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Mechanical and electrochemical characteristics evaluation in annealing treatment for ship material

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中国有色金属学会会刊：英文版 2009年第B09期19卷 40-44页

作者： Seok-Ki jang Young-jae JEONG Seong-Jong KIM Division of Marine Engineering Mokpo Maritime University Jeonnam Techno Park

The effect of heat treatment on the electrochemical and mechanical properties of SS400 steel was investigated, and the effects of annealing conditions on notched specimens subjected to the slow strain rate test (SSRT) were studied. The results show that no correlations are observed among the maximum tensile strength, yield strength, and stress corrosion cracking. In contrast, the elongation and time-to-fracture are improved with stress-relieving annealing compared with the as-received condition. The elongation, time-to-fracture, and number of dimples increase with annealing heat treatment.

关键词：退火处理电化学船舶材料特性评价机械 SS400钢应力腐蚀开裂消除应力退火

Interplay between ABA and GA Modulates the Timing of Asymmetric Cell Divisions in the Arabidopsis Root Ground Tissue

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Molecular Plant 2016年第6期9卷 870-884页

作者： Shin Ae Lee Sejeong jang eun Kyung Yoon Jung-Ok Heo Kwang Suk Chang Ji Won Choi Souvik Dhar Gyuree Kim Jeong-eun Choe jae Bok Heo Chian Kwon jae-Heung Ko Yong-Sic Hwang Jun Lim Department of Systems Biotechnology Konkuk University Seour 05029 Korea Department of Molecular Biotechnology Dong-A University Busan 49201 Korea Department of Molecular Biology Dankook University Yongin 16890 Korea Department of Plant and Environmental New Resources Kyung Hee University Yongin 17104 Korea These authors contributed equally to this article. Present address: The Sainsbury Laboratory University of Cambridge Cambridge CB2 1LR United Kingdom Present address: Department of Life Science Research Institute for Natural Sciences Hanyang University Seoul 04763 Korea

In multicellular organisms, controlling the timing and extent of asymmetric cell divisions （ACDs） is crucial for correct patterning. During post-embryonic root development in Arabidopsis thaliana, ground tissue （GT） maturation involves an additional ACD of the endodermis, which generates two different tissues： the endo- dermis （inner） and the middle cortex （outer）. It has been reported that the abscisic acid （ABA） and gibberellin （GA） pathways are involved in middle cortex （MC） formation. However, the molecular mechanisms under- lying the interaction between ABA and GA during GT maturation remain largely unknown. Through transcriptome analyses, we identified a previously uncharacterized C2H2-type zinc finger gene, whose expression is regulated by GA and ABA, thus named GAZ （GA- AND ABA-RESPONSIVE ZINC FINGER）. Seedlings ectopically overexpressing GAZ （GAZ-OX） were sensitive to ABA and GA during MC formation, whereas GAZ-SRDX and RNAi seedlings displayed opposite phenotypes. In addition, our results indicated that GAZ was involved in the transcriptional regulation of ABA and GA homeostasis. In agreement with pre- vious studies that ABA and GA coordinate to control the timing of MC formation, we also confirmed the unique interplay between ABA and GA and identified factors and regulatory networks bridging the two hor- mone pathways during GT maturation of the Arabidopsis root.

关键词： ABA GA GRAS ground tissue root development transcription factor

Mechanical strength and corrosion resistance of Al-additive friction stir welded AZ31B joints

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Journal of Magnesium and Alloys 2023年第5期11卷 1519-1535页

作者： jae-Yeon Kim eun-Woo Kim Dong-O Kim eun-Kyo Ju Ji-eun Lee jaeheon Lee Jai-Won Byeon Mining Engineering Department Colorado School of MinesGoldenCO 80401USA Department of Materials Science and Engineering Seoul National University of Science and TechnologySeoul 01811Republic of Korea

Compared to other structural alloys,magnesium alloys have a relatively poor corrosion resistance and low mechanical strength,which can be further deteriorated when these alloys are subjected to joining processes using the existing joining ***,we propose for the first time an additive friction stir-welding(AFSW)using fine Al powder as an additive to improve the mechanical strength as well as corrosion resistance of AZ31B weld *** is a solid-state welding method of forming a high-Al AZ31B joint via an in-situ reaction between pure Al powders filled in a machined groove and the AZ31B *** optimize the process parameters,AFSW was performed under different rotational and transverse speeds,and number of passes,using tools with a square or screw *** particular,to fabricate a weld zone,where the Al was homogenously dispersed,the effects of the groove shape were investigated using three types of grooves:surface one-line groove,surface-symmetric grooves,and inserted symmetric *** homogenous and defect-less AFS-welded AZ31B joint was successfully fabricated with the following optimal parameters:1400 rpm,25 mm/min,four passes,inserted symmetric grooves,and the tool with a square *** AFSW fully dissolved the additive Al intoα-Mg and in-situ precipitated Mg_(17)Al_(12)particles,which was confirmed via scanning electron microscopy,transmission electron microscope,and X-ray diffraction *** microhardness,joint efficiency,and elongation at the fracture point of the AFS-welded AZ31B joint were 80 HV,101%,and 8.9%,*** values are higher than those obtained for the FS-welded AZ31 joint in previous *** corrosion resistance of the AFS-welded AZ31B joint,evaluated via hydrogen evolution measurements and potentiodynamic polarization tests,was enhanced to 55%relative to the FS-welded AZ31B joint.

关键词： AZ31B magnesium alloy Additive friction stir-welding In-situ reaction Mg_(17)Al_(12)particles Joint efficiency Corrosion resistance

Effects of Wind Fences on the Wind Environment around jang Bogo Antarctic Research Station

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Advances in Atmospheric Sciences 2017年第12期34卷 1404-1414页

作者： jang-Woon WANG jae-Jin KIM Wonsik CHOI Da-Som MUN Jung-eun KANG Hataek KWON Jin-Soo KIM Kyung-Soo HAN Department of Environmental Atmospheric Sciences Pukyong National University 45Yongso-ro Korea Polar Research Institute 26 Songdomirae-ro Yeonsu-gu Department of Spatial Information Engineering Pukyong National University 45Yongso-ro

This study investigated the flow characteristics altered by jang Bogo Antarctic Research Station using computational fluid dynamics(CFD) modeling. The topography and buildings around jang Bogo Station were constructed with computeraided-design data in the CFD model domain. We simulated 16 cases with different inflow directions, and compared the flow characteristics with and without jang Bogo Station for each inflow direction. The wind data recorded by the site’s automatic weather station(AWS) were used for comparison. Wind rose analysis showed that the wind speed and direction after the construction of jang Bogo Station were quite different from those before construction. We also investigated how virtual wind fences would modify the flow patterns, changing the distance of the fence from the station as well as the porosity of the fence. For westerly inflows, when the AWS was downwind of jang Bogo Station, the decrease in wind speed was maximized(-81% for west-northwesterly). The wind speed reduction was also greater as the distance of the fence was closer to jang Bogo Station. With the same distance, the fence with medium porosity(25%–33%) maximized the wind speed *** results suggest that the location and material of the wind fence should be selected carefully, or AWS data should be interpreted cautiously, for particular prevailing wind directions.

关键词： jang Bogo Antarctic Research Station CFD model observation environment wind fence porosity

Efficacy of Helicobacter pylori eradication for the prevention of metachronous gastric cancer after endoscopic resection for early gastric cancer

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World Journal of Gastroenterology 2014年第11期20卷 2760-2764页

作者： jae Young jang Hoon Jai Chun Division of Gastroenterology Department of Internal MedicineCollege of MedicineKyung Hee UniversitySeoul 136-705South Korea Division of Gastroenterology and Hepatology Department of Internal MedicineInstitute of Digestive Disease and NutritionKorea University College of MedicineSeoul 136-705South Korea

Helicobacter pylori(***)plays an important role in gastric carcinogenesis,as the majority of gastric cancers develop from ***-infected gastric *** rate of early gastric cancer diagnosis has increased in Japan and Korea,where *** infection and gastric cancer are highly *** intestinal-type gastric cancer without concomitant lymph node metastasis is usually treated by endoscopic *** metachronous gastric cancers often develop because atrophic mucosa left untreated after endoscopic treatment confers a high risk of gastric *** efficacy of *** eradication for the prevention of metachronous gastric cancer remains ***,in patients who undergo endoscopic resection of early gastric cancer,*** eradication is recommended to suppress or delay metachronous gastric *** and regularly scheduled endoscopy should be performed to detect minute metachronous gastric cancer after endoscopic resection.

关键词： Helicobacter pylori Gastric cancer Endoscopic resection Metachronous cancer

Bowel preparations as quality indicators for colonoscopy

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World Journal of Gastroenterology 2014年第11期20卷 2746-2750页

作者： jae Young jang Hoon Jai Chun Division of Gastroenterology Department of Internal MedicineCollege of MedicineKyung Hee UniversitySeoul 130-701South Korea Division of Gastroenterology and Hepatology Department of Internal MedicineInstitute of Digestive Disease and NutritionKorea University College of MedicineSeoul 136-705South Korea

Colonoscopy is the principal investigative procedure for colorectal neoplasms because it can detect and remove most precancerous *** effectiveness of colonoscopy depends on the quality of the *** preparation is an essential part of high-quality colonoscopies because only an optimal colonic cleansing allows the colonoscopist to clearly view the entire colonic mucosa and to identify any polyps or other *** bowel preparation not only prolongs the overall procedure time,decreases the cecal intubation rate,and increases the costs associated with colonoscopy but also increases the risk of missing polyps or adenomas during the ***,a repeat examination or a shorter colonoscopy follow-up interval may be suitable strategies for a patient with suboptimal bowel preparation.

关键词： Colonoscopy Colorectal neoplasm Bower preparation Quality

The use of artificial nest boxes by Siberian flying squirrels (Pteromys volans) in South Korea

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Journal of Forestry Research 2019年第3期30卷 1131-1137页

作者： Jong-U Kim Woo-shin Lee eun-jae Lee Department of Forest Sciences Seoul National University Seoul 08826Republic of Korea Urban Planning Research Division Daejeon Sejong Research InstituteDaejeon 34863Republic of Korea

In this study, we examined the use of artificial nest boxes by Siberian flying squirrels (Pteromys volans) in three coniferous and mixed forests in Gangwon Province, South Korea. Six hundred and twelve boxes with different sized entry holes (ranging from 3 to 7 cm in diameter) were placed in the forests between 2004 and 2009. Pteromys volans used nine boxes in the coniferous forests and two boxes in the mixed forests. The squirrels only used boxes with entrance holes measuring 3.5, 4, and 5 cm in diameter, showing a strong and moderate preference for boxes with 5 and 4-cm holes, respectively, and a strong avoidance for boxes with 3- and 7-cm holes. Therefore, we suggest placing artificial nest boxes with entrance holes 5 cm in diameter to encourage breeding activity. Most nests made in the artificial boxes were composed of fibrous materials from woody vines. We recommend placing artificial nest boxes with holes of 5-cm diameter in coniferous forests, which support dense populations of P. volans, to survey whether this approach would positively affect the breeding habits and population maintenance of this species.

关键词： Artificial nest box Coniferous forests Nest materials Siberian flying squirrel Woody vines

Significance of adverse outcome pathways in biomarker-based environmental risk assessment in aquatic organisms

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Journal of Environmental Sciences 2015年第9期27卷 115-127页

作者： Jin Wuk Lee eun-Ji Won Sheikh Raisuddin jae-Seong Lee Department of Biological Science College of Science Sungkyunkwan University Department of Medical Elementology and Toxicology Hamdard University

In environmental risk assessments（ERA）, biomarkers have been widely used as an early warning signal of environmental contamination. However, biomarker responses have limitation due to its low relevance to adverse outcomes（e.g., fluctuations in community structure, decreases in population size, and other similar ecobiologically relevant indicators of community structure and function）. To mitigate these limitations, the concept of adverse outcome pathways（AOPs） was developed. An AOP is an analytical, sequentially progressive pathway that links a molecular initiating event（MIE） to an adverse outcome. Recently, AOPs have been recognized as a potential informational tool by which the implications of molecular biomarkers in ERA can be better understood. To demonstrate the utility of AOPs in biomarker-based ERA, here we discuss a series of three different biological repercussions caused by exposure to benzo（a）pyrene（Ba P）, silver nanoparticles（Ag NPs）, and selenium（Se）. Using mainly aquatic invertebrates and selected vertebrates as model species, we focus on the development of the AOP concept. Aquatic organisms are suitable bioindicator species whose entire lifespans can be observed over a short period; moreover, these species can be studied on the molecular and population ***, interspecific differences between aquatic organisms are important to consider in an AOP framework, since these differences are an integral part of the natural *** development of an environmental pollutant-mediated AOP may enable a better understanding of the effects of environmental pollutants in different scenarios in the diverse community of an ecosystem.

关键词： Adverse outcome pathway Biomarker Omics Environmental risk assessment Aquatic organisms Interspecific difference

Segmented tomographic evaluation of structural degradation of carbon support in proton exchange membrane fuel cells

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Journal of Energy Chemistry 2022年第11期31卷 359-367,I0010页

作者： Jung A.Hong Min-Hyoung Jung Sung Yong Cho eun-Byeol Park Daehee Yang Young-Hoon Kim Sang-Hyeok Yang Woo-Sung jang jae Hyuck jang Hyo June Lee Sungchul Lee Hu Young Jeong Young-Min Kim Department of Energy Science Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Fuel Cell Core Parts Development Cell Hyundai Mobis Co.Ltd.Uiwang 16082Republic of Korea Electron Microscopy&Spectroscopy Team Korea Basic Science Institute(KBSI)Daejeon 34133Republic of Korea Graduate School of Semiconductor Materials and Devices Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea

The variation of the three-dimensional(3D)structure of the membrane electrode of a fuel cell during proton exchange cycling involves the corrosion/compaction of the carbon *** increasing degradation of the carbon structure continuously reduces the electrocatalytic performance of proton exchange membrane fuel cells(PEM-FCs).This phenomenon can be explained by performing 3D tomographic analysis at the ***,conventional tomographic approaches which present limited experimental feasibility,cannot perform such evaluation and have not provided sufficient structural information with statistical significance thus ***,a reliable methodology is required for the 3D geometrical evaluation of the carbon ***,we propose a segmented tomographic approach which employs pore network analysis that enables the visualization of the geometrical parameters corresponding to the porous carbon structure at a high *** approach can be utilized to evaluate the 3D structural degradation of the porous carbon structure after cycling in terms of local surface area,pore size distribution,and their 3D *** geometrical parameters of the carbon body were demonstrated to be substantially reduced owing to the cycling-induced *** information enables a deeper understanding of the degradation phenomenon of carbon supports and can contribute to the development of stable PEM-FC electrodes.

关键词： Electron tomography Fuel cell Proton exchange membrane Membrane electrode assembly Carbon corrosion