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Augmenting freshwater availability in mountain headwater streams:Assessing the sustainability under baseline and future climate change scenarios

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International Soil and Water Conservation Research 2022年第2期10卷 293-307页

作者： Bisrat Ayalew Yifru Il-Moon Chung Min-Gyu Kim Sun Woo Chang Department of Land Water and Environment ResearchKorea Institute of Civil Engineering and Building TechnologyGoyang10223South Korea Department of Civil and Environmental Engineering University of Science and TechnologyDaejeon34113South Korea

Mountain headwater streams are important freshwater sources,but they are mostly intermittent and highly susceptible to climate change.This paper examines the sustainability of augmented freshwater availability in mountain headwater streams for water supply under baseline and future climate change scenarios using an integrated modeling approach.The climate change data in the 2040s(2030e2059),under Representative Concentration Pathway 4.5 and 8.5 scenarios,were downscaled for the impact assessment.In the region,climate change raises the average precipitation by 5e7%and the temperature by 13e15%in the 2040s.SWATeMODFLOW model,integrating Soil and Water Assessment Tool(SWAT2012)and finite-difference Modular Groundwater Flow(MODFLOW)models in a single package,was used to assess the water balance.Results show that extracting a minimum of 16.2 m^(3)/day from the sand storage and 30 m^(3)/day from the aquifer was possible without affecting the groundwater table and water yield.The average annual catchment recharge was 6%of the precipitation under the baseline simulation.Climate change is projected to reduce the average water yield and groundwater recharge by 26%and 19%,respectively.However,the water supply-demand is significantly small compared to the exploitable rate of water in the area.This study was based on limited data,and therefore the findings need to be interpreted with caution,though the model output was validated using satellite products.Construction of a series of sand dams is suggested to maximize the benefit under the potential climate change and water supply-demand increase.

关键词： Headwater stream Sand dam Korea SWATeMODFLOW Water conservation Climate change

晶格应变和异质界面工程协同促进铋基催化剂高效电催化CO_(2)还原生成甲酸

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Science China Materials 2023年第4期66卷 1398-1406页

作者：魏晓倩李子健 Haeseong Jang min gyu kim 秦清刘希恩 College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China Department of Chemistry City University of Hong KongHong KongChina Beamline Research Division Pohang Accelerator Laboratory(PAL)Pohang 37673Republic of Korea Energy Storage and Distributed Resources Division Lawrence Berkeley National LaboratoryBerkeley CA 94720USA

表面应力耦合异质结构是一种改善非均相催化剂催化性能的有效策略.它可以在调控催化剂电子结构的同时,促进电荷传输.一般来说,Bi基催化剂对CO_(2)电还原为甲酸的选择性高于ZnO,但是金属Bi的价格高于Zn.本文以十六烷基三甲基溴化铵为模板... 详细信息

表面应力耦合异质结构是一种改善非均相催化剂催化性能的有效策略.它可以在调控催化剂电子结构的同时,促进电荷传输.一般来说,Bi基催化剂对CO_(2)电还原为甲酸的选择性高于ZnO,但是金属Bi的价格高于Zn.本文以十六烷基三甲基溴化铵为模板剂,通过一步水热法合成了一种具有多孔纳米片形貌的Bi_(2)O_(2)CO_(3)/ZnO异质结催化剂,用于高效电催化CO_(2)还原制备甲酸.在-1.0 V vs.RHE下,该催化剂展现出最大甲酸盐法拉第效率(92%),且在施加-1.2 V vs.RHE电压下甲酸盐偏电流密度为200 m A mg_(Bi)^(-1).更重要的是,对Bi的质量进行归一化发现,Bi_(2)O_(2)CO_(3)/ZnO的质量活度比纯Bi_(2)O_(2)CO_(3)的质量活度提升了3.1倍.通过X-射线光电子能谱和X-射线吸收谱测试表明,在该催化剂中,界面Zn原子电荷向Bi原子转移,形成了富电子的Bi_(2)O_(2)CO_(3)表面,有利于CO_(2)的捕获和活化;而异质结构引起的压缩应力有利于优化反应中间体的吸附能,二者协同提高了Bi_(2)O_(2)CO_(3)/ZnO电催化CO_(2)还原生成甲酸的选择性和活性.

关键词：十六烷基三甲基溴化铵电催化非均相催化剂异质界面电还原吸收谱吸附能异质结构

Oxygen-deficient SnO_(2)nanoparticles with ultrathin carbon shell for efficient electrocatalytic N_(2)reduction

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Green Energy & Environment 2022年第4期7卷 672-679页

作者： Guangkai Li Haeseong Jang Zijian Li Jia Wang Xuqiang Ji min gyu kim Xien Liu Jaephil Cho State Key Laboratory Base of Eco-chemical Engineering College of Chemical EngineeringCollege of Chemistry and Molecular EngineeringQingdaoUniversity of Science and TechnologyQingdao266042China Department of Energy Engineering School of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)Ulsan689-798South Korea College of Materials Science and Engineering Qingdao UniversityQingdao266071China Beamline Research Division Pohang Accelerator Laboratory(PAL)Pohang790-784South Korea

For high-efficiency NH_(3)synthesis via ambient-condition electrohydrogenation of inert N_(2),it is pivotal to ingeniously design an active electrocatalyst with multiple features of abundant surfacial deficiency,good conductivity and large surface area.Here,oxygen-deficient SnO_(2)nanoparticles encapsulated by ultrathin carbon layer(d-SnO_(2)@C)are developed by hydrothermal deposition coupled with annealing process,as promising catalysts for ambient electrocatalytic N_(2)reduction.d-SnO_(2)@C exhibits high activity and excellent selectivity for electrocatalytic conversion of N_(2)to NH_(3)in acidic electrolytes,with Faradic efficiency as high as 12.7%at-0.15 V versus the reversible hydrogen electrode(RHE)and large NH_(3)yield rate of 16.68μg h^(-1)mgcat^(-1)at-0.25 V vs.RHE in 0.1 mol L^(-1)HCl.Benefiting from the structural superiority of enhanced charge transfer efficiency and optimized surface states,d-SnO_(2)@C also achieves excellent long-term stability.

关键词： N_(2)reduction reaction NH_(3)synthesis SnO_(2) Electrocatalysts Ambient conditions

单原子Ru修饰的三维多级Co(OH)F纳米片阵列高效催化析氧反应

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Science China Materials 2021年第6期64卷 1408-1417页

作者：周士正 Haeseong Jang 秦清李子健 min gyu kim 李创刘希恩 Jaephil Cho State Key Laboratory Base of Eco-Chemical Engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China Department of Energy Engineering Department of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)Ulsan 44919South Korea Department of Chemistry City University of Hong KongHong KongChina Beamline Research Division Pohang Accelerator Laboratory(PAL)Pohang 37673South Korea

单原子与基底之间的电子耦合在提升单原子催化剂的本征催化活性方面起到至关重要的作用.本文通过一步水热法在温和条件下制备了单原子Ru修饰的三维多级Co(OH)F纳米片阵列催化剂.该催化剂在1 mol L^(−1)KOH电解液中展现出高的电催化析氧... 详细信息

单原子与基底之间的电子耦合在提升单原子催化剂的本征催化活性方面起到至关重要的作用.本文通过一步水热法在温和条件下制备了单原子Ru修饰的三维多级Co(OH)F纳米片阵列催化剂.该催化剂在1 mol L^(−1)KOH电解液中展现出高的电催化析氧反应活性和稳定性,在10和500 mA cm^(−2)的电流密度下分别表现出200和326 mV的过电位.通过对催化剂析氧反应前后的电子结构和表面化学态的研究发现,单原子Ru和Co(OH)F之间强烈的电子耦合诱导体系电荷重新分布,并抑制了Ru在高的OER电势下被过度氧化为过高的价态(大于+4价).本工作提供了一个通过羟基氟化钴稳定单原子Ru,以提高大电流下析氧反应的活性和稳定性的策略.

关键词： electrocatalyst oxygen evolution reaction single atom ruthenium electronic coupling

Electron-deficient ZnO induced by heterointerface engineering as the dominant active component to boost CO_(2)-to-formate conversion

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Carbon Energy 2024年第5期6卷 127-136页

作者： Qing Qin Zijian Li Yingzheng Zhang Haeseong Jang Li Zhai Liqiang Hou Xiaoqian Wei Zhe Wang min gyu kim Shangguo Liu Xien Liu College of Chemical Engineering Qingdao University of Science and TechnologyQingdaoChina Department of Chemistry City University of Hong KongHong Kong SARChina Department of Advanced Materials Engineering Chung-Ang UniversityAnseong-siGyeonggi-doRepublic of Korea Beamline Research Division Pohang Accelerator Laboratory(PAL)PohangRepublic of Korea

Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,but seldom do they exhibit excellent selectivity toward formate.In this article,we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency(FE)of 86%at−0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO_(2) to formate than pristine ZnO and ZnSnO3.In particular,the FEs of the C1 products(CO+HCOO−)exceed 98%over the potential window.The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center,which results in moderate Zn-O hybridization of HCOO*and weakened Zn-C hybridization of competing COOH*,thus greatly boosting the HCOOH generation.Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO_(2) reduction.

关键词： charge redistribution CO_(2)reduction reaction electrocatalyst heterointerfaces selectivity

A huge thrombosed aneurysm of a saphenous vein graft leading to compression of cardiac structures： role of multimodality imaging

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Journal of Geriatric Cardiology 2017年第8期14卷 536-537页

作者： Byung gyu kim In-Cheol kim Seok-min Kang Young-Nam Youn Division of Cardiology Department of Internal Medicine Severance Cardiovascular Hospital Yonsei University College of Medicine Seoul South Korea Division of Cardiology Department of Internal Medicine Seoul Paik Hospital Inje University College of Medicine Seoul South Korea Division of Cardiology Department of Internal Medicine Keimyung University Dongsan Medical Center Daegu South Korea Department of Thoracic and Cardiovascular Surgery Severance Cardiovascular Hospital Yonsei University College of Medicine Seoul South Korea

Aneurysmal change of saphenous vein grafts （SVG） is a rare condition that predominantly develops 10-20 years after coronary artery bypass graft （CABG）. Natural course includes mechanical complications due to mass effect, myocardial infarction and aneurysmal rupture. Aneurysmectomy can be considered when it induces such complications. We demonstrate complete set of diagnosis, treatment and post-operative imaging of a huge SVG aneurysm that was successfully treated with surgical resection.

关键词：静脉移植动脉瘤心脏结构成像多模态血栓性压缩冠状动脉

Cavity-Suppressing Electrode Integrated with Multi-Quantum Well Emitter:A Universal Approach Toward High-Performance Blue TADF Top Emission OLED

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Nano-Micro Letters 2022年第4期14卷 75-89页

作者： Il gyu Jang Vignesh Murugadoss Tae Hoon Park Kyung Rock Son Ho Jin Lee WanQi Ren min Ji Yu Tae Geun kim School of Electrical Engineering Korea UniversityAnam-ro 145Seongbuk-guSeoul 02841Republic of Korea

A novel device structure for thermally activated delayed fluorescence(TADF)top emission organic light-emitting diodes(TEOLEDs)that improves the viewing angle characteristics and reduces the efficiency roll-off is presented.Furthermore,we describe the design and fabrication of a cavity-suppressing electrode(CSE),Ag(12 nm)/WO_(3)(65 nm)/Ag(12 nm)that can be used as a transparent cathode.While the TADF-TEOLED fabricated using the CSE exhibits higher external quantum efficiency(EQE)and improved angular dependency than the device fabricated using the microcavity-based Ag electrode,it suffers from low color purity and severe efficiency roll-off.These drawbacks can be reduced by using an optimized multi-quantum well emissive layer(MQW EML).The CSE-based TADF-TEOLED with an MQW EML fabricated herein exhibits a high EQE(18.05%),high color purity(full width at half maximum~59 nm),reduced efficiency roll-off(~46%at 1000 cd m^(−2)),and low angular dependence.These improvements can be attributed to the synergistic effect of the CSE and MQW EML.An optimized transparent CSE improves charge injection and light outcoupling with low angular dependence,and the MQW EML effectively confines charges and excitons,thereby improving the color purity and EQE significantly.The proposed approach facilitates the optimization of multiple output characteristics of TEOLEDs for future display applications.

关键词： Cavity suppression Multi-quantum well Viewing angle Efficiency roll-off Top emission OLED

Room-temperature lasing from nanophotonic topological cavities

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Light(Science & Applications) 2020年第1期9卷 823-830页

作者： Daria Smirnova Aditya Tripathi Sergey Kruk min-Soo Hwang Ha-Reem kim Hong-gyu Park Yuri Kivshar Nonlinear Physics Center Research School of PhysicsAustralian National UniversityCanberraACT 2601Australia Institute of Applied Physics Russian Academy of ScienceNizhny Novgorod 603950Russia Department of Physics Indian Institute of TechnologyDelhi 110016India Department of Physics Korea UniversitySeoul 02841Republic of Korea

The study of topological phases of light underpins a promising paradigm for engineering disorder-immune compact photonic devices with unusual properties.Combined with an optical gain,topological photonic structures provide a novel platform for micro-and nanoscale lasers,which could benefit from nontrivial band topology and spatially localized gap states.Here,we propose and demonstrate experimentally active nanophotonic topological cavities incorporating Ⅲ-Ⅴ semiconductor quantum wells as a gain medium in the structure.We observe room-temperature lasing with a narrow spectrum,high coherence,and threshold behaviour.The emitted beam hosts a singularity encoded by a triade cavity mode that resides in the bandgap of two interfaced valley-Hall periodic photonic lattices with opposite parity breaking.Our findings make a step towards topologically controlled ultrasmall light sources with nontrivial radiation characteristics.

关键词： lasing singularity narrow

Effects of Craddition on Charpy impact energy in austenitic 0.45C-24Mn-(0,3,6)Cr steels

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Journal of Materials Science & Technology 2020年第15期47卷 21-30页

作者： Seok gyu Lee Bohee kim min Cheol Jo Kyeong-min kim Junghoon Lee Jinho Bae Byeong-Joo Lee Seok Su Sohn Sunghak Lee Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang37673South Korea Steel Products Design Team Hyundai SteelDangjin31779South Korea Steel Products Research Group 1 Technical Research LaboratoriesPOSCOGwangyang57807South Korea Department of Materials Science and Engineering Korea UniversitySeoul02841South Korea

Effects of Cr addition(0,3,and 6 wt%) on Charpy impact properties of Fe-C-Mn-Cr-based steels were studied by conducting dynamic compression tests at room and cryogenic temperatures.At room temperature,deformation mechanisms of Charpy impacted specimens were observed as twinning induced plasticity(TWIP) without any transfo rmation induced plasticity(TRIP) in all the steels.At cryogenic temperature,many twins were populated in the Cr-added steels,but,interestingly,fine ε-martensite was found in the OCr steel,satisfying the Shoji-Nishiyama(S-N) orientation relationship,{111}γ//{0002}ε and γ//ε.Even though the cryogenic-temperature staking fault energies(SFEs) of the three steel were situated in the TWIP regime,the martensitic transformation was induced by Mn-and Cr-segregated bands.In the OCr steel,SFEs of low-(Mn,Cr) bands lay between the TWIP and TRIP regimes which were sensitively affected by a small change of SFE.The dynamic compressive test results well showed the relation between segregation bands and the SFEs.Effects of Cr were known as not only increasing the SFE but also promoting the carbide precipitation.In order to identify the possibility of carbide formation,a precipitation kinetics simulation was conducted,and the predicted fractions of precipitated M23C6 were negligible,0.4-1.1×10-5,even at the low cooling rate of 10℃/s.

关键词： Austenitic high-Mn steels Charpy impact energy Split Hopkinson pressure bar Twinning induced plasticity(TWIP) Transformation induced plasticity(TRIP) Stacking fault energy(SFE)