• 한국환경보건학회지
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• 제23권4호
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• pp.127-132
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• 1997

The characteristics of the ozone treatments of phenol were studied in a laboratory scale wastewater treatment system. The ozone treatment of wastewater was carried out in a batch-type reactor. The initial pH of wastewater(7-10), volumetric flow rate(1-2l/min) and ozone concentration(20~30 mg/l) of aerating gas were considereal as experimental variables in the ozone treatment. Phenol was decomposed easily by the ozone in a batch treatment, where the rate determining step was the COD removal that is decomposition of intermediates formed by the ozonation of phenol. Phenol decomposition and COD removal could be expressed by the first order reaction for the phenol concentration and COD, respectively. Rate constants of phenol decomposition and COD removal increased with the initial pH, volumetric flow rate and ozone concentration of aeration gas. Under the present experimental condition, their relationships could be given by for the phenol decomposition $k'=4.46\times 10^{-9}[pH]_o ^{3.94}[O_3]^{1.42}Q_{O3}^{1.57}$ for the COD removal $k=2.46\times 10^{-10}[pH]_o ^{5.19}[O_3]^{1.15}Q_{O3}^{1.19}$

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.85-88
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• 2006

A fluidized bed reactor made of quartz with 0.055m I.D. and 1.0m in height was employed for the thermocatalytic decomposition of propane to produce $CO_2$-free hydrogen. The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. The propane decomposition rate used carbon black N33O as a catalyst. The propane decomposition reaction was carried out at the temperature range of $600{\sim}800^{\circ}C$, paropane gas velocity of $1.0 U_{mf}\;3.0U_{mf}$ and the operating pressure of 1.0 atm. Effect of operating parameters such as reaction temperature, gas velocity on the reaction rates was investigated. The carbon which was by-product of methane decomposition reaction was deposited on the catalyst surface that was observed by SEM. Resulting production in our experiment were not only hydrogen but also several by products such as methane, ethylene, ethane, and propylene.

• 한국기후변화학회지
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• 제8권1호
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• pp.63-71
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• 2017

It is recognized that tetrafluoromethane ($CF_4$) has a great influence on global warming. The $CF_4$ is known to have a large impact on climate change due to its large global warming index. In this study, a waterjet plasma scrubber (WPS) was designed and manufactured for the $CF_4$ decomposition. The WPS is a novel technology which is combined a gliding arc plasma and water injection at the center of the plasma discharge. This can give an innovative way for $CF_4$ decomposition by achieving larger plasma columnand generating OH radicals. A performance analysis was achieved for the design factors such as waterjet flow rate, total gas flow rate, consumption electric power, and electrode gap. The highest $CF_4$ decomposition and energy efficiencies were 64.8% and 6.43 g/kWh, respectively; Optimal operating conditions were 20 mL/min of waterjet flow rate, 200 L/min total gas flow rate, 5.3 kW consumption electric power, and 4.4 mm electrode gap. As for the 2 stage reactor of the WPS, the $CF_4$ decomposition efficiency improved as the 85.3% while the energy efficiency decreased as the 5.57 g/kWh.

• 한국세라믹학회지
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• 제39권10호
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• pp.988-993
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• 2002

Lanthanum Stannate Pyrochlore($La_2Sn_2O_7$) 촉매를 이용하여 $NO_x$ 제거를 위한 전기화학 촉매 셀을 제조하였다. 촉매전극은 수열합성법을 통해 합성한 $La_2Sn_2O_7$ 분말과 안정화 지르코니아(YSZ) 분말을 혼합하여 촉매층 페이스트를 제조한 후 이를 YSZ 디스크 고체전해질 위에 스크린프린팅하여 후막을 도포하였다. 위와 같이 제조한 전기화학 셀의 $NO_x$ 분해 실험은 galvanostat을 이용하여 셀에 일정한 전류를 인가하고 700${\circ}C$에서 NO 0.1%와 산소 2%의 반응가스에 대한 분해 정도를 gas chromatography와 NOx analyzer를 이용하여 측정을 하였다. 촉매 전극의 두께와 소성 온도에 따른 촉매전극의 미세구조가 $NO_x$ 분해에 미치는 영향과 전류량(0.05∼0.6A)에 따른 $NO_x$ 분해율을 측정하였다.

• 한국수소및신에너지학회논문집
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• 제17권3호
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• pp.301-308
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• 2006

The present work explores the effect of carbon-supported platinum catalyst on the HI decomposition using gas adsorption analyzer, thermogravimetry, X-ray diffractometry, scanning electron microscopy, and gas chromatography. For this purpose, three types of activated carbon (C), Pt/C-1 wt.%, and Pt/C-5 wt.% were prepared. The HI gas conversion is crucially influenced by the amount of Pt on the carbon support. The more the amount of Pt was, the higher results in the HI gas conversion. For three types of catalysts, HI conversion increased with increasing the decomposition temperature but with decreasing the space velocity. The increase of HI conversion with temperature was more pronounced in activated carbon than that in Pt/C. From EDX result, it was found that the activated carbon comprised higher amount of iodine than the Pt/C after the decomposition reaction. This implies that the HI conversion is closely related to the amount of Iodine.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.81-85
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• 2007

A fluidized bed reactor is made with quartz. The size of FBR is 0.055 m I.D. and 1.0 m in height. The FBR was employed for the thermocatalytic decomposition of propane to produce hydrogen without $CO_{2}$. The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. Carbon black DCC-N330 is used to decompose the propane gas. The propane decomposition reaction over carbon black catalyst in a fluidized bed reactor was carried out the temperature range of 600 ${\sim}$ 800 $^{\circ}C$, propane gas velocity of 1.0 ${\sim}$ 4.0$U_{mf}$($1U_{mf}$ = 0.61cm/s) and the catalyst loading of 100 ${\sim}$ 200g. Production of $H_{2}$ such as other reaction temperature, gas velocity, catalytic loading on the reaction rates was investigated. The carbon depositied on the catalyst surface was observed by FE-SEM. The particle size of the carbon black was observed by Particle size analyzer. Resulting production in the experiment was not only hydrogen but also several by-products such as methane, ethylene, ethane, and propylene.

• ETRI Journal
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• 제34권5호
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• pp.713-718
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• 2012

Sensor nodes in ubiquitous sensor networks require autonomous replacement of deteriorated gas sensors with reserved sensors, which has led us to develop an encapsulation technique to avoid poisoning the reserved sensors and an autonomous activation technique to replace a deteriorated sensor with a reserved sensor. Encapsulations of $In_2O_3$ nanoparticles with poly(ethylene-co-vinyl alcohol) (EVOH) or polyvinylidene difluoride (PVDF) as gas barrier layers are reported. The EVOH or PVDF films are used for an encapsulation of $In_2O_3$ as a sensing material and are effective in blocking $In_2O_3$ from contacting formaldehyde (HCHO) gas. The activation process of $In_2O_3$ by removing the EVOH through heating is effective. However, the thermal decomposition of the PVDF affects the property of the $In_2O_3$ in terms of the gas reactivity. The response of the sensor to HCHO gas after removing the EVOH is 26%, which is not significantly different with the response of 28% in a reference sample that was not treated at all. We believe that the selection of gas barrier materials for the encapsulation and activation of $In_2O_3$ should be considered because of the ill effect the byproduct of thermal decomposition has on the sensing materials and other thermal properties of the barrier materials.

• 한국분무공학회지
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• 제25권3호
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• pp.132-138
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• 2020

N₂O is hazardous atmosphere pollution matter which can damage the ozone layer and cause green house effect. There are many other nitrogen oxide emission control but N₂O has no its particular method. Preventing further environmental pollution and global warming, it is essential to control N₂O emission from industrial machines. In this study, the thermal decomposition experiment of N₂O gas mixture is conducted by using cylindrical reactor to figure out N₂O reduction and NO formation. And CHEMKIN calculation is conducted to figure out reaction rate and mechanism. Residence time of the N₂O gas in the reactor is set as experimental variable to imitate real SNCR system. As a result, most of the nitrogen components are converted into N2. Reaction rate of the N₂O gas decreases with N₂O emitted concentration. At 800℃ and 900℃, N₂O reduction variance and NO concentration are increased with residence time and temperature. However, at 1000℃, N₂O reduction variance and NO concentration are deceased in 40s due to forward reaction rate diminished and reverse reaction rate appeared.

• 한국응용과학기술학회지
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• 제29권2호
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• pp.268-277
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• 2012

폐 PVC전선의 열적분해 특성에 관한 연구를 TGA 및 고정층 반응기를 이용하여 연구하였다. 본 연구에서는 분해온도, 공기유량 및 CaO/ PVC의 비를 실험조건으로 고려하였으며, PVC전선의 열적분해과정에서 발생되는 염화수소 및 독성가스의 제거를 위한 CaO의 첨가에 대한 효과를 검증하기 위하여 PVC 전선의 열적분해 과정에서 생성되는 기상 생성물을 GC/MS를 이용하여 분석하였다. 또한 CaO의 첨가효과를 고찰하고자 액성 생성물에 대한 GC/MS을 함께 수행하였으며, 분해온도, 공기유량 및 CaO/PVC의 비에 따른 액상, 기상 및 고상 잔류물의 수율 변화를 함께 고찰하였다. 본 연구로부터 CaO의 첨가량이 증가할수록 PVC의 열적분해 과정에서 발생되는 염화수소의 제거량이 증가함을 확인하였다.

• Applied Microscopy
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• 제38권3호
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• pp.259-264
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• 2008

소취 및 소독제로서 사용되어온 안정화 이산화염소($S-ClO_2$)의 조직에 대한 부패억제 효과를 확인하고자 본 연구를 수행하였다. 실험을 위해 8주령 SD계 흰쥐 콩팥(kidney)을 사용하였고, 안정화 이산화염소를 처리하지 않은 대조군과, 안정화 이산화염소의 분말과 수용액을 처리한 실험군으로 구분하여 광학 및 전자현미경으로 관찰하였다. 광학현미경 관찰 결과, 부패양상은 시간경과에 따라 토리, 보우만주머니 및 세뇨관을 구성하는 세포의 핵과 세포사이 경계가 불분명해지며, 세뇨관의 경우 신장되었다가 결국에 수축되었다. 대조군의 1일군부터 괴사(necrosis)가 시작되어 3일군 이후는 전체적인 조직 괴사로 형태를 구별하기 어려웠다. 실험군에서 3일군의 경우, 조직의 전반적 형태와 괴사정도가 대조군의 1일군과 유사하였다. 전자현미경 관찰 결과, 시간경과에 따라 세포소기관 및 미토콘드리아의 부분적 붕괴로 시작되어 결과적으로 모든 세포내소기관이 붕괴되었다. 대조군의 1일군에서 세포소기관의 부분적 붕괴가 관찰되었으며, 실험군의 3일군에서 세포소기관 및 미토콘드리아의 부분적 붕괴 현상이 관찰되었다. 대조군의 3일군 이후에서는 세포소기관을 구별할 수 없었다. 이상의 연구 결과에서 $37^{\circ}C$, 습도 $80{\pm}5%$에서 안정화 이산화염소($S-ClO_2$)가 부패와 변성을 억제하는 부패억제제로서 효과가 있고, 억제 정도는 실험군의 3일군이 대조군의 1일군에 해당하는 것으로 보아 최소 2일 정도의 부패억제 효과가 있는 것으로 확인되었다.