• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.79-80
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• 2022

A method for repairing cracks using low-viscosity resins has been proposed as a construction method that can quickly repair roads from deterioration. However, when the viscosity of the epoxy resin is high, there is a limit in that it is difficult for the material to penetrate into microcracks and cracks in the concrete top plate. In this study, an epoxy thin-layer pavement repair method was developed using low-viscosity PMMA (Poly methyl methacrylate) to repair microcracks on the pavement surface and pavement layer and reinforce the pavement surface. Materials necessary for the thin-layer packaging method were developed, and performance was evaluated to meet the epoxy binder quality standards. As a result, all materials met the required performance.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.287-293
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• 2009

The passivation films with epoxy layer on LiF, $SiN_x$ and LiF/$SiN_x$ inorganic layer were fabricated on OLED to protect device from the direct damage of $O_2$ and $H_2O$ and to apply for a buffer layer between OLED device and passivation multi-layer with organic/inorganic hybrid structure as to diminish the thermal stress and expansion. Red OLED doped with 1 vol.% Rubrene in $Alq_3$ was used as a basic device. The device structure was multi-layer of ITO(150 nm) / ELM200_HIL(50 nm) / ELM002_HTL(30 nm) / $Alq_3$: 1 vol.% Rubrene(30 nm) / $Alq_3$(30 nm) / LiF(0.7 nm) / Al(100 nm). LiF/epoxy applied as a protective layer didn't contribute to the improvement of life time. While in case of $SiN_x$/epoxy, damage was done in the passivation process because of difference in heat expansion between films which could occur during the formation of epoxy film. Using LiF/$SiN_x$/epoxy improved lifetime significantly without suffering damage in the process of forming films, therefore, the best structure of passivation film with inorganic/epoxy layers was LiF/$SiN_x$/E1.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.7
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• pp.578-583
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• 2001

The bushing for high voltage and large and power should endure weight of itself and force of pushing from contact with circuit breaker. Like this, epoxy mold bushing has to be strong without fault. However, the external circumstances and internal factors was caused by partial discharge, flashover and dielectric breakdown. Therefore, to remove external factor of defect and to prevent the internal cracks and cavity generated from the contraction on interface of Cu-Epoxy, we should form semi-conductive layer on Cu bar by carbon. Then, the PD properties and the insulation qualities of epoxy mold type bushing was able to improved by roles of cushions for the direction of diameter and by effects fo natural sliding like as separated from conductor for the direction of length. So, in this work, we could prove the method of semi-conductive layer in making the long conductor.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.334.1-334.1
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• 2016

다른 재료에 비해 에너지 변환 효율의 관점에서 높은 경쟁력을 가진 결정질 실리콘은 지난 수십 년 동안 그 특성이 태양전지 분야에 널리 이용되어 왔다. 하지만 결정질 실리콘 웨이퍼는 일반적으로 제조 단계에서 많은 양의 에너지를 소비하고 절단 단계에서 절단 손실(Kerf-loss)이 발생된다. Epoxy Resin을 이용한 Kerf-less Wafering은 초박형 실리콘 웨이퍼 제조 기술 중 하나로, 비교적 간단한 장비와 공정을 통하여 절단 손실 없이 $50{\mu}m$이하의 초박형 실리콘 웨이퍼를 얻을 수 있는 기술이다. 실리콘과 Epoxy Resin 간의 열팽창 계수 차이를 이용하여 초박형 실리콘을 박리 시키는 기술로, 실리콘 기판 위에 Epoxy Resin으로 stress inducing layer를 올려 공정을 진행한다. stress inducing layer를 경화시키는 열처리가 끝나고 급냉되는 과정에서 stress inducing layer에 의해 실리콘 기판에 큰 응력이 가해지게 되고 실리콘 기판에 crack이 발생된다. 공정이 계속 됨에 따라 발생된 crack은 실리콘 표면과 평행한 방향으로 전파 되고 초박형 실리콘 layer가 실리콘 기판에서 박리 된다. 본 실험에서 중요한 공정 변수로는 stress inducing layer의 구성성분 및 두께, 열처리 온도 및 시간, cooling rate 등이 있다. 이러한 공정 변수들을 조절 하여 Epoxy Resin을 이용하여 $100{\mu}m$ 이하의 박리된 wafer를 얻을 수 있었다. 박리된 wafer의 단면과 두께를 Scanning Electron Microscopy(SEM)을 통해 관찰 하였고, 이를 통해 초박형 실리콘 박리 공정에 대한 연구를 진행하였다.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.35-39
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• 2018

This paper deals with the relaxation of singular stresses developed in an epoxy adhesive at high temperature. The interface stresses are analyzed using BEM. The adhesive employed in this study is an epoxy which can be cured at room temperature. The adhesive is assumed to be linearly viscoelastic. First, the distribution of the interface stresses developed in the adhesive layer under the uniform tensile stress has been calculated. The singular stress has been observed near the interface corner. Such singular stresses near the interface corner may cause epoxy layer separated from adherent. Second, the interfacial thermal stress has been investigated. The uniform temperature rise can relieve the stress level developed in the adhesive layer under the external loading, which can be viewed as an advantage of thermal loading. It is also obvious that temperature rise reduces the bonding strength of the adhesive layer. Experimental evaluation is required to assess a trade-off between the advantageous and deleterious effects of temperature.

• Composites Research
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• v.14 no.6
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• pp.38-46
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• 2001

In this study, An optimization code that can design microwave absorbing composite laminates is developed, and 3-layered microwave absorbing composite laminates are developed by optimizing the thickness of each layer. The layers are 3 different composite laminates. Many variables including lay-up angles of electromagnetically orthotropic composite layer can be considered in this code. The developed laminate is composed of an impedance matching layer of glass/epoxy fabric laminate, a glass/epoxy fabric laminate layer containing aluminum filler and carbon/epoxy fabric laminate layer. Permittivities of the materials are obtained using a network analyzer and a coaxial air line.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.4
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• pp.388-394
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• 2008

For purpose of anti-static film remaining unchanged in the condition of $160^{\circ}C$, organic solvent, acid and base solution $0.01\sim0.03{\mu}m$ particles of Sb doped tin oxide(ATO) were grafted by 3-Glycidyloxypropyltrimethoxysilane(GPTS) for improving interfere bonding force between ATO and epoxy resin. The particles were dispersed in 2-methoxyethanol with YD-I28(Bisphenol A type epoxy resin, Kukdo chemical) and 1-imidazole as hardener. The anti-static solutions were coated on PI film as thickness of $0.1{\mu}m$. Surface resistivity of anti-static film containing conductive polymer became $10^{12}\Omega/\Box$ after 32 hours in $160^{\circ}C$. The surface resistivity of ATO grafted by GPTS / Epoxy coating layer remained as $10^{7.6}\Omega/\Box$ in $160^{\circ}C$ for 7 days. ATO grafted by GPTS / Epoxy coating layer coated on PI film was dipped in acetone for 7 days. The surface resistivity remained unchanged as $10^{7.6}\Omega/\Box$. The anti-static layer dipped in water solutions containing each KOH 10 wt % and $H_2SO_4$ 2 wt% was ultra-sonicated for 10 minutes per once until 30th. The surface resistance of anti-static layer containing ATO grafted by GPTS remained unchanged.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.1
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• pp.34-40
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• 2012

In this study, effects of bonding agent, e.g. epoxy, on the behavior of fundamental guided wave modes propagated in FRP plate bonded on a concrete, are investigated. Global matrix model of multilayered FRP-epoxy-concrete system was constructed to obtain the velocity and attenuation dispersion curves of the fundamental A0 and S0 modes. Two variables, thickness and elastic modulus of epoxy layer, were considered in the dispersion analysis. It was found that both the thickness and the elastic modulus of epoxy layer greatly affect the phase velocity and attenuation of S0 mode while those are negligible for A0 mode. Based on the results, it was concluded that S0 mode is more effective than A0 mode for bonding condition assessment for FRP plate bonded concrete.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.380-380
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• 2013

본 논문에서는 외기 환경 요인 중에서 H2O와 O2의 영향으로 성능이 저하되는 유기박막트랜지스터(OTFT)의 수명시간 향상을 위하여 필요한 passivation layer의 효과에 대하여 알아 보았다. OTFT에 기존의 액상 공정이나 증착 공정으로 단일 passivation layer또는 다층 passivation layer를 형성하는 방식과는 다르게 향후에 산업 전반에 적용이 기대되는 것을 고려하여 제작 공정의 간편성을 위하여 film 형태로 되어 있는 열경화성 epoxy resin film으로 passivation layer를 구현하는 방법을 사용하여 OTFT의 storage stability를 평가하였다. passivation layer가 없는 OTFT와 열경화성 epoxy resin film으로 passivation된 OTFT의 전기적 특성이 서로 비교 평가되었으며 또한 30일 동안 온도 $25^{\circ}C$ 상대습도 40%의 환경을 갖는 Desicator 안에서 소자를 보관하여 시간에 따른 전기적 특성 변화를 검증하여 epoxy resin film의 passivation layer으로의 적용가능성을 검증하였다. 결과적으로 30일 후의 passivation layer가 없는 OTFT의 전기적 특성은 매우 낮게 떨어진 반면에 epoxy resin film으로 passivation layer가 구현된 OTFT의 mobility는 $0.060cm^2$/Vs, VT는 -0.18 V, on/off ratio는 $3.7{\times}10^3$으로 초기의 소자 특성이 잘 유지되는 결과를 얻었다. OTFT는 Flexible한 polyethersulfone (PES)기판에 게이트 전극이 하부에 있는 Bottom gate 구조로 제작되었고 채널 형성을 위한 유기반도체 재료로 6,13-bis (triisopropylsilylethynyl) (TIPS) pentacene이 사용되었고 spin coating된 Poly-4-vinylphenol (PVP)가 게이트 절연체로 사용되었다. 이때 Au전극은 Shadow mask를 이용하여 증착하였다. 또한 OTFT의 채널 길이 $100{\mu}m$, 채널 폭 $300{\mu}m$의 영역에 Drop casting법을 사용하여 채널을 형성하였다. 물리적 특성은 scanning electron microscopy (SEM), scanning probe microscopy (SPM), x-ray diffraction (XRD)를 사용하여 분석하였고, 전기적 특성은 Keithley-4200을 사용하여 추출하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.627-632
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• 1998

This study deals with the effect on adhesive strength properties of waterproofing and reinforcing layer and mortar or concrete substrate applicated by epoxy resin anticorrosive and bonding materials. Properties of adhesive strength change condition of concrete substrate, temperature, moisture, curing and cleaning and so on. The purpose of this study is that it makes the estimation value of bond strength of concrete wall and epoxy resin layer when coated epoxy resin as anticorrosive materials for durability performance estimation depend on concrete watertightness, and when penetrated epoxy resin for the reinforcement of concrete used the carbon fiber sheet.