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Carbon Energy 2024年第3期6卷 36-52页

作者： Dae-Ho son Ha Kyung Park Dae-Hwan Kim Jin-Kyu Kang Shi-joon Sung Dae-Kue Hwang Jaebaek Lee Dong-Hwan Jeon Yunae Cho William Jo Taeseon Lee JunHo Kim Sang-Hoon Nam Kee-Jeong Yang Division of Energy Technology DGISTDaeguRepublic of Korea Research Center for Thin Film Solar Cells DGISTDaeguRepublic of Korea Department of Physics Ewha Womans UniversitySeoulRepublic of Korea Department of Physics Incheon National UniversityIncheonRepublic of Korea Department of Mechanical Engineering Massachusetts Institute of TechnologyCambridgeMassachusettsUSA

Cu2ZnSn(S,Se)4(CZTSSe)solar cells have resource distribution and economic *** main cause of their low efficiency is carrier loss resulting from recombination of photo-generated electron and *** overcome this,it is important to understand their electron-hole behavior *** determine the carrier separation characteristics,we measured the surface potential and the local current in terms of the absorber *** elemental variation in the intragrains(IGs)and at the grain boundaries(GBs)caused a band edge shift and bandgap(Eg)*** the absorber surface and subsurface,an upward Ec and Ev band bending structure was observed at the GBs,and the carrier separation was *** the absorber center,both upward Ec and Ev and downward Ec-upward Ev band bending structures were observed at the GBs,and the carrier separation was *** improve the carrier separation and suppress carrier recombination,an upward Ec and Ev band bending structure at the GBs is desirable.

关键词： carrier separation CZTSSe flexible solar cell local current surface potential

A Study on the Optimal Offset Distance Between a Welding Torch and the Infrared Thermometers

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Fluid Dynamics & Materials Processing 2019年第1期15卷 1-14页

作者： Tae-Jong Yun Won-Bin Oh Bo-Ram Lee joon-sik son Ill-soo Kim Department of Mechanical Engineering Mokpo National University1666 Yeongsan-roCheonggyemyeonMuan-gunJeollanam-do58554South Korea Research Institute of Medium&Small Shipbuilding 55Daebuljugeo 3-roSamho-eupYeongam-gunJeollanam-do58457South Korea

Detection of weld defects using real-time monitoring and controlling algorithm is of the significant task in manufacturing industries due to the increased production and liability costs that result when weld defects are not identified early in the production *** and controlling for robotic arc welding process employed should be reliable,flexible and cost-effective in non-clean,high-volume production ***,the robotic welding system has been utilized a complex jigging and mechanical devices to move the workpiece which related to the stationary welding head for getting higher efficiency and lower *** develop the fully robotic welding system,people make use of their senses of sound and/or sight to collect welding information,and take the necessary corrective measurements to ensure the weld quality after processing is ***,it is really required that the monitoring and controlling algorithm of sensors for increasing effectiveness in the robotic welding process has been *** this paper,bead-on-plate welding using an infrared thermography in the robotic GMA(Gas Metal Arc)welding process has been performed to study the effects of welding parameters on thermal profile characteristics and find the optimal offset distance which applied for monitoring and controlling of welding quality such as bead *** analysis for correlation between temperature distributions at three offset distance and bead height which based on the regression analysis such as Standard Error of Estimate(SEE),the coefficient of correlation(R)and coefficient of determination(R2)and(Predictive Ability of Model)has been *** infra-red sensor is useful for monitoring the isotherm radii that arise during the robotic welding process and identifying bead height as welding quality.

关键词： GMA welding adaptive control bead-on-plate joint infrared thermometers bead height

Task scheduling scheme by checkpoint sharing and task duplication in P2P-based desktop grids

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Journal of Central South University 2014年第10期21卷 3864-3872页

作者： joon-Min Gil Young-sik Jeong School of IT Engineering Catholic University of Daegu13-13Hayang-ro Hayang-eup Gyeongsan-si Gyeongbuk 712-701 Korea Department of Multimedia Engineering Dongguk University 30 Pildong-rol-gilJung-gu Seoul 100-715 Korea

A scheduling scheme is proposed to reduce execution time by means of both checkpoint sharing and task duplication under a peer-to-peer(P2P) architecture. In the scheme, the checkpoint executed by each peer(i.e., a resource) is used as an intermediate result and executed in other peers via its duplication and transmission. As the checkpoint is close to a final result, the reduction of execution time for each task becomes higher, leading to reducing turnaround time. To evaluate the performance of our scheduling scheme in terms of transmission cost and execution time, an analytical model with an embedded Markov chain is presented. We also conduct simulations with a failure rate of tasks and compare the performance of our scheduling scheme with that of the existing scheme based on client-server architecture. Performance results show that our scheduling scheme is superior to the existing scheme with respect to the reduction of execution time and turnaround time.

关键词： P2P-based desktop grids checkpoint sharing task duplication embedded Markov chain

Soil compression influences the avoidance behavior of Allonychiurus kimi(Collembola)to cadmium and copper

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Pedosphere 2022年第3期32卷 487-494页

作者： Jino son Yun-sik LEE Yongeun KIM Kijong CHO OJeong Eco-Resilience Institute Korea UniversitySeoul 02841(Republic of Korea) Department of Environmental Science and Ecological Engineering Korea UniversitySeoul 02841(Republic of Korea) Institute of Environment and Ecology Korea UniversitySeoul 02841(Republic of Korea)

The behavior of soil organisms inhabiting soil pore spaces can be influenced by soil compression,which can affect their avoidance behavior to *** this study,we aimed to evaluate the effect of soil compression on the avoidance behavior of Allonychiurus kimi(Collembola)to heavy metals cadmium and ***,to assess the applicability of the avoidance test guideline of the International Organization for Standardization(ISO)developed for Folsomia candida,we investigated the avoidance behavior of *** to cadmium and copper in an artificial soil with a loose structure(bulk density of 0.25 g cm^(-3)),the porous texture of which was sufficiently loose to enable *** to move between pore *** effect of soil compression on the avoidance behavior of *** to both metals was evaluated in compressed soil(bulk density of 0.64 g cm^(-3))with a uniformly compressed soil surface,and avoidance behavior was investigated at 24-h intervals over a 120-h *** that *** is unable to burrow into compressed soil,the compressed soil test can minimize the effects of differences in soil factors,such as soil porosity and bulk density,on the behavior of this *** the artificial soil,a statistically significant avoidance behavior of *** was observed at cadmium and copper concentrations greater than 50 and 200 mg kg^(-1),respectively,thereby indicating the applicability of the ISO avoidance test guidelines for *** compared at the same exposure time point,the avoidance response to both metals in compressed soil was less sensitive than that in uncompressed *** addition,we observed differences in the effects of metals on avoidance response in the compressed soil over time,with the effect of cadmium increasing with time and the effect of copper showing the opposite ***,we found that soil compression can affect the avoidance behavior of *** to cadmium and copper,and we discussed the advantages and limitations of using compressed

关键词： behavioral endpoint ecotoxicity test habitat function heavy metal pollutant springtail

Exploiting the quantum mechanically derived force field for functional materials simulations

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npj Computational Materials 2021年第1期7卷 1405-1413页

作者： Alexey Odinokov Alexander Yakubovich Won-joon son Yongsik Jung Hyeonho Choi Samsung R&D Institute Russia(SRR) Samsung Electronics12 Dvintsev StreetMoscow 127018Russia Data and Information Technology Center Samsung ElectronicsHwaseong 18448Korea Samsung Advanced Institute of Technology(SAIT) Samsung Electronics130 Samsung-roYeongtong-guSuwon 16678Korea

The computational design of functional materials relies heavily on large-scale atomistic *** simulations are often problematic for conventional classical force fields,which require tedious and time-consuming parameterization of interaction *** problem can be solved using a quantum mechanically derived force field(QMDFF)—a system-specific force field derived directly from the first-principles *** present a computational approach for atomistic simulations of complex molecular systems,which include the treatment of chemical reactions with the empirical valence bond *** accuracy of the QMDFF is verified by comparison with the experimental properties of liquid *** illustrate the capabilities of our methodology to simulate functional materials in several case studies:chemical degradation of material in organic light-emitting diode(OLED),polymer chain packing,material morphology of organometallic *** presented methodology is fast,accurate,and highly automated,which allows its application in diverse areas of materials science.

关键词： functional field quantum

Simultaneous surface modification method for 0.4Li2MnO3-0.6LiNi1/3Co1/3Mn1/3O2 cathode material for lithium ion batteries： Acid treatment and LiCoPO4 coating

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Nano Research 2017年第12期10卷 4210-4220页

作者： Min-joon Lee Eunsol Lho Pilgun Oh Yoonkook son Jaephil Cho Department of Energy Engineering School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST) Ulsan 44919 Republic of Korea

Li-rich layered cathode materials have been considered the most promising candidates for large-scale Li-ion batteries due to their low cost and high reversible capacity. However, these materials have many drawbacks that hinder commercialization, such as low initial efficiency and cyclability at elevated temperatures. To overcome these barriers, we propose an efficient and effective surface modification method, in which chemical activation （acid treatment） and LiCoPO4 coating were carried out simultaneously. During the synthesis, the lithium ions were extracted from the lattice, leading to improved Columbic efficiency, and these ions were used for the formation of LiCoPO4. The Ni and Co doped spinel phase was formed at the surface of the host material, which gives rise to the facile pathway for lithium ions. The LiCoPO4 and highly doped spinel on the surface acted as double protection layers that effectively prevented side reactions on the surface at 60℃. Moreover, the transition metal migration of the modified cathode was weakened, due to the presence of the spinel structure at the surface. Consequently, the newly developed Li-rich cathode material exhibited a high 1st efficiency of 94%, improved capacity retention of 82% during 100 cycles at 60℃, and superior rate capability of 62% at 12C （1C = 200 mA/g） rate at 24℃. In addition, the thermal stability of the modified cathode was significantly improved as compared to that of a bare counterpart at 4.6 V, showing a 60% decrease in the total heat generation.

关键词： lithium ion battery cathode material Li-rich material electrochemistry surface modification

Effect of equal-channel angular pressing on pitting corrosion resistance of anodized aluminum-copper alloy

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中国有色金属学会会刊：英文版 2009年第4期19卷 904-908页

作者： In-joon son Hiroaki NAKANO Satoshi OUE Shigeo KOBAYASHI Hisaaki FUKUSHIMA Zenji HORITA Department of Materials Process Engineering Graduate School of EngineeringKyushu University Department of Materials Science and Engineering Faculty of EngineeringKyushu University Department of Applied Chemistry and Biochemistry Faculty of EngineeringKyushu Sangyo University

The effect of equal-channel angular pressing(ECAP) on the pitting corrosion resistance of anodized Al-Cu alloy was investigated by electrochemical techniques in a solution containing 0.2 mol/L AlCl3 and also by surface *** was conducted for 20 min at 200 and 400 A/m2 in a solution containing 1.53 mol/L H2SO4 and 0.018 5 mol/L Al2(SO4)3·16H2O at 20 ℃.Anodized Al-Cu alloy was immediately dipped in boiling water for 20 min to seal the micro pores present in anodic oxide *** time required before initiating pitting corrosion of anodized Al-Cu alloy is longer with ECAP than without,indicating that ECAP process improves the pitting corrosion resistance of anodized Al-Cu *** phase precipitates such as Si,Al-Cu-Mg and Al-Cu-Si-Fe-Mn intermetallic compounds are present in Al-Cu alloy and the size of these precipitates is greatly decreased by application of ***-Cu-Mg intermetallic compounds are dissolved during anodization,whereas the precipitates composed of Si and Al-Cu-Si-Fe-Mn remain in anodic oxide films due to their more noble corrosion potential than ***-SEM and EPMA observation reveal that the pitting corrosion of anodized Al-Cu alloy occurs preferentially around Al-Cu-Si-Fe-Mn intermetallic compounds,since the anodic oxide films are absent at the boundary between the normal oxide films and these impurity *** improvement of pitting corrosion resistance of anodized Al-Cu alloy processed by ECAP appears to be attributed to a decrease in the size of precipitates,which act as origins of pitting corrosion.

关键词：铝铜合金抗点蚀挤压转角通道

Nanoconfinement effect of nanoporous carbon electrodes for ionic liquid-based aluminum metal anode

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Journal of Energy Chemistry 2022年第11期31卷 121-127,I0005页

作者： Juhee Yoon Seongbak Moon son Ha Hyung-Kyu Lim Hyoung-joon Jin Young Soo Yun Program in Environmental and Polymer Engineering Inha UniversityIncheon 22212South Korea Department of Polymer Science and Engineering Inha UniversityIncheon 22212South Korea KU-KIST Graduate School of Converging Science and Technology Korea UniversitySeoul 02841South Korea Division of Chemical Engineering and Bioengineering Kangwon National UniversityGangwon-do 24341South Korea Department of Integrative Energy Engineering Korea UniversitySeoul 02841South Korea

Rechargeable aluminum batteries(RABs),which use earth-abundant and high-volumetric-capacity metal anodes(8040 m Ah cm-3),have great potential as next-generation power sources because they use cheaper resources to deliver higher energies,compared to current lithium ion ***,the mechanism of charge delivery in the newly developed,ionic liquid-based electrolytic system for RABs differs from that in conventional organic ***,targeted research efforts are required to address the large overpotentials and cycling decay encountered in the ionic liquid-based electrolytic *** this study,a nanoporous carbon(NPC)electrode with well-developed nanopores is used to develop a high-performance aluminum *** negatively charged nanopores can provide quenched dynamics of electrolyte molecules in the aluminum deposition process,resulting in an increased collision *** fast chemical equilibrium of anionic species induced by the facilitated anionic collisions leads to more favorable reduction reactions that form aluminum *** nanoconfinement effect causes separated nucleation and growth of aluminum nanoparticles in the multiple confined nanopores,leading to higher coulombic efficiencies and more stable cycling performance compared with macroporous carbon black and 2D stainless steel electrodes.

关键词： Nanoconfinement effect Nanoporous carbon Ionic liquid electrolyte Metal anode Aluminum batteries Multivalent batteries

Estimating the instantaneous reproduction number(R_(t))by using particle filter

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Infectious Disease Modelling 2023年第4期8卷 1002-1014页

作者： Yong Sul Won Woo-sik son Sunhwa Choi Jong-Hoon Kim National Institute for Mathematical Sciences DaejeonSouth Korea International Vaccine Institute SeoulSouth Korea

Background:Monitoring the transmission of coronavirus disease 2019(COVID-19)requires accurate estimation of the effective reproduction number(Rt).However,existing methods for calculating Rt may yield biased estimates if important real-world factors,such as delays in confirmation,pre-symptomatic transmissions,or imperfect data observation,are not ***:To include real-world factors,we expanded the susceptible-exposed-infectiousrecovered(SEIR)model by incorporating pre-symptomatic(P)and asymptomatic(A)states,creating the SEPIAR *** utilizing both stochastic and deterministic versions of the model,and incorporating predetermined time series of Rt,we generated simulated datasets that simulate real-world challenges in estimating *** then compared the performance of our proposed particle filtering method for estimating Rt with the existing EpiEstim approach based on renewal ***:The particle filtering method accurately estimated Rt even in the presence of data with delays,pre-symptomatic transmission,and imperfect *** evaluating via the root mean square error(RMSE)metric,the performance of the particle filtering method was better in general and was comparable to the EpiEstim approach if perfectly deconvolved infection time series were provided,and substantially better when Rt exhibited short-term fluctuations and the data was right ***:The SEPIAR model,in conjunction with the particle filtering method,offers a reliable tool for predicting the transmission trend of COVID-19 and assessing the impact of intervention *** approach enables enhanced monitoring of COVID-19 transmission and can inform public health policies aimed at controlling the spread of the disease.

关键词： Particle filter Sequential Monte Carlo Effective reproduction number COVID-19 Transmission model Compartment model

Sulfur-doped hard carbon hybrid anodes with dual lithium-ion/metal storage bifunctionality for high-energy-density lithium-ion batteries

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Carbon Energy 2023年第1期5卷 71-81页

作者： Sungmin Cho Jong Chan Hyun son Ha Yeonhua Choi Honggyu Seong Jaewon Choi Hyoung-joon Jin Young Soo Yun Program in Environmental and Polymer Engineering Inha UniversityIncheonSouth Korea KU-KIST Graduate School of Converging Science and Technology Korea UniversitySeoulSouth Korea Departmant of Chemistry and Research Institute of Natural Science Gyeongsang National UniversityJinjuSouth Korea Department of Polymer Science and Engineering Inha UniversityIncheonSouth Korea Division of Energy Engineering Kangwon National UniversityGangwon-doSouth Korea

Bifunctional hybrid anodes(BHAs),which are both a high-performance active host material for lithium-ion storage as well as a guiding agent for homogeneous lithium metal nucleation and growth,exhibit significant potential as anodes for next-generation high-energy-density lithium-ion batteries(LIBs).In this study,sulfur-doped hard carbon nanosphere assemblies(S-HCNAs)were prepared through a hydrothermal treatment of a liquid organic precursor,followed by high-temperature thermal annealing with elemental sulfur for application as BHAs for *** a carbonate-based electrolyte containing fluoroethylene carbonate additive,the S-HCNAs showed high lithium-ion storage capacities in sloping as well as plateau voltage sections,good rate capabilities,and stable *** addition,high average Coulombic efficiencies(CEs)of~96.9%were achieved for dual lithium-ion and lithium metal storage *** the LIB full-cell tests with typical NCM811 cathodes,the S-HCNA-based BHAs containing~400 mA h g^(−1) of excess lithium led to high energy and power densities of~500Wh kg^(−1) and~1695Wkg^(−1),respectively,and a stable cycling performance with~100%CEs was achieved.

关键词： hard carbon hybrid anode lithium-ion batteries lithium metal anode lithium metal batteries sulfur-doped carbon