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Improvement of hydrogen embrittlement and stress corrosion cracking by annealing for Al-4.4Mg-0.6Mn alloy

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 17-22页

作者： Seong-Jong kim Min-Su han Seong-Kweon kim Seok-Ki JANG Division of Marine Engineering Mokpo National Maritime University Media Engineering Seoul National University of Technology

With no annealing treatment, cathodic polarization trends in 5083F A1 alloy revealed concentration polarization and activation polarization. However, the annealed specimens have lower current densities at corrosion protection potential compared to the non-annealed specimen. The results of SSRTs conducted in seawater at the applied potential range of-l.8 V to -0.5 V indicated that the maximum tensile strength, elongation, and time-to-fracture had high values at applied potentials of -0.7 to -1.4 V. The maximum tensile strength, elongation, and time-to-f？acture decreased when the potential values were beyond this range in either anodic or cathodic direction. In general, the increased shear lip caused by annealing treatment indicates elongation. Time-to-fracture would likely increase with elongation. Potentials between -0.5 V to -0.6 V were found to be in the region of stress corrosion cracking. The corrosion protection zone was determined to be -0.7 V to -J,4 V because these potential ranges produced good mechanical properties. Potential less than -1.4 V produced a fractured surface with a mixture of dimples （ductile fractures） and a quasi-cleavage pattern resulting from the effects of hydrogen gas.

关键词： annealing 5083F A1-Mg alloy corrosion seawater slow strain rate tests

A GIS-Based Framework for Real-Time Debris-Flow Hazard Assessment for Expressways in Korea

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International Journal of Disaster Risk Science 2016年第3期7卷 293-311页

作者： han-Saem kim Choong-Ki Chung Sang-Rae kim Kyung-Suk kim Earthquake Research Center Korea Institute of Geoscience and Mineral Resources Department of Civil and Environmental Engineering Seoul National University Department of Civil and Environmental Engineering Northwestern University Expressway and Transportation Research Institute Korea Expressway Corporation

Debris flows caused by heavy rainfall in mountain areas near expressways lead to severe social and economic losses and sometimes result in ***, the development of a real-time system for debris-flow hazard assessment is necessary to provide preliminary information for rapid decision making about evacuations or restoration measures, as well as to prevent secondary disasters caused by debris flows. Recently,various map-based approaches have been proposed using multi-attribute criteria and assessment methods for debrisflow susceptibilities. For the macrozonation of debris-flow hazard at a national scale, a simplified method such as the Korea Expressway Corporation(KEC) debris-flow hazard assessment method can be applied for systematic analysis based on geographic information systems(GIS) and monitoring networks. In this study, a GIS-based framework of real-time debris-flow hazard assessment for expressway sections is proposed based on the KEC debris-flow hazard assessment method. First, the KEC-based method was standardized in a systematic fashion using Arc GIS,enabling the objective and quantitative acquisition of various attribute datasets. The quantification of rainfall criteria also was considered. A safety management system for debris-flow hazard was developed based on the GIS platform. Finally, the method was applied and verified on three expressway sections in Korea. The grading standard for each individual influencing attribute was subsequently modified to more accurately assess the debris-flow hazards.

关键词： Debris-flow hazard Expressway management GIS Korea Real-time hazard assessment

Gas-Liquid Interfacial Plasma engineering under dilute nitric acid to improve hydrophilicity and OER performance of nickel foam

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Progress in Natural Science:Materials International 2022年第5期32卷 608-616页

作者： Minju kim Jihun kim Lusha Qin Sobin Mathew Youri han Oi Lun Li School of Materials Science and Engineering Pusan National University Engine Research Institute Hydrogen Energy Research Department Engine & Machinery Business Unit Hyundai Heavy Industries Co. Ltd

The world has been moving rapidly to find new eco-friendly energy sources. Water electrolysis consists of two reactions of Oxygen Evolution Reaction(OER) and Hydrogen Evolution Reaction(HER), whereas the OER is considered the rate-limiting step. The most commercialized electrode for OER in the alkaline electrolyte is Ni foam, but its original surface is hydrophobic. It is possible to accelerate the adsorption and desorption process of reactants and products during OER by adding hydrophilic functional groups such as –OH on the surface of Ni foam. In this study, a novel Gas-Liquid Interfacial Plasma(GLIP) engineering at room temperature was successfully applied to modify the Ni foam surface dilute(1 M) HNO3solution. At a current density of 400 mA cm-2,GLIP-treated Ni foam electrodes at 1 M HNO3concentrations showed OER overpotentials of 458 mV. Among all,GLIP with 1 M HNO3treatment of 30 min showed 129 mV less overpotential than the nickel foam before treatment. In summary, GLIP can be justified as an environmentally friendly and efficient surface treatment to improve the wettability and OER performance of Ni-based electrodes in water electrolysis.

关键词： Gas−liquid interfacial plasma (GLIP) Oxygen evolution reaction Water electrolysis Plasma engineering Surface treatment Ni foam Hydrophilic

Effect of ionic composition on thermal properties of energetic ionic liquids

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npj Computational Materials 2018年第1期4卷 433-442页

作者： Chihyun Park Minsu han Jinbo kim Woojae Lee Eunkyoung kim Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Korea

A model to predict the effect of ionic composition on the thermal properties of energetic ionic liquids was developed by quantitative structure-property relationship modeling,which predicted the detonation velocity,pressure,and melting temperature of energetic ionic liquids.A hybrid approach was used to determine the optimal subset of descriptors by combining regression with the genetic algorithm as an optimization *** model showed the high accuracy,reaching a correlation factor of R^(2) as 0.71,0.73 and 0.68 for the correlation between the calculated detonation velocity,pressure and melting temperature against reported *** was validated extensively and compared to the Kamlet–Jacobs *** effect of ion composition on the thermal properties of energetic ionic liquids could be quantitatively analyzed through the developed model,to give an insight for the design of new energetic ionic liquids.

关键词： thermal ionic properties

Implanting a preferential solid electrolyte interphase layer over anode electrode of lithium ion batteries for highly enhanced Li^+ diffusion properties

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Journal of Energy Chemistry 2020年第9期29卷 285-292,I0009页

作者： Ye Kyu kim Yoongon kim Jaejin Bae Hyunwoo Ahn Yuseong Noh Hyunsu han Won Bae kim Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)Nam-gu 37673PohangSouth Korea

The lithium-ion batteries are recognized as the most promising energy storage system,but it still does not meet the power requirements of electric vehicle batteries owing to low volumetric energy density with the traditional graphite electrode *** this study,we report the development of a novel electrode system fabricated by implantation of a solid electrolyte interphase(SEI)layer on the graphite *** SEI-implanted graphite electrode is made using a lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)-based electrolyte and cycled with a lithium tetrafluoroborate LiBF4-based *** new electrode system shows significantly enhanced electrochemical properties owing to the rapid and efficient diffusion of Li ions through the SEI layer between the electrolyte and *** graphite electrode with its pre-formed SEI layer achieves a reversible capacity of 357 mAh g^-1 at 0.5 C after 50 cycles,which is significantly higher than that of commercial lithium-ion battery systems constructed with LiPF6(312mAh g^-1).The resulting unique electrode system could present a new avenue in SEI research for highperformance lithium-ion batteries.

关键词： SEI layer Graphite Implanting Li ion diffusion LiTFSI LiBF4 Artificial Mobility

Gastric cancer occurring in a patient with Plummer-Vinson syndrome: A case report

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World Journal of Gastroenterology 2005年第44期11卷 7048-7050页

作者： Ki-han kim Min-Chan kim Ghap-Joong Jung Department of Surgery

Plummer-Vinson syndrome (sideropenic dysphagia) is characterized by dysphagia due to an upper esophageal or hypopharyngeal web in patients with chronic iron deficiency anemia. The main cause of dysphagia is the presence of the web in the cervical esophagus,and abnormal motility of the pharynx or esophagus is also found to play a significant role in this *** syndrome is thought to be precancerous because squamous cell carcinoma of hypopharynx, oral cavity or esophagus takes place in 10% of those patients suffering from this malady, but it is even more unusual that Plummer-Vinson syndrome should be accompanied by gastric cancer. We have reported here a case of a43-year-old woman with Plummer-Vinson syndrome who developed stomach cancer and recovered after a radical total gastrectomy with D2 nodal dissection.

关键词： Plummer-Vinson syndrome Gastric cancer Esophageal web

Facile synthesis of graphitic carbon-nitride supported antimony-doped tin oxide nanocomposite and its application for the adsorption of volatile organic compounds

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Journal of Environmental Sciences 2019年第5期31卷 35-42页

作者： Devi Prashad Ojha Jun Hee Song han Joo kim Department of Convergence Technology Engineering Chonbuk National University Eco-friendly Machine Parts Design Center Chonbuk National University

Antimony-doped tin oxide(ATO) nanoparticles with an average size of ～ 6 nm were prepared by co-precipitation and subsequent heat treatment. Graphitic carbon nitride(g-CN)/ATO hybrid nanocomposite was designed by the combination of thermally synthesized g-CN and ATO nanoparticles by ultrasonication. The materials were characterized using N2 adsorption/desorption(BET), X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEM) and Fourier transform infrared spectroscopy(FTIR). A mixture of five volatile organic compounds(VOCs, chloroform, benzene, toluene, xylene and styrene) was used to compare the adsorption capacity of the samples. The adsorption capacity of ATO nanoparticles was improved by the addition of g-CN. Experimental data showed that, among the five VOCs,chloroform was the least adsorbed, regardless of the samples. The g-CN/ATO showed nearly three times greater adsorption capacity for the VOC mixture than pure ATO. The unchanged efficiency of VOC adsorption during cyclic use demonstrated the completely reversible adsorption and desorption behavior of the nanocomposite at room conditions. This economically and environmentally friendly material can be a practical solution for outdoor and indoor VOC removal.

关键词： Antimony-doped tin oxide(ATO) Graphitic carbon nitride(g-CN) Volatile organic compounds(VOC) Adsorption

Bile-derived circulating extracellular mi R-30d-5p and mi R-92a-3p as potential biomarkers for cholangiocarcinoma

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Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 41-50页

作者： Hye Sook han Mi Jin kim Joung-Ho han Jieun Yun Hee Kyung kim Yaewon Yang Ki Bae kim Seon Mee Park Department of Internal Medicine Chungbuk National University HospitalCheongju 28644Korea Departments of Internal Medicine Chungbuk National University College of MedicineCheongju 28644Korea Department of Pharmaceutical Engineering College of Science EngineeringCheongju UniversityCheongju 28644Korea

Background: Cholangiocarcinoma (CCA) is from cholangiocytes, and therefore bile is a potentially rich source of biomarkers for CCA. The aim of the study was to identify and validate microRNAs (miRNAs) in bile samples that are differentially expressed between benign biliary disease (BBD) and CCA. Methods: Bile samples from 106 patients with obstructive biliary disease were allocated consecutively to a discovery set (10 patients with BBD and 11 with CCA) and then a validation set (48 patients with BBD and 37 with CCA). An miRNA microarray platform was used to screen 1209 miRNAs in the discovery set. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to validate the pro ling results in the discovery and validation sets. In addition, the levels of carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) were determined from patient serum samples. Results: Microarray pro ling showed that miR-30d-5p and miR-92a-3p were signi cantly upregulated in bile from the CCA group compared with those from the BBD group. qRT-PCR results indicated that the expression levels of miR-30d-5p and of miR-92a-3p were signi cantly upregulated in the CCA group compared to the BBD group, validating the miRNA microarray results. Pathway analysis suggested that putative target genes of miR-30d-5p and of miR-92a-3p were involved in CCA-associated signalling path- ways, such as Hippo, Wnt, p53, MAPK, and EGFR. Receiver operating curve analysis revealed that the areas under the curve for bile miR-30d-5p, miR-92a-3p, serum CA19-9, and CEA were 0.730, 0.652, 0.675, and 0.603, respectively, and bile miR-30d-5p showed the best diagnostic performance with a sensitivity of 81.1% and a speci city of 60.5%. Conclusions: The levels of extracellular miR-30d-5p and miR-92a-3p in bile were signi cantly higher in patients with CCA than those in patients with BBD. Bile-derived circulating extracellular miR-30d-5p and miR-92a-3p are potential biomarkers for discr

关键词： Bile Biomarkers Cholangiocarcinoma MicroRNA

Development of Cloud Based Air Pollution Information System Using Visualization

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Computers, Materials & Continua 2019年第6期59卷 697-711页

作者： SangWook han JungYeon Seo Dae-Young kim SeokHoon kim HwaMin Lee Deptartment of Computer Science and Engineering Soonchungyang UniversityAsan31538Korea School of Information Technology Engineering Daegu Catholic UniversityGyeongsan38430Korea Department of Computer Software and Engineering Soonchungyang UniversityAsan31538Korea

Air pollution caused by fine dust is a big problem all over the world and fine dust has a fatal impact on human *** there are too few fine dust measuring stations and the installation cost of fine dust measuring station is very *** this paper,we propose Cloud-based air pollution information system using *** measure fine dust,we have developed an inexpensive measuring device and studied the technique to accurately measure the concentration of fine dust at the user’s *** we have developed the smartphone application to provide air pollution *** our system,we provide collected data based analytical results through effective data *** system provides information on fine dust value and action tips through the air pollution information *** it supports visualization on the map using the statistical program *** user can check the fine dust statistics map and cope with fine dust accordingly.

关键词： Air pollution visualization R big data cloud clusters