러므로 비대칭 DGMOSFET에서 상단과 하단게이트 산화막 두께의 크기 변화에 따라 대칭 DGMOSFET와 문턱전압을 비교하여 상하단 게이트 산화막 두께의 최적값에 대하여 고찰하고자 한다. 문턱전압을 구하기 위하여 포아송방정식에서 해석학적 전위분포모델을 유도하였으며 도핑분포함수는 가우스분포함수를 사용하였다. 문턱전압 모델을 이용하여 하단게이트 전압, 채널길이 및 채널두께 등에 따라 상하단게이트 산화막 두께가 문턱전압에 미치는 영향을 관찰하였다. 결과적으로 문턱전압은 상하단 게이트 산화막 두께에 따라 크게 변화하였으며 변화하는 경향은 하단게이트 전압, 채널길이 그리고 채널두께에 따라 매우 상이하게 나타나고 있다는 것을 알 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.755-758
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• 2014

본 연구에서는 대칭 및 비대칭 산화막 구조를 가진 이중게이트(double gate; DG) MOSFET의 문턱전압 변화에 대하여 분석하였다. 상하단 동일한 산화막 두께을 갖는 대칭 DGMOSFET와 달리 비대칭 DGMOSFET는 상하단 게이트 산화막 두께를 다르게 제작할 수 있다. 그러므로 비대칭 DGMOSFET에서 상단과 하단게이트 산화막 두께의 크기 변화에 따라 대칭 DGMOSFET와 문턱전압을 비교하여 상하단 게이트 산화막 두께의 최적값에 대하여 고찰하고자 한다. 문턱전압을 구하기 위하여 포아송방정식에서 해석학적 전위분포모델을 유도하였으며 도핑분포함수는 가우스분포함수를 사용하였다. 문턱전압 모델을 이용하여 하단게이트 전압, 채널길이 및 채널두께 등에 따라 상하단게이트 산화막 두께가 문턱전압에 미치는 영향을 관찰하였다. 결과적으로 문턱전압은 상하단 게이트 산화막 두께에 따라 크게 변화하였으며 변화하는 경향은 하단게이트 전압, 채널길이 그리고 채널 두께에 따라 매우 상이하게 나타나고 있다는 것을 알 수 있었다.

• 한국표면공학회지
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• 제47권4호
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• pp.155-161
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• 2014

The present work is concerned with the formation behavior of anodic oxide films on Al7075 alloy under a galvanostatic condition in 20 vol.% sulfuric acid solution. The formation behaviour of anodic oxide films was studied by the analyses of voltage-time curves and observations of colors, morphologies and thicknesses of anodic films with anodization time. Hardness of the anodic oxide films was also measured with anodization time and at different positions in the anodic films. Six different stages were observed with anodiziation time : barrier layer formation (stage I), pore formation (stage II), growth of porous films (stage III), abnormal rapid oxide growth (stage IV), growth of non-uniform oxide films (stage V) and breakdown of the thick oxide films under high anodic voltages (stage VI). Hardness of the anodic oxide films appeared to decrease with increasing anodization time and with the position towards the outer surface. This work provides useful information about the thickness, uniformity, imperfections and hardness distribution of the anodic oxide films formed on Al7075 alloy in sulfuric acid solution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.67-70
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• 1996

In this paper, the three-dimensional stress effect of thermal oxide is simulated. We developed the three-dimensional finite element numerical simulator including three-dimensional adaptive mesh generator that is able to refine and eliminate nearby moving boundary of oxide, and oxidation solver with stress model. The main effect of deformation at the coner area of oxide is due to distribution of oxidant, but the deformation of oxide is affected by the stress in the oxide. In the island structure which is the structure mostly covered with nitride and a coner is opened to oxidation, oxidation is reduced at the coner by compressive stress. In the hole structure which is the structure mostly opened to oxide and a coner is covered with nitride, however, oxidation is increased at the coner by tensile stress.

• 대한방사성의약품학회지
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• 제7권2호
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• pp.133-140
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• 2021

Various iron oxide nanoparticle-based radiomaterials(IO-NRM) can be used for multimodal imaging of magnetic resonance imaging and molecular imaging, can be easily sized, can be easily functionalized, and have biocompatibility, making them a very good platform for molecular imaging. Based on the previously revealed molecular imaging technology of iron oxide nanoparticles, this paper introduces the in vivo distribution and use in various diseases through iron oxide nanoparticles-based radiolabeled compounds for diagnosis and treatment of iron oxide nanoparticles-based molecular imaging platforms. We would like to look forward to its potential as a radiopharmaceutical.

• 대한기계학회논문집B
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• 제29권10호
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• pp.1148-1155
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• 2005

In this study, the influence of changing combustor pressure on nitric oxide emission was investigated. Expansion of reaction region was more clear in the P$^{*}$ <1 conditions compared to the P$^{*}\geq1$ conditions, and it could be observed that flames are distinct in the P$^{*}\geq1$ conditions and that brightness is relative low and wide distribution is shown in the P$^{*}$ <1 conditions. In the respect of temperature distribution, narrow and high-temperature region was shown in the P$^{*}\geq1$ conditions. On the other hands, overall uniform temperature distributions were shown in the P$^{*}$ <1 conditions. Nitric oxide emission decreased with decreasing combustor pressure. This tendency was explained by the mean flame temperature distribution. Low NOx combustion is ascribed to wide-spread reaction region in the low combustor Pressure and oscillation were shown P$^{*}\leq0.97$, and strength and sizes of oscillation were more increased with lower pressure index. These results demonstrate that flame shape and nitric oxide emission can be controlled with changing combustor pressure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2329-2331
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• 1999

Metal oxide surge arrester were developed in the late 1970s, and were immediately adopted as significant breakthrough in over voltage protection of power system. Work was continued throughout the world on the design, development and application of metal oxide surge arrester. This paper describes the evaluating test and results of practical use for analyzing the performance of gapless metal oxide surge arresters under various type test.

• Nuclear Engineering and Technology
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• 제46권6호
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• pp.857-862
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• 2014

Mechanical alloying under various gas atmospheres such as Ar, an Ar-$H_2$ mixture, and He gases were carried out, and its effects on the powder properties, microstructure and mechanical properties of ODS ferritic steels were investigated. Hot isostatic pressing and hot rolling processes were employed to consolidate the ODS steel plates. While the mechanical alloyed powder in He had a high oxygen concentration, a milling in Ar showed fine particle diameters with comparably low oxygen concentration. The microstructural observation revealed that low oxygen concentration contributed to the formation of fine grains and homogeneous oxide particle distribution by the Y-Ti-O complex oxides. A milling in Ar was sufficient to lower the oxygen concentration, and this led a high tensile strength and fracture elongation at a high temperature. It is concluded that the mechanical alloying atmosphere affects oxygen concentration as well as powder particle properties. This leads to a homogeneous grain and oxide particle distribution with excellent creep strength at high temperature.