• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.345-351
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• 2004

We investigated the anaerobic ammonium oxidation (anammox) reaction in a lab-stale upflow anaerobic sludge blanket (UASB) reactor. Our aim was to detect and enrich the organisms responsible for the anammox reaction using a synthetic medium that contained low concentrations of substrates (ammonium and nitrite). The reactor was inoculated with granular sludge collected from a full-scale anaerobic digestor used for treating brewery wastewater The experiment was performed during 260 days under conditions of constant ammonium concentration ($50\;mg\;NH_4^+-N/L$) and different nitrite concentrations ($50{\~}150\;mg\;NO_2-N/L$). After 200 days, anammox activity was observed in the system. The microorganisms involved in this anammox reaction were identified as Candidatus B. Anammoxidans and K. Stuttgartiensis using fluorescence in situ hybridization (FISH ) method.

• 한국주조공학회지
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• 제15권3호
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• pp.272-282
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• 1995

Iron-based metal matrix composites have been recently investigated for the use of inexpensive abrasion resistance material. This paper carried out to investigate the in-situ reaction effects on the microstructural characteristics and the formation mechanism of tungsten carbides in a white cast iron matrix. The specimens of Fe-3.2%C-2.8%Si alloy cast-bonded with tungsten wire were cast in the metal mold and isothermally heat treated at $950^{\circ}C$ up to 48 hours. The typical microstructure of heat treated specimens showed the reaction layer of WC at the interface of tungsten wire and the carbon depletion zone between the WC layer and the matrix. During the formation of WC layer, if the carbon supply is insufficient due to the decarburization of matrix or the isolation of matrix by cast-bonded W wires, the reaction layer develops coarse hexagonal crystalline WC. From the microstructural investigation, it was found that the volume of WC layer and the carbon depletion zone increased linearly with the isothermal heat treating time. This results supported that the formation rate of WC in the white cast iron matrix is controlled by the interfacial reaction with a constant reaction rate.

• Composites Research
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• 제33권5호
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• pp.256-261
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• 2020

본 연구에서는 Al-Ti-C 반응계의 점화온도에 대해 고찰하고, 자전연소합성법 및 교반주조 공정을 통해 TiC/Mg 금속복합재료를 제조하여 미세조직 및 기계적 특성을 분석하였다. 0, 10, 20, 30 vol.% TiC 입자가 균일하게 분산된 Mg 복합재료를 제조하였고, 강화재의 양이 증가할수록 기지 대비 우수한 압축강도 및 내마모특성을 보였다. 이는 in-situ 자전연소합성법에 의해 결함이나 불순물 등의 오염이 적은 TiC/Mg 금속복합재료 제조로 기지에서 강화재로의 효과적인 하중 전달에 의한 것으로 판단된다.

• 한국재료학회지
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• 제17권6호
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• pp.313-317
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• 2007

In-situ micro-channeled multi tubular solid oxide fuel cell(SOFC) was fabricated using multi-pass extrusion process with out side diameter of 2.7 mm and active length of 5 mm that contained 61 individual cells. Cell materials used in this work were NiO-YSZ (50 : 50 vol.%), 8 mol% yttria-stabilized zirconia(8YSZ), $La_{0.8}Sr_{0.2}MnO_3(LSM)$ as anode, electrolyte, and cathode, respectively. The arrangement of each electrode and electrolyte layer in green bodies showed uniformity and integrity after extrusion and sintering. The XRD analysis confirmed that no reaction phases appeared and the microstructure of the electrolyte was fairly dense (relative density > 96%) after sintering.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.322-325
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• 2003

The feasibility of treating 2-chlorophenol (2CP) contaminated soils with ozone venting was investigated in this research. Adding ozone to the existing air-venting process provides an alternative to achieve a complete in-situ treatment by oxidizing the contaminant in the process. A column study with artificial soil was used to simulate the venting process. Ozone concentrations at 2.4, 7.6 and 19.4 mg/L, and flow rates at 100 and 150 mL/min were used. The reaction times were 10, 20, 50, and 60 minutes. Blank samples using air venting were also run for comparison. It is obvious that ozone-venting had a much faster removal rate than air-venting. As higher concentration of ozone is applied, the reaction rate increased significantly. As higher concentration was applied, the flux of ozone to the liquid film increased. This also increased the removal rate of 2CP and therefore the breakthrough curve came out earlier.

• Korean Chemical Engineering Research
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• 제57권6호
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• pp.853-860
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• 2019

나날이 엄격해지는 환경 규제를 만족시키기 위하여, 고체 입자를 유체처럼 이용하는 순산소 순환유동층 및 초초임계 순환유동층 발전 기술이 전세계에서 개발되고 있다. 순환유동층 발전 공정들에서 미세먼지, 산성비의 주범으로 알려진 황산화물을 저감하는 전통적인 방법은 황산화물과 반응하는 석회석을 보일러 내에 직접 주입하는 것이다. 그러나 보일러 내에 주입된 석회석은 다양한 조업 변수들(온도, 압력, 고체 순환속도, 층밀도, 체류시간 등)의 영향을 받아 탈황 성능이 지속적으로 변화하게 된다. 이에 본 연구에서는 기존에 발표된 탈황 반응 속도식과 순환유동층의 수력학적 특성식들을 결합하여 순환유동층 보일러에서 석회석과 순환유동층 운전 특성들만으로 탈황 효율을 예측하는 식을 개발하였다. 특히 다양한 국내 석회석들의 탈황 반응들로부터 얻어진 실험 결과들을 이용하여 탈황 효율 예측식을 개선하였다.

• 대한금속재료학회지
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• 제48권8호
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• pp.780-789
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• 2010

The aim of this study is to evaluate the microstructure and tensile property of in-situ (TiB+TiC) particulate reinforced titanium matrix composites (TMCs) synthesized by the investment casting process. Boron carbide ($1,500{\mu}m$ and $150{\mu}m$) was added to the titanium matrix during vacuum induction melting, which can provide the in-situ reaction of $5Ti+B_4C{\rightarrow}4TiB+TiC$. 0.94, 1.88 and 3.76 wt% of $B_4C$ were added to the melt. The phases identification of the in-situ synthesized TMCs was examined using scanning electron microscopy, an X-ray diffractometer, an electron probe micro-analyzer and transmission electron microscopy. Tensile properties of TMCs were investigated in accordance with the reinforcement size and volume fraction. The improvement of tensile property of titanium matrix composites was caused by load transfer from the titanium matrix to the reinforcement and by grain refinement of titanium matrix and reinforcements.

• 한국건축시공학회지
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• 제24권1호
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• pp.1-10
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• 2024

In-situ 탄산화 기술은 시멘트 기반 건설재료의 제조과정에서 CO₂를 주입하여 시멘트 수화과정에서 용출되는 Ca²⁺ 이온과 CO₂의 탄산화 반응을 통해 CaCO₃의 형태로 CO₂를 격리하는 광물탄산화 기술이며, 본 연구에서는 현재 국내 건설현장에서 시공되고 있는 바닥용 건조시멘트 모르타르 배합의 범위에서 In-situ 탄산화 기술을 적용 시, CO₂의 주입 유량 및 총 주입량을 검토하고, 바인더인 단위시멘트량 감축에 따른 제품의 품질 검토를 실시하였다.

• 한국재료학회지
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• 제17권1호
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• pp.11-17
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• 2007

Turbulent in-situ mixing process is a new material process technology to get dispersed phase in nanometer size by controlling reaction of liquid/solid, liquid/gas, flow ana solidification speed simultaneously. In this study, mixing which is the key technology to this synthesis method was studied by computational fluid dynamics. For the simulation of mixing of liquid metal, static mixers investigated. Two inlets for different liquid metal meet ana merge like 'Y' shape tube having various shapes and radios of curve. The performance of mixer was evaluated with quantitative analysis with coefficient of variance of mass fraction. Also, detailed plots of intersection were presented to understand effect of mixer shape on mixing. The simulations show that the Reynolds number (Re) is the important factor to mixing and dispersion of $TiB_2$ particles. Mixer was designed according to the simulation, and $Cu-TiB_2$ nano composites were evaluated. $TiB_2$ nano particles were uniformly dispersed when Re was 1000, and cluster formation and reduction in volume fraction of $TiB_2$ were found at higher Re.

• 한국환경과학회지
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• 제9권1호
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• pp.43-47
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• 2000

A study on the remediation of heavily for ion contaminated soils from abandoned iron mine was carried out, using ex-situ extraction process. Also, oxalic acid as a complex agent was evaluated as a function of concentration, reaction time and mixing ratio of washing agent in order to evaluate Fe removability of the soil contaminated from the abandoned iron mine. Oxalic acid showed a better extraction performance than 0.1N-HCl, i.e., the concentrations of Fe ion extracted from the abandoned mine for the former at uncontrolled pH and the latter were 1,750 ppm and 1,079 ppm, respectively. The optimum washing condition of oxalic acid was in the ratio of 1:5 and 1:10 between soil and acid solution during l hr reaction. The total concentrations of Fe ion by oxalic acid and EDTA at three repeated extraction, were 4,554 ppm and 864 ppm, respectively. The recovery of Fe ions from washing solution was achieved, forming hydroxide precipitation and metal sulfide under excess of calcium hydroxide and sodium sulfide. In addition, the amounted of sodium sulfide and calcium hydroxide for the optimal revovery of Fe were 15g/$\ell$ and 5g/$\ell$ from the oxalic acid complexes, respectively.