• 콘크리트학회지
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• 제6권3호
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• pp.173-179
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• 1994

국내 사용을 위하여 시험 생산된 에폭시 도막 철근에 대하여 운반, 가공시에 요구되는 기계적인 성능을 중심으로 품질을 시험 평가하고 시공 지침을 제안하기 위하여 기초적 자료를 축적하고자 하였다. 시험결과 에폭시 도막의 부착성능과 내마모성은 규격의 요구조건을 만족시키는 결과를 보이고 있다. 내굴곡성능도 규격의 기준은 만족시키고 있으나 도막이 두꺼울수록 내굴곡성이 약해지며 특히, 가공시 굽힙 각도는 $120^{\circ}$를 초과하지 않아야 할 것으로 판단되었다. 또한 저온에서 굴곡시 상당수의 도막 균열을 나타내어 저온에서의 가공에 대하여 제한이 확인되었다. 충격에 대한 저항성능은 규격은 만족되고 있으나 다소 약함을 보이고 있어 가공 운반시 주의가 요구될 것으로 판단된다. 국내에서 시험 생산된 에폭시 도막의 성능 시험 결과, 규격에서 요구되는 기계적인 성능을 대체로 만족하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.75-76
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• 2008

In this study, texture development and bending characteristics of strong {0002} textured were observed. AZ31 Mg alloy sheets were prepared along the angle of 0 and 12.5 degrees to the lolling direction or {0002} texture. Prepared samples with different angles to the rolling direction were rolled at room temperature condition and after subsequent heat treatment to investigate texture with x-ray diffractometer, respectively The specimen having along the angles of 0 degree to rolling direction shows the highest load and 12.5 degrees specimen shows the highest displacement among any other specimens in bending test.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.158-162
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• 1994

Test results to evaluate the mechanical properties of epoxy-coated bars and corrosion protection characteristics of epoxy coating on the bars are described. The results show good adhesion and abrasion resistance satisfying the requirements in relevant standards. The test results also show that for a coating thickness ranging from 150${\mu}{\textrm}{m}$ to 300${\mu}{\textrm}{m}$, satisfactory results are obtained regarding bendability. Cautions shall be required when bending epoxy-coated bars at a high bending degree and at a low temperature. The results of accelerated corrosion tests show good corrosion resistance. However, surface defects from the steel itself and insufficient blast-clean process form weak points resulting blistering or disbonding of the coating. The use of epoxy-coated bars is expected to help protect corrosion of reinforcement and extend the service life of reinforced concrete structures.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.294-294
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• 2010

Over the last decade, dye-sensitized solar cell (DSSC) has attracted much attention due to the high solar-to-electricity conversion efficiency up to 10% as well as low cost compared with p-n junction photovoltaic devices. DSSC is composed of mesoporous TiO2 nanoparticle electrodes coated with photo-sensitized dye, the redox electrolyte and the metal counter electrode. The performances of DSSC are dependent on constituent materials and interface as well as device structure. Replacing the heavy glass substrate with plastic materials is crucial to enlarge DSSC applications for the competition with inorganic based thin film photovoltaic devices. One of the biggest problems with plastic substrates is their low-temperature tolerance, which makes sintering of the photoelectrode films impossible. Therefore, the most important step toward the low-temperature DSSC fabrication is how to enhance interparticle connection at the temperature lower than $150^{\circ}C$. In this talk, the key issues for high efficiency plastic solar cells will be discussed, and several strategies for the improvement of interconnection of nanoparticles and bendability will also be proposed.

• Corrosion Science and Technology
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• 제9권2호
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• pp.67-73
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• 2010

Niobium microalloying is effective in hot-rolled and cold-rolled steels by providing a fine-grained microstructure resulting in increased strength. To optimize the strengthening effect, alloy design and hot-rolling conditions have to be adapted. As a key issue the dissolution and precipitation characteristics of Nb are discussed in particular with regard to the run-out table conditions. It is then considered how the hot-rolled microstructure and the solute state of Nb interact with the hot-dip galvanizing cycle. The adjusted conditions allow controlling the morphology and distribution of phases in the cold-rolled annealed material. Additional precipitation hardening can be achieved as well. The derived options can be readily applied to produce conventional HSLA and IF high strength steels as well as to modern multiphase steels. It will be explained how important application properties such as strength, elongation, bendability, weldability and delayed cracking resistance can be influenced in a controlled and favorable way. Examples of practical relevance and experience are given.

• 열처리공학회지
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• 제27권1호
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• pp.1-9
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• 2014

For connector material applications, the influence alloying elements of Mn, Cr, Fe, and Ti and cold rolling reduction on the mechanical property, electrical conductivity and bendiability of Cu-Ni-Si-P alloy was investigated. The hot rolled plates were solution treated at $980^{\circ}C$ for 1.5 h, quenched into water, cold rolled by 10% and 30% reduction in thickness, and then aged at $440{\sim}500^{\circ}C$ for 3, 4, 5 times. respectively. Cu-Ni-Si-P-x alloys cold rolled by 10 reduction before heat treatment have a good bendability compare to cold rolled by 30 reduction. Cu-3.4Ni-0.8Si-0.03P-0.1Ti shows the peak strength value of 759 MPa, an electrical conductivity of 39%IACS, an elongation of 10% and a hardness of 256 Hv aged at $440^{\circ}C$ for 6 hrs. Thus it is suitable for lead frame and connector.

• 폴리머
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• 제38권6호
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• pp.720-725
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• 2014

Hydride terminated polydimethylsiloxane과 allyl amine을 hydrosilylation 반응으로 aminopropylpoly-dimethylsiloxane을 합성하고, 이를 hexamethylenediisocyanate(HDI)의 고리화 반응으로 제조된 cyclic HDI trimer와 반응시켜 urea결합으로 결합된 polydimethylsiloxane 변성 urea을 제조하였다. Polydimethylsiloxane 변성 urea의 말단에 있는 isocyante기와 2-hydroxyethylmethacrylate를 반응시켜 말단에 multi acrylate기가 도입된 polydimethylsiloxane 변성 urea/acrylate(PUA)를 제조하였다. 제조한 화합물의 구조를 FTIR, $^1H$ NMR로 확인하였으며, PUA에 아크릴계 단량체, 광 개시제, 용매 등을 여러 가지 조성비로 혼합하여 코팅 액을 제조하였으며 이를 PET 필름에 도포하고 UV을 조사하여 고경도의 유연성을 갖는 코팅 막을 제조하였다. 제조한 코팅 막의 연필 경도는 3H, 접촉각은 $82^{\circ}$, bendability는 $7{\phi}$까지 scratch가 발생하지 않았다.

• 열처리공학회지
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• 제33권6호
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• pp.277-283
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• 2020

Cu-Co-Si based alloy has a strengthening mechanism for Co₂Si intermetallic compounds deposited on the copper matrix after aging treatment and the solution treatment has a key influence on the strength and electrical conductivity of the final products. In this paper, the Cu-1.6%Co-0.38%Si alloy was fixed at the time and the solution treatment temperature was set at a temperature in the range of 800 to 950℃, and the change in mechanical properties was observed by fixing the temperature at 950℃ and changing the time. The microstructure was observed using an electron microscope and an optical microscope, and the changes in hardness, electrical conductivity, and bending workability after aging treatment were investigated. When the solution treatment time is less than 20 seconds, the solution treatment is not sufficient and the formation of precipitates contributing to the increase in hardness decreases and the hardness decreases after the aging treatment, and in more than 50 seconds, the hardness decreases due to the coarsening of the grains and the bending workability got worse.

• 한국표면공학회지
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• 제52권1호
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• pp.6-15
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• 2019

Metal-halide perovskite (MHP) solar cell is a promising candidate for next-generation flexible devices and the BIPV (Building-integrated photovoltaics) because it can exhibit high power conversion efficiencies over 23%, good bendability and low processing cost. However, MHP solar cells are commonly fabricated by the spin coating that is not a reliable method to produce large-scale commercial solar cells. A shear coating can be one of the potential candidates for the large-scale deposition method of MHP films. In this work, the influences of the process parameters such as solvents of precursor solution, substrate temperature, concentrations of precursor solution, and annealing time on the thin film growth of MHP were investigated for the shear coating process. This study presents the possibility of the shear coating process for large-scaled perovskite film fabrication and reveals the role of process condition in the thin film growth of perovskites.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.314-314
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• 2013

Recently, flexibility is one of the hottest issues in the field of electronic devices. For flexible displays or solar cells, a development of transparent conductive electrodes (TCEs) with flexibility, bendability and foldability is an essential element. Hundreds of nanometers indium-tin-oxide (ITO) films have been widely used and commercialized as a transparent electrode, but their brittleness make them difficulty to apply flexible electronics. Many researchers have been studying for flexible TCEs such as a few layers of graphene sheets, carbon nanotube networks, conductive polymer films and combinations among them. Although gained flexibility, their transmittance and resistivity have not reached those of commercialized ITO films. Metal grids electrode cannot act as TCEs only, but they can be used to lower the resistance of TCEs with few losses of transmittance. However, the possibility of device shortage will be rise at the devices with metal grids because a surface flatness of TCEs may be deteriorated when metal grids are introduced using conventional methods. In our research, we have developed hybrid TCEs, which combined tens of nanometers ITO film and metal grids which are embedded in flexible substrate. They show $13{\Omega}$/${\Box}f$ sheet resistance with 94% of transmittance. Moreover, the sheet resistance was maintained up to 1 mm of bending radius. Also, we have verified that flexible organic light emitting diodes and organic solar cells with the TCEs showed similar performances compared to commercial ITO (on glass substrate) devices.