• Journal of Hydrogen and New Energy
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• v.29 no.3
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• pp.243-250
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• 2018

Zinc oxide (ZnO) nanorods were grown on a palladium (Pd) activated polyacrylonitrile (PAN) fiber where Pd activation was carried out in advance by the following dry process: palladium(II) bis(acetylacetonate), $Pd(acac)_2$ was sublimed, penetrated into the surface of PAN fiber and spontaneously reduced to Pd nanoparticles at $180^{\circ}C$ for various times under a nitrogen atmosphere. ZnO nanorod morphology was observed by a scanning electron microscopy (SEM) and the elemental composition was confirmed by energy-dispersive X-ray spectroscopy (EDS). The crystalline structure of ZnO nanorods was analyzed by X-ray diffraction (XRD) analysis showing Wurtzite structure consisting of hexagonal lattice. Sulfur removal characteristics were evaluated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.49-49
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• 2007

최근 반도체 소자의 고집적화와 나노 (nano) 크기의 회로 선폭으로 인해 기존에 사용되었던 텅스텐이나 알루미늄 금속배선보다, 낮은 전기저항과 높은 electro-migration resistance가 필요한 Cu 금속배선이 주목받게 되었다. 하지만, Cu CMP 공정 시 높은 압력으로 인하여 low-k 유전체막의 손상과 디싱과 에로젼 현상으로 인한 문제점이 발생하게 되었다. 본 논문에서는, $KNO_3$ 전해액의 농도가 Cu 표면에 미치는 영향을 알아보기 위해 Tafel Curve와 CV (cyclic voltammograms)법을 사용하여 전기화학적 특징을 알아보았고 scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray Diffraction (XRD) 분석을 통해 금속표면을 비교 분석하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.81-81
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• 2007

Chemical mechanical polishing (CMP) 공정은 deep 서브마이크론 집적회로의 다층배선구조률 실현하기 위해 inter-metal dielectric (IMD), inter-layer dielectric layers (ILD), pre-metal dielectric (PMD) 층과 같은 절연막 외에도 W, Al, Cu와 같은 금속층을 평탄화 하는데 효과적으로 사용되고 있으며, 다양한 소자 제작 및 새로운 물질 등에도 광범위하게 응용되고 있다. 하지만 Cu damascene 구조 제작으로 인한 CMP 응용 과정에서, 기계적으로 깨지기 쉬운 65 nm의 소자 이하의 구조에서 새로운 저유전상수인 low-k 물질의 도입으로 인해 낮은 하력의 기계적 연마가 필요하게 되었다. 본 논문에서는 전기화학적 기계적 연마 적용을 위해, I-V 특성 곡선을 이용하여 active, passive, transient, trans-passive 영역의 전기화학적 특성을 알아보았으며, Cu 막의 표면 형상을 알아보기 위해 scanning electron microscopy (SEM) 측정과 energy dispersive spectroscopy (EDS) 분석을 통해 금속 화학적 조성을 조사하였다.

• Journal of Welding and Joining
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• v.25 no.6
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• pp.78-83
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• 2007

The wettability of Sn-Xwt%Cu(X=$0{\sim}3wt%$) solder was evaluated with wetting balance tester. And, the intermetallic compounds(IMCs) which were formed at the interface between solders and pads were investigated by using scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The wetting force of Sn-0.7wt%Cu solder was higher than that of 100wt%Sn and Sn-3.0wt%Cu solder. The value of $\gamma_{fl}$ and ($\gamma_{fs}-\gamma_{ls}$) had a tendency to increase with increasing the wetting temperature. The activation energy with bare Cu pad and flux with 15% solid content was increased in the following order: Sn-0.7Cu (68.42 kJ/mol) ; Sn-3.0Cu(72.66 kJ/mol) ; Sn solder(94.53 kJ/mol). It was identified that the Cu6Sn5 phase was formed at the interface between Sn-Xwt%Cu solder and Cu pad.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.156-168
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• 2023

This study investigates the high temperature oxidation behaviour of a Ni-20Cr-1.2Si (wt.%) alloy in steam from 1200 ℃ to 1350 ℃ by Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). The results demonstrate that exposed Ni-based alloy developed a thin oxide scale, consisted mainly of Cr₂O₃. The oxidation kinetics obtained from the experimental results was applied to evaluate the hydrogen generation considering a simplified reactor core model with different cladding alloys following an unmitigated Loss-Of-Coolant Accident (LOCA) scenario in a hypothetical Small Modular Reactor (SMR). Overall, experimental data and simulations results show that both Fe-based and Ni-based alloys may enhance cladding survivability, delaying its melting, as well as reducing hydrogen generation under accident conditions compared to Zr-based alloys. However, a substantial neutron absorption occurs when Ni-based alloys are used as cladding for current uranium-dioxide fuel systems, even when compared to Fe-based alloys.

• Carbon letters
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• v.22
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• pp.48-59
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• 2017

This study synthesized pure anatase carbon doped $TiO_2$ photocatalysts supported on a stainless steel mesh using a sol-gel solution of 8% polyacrylonitrile (PAN)/dimethylformamide (DMF)/$TiCl_4$. The influence of the pyrolysis temperature and holding time on the morphological characteristics, particle sizes and surface area of the prepared catalyst was investigated. The prepared catalysts were characterized by several analytical methods: high resolution scanning electron microscopy (HRSEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). The XRD patterns showed that the supported $TiO_2$ nanocrystals are typically anatase, polycrystalline and body-centered tetragonal in structure. The EDS and XPS results complemented one another and confirmed the presence of carbon species in or on the $TiO_2$ layer, and the XPS data suggested the substitution of titanium in $TiO_2$ by carbon. Instead of using calcination, PAN pyrolysis was used to control the carbon content, and the mesoporosity was tailored by the applied temperature. The supported $TiO_2$ nanocrystals prepared by pyrolysis at 300, 350, and $400^{\circ}C$ for 3 h on a stainless steel mesh were actual supported carbon doped $TiO_2$ nanocrystals. Thus, $PAN/DMF/TiCl_4$ offers a facile, robust sol-gel related route for preparing supported carbon doped $TiO_2$ nanocomposites.

• Conservation Science in Museum
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• v.9
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• pp.1-15
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• 2008

We observed the section and microstructure by Scanning Electron Mirrorscope (SEM) for 4 'Bowls, white porcelain with impressed floral design and sliver bound rim' and 1 'Dish, white porcelain with sliver bound rim', which was manufactured by reverse firing and metal bound rim was wrapped to the part of not being spread glaze at inlet, in Jingdezhen white porcelains, the relics dug from the seabed of Shinan conserved in National Museum of Korea, and found that the ingredient of metal rim was not silver but tin as a result of measuring by BEI of Energy Dispersive Spectroscopy (EDS). And as a result of survey with Fourier transform infrared spectroscopy(FT-IR) for checking the method of joining metal rim of mouth part, it was found that joining was made with materials made of lacquer.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1061-1068
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• 2010

The biological synthesis of nanoparticles has gained considerable attention in view of their excellent biocompatibility and low toxicity. We isolated and purified rhamnolipids from Pseudomonas aeruginosa strain BS-161R, and these purified rhamnolipids were used to synthesize silver nanoparticles. The purified rhamnolipids were further characterized and the structure was elucidated based on one- and two-dimensional $^1H$ and $^{13}C$ NMR, FT-IR, and HR-MS spectral data. Purified rhamnolipids in a pseudoternary system of n-heptane and water system along with n-butanol as a cosurfactant were added to the aqueous solutions of silver nitrate and sodium borohydride to form reverse micelles. When these micelles were mixed, they resulted in the rapid formation of silver nanoparticles. The synthesized nanoparticles were characterized by UV-Visible spectroscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy (EDS). The nanoparticles formed had a sharp adsorption peak at 410 nm, which is characteristic of surface plasmon resonance of the silver nanoparticles. The nanoparticles were monodispersed, with an average particle size of 15.1 nm (${\sigma}={\pm}5.82$ nm), and spherical in shape. The EDS analysis revealed the presence of elemental silver signal in the synthesized nanoparticles. The formed silver nanoparticles exhibited good antibiotic activity against both Grampositive and Gram-negative pathogens and Candida albicans, suggesting their broad-spectrum antimicrobial activity.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.381-387
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• 2018

Our study focuses on upgrading real biogas obtained under Indian scenario using carbon capture and utilization (CCU) technology to remove carbon dioxide ($CO_2$) and utilize it by forming metal carbonate. Amines such as monoethanolamine (MEA), diethanolamine (DEA), and sodium hydroxide (NaOH) were used to rapidly convert gaseous $CO_2$ to aqueous $CO_2$, and $BaCl_2$ was used as an additive to react with the aqueous $CO_2$ and rapidly precipitating the aqueous $CO_2$. All experiments were conducted at $25^{\circ}C$ and 1 atm. We analyzed the characteristics of the $BaCO_3$ precipitates using X-ray diffractometry (XRD), scanning electron microscopy - Energy dispersive spectroscopy (SEM-EDS) and Fourier-transform infrared spectroscopy (FT-IR) analyses. The precipitates exhibited witherite morphology confirmed by the XRD results, and FT-IR confirmed that the metal salt formed was $BaCO_3$, and EDS showed that there were no traces of impurities present in it. The quantity of the $BaCO_3$ was larger when formed with DEA. Also, a comparison was done with a previous study of ours conducted in Korean conditions. Finally, we observed that the carbonate obtained using real biogas showed similar properties to carbonates available in the market. An economic analysis was done to show the cost effectiveness of the method employed by us.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.92-100
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• 2014

Hydrophobic magnesium hydroxide [$Mg(OH)_2$] was modified by hydrothermal method using non-ionic sorbitol surfactant with Span series. Mganesium chloride [$MgCl_2$] and sodium hydroxide [NaOH] were used for synthesis of $Mg(OH)_2$. Also non-ionic surfactant were added as a stabilizer, dispersant and surface modifier. Addition of non-ionic surfactant was favourable to obtain small sized $Mg(OH)_2$ particles with better dispersibility and hydrophobic property of $Mg(OH)_2$ particles. The obtained product were characterized by particle size analysis(PSA), scanning electron microscope(SEM), energy dispersive spectroscopy(EDS), x-ray diffraction(XRD) and fourier transform infrared spectroscopy(FT-IR). The results show that the product are prepared with this method has a well hydrophobic properties and dispersity compared with unmodified $Mg(OH)_2$ particles. The improve properties of surface modified $Mg(OH)_2$ particles were also verified by similarity synthesizing under slightly different conditions.