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Nano Research 2018年第5期11卷 2366-2378页

作者： You Jin Min kyeong-hee kang Dae-Eun Kim Department of Mechanical Engineering Yonsei University 50 Yonsei-ro Seodaemun-gu Seoul 03722 Republic of Korea

The benefits of reinforcing polyimide （PI） films with boron nitride （BN） particles and boron nitride nanosheets （BNNSs） were assessed with the aim of enhancing their thermal, optical, and mechanical properties for flexible device applications. BNNSs were prepared from BN particles using a liquid-phase exfoliation method assisted by an ultrasonic probe-type sonicator and centrifugator. PI-based composite films blended with BNNSs and BN particles were fabricated at various concentrations via mechanical stirring and spin coating. The transparency of the PI/BNNS composite films remained almost the same as that of pure PI films up to 3 wt.% whereas the transparency of the PI/BN composite films decreased with increasing concentration of the BN fillers at 550 nm. The thermal stability improved significantly with increasing concentrations of both BN and BNNS relative to that of pure PI films. The temperature for 5% weight loss of the PI/BNNS composite film was higher than that of the PI/BN composite film at the same filler concentration. The composite films with 2 wt.% BN or BNNS showed the lowest wear rate, and the PI/BNNS composite films showed more stable frictional behavior compared to the PI/BN composite films. In addition, bending tests showed that the PI/BNNS composite films exhibited excellent flexibility compared to the PI/BN composite films. Overall, the results indicate that the BNNS can be effectively used as a filler that can enhance the thermal and mechanical properties of polymer materials for flexible device applications.

关键词： polyimide (PI) boron nitride (BN) transparency thermal properties flexibility tribology

Optimization of an Artificial Intelligence Database and Camera Installation for Recognition of Risky Passenger Behavior in Railway Vehicles

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Computers, Materials & Continua 2025年第1期82卷 1277-1293页

作者： Min-kyeong Kim Yeong Geol Lee Won-hee Park Su-hwan Yun Tae-Soon Kwon Duckhee Lee Railroad Test&Certification Division Korea Railroad Research Institute(KRRI)Cheoldo BangmulgwanroUiwang-si16105Republic of Korea Railroad Safety Division Korea Railroad Research Institute(KRRI)Cheoldo BangmulgwanroUiwang-si16105Republic of Korea

Urban railways are vital means of public transportation in *** than 30%of metropolitan residents use the railways,and this proportion is expected to *** enhance safety,the government has mandated the installation of closed-circuit televisions in all carriages by ***,cameras still monitored *** address this limitation,we developed a dataset of risk factors and a smart detection system that enables an immediate response to any abnormal behavior and intensive monitoring *** created an innovative learning dataset that takes into account seven unique risk factors specific to Korean railway *** data collection was conducted across the Shinbundang Line of the Incheon Transportation Corporation,and the Ui-Shinseol *** observed several behavioral characteristics and assigned unique annotations to *** also considered carriage *** performance was evaluated by camera placement and *** the camera installation plan was *** dataset will find immediate applications in domestic railway *** artificial intelligence algorithms will be verified shortly.

关键词： AI railway vehicle risk factor smart detection AI training data

A palynotaxonomic study of the genus Filipendula (Rosaceae)

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Journal of Systematics and Evolution 2009年第2期47卷 115-122页

作者： Sangtae LEE Meekyung kang kyeong-In HEO Chunghee LEE Department of Biology Sungkyunkwan University Division of Botanical Research Korea National Arboretum

Pollen grains from 15 species(18 taxa) of the genus Filipendula were examined with light and scan-ning electron *** was revealed that the pollen grains are isopolar,tricolporate,with scabrate or scabrate-microechinate *** pollen morphology was compared with the conventional classification sys-tems of the genus by different authors,and supported Shimizu’s system(1961),in which the genus was divided into three *** monotypic *** is characterized by pollen lacking fastigium and thickened costae *** other monotypic *** differs from others by pollen having larger grain,larger pore size,longitudinally elliptic fastigium and thickened costae *** largest *** is distinguished by pollen having rounded or latitudinally elliptic fastigium and thickened costae *** classification was not supported by the pollen morphology due to insufficient variability.

关键词： Filipendula palynology systematics

Wave-Tide-Surge Coupled Simulation for Typhoon Maemi

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China Ocean Engineering 2013年第2期27卷 141-158页

作者： Byung Ho Choi Byung Il Min kyeong Ok Kim Jin hee Yuk Department of Civil and Environmental Engineering Sungkyunkwan University Marine Environments & Conservation Research Division Korea Institute of Ocean Science & Technology Supercomputing Center Korea Institute of Science and Technology Information

The main task of this study focuses on studying the effect of wave-current interaction on currents, storm surge and wind wave as well as effects of current induced wave refraction and current on waves by using numerical models which consider the bottom boundary layer and sea surface roughness parameter for shallow and smooth bed area around Korean Peninsula. The coupled system （unstructured-mesh SWAN wave and ADCIRC） run on the same unstructured mesh. This identical and homogeneous mesh allows the physics of wave-circulation interactions to be correctly resolved in both models. The unstructured mesh can be applied to a large domain allowing all energy from deep to shallow waters to be seamlessly followed. There is no nesting or overlapping of structured wave meshes, and no interpolation is required. In response to typhoon Maemi （2003）, all model components were validated independently, and shown to provide a faithful representation of the system＇s response to this storm. The waves and storm surge were allowed to develop on the continental shelf and interact with the complex nearshore environment. The resulting modeling system can be used extensively for prediction of the typhoon surge. The result show that it is important to incorporate the wave-current interaction effect into coastal area in the wave-tide-surge coupled model. At the same time, it should consider effects of depth-induced wave breaking, wind field, currents and sea surface elevation in prediction of waves. Specially, we found that：（1） wave radiation stress enhanced the current and surge elevation otherwise wave enhanced nonlinear bottom boundary layer decreased that, （2） wind wave was significantly controlled by sea surface roughness thus we cautiously took the experimental expression. The resulting modeling system can be used for hindcasting （prediction） the wave-tide-surge coupled environments at complex coastline, shallow water and fine sediment area like areas around Korean Peninsula.

关键词： typhoon Maemi finite element model tide-surge-wave coupling

Preparation of Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 powders for cathode material in secondary battery by solid-state method

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Rare Metals 2006年第Z2期25卷 184-188页

作者： PARK Sook hee kang Chan Hyoung Department of Advanced Materials Engineering Korea Polytechnic University Shihung Kyonggi-do 429-793 Korea

Employing Li2CO3, NiO, Co3O4, and MnCO3 powders as starting materials, Li[Ni1/3Co1/3Mn1/3]O2 was synthesized by solid-state reaction method. Various grinding aids were applied during milling in order to optimize the synthesis process. After successive heat treatments at 650 and 950 ℃, the prepared powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy, and transmission electron microscopy. The powders prepared by adding salt (NaCl) as grinding aid exhibit a clear R3m layer structure. The powders by other grinding aids like heptane show some impurity peaks in the XRD pattern. The former powders show a uniform particle size distribution of less than 1 μm average size while the latter shows a wide distribution ranging from 1 to 10 μm. Energy dispersive X-ray (EDX) analysiss show that the ratio of Ni, Co, and Mn content in the powder is approximately 1/3, 1/3, and 1/3, respecively. The EDX data indicate no incorporation of sodium or chlorine into the powders. Charge-discharge tests gave an initial discharge capacity of 160 mAh·g-1 for the powders with NaCl addition while 70 mAh·g-1 for the powders with heptane.

关键词： lithium ion battery cathode materials layered structure solid-state method discharge density

Simulation of Storm Surge and Wave Due to Typhoon Isewan(5915)

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China Ocean Engineering 2015年第4期29卷 473-488页

作者： Jin-hee YUK kyeong Ok KIM Han Soo LEE Byung Ho CHOI Disaster Management HPC Technology Research Center Korea Institute of Science and Technology Information Marine Radionuclide Research Center Korea Institute of Ocean Science & Technology Graduate School of Science and Engineering Saitama University Department of Civil and Environmental Engineering Sungkyunkwan University

An integrally coupled wave-tide-surge model was developed and then applied to the simulation of the wave-typhoon surge for the typhoon Isewan （typhoon Vera （5915））, which is the strongest typhoon that has struck Japan and caused incalculable damage. An integrally coupled tide-surge-wave model using identical and homogeneous meshes in an unstructured grid system was used to correctly resolve the physics of wave-circulation interaction in both models. All model components were validated independently. The storm surge and wave properties such as the surge height, the significant wave height, wave period and direction were reproduced reasonably under the meteorological forcing, which was reprocessed to be close to the observations. The resulting modeling system can be used extensively for the prediction of the storm surge and waves and the usual barotropic forecast.

关键词： typhoon Isewan storm surge wave tide coupled wave-tide-surge model

A study on the interference effects for tidal current power rotors

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Science China(Technological Sciences) 2010年第11期53卷 3094-3101页

作者： Chul-hee JO kang-hee LEE Jin-Young YIM Department of Naval Architecture & Ocean Engineering Inha University

Due to global warming, the need to secure an alternative resource has become more important nationally. With the high tidal range of up to 9.7 m on the west coast of Korea, numerous tidal current projects are being planned and constructed. To extract a significant quantity of power, a tidal current farm with a multi-arrangement is necessary in the ocean. The rotor, which initially converts the energy, is a very important component because it affects the efficiency of the entire system, and its performance is determined by various design variables. The power generation is strongly dependent on the size of the rotor and the incoming flow velocity. However, the interactions between devices also contribute significantly to the total power capacity. Therefore, rotor performance considering the interaction problems needs to be investigated for generating maximum power in a specific field. This paper documents a performance study of devices considering the interference between rotating rotors with axial, transverse and diagonal arrangements.

关键词： TCP (tidal current power) renewable energy interference effect rotor CWC (circulation water channel) CFD (computational fluid dynamics)

Insights into the changes in the surface properties of goethite with Ni in the lattice in the presence of salicylhydroxamic acid:Experimental and density functional theory studies

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 665-677页

作者： Levie Mweene Gilsang Hong hee-Eun Jeong hee-won kang Hyunjung Kim Department of Earth Resources and Environmental Engineering Hanyang University222 Wangsimni-roSeongdong-guSeoul 04763Republic of Korea

Comparative experiments and theoretical analysis of the surface chemistry changes of goethite(GT)and goethite containing Ni(GTN)in the lattice in the presence of salicylhydroxamic acid(SA)were *** was revealed that in the presence of 100 g·t^(-1)of SA,the flotation recovery of GTN and GT increased with increasing pH,achieving a maximum recovery of 98.9%for both minerals at p H 8.3 and decreasing beyond that pH,with GTN having a slightly higher recovery than GT,except at pH *** was further confirmed by the higher complexation energies of GTN···SA(-883.87 kJ·mol^(-1))compared with GT···SA(-604.23 kJ·mol^(-1))resulting from covalent,closed-shell,and conventional hydrogen *** higher adsorption of SA onto GTN relative to GT was due to the formation of aπ-hole in GTN,thereby promoting a higher interaction of the collector with the ***,the presence of Ni in the GT lattice improves and decreases the adsorption and desorption of SA onto and from the mineral,respectively,compared with those onto and from GT.

关键词： nickel goethite adsorption salicylhydroxamic acid recovery

Micro-accelerometer Based on Vertically Movable Gate Field Effect Transistor

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Nano-Micro Letters 2015年第3期7卷 282-290页

作者： Heung Seok kang kang-hee Lee Dong-Youk Yang Byoung hee You In-Hyouk Song Korea Atomic Energy Research Institute LOGTECH Co. Ltd 914 Gumgang Hightech Valley 1st Department of Engineering Technology Texas State University601 University Dr. San Marcos TX 78666 USA

A vertically movable gate field effect transistor(VMGFET) is proposed and demonstrated for a microaccelerometer application. The VMGFET using air gap as an insulator layer allows the gate to move on the substrate vertically by external forces. Finite element analysis is used to simulate mechanical behaviors of the designed structure. For the simulation, the ground acceleration spectrum of the 1952 Kern County Earthquake is employed to investigate the structural integrity of the sensor in vibration. Based on the simulation, a prototype VMGFET accelerometer is fabricated from silicon on insulator wafer. According to current–voltage characteristics of the prototype VMGFET, the threshold voltage is measured to be 2.32 V, which determines the effective charge density and the mutual transconductance of1.545910-8C cm-2and 6.59 m A V-1, respectively. The device sensitivity is 9.36–9.42 m V g-1in the low frequency,and the first natural frequency is found to be 1230 Hz. The profile smoothness of the sensed signal is in 3 d B range up to1 k Hz.

关键词： MEMS Micro-accelerometer Suspended gate FET Vertically movable gate FET VMGFET

Recent TCP(Tidal Current Power) projects in Korea

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Science China(Technological Sciences) 2010年第1期53卷 57-61页

作者： Chul hee JO kang hee LEE Yu Ho RHO School of Engineering Inha University253Yonghyun-DongNam-GuIncheon 402-751Republic of Korea Graduate School Department.of Naval Architecture & Ocean EngineeringInha University253Yonghyun-DongNam-GuIncheon 402-751Republic of Korea

Having strong current on the west coast with up to 10 m tidal range in Korea,there are many suitable and applicable locations for TCP(Tidal Current Power) application in *** only the west coast,but also the south west regions having narrow channels between islands creating fast ocean stream are suitable for *** first TCP application in Korea is 1 MW helical VAT(Vertical Axis Turbine) device installed in Wooldolmog area in *** first HAT(Horizontal Axis Turbine) TCP device of 25 KW was developed and installed in cooling water weir of Samchonpo power plant in ***,a 100 kW prototype HAT TCP device is being planned to be installed in Daebang strait in *** big project would be Inchon TCP farm of 200 MW on the west coast in *** consortium of 5 members was formed in April,*** site will be the largest TCP site in the *** paper describes recent TCP projects in Korea with background and environmental conditions of the projects.

关键词： TCP(Tidal Current Power) ocean energy renewable energy clean energy HAT(Horizontal Axis Turbine) VAT(Vertical Axis Turbine)