• 센서학회지
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• 제15권6호
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• pp.386-390
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• 2006

This paper describes the ohmic contact formation of polycrystalline 3C-SiC films deposited on thermally grown Si wafers. In this work, a TiW (titanium tungsten) film as a contact material was deposited by RF magnetron sputter and annealed with the vacuum process. The specific contact resistance (${\rho}_{c}$) of the TiW contact was measured by using the C-TLM (circular transmission line method). The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature as also analyzed by XRD (X-ray diffraction) and SEM (scanning electron microscope). All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30 min., the lowest contact resistivity of $2.90{\times}10{\Omega}cm^{2}$ was obtained due to the improved interfacial adhesion. Therefore, the good ohmic contact of polycrystalline 3C-SiC films using the TiW film is very suitable for high-temperature MEMS applications.

• E2M - 전기 전자와 첨단 소재
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• 제10권1호
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• pp.8-14
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• 1997

The UV/O$_{3}$ dry cleaning has been well known in removing organic molecules. The UV/O$_{3}$ dry cleaning method was performed to clean the Si wafer surfaces and contact holes contaminated by organic molecules such as residual PR. During the cleaning process, the Si surfaces were analyzed with X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and ellipsometer. When the UV/O$_{3}$ dry cleaning at 200'C was performed for 3 minutes, the residual photoresist was almost removed on Si wafer surfaces, but Si surfaces were oxidized. For UV/O$_{3}$ application of contact hole cleaning, the contact string were formed using the equipment of ISRC (Inter-university Semiconductor Research Center). Before Al deposition, UV/O$_{3}$ (at 200.deg. C) dry cleaning was performed for 3 minutes. After metal annealing, the specific contact resistivity was measured. Because UV/O$_{3}$ dry cleaning removed organic contaminants in contact holes, the specific contact resistivity decreased. Each contact hole size was different, but the specific contact resistivities were all much the same. Thus, it is expected that the UV/O$_{3}$ dry cleaning method will be useful method of removal of the organic contaminants at smaller contact hole cleaning.

• 한국안광학회지
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• 제20권4호
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• pp.437-443
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• 2015

목적: 본 연구는 3-chloropyridine-4-carboxylic acid와 3-fluoropyridine-4-carboxylic acid를 첨가제로 사용하여 소프트 콘택트렌즈 제조 후 물리적 및 광학성 특성을 분석하여 콘택트렌즈 재료로서 활용도를 알아보았다. 방법: 본 실험에서는 소프트 하이드로젤 콘택트렌즈의 주재료인 HEMA (2-hydroxyethyl methacrylate)와 AA(acylic acid), MMA(methacrylic acid) 그리고 개시제인 AIBN(azobisisobutyronitrile), 교차결합제인 EGDMA(ethylene glycol dimethacrylate)를 사용하여 공중합 하였다. 결과: 생성된 고분자의 물리적 특성을 측정한 결과, 굴절률 1.4320~1.4342, 함수율 34.54~37.15%, 접촉각 $57.82{\sim}79.57^{\circ}$, 인장강도 0.2872~0.3608로 각각 나타났고 광학적 특성 측정 결과 가시광선 영역에서는 투과율이 88.8~90.6%로 나타났으며, UV-B 76.8~82.4%, UV-A 84.6~86.6%로 각각 나타났다. 결론: 본 실험 결과 3-chloropyridine-4-carboxylic acid 및 3-fluoropyridine-4-carboxylic acid를 첨가제로 사용하였을 때 고습윤성 및 자외선 차단기능을 가진 콘택트렌즈 재료로 활용될 수 있을 것으로 판단된다.

• 한국콘텐츠학회논문지
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• 제21권5호
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• pp.465-476
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• 2021

이 연구는 불법 성콘텐츠 접촉과 불법 성콘텐츠 유통의 그 원인요인들 및 통제요인들을 제시하고 그 요인들 간의 상호작용효과를 각각 살펴보고 비교하였다. 원인요인으로는 낮은 자기통제력, 불법 성콘텐츠 경험 친구, 그리고 가부장가정 요인을, 그리고 통제요인들로는 도덕태도, 공식처벌, 기회제약을 다뤘다. 그리고 세 원인요인들의 영향에 대한 세 통제요인들의 조절 혹은 완충효과를 살펴보았다. 서울시 대학생을 조사대상으로 하는 분석결과 대체로 불법 성콘텐츠 접촉과 불법 성콘텐츠 유통에서 그 원인요인들의 작용은 유사해 낮은 자기통제력, 불법 성콘텐츠 경험 친구, 그리고 가부장가정 모두가 크게 유의미했고 그 중에서도 불법 성콘텐츠 경험 친구와의 접촉의 영향력이 가장 컸다. 불법 성콘텐츠 접촉 및 유통에 대한 원인요인들과 통제요인들의 상호작용효과에 대한 결과를 보면 그 결과가 상이했다. 불법 성콘텐츠 접촉의 경우 원인요인들과 통제요인들과의 상호작용효과가 모두 유의미하지 않았다. 즉 불법 성콘텐츠 접촉에서는 원인요인 모두가 독립적으로만 유의미하게 작동했으며 그 작용을 어떠한 통제요인들도 통제하지 못했다. 그러나 불법 성콘텐츠 유통의 경우는 낮은 자기통제력과 도덕태도간의 상호작용효과, 불법 성콘텐츠 유통 친구와 도덕태도간의 상호작용효과가 유의미했고, 가부장가정과 공식처벌간의, 그리고 가부장가정과 기회제약간의 상호작용효과가 유의미했다. 그 결과의 함의를 논의한다.

• 대한화학회지
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• 제54권1호
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• pp.99-104
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• 2010

HEMA (2-hydroxyethyl methacrylate), NVP (N-vinyl pyrrolidone), MMA (methyl methacrylate)가 담긴 몰드에 백금나노입자를 첨가한 후 농도조건을 다양화 하여 $70^{\circ}C$에서 약 40분, $80^{\circ}C$에서 약 40분, $100^{\circ}C$에서 약 40분 동안의 열처리 공정을 각기 거쳐 공중합 하였다. 제조된 콘택트렌즈의 물리적 특성을 측정한 결과, 산소투과율은 $9{\sim}15{\times}10^{-9}$ cm/s mL $O_2$/mL ${\times}$ mmHg, 함수율은 34.22~35.52%, 굴절률은 1.432~1.435, 가시광선 투과율은 88.3~91.2% 그리고 인장강도 값은 0.141~0.152 Kgf을 나타내었다. 제조된 콘택트렌즈는 여러 가지 색을 띠어 인공착색제를 사용하지 않고서도 콘택트렌즈에 착색효과를 나타내었으며, 콘택트렌즈로 사용 가능한 물리적 특성에 부합되어 안 의료용 기능성 소재로의 응용이 충분히 가능할 것으로 판단된다.

• 대한화학회지
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• 제53권6호
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• pp.749-754
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• 2009

HEMA (2-hydroxyethyl methacrylate)는 친수성 안 의료용 소재로써 폭넓게 사용되고 있으며, 특히 소프트 콘택트렌즈 제조에 가장 많이 사용되는 재료중의 하나이다. 또한 산소투과율(Dk/t)은 콘택트렌즈 재료의 성능을 평가하기 위한 물리적 특성 중 매우 중요한 요소이다. 본 연구는 HEMA (2-hydroxyethyl methacrylate), MMA (methylmethacrylate), NVP (N-vinyl-pyrrolidone), 교차결합제인 EGDMA (ethylene glycol dimethacrylate)를사용하여 공중합 하였으며, 일반 콘택트렌즈와 칼라 콘택트렌즈를 제조하여 중심부와 주변부의 산소투과율을 polarographic method로 측정하였다. 실험 결과 polarographic method로 측정한 콘택트렌즈 주변부의 산소투과율 감소량은 40.77%에서 49.13%의 분포로 나타났으며, 칼라 콘택트렌즈는 염료에 기인된 영향으로 산소투과율의 감소량이 더 크게 측정되었다.

• The Journal of Advanced Prosthodontics
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• 제1권1호
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• pp.1-5
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• 2009

STATEMENT OF PROBLEM. Poor wettability of denture relining materials may lead to retention problems and patient discomfort. PURPOSE. Purpose of this study is to compare and evaluate wettability of nine denture relining materials using contact angle measurements under air and water storage over time. MATERIAL AND METHODS. Nine denture relining materials were investigated in this study. Two heat-curing polymethyl-methacrylate(PMMA) denture base materials: Vertex RS, Lang, one self-curing polyethyl-methacrylate(PEMA) chairside reline resin: Rebase II, six silicone relining materials: Mucopren soft, Mucosoft, $Mollosil^{{R}}$ plus, Sofreliner Touch, GC $Reline^{TM}$ Ultrasoft, Silagum automix comfort were used in this experiment. Contact angles were measured using high-resolution drop shape analysis system(DSA 10-MK2, KRUESS, Germany) under three conditions(in air after setting, 1 hour water storage, and 24 hours water storage). Nine materials were classified into three groups according to material composition(Group 1: PMMA, Group 2: PEMA, Group 3: Silicone). Mean values of contact angles were compared using independent samples t-test and one-way ANOVA, followed by a Scheffe's post hoc analysis($\alpha$=0.01). RESULTS. Contact angles of materials tested after air and water storage increased in the following order: Group 1(PMMA), Group 2(PEMA), Group 3(Silicone). Heat-cured acrylic denture base resins had more wettability than silicone relining materials. Lang had the highest wettability after 24 hours of water storage. Silicone relining materials had lower wettability due to their hydrophobicity. Wettability of all denture relining materials, except Rebase II and $Mollosil^{{R}}$ plus, increased after 24 hours of water storage. CONCLUSIONS. Conventional heat-cured resin showed the highest wettability, therefore, it can be suggested that heat-cured acrylic resin is material of choice for denture relining materials.

• 대한기계학회논문집
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• 제13권5호
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• pp.820-830
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• 1989

본 논문에서는 타이어의 각 부분의 물성치 계산을 위한 식을 유한요소법에 적용할 수 있도록 제안하였다. 이 식은 강철 코드의 굽힙효과를 고려 하였으며, 특히 각 요소에서 전단변형이 일어나는 동안의 굽힘효과를 고려하였다. 유한요소 공식화는 가상일의 원리에 의하여 평형 방정식으로부터 유도하였고, Updated refer- ence coordinate에 대해 증분해석을 적용하여 Updated Lagrangian공식화를 하였다. 그리고 차량하중에 의하여 타이어가 노면에 접지될때의 응력상태를 게산할 수 있도록 접촉문제 공식화를 유한요소 공식화에 첨가 하였다.

• Tribology and Lubricants
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• 제22권6호
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• pp.314-319
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• 2006

In this paper, the friction and wear characteristics of contact type sealing unit far a water turbine have been presented. The sealing unit for a small hydropower generation is to stop a leakage of circulating water from an outside of an impeller to an inside of a rolling bearing. The friction heating between a seal ring and a seal seat may radically increase a surface temperature in which increase a power loss and wear on the rubbing surface. The surface wear strongly affect to the seal life of a mechanical face seal. In this study, the hardness of a stainless steel in which is a heat-treated is 892.8 in Victors hardness and the hardness of silicone carbide of SiC is 714.1 in Victors hardness. The surface hardness of a heat-treated stainless steel is 25% high compared with that of a ceramic material of SiC. The contact modes of rubbing surfaces are a dry friction, a water film friction and a mixed friction that is contaminated by a dust, silt, and moistures, etc. These two factors of a contact rubbing modes and a material property are very important parameters on the tribological performance such as a friction and wear between a seal ring and a seal seat in primary sealing unit. The experimental result shows that the surface hardness of a seal material is very important on the friction coefficient and a wear volume. Thus, the results recommend higher hardness of a seal material, which may reduce a friction loss and increase a wear life of primary seal components.

• 한국전기전자재료학회논문지
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• 제37권2호
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• pp.182-187
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• 2024

Currently, the most developed new energy source is solar energy. Because solar power is installed outside, it is exposed to many pollutants. Pollutants are causing the characteristics of solar energy to deteriorate. Therefore, this study aims to develop a water-repellent coating to prevent contamination of solar modules. Silica and Titania materials are mainly used as water-repellent coating materials. In this study, it was based on silica and the contact angle characteristics were measured according to the change in the amount of silica and ammonia water added and the number of coatings. As a result of the measurement, it was confirmed that the contact angle was more than 60 degrees when 0.5 mol of TEOS was added to 50 mL and 0.15 M when 1 mL of ammonia water was added to 296.47 ml of distilled water. And it was confirmed that the contact angle improved when the number of coatings was applied twice. A water-repellent coating material was applied to low iron tempered glass used to protect dye-sensitized solar cell modules. The characteristics of the module were measured after spraying DI-Water on low-emission tempered glass with a water-repellent coating. As a result of the measurement, the efficiency of the module without application, the efficiency of the module coated once, and the module coated twice were 4.87%, 4.90%, and 4.91%, respectively. It was confirmed that the efficiency of the module increased by applying water-repellent coating. As a result of this study, it is determined that the water-repellent coating material will help improve solar power generation efficiency and lifespan by being self-cleaning and non-reflective.