• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.2
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• pp.38-45
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• 1997

In this paper, the three-dimensional stress effect of thermal oxide is simulated. We developed a three-dimensional finite element numerical simulator including three-dimensional adaptive mesh generator that is able to refine and eliminate nearby moving boundary of oxide, and oxidation solver with stress model. To investigate the behavior of thermal oxidation the simulations of thermal oxidation for island and hole structures are carried out assuming silicon wafer of <100> direction, temperature of $1000^{\circ}C$, oxidation time of 60min, wet ambient, initial oxide thickness of $300\AA$, and nitride thickness of $2, 000\AA$. The main effect of deformation at the corner area of oxide is due to distribution of oxidant, but the deformation of oxide is affected by the stressin theoxide. In the island structure which is the structure mostly covered with nitride and a coner is opended to oxidation, oxidation is reduced at the coner by compressive stress. In the hole structure which is the structure mostly opedned to oxide and a coner is convered with nitride, however, oxidation is increased at the coner by tensile stress.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.56-59
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• 2000

In this paper, we have made a comparison between secondary ion mass spectroscopy(SIMS) data by the 5kcV-15keV boron implantation and computer simulation results. In order to make electrical activation of implanted carriers, thermal annealing are carried out by RTP method for 30s at 1000$^{\circ}C$ Two dimensional doping concentration distribution from different mask dimensions under inert gas annealing, dry-, and wet-oxidation condition were calculated and simulated with microtec simulator.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.3
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• pp.11-18
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• 2013

Interest in copper nanoparticles has increased as an alternative for substituting silver nanoparticles because of its lower cost and less electromigration effect than silver. In this paper, the recent research trends and main results in wet-chemical synthesis of sub-100 nm Cu nanoparticles were summarized. The characteristics of synthesis were discussed with a classification such as modified polyol synthesis, modified hydrothermal synthesis, solvothermal synthesis, and the others, focussing on effects of capping agents, reductants, and pH. Information on the oxidation of synthesized copper nanoparticles were additionally commented.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.2
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• pp.101-108
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• 2008

This study attempted to develop the technology by gaseous ozone for decontaminating building affected by a model of biological weapon agent(Bacillus subtilis spores) instead of Bacillus anthracis spore. The use of ozone is attractive method from a practical point of view of decontamination procedure since it has strong oxidation power but no residue after application. We examined the disinfection efficiency of gaseous ozone to Bacillus subtilis spores which suspension was sprayed on different material surfaces and dried. Three different types of gaseous ozone was applied : dry ozone, dry ozone with humidified air, and water bubbled wet ozone. Dry ozone(1500ppm) failed to achieve any significant inactivation for 2hrs. However, six log reduction of B. subtilis spore was achieved within 30min by 1500ppm of water bubbled wet ozone. This result shows the noticeable inactivation efficiency by gaseous ozone compared with previous studies. Good performance by wet ozone was also found for military material surface.(i.e. : gas mask hood, protective garments, army peinted metal surface).

• Journal of the Korean GEO-environmental Society
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• v.11 no.5
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• pp.15-23
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• 2010

Dry sieving, wet sieving and photoscattering analyzer were tested as particle size analyzing methods for sediments from rivers and lakes of Han river, Nakdong river, Youngsan river, and Kumgang river area. Dry sieving showed a big error due to coagulating effect over drying process and this phenomena was severe for lake sediment. Wet sieving and PSA showed an accurate results though wet sieving needs more labor and complicate processes. Freeze-dry or freeze-dry after oxidation of organics with hydrogen peroxide showed improved results but gave lower portion of fine particles in comparing with wet sieving. Heavy metal contents and extractable metal contents were investigated for the sediments and high heavy metal content and extractable amount were obtained from fine particles as expected. Using of proper particle size analyzing method is important and the sediment management should be focused on the fine particles.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.1
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• pp.27-35
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• 2018

The stability of liquid ferrate(VI) produced by an innovative method was confirmed and the degradation characteristics of cyclic compounds(Benzene, Aniline, Toluene, 1,4-Dioxane) by liquid ferrate(VI) were investigated under the same reaction conditions. When it was compared with the ferrate manufactured by the wet oxidation method, the liquid ferrate was more stable. And the stability of liquid ferrate was tested at the storage temperature. As a result, only 17.7% of liquid ferrate(VI) has decomposed at the storage temperature($4^{\circ}C$) for 28 days. Among the cyclic compounds, the aniline was rapidly degraded compare to other cyclic compounds, which seems to be due to the electron-donating ability of the substituent, $-NH_2$ group. Especially, when 1,4-dioxane was compared with benzene, the decomposition rate of 1,4-dioxane was lower than that of benzene, suggesting that oxygen atoms hinder the electrophilic reaction. Among 4 cyclic compounds, it was observed that aniline has the highest rate constant than those of other cyclic compounds.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.537-544
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• 2011

This work was conducted to investigate the oxidation characteristics of methane having the highest ignition temperature among the other hydrocarbon gases using transition metal catalysts. The catalyst used for methane oxidation was manganese oxide having a various oxidation number, such as MnO, $MnO_2$, $Mn_2O_3$, $Mn_3O_4$, $Mn_4O_5$. The manganese oxide(MnxOy) catalyst is impregnated on $TiO_2$, $Al_2O_3$ for methane oxidation. To enhanced both of activity and life time of catalysts, Ni and Co was used as a promoter. In this study, various co-catalysts were synthesized by using excess wet impregnation method. The effect of reaction temperature and space velocity was measured to calculate the activity of catalysts such as, activation energy of $T_{50}$, and $T_{90}$. The life time of bi-metallic manganese mixture, such as Mn-Co and Mn-Ni catalysts, were increased more 10 % than manganese oxide catalyst, but activity of those was decreased slightly.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.248-254
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• 2016

Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.722-728
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• 2005

A wet-chemical route was utilized to obtain nanosized crystalline goethite ($\alpha$-FeOOH) particle, which was known as an oxidation catalyst in reducing carbon monoxide (CO) and dioxine during incineration. A cost-effective $FeSO_4{\cdot}7H_2O$ was used as starting raw material and a successive process of hydrolysis-oxidation was utilized as synthetic method. The effects of the initial $Fe^{2+}$ concentration, hydrolysis time and oxidation period on the crystalline phase and particle characteristics were systematically investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and BET analyses. It was found that the spindle-shaped crystalline $\alpha$-FeOOH particle with the width of 70 nm and the length of 200 nm could be obtained successfully when the initial concentration of 1.5 M, hydrolysis time of 4h, and oxidation period of 10 h, respectively. In addition, it was observed that the spindle-shaped $\alpha$-FeOOH particle consisted of nano-sized primary crystallites of $30\~50\;nm$, which were de-agglomerated into individual particle and successively re­agglomerated into spherical or irregular-shaped agglomerates beyond certain periods in the hydrolysis and oxidation process.

• Asian Journal of Atmospheric Environment
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• v.7 no.3
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• pp.169-175
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• 2013

Measurement of the phosphorus concentration in aerosols in Beijing, which was a representative East Asian mega-city, was carried out. The optimum procedure for analyzing phosphorus in aerosols was found in this study. Recovery of phosphorus in environmental samples through the improved method was almost 100%. The concentration of phosphorus in TSP was $145{\pm}47\;ng/m^3$, with a seasonal variation showing high concentrations in winter and low concentrations in summer. The concentrations of phosphorus in $PM_{2.5}$ accounted for $35{\pm}6%$ of those in TSP, with no seasonal variations. The major source of phosphorus in aerosols in Beijing was soil dust, and additional sources of phosphorus in fine particles could be coal combustion and biomass burning.