• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.90-90
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• 2010

Cycloaliphatic Epoxy와 Bisphenol Epoxy를 각각 mol-wt%비 (80:20, 50:50, 20:80)로 혼합하고 Epoxy Silaned Silica, 바ed Silica, Spherical Silica, ATH(Aluminum Trihydrate)를 충진하여 내트래킹 특성 및 인장강도, 충격강도 등의 기계적 강도를 비교하였다. Cycloaliphatic 수지는 Huntsman사(社)의 CY5622, Bisphenol 수지는 Hexion사(社)E의 Epikote2200을 사용하였으며, Silaned Silica 및 Fused Silica는 Quatzwerke사(社)의 W12, FW12를 사용하였다. 전체 혼합물 중, 에폭시는 약 36%, 실리카는 약 34~540%, ATH는 약 10~30% 이다. 실험결과, ATH 함량이 높은 조성 및 Epoxy Silaned Silica를 사용한 조성과 Cycloaliphatic 혼합비율이 높은 조성이 우수한 내트래킹 특성을 보였다. 또한, Silica의 함량이 증가할수록 기계적 강도가 증가하였으며, Silaned Silica를 사용하였을 때 가장 우수한 특성을 나타내었다. 본 실험의 결과를 통해 옥외용 내트래킹 특성 규격인 IEC60587 4.5kV/6h를 만족하는 조성에 대해 가늠이 가능하였고, 각 조성에 따른 기계적 강도의 확인이 가능하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.153-156
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• 2005

Nondestructive sensing of electrospun PYDF web and multi-wall carbon nanotube (MWCNT)/epoxy composites were investigated using electro-micromechanical technique. Electrospinning is a technique used to produce micron to submicron diameter polymeric fibers. Electrospun PVDF web was also evaluated for the sensing properties by micromechanical test and by measurement electrical resistance. CNT composite was especially prepared for high volume contents, 50 vol% of reinforcement. Electrical contact resistivity on humidity sensing was a good indicator for monitoring as for multifunctional applications. Work of adhesion using contact angle measurement was studied to correlate acid-base surface energy between carbon fiber and CNF composites, and will study furher for interfacial adhesion force by micromechanical test.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.20.2-20.2
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• 2010

Recently inkjet printing technology has been developed in the areas of low cost fabrication in environmentally friendly manufacturing processes. Although inkjet printing requires the interdisciplinary researches including development of materials, manufacturing processes and printing equipment and peripherals, manufacturing a printhead is still core of inkjet technology. In this study, a piezoelectric driven DOD (drop on demand) inkjet printhead has been fabricated on three layers of the silicon wafer in MEMS Technology because of its chemical resistance to industrial inks, strong mechanical properties and dimensional accuracy to meet the drop volume uniformity in printed electronics and display industries. The flow passage, filter and nozzles are precisely etched on the layers of the silicon wafers and assembled through silicon fusion bonding without additional adhesives. The piezoelectric is screen-printed on the top the pressure chamber and the nozzle plate surface is treated with non-wetting coating for jetting fluids. Printheads with nozzle number of 16 to 256 have been developed to get the drop volume range from 5 pL to 80 pL in various industrial applications. Currently our printheads are successfully utilized to fabricating color-filters and PI alignment layers in LCD Flat Panel Display and legend marking for PCB in Samsung Electronics.

• 한국구조물진단유지관리공학회 논문집
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• 제16권6호
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• pp.155-162
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• 2012

해수에 노출된 콘크리트 구조물은 시간의 경과에 따라 철근부식이 야기될 수 있으며, 이는 구조적인 성능저하로 진전된다. 1단계 연구에서 도출된 해수전착시스템의 개발을 통하여 2단계 연구에서는 해수전착 코팅된 철근 및 코팅철근을 사용한 RC 콘크리트 부재의 구조적, 내구적 성능이 평가되었다. 내구적 성능평가에서는 반전위 측정이 수행되었는데, 코팅된 철근은 일반철근의 35%수준의 부식속도를 가지고 있었으므로 높은 내부식성을 확보하고 있었다. 구조실험에서는 직접인장시험, 부착력시험, RC 부재를 이용한 휨 및 전단시험이 수행되었다. 인장강도 시험에서는 3.2%, 부착성능에서는 8.8%의 강도 증가가 코팅된 철근에서 평가되었다. RC보에 대한 실험에서는 최대하중 및 파괴형태는 두가지 경우에서 거의 동일하게 평가되었다. 해수전착된 시편은 철근주위에 콘크리트와 비슷한 화합물(수산화마그네슘, 탄산칼슘)이 형성되므로 부착력 및 강도를 일부 증가시키는 것으로 평가되었다. 해수전착철근은 피로, 내충격성, 장기침지실험 등을 통하여 성능이 입증되면 더욱 활발하게 사용될 것으로 사료된다.

• 한국구조물진단유지관리공학회 논문집
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• 제16권5호
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• pp.78-87
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• 2012

본 연구는 해수에 존재하는 다량의 칼슘 및 마그네슘 이온을 전기적으로 강판에 전착하는 전착시스템을 개발하는 것이다. 최종적인 목표는 해수를 이용하여 전착한 구조용 철근의 개발이며, 본 연구는 1단계 연구로서 고내구성 철근개발을 위한 전착시스템 개발에 목적을 두었다. 다양한 전극과 온도, 전류밀도, 코팅시간 등을 변수로 하고 실험을 수행하여 철근 코팅을 위한 최적의 조건을 도출하였다. 탄산칼슘($CaCO_3$)과 수산화마그네슘($Mg(OH)_2$)으로 구성된 코팅층은 SEM, EDS, XRD 등을 통하여 성분을 파악하였으며, 자연전위 및 전류밀도를 분석하여 기존의 철보다 부식에 대하여 매우 안전함을 확인하였다. 본 연구의 성과를 이용하여 고내구성 강재의 구조적, 내구적 실험에 대한 토의가 2차 연구에서 추가적으로 수행될 것이다.

• 상하수도학회지
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• 제33권2호
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• pp.111-119
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• 2019

Electro-coagulation process has been gained an attention recently because it could overcome the membrane fouling problems in MBR(Membrane bio-reactor). Effect of the key operational parameters in electro-coagulation, current density(${\rho}_i$) and contact time(t) on membrane fouling reduction was investigated in this study. A kinetic model for ${\rho}_i$ and t required to reduce the membrane fouling was suggested under different MLSS(mixed liquor suspended solids) concentration. Total 48 batch type experiments of electro-coagulations under different sets of current densities(2.5, 6, 12 and $24A/m^2$), contact times(0, 2, 6 and 12 hr) and MLSS concentration(4500, 6500 and 8500mg/L) were carried out. After each electro-coagulation under different conditions, a series of membrane filtration was performed to get information on how much of membrane fouling was reduced. The membrane fouling decreased as the ${\rho}_i$ and t increased but as MLSS decreased. Total fouling resistances, Rt (=Rc+Rf) were calculated and compared to those of the controls (Ro), which were obtained from the experiments without electro-coagulation. A kinetic approach for the fouling reduction rate (Rt/Ro) was carried out and three equations under different MLSS concentration were suggested: i) ${\rho}_i^{0.39}t=3.5$ (MLSS=4500 mg/L), ii) ${\rho}_i^{0.46}t=7.0$ (MLSS=6500 mg/L), iii) ${\rho}_i^{0.74}t=10.5$ (MLSS=8500 mg/L). These equations state that the product of ${\rho}_i$ and t needed to reduce the fouling in certain amounts (in this study, 10% of fouling reduction) is always constant.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.124.2-124.2
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• 2016

Corrosion resistance and adhesion of electro-paint (E-paint) with fluoride conversion coating (FCC) on AZ31 Mg alloy were studied. Corrosion resistance and adhesion were studied as a function of FCC-treatment time and concentration of FCC-bath. Aqueous hydrogen fluoride (HF) solutions, with concentrations ranging from 0.5 M to 5 M, were used to form FCC on chemically polished AZ31 Mg alloy samples for six different times; 10, 30, 60, 90, 120, and 180s. The results from salt spray test (SST) showed that corrosion resistance of E-paint appeared to decrease with increasing FCC treatment times in low concentration FCC baths. The number of blisters formed on the FCC-treated samples increased with increasing FCC treatment time of more than 1 min in low concentration (0.5 M to 1 M) solutions. On the other hand, samples treated in the 5 M HF solution for 120s showed no delamination or blistering even after 1200h of SST.

• 한국초전도ㆍ저온공학회논문지
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• 제5권2호
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• pp.1-7
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• 2003

Nowadays, one of the serious problems in KEPCO(Korea Electric Power Co-Operation) system is the more higher fault current than the SCC(Short Circuit Capacity) of circuit breaker. There are many alternatives to reduce the increased fault current such as isolations of bus ties, enhancement of SCC of circuit breaker, applications of HVDC-BTB(High Voltage Direct Current-Back to Back) and FCL(fault current limiter). But, these alternatives have some drawbacks in viewpoints of system stability and cost. As the superconductivity technology has been developed, the HTS-FCL(High Temperature Superconductor -Fault Current Limiter) can be one of the attractive alternatives to solve the fault current problem. Under this background, this paper presents the EMTDC(Electro-Magnetic Transient Direct Current) model for resistance type HTS-FCL considering the nonlinear characteristic of final resistance value when quenching phenomena occur.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 추계학술대회논문집
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• pp.224-227
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• 1997

In Ni and Zn plating, microstructure and corrosion behavior of electrodeposits with various electroplating condition were investigated. Optical microstructure, SEM images and polarization curves of electrodeposits are different with plating time and temperature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1821-1823
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• 1999

Carbon is an attractive material on electro double capacitor which depend on charge storage in the electrode/electrolyte interfacial double layer. Carbonaceous material for double layer capacitor can be obtained from carbon powder, fiber, film and porous carbon sheet. The capacitance of electrodes using an activated carbon was influenced by a filling density of the carbon, thickness and internal resistance of the electrode. In this study. to reduce internal resistance and increase electric conductivity of the electrode. activated carbon/carbon(AC/C) composite electrode was fabricated. The capacitors which have energy densities of 68F/g(at $30^{\circ}C$), 109F/g(at $60^{\circ}C$) and $68F/cm^3$(at $30^{\circ}C$), $111F/cm^3$(at $60^{\circ}C$) were fabricated by using AC/C composite electrodes.