• 한국산학기술학회논문지
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• 제18권1호
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• pp.216-221
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• 2017

폴리머 안경렌즈를 제조할 때 가시광선 영역에서 투과되는 빛을 증가시키고, 안경렌즈 표면에 형성되는 허상을 방지하는 반사방지 기능은 매우 중요하다. 본 연구에서는 굴절률 1.56, 1.60 및 1.67을 갖는 안경렌즈를 폴리머 렌즈 모노머 및 이염화 이부틸 주석 촉매제, 알킬 인산 에스터 이형제 등의 혼합물을 인젝션 몰드 방법으로 열중합 공정을 적용하여 제조하였다. 폴리머 안경렌즈 표면에서의 반사방지 효과를 조사하기 위하여 다층 박막 반사방지 코팅 구조(양면 또는 단면 코팅), 3층 박막의 Gaussian gradient-index profile 불연속 근사 반사방지 코팅 구조, 3층 박막의 quarter-wavelength 근사 반사방지코팅 구조 등 다양한 반사방지 코팅 구조를 설계하였고, E-beam 증착 시스템을 이용하여 열중합공정으로 제조된 폴리머 안경렌즈에 각각 코팅하였다. 폴리머 안경렌즈의 광학적 특성은 UV-visible spectrometer로 분석하였다. 반사방지 코팅 층을 구성하는 박막의 굴절률, 표면 거칠기 등의 소재 특성은 Ellipsometer와 원자힘 현미경(AFM)으로 분석하였다. 분석결과, 굴절률 1.56의 낮은 굴절률을 갖는 폴리머 안경렌즈에서 가장 효과적인 반사방지 코팅 구조는 다층 박막 반사방지 코팅 구조의 양면코팅이었다. 하지만 굴절률 1.67의 고굴절률 안경렌즈에 대해서는 3층 박막의 Gaussian gradient-index profile 불연속 근사반사방지 코팅 구조의 양면 코팅도 다층박막 반사방지 코팅구조의 양면코팅에 상응하는 반사방지 효과를 나타내었다.

• 한국표면공학회지
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• 제55권6호
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• pp.308-318
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• 2022

The surface modification and treatment using thermal plasma were reviewed in academic fields. In general, thermal plasma is generated by direct current (DC) and radiofrequency (RF) power sources. Thermal spray coating, a typical commercial process using thermal plasma, is performed by DC thermal plasma, whereas other promising surface modifications have been reported and developed using RF thermal plasma. Beyond the thermal spray coating, physical and chemical surface modifications were attempted widely. Superhydrophobic surface treatment has a very high industrial demand particularly. Besides, RF thermal plasma system for large-area film surface treatment is being developed. Thermal plasma is especially suitable for the surface modification of low-dimensional nanomaterial (e.g., nanotubes) by utilizing high temperature and rapid quenching. It is able to synthesize and modify nanomaterials simultaneously in a one-pot process.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.61-65
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• 2009

Window integrated solar collector is to simply install inside of the existing double glass window frame. Double glass window frame is consist of inner glass of Low-E coating and Silver coating, and outer glass of low iron reinforced glass. In order to secure natural lighting in a room, only 50% of window frame is covered with solar collectors. Solar absorption or transmission rate varies seasonally depending on sun angles. Part of inner glass where right behind of the solar plate is covered with silver coating to increase absorption rate of solar plate. The collector is made of a copper serpentine where aluminum fins are soldering. To improve the effect of insulation of inside of the window frame is recommend vacuum. As a result, we are making the 3th sample and will archieve below $F_RU_L=7.5W/m^2^{\circ}C$ that is the account of heat lossed, and above $F_R({\tau}{\alpha})=0.45$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.351-351
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• 2013

한국 전체 에너지 사용량 중약 24%의 에너지가 건축물 부분에 소비되고 있다. 건축물의 벽체나 유리창 등을 통해서 에너지 손실이 이루어지는데 유리창은 벽체에 비해 약 10배 이상 낮은 단열 특성을 가지고 있기 때문에 유리창을 통한 열손실량은 더 크다. 이러한 유리창 부분의 열손실 문제를 해결할 수 있는 방안으로 좋은 단열 특성 및 낮은 방사율을 가지고 있는 Low-e coating 방법을 사용하였다. 본 실험에서는 XG glass 기판 위에 IGZO/Ag/IGZO OMO 구조의 다층 박막을 증착하였다. RF magnetron sputtering방법을 이용하여 OMO 구조의 상부와 하부의 Oxide layer로 IGZO 박막을 증착하였다. 사용된 IGZO 타겟은 $In_2O_3$ (99.99%), $Ga_2O_3$ (99.99%), ZnO (99.99%)의 분말을 각각 1:1:1 mol% 조성비로 혼합하여 소결하여 제작하였다. Thermal Evaporator 장비를 이용하여 OMO 구조의 Metal layer로 Ag (99.999%)를 증착하였다. 실험 기판은 크기 $30{\times}30mm$의 0.7T XG glass를 사용하였다. OMO 구조의 산화층 IGZO 박막은 상/하층 동일 조건으로 기판 온도는 실온으로 고정하였으며, 초기 압력 $3.0{\times}10^{-6}$ Torr, 증착 압력 $3.0{\times}10^{-2}$ Torr, RF 파워 50W, Ar 유량 50 sccm로 고정시키고 증착 시간이 변화하면서 박막을 증착하였다. OMO 구조의 Metal layer로 Ag 증착 조건은 초기 진공도가 약 $6.0{\times}10^{-6}$ Torr 이하로 유지하고 기판을 2 Rpm의 속도로 회전시켰다. 이후 0.3 V로 Ag를 10분간 가열하여 충분히 녹인 후 Film Thickness Monitor로 두께를 확인하였다. OMO 다층 박막의 산화물층 변화에 따라 로이다층 박막의 구조적, 광학적 및 전기적 특성을 분석하였다. XRD 분석결과에 의하여 Bragg's 법칙을 만족하는 피크가 나타나지 않는 비정질 구조임을 확인할 수 있으며, AFM 분석결과에 통해서 최소 1.3 nm의 Roughness를 나타내었다. UV-Visible-NIR 분광광도계를 이용하여 다층 박막은 가시광선 영역에서 평균 80%의 광 투과성을 보여 IR 영역에서 평균 30% 투과하고 좋은 차단 특성을 나왔다. Low-e 특성을 갖는 유리창을 통해서 에너지 절약을 이룰 수 있는 것을 확인할 수 있었다.

• 접착 및 계면
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• 제24권3호
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• pp.105-111
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• 2023

최근 귀금속 산업을 포함한 다양한 산업 분야에 있어, 생물 부착 억제를 위한 코팅 방법에 대한 관심이 증가하고 있다. 특히, 패션 주얼리와 같이 피부에 밀착하여 접촉하는 악세사리나 귀걸이, 그리고 피어싱의 경우, 금속 표면의 오염으로 인하여 접촉 부위를 자극하거나 이상 반응을 유도할 수 있다. 이에 본 연구에서는 폴리에틸렌글라이콜 양 말단에 홍합의 접착 물질로 보고된 카테콜기를 도입하여 접착성 폴리에틸렌글라이콜을 합성하고, 이를 구리와 아연의 합금인 황동 표면에 코팅하여 생물 부착 억제 효과를 관찰하였다. 접착성 폴리에틸렌글라이콜이 코팅된 황동 표면은 우수한 세포 생존율을 나타낼 뿐 아니라, 단백질이나 세포의 부착을 억제하는 효과를 나타냈다. 그러므로 귀금속 산업 분야에 있어서 접착성 폴리에틸렌글라이콜을 이용한 다양한 응용이 기대된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.128-128
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• 2003

Electrochromism (EC) is defined as a phenomenon in which a change in color takes place in the presence of an applied voltage. Because of their low power consumption, high coloration efficiency, EC devices have a variety of potential applications in smart windows, mirror, and optical switching devices. An EC devices generally consist of a transparent conducting layer, electrochromic cathodic and anodic coloring materials and an ion conducting electrolyte. EC has been widely studied in transition metal oxides(e.g., WO$_3$, NiO, V$_2$O$\sub$5/) Among these materials, WO$_3$ is a most interesting material for cathodic coloration materials due to its lush coloration efficiency (CE), large dynamic range, cyclic reversibility, and low cost material. WO$_3$ films have been prepared by a variety of methods including vacuum evaporation, chemical vapor deposition, electrodeposition process, sol-gel synthesis, sputtering, and laser ablation. Sol-gel process is widely used for oxide film at low temperature in atmosphere and requires lower capital investment to deposit large area coating compared to vacuum deposition process.

• 한국초전도ㆍ저온공학회논문지
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• 제7권1호
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• pp.5-8
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• 2005

MOD Process using metal acetates or trifluoroacetates has been considered to be a strong candidate for a low cost fabrication process for coated conductor with high $J_e$. Recently, an economical MOI) process has been developed for coated conductor with high $J_c$ using low cost starting materials such as YBCO powders. YBCO thin films prepared by single coating on LAO substrate with this modified oxide-precursor solution gives transport $I_c$ of 100A/cm-w and the $J_c$ value of $2.9MA/cm^{2}$ (77K, Self-field). The YBCO coated conductor prepared by single coating with $CeO_2/IBAD-YSZ/SS$ tape gives transport $I_c$ of 50A/cm-w in 2cm. Characterization with XRD, SEM shows that the YBCO layers were epitaxially grown and exhibit well-developed dense micro-structures. This newly developed oxide-precursor based MOD process will provide a low cost route to coated conductor with high $J_c$.

• Nuclear Engineering and Technology
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• 제43권6호
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• pp.557-566
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• 2011

A cold spray coating (CSC) of copper was studied for its application to a high-level radioactive waste (HLW) disposal canister. Several copper coatings of 10 mm thick were fabricated using two kinds of copper powders with different oxygen contents, and SS 304 and nodular cast iron were used as their base metal substrates. The fabricated CSC coppers showed a high tensile strength but were brittle in comparison with conventional non-coating copper, hereinafter defined to as "commercial copper". The corrosion behavior of CSC coppers was evaluated by comparison with commercial coppers, such as extruded and forged coppers. The polarization test results showed that the corrosion potential of the CSC coppers was closely related to its purity; low-purity (i.e., high oxygen content) copper exhibited a lower corrosion potential, and high-purity copper exhibited a relatively high corrosion potential. The corrosion rate converted from the measured corrosion current was not, however, dependent on its purity: CSC copper showed a little higher rate than that of commercial copper. Immersion tests in aqueous HCl solution showed that CSC coppers were more susceptible to corrosion, i.e., they had a higher corrosion rate. However, the difference was not significant between commercial copper and high-purity CSC copper. The decrease of corrosion was observed in a humid air test presumably due to the formation of a protective passive film. In conclusion, the results of this study indicate that CSC application of copper could be a useful option for fabricating a copper HLW disposal canister.

• Corrosion Science and Technology
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• 제18권6호
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• pp.277-284
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• 2019

External corrosion control of buried pipe can be achieved by the combination of barrier coating and cathodic protection. Coating damage and deterioration can be induced by many reasons; damage during handling and laying, enhanced failure at low temperatures, failure during commissioning and operation, disbanding due to inadequate surface cleaning, rock penetration during installation and service etc. This work focused on the effect of survey conditions on the reliability of coating flaw detection of buried pipes. The effects of applied voltage and anode location on the detection reliability of coating flaw of buried pipe in soil with the resistivity of ca. 25.8 kΩ·cm were discussed. Higher applied voltage increased the detection reliability, regardless of buried depth, but deeper burial depth reduced the reliability. The location of the anode has influenced on the detection reliability. This behaviour may be induced by the variation of current distribution by the applied voltage and buried depth. From the relationship between the applied voltage and reliability, the needed detection potential to get a desire detection reliability can be calculated to get 100% detection reliability using the derived equation.

• 펄프종이기술
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• 제31권1호
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• pp.72-79
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• 1999

The binder plays important roles in determining the quality of pigment coating. In addition to its primary role of binding the pigment to the base paper, the binder performs several other important functions. The binder, also referred to as the adhesive, is the dominant in the aqueous phase of the formulation. Thus it plays a major role in determining viscosity, rheology, water release, and setting time for the coating. Latices based on styrene-butadiene dominate the market for synthetic paper coating binders. Consumption is high and is expected to increase further due to the present tendeyncy toward high-solids coating. The purpose of this study is understanding the impact of various parameters of latex(i.e. Tg, Particle size) affecting prontabilities and optical properties of the coated papers, as well as providing basic information on the use of amphoteric latex for improving print qualities of coated papers. Recently, amphoteric latices, Which are cationic at low pH's but turn anionic at high pH's have attracted interests of paper scientists and engineers. Therefore we investigated the effect of the Tg(glass transition temperature) and particle size of amphoteric latex on the coating qualities. We also studied the effect of mixing ratios (Amphoteric / Anionic)of latex on the coating qualities. Our results showed that Tg and particle size of amphoteric latex have to be controlled for optimizing coated paper qualities. The formulation consisting of 10 parts of amphoteric latex and 5 parts of anionic latex gave best results in ink receptivity, smoothness, air permeability, opacity and sheet gloss. If the results hold for the industrial paper coatings, the amount of expensive amphoteric latex can be reduced while achieving best available printing quality.