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Journal of Materials Science & Technology 2022年第22期117卷 8-22页

作者： young-kyun kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea Korea Institute of Materials Science(kimS) Changwon 51508Republic of Korea

High-entropy alloys(HEAs)with interstitial atoms that are produced by additive manufacturing have gained intensive interest in the materials science community because of their suitability for constructing high-strength net-shape ***,a strategy to additionally enhance the strength of selective laser melted carbon-containing HEAs was *** as-built carbon-containing HEAs(C_(x)(Cr_(20)Mn_(20)Fe_(20)Co_(20)Ni_(20))_(100-x)(x=0.5 at.%,1.0 at.%,and 1.5 at.%))contain supersaturated carbon,and the extent of supersaturation increases as the carbon content *** subjected to aging treatment at 650°C for 1 h,the microstructure of the three alloys did not change at the grain ***,the microstructure at the sub-grain scale changed markedly,and these changes influenced the tensile properties and deformation *** particular,the tensile strength of aged 1.5C-HEA at 650°C was∼1.2 GPa at room temperature,which is higher than those reported for CrMnFeCoNi ***,the main deformation mechanism changed from deformation twinning to dislocation-mediated slip,resulting in much higher strain hardening capacity after the aging *** work led to the development of an alternative promising method that involves tailoring the microstructure,to enhance the mechanical properties of additively manufactured metallic materials that contain interstitial atoms.

关键词： Selective laser melting High-entropy alloy Carbon contents Aging Microstructure evolution Tensile property Deformation mechanism

Effect of carrier gas species on the microstructure and compressive deformation behaviors of ultra-strong pure copper manufactured by cold spray additive manufacturing

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Journal of Materials Science & Technology 2022年第2期97卷 264-271页

作者： young-kyun kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea

Cold spray(CS)which has recently become a promising additive manufacturing(AM)technology,was used to fabricate ultra-strong pure *** addition,the effects of carrier gas species on the microstructural characteristics,mechanical properties and deformation mechanisms were systemically *** CSAM copper manufactured with N_(2) carrier gas reveals a heterogeneous bimodal microstructure consisting of ultra-fine grains at the particle interface and relatively coarse grains in inner *** He carrier gas,a homogeneous grain structure consisting of ultra-fine grains in most areas was *** tests showed that N_(2) and He carrier gasses enabled ultra-high yield strengths of 340 and415 MPa,*** values are comparable to severely plastic deformed copper,which has extremely low ductility and shape *** the other hand,both samples showed a strain-softening phenomenon that does not commonly occur at room *** deformation microstructures revealed that dynamic recovery(DRV)and dynamic recrystallization(DRX)phenomena were generated despite being deformed at room *** on the above findings,the overall deformation mechanisms according to the carrier gas species in the CSAM copper manufacturing process were ***,the work hardening and softening behaviors of CSAM Cu are predicted by using a constitutive equation.

关键词： Cold spray additive manufacturing Carrier gas Pure Cu Mechanical properties Deformation behavior

1.45 GPa ultrastrong cryogenic strength with superior impact toughness in the in-situ nano oxide reinforced CrMnFeCoNi high-entropy alloy matrix nanocomposite manufactured by laser powder bed fusion

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Journal of Materials Science & Technology 2022年第2期97卷 10-19页

作者： young-kyun kim Min-Chul kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea Korea Atomic Energy Research Institute(KAERI) Daejeon 34057Republic of Korea

CrMnFeCoNi high-entropy alloys(HEAs)exhibit an excellent combination of tensile strength and ductility at cryogenic *** study led to the introduction of a new method for the development of high-performance CrMnFeCoNi HEAs at cryogenic temperatures by jointly utilizing additive manufacturing(AM)and the addition of interstitial *** interstitial oxygen present in the powder feedstock was transformed into beneficial nano-sized oxides during AM *** HEA nanocomposite fabricated using laser powder bed fusion(L-PBF)not only contains heterogeneous grains and substructures but also a high number density of nano-sized *** tensile results revealed that the L-PBF HEA nanocomposite has superior yield strengths of 0.77 GPa and 1.15 GPa,and tensile strengths of 0.92 GPa and 1.45 GPa at 298 K and 77 K,*** addition,the Charpy impact energies of the samples tested at 298 K and 77 K were measured as 176.2 J and 103.7 J,*** results indicate that the L-PBF HEA nanocomposite successfully overcomes the well-known strength-toughness *** tensile deformation microstructure contained a relatively large number of deformation twins(DTs)at cryogenic temperature,a possible consequence of the decrease in the stacking fault energy with decreasing *** the other hand,cracks were found to propagate along the grain boundaries at room temperature,whereas a transgranular crack was observed at cryogenic temperature in the specimens fractured as a result of the Charpy impact.

关键词： Laser powder bed fusion High-entropy alloy matrix nanocomposite Nano-oxide:cryogenic Tensile Impact toughness

2.47 GPa grade ultra-strong 15Co-12Ni secondary hardening steel with superior ductility and fracture toughness

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Journal of Materials Science & Technology 2021年第7期66卷 36-45页

作者： young-kyun kim Kyu-Sik kim young-Beum Song Jung Hyo Park Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon22212Republic of Korea Agency for Defense Development(ADD) Yuseong-guDaegeon34186Republic of Korea

This study investigated the effect of multi-step heat treatment on the microstructure, mechanical properties and fracture behavior of thick 15 Co-12 Ni secondary hardening steel. As-quenched sample was found to have elongated prior austenite grain(PAG) and coarse lenticular martensitic structure. On the other hand, heat-treated sample was observed to have fine lenticular martensitic structure due to fine PAG size and a lot of nano-sized carbides. Also, after heat treatment, nano-scale reverted austenite film was formed at the martensite interfaces. The heat-treated sample showed 2.47 GPa superior tensile strength and superior elongation of about 12 %. The high strength was mainly due to fine block size and high number density of nano-sized carbides. The average value of plane strain fracture toughness(KIC) was 29.3 MPa m1/2, which indicated a good fracture toughness even with the high tensile strength. The tensile fracture surface was observed to have ductile fracture mode(cup-and-cone) and the formation of about ~1 μm ultra-fine dimples. In addition to this, nano-sized carbides were observed within the *** findings suggested that the nano-sized carbide had a positive effect not only on the strength but also on the ductility of the alloy. The fractured surface after toughness test, also showed ductile fracture mode with a lot of dimples. Based on the above results, correlation among microstructural evolution,deformation and fracture mechanisms along the heat-treatment was also discussed.

关键词： Ultra-high strength High Co-Ni secondary hardening steel Microstructure Tensile properties Fracture toughness Reverted austenite

The SARS-CoV-2 spike protein induces lung cancer migration and invasion in a TLR2-dependent manner

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Cancer Communications 2024年第2期44卷 273-277页

作者： Mi-Jeong kim Ji young kim Ji Hye Shin Juhee Son Yeeun Kang Soo-kyung Jeong Duk-Hwan kim kyun-Hwan kim Eunyoung Chun Ki-young Lee Department of Immunology Samsung Biomedical Research InstituteSungkyunkwan University School of MedicineSuwonRepublic of Korea Research and Development Center CHA Vaccine InstituteSeongnam-siRepublic of Korea Department of Molecular Cell Biology Sungkyunkwan University School of MedicineSuwonRepublic of Korea Department of Precision Medicine Sungkyunkwan University School of MedicineSuwonRepublic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences&TechnologySamsung Medical CenterSungkyunkwan UniversitySeoulRepublic of Korea

Dear editor,Severe acute respiratory syndrome coronavirus2(SARS-CoV-2)infection can lead to severe outcomes in patients with cancer[1].It has been reported that patients with lung cancers disproportionately manifest severe COVID-19 with a high rate of hospitalization and death[2].Notably,the SARS-CoV-2 Spike(S)protein can induce hyper-inflammation in both epithelial cells and macrophages through toll-like receptor(TLR)1/TLR2 or TLR2/6-dependent nuclear factor-kappaB(NF-κB)path-way[3].However,molecular and cellular evidence on whether the SARS-CoV-2 virus affects the severity of lung cancer patients through TLR1/2 or TLR2/6 signaling remains unclear.

关键词： lung TLR2 invasion

Integration of earth-abundant cocatalysts for high-performance photoelectrochemical energy conversion

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Journal of Energy Chemistry 2024年第1期88卷 336-355,I0008页

作者： Joonhee Ma Sang Hyun Ahn Soo young kim Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea School of Chemical Engineering and Materials Science Chung-Ang University84 Heukseok-roDongjak-guSeoul 06974Republic of Korea

Photoelectrochemical(PEC)energy conversion has emerged as a promising and efficient approach to sustainable energy harvesting and *** utilizing semiconductor photoelectrodes,PEC devices can harness solar energy and drive electrochemical reactions such as water splitting or carbon dioxide(CO_(2))reduction to generate clean fuels and value-added ***,PEC energy conversion faces several challenges such as high overpotential,sluggish reaction kinetics,charge carrier recombination,and stability issues,which limit its practical ***,significant research has been conducted to improve the overall conversion efficiency of PEC *** particularly promising approach is the use of cocatalysts,which involves introducing specific cocatalysts onto the photoelectrode surface to promote charge separation,improve reaction kinetics,and reduce the overpotential,thereby enhancing the overall performance of PEC energy *** review provides a comprehensive overview of the recent developments in the earth-abundant cocatalysts for PEC water splitting and CO_(2) *** main earth-abundant catalysts for the PEC water splitting include transition-metal dichalcogenide(TMD)-based materials,metal phosphides/carbides,and metal oxides/***,PEC-CO_(2)RR was divided into C_(1) and C_(2+)based on the final product since various products could be produced,focusing on diverse earth-abundant materials-based *** addition,we provide and highlight key advancements achieved in the very recent reports on novel PEC system design engineering with ***,the current problems associated with PEC systems are discussed along with a suggested direction to overcome these obstacles.

关键词： Solar energy Photo-electrochemical Water splitting CO_(2)reduction Cocatalysts

On von Neumann Regularity of Commutators

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Algebra Colloquium 2024年第2期31卷 181-198页

作者： Nam kyun kim Tai Keun Kwak Yang Lee Sung Ju Ryu Nanqing Ding School of Basic Sciences Hanbat National UniversityDaejeon 34158Korea Department of Data Science Daejin UniversityPocheon 11159Korea Department of Mathematics Yanbian UniversityYanjiJilin 133002China Institute for Applied Mathematics and Optics Hanbat National University Daejeon 34158Korea Department of Mathematics Pusan National UniversityBusan 46241Korea 不详

We study the structure of rings which satisfy the von Neumann regularity of commutators,and call a ring R C-regularif ab-ba ∈(ab-ba)R(ab-ba)for all a,b in *** a C-regular ring R,we prove J(R[X])=N^(*)(R[X])=N^(*)(R)[X]=W(R)[X]■Z(R[X]),where J(A),N^(*)(A),W(A),Z(A)are the Jacobson radical,upper nilradical,Wedderburn radical,and center of a given ring A,respectively,and A[X]denotes the polynomial ring with a set X of commuting indeterminates over A;we also prove that R is semiprime if and only if the right(left)singular ideal of R is *** provide methods to construct C-regular rings which are neither commutative nor von Neumann regular,from any given ***,for a C-regular ring R,the following are proved to be equivalent:(i)R is Abelian;(ii)every prime factor ring of R is a duo domain;(ii)R is quasi-duo;and(iv)R/W(R)is reduced.

关键词： C-regular ring commutator regular ring commutative ring radical singular ideal

Tailoring Classical Conditioning Behavior in TiO_(2) Nanowires:ZnO QDs-Based Optoelectronic Memristors for Neuromorphic Hardware

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Nano-Micro Letters 2024年第7期16卷 265-280页

作者： Wenxiao Wang Yaqi Wang Feifei Yin Hongsen Niu young-Kee Shin Yang Li Eun-Seong kim Nam-young kim School of Information Science and Engineering University of JinanJinan 250022People’s Republic of China RFIC Centre NDAC CentreKwangwoon UniversityNowon-guSeoul 139-701South Korea Department of Electronics Engineering Kwangwoon UniversityNowon-GuSeoul 139-701South Korea School of Microelectronics Shandong UniversityJinan 250101People’s Republic of China Department of Molecular Medicine and Biopharmaceutical Sciences Seoul National UniversitySeoul 08826South Korea

Neuromorphic hardware equipped with associative learn-ing capabilities presents fascinating applications in the next generation of artificial ***,research into synaptic devices exhibiting complex associative learning behaviors is still ***,an optoelec-tronic memristor based on Ag/TiO_(2) Nanowires:ZnO Quantum dots/FTO was proposed and constructed to emulate the biological associative learning *** implementation of synaptic behaviors,including long and short-term plasticity,and learning-forgetting-relearning behaviors,were achieved in the device through the application of light and electrical *** the optoelectronic co-modulated characteristics,a simulation of neuromorphic computing was conducted,resulting in a handwriting digit recognition accuracy of 88.9%.Furthermore,a 3×7 memristor array was constructed,confirming its application in artificial visual *** importantly,complex biological associative learning behaviors were emulated by mapping the light and electrical stimuli into conditioned and unconditioned stimuli,*** training through associative pairs,reflexes could be triggered solely using light ***-sively,under specific optoelectronic signal applications,the four features of classical conditioning,namely acquisition,extinction,recovery,and generalization,were elegantly *** work provides an optoelectronic memristor with associative behavior capabilities,offering a pathway for advancing brain-machine interfaces,autonomous robots,and machine self-learning in the future.

关键词： Artificial intelligence Classical conditioning Neuromorphic computing Artificial visual memory Optoelectronic memristors ZnO Quantum dots

Hydrangea serrata extract exerts tumor inhibitory activity against hepatocellular carcinoma HepG2 cells via inducing p27/CDK2-mediated cell cycle arrest and apoptosis

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Asian Pacific Journal of Tropical Biomedicine 2024年第2期14卷 65-72,I0002-I0005页

作者： Ye-eun kim Jeonghye Hwang Ki-young kim Graduate School of Biotechnology Kyung Hee UniversitySeocheonGiheungYonginGyeonggi-do 446-701Republic of Korea Department of Genetics and Biotechnology College of Life SciencesKyung Hee UniversitySeocheonGiheungYonginGyeonggi-do 446-701Republic of Korea

Objective:To examine the inhibitory effect of Hydrangea serrata extract against hepatocellular carcinoma HepG2 cells and its underlying ***:The effects of Hydrangea serrata extract on growth inhibition of tumor cells and spheroids were assessed using MTT and 3D culture *** real-time PCR and Western blot analyses were employed to investigate the changes in mRNA and protein expression levels of molecules related to cell cycle and ***:Hydrangea serrata extract effectively inhibited the growth of both tumor cells and *** extract also significantly upregulated p27 mRNA expression and downregulated CDK2 mRNA expression,leading to cell cycle ***,increased BAX/Bcl-2 ratio as well as caspase-9 and-3 were observed after treatment with Hydrangea serrata extract,indicating the induction of tumor cell ***:Hydrangea serrata extract has the potential to alleviate tumors by effectively modulating cell-cycle-related gene expressions and inducing apoptosis,thereby inhibiting tumor growth.

关键词： Hydrangea serrata Hepatocellular carcinoma Liver cancer Anticancer Cell cycle arrest Apoptosis

MXene-based hybrid materials for electrochemical and photoelectrochemical H_(2) generation

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Journal of Energy Chemistry 2024年第6期93卷 111-125,I0004页

作者： Jun young kim Seung Hun Roh Chengkai Xia Uk Sim Jung Kyu kim School of Material Science and Engineering North University of ChinaTaiyuan 030051China School of Chemical Engineering Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea Hydrogen Energy Technology Laboratory Korea Institute of Energy Technology(KENTECH)NajuJeollanamdo 58330Republic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea

The conversion of solar energy to produce clean hydrogen fuel through water splitting is an emerging strategy for efficiently storing solar energy in the form of solar *** aligns with the increasing global demand for the development of an ideal energy alternative to fossil fuels that does not emit greenhouse ***(EC) and photoelectrochemical(PEC) water splitting technologies have garnered significant attention worldwide for advanced hydrogen solar fuel production in recent *** achieve sustainable green H_(2) production,it is essential to create efficient catalyst materials that are low-cost and can replace expensive noble metal-based *** characteristics make them an ideal catalyst material for the ***-dimensional MXenes with M_(n+1)X_(n) structure have been identified as a promising option for EC and PEC water splitting due to their superior hydrophilicity,metal-like conductivity,large surface area,and adjustable surface ***,we present a summary of recent advancements in the synthesis and performance enhancement methods for MXene hybrid materials in hydrogen production through EC and PEC water ***,we examine the challenges and insights associated with the rational design of MXene-based hybrid materials to facilitate efficient water splitting for sustainable solar fuel production.

关键词： MXene Hybrid materials EC PEC HER OER Water splitting