• 한국표면공학회지
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• 제30권2호
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• pp.136-143
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• 1997

The photvoltaic power system has received considerable attention as the petroleumalterative energies to the environmental problems in the wored scale. $CuLnSe_2$is one ofthe most promising materials for the fabrication of large-area modules and low cost photovoltaic devices. Sulfur solute CuInSe2 thin films were prepared by RF sputtering using powder targer which were previously compacted by powder of $Cu_2Se, \;In_2Se_3, \;Cu_2S, \;and\;In_2S_3$ in various ratios. The results induicated that the sulfur ratio, the(112) texture, and the energy band gap were increased by the increase of the S/(S+Se) that was controlled by stoichiometric compound. The energy band gap can be shifted from 1.04eV to 1.50eV by abjusting the S/(S+Se) ratio, which maich it possible to obtain perfect match to the solar spectrum.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.140-143
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• 2004

The west coast of the Korean Peninsula is famous for its large tidal range (up to 9 m) and vast tidal flats. With comparison the sedimentary environments of open and close tidal flat using remote sensing, we select Kanghwa tidal flat and Hwang-Do tidal flat in Cheonsu Bay. Prior to surface sediment discrimination using remote sensing, sedimentary environments including intertidal OEM, hydraulic condition, and relationship between grain size and various tidal condition are investigated. Remote sensing has the potential to provide synoptic information of intertidal environments. The objectives of this study are: (i) to generate an intertidal digital elevation model (OEM) using the waterline method of Lansat TM/ETM+, (ii) to investigate the tidal channel distribution using texture analysis, and (iii) to analyze the relationship between surface grain size by using in-situ data and intertidal OEM and tidal channel density by using high-resolution satellite data such as IKONOS and Kompsat EOC. The results demonstrate that satellite remote sensing is an efficient and effective tool for a surface sediment discrimination and long term morphologic change estimation in tidal flats.

• Journal of Periodontal and Implant Science
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• 제23권2호
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• pp.219-227
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• 1993

The purpose of the present study was to evaluate the effects of 5% tetracycline(Tc) with or without citric acid on periodontally diseased root surfaces. Six single-rooted teeth extracted from one patient was selected and received thorough scaling and root planning, followed by saline irrigation. Each one tooth was divided into eight fragments with a thin separating disc. Total 48 fragments were prepared and setted into 4 groups for this study. Group I (control group)were treated with saline. Group II were treated with 5% Tc gel. Group III were treated with 33% citric acid-5% Tc gel. Group IV were treated with Tc solution. All the specimens are evaluated under Scanning Electron Microscope(SEM). Group I showed large amount of debris in spite of thorough scaling and root planing, but Group II, III & IV showed clean and soft root surface texture. In higher magnification(x3, 000), Group II, III & IV showed nunmerous dentinal tubules, especially Group IV showed collagen fibrils. In the present study, Tc gel and Tc gel with citric showed clinically successful result when treated on periodontally diseased root surface, in vitro.

• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.1-5
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• 2011

[ $CeO_2$ ]has been widely used for single buffer layer of coated conductor because of superior chemical and structural compatibility with $ReBa_2Cu_3O_{7-{\delta}}$(Re=Y, Nd, Sm, Gd, Dy, Ho, etc.). But, the surface of $CeO_2$ layer showed cracks because of the large difference in thermal expansion coefficient between metal substrate and deposited $CeO_2$ layer, when thickness of $CeO_2$ layer exceeds 100 nm on the biaxially textured Ni-3%W substrate. The deposition rate has been limited to be less than 6 $\AA$/sec in order to get a good epitaxy. In this research, we deposited $CeO_2$ single buffer layers on biaxially textured Ni-3%W substrate with 2-step process such as thin nucleation layer(>10 nm) with low deposition rate(3 $\AA$/sec) and thick homo epitaxial layer(>240 nm) with high deposition rate(30 $\AA$/sec). Effect of deposition temperature on degree of texture development was tested. Thick homo epitaxial $CeO_2$ layer with good texture without crack was obtained at $600^{\circ}C$, which has ${\Delta}{\phi}$ value of $6.2^{\circ}$, ${\Delta}{\omega}$ value of $4.3^{\circ}$ and average surface roughness(Ra) of 7.2 nm within $10{\mu}m{\times}10{\mu}m$ area. This result shows the possibility of preparing advanced Ni substrate with simplified architecture of single $CeO_2$ layer for low cost coated conductor.

• 한국재료학회지
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• 제23권7호
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• pp.392-398
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• 2013

A two-pass differential speed rolling(DSR) was applied to a deoxidized low-phosphorous copper alloy sheet in order to form a homogeneous microstructure. Copper alloy with a thickness of 3 mm was rolled to 75 % reduction by two-pass rolling at $150^{\circ}C$ without lubrication at a differential speed ratio of 2.0:1. In order to introduce uniform shear strain into the copper alloy sheet, the second rolling was performed after turning the sample by $180^{\circ}$ on the transverse direction axis. Conventional rolling(CR), in which the rotating speeds of the upper roll and lower roll are identical to each other, was also performed by two-pass rolling under a total rolling reduction of 75 %, for comparison. The shear strain introduced by the conventional rolling showed positive values at positions of the upper roll side and negative values at positions of the lower roll side. However, samples processed by the DSR showed zero or positive values at all positions. {100}//ND texture was primarily developed near the surface and center of thickness for the CR, while {110}//ND texture was primarily developed for the DSR. The difference in misorientation distribution of grain boundary between the upper roll side surface and center regions was very small in the CR, while it was large in the DSR. The grain size was smallest in the upper roll side region for both the CR and the DSR. The hardness showed homogeneous distribution in the thickness direction in both CR and DSR. The average hardness was larger in CR than in DSR.

• 복식문화연구
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• 제29권2호
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• pp.272-288
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• 2021

The purpose of this study is to classify the types of decoration techniques used in women's Chima and Jeogori in traditional Hanbok catalogs from 2010 to 2020, and to analyze the frequency of each type. The method of this study is as follows. This study first investigated the transition of modern Hanbok and decorative techniques by analyzing and classifying such work in previous studies. Based on this, the technique of decorating the Jeogori and Chima that appeared in the traditional Hanbok catalog of the study period was analyzed. The results of the study are as follows. In the case of Jeogori, in the first half of 2010, the decorative technique of a relatively large size was used, and the decorativeness tended to be strong. However, in the late 2010s, the number of decorative techniques used in Jeogori has decreased, and the size of the decorative technique has become smaller and more concise, leading to a tendency to understated decoration. In the case of Chima, techniques to express natural texture by processing threads or fabrics themselves were mainly used rather than techniques to add decoration to the surface, and techniques to express various surface texture tended to develop toward the late 2010s. The change in the decoration technique of Jeogori and Chima appears to be a combination of social, cultural, and economic factors such as a change in consumption culture and a reduction in the wedding market.

• 한국표면공학회지
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• 제56권3호
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• pp.192-200
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• 2023

Graphene, a two-dimensional material, has shown great potential in a variety of applications including microelectronics, optoelectronics, and graphene-based batteries due to its excellent electronic conductivity. However, the production of large-area, high-quality graphene remains a challenge. In this study, we investigated graphene growth on electrolytic copper foil using thermochemical vapor deposition (TCVD) to achieve a similar level of quality to the cold-rolled copper substrate at a lower cost. The combined effects of pre-annealing time, graphenized temperature, and partial pressure of hydrogen on graphene coverage and domain size were analyzed and correlated with the roughness and crystallographic texture of the copper substrate. Our results show that controlling the crystallographic texture of copper substrates through annealing is an effective way to improve graphene growth properties, which will potentially lead to more efficient and cost-effective graphene production. At a hydrogen partial pressure that is disadvantageous in graphene growth, electrolytic copper had an average size of 8.039 ㎛², whereas rolled copper had a size of 19.092 ㎛², which was a large difference of 42.1% compared to rolled copper. However, at the proper hydrogen partial pressure, electrolytic copper had an average size of 30.279 ㎛² and rolled copper had a size of 32.378 ㎛², showing a much smaller difference of 93.5% than before. This observation suggests this potentially leads the way for more efficient and cost-effective graphene production.

• 소성∙가공
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• 제21권2호
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• pp.126-130
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• 2012

Accurate optical texturing of light guide plate over the entire surface area is an important technical issue in LCD TV industry. Injection molding process has the potential to produce large light guide plates having highly efficient optical textures such as micro-prism array. This study is focused on the effect of the degree of replication of the micro texture of the 40" injection molded light guide plates on the overall optical performance of the display panel. Measured replication ratios of the micro-textures formed with three different types of injection molding process were considered in the modeling of prismatic micro segment array. Optical simulation was conducted and results were discussed.

• 한국농공학회지
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• 제14권2호
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• pp.2593-2602
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• 1972

Plastic pipes Wrapped with synthetic filter are recently used for drainage or Collecting of Underground water. But it's use is possible only for small size of diameter less than 300mm, because large size plastic pipes are not readily availabe. For large diameter infiltration gallery, porous concrete pipes are now used, but it's heavy weight brings difficulties in making, moving and setting of the pipes. With it's conventional method of filter setting, fine sands are brought into the pipes to make trouble to lifting pumps and channels Therefore, initial construction cost and maintenance cost become high. To solve-this problem, new method is developed and tested. Small PVC pipes(diameter 14mm) are assembled at the site of construction to newly devised I beam type circls. The size of circular inpiltration gallery is optionally determined by I beam type circle which support small PVC pipes and is made of PVC amterial. This gallery are wrappd with syntheitc filter to prevent sand instruction. In this test, the diameter of 300, 400, 500mm were used. I beam type circles were made with PVC plated with thickness. t=6, 9, 12mm. Water quantity collected through the PVC circulor gallery are measured and the strengths of the gallery. 1. Allowable setting depth of gallery pipe below graund for the case of t=6mm, D=500mm is 2.72m. 2. Collected water quantity depends on soil texture, depth of water grandient of water surface, filter material angle of setting etc. 3. About 126% of water quantity collected from the one gallery pipe measured in two gallery pipes of two parallel installation.

• 한국도로학회논문집
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• 제6권4호
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• pp.123-136
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• 2004

본 연구는 다양한 표면처리 공법에 따른 소음도를 비교 분석하여 소음 감소효과에 적합한 타이닝 방법을 제안하였다. 기존 문헌조사 결과 종방향 타이닝이 소음감소 효과에 우수한 결과를 보인다는 것을 바탕으로 국내 시험도로 일부구간에 표면처리 방법을 적용하였다. 승용차의 경우 일정간격 18mm 종방향 타이닝이 다른 비교구간보다 약 2$\sim$3dB(A) 소음 감소효과가 있다. 덤프트럭으로 외부소음을 측정하여 주파수 분석한 결과 200$\sim$600Hz 사이에서 peak frequency point가 발생하는 것을 알 수 있었다 또한, 승용차의 경우 1000Hz부근에서 소음 발생이 가장 큰 것으로 나타났다 차량 내부 소음 측정결과 표면처리 방법에 따라 소음 정도가 큰 폭으로 변화하지 않았으나, 차량 외부에서는 크게 변화하였다. 따라서 표면처리 방법은 소음도에 중요한 영향을 미치는 인자로 볼 수 있다. 표면처리에 따른 미끄럼 저항값 측정결과 종방향 타이닝이 횡방향 타이닝에 비해 낮게 나타났지만 전체적으로 양호한 결과를 보였다. 본 실험 결과는 시공 초기의 값이므로 공용 이후의 지속적인 조사가 필요하다.