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Enhancing ammonia production rates from electrochemical nitrogen reduction by engineering three-phase boundary with phosphorus-activated Cu catalysts

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Journal of Energy Chemistry 2023年第9期84卷 394-401页

作者： Jeehye Kim Cho hee lee Yong Hyun Moon min hee lee Eun Hyup Kim Sun hee Choi Youn Jeong Jang Jae Sung lee School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea Department of Chemical Engineering Hanyang UniversitySeoul 04763Republic of Korea Pohang Accelerator Laboratory(PAL) Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea

Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous ***,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) *** eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic *** a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic *** work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.

关键词： Electrochemical nitrogen reduction reaction Ammonia production Phosphorous modified copper electrodes Gas diffusion electrodes Three-phase boundary PTFE coating

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Influence of Tropical Cyclone Landfalls on Spatiotemporal Variations in Typhoon Season Rainfall over South China

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Advances in Atmospheric Sciences 2010年第2期27卷 443-454页

作者： min-hee lee Chang-Hoi HO Joo-Hong KIM Computational Science and Technology Seoul National University School of Earth and Environmental Sciences Seoul National University Met Office Hadley Centre

This study examined the impact of tropical cyclone (TC) landfalls on the spatiotemporal variations in the rainfall over South China for the period 1957–2005. The target region was selected to show the noteworthy contribution of TC landfalls to the total rainfall during the typhoon season (July–October). Two prevailing spatial variations in the rainfall were obtained from an EOF analysis. The first EOF mode displays singlesign variability over South China with an explained variance of 23.4%. The associated time series of this mode fluctuates on a decadal timescale and was found to be correlated with TC genesis in the South China Sea. The second EOF mode shows a seesaw pattern between Hainan Island/Guangdong Province and the remaining regions with an explained variance of 11.4%. This seesaw pattern results from an anti-correlation in seasonal TC landfalls between the two regions, which was found in previous studies. This is related to the strengthening (weakening) of the upper tropospheric jets and the corresponding development of a massive anticyclonic (cyclonic) circulation over East Asia. The EOF analysis was also conducted using just the data for rainfall caused by landfalling TCs. This revealed that the first EOF mode using just the TC-induced rainfall is nearly identical to the second mode from the total rainfall. The obvious seesaw pattern of the first mode when employing just the TC-induced rainfall in the EOF analysis implies that this pattern has larger temporal variability than the single-signed pattern (i.e., the first EOF mode using the total rainfall) in terms of TC landfalls. This study suggests that TC landfalls over South China and the accompanying rainfall significantly modulate the spatial variation of the typhoon season rainfall there.

关键词： rainfall tropical cyclone South China typhoon season

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Technical Note on a Track-pattern-based Model for Predicting Seasonal Tropical Cyclone Activity over the Western North Pacific

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Advances in Atmospheric Sciences 2013年第5期30卷 1260-1274页

作者： Chang-Hoi HO Joo-Hong KIM Hyeong-Seog KIM Woosuk CHOI min-hee lee hee-Dong YOO Tae-Ryong KIM Sangwook PARK School of Earth and Environmental Sciences Seoul National University Korea Polar Research Institute Atmospheric and Oceanic Science Princeton University and NOAA/GFDL Forecast Policy Division Korea Meteorological Administration National Typhoon Center Korea Meteorological Administration

Recently, the National Typhoon Center （NTC） at the Korea Meteorological Administration launched a track-pattern-based model that predicts the horizontal distribution of tropical cyclone （TC） track density from June to October. This model is the first approach to target seasonal TC track clusters covering the entire western North Pacific （WNP） basin, and may represent a milestone for seasonal TC forecasting, using a simple statistical method that can be applied at weather operation centers. In this note, we describe the procedure of the track-pattern-based model with brief technical background to provide practical information on the use and operation of the model. The model comprises three major steps. First, long-term data of WNP TC tracks reveal seven climatological track clusters. Second, the TC counts for each cluster are predicted using a hybrid statistical-dynamical method, using the seasonal prediction of large-scale environments. Third, the final forecast map of track density is constructed by merging the spatial probabilities of the seven clusters and applying necessary bias corrections. Although the model is developed to issue the seasonal forecast in mid-May, it can be applied to alternative dates and target seasons following the procedure described in this note. Work continues on establishing an automatic system for this model at the NTC.

关键词： tropical cyclone western North Pacific seasonal forecast track-pattern-based model hybrid statistical-dynamical approach

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Ascaris-mimicking common bile duct stone: A case report

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World Journal of Clinical Cases 2020年第19期8卷 4499-4504页

作者： Seo-Youn Choi Ha Eun Jo Yun Nah lee Ji Eun lee min hee lee San ghyeok Lim Boem Ha Yi Radiology Soonchunhyang University HospitalBucheonBucheon 14584South Korea Digestive disease center and research institute Soonchunhyang University HospitalBucheonBucheon 14584South Korea

BACKGROUND In most cases,it is not difficult to differentiate common bile duct(CBD)stone from Ascaris infection because they are different disease entities and have different imaging *** two diseases usually demonstrate unique characteristic findings on computed tomography or magnetic resonance ***,we report a rare case from our experience in which a CBD stone mimicked and was misdiagnosed as *** SUMMARY A 72-year-old male presented with elevated serum liver *** tomography showed a hyper-attenuated,elongated lesion in the CBD lumen and associated biliary *** resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography revealed a linear filling defect in the bile ***,elongated echogenic material with a central hypoechogenic area was seen on endoscopic *** the imaging findings caused us to suspect infection with the nematode Ascaris,the lesion was revealed to be a dark-brown-colored CBD stone through endoscopic *** We report a rare case of a CBD stone that mimicked *** also review the literature for side-by-side comparisons of the imaging features of CBD stones and ascariasis.

关键词： Case report Common bile duct Gallstones Ascaris Ascariasis Multidetector computed tomography Magnetic resonance cholangiopancreatography

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无碱CO_(2)加氢高效制甲酸Pd/g-C_(3)N_(4)催化剂的单原子和纳米簇的协同作用

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Chinese Journal of Catalysis 2023年第4期47卷 214-221页

作者： Eun Hyup Kim min hee lee Jeehye Kim Eun Cheol Ra Ju Hyeong lee Jae Sung lee 蔚山国家科学技术研究所能源与化学工程学院(UNIST) 韩国

气候变化威胁人类的生存.化石燃料的过度使用导致CO_(2)持续排放是引起全球变暖和气候变化的主要因素,须尽快减少CO_(2)排放.捕获CO_(2)并将其转化为高附加值的燃料和化学品从而循环利用是减少CO_(2)净排放的有效措施.其中,CO_(2)催化... 详细信息

气候变化威胁人类的生存.化石燃料的过度使用导致CO_(2)持续排放是引起全球变暖和气候变化的主要因素,须尽快减少CO_(2)排放.捕获CO_(2)并将其转化为高附加值的燃料和化学品从而循环利用是减少CO_(2)净排放的有效措施.其中,CO_(2)催化加氢制甲酸(HCOOH)是碳捕获与利用(CCU)的有效途径之一,其产物HCOOH可用于防腐剂、牲畜饲料抗菌剂和食品添加剂,也可作为氢载体和直接甲酸燃料电池的燃料.目前,工业上生产HCOOH的工艺包括两个步骤:甲醇和CO在强碱条件下反应生成甲酸甲酯(HCO_(2)CH_(3)),随后水解为HCOOH.该工艺利用来自化石燃料的两种原料,排放出大量CO_(2),同时在水解步骤中使用了过量的酸性水,因此对生态环境产生一定的危害.近年来,以CO_(2)为可再生原料合成HCOOH被广泛研究,人们探索了电化学、光化学、生物和热化学反应等多种途径将CO_(2)还原为HCOOH,以期实现CO_(2)循环利用.上述方法距实际应用尚有一定距离,其中,CO_(2)催化加氢制HCOOH过程最先进,它与当前许多化学工业过程相似.由于CO_(2)分子的化学稳定性,CO_(2)加氢生成HCOOH在热力学上不利,可通过有机碱和无机碱形成甲酸-碱配合物,推动反应向生成HCOOH方向移动.然而,从甲酸基配合物中提取HCOOH需要额外的分离步骤,因此在无碱条件下直接将CO_(2)加氢生成HCOOH非常重要.本课题组致力于研究无碱条件下g-C_(3)N_(4)负载的Pd(记为Pd/CN)催化剂催化CO_(2)加氢合成HCOOH,前期研究(***.,2016,52,14302-14305和***.,2021,396,395-401)发现,通过控制Pd负载量可改变催化剂中Pd单原子/Pd纳米团簇的比例,且当两种状态Pd达到最佳比例时,催化剂催化活性最高.这表明在无碱CO_(2)加氢过程中,Pd单原子与纳米团簇间存在协同作用.此外,最近有关于单原子和纳米团簇在负载金属催化剂中不同作用的报道,如NixMg1-xO催化逆水气变换反应,Ir1/In_(2)O_(3)和Pd/Fe_(3)O_(4)催化CO_(2)加氢制乙醇反应等,这些工作得出相似的结论:单原子金属对CO_(2)活化有效,而纳米团簇对H_(2)活化有效.这对于设计以CO_(2)和H_(2)为反应物的金属催化剂很重要.本工作旨在考察类似的机理是否适用于Pd/CN催化剂在无碱条件下催化CO_(2)加氢制HCOOH过程.通过控制Pd负载量,合成了含有不同比例Pd单原子和Pd纳米团簇的Pd/CN催化剂,Pd与g-C_(3)N_(4)表面碱性位间的强静电相互作用使合成含有大量Pd单原子的Pd/CN催化剂成为可能.在Pd/CN催化剂催化无碱CO_(2)加氢制HCOOH过程中,当两种状态Pd达到最佳比例时,Pd单原子和Pd纳米簇之间存在协同作用,此时催化剂活性最高.实验表明,Pd纳米簇主要通过解离吸附参与H_(2)活化,Pd单原子对CO_(2)活化更有效.在最佳单原子比(单原子数/(单原子数+纳米簇)为41%)时,该催化剂表现出最高的活性,优于文献报道的相似反应条件下Pd催化剂活性.这些发现将为以CO_(2)和H_(2)分子为反应物的反应的催化剂设计提供一定的参考.

关键词：无碱CO_(2)加氢制甲酸 Pd/g-C_(3)N_(4) 单原子催化剂纳米簇催化剂协同效应

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Optimization of an Artificial Intelligence Database and Camera Installation for Recognition of Risky Passenger Behavior in Railway Vehicles

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Computers, Materials & Continua 2025年第1期82卷 1277-1293页

作者： min-kyeong Kim Yeong Geol lee Won-hee Park Su-hwan Yun Tae-Soon Kwon Duckhee lee Railroad Test&Certification Division Korea Railroad Research Institute(KRRI)Cheoldo BangmulgwanroUiwang-si16105Republic of Korea Railroad Safety Division Korea Railroad Research Institute(KRRI)Cheoldo BangmulgwanroUiwang-si16105Republic of Korea

Urban railways are vital means of public transportation in *** than 30%of metropolitan residents use the railways,and this proportion is expected to *** enhance safety,the government has mandated the installation of closed-circuit televisions in all carriages by ***,cameras still monitored *** address this limitation,we developed a dataset of risk factors and a smart detection system that enables an immediate response to any abnormal behavior and intensive monitoring *** created an innovative learning dataset that takes into account seven unique risk factors specific to Korean railway *** data collection was conducted across the Shinbundang Line of the Incheon Transportation Corporation,and the Ui-Shinseol *** observed several behavioral characteristics and assigned unique annotations to *** also considered carriage *** performance was evaluated by camera placement and *** the camera installation plan was *** dataset will find immediate applications in domestic railway *** artificial intelligence algorithms will be verified shortly.

关键词： AI railway vehicle risk factor smart detection AI training data

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Aligned Ion Conduction Pathway of Polyrotaxane‑Based Electrolyte with Dispersed Hydrophobic Chains for Solid‑State Lithium–Oxygen Batteries

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Nano-Micro Letters 2025年第2期17卷 169-186页

作者： Bitgaram Kim Myeong‑Chang Sung Gwang‑hee lee Byoungjoon Hwang Sojung Seo Ji‑Hun Seo Dong‑Wan Kim Department of Materials Science and Engineering Korea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea School of Civil Environmental and Architectural EngineeringKorea University145 Anam‑RoSeongbuk‑GuSeoul 02841Republic of Korea Materials Science and Chemical Engineering Center Institute for Advanced Engineering(IAE)Yongin 17180Republic of Korea

A critical challenge hindering the practical application of lithium–oxygen batteries(LOBs)is the inevitable problems associated with liquid electrolytes,such as evaporation and safety *** study addresses these problems by proposing a modified polyrotaxane(mPR)-based solid polymer electrolyte(SPE)design that simultaneously mitigates solvent-related problems and improves ***-SPE exhibits high ion conductivity(2.8×10^(−3)S cm^(−1)at 25℃)through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain *** this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 *** situ Raman spectroscopy reveals the presence of an LiO_(2)intermediate alongside Li_(2)O_(2)during oxygen *** situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture,as demonstrated by the air permeability *** present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

关键词： Solid polymer electrolyte Lithium-oxygen batteries Polyrotaxane ion conductivity Hydrophobic chain

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A density functional theory study of the tunable structure, magnetism and metal-insulator phase transition in VS2 monolayers induced by in-plane biaxial strain

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Nano Research 2015年第4期8卷 1348-1356页

作者： min Kan Bo Wang Young hee lee Qiang Sun Department of Materials Science and Engineering Peking University 8eijing 100871 China Center for Integrated Nanostructure Physics Institute for Basic Science Sungkyunkwan University Suwon 440-746 Korea Department of Physics and Department of Energy Science Sungkyunkwan University Suwon 440-746 Korea School of Mathematical Sciences Peking University Beijing 100871 China Center forAppfied Physics and Technology Peking University Beijing 100871 China

We report a density functional theory study of a phase transition of a VS2 monolayer that can be tuned by the in-plane biaxial strain. This results in both a metal-insulator transition and a low spin-high spin magnetic transition. At low temperature, the semiconducting H-phase is stable and large strain （〉3%） is required to provoke the transition. On the other hand, at room temperature （300 K）, only a small tensile strain of 2% is needed to induce the phase transition from the semiconducting H-phase to the metallic T-phase together with the magnetic transition from high spin to low spin. The phase diagram dependence on both strain and temperature is also discussed in order to provide a better understanding of the phase stability of VS2 monolayers.

关键词： phase transition biaxial strain phase diagram density functional theory(DFT) transition metaldichalcogenide(TMD) materials

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Comparative analysis on homogeneity of Pb and Cd in epoxy molding compounds

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 160-164页

作者： Kyun-Gmee lee Yong-Keun SON Jin-Sook lee Tai-min NOH hee-Soo lee Department of Chemistry Sungkyunkwan University Department of Chemistry Yonsei University School of Materials Science and Engineering Pusan National University

Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components, were designed and investigated in terms of stability and homogeneity. Reference materials with two concentration levels of heavy metals were prepared by spiking Pb and Cd compounds to epoxy molding compounds made by mixing silica powders and epoxy resin. The concentration changes of the reference materials during stability test for 1 a were not observed. In the homogeneity assessment, the as-prepared reference materials were studied by using three different analytical tools, inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluoroescence spectrometry (XRF) and laser ablation ICP mass. The results show different homogeneities by the characteristics of analytical tools and the materials.

关键词： epoxy molding compound Pb Cd reference materials homogeneity

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A unique and well-designed 2D graphitic carbon nitride with sponge-like architecture for enhanced visible-light photocatalytic activity

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Journal of Materials Science & Technology 2023年第28期159卷 99-111页

作者： Mahdieh Razi Asrami Milad Jourshabani min hee Park Daiha Shin Byeong-Kyu lee Department of Civil and Environment Engineering University of UlsanDaehakro 93NamguUlsan 680-749Republic of Korea Western Seoul Center Korea Basic Science InstituteSeoul 03759Republic of Korea

A unique and well-designed 2D graphitic carbon nitride(g-CN)with sponge-like architecture has been successfully synthesized by engineering supramolecular self-assembly and well-organized SiO 2 *** resulting material showed great optical and textural characteristics with plenty of open and uni-form pores,which are very helpful whether for multiple light scattering or mass *** formation of boosted delocalizedπ-conjugated electrons at the molecular level and condensed heptazine building blocks result in enhanced carrier density and charge transfer *** emission spectroscopy and time-resolved fluorescence lifetime(TRPL)strongly confirmed the enhancement of light harvesting and prolonged charge carrier *** optimized sample exhibited a degradation performance of 95%of bisphenol A(BPA,10 mg L-1)after 60 min under visible-light irradiation at pH=*** the scavenging experiments,probing experiments as well as electron paramagnetic resonance(EPR)confirm that•O 2-is the dominant reactive species that fragments bisphenol ***,density functional theory(DFT)calculations unveil that the BPA interaction with a modified g-CN containing porous structure is energeti-cally more favorable than non-porous pure ***,the toxicity assessment showed that the final degradation products were placed in the non-harmful category based on acute and chronic *** study presents a promising strategy to modify the g-CN properties and provides an efficient technique for boosting its visible-light photocatalytic activity.

关键词： Sponge-like Carbon nitride Photocatalysis Visible-light

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