• 한국전기전자재료학회논문지
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• 제22권12호
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• pp.1005-1008
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• 2009

In this study, adaptively coupled plasma (ACP) source was used for dry etching of $Al_2O_3$ thin film. During the etching process, the wafer surface temperature is an important parameter to influent the etching characteristics. Therefore, the experiments were carried out in ACP to measuring the etch rate, the selectivities of $Al_2O_3$ thin film to mask materials and the etch profile as functions of $Cl_2$/Ar gas ratio and substrate temperature. The highest etch rate of $Al_2O_3$ was 65.4 nm/min at 75% of $Cl_2/(Cl_2+Ar)$ gas mixing ratio. The etched profile was characterized using field effect scanning electron microscopy (FE-SEM). The chemical states of $Al_2O_3$ thin film surfaces were investigated with x-ray photoelectron spectroscopy (XPS).

• Tribology and Lubricants
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• 제38권6호
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• pp.281-286
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• 2022

In this study, the effects of Elasto-hydrodynamic lubrication pressure on the critical shoulder height of raceway in an angular contact ball bearing were investigated. Both 3D contact analyses using an influence function and the EHL analysis were conducted for the contact geometry between the ball and raceways. The pressure distributions by 3D contact analysis and EHL analysis for an example bearing were compared. The effect of ellipse truncation on the minimum film thickness also investigated from EHL analysis. The critical shoulder height in the dry contact and the EHL state were compared for various applied loads. It is shown that when the ellipse truncation occurs, the pressure spike for the EHL conjunction is higher than that for the dry contact, and its location moves more inward of the contact center. The steep pressure gradients would increase the flow rate, so in order to maintain flow continuity a significant reduction in film thickness and an abrupt rise in pressure occurs in the edge of shoulder. Significant reduction of the minimum film thickness occurs near the edge of shoulder. The critical shoulder heights in the EHL state are calculated as higher values compared with in the dry contact. This results shows that the determination of critical shoulder height by the EHL analysis is more proper.

• 전기학회논문지
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• 제56권6호
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• pp.1080-1086
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• 2007

The aim of this paper is to establish the optimum fabrication condition of specimens, using the Vapor Deposition Polymerization Method(VDPM), which is one of modesto prepare functional organic thin films using a dry process, and to develop a thin film type humidity sensor which has good humidity sensitive characteristics. The inner part of the film became denser and roughness of the film surface eased as curing temperature increased so that thickness of the film could be made uniform. This also shows the appropriate curing temperature was $250^{\circ}C$. The basic structure of the humidity sensor is a parallel capacitor which consists of three layers of Aluminum/Polyimide/Aluminum. The result of SEM and AFM measurement shows that the thickness of PI thin films decreased and the refraction increased as curing temperature increased, which indicates that a capacitance-type humidity sensor utilizing polyimide thin film is fabricated on a glass substrate. The characteristics of fabricated samples were measured under various conditions, and the samples had linear characteristics in the range of 20-80 %RH, independent of temperature change, and low hysteresis characteristic.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.57-65
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• 2016

By high speed Liquid Droplet Impingement (LDI) on material, fluid systems are seriously damaged, therefore, it is important for the solution of the erosion problem of fluid systems to consider the effect of material in LDI. In this study, by using an in-house fluid/material two-way coupled method which considers reflection and transmission of pressure, stress and velocity on the fluid/material interface, high-speed LDI on wet/dry material surface is simulated. As a result, in the case of LDI on wet surface, maximum equivalent stress are less than those of dry surface due to damping effect of liquid film. Empirical formula of the damping effect function is formulated with the fluid factors of LDI, which are impingement velocity, droplet diameter and thickness of liquid film on material surface.

• 한국표면공학회지
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• 제42권4호
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• pp.169-172
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• 2009

We investigated the dry-etching mechanism of the TiN thin film using a $Cl_2$/Ar inductively coupled plasma system. To understand the effect of the $Cl_2$/Ar gas mixing ratio, we etched the TiN thin film by varying $Cl_2$/Ar gas mixing ratio. When the gas mixing ratio was 100% $Cl_2$, the highest etch rate was obtained. The chemical reaction on the surface was investigated with X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) was used to examine etched profiles of the TiN thin film.

• 한국안광학회지
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• 제21권1호
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• pp.11-21
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• 2016

목적: 본 연구에서는 동일재질의 투명 및 써클소프트콘택트렌즈(써클렌즈)를 정상안과 건성안에 착용시켰을 때 착용시간 경과에 따른 눈물막 안정성의 차이를 분석하고자 하였다. 방법: 연구대상자를 눈물량에 따라 정상안과 건성안으로 분류한 후 hilafilcon B 재질과 nelfilcon A 재질의 투명 및 써클렌즈를 각각 착용시키고, 렌즈 착용 30분 후, 6시간 후에 비침입성 눈물막 파괴시간, 렌즈중심안정위치, 눈물막깨짐 시작부위를 측정하여 눈물막 안정성의 변화를 알아보였다. 결과: 정상안과 건성안 모두 투명 및 써클콘택트렌즈 착용 시 착용시간경과에 따라 눈물막파괴시간은 통계적으로 유의한 감소를 보였다. 눈물막깨짐 시작 비율은 두 렌즈 모두 투명렌즈보다 써클렌즈의 주변부에서 높았고, 정상안보다는 건성안의 주변부에서 높게 나타났다. Hilafilcon B 재질보다는 nelfilcon A 재질 렌즈의 주변부에서 눈물막깨짐 시작 비율이 높았으나 착용시간경과에 따른 변화는 서로 다른 양상으로 나타났다. 한편, hilafilcon B 재질의 써클렌즈 착용 시 단위면적 당 눈물막깨짐 개수는 모두 주변부에서 많게 나타났던 반면, nelfilcon A 재질 써클렌즈의 경우는 착용시간 경과에 따라 중심부에서의 수가 증가하였다. 또한, 렌즈중심안정위치는 착용시간 경과에 따라 두 재질 모두 써클렌즈에 비해 투명렌즈가 동공중심 가까이에 존재하였으나 정상안에 비해 건성안의 중심이탈이 크게 나타났다. 결론: 본 연구결과 렌즈착용시간이 경과함에 따라 착색공정을 거친 써클렌즈 뿐만 아니라 투명렌즈도 눈물막에 미치는 영향이 달라질 수 있으며, 렌즈재질에 따라 눈물막 안정성에 영향을 주는 요인 또한 달라짐을 알 수 있었다. 따라서 투명 및 써클렌즈를 착용하고자 할 때에는 착용자의 일일착용시간이나 착용기간 등과 같은 사용습관에 따라 렌즈의 착색공법/염료 뿐만 아니라 렌즈 재질 또한 고려하여 적절한 렌즈를 선택하여야 할 것이다.

• 현장농수산연구지
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• 제23권1호
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• pp.49-57
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• 2021

생분해성 필름에 종자를 부착하여 논 표면에 펴는 멀칭 건답 및 습답 점파기술은 2015년 주요 곡물·조사료자급률제고사업단, 농촌진흥청 등에서 현장 실증시험을 실시하였다. 그러나 파종 후 관개하였을 때 필름이 뜨는 문제점으로 입모 불안정, 종자 부착에 따른 비용 및 불편 등 문제가 많았지만, 필름이 뜨지 않게 초기 물관리 등을 잘한 포장에서는 기존 건답직파, 무논점파 등과 수량이 거의 같거나 높은 것으로 나타나 이러한 문제점을 보완하면 가능성이 있는 기술로 판단되었다. 2016년 멀칭필름에 종자를 부착하는 방법과 다른 필름을 피복하면서 종자를 점파하는 방법으로 한국농수산대학에서 창안하여 국내 비닐멀칭 농업기계 생산 전문업체와 산학공동연구하여 제작한 멀칭건답점파 시작기에 생분해 필름 원료 공급 및 성형 전문업체와 협업으로 실증시험을 실시한 결과 멀칭 건답점파기는 필름절단장치, 작업선긋기 장치, 안전장치 등을 보완하여 실용화의 가능성이 인정되어 개발을 완료하였다. 하지만 시험에 사용한 생분해 필름은 두께, 성분조성, 물리성 등이 약한 것으로 사료되었으며 특히 담수환경 논 조건에서 빠른 분해로 발생된 잡초가 필름을 뚫고 올라와 7월 하순 잡초 발생이 심하여 문제점으로 나타나 이에 대한 후속 연구가 요구되었다.

• 한국재료학회지
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• 제14권1호
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• pp.46-51
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• 2004

The annealing of a Cu(4.5at.% Mg)/$SiO_2$/Si structure in ambient $O_2$, at 10 mTorr, and $300-500^{\circ}C$, allows for the outdiffusion of the Mg to the Cu surface, forming a thin MgO (15 nm) layer on the surface. The surface MgO layer was patterned, and successfully served as a hard mask, for the subsequent dry etching of the underlying Mg-depleted Cu films using an $O_2$ plasma and hexafluoroacetylacetone [H(hfac)] chemistry. The resultant MgO/Cu structure, with a taper slope of about $30^{\circ}C$ shows the feasibility of the dry etching of Cu(Mg) alloy films using a surface MgO mask scheme. A dry-etched Cu(4.5at.% Mg) gate a-Si:H TFT has a field effect mobility of 0.86 $\textrm{cm}^2$/Vs, a subthreshold swing of 1.08 V/dec, and a threshold voltage of 5.7 V. A novel process for the dry etching of Cu(Mg) alloy films, which eliminates the use of a hard mask, such as Ti, and results in a reduction in the process steps is reported for the first time in this work.

• 한국의류학회지
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• 제12권2호
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• pp.217-223
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• 1988

This study is to examine the cleaningproof by dry cleaning runs and parts(shoulder, belly, butt) of garment leathers tanned chrome. This study is composed of three methods of test; color difference test, surface view by scanning electron micrographs, mechanical properties measurement by KES-FB system. The results obtained were as follows: 1. In stiffening of parts of sample, the belly is the best degree in smoothness, fullness, softness. But that of the butt have been found to be the worst degree and to be thick. 2. In fading of parts, the shoulder is an extreme case, but the belly is the best among three parts. 3. In dry cleaning runs, the view after 3 runs has been found to be the best result. 4. The stiffening after dry cleaning 1 run have been low grade, for the sample absorb much solvent of dry cleaning. And, the fading and the decoloration are to be worse after 5 runs. Because the leather surface is affected by dry cleaning runs.

• 한국동물생명공학회지
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• 제36권1호
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• pp.59-68
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• 2021

This study was performed to identify the effect of synovium graft on conjunctiva in rabbits after dry eye induction. Six New Zealand White rabbits were used as dry eye models. Both eyes were divided to two groups as control and synovium graft group. The synovium graft was performed in fourth week after dry eye modeling. Quantitative change of tears through Schirmer tear test (STT), qualitative change of tear film through tear film break up time (TFBUT), and damage of cornea through fluorescein staining were observed for 10 weeks at intervals of two weeks. Histological examination was performed to evaluate cornea and conjunctiva at tenth week. In both groups, STT and TFBUT were significantly decreased in 4 weeks after modeling compared to 0 weeks (p < 0.05) . After synovium graft, there were increases in STT value at 4 weeks and TFBUT at 4 and 6 weeks in graft group (p < 0.05). Corneal fluorescein staining showed no significant difference between the two groups. In histopathological examination, grafted synovium was detected as round to ovoid ingression folds, well attached to grafted regions with 0.11 ± 0.04 mm² (range, 0.05-0.16 mm²). These results indicated that the synovium graft on the conjunctiva had an effect on the qualitative and quantitative improvement of the tear film even though there was no histological change.