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Fabrication and Mechanical Properties of Sm2O3 Doped CeO2 Reinforced Ti3AlC2 Nano Composite

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Journal of Rare Earths 2004年第Z2期22卷 85-88页

作者： Jae Ho han Sang Whan Park Young Do kim Division of Materials Science & Engineering Hanyang UniversitySeoul133-791Korea Korea Institute of Science and TechnologyMulti-Functional Ceramics Research CenterSeoul136-791Korea Division of Materials Science & EngineeringHanyang UniversitySeoul133-791Korea

The fabrication process of Sm2O3 doped CeO2 reinforced Ti3AlC2 nano composites including the nano particle dispersion process by a hetero-coagulation process was developed using in-situ synthesis and densification process of Ti3AlC2. The effects of Sm2O2 doped CeO2 nano particles on mechanical properties of Ti3AlC2 were investigated. It was found that the presence of 20SDC nano particles in Ti3AlC2 was very effective to improve the mechanical properties of Ti3AlC2 without spoiling the unique characteristics of Ti3AlC2temary carbide.

关键词： nano ceramic composite Ti3AlC2 CeO2 fabrication rare earths

Electrochemical characteristics of stainless steel using impressed current cathodic protection in seawater

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中国有色金属学会会刊：英文版 2009年第4期19卷 930-934页

作者： Seok-Ki JANG Min-Su han Seong-Jong kim Division of Marine Engineering Mokpo Maritime University

Stainless steels such as STS 304,316 and 630 are frequently used as shaft materials in small fiber reinforced polymer(FRP) fishing *** the shaft material is exposed to a severely corrosive environment such as seawater,it should be protected using appropriate *** impressed current cathodic protection was used to inhibit corrosion in shaft *** anodic polarization,passivity was remarkably more evident in STS 316 stainless steel than in STS 304 and STS *** pitting potentials of STS 304,316,and 630 stainless steels were 0.30,0.323,and 0.260 V,*** concentration polarization due to oxygen reduction and activation polarization due to hydrogen generation were evident in the cathodic polarization trends of all three stainless *** 316 had the lowest current densities in all potential ranges,and STS 630 had the *** analysis showed that STS 316 was the most noble in the *** addition,the corrosion current density was the lowest for STS 316.

关键词：外加电流阴极保护 316不锈钢电化学特性海水腐蚀电流密度材料腐蚀阳极极化 STS

Development of single-action,two-step clinching system using finite element analysis

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中国有色金属学会会刊：英文版 2009年第B9期19卷 266-270页

作者： Seong-Wook LEE Tae-Hyung kim Geun-Jo han Power & Industrial Systems R&D Center Hyosung Corporation Department of Mechanical Engineering Department of Mechanical Engineering Dong-A University

Traditional manufacturing processes for bending and combining the upper and lower heat insulation plates for a car catalytic converter need two kinds of bending dies. This study was carried out to develop a single-action, two-step clinching system for clinching heat insulation plates. To design the operating mechanism for this clinching system, finite element analysis was used to estimate the bending load needed and to predict the bent shape of the heat insulation plate. Then a recovery and cushioning system was designed for the bending die. It is expected that this new process will improve the manufacturing quality of heat insulation plates and will reduce manufacturing cost. And a higher value-added technique for mold and pressing systems was introduced.

关键词：缓冲系统有限元分析开发汽车催化转化器单动模具技术隔热板板弯曲

Unknown Attack Detection:Combining Relabeling and Hybrid Intrusion Detection

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Computers, Materials & Continua 2021年第9期68卷 3289-3303页

作者： Gun-Yoon Shin Dong-Wook kim Sang-Soo kim Myung-Mook han Department of Computer Engineering Gachon UniversitySungnam-si13120Korea Agency for Defense Development Songpa Seoul05661Korea Department of Software Gachon UniversitySungnam-si13120Korea

Detection of unknown attacks like a zero-day attack is a research field that has long been ***,advances in Machine Learning(ML)and Artificial Intelligence(AI)have led to the emergence of many kinds of attack-generation tools developed using these technologies to evade detection *** detection and misuse detection are the most commonly used techniques for detecting intrusion by unknown *** anomaly detection is adequate for detecting unknown attacks,its disadvantage is the possibility of high false *** detection has low false alarms;its limitation is that it can detect only known *** overcome such limitations,many researchers have proposed a hybrid intrusion detection that integrates these two detection *** method can overcome the limitations of conventional methods and works better in detecting unknown ***,this method does not accurately classify attacks like similar to normal or known ***,we proposed a hybrid intrusion detection to detect unknown attacks similar to normal and known *** anomaly detection,the model was designed to perform normal detection using Fuzzy c-means(FCM)and identify attacks hidden in normal predicted data using *** misuse detection,the model was designed to detect previously known attacks using Classification and Regression Trees(CART)and apply Isolation Forest(iForest)to classify unknown attacks hidden in known *** an experiment result,the application of relabeling improved attack detection accuracy in anomaly detection by approximately 11%and enhanced the performance of unknown attack detection in misuse detection by approximately 10%.

关键词： Unknown attack hybrid intrusion detection fuzzy c-means relabeling CART iForest

Science Letters:Human-centered modeling for style-based adaptive games

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 530-534页

作者： Chee-onn WONG Jongin kim Eunjung han Keechul JUNG Human-Centered Interfaces Lab Department of Digital Media Soongsil UniversitySeoul 156743 Korea

This letter proposes a categorization matrix to analyze the playing style of a computer game player for a shooting game genre. Our aim is to use human-centered modeling as a strategy for adaptive games based on entertainment measure to evaluate the playing experience. We utilized a self-organizing map (SOM) to cluster the player's style with the data obtained while playing the game. We further argued that style-based adaptation contributes to higher enjoyment, and this is reflected in our experiment using a supervised multilayered perceptron (MLP) network.

关键词： Player modeling Categorization matrix Adaptive games Human-centered modeling Data clustering

Prediction of high thermoelectric performance in the lowdimensional metal halide Cs_(3)Cu_(2)I_(5)

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npj Computational Materials 2021年第1期7卷 476-481页

作者： Young-Kwang Jung In Taek han Yong Churl kim Aron Walsh Department of Materials Science and Engineering Yonsei UniversitySeoulSouth Korea Samsung Advanced Institute of Technology(SAIT) Samsung Electronics Materials Research ComplexYoungtongSuwonSouth Korea Department of Materials Imperial College LondonLondonUK

Metal halides have emerged as a new generation of semiconductors with applications ranging from solar cells to chemical *** assess the thermoelectric potential of Cs_(3)Cu_(2)I_(5),which has a crystal structure formed of zero-dimensional[Cu_(2)I_(5)]3−anionic clusters that are separated by Cs+counter *** find the compound exhibits the characteristics of a phonon-glass electroncrystal with a large imbalance in the conduction of heat and electrons predicted from first-principles transport *** anharmonic phonon–phonon scattering results in short-lived acoustic vibrations and an ultra-low lattice thermal conductivity(10 cm^(2)V^(−1)s^(−1)).For an n-type crystal at 600 K,a thermoelectric figure-of-merit ZT of 2.6 is found to be accessible,which for a cold source of 300 K corresponds to a thermodynamic heat-to-electricity conversion efficiency of 15%.

关键词： theory phonon crystal

Stability of operation versus temperature of a three-phase clock-driven chaotic circuit

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Chinese Physics B 2013年第12期22卷 152-159页

作者：周继超 Hyunsik Son Namtae kim han Jung Song Department of Nano Systems Engineering Inje University Department of Electronic Engineering Inje University Center for Nano Manufacturing Inje University

We evaluate the influence of temperature on the behavior of a three-phase clock-driven metal–oxide–semiconductor （MOS） chaotic circuit. The chaotic circuit consists of two nonlinear functions, a level shifter, and three sample and hold blocks. It is necessary to analyze a CMOS-based chaotic circuit with respect to variation in temperature for stability because the circuit is sensitive to the behavior of the circuit design parameters. The temperature dependence of the proposed chaotic circuit is investigated via the simulation program with integrated circuit emphasis （SPICE） using 0.6-μm CMOS process technology with a 5-V power supply and a 20-kHz clock frequency. The simulation results demonstrate the effects of temperature on the chaotic dynamics of the proposed chaotic circuit. The time series, frequency spectra, bifurcation phenomena, and Lyapunov exponent results are provided.

关键词： chaotic circuit nonlinear functions temperature effect bifurcation Lyapunov exponent

Fatigue strength evaluation of self-piercing riveted joints of AZ31 Mg alloy and cold-rolled steel sheets

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Journal of Magnesium and Alloys 2020年第1期8卷 241-251页

作者： Se-Hyung Kang Dong-Woon han Ho-Kyung kim Graduate School Seoul National University of Science and TechnologySeoul01811South Korea Department of Mechanical and Automotive Engineering Seoul National University of Science and TechnologySeoul01811 South Korea

The application of magnesium alloys to automobiles is increasing due to their superior specific strength and specific *** this study,an upper sheet of AZ31 magnesium alloy and a lower sheet of cold-rolled steel were joined by self-piercing riveting(SPR),a method commonly used to join automotive panels.A cross-shaped specimen was fabricated with a punching force of 35 kN,which exhibited the best joint strength for the SPR joint specimen *** and fatigue strengths were evaluated using cross-shaped specimens at loading angles of 0°,45°,and 90°.The load amplitude corresponding to the fatigue endurance limit was assumed to be at 106 cycles,and the fatigue ratios(=fatigue endurance limit/static strength)at the loading angles of 0°,45°,and 90°are 22%,13%,and 9%,*** all three loading angle specimens,fatigue cracks initiated at the triple point where the rivet shank,the upper sheet and the lower sheet are in contact with each other,with the cracks propagating through the thickness of the upper sheet and ultimately leading to *** fatigue lifetimes were evaluated through the von-Mises stress,maximum principal stress,and equivalent stress intensity *** was found that the fatigue lifetimes could be evaluated most appropriately through the maximum principal stress.

关键词： Self-piercing riveting Magnesium alloy Fatigue strength Maximum principal stress Fatigue lifetime

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