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A Comparative Study of Antifatigue Effects of Taurine and Vitamin C on Chronic Fatigue Syndrome

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Pharmacology & Pharmacy 2022年第8期13卷 300-312页

作者： Shin-Hee kim Hyun-Jin kim semi kim Ju-Seop Kang Young Tae Koo Sang Hun Lee Dong-Hyun Paik Medicine Park Co. Ltd. Seoul Republic of Korea Department of Pharmacology College of Medicine Hanyang University Seoul Republic of Korea Kwang-Dong Pharmaceutical Co. Ltd. Seoul Republic of Korea

Vitamin C and taurine (TR) are well known as active components for fatigue recovery. However, the mechanism of the anti-fatigue effects of vitamin C and TR is still unclear. Our study was designed to evaluate the anti-fatigue activities of vitamin C and TR in an animal test for fatigue and to compare the activities between vitamin C and TR. Materials and Methods: Vitamin C, TR or their combination were orally administrated to mice once daily for 15 days, and then metabolic activities such as blood glucose, triglyceride (TG), lactate, and lactate dehydrogenase (LDH) as well as antioxidant activities such as malondialdehyde (MDA) and superoxide dismutase (SOD) were determined (evaluated) after forced swimming test (FST). Results: Compared with the control group, C100, C200, and T50 showed a tendency to decrease mobility in FST. Moreover, TG (C100, C200, T200), LDH (C200), lactic acid (C100) and MDA (C50, C100, C200) levels were inhibited by vitamin C and TR. Conclusions: These results suggest that vitamin C and TR have anti-fatigue activities in mice, with vitamin C providing a stronger effect.

关键词： Vitamin C Taurine Chronic Fatigue Syndrome Anti-Fatigue Effect

Modeling asymmetric fracture mechanics of Mg alloy wire in drawing process

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Journal of Magnesium and Alloys 2024年第5期12卷 2057-2069页

作者： Sunghoon Choi Jongwon Shin Joung Sik Suh Dongchoul kim Department of Mechanical Engineering Sogang UniversitySeoul04107Republic of Korea Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during *** hexagonally close-packed crystal structure of Mg alloys causes asymmetric fracture behavior,especially in the compression *** aim of this study is to develop a comprehensive damage model for Mg alloy wire that accurately predicts ductile fracture,with a focus on the compression region.A novel experimental method was introduced to measure the ductile fracture of Mg alloy wires under different stress *** wire drawing process was simulated using the Generalized Incremental Stress-State dependent damage(GISSMO)Model and the semi-Analytical Model for Polymers(SAMP)*** damage model's prediction and the experimental results were found to be in excellent agreement,especially in determining crack *** analysis established a safe zone diagram for die angle and reduction ratio,and experimental validation confirmed the feasibility of this *** proposed damage model can provide a practical and reliable analysis for optimizing the drawing process of Mg alloy wire.

关键词： Mg alloy Wire drawing Finite element method Damage model Safe zone diagram

Re-visiting supersymmetric Janus solutions: a perturbative construction

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Chinese Physics C 2020年第7期44卷 43-54页

作者： Nakwoo kim Se-Jin kim Department of Physics and Research Institute of Basic Science Kyung Hee UniversitySeoul 02447Republic of Korea

We construct holographic Janus solutions,which describe a conformal interface in the theory of M2-branes,in four-dimensional gauged supergravities using a perturbative *** particular,we study three Einsteinscalar systems and their BPS equations,which are derived by Bobev,Pilch,and Warner(2014).The actions of our interest are all consistent truncations of D=11 supergravity,chosen to be invariant under SO(4)×SO(4),SU(3)×U(1)×U(1),and G2 symmetry subgroups of SO(8).The utility of our semi-analytic result is illustrated by the calculation of minimal area surface and the associated holographic entanglement entropy.

关键词： holography Janus solutions supergravity entanglement entropy

A systematic correlation between morphology of porous carbon cathode and electrolyte in lithium-sulfur battery

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Journal of Energy Chemistry 2021年第10期30卷 561-573,I0014页

作者： Jihyeon Park Seoyoung Yoon Seoyeah Oh Jiyoon kim Dongjun kim Geonho kim Jiyeon Lee Myeong Jun Song Ilto kim Kwonnam Sohn Jiwon kim School of Integrated Technology College of EngineeringYonsei University85 Songdogwahak-roYeonsu-guIncheon 21983Republic of Korea Integrated Science and Engineering Division Underwood International CollegeYonsei University85 Songdogwahak-roYeonsu-guIncheon 21983Republic of Korea Integrated Biotechnology and Translational Medicine Graduate SchoolYonsei University85 Songdogwahak-roYeonsu-guIncheon 21983Republic of Korea LG Chem. LG Science Park30 Magokjungang 10-roGangseo-guSeoul 07796Republic of Korea

Porous carbon has been applied for lithium-sulfur battery cathodes,and carbonized metal-organic framework(MOF)is advantageous in tuning the ***,we have systematically synthesized water-distorted MOF(WDM)derived porous carbon via controlling the proportion of both water in a mixed solvent(dimethylformamide and water)and ligand in MOF-5 precursors(metal and ligand),which is categorized by its morphology(*** stone(closed),Tassel(open)and Intermediate(semi-open)).For example,decrease in water and increase in ligand content induce Cracked stone WDMs which showed the highest specific surface area(2742-2990 m^(2)/g)and pore volume(2.81-3.28 cm^(3)/g)after *** effect of carbonized WDMs(CWDMs)on battery performance was examined by introducing electrolytes with different sulfur reduction mechanisms(***/DME and ACN_(2) LiTFSITTE):Closed framework effectively confines polysulfide,whereas open framework enhances electrolyte *** initial capacities of the batteries were in the following order:Cracked stone>Intermediate>Tassel for DOL/DME and Intermediate>Tassel>Cracked stone for ACN_(2) *** note,Intermediate CWDM exhibited the highest initial capacity and retained capacity after 100 cycles(1398 and 747 mAh/g)in ACN_(2) LiTFSI-TTE electrolyte having advantages from both open and closed *** sum,we could correlate cathode morphology(openness and pore structure)and electrolyte type(*** solubility)with lithium-sulfur battery performance.

关键词： Lithium-sulfur battery Metal-organic framework Hierarchical porous carbon cathode Morphology control Electrolyte Lithium polysulfide solubility

A flexible, robust, and high ion-conducting solid electrolyte membranes enabled by interpenetrated network structure for all-solid-state lithium metal battery

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Journal of Energy Chemistry 2022年第5期31卷 603-611页

作者： Zhenchuan Tian Dukjoon kim School of Chemical Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea

Poly(vinyl alcohol)/poly(ethylene glycol)(PVA/PEG) semi-interpenetrating networks(s-IPN) were synthesized for the application of solid electrolyte membranes of lithium metal batteries. Thermal, mechanical and dimensional stability, lithium-ion conductivity, interfacial compatibility, and cell performance were evaluated to assure their application. As this s-IPN structure suppressed the crystallinity by formation of network structure, both the lithium-ion conductivity and mechanical strength were simultaneously enhanced. The PVA/PEG-3s-IPN showed the highest lithium-ion conductivity of 3.26 × 10^(-4)S cm^(-1)in a wide electrochemical window(5.8 V vs. Li/Li^(+)), maintaining the robust solid-state with the tensile strength beyond 16.2 MPa at room temperature. The synthesized solid electrolyte membranes exhibited quite high specific capacity over 122 m Ah g^(-1)at 0.1 C from Li|PVA/PEG-3s-IPN|LiFePO_(4) cell and the long-term stable lithium stripping/plating performance for 1000 cycles from Li symmetric cell.

关键词： Solid polymer electrolyte Lithium battery semi-IPN Lithium-ion conductivity

Acoustic band gaps in two-dimensional square arrays of semi-hollow circular cylinders

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Science China(Technological Sciences) 2009年第2期52卷 303-312页

作者： T. kim MOE Key Laboratory for Strength and Vibration School of Aerospace Xi'an Jiaotong University

Concave surfaces focus sound while convex surfaces disperse sound. It is therefore interesting to know if it is possible to make use of these two opposite characteristics to enhance the band gap performance of periodic arrays of solid cylinders in air. In this paper, the band gap characteristics of a 2-D square array of semi-hollow circular cylinders embedded in air are investigated, both experimentally and theoretically. In comparison with the types of inclusion studied by previous researchers, a semi-hollow circular cylinder is unique in the sense that it has concave inner surfaces and convex outer surfaces. The finite difference time domain (FDTD) method is employed to study the propagation behavior of sound across the new phononic crystal of finite extent, and the influences of sample size and inclusion orientation on band gap characteristics are quantified in order to obtain the maximum band gap. For reference, the band gap behaviors of solid circular cylinder/air and hollow circular cylinder/air systems are considered and compared with those of semi-hollow circular cylinder/air systems. In addition to semi-hollow circular cylinders, other inclusion topologies such as semi-hollow triangular and square cylinders are also investigated. To validate the theoretical predictions, experimental measurements on square arrays of hollow Al cylinders in air and semi-hollow Al cylinders in air are carried out. The results demonstrate that the semi-hollow circular cylinder/air system has the best overall band gap performance.

关键词： phononic crystals PDTD semi-hollow circular cylinders band gaps experimental verification

A semi-analytical method for forced vibration analysis of cracked laminated composite beam with general boundary condition

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Journal of Ocean Engineering and Science 2021年第1期6卷 40-53页

作者： Sok kim Kwanghun kim Myongchol Ri Yongsong Paek Choljun kim Department of Information Engineering Chongjin Mine&Metal UniversityChongjin 999091Democratic People’s Republic of Korea Department of Engineering Machine Pyongyang University of Mechanical EngineeringPyongyang 999093Democratic People’s Republic of Korea Institute of Science Pyongyang University of Mechanical EngineeringPyongyang 999093Democratic People’s Republic of Korea Department of Resources Development Mechanical Engineering Pyongyang University of Mechanical EngineeringPyongyang 999093Democratic People’s Republic of Korea

In this paper,a semi-analytical method for the forced vibration analysis of cracked laminated composite beam(CLCB)is *** computational model is formulated by Timoshenko beam theory and its dynamic solution is solved using the Jacobi-Ritz *** boundary conditions(BCs)at both ends of the CLCB are generalized by the application of artificial elastic springs,the CLCB is separated into two elements along the crack,the flexibility coefficient of fracture theory is used to model the essential continuous condition of the connective *** the allowable displacement functions used to analyze dynamic characteristics of CLCB are expressed by classical Jacobi orthogonal polynomials in a more general *** accuracy of the proposed method is verified through the compare with results of the finite element method(software ABAQUS is used in this paper).On this basis,the parametric study for dynamic analysis characteristics of CLCB is performed to provide reference datum for engineers.

关键词： semi-analytical method Cracked laminated composite beam(CLCB) Dynamic analysis General boundary condition Numerical analysis

Design of low noise airfoil with high aerodynamic performance for use on small wind turbines

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Science China(Technological Sciences) 2010年第1期53卷 75-79页

作者： Taehyung kim Seungmin LEE Hogeon kim Soogab LEE Department of Mechanical and Aerospace Engineering Seoul National University599 Gwanak-roGwanak-guSeoul 151-742Republic of Korea

Wind power is one of the most reliable renewable energy sources and internationally installed capacity is increasing radically every *** wind power has been favored by the public in general,the problem with the impact of wind turbine noise on people living in the vicinity of the turbines has been *** noise wind turbine design is becoming more and more important as noise is spreading more adverse effect of wind turbine to *** paper demonstrates the design of 10 kW class wind turbines,each of three blades,a rotor diameter 6.4 m,a rated rotating speed 200 r/min and a rated wind speed 10 m/*** optimized airfoil is dedicated for the 75% spanwise position because the dominant source of a wind turbine blade is trailing edge noise from the outer 25% of the *** computations are performed for incompressible flow and for Mach number at 0.145 and for Reynolds numbers at 1.02×106 with a lift performance,which is resistant to surface contamination and turbulence *** objectives in the design process are to reduce noise emission,while sustaining high aerodynamic *** broadband noise sources are predicted by semi-empirical formulas composed of the groundwork by Brooks et *** Lowson associated with typical wind turbine operation *** the airfoil redesign process,the aerodynamic performance is analyzed to reduce the wind turbine power *** results obtained from the design process show that the design method is capable of designing airfoils with reduced noise using a commercial 10 kW class wind turbine blade airfoil as a ***,the new optimized airfoil showing 2.9 dB reductions of total sound pressure level(SPL) and higher aerodynamic performance are achieved.

关键词： wind turbine aerodynamic noise airfoil self noise low noise airfoil design

Laser-assisted deposition of Cu bumps for microelectronic packaging

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中国有色金属学会会刊：英文版 2012年第S3期22卷 683-687页

作者： Won-Seok CHOI Joohan kim Department of Nano IT Fusion Program Seoul National University of Science and Technology Department of Mechanical and Automotive Engineering Seoul National University of Science and Technology

Cu bump was transferred using a focused laser pulse for microelectronic *** Nd:YAG laser pulse (maximum energy of 500 mJ;wavelength of 1064 nm;fluences of 0.4-2.1 kJ/cm2) was irradiated on a sacrificial absorption layer with copper *** focused laser beam induced plasma between the semi-transparent donor slide and the sacrificial layer,causing a shock *** shock wave pressure pushed the Cu layer and transferred material to deposit a bump on substrate.A beam-shaper was used to produce uniform pressure at the interface to reduce fragmentation of the transferred material on the *** calculated shock wave pressure with respect to laser fluence was 1-3 GPa.A Cu bump of diameter of 200 μm was successfully deposited at laser fluence of 0.6 kJ/cm *** pressure control at the sacrificial layer using a laser pulse was critical to produce a bump with less *** technique can be applied to forming Cu bump for an interconnecting process in electronics.

关键词： laser induced forward transfer bump deposition Nd:YAG pulsed laser micro system packaging beam shaping