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1:12富铁稀土合金化合物的相变和磁性能研究（英文）

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1:12富铁稀土合金化合物的相变和磁性能研究（英文）

Enhanced charge separation by interchain hole delocalization in nonfullerene acceptor-based bulk heterojunction materials

中国稀土学会第四届青年学术会议

作者：千辉东韩景致徐庆杨金波 park jihoon Choi Chul-jin 北京大学物理学院人工微结构和介观物理国家重点实验室北京大学凝聚态物理与材料物理研究所北京市磁电功能材料与器件重点实验室北京大学长三角光电科学研究院韩国材料研究院(KIMS)

Rare-earth intermetallic compounds of R(Fe,M)(R = rare earth elements, M = transition metals) with ThMn structure have been known to be promising permanent magnetic materials since the 1980s [1]. Recently, increasing demand for R has pushed the industry to seek ways to reduce the R-content in hard magnetic materials. In case, strong magnets with the ThMn type of structure received much attention [2]. However, during the several tens of years, the research about ThMn magnetic materials was not made a breakthrough, due to the rapid development of NdFeB. As a turning point of the ThMn-type Fe-rich compounds research, ThMn-type Sm(FeCo) compound films with a saturation magnetization of 1.78 T, an anisotropy field of 12 T, and a Curie temperature of 586 °C, all of which are superior to those for NdFeB [3], were successfully produced. However, it still has difficulty in stabilizing the unstable ThMn phase in fabricating magnetic powders and bulks. In previous research, the ThMn structure is also metastable and partial Fe atoms must be substituted with phase stabilizing element(s), such as Ti, V, Cr, Mn, Mo, W, Al, and Si, which results in magnetization reduction. So, decreasing magnetization or coercivity with the non-magnetic elements substitution is a new challenge for the ThMn-type Sm(FeCo) compound research. Therefore, we have developed a new fabrication method to produce a high-density Sm(FeCo)Ti bulk with high purity and magnetic properties and investigated Si substitution or doping effects. The purity of the hard magnetic ThMn phase in the bulk magnet reached higher than 97 wt.%. The remanent magnetization and maximum energy product of the prepared Sm(FeCo)Ti bulk reached high values of 96.0 emu/g and 12.22 MGOe, respectively, as shown in Fig. 1(a). To investigate the effect of substituted elements in the ThMn-type Fe-rich compounds Sm(FeCo)Si and Sm(FeCo)Ti+Si(x = 0, 0.5, and 1) ribbons were produced using a melt spinning method. The magnetic properties of the Sm(

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Carbon Energy 2023年第7期5卷 27-37页

作者： Chang-Mok Oh Sujung park jihoon Lee Sung Heum park Shinuk Cho In-Wook Hwang Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangjuRepublic of Korea Department of Physics and Energy Harvest Storage Research Center University of UlsanUlsanRepublic of Korea Department of Physics Pukyong National UniversityBusanRepublic of Korea

Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized ***,the driving force that leads to this reduction was not clearly *** this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ *** demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination *** driving force for this deactivation was determined to be the improved interchain hole delocalization between the *** enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)*** particular,increased splitting between the polaron PIA bands was ***,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.

关键词： bulk heterojunction interchain hole delocalization nonfullerene acceptor photoinduced absorption spectroscopy solar cell

Multi-objective optimization of the cathode catalyst layer micro-composition of polymer electrolyte membrane fuel cells using a multi-scale,two-phase fuel cell model and data-driven surrogates

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Journal of Energy Chemistry 2023年第6期81卷 28-41,I0003页

作者： Neil Vaz Jaeyoo Choi Yohan Cha jihoon Kong Yooseong park Hyunchul Ju Department of Mechanical Engineering Inha University100 Inha-ro Michuhol-GuIncheon 22212Republic of Korea

Polymer electrolyte membrane fuel cells(PEMFCs)are considered a promising alternative to internal combustion engines in the automotive *** commercialization is mainly hindered due to the cost and effectiveness of using platinum(Pt)in *** cathode catalyst layer(CL)is considered a core component in PEMFCs,and its composition often considerably affects the cell performance(V_(cell))also PEMFC fabrication and production(C_(stack))*** this study,a data-driven multi-objective optimization analysis is conducted to effectively evaluate the effects of various cathode CL compositions on Vcelland *** essential cathode CL parameters,i.e.,platinum loading(L_(Pt)),weight ratio of ionomer to carbon(wt_(I/C)),weight ratio of Pt to carbon(wt_(Pt/c)),and porosity of cathode CL(ε_(cCL)),are considered as the design *** simulation results of a three-dimensional,multi-scale,two-phase comprehensive PEMFC model are used to train and test two famous surrogates:multi-layer perceptron(MLP)and response surface analysis(RSA).Their accuracies are verified using root mean square error and adjusted R^(2).MLP which outperforms RSA in terms of prediction capability is then linked to a multi-objective non-dominated sorting genetic algorithmⅡ.Compared to a typical PEMFC stack,the results of the optimal study show that the single-cell voltage,Vcellis improved by 28 m V for the same stack price and the stack cost evaluated through the U.S department of energy cost model is reduced by$5.86/k W for the same stack performance.

关键词： Polymer electrolyte membrane fuel cell Surrogate modeling Multi-layer perceptron(MLP) Response surface analysis(RSA) Non-dominated sorting genetic algorithmⅡ(NSGAⅡ)

Versatile control of concentration gradients in non-fullerene acceptor-based bulk heterojunction films using solvent rinse treatments

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Green Energy & Environment 2022年第5期7卷 1102-1110页

作者： Chang-Mok Oh Soyeong Jang jihoon Lee Sung Heum park In-Wook Hwang Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangju61005Republic of Korea Department of Physics Pukyong National UniversityBusan48513Republic of Korea

Solvent rinse treatments using polar methanol(Me OH)and nonpolar n-hexane have been developed for controlling material concentration gradients along the longitudinal direction of non-fullerene acceptor-based bulk heterojunction(BHJ)films comprised of electron donor polymer,PBDB-T and acceptor,*** the used solvents(chlorobenzene with 1 vol%DIO)were completely evaporated,ITIC-m rich domains were formed at the top surface of the BHJ films after they were rinsed with Me OH,as evidenced by water contact angle,atomic force microscopy,time-of-flight secondary ion mass spectroscopy,which led to enhanced electron transport in the conventional structure of organic solar cells(OSCs).In contrast,after rinsing with n-hexane,ITIC-m rich domains were formed at the bottom surface of the films,which improved electron transport in the inverted structure *** enhanced carrier transports increased the PCEs(11.80%and 11.15%)in both conventional and inverted OSCs by 10.29%and 10.35%compared with control *** versatile control of material concentration gradients is determined to be feasible owing to the chemical interaction of the used substrates(glass,PEDOT:PSS,and Zn O)and rinsing solvents.

关键词： films treatment heterojunction

Dynamic Behavior and Deformation Analysis of the Fish Cage System Using Mass-Spring Model

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China Ocean Engineering 2015年第3期29卷 311-324页

作者： Chun Woo LEE jihoon LEE Subong park Division of Marine Production System Management Pukyong National University Division of Marine Technology Chonnam National University Department of Fisheries Physics Pukyong National University

Fish cage systems are influenced by various oceanic conditions, and the movements and deformation of the system by the external forces can affect the safety of the system itself, as well as the species of fish being cultivated. Structural durability of the system against environmental factors has been major concern for the marine aquaculture system. In this research, a mathematical model and a simulation method were presented for analyzing the performance of the large-scale fish cage system influenced by current and waves. The cage system consisted of netting, mooring ropes, floats, sinkers and floating collar. All the elements were modeled by use of the mass-spring model. The structures were divided into finite elements and mass points were placed at the mid-point of each element, and mass points were connected by springs without mass. Each mass point was applied to external and internal forces, and total force was calculated in every integration step. The computation method was applied to the dynamic simulation of the actual fish cage systems rigged with synthetic fiber and copper wire simultaneously influenced by current and waves. Here, we also tried to find a relevant ratio between buoyancy and sinking force of the fish cages. The simulation results provide improved understanding of the behavior of the structure and valuable information concerning optimum ratio of the buoyancy to sinking force according to current speeds.

关键词： fish cage mathematical model aquaculture computer simulation mass-spring model

Optimization of the pulse width and injection time in a double-pass laser amplifier

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High Power Laser Science and Engineering 2018年第4期6卷 91-97页

作者： Daewoong park jihoon Jeong Tae Jun Yu Department of Advanced Green Energy and Environment Handong Global University Global Institute of Laser Technology Global Green Research and Development CenterHandong Global University

We have optimized the input pulse width and injection time to achieve the highest possible output pulse energy in a double-pass laser amplifier using two Nd:YAG rods. For this purpose, we have extended the Frantz–Nodvik equation by simultaneously including both spontaneous emission and pump energy variation. The effective pump energy of the flash lamp was 8.84 J for each gain medium. The energy of 1 J could be amplified to an output energy of 12.17 J with the maximum achieved extraction efficiency of 63.18% when an input pulse having a pulse width of 168 μs is sent 10 μs after the absorbed pump energy becomes the maximum value.

关键词： Frantz–Nodvik equation input pulse optimization pulse overlap pump energy variation spontaneous emission

Experimental Investigation and Numerical Analysis to Develop Low-Energy Large-Midwater Trawls

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China Ocean Engineering 2017年第6期31卷 700-708页

作者： jihoon LEE Taeho KIM Chun-Woo LEE Subong park Division of Marine Technology Chonnam National University Yeosu 550-749 Korea Division of Marine Production System Management Pukyong National University Busan 608-737 Korea Department of Fisheries Physics Pukyong National University Busan 608-737 Korea

Fuel consumption in fisheries is a primary concern because of its effects on the environment and the costs incurred by fishermen. Many studies have been conducted to reduce the fuel consumption in fishing operations. Fuel consumption due to fishing gear during a fishing operation is generally related to the hydrodynamic resistance on the gear. This means that fuel consumption is proportional to the drag created by the towing speed. Based on numerical methods, this study suggests a new approach to reduce fuel consumption in fisheries. The results of the simulation are in good agreement with those of model experiments. The total as well as partial resistance forces on the gear are calculated by simulation. The simulation results suggest improved materials and gear structure for reducing the hydrodynamic forces on the gear while maintaining gear performance. The method for assessing the gear performance involves measuring the height and width of the net mouth. Furthermore, this study investigates the efficiency of a low-energy trawl from an economic point of view. The findings of this study will be useful in reducing greenhouse gas （GHG） emissions in fishing operations, and thereby contribute toward lowering fishing costs by saving fuel.

关键词： low-energy fishing gear numerical methods greenhouse gasesemission hydrodynamic resistance fuelconsumption

Mimicking a Superhydrophobic Insect Wing by Argon and Oxygen Ion Beam Treatment on Polytetrafluoroethylene Film

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Journal of Bionic Engineering 2009年第4期6卷 365-370页

作者： Youngjong Lee Yonghoon Yoo jihoon Kim Sriyulianti Widhiarini Baeho park Hoon Cheol park Kwang Joon Yoon Doyoung Byun Department of Aerospace Information Engineering Konkuk UniversitySeoul 143-701Republic of Korea Department of Physics Konkuk UniversitySeoul 143-701Republic of Korea Department of Advanced Technology Fusion Konkuk UniversitySeoul 143-701Republic of Korea

Biological tiny structures have been observed on many kinds of surfaces such as lotus leaves and insect wings,which enhance the hydrophobicity of the natural surfaces and play a role of *** presented the fabrication technology of a superhydrophobic surface using high energy ion *** insect wings that mimic the morphology and the superhydrophobocity of cicada's wings were successfully fabricated using argon and oxygen ion beam treatment on a polytetrafluoroethylene (PTFE)*** wing structures were supported by carbon/epoxy fibers as artificial flexible veins that were bonded through an autoclave *** morphology of the fabricated surface bears a strong resemblance to the wing surface of a cicada,with contact angles greater than 160°,which could be sustained for more than two months.

关键词： superhydrophobic insect wing mimicry of the wing ion beam treatment artificial flapper dynamic contact angle

Molecular approaches for the detection and monitoring of microbial communities in bioaerosols:A review

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Journal of Environmental Sciences 2017年第1期29卷 234-247页

作者： Keunje Yoo Tae Kwon Lee Eun Joo Choi jihoon Yang Sudheer Kumar Shukla Sang-il Hwang Joonhong park Department of Civil and Environmental Engineering Yonsei UniversitySeoul 03722South Korea Department of Environmental Engineering Yonsei UniversityWonju 26493South Korea Department of Systems Biology Yonsei UniversitySeoul 03722South Korea Department of Built and Natural Environment Caledonian College of EngineeringSultanate of Oman Division of Natural Resources Conservation Korea Environment InstituteSejong-si 30147South Korea

Bioaerosols significantly affect atmospheric processes while they undergo long-range vertical and horizontal transport and influence atmospheric chemistry and physics and climate *** evidence suggests that exposure to bioaerosols may cause adverse health effects,including severe *** of bioaerosols have primarily focused on their chemical composition and largely neglected their biological composition and the negative effects of biological composition on ecosystems and human ***,current molecular methods for the identification,quantification,and distribution of bioaerosol agents are *** developments in environmental microbiology technology would be favorable in elucidation of microbial temporal and spatial distribution in the atmosphere at high *** addition,these provide additional supports for growing evidence that microbial diversity or composition in the bioaerosol is an indispensable environmental aspect linking with public health.

关键词： Bioaerosol Airborne microbial community Molecular methods Metagenomics