• 한국환경보건학회지
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• 제31권5호
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• pp.404-410
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• 2005

The pH efforts on the removal of 1,4-dioxane and the biodegradobility enhancement of dioxane contaminated water were investigated using $O_3/H_2O_2$ baled advanced oxidation process. Experiments were conducted using a bubble column reactor under different initial pH. The $O_3/H_2O_2$ process effectively converted 1,4-dioxane to more biodegradable intermediates which had a maximum $BOD_5$ enhancement at pH 11 within the experimental range, precisely, when the initial pH increased, $BOD_5$ enhanced. However, in case of removal efficiencies of 1,4-dioxane during $O_3/H_2O_2$ oxidation the optimum condition was shown at pH 9 compared with pH 6 and 11. TOC and COD values were not largely changed for all reaction time. From the results of 1,4-dioxane removal efficiency, TOC, COD, and $BOD_5$ enhancement with reaction time, it was surely observed that 1,4-dioxane was just converted to biodegradable materials, not completely oxidized to carbon dioxide.

• 한국산학기술학회논문지
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• 제5권4호
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• pp.331-335
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• 2004

본 논문에서는 반도체 공정 시뮬레이션을 위해 산화, 확산 및 이온 주입 공정을 모델링하고, 효율적인 실행과 상호 연관된 연속 공정의 시뮬레이션이 가능하도록 통합화된 환경을 구축하였다. 점성적 스트레스 모델을 이용한 산화 공정은 유속-압력 알고리즘과 경계요소법을 이용하여 안정된 해를 얻었으며, 선확산과 산화증배 현상이 포함된 확산 공정은 전진해법과 유한요소법을 이용하였다 또한 이온 주입 공정은 TRIM을 기본으로 다양한 공정 조건에 대한 모델이 추가된 몬테카를로 방법을 사용하였다. 편리한 사용자 입력 인터페이스와 그래픽적 출력을 제공하고, 윈도즈의 API함수를 이용하여 PC상에서 적은 메모리로도 빠른 결과를 얻을 수 있도록 하였으며, 객체 지향적인 모듈화로 타 시뮬레이터와의 호환성이 가능하도록 구성하였다.

• 대한전자공학회논문지SD
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• 제40권8호
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• pp.560-564
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• 2003

본 논문에서는 RTP(rapid thermal process)를 이용한 새로운 산화방법을 고안했으며, 이는 짧은 시간에 다공질 실리콘을 산화시킴으로써 이 기술은 여타 방법에 비해 경제적이고 간편한 방법으로 짧은 시간에 두꺼운 산화막을 성장시킬 수 있는 장점을 가지고 있다. 먼저, 양극반응을 통해 PSL(porous silicon layer)을 형성한 후 이를 저온 산화시킨 후에 급속 열처리 산화공정(RTO: rapid thermal oxidation)를 이용해서 OPSL(oxidized porous silicon layer)을 제조하고, 그 물성 및 전기적 특성을 조사하여, 열 산화로 제작된 OPSL과 그 특성을 비교하였다. 시편의 절연 파괴전압은 약 3.9 MV/cm의 값을 보여 벌크 산화막보다는 적은 값이지만 절연 재료로서는 충분한 값이고, 누설전류는 0 ∼ 50 V의 인가 전압에서 100 ∼ 500 ㎀의 값을 보였다. 그리고, XPS 결과는 RTO 공정 추가가 저온 산화막의 완전 산화에 크게 기여함을 확인하였으며, 저온 산화막의 표면 및 내부에서도 산화반응이 완전하게 이루어졌음을 확인하였다. 이 결과로부터 저온 OPSL을 제조할 때, RTO 공정이 OPSL의 산화 및 치밀화(densification)의 증가에 크게 기여함을 알 수 있었다. 따라서, 이의 방법으로 제조된 OPSL은 저온을 요구하는 공정에서 소자의 절연막, 전기적인 분리층 그리고 실리콘 고주파용 기판 등으로 활용될 수 있을 것으로 보인다.

• 한국물환경학회지
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• 제38권6호
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• pp.267-274
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• 2022

This paper is a result of research conducted on the 800,000 m³/d capacity of A Water Treatment Plant (WTP) and 400,000 m³/d capacity of B WTP plant in operation in the Nakdong River region. We evaluated the effect of algae broom on the WTP operation based on the running data of both WTP and the data on the pre-oxidation process field test for algae control using sodium permanganate (SPM) at the B WTP. The study results showed that during the algal bloom period, the coagulant dose increased by 102% in A WTP and 58% in B WTP, respectively, and the chlorine dose also increased by 38% and 29%, respectively, which may affect Total trihalomethane (THM) production. Data such as algal populations and Chl-a, residual chlorine and THM, algal populations, and ozone dose appeared also highly correlated, confirming that algal broom affects WTP operations, including water quality and chemical dosage. As a result of the field test of B WTP, THMs appeared lower than that of the control, suggesting the possibility of the SPM pre-oxidation process as an alternative to algae-related water quality management. Furthermore, in terms of GHG emissions due to energy consumption, it was observed that the pre-oxidation process using SPM was approximately 10.8%, which is a very low ratio compared to the pre-ozonation process. Therefore, these results suggest that the SPM pre-oxidation process can be recommended as an alternative to low-carbon water purification technology.

• 환경위생공학
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• 제16권4호
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• pp.69-76
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• 2001

The catalytic oxidation of volatile organic compounds (VOCs), which were benzene and toluene, was studied in the supercritical carbon dioxide($SC-CO_2$) media. In $SC-CO_2$ media, the deep oxidation conversion of VOCs was increased with the temperature and pressure. The deep oxidation conversion in SC -$CO_2$ media is better than that in air media at same pressure condition. This can be explained by the solubility of VOCs in $SC-CO_2$. The many intermediates produced by the partial oxidation of VOCs were detected from off-line samples. The intermediates were Identified as benzene, toluene, benzaldehyde, phenol, naphthalene, 1,1`-biphenyl, benzoic acid, 3-methylphenol, 1,1'-(1,2-ethanediyl)bis- benzene, 1,1'-(1,2-ethene- diyl)bis-benzene, anthracene, and so on. The amount of intermediates was decreased as the molar radio of oxygen to carbon dioxide was decreased. When the molar ratio of oxygen to carbon dioxide was 1 : 16, the deep conversion was kept constant. Thus, the catalytic oxidation process in $SC-CO_2$ media can be combined on-line with supercritical fluid extraction of environmental matrices and supercritical regeneration of used adsorbent. Thus, the nontoxic $SC-CO_2$ media process was suggested as the new VOCs control technology.

• Asian Journal of Atmospheric Environment
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• 제8권1호
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• pp.1-14
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• 2014

Migration of methane ($CH_4$) gas from landfills to the surrounding environment negatively affects both humankind and the environment. It is therefore essential to develop management techniques to reduce $CH_4$ emissions from landfills to minimize global warming and to reduce the human risks associated with $CH_4$ gas migration. Oxidation of $CH_4$ in landfill cover soil is the most important strategy for $CH_4$ emissions mitigation. $CH_4$ oxidation occurs naturally in landfill cover soils due to the abundance of methanotrophic bacteria. However, the activities of these bacteria are influenced by several controlling factors. This study attempts to review the important issues associated with the $CH_4$ oxidation process in landfill cover soils. The $CH_4$ oxidation process is highly sensitive to environmental factors and cover soil properties. The comparison of various biotic system techniques indicated that each technique has unique advantages and disadvantages, and the choice of the best technique for a specific application depends on economic constraints, treatment efficiency and landfill operations.

• 한국수소및신에너지학회논문집
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• 제20권4호
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• pp.337-343
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• 2009

Noncatalytic partial oxidation of methane for producing synthesis gas was studied in a lab-scale experimental apparatus. Partial oxidation developed for high-temperature, fuel-rich combustion and it is exothermic process. but Steam reforming and Caron reforming is highly endothermic process to need much energy. Noncatalytic partial oxidation of methane is affected by temperature and equivalent ratio, so we studied effect about composition of synthesis gas at lab scale reactor. We used electronic heater to control the temperature of reactor. The quality of synthesis gas is improved and reduced heat value to require at Noncatalytic partial oxidation because the reacting temperature is lower at oxy condition.

• 한국환경과학회지
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• 제4권5호
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• pp.115-115
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• 1995

Reuse of industrial effluents through the cooling systems in a petrochemical complex was described. The partial oxidation of the effluents from the biological treatment plant was examined, using Fenton''s reagent as a pretreatment step prior to a next treatment of the effluents. Next tertiary treatment using fixed-film reactor resulted in marked reductions in COD and suspended solids. The continuous fixed-film process with Fenton oxidation pretreatment showed a 23% increase in the COD removal efficiency when compared to that without pretreatment of Fenton oxidation under the volumetric organic loading rate of 0.1 kg COD/m3/day. The Fenton oxidation treatment seemed to be a possible method for tertiary biological treatment to reduce the residual toxicity with the enhanced biodegradation of the effluents.

• 한국환경과학회지
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• 제4권5호
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• pp.501-508
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• 1995

Reuse of industrial effluents through the cooling systems in a petrochemical complex was described. The partial oxidation of the effluents from the biological treatment plant was examined, using Fenton's reagent as a pretreatment step prior to a next treatment of the effluents. Next tertiary treatment using fixed-film reactor resulted in marked reductions in COD and suspended solids. The continuous fixed-film process with Fenton oxidation pretreatment showed a 23% increase in the COD removal efficiency when compared to that without pretreatment of Fenton oxidation under the volumetric organic loading rate of 0.1 kg COD/m3/day. The Fenton oxidation treatment seemed to be a possible method for tertiary biological treatment to reduce the residual toxicity with the enhanced biodegradation of the effluents.

• 한국재료학회지
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• 제13권12호
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• pp.825-830
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• 2003

Structural changes during oxidation of anisotopic mesophase carbon fiber(AMCFs) have been observed with TEM and XRD. It was shown that the AMCFs are three dimensionally stacked structure of turbostratic layers, and are non-homogeneous structure which consist of the highly ordered areas and the random areas. The $d_{ 002}$, Lc, and La of AMCFs which were measured by XRD were 3.44, 146, and $135\AA$, respectively. It was observed that the oxidation initiated at the random areas, because the $d_{002}$ / decreased to the value of 3.41 $\AA$ during initial oxidation stage. It was also observed that the La of the oxidized AMCFs increased up to 182 $\AA$ during the whole oxidation process, and the $d_{002}$ of that increases up to 9.44 $\AA$ when the burn-off is over the degree of 20%. Therefore, it was suggested that the micro-crystalline grew up by heat treatment effects during the fibers were oxidized, In addition, it was shown that there was difference in the measured value of La by XRD and TEM, in case of 39% oxidized fibers for example, the measured La was $ 165\AA$ by XRD and in the range of 180∼220 $\AA$ by TEM.