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中国有色金属学会会刊：英文版 2012年第S3期22卷 596-604页

作者： Dong-Yoon kim young-Whan PARK Department of Mechanical Engineering Pukyong National University

Aluminum welding using a hybrid system with a laser and scanner welding head was performed under various welding conditions to verify the feasibility of applying an aluminum alloy to a car *** experimental material was 5J32 aluminum alloy,and the laser power,welding speed,and laser incidence angle were used as the control *** weld bead shape and the tensile shear strength were evaluated in order to understand the aluminum lap joint weld *** of variance (ANOVA) was conducted to identify the effect of the process variables on the tensile shear *** strength estimation models using three different regression models were also *** input variables were the laser power,welding speed,and laser incidence angle,and the output was the tensile shear *** the models,the second-order polynomial estimation model had the best estimation performance,and the average error rate of this model was 0.058.

关键词： laser welding scanner remote welding 5J32 aluminum alloy regression model

Effects of foundation damage and water-level change on vibration modal parameters of gravity-type caisson structure

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Science China(Technological Sciences) 2015年第2期58卷 316-329页

作者： LEE So-young kim Jeong-Tae Department of Ocean Engineering Pukyong National University

In this paper,the effects of foundation damage and water-level change on vibration characteristics of gravity-type caisson structure are examined by analyzing modal parameters extracted from output-only *** achieve the objective,the following approaches are ***,vibration response analysis methods are selected to estimate power spectral density and modal parameters such as natural frequency,damping ratio and mode shape of a lab-scale caisson structural ***,vibration tests on the lab-scale caisson system are performed under a series of test scenarios which include three water-level changes and three damage ***,experimental modal parameters corresponding to the damaging cases as well as the water level cases are extracted by frequency domain decomposition method and stochastic subspace identification ***,the effects of the water-level variation and foundation damage on the extracted modal parameters are examined to assess the feasibility of the vibration-based damage detection in gravity-type caisson structures under water-level uncertainty.

关键词： caisson structure gravity-type structure modal parameter effect of water-level foundation damage

Effect of Plastic Anisotropy on the Formability of Aluminum 6016-T4 Sheet Material

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 625-631页

作者： young-Suk kim Seung-Han YANG kyungpook national university Daegu 41566Republic of Korea

Sheet metal formed of lightweight materials such as aluminum sheeting has received great attention related to the reduction of vehicle emissions. This paper evaluates the anisotropic yield locus using Kuwabara＇s biaxial tensile tester and stretches formability using Hecker＇s hemispheri- cal punch stretching test for aluminum 6016-T4 sheet material. The anisotropic yield locus of the A16016-T4 sheet measured is fitted well by the modified Drucker yield func- tion. Moreover the best fitting to the experimental stress- strain curve from the tensile test was obtained by taking an appropriate hardening model. Analytical study to predict the stretch formability by using Hora＇s Modified Maximum Force Criterion （MMFC） was performed. The predicted forming limit curves （FLC） based on various yield functions were compared with the experiments and discussed.

关键词： Anisotropic yield function AluminumA16016-T4 Biaxial tensile test Forming limit curve

cAMP/PKA pathway and mitochondrial protection in oxidative stress-induced optic nerve head astrocytes

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Neural Regeneration Research 2021年第1期16卷 108-109页

作者： Keun-young kim Won-Kyu Ju National Center for Microscopy and Imaging Research and Department of Neurosciences University of California San DiegoLa JollaCAUSA Hamilton Glaucoma Center and Shiley Eye Institute The Viterbi Family Department of OphthalmologyUniversity of California San DiegoLa JollaCAUSA

Oxidative stress and cyclic adenosine 3′,5′-monophosphate(cAMP)/protein kinase A(PKA)pathway in the optic nerve head astrocytes:Glaucoma is a leading cause of blindness worldwide in individuals 60 years of age and *** the widely appreciated disease relevance of structural and functional abnormalities of astrocyte in the optic nerve head(ONH)that is associated with retinal ganglion cell(RGC)axon degeneration,the molecular mechanisms underlying astrocyte dysfunction in glaucomatous ONH degeneration are poorly *** stress is strongly linked to glaucoma pathogenesis,and astrocytes are the responsible cell type that is mostly related to oxidative stress and glaucomatous ONH degeneration.

关键词： oxidative stress degeneration

Liquid crystal between two distributed Bragg reflectors enables multispectral small-pitch spatial light modulator

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Light(Science & Applications) 2022年第8期11卷 1643-1645页

作者： Junghyun Park Kanghee Won young kim Advanced Sensor Lab Device Research CenterSamsung Advanced Institute of TechnologySuwonRepublic of Korea

The ability of controlling the phase of light at the subwavelength scale can be a game-changer due to its extraordinally wide angle-range in the wavefront shaping. By combining two conventional material and configurat... 详细信息

关键词： crystal enable light

Separation of primary solid phases from Al-Si alloy melts

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China Foundry 2014年第4期11卷 382-395页

作者： Ki young kim School of Energy Materials and Chemical EngineeringKorea University of Technology and EducationChungnam 330-708Korea

The iron-rich solids formed during solidification of Al-Si alloys which are known to be detrimental to the mechanical,physical and chemical properties of the alloys should be *** the other hand,Al-Si hypereutectic alloys are used to extract the pure primary silicon which is suitable for photovoltaic cells in the solvent refining *** of the important issues in iron removal and in solvent refining is the effective separation of the crystallized solids from the Al-Si alloy *** paper describes the separation methods of the primary solids from Al-Si alloy melts such as sedimentation,draining,filtration,electromagnetic separation and centrifugal separation,focused on the iron removal and on the separation of silicon in the solvent refining process.

关键词： separation Al-Si alloys primary solids iron removal silicon extraction

Mechanical properties of high-strength concrete subjected to high temperature by stressed test

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中国有色金属学会会刊：英文版 2009年第B9期19卷 128-133页

作者： Gyu-Yong kim young-Sun kim Tae-Gyu LEE Division of Architecture Engineering Chun gnam National University

Recently, the effects of high temperature on compressive strength and elastic modulus of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures ranging from 20 ℃ to 700 ℃ on the material mechanical properties of high-strength concrete of 40, 60 and 80 MPa grade. During the strength test, the specimens are subjected to a 25% of ultimate compressive strength at room temperature and sustained during heating, and when the target temperature is reached, the specimens are loaded to failure. The tests were conducted at various temperatures (20-700 ℃) for concretes made with W/B ratios of 46%, 32% and 25%, respectively. The results show that the relative values of compressive strength and elastic modulus decrease with increasing compressive strength grade of specimen.

关键词：高强混凝土高温作用力学性能测试抗压强度温度升高弹性模量强度试验

Data Aggregation-based Transmission Method in Ultra-Dense Wireless Networks

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Intelligent Automation & Soft Computing 2023年第1期35卷 727-737页

作者： Dae-young kim Seokhoon kim Department of Computer Software Engineering Soonchunhyang UniversityAsan31538Korea

As the Internet of Things(IoT)advances,machine-type devices are densely deployed and massive networks such as ultra-dense networks(UDNs)are *** devices attend to the network to transmit data using machine-type communication(MTC),whereby numerous,various are *** devices generally have resource constraints and use wireless *** this kind of network,data aggregation is a key function to provide transmission *** can reduce the number of transmitted data in the network,and this leads to energy saving and reducing transmission *** order to effectively operate data aggregation in UDNs,it is important to select an aggregation point *** total number of transmitted data may vary,depending on the aggregation point to which the data are ***,in this paper,we propose a novel data aggregation scheme to select the appropriate aggregation point and describe the data transmission method applying the proposed aggregation *** addition,we evaluate the proposed scheme with extensive computer *** performances in the proposed scheme are achieved compared to the conventional approach.

关键词： Data aggregation data transmission ultra-dense network machine-type communication Internet of Things

High-temperature Oxidation Behavior of Zircaloy-4 and Zirlo in Steam Ambient

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Journal of Materials Science & Technology 2010年第9期26卷 827-832页

作者： Hyung Hoon kim Jun Ho kim Jin young Moon Ho Seong Lee Jeong Joo kim young Suck Chai School of Materials Science and Engineering Kyungpook National University School of Mechanical Engineering Yeungnam University214-1 Dae-dongGyeongsan-si

The oxidation characteristics for Zircaloy-4 and Zirlo in the temperature range of 700-1200°C under steam supply condition were investigated by using a modified thermo-gravimetric *** specimens were oxidized for 3600 s at each temperature and then quenched in a *** oxidation rate constants were measured from the weight gains to evaluate the oxidation behavior in Zircaloy-4 and *** weight gain rates of Zirlo were lower than those of Zircaloy-4,leading to the low rate *** different oxidation behaviors between both cladding materials were considered to be due to the difference in their chemical compositions.

关键词： Zircaloy-4 Zirlo Oxidation

Comparison of mesophilic and thermophilic anaerobic digestions of thermal hydrolysis pretreated swine manure: Process performance,microbial communities and energy balance

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Journal of Environmental Sciences 2023年第4期126卷 222-233页

作者： Xiaohui Liu Changmin Lee Jae young kim Department of Civil and Environmental Engineering Seoul National UniversitySeoul 08826Korea

Anaerobic digestion (AD) of swine manure (SM) commonly shows low biogas output and unsatisfactory economic performance. In this study, thermophilic AD (TAD, 50±1℃) was combined with thermal hydrolysis pretreatment (THP, 170℃/10 bar), to investigate its potential for maximizing biogas yield, securing successful digestion and microbial diversity, as well as improving energy balance. Four lab-scale continuously stirred tank reactors were operated for 300 days and compared with each other, i.e., reactor 1 (raw SM fed in mesophilic AD:RSM-MAD), reactor 2 (THP-treated SM fed in MAD:TSM-MAD), reactor 3 (RSM-TAD),and reactor 4 (TSM-TAD). The results showed that THP was efficient to increase methane production of SM, TSM-TAD mode led to the highest methane yield (129.8±40.5 mL-CH_(4)/gVS/day) among the tests (p 700 mg/L) or volatile fatty acids (> 6000 mg/L) accumulation compared with MAD in start-up phase, TSM-TAD treatment mode behaved a sustainable digestion process in a long-term operation. For TSM-TAD scenario, higher Shannon–Weaver (3.873) and lower Simpson index (0.061) indicated this mode ensured and enlarged the diversity of bacteria communities. Phylum Bathyarchaeota was dominant (59.3%-90.0%) in archaea community,followed by Euryarchaeota in the four reactors. RSM-MAD treatment mode achieved the highest energy output (4.65 GJ/day), TSM-TAD was less effective (-17.38 GJ/day) due to increased energy demands. Thus improving the energetic efficiency of THP units is recommended for the development of TSM-TAD treatment mode.

关键词： Thermal hydrolysis pretreatment Digestion temperature Process performances Microbial communities Energy balance