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Enhanced prediction of anisotropic deformation behavior using machine learning with data augmentation

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Journal of Magnesium and Alloys 2024年第1期12卷 186-196页

作者： Sujeong Byun Jinyeong Yu Seho Cheon seong ho Lee Sung Hyuk Park Taekyung Lee School of Mechanical Engineering Pusan National UniversityBusan 46241South Korea School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566South Korea

Mg alloys possess an inherent plastic anisotropy owing to the selective activation of deformation mechanisms depending on the loading *** characteristic results in a diverse range of flow curves that vary with a deformation *** study proposes a novel approach for accurately predicting an anisotropic deformation behavior of wrought Mg alloys using machine learning(ML)with data *** developed model combines four key strategies from data science:learning the entire flow curves,generative adversarial networks(GAN),algorithm-driven hyperparameter tuning,and gated recurrent unit(GRU)*** proposed model,namely GAN-aided GRU,was extensively evaluated for various predictive scenarios,such as interpolation,extrapolation,and a limited dataset *** model exhibited significant predictability and improved generalizability for estimating the anisotropic compressive behavior of ZK60 Mg alloys under 11 annealing conditions and for three loading *** GAN-aided GRU results were superior to those of previous ML models and constitutive *** superior performance was attributed to hyperparameter optimization,GAN-based data augmentation,and the inherent predictivity of the GRU for *** a first attempt to employ ML techniques other than artificial neural networks,this study proposes a novel perspective on predicting the anisotropic deformation behaviors of wrought Mg alloys.

关键词： Plastic anisotropy Compression Annealing Machine learning Data augmentation

Long cycle-life aqueous Zn battery enabled by facile carbon nanotube coating on Cu current collector

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Carbon Energy 2024年第6期6卷 151-164页

作者： Beom-Keun Cho Sung-ho Huh So Hee Kim Seungho Yu Jong-seong Bae Jung-Keun Yoo Seung-ho Yu Department of Chemical and Biological Engineering Korea UniversitySeoulRepublic of Korea Advanced Analysis Center Korea Institute of Science and Technology(KIST)SeoulRepublic of Korea Energy Storage Research Center Korea Institute of Science and Technology(KIST)SeoulRepublic of Korea KIST School Division of Energy and Environment TechnologyKorea University of Science and TechnologySeoulRepublic of Korea Busan Center Korea Basic Science Institute(KBSI)BusanRepublic of Korea Carbon Composites Department Composites Research DivisionKorea Institute of Materials Science(KIMS)ChangwonRepublic of Korea

As an alternative to Li-ion batteries,aqueous Zn batteries have gained attention due to the abundance of Zn metal,low reduction potential(-0.76 V *** hydrogen electrode),and high theoretical capacity(820 mAh g^(-1))of multivalent Zn2+***,the growth of Zn dendrites and the formation of irreversible surface reaction byproducts pose challenges for ensuring a long battery lifespan and ***,the Cu foil coated with a single-walled carbon nanotube(SWCNT)layer using a facile doctor blade casting method is *** SWCNT-coated Cu foil demonstrates a significantly longer battery lifespan compared to the bare Cu in the half-cell *** operando optical microscopy imaging,we are able to provide intuitive evidence that Zn deposition occurs between the carbon nanotube(CNT)coating and Cu substrate,in agreement with the computational ***,with various imaging techniques,the flat morphology and homogeneous distribution of Zn beneath the SWCNT layer are *** addition,the full-cell using CNT-coated Cu exhibits a long cycle life compared to the control group,thereby demonstrating improved electrochemical performance with limited Zn for the cycling process.

关键词： aqueous Zn battery carbon nanotube operando imaging surface coating

Correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

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Journal of Energy Chemistry 2024年第1期88卷 1-9,I0001页

作者： Inhyeok Cho Jiwon Yun Boseok seong Junseok Kim Sun Hee Choi ho-Il Ji Sihyuk Choi Department of Mechanical Engineering Kumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Department of Aeronautics Mechanical and Electronic Convergence EngineeringKumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea Center for Energy Materials Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Center for Hydrogen and Fuel Cell Research Clean Technology Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Department of Energy and Environmental Engineering University of Science and TechnologySeoul 02792Republic of Korea Nanomaterials Science and Engineering Korea University of Science and Technology(UST)KIST CampusSeoul 02792Republic of Korea

PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(PrBSCF) has attracted much research interest as a potential triple ionic and electronic conductor(TIEC) electrode for protonic ceramic fuel cells(PCFCs). The chemical formula for Pr BSCF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. Due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. Consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PCFC systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ)(LnBSCF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBSCF was 2.04 mol% and progressively decreased as the Ln cation size decreased. Similarly, the Gibbs free energy indicated that less energy was required for the formation of protonic defects in the order of Pr BSCF hodes, PCFC single cell measurements and analysis of the distribution of relaxation time were further investigated.

关键词： Protonic ceramic fuel cell Cathode Triple ionic and electronic conductor Hydration property Proton uptake Gibbs free energy

Atomically Adjustable Rhodium Catalyst Synthesis with Outstanding Mass Activity via Surface-Li mi ted Cation Exchange

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Energy & Environmental Materials 2024年第2期7卷 83-92页

作者： Hak Hyeon Lee Dong Su Kim Swagotom Sarker Ji hoon Choi ho seong Lee Hyung Koun Cho Department of Advanced Materials Science&Engineering Sungkyunkwan University2066Seobu-roJangan-guSuwon-siGyeonggi-doSeoul 16419Korea Department of Advanced Materials Science&Engineering Kyungpook National University80Daehak-roBuk-guDaegu 41566Korea

Rh has been widely studied as a catalyst for the promising hydrazine oxidation reaction that can replace oxygen evolution reactions for boosting hydrogen production from hydrazine-containing *** Rh being expensive,only a few studies have examined its electrocatalytic mass ***,surface-limited cation exchange and electrochemical activation processes are designed to remarkably enhance the mass activity of *** atoms were readily replaced at the Ni sites on the surface of NiOOH electrodes by cation exchange,and the resulting RhoOH compounds were activated by the electrochemical reduction *** cation exchange-derived Rh catalysts exhibited particle sizes not exceeding 2 nm without agglomeration,indicating a decrease in the number of inactive inner Rh ***,an improved mass activity of 30 A mg_(Rh)^(-1)was achieved at 0.4 V versus reversible hydrogen ***,the two-electrode system employing the same CE-derived Rh electrodes achieved overall hydrazine splitting over 36 h at a stable low *** proposed surface-limited CE process is an effective method for reducing inactive atoms of expensive noble metal catalysts.

关键词： cation exchange synthesis electrochemical metallization hydrazine oxidation reaction mass activity rhodium catalyst

Prevalence of nonalcoholic fatty liver disease in pediatrics and adolescents:a systematic review and meta-analysis

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World Journal of Pediatrics 2024年第6期20卷 569-580页

作者： Eun Joo Lee Miyoung Choi Sang Bong Ahn Jeong-Ju Yoo seong Hee Kang Yuri Cho Do Seon Song hong koh Dae Won Jeon Hye Won Lee Department of Pediatrics Yonsei University College of MedicineSeoulKorea Clinical Evidence Research National Evidence-Based Healthcare Collaborating Agency(NECA)SeoulKorea Department of Internal Medicine Nowon Eulji Medical CenterEulji University College of MedicineSeoulKorea Department of Internal Medicine Soonchunhyang University Bucheon HospitalBucheonKorea Department of Internal Medicine Sangkye Paek HospitalInje University College of MedicineSeoulKorea Center for Liver and Pancreatobiliary Cancer National Cancer CenterGoyangKorea Department of Internal Medicine College of MedicineSt.Vincent's HospitalThe Catholic University of KoreaSuwonKorea Department of Internal Medicine Hanyang University College of MedicineSeoulKorea Department of Internal Medicine Yonsei University College of MedicineSeoulKorea

Background As childhood obesity escalates worldwide,the prevalence of nonalcoholic fatty liver disease(NAFLD)in pediatric and adolescent populations is also ***,systematic studies and meta-analyses evaluating the prevalence of pediatric NAFLD remain *** The MEDLINE,Korean Medical Database(KMBASE),Embase,Global Health,and Cochrane Library databases were searched from January 1997 to April *** terms included NAFLD or steatosis;nonalcoholic or steatohepatitis;child(ren),adolescent,or teenager;and prevalence,incidence,or epidemiology.A random-effects meta-analysis model was used to estimate the prevalence of pediatric *** A total of 2116 publications were found,of which 62 were included in the *** them,27 reported the prevalence in the general population and 39 in the obese *** worldwide pooled prevalence of pediatric NAFLD was 13%[95%confidence interval(CI)9-18%]in the general population and 47%(95%CI 41%–53%)in the obese *** 16 studies in the general population and 18 in the obese population,NAFLD prevalence varied by *** the general population,the prevalence of NAFLD was 15%(95%CI 8%–23%)in males and 10%(95%CI 6%–15%)in *** the obese population,it was 54%(95%CI 46%–61%)in males and 39%(95%CI 30%–49%)in *** The global prevalence of pediatric NAFLD is rising in both the general and obese *** the increasing rates of childhood obesity,epidemiological studies on the prevalence and incidence of NAFLD are needed.

关键词： Meta-analysis Nonalcoholic fatty liver disease Pediatric Prevalence

Recent trends in the epidemiology and clinical outcomes of inflammatory bowel disease in South Korea,2010-2018

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World Journal of Gastroenterology 2024年第9期30卷 1154-1163页

作者： Seulji Kim Hyun Jung Lee Seung Woo Lee Sanghyun Park seong-Joon koh Jong Pil Im Byeong Gwan Kim Kyung-Do Han Joo Sung Kim Department of Internal Medicine Korea Institute of Radiological and Medical SciencesSeoul 01812South Korea Department of Internal Medicine and Liver Research Institute Seoul National University College of MedicineSeoul 03080South Korea Department of Statistics and Actuarial Science Soongsil UniversitySeoul 06978South Korea

BACKGROUND Inflammatory bowel disease(IBD)was previously regarded as a Western disease;however,its incidence is increasing in the *** epidemiology of IBD in Asia differs significantly from the patterns in the *** To comprehensively investigate the epidemiology of IBD in South Korea,inclu-ding its incidence,prevalence,medication trends,and *** We analyzed claims data from the Health Insurance Review and Assessment Service and Rare and Intractable Diseases(RIDs),operated by the National Health Insurance Service of South *** with IBD were identified based on the International Classification of Diseases,Tenth Revision,and RID diagnostic codes for Crohn’s disease(CD)and ulcerative colitis(UC)from 2010 to *** In total,14498 and 31409 patients were newly diagnosed with CD and UC,respectively,between 2010 and *** annual average incidence of CD was 3.11 cases per 105 person-years,and that of UC was 6.74 cases per 10^(5) *** 2014,the incidence rate of CD has been stable,while that of UC has steadily increased,shifting the peak age group from 50-year-olds in 2010 to 20-year-olds in *** CD and UC prevalence increased consistently over the study period;the use of 5-aminosali-cylates and corticosteroids gradually decreased,while that of immunomodulators and biologics steadily increased in both CD and *** clinical outcomes of IBD,such as hospitalization and surgery,decreased during the study *** The CD incidence has been stable since 2014,but that of UC has increased with a shift to a younger age at peak incidence between 2010 and *** clinical outcomes improved over time,with increased use of immunomodu-lators and biologics.

关键词： Inflammatory bowel disease Crohn’s disease Ulcerative colitis Incidence Prevalence

A new strain-based pentagonal membrane finite element for solid mechanics problems

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 211-216页

作者： Wei Hao koh Logah Perumal CheeKuang Kok Faculty of Engineering and Technology Multimedia UniversityMelaka 75450Malaysia

Polygonal finite elements remain an attractive option in finite element analysis due to their flexibility in modelingarbitrary shapes compared to *** this study,a pentagonal membrane element was developed with thestrain approach for the first *** element possesses invariance,and the equilibrium constraint was appliedto the assumed strain field using corrective *** by the advancing front technique,a pentagonalmesh was generated,and the mesh quality was enhanced with Laplacian *** performance of thedeveloped pentagonal element was assessed in a few numerical tests,and the results revealed its suitability inmodeling the bending of ***,the numerical results are enhanced when pentagonal elements are usedin mesh transitions along boundaries to smoothen curved edges and capture distributed loads.

关键词： Strain-based pentagonal element Corrective coefficients EquilibriumLaplacian smoothing Pentagonal mesh Mesh transition

Image enhancement with intensity transformation on embedding space

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CAAI Transactions on Intelligence Technology 2024年第1期9卷 101-115页

作者： Hanul Kim Yeji Jeon Yeong Jun koh Department of Applied Artificial Intelligence Seoul National University of Science and TechnologySeoulSouth Korea Department of Computer Science and Engineering Chungnam National UniversityDaejeonSouth Korea

In recent times,an image enhancement approach,which learns the global transformation function using deep neural networks,has gained ***,many existing methods based on this approach have a limitation:their transformation functions are too simple to imitate complex colour transformations between low-quality images and manually retouched high-quality *** order to address this limitation,a simple yet effective approach for image enhancement is *** proposed algorithm based on the channel-wise intensity transformation is ***,this transformation is applied to the learnt embedding space instead of specific colour spaces and then return enhanced features to *** this end,the authors define the continuous intensity transformation(CIT)to describe the mapping between input and output intensities on the embedding ***,the enhancement network is developed,which produces multi-scale feature maps from input images,derives the set of transformation functions,and performs the CIT to obtain enhanced *** experiments on the MIT-Adobe 5K dataset demonstrate that the authors’approach improves the performance of conventional intensity transforms on colour space ***,the authors achieved a 3.8%improvement in peak signal-to-noise ratio,a 1.8%improvement in structual similarity index measure,and a 27.5%improvement in learned perceptual image patch ***,the authors’algorithm outperforms state-of-the-art alternatives on three image enhancement datasets:MIT-Adobe 5K,Low-Light,and Google HDRþ.

关键词： computer vision deep learning image enhancement image processing

Tracking of horizontal alignment of the long and large diameter uncharged hole in NATM tunnel

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Underground Space 2024年第3期16卷 18-28页

作者： Min-seong Kim Sean Seungwon Lee Department of Energy and Resources Engineering Chonnam National UniversityGwangju 61186Republic of Korea Department of Earth Resources and Environmental Engineering Hanyang UniversitySeoul 04763Republic of Korea

The long and large diameter uncharged hole boring(LLB)method is a cut blasting method that minimizes blast-induced vibrations by creating long and large diameter uncharged holes at the excavation face of tunnels prior to tunnel *** in this method typically uses a 50 m long with a 382 mm diameter hammer bit in the horizontal direction at the tunnel ***,the significant weight and uni-directional rotation of the rod head,as well as variables such as geological characteristics,machine conditions,and inexperienced operators result in significant deviation from the target borehole alignment that hinders the vibration-dampening effect of the uncharged ***,since there is no method to verify the alignment of the boreholes until main tunnel construction,borehole misalignment is often not discovered until weeks after construction,which requires tunnel construction to cease until the equipment can be remobilized and an additional borehole be created,causing significant delays and increased costs for the entire tunnel *** this study,the borehole alignment tracking and ground exploration system(BGS)is developed to predict and monitor the quality and alignment of boreholes for cut blasting methods such as the LLB methods immediately after *** BGS was subsequently tested at a subway construction site to evaluate its performance in the *** measurements yielded by the BGS were compared with manually measured boring positions at every 5 m along the *** the BGS showed a maximum deviation of approximately 12%at a local point where the hole surface was relatively rough,the accuracy for the final boring position was approximately 97%,demonstrating excellent precision of the alignment tracking *** BGS demonstrates excellent performance in predicting ground conditions and the boring quality of a cut hole immediately after drilling,and shows promise in various other applications for monitoring borehole alignment.

关键词： Tunnel blasting LLB method Drilling deviation Vertical sagging horizontal alignment tracking BGS