• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.221-223
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• 1999

In this work, samples were manufactured variously by changing conventional calcining and sintering conditions and we tried the utilization by making the heat treatment time, which is demanded to high-Tc phase formation, much shorter. We found out optimal heat treatment conditions with the analysis on formation process at superconducting phase in term of the change of calcining and sintering time and then, examined X-ray diffraction(XRD) patterns, scanning electron microscope(SEM) measurement and energy dispersive X-ray spectrometer(EDX) of the samples manufactured under heat treatment conditions which we suggest here. As a result, 2223 high-$T_c$, phase of (Bi,Pb)SrCaCuO superconductor starting with ($Bi_l$ xPbx,)$_2$$Sr_2$$Ca_2$$Cu_3$$O_y$, composition was formed from 1 hr sintering sample at temperature nearby melting point and also the completed sample with calcining and sintering time of 9 hr was formed high-$T_c$.low-$T_c$ phase appearing in sight above the critical temperature of liquid $N_2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.576-577
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• 2005

In this paper, the oxidization characteristics were analyzed according to the shapes of Residual Current Protective Device(RCD) contacts. RCD is an electrical safety device specially designed to immediately switch the electricity off when electric leakage is detected at a level harmful to a person using electrical equipment. The shapes of RCD contacts are a little bit different according to the models. When RCD is turned on, stationary and moving contact do not fit together. So, it can cause the increase of contact resistance. To discover the deterioration characteristics of RCD contacts by switching repetition, the contacts were analyzed by stereo microscope, Scanning Electron Microscope(SEM) and Energy Dispersive X-ray Spectrometer(EDS).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.195.1-195.1
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• 2013

Cu는 금속 박막재료로서 높은 전기전도성을 지니고 있을 뿐만 아니라 Ag, Al, Pt 등 보다 비용이 저렴하여, 높은 전기전도성을 필요로 하는 박막 재료로써 폭넓게 사용되고 있다. 그러나, 낮은 기계적 특성을 지니고 있어서 interconnect와 같은 작은 단면적의 배선재료로 사용될 경우, 높은 전류밀도에 따른 electromigration 현상에 의하여 hillock 또는 void의 형성 등 박막재료의 변형이 생기게 되어서 전자소자의 수명이 단축된다는 단점이 있다. TiN은 금속재료 못지않은 높은 전기 전도성을 지니고 있을 뿐만 아니라, 금속재료에 비하여 높은 기계적 특성과 녹는점을 지니고 있어 다양한 분야로 사용되고 있다. 본 연구에서는 Cu와 TiN composite 박막을 soda-lime glass위에 증착하여 낮은 비저항 뿐만 아니라 Cu와 비교하여 기계적 특성이 향상된 박막을 제작하고자 하였다. Cu와 TiN composite 박막 증착을 위하여 DC reactive magnetron co-sputtering 장비를 사용하였으며, Cu와 Ti 타겟 power, Ar:N2 유량비(Flow rate)을 변화시켜 Cu와 Ti의 조성비 및 TiN의 결정성을 조절하였고, 이를 통하여 박막의 TiN 조성에 따른 낮은 비저항 값과 순수한 Cu 박막과 비교하여 높은 기계적 특성을 지닌 Cu-TiN 박막을 증착하였다. Cu-TiN composite 박막의 구조 및 조성은 SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectrometer), XPS (X-ray Photoelectron Spectroscopy)장비를 사용하여 분석하였으며, 전기전도도는 4-point probe를 사용하여 측정하였고, Knoop hardness 측정방법을 사용하여 박막의 기계적 특성을 측정하였다.

• 한국정밀공학회지
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• 제28권12호
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• pp.1419-1424
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• 2011

Nanoimprint lithography is a next generation lithography technology, which enables to fabricate nano to micron-scale patterns through simple and low cost process. Nanoimprint lithography has been applied in various industry fields such as light emitting diodes, solar cells and display. Functional patterns, including anti-reflection moth-eye pattern, photonic crystal pattern, fabricated by nanoimprint lithography are used to improve overall efficiency of devices in that fields. For these reasons, in this study, sub-micron-scaled functional patterns were directly fabricated on Si and glass substrates by thermal imprinting process using ZnO nano-particles dispersion resin. Through the thermal imprinting process, arrays of sub-micron-scaled pillar and hole patterns were successfully fabricated on the Si and glass substrates. And then, the topography, components and optical property of the imprinted ZnO nano-particles/resin patterns are characterized by Scanning Electron Microscope, Energy-dispersive X-ray spectroscopy and UV-vis spectrometer, respectively.

• Geomechanics and Engineering
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• 제21권4호
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• pp.337-348
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• 2020

Tropical organic soils having more than 65% of organic matters are named "peat". This soil type is extremely soft, unconsolidated, and possesses low shear strength and stiffness. Different conventional and industrial binders (e.g., lime or Portland cement) are used widely for stabilisation of organic soils. However, due to many factors affecting the behaviour of these soils (e.g., high moisture content, fewer mineral particles, and acidic media), the efficiency of the conventional binders is low and/or cost-intensive. This research investigates the impact of different constituents of cement-sodium silicate grout system on the compressibility behaviour of organic soil, including settlement and void ratio. A microstructure analysis is also carried out on treated organic soil using Scanning Electron Micrographs (SEM), Energy Dispersive X-ray spectrometer (EDX), and X-ray Diffraction (XRD). The results indicate that the settlement and void ratio of treated organic soils decrease gradually with the increase of cement and kaolinite contents, as well as sodium silicate until an optimum value of 2.5% of the wet soil weight. The microstructure analysis also demonstrates that with the increase of cement, kaolinite and sodium silicate, the void ratio and porosity of treated soil particles decrease, leading to an increase in the soil density by the hydration, pozzolanic, and polymerisation processes. This research contributes an extra useful knowledge to the stabilisation of organic soils and upgrading such problematic soils closer to the non-problematic soils for geotechnical applications such as deep mixing.

• Electronic Materials Letters
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• 제14권6호
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• pp.739-748
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• 2018

ZnS nanowalls, microspheres and rice-shaped nanoparticles have been successfully grown on graphene oxide (GO) sheets by the hydrothermal method. The morphologies, structures, chemical compositions and optical properties of the as-synthesized GO/ZnS have been characterized by X-ray power diffraction, energy dispersive spectrometer, scanning electron microscope, Raman spectra, photoluminescence spectroscopy and ultraviolet-visible absorption spectroscopy. It was found that the concentration of CTAB and the reaction temperature were important in the formation of GO/ZnS microstructures. The photocatalytic activity of the as-synthesized GO/ZnS was investigated through the photocatalytic degradation of textile dyeing waste. Results showed that the catalytic activity of the GO/ZnS porous spheres to methyl orange and methylene blue is higher than those of other samples. The degradation rates of methyl orange and methylene blue by porous spheres in 50 min were 97.6 and 97.1%, respectively. This is mainly attributed to the large specific surface area of GO/ZnS porous spheres and high separation efficiency between photogenerated electron and hole pairs.

• Corrosion Science and Technology
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• 제18권1호
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• pp.24-32
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• 2019

The effects of zinc coating and heat treatment on the corrosion resistance of aluminum alloys including A1100 and the modified A3003, used as heat exchanger tube were investigated in this study. The grain size of the heat-treated specimen is larger than that of the specimen without heat treatment, but the grain size did not significantly affect the corrosion behavior. The concentration of zinc was noted at 11.3 ~ 31.4 at.% for the as-received Zn-coated samples and reduced to 1.2 ~ 2.4 at.% after the heat treatment, as measured by the scanning electron microscopy (SEM) with an energy dispersive spectrometer (EDS) on the surface. The concentration of oxygen is 22 ~ 46 at.% for the zinc coated specimens while noted at 7.4 ~ 12.8 at.% for the specimens after the removal of the coating. The corrosion behavior depended largely on the concentrations of zinc, aluminum, and oxygen on the specimen surface, but not on the Mo content. The corrosion potential was high and the corrosion rate was low for a specimen with a low zinc content, a high aluminum content, and a high oxygen content.

• Journal of Electrochemical Science and Technology
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• 제10권3호
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• pp.257-270
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• 2019

The inhibition performance of sodium gluconate (SG), cetyltrimethylammonium bromide (CTAB) and their mixture (SG/CTAB) on the corrosion behavior of ${\alpha}$-brass in 0.5 M $H_2SO_4$ solution has been investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS), Inductively Coupled Plasma Spectrometry (ICPS) and molecular dynamics (MD) simulation techniques. The results reveal that SG with 5ppm CTAB, noted SG/CTAB, acts as a good corrosion inhibitor and its inhibition efficiency reached 89% after 24 h immersion in sulfuric acid solution, but slightly decreased at higher temperatures. The polarization curves displayed that SG/CTAB acts as a cathodic-kind inhibitor. Electrochemical impedance spectroscopy (EIS) studies revealed that the addition of 5ppm CTAB to different concentrations of SG considerably increases the corrosion resistance of ${\alpha}$-brass. The SEM-EDS and ICPS analyses support the experimental results. Further, molecular dynamics (MD) simulations were used to understand the adsorption profiles of SG/CTAB on Cu(111) and Zn(111) surfaces.

• 한국추진공학회지
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• 제23권2호
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• pp.46-52
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• 2019

케로신 연료의 침탄 특성에 대한 온도의 영향을 분석한 실험이 수행되었다. 케로신을 각각 600 K, 700 K, 800 K으로 가열한 후, 냉각시킨 시료를 채취하였다. 사용된 구리관은 온도조건에 따라 새로이 교체했다. 기체 크로마토그래피-질량분석과 에너지분산형 X선 분광기가 장착된 주사전자현미경을 통해 액체 시료와 구리 시편의 침탄 특성을 각각 분석하였다. 그 결과, 비교적 고온(800 K)으로 가열된 구리 시편의 내부표면에서 연료의 침탄으로 인해 침전물이 발생한 것을 확인하였다.

• 한국재료학회지
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• 제30권12호
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• pp.709-714
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• 2020

For zinc-air batteries, there are several limitations associated with zinc anodes. The self-discharge behavior of zinc-air batteries is a critical issue that is induced by corrosion reaction and hydrogen evolution reaction (HER) of zinc anodes. Aluminum and indium are effective additives for controlling the hydrogen evolution reaction as well as the corrosion reaction. To enhance the electrochemical performances of zinc-air batteries, mechanically alloyed Zn-Al and Zn-In materials with different compositions are successfully fabricated at 500rpm and 5h milling time. Investigated materials are characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), and energy dispersive spectrometer (EDS). Alloys are investigated for the application as novel anodes in zinc-air batteries. Especially, the material with 3 wt% of indium (ZI3) delivers 445.37 mAh/g and 408.52 mAh/g of specific discharge capacity with 1 h and 6 h storage, respectively. Also, it shows 91.72 % capacity retention and has the lowest value of corrosion current density among attempted materials.