• Journal of the Korean Society for Railway
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• v.10 no.2 s.39
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• pp.211-216
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• 2007

Rubber components are widely used in many application such as vibration isolators, damping, ride quality. Rubber spring is used in primary suspension system for railway vehicle. Characteristics and useful life prediction of rubber spring was very important in design procedure to assure the safety and reliability. Non-linear properties of rubber material which are described as strain energy function are important parameter to design and evaluate of rubber spring. These are determined by physical tests which are uniaxial tension, equi-biaxial tension and pure shear test. The computer simulation was executed to predict and evaluate the load capacity and stiffness for rubber spring. In order to investigate the useful life, the acceleration test were carried out. Acceleration test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful life prediction for rubber spring were proposed.

• International Journal of Railway
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• v.1 no.3
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• pp.122-127
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• 2008

Rubber components are widely used in many application such as vibration isolators, damping, ride quality. Rubber spring is used in primary suspension system for railway vehicle. Characteristics and useful life prediction of rubber spring was very important in design procedure to assure the safety and reliability. Non-linear properties of rubber material which are described as strain energy function are important parameter to design and evaluate of rubber spring. These are determined by physical tests which are uniaxial tension, equi-biaxial tension and pure shear test. The computer simulation was executed to predict and evaluate the load capacity and stiffness for rubber spring. In order to investigate the useful life, the acceleration test were carried out. Acceleration test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful life prediction for rubber spring were proposed.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.27-33
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• 2011

In general, the shear strength of a clay specimen under the direct shear test and the triaxial compression test increases with an increase in the shear rate. This study investigates the effects of shear rate and silt content on the stress-strain behavior of remolded Gwangyang clay, by changing the shear rate and the silt content. Based on the results of the triaxial compression tests, the equi-strain line of remolded Gwangyang clay shows initially positive slope and then becomes flat at certain strain level. As the strain level where the equistrain becomes flat is different depending on the soil with different silt contents, this can be considered as the inherent property of soil.

• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.65-81
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• 2003

The purpose of this study was to investigate the balance of stroke patient appling Task-Oriented Functional training program. Sixteen subjects were recruited from KeiMyung university Dongsan Medical Center inpatient satisfying requirement for this study. They were divided into Task-Oriented Functional training group and Conventional therapy group. They were measured by Sensory organization test and Motor control test items using EquiTest Version 8.0 machine before and after the test. The result of this study were to follow: 1. In Sensory organization test, there were no significant differences in static eguibrium score in both groups(p<.05). 2. In Sensory organization test, there were significant differences in dynamic eguibrium score in both groups(p<.05). 3. In Motor control test, there were significant differences in both groups(p<.05). 4. In exercise group, there were no significant differences in static Sensory organization test(p<.05). 5. In exercise group, there were significant differences in dynamic Sensory organization test(p<.05). 6. In exercise group, there were significant differences in Motor control test(p<.05). 7. In control group, there were no significant differences in static Sensory organization test(p<.05). 8. In control group, there were no significant differences in dynamic Sensory organization test(p<.05). 9. In control group, there were no significant differences in Motor control test(p<.05).

• Elastomers and Composites
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• v.42 no.1
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• pp.32-46
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• 2007

Mechanical properties of rubber material are very important in design procedure to assure the safety and reliability of the rubber components. In this paper, the material test and accelerated heat aging test were carried out. In order to investigate the effects of heat-aging on the material properties, hardness, elongation, stress-strain curves and dynamic characteristics were obtained from various test conditions. Also, rubber material coefficients were determined by both the uniaxical and equi-biaxial tensile tests.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.100-100
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• 2010

Because of power consumption increase, global wanning, and limitation of installation, not only high reliability and interruption capability but also compact and light power apparatuses are needed. To improve the insulation performance, the high E field concentration phenomena was considered. Breakdown mechanism in vacuum is different from that in other insulation materials. therefore, It is necessary to understand the electric field distribution and insulation characteristics. This paper discusses the simulation and LI(light impulse) test of the shield of outside vacuum interrupter As a result, FEM simulation and LI test show that improve distribution of electrical field and equi-potential line. due to external shield. in this case, outside shield induced electric field of triple junction point.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.923-931
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• 2008

Coupling rubber pad are important components in railway vehicles. It can be used for reduce shock, vibration and noise. Simple tension, equi-biaxial tension and pure shear test were performed to acquire the coefficient of rubber material which were Mooney-Rivlin and Ogden model. The finite element analysis was executed to evaluate the behavior of deformation and stress distribution by using the commercial finite element analysis code. Useful life evaluation are very important in design procedure to assure the safety and reliability of the rubber components. In this paper, useful life prediction of rubber pad for railway vehicle were experimentally investigated. Accelerated heat-aging test for rubber material were carried. Compression set results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.205-213
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• 2018

The purpose of this study was to investigate the effect of somatosensory input on the gait ability and equilibrium sensory of elderly women. The subjects who participated in this study were 31 elderly women with a mean age of 75 years or older who no using a walking stick and had no abnormality in otolaryngology. The control group consisted of 30 elderly women who did not exercise regularly more than twice a week. Dependent variables consisted of 2.44m timed up and go test, 10m usual gait, 10m fast gait and 6minute gait. The equilibrium sensory test was performed using EquiTest (NeuroCom, USA). The results of the study on gait ability were not statistically significant for 2.44m timed up and go test, and 10m usual gait. However, 10m fast gait (P<.001) and 6min gait (P<.05) showed significant differences. According to the results of the study on equilibrium sensory ability, there was no significant difference between Condition 1 and Condition 5 however Condition 2 (P<.01), Condition 3 (P<.01), Condition 4(P<.01) and Condition 6 (P<.05) showed statistically significant differences. In conclusion, walking stick have beneficial effects on walking and equilibrium sensation, and elderly women need to actively use walking stick when going out and walking.

• Economic and Environmental Geology
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• v.36 no.1
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• pp.49-58
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• 2003

To analyze the anisotropic characteristics of fractured aquifer, variations of streaming potential were measured during and after pumping over several wells at the two test sites. Surface electrical resistivity survey, normal resistivity logging, and slug test were performed at the wells to identify the hydrogeological structure. Applying the results to the recently suggested model, the aquifer of the two test sites showed confined characteristics. Anisotropic direction appeared in using equi-potential maps from self-potential monitoring results matched well with the results of the hydrogeological test. The self-potential monitoring method adopted in this study would be useful for providing a more reliable information on the anisotropy of aquifer in the pumping test at single well.

• Elastomers and Composites
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• v.47 no.3
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• pp.201-209
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• 2012

Grommet is one of the Automotive rubber components and is made from EPDM(Ethylene Propylene Diene monomer M-class) rubber and the nonlinear hyperelastic material properties of rubber are important to predict the behavior of rubber product. In this study, the stable stress-strain relations were obtained from the uni-axial tension test and the equi-biaxial tension test. Finite element analysis for grommet was carried out and heat aging test for the lifetime prediction of grommet was introduced.