Institute for Advanced Engineering IAE

Yongin Si, South Korea

Institute for Advanced Engineering IAE

Yongin Si, South Korea
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Choi J.,Dankook University | Joo S.,Institute for Advanced Engineering IAE | Park T.J.,Hanyang University | Kim W.-B.,Dankook University
Applied Surface Science | Year: 2017

Low-temperature nitric acid (HNO3) oxidation of Si (NAOS) has been used to improve the interface and electrical properties of ∼5 nm-thick SiO2/Si layers produced by plasma-enhanced chemical vapor deposition (PECVD). Investigations of the physical properties and electrical characteristics of these thin films revealed that although their thickness is not changed by NAOS, the leakage current density at a gate bias voltage of −1 V decreases by about two orders of magnitude from 1.868 × 10−5 A/cm2. This leakage current density was further reduced by post-metallization annealing (PMA) at 250 °C for 10 min in a 5 vol.% hydrogen atmosphere, eventually reaching a level (5.2 × 10−8 A/cm2) approximately three orders of magnitude less than the as-grown SiO2 layer. This improvement is attributed to a decrease in the concentration of suboxide species (Si1+, Si2+ and Si3+) in the SiO2/Si interface, as well as a decrease in the equilibrium density of defect sites (Nd) and fixed charge density (Nf). The barrier height (Фt) generated by a Poole-Frenkel mechanism also increased from 0.205 to 0.371 eV after NAOS and PMA. The decrease in leakage current density is therefore attributed to a densification of the SiO2 layer in combination with the removal of OH species and increase in interfacial properties at the SiO2/Si interface. © 2017 Elsevier B.V.

Park S.H.,Institute for Advanced Engineering IAE | Lee S.J.,Institute for Advanced Engineering IAE | Lee J.W.,Institute for Advanced Engineering IAE | Chun S.N.,Technology Commercialization Office | Lee J.B.,Technology Commercialization Office
Energy | Year: 2015

Integrated Gasification Combined Cycle technology with Carbon Capture Storage has many potentialadvantages for future power generation system and many pre-combustion CO2 capture technologies have been developed for removing the acid gas and CO2 from the syngas. In this study, redesign and modeling of the two-stage pre-combustion CO2 capture process, using three different physical solvents, was conducted. The quantitative design modeling analysis was performed using the computational software ASPEN Plus®. The Selexol process was evaluated as the most efficient pre-combustion CO2 capture process from the points of electric/thermal energy consumption as a result of ASPEN Plus® modeling. The Selexol modeling process resulted in electric energy of about 3.2 MWe to maintain the operating temperature and pressure by using the pump, the compressor and the chiller. The consumption of thermal energy was also evaluated to be 0.85MWth for regeneration of the solvent in the H2S stripper. Concomitantly, various comparison and performance results were obtained by changing the key design modeling parameters; Water-Gas Shift conversion rate, operating temperature and CO2 capture rate were varied for their individual effects on energy consumption, solvent and hydrogen loss. As Water-Gas Shift conversion rate increased, the Selexol process consumes the least amount of electric energy among the modeled CO2 capture processes using the physical solvents. On the other hand, changing the operating temperature turned out to be advantageous for the Rectisol process over other CO2 capture processes using the physical solvents. The reboiler heat duty and hydrogen loss with total solvent flow rate can also be reduced by dropping the operating temperature. As CO2 capture rate increased, Selexol process was more efficient than other processes using the Methanol and NMP (NMethyl- 2-Pyrrolidone). This modeling result is explained by the decrease in the reboiler heat duty and electrical energy consumption although the solvent flow rate increased. © 2014 Elsevier Ltd. All rights reserved.

Lee C.-H.,Kongju National University | Jeong M.-K.,Kongju National University | Fatih Kilicaslan M.,Kastamonu University | Lee J.-H.,Chungnam National University | And 2 more authors.
Waste Management | Year: 2013

In this study, a method which is environmentally sound, time and energy efficient has been used for recovery of indium from used liquid crystal display (LCD) panels. In this method, indium tin oxide (ITO) glass was crushed to micron size particles in seconds via high energy ball milling (HEBM). The parameters affecting the amount of dissolved indium such as milling time, particle size, effect time of acid solution, amount of HCl in the acid solution were tried to be optimized. The results show that by crushing ITO glass to micron size particles by HEBM, it is possible to extract higher amount of indium at room temperature than that by conventional methods using only conventional shredding machines. In this study, 86% of indium which exists in raw materials was recovered about in a very short time. © 2012 Elsevier Ltd.

Kang S.-H.,Institute for Advanced Engineering IAE | Bae J.W.,Korea Research Institute of Chemical Technology | Bae J.W.,Sungkyunkwan University | Cheon J.-Y.,Korea Research Institute of Chemical Technology | And 5 more authors.
Applied Catalysis B: Environmental | Year: 2011

Fischer-Tropsch synthesis (FTS) for the co-production of C2-C4 olefins and clean fuels such as gasoline and middle distillate from syngas was investigated on four different iron-based catalysts in a fixed-bed and a bubbling fluidized-bed reactor. The catalysts were prepared by wet-impregnation using the Al2O3, SiO2 and iron ore (FeOx) supports with the active components of Fe, K and (or) Cu, and each K/FeCuAlOx catalyst was prepared by a co-precipitation method. Except for the catalyst impregnated on SiO2, CO conversion of the other catalysts is similar regardless of the type of reactor. However, the yield of light olefins in the range of C2-C4 hydrocarbons and clean fuels is closely related to the formation of active iron carbide species and to surface acidity. The impregnated K/FeOx catalyst is found to be one of the promising catalysts to be applied in a bubbling fluidized-bed reactor for middle temperature FTS reaction due to its high resistance to catalyst attrition with a high catalytic performance. © 2011 Elsevier B.V.

Hong H.S.,Institute for Advanced Engineering IAE | Jung H.,Institute for Advanced Engineering IAE | Hong S.-J.,Kongju National University
Research on Chemical Intermediates | Year: 2010

Indium components have been successfully recovered from indiumcontaining scrap powders collected by the sand-blasting of sputtering chamber walls. A two-step air-classifier was used for the classification of the scrap powder. The raw scrap powders containing 10 wt% indium were classified into 12 lots according to the revolutions per minute of a classifying wheel: 6,000, 8,000, 10,000, and 12,000 rpm. The enrichment of indium component was possible in fine overflow fraction, that is, the third classified fractions at all wheel speeds, while the indium components were not concentrated in the first classified fraction. The grade of the indium components became higher with decreasing particle size and the highest grade was obtained in the third classified fraction. The purity of the indium component improved to 17.4 wt% and the recovery of the indium component was in the range 94.2-96.2% for the second and third classified fractions. The recovery and enrichment of indium should be optimized for the maximum recycling of the indium components, which can be used as raw materials in the subsequent electro-refining processes. © Springer Science+Business Media B.V. 2010.

Jeong D.-W.,Yonsei University | Subramanian V.,Yonsei University | Shim J.-O.,Yonsei University | Jang W.-J.,Yonsei University | And 4 more authors.
Catalysis Letters | Year: 2013

Simulated waste-derived synthesis gas has been tested for hydrogen production through water gas shift (WGS) reaction in the temperature range of 350-550 C over chromium free Fe/Al/Cu oxide based catalysts. The CuO loading amount was optimized to get highly active Fe/Al/Cu oxide based catalysts for the high temperature WGS. Despite the high CO content in the feed gas (38.2 % dry basis), 15 % CuO catalyst exhibited the highest CO conversion (86 %) and 100 % selectivity to CO2 at a very high gas hourly space velocity (GHSV) of 40,057 h-1 due to easier reducibility, the synergy effect of copper and aluminum, and the stability of the active phase (magnetite: Fe 3O4). Graphical Abstract: [Figure not available: see fulltext.] © 2013 Springer Science+Business Media New York.

Swain B.,Institute for Advanced Engineering IAE | Mishra C.,Institute for Advanced Engineering IAE | Hong H.S.,University of Seoul | Cho S.-S.,Institute for Advanced Engineering IAE | Lee S.K.,Institute for Advanced Engineering IAE
Green Chemistry | Year: 2015

A commercial process for the recovery of metals from the indium-tin-oxide (ITO) etching industry wastewater by liquid-liquid extraction has been developed. A suitable cross current simulated batch process was developed, and extraction mechanisms involved in the process were analyzed. Mathematical models were proposed to correlate metal extractability with respect to extractant concentrations and metal loading with respect to the solvent/solution volume ratio. Optimum conditions required for the complete scrubbing of Mo and Sn using Cyanex 272 and quantitative extraction of pure In using DP-8R were estimated by a proposed model. A good agreement between the proposed model and the observed results was found. Based on the laboratory scale simulation, a pilot plant batch process was developed and simulated. The developed process is a techno-economically feasible, environmentally friendly, occupationally safe, and clean and green process for the commercial treatment of ITO etching industry wastewater and recovery of valuable metals through liquid-liquid extraction. In with 99.999% purity, Cu nanopowder with 99.999% purity, Mo and Sn with 99% purity were recovered. © The Royal Society of Chemistry 2015.

Kang S.-H.,Korea Research Institute of Chemical Technology | Kang S.-H.,Institute for Advanced Engineering IAE | Bae J.W.,Korea Research Institute of Chemical Technology | Kim H.-S.,Korea Research Institute of Chemical Technology | And 2 more authors.
Energy and Fuels | Year: 2010

Direct synthesis of dimethyl ether (DME) from synthesis gas was investigated on bifunctional catalysts, containing Cu-ZnO-Al2O 3 promoted with Zr or Ga on γ-Al2O3 as a methanol dehydration catalyst. In comparison to an unpromoted bifunctional catalyst, promoted catalysts with Zr or Ga showed a higher catalytic performance and stability. The facile reducibility of copper particles with high dispersion and an appropriate acidity and electronic state of copper species are mainly responsible for the superior catalytic performance with the help of structural promoting effects of Ga or Zr components on Cu-ZnO-Al2O3. The high formation rate of methanol by CO hydrogenation on the Zr-promoted Cu-ZnO-Al2O3 and the dehydration rate of methanol to DME on the modified acidic sites of γ-Al2O3 are mainly responsible for the superior catalytic activity and stability. Copyrigh © 2009 American Chemical Society.

Kim S.,Hanyang University | Lee Y.-I.,Hanyang University | Kim D.-H.,Hanyang University | Lee K.-J.,Institute for Advanced Engineering IAE | And 3 more authors.
Carbon | Year: 2013

Chemical functionalization of multi-walled carbon nanotubes (MWCNTs) was carried out by UV/ozone treatment. MWCNTs were characterized by elemental analysis, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) before and after treatment. The dispersion stability was investigated using UV-vis spectroscopy and a dispersion stability analyzer. Results confirmed the presence of oxygen-containing groups on the MWCNT surfaces by UV/ozone treatment resulting in dispersion stability better than for pristine MWCNTs in polar solvents. A simple method described to investigate the solubility behavior of MWCNTs functionalized with UV/ozone treatment in various organic solvents. To illustrate this concept, CNT dispersions were prepared using UV/ozone treatment with controlled times, and their solubility behavior was represented on three-dimensional graphs using Hansen solubility parameters. Based on these solubility data, a MWCNT/PMMA composite was prepared using an appropriate solvent and the sheet resistance was measured using a four-point probe method. As a result, composites made with MWCNTs having undergone UV/ozone treatment showed lower sheet resistance than CNT composites made from pristine or acid-treated MWCNTs. © 2012 Published by Elsevier Ltd.

Lee K.-J.,Institute for Advanced Engineering IAE | Kang L.-S.,Institute for Advanced Engineering IAE | Uhm S.,Institute for Advanced Engineering IAE | Yoon J.S.,Korea Basic Science Institute | And 2 more authors.
Current Applied Physics | Year: 2013

LiMnBO3 with enhanced powder density was successfully synthesized by a commercially available spray-drying process. A monoclinic-LiMnBO3 single phase was experimentally substantiated by an X-ray diffractometer with crystallinity investigated by Rietveld refinement method (Bragg R-factor and RF-factor <10). The dense LiMnBO3 powder prepared by the spray drying process showed spherical morphology. The electrochemical property of LiMnBO3 was extensively investigated, positively revealing that 0.27 Li+ (Li0.27MnBO 3) was stoichiometrically extracted from the host LiMnBO3 material at first cycle. © 2013 Elsevier B.V. All rights reserved.

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