• Journal of Hydrogen and New Energy
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• v.19 no.5
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• pp.439-444
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• 2008

The heat capacity and pressure drop of $CO_2$ and coolant in a multi-tube type gas cooler were investigated experimentally. The main components of the refrigerant loop are a receiver, a $CO_2$ compressor, a mass flow meter, an evaporator and a multi-tube type gas cooler as a test section. The mass flowrate of $CO_2$ and coolant were varied from 0.06 to 0.075 [kg/s], respectively and the cooling pressure of gas cooler were from 8 to 10 [MPa]. The heat capacity of $CO_2$ in the test section is increased with the increment in mass flowrate of coolant, the cooling pressure and mass flowrate of $CO_2$. The pressure drop of $CO_2$ is decreased with the decrease in mass flowrate of coolant and $CO_2$, but decreased with increase in cooling pressure of $CO_2$. The heat capacity of $CO_2$ per unit heat transfer area of gas cooler is greatly high. Therefore, in case of the application of $CO_2$ at the multi-tube type gas cooler, it is expected to carry out the high-efficiency, high-performance and compactness of gas cooler.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.8
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• pp.694-701
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• 2007

The applications of a transcritical $CO_2$ cycle into water heaters show advantages over conventional systems in the respect of power consumption and heating efficiency because the $CO_2$ cycle has a high compressor discharge temperature. Besides, the heating performance of the transcritical $CO_2$ cycle can be improved by optimizing operating conditions. In this study, the heating performance of a variable speed $CO_2$ heat pump was measured and analyzed by varying refrigerant charge amount, EEV opening, compressor frequency and outdoor temperature. As a result, the optimum normalized charge for heating was 0.226. The COPs at the compressor frequencies of 40, 50 and 60 Hz were 2.94, 2.75 and 2.25, respectively. The heating performance of the $CO_2$ cycle with charge amount was more sensitive than the cooling performance. Moreover, the heating performance was improved significantly by optimizing of compressor frequency and EEV opening.

• Biomedical Science Letters
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• v.12 no.3
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• pp.161-170
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• 2006

A new piperazine derivative, 8J-8029, is a synthetic anti-cancer agent which exhibits both microtubule and topoisomerase II inhibiting activities. In this study, we investigated the ability of 8J-8029 for anti-angiogenesis and apoptosis. 8J-8029 decreased the bFGF-induced angiogenesis in the CAM and the mouse Matrigel implants, in vivo. 8J-8029 inhibited the proliferation, migration, invasion, tube fonnation, and expression of MMP-2 in BAECs. In addition, 8J-8029 reduced the cell viability in HepG2 cells, caused the production of fragmented DNA and the morphological changes corresponding to apoptosis. 8J-8029 also elicited the release of cytochrome c and the activation of caspase-3. Taken together, these results suggest 8J-8029 may be a candidate for anti-cancer agent with the ability to inhibit the angiogenesis of endothelial cells and to induce the apoptosis of tumor cells.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.193-206
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• 2018

In this study, as part of the "Small-scale $CO_2$ Injection-Demonstration Project in Offshore Pohang Basin", we performed drilling and completion of a $CO_2$ injection well from the offshore platform installed in the Yeongil Bay, Pohang city, Gyeongsang buk-do. The drilling of injection well was carried out from an offshore platform installing on the sediment formations of the Pohang Basin. Drilling diameters were reduced by stages, depending on the formation pressure and groundwater pressure along a depth and the casing installation and cement grouting in drilled hole were performed at each stage. The injection well was drilled to a final depth of 816.5 m with a hole diameter of 4 7/8 inches (${\Phi}124mm$) and the perforated casing for an injection section was installed in a depth of 746.5~816.5 m. Injection tubing, packer, and christmas tree were installed for the completion of an injection well for $CO_2$. The validation project of the $CO_2$ injection was accomplished successfully by drilling the injection well and installing the injection facilities, and through the suitable $CO_2$ injection process. The current injection facility is a facility for small-scale injection demonstration of 100 tons. In the case of large-scale demonstration facility test of a capacity of 10,000 tons, research is underway through the upgrading of the injection facilities.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.87-92
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• 2001

Magnetic Fe-Co(C) nanocapsules and Fe-Co nanoparticles were prepared by arc-discharge in two kinds of atmospheres, i.e. methane and a mixture of ($H_2$+Ar), respectively. Characterization and magnetic properties of this two kinds of ultrafine particles were investigated systematically by means of X-ray diffraction, Mssbauer spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy disperse spectroscopy analysis, chemical analysis, oxygen determination and magnetization measurement. Effects of carbon element, decomposed from a methane atmosphere in carbon arc process, on phase structures, magnetic states and surface characterization were studied in comparison to that of Ar element. Two ultrafine particles showed a little difference in the weight ratio of (Fe/co) and the size for Fe-Co nanoparticles was about two times bigger than Fe-Co(C) nanocapsules. The saturation magnetization of Fe-Co (C) nanocapsules was about 8% higher than that of Fe-Co nanoparticles while their phase constitutions were similar. Although no carbon could be detected by XRD measurement because of extremely thin shells on the surfaces of the cores, it is still believed that they are carbon and oxygen layers.

• Journal of the Korean Ceramic Society
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• v.19 no.4
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• pp.309-315
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• 1982

$FeAl_2O_4$ was formed from the starting material of $Fe_2O_3$ and $Al_2O_3$ by controlling the oxygen partial pressure using $H_2-CO_2$ gas mixture, over the temperature range of 800~120$0^{\circ}C$. The formation mechanism of $FeAl_2O_4$ was found to be a second order chemical reaction, and the activation energy of formation was observed as 39.97 kcal/mole. Vaporization behavior of $FeAl_2O_4$ under $CO_2$ atmosphere was observed over the temperature range of 800~120$0^{\circ}C$. $FeAl_2O_4$ was vaporized by a second order chemical reaction and the activation energy was found to be 21.8kcal/mole. Electrical conductivity of $FeAl_2O_4$ was also measured.

• The Korean Journal of Pesticide Science
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• v.7 no.2
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• pp.108-116
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• 2003

A series of new quinclorac family, herbicidal 3-phenyl-5-(3,7-dichloro-8-quinolinyl)-1,2,4-oxadiazole derivatives as substrate were synthesized and their growth inhibition activity $(pI_{50})$ against root and shoot of rice plant (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli) were determined. And then comparative molecular field analysis (CoMFA) and molecular holographic quantitative structure- activity relationship (HQSAR) were compared in terms of their potential for predictiability. The statistical results were suggested that HQSAR based model had better predictability than CoMFA model. The selective factors to remove barnyard grass take electron withdrawing groups which can be created positive charge and steric bulky on the phenyl ring. Results revealed that the unknown 2,6-dichloro-substituent, U5 and 2,4,6-trichloro-substituent, U6(${\Delta}pI_{50}$=CoMFA: 1.18 & HQSAR: 1.82) were predicted as compound with higher activity and selectivity.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.115-120
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• 2015

$K_2CO_3$-based dry regenerable sorbents were prepared by spray-drying techniques to improve mass produced $K_2CO_3-Al_2O_3$ sorbents (KEP-CO2P, hereafter), and then tested for their $CO_2$ sorption capacity by a $2,000Nm^3/h$ (0.5 MWe) $CO_2$ capture pilot plant built for Unit 3 of the Hadong thermal power station in 2010. Each of the sample sorbents contained 35 wt.% $K_2CO_3$ as the active materials with various support materials such as $TiO_2$, MgO, Zeolite 13X, $Al_2O_3$, $SiO_2$ and hydrotalcite (HTC). Their physical properties and reactivity were tested to evaluate their applicability to a fluidized-bed or fast transport-bed $CO_2$ capture process. The $CO_2$ sorption capacity and percentage utilization of $K_2CO_3$-MgO based sorbent, Sorb-KM2, was $8.6g-CO_2/100g$-sorbents and 90%, respectively, along with good mechanical strength for fluidized-bed application. Sorbs-KM2 and KT were almost completely regenerated at $140^{\circ}C$. No degradation of Sorb-KM by $SO_2$ added as a pollutant in flue gas was observed during a cycle test.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.483-492
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• 2014

DNA damage such as genotoxicity was identified with comet assay, which blood cell of a marine parrot fish (Oplegnathus fasciatus) was exposed to an acidified seawater, lowered pH gradient making of $CO_2$ gas. The gradient of pH were 8.22, 8.03, 7.81, 7.55 with control as HBSS solution with pH 7.4. DNA tail moment of fish blood cell was $0.548{\pm}0.071$ exposed seawater of pH 8.22 condition, on the other hand, DNA tail moment $1.601{\pm}0.197$ exposed acidified seawater of pH 7.55 lowest condition. The approximate difference with level of DNA damage was 2.9 times between highest and lowest of pH. DNA damage with decreasing pH was significantly increased with DNA tail moment on blood cell of marine fish (ANOVA, p < 0.001). Ocean acidification, especially inducing the leakage of sequestered $CO_2$ in geological structure is a consequence from the burning of fossil fuels, and long term effects on marine habitats and organisms are not fully investigated. The physiological effects on adult fish species are even less known. This result shown that the potential of dissolved $CO_2$ in seawater was revealed to induce the toxic effect on genotoxicity such as DNA breakage.

• Journal of the Korean Chemical Society
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• v.35 no.1
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• pp.90-95
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• 1991

A method for the selective syntheses of alkyl (alkoxymethyl)benzoates from halobenzyl halides by two steps in one pot process is described. In the first step, benzyl halide moiety is etherified with alkoxide anion in alcohol by Williamson ether process. In the second step, aryl halide moiety is carbonylated to give alkyl (alkoxymethyl)benzoate with alcohol, Na$_2$CO$_3$, CH$_3$I, and carbon monoxide (1 atm) in the presence of a catalytic amount of Co$_2$(CO)$_8$ in excellent yield.