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Duo Property on the Monoid of Regular Elements

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Algebra Colloquium 2022年第2期29卷 203-216页

作者： Chan Yong Hong Hong Kee kim nam kyun kim Tai Keun Kwak Yang Lee Department of Mathematics Kyung Hee UniversitySeoul 02447Korea Department of Mathematics and RINS Gyeongsang National University Jinju 52828Korea School of Basic Sciences Hanbat National UniversityDaejeon 34158Korea Department of Mathematics Daejin UniversityPocheon 11159Korea Department of Mathematics Yanbian UniversityYanjiJilin 133002China Instituteof Basic Science Daejin UniversityPocheon 11159Korea

We study the right duo property on regular elements,and we say that rings with this property are right *** is first shown that the right duo property is preserved by right quotient rings when the given rings are right *** prove that thepolynomial ring over a ring R is right DR if and only if R is *** is also proved that for a prime number p,the group ring KG of a finite p-group G over a field K of characteristic p is right DR if and only if it is right duo,and that there exists a group ring KG that is neither DR nor duo when G is not a p-group.

关键词： right DR ring right duo ring quotient ring (skew)polynomial ring group ring

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

Incidence and Related Risk Factors of Junctional Ectopic Tachycardia in Infants after Cardiac Surgery for Congenital Heart Disease

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Congenital Heart Disease 2022年第5期17卷 569-578页

作者： Jae Hee Seol Se Yong Jung Jae Young Choi Han Ki Park Young Hwan Park nam kyun kim Department of Pediatrics Congenital Heart Disease CenterDivision of Pediatric CardiologySeverance Cardiovascular HospitalYonsei University College of MedicineSeoulKorea Department of Pediatrics Yonsei University Wonju College of MedicineWonjuKorea Department of Thoracic and Cardiovascular Surgery Division of Cardiovascular SurgeryCongenital Heart Disease CenterSeverance Cardiovascular HospitalYonsei University College of MedicineSeoulKorea Department of Pediatrics and Biomedical Engineering School of MedicineEmory UniversityAtlantaUSA

Objective:Junctional ectopic tachycardia is common after cardiac surgery for congenital heart ***,its incidence and related risk factors in infants after cardiac surgery are not well *** objective of this study was to determine the overall incidence and related risk factors for junctional ectopic tachycardia in neonates and ***:We enrolled a total of 271 patients aged<1 year who underwent open cardiac surgery at Severance Cardiovascular Hospital from January 2018 to December *** criteria were immediate postoperative mortality,other arrhythmias detected in the perioperative period,and ***:The overall incidence of junctional ectopic tachycardia was 12.9%.The logistic regression analysis revealed that longer cardiopulmonary bypass time,surgery involving atrioventricular node stretching,and the presence of early repolarization on preoperative electrocardiography increased the risk of junctional ectopic *** with junctional ectopic tachycardia had longer intubation time and intensive care unit ***:Junctional ectopic tachycardia is a common arrhythmia after cardiac surgery for congenital heart disease in ***,infants developing junctional ectopic tachycardia after cardiac surgery have specific preoperative electrocardiography *** risk factors for junctional ectopic tachycardia were associated not only with surgical procedural factors but also with preoperative electrocardiographic parameters.

关键词： Junctional ectopic tachycardia congenital heart disease early re-polarization

A Rapid Adaptation Approach for Dynamic Air‑Writing Recognition Using Wearable Wristbands with Self‑Supervised Contrastive Learning

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Nano-Micro Letters 2025年第2期17卷 417-431页

作者： Yunjian Guo Kunpeng Li Wei Yue nam‑Young kim Yang Li Guozhen Shen Jong‑Chul Lee Department of Electronic Convergence Engineering Kwangwoon UniversitySeoul 01897South Korea Radio Frequency Integrated Circuit(RFIC)Bio Centre Kwangwoon UniversitySeoul 01897South Korea Department of Electronic Engineering Kwangwoon UniversitySeoul 01897South Korea School of Microelectronics Shandong UniversityJinan 250101People’s Republic of China State Key Laboratory of Integrated Chips and Systems Fudan UniversityShanghai 200433People’s Republic of China School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081People’s Republic of China

Wearable wristband systems leverage deep learning to revolutionize hand gesture recognition in daily *** existing approaches that often focus on static gestures and require extensive labeled data,the proposed wearable wristband with selfsupervised contrastive learning excels at dynamic motion tracking and adapts rapidly across multiple *** features a four-channel sensing array composed of an ionic hydrogel with hierarchical microcone structures and ultrathin flexible electrodes,resulting in high-sensitivity capacitance *** wireless transmission from a Wi-Fi module,the proposed algorithm learns latent features from the unlabeled signals of random wrist ***,only few-shot labeled data are sufficient for fine-tuning the model,enabling rapid adaptation to various *** system achieves a high accuracy of 94.9%in different scenarios,including the prediction of eight-direction commands,and air-writing of all numbers and *** proposed method facilitates smooth transitions between multiple tasks without the need for modifying the structure or undergoing extensive task-specific *** utility has been further extended to enhance human–machine interaction over digital platforms,such as game controls,calculators,and three-language login systems,offering users a natural and intuitive way of communication.

关键词： Wearable wristband Self-supervised contrastive learning Dynamic gesture Air-writing Human-machine interaction

Prominent cycling reversibility and kinetics enabled by CaTiO3 protective layer on Zn metal for aqueous Zn-ion batteries

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Journal of Energy Chemistry 2025年第1期100卷 245-258页

作者： Gaeun Lee Yong nam Ahn Seongjoon So Chanwoo Park Jong-Seong Bae Taehyun Park Il Tae kim Jaehyun Hur School of Chemical Biological and Battery Engineering Gachon University Seongnam Busan Center Korea Basic Science Institute

Aqueous Zn-ion batteries （AZIBs） have received considerable attention owing to their various advantages such as safety,low cost,simple battery assembly conditions,and high ionic ***,they still suffer from serious problems,including uncontrollable dendrite growth,corrosion,hydrogen evolution reaction （HER） from water decomposition,electrode passivation,and unexpected *** creation of a uniform artificial nanocrystal layer on the Zn anode surface is a promising strategy for resolving these ***,we propose the use of a perovskite CaTiO3（CTO） protective layer on Zn（CTO@Zn） as a promising approach for improving the performance of *** CTO artificial layer provides an efficient pathway for Zn ion diffusion towards the Zn metal because of the high dielectric constant （εr=180） and ferroelectric characteristics that enable the alignment of dipole moments and redistribute the Zn2+ions in the CTO *** avoiding the direct contact of the Zn anode with the electrolyte solution,the uneven dendrite growth,corrosion,parasitic side reactions,and HER are mitigated,while CTO retains its mechanical and chemical robustness during ***,CTO@Zn demonstrates an improved lifespan in a symmetric cell configuration compared with bare ***@Zn shows steady overpotential （～68 m V） for 1500 h at 1 mA cm-2/0.5 mA h cm-2,excelling bare ***,when paired with the V2O5-C cathode,the CTO@Zn//V2O5-C full battery delivers 148.4 mA h g-1（based on the mass of the cathode） after 300 *** study provides new insights into Zn metal anodes and the development of high-performance AZIBs.

关键词： Perovskite

Stabilized sub-grain and nano carbides-driven 1.2 GPa grade ultra-strong CrMnFeCoNi high-entropy alloy additively manufactured by laser powder bed fusion

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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

Outlier Behavior Detection for Indoor Environment Based on t-SNE Clustering

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Computers, Materials & Continua 2021年第9期68卷 3725-3736页

作者： Shinjin Kang Soo kyun kim School of Games Hongik UniversitySejong30016Korea Department of Computer Engineering Jeju National UniversityJeju63243Korea

In this study,we propose a low-cost system that can detect the space outlier utilization of residents in an indoor *** focus on the users’app usage to analyze unusual behavior,especially in indoor *** is reflected in the behavioral analysis in that the frequency of using smartphones in personal spaces has recently *** system facilitates autonomous data collection from mobile app logs and Google app servers and generates a high-dimensional dataset that can detect outlier *** density-based spatial clustering of applications with noise(DBSCAN)algorithm was applied for effective singular movement *** analyze high-level mobile phone usage,the t-distributed stochastic neighbor embedding(t-SNE)algorithm was *** two clustering algorithms can effectively detect outlier behaviors in terms of movement and app usage in indoor *** experimental results showed that our system enables effective spatial behavioral analysis at a low cost when applied to logs collected in actual living ***,large volumes of data required for outlier detection can be easily *** system can automatically detect the unusual behavior of a user in an indoor *** particular,this study aims to reflect the recent trend of the increasing use of smartphones in indoor spaces to the behavioral analysis.

关键词： Outlier detection trajectory clustering behavior analysis app data smartphone