• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.1
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• pp.9-15
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• 2004

$CO_2$ is a well-known green house gas as well as the major source of global warming. Many researchers have studied to reduce $CO_2$ emission in combustion processes. Among the method for reducing $CO_2$ emission, oxygen-enriched combustion has been proposed. Because its adiabatic flame temperature is relatively too high, existing facilities must be changed or the flame temperature in the combustion zone should be reduced. The combustion characteristics, composition in the flame zone, temperature profile and emission gases were investigated experimentally for the various oxygen-enriched ratios(OER) by the addition of $CO_2$, under constant $O_2$ flow rate. Results showed that the reaction zone was quenched and broadened as the addition of $CO_2$ was increased. The emission of NOx in flue gas was decreased as decreasing temperature in reaction zone. It was also shown that the reaction was delayed by the cooling effect. As the addition of $CO_2$ was increased, the composition of CO in the flame zone was increased due to the increase of reaction rate by increasing mixing effect of oxidant/fuel at OER=0％, but the composition of CO was decreased by quenching effect at OER=50％ and 100％.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.456-460
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• 2012

Au/$SnO_2$ core-shell structure nanoparticles (NPs) were synthesized by microwave hydrothermal method, and the effect of working temperature on sensitivity of Au/$SnO_2$ core-shell NPs for CO gas was investigated. The $SnO_2$ shell layer was consisted of $SnO_2$ primary particles with 4.5 nm diameter. The response of Au/$SnO_2$ core-shell NPs for CO gas was maximized at the working temperature of $350^{\circ}C$ while the sensitivity increased with decreasing the working temperature due to the low grain size effect of $SnO_2$ NPs on the response of CO gas.

• Journal of Korea Foundry Society
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• v.14 no.6
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• pp.499-507
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• 1994

The effect of sodium gluconic acid on the collapsability of the sodium silicate type $CO_2$ mold was studied. The bending strength was saturated with gassing $CO_2$ for 60 sec. under $1kg/cm^2$ and with the flow rate of $10\;{\ell}\;/min$. It was decreased with aging after having been fully hardened. The retained strength was reduced in the heating temperature range of $100{\sim}1,100^{\circ}C$ and the retained strength peak near the heating temperature of $100^{\circ}C$ was removed by the effect of the sodium gluconic acid. Silica gel, $Na_2CO_3$ and dehydrated sodium silicates were formed from the binder of sodium silicate with the addition of sodium gluconic acid at the heating temperature of $100^{\circ}C$. $Na_4SiO_4$ was formed by the reaction of $Na_2O$, from decomposed $Na_2CO_3$, with the dehydrated sodium silicate at $500^{\circ}C$. The crystobalite type of $SiO_2$ was formed at $900^{\circ}C$. The sodium gluconic acid had no effect on the bending strength at around $1,100^{\circ}C$ due to the combustion loss of it.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.355-359
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• 1988

The Pfeiffer effect was examined on the systems of racemic [$Co^{II}(acac)_2$(diamine)] with d-cinchonine and l-cinchonidine as chiral environment substances in methanol, ethanol, chloroform and methanol-chloroform mixture solvents. It was found that the ${\Delta}$-enantiomer is enriched for the [$Co^{II}(acac)_2$(diamine)]-d-cinchonine system, but the Λ -enantiomer is enriched for the [$Co^{II}(acac)_2$(diamine)]-l-cinchonidine system. The complexes having no N-H protons such as [$Co^{II}(acac)_2$(bpy)] and [$Co^{II}(acac)_2$(phen)] were Pfeiffer-inactive in alcoholic solvents, where bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline. This was interpreted to mean that the hydrogen bonding between N-H proton of diamine ligand and C-9 hydroxyl group of alkalid plays an important role in the chiral discrimination. And the rate of antiracemization ($k_{anti}$) by the Pfeiffer effect was also measured for the [$Co^{II}(acac)_2$(diamine)]-d-cinchonine system in alcoholic solvents. It was found that the rate of appearance of the Pfeiffer effect was enhanced as the concentration of added chloroform is increased.

• KIEAE Journal
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• v.14 no.2
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• pp.87-98
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• 2014

This study is to identify quantitatively the function of carbon dioxide emissions reduction due to temperature and energy reduction according to direct carbon dioxide storage, shade provision, and evaportanspiration of urban park. According to the result of study, landscape tree indicated high carbon dioxide storage effect compare to bush, in which broadleaf tree indicated higher storage function than coniferous tree. It is believed to be the storage of carbon dioxide can be increased by increasing the composition rate of forest plants in the urban park. According to the direct estimation result of carbon dioxide storage in terms of example area, storage of carbon dioxide is estimated to be "seoul a zone" $476,818.8kg{\cdot}CO_2/m^2yr$, "anyang b zone" $186,435.7{\cdot}CO_2/m^2yr$, "daejeon c zone" $262,826{\cdot}CO_2/m^2yr$, "kwangju d zone" $231,657.8{\cdot}CO_2/m^2yr$. The carbon dioxide storage per unit area estimated to be "seoul a zone" $3.4{\cdot}CO_2/m^2yr$, "anyang b zone" $5.0{\cdot}CO_2/m^2yr$, "daejeon c zone" $2.6{\cdot}CO_2/m^2yr$, "kwangju d zone" $5.6{\cdot}CO_2/m^2yr$. The result of indirect carbon dioxide reduction effect estimated to be "seoul a zone" $291,603.4{\cdot}CO_2/m^2yr$, "anyang b zone" $165,462.4{\cdot}CO_2/m^2yr$, "daejeon c zone" $141,719.2{\cdot}CO_2/m^2yr$, "kwangju d zone" $154,803.4{\cdot}CO_2/m^2yr$. Carbon dioxide reduction potential amount through the urban park was increased to 1.6 times to 1.8 times when calculated to the indirect effect.

• Advances in environmental research
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• v.4 no.1
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• pp.17-24
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• 2015

In this study, we numerically investigated the effect of pressure (100-250 bar), temperature (274-288 K), and salinity (3.5% w/w electrolytes) on $CO_2$ hydrate dissolution rates in the ocean. Mass transfer equations and $CO_2$ solubility data were used to estimate the $CO_2$ hydrate dissolution rates. The higher pressure and lower temperature significantly reduced the $CO_2$ hydrate dissolution rates due to the increase of $CO_2$ particle density. In the high salinity condition, the rates of $CO_2$ hydrate dissolution were decreased compared to pure water control. This is due to decrease of $CO_2$ solubility in surrounding water, thus reducing the mass transfer of $CO_2$ from the hydrate particle to $CO_2$ under-saturated water. The results obtained from this study could provide fundamental knowledge to slow down or prevent the $CO_2$ hydrate dissolution for long-term stable $CO_2$ storage in the ocean as a form of $CO_2$ hydrate.

• Environmental and Resource Economics Review
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• v.28 no.1
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• pp.1-37
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• 2019

This study investigates the convergence in per capita $CO_2$ emission by income group for an unbalanced panel of 152 countries from 1980 to 2013 using beta and sigma convergence model. Absolute beta and sigma convergence differed by $CO_2$ emission reduction policies in each countries. Conditional beta convergence shows that per capita income has a negative effect on growth in per capita $CO_2$ emission. In particular, better-quality institutions and technology accelerated the negative effect of per capita income on the speed of convergence of per capita $CO_2$ emission in high-income countries. For middle-income countries, the growth of income affected the convergence of $CO_2$ emission per capita, but institutional quality has an insignificant impact. On the other hand, improvements in the level of technology have a mitigating effect on the negative impact of income in middle-income and low-income countries, contributing to the increase in $CO_2$ emission.

• Proceedings of the Korean Magnestics Society Conference
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• 2001.10a
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• pp.44-45
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• 2001

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.2
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• pp.115-121
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• 2014

Since the rapid development of information age and information technology might be considered to cause environmental problems, Green IT is perceived as core technology for low carbon green growth and the minimum waste of electricity. In this vein, Green IT is becoming new paradigm of focusing on natural environment. This study examines current various IT required for green growth, and studies various methods for diminution of carbon discharge in Korea and other countries. Especially, it focuses on the diminution effect of carbon discharge by using Green PC, and compares the difference of voltage, voltaic current, and the use of electricity between Normal PC and Green PC by using HPM-300A, and measures carbon discharge of Normal PC and Green PC. The result shows that the diminution effect of $CO_2$ discharge of Green PC is amount to 11.5Kg per year, and the effect of green growth is up to the conservation of 2 or 3 pine trees.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.1
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• pp.23-29
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• 1997

Effects of Co thickness on the formation of epitaxial $CoSi_2$ from the Co/Ti bilayer have been investigated. Ti and Co were sequentially deposited with the Ti thickness fixed at 5 or 10nm, while the Co thickness was varied from 5 to 30nm. The metal-deposited samples were then rapidly thermal-annealed in $N_2$ at $900^{\circ}C$ for 20 sec. Material properties of $CoSi_2$ thin films were analyzed by the 4-point probe, XRD, AES, andXTEM. When the as-deposited Co thickness was below 15nm, the $CoSi_2$ with high resistivity and rough interface was formed. On the other hand, when the Co thickness was above 15 nm, the epitaxial $CoSi_2$ with the resistivity of about 16 ~ 19 $\mu\Omega.cm$, uniform composition and thickness and flat interface was formed. Initial Ti thickness has sizable effect on the formation of $CoSi_2$, when the Co layer was very thin (~ 5 nm). But there was no significant effect of the Ti thickness for the initial Co thickness of above 15 nm.