• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.1-5
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• 2003

This paper presented the effects of accumulation of surface charges on hydrophobicity level and the surface states of silicone polymer used for outdoor insulator treated by ultraviolet irradiation and corona discharge through measuring surface voltage decay of a corona-charged specimen were investigated. The surface resistivity by the method of the surface potential decay was compared with the value by the three electrodes methods. From this study, it was found that the accumulation of surface charges above a critical surface voltage on silicone insulating materials could lead to the temporary loss of surface hydrophobicity. In addtion, uv stress lead to a longer decay time of surface charges. We could conclude that the effects of surface charges on hydrophocity level and the changes of surface state by various artificial treatments were understood through a trend of surface potential decay.

• International Journal of Concrete Structures and Materials
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• v.10 no.2
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• pp.249-256
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• 2016

This paper deals with the effects of silica fume content and polymer-binder ratio on the properties of ultrarapid-hardening polymer-modified mortar using silica fume and ethylene-vinyl acetate redispersible polymer powder instead of styrene-butadiene rubber latex to shorten the hardening time. The ultrarapid-hardening polymer-modified mortar was prepared with various silica fume contents and polymer-binder ratios, and tested flexural strength, compressive strength, water absorption, carbonation depth and chloride ion penetration depth. As results, the flexural, compressive and adhesion strengths of the ultrarapid-hardening polymer-modified mortar tended to increase as increasing polymer-binder ratio, and reached the maximums at 4 % of silica fume content. The water absorption, carbonation and chloride ion penetration resistance were improved according to silica fume content and polymer-binder ratio.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.126-129
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• 2009

In this study, it was aimed to develop the re-use technology of ultra-fine silicon powders, by-products during the current production process of high purity poly-Si feedstock. For this goal, the compacts of the silicon powders were tried to fabricate by CIP (Cold Isostatic Pressing) method using silicon rubber mold without chemical binder materials. The density ratio of the silicon powder compacts reached 74%. In order to simulate the actual handling and charging conditions of feedstock material in casting process, a shaking test was carried out and mass loss measured. Finally, the silicon powder compacts were melted using a cold crucible induction melting method and the purity assessment was conducted by Hall effect measurement.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.10
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• pp.766-772
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• 2002

In this investigation, experimental attempts were made to observe and determine the variations in elastic and damping properties of the PVC depending on the amounts of MBS added to the mixture, PVC/MBS, and also on the thicknesses of the specimens. An acoustic resonance technique was used for the tests In this investigation. It serves as a method to characterize properties of materials set in vibrational motions, which is initiated by low level stresses generated by externally supplied acoustic energy. Substantial variations were observed in the test results with the addition of the MBS to the PVC. It was found that the magnitudes of elastic constants decrease while the damping capacity improve when MBS rubber was added in the range up to 9 phr.

• 연구논문집
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• s.29
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• pp.83-90
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• 1999

In naval ships, pump machineries are the major sources of airborne and structure-borne noise. Noise is critical issue in ships not only it causes annoyance to crews, but also it can increase the underwater radiated noise, which is crucial in anti-submarine warfare. In present study, it is discussed the reduction of structure-borne noise of pump machineries by showing several examples. The most typical and effective solution is to use double resilient mount system. However, in cases where double resilient system cannot be applied due to space and weight increase, rubber pad can be used to reduce the structure-borne noise. In principle, the concept of structure-borne noise reduction is the same as that of vibration isolation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.447-450
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• 2002

Recently polymeric insulators and arresters are being used for outdoor high voltage applications. Polymeric insulators for transmission line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage(UHV) transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. Polymeric insulator kind are a relatively new technology, but their expected life is still unknown. In this paper, the material property for polymeric insulating material such as silicone rubber and EPBM is investigated by cross-link time and the relation between tracking resistance and W resistance is analyzed by IEC 60587 and W aging experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.34-34
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• 2010

This paper describes effect of the bending deformation of high voltage composite bushing with winding tension. The composite bushing can be formed, by adding silicone rubber sheds to a tube of composite materials. The FRP tube is internal insulating part of a composite bushing and is designed to ensure the mechanical characteristics. Generally the properties of FRP tube can be influenced by the winding angle, wall thickness and winding tension. As winding tension is increased glass contents was increased in the range of 70.4~76.6%. In the bending test, winding tension is increased residual deflection was decreased in the range of 14.0~12.2 mm.

• Journal of the Korean Society of Costume
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• v.64 no.5
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• pp.50-61
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• 2014

Fashion has been compared to art since Japanese avant-garde fashion designers expanded the thoughts about conceptual fashion in late 1970s. The fashion designers focused on the materiality of fashion textiles by placing more importance on it than the shapes. This bears a striking resemblance to contemporary art of 1960s and 1970s as many artists used soft materials like felt, fabric, rubber to emphasize themselves. This study establishes the materiality of fabric, which can be found in both contemporary art and fashion. The classification of materiality consists of flexibility, humanizing and temporality. In this work, there is a significant disparity between contemporary art and fashion.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.409-414
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• 2003

Power steering hose is device that operation oil passes between steering gear box and oil pump by parts that is used to do steering system. Because this hose is receiving heat and pressure of high temperature, leakage can produce swaging from hitch of steel materials of done part. In this paper, we analyze swaging process of Power steering hose by finite element analysis, and achieved thermal and pressure analysis with this shape. We can analogize weakness part of hose through this result, and examine closely oil leakage and rubber failure mechanism and look for important design benevolence of power steering hose development.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.135-140
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• 2013

Ultrasonic cutting is a kind of eco-technique and cost-effective technique to be used for cutting of various materials such as baked product, fresh/frozen food, rubber, textile, wood, bone, etc. The performance of ultrasonic cutting is affected by design of cutting horn and cutting conditions. Specially the design of horn to resonate at the longitudinal direction is most important. To analyze the problems from which cracking and noise are often generated with conventional cutting horn, FEA is carried out, and then improved cutting horn which can reduce maximum stress and stress concentration is designed. Vibration characteristics, resonant frequency, gain, and amplitude uniformity of the cutting horn designed optimally are evaluated through FFT analysis and compared with those of conventional cutting horn.