• Journal of Korean Society of Archives and Records Management
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• v.1 no.1
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• pp.231-243
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• 2001

The sterilization method of records by fumigation using mixed gas of methyl bromide(MB) and ethylene oxide(ETO) has been generally used as a way to protect biological deterioration by microorganisms and insects. In this study, we confirmed sterilization effect of MB and ETO [86 : 14(Vol.%)] on and analyzed toxicity on microorganisms isolated from records. To analyze sterilization effect of fumigation on microorganisms and insect, we have fumigated microorganisms and insect with a various amounts mixed gas of MB and ETO, and various exposure time. Insect was sterilized at all experimental conditions. In microorganisms, sterilization effect was detected only when the mixed gas was treated at $120g/m^3$ concentration for at least 24 hrs. To test the possibility of isolated microorganisms as a threat to human health, it was investigated that toxicity test using yeast, radish and cancer cells on microorganisms. Only Aspergillus oryzae had an inhibition effect on growth of yeast. radish and cancer cells, respectively. These results demonstrate that sterilization effect can occur at low concentrations of the mixed gas on insect but requires higher concentrations of the mixed gas on microorganisms. In addition to, it is suspected that the possibility of the microorganism as a threat to human health is little.

• Journal of Conservation Science
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• v.25 no.3
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• pp.283-291
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• 2009

Methyl Bromide that was used as fumigation gas turned out to be the substance of destroying the ozone layer. For that reason, at the Montreal Protocol in 1987 the use of methyl bromide was forbidden starting 2005 in the advanced country. Also according to the 2007 Bali Protocolly methyl bromide is expected to be forbidden and therefore the purpose of this study is to find out the effects of substitution fumigation gas (Ethylene Oxide+HFC 134a, Methyl Iodide, Cyanogen and Argon) on the metal(silver, copper and iron), wood(oregon pine), pigment(yellow, red, blue, white and black), textile(hemp, ramie, jute, silk1 and silk2 / indigo, safflower and cork) and paper. After the fumigation test, ethylene oxide+HFC 134a did not have changes in the weight and color of the material itself before and after the experiment. On exterior alteration, color change occurred partly on paper and metal. Also, in most materials color change extent was 0.5 to 1.5 on the average and showed scanty difference. The materials after the fumigation test with methyl iodide did not show weight changes after the test. However, color changes more than 1.0 was shown in most of the materials especially in dyed textile material. In blue pigment, the discoloration on the surface could be seen by naked eyes. Fumigation test with cyanogen gas did not show weight changes and discoloration is more than 1.5 before and after the test. The weight changes of test materials with the argon gas was decreased about 3 to 6%. It can be observed that discoloration on paper was generated. Color changes can be seen on jute dyed with safflower and cork for two weeks with argon gas and the extent was 6.3 and 6.0.

• 한국가스학회:학술대회논문집
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• no.5
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• pp.183-188
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• 2002

• ETRI Journal
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• v.34 no.5
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• pp.713-718
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• 2012

Sensor nodes in ubiquitous sensor networks require autonomous replacement of deteriorated gas sensors with reserved sensors, which has led us to develop an encapsulation technique to avoid poisoning the reserved sensors and an autonomous activation technique to replace a deteriorated sensor with a reserved sensor. Encapsulations of $In_2O_3$ nanoparticles with poly(ethylene-co-vinyl alcohol) (EVOH) or polyvinylidene difluoride (PVDF) as gas barrier layers are reported. The EVOH or PVDF films are used for an encapsulation of $In_2O_3$ as a sensing material and are effective in blocking $In_2O_3$ from contacting formaldehyde (HCHO) gas. The activation process of $In_2O_3$ by removing the EVOH through heating is effective. However, the thermal decomposition of the PVDF affects the property of the $In_2O_3$ in terms of the gas reactivity. The response of the sensor to HCHO gas after removing the EVOH is 26%, which is not significantly different with the response of 28% in a reference sample that was not treated at all. We believe that the selection of gas barrier materials for the encapsulation and activation of $In_2O_3$ should be considered because of the ill effect the byproduct of thermal decomposition has on the sensing materials and other thermal properties of the barrier materials.

• Membrane Journal
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• v.25 no.6
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• pp.547-557
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• 2015

In this study, we synthesized polyimide with high carbon dioxide gas transport property using 2,2-bis(3,4-carboxylphenyl) hexafluoropropane, 2,3,5,6-tetramethyl-1,4-phenylenediamine and poly(ethylene glycol) bis(3-aminopropyl) terminated and then we calculated solubility parameter of synthesized polymer and non-solvent phase separation coefficient to determine proper solvent for preparation of asymmetric membrane, also we measured the viscosity of the polymer solution to check polymer contents in membrane solution and prepare asymmetric membrane with $LiNO_3$ additives. The morphology and gas separation property of membrane prepared by phase separation method was confirmed using Field Emission Scanning Electron Microsope and the single gas permeation measurement apparatus. We confirmed that the carbon dioxide permeance of the membrane increased and the selectivity showed little change with decreasing of the volatile solvent contents.

• KSBB Journal
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• v.9 no.2
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• pp.180-185
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• 1994

The productivity of alkaloid in the airlift fermentor operation was less than that of suspension coltures of Eschscholtzia californica cells in the shake flask. To overcome the productivity reduction, a gas recycle airlift fermentor was developed because the gas-stripping in normal airlift fermentor was believed to play a significant role for productivity reduction. The alkaloid content in the gas recycle system with Eschscholtzia californica suspension cells was 2.7 times higher than that of normal airlift fermentor. The productivity of alkaloids and $CO_2$ concentration were affected by the volume of gas reservoir in the gas recycle airlift fermentor.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.230-236
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• 2017

Solubility data of carbon dioxide ($CO_2$) in poly(ethylene glycol) dimethyl ether (PEGDME) are presented at pressures up to about 50 bar and at temperatures between 303 K and 343 K. The solubilities of $CO_2$ were determined by measuring the bubble point pressures of the $CO_2+PEGDME$ mixtures with various compositions using a high-pressure equilibrium apparatus equipped with a variable-volume view cell. To observe the effect of the PEGDME molecular weight on the $CO_2$ solubility, the $CO_2$ solubilities in PEGDME with two kinds of molecular weight were compared. As the equilibrium pressure increased, the $CO_2$ solubility in PEGDME increased. On the other hand, the $CO_2$ solubility decreased with increasing temperature. When compared at the same temperature and pressure, the PEGDME with a higher molecular weight gave smaller $CO_2$ solubility on a mass fraction and molality basis, but gave greater $CO_2$ solubilities on a mole fraction basis.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.143-148
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• 2010

In this study, the potential possibility of biodiesel fuel(BDF) and oxygenated fuel(ethylene glycolvmono-n-butyl ether; EGBE) was investigated as an effective method of decreasing the smoke emission. The smoke emission of blending fuel (BDF and EGBE 0~20 vol-%) was reduced in comparison with diesel fuel and it was reduced approximately 64% at 2000 rpm, full load in the 20% of blending rate. But torque and brake specific energy consumption( BSEC) didn't have no large differences. Also, the effects of exhaust gas recirculation(EGR) for the reduction of NOx emission has been investigated. Consequently, It was found that simultaneous reduction of smoke and NOx emission was achieved with BDF(90 vol-%) and EGBE(10 vol-%) blended fuel and cooled EGR method(5~10%).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1081-1092
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• 2004

The synthesis of Ni-catalyzed multi-walled carbon nanotubes and nanofibers on a catalytic metal substrate, using an ethylene fueled inverse diffusion flame as a heat source, was investigated. When the gas temperature was varied from 1,400K to 900K, approximately, carbon nanotubes with diameters of 20∼60nm were formed on the substrate. In the regions where the gas temperature was higher than 1,400K or lower than 900K, iron nanorods or carbon nanofibers were synthesized, respectively. Based on the quantitative analyses of large amount of SEM and TEM images, the nanotubes formed closer to the flame had a tendency of having larger diameters. HR-TEM images and Raman spectra revealed that carbon nanotubes synthesized had multi-walled structures with some defective graphite layers at the wall. Based on the graphite mode of the Raman spectra, it was believed that the optimal synthesis could be obtained as the substrate was positioned at between 5.5mm and 5.0mm, from the flame axis.

• Journal of Powder Materials
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• v.17 no.4
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• pp.276-280
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• 2010

In the present work, ethylene glycol-based (EG) copper oxide nanofluids were synthesized by pulsed wire evaporation method. In order to explode the pure copper wire, high voltage of 23 kV was applied to the both ends of wire and argon/oxygen gas mixture was used as reactant gas. EG-based copper oxide nanofluids with different volume fraction were prepared by controlling explosion number of copper wire. From the transmission electron microscope (TEM) image, it was found that the copper oxide nanoparticles exhibited an average diameter about 100 nm with the oxide layer of 2~3 nm. The synthesized copper oxide consists of CuO/$Cu_2O$ phases and the Brunauer Emmett Teller (BET) surface area was estimated to be $6.86\;m^2\;g^{-1}$. From the analyses of thermal properties, it is suggested that viscosity and thermal conductivity of EG-based copper oxide nanofluids do not show temperature-dependent behavior over the range of 20 to $90^{\circ}C$. On the other hand, the viscosity and thermal conductivity of EG-based copper oxide nanofluids increase with volume fraction due to the active Brownian motion of the nanoparticles, i.e., nanoconvection.