• Journal of Environmental Science International
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• v.26 no.11
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• pp.1297-1306
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• 2017

This study identified physical characteristics and aerosol particle sources of $PM_{10}$ and $PM_{2.5}$ in the industrial complex of Busan Metropolitan City, Korea. Samples of $PM_{10}$, $PM_{2.5}$ and also soil, were collected in several areas during the year of 2012 to investigate elemental composition. A URG cyclone sampler was used for collection. The samples were collected according to each experimental condition, and the analysis method of SEM-EDX was used to determine the concentration of each metallic element. The comparative analysis indicated that their mass concentration ranged from 1% to 3%. The elements in the industrial region that were above 10% were Si, Al, Fe, and Ca. Those below 5% were Na, Mg, and S. The remaining elements (1% of total mass) consisted of elements such as Ni, Co, Br and Pb. Finally, a statistical tool was applied to the elemental results to identify each source for the industrial region. From a principal components analysis (SPSS, Ver 20.0) performed to analyze the possible sources of $PM_{10}$ in the industrial region, five main factors were determined. Factor 1 (Si, Al), which accounted for 15.8% of the total variance, was mostly affected by soil and dust from manufacturing facilities nearby, Factors 2 (Cu, Ni), 3 (Zn, Pb), and 4 (Mn, Fe), which also accounted for some of variance, were mainly related to iron, non-ferrous metals, and other industrial manufacturing sources. Also, five factors determined to access possible sources of $PM_{2.5}$, Factor 1 (Na, S), accounted for 13.5% of the total variance and was affected by sea-salt particles and fuel incineration sources, and Factors 2 (Ti, Mn), 3 (Pb, Cl), 4 (K, Al) also explained significant proportions of the variance. Theses factors mean that the $PM_{2.5}$ emission sources may be considered as sources of incineration, and metals, and non-ferrous manufacturing industries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.674-682
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• 2018

Large industrial motors require a large area because of the high risk of shutdown accidents and large industrial accidents due to the lowering of the dielectric strength of the armature windings and overheating problems. Therefore, there is a demand for a large-capacity motor that has small size, light weight, and excellent dielectric strength compared with conventional motors. Superconducting motors have advantages of high efficiency and output power, low size, low weight, and improved stability. This results from greatly increasing the magnetic field generation by using superconductive field coils in rotating machines such as generators and motors. It is very important to design and analyze the cooling system to lower the critical temperature of the wires to achieve superconducting performance. In this study, a field loss analysis and low-temperature heat transfer analysis of the cooling system were performed through the conceptual design of a 100-HP high-temperature superconducting synchronous motor. The field loss analysis shows that a uniform pore magnetic flux density appears when high-temperature superconducting wire is used. The low-temperature heat transfer analysis for gaseous neon and liquid neon showed that a flow rate of 1 kg/min of liquid neon is suitable for maintaining low-temperature stability of the high-temperature superconducting wire.

• Journal of Plant Biotechnology
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• v.43 no.2
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• pp.231-239
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• 2016

To study the transcript levels of epigenetically regulated genes in tobacco, we have developed a transgenic line OX1 overexpressing NtROS2a gene encoding cytosine DNA demethylation and a RNAi plant line RNAi13. It has been reported that salt- and $H_2O_2$-stress tolerance of these transgenic lines are enhanced with various phenotypic characters (Lee et al. 2015). In this paper, we conducted microarray analysis with Agilent Tobacco 4 x 44K oligo chip by using overexpression line OX1, RNAi plant line RNAi 13, and wild type plant WT. Differentially expressed genes (DEGs) related to metabolism, nutrient supply, and various stressed were up-regulated by approximately 1.5- to 80- fold. DEGs related to co-enzymes, metabolism, and methylation functional genes were down-regulated by approximately 0.03- to 0.7- fold. qRT-PCR analysis showed that the transcript levels of several candidate genes in OX1 and RNAi lines were significantly (p < 0.05) higher than those in WT, such as genes encoding KH domain-containing protein, MADS-box protein, and Zinc phosphodiesterase ELAC protein. On the other hand, several genes such as those encoding pentatricopeptide (PPR) repeat-containing protein, histone deacetylase HDAC3 protein, and protein kinase were decreased by approximately 0.4- to 1.0- fold. This study showed that NtROS2a gene encoding DNA glycosylase related to demethylation could regulate adaptive response of tobacco at transcriptional level.

• Journal of Life Science
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• v.23 no.3
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• pp.406-414
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• 2013

The influence of a gradual increase in salinity on the diversity of aquatic bacterial in rivers was demonstrated. The denaturing gradient gel electrophoresis (DGGE) was used to analyze the bacterial community shift downstream in the Hyeongsan River until it joins the open ocean. Four water samples were taken from the river showing the salinity gradients of 0.02%, 1.48%, 2.63%, and 3.62%. The samples were collected from four arbitrary stations in 2.91 km intervals on average, and a DGGE analysis was performed. Based on the results of this analysis, phylogenetic similarity identification, tree analysis, and a comparison of each station were performed. The results strongly suggested that the response of the bacterial community response was concomitant to gradual changes in salinity, which implies that salt concentration is a major factor in shifting the microbiota in aquatic habitats. The results also imply a huge diversity in a relatively small area upstream from the river mouth, compared to that in open oceans or coastal regions. Therefore, areas downstream towards a river mouth or delta are could be good starting points in the search for new bacterial species and strains ("biotypes").

• Journal of the Korean Chemical Society
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• v.66 no.2
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• pp.124-135
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• 2022

The purpose of this study was to analyze the chemisry education contents of South Korea and North Korea for understanding chemistry education of North Korea. Chemistry education in South and North Korea was investigated in terms of learning period and learning quantaty. Especially, what content North Korea learned prior to South Korea and what contents learned more were analyzed. The subjects of this study were South Korean 2015 revised National Science Curriculum and North Korean science textbooks in Kim Jong-un era. The North Korean textbooks analyzed are 'Nature' for North Korean elementary school 3, 'Natural Science' for North Korean middle school 1 and 2, and 'Chemistry' for North Korean high school 1 and 2. The analysis results are as follows. First, the content elements to be learned in advance in North Korean textbooks were density, oxidation and reduction, battery, and atomic weight. Second, the content elements additionally learned in North Korean textbooks include separation of mixtures, fuels, oxidation and reduction, metals, organic and inorganic substances, metals and non-metal oxides and hydroxides, inorganic substances used as fertilizers, nutritional substances, and salt reaction and utilization, atomic orbitals, hybridization of orbitals, coordination bonds and complexes. As a future research task, a qualitative analysis of the elements of North Korean chemistry, the activities of textbooks, and an experimental analysis were proposed.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E1
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• pp.29-39
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• 2003

The 10-day interval basis measurements of precipitation samples at Yangyang, the rural and coastal area on the eastern coast of the Korea peninsula were accomplished for understanding the precipitation chemistry and the temporal variations of major ions September 1991 to February 1997. The precipitation was slightly acidic, and 37% of the samples in winter were pH less than 4.5. The concentrations of cations were found on the order $Na^+\;>\;{NH_4}^+\;>\;Ca^{2+}\;>\;Mg^{2+}\;>\;K^+$ and those of anions followed the pattern $Cl^-\;>\;{SO_4}^{2-}\;>\;{NO_3}^-$. Neglecting sea salt components, the major ions controlling precipitation chemistry were nss-${SO_4}^{2-}$ and ${NO_3}^-$ in anion and ${NH_4}^+$ and nss-$Ca^{2+}$ in cation. Concentrations of these ions were lower than those measured at urban sites in Korea, but were higher than those measured in Japan. Most of nss-${SO_4}^{2-}$ and ${NO_3}^-$ were neutralized by ammonia and calcium species, especially alkaline soil particles in spring and ammonia gas in other seasons. Considering also the annual value of ［nss -${SO_4}^{2-}$］/［${NO_3}^-$］ ratio of 2.62 and the neutralizing factors, ammonium sulphate compounds were dominant. Annual mean concentrations of these ions showed relatively small fluctuations, while larger seasonal variations were observed with higher levels in spring and winter. Precipitation amount, influence extent of acidic gases and alkaline particles long-range transported from China continent, and energy consumption pattern in each season might be able to explain this seasonal trend.sonal trend.

• Journal of Plant Biotechnology
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• v.4 no.3
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• pp.117-122
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• 2002

Cotton Glutathione S-Transferase(GST: EC 2.5.1.18) was cloned and Gh-5 cDNA was overexpressed in tobacco (Nicotiana tabacum) plants. The transformation of cotton GST in tobacco plant was confirmed by northern blot analysis. Type I and Type II transcript patterns were identified in Gh-5 transgenic tobacco plants. Type I transcripts was only discussed in this paper. Glutathione and 1-chloro-2,4-dinitrobenzene (CDNB) were used as the substrates, and the activity of GST in the type I transgenic plants was about 2.5-fold higher than the non-expressers and wild type tobacco plants. The expression of cotton GST in tobacco plants proved that Gh-5 could be translated into functional protein. Type I transgenic plants produced functional GST in the cells. Type I showed higher GST specific activity than Type II in the transgenic plants. Control and transgenic seedlings were grown in the growth chamber and under the light at 15$^{\circ}C$, and the effects of cotton GST in the seedlings was evaluated. The growth rate of Gh-5 overexpressors was better than the control and non-transgenic tobacco plants. Salinity tolerance was also analyzed on the seeds of transgenic plants. Seeds of Gh-5 overexpressors and the wild type tobacco seedlings were germinated and grown at 0, 50, 100, 150, and 200 mM NaCl solution. Gh-5 transgenic seedlings showed higher growth rate over control seedlings at both 50 and 100 mM NaCl solution. But at 0, 150, and 200 mM NaCl concentration, the difference in growth rate was not detected.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.454-458
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• 1997

Two human liver UDP-glucuronosyltransferase cDNA clones, HLUG25 and UDPGTh2 were previously shown to encode isozymes active in the glucuronidation of hyodeoxycholic acid (HDCA) and certain estrogen derivatives (e.g., estriol and 3,4-catechol estrogens), respectively. in this study we have found that the UDPGTh2-encoded isoform (UDPGTh2) and HLUG25-encoded isoform (UDPGThl) have parallel aglycone specificities. When expressed in COS 1 cells, each isoform metabolized three types of dihydroxy- or trihydroxy-substituted ring structures, including the 3,4-catechol estrogen (4-hydroxyestrone), estriol, 17-epiestriol, and HDCA, but the UDPGTh2 isozyme was 100-fold more efficient than UDPGTh1. UDPGTh1 and UDPGTh2 were 86% identical overall (76 differences out of 528 amino acids), including 55 differences in the first 300 amino acids of the amino terminus, a domain which conferred the substrate specificity. The data indicated that a high level of conservation in the amino terminus was not required for the preservation of substrate selectivity. Analysis of glucuronidation activity encoded by UDPGTh1/UDPGTh2 chimeric cDNA constructed at their common restriction sites, Sac I (codon 297), Nco I (codon 385), and Hha I (codon 469), showed that nine amino acids between residues 385 and 469 were important for catalytic efficiency, suggesting that this region represented a domain which was critical for the catalysis but distinct from that responsible for aglycone-selection. These data indicate that UDPGTh2 is a primary isoform responsible for the detoxification of the bile salt intermediate as well as the active estrogen intermediates.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.133-146
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• 1999

Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.

• Journal of Welding and Joining
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• v.34 no.3
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• pp.61-68
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• 2016

Characteristics of dissimilar metal welds between alloy steel ASTM A387 Gr. 91 and carbon steel ASTM A516 Gr.70 made with Flux cored arc welding(FCAW) have been evaluated in terms of microstructure, mechanical strength, chemical analysis by EDS as well as corrosion test. Three heat inputs of 15.0, 22.5, 30.0kJ/cm were employed to make joints of dissimilar metals with E91T1-B9C wire. Post-weld heat treatment was carried out at $750^{\circ}C$ for 2.5 h. Based on microstructural examination, tempered martensite and lower bainite were formed in first layer of weld metal. The amount of tempered martensite was decreased and the amount of lower bainite was increased with increasing heat input and layer. Heat affected zone of alloy steel showed the highest hardness due to the formation of tempered Martensite and lower Bainite. Tensile strengths of dissimilar welds decreased with increasing heat inputs. Dissimilar welds seemed to have a good hot cracking resistance due to the low HCS index below 4. The salt spray test of dissimilar metals showed that the corrosion rate increased with increasing heat inputs due to the increase of the amount of lower Bainite.