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Design,Fabrication,and Analysis of Flapping and Folding Wing Mechanism for a Robotic Bird

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Journal of Bionic Engineering 2020年第2期17卷 229-240页

作者： Seung Wan Ryu Jong gu Lee Hyoun Jin kim Department of Mechanical&Aerospace Engineering and Automation Systems Research Institute Seoul National UniversitySeoul 08826Republic of Korea

Emulating periodic main wing movement of a bird for generating lift and thrust remains a significant challenge in developing a robotic *** sequences of main wing motion are comprised of flapping,folding,bending,and *** this paper,we concentrate on the flapping and folding motion,and design two wing mechanisms based on a 4-bar linkage structure:one is only for Flapping Motion(FM)and the other is for simultaneous Flapping and Folding Motion(FFM)during a wing *** derive relationships between length and angle of links to analyze kinematic characteristics of the mechanisms and conduct an optimization to select the length parameters of links that allow maximization of the flapping *** run a simulation to confirm the performance of the optimized parameters by examining physical properties,and fabricate two wing mechanisms *** particular,the folding motion is achieved without using an additional *** measurements to investigate a lift profile of each mechanism and their quantitative comparison of the performance of both types confirm the benefits of the folding motion in the perspectives of wing frequency and *** expect that our kinematic formulation,design procedures,and comparative measurement results can help develop a wing mechanism to create a truly biomimetic robotic bird.

关键词： biomimetic robotic bird flapping and folding wing mechanism wing kinematics force measurement

Simultaneous bilateral acromial base fractures after staged reverse total shoulder arthroplasty: A case report

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World Journal of Clinical Cases 2021年第1期9卷 284-290页

作者： Du-Han kim Beom-Soo kim chul-Hyun Cho Department of Orthopedic Surgery Keimyung University Dongsan HospitalKeimyung University School of MedicineDaegu 42601South Korea

BACKGROUND Acromial and scapular spine fractures after reverse total shoulder arthroplasty(RTSA)are a well-known complication that may negatively impact the effects of long-term ***,to the best of our knowledge,there has been no report of simultaneous bilateral fractures of the acromion or scapular spine that occurred following staged *** SUMMARY A 79-year-old right-handed male visited our outpatient clinic with a chief complaint of pain and limited motion of both shoulder joints for a one-year *** on plain radiographs and magnetic resonance images,the preoperative diagnosis was bilateral cuff tear arthropathy with failed rotator cuff *** patient was treated with staged bilateral RTSA at a two-month *** 5 and 3 mo after right and left side surgery,the patient returned to the outpatient clinic with severe pain and limited motion of both shoulder joints for 2 wk without a traumatic event.A computed tomography scan revealed nondisplaced acromial base fractures of both *** bilateral involvement,fracture location,and patient’s demand,open reduction and internal fixation(ORIF)using plate for bilateral acromial base fractures were *** 2 years after ORIF,the fracture was completely healed,and the patient was satisfied with shoulder *** This report describes an extremely rare case of simultaneous bilateral acromial base fractures after staged RTSA managed successfully by ORIF with a precontoured plate designed for distal clavicle *** acromial fracture after RTSA can be treated conservatively,simultaneous bilateral fractures may warrant surgical intervention as a means of addressing difficulties in activities of daily living.

关键词： Acromion Fracture Arthroplasty Shoulder Reverse total shoulder arthroplasty Case report Complication

Deep Drawing Process Using a Tractrix Die for Manufacturing Liners for a CNG High-Pressure Vessel(Type Ⅱ)

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Chinese Journal of Mechanical Engineering 2022年第1期35卷 132-143页

作者： gun‑Young Park Hyo‑Seo Kwak Hyo‑Seong Jang chul kim School of Mechanical Engineering Pusan National UniversityPusan 46241South Korea Department of Mechanical Engineering Dong-eui UniversityPusan 47340Korea.

The liner of a CNG pressure vessel is manufactured by a DDI(deep drawing and ironing)process for the cylinder part,which is a continuous process that includes a drawing process to reduce the diameter of the billet and a subsequent ironing process to reduce the thickness of the billet.A tractrix die used in the 1^(st) deep drawing allows the blank to flow smoothly by decreasing the punch load and radial tensile stress occurring in the *** also increases the draw ratio compared to conventional dies,but it causes forming *** this study,a shape coefficient(S_(c))is proposed for the tractrix die using the blank diameter(D_(0)),inflow diameter of the workpiece(d_(i)),and inflow angle of the workpiece(θ)for design of the tractrix *** effects of the thickness and inflow angle of the workpiece on wrinkling and folding were investigated through ***,a discriminant is proposed for the relative radial stress(σ)generated during the deep drawing process using the tractirx die and used to predict *** on the results,the blank thickness,the draw ratio,and the inflow of the workpiece angle in the 1^(st) deep drawing process are suggested,and the number of operations in the DDI process was reduced from 6 to *** improves the productivity and reduces the manufacturing cost.

关键词： Tractrix die Deep drawing Wrinkling Folding LDR(Limit draw ratio) FEM

Characteristics of Oxidation Reaction of Rare-Earth Chlorides in Eutectic Chloride Melt

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Journal of Rare Earths 2007年第S1期25卷 13-16页

作者： Yung-Zun Cho Hee-chul Yang Hee-chul Eun Eung-Ho kim In-Tae kim Advanced Fuel Cycle Process Development Korea Atomic Energy Research InstituteDaejeon 305-353Korea

Oxidation reaction of rare earth chlorides(Ce/Pr/Nd/EuCl3) in a LiCl-KCl eutectic molten salt was carried out using an oxygen sparging method. Regardless of the sparging time and the molten salt temperature, oxychlorides (NdOCl, PrOCl) and oxides(CeO, Eu2O3, PrO2) were formed as a oxidation products(i.e. precipitates) by the reaction with oxygen. The conversion efficiency of the rare earth elements to the precipitates increases with the sparging time and the molten salt temperature. In the conditions of 650 ℃ of a molten salt temperature and 420 min of a sparging time, the values of the conversion efficiency of the used rare earth chlorides were over 99.9%. Information on the hydrodynamics of an oxygen-molten salt two phase flow system is essential since its hydrodynamics strongly affect the oxidation reaction of rare earth elements in an eutectic chloride melts.

关键词： oxidation reaction oxygen sparging flow regime conversion efficiency rare earths

Thermal Dechlorination Kinetics of Rare Earth Oxychlorides

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Journal of Rare Earths 2007年第S1期25卷 8-12页

作者： Hee-chul Yang Yong-Zun Cho Hee-chul Eun Eung-Ho kim In-Tae kim Advanced Fuel Cycle Process Development Group Korea Atomic Energy ResearchInstituteDaejeon 305-353 Korea

The kinetics of a thermal dechlorination and oxidation of NdOCl and GdOCl were investigated by using a non-isothermal thermogravimetric analysis under various oxygen partial pressures. The conversions of NdOCl and GdOCl into each of their stable oxides (Nd2O3 and Gd2O3) appeared to be an oxygen-dependent endothermic and one-step reaction. The observed activation energy for the conversions of NdOCl and GdOCl were determined as 228.3±6.1 kJ·mole-1 and 137.7±4.1 kJ·mole-1, respectively. The conversions of NdOCl and GdOCl into each of their stable oxides (Nd2O3 and Gd2O3) could be described by a power law (g(α)=α3/2) and a linear-contracting boundary reaction (g(α)=α), respectively.

关键词： oxychloride dechlorination oxidation high temperature rare earths

Electromagnetically Induced Transparency in an Atom-Molecule Bose-Einstein Condensate

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Communications in Theoretical Physics 2007年第3X期48卷 461-464页

作者： JIN guang-Ri chul Koo kim Kyun Nahm Institute of Physics and Applied Physics Yonsei University Seoul 120-749 Korea Department of Physics Yonsei University Wonju 220-710 Korea

We propose a new measurement scheme for the atom-molecule dark state by using electromagnetically induced transparency （FIT） technique. Based on a density-matrix formalism, we calculate the absorption coefficient numerically. The appearance of the EIT dip in the spectra profile gives clear evidence for the creation of the dark state in the atom-molecule Bose--Einstein condensate.

关键词： electromagnetically induced transparency dark state Bose-Einsteln condensate

UBVVI Surface Photometry of the Spiral Galaxy NGC 300 in the Sculptor Group

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Chinese Journal of Astronomy and Astrophysics 2004年第4期4卷 299-310页

作者： Sang chul kim Hwankyung Sung Hong Soo Park Eon-Chang Sung Korea Astronomy Observatory Taejon 305-348Republic of KoreaDepartment of Astronomy and Space ScienceSejong University98 Gunja-dongGwangjin-guSeoul 143-747Republic of KoreaAstronomy ProgramSEESSeoul National UniversitySeoul 151-742Republic of KoreaKorea Astronomy ObservatoryTaejon 305-348Republic of Korea

We present UBVI surface photometry over a 20.5' × 20.5' area of the late-type spiral galaxy NGC 300. We have derived isophotal maps, surface brightness profiles, ellipticity profiles, position angle profiles, and color profiles. By merging our I-band measurements with those of Boker et al. based on Hubble Space Telescope observations, we have obtained combined I-band surface brightness profiles for the region 0.02' < r < 500' and have decomposed the profiles into three components: a nucleus, a bulge, and an exponential disk.

关键词： galaxies: spiral - galaxies: photometry - galaxies: individual(NGC 300) - galaxies: nuclei

Relief of YAP-mediated inhibition by IKKε promotes innate antiviral immunity

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Cellular & Molecular Immunology 2018年第6期15卷 642-644页

作者： Nayoung kim Yun-Yong Park chul Hyun Joo Hun Sik kim Department of Convergence Medicine Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505Korea Asan Institute for Life Sciences Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505Korea Department of Microbiology Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505Korea Department of Biomedical Sciences Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505Korea

The innate immune response to invading viruses is critical for the mounting of protective immunity,in which type I interferons(IFN),for example,IFN-αandβ,are potent effector molecules.1 Most cell types,particularly fibroblasts and epithelial cells,produce IFN-β,whereas hematopoietic cells,notably plasmacytoid dendritic cells,are the predominant sources of IFN-α.IFNs potently stimulate a variety of innate and adaptive immune cells,including macrophages,NK cells and T *** binding of type I IFN to its cognate receptor triggers the activation of the Janus kinase signal transducer and activator of transcription pathway,which results in the transcription of IFNstimulated genes that play key roles in host resistance to viral infections.

关键词： immunity protective mount

Multi-Stream CNN-Based Personal Recognition Method Using Surface Electromyogram for 5G Security

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Computers, Materials & Continua 2022年第8期72卷 2997-3007页

作者： Jin Su kim Min-gu kim Jae Myung kim Sung Bum Pan IT Research Institute Chosun UniversityGwangju61452Korea Interdisciplinary Program in IT-Bio Convergence System Chosun UniversityGwangju61452Korea

As fifth generation technology standard(5G)technology develops,the possibility of being exposed to the risk of cyber-attacks that exploits vulnerabilities in the 5G environment is *** existing personal recognitionmethod used for granting permission is a password-basedmethod,which causes security ***,personal recognition studies using bio-signals are being conducted as a method to access control to *** bio-signal,surface electromyogram(sEMG)can solve the existing personal recognition problem that was unable to the modification of registered information owing to the characteristic changes in its signal according to the performed ***,as an advantage,sEMG can be conveniently measured from arms and *** paper proposes a personal recognition method using sEMG,based on a multi-stream convolutional neural network(CNN).The proposed method decomposes sEMG signals into intrinsic mode functions(IMF)using empirical mode decomposition(EMD)and transforms each IMF into a *** recognition is performed by analyzing time–frequency features from the spectrogram transformed *** database(DB)adopted in this paper is the Ninapro DB,which is a benchmark EMG *** experimental results indicate that the personal recognition performance of the multi-stream CNN using the IMF spectrogram improved by 1.91%,compared with the singlestream CNN using the spectrogram of raw sEMG.

关键词： Personal recognition electromyogram signal multi-stream network empirical mode decomposition