• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.129-133
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• 1995

The purpose of this study is to evaluate the flexural bond performance in beam using 3-types anti-corrosion coatings. For the test. we used $15\times\times20\times110cm$ R.C beams, in which the epoxy, the red lead, and the cementitious anti-corrosion coating re-bars used. The results of test using these 3-type anti-corrosion coatings are shown that the flexural bond performance of cementitious anti-corrosion coating rebar in R.C beam is superior to other anti-corrosion coatings rebars.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.343-348
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• 2000

The purpose of this study is to clarify properties adhesive strength of polymer-cement slurry for coated reinforcing bars. The epoxy coating material is superior to performance of anti-corrosion but lately age adhesive strength between concrete raise to structural problems. However, polymer dispersion with excellent performance of elasticity and adhesion can solve this problems. From the test results. adhesion of steel with polymer cement slurry using St/BA emulsion is show excellent without concerned coating thickness, and polymer cement slurry using St/BA emulsion is show adhesion in tension 1.2~2.2MPa at polymer cement ratio 50% of more.

• Corrosion Science and Technology
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• 제21권2호
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• pp.121-129
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• 2022

A study on water-based epoxy coated on mild steel using the electroplating method was conducted to optimize the process parameters for dry film thickness to achieve superior paint quality at optimal cost in an automotive plant. The regression model was used to adjust various parameters such as electrode voltage, bath temperature, processing time, non-volatile matter, and surface area to optimize the dry film thickness. The average dry film thickness computed using the model was in the range of 15 - 35 ㎛. The error in the computed dry film thickness with reference to the experimentally measured dry film thickness value was - 0.5809%, which was well within the acceptable limits of all paint shop standards. Our study showed that the dry film thickness on mild steel was more sensitive to electrode voltage and bath temperature than processing time. Further, the presence of non-volatile matter was found to have the maximum impact on dry film thickness.

• 한국산업융합학회 논문집
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• 제27권2_2호
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• pp.357-361
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• 2024

Halloysite nanotube (HNT) has a nanotube structure with the chemical formula of Al₂Si₂O₅(OH)₄·nH₂O and is a natural sediment of aluminosilicate. HNT has been used as additive to improve the mechanical properties of epoxy composites with exchange of amine group as a terminal functional group using huge amount of organic solvents. In order to save time and simplify complicated procedures, a dry coating machine was designed and used for amine group exchange in previous research. For better applications, it was conducted with different parameters and with scale up settings. Best condition was found to reduce usage of solvent, time and man power.

• 한국지반환경공학회 논문집
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• 제19권3호
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• pp.15-24
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• 2018

전자기파는 주변 매질의 전기전도도와 유전율에 민감한 영향을 받기 때문에 지반의 특성을 평가하는데 널리 이용되고 있다. 본 연구에서는 염수환경에서도 다양한 농도의 중금속을 검측하기 위하여 시간영역반사법을 이용한 전자기파 측정 프로브를 제작하였다. 중금속으로는 구리를 사용하였으며, 실내 실험을 통해 구리 농도에 따라 적용 가능한 프로브를 선정하였다. 실내 실험에서는 염도 3%의 염수에 용해된 구리의 농도가 0, 0.01, 0.05, 0.1, 0.5, 1, 5, 그리고 10mg/L가 되도록 8단계로 용액을 조성하였다. 프로브는 염수에서도 전자기파를 측정할 수 있도록 5가지의 각기 다른 절연재로 코팅하여 비교하였다. 코팅재로는 에폭시, 탑코트, 바니쉬, 아크릴페인트, 히팅튜브를 사용하였으며 코팅재에 따른 전자기파의 신호 특성을 분석하였다. 실험 결과, 아크릴페인트와 히팅튜브로 코팅된 프로브는 구리 농도에 따른 신호 변화가 관측되지 않았으며, 에폭시, 탑코트, 바니쉬의 경우 구리 농도가 증가함에 따라 반사된 전자기파의 전압의 크기가 감소하는 것으로 나타났다. 에폭시로 1회 코팅한 프로브와 탑코트로 코팅한 프로브는 구리의 농도가 5mg/L 이하일 때 민감한 반응을 보였으나 에폭시로 2회 코팅한 경우, 구리의 농도가 5mg/L보다 클 때 더 민감하게 반응하였다. 본 연구의 결과는 절연재로 코팅된 시간영역반사법을 이용한 전자기파 측정 프로브가 염수에 녹아있는 중금속의 농도를 평가하는데 활용될 수 있음을 보여준다.

• Journal of Life Science
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• 제9권2호
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• pp.19-23
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• 1999

Bisphenol-A and related conpounds recently have been reported to be estrogenic since it has been demonstrared in laboratory stuides that they mimic the effects of estrogen. Bisphenol-A refered to as "environmental estrogen" are suspected of causing health effect in living body through disruption of endocdrine system. In this review, the occurrence, environmental fate, and biological effects of bisphenol-A are presented. To provide understanding to the potential for endocrine disruption due to environmental estrogen, the physiology of bisphenol-A mammalian and fish is also reviewed. For empty can, the migrationof bisphenol-A form food conducted epoxy coating was effected by the test conditions and it increased in order to water and 4% acetic acid. Extracts from foods packed in lacquer coated can also showed estrogenic activity. Bisphenol-A was found as a contaminant not only in the liquid food cans, but also in water autoclave in can. The used of coating certain food-packaging material may require closer scrutiny to determine when bisphenol-A contribute to advert exposure of consumers to estrogenic xenobiotics. Human breast cancer MCF cell added bisphenol-A cultivated to study the ability of bisphenol-A to elicit of bisphenol-A estrogenic bioresponse in this system. Bisphenol-A, similar to estradiol, induced PR activation in transiently transfected anterior and posterior pituitary cells.

• 한국환경과학회지
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• 제32권6호
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• pp.477-482
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• 2023

Halloysite nanotube (HNT) has a nanotube structure with the chemical formula of Al₂Si₂O₅(OH)₄ · nH₂O and is a natural sediment of aluminosilicate. A lot of research has been conducted to improve the mechanical properties of epoxy composites by generating interactions between HNTs and polymers through surface treatment of HNTs, such as exchange of amine group as a terminal functional group. However, most of the surface modification methods are performed under wet conditions, which require a relatively large amount of time, manpower and solvent. In order to save time and simplify complicated procedures, a dry coating machine was designed and used for amine group exchange. Comparing the XPS results, it was found that the results of NH₂-HNT prepared using a dry coating machine and the substitution through the wet method were not significantly different, and it has been confirmed that the amount of solvent used and the time savings can be made.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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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.

• Composites Research
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• 제31권3호
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• pp.83-87
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• 2018

An object in the Low Earth Orbit (LEO) is affected by many environmental conditions unlike earth's surface such as, Atomic oxygen (AO), Ultraviolet Radiation (UV), thermal cycling, High Vacuum and Micrometeoroids and Orbital Debris (MMOD) impacts. The effect of all these parameters have to be carefully considered when designing a space structure, as it could be very critical for a space mission. Polybenzimidazole (PBI) is a high performance thermoplastic polymer that could be a suitable material for space missions because of its excellent resistance to these environmental factors. A thin coating of PBI polymer on the carbon epoxy composite laminate (referred as CFRP) was found to improve the energy absorption capability of the laminate in event of a hypervelocity impact. However, the overall efficiency of the shield also depends on other factors like placement and orientation of the laminates, standoff distances and the number of shielding layers. This paper studies the effectiveness of using a PBI coating on the front bumper in a multi-shock shield design for enhanced hypervelocity impact resistance. A thin PBI coating of 43 micron was observed to improve the shielding efficiency of the CFRP laminate by 22.06% when exposed to LEO environment conditions in a simulation chamber. To study the effectiveness of PBI coating in a hypervelocity impact situation, experiments were conducted on the CFRP and the PBI coated CFRP laminates with projectile velocities between 2.2 to 3.2 km/s. It was observed that the mass loss of the CFRP laminates decreased 7% when coated by a thin layer of PBI. However, the study of mass loss and damage area on a witness plate showed CFRP case to have better shielding efficiency than PBI coated CFRP laminate case. Therefore, it is recommended that PBI coating on the front bumper is not so effective in improving the overall hypervelocity impact resistance of the space structure.

• 한국해양공학회지
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• 제24권5호
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• pp.60-66
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• 2010

Zinc has a number of characteristics that make it well suited for use as a coating to protecting iron and steel products from corrosion. Its excellent corrosion resistance in most environments accounts for its successful use as a protective coating on a variety of products and in many exposure conditions. The excellent field performance of zinc coatings results from their ability to form dense, adherent films that corrode at a rate that ranges from 1% to 10% of the corrosion rate of ferrous materials, depending on the environment. Recently, EU RoHS and EU ELV prohibited the use of materials that adversely affect the environment, such as Pb, Hg, Cd, and $Cr^{+6}$. In this study, environmentally-friendly, Cr-free solutions (epoxy solution, acrylic solution, and urethane solution S-700) and organic/inorganic solution with Si; LRO-317) were used to evaluate the corrosion resistance of zinc-coated steel subjected to a saltwater spray for 72 hours. The coating of urethane solution (S-700) was best among the three kinds of solution with heat treatment during five minutes at $190^{\circ}F$. Test specimens with S-700 and LRO-317 coating were heat treated in a drying oven at 170, 180, 190, 200, and $210^{\circ}C$ for five minutes. The results show that the optimum corrosion resistance was $190^{\circ}C$ in EGI and $170^{\circ}C$ in HDGI, respectively.