• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.221-223
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• 1996

The test on the breakdown strength and the electrical conduction property about the PET flim have been done when the interface exist and do not exist between the PET flim. The PET flim that does not exist the interface uniformly maintained the breakdown strength as the temperature increase. But, the breakdown strength of the PET flim inserted carbon black flim decreased as the temperature increase. The initial current of the PET flim inserted carbon black flim was higher than the PET flim and the uniformly distributed between 2.2E-9 and 2.5E-9 above 5kV/mm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.156-159
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• 2000

In this paper, the physical and electrical properties of epoxy composites are investigated at boiling absorption condition to observe the influences of moisture. Also, in order to improve water resistance of matrix resin, IPN method was introduced and the influence was investigated. In order to analyze the basic physical properties of samples, scanning electron microscopy method was utilized, and impulse voltage dielectric strength was measured. As a result, it was verified that, in case of IPN samples, the ratio of moisture absorption was decreased due to the improvement of adhesion strength, and impulse voltage dielectric strength of SN sample was degraded abruptly as boiling time and filler content were increasing, while IPN samples were slowly degraded due to the improvement of adhesion strength.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.429-432
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• 2004

The demand for electric power keeps growing, and tends to be more effective. Polymer insulators have been manufactured for almost twenty years and the excellent insulation performance of polymer insulators is attractive. Polymeric materials are now widely used as a replacement for inorganic materials such as porcelain or glass for the outdoor insulation of high voltage insulation. GFRP has been used widely as a core materials for polymer insulators. This paper reports the mechanical properties of GFRP for insulators. The bending strength was simulated and evaluated according to the winding angle. The fiber orientation in GFRP has a great effect on the strength of GFRP because the strength of GFRP mainly depends on the strength of fiber. Results of simulated and evaluated strength of GFRP were compared each other. The simulated strength of GFRP rod was different from the evaluated strength. It was caused that the shear stress had a great effect on the strength of GFRP although the stress of parallel direction of GFRP was much higher.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.586-588
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• 2001

Inner part of FRP specimen was made unidirectionally by pultrusion method and outer part of FRP was made by filament winding method to study the effect of fiber orientatons on the strength of FRP. The strength of bending and compression was simulated and evaluated. The results of simulated strength and evaluated strength were different greately each other. The stress which affect the feature of FRP was simulated to investigate the difference of the results between simulation and evaluation Shear stresses were investigated to the main stress to affect the fracture of FRP.

• Electrical & Electronic Materials
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• v.9 no.3
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• pp.265-269
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• 1996

We have studied the effect of the mesogenic core of nematic liquid crystals (NLCs) for polar (out-of-plane tilt) anchoring strength and surface order parameter on rubbed polyimide (PI) surfaces. The order of polar anchoring strength for NLCs on rubbed PI surfaces is 5CB > PCH5 > CCH5. From the above results, we suggest that the polar anchoring strength depends on the polarizability of the NLCs. The surface order parameter for NLCs is 5CB > PCH5 > CCH5 on rubbed PI surfaces. We conclude that the polar anchoring strength is strongly related to the surface order parameter on rubbed PI surfaces.

• Electrical & Electronic Materials
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• v.5 no.4
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• pp.393-399
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• 1992

In order to increase the coupling strength between bisphenol-A type epoxy resin and filler SiO$_{2}$ it was treated to filler with silane coupling agent[KBM-603]. To observe how silane coupling agent effects on dielectric breakdown strength of Epoxy/SiO$_{2}$ compound material, specimens of eight type were made like following. (A-1, A-2), (B-1, B-2), (C-1, C-2), (D-1, D-2) (see 2-2. Specimen) Specimen treated with silane coupling agent had always bigger dielectric breakdown strength than non-treated specimen. Under the influence of silane coupling agent, increment ratio of dielectric breakdown strength at specimen manufactured by hand drill was very bigger than that of specimen inserted spherical electrode. Therefore, as the specimen shape was varied, it was studied on effect that silane coupling agent affects on dielectric breakdown strength of Epoxy/SiO$_{2}$ compound material.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.780-785
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• 2014

To assess the deterioration condition of stator insulation, diagnostic and AC dielectric strength tests were performed on five high voltage (HV) motors (2,000 HP, 6.6 kV) for boiler feed-water pump (BFP). Two HV motors for BFP were installed per unit. Following the long term rewinding program, the diagnostic test was performed on five 6.6 kV motors during the planning maintenance period. After completing diagnostic test, AC dielectric strength test was done on the stator windings of HV motors. The AC dielectric strength test was conducted at 15 kV for one minute. Dielectric strength test and diagnostics test results confirmed that the stator insulation was judged to be in serviceable condition in the five 6.6 kV motors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.239-242
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• 1999

In this study, we evaluates the dependence of thickness and temperature in the breakdown strength of MDPE and effect of semiconductor. As the result, breakdown strength trend to decrease according to the increase of thickness and temperature but there is no dependence of temperature in the 70${\mu}{\textrm}{m}$ MDPE film. We obtained the result that the breakdown strength was a little lower in the structure of Semil/MDPE than Semi/MDPE/Semi, but breakdown strength of MDPE was greater both of all. Therefore we are investigating the effect of semiconductor in the breakdown strength.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.16 no.1
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• pp.20-25
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• 2010

Purpose : To compare the effect between isometric exercise group(n=10) and electrical stimulation therapy group(n=10) on improvement of biceps brachii muscle strength. Methods : The experiments were performed for 4 weeks and three times a week. The participants of this study were 20 students(10 male, 10 female) who had not any medical problems. We divided into the two groups. One group received isometric exercise and the other group received EST for 4 weeks. The biceps brachii muscle strength was evaluated by making use of the KIN-COM. Results : The results were as follows 1. One group which received isometric exercise increased 36% for biceps brachii muscle strength. 2.The other group which received EST increased 54% for biceps brachii muscle strength. Conclusion : The results of this study showed that EST group was more effective than isometric exercise group.

• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.32-39
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• 2021

Objective: The weakness of muscle strength due to stroke affects the posture control and gait in the patients with stroke. Stroke This study examined the effects of the stair climbing training with functional electrical stimulation on muscle strength, dynamic balance, and gait in individuals with chronic stroke. Design: Randomized controlled trial. Methods: Total forty-eight patients were randomly assigned to the 3 groups. Participants randomly divided to stair climbing training with functional electrical stimulation group (SCT+FES group, n=16), stair climbing training group (SCT group, n=16) and control group (n=16). Subjects in the SCT+FES group and SCT group performed stair walking training with and without functional electrical stimulation for 30 minutes, 3 sessions per week for 4 weeks and all subjects received conventional physical therapy for 30 minutes with 5 sessions per week for 4 weeks. Outcome measurements were assessed using the sit-to stand Test for strength, timed up and go test and modified-timed up and go test for dynamic balance, and 10m walk test and GaitRite system for gait. Results: In the SCT+FES group, subjects have been shown the significant increase in lower extremity strength (p<0.05), significantly improve in dynamic balance (p<0.05), and significantly improve in their temporal gait parameter (p<0.05). The SCT+FES group was significantly better than other groups in all parameters (p<0.05). Conclusions: This result suggested that the SCT+FES may be effective strategy to improve muscle strength, dynamic balance, and gait for individuals with chronic stroke.