• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1330-1336
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• 2008

Here we studied the changes on quality characteristics of Dongchimi by supercritical carbon dioxide to manufacture Dongchimi of high quality. There were no distinctive changes of acidity, pH, color difference, free sugar and organic acid of the Dongchimi treated with supercritical $CO_2$, compared to the control. The content of vitamin C in Dongchimi, which was treated with supercritical $CO_2$ (at 25 MPa, $35^{\circ}C$) was 0.826 mg/mL, and was similar to that of 0.1 MPa. Unpleasant volatile compounds such as dimethyl disulfide, metyl trisulfide and methyl propyl disulfide in Dongchimi were decreased by supercritical $CO_2$; also, treatment of supercritical $CO_2$ was useful to improve flavor of Dongchimi. Polygalacturonase activity was decreased 40.3% after supercritical carbon dioxide treatment at 25 MPa and $55^{\circ}C$.

• KSBB Journal
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• v.29 no.3
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• pp.155-164
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• 2014

Succinic acid, a representative biomass-derived platform chemical, is a major fermentation product of Actinobacillus succinogenes. It is well known that carbon dioxide is consumed during the succinate fermentation, but the biochemical mechanism behind this phenomenon is not yet understood well. In this study, it was found that the addition of carbonic anhydrase (CA)s into media significantly enhances the succinic acid production by A. succinogenes during the fermentation supplied with carbon dioxide. It is likely that the (bi) carbonate produced by the CA activity from gaseous carbon dioxide is favoured by A. succinogenes for consumption and utilization. Therefore, the $MgCO_3$ requirement could be significantly reduced without compromising the succinate productivity. Furthermore, because of too high price of the commercial carbonic anhydrase, it was undertaken to economically overproduce a cyanobacterial carbonic anhydrase by the use of a recombinant Pichia pastoris. An expression vector system was constructed with the carbonic anhydrase gene PCR-cloned from Cyanobacterium Synechocystis sp., and introduced into P. pastoris for fermentation studies. About 95.9 g/L of succinic acid was produced in the production medium with 30 ppm of carbonic anhydrase, approximately 2 fold higher productivity compared to the parallel process with no supplementation of the enzyme. It is expected that this method can provide a valuable way of overcoming inefficiencies inherent in gas supply during $CO_2$-based bioprocesses like succinic acid fermentation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.259-268
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• 2012

This paper aims to estimate the carbon dioxide stocks in forests using airborne LiDAR data with a density of approximate 4.4 points per meter square. To achieve this goal, a processing chain consisting of bare earth Digital Terrain Model(DTM) extraction and individual tree top detection has been developed. As results of this experiment, the reliable DTM with type-II errors of 3.32% and tree positions with overall accuracy of 66.26% were extracted in the study area. The total estimated carbon dioxide stocks in the study area using extracted 3-D forests structures well suited with the traditional method by field measurements upto 7.2% error level. This results showed that LiDAR technology is highly valuable for replacing the existing forest resources inventory.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.207-212
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• 2001

Supercritical fluid extraction was explored as a method for removing lipids and bad odor from tuna viscera. Selected conditions of extraction pressure, time, temperature and sample size were evaluated for effective removal of lipids and bad odor, Supercritical carbon dioxide was used as a solvent and the extraction was performed at semi-batch flow type. The experimental conditions used in this work was the range of pressure from 1,500 psig to 2,000 psig, the temperature from $25^{\circ}C\;to\;40^{\circ}C$ and dried sample size from 0.2 mm to 1.0 mm. The main fatty acids extracted from tuna viscera were palmitic acid (16: 0) heptadecenoic acid (17: 1) oleic acid (18: 1) and docosahexaenoic acid (22: 6). Protein concentrate was obtained without deformation the optimum condition at $35^{\circ}C$, 1,800 psig and 0.25 mm of the size. In the concentrate after supercritical carbon dioxide extraction, the major amino acids were glutamic acid, leucine and lysine.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.97-104
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• 2013

Methyl alcohol is one of the basic intermediates in the chemical industry and is also being used as a fuel additive and as a clean burning fuel. In this study, conversion of carbon dioxide to methyl alcohol was investigated using catalytic chemical methods. Ceramic monoliths (M) with $400cell/in^2$ were used as catalyst supports. Monolith-supported CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using ICP analysis, TEM images and XRD patterns. The catalytic activity for carbon dioxide hydrogenation to methyl alcohol was investigated using a flow-type reactor under various reaction temperature, pressure and contact time. In the preparation of monolith-supported CuO-ZnO catalysts by wash-coat method, proper concentration of precursors solution was 25.7% (w/v). The mixed crystal of CuO and ZnO was well supported on monolith. And it was known that more CuO component may be supported than ZnO component. Conversion of carbon dioxide was increased with increasing reaction temperature, but methyl alcohol selectivity was decreased. Optimum reaction temperature was about $250^{\circ}C$ under 20 atm because of the reverse water gas shift reaction. Maximum yield of methyl alcohol over CuO-ZnO/M catalyst was 5.1 mol% at $250^{\circ}C$ and 20 atm.

• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.165-175
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• 2021

Purpose: The purpose of this study is to quantitatively present the carbon dioxide(CO₂) emission change according to the application of autonomous driving technology at the network level for waste vehicles in the metropolitan area. Method: The target year was set to 2030, and the analysis method estimated the carbon dioxide (CO₂) emissions for each road link through user equilibrium assignment when unapplied scenario. The application scenario performed traffic assignment using route data on the premise that the group was running in accordance with the application of autonomous driving technology to waste vehicles. In addition, the other means estimated the carbon dioxide emissions through user balance allocation by reflecting the results of the waste vehicle allocation. Result: As a result of the analysis, carbon dioxide(CO₂) emissions were found to be reduced by about 56.9ton/day from the national network level, and the Seoul metropolitan area was analyzed to be reduced by about 54.7ton/day. Conclusion: This study quantitatively presented environmental impacts among various social effects that autonomous driving technology will bring, and in the future, development of various analytical methodologies and related studies should be continuously conducted.

• Clean Technology
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• v.11 no.3
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• pp.147-152
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• 2005

For estblishing the best technique for the micronization of Ibuprofen using supercritical fluids, the solubility should be known. The solubility of Ibuprofen in supercritical carbon dioxide was measured by observing the cloud point. The cloud point was observed using high pressure equipment equipped a variable volume view cell between temperature of 35, 40 and $45^{\circ}C$. The solubility data was correlated by the Peng-Robinson equation of state Solute physical properties, such as critical temperature (Tc), critical pressure (Pc) and acentric factor (${\omega}$) were estimated by the some group contribution method. As pressure was increased, the solubility increased at constant temperature. The retrograde phenomenon by a solute vapor pressure and a density of solvent was observed at the pressure of around 150bar. It was found that $CO_2$ can be used as a supercritical solvent in micronization of ibuprofen by RESS.

• Journal of the Korean Applied Science and Technology
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• v.18 no.3
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• pp.167-173
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• 2001

The spinel $LiMn_{2}O_{4}$ powders were synthesized at $480^{\circ}C$ for 12 h in air by a sol-gel method using manganese acetate and lithium hydroxide as starting material and the $Fe_{3}O_{4}$ powders were synthesized by the precipitation method using $0.2M-FeSO_{4}{\cdot}H_{2}O$ and 0.5M-NaOH. The synthesized $Fe_{3}O_{4}$ powders were mixed at portion of 5, 10, 15 and 20 wt% about $LiMn_{2}O_{4}$ powders through ball-milling followed by drying at room temperature for 48 h in air. The mixed catalysts were reduced at $350^{\circ}C$ for 3 h by hydrogen and the decomposition rate of carbon dioxide was measured at $350^{\circ}C$ using the reduced catalysts. As the results of $CO_{2}$ decomposition experiments, the decomposition rates of carbon dioxide were 85% in all catalysts but the initial decomposition rates of $CO_{2}$ were slightly high in the case of the $5%-Fe_{3}O_{4}$ added catalyst.

• Applied Biological Chemistry
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• v.33 no.3
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• pp.257-260
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• 1990

The weight increasing rate of soda lime, absorbing carbon $dioxide(CO_2)$ generated during fermentation at $25^{\circ}C$, was measured In investigate the maturity of Kimchi at every 6 hours. The increasing rate was maximum at 36hours It was compatible with pH, titrable acidity and sensory evaluation test in optimum curing time. So, this method is thought as useful one for the measurement of the maturity of Kimchi.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.714-718
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• 2003

Usually for the commercial preparation of barium titanate films or ceramics the reaction atmosphere must be preferably in air. However, normally air is not used because it contains carbon dioxide, which can easily react with barium to form the undesired product barium carbonate, leading to unwanted second-phase formation in the (mal stages of the process. In the present work a series of perovskite barium titanate films was prepared by the sol-gel method, using a metal alkoxide solutions in the electrophoretic deposition (EPD). The influence of several process parameters, like sintering temperature of sol preparation before EPD and heat-treatment temperature and non-oxidized atmosphere, on the film properties is described.