• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.95.1-95.1
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• 2011

In this work, graphene was prepared by modified Hummers method and prepared graphene was applied to electrode materials for supercapacitor. In addition, to enhance the electrochemical performance of graphene, carbon black was deposited onto graphene via chemical reduction. The effect of the carbon black content incorporated on the electrochemical properties of the graphene-based electrodes was investigated. It was found that nano-scaled carbon black aggregates were deposited and dispersed onto the graphene by the chemical reduction of acid treated carbon black and graphite oxide. From the cyclic voltammograms, carbon black-deposited graphene (CB-GR) showed improved electrochemical performance, i.e., current density, quicker response, and better specific capacitance than that of pristine graphene. This indicates that the carbon black deposited onto graphene served as an conductive materials between graphene layers, leading to reducing the contact resistance of graphene and resulted in the increase of the charge transfer between graphene layers by bridge effect.

• 한국환경과학회지
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• 제30권10호
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• pp.863-877
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• 2021

While there a growing interest in Voluntary Carbon Disclosure (VCD), comparatively little is discussed whether the improved quality of voluntary carbon disclosure can lead to subsequent changes in a company's carbon reduction performance. Drawing on companies under the Korean Emission Trading Scheme (ETS) with the contents analysis of their sustainable reports, the present research seeks to address the existing knowledge gaps in the current literature on environmental disclosure. Findings empirically show that an increase in the voluntary carbon disclosure score is positively transformed into changes in carbon performance and further develop that the effect of voluntary carbon disclosure on carbon performance varies depending on changes in management capability with the moderation effect.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권10호
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• pp.2682-2700
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• 2023

To cope with the risks of climate change and promote the realization of carbon peaking and carbon neutrality, this paper first comprehensively considers the policy background, technical trends and carbon reduction paths of energy conservation and emission reduction in data center server industry. Second, we propose a computing power carbon efficiency of data center server, and constructs the carbon emission per performance of server (CEPS) model. According to the model, this paper selects the mainstream data center servers for testing. The result shows that with the improvement of server performance, the total carbon emissions are rising. However, the speed of performance improvement is faster than that of carbon emission, hence the relative carbon emission per unit computing power shows a continuous decreasing trend. Moreover, there are some differences between different products, and it is calculated that the carbon emission per unit performance is 20-60KG when the service life of the server is five years.

• 한국분말재료학회지
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• 제23권6호
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• pp.420-425
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• 2016

N-doped carbon nanofibers as catalysts for oxygen-reduction reactions are synthesized using electrospinning and carbonization. Their morphologies, structures, chemical bonding states, and electrochemical performance are characterized. The optimized N-doped carbon nanofibers exhibit graphitization of carbon nanofibers and an increased nitrogen doping as well as a uniform network structure. In particular, the optimized N-doped carbon nanofibers show outstanding catalytic activity for oxygen-reduction reactions, such as a half-wave potential ($E_{1/2}$) of 0.43 V, kinetic limiting current density of $6.2mAcm^{-2}$, electron reduction pathways (n = 3.1), and excellent long-term stability after 2000 cycles, resulting in a lower $E_{1/2}$ potential degradation of 13 mV. The improvement in the electrochemical performance results from the synergistic effect of the graphitization of carbon nanofibers and the increased amount of nitrogen doping.

• 대기
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• 제19권1호
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• pp.53-66
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• 2009

The purpose of this study is to describe the roles of carbon dioxide in the climate change, and carbon dioxide reduction policies in some countries. In addition, ways to cope with climate change in Korea are also discussed. Currently, global temperatures are rising due to the carbon dioxide produced by human beings. Global temperatures will rise approximately $6^{\circ}C$ until 2100 if we emit carbon dioxide at a present rate. Temperature rise will affect the terrestrial and oceanic resources, and ultimately influence the socio-economic structures including political stability. Most of the carbon dioxide comes from fossil fuels. Therefore, it is urgent to reduce the use of energy, which comes from fossil fuels. Solving the climate change due to the increases in carbon dioxide is a global problem. Korea should participate in the international community and cooperate with each other in order to reduce the carbon dioxide concentration. No policy was announced for the reduction of carbon dioxide so far. Korea should make a policy for the reduction of carbon dioxide in a specific year compared to that of certain standard year such as 1990 or 2005. Making policy should be based on the scientific result of the amount of carbon dioxide emitted and absorbed. Germanwatch announced the Climate Change Performance Index (CCPI) in order to evaluate an effort to reduce the carbon dioxide for 56 countries which emits 90 % of global carbon dioxide. Ranking for Korea is 51 among 56 countries. This clearly indicates that the appropriate carbon dioxide reduction has not been exercised yet in Korea. Researchers have a moral responsibility to provide updated new ideas and knowledges regarding climate change. Politicians should have a sharp insight to judge the ideas provided by researchers. People need an ethics to reduce the carbon dioxide in every day's life. Scientific research should not be influenced by stress caused by external budget and negative impact of capitalism. Science should be based on the pure curiosity.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.133.1-133.1
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• 2010

In this work, carbon black(CBs)-embed multi-walled carbon nanotubes (MWNTs) as conductive fillers for activated carbon(ACs)-based electrodes for supercapacitor were prepared by chemical reduction of oxidized MWNTs and CBs. The effect of CBs-MWNT composites on electrochemical performances of ACs-based electrodes were investigated as a function of CB-MWNT ratio. It was found that CBs-MWNTs composites were formed by the reduction reaction of the functional groups of oxidized MWNTs and CBs. It was resulted in the conjugation of CBs onto the MWNT having high surface area and aspect ratio, leading to the enhanced electrical properties of MWNTs. The electrochemical performances, such as current density, charge-discharge, and specific capacitance of the ACs/CBs-MWNT electrodes were higher than that of ACs/MWNTs and conventional ACs/CB electrodes, which was attributed to the synergistic effect of CBs-MWNTs as a conductive filler.

• 한국재료학회지
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• 제28권3호
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• pp.182-188
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• 2018

Nitrogen (N)-doped protein-based carbon as platinum (Pt) catalyst supports from tofu for oxygen reduction reactions are synthesized using a carbonization and reduction method. We successfully prepare 5 wt% Pt@N-doped protein-based carbon, 10 wt% Pt@N-doped protein-based carbon, and 20 wt% Pt@N-doped protein-based carbon. The morphology and structure of the samples are characterized by field emission scanning electron microscopy and transmission electron micro scopy, and crystllinities and chemical bonding are identified using X-ray diffraction and X-ray photoelectron spectroscopy. The oxygen reduction reaction are measured using a linear sweep voltammogram and cyclic voltammetry. Among the samples, 10 wt% Pt@N-doped protein-based carbon exhibits exellent electrochemical performance with a high onset potential of 0.62 V, a high $E_{1/2}$ of 0.55 V, and a low ${\Delta}E_{1/2}=0.32mV$. Specifically, as compared to the commercial Pt/C, the 10 wt% Pt@N-doped protein-based carbon had a similar oxygen reduction reaction perfomance and improved electrochemical stability.

• Carbon letters
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• 제4권3호
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• pp.121-125
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• 2003

The Pt-Ru/Carbon as an anode catalyst supported on the commercial activated carbon (AC) having high surface area and micropore was characterized for application of Direct Methanol Fuel Cell (DMFC). The Pt-Ru/AC anode catalyst used in this experiment showed the performance of $600\;mA/cm^2$ current density at 0.3 V. The borohydride reduction process using $NaBH_4$, denoted as a process A, showed much higher current and power densities than process B prepared by changing the reduction and washing process of process A. The particle sizes are strongly affected by the reduction process than the specific surface area of raw active carbon and the sizes are almost constant when the specific surface area of carbon are over than the $1200\;m^2/g$. Smaller particle size of catalyst and more narrow intercrystalite distance increased the performance of DMFC.

• 대한화학회지
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• 제68권2호
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• pp.87-92
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• 2024

The commercialization of rechargeable metal-air batteries is extremely desirable but designing stable oxygen reduction reaction (ORR) catalysts with non-noble metal still has faced challenges to replace platinum-based catalysts. The nonnoble metal catalysts for ORR were prepared to improve the catalytic performance and stability by the thermal decomposition of ZIF-8 with optimum cobalt loading. The porous carbon was obtained by the calcination of ZIF-8 and different loading amounts of Co nanoparticles were anchored onto porous carbon forming a Co/PC catalyst. Co/PC composite shows a significant increase in the ORR value of current and stability (500 h) due to the good electronic conductive PCN support and optimum cobalt metal loading. The significantly improved catalytic performance is ascribed to the chemical structure, synergistic effects, porous carbon networks, and rich active sites. This method develops a new pathway for a highly active and advantageous catalyst for electrochemical devices.

• 한국철도학회논문집
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• 제20권3호
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• pp.382-388
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• 2017

지구온난화로 인한 범세계적 위기가 초래됨에 따라 1997년 선진국을 중심으로 교토의정서가 체결되었고 2015년 개발도상국까지 공동의무를 부과하는 파리협정이 체결되어 이를 계기로 온실가스 감축 규제 및 국가적 노력이 본격화 되고 있다. 본 연구에서는 한국철도시설공단에서 효율적인 철도건설을 위해 전통적인 건설사업관리 업무를 전산화함에 따라 저감되는 탄소배출량을 분석하였다. 이를 위해 '방문감소에 의한 탄소발생 저감'과 '종이감소에 의한 탄소발생 저감'효과를 측정하는 산출모델을 제시하고자 한다. 수립된 산출모델을 활용하여 건설사업관리시스템 도입에 따른 탄소저감량을 산출하고 이를 경제적 비용으로 환산한다. 본 연구에서 제시한 산출모델 및 산출방식은 정보화사업 추진으로 인한 탄소저감 효과를 분석하는데 도움이 될 수 있을 것으로 기대된다.