• Carbon letters
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• 제3권4호
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• pp.192-197
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• 2002

Microstructure plays an important role in controlling the fracture behaviour of carbon-carbon composites and hence their mechanical properties. In the present study effort was made to understand how the different interfaces (fiber/matrix interactions) influence the development of microstructure of the matrix as well as that of carbon fibers as the heat treatment temperature of the carbon-carbon composites is raised. Three different grades of PAN based carbon fibres were selected to offer different surface characteristics. It is observed that in case of high-strength carbon fiber based carbon-carbon composites, not only the matrix microstructure is different but the texture of carbon fiber changes from isotropic to anisotropic after HTT to $2600^{\circ}C$. However, in case of intermediate and high modulus carbon fiber based carbon-carbon composites, the carbon fiber texture remains nearly isotropic at $2600^{\circ}C$ because of relatively weak fiber-matrix interactions.

• Carbon letters
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• 제4권1호
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• pp.24-30
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• 2003

In this study, densified 4D carbon/carbon composites were made from carbon fiber and coal tar pitch through the process of pressure impregnation and carbonization and then followed by carbonization and graphitization. To improve the oxidative resistance of the prepared carbon/carbon composites, the surface of carbon/carbon composites was coated on SiC by the pack cementation method. The SiC coated layer was created by depending on the constitution of pack powder, and reaction time of pack-cementation. The morpology of crystalline and texture of these SiC coated carbon/carbon composites were investigated by XRD, SEM/EDS observation. So the coating mechanism of pack-cementation process was proposed. The oxidative res istance were observed through the air oxidation test, and then the optimal condition of pack cementation was found by them. Besides, the oxidative mechanism of SiC formed was proposed through the observation of SiC coated surface, which was undergone by oxidation test.

• Carbon letters
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• 제5권2호
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• pp.62-67
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• 2004

Performance of carbon-carbon composites is known to be influenced by the fibre matrix interactions. The present investigation was undertaken to ascertain the development of microstructure in such composites when carbon fibres possessing different surface energies (T-300, HM-35, P120 and Dialed 1370) and pitch matrices with different characteristics (Coal tar pitch $SP110^{\circ}C$ and mesophase pitch $SP285^{\circ}C$) are used as precursor materials. These composites were subjected to two different heat treatment temperatures of $1000^{\circ}C$ and $2600^{\circ}C$. Quite interesting changes in the crystalline parameters as well as the matrix microstructure are observed and attempt has been made to correlate these observations with the fibre matrix interactions.

• Carbon letters
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• 제5권3호
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• pp.127-132
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• 2004

Chop molding composites and 2D carbon/carbon composites were manufactured by hot press molding method. Phenol resin of novolac type was used for matrix precursor and PAN-based carbon, PAN-based graphite and pitch-based carbon fiber were used for reinforcement and boron oxide was used for oxidation retardant. All of the composites were treated by $2000^{\circ}C$ and $2400^{\circ}C$ graphitization process, respectively. After graphitization process, amount of a boron residue in carbon/carbon composites is much according to irregularity of used raw materials. Under the presence of boron in carbon/carbon composites, catalytic effect of boron was a little at $2000^{\circ}C$ graphitization temperature. However, it was quite at $2400^{\circ}C$ graphitization.

• Carbon letters
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• 제28권
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• pp.100-104
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• 2018

• Carbon letters
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• 제6권3호
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• pp.148-157
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• 2005

Carbon/Carbon Composites due to their far superior thermo-mechanical properties are used in a number of demanding applications. However, the material still is used only in specific high tech applications with few exceptions in general industrial applications. The material is extremely expensive and the major challenge is to reduce its cost. Various innovative processing routes are outlined to reduce the cost of processing.

• 한국세라믹학회지
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• 제40권12호
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• pp.1150-1153
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• 2003

Carbon nanofilaments were formed on silicon substrate using microwave plasma-enhanced chemical vapor deposition method. The structures of carbon nanofilaments were identified as carbon nanotubes or carbon nanofibers. The formation of bamboo-like carbon nanotubes was initiated by the application of the bias voltage during the plasma reaction. The growth kinetics of bamboo-like carbon nanotubes increased with increasing the bias voltage. The growth direction of bamboo-like carbon nanotubes was vertical to the substrate.

• 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.

• 한국안전학회지
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• 제27권3호
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• pp.182-188
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• 2012

In this study we analyzed carbon emissions of leaves of a Pinus densiflora which is vulnerable to a forest fire using the cone calorimeter in order to analyze greenhouse gas emissions from forest fires depending on region and altitude. Fuels were collected from 9 regions[Hongcheon(Gangwon-do), Chungsong(Gyeongbuk-do), Yanhpyeong (Gyeonggi-do), Jecheon(Chungchongbuk-do), Gongju(Chungcheongnam-do), Wuju(Jeollabuk-do), Youngam(Jeollanam-do), Busan and Jeju-do)] and 9 altitudes(80 m, 450 m, 900 m, 1000 m, 1100 m, 1200 m, 1300 m, 1400 m and 1500 m) and then, carbon dioxide and carbon monoxide emissions contained in a weight of 50 g of fuel were analyzed. According to the results, there were differences in carbon emissions by regional groups, as the average carbon dioxide and carbon monoxide emissions in 9 regions were nearly 43.5929 g to 52.8868 g, and 0.8842 g to 3.6422 g, respectively. Busan and Jecheon had relatively higher carbon dioxide emissions and especially, Busan had 1.23 times higher carbon dioxide emissions than Jeju-do. Also, Gongju, Chungcheongnamo Province and Busan had relatively higher carbon monoxide emissions and especially, Gongju and Pusan had relatively higher carbon monoxide emissions and especially, Gongju had 4.12 higher carbon monoxide emissions than Hongcheon. In addition, there were differences in carbon emissions too depending on altitude, since carbon dioxide and carbon monoxide emissions in 9 altitudes were respectively, 40.7015 g to 68.9297 g and 1.3923 g to 12.2918 g. At the altitude of 80m, carbon dioxide and carbon monoxide emissions were respectively, 68.9297 g and 12.2918 g, and at the altitude of 450m, carbon dioxide and carbon monoxide emissions were respectively, 65.5115 g and 11.2497 g. These results show that pine trees at the lower altitude discharge relatively more carbon. It is considered that this analysis on carbon emissions depending on region and altitude can be effectively used for predicting greenhouse gas emissions and establishing statistical data from forest fires in each region and altitude.

• 한국산업정보학회논문지
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• 제28권6호
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• pp.115-129
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• 2023

본 연구는 탄소가격 수준을 나타내는 CPS를 통해 국내외 탄소가격을 비교분석하여, 탄소세 도입의 필요성을 검토한다. 분석결과, 탄소세 시행국의 탄소집약도가 미시행보다 낮게 나타났다. 탄소세 도입이 에너지효율성을 높이며 탄소배출을 낮추는데 도움이 될 것으로 예상된다. 탄소중립을 위해 요구되는 수준으로 탄소가격이 상승할수록 국내 CPS가 큰 폭으로 하락했으며, 가정 및 상업부문에서 하락 폭이 크게 나타났다. 따라서 탄소중립에 필요한 탄소가격 수준에 이르기 위해 국내에 탄소세 도입이 필요하며, 특히 가정 및 상업부문에 우선적으로 탄소세 도입할 필요가 있다. 또한, 탄소세를 도입하더라도 일정 수준 이상이어야 탄소집약도 개선효과가 유의하게 나타날 것으로 보인다.