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Fault area estimation using traveling wave for wide area protection

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Journal of Modern Power Systems and Clean Energy 2016年第3期4卷 478-486页

作者： Jae-won LEE won-ki kim Joon HAN won-Hyeok JANG Chul-Hwan kim Department of Electrical and Computer Engineering Sungkyunkwan UniversitySuwonRepublic of Korea Daewoo Shipbuilding&Marine Engineering Co. Ltd.GeojeRepublic of Korea Electrical and Computer Engineering Department University of Illinois at Urbana-ChampaignChampaignILUSA

As the increasing number of Phasor Measurement Units(PMUs) are deployed, wide area protection in power systems has been gaining interest. In particular, fault detection, fault classification and fault area estimation are essential to reduce the damage of faults, and even prevent catastrophic cascades of failures. In this paper, we present a scheme for fault area estimation using PMUs and traveling wave theory. The purpose of this paper is to formulate a scheme for fault area estimation by calculating the approximate fault location based on traveling wave *** research has targeted at reliable operation of wide transmission system through the estimation of fault *** verify the suggested scheme, the various simulations are performed in practical Korean power transmission *** simulation results show that the proposed scheme has a good performance with high accuracy for estimating fault area.

关键词： Fault area estimation Phasor measurement unit(PMU) Transmission line system Traveling wave Wide area protection

Gas Sensing Characteristics of SnO_2 Whiskers Prepared from SNC_2O_4

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稀有金属材料与工程 2006年第A3期35卷 100-103页

作者： ki-won kim Pyeong-Seok Cho Jong-Heun Lee Seong-Hyeon Hong Department of Materials Science & Engineering Korea UniversitySeoui 136-713Korea School of Materials Science and Engineering and Nano Systems Institute-National Core Research Center Seoul National UniversitySeoul 151-744Korea

SnO_2 whiskers were prepared from the decomposition of whisker-like SnC_2O_4,which was precipitated by a reaction between an aqueous SnCl_2 and oxalic acid solution at high solution temperatures (80℃).After the decomposition of SnC_2O_4 at 450℃,SnO_2 whiskers containing both of rutile and metastable orthorhombic phases were obtained with the content of the orthorhombic phase decreasing with increasing heat-treatment temperature and *** effect of orthorhombic phase upon CO gas sensitivity was investigated by measuring the evolution of the primary particle size and the CO sensitivity with repeating heat treatment at 450℃.The 50μg/g CO sensitivity increased with decreasing concentration of the orthorhombic phase despite particle coarsening,which suggests that the orthorhombic phase is detrimental to the CO gas sensitivity.

关键词： SnO2 whisker orthorhombic phase gas sensor SnC2O4

Segmental artery injury during transforaminal percutaneous endoscopic lumbar discectomy:Two case reports

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World Journal of Clinical Cases 2022年第33期10卷 12345-12351页

作者： Wan-Jae Cho ki-won kim Hyung-Youl Park Bo-Hyoung kim Jun-Seok Lee Department of Orthopedic Surgery Yeouido St.Mary’s HospitalCollege of MedicineCatholic University of KoreaSeoul 07345South Korea Department of Orthopedic Surgery Eunpyeong St.Mary’s HospitalCollege of MedicineCatholic University of KoreaSeoul 03312South Korea

BACKGROUND Since Kambin experimentally induced arthroscopy to treat herniated nucleus pulposus,percutaneous endoscopic lumbar discectomy(PELD)has been *** branch of the segmental artery around the neural foramen may be damaged during PELD using the transforaminal *** report 2 rare cases in which segmental artery injury that occurred during PELD was treated with emergency *** SUMMARY In case 1,a 31-year-old man was transferred to our emergency department with left lower quadrant abdominal pain after PELD at a local *** spine magnetic resonance imaging after the surgery showed a hematoma of the left retroperitoneal area and the psoas muscle *** suspicion of vascular injury,arteriography was *** and blood leakage from the left 4th lumbar segmental artery into the abdominal cavity were *** transarterial embolization was performed using fibered microcoils for bleeding of the segmental *** case 2,a 75-year-old woman was transferred to our emergency department with low blood pressure,right flank pain,and drowsy mental status after PELD at a local *** the patient arrived at the emergency room,the blood pressure decreased from 107/55 mmHg to 72/47 *** blood pressure *** suspicion of vessel injury,arteriography was performed,and the right 4th lumbar segmental artery rupture was *** transarterial embolization was performed for bleeding of segmental *** We were able to find the bleeding focus by angiography and treat the injury of the segmental artery successfully through emergency transarterial embolization.

关键词： Percutaneous endoscopic lumbar discectomy Segmental artery injury Transarterial embolization Angiography Case report

Driving inward growth of lithium metal in hollow microcapsule hosts by heteroatom‐controlled nucleation

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Carbon Energy 2024年第8期6卷 262-272页

作者： Siwon kim Hong Rim Shin ki Jae kim Min‐Sik Park Jong‐won Lee Division of Materials Science and Engineering Hanyang UniversitySeoulRepublic of Korea Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)DaeguRepublic of Korea Department of Energy Science Sungkyunkwan UniversitySuwonRepublic of Korea Department of Advanced Materials Engineering for Information and Electronics Integrated Education for Frontier Science and Technology(BK21 Four)Kyung Hee UniversityYonginRepublic of Korea

The application of Li metal anodes in rechargeable batteries is impeded by safety issues arising from the severe volume changes and formation of dendritic Li ***‐dimensional hollow carbon is receiving increasing attention as a host material capable of accommodating Li metal inside its cavity;however,uncontrollable and nonuniform deposition of Li remains a *** this study,we synthesize metal–organic framework‐derived carbon microcapsules with heteroatom clusters(Zn and Ag)on the capsule walls and it is demonstrated that Ag‐assisted nucleation of Li metal alters the outward‐to‐inward growth in the microcapsule ***‐incorporated microcapsules are prepared via chemical etching of zeolitic imidazole framework‐8 polyhedra and are subsequently decorated with Ag by a galvanic displacement reaction between Ag^(+)and metallic *** introduced Ag significantly reduces the energy barrier and increases the reaction rate for Li nucleation in the microcapsule host upon Li *** combined electrochemical,microstructural,and computational studies,we verify the beneficial role of Ag‐assisted Li nucleation in facilitating inward growth inside the cavity of the microcapsule host and,in turn,enhancing electrochemical *** study provides new insights into the design of reversible host materials for practical Li metal batteries.

关键词： hollow carbon hosts lithium metal batteries lithium plating metal-organic frameworks nucleation

Performance and genetic diversity of 23 provenances of northern red oak(Quercus rubra L.)after 25 years of growth in South Korea

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Journal of Forestry Research 2021年第5期32卷 2181-2188页

作者： ki-won kim Kyoung-Mi Lee Soon-Ho Kwon Ji-Min Park Yang-Gil kim Hye-In Kang Da-Bin Yum Kyu-Suk Kang Department of Agriculture Forestry and BioresourcesSeoul National UniversitySeoul 08826Republic of Korea Department of Forest Bioresources National Institute of Forest ScienceSuwon 16631Republic of Korea Department of Plant Resource Research Korea National ArboretumPocheon 11186Republic of Korea Research Institute of Agriculture and Life Sciences CALS_SNUSeoul 08826Republic of Korea

Growth traits and genetic diversity of 23 provenances of Quercus rubra introduced from North America were analyzed in a provenance trial established with a randomized block design in Hwaseong,Gyeonggi,South Korea in *** variables and survival at age 25 were compared with results from early ***,DBH,volume and stem straightness of *** was better than those of the domestic oak(Quercus accutissima).Growth of the Dunham Island provenance from New York was the best among the 23 provenances that of the Eagle River provenance from Wisconsin was *** rate at age25 was on average 52%.The longitude of seed origin and growth of provenance were consistently significantly negatively correlated at all *** of coastal provenances was superior to that of the inland provenances,which were separated by the Appalachian *** diversity and genetic distance among the provenances were evaluated using micro satellite *** allelic frequencies showed high polymorphism in 10 microsatellite loci,and 292 alleles were *** 10 loci,two were commonly found in the 23 *** mean allelic diversity and heterozygosity observed among the provenances were similar to those from the native populations of *** in North ***’s genetic distance among the 23 was estimated and showed that a clear trend between geographic and genetic distances,indicating that some provenances have high genetic diversity with superior growth performance.

关键词： Introduction breeding Provenance test Adaptation Microsatellite marker Genetic distance

Improved Cycle Properties of FeS_2 Cathode Material with Metallic Additives

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材料科学与工程学报 2007年第6期25卷 910-913页

作者： Jae-won Choi Jae-Kwang kim Gouri Cheruvally Jou-Hyeon Ahn ki-won kim Hyo-Jun Ahn Dong-Kyu Park Department of Chemical & Biological Engineering and Engineering Research Institute Gyeongsang National University900 Gajwa-dongJinju660-701Korea School of Nano and Advanced Materials Engineering and Engineering Research Institute Gyeongsang National University900 Gajwa-dongJinju660-701Korea Kaya Advanced Material Art Inc. Baekrok-Ri 1010-1Yangsan 626-862Korea

Iron disulfide(FeS_2)cathode active material was prepared from iron and sulfur at room temperature by high energy mechanical *** FeS_2 composites containing Co or Ni transition metal powders as additives were also prepared by the same *** cells with these FeS_2 cathodes were studied for charge-discharge properties at room temperature using 0.5M LiTFSI in tetra(ethylene glycol)dimethyl ether(TEGDME)*** voltammetry showed two anodic oxidation peaks at 1.8 and 2.5V and two cathodic reduction peaks at 2.0 and 1.3 V for FeS_2 with metal *** addition of 5wt% Co and 3wt% Ni resulted in an enhancement of the first discharge capacity giving 571 and 844mAh/g respectively at *** cycle performance was also enhanced remarkably by the addition of these electrically conductive transition metals in the active ***_2 with 5wt% Co exhibited a stable cycle performance delivering a reversible capacity of 338mAh/g(37.8% of theoretical capacity)after 20 cycles.

关键词：阴极材料二硫化铁锂离子电池循环性能

Electrochemical Intercalation of Sodium into Silicon Thin Film

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材料科学与工程学报 2008年第1期26卷 141-144页

作者： Dong-Yeon kim Hyo-Jun Ahn Gyu-Bong Cho Jong-Seon kim Ho-Suk Ryu ki-won kim Jou-Hyeon Ahn won-Cheol Shin I-cube center nano advanced materials Engineering Gyeongsang National Uhiversity Jinju 660-701 Korea Department of Chemical ＆ Biological Engineering Gyeongsang National University J inju 660-701 Korea INOSTEK Inc Gyeonggi Technopark 1271-11 Sal-dong Sangnok-gu Ansan-si Gyeonggi-do 426-901 Korea

In order to investigate the possibility of Si thin film as an anode for Na battery,we studied the electrochemical intercalation of sodium into the Si *** Si thin film electrode was prepared using DC magnetron *** ion could intercalate into Si thin film upto Na0.52Si,i.e.530mAh·*** first discharge capacity was 80mAh·g-1-Si,which meant reversible amount of sodium *** discharge capacity slightly decreased to 70mAh·g-1-Si after 10 cycles.

关键词：钠插层反应电池硅薄膜电极直流电磁控溅射

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

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材料科学与工程学报 2007年第6期25卷 886-891页

作者： Kyo-Hong CHOI Kwon-Koo CHO Gyu-Bong CHO Hyo-Jun AHN ki-won kim Yoo-Young kim School of Nano & Advanced Materials Engineering ERI & i-cube centerGyeongsang National University900 GazwadongJinjuGyeongnam 660-701Korea Dept.of Mechanical Engineering Jinju National UniversityJinjuKorea

Several researches have been reported about the characteristic of β-Ga_2O_3 nanowires which was synthesized on nickel oxide *** indeed,recent researches about synthesis of β-Ga_2O_3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide *** this work,Gallium oxide(β-Ga_2O_3)nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700-1000℃ using the iron,nickel,copper,cobalt and zinc oxide as a catalyst,*** β-Ga_2O_3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850,900 and 950℃ in all the *** optimum experimental condition in synthesis of nanowires varied with the kind of *** increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods,and its diameter *** these results,we could be proposed that the growth mechanism of β-Ga_2O_3 nanowires was changed with synthesis temperature of *** and morphology of Synthesized nanowire was characterized by HR-TEM,FE-SEM,EDX and XRD.

关键词：金属纳米粒子显微结构镓氧化物形态学

Self-supported VO_(2)on polydopamine-derived pyroprotein-based fibers for ultrastable and flexible aqueous zinc-ion batteries

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Carbon Energy 2024年第7期6卷 1-13页

作者： Jeong Seok Yeon Sul ki Park Shinik kim Santosh VMohite won Il kim Gun Jang Hyun-Seok Jang Jiyoung Bae Sang Moon Lee won GHong Byung Hoon kim Yeonho kim Ho Seok Park School of Chemical Engineering College of EngineeringSungkyunkwan UniversityGyeonggi-doRepublic of Korea Department of Engineering University of CambridgeCambridgeUK Department of Applied Chemistry Konkuk UniversityChungjuRepublic of Korea Department of Chemistry Ulsan National Institute of Science and Technology(UNIST)College of Natural SciencesUlsanRepublic of Korea Department of Physics Incheon National UniversityIncheonRepublic of Korea Intelligent Sensor Convergence Research Center Incheon National UniversityIncheonRepublic of Korea Institute of Basic Science Incheon National UniversityIncheonRepublic of Korea Division of Material Analysis and Research Korea Basic Science InstituteDaejeonRepublic of Korea

A conventional electrode composite for rechargeable zinc-ion batteries(ZIBs)includes a binder for strong adhesion between the electrode material and the current ***,the introduction of a binder leads to electrochemical inactivity and low electrical conductivity,resulting in the decay of the capacity and a low rate *** present a binder-and conducting agent-free VO_(2)composite electrode using in situ polymerization of dopamine on a flexible current collector of pyroprotein-based *** as-fabricated composite electrode was used as a substrate for the direct growth of VO_(2)as a self-supported form on polydopamine-derived pyroprotein-based fibers(pp-fibers@VO_(2)(B)).It has a high conductivity and flexible nature as a current collector and moderate binding without conventional binders and conducting agents for the VO_(2)(B)*** addition,their electrochemical mechanism was *** energy storage is induced by Zn^(2+)/H^(+)coinsertion during discharging,which can be confirmed by the lattice expansion,the formation of by-products including Zn_(x)(OTf)_(y)(OH)_(2x−y)·nH_(2)O,and the reduction of V^(4+)to V^(3+).Furthermore,the assembled Zn//pp-fibers@VO_(2)(B)pouch cells have excellent flexibility and stable electrochemical performance under various bending states,showing application possibilities for portable and wearable power sources.

关键词： aqueous battery binder free conducting agent‐free flexible electrode zinc‐ion battery