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Miniaturized Twin-legged Robot with an Electromagnetic Oscillatory Actuator

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Journal of Bionic Engineering 2018年第1期15卷 106-113页

作者： Buhyun Shin youngshik kim Jamie Paik kyung-min Lee Department of Mechanical Engineering Hanbat National University 125 Dongseodaero Yuseong-gu Daejeon 34158 Republic of Korea The Institute of Mechanical Engineering EPFL BM 4118 Station 17 1015-Lausanne Switzerland School of Mechanical Engineering Yeungnam University 280 Daehak-Ro Gyeongsan Gyeongbuk 38541 Republic of Korea

There have been many studies on the moving mechanism of micro robots, such as stick-slip, inchworm like motion, and impact drive. Novel actuators like lead zirconate titanate （PZT）, Shape Memory Alloy （SMA）, magnetostrictive materials, electromagnetic actuators, electoractive polymers, ultrasonic linear motors, and dielectric elastomers are utilized to realize the moving mechanism. The use of a conventional electromagnetic actuator is unfavorable, because of a few drawbacks, such as generation of stray magnetic fields, hard to miniaturize to the millimeter scale because of 3D integration and a scaling law, and power consumption to maintain a certain position. This research presents a micro robot that uses an electromagnetic actuator customized and developed for micro robot. The electromagnetic actuator is designed from a Brushless Direct Current （BLDC） motor to overcome the drawbacks mentioned above. The developed robot is composed of two electromagnetic actuators. The overall size of the robot is 20 mm × 11 mm× 9 mm （length × height × width） and the weight is 3 g. The developed robot is able to move bidirectionally with a maximum moving speed of 15.76 mm·s︿-1 （0.79 body-length per second）. The optimal conditions of an input signal are calculated theoretically and verified with experiments.

关键词： electromagnetic actuator oscillatory actuator bionic micro robot stick-slip brushless DC motor

A GIS-Based Framework for Real-Time Debris-Flow Hazard Assessment for Expressways in Korea

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International Journal of Disaster Risk Science 2016年第3期7卷 293-311页

作者： Han-Saem kim Choong-Ki Chung Sang-Rae kim kyung-Suk kim Earthquake Research Center Korea Institute of Geoscience and Mineral Resources Department of Civil and Environmental Engineering Seoul National University Department of Civil and Environmental Engineering Northwestern University Expressway and Transportation Research Institute Korea Expressway Corporation

Debris flows caused by heavy rainfall in mountain areas near expressways lead to severe social and economic losses and sometimes result in ***, the development of a real-time system for debris-flow hazard assessment is necessary to provide preliminary information for rapid decision making about evacuations or restoration measures, as well as to prevent secondary disasters caused by debris flows. Recently,various map-based approaches have been proposed using multi-attribute criteria and assessment methods for debrisflow susceptibilities. For the macrozonation of debris-flow hazard at a national scale, a simplified method such as the Korea Expressway Corporation(KEC) debris-flow hazard assessment method can be applied for systematic analysis based on geographic information systems(GIS) and monitoring networks. In this study, a GIS-based framework of real-time debris-flow hazard assessment for expressway sections is proposed based on the KEC debris-flow hazard assessment method. First, the KEC-based method was standardized in a systematic fashion using Arc GIS,enabling the objective and quantitative acquisition of various attribute datasets. The quantification of rainfall criteria also was considered. A safety management system for debris-flow hazard was developed based on the GIS platform. Finally, the method was applied and verified on three expressway sections in Korea. The grading standard for each individual influencing attribute was subsequently modified to more accurately assess the debris-flow hazards.

关键词： Debris-flow hazard Expressway management GIS Korea Real-time hazard assessment

Prenatal and postnatal factors associated with sudden infant death syndrome:an umbrella review of meta-analyses

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World Journal of Pediatrics 2024年第5期20卷 451-460页

作者： Tae Hyeon kim Hyeri Lee Selin Woo Hayeon Lee Jaeyu Park Guillaume Fond Laurent Boyer Jong Woo Hahn Jiseung Kang Dong Keon yon Department of Medicine Kyung Hee University College of MedicineSeoulSouth Korea Center for Digital Health Medical Science Research InstituteKyung Hee University College of MedicineSeoulSouth Korea Department of Regulatory Science Kyung Hee UniversitySeoulSouth Korea Department of Biomedical Engineering Kyung Hee UniversityYonginSouth Korea CEReSS-Health Service Research and Quality of Life Center Assistance Publique des Hôpitaux de MarseilleAix-Marseille UniversityMarseilleFrance Department of Pediatrics Seoul National University College of MedicineSeoulSouth Korea Department of Pediatrics Seoul National University Bundang HospitalSeongnamSouth Korea Department of Anesthesia Critical Care and Pain MedicineMassachusetts General Hospital14913th StreetRoom 4140CharlestownBostonMAUSA Division of Sleep Medicine Harvard Medical SchoolBostonMAUSA Department of Pediatrics Kyung Hee University Medical CenterKyung Hee University College of Medicine23 Kyungheedae-roDongdaemun-guSeoul02447South Korea Department of Precision Medicine Kyung Hee University College of MedicineSeoulSouth Korea

Background Comprehensive quantitative evidence on the risk and protective factors for sudden infant death syndrome(SIDS)effects is *** investigated the risk and protective factors related to *** We conducted an umbrella review of meta-analyses of observational and interventional studies assessing SIDS-related ***/MEDLINE,Embase,EBSCO,and Google Scholar were searched from inception until January 18,*** extraction,quality assessment,and certainty of evidence were assessed by using A Measurement Tool Assessment Systematic Reviews 2 following PRISMA *** to observational evidence,credibility was graded and classified by class and quality of evidence(CE;convincing,highly suggestive,suggestive,weak,or not significant).Our study protocol was registered with PROSPERO(CRD42023458696).The risk and protective factors related to SIDS are presented as equivalent odds ratios(eORs).Results We identified eight original meta-analyses,including 152 original articles,covering 12 unique risk and protective factors for SIDS across 21 countries/regions and five *** risk factors,including prenatal drug exposure[eOR=7.84(95%CI=4.81–12.79),CE=highly suggestive],prenatal opioid exposure[9.55(95%CI=4.87–18.72),CE=suggestive],prenatal methadone exposure[9.52(95%CI=3.34–27.10),CE=weak],prenatal cocaine exposure[4.38(95%CI=1.95–9.86),CE=weak],prenatal maternal smoking[2.25(95%CI=1.95–2.60),CE=highly suggestive],postnatal maternal smoking[1.97(95%CI=1.75–2.22),CE=weak],bed sharing[2.89(95%CI=1.81–4.60),CE=weak],and infants found with heads covered by bedclothes after last sleep[11.01(95%CI=5.40–22.45),CE=suggestive],were *** the other hand,three protective factors,namely,breastfeeding[0.57(95%CI=0.39–0.83),CE=non-significant],supine sleeping position[0.48(95%CI=0.37–0.63),CE=suggestive],and pacifier use[0.44(95%CI=0.30–0.65),CE=weak],were also *** Based on the evidence,we propose several risk and protecti

关键词： Infant Protective factor Risk factor Sudden infant death syndrome Umbrella review

K2Ti6O13 Nanoparticle-Loaded Porous rGO Crumples for Supercapacitors

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Nano-Micro Letters 2020年第1期12卷 115-123页

作者： Chongmin Lee Sun kyung kim Hankwon Chang Hee Dong Jang Department of Nanomaterials Science and Engineering University of Science and TechnologyYuseong‑guDaejeon 34113Republic of Korea Resources Utilization Research Center Korea Institute of Geoscience and Mineral ResourcesYuseong‑guDaejeon 34132Republic of Korea

One-dimensional alkali metal titanates containing potassium,sodium,and lithium are of great concern owing to their high ion mobility and high specific surface *** those titanates are combined with conductive materials such as graphene,carbon nanotube,and carbon nanofiber,they are able to be employed as efficient electrode materials for *** hexa-titanate(K2Ti6O13,KTO),in particular,has shown superior electrochemical properties compared to other alkali metal titanates because of their large lattice parameters induced by the large radius of potassium ***,we present porous rGO crumples(PGC)decorated with KTO nanoparticles(NPs)for application to *** KTO NP/PGC composites were synthesized by aerosol spray pyrolysis and post-heat *** NPs less than 10 nm in diameter were loaded onto PGCs ranging from 3 to 5μ*** porous structure of the composites was obtained by the activation of rGO by adding an excessive amount of KOH to the *** KTO NP/PGC composite electrodes fabricated at the GO/KOH/TiO2 ratio of 1:3:0.25 showed the highest performance(275 F g−1)in capacitance with different KOH concentrations and cycling stability(83%)after 2000 cycles at a current density of 1 A g−1.

关键词： Potassium hexa-titanate Porous graphene crumples Supercapacitors

Single-atom Pd catalyst anchored on Zr-based metal-organic polyhedra for Suzuki-Miyaura cross coupling reactions in aqueous media

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Nano Research 2021年第2期14卷 486-492页

作者： Seongsoo kim Seohyeon Jee kyung Min Choi Dong-Sik Shin Division of Chemical and Bioengineering Kangwon National UniversityGangwon-do 24341Republic of Korea Department of Chemical and Biological Engineering Sookmyung Womens University100 Cheongpa-ro 47-gilYongsan-guSeoul 04310Republic of Korea

The challenge for single-atom catalysts in various C-C cross coupling reaction exists in the development of solid supporting *** has been desired tofind a supporting material designed in molecular level to anchor a single-atom catalyst and provide high degree of dispersion and substrate access in aqueous ***,we prepared discrete cages of metal-organic polyhedra anchoring single Pd atom(MOP-BPY(Pd))and successfully performed a Suzuki-Miyaura cross coupling reaction with various substrates in aqueous *** was revealed that each tetrahedral cage of MOP-BPY(Pd)has 4.5 Pd atoms on average and retained its high degree of dispersion up to 3 months in *** coupling efficiencies of the Suzuki-Miyaura cross coupling reaction exhibited more than 90.0%for various substrates we have tested in the aqueous media,which is superior to those of the molecular Pd complex and metal-organic framework(MOF)anchoring Pd ***,MOP-BPY(Pd)was successfully recovered and recycled without performance degradation.

关键词： metal-organic polyhedra Suzuki-Miyaura cross coupling reaction structure characterization aqueous phase reaction high-degree of dispersion

Aging Behavior of Mg-Y-Zr and Mg-Nd-Zr Cast Alloys

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Journal of Materials Science & Technology 2008年第1期24卷 80-84页

作者： Yang-Do kim Nam-Hyun Kang Il-Guk Jo kyung-Hyun kim In-Bae kim School of Materials Science and Engineering Pusan National University 30 Jangjun-dongGeumjeong-guBusan 609-735Korea Deptartment of Materials Engineering Korea Institute of Machinery & Materials 66 Sangnam-dongChangwonGyeongsangnam-do 641-010Korea

Aging behavior of Mg-3.6Y-0.5Zr and ***-0.5Zr alloys was investigated by microhardness measurement and transmission electron *** the case of Mg-Y-Zr alloy,the presence ofβ″phase,a major strength- ener,having base centered orthorhombic structure with its lattice constants of a-（β″）=0.64 nm,b-（β″）=2.22 nm, and c-（β″）=0.52 nm was *** the case of Mg-Nd-Zr alloy aged at 250℃,the presence ofβ″andβ′phases was *** crystal structure ofβ″phase was found to be DO-（19） and its orientation relationships with Mg matrix were [0001]-（β″）//[0001]-（Mg） and [01（？）0]-（β″）//[01（？）0]-（Mg）.Theβ′phase had face centered cubic structure and its orientation relationships with Mg matrix were [011]-（β′）//[0001]-（Mg） and [（？）1（？）]β′//[（？）110]）-（Mg）. The ***-0.5Zr alloy showed higher hardness compared with Mg-3.6Y-0.5Zr alloy.

关键词： Mg-Y-Zr alloy Mg-Nd-Zr alloy Precipitation sequence

Stability of neodymium:YAG laser posterior capsulotomy in eyes with capsular tension rings

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International Journal of Ophthalmology(English edition) 2023年第6期16卷 891-896页

作者： Yang kyung Cho Min Sun kim Department of Ophthalmology St.Vincent’s HospitalCollege of MedicineThe Catholic University of KoreaSeoul 06591Republic of Korea

·AIM: To evaluate the stability of neodymium(Nd):YAG laser posterior capsulotomy in eyes with capsular tension rings(CTRs).·METHODS: A total of 60 eyes that underwent cataract surgery and laser posterior capsulotomy postoperatively were included in this retrospective cohort study. To evaluate the safety and stability of capsulotomy, changes in the size of posterior capsulotomy and anterior chamber depth(ACD) in three groups: the group without CTR, the group with 12 mm CTRs, and the group with 13 mm CTRs, at 1wk, 3, 12, and 15mo after capsulotomy, were compared. ·RESULTS: In the group without CTR and the group with 12 mm CTR, there was no significant change in ACD at every post-laser follow-up. In the group with 13 mm CTR, the ACD change was significant until 3mo after capsulotomy. In all groups, there was a significant increase in the area of capsulotomy between 1wk and 3mo post-laser. Between 3 and 12mo post-laser, only the group with 13 mm CTR showed a significant increase in the area of capsulotomy(P<0.01). ·CONCLUSION: Laser posterior capsulotomy is safe in all three groups. The capsulotomy and ACD become stabilized and have not shown significant changes since 1y postlaser, even with larger CTRs. The maintenance of centrifugal capsular tension can last longer with larger CTRs, and the stability of the capsulotomy site can be reached about 12mo after capsulotomy in pseudophakic eyes with larger CTRs.

关键词： Nd:YAG laser capsulotomy capsular tension ring

Small RNA- and DNA-based gene therapy for the treatment of liver cirrhosis, where we are?

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World Journal of Gastroenterology 2014年第40期20卷 14696-14705页

作者： kyung-Hyun kim Kwan-Kyu Park Department of Pathology College of Medicine Catholic University of Daegu Daegu 705-718 South Korea

Chronic liver diseases with different aetiologies rely on the chronic activation of liver injuries which result in a fibrogenesis progression to the end stage of cirrhosis and liver *** on the underlying cellular and molecular mechanisms of a liver fibrosis,there has been proposed several kinds of approaches for the treatment of liver ***,liver gene therapy has been developed as an alternative way to liver transplantation,which is the only effective therapy for chronic liver *** activation of hepatic stellate cells,a subsequent release of inflammatory cytokines and an accumulation of extracellular matrix during the liver fibrogenesis are the major obstacles to the treatment of liver *** targeted strategies have been developed,such as antisense oligodeoxynucleotides,RNA interference and decoy oligodeoxynucleotides to overcome this *** this report an overview will be provided of targeted strategies for the treatment of liver cirrhosis,and particularly,of the targeted gene therapy using short RNA and DNA segments.

关键词： Liver cirrhosis Gene therapy Oligodeoxynucleotides Antisense Small interfering RNA Micro RNA Decoy

Relationship between early structural changes at cornea incision sites and surgical outcomes after phacoemulsification

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International Journal of Ophthalmology(English edition) 2019年第7期12卷 1139-1145页

作者： kyung Hyun Jin Tae Gi kim Department of Ophthalmology Kyung Hee University Medical Center Kyung Hee University Seoul 02447 Korea Department of Ophthalmology Kyung Hee University Hospital at Gangdong Kyung Hee University Seoul 05278 Korea

AIM: To assess the early structural changes at clear corneal cataract incision sites and surgical outcomes using anterior segment optical coherence tomography(AS-OCT).METHODS: We evaluated 80 eyes of 59 patients who underwent phacoemulsification with a clear corneal incision. All incisions were evaluated 1 wk, 1, and 3 mo postoperatively using AS-OCT and analyzed regarding angle, length of the incision, maximal corneal thickness at the incision, and if present, corneal endothelial gap length and incision gap area. The patients were divided into two groups according to whether or not an endothelial gap was present at 1 wk postoperatively(endothelial gap, group 1;no endothelial gap, group 2). We analyzed the difference in patient and surgical factors between the two groups, and compared the surgical outcome and the refractive ***: An endothelial gap was observed in 56(70.0%) of 80 eyes at 1 wk postoperatively but not at 3 mo postoperatively. The mean patient age was significantly higher in group 1 than in group 2. The longer the length of the corneal incision and the steeper the incision angle, the greater the length and area of the endothelial gap. In group 1, the mean change in mean keratometry of the anterior cornea was significantly greater than in group 2, and the spherical equivalent(SE) and mean numerical error indicated significant myopic changes at 1 wk postoperatively. CONCLUSION: The risk of an endothelial gap increases with patient age and a long corneal incision and steep incision angle. The presence of an endothelial gap aftersurgery may affect the early postoperative corneal curvature and SE.

关键词： corneal incision structure phacoemulsification corneal curvature corneal endothelial gap anterior segment optical coherence tomography