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Journal of Materiomics 2024年第3期10卷 632-642页

作者： Su-Hwan Go seok-jung park Seung-Hyun Kim seok-June Chae Eun-Ji Kim Geun-Su Lee Sahn Nahm Department of Materials Science and Engineering Korea UniversitySeoul02841Republic of Korea

0.96(K_(0.5)Na_(0.5-z)Li_(z))(Nb_(0.92)Sb_(0.08))O_(3)-0.04(Ca_(0.5)Sr_(0.5))ZrO_(3)[(KN_(0.5-z)L_(z))NS-CSZ]piezoceramics(0≤z≤0.04)were aligned in the[001]orientation using 3%(in mole)NaNbO_(3)templates with a large Lotgering factor(>97%).Their crystal structures transformed from the orthorhombic-pseudocubic(O-P)structure to the orthorhombic-tetragonal-pseudocubic(O-T-P)structure with an increasing *** P structure was interpreted as a rhombohedral R3m *** piezoelectricity of the compositions increased after[001]-texturing,and the enhancement was proportional to the O phase *** composition(z=0.03)exhibited the highest piezoelectric constant(d_(33);670 pC/N)and electromechanical coupling factor(k_(p);0.56).Piezoelectric energy harvesters were produced using the untextured and textured samples(z=0.03).The textured harvester delivered a large power density of 26.6 mW/mm^(3),which was larger than that of the untextured harvester owing to the enhanced kp and d_(33)×g_(33) of the textured piezoceramic.A multilayer actuator was produced using the textured sample(z=0.03),and it exhibited a large acceleration(44.2 G)and displacement(±3,730 mm)at±25 ***,the[001]-textured(KN_(0.47)L_(0.03))NS-CSZ piezoceramic is suitable for piezoelectric energy harvesters and actuators.

关键词： KNN-Based piezoceramic Lead-free Energy harvester Actuator Reactive template grain growth

Impregnation approach for poly(vinylidene fluoride)/tin oxide nanotube composites with high tribological performance

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Journal of Materials Science & Technology 2020年第2期37卷 19-25页

作者： Min Su park Jin Kyu Kim Tong-seok Han jung Tae park Jong Hak Kim Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul03722Korea Department of Civil and Environmental Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul03722Korea Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul05029Korea

We report a composite material with the high tribological performance,which consists of onedimensional SnO2 nanotubes(ST)and a high molecular weight poly(vinylidene fluoride)(PVDF)matrix in terms of *** of PVDF in N,N-dimethylformamide(DMF)resulted in a facile penetration of PVDF into the inner hollow voids of ST,leading to the close *** between PVDF and ST results in a beneficial effect on the chain arrangement of PVDF,providing anα-phase with better tribological *** ST incorporation,the friction coefficient decreased by 85.0%to 0.408,and the specific wear rate decreased by 69.1%to 0.412,demonstrating the pivotal role of ST as a self-lubricating material due to a large interactive area and PVDF chain rearrangement.

关键词： SnO2 nanotube Composite Friction coefficient Wear rate

Effect of Al coating conditions on laser weldability of Al coated steel sheet

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中国有色金属学会会刊：英文版 2009年第4期19卷 946-951页

作者： jung-Han LEE Jong-Do KIM Jin-seok OH Seo-Jeong park Graduate School Korea Marine University Division of Marine Engineering System Korea Marine University Welding Research Center

Al coated steel sheets with excellent heat resistance,thermal reflection,and corrosion resistance are widely used in various *** laser weldability of the Al coated steel sheet for full penetration welding was *** phenomenon caused by intermixed aluminum and behavior of aluminum in the weld were *** coated steel sheets that have various thickness and coating mass were prepared for laser *** effects of parameters such as welding conditions and Al coating conditions were *** content mixed in the weld after laser welding was evaluated,and then a correlation between the mixed Al and mechanical properties was *** results show that the Al-rich zones which have Fe-Al intermetallic compounds are found in the *** intermetallic compounds cause the decreased strength of the weld.

关键词：铝合金焊接钢板焊接激光焊接 Al涂层金属间化合物涂层钢板涂层质量焊接条件

A feasible route to produce 1.1 GPa ferritic-based low-Mn lightweight steels with ductility of 47%

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Journal of Materials Science & Technology 2022年第22期117卷 225-237页

作者： Kwang Kyu Ko Hyo Ju Bae Eun Hye park Hyeon-Uk Jeong Hyoung seok park Jae seok Jeong jung Gi Kim Hyokyung Sung Nokeun park Jae Bok Seol Department of Materials Engineering and Convergence Technology Center for K-metalGyeongsang National University(GNU)Jinju 52828South Korea School of Materials Science and Engineering Yeungnam UniversityGyeongbuk 38541South Korea Materials Research Team R&D Hyundai MobisYongin 16891South Korea Materials Technology Development Team Doosan Heavy Industries&ConstructionChangwon 51711South Korea

High- and medium-Mn (H/M-Mn) base lightweight steels are a class of ultrastrong structural materials with high ductility compared to their low-Mn counterparts with low strength and poor ***, producing these H/M-Mn materials requires the advanced or high-tech manufacturing techniques, which can unavoidably provoke labor and cost concerns. Herein, we have developed a facilestrategy that circumvents the strength–ductility trade-off in low-Mn ferritic lightweight steels, by employing low-temperature tempering-induced partitioning (LTP). This LTP treatment affords a typical Fe-2.8Mn-5.7Al-0.3C (wt.%) steel with a heterogeneous size-distribution of metastable austenite embeddedin a ferrite matrix for partitioning more carbon into smaller austenite grains than into the larger austenite ones. This size-dependent partitioning results in slip plane spacing modification and lattice strain,which act through dislocation engineering. We ascribe the simultaneous improvement in strength andtotal elongation to both the size-dependent dislocation movement in austenite grains and the controlleddeformation-induced martensitic transformation. The low-carbon-partitioned large austenite grains increase the strength and ductility as a consequence of the combined martensitic transformation andhigh dislocation density-induced hardening and by interface strengthening. Additionally, high-carbonpartitioned small austenite grains enhance the strength and ductility by planar dislocation glide (inthe low strain regime) and by cross-slipping and delayed martensitic transformation (in the high strainregime). The concept of size-dependent dislocation engineering may provide different pathways for developing a wide range of heterogeneous-structured low-Mn lightweight steels, suggesting that LTP maybe desirable for broad industrial applications at an economic cost.

关键词： Low-Mn lightweight steel Carbon partitioning Metastable austenite Dislocation movement

Pyruvate dehydrogenase kinase is a negative regulator of interleukin-10 production in macrophages

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Journal of Molecular Cell Biology 2020年第7期12卷 543-555页

作者： Yi Rang Na Daun jung Juha Song Jong-Wan park jung Joo Hong Seung Hyeok seok Macrophage Lab Department of Microbiology and Immunology and Institute of Endemic DiseaseSeoul National University College of MedicineChongno-guSeoul 03080Republic of Korea Department of Biomedical Science BK21-Plus Education ProgramSeoul National University College ofMedicineJongno-guSeoul 03080Republic of Korea Department of Pharmacology Seoul National University College of MedicineJongno-guSeoul 03080Republic of Korea Cancer Research Institute and Ischemic/Hypoxic Disease Institute Seoul National University College ofMedicineJongno-guSeoul 03080Republic of Korea National Primate Research Center Korea Research Institute of Bioscience and BiotechnologyCheongju 28116Republic of Korea

Interleukin-10(IL-10)is the most potent anti-inflammatory cytokine in the body and plays an essential role in determining outcomes of many inflammatory *** metabolism is a critical determinant of immune cell function;however,it is currently unclear whether metabolic processes are specifically involved in IL-10 *** this study,we aimed to find the central metabolic molecule regulating IL-10 production of macrophages,which are the main producers of *** analysis identified that metabolic changes were predominantly enriched in Kupffer cells at the early inflammatory phase of a mouse endotoxemia *** them,pyruvate dehydrogenase kinase(PDK)-dependent acute glycolysis was negatively involved in IL-10 *** or knockdown of PDK selectively increased macrophage IL-10 ***,PDK inhibition increased IL-10 production via profound phosphorylation of adenosine monophosphate(AMP)-activated protein kinase alpha 1(AMPKα1)by restricting glucose uptake in lipopolysaccharide-stimulated ***α1 consequently activated p38 mitogen-activated protein kinase,c-Jun N-terminal kinase,and cyclic AMP-responsive element-binding protein to regulate IL-10 *** study uncovers a previously unknown regulatory mechanism of IL-10 in activated macrophages involving an immunometabolic function of PDK.

关键词： macrophage pyruvate dehydrogenase kinase AMP-activated protein kinase interleukin-10

Multidimensional Hybrid Architecture Encapsulating Cobalt Oxide Nanoparticles into Carbon Nanotube Branched Nitrogen-Doped Reduced Graphene Oxide Networks for Lithium–Sulfur Batteries

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Energy & Environmental Materials 2022年第2期5卷 555-564页

作者： Jeong seok Yeon Young Hun Ko Tae Ho park Hyunyoung park Jongsoon Kim Ho seok park School of Chemical Engineering College of EngineeringSungkyunkwan University2066Seobu-roJangan-guSuwon-si Gyeonggi-do 440-746Korea Advanced Batteries Research Center Korea Electronics Technology Institute25Saenari-roBundang-guSeongnam-si Gyeonggi-do 13509Korea Department of Energy Science Sungkyunkwan University2066Seobu-roJangan-guSuwon-si Gyeonggi-do 440-746Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746South Korea

Lithium–sulfur batteries(LSBs)are regarded as promising candidates for the next-generation energy storage devices owing to their high-theoretical capacity(1675 mAh g^(−1))and affordable ***,several limitations of LSBs such as the lithium polysulfide shuttle,large volume expansion,and low electrical conductivity of sulfur need to be resolved for practical *** address these limitations,herein,a multidimensional architectured hybrid(Co@CNT/nG),where Co_(3)O_(4) nanoparticles are encapsulated into threedimensional(3D)porous N-doped reduced graphene oxide interconnected with carbon nanotube(CNT)branches,is synthesized through a simple pyrolysis *** synergistic effect achieved through the homogeneously distributed and encapsulated Co_(3)O_(4) nanoparticles,the interconnected CNT branches,and the 3D hierarchical porous structure and N-doping of Co@CNT/nG significantly suppresses the shuttle effect of lithium polysulfides and enhances the conversion redox kinetics for the improved sulfur *** validate this effect through various measurements including symmetric cells,Li_(2)S nucleation,shuttle currents,Tafel slopes,diffusion coefficients,and post-mortem ***,Co@CNT/nG-70S-based LSB cells achieve a high-specific capacity of 1193.1 mAh g^(−1) at 0.1 C and a low capacity decay rate of 0.030%per cycle for 700 cycles at 5 C,delivering a high areal capacity of 5.62 mAh cm^(−2) even with a loading of 6.5 mg cm^(−2).

关键词： graphene/CNT hybrid lithium-sulfur batteries multidimensional architecture nanoparticle encapsulation redox promoter

Density functional theory study on the role of ternary alloying elements in TiFe-based hydrogen storage alloys

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Journal of Materials Science & Technology 2021年第33期92卷 148-158页

作者： Won-seok Ko Ki Beom park Hyung-Ki park School of Materials Science and Engineering University of UlsanUlsan 44610Republic of Korea Functional Materials and Components R&D Group Korea Institute of Industrial TechnologyGangneung 25440Republic of Korea

The role of additional ternary alloying elements on the performance of stationary TiFe-based hydrogen storage alloys was investigated based on first-principles density functional theory *** a basic step for examinations,the site preference of each alloying element in the stoichiometric and nonstoichiometric B2TiFe compounds was clarified considering possible antisite *** on the revealed site preference,the effect of various possible ternary elements on the hydrogen storage was examined by focusing on the formation enthalpies of TiFeH and TiFeH_(2) hydrides,which were closely related to the change in the location of plateaus in the pressure-composition-temperature *** physical properties such as the volume expansion due to hydride formation were also examined to provide additional criteria for selecting optimum alloying conditions in future alloying design *** alloying elements that maximize the grain boundary embrittlement due to the solute segregation were proposed for the enhanced initial activation of TiFe-based hydrogen storage alloys.

关键词： Hydrogen storage alloy Titanium-iron Density functional theory calculation Metallic hydride

Perspective on High-Energy Carbon-Based Supercapacitors

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Energy & Environmental Materials 2020年第3期3卷 286-305页

作者： Qingyun Dou Ho seok park School of Chemical Engineering Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746Korea

Supercapacitors based on carbon materials have advantages such as high power density,fast charging/discharging capability,and long lifetime stability,playing a vital role in the field of electrochemical energy storage *** further expand the practical applications of carbon-based supercapacitors,their energy density,which is essentially determined by the specific capacitance and operating voltage,should be *** review provides fundamental knowledge on achieving high energy density of *** first address the relationship of the features of carbon materials,such as the surface area,pore size distribution,and surface functional groups,with their electrochemical performances,such as the gravimetric and volumetric capacitance,surface pseudocapacitance,and operating ***,we discuss the properties of electrolytes from nonaqueous and aqueous to hybrid one from the thermodynamic and kinetic aspects,and present their effects on capacitance and operating ***,we illustrate different cell design strategies and their basic principles for increasing operating *** also highlight the recent advances related to these fields and provide our insight into high-energy supercapacitors.

关键词： carbon material cell design electrolyte energy density supercapacitors

Visualization of flow structures inside a conical spouted bed by electrical capacitance volume tomography

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Particuology 2019年第1期17卷 15-25页

作者： Hoon Chae park Hang seok Choi Department of Environmental Engineering Yonsei UniversityWonju 26493Republic of Korea

Electrical capacitance volume tomography (ECVT) was conducted to measure instantaneous gas–solid flow structures in a conical spouted bed. The sensor has 24 electrodes/channels and was used to make three-dimensional measurements of the solid volume fraction. Flow structures in the conical spouted bed were analyzed using quantitative ECVT images. Three-dimensional images of gas–solid flow structures and time-averaged vertical and radial solid volume fraction profiles are presented. Different fluidization regimes in spouted beds were characterized by analyzing pressure fluctuation signals and ECVT images. ECVT was shown to be robust and powerful for the three-dimensional visualization and quantitative measurement of a gas–solid fluidization system.

关键词： Conical spouted bed Electrical capacitance volume tomography Multiphase flow

Effects of Flower Buds Extract of Tussilago farfara on Focal Cerebral Ischemia in Rats and Inflammatory Response in BV2 Microglia

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Chinese Journal of Integrative Medicine 2018年第11期24卷 844-852页

作者： Ji Hye Hwang Vinoth Kumar R seok Yong Kang Hyo Won jung Yong-Ki park Department of Acupuncture and Moxibustion Medicine College of Korean Medicine Gachon University Department of Herbology College of Korean Medicine Dongguk University

Objective： To investigate the effects of the flower buds extract of Tussilago farfara Linné（Farfarae Flos; FF） on focal cerebral ischemia through regulation of inflammatory responses in activated microglia. Methods： Brain ischemia was induced in Sprague-Dawley rats by a transient middle cerebral artery occlusion（t MCAO） for 90 min and reperfusion for 24 h. Twenty rats were randomly divided into 4 groups（n=5 per group）： normal, t MCAO-induced ischemic control, t MCAO plus FF extract 300 mg/kg-treated, and t MCAO plus MK-801 1 mg/kg-treated as reference drug. FF extract（300 mg/kg, p.o.） or MK-801（1 mg/kg, i.p.） was administered after reperfusion. Brain infarction was measured by 2,3,5,-triphenyltetrazolium chloride staining. Neuronal damage was observed by haematoxylin eosin, Nissl staining and immunohistochemistry using anti-neuronal nuclei（Neu N）, anti-glial fibril ary acidic protein（GFAP）, and antiCD11 b/c（OX42） antibodies in ischemic brain. The expressions of inducible nitric oxide synthase（i NOS）, tumor necrosis factor（TNF-α）, and hypoxia-inducible factor-1 a（HIF-1α） were determined by Western blot. BV2 microglial cel s were treated with FF extract or its main bioactive compound, tussilagone with or without lipopolysaccharide（LPS）. Nitric oxide（NO） production was measured in culture medium by Griess assay. The expressions of i NOS, COX-2 and pro-inflammatory cytokines mRNA were analyzed by reverse transcription-polymerase chain reaction. The expression of i NOS, and COX-2 proteins, the phosphorylation of ERK1/2, JNK, and p38 MAPK and the nuclear expression of NF-κB p65 in BV2 cells were determined by Western blot. Results： FF extract significantly decreased brain infarctions in ischemic rats（P〈0.01）. The neuronal death and the microglia/astrocytes activation in ischemic brains were inhibited by FF extract. FF extract also suppressed i NOS, TNF-α, and HIF-1α expression in ischemic brains. FF extract（0.2 and 0.5 mg/m L, P〈0.01） and tussilagone 20 and 50 μmol/L, P〈0

关键词： Tussilago farfara focal cerebral ischemia inflammation microglia tussilagone