• Korean Journal of Materials Research
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• v.16 no.2
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• pp.99-105
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• 2006

This paper reports an improved bonding method using the IPA (isopropyl alcohol) assisted low-temperature bonding process for the PMMA (polymethylmethacrylate) micro CE (capillary electrophoresis) chip. There is a problem about channel deformations during the conventional processes such as thermal bonding and solvent bonding methods. The bonding test using an IPA showed good results without channel deformations over 4 inch PMMA wafer at $60^{\circ}C$ and 1.3 bar for 10 minutes. The mechanism of IPA bonding was attributed to the formation of a small amount of vaporized acetone made from the oxidized IPA which allows to solvent bonding. To verify the usefulness of the IPA assisted low-temperature bonding process, the PMMA micro CE chip which had a $45{\mu}m$ channel height was fabricated by hot embossing process. A functional test of the fabricated CE chip was demonstrated by the separation of fluorescein and dichlorofluorescein. Any leakage of liquids was not observed during the test and the electropherogram result was successfully achieved. An IPA assisted low-temperature bonding process could be an easy and effective way to fabricate the PMMA micro CE chip and would help to increase the yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.314-321
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• 1995

Experiments were conducted to obtain information on separation of nonviable seeds from seed lots of rape, Chinese cabbage and radish, by nondestrutive ways. Seeds were artificially aged at 90% relative humidity(RH) and 45$^{\circ}C$ to get different seed qualities. Large amounts of amino acids, proteins and sinapine were leaked from the dead seeds into water in the course of 4~8 hours soaking, while high quality seeds did not leak in all crops. Percentage of normal seedlings from nonfluorescent cellulose coated seeds of rape, Chinese cabbage and radish under ultraviolet light was 96, 96 and 74%, while that of fluorescent seeds was 8, 9 and 1%, respectively. Cellulose coating and storage of Chinese cabbage and rape seeds at 60 and 75% RH for 3 months and 90% RH for 2 months did not deteriorate seed quality. But percentage of normal seedlings from nonfluorescent radish seeds stored at 60, 75 and 90% RHs for 3 months was 63, 64 and 2%, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.747-749
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• 2017

To protect financial services against danger of financial accidents and customer information leakage caused by malware, injection attack and so on, Financial Services Commission announced "Financial Networks Security Enhancement Comprehensive Plan", which suggests the guideline of protecting customer information and providing secure financial services by separating network topology and then makes the financial company use network partitioning system. In consequence of this policy, financial companies respectively chose between the physical partitioning mechanism or the logical partitioning mechanism according to their IT environment. This paper suggests an efficient infrastructure configuration plan for making the logical network partition, by comparison of a construction of traditional general equipment and an integrated HCI(Hyper Converged Infrastructure) through 'Hyper Converged' which is one of virualization techniques for developing currently, and the case study of the integrated HCI method.

• Membrane Journal
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• v.21 no.4
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• pp.321-328
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• 2011

$PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$ oxide was synthesized by soild state reaction method. Dense ceramic membrane was prepared using as-prepared powder by pressing and sintering at $1250^{\circ}C$. XRD result of membrane showed double perovskite structure. Leakage and oxygen permeation test were conducted on the membrane sealed by pyrex ring as a sealing material. Oxygen permeation was measured in the temperature range from 850 to $950^{\circ}C$. The oxygen flux of $PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$ membrane was increased with the temperature from 0.15 to $0.32mL/cm^2{\cdot}min$.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.446-454
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• 2010

CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

• Convergence Security Journal
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• v.22 no.2
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• pp.59-66
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• 2022

Recently, smart home technology has been developed with a great response due to the convenience of home automation. Smart home technology provides various services by connecting various Internet of Things (IoT) and sensors to a home network through wired/wireless networks. In addition, the smart home service easily and conveniently controls lighting, energy, environment, and door cameras through a wall pad. However, while it has become a social issue due to the recent hacking accident of wall pads, personal information leakage and privacy infringement are expected. Accordingly, it is necessary to prepare preventive and countermeasures against security vulnerability factors of wall pads. Therefore, this study expects that it can be used as basic data for future smart home application and response technology development by examining the weak causes and countermeasures related to wall pads.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.509-518
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• 2010

Purpose: Major drawbacks of conventional bone marrow stromal cells (BSCs) transplantation method are mainly caused by direct transplanted cell to host cell interactions. We hypothesized that separation of the transplanted cells by a microporous membrane might inhibit most of the potential adverse effects and induce superior effect. The purpose of the study is to determine the optimal condition of the microporous membrane. Methods: First, BSCs were placed in polyethylene terephthalate (PET) transwell inserts with 3, 8, or $12{\mu}m$ pore size, and cultured in 24 well culture plates. After 5 days, bottoms of the plates were observed for presence of attached BSCs in monolayer and cell numbers were evaluated. Second, BSCs were placed PET, polycarbonate (PCT), and mixed cellulose esters (MCE) transwell inserts with 3 and $8{\mu}m$ pore size, and cultured in 24 well culture plates. After 3 days, the supernatants of the media left in culture plate were analyzed for collagen, vascular endothelial growth factor (VEGF), platelet derived growth factor BB (PDGF-BB), and basic fibroblast growth factor (bFGF). Third, BSCs were placed in 15% and 70% of the PET membrane with $3{\mu}m$ pore size. All the experimental conditions and methods were same as the second study. Results: The optimal pore sizes to prevent BSC leakage were $3{\mu}m$ and $8{\mu}m$. The amounts of type I collagen and three growth factors tested did not show significant differences among PET, PCT, and MCE groups. However, the collagen, VEGF, and bFGF levels were much higher in the high (70%) density group than in the low (15%) density group. Conclusion: This study revealed that the optimal pore size of membrane to prevent direct BSC to recipient cell contact is in between $3{\mu}m$ and $8{\mu}m$. Membrane materials and pore sizes do not influence the collagen and growth factor passage through the membrane. The most striking factor for collagen and growth factor transport is pore density of the membrane.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.424-429
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• 2018

In this study, an expansion joint that is susceptible to waterhammer was tested for its vibration durability. The operation data for the hydraulic actuator was the expansion length of the expansion joint when the waterhammer occurred. In the case of the vibration durability test, the internal temperature status of the expansion joint was assumed to be a stress factor and a lifespan prediction model was assumed to follow the Arrhenius model. A test was carried out by increasing the internal temperature status at $30^{\circ}C$, $50^{\circ}C$, and $65^{\circ}C$. By a linear transformation of the lifespan data for each temperature, a constant value and activation energy coefficient was induced for the Arrhenius equation and verified by comparing the value of a lifetime prediction model with the experimental value at $85^{\circ}C$. The failure modes of the ongoing or finished test were leakage, bellows separation, and internal deformation. In the future, a composite lifespan prediction model, including two more stress factors, will be developed.

• Journal of Life Science
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• v.19 no.10
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• pp.1410-1416
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• 2009

The present study aims to examine the effect of turbid water on fishes in streams which branch into a turbid water area (Yeongyang-gun) and a non-turbid water area (Cheongsong-gun), and finally flow into the Imha reservoir. In a comparison of water quality, the chemical status of the water showed higher pH, DO and SS in the turbid water area than in the non-turbid water area. Also, high density of clay minerals such as vermiculite (V) and illite (I), which is from clay mineral leakage during rainfall, was detected in turbid water, resulting in an increase of turbidity. Fishes inhabiting the turbid water showed irregular spaces in gill lamella, cell separation, edema, and clubbing in epithelial tissues. Also, the gill surface showed roughness and plenty of muddy debris substances inside the gills. The Bowman's space was expanded because of contraction of the glomerulus in the Bowman's space of the kidney tissues. Antioxidant enzymes such as SOD, CAT, GPX, and GST showed higher activities in the specific tissues, muscles and kidney, of fishes living in turbid water than in the non-turbid area. We suggested that; first, the antioxidant activities were increased due to removal of harmful radicals generated in fish bodies in the turbid water area, second, long-time exposure of these histological changes in the tissues might have induced secondary lesion accompanying the inaccurate physiological constancy of fishes.

• Analytical Science and Technology
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• v.14 no.3
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• pp.274-285
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• 2001

In this study, the thermal desorption-cryofocusing-gas chromatographic(TD-C-GC) method was developed for determination of volatile organic compounds(VOCs) in ambient air and was applied at the municipal solid waste landfill sites. On-column cryofocusing was possible only with a 100 ml dewars bottle in TD-C-GC method with a stainless steel column. However, high operating pressure was needed for purging VOCs from the absorbent trap, which was able to solve by pressure programming with a electric pressure controller. By using both pressure and temperature programming brought increasing of resolution power in on-column cryofocusing method, but the high pressure caused a leakage of sample tube with repeated use. A loop cryofocusing devise was also developed and compared with the direct on-column method. In loop cryofocusing method, VOCs were concentrated on a 0.8mm i.d. loop which is located between the injector and separation column by using liquid nitrogen. In order to purge VOCs from the absorbent trap, only 0.4 psi of pressure was need in the loop cryofocusing method. Dual detection system was applied for the analysis of VOCs; a FID was used for hydrocarbons and a FPD was used for sulfur-containing compounds. Qualitative analysis was done by on-column cryofocusing GC-MS system. Among the large number of VOCs, toluene was the most abundant. Hydrogen sulfide, dimethyl sulfide, carbon disulfide, dimethyl disulfide and methyl propyl disulfide were detected at landfill site by FPD.