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Predictive modeling of critical temperatures in magnesium compounds using transfer learning

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Journal of Magnesium and Alloys 2024年第4期12卷 1540-1553页

作者： Surjeet Kumar Russlan Jaafreh Subhajit Dutta Jung Hyeon Yoo Santiago Pereznieto Kotiba Hamad dae ho yoon School of Advanced Materials Science&Engineering Sungkyunkwan University Suwon 16419Republic of Korea

This study presents a transfer learning approach for discovering potential Mg-based superconductors utilizing a comprehensive target ***,a large source dataset(Bandgap dataset)comprising approximately∼75k compounds is utilized for pretraining,followed by fine-tuning with a smaller Critical Temperature(T_(c))dataset containing∼300 ***,there is a significant improvement in the performance of the transfer learning model over the traditional deep learning(DL)model in predicting ***,the transfer learning model is applied to predict the properties of approximately 150k *** are validated computationally using density functional theory(DFT)calculations based on lattice dynamics-related ***,to demonstrate the extended predictive capability of the transfer learning model for new materials,a pool of virtual compounds derived from prototype crystal structures from the Materials Project(MP)database is generated.T_(c) predictions are obtained for∼3600 virtual compounds,which underwent screening for electroneutrality and thermodynamic *** Extra Trees-based model is trained to utilize E_(hull)values to obtain thermodynamically stable materials,employing a dataset containing Ehull values for approximately 150k materials for *** with Ehull values exceeding 5 meV/atom were filtered out,resulting in a refined list of potential Mg-based *** study showcases the effectiveness of transfer learning in predicting superconducting properties and highlights its potential for accelerating the discovery of Mg-based materials in the field of superconductivity.

关键词： Superconductivity Critical temperature Transfer learning Crystal structure features Thermodynamic stability

Growth and Magnetic Properties of Sol-Gel Derived Co-Doped ZnO Thin Film

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Journal of Rare Earths 2006年第Z1期24卷 59-63页

作者： Young Sung Kim Ki Chul Kim Won Pil Tae dae ho yoon Tae Seok Park Su Jeong Suh Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea Cambridge-ETRI Joint R&D Centre Electronics and Telecommunications Research Institute Daejeon 305-350 Korea Ulsan Industry Promotion Techno Park Ulsan 683-804 Korea Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea Advanced Material Process of Information Technology Sungkyunkwan University Suwon 440-746 Korea

Zn1-xCoxO films were grown on glass by sol-gel spin coating process. A homogeneous and stable Zn1-xCoxO sol was prepared by dissolving zinc acetate dihydrate, cobalt acetate tetrahydrate and aluminium chloride hexahydrate as solutes in solution of isopropanol and monoethanolamine. The films were postheated and vacuum annealed, and investigated for c-axis preferred orientation and electromagnetic properties. Zn1-xCoxO films with different Co concentrations were oriented well along the c-axis, especially the Zn1-xCoxO film with 10% Co(atom fraction) was highly c-axis oriented. The transmittance spectra show that Zn1-xCoxO films occur d-d transition and sp-d exchange interaction between Co2+ ions. The electrical resistivity of the films at 10% Co had the lowest value because the crystallite size became largest and the crystallinity of the c-axis was improved. X-ray photoelectron spectroscopy and alternating gradient magnetometer analyses indicated that no Co metal cluster was formed, and the ferromagnetism at room temperature appeared. The characteristics of the electrical resistivity and room temperature ferromagnetism of sol-gel derived Zn1-xCoxO films suggest a potential application of dilute magnetic semiconductor devices.

关键词： sol-gel Zn1-xCoxO thin film dilute magnetic semiconductor (DMS)

Trifunctional robust electrocatalysts based on 3D Fe/N-doped carbon nanocubes encapsulating Co4N nanoparticles for efficient battery-powered water electrolyzers

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Carbon Energy 2024年第6期6卷 124-139页

作者： Hyung Wook Choi hongdae Lee Jun Lu Seok Bin Kwon Dong In Jeong Beum Jin Park Jiwon Kim Bong Kyun Kang Gun Jang dae ho yoon ho Seok Park SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea School of Chemical Engineering Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea Department of Electronic Materials Devicesand Equipment EngineeringSoonchunhyang UniversityAsan CityChungnamRepublic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwon-siGyeonggi-doRepublic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan UniversitySuwonRepublic of Korea

Herein,we have designed a highly active and robust trifunctional electrocatalyst derived from Prussian blue analogs,where Co_(4)N nanoparticles are encapsulated by Fe embedded in N-doped carbon nanocubes to synthesize hierarchically structured Co_(4)N@Fe/N-C for rechargeable zinc-air batteries and overall water-splitting *** confirmed by theoretical and experimental results,the high intrinsic oxygen reduction reaction,oxygen evolution reaction,and hydrogen evolution reaction activities of Co_(4)N@Fe/N-C were attributed to the formation of the heterointerface and the modulated local electronic ***,Co_(4)N@Fe/N-C induced improvement in these trifunctional electrocatalytic activities owing to the hierarchical hollow nanocube structure,uniform distribution of Co_(4)N,and conductive encapsulation by Fe/***,the rechargeable zinc-air battery with Co_(4)N@Fe/N-C delivers a high specific capacity of 789.9 mAh g^(-1) and stable voltage profiles over 500 ***,the overall water electrolyzer with Co_(4)N@Fe/N-C achieved better durability and rate performance than that with the Pt/C and IrO2 catalysts,delivering a high Faradaic efficiency of 96.4%.Along with the great potential of the integrated water electrolyzer powered by a zinc-air battery for practical applications,therefore,the mechanistic understanding and active site identification provide valuable insights into the rational design of advanced multifunctional electrocatalysts for energy storage and conversion.

关键词： battery-powered electrolyzers hierarchical structure Prussian blue analog trifunctional electrocatalyst zinc-air battery

Investigation of Domain Wall Velocity to External Fields for High-Quality Waveguide-Type Periodically Poled LiNbO_(3) Fabrication

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Journal of Rare Earths 2006年第Z1期24卷 131-135页

作者： Soo Woo Kwon Woo Seok Yang H M Lee Woo Kyung Kim Hang Yong Lee dae ho yoon Yo Seung Song Department of Materials Engineering Hankuk Aviation UniversityGoyang 412-791Korea Nano Bio-Photonics Team Korea Electronics Technology InstituteBundang 463-816Korea Department of Advanced Material Engineering Sungkyunkwan UniversitySuwon 440-746Korea

The Ti-doped waveguide-type periodically poled LiNbO_(3)(PPLN)were fabricated and the dependence of domain wall velocity on an external field applied for domain inversion was *** whole polarization reversal process was computer-controlled to regulate domain wall expansion at a feedback time shorter than 5μ*** coercive voltage and several values of excess voltage were applied on 500μm-thick wafers serially connected to a 1-MOhm external resistor which had an effect of the poling current reduction,*** deceleration of domain wall *** domain wall velocity is sensitive to the poling voltage,precisely speaking,to the excess *** domain wall velocities were 28.70,16.02 and 5.75μm·s^(-1)under poling field of 23.5,22.0 and 21.0 kV·mm^(-1),***,average duty cycle of PPLN is about 49.93%.

关键词： periodically poled lithium niobate coerciv field duty cycle domain wall velocity quasi phase matching

In-situ formation of MOF derived mesoporous Co3N/amorphous N-doped carbon nanocubes as an efficient electrocatalytic oxygen evolution reaction

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Nano Research 2019年第7期12卷 1605-1611页

作者： Bong Kyun Kang Seo Young Im Jooyoung Lee Sung hoon Kwag Seok Bin Kwon SintayehuNibret Tiruneh Min-Jun Kim Jung ho Kim Woo Seok Yang Byungkwon Lim dae ho yoon Nano Materials and Components Research Center Korea Electronics Technology InstituteSeongnam 463-816Republic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan University Suwon 440-746Republic of Korea Advanced Materials & Processing Center Institute for Advanced Engineering (IAE)Yongin 175-28Republic of Korea Australian Institute for Innovative Materials (AIIM) University of WollongongSquires WayNorth Wollongong NSW 2500Australia Department of Advanced Materials Engineering for Information and Electronics Kyung Hee University1732 Deogyeong-daeroGiheung-guYongin-siGyeonggi-do17104Republic of Korea

The suitable materials,metal nitrides,are a promising class of electrocatalyst materials for a highly efficient oxygen evolution reaction (OER) because they exhibit superior intrinsic conductivity and have higher sustainability than oxide-based *** our knowledge,for the first time,we report a designable synthesis of three-dimensional (3D) and mesoporous Co3N@ amorphous N-doped carbon (AN-C) nanocubes (NCs) with well-controlled open-framework structures via monodispersed Co3[Co(CN)6]2 Prussian blue analogue (PBA) NC precursors using in situ nitridation and calcination ***3N@AN-C NCs (2 h) demonstrate better OER activity with a remarkably low Tafel plot (69.6 mV-dec-1),low overpotential of 280 mV at a current density of 10 ***,excellent cycling stability in alkaline electrolytes was exhibited without morphological changes and voltage elevations,superior to most reported hierarchical structures of transition-metal nitride *** presented strategy for synergy effects of metal-organic frameworks (MOFs)-derived transition-metal nitrides-carbon hybrid nanostructures provides prospects for developing high-performance and advanced electrocatalyst materials.

关键词： transition-metal nitride metal organic framework mesoporous oxygen evaluation reaction alkaline water electrolysis

Food intolerance and skin prick test in treated and untreated irritable bowel syndrome

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World Journal of Gastroenterology 2006年第15期12卷 2382-2387页

作者： dae-Won Jun Oh-Young Lee ho-Joo yoon Seok-Hwa Lee Hang-Lak Lee ho-Soon Choi Byung-Chul yoon Min-ho Lee Dong-hoo Lee Sang-hoen Cho Department of Internal Medicine College of Medicine Hanyang UniversitySeoulKorea Department of Food and Nutrition College of Human Ecology Hanyang UniversitySeoulKorea Department of Internal Medicine College of Medicine Seoul National UniversitySeoulSouth Korea

AIM： To correlate the clinical features of treated and untreated patients with irritable bowel syndrome （IBS） to the results of skin prick test （SPT） for food and inhalant allergens. METhoDS： We recruited 105 subjects to form three different target groups： treated group （n=44） undergoing treatment for IBS, untreated group （n =31） meeting the Rome Ⅱ criteria without treatment for IBS, control group （n = 30） with no IBS symptoms. RESULTS： SPT results were different among the three groups in which SPT was positive in 17 （38.6%） treated patients, in 5 （16.1%） untreated patients and in 1 （3.3%） control （P〈0.01）. The number of positive SPTs was greater in the IBS group than in the control group （P〈 0.001）. The number of positive food SPTs was higher in the treated IBS group than in the untreated IBS group （P= 0.03）. CONCLUSION： Positive food SPT is higher in IBS patients than in controls.

关键词： Irritable bowel syndrome Skin prick test Food allergy

Evaluation of the performance of a soft X-ray charger for the bipolar charging of nanoparticles

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Particuology 2015年第1期13卷 165-169页

作者： Young Hun yoon Choonkeun Bong dae Seong Kim Department of Integrated Environmental Systems Pyeongtaek University GreenSolus Co. Global Frontier Center for Multiscale Energy Systems Seoul National University

The use of soft X-rays in a neutralizer represents an alternative technique that could replace conventional radioactive sources. In this study, we evaluated the charging characteristics of a soft X-ray aerosol neu- tralizer. In addition, the results from the evaluation of the soft X-ray charger were compared with results obtained using a neutralizer incorporating an 241 Am radioactive source. The tandem differential mobility analyzer technique was used previously to determine the size-dependent positive, negative, and neutral charge fractions of a soft X-ray neutralizer. This technique was used to show that the neutral fractions obtained using the soft X-ray charger agreed well with the predictions of bipolar diffusion charging the- ory, and that the soft X-ray charger could be used as a neutralizer for a scanning mobility particle sizer system.

关键词： Soft X-ray Neutralizer Bipolar charger Nanoparticle TDMA

A macroscopic constitutive model of shape memory alloy considering cyclic effects

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Science China(Physics,Mechanics & Astronomy) 2013年第4期56卷 755-764页

作者： ZhoU Bo yoon Sung-ho College of Pipeline and Civil Engineering China University of Petroleum School of Mechanical Engineering Kumoh National Institute of Technology

This paper presents a macroscopic constitutive model reproducing the hysteretic behaviors of the superelastic shape memory alloy (SMA) under cyclic loading. The progressive increase of residual strain with the increased cycle number in such materials is assumed to be a consequence of the progressive increase of residual stress-induced martensitic volume fraction upon the cyclic effects. The progressive decrease of phase transformation critical stresses with the increased cycle number in such materials is assumed to be a result from the progressive increase of phase transformation critical temperatures upon the cyclic effects. A cyclic evolution equation is supposed to describe the influences of cycle effects on the material properties of the SMA under cyclic loading. A phase transformation equation expressing the phase transformation behaviors of the SMA under cyclic loading is established based on the differential relationship between martensitic volume fraction and the free energy increment of phase transformation. A mechanical constitutive equation predicting the mechanical characteristics of the SMA under cyclic loading is developed on the basis of thermodynamics and continuum mechanics. The cyclic evolution equation, phase transformation equation, and mechanical constitutive equation together compose the presented macroscopic constitutive model considering cyclic effects. Results of the numerical simulations illustrate that it can well reproduce the superelastic hysteretic behaviors of the SMA under cyclic loading.

关键词： shape memory alloy cyclic effect cyclic evolution equation phase transformation equation mechanical constitutive equation

Optimization of post-warranty sequential inspection for second-hand products

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Journal of Systems Engineering and Electronics 2017年第4期28卷 793-800页

作者： dae-Kyung Kim Jae-Hak Lim Dong ho Park Department of Statistics Chonbuk National University Department of Management & Accounting Hanbat National University Industry Academic Cooperation Foundation Hallym University

This paper considers an optimal sequential inspection schedule for a second-hand product after that the free nonrenewable warranty is expired. The length of warranty is prespecified and during the warranty period, the product is minimally repaired by the dealer when it fails. Following the expiration of the non-renewing warranty, the product is inspected and upgraded sequentially a fixed number of times at the expenses of the *** each inspection, the failure rate of the product is reduced proportionally so that the product is upgraded. The product is assumed to deteriorate as it ages and the replacement of the product occurs when a fixed number of inspections are rendered. In addition,the intervals between two successive inspections are assumed to decrease monotonically. The main objective of this paper is to determine the optimal improvement level to upgrade the product at each inspection so that the expected maintenance cost during the life cycle of the product is minimized from the perspective of the customer. Under the given cost structures, we derive an explicit formula to obtain the expected maintenance cost incurred during the life cycle of the product and discuss the method to find the optimal level of the improvement analytically in case the failure times follow the Weibull distribution. Numerical results are analyzed to observe the impact of relevant parameters on the optimal solution.

关键词： second-hand product sequential inspection upgrade action life cycle of the product expected maintenance cost free non-renewable warranty