• 한국농공학회논문집
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• 제65권3호
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• pp.1-13
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• 2023

Local governments play a critical role in achieving carbon neutrality and reducing national carbon emissions. To manage carbon emissions effectively, it is essential for local governments to analyze regional carbon emissions. In this study, we developed a model for estimating carbon emissions based on land use and analyzed regional characteristics of carbon emissions to suggest policies for achieving carbon neutrality at the regional level. Our model for calculating carbon emissions is based on an analysis of the activities that contribute to carbon emissions for each land use, and we established the spatial scope of carbon emission calculation. We applied this model to the cities and counties in Gyeongsangnam province, calculating carbon emissions from settlement and agricultural production activities and comparing regional characteristics of carbon emissions. Our analysis showed that areas with larger populations generally produced higher emissions in all categories, but we observed different results in terms of unit emissions, emissions divided by area, population, and household. Based on these findings, we propose policies such as increasing the generation of new and renewable energy using public institutions, promoting the conversion to cleaner cooking and heating energy sources, and encouraging the adoption of eco-friendly automobiles on roads. We believe that our analysis of the spatial and regional characteristics of carbon emissions can help local governments establish effective policies for reducing carbon emissions in their regions.

• 분석과학
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• 제27권6호
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• pp.308-313
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• 2014

염료감응형 태양전지의 광전극 및 상대전극에 탄소나노튜브를 도입하여 전지의 광전기적 특성 변화를 EIS, J-V 특성곡선 및 UV-Vis 분광기를 이용하여 분석하였다. $TiO_2$ 광전극의 전기전도도 및 광전효율을 향상시키기 위해 전자전달 촉진자 역할을 하는 multi-wall carbon nanotube (MWCNT)를 $TiO_2$와 혼합하여 $TiO_2$-MWCNT 복합체를 sol-gel 연소 복합공정을 통해 제조하여 조사한 결과 0.1 wt% MWCNT를 첨가한 경우, $TiO_2$만을 사용한 경우에 비해 약 12.5%의 향상된 효율을 보였다. $TiO_2$-MWCNT 복합체에서 MWCNT가 $TiO_2$ 층의 전자이동을 향상시켜 저항을 감소하고 염료와 전자의 재결합을 감소시킨 결과로 생각된다. 그러나 0.1 wt%보다 많은 MWCNT를 첨가할 경우 광투과도 및 염료의 흡착량을 감소시켜 효율이 감소하였다. 또한 상대전극에 MWCNT와 MWCNT-Pt를 적용하였을 경우 각각의 효율은 1.2%와 4.1%로 MWCNT만 적용할 때 보다 백금이 담지된 MWCNT를 사용하였을 경우에 백금과 비슷한 효율을 보였다.

• 한국분말재료학회지
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• 제14권1호
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• pp.44-49
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• 2007

In the fabrication of dye-sensitized solar cells (DSSCs), carbon counter electrode has been tested for replacing the platinum counter electrode which has two drawbacks: limited surface area and high material cost. Poor mechanical stability of carbon layer due to weak bonding strength to electrically conductive TCO (transparent conducting oxide) glass substrate is a crucial barrier for practical application of carbon counter electrode. In the present study a carbon counter electrode with high conversion efficiency, comparable to Pt counter electrode, could be fabricated by adaption of a bonding layer between particulate carbon material and TCO substrate.

• 한국세라믹학회지
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• 제37권4호
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• pp.376-380
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• 2000

Carbon nanofibers with an average diameter of 100nm were reacted with SiO vapor generated from a mixture of Si and SiO2 to produce silicon carbide nanofibers at temperature ranging 1200∼1500$^{\circ}C$ under vacuum. The nanofiber reacted at 1200$^{\circ}C$ for two hours consisted of silicon carbide with an average crystallite size of 10-20nm, amorphous silica and a significant amount of unreacted carbon. The surface area of silicon carbide nanofiber, obtained after removal of amorphous silica and unreacted carbon from converted carbon nanofibers at 1200$^{\circ}C$, was as high as 150㎡/g. With increasing reaction temperature to 1500$^{\circ}C$, the surface area was decreased to 14㎡/g. Growth of SiC crystallite size with increasing conversion temperature of carbon nanofiber was confirmed from Scherrer formula using the (111) diffraction line and TEM images of converted carbon nanofibers.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.514-518
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• 2018

The direct carbon fuel cell (DCFC) has attracted researcher's attention recently, due to its high conversion efficiency and its abundant fuel, carbon. A DCFC mathematical model has developed in two-dimensional, lab-scale, and considers Boudouard reaction and carbon monoxide (CO) oxidation. The model simulates the CO production by Boudouard reaction and additional electron production by CO oxidation. The Boudouard equilibrium strongly depends on operating temperature and affects the amount of produced CO and consequentially affects the overall fuel cell performance. Two different operating temperatures (973 K, 1023 K) has been calculated to discover the CO production by Boudouard reaction and overall fuel cell performance. Moreover, anode thickness of the cell has been considered to find out the influence of the Boudouard reaction zone in fuel cell performance. It was found that in high temperature operating DCFC modeling, the Boudouard reaction cannot be neglected and has a vital role in the overall fuel cell performance.

• Korean Chemical Engineering Research
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• 제47권6호
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• pp.700-704
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• 2009

GTL(gas-to-liquid) 합성유 제조용 SCR(steam carbon dioxide reforming) 공정의 시뮬레이션 연구를 수행하였다. 온도 및 $CH_4/steam/CO_2$ 반응물 비와 같은 변수를 바꾸어 가면서 SCR 공정을 위한 최적 운전조건을 살펴보았다. 공정 시뮬레이션을 위해 Aspen Plus를 사용하였다. 또한 정상상태 가정하의 열역학적 물성치 계산을 위해 Aspen Plus의 RSK (Redlich-Kwong-Soave) 상태방정식을 사용하였다. FT 공정을 위한$H_2/CO$ 비, $CH_4$ 전환율, $CO_2$ 전환율을 살펴봄으로써 최적의 온도와 최적의 반응물 비를 결정하였다. 시뮬레이션 결과, SCR reformer 촉매층 출구 최적온도는 상압에서 $850^{\circ}C$ 였으며, 이 온도에서 $CH_4$ 전환율은 99%, $CO_2$ 전환율은 49%로 계산되었고, $CH_4/steam/CO_2$ 최적 반응물 비율은 1.0/1.6/0.7로 나타났다.

• 공업화학
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• 제31권3호
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• pp.323-327
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• 2020

이산화탄소 메탄화 공정 적용을 위해 저온에서 우수한 활성을 나타내는 Ni/CeO_2-X의 반응 특성을 조사하였다. 지지체인 CeO_2-X는 Ce(NO₃)₃를 400 ℃에서 열처리하여 획득하였으며, 촉매는 함침법으로 제조되었다. 실험의 운전 변수로써 반응기 내부 압력, 유입가스 중 산소, 메탄, 황화수소의 조성 및 반응 온도에 대하여 수행하였다. Ni/CeO_2-X를 이용한 이산화탄소 메탄화 반응에서 압력이 1 bar에서 3 bar로 증가함에 따라 CO₂ 전환율은 25% 이상 증가하였으며, 낮은 반응 온도에서 증가폭이 크게 나타났다. 유입가스 중 산소와 메탄은 촉매의 CO₂ 전환율을 최대 16, 4%씩 감소시켰으며, 산소와 메탄의 농도가 높아질수록 CO₂ 전환율의 감소율이 증가하는 경향을 나타내었다. 또한 황화수소는 촉매의 CO₂ 전환율을 최대 7% 감소시켰으며 촉매의 비활성화를 야기하였다. 본 연구의 결과들은 이산화탄소의 메탄화 공정 기초 자료로 유용하게 사용될 수 있을 것이다.

• 상하수도학회지
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• 제34권6호
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• pp.437-443
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• 2020

Biological phosphorus removal is accomplished by exposing PAO(phosphorus accumulating organisms) to anaerobic-aerobic conversion conditions. In the anaerobic condition, PAO synthesize PHB(polyhydroxybutyrate) and simultaneously hydrolysis of poly-p resulting phosphorus(Pi) release. In aerobic condition, PAO uptake phosphorus(Pi) more than they have released. In this study, cyanobacteria Synechococcus sp., which is known to be able to synthesize PHB like PAO, was exposed to anaerobic-aerobic conversion. If Synechococcus sp. can remove excess phosphorus by the same mechanism as PAO, synergistic effects can occur through photosynthesis. Moreover, Synechococcus sp. is known to be capable of synthesizing PHB using inorganic carbon as well as organic carbon, so even if the available capacity of organic carbon decreases, it was expected to show stable phosphorus removal efficiency. In 6 hours of anaerobic condition, phosphorus release occurred in both inorganic and organic carbon conditions but SPRR(specific phosphorus release rate) of both conditions was 10 mg-P/g-MLSS/day, which was significantly lower than that of PAO. When converting to aerobic conditions, SPUR(specific phosphorus uptake rate) was about 9 mg-P/g-MLSS/day in both conditions, showing a higher uptake rate than the control condition showing SPUR of 6.4 mg-P/g-MLSS/day. But there was no difference in terms of the total amount of removal. According to this study, at least, it seems to be inappropriate to apply Synechococcus sp. to luxury uptake process for phosphorus removal.

• The Korean Journal of Ecology
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• 제27권4호
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• pp.217-224
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• 2004

The purpose of this study is to clarify the effects of the conversion of the forest management type from a natural deciduous broad-leaved forest to an artificial evergreen coniferous forest based on organic matter dynamics. We investigated the amounts and carbon contents of the forest floor and the litterfall, soil chemical characteristics and cellulose decomposition rates in the natural deciduous broad-leaved forest and adjacent artificial evergreen coniferous forest. In the artificial evergreen coniferous forest were planted Japanese cypress (Chamaecyparis obtusa) on the upper slope and Japanese cedar (Cryptomeria japonica) on the lower slope. The soil carbon and nitrogen contents, CEC and microbial activity had decreased due to the conversion of the forest management type from a natural deciduous broad-leaved forest to an artificial Japanese cypress forest, and were almost the same for the conversion to a Japanese cedar forest. Under the same conditions, it is considered that the soil fertility was different by planting specific tree species because the organic matter dynamics were changed by them.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.120-124
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• 2010

Monometallic, bimetallic and trimetallic particles consisting of different weight compositions of Pt-Pd-Rh over pure alumina wash coats have been synthesized and their catalytic performance on methane conversion was studied from 150 to $600^{\circ}C$. Different catalyst formulations with variable Pt, Pd and Rh contents for bimetallic and trimetallic systems were tried and $Pt_{(1.5)}Rh_{(0.3)}/Al_2O_3$ and $Pt_{(1.0)}Pd_{(1.0)}Rh_{(0.3)}/Al_2O_3$ shows low $T_{50}$ and $T_{90}$ temperatures. Bimetallic and trimetallic particle synergism acts as three way catalysts and therefore, all the catalysts show 100% methane conversion. The effect of supports such as $ZrO_2$ and $TiO_2$ on methane combustion was investigated; from $T_{50}$ and $T_{90}$ results both $Al_2O_3$ and $ZrO_2$ are suitable supports for low temperature methane combustion.