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Journal of Magnesium and Alloys 2023年第5期11卷 1683-1696页

作者： dong hee lee Gyo Myeong lee Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

The effects of extrusion temperature on the microstructure and tensile properties of extruded AZ61 and AZ91 alloys are investigated by subjecting them to hot extrusion at 300 and 400℃.Although the average grain size of the extruded AZ61 alloy slightly increases from 9.5 to 12.6μm with increasing extrusion temperature,its resultant microstructural variation is *** contrast,the average grain size of the extruded AZ91 alloy significantly increases from 5.7 to 22.5μm with increasing extrusion temperature,and the type of Mg17Al12 precipitates formed in it changes from fine dynamic precipitates with a spherical shape to coarse static precipitates with a lamellar *** the extrusion temperature increases,the tensile yield strength of the extruded AZ61 alloy increases from 183 to 197 MPa while that of the extruded AZ91 alloy decreases from 232 to 224 *** tensile elongations of the extruded AZ61 and AZ91 alloys decrease with increasing extrusion temperature,but the degree of decrease is significant in the latter *** different extrusion temperature dependences of the tensile properties of the extruded AZ61 and AZ91 alloys are discussed in terms of their microstructural characteristics,strengthening mechanisms,and crack initiation sites.

关键词： Mg-Al-Zn alloys Extrusion temperature Precipitation Strengthening mechanism Tensile properties

Suspending Control Scheme of 8/10 Bearingless SRM Based on Adaptive Fuzzy PID Controller

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Chinese Journal of Electrical Engineering 2016年第2期2卷 60-67页

作者： Yingjie He Ying Tang dong-hee lee Jin-Woo Ahn Kyungsung University Busan Korea

As a nonlinear,strong coupling and multi-variable system,the drive performance of bearingless switched reluctance motor(BLSRM)is always limited by its complicated electromagnetic ***,conventional PID methods are used to achieve the basic control requirement in wide industrial applications,however its inherent operating principle limits its use on suspending control of *** this paper,the suspending force system,which is separately controlled from torque system,is built based on an adaptive fuzzy PID controller to limit the rotor eccentric displacement with proper generation of radial *** compared with a system adopted using conventional PID method for suspending force control,the proposed adaptive fuzzy PID method has superior performance in shortening the response time,reducing the maximum eccentric displacement error and higher speed range of operation due to its online self-turning of controller *** in simulation and experimental cases,comparison of results of the above two methods validates the effectiveness of the adaptive fuzzy PID controller for BLSRM drive system.

关键词： BLSRM suspending force control conventional PID controller adaptive fuzzy PID controlle

Variations in microstructure and bending formability of extruded Mg–Al–Zn–Ca–Y–MM alloy with precompression and subsequent annealing treatment conditions

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Journal of Magnesium and Alloys 2022年第9期10卷 2475-2490页

作者： Jong Un lee Sang-Hoon Kim dong hee lee Hyun Ji Kim Young Min Kim Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Agency for Defense Development Daejeon 34186Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

In this study, the bending formability of an extruded Mg–9Al–1Zn–0.3Mn–0.9Ca–0.6Y–0.5 MM(AZXWMM91100, wt%) alloy at room temperature is significantly improved through application of a combined precompression and subsequent annealing(PCA) treatment. As the amount of precompression applied along the extrusion direction(ED)(i.e., the total strain) increases from 4% to 6%, the area fraction of ED-oriented grains of the PCA-treated alloy increases, which consequently causes an improvement in its bending formability because these grains accommodate larger tensile strain along the ED during bending. As the temperature of the subsequent annealing treatment increases from 350 ℃ to 450 ℃, both the area fraction of the ED-oriented grains and the average grain size increase, and the residual dislocation density decreases owing to the promotion of boundary migration and occurrence of the recovery process at higher ***, the bending formability of both the 4%-precompressed and the 6%-precompressed samples increases with an increase in the annealing temperature. However, when the precompressed samples are annealed at 300 ℃, their bending formability is lower than that of the extruded alloy because the dislocations formed by precompression remain even after the subsequent annealing at this temperature.

关键词： Magnesium Extrusion Bending Formability Texture

Expression Analysis of Proline Metabolism-related Genes From Halophyte Arabis stelleri under Osmotic Stress Conditions

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Journal of Integrative Plant Biology 2010年第10期52卷 891-903页

作者： Yuchul Jung Jungan Park Yunjung Choi Jin-Gweon Yang donggiun Kim Beom-Gi Kim Kyunghee Roh dong-hee lee Chung-Kyoon Auh Sukchan lee Department of Genetic Engineering Sungkyunkwan University Institute of Life Science and Technology Sungkyunkwan University National Academy of Agricultural Science Rural Development Administration Department of Life Science Ewha Womans University Department of Biological Sciences Mokpo National University

Arabis stelleri var. japonica evidenced stronger osmotic stress tolerance than Arabidopsis thaliana. Using an A. thaliana microarray chip, we determined changes in the expression of approximately 2 800 genes between A. stelleri plants treated with 0.2 M mannitol versus mock-treated plants. The most significant changes in the gene expression patterns were in genes defining cellular components or in genes associated with the endomembrane system, stimulus response, stress response, chemical stimulus response, and defense response. The expression patterns of three de novo proline biosynthesis enzymes were evaluated in A. stelleri var. japonica seedlings treated with 0.2 M mannitol, 0.2 M sorbitol, and 0.2 M NaCI. The expression of At-pyrroline-5-carboxylate synthetase was not affected by NaCI stress but was similarly induced by mannitol and sorbitol. The proline dehydrogenase gene, which is known to be repressed by dehydration stress and induced by free L-proline, was induced at an early stage by mannitol treatment, but the level of proline dehydrogenase was increased later by treatment with both mannitol and NaCI. The level of free L-proline accumulation increased progressively in response to treatments with mannitol, sorbitol, and NaCI. Mannitol induced L-proline accumulation more rapidly than NaCI or sorbitol. These findings demonstrate that the osmotic tolerance of the novel halophyte, Arabis stelleri, is associated with the accumulation of L-proline.

关键词： Expression Analysis of Proline Metabolism-related Genes From Halophyte Arabis stelleri under Osmotic Stress Conditions

Aligned Ion Conduction Pathway of Polyrotaxane‑Based Electrolyte with Dispersed Hydrophobic Chains for Solid‑State Lithium–Oxygen Batteries

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Nano-Micro Letters 2025年第2期17卷 169-186页

作者： Bitgaram Kim Myeong‑Chang Sung Gwang‑hee lee Byoungjoon Hwang Sojung Seo Ji‑Hun Seo dong‑Wan Kim Department of Materials Science and Engineering Korea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea School of Civil Environmental and Architectural EngineeringKorea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea Materials Science and Chemical Engineering Center Institute for Advanced Engineering(IAE)Yongin 17180Republic of Korea

A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety *** study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves ***-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain *** this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 *** situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen *** situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability *** present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

关键词： Solid polymer electrolyte Lithium-oxygen batteries Polyrotaxane ion conductivity Hydrophobic chain

Torque Sharing Function Control of Switched Reluctance Machines with Reduced Current Sensors

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CES Transactions on Electrical Machines and Systems 2018年第4期2卷 355-362页

作者： Wei Peng Johan Gyselinck Jin-Woo Ahn dong-hee lee Bio ElectroUniversitéLibre de Bruxelles(ULB)BrusselsBelgium Mechanical Systems(BEAMS)Department UniversitéLibre de Bruxelles(ULB)BrusselsBelgium Department of Mechatronics Engineering Kyungsung UniversityBusanKorea

This paper presents a Torque Sharing Function(TSF)control of Switched Reluctance Machines(SRMs)with different current sensor placements to reconstruct the phase *** requires precise phase current information to ensure accurate torque *** proposed methods with different chopping transistors or a new PWM implementation require four or two current sensors to replace the current sensors on each phase regardless of the phase *** both approaches,the actual phase current can be easily extracted during the single phase conducting ***,how to separate the incoming and outgoing phase current values during the commutation region is the difficult issue to deal *** order to derive these two adjacent currents,the explanations and comparisons of two proposed methods are *** effectiveness is verified by experimental results on a four-phase 8/6 ***,the approach with a new PWM implementation is selected,which requires only two current sensors for reducing the number of *** control system can be more compact and cheaper.

关键词： Current sensor placement pulse width modulation(PWM) switched reluctance machines torque sharing function

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CES Transactions on Electrical Machines and Systems 2018年第4期2卷 337-338页

作者： Jin-Woo Ahn dong-hee lee Huijun Wang Young-Ju An Jianing Liang Gaolin Wang 不详 Kyungsung University Korea Beihang University China Pukyong National University Korea Chnese Academy of Science China Harbin Institute of Technology China

SWITCHED reluctance motor(SRM)is a doubly salient electric machine that relies on reluctance torque to rotate rather than electromagnetic torque,as implied on the *** term switch comes from the fact that the motor depends heavily on power switches for its *** was the reason that slowed the development of SRM since micro and power electronics were not so advanced.

关键词： rotate implied doubly

Investigation on the insecticidal limonoid content of commercial biopesticides and neem extract using solid phase extraction

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Journal of Agricultural Chemistry and Environment 2013年第4期2卷 81-85页

作者： Ji-Won lee Cho-Long Jin Ki Chang Jang Geun-Hyoung Choi hee-dong lee Jin Hyo Kim Chemical Safety Division National Academy of Agricultural Science RDA Suwon Republic of Korea Research Policy Planning Division Research Policy Bureau RDA Suwon Republic of Korea

Neem extract is an alternative insecticide for organic farming and is an allowed component for commercial biopesticide in Korea. However, crop protection properties are not consistent in commercial products. In this report, quantitative analysis of commercial biopesticides for the four insecticidal limonoids of neem extract-azadirachtin A, azadirachtin B, deacetylsalannin and salannin, was conducted through solid phase extraction method with lipophilic-hydrophilic balanced material. The recoveries of the four limonoids ranged from 80.5% to 105%, and their limit of quantitation ranged from 0.028 mg/L to 0.356 mg/L. On the five imported neem extracts, the total contents of the four bioactive limonoids extracted were from 321 mg/L to 5810 mg/L, but there were big variations in the relative composition of the limonoids. The total limonoidal concentrations in 23 commercial bio-pesticides made from neem showed from below LOQ to 7190 mg/L with significant differences in the relative composition. These differences determine the biopesticide’s efficacy on pests, therefore, tracking the active ingredients is necessary for the quality control of commercial bio-pesticides.

关键词： Solid Phase Extraction Azadirachitn Salannin Quantitative Analysis Biopesticide

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

K2Ti6O13 Nanoparticle-Loaded Porous rGO Crumples for Supercapacitors

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Nano-Micro Letters 2020年第1期12卷 115-123页

作者： Chongmin lee Sun Kyung Kim Hankwon Chang hee dong Jang Department of Nanomaterials Science and Engineering University of Science and TechnologyYuseong‑guDaejeon 34113Republic of Korea Resources Utilization Research Center Korea Institute of Geoscience and Mineral ResourcesYuseong‑guDaejeon 34132Republic of Korea

One-dimensional alkali metal titanates containing potassium,sodium,and lithium are of great concern owing to their high ion mobility and high specific surface *** those titanates are combined with conductive materials such as graphene,carbon nanotube,and carbon nanofiber,they are able to be employed as efficient electrode materials for *** hexa-titanate(K2Ti6O13,KTO),in particular,has shown superior electrochemical properties compared to other alkali metal titanates because of their large lattice parameters induced by the large radius of potassium ***,we present porous rGO crumples(PGC)decorated with KTO nanoparticles(NPs)for application to *** KTO NP/PGC composites were synthesized by aerosol spray pyrolysis and post-heat *** NPs less than 10 nm in diameter were loaded onto PGCs ranging from 3 to 5μ*** porous structure of the composites was obtained by the activation of rGO by adding an excessive amount of KOH to the *** KTO NP/PGC composite electrodes fabricated at the GO/KOH/TiO2 ratio of 1:3:0.25 showed the highest performance(275 F g−1)in capacitance with different KOH concentrations and cycling stability(83%)after 2000 cycles at a current density of 1 A g−1.

关键词： Potassium hexa-titanate Porous graphene crumples Supercapacitors