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Effects of homogenization temperature on microstructure and mechanical properties of high-speed-extruded Mg–5Bi–3Al alloy

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Journal of Magnesium and Alloys 2022年第10期10卷 2833-2846页

作者： jae Won Cha Sang-Cheol Jin jae-gil jung Sung Hyuk Park School of Materials Science and Engineering Kyungpook National University80 DaehakroDaegu 41566Republic of Korea Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

This study investigates the effects of billet homogenization temperature on the dynamic recrystallization behavior during high-speed extrusion and resultant microstructure and tensile properties of the Mg–5Bi–3Al(BA53,wt%)*** billets homogenized at 350 and450℃(350H and 450H billets)are extruded at a high speed of 69 m/*** 350H billet has a relatively smaller grain size and a higher abundance of fine Mg3Bi2particles compared to the 450H *** extrusion of the 350H billet,enhanced dynamic recrystallization occurs as a result of its finer grains and abundance of particles,while the growth of recrystallized grains is suppressed by the grain-boundary pinning effect of ***,the extruded 350H material is characterized by smaller grains,relatively greater number of Mg3Bi2particles,and a higher internal strain energy than the extruded 450H *** tensile strength of the extruded 350H material is higher than that of the extruded 450H material owing to stronger grain-boundary hardening,particle hardening,and strain hardening *** extruded 350H material also exhibits a higher tensile elongation as its smaller grains inhibit the formation of crack-inducing undesirable twins during *** results from this study demonstrate that a decrease in the homogenization temperature from 450 to 350℃leads to improved strength and ductility in the high-speed-extruded BA53 material.

关键词： Mg–Bi–Al alloy High-speed extrusion Homogenization Dynamic recrystallization Tensile properties

Influence of undissolved second-phase particles on dynamic recrystallization behavior of Mg–7Sn–1Al–1Zn alloy during low-and high-temperature extrusions

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Journal of Materials Science & Technology 2021年第12期71卷 87-97页

作者： Hyun Ji Kim Sang-Cheol Jin jae-gil jung Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon51508Republic of Korea

This study investigates the effects of fine and coarse undissolved particles in a billet of the Mg–7 Sn–1 Al–1 Zn(TAZ711)alloy on the dynamic recrystallization(DRX)behavior during hot extrusion at low and high temperatures and the resultant microstructure and mechanical properties of the *** this end,partially homogenized(PH)and fully homogenized(FH)billets are extruded at temperatures of250 and 450°*** PH billet contains fine and coarse undissolved Mg_(2) Sn particles in the interdendritic region and along the grain boundaries,*** fine particles(<1μm in size)retard DRX during extrusion at 250°C via the Zener pinning effect,and this retardation causes a decrease in the area fraction of dynamically recrystallized(DRXed)grains of the extruded *** addition,the inhomogeneous distribution of fine particles in the PH billet leads to the formation of a bimodal DRXed grain structure with excessively grown grains in particle-scarce *** contrast,in the FH billet,numerous nanosized Mg_(2) Sn precipitates are formed throughout the material during extrusion at 250°C,which,in turn,leads to the formation of small,uniform DRXed grains by the grain-boundary pinning effect of the *** the PH billet is extruded at the high temperature of 450°C,the retardation effect of the fine particles on DRX is weakened by their dissolution in theα-Mg matrix and the increased extent of thermally activated grain-boundary *** contrast,the coarse Mg_(2) Sn particles in the billet promote DRX during extrusion through the particle-stimulated nucleation phenomenon,which results in an increase in the area fraction of DRXed *** both low and high extrusion temperatures,the extruded material fabricated using the PH billet,which contains both fine and coarse undissolved particles,has a lower tensile strength than that fabricated using the FH billet,which is virtually devoid of second-phase *** lower strength of the former is attributed mai

关键词： Mg–Sn alloy Second-phase particle Extrusion Homogenization Dynamic recrystallization

Prediction of grain structure in direct-chill cast Al–Zn–Mg–Cu billets using cellular automaton-finite element method

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Progress in Natural Science:Materials International 2021年第3期31卷 434-441页

作者： Min-Seok Kim Sang-Hwa Lee jae-gil jung Kwangjun Eah Department of Materials Science and Engineering Gachon University Metallic Materials Division Korea Institute of Materials Science Department of Materials Science and Engineering Yonsei University

A cellular automaton-finite element(CA-FE) model was used to predict the solidification grain structure of permanent mold cast A7086 alloy. In this model, a Gaussian distribution of nucleation sites was adopted, and the Kurz-Giovanola-Trivedi model was extended to a multicomponent Al–Zn–Mg–Cu alloy system to determine the growth kinetics of the dendrite tip. For describing the Gaussian distribution of nucleation sites on the mold surface, an empirical relationship between the initial cooling rate of the melt and the nucleation density was proposed. Under various casting conditions, the calculated grain structures agreed well with the experimental results. Subsequently, the model was applied to the direct-chill(DC) cast billets, and the simulated grain structures reproduced well the experimental results. This confirmed that the current CA-FE model can be used practically and effectively in DC casting processes.

关键词： Cellular automaton-finite element (CA-FE) model Direct-chill casting Al–Zn–Mg–Cu alloy A7068 alloy Grain structure

Comprehensive review of advances in machine-learning-driven optimization and characterization of perovskite materials for photovoltaic devices

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Journal of Energy Chemistry 2025年第2期101卷 298-323页

作者： Bonghyun Jo Wenning Chen Hyun Suk jung School of Advanced Materials Science and Engineering Sungkyunkwan University SKKU Institute of Energy Science and Technology (SIEST) Sungkyunkwan University Department of Future Energy Engineering Sungkyunkwan University

Perovskite solar cells(PSCs) have developed rapidly,positioning them as potential candidates for nextgeneration renewable energy ***,conventional trial-and-error approaches and the vast compositional parameter space continue to pose challenges in the pursuit of exceptional performance and high stability of perovskite-based *** increasing demand for novel materials in optoelectronic devices and establishment of substantial databases has enabled data-driven machinelearning(ML) approaches to swiftly advance in the materials *** review succinctly outlines the fundamental ML procedures,techniques,and recent breakthroughs,particularly in predicting the physical characteristics of perovskite ***,it highlights research endeavors aimed at optimizing and screening materials to enhance the efficiency and stability of ***,this review highlights recent efforts in using characterization data for ML,exploring their correlations with material properties and device performance,which are actively being researched,but they have yet to receive significant ***,we provide future perspectives,such as leveraging Large Language Models(LLMs) and text-mining,to expedite the discovery of novel perovskite materials and expand their utilization across various optoelectronic fields.

关键词： Characterization Data-driven machine learning Perovskite materials Perovskite solar cell

Novel transparent high-entropy sesquioxide ceramics with high physicochemical plasma etching resistance

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JOURNAL OF ADVANCED CERAMICS 2025年第1期14卷 163-176页

作者： Shin, Yu-Bin Ham, Su Been Kim, Ha-Neul Kim, Mi-Ju Ko, jae-Woong Lee, jae-Wook Park, Young-Jo Kim, jung-Hyung Lee, Hyo-Chang jung, Young Hwa Lee, jung Woo Ma, Ho Jin Korea Inst Mat Sci Nano Mat Res Div Chang Won 51508 Gyeongsangnam South Korea Pusan Natl Univ Dept Mat Sci & Engn Pusan 46241 South Korea Korea Res Inst Stand & Sci Semicond Integrated Metrol Team Daejeon 34113 South Korea Korea Aerosp Univ Dept Semicond Sci Engn & Technol Goyang 10540 South Korea Korea Aerosp Univ Sch Elect & Informat Engn Goyang 10540 South Korea Pohang Accelerator Lab PLS II Beamline Div Pohang 37673 South Korea

High-entropy ceramics exhibit novel intrinsic properties. Hence, they have been explored for a wide range of applications ranging from thermal insulation and energy storage to advanced optical components. Recently, the semiconductor industry has faced a demand for higher-performance chips, necessitating higher aspect ratios in wafer fabrication and further miniaturization of linewidths. Therefore, novel materials with high plasma etching resistance and minimal contaminant generation are needed. The plasma-etching resistance displayed by high-entropy ceramics can be an innovative solution to this emerging challenge. In this study, we successfully fabricated single-phase high-entropy sesquioxide ceramics with high optical transparency, dense microstructure, and minimal residual pores. A structural analysis of the fabricated samples revealed a single-phase structure with excellent phase homogeneity. An evaluation of the plasma-etching resistance of high-entropy ceramics revealed for the first time a low etching rate of 8 nm/h compared with that of conventional plasma-resistant materials. These comprehensive characterizations of high-entropy ceramics indicate that they are promising candidates for significantly improving the production yield of semiconductors and for a wide range of potential applications, such as next-generation active optical ceramics.

关键词： high-entropy ceramics plasma etching resistance transparent ceramics sintering semiconductor manufacturing

The H∞ Robust Stability and Performance Conditions for Uncertain Robot Manipulators

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 270-272页

作者： Geun Il Song Hae Yeon Park jung Hoon Kim the Department of Electrical Engineering Pohang University of Science and Technology (POSTECH) the Department of Electrical Engineering Pohang University of Science and Technology (POSTECH) the Institute for Convergence Research and Education in Advanced Technology Yonsei University

Dear Editor,H∞This letter develops a new framework for the robust stability and performance conditions as well as the relevant controller synthesis with respect to uncertain robot *** often exist model uncertainties between the nominal model and the real robot manipulator and disturbances. Hence, dealing with their effects plays a crucial role in leading to high tracking performances, as discussed in [1]–[5].

关键词： Robot applications

Gut–brain axis and environmental factors in Parkinson's disease:bidirectional link between disease onset and progression

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Neural Regeneration Research 2025年第12期20卷 3416-3429页

作者： Soo jung Park Kyung Won Kim Eun Jeong Lee Department of Brain Science Ajou University School of MedicineSuwonSouth Korea Department of Life Science and Multidisciplinary Genome Institute Hallym UniversityChuncheonSouth Korea

Parkinson's disease has long been considered a disorder that primarily affects the brain,as it is defined by the dopaminergic neurodegeneration in the substantia nigra and the brain accumulation of Lewy bodies containingα-synuclein *** recent decades,however,accumulating research has revealed that Parkinson's disease also involves the gut and uncovered an intimate and important bidirectional link between the brain and the gut,called the“gut–brain axis.”Numerous clinical studies demonstrate that gut dysfunction frequently precedes motor symptoms in Parkinson's disease patients,with findings including impaired intestinal permeability,heightened inflammation,and distinct gut microbiome profiles and ***,α-synuclein deposition has been consistently observed in the gut of Parkinson's disease patients,suggesting a potential role in disease ***,individuals with vagotomy have a reduced Parkinson's disease *** these observations,researchers have hypothesized thatα-synuclein accumulation may initiate in the gut and subsequently propagate to the central dopaminergic neurons through the gut–brain axis,leading to Parkinson's *** review comprehensively examines the gut's involvement in Parkinson's disease,focusing on the concept of a gut-origin for the *** also examine the interplay between altered gut-related factors and the accumulation of pathologicalα-synuclein in the gut of Parkinson's disease *** the accessibility of the gut to both dietary and pharmacological interventions,targeting gut-localizedα-synuclein represents a promising avenue for developing effective Parkinson's disease therapies.

关键词： gut inflammation gut microbiome gut-brain axis micro/nano-plastics Parkinson’s disease α-synuclein

TMEM39A and TMEM131 facilitate bulk transport of ECM proteins through large COPII vesicle formation

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Journal of Genetics and Genomics 2025年第2期52卷 189-203页

作者： Jee Young Sung Ga-Eun Lim Jarim Goo Kyung Jin jung Jeong Min Chung Hyun Suk jung Yong-Nyun Kim jaegal Shim Cancer Metastasis Branch Research InstituteNational Cancer Center323 Ilsan-roGoyang-siGyeonggi-do10408Republic of Korea Experimental Clinical Research Center Biomedical Research InstituteSeoul National University Bundang HospitalSeongnamGyeonggi-do13620Republic of Korea Department of Biochemistry College of Natural SciencesKangwon National UniversityChuncheonKangwon-do24341Republic of Korea

The growth of Caenorhabditis elegans involves multiple molting processes,during which old cuticles are shed and new cuticles are rapidly *** process requires the regulated bulk secretion of cuticle *** transmembrane protein-39(TMEM-39)mutant exhibits distinct dumpy and ruptured phenotypes characterized by notably thin ***-39 primarily co-localizes with the coat protein II complex(COPII)in large vesicles rather than small COPII *** TMEM-39-associated large vesicles(TMEM-39-LVs)form robustly during the molting period and co-localize with various extracellular matrix components,including BLI-1 collagen,BLI-3 dual oxidase,and *** immunoprecipitation using TMEM39A-FLAG and proteomics analysis in human sarcoma cells,we identify TMEM39A-associated proteins,including *** of TMEM131 results in reduced TMEM39A-LV formation and collagen secretion in both *** and human sarcoma cells,indicating a cooperative role between TMEM39A and TMEM131 in the secretion of extracellular components through the formation of large COPII *** the conservation of TMEM39A and its associated proteins between *** and humans,TMEM39A-LVs may represent a fundamental machinery for rapid and extensive secretion across metazoans.

关键词： Bulk secretion Collagen COPII ECM TMEM39A TMEM131

EXPERIMENTAL ESTIMATION OF A SCALING EXPONENT FOR TIP VORTEX CAVITATION VIA ITS INCEPTION TEST IN FULL-AND MODEL-SHIP

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Journal of Hydrodynamics 2012年第5期24卷 658-667页

作者： LEE Jeung-Hoon jung jae-Kwon LEE Kyung-Jun HAN jae-Moon PARK Hyung-gil SEO Jong-Soo Samsung Ship Model Basin(SSMB) Marine Research InstituteSamsung Heavy IndustriesScience TownDaejeon 305-380Korea

Tip vortex cavitation noise of marine propeller became primary concems to reduce hazardous environmental impacts from commercial ship or to keep the underwater surveillance of naval ships. The investigations of the tip vortex and its induced noise are normally conducted through the model test in a water cavitation tunnel. However the Reynolds number of model-test is much smaller than that of the full-scale, which subsequently results in the difference of tip vortex cavitation inception. Hence, the scaling law between model- and full-scales needs to be identified prior to the prediction and assessment of propeller noise in full scale. From previous researches, it is generally known that the incipient caivtation number of tip vortex can be represented as a power of the Reynolds number. However, the power exponent for scaling, which is the main focus of this research, has not been clearly studied yet. This paper deals with the estimation of scaling exponent based on tip vortex cavitation inception test in both full- and model-scale ships. Acoustical measurements as well as several kind of signal processing technique for an inception criterion suggest the scaling exponent as 0.30. The scaling value proposed in this study shows slight difference to the one of most recent research. Besides, extrapolation of model-ship noise measurement using the proposed one predicts the full-scale noise measurement with an acceptable discrepancy.

关键词： tip vortex cavitation underwater radiated noise scaling exponent