• KSBB Journal
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• v.17 no.2
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• pp.148-152
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• 2002

The extraction of volatile essential oil using supercritical carbon dioxide with 2%(v/v) ethanol and non-ethanol was performed in a semi-continuous flow extractor at the range of pressures and temperatures 6.9 to 17.2 MPa and 30 to 45$^{\circ}C$, respectively. When ethanol was added to the co-solvent, the solubility of volatile essential oils was increased up to 90% over the neat CO$_2$ value. The most efficiency of extraction of the voilatile essential oils was achieved at 13.8㎫ and 40$^{\circ}C$ by supercritical carbon dioxide with entrainer from Citrus junos peel.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.165-171
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• 1999

Diamond-like carbon(DLC) films were synthesized using the rf-plasma CVD technique with the addition of small amounts of nitrogen and oxygen to a gas mixture of $CH_4$ and $H_2$. The gas flow ratio of $CH_4$ to $H_2$ was 2.4:1, and 3% , 13.6% of nitrogen were added to the gas mixture of $CH_4$ and $H_2$ for the deposition of DLC films. The film stress tended to decrease as the nitrogen concentration increased from 3% to 13.6%, probably due to the decrease of the number of the interlink between carbon atoms. The residual stress tended to slightly decrease when 3% of oxygen was added. Scratch tests were performed to investigate the adhesion between the DLC films and the Ti intelayer after pretreating the TiN surface with direct hydrogen plasma. The adhesion was enhanced by adding nitrogen and oxygen to the $CH_4$ and $H_2$ gas mixture. The adhesion for the 3% nitrogen addition was better than that for the 13.6% nitrogen addition. The Vicker's hardness of the DLC films was measured to be 1100Hv.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.2
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• pp.146-158
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• 2021

We are to introduce an example of ESD in connection with SDGs through liberal arts courses opened at the College of Education. We analyzed the awareness of the carbon footprint expressed by 42 preservice teachers in a class designed in connection with SDGs 13 goal, 'climate action'. The pre-service teachers wrote a carbon diet diary, a checklist for the level of practice that emits carbon in daily life, and freely expressed the source and proportion of their carbon emissions through the carbon footprint drawing activity. In items of electricity use, public transportation use, and garbage disposal, the level of practice was positive, but water use was analyzed in a negative way. The pre-service teachers who expressed the carbon footprint in 2-3 items reached a majority, showing limitations in recognizing the carbon emission situation in their daily life. Pre-service teachers will be the main actors of education on the environmental issues of the earth at the school site, and the carbon literacy of pre-service teachers will directly or indirectly affect students. We hope that various ESD programs linked to the 17 SDGs will be developed and applied to the educational field to contribute to sustainable global environmental education.

• Land and Housing Review
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• v.10 no.1
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• pp.19-23
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• 2019

In recent years, many studies have been conducted on smart low carbon cities through the fusion of ICT information technology for the purpose of reducing carbon. In this study, we investigated 13 cities in three continents that implement low-carbon city policies and analyzed the size, economic and social characteristics of each city to identify the degree of dynamic mechanism for carbon reduction. To this end, we quantified the elements of the city and analyzed the basic requirements for low-carbon cities using the TOPSIS method. The study found that most cities were better able to activate institutions and cultural conditions, facilities and functional conditions, and economic and industrial conditions than other engines, and these three were the main forms of power for smart low carbon cities. The results of this study are expected to be used as a basis for suggesting policy recommendations and improvement measures for future smart low carbon cities.

• Korea Trade Review
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• v.47 no.1
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• pp.99-114
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• 2022

This paper analyzed the dynamic conditional correlation between the carbon emission trading prices of Korea, China, EU, New Zealand. This paper was analyzed using the daily data of carbon emission trading prices of each country from January 12, 2015 to January 13, 2021 using the DCC-GARCH model. Summarizing the research results, first, the dynamic conditional correlation between carbon emission trading prices in the EU, Korea, and China, excluding New Zealand, was strong, indicating that there was a co-movement phenomenon. Second, it was found that carbon emission trading prices in major countries have a stronger tendency to co-movement due to global shocks. Third, it appears that the dynamic conditional correlation between the carbon emission trading prices of Korea and China is gradually strengthening. This study confirmed that the co-movement between carbon emission trading prices in Korea and other countries gradually intensified as time passed. In particular, it is meaningful in suggesting the implication that the phenomenon of co-movement between carbon emission trading prices in Korea and China is gradually intensifying.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.1
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• pp.1-13
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• 2024

Hydrogen is emerging as an essential material for carbon neutrality. In particular, Korea needs 22.9 million tons of imported clean hydrogen by 2050 to achieve carbon neutrality. However, a large amount of carbon is emitted during the import process, and market regulations are being discussed. This research estimates the carbon emissions of importing green hydrogen from Vietnam, Australia, and the United Arab Emirates to Korea, and calculates imported green hydrogen prices under carbon emission market regulations.

• Journal of the Korean Society of Systems Engineering
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• v.13 no.2
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• pp.65-74
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• 2017

Supercritical carbon dioxide power system is the next generation electricity technology expected to be highly developed. The power system can improve net efficiency, simplify cycle configuration, and downsize equipment compared to conventional steam power system. In order to dominate the new market in advance, it is required to found Front End Engineering Design (FEED) Framework of the system. Therefore, this study developed the FEED framework including design processes for the supercritical carbon dioxide power system, information elements for each process, and relationships for each element. The developed FEED framework is expected to be able to secure systematic technological capabilities by establishing a common understanding and perspective among multi-field engineers participating in the design.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.194-200
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• 2001

In this study, the optical properties of diamond-like carbon(DLC) films, which was synthesized by 13.56 MHz rf plasma enhanced chemical vapor deposition system(PECVD), were investigated. We observed the variation of the transmittance and optical band gap with respect to deposition condition. The change of the transmittance and optical band gap of the DLC films were investigated as a function of RF power, working pressure, and additional gas. The optical band gap decreased with the increase of RF power and working pressure. We could verify the bond structures change of DLC films by observing the content of hydrogen using FT-IR spectroscopy. And the addition of hydrogen and nitrogen decreased the optical band gap by the breakage of C-H bond of DLC films during the deposition.

• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.503-507
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• 2004

We prepared EM wave absorbers by using recycled Sr ferrite for GHz frequency, and investigated the effects of carbon additions and preparation temperatures on their EM wave absorption properties. A Sr ferrite EM wave absorber with the ratio of Sr ferrite: silicon rubber: carbon = 80 : 13.6: 6.4 wt% prepared at 7$0^{\circ}C$ showed -24 dB at 9.4 GHz and -23 dB at 5.5 GHz for 2 mm and 3 mm thickness, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.4
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• pp.13-23
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• 2003

Organic carbon and nitrogen contents in suspended particulate matter (SPM) and surface sediments in seawater were measured in the Northern East China Sea in summer. The distribution of particulate organic carbon(POC) and particulate organic nitrogen(PON) were in the ranges of 54~481㎍/ℓ and 6~85㎍/ℓ, respectively, with relatively high level of concentrations in the western and southern sides of the study area. Also, there has been a significantly positive correlation between POC and PON, gradually increasing toward the deeper range of depth. Average C:N ratios of POC and PON of SPM were 6 in study area. The ratios of POC to PON of SPM increased as the range of depth increased, indicating nitrogen decomposes more rapidly than carbon and is considered to be influenced by the input of detritus from surface sediments. The distribution of total organic matter(TOM), total organic carbon(TOC) and total organic nitrogen(TON) in surface sediments were in the ranges of 3.1~9.6%, 0.282~0.635% and 0.022~0.069%, respectively, with relatively low range in the western and northern sides of the study area. The ratio of TOC to TON of surface sediments were in the range of 9.8~17.4(average of 13), strongly indicating the active role of the input from the terrestrial organic pollutants.