• Proceedings of the KSR Conference
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• 2003.05a
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• pp.493-498
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• 2003

Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. For these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I ). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.159-164
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• 2020

The response analysis of frame structure with open section beams considering warping conditions and short duration load have been performed. When a beam of frame structure is subjected under torsional moment, the cross section will deform a warping as well as twist. For some thin-walled sections warping will be large, and accompanying warping restraint will induce axial and shear stresses and reduce the twist of beam which stiffens the beam in torsion. Because of impact or blast loads, the wave propagation effects become increasingly important as load duration decreases. This paper presents that a warping restraint in finite element model effects the behavior of beam deformation, dynamic mode shape and response analysis. The computer modelling of frame is discussed in linear beam element model and linear thin shell element model, also presents a correlation between computer predicted and actual experimental results for static deflection, natural frequencies and mode shapes of frame. A method to estimate the number of normal modes that are important is discussed.

• Journal of Korean Physical Therapy Science
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• v.9 no.4
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• pp.169-176
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• 2002

The kinesiologic electromyograhy(KEMG) is one of the most common use in physical therapy for understanding normal function and dysfunction of the neuromuscular system. Physical therapists concerned to patterns of muscle response, position, type of muscle contraction, onset and cessation of activity, the level of muscle response in relation to effort, and type of muscle contraction. Also they are use KEMG to assess the exercises for facilitate or for inhibit specific muscle activity. However there is a few references that provide information of KEMG Thus, the purpose of this article is for the use and interpretation of KEMG data. This article will guide beginning researchers for collecting, managing and analyzing of KEMG data.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.343-350
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• 1999

The purpose of this study is to compare the response of the high-strength concrete beam-column-slab subassembly with the response of a normal-strength concrete specimens. Four assemblies were designed 2/3 scale beam-column-slab joint(fc'=240kg/cm2 fc'=700kg/cm2) and tested to investigate seismic behaviour. From the test results 1) flexral cracks emerge to inside of bean deeply for high strength concrete member 2) the high-strength specimens represented stable hysteretic behaviour for the displacement ductility 5.5 but degradation in stiffness and strength and unstable hysteretic behaviors were observed owing to the brittleness of high-strength concrete beyond its range.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.60-64
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• 2004

Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. for these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II.

• Advances in nano research
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• v.17 no.3
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• pp.221-234
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• 2024

In this paper, dynamic response of annular nanoplates in improving sports equipment with surface effect embedded by visco Pasternak fractional foundation is studied. Size effects are evaluated by modified couple stress theory (MCST) and the surface effects are considered by the Gurtin-Murdoch theory. The structural damping effect is considered in this research using Kelvin-Voigt model. Sinusoidal shear deformation theory (SSDT) is applied for mathematical modelling of the nanostructure system. The numerical procedure of differential quadrature (DQ) is presented to determine the dynamic deflection as well as dynamic response of the annular nanoplates. The numerical results dynamic deflection of the nanostructure is considering, including material length scale parameter, spring and damper constants of visco-pasternak fractional foundation, geometrical parameters of annular nanoplates, surface stress effects.

• Toxicological Research
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• v.21 no.2
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• pp.115-119
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• 2005

In the present study, we evaluated the free radical scavenging and xanthine oxidase inhibitory activities exhibited by extracts obtained from the dried stems (and leaves) of Lespedeza bicolor We also assessed its potential irritation activities with regard to cosmetic use. When the DPPH radical scavenging activities of L. bicolor were assessed at six different concentrations (0, 50, 100, 250, 500 and 1000 ${\mu}g/ml$), the concentration of L. bicolor required to inhibit DPPH radical formation by $50\%$ was found to be $164.90{\mu}g/ml$. The effects of L. bicolor on the inhibition of xanthine oxidase were determined at seven different concentrations. The $50\%$ effective concentration was found to be $282.75{\mu}g/ml$. In the skin irritation test, all animals survived for the duration of the study, and all exhibited normal gains in body weight. The control sites exhibited no response to the control procedures. No edema, erythema, or eschar formation was observed in any of the tested rabbits. In the ocular irritation study, all of the rabbit eyes remained normal. In summary, L. bicolor extracts were considered to be non-irritating to the skin and eye.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.4
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• pp.147-157
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• 2010

Objectives : The study is performed to investigate the influence of psychological stress on neck muscles tone and heart rate variability(HRV). Methods : This study was carried out with the data from stress response index score(SRI), surface electromyography(sEMG) and HRV. First subjects were divided into two group according to the SRI points. Subjects in group A had points of SRI in which lower than 30 points. Subjects in group B had points of SRI in which higher than 30 points. Then we investigated how to difference of the index of sEMG and HRV according to each groups. Results : In this study, the muscle contraction of both upper trapezius muscle in stress group were higher than non-stress group significantly. Complexity, root mean square of successive differences of R-R intervals(RMSSD), standard deviation difference between adjacent normal to normal intervals(SDSD), high frequency oscillation power(Ln(HF)), normalized HF(Norm HF) in stress group were lower than non-stress group significantly and normalized LF(Norm LF) was higher. Conclusions : This results show that the stress was associated with neck muscle condition and autonomic nervous system.

• Journal of Veterinary Clinics
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• v.16 no.1
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• pp.203-209
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• 1999

A 4-year-old female Shih-tzu with severe episcleral congestion and buphthalmos in left eye was referred to the Veterinary Teaching Hospital, Chonnam National University in October 1998. During two months in local veterinary clinics, the dog had been treated unsuccessfully with tarsorrhaphy and antibiotics. By history taking, cause of the glaucoma was ascertained as accidental nonpenetrated cornea trauma by owner, Ophthalmic examination revealed that the left eye was buphthalmic with severe episcleral congestion, pain and fever. The direct pupillary light response could not be evaluated in the left eye, but right eye had normal reaction. The intraocular pressure was 4.5 mmHg in the right eye and 33 mmHg in the left eye, as measured with a Schiotz tonometer, Ultrasonographic finding revealed hyperechoic vitrous body and central echofree material. The Schirmer tear test showed 20 mm in the left eye and 8 mm in the right eye. The hematologic examination revealed monocytosis. The initial medical treatment was admitted, but there was no response. Transpalpebral enucleation in the left eye under inhalation anesthesia with enflurane 1.2 vol% in oxygen was performed. The day after operation the left eye ravealed no exudate, and pain, and the systemic vital signs were normal. The prognosis is excellent.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.3.2-3.2
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• 2011

Nanofibers, one of various one-dimensional nanomaterials such as nanorods, nanowires and nanotubes have been successfully synthesized by many groups in recent years and their applications to chemical sensors, catalytic filters and biomedicine, etc. are extensively tested. In particular, there is a possibility that chemical sensors based on oxide nanofibers can overcome the shortcomings of chemical sensors based on single nanowires. In order to prepare oxide nanofibers, the electrospinning method is most widely used. In this work, we synthesized various oxide nanofibers including ZnO, SnO2 and CuO by employing an electrospinning method and various shapes of nanofibers including core-shell nanofibers and hollow nanofibers as well. The response properties of the various nanofibers to oxidizing and reducing gaseous species have been investigated systematically. The normal oxide nanofibers showed high sensitivity and quite fast response time to many gaseous species. Furthermore, derivatives of normal nanofibers including hollow nanofibers, core-shell nanofibers and heterostructured nanofibers display much superior sensing properties. These results hold promise for the practical application of oxide nanofibers to chemical sensors. In addition, the sensing mechanisms operated in the nanofibers will be discussed in detail.