• 한국응용과학기술학회지
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• 제33권1호
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• pp.100-109
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• 2016

본 연구에서는 촉매 상 $H_2O_2$ 전환에 의해 건식산화제가 생성되었으며, 이를 이용한 NO 산화 공정에 대한 연구를 진행하였다. 건식산화제를 생성하기 위한 $H_2O_2$ 촉매 전환에 관한 실험을 수행한 결과, Mn계 촉매의 성능이 가장 우수하였으며, 이를 통해 생성된 건식산화제를 NO 산화공정에 주입하여 다양한 운전조건에서 NO 산화특성을 조사하였다. 그 결과, $H_2O_2$ 주입량, 산화반응온도, 그리고 공간속도가 NO 산화율에 크게 영향을 미치는 것을 확인하였다. 그리고, 산화반응온도와 $H_2O_2$ 주입량이 증가할수록 NO 산화효율이 증가하였으며, 공간속도가 증가할수록 NO 산화효율이 감소하였다.

• 한국환경과학회지
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• 제15권3호
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• pp.193-201
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• 2006

Advanced oxidation processes involving $O_3/H_2O_2$ and $O_3/catalyst$ were used to compare the degradability and the effect of pH on the oxidation of 1,4-dioxane, Oxidation processes were carried out in a bubble column reactor under different pH. Initial hydrogen peroxide concentration was 3.52 mM in $O_3/H_2O_2$ process and 115 g/L (0.65 wt.%) of activated carbon impregnated with palladium was packed in $O_3/catalyst$ column. 1,4-dioxane concentration was reduced steadily with reaction time in $O_3/H_2O_2$ oxidation process, however, in case of $O_3/catalyst$ process, about $50{\sim}75%$ of 1,4-dioxane was degraded only in 5 minutes after reaction. Overall reaction efficiency of $O_3/catalyst$ was also higher than that of $O_3/H_2O_2$ process. TOC and $COD_{cr}$ were analyzed in order to examine the oxidation characteristics with $O_3/H_2O_2\;and\;O_3/catalyst$ process. The results of $COD_{cr}$ removal efficiency and ${\Delta}TOC/{\Delta}ThOC$ ratio in $O_3/catalyst$ process gave that this process could more proceed the oxidation reaction than $O_3/H_2O_2$ oxidation process. Therefore, it was considered that $O_3/catalyst$ advanced oxidation process could be used as a effective oxidation process for removing non-degradable toxic organic materials.

• 한국환경보건학회지
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• 제24권3호
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• pp.63-69
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• 1998

The treatment of soils and water contaminated with MTBE using the Fenton oxidation was investigated. The effects of dosage of $H_{2}O_{2}$, and Fe$^{2+}$ concentrations, and solution pH on transformation and mineralization in soil were evaluated. Generation of TBA and acetone following Fenton-oxidation of MTBE in water and generation of acetone following Fenton-oxidation of TBA were observed. Therefore TBA and acetone are degradation intermediates of MTBE. There was a large difference of treatment efficiency in Fenton oxidation of MTBE between soil and water system. This may be caused by the complex nature of soil, soil organic matter which can consumed OH $\cdot$ radicals, and interacting with inorganic-soil constituents. The pH of soil was observed to have a significant effect on the chemical oxidation efficient of MTBE in soil The data demonstrated that optimal pH range were pH 3~4 and around 6. The soil batch studies demonstrated that treatment efficiency of MTBE was enhanced by adding additional ferrous salts but Fenton-oxidation occurred in no additional iron which indicated that iron in soil can catalyze the Fenton-oxidation. The most effective parameter of Fentonoxidation was $H_{2}O_{2}$/Fe$^{2+}$ ratio which theocratical ratio is 0.5. The optimal range of this ratio was found to be 0.6~2.3. In evaluating effect of $H_{2}O_{2}$ dosage on treatment efficiency, the increase of $H_{2}O_{2}$ did not always lead to increase of decompositions of MTBE in soil. Fenton oxidation was effective in destroying MTBE in aqueous extracts of contaminated soil and water. Experimental data provided evidence that the Fenton oxidation can effectively remediate MTBE-contaminated water and soil.

• 마이크로전자및패키징학회지
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• 제8권2호
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• pp.1-7
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• 2001

저열팽창성 금속인 Kovar표면을 유리와 접합하기에 적합한 spinel을 주상으로 하는 균일한 산화막을 형성할 수 있도록 $N_2/H_2$에 $H_2O$가 첨가된 분위기에서의 산화 거동에 대하여 조사하였다. Kovar 산화는 확산에 의해 지배되는 공정이며, 이때 산화 활성화 에너지는 31.61 kacl/mol 이었다. $600^{\circ}C$에서 열처리한 결과 spinel을 주상으로 하는 0.5 $mu extrm{m}$ 이하의 연속적이고 균일한 외부 산화막을 얻을 수 있었다. TEM 분석 결과 격자 상수가 7.9 $\AA$인 spinel 임을 확인할 수 있었다. 그러므로, 가습된 $N_2/H_2$분위기에서 산화한 Kovar는 유리와 접합에 적용 가능할 것으로 판단된다.

• 한국세라믹학회지
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• 제22권6호
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• pp.5-8
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• 1985

Graphite has been oxidized to graphite hydrogen sulfate in concentrated $H_2SO_4$. Anodic oxidation and chemical oxidation of graphite in $H_2SO_4$ generally leads to the formation of intercalation compounds of the ionic salt type through incorporation of $H_2SO_4^-$ions and $H_2SO_4$ molecules into the graphite. Several other reactions also accur at various points of the charging cycle. But there is no satisfactory kinetics and mechanism of intercalationin graphite. We have studied them with anodic oxidation and chemical oxidation. We found six distinct phenomena between 2nd stage and 1st stage in chemical oxidation. We examined them in detail by the following in the measurements electrical oxidation. X-ray diffractions UV-Vis spectroscopy density measurements. We could obtained a equation for kinetic according to the reaction rate from this results and mechanism of intercalation between 2nd stage and 1st stage with hydrogen sulfate in graphite. Three thesis were written for the mechanism of intercalation compounds in graphite with hydrogen sulfate ; first thesis is anodic oxidation second thesis is chemical oxidation and definition of transit phase between 2nd etc the third thesis is the kinetic mechanism of intercalation compounds in graphite with Hydrogen sulfate. This thesis is the first paper among three thesis as anodic oxidation.

• 한국세라믹학회지
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• 제48권5호
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• pp.426-432
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• 2011

The oxidation behavior of CVD ${\beta}$-SiC was investigated for Very High Temperature Gas-Cooled Reactor (VHTR) applications. This study focused on the surface analysis of the oxidized CVD ${\beta}$-SiC to observe the effect of impurity gases on active/passive oxidation. Oxidation test was carried out at $950^{\circ}C$ in the impurity-controlled helium environment that contained $H_2$, $H_2O$, CO, and $CH_4$ in order to simulate VHTR coolant chemistry. For 250 h of exposure to the helium, weight changes were barely measurable when $H_2O$ in the bulk gas was carefully controlled between 0.02 and 0.1 Pa. Surface morphology also did not change based on AFM observation. However, XPS analysis results indicated that a very small amount of $SiO_2$ was formed by the reaction of SiC with $H_2O$ at the initial stage of oxidation when $H_2O$ partial pressure in the CVD ${\beta}$-SiC surface placed on the passive oxidation region. As the oxidation progressed, $H_2O$ consumed and its partial pressure in the surface decreased to the active/passive oxidation transition region. At the steady state, more oxidation did not observable up to 250 h of exposure.

• 미생물학회지
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• 제21권2호
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• pp.79-85
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• 1983

Ammonia oxidation activity of polluted water samples in Jinhae Bay and isolated strain from the seawater was investigated, and effects of environmental factors such as temperature, salinity, substrate concentration to the ammonia oxidation were also investigated. The ammonia oxidation activities of sediments, 0.01-0.04mg eq. $NO_2-N/l/h$, were exceptionally higher than that of sea water, $0.5{\sim}1{\mu}g$ eq. $NO_2-N/l/h$. the activities of muddy sediments at station 4 and 2 were 0.03~0.04mg eq. $NO_2-N/l/h$ and that of sandy sediment at station 3 was 0.002mg eq. $NO_2-N/l/h$. In the case of sea water, the activity of polluted area, station 1, was 2 times higher than that of offshore, station 4. The isolated strain reached log phase after 30days culturs and its oxidation activity was $2{\sim}3{\mu}g$ eq. $NO_2-N/day$. The maximum oxidation of ammonia by IA 13 strain occured at 30mg/l oxidation increased with the salinity rising up to 100% seawater concentraion. And temperature for maximum oxidation of ammonia was $35^{\circ}C$. the oxidation increased with the salinity rising up to 100% seawater concentration.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3659-3664
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• 2023

The electrochemical behavior of dissolved hydrogen (H₂) was investigated at a Pt electrode in a high temperature LiOH-H₃BO₃ solution. The diffusion current of the H₂ oxidation was proportional to the concentration of the dissolved H₂ as well as the reciprocal of the temperature. In the polarization curve, a potential region in which the oxidation current decreases despite an increase in the applied potential between the H₂ oxidation and the water oxidation regions was observed. This potential region was interpreted as being caused by the formation of a Pt oxide layer. Using the properties of the Cl^- ion that reduces the growth rate of the Pt oxide layer, it was confirmed that there is a correlation between the Cl^- ion concentration and the transient current of the H₂ oxidation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.222-224
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• 1993

In this paper, The optimum oxidation conditions for the formation of Cu-Zn ferrite were investigated using precipitates obtained by the mixture of $CuCl_2{\cdot}2H_2O$, $ ZnCl_2$, $FeCl_3{\cdot}6H_2O$ and NaOH. The precipitates were prepared by coprecipitation method on various temperatures and oxidation conditions. The oxidation products were examined by SEM, XRD, and VSM. The particles obtained at 70($^{\circ}C$) were more spherical and fine than that of prepared at 25($^{\circ}C$), 50($^{\circ}C$), 60($^{\circ}C$), respectively. By $H_2O_2$ oxidation, the saturation magnetization of the powders was little influenced, But, by air oxidation the saturation magnetization of the powders was influenced intricately. According to our experimental data, the saturation magnetization of the powders increased with reaction time and was saturated at 9 hours.

• 공업화학
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• 제21권2호
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• pp.183-187
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• 2010

본 연구에서 $H_2O_2$에 의한 pitch의 산화처리가 KOH 활성화에 미치는 영향에 관하여 고찰하였다. 산화 처리의 영향을 고려하기 위하여 KOH/pitch 중량비를 3으로 고정하였으며, 1073 K에서 2 h 동안 활성화하였고, $H_2O_2$의 농도를 각각 5, 15, 25 wt%로 달리하여 시편을 제조하였다. 산화처리된 pitch와 이를 전구체로 하여 제조한 활성탄소의 물리화학적 특성은 XRD, FT-IR, XPS, $N_2$ 흡착 및 SEM을 이용하여 분석하였다. XRD 결과로부터 $H_2O_2$ 처리가 (002) 면의 층간거리를 증가시켰으며, FT-IR과 XPS로부터 표면의 carboxyl group 및 hydroxyl group 등의 산소 작용기가 도입되었음을 확인하였다. Pitch로 제조된 활성탄소의 비표면적은 $H_2O_2$ 산화처리에 의해 급격히 상승하였고, $H_2O_2$의 농도를 증가시킬수록 상승폭이 더욱 증가하여 25 wt% $H_2O_2$ 처리시 최대 $2111m^2/g$의 비표면적을 갖는 활성탄소를 제조할 수 있었다.