• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.164-164
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• 2008

금속배선공정에서 높은 전도율과 재료의 값이 싸다는 이유로 최근 Cu를 사용하였으나, 디바이스의 구조적 특성을 유지하기 위해 높은 압력으로 인한 새로운 다공성 막(low-k)의 파괴와, 디싱과 에로젼 현상으로 인한 문제점이 발생하게 되었다. 이러한 문제점을 해결하고자, 본 논문에서는 Cu 표면에 Passivation layer를 형성 및 제거하는 개념으로 공정시 연마제를 사용하지 않으며, 낮은 압력조건에서 공정을 수행하기 위해, 전해질의 농도 변화에 따른 Liner sweep voltammetry 법을 사용하여 전압활성화에 의한 전기화학적 반응이 Cu전극에 어떤 영향을 미치는지 연구하였으며, 표면 조성을 알아보기 위하여 Energy Dispersive Spectroscopy (EDS) 분석을 하였고, Cu disk의 결정성과 배향성 관찰을 위해 X-Ray diffraction (XRD)로 금속 표면을 비교하여 실험 결과로 얻어진 데이터를 통하여 ECMP 공정에 적합한 전해액 선정과 농도를 선택하였다.

• Journal of Conservation Science
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• v.35 no.4
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• pp.373-383
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• 2019

We characterized the smelting process and smelting furnace through scanning electron microscopy-energy dispersive spectroscopy, wavelength dispersive X-ray fluorescence, X-ray diffraction, and raman micro-spectroscopy with 13 relics including slags and furnace walls excavated from square-shaped building sites and pits of the Three Kingdoms site at the Ungyo site section I. Our results revealed that the principal components were FeO and SiO₂; and CuO, PbO, and ZnO were contained in small quantities. Furthermore, fayalite, magnetite, augite, copper, and cuprite were found. High contents of FeO or SiO₂ components seem to have been added to form fayalite to remove gangue in the smelting process. The relatively low content of S detected in the copper prills suggests that roasting was performed well. Cristobalite and mullite, which are minerals that indicate high-temperature found in the furnace wall, show that the smelting temperature was higher than 1,250℃. The findings of this study show a high possibility that the Wanju Ungyo site is smelting remains of copper ores, which are nonferrous metals, rather than iron. Various smelting byproducts excavated in this area in the future will help us better understand the copper smelting process that may have been performed since ancient times.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2088-2092
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• 2011

The accelerated thermal aging of CSPE(chloro sulfonate polyethylene) of test cables were carried out for the period equal to 10, 20 and 30 years in air at $100^{\circ}C$, respectively. The CSPE cables(TAIHAN electric wire Co. Ltd) which installed in nuclear power plant for three years were used as starting materials. Condition monitering methods of the accelerated thermal aging of CSPE cables were estimated through indenter modulus and OIT(oxidation induction time) of IEC 62582, and those were newly estimated through volume electrical resistivity, ultrasound reflection time, density, FE-SEM(field emission scanning electron microscopy), XPS(x-ray photoelectron spectroscopy), EDS(energy dispersive spectroscopy), and WD-XRF(wavelength dispersive x-ray fluorescence). A new condition monitoring methods of the accelerated thermal aging of CSPE cables were generally coincident with trend of indenter modulus expect EDS, XPS and XRF. A volume electrical resistivity among new condition monitoring methods of the accelerated thermal aging of CSPE cables is excellent. It is considered that life-time of CSPE cable can be predicted through volume electrical resistivity, if CSPE jacket was aged for period such as more than 20 years.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1309-1311
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• 1998

$Pb_{1-x}La_xTi_{1-x/4}O_3$ (PLT(x)) thin film has been regarded as one of the most promising materials for applications of sensor, optic devices, and memory devices, because it exhibits various properties as changing the amount of Lanthanum component. So we have prepared PLT thin films on platinized silicon (actually Pt/Ti/$SiO_2$/Si) substrates in oxygen ambient by laser ablation. Energy dispersive X-ray (EDX) revealed that the stoichiometric thin films were fabricated.

• Journal of Korea Foresty Energy
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• v.21 no.3
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• pp.18-27
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• 2002

Pine bark was liquefied in the presence of phenol using organic sulfonic acids as catalysts, and the liquefied barks were characterized. It was found that the organic sulfonic acids were more effective catalysts than hydrochloric acid for complete liquefaction of pine bark. The liquefied barks prepared from phenol-organic sulfonic acid liquefaction were highly phenolated, and the amounts of combined phenol were 2-3 times greater than that of the liquefied bark obtained from phenol-hydrochloric acid liquefaction. The glass transition points (Tg) were lower than that of the liquefied barks prepared from phenol-hydrochloric acid. It can be concluded that by using the organic sulfonic acids, the phenol used as a liquefying reagent is highly introduced into the bark, resulting in the phenolated bark preventing further condensation reactions, which may occur during the liquefaction. The carbohydrates such as cellulose and hemicellulose in the liquefied barks were almost decomposed during the liquefaction, from the results of IR spectra and neutral sugar analyses. Energy dispersive X-ray spectromery (EDS) results from the residues and the liquefied barks showed that the organic sulfonic acid catalysts did not lead to serious corrosion of the reactor compared with the hydrochloric acid catalyst.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1252-1254
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• 1997

Direct methanol fuel cell based on a proton-exchange membrane electrolyte was investigated. 60% Pt-Ru/C and 60%Pt/C catalysts were employed for methanol oxidation and oxygen reduction, respectively. Morphologies of the catalysts were investigated by x-ray power diffraction, energy dispersive x-ray spectroscopy, and transmission microscopy. Electrochemical characteristics of the catalysts were tested by using cyclic voltametry technique. I-V characteristics of the fuel cell were tested by changing methanol concentration, temperature, and Nafion type as a proton-exchange membrane electrolyte. AC impedance technique was used to investigate the electrochemical performance of the fuel cell. The performance of single cell was enhance with increasing cell temperature. High operation temperature attributed to the combined effects of the reduction of ohmic resistance and polarization. High cell voltage was obtained from the concentration of 205M methanol. With Nafion 112, a current density of $230mA/cm^2$ at 0.55V was obtained from the concentration of 2.5M methanol.

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.125-129
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• 2020

In this study we developed a method for determining the geographic origin of soybeans by combining energy dispersive X-ray fluorescence spectrometry with statistical analysis. In 2018, 197 soybean samples (100 Korean domestic samples and 97 foreign samples) were collected for the construction of a geographic origin model. The mineral concentrations of 26 elements were measured and determined via the fundamental parameters approach. One-way analysis of variance, t-test, and canonical discriminant analysis were employed to reveal five elements (P, Ni, Br, Zn, and Mn) that could be used for the determination of geographic origins. The sensitivity, specificity, and efficiency for the above method were 91.0, 95.9, and 93.4%, respectively. Validation results from 60 samples collected in 2019 showed a predictive rate of 93.3% for Korean domestic soybeans and 100.0% for foreign soybeans. In conclusion, the combination of energy dispersive X-ray fluorescence spectrometry and chemometrics could be used to effectively determine the geographic origin of soybeans.

• Journal of Powder Materials
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• v.20 no.1
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• pp.53-59
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• 2013

Fe-TiC composite powder was fabricated via two steps. The first step was a high-energy milling of FeO and carbon powders followed by heat treatment for reduction to obtain a (Fe+C) powder mixture. The optimal condition for high-energy milling was 500 rpm for 1h, which had been determined by a series of preliminary experiment. Reduction heat-treatment was carried out at $900^{\circ}C$ for 1h in flowing argon gas atmosphere. Reduced powder mixture was investigated by X-ray Diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM) and Laser Particle Size Analyser (LPSA). The second step was a high-energy milling of (Fe+C) powder mixture and additional $TiH_2$ powder, and subsequent in-situ synthesis of TiC particulate in Fe matrix through a reaction of carbon and Ti. High-energy milling was carried out at 500 rpm for 1 h. Heat treatment for reaction synthesis was carried out at $1000{\sim}1200^{\circ}C$ for 1 h in flowing argon gas atmosphere. X-ray diffraction (XRD) results of the fabricated Fe-TiC composite powder showed that only TiC and Fe phases exist. Results from FE-SEM observation and Energy-Dispersive X-ray Spectros-copy (EDS) revealed that TiC phase exists uniformly dispersed in the Fe matrix in a form of particulate with a size of submicron.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.423-423
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• 2008

One dimensional (1D) nanostructures, including nanowires, nanorods, nanobelts, and nanotubes, have been the focus of current research on nanotechnology because of their fundamental significance in chemistry, physics, materials science and engineering, and potential applications in nanoelectronics. We have synthesized Te-rich $Sb_xTe_{1-x}$ nanowires and nanotubes via thermal evaporation method under vapor-solid mechanism. The physical morphology and chemical composition of the fabricated nanowires and nanotubes were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX).

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3051-3058
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• 2022

In the present work, untreated Iraqi sand with grain sizes varied between 100 and 200 ㎛ was used to produce a colored glass sample that has shielding features against the low gamma-ray energy. Therefore, a weight of 70-60 wt % sand was mixed with 9-14 wt% B₂O₃, 8-10 wt% Na₂O, 4-6 wt% of CaO, 3-6 wt% Al₂O₃, in addition to 0.3% of Co₂O₃. After melting and annealing the glass sample, the X-ray diffraction spectrometry was applied to affirm the amorphous phase of the fabricated glass samples. Moreover, the X-ray dispersive energy spectrometry was used to measure the chemical composition, and the MH-300A densimeter was applied to measure the fabricated sample's density. The Makishima-Makinzie model was applied to predict the mechanical properties of the fabricated glass. Besides, the Monte Carlo simulation was used to estimate the fabricated glass sample's radiation shielding capacity in the low-energy region between 22.1 and 160.6 keV. Therefore, the simulated linear attenuation coefficient changed between 10.725 and 0.484 cm^-1, raising the gamma-ray energy between 22.1 and 160.6 keV. Also, other shielding parameters such as a half-value layer, pure lead equivalent thickness, and buildup factors were calculated.