• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.55-61
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• 2003

The objective of this study was to investigate the characteristics of nitrate removal by conducting the column test in order to see the performance of surfactant modified zeolite (SMZ) as a permeable reactive barrier material. The prediction of nitrate removal was tested using the one-dimensional advective-dispersive model fitted to the experimental breakthrough curve. A methodology for scaling up to in-situ permeable reactive barrier was also proposed. The breakthrough of nitrate in the column packed with SMZ was well predicted using linear equilibrium adsorption model. The breakthrough time and half-life obtained by breakthrough experiment with variation of flowrates were decreased with the increase of flowrates. When 10㎥/day of groundwater containing the 50 mg/l of nitrate is to be treated to satisfy the potable water quality criteria (10 mg/l) by SMZ reactive barrier, 300 tons of SMZ and about 6 years of breakthrough time will be required, suggesting that 165 million wons are needed as barrier material expenses in each 6 years besides the initial design and construction expenses and the minimal monitoring and maintenance expenses.

• Journal of Korea Foundry Society
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• v.35 no.3
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• pp.53-61
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• 2015

Effects of Zn addition on the microstructure and corrosion behavior of Mg-8%Al-(0-1)%Zn casting alloys were investigated. With increasing Zn content, the amount of ${\beta}(Mg_{17}Al_{12})$ phase increased, while ${\alpha}$-(Mg) dendritic cell size became reduced. The corrosion rate decreased continuously with the increase in the Zn content. The evaluation of the microstructural evolution indicates that the improved barrier effect of ${\beta}$ particles formed more continuously along the dendritic cell boundaries and the incorporation of more ZnO into the surface corrosion product, by which the absorption of $Cl^-$ ions is impeded, are responsible for the better corrosion resistance in relation to the Zn addition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1563-1568
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• 2003

The introduction of invasive marine species of living things into new environments by ship's ballast water, attached to ships' hulls and via other vectors has been identified as one of the four greatest threats to the world's oceans by Global Environment Facility(GEF). Making use of the new technology of alpha-AL$_2$O$_3$ dielectric barrier layer, the strong electric-field gas discharge was introduced and obtained between micro-gap electrodes at high pressure (∼105㎩) of $O_2$ in air and $H_2O$ in seawater. The mixed air with $H_2O$ could be ionized and dissociated into large numbers of activated particles of OH, $O_2$＋, O(1D), HO$_2$ and so on, and then dissolved into the ballast water to form dissolved hydroxyl radical with the concentration of ∼20mg/L. Therefore, the invasive marine species was treated effectively through the hydroxyl radical dissolved pipeline of ballast water by strong electric -field discharge.

• Journal of Power System Engineering
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• v.17 no.5
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• pp.13-22
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• 2013

This paper reports the investigation of the physical and chemical characteristics of the prepared 3Pt-2MgO-$3ZrO_2$-$2CeO_2/Al_2O_3$ DOC, based on its hydrothermal aging. As a result of impregnating and reducing the $H_2PtCl_6$ $6H_2O$ precursor on a ${\gamma}-Al_2O_3$ basis, it was well dispersed into small particles with the range 2-3nm. This was because the $Al_2O_3$ acted as a barrier to prevent movement of the catalyst particles. For a hydrothermally aged catalyst for 9h at $700^{\circ}C$, its performance when purifying harmful gases decreased compared to a fresh catalyst, but its specific surface area was at the same level. This was because the performance of the catalyst was reduced by the sintering of the precious metal Pt, rather than by washcoat sintering and pore clogging. For an excessively hydrothermally aged catalyst for 9h at $850^{\circ}C$, Pt grew into an approximately 50nm class, formed a cluster compared to a fresh catalyst. The $CeO_2$ promoters also formed clusters among components of the same type, reducing their specific surface area to $114m^2/g$, which was 14% less than a fresh catalyst.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.49-51
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• 2002

In this thesis, Josephson junction using high-Tc superconducting multi-layer thin film has been fabricated by on-axis RF magnetron sputtering method. And, the characterizations were performed by X-ray diffraction, SEM and the measuring system of critical current density. The physical properties of multi-layer superconducting thin films were also analyzed with the measured results. To fabricate the multi-layer superconducting thin films, the optimum partial pressure of Argon and Oxgen and the temperature of substrate were measured. Also, YBaCuO thin film was grown on MgO and $SrTiO_3$ substrates by rf-sputtering and LGO thin film of 30 A was epitaxially grown on the YBaCuO thin film as a josephson junction with the same condition. The schottky barrier at the contact surface between YBaCuO/LGO and YBaCuO/Au and the energy gap of 0.5 ${\sim}$ 0.6 mV in Nb were observed from the dI/dV-V of YBaCuO/LGO/Au/Nb and YBaCuO/Au/Nb.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.330-330
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• 2022

In recent studies, cold plasma has been used to induce exudation of polyphenols and flavonoids from food materials, leading to enhancement of functional properties. And it is known that polyphenols interact with inflammation related metabolism. The objectives of this study were to investigate the effects of cold plasma treatments on the increase of total phenolic content (TPC), total flavonoid content (TFC), and anti-inflammatory activities of 'Sinpalkwang' peanut (Arachis hypogaea L.) hull. Plasma treatments were carried out using a dielectric barrier discharge gas exchange system at different radicals and temperatures (O₃-25℃, O₃-150℃, NO_x-150℃). Significant differences in TPC, TFC, and inflammatory mediator such as nitric oxide (NO) and tumor necrosis factor a (TNF-α) in lipopolysaccharide stimulated Raw 264.7 macrophages were observed between treated and non-treated peanut hull samples (p < 0.001). Cold plasma treated samples showed higher content (TPC: 2.87-2.93 mg/g sample, TFC: 0.96-0.98 mg/g sample) than non-treated sample (TPC: 2.47 mg/g sample, TFC: 0.78 mg/g sample). Cold plasma treated samples showed lower content of NO (3.3-5.0 uM) and TNF-α (141.4-162.2 ng/mL) than non-treated sample (NO: 11.1 uM, TNF-α: 210.2 ng/mL). This study suggests that cold plasma has potential to improve functionalities of food materials and that cold plasma treated peanut hull can be used as immune enhancing materials.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.38-42
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• 2004

A pilot-scale experiment for the treatment of red tide in the enclosure was done in sea area of Shandong Province, P. R. China on Aug. 25, 2002. With the method of strong dielectric barrier discharge in microgap, $O_2$in air and $H_2O$ in seawater are ionized and dissociated into large numbers of OHㆍradicals, and then dissolved into a part of seawater to form OHㆍsolution of high concentration. With OH' concentration of 0.68mg/L, the kill efficiencies of 29 kinds of red tide organisms such as Chaetoceros lorenzianus and so on reached 99.89%, in which the kill efficiencies of bacterium and vibrio were 100%, and that of Gonyaulax cysts and Prei. Cysts were up to 100%. At the same time, the content of chlorophyll-a was decreased into the lowest limit of test. DO saturation of seawater was greatly increased to 100% because the residual OHㆍradical was decomposed into $H_2O$ and $O_2$after 20 minutes, Therefore the treatment of red tide using OHㆍradicals is a kind of advanced oxidation technology, which realizes zero pollution, zero emission and zero residual in the process of the production of OHㆍradicals and the treatment of red tide.

• International Journal of Industrial Entomology and Biomaterials
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• v.38 no.2
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• pp.25-30
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• 2019

Atmospheric-pressure plasma technique is a technology for sterilizing agricultural product. In this study, dielectric barrier discharge plasma was applied to silkworm powder for 1 to 5 h with less than 2 ppm of $O_3$ and $NO_2$. Quantitative compositions including proximate contents, mineral and heavy metal contents, fatty acids, vitamins, and DNJ contents were measured. Proximate contents of silkworm powder were protein (57.2%), fat (9.9%), fiber (4.6%), ash (10.1%), and moisture (5.7%). These compositions were not affected by the treatment of plasma. Silkworm powder has 5 abundant minerals potassium (K), phosphorus (P), sulfur (S), calcium (Ca), and magnesium (Mg). Among these minerals, plasma treatment decreased the contents of P and S sharply from 732.3 to 176.8, and 492.7 to 185.2 mg/100g, respectively. Heavy metal contents including lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg) were not detected in the silkworm powder. Five vitamins such as ascorbic acid (13.6 mg/100g), riboflavin (5.4 mg/100g), ${\beta}$-carotene (1.8 mg/100g), niacin (0.6 mg/100g), and thiamine (0.4 mg/100g) were not significantly changed by plasma treatment. Silkworm powder is composed of 30 parts saturated fatty acids and 70 parts unsaturated ones. The fatty acid composition was not significantly changed by plasma treatment. The DNJ content of silkworm powder (3.72 mg/g) was also nearly constant within the experimental condition of plasma treatment.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.67-70
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• 2022

In order to prevent water vapor and oxygen permeation in the organic light emitting diodes (OLED), Al₂O₃ thin-film encapsulation (TFE) technology were investigated. Atomic layer deposition (ALD) method was used for making the Al₂O₃ TFE layer because it has superior barrier performance with advantages of excellent uniformity over large scales at relatively low deposition temperatures. In this study, the thickness of the Al₂O₃ layer was varied by controlling the numbers of the unit pulse cycle including Tri Methyl Aluminum(Al(CH₃)₃) injection, Ar purge, and H₂O injection. In this case, several process parameters such as injection pulse times, Ar flow rate, precursor temperature, and substrate temperatures were fixed for analysis of the effect only on the thickness of the Al₂O₃ layer. As results, at least the thickness of 39 nm was required in order to obtain the minimum WVTR of 9.04 mg/m²day per one Al₂O₃ layer and a good transmittance of 90.94 % at 550 nm wavelength.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1278-1285
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• 2008

The intestinal epithelial cell (IEC) layer of the intestinal tract makes direct contact with a number of microbiota communities, including bacteria known to have deleterious health effects. IECs possess innate protective strategies against pathogenic challenge, which primarily involve the formation of a physicochemical barrier. Intestinal tract mucins are principal components of the mucus layer on epithelial surfaces, and perform a protective function against microbial damage. However, little is currently known regarding the interactions between probiotics/pathogens and epithelial cell mucins. The principal objective of this study was to determine the effects of Lactobacillus on the upregulation of MUC2 mucin and the subsequent inhibition of E. coli O157:H7 attachment to epithelial cells. In the current study, the attachment of E. coli O157:H7 to HT-29 intestinal epithelial cells was inhibited significantly by L. acidophilus A4 and its cell extracts. It is also important to note that the expression of MUC2 mucin was increased as the result of the addition of L. acidophilus A4 cell extracts (10.0 mg/ml), which also induced a significant reduction in the degree to which E. coli O157:H7 attached to epithelial cells. In addition, the mRNA levels of IL-8, IL-1$\beta$, and TNF-$\alpha$ in HT-29 cells were significantly induced by treatment with L. acidophilus A4 extracts. These results indicate that MUC2 mucin and cytokines are important regulatory factors in the immune systems of the gut, and that selected lactobacilli may be able to induce the upregulation of MUC2 mucin and specific cytokines, thereby inhibiting the attachment of E. coli O157:H7.