• Clean Technology
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• v.27 no.4
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• pp.325-331
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• 2021

In this study, bio-carbons were produced by activation process from unused biomass (Grade 3 wood pellet and spent coffee grounds) to determine the removal performance of formaldehyde and acetaldehyde. The activation experiments were conducted in a fixed bed reactor using CO₂ as an activation agent. The temperature of the activation reactor and input of CO₂ were 900 ℃ and 1 L min^-1 for all the experiments. The maximum BET surface area of about 788 m² g^-1 was obtained for bio-carbon produced from Grade 1 wood pellet, whereas about 544 m² g^-1 was achieved with bio-carbon produced from spent coffee grounds. In all the experiments, the bio-carbons produced were mainly found to have micro-porous nature. A lower ash amount in raw material was favored for the high surface area of bio-carbons. In the removal test of formaldehyde and acetaldehyde, the bio-carbon produced from spent coffee grounds showed excellent adsorption performance compared with woody biomass (Grade 1 wood pellet and Grade 3 wood pellet). In addition, the comparative experiment of commercial impregnated activated carbon and bio-carbon produced from spent coffee grounds was conducted. In terms of formaldehyde removal performance, the commercial impregnated bio-carbon was excellent, while bio-carbon produced from spent coffee grounds was excellent in acetaldehyde removal.

• Journal of Environmental Impact Assessment
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• v.22 no.1
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• pp.1-17
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• 2013

Carbon sequestration on soil is one of the counter measurements against climate change in agricultural sector. Increasing incorporation of organic fertilizer would increase soil organic carbon (SOC) but it could bring high potential of nutrient losses which would result in water quality degradation. In this paper, literature review on soil organic carbon behavior according to agricultural management is presented. The results of field experiment to identify the effect of organic and commercial fertilizer applications on SOC and runoff water quality were also presented. Field experiment confirmed increased SOC and nutrient concentrations in runoff water as application rate of organic fertilizer increase. The potential use of simulation model to develop best agricultural management practice considering carbon sequestration and water quality conservation at the same time is discussed and monitoring and modeling strategies are also suggested to achieve the goal.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.179-186
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• 2006

Single-walled carbon nanotubes (SWNT) exhibit strong Raman signals as well as fluorescence emissions in the near infrared regions where most biomolecules are transparent. Such signals do not blink or photobleach under prolonged excitation. which is advantageous to optical nano-bio marker applications. In this paper, single walled carbon nanotubes are conjugated with specific types of single-stranded DNA in order to detect oligonucleotides of corresponding complimentary sequences. Dot blotting experiments and comparative Raman spectroscopy observations demonstrated excellent sensitivity and specificity of carbon nanotube-DNA probes. The results show the possibility of using SWNT as generic nano-bio markers for the precise detection of specific kinds of genes.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.265-269
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• 2007

The effects of experimental variables for the electrochemical reduction of carbon dioxide by Carbon Monoxide Dehydrogenase (CODH) were investigated. It shows the pH optimum at 6.3 where the feasibility of electro-chemical reduction and the stability of CODH compromise each other. The optimum temperature for the reduction was at $60^{\circ}C$ where the enzyme shows the optimum activity although the solubility of carbon dioxide decreases as increasing temperature.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.478-481
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• 2005

In this study optical sensing membrane was developed for the queantification of dissolved carbon dioxide in micro-bioreactor using an immobilized 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS). For the immobilization of HPTS sol-gel was synthesied by using 3-glycidoxypropyl-dimethoxymethylsiline and tetraethyl orthosilicate.

• Carbon letters
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• v.16 no.3
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• pp.211-214
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• 2015

Bio-imaging and drug carriers for delivery have created a huge demand for crystals. Crystals are fascinating materials that have been grown for a long time but obtaining biocompatible fluorescent crystals is a challenging task. We report on the growth of fluorescent crystals using a carbon dot (C-dot) solution by a hydrothermal process. The crystallization pattern of these C-dots exhibited a unique dendritic structure having a feather-like morphology. The growth temperature and pressure were maintained at 60℃ and 200 mmHg, respectively, for crystal growth. A green fluorescence (under UV light) that was observed in the C-dot solution was retained in the crystals formed from the solution. Cytotoxicity studies on Vero cells revealed the crystals to be extremely biocompatible. These fluorescent crystals are extremely well suited for biomedical and optoelectronic applications.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.3
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• pp.247-257
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• 2003

To investigate the effect of preparing condition on the physical properties of carbon nanotubes suitable for optical applications, carbon nanotubes were synthesized by thermal chemical vapor deposition using Ni particles as a catalyst on stainless steel substrate and acetylene as a reactant gas. To examine the physical and optical properties, SEM, TEM, Ram an, UV-visible, and photoluminescence spectroscopy were used. The physical properties of carbon nanotubes such as diameter, degree of growth density and morphology were closely related to such experimental conditions as Ni particle size, growing pressure, and etching condit on of Ni particles, it appeared from the light absorbance and photoluminescence spectra of carbon nanotube mixture prepared with an addition of a photopolymer, P3HT(Poly(3-hexylthIop hene)) that carbon nanotube could do a role as a kind of electron acceptor for solar cell application.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.131-137
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• 2012

This article is about using the fuel mixed with 10% and 20% bio-ethanol to gasoline for the engine as a way to reduce carbon emission before commercializing future automobiles like fuel cell cars. The fuel mixed with 10% and 20% bio-ethanol showed output equivalent to that of the previous gasoline fuel. CO and $CO_2$ emission was somewhat reduced, but the difference was not significant. And the consumption of the fuel increased slightly. However, bio-ethanol is produced from bio mass growing with the absorption of carbon dioxide, so the total amount of carbon dioxide did not increase according to the result. In NOx, as the use of ethanol increases, the effect of reduction gets greater, and the emission of oxygen showed almost no change compared with gasoline.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.2
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• pp.114-121
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• 2009

There are increased in using the bio-ethanol, as the carbon neutral attracts many researchers due to a reduction in carbon dioxide spotted as the global warming gas. A gasoline engine with 100% of the bioethanol was developed and used in Brazil already, but researches of using the bio-ethanol in diesel engines are lack. In this study, combustion tests with blend fuel of the gas oil and bio ethanol by 50% maximally due to a low cetane number of bio-ethanol were accomplished as a basic study of introduction of using the bioethanol in diesel engines. The result was that smoke emission was decreased with increase in proportion of the bio-ethanol, due to the increase of a amount of pre-mixed combustion with ignition delay. Although the amount of $CO_2$ is reduced according as the bio-ethanol is used(carbon neutral), the emission of $CO_2$ with increase in the proportion of the bio-ethanol was more increased due to lower a heat value of bio-ethanol than gas oil.

• Journal of the Korean Electrochemical Society
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• v.11 no.3
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• pp.165-169
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• 2008

The effect of reduction of carbon dioxide by CODH(Carbon Monoxide Dehydrogenase) was compared on glassy carbon and gold working electrodes. In case of gold electrode, the choice of the optimum applied potential is very important since $H_2$ evolution can be mixed with $CO_2$ reduction. On the other hand, efficient $CO_2$ reduction was observed up to -650 mV vs. NHE on glassy carbon in neutral solution due to the larger overpotential for $H_2$ evolution on glassy carbon surface than that on gold surface. The optimum potential for $CO_2$ reduction was found to be $-570{\sim}600\;mV$ vs. NHE. The current efficiency of $CO_2$ to CO decreased dramatically at more negative potential according to the activity of enzyme decrease and the hydrogen evolution.