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Journal of Materials Science & Technology 2022年第3期98卷 248-257页

作者： Dong Hwi kim Jee-Hyun Kang Hojun Gwon Joo Hyun Ryu Sung-joon kim Graduate Institute for Ferrous Technology Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Materials Science and Engineering Institute of Materials TechnologyYeungnam UniversityGyeongsan 38541Republic of Korea POSCO Technical Research Laboratories POSCOGwangyang 57807Republic of Korea

Silicon is an essential alloying element in quenching and partitioning(Q&P)steels,because it is known to suppress carbide precipitation during partitioning step and promote carbon partitioning to stabilize *** 2 wt%Si was added to 10Mn-2Al-0.2C steel,the size and fraction of the carbides formed during partitioning became smaller than in the Si-free ***,the suppression of carbide formation promoted C partitioning into austenite as ***,austenite stability was always lower with Si under the equivalent partitioning condition because Si effectively decreased the stacking fault energy of *** partitioning progressed,the both yield and tensile strengths of the Si-added steel exceeded that of the Si-free steel with the similar ductility *** was because Si was an effective solid solution strengthener,and the austenite in the Si-added steel exhibited the appropriate stability to gradually transform into martensite throughout the *** resulting strengthening effect compensated for the softening caused by martensite ***,strain hardening rate decreased continuously throughout deformation,which resulted in high tensile strength and ductility.

关键词： Steels Q&P steel Silicon Austenite stability Tensile deformation Stacking fault energy Medium Mn steel

Time-course pattern of neuronal loss and gliosis in gerbil hippocampi following mild, severe, or lethal transient global cerebral ischemia

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Neural Regeneration Research 2019年第8期14卷 1394-1403页

作者： Tae-Kyeong Lee Hyunjung kim Minah Song Jae-Chul Lee joon Ha Park Ji Hyeon Ahn Go Eun Yang Hyeyoung kim Taek Geun Ohk myoung Cheol Shin Jun Hwi Cho Moo-Ho Won Depart merit of Neurobiology School of Medici ne Kangw on National University Chuncheon Gangwon Republic of Korea Department of Biomedical Science and Research Institute for Bioscience and Biotechnology Hallym University Chuncheon Gangwon Republic of Korea Department of Radiology Kangwon National University Hospital Chuncheon Gangxvon Republic of Korea Department of Anesthesiology and Pain Medicine Chungju Hospital Konkuk University School of Medicine Chungju Chungcheongbuk Republic of Korea Department of Emergency Medicine School of Medicine Kangwon National University Chuncheon Gangwon Republic of Korea

Transient ischemia in the whole brain leads to neuronal loss/death in vulnerable brain regions. The striatum, neocortex and hippocampus selectively loose specific neurons after transient ischemia. Just 5 minutes of transient ischemia can cause pyramidal neuronal death in the hippocampal cornu ammonis (CA) 1 field at 4 days after transient ischemia. In this study, we investigated the effects of 5-minute (mild), 15-minute (severe), and 20-minute (lethal) transient ischemia by bilateral common carotid artery occlusion (BCCAO) on behavioral change and neuronal death and gliosis (astrocytosis and microgliosis) in gerbil hippocampal subregions (CA1-3 region and dentate gyrus). We performed spontaneous motor activity test to evaluate gerbil locomotor activity, cresyl violet staining to detect cellular distribution, neuronal nuclei immunohistochemistry to detect neuronal distribution, and Fluoro-Jade B histofluorescence to evaluate neuronal death. We also conducted immunohistochemical staining for glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 (Ibal) to evaluate astrocytosis and microgliosis, respectively. Animals subjected to 20-minute BCCAO died in at least 2 days. BCCAO for 15 minutes led to pyramidal cell death in hippocampal CA1-3 region 2 days later and granule cell death in hippocampal de匚tate gyrus 5 days later. Similar results were not found in animals subjected to 5-minute BCCAO. Gliosis was much more rapidly and severely progressed in animals subjected to 15-minute BCCAO than in those subjected to 5- minute BCCAO. Our results indicate that neuronal loss in the hippocampal formation following transient ischemia is significantly different according to regions and severity of transient ischemia. The experimental protocol was approved by Institutional Animal Care and Use Committee (AICUC) of Kangwon National University (approval No. KW-180124-1) on May 22, 2018.

关键词： transient global brain ischemia delayed neuronal death glial activation ischemic duration hippocampus spontaneous motor activity Mongolian gerbil histology neural regeneration

Experimental Investigation of Flexible Hawkmoth-like Wings on the Wing-wake Interaction in Hovering Flight

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Journal of Bionic Engineering 2018年第1期15卷 139-153页

作者： YeongGyun Ryu Jo Won Chang joon Chung Dong-Ha kim Department of Aerospace Engineering Ryerson University Toronto Ontario M5B 2K3 Canada Department of Aeronautical Science and Flight Operation Korea Aerospace University 76 Hanggongdaehak-ro Deogyang-gu Goyang-si Gyeonggi-do 10540 Republic of Korea Aerodynamics Group Korean Air R&D Center Daejeon Metropolitan City 34054 Republic of Korea

To study wing-wake interaction for various wing flexibilities, force measurements and digital particle image velocimetry were carried out on flapping hawkmoth-like wings in a water tank. Wing thickness was employed as a design variable for the wing flexi- bility distributions. Abrupt flap-down and phase delay in flexible wings influenced the behaviors of the Leading-Edge Vortex （LEV） and Trailing-Edge Vortex （TEV）, generated by the previous stroke. While the rigid wing exhibited a detached LEV at the end of the stroke, wing with specific flexibilities obtained attached LEVs. The attached LEVs induced a relatively rapid flow toward the wing surface as a result of encountering the TEV, and the flow caused a higher lift peak. On the other hand, the wings with larger wing deformations generated distinctive changes in LEV and TEV behaviors. The flap-down helped the TEV form closer to the wing surface, and it thus caused a downwash rather than wing-wake interaction. Furthermore, the most flexible wing had a newly-formed pair of LEVs above the wing during the wing reversal, thereby being not able to generate the wing-wake interaction. These results help to understand the different vortex structures generated by flexible wings during the wing reversal and the corresponding effects of wing-wake interaction.

关键词： hovering flight flexible hawkmoth wings wing-wake interaction Digital Particle Image Velocimetry (DPIV)

Hopping-Aware Cluster Header Capability for Sensor Relocation in Mobile IoT Networks

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Intelligent Automation & Soft Computing 2023年第5期36卷 1613-1625页

作者： Moonseong kim Jaeyoung Park Young-joon kim Woochan Lee Department of IT Convergence Software Seoul Theological UniversityBucheon14754Korea Department of Computer Engineering Hongik UniversitySeoul04066Korea Department of Electronic Engineering Gachon UniversitySeongnam13120Korea Department of Electrical Engineering Incheon National UniversityIncheon22012Korea

Mobile sensor nodes such as hopping sensors are of critical importance in data ***,the occurrence of sensing holes is unavoidable due to the energy limitation of the ***,it is evident that the relocation of mobile sensors is the most desirable method to recover the sensing *** previous research conducted by the authors so far demonstrated the most realistic hopping sensor relocation scheme,which is suitable for the distributed *** previous studies,the cluster header plays an essential role in detecting the sensing hole and requesting the neighboring cluster to recover the sensing hole that occurred in the sensor ***,the limitations of the cluster header in the previously proposed relocation protocol are not fully *** the cluster header jumps more frequently than non-header nodes,its energy con-sumption is relatively high compared to other ***,it is most likely to lead to header node failure and can lead to data loss on the *** this paper,the jumping ability and energy consumption of the cluster header are seriously *** ability to replace cluster headers in case of failure is also *** results show that the data collection time can be further increased,which demonstrates the validity of the proposed algorithms.

关键词： Hopping sensor mobileinternetofthings relocationprotocol header node numericalsimulation

Severe alcoholic hepatitis-current concepts, diagnosis and treatment options

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World Journal of Hepatology 2014年第10期6卷 688-695页

作者： Won kim Dong joon kim Department of Internal Medicine Seoul MetropolitanGovernment Seoul National University Boramae Medical Center Department of Internal Medicine Hallym Uni-versity College of Medicine

Alcoholic hepatitis(AH) is an acute hepatic manifesta-tion occurring from heavy alcohol ingestion. Alcoholic steatohepatitis(ASH) is histologically characterized by steatosis, inflammation, and fibrosis in the liver. Despite the wide range of severity at presentation, those with severe ASH(Maddrey's discriminant function ≥ 32) typically present with fever, jaundice, and abdominal tenderness. Alcohol abstinence is the cornerstone of therapy for AH and, in the milder forms, is sufficient for clinical recovery. Severe ASH may progress to multi-or-gan failure including acute kidney injury and infection. Thus, infection and renal failure have a major impact on survival and should be closely monitored in patients with severe ASH. Patients with severe ASH have a re-ported short-term mortality of up to 40%-50%. Severe ASH at risk of early death should be identified by one of the available prognostic scoring systems before consid-ering specific therapies. Corticosteroids are the main-stay of treatment for severe ASH. When corticosteroids are contraindicated, pentoxifylline may be alternatively used. Responsiveness to steroids should be assessed at day 7 and stopping rules based on Lille score should come into action. Strategically, future studies for pa-tients with severe ASH should focus on suppressing inflammation based on cytokine profiles, balancing he-patocellular death and regeneration, limiting activation of the innate immune response, and maintaining gut mucosal integrity.

关键词： Alcoholic steatohepatitis Infection Renal failure Corticosteroids Pentoxifylline

Stud welding for fixation of cryogenic insulation of membrane tanks in LNG ship building

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中国有色金属学会会刊：英文版 2009年第B9期19卷 271-275页

作者： Jeong-Soo LEE Young-Soo RYU Nam-In kim Bong-joon kim Yoo-Kyung kim Myung-Hyun kim Hanjin Heavy Industries & Construction Co. Ltd Department of Naval Architecture and Ocean Engineering Pusan National University

The support plates including all of the inner hulls such as E grade steel, weld seams and SUS304L were considered to establish the optimal stud welding condition in LNG ship building. The stainless steel plate was especially applied to the bracket on the liquid dome. The polished and etched surfaces of the welded stud and support plate were examined if the bead was properly formed. With the micrographic examination, the fusion boundary of metal weld zone formed by stud welding was analyzed to optimize the welding parameters. And also the analysis of the unacceptable welding faults such as cold and hot weld were performed. The mechanical tests such as tensile tests and bending tests were carried out to reveal any abnormal variation in the relationship of process parameters and the strength.

关键词：螺柱焊接 LNG船绝缘膜优化工艺参数低温坦克不锈钢板最佳条件

Nanomolar concentration of alpha-synuclein enhances dopaminergic neuronal survival via Akt pathway

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Neural Regeneration Research 2013年第35期8卷 3269-3274页

作者： Ji-Young kim Beom Seok Jeon Han-joon kim Tae-Beom Ahn Department of Neurology Inje University Seoul Paik Hospital Department of Neurology College of Medicine Seoul National University Hospital Department of Neurology Kyung Hee University Medical Center

Although alpha-synuclein is generally thought to have a pathological role in Parkinson＇s disease, accumulative evidence exists that alpha-synuclein has a neuroprotective effect. The aim of this study was to evaluate the effect of extracellular alpha-synuclein on dopaminergic cell survival. We assessed cell viability using the 3-（4,5-dimethyt-thiazol-2-yt）-2,5-diphenyltertazolium bromide （MTT） assay both in undifferentiated SH-SY5Y （SHSY） cells and neuronally-differentiated SH-SY5Y （ndSHSY） cells after 24 hour treatment with monomeric alpha-synuclein at various concentrations （0 [control], 50, 100 nmol/L, 1 IJmol/L）. To determine whether cell viability assessed by MTT assay was affected by cell proliferation, 5-bromo-2＇-deoxyuridine （BrdU） incorporation assay was per- formed. Level of both Akt and phosphorylated Akt was measured using western blot method in ndSHSY cells with or without 24 hour alpha-synuclein treatment. Cell viability was increased in ndSHSY cells at the nanomolar concentration of alpha-synuclein, but not in SHSY cells. Proportion of BrdU-positive ndSHSY cells was decreased in alpha-synuclein-treated group compared with control group. Level of phosphorylated Akt in alpha-synuclein-treated group was higher compared with the control group. Our study shows that extracellular alpha-synuclein at nanomolar concentra- tion benefits dopaminergic cell survival via Akt pathway.

关键词： neural regeneration alpha-synuclein neuronal survival nanomolar extracellular phosphorylatedAkt SH-SY5Y cell neuronal differentiation proliferation dopaminergic 5-bromo-2'-deoxyuridine grants-supported paper neuroregeneration

GRU-based Buzzer Ensemble for Abnormal Detection in Industrial Control Systems

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Computers, Materials & Continua 2023年第1期74卷 1749-1763页

作者： Hyo-Seok kim Chang-Gyoon Lim Sang-joon Lee Yong-Min kim Interdisciplinary Program of Information Security Chonnam National UniversityGwangju61186Korea Major in Computer Engineering Chonnam National UniversityYeosu59626Korea School of Business Administration Chonnam National UniversityGwangju61186Korea Department of Electronic Commerce Chonnam National UniversityYeosu59626Korea

Recently,Industrial Control Systems(ICSs)have been changing from a closed environment to an open environment because of the expansion of digital transformation,smart factories,and Industrial Internet of Things(IIoT).Since security accidents that occur in ICSs can cause national confusion and human casualties,research on detecting abnormalities by using normal operation data learning is being actively *** single technique proposed by existing studies does not detect abnormalities well or provide satisfactory *** this paper,we propose a GRU-based Buzzer Ensemble for AbnormalDetection(GBE-AD)model for detecting anomalies in industrial control systems to ensure rapid response and process *** newly proposed ensemble model of the buzzer method resolves False Negatives(FNs)by complementing the limited range that can be detected in a single model because of the internal models composing *** the internal models remain suppressed for False Positives(FPs),GBE-AD provides better *** addition,we generated mean prediction error data in GBE-AD and inferred abnormal processes using soft and hard *** confirmed that the detection model’s Time-series Aware Precision(TaP)suppressed FPs at 97.67%.The final performance was 94.04%in an experiment using anHIL-basedAugmented ICS(HAI)Security Dataset(ver.21.03)among public datasets.

关键词： Industrial control system abnormal detection ensemble learning HAI dataset

Study on frictional behavior of carbon nanotube thin films with respect to surface condition

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Friction 2018年第4期6卷 432-442页

作者： Youn-Hoo HWANG Byung-Soo MYUNG Hyun-joon kim Department of Precision Mechanical Engineering Kyungpook National University

In this work, tribological characteristics of thin films composed of entangled carbon nanotubes(CNTs) were investigated. The surface roughness of CNT thin films fabricated via a dip‐coating process was controlled by squeezing during the process with an applied normal force ranging from 0 to 5 kgf. Raman spectra and scanning electron microscopy(SEM) images of the thin films were obtained to estimate the influence of the squeezing process on the crystallinity of the CNTs. The analysis revealed that squeezing could reduce surface roughness, while preserving the crystallinity of the CNTs. Moreover, the surface energy of the cover glass used to press the CNT thin film was found to be the critical factor controlling surface roughness. A micro‐tribometer and macro‐tribometer were used to assess the tribological characteristics of the CNT thin film. The results of the tribotest exhibited a correlation between the friction coefficient and surface roughness. Dramatic changes in friction coefficient could be observed in the micro‐tribotest, while changes in friction coefficient in the macro‐tribotest were not significant.

关键词： carbon nanotubes friction surface roughness surface energy squeezing process UV irradiation

A metallic anti-biofouling surface with a hierarchical topography containing nanostructures on curved micro-riblets

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Microsystems & Nanoengineering 2022年第1期8卷 83-96页

作者： Taekyung kim Sunmok Kwon Jeehyeon Lee joon Sang Lee Shinill Kang National Center for Optically-assisted high precision Mechanical Systems Yonsei UniversitySeoul 03722Korea School of Mechanical Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Korea

Metallic surface finishes have been used in the anti-biofouling,but it is very difficult to produce surfaces with hierarchically ordered *** the present study,anti-biofouling metallic surfaces with nanostructures superimposed on curved micro-riblets were produced via top-down *** to the attachment theory,these surfaces feature few attachment points for organisms,the nanostructures prevent the attachment of bacteria and algal zoospores,while the micro-riblets prohibit the settlement of *** oxidation was performed to induce *** forms a hydration layer on the surface,which physically blocks foulant adsorption along with the anti-biofouling *** characterized the surfaces via scanning electron and atomic force microscopy,contact-angle measurement,and wear-resistance *** contact angle of the hierarchical structures was less than 1°.Laboratory settlement assays verified that bacterial attachment was dramatically reduced by the nanostructures and/or the hydration layer,attributable to *** micro-riblets prohibited the settlement of *** 77 days of static immersion in the sea during summer,the metallic surface showed significantly less biofouling compared to a surface painted with an anticorrosive coating.

关键词： Anti-biofouling Superhydrophilic Hierarchical topography Metallic engineered surface Nanoimprinting,static immersion test,field trials