• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.230-232
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• 1994

The enzymes $\alpha$-amylase and glucoamylase used in starch hydrolysis were found active in the supercritical carbon dioxide solvent Higher hydrolysis of starch sluny in supercritical $CO_2$ was achieved by operating the reactor for the first two hours with $\alpha$ -amylase and to subsequent addition of glucoamylase for continued hydrolysis.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1924-1928
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• 2004

Allylations of N-benzyl and N-methyl cyclic imides were accomplished successfully under mild Barbier type conditions using zinc metal, allyl bromide and catalytic amount of $PbBr_2$. Subsequent coupling reactions with some carbon nucleophiles afforded 1,2- and 1,4-addition products in moderate to high yields.

• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.23-25
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• 1986

Reaction of ${\alpha}-cyano-{\beta}-phenylacrylic$ acid derivatives (Ⅰ) with thioglycolic acid in the molar ratio of 1:2 in saturated sodium bicarbonate solution yielded 3-(4'-oxo-2'-thiazolin-2'-yl)-2-phenyl-4-oxotetrahydrothiophene derivatives (V). Thioglycolic acid was found to be added not only to carbon-carbon double bond but also to carbon-nitrogen triple bond and those adducts were cyclized to V.

• Journal of Powder Materials
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• v.21 no.1
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• pp.50-54
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• 2014

A powder-in-sheath rolling method was applied to a fabrication of a carbon nano tube (CNT) reinforced aluminum composite. A STS304 tube with an outer diameter of 34 mm and a wall thickness of 2 mm was used as a sheath material. A mixture of pure aluminum powders and CNTs with the volume contents of 1, 3, 5 vol was filled in the tube by tap filling and then processed to 73.5% height reduction by a rolling mill. The relative density of the CNT/Al composite fabricated by the powder-in-sheath rolling decreased slightly with increasing of CNTs content, but exhibited high value more than 98. The grain size of the aluminum matrix was largely decreased with addition of CNTs; it decreased from $24{\mu}m$ to $0.9{\mu}m$ by the addition of only 1 volCNT. The average hardness of the composites increased by approximately 3 times with the addition of CNTs, comparing to that of unreinforced pure aluminum. It is concluded that the powder-in-sheath rolling method is an effective process for fabrication of CNT reinforced Al matrix composites.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.5
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• pp.346-354
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• 2000

Effect of Nb addition on the phase transformation behavior was studied through continuous cooling transformation tests after reheating(reheating CCT) and deforming(deforming CCT) the 0.07%C-1.3%Mn-0.015%Ti-(0~0.08)% Nb steels. Transformation temperatures for deforming CCT were lower than those for reheating CCT, and the critical cooling rate for bainite transformation during deforming CCT was lower than that during reheating CCT. These enhanced hardenability for deforming CCT was considered to come from the sufficient solid solution of Nb in austenite during high temperature reheating before deformation. With Nb addition, the phase transformation temperature decreased, the bainite formation was enhanced, and the hardness of steel increased. Furthermore, these phenomena were more remarkable for deforming CCT than for reheating CCT. From the results, Nb-Ti bearing low carbon steel was considered to be a very favorable alloy system with good strength/toughness balance by recrystallization control rolling process.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.6
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• pp.725-733
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• 2014

16 water treatment plants(WTPs) in Jeju province were investigated to evaluate the corrosivity of tap water. In addition, the impacts of lime and carbon dioxide on LI changes at ES WTP were analyzed. The average of LI in Jeju tap was -1.78 which was similar to that of in-land multi-regional WTPs. The recommended process to improve LI of ES WTP which has high corrosivity(i.e., LI = -2.61) was to combine lime and carbon dioxide with the dosages of 20 mg/L and 5 mg/L respectively to meet LI of -1.0 ~ 0. pH was confirmed to be a major water quality parameter that determined LI based on the correlation results among LI and water quality parameters. Precaution on turbidity increase by lime addition should given to minimize particle breakthrough in the distribution system. Turbidity increase can be controlled by the addition of lime prior to filters.

• The Korean Journal of Ceramics
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• v.3 no.4
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• pp.229-234
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• 1997

Silicon carbide-carbon fiber composites have been prepared by partially Infiltrating porous carbon fiber composites with liquid silicon at a reaction temperature of $1670^{\circ}C$. Reaction between molten silicon and the fiber preform yielded silicon carbide-carbon fiber composites composed of aggregates of loosely bonded SiC crystallites of about 10$\mu\textrm{m}$ in size and preserved the appearance of a fiber. In addition, the SiC/C fiber composites had carbon fibers coated with a dense layer consisted of SiC particles of sizes smaller than 1$\mu\textrm{m}$. The physical and mechanical properties of SiC/C fiber composites were discussed in terms of infiltrated pore volume fraction of carbon preform occupied by liquid silicon at the beginning of reaction. Lower bending strength of the SiC/C fiber composites which had a heterogeneous structure in nature, was attributed to the disruption of geometric configuration of the original carbon fiber preform and the formation of the fibrous aggregates of the loosely bonded coarse SiC particles produced by solution-precipitation mechanism.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.131-141
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• 2009

The conversion of carbon dioxide to value-added compounds has been attracted to solve the environmental problems due to the climate change caused by greenhouse effect in addition to recycle the abundant and renewable carbon source. For utilizing carbon dioxide to useful compounds, the development of catalysts and optimization of experimental conditions are indispensable since carbon dioxide is the most stable one among carbon compounds and the a certain amount of energy is required for the carbon dioxide conversion. The technologies developed for the electrochemical carbon dioxide conversion were reviewed in terms of electrocatalyst which can be electrode material, inorganic complex, and enzyme. This field should be developed further since no good catalyst having selectivity, efficiency, and stability all together.

• Journal of Environmental Impact Assessment
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• v.19 no.6
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• pp.625-631
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• 2010

The objective of this work was to investigate how carbon sink and sequestration of vegetation and soil in the development project area can impact the land use plan, in addition to carbon emission capacity of the development project when we conduct environmental impact assessment. Especially, we did this work for a development project of solar power plant which would be constructed in forest area. Through this work, we found that 1) the amount of carbon sink and sequestration largely decreased due to reduction of the green area, 2) in terms of carbon sink and sequestration, conservation of natural green area is better than construction of newly vegetated area, 3) biochar application into soil can become an alternative for increase of carbon sink, and 4) even though a solar power production does hugely reduce carbon emissions and offset the carbon sink and sequestration capacity from the forest, it is necessary to consider the public value of the forest(reduction of heat island, habitat etc.) in siting for development area.

• Design & Manufacturing
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• v.17 no.2
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• pp.27-32
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• 2023

Liquid silicon rubber (LSR) has fine thermal compatibility and is widely used in various fields such as medical care and automobiles because it is easy to implement products with good fluidity. With the recent development of flexible sensors, the focus has been on manufacturing conductive elastomers, such as silicone as elastic materials, and carbon black, CNT, and graphene are mainly used as nanomaterials that impart conductive phases. In this study, mechanical behavior and curing behavior were measured and analyzed to manufacture a CB-LSR complex by adding Carbon Black to LSR and to identify properties. As a result of the compression test, the elastic modulus tended to increase as carbon black was added. When the swelling test and the compression set test were conducted, the swelling rate tended to decrease as the content of carbon black increased, and the compression set tended to increase. In addition, DSC measurements showed that the total amount of reaction heat increased slightly as the carbon black content increased. It is considered that carbon black was involved in the crosslinking of LSR to increase the crosslinking density and have a positive effect on oil resistance reinforcement.