• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.687-688
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.490-491
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.383-386
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• 2005

Low frequency heavy-weight impact noise is the most irritating noise in Korean high-rise reinforced concrete apartment buildings. This low frequency noise is generated by foot traffic due to the fact that Koreans do not wear shoes at home. The transmission of the noise is facilitated by a load bearing wall structural system without beams and columns which is used in these buildings. In order to control low frequency heavy-weight impact noise, floating floors using isolation materials such as glass-wool mat and poly-urethane mat are used. However, it was difficult to control low frequency heavy-weight impact sound using isolation material. In this study, reinforcement of concrete slab using beams and plate was conducted. Using the FEM analysis, the effect of concrete slab reinforcement using FRP(fiber-glass reinforced plastic) on the bang machine impact vibration acceleration level and sound were conducted at the standard floor impact sound test building. The $3{\sim}4dB$ floor impact vibration acceleration level and impact sound pressure level were reduced and the natural frequency of slabs were changed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.57-60
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• 2002

The high precision spindle is essential fer mass and low cost production of aspherical glass lens. Especially, in the grinding process of micro glass lens the performance of the spindle determine the machined surface quality. For the aspheric micro glass lens grinding, we design and make a high precision spindle. We use air bearings for high speed and low motion errors of the spindle. And the driving mechanism is an air turbine to remove heat generation. In this study, we make basic performance requirements of the spindle through benchmarking. And we confirm the requirements by basic machining test. We test air consumption, static stiffness, run-out and vibration of the spindle.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.254-257
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• 2001

An intensity-based optical fiber vibration sensor is applied to detect and evaluate damages and fiber failure of composites. The optical fiber vibration sensor is constructed by placing two cleaved fiber end, one of which is cantilevered in a hollow glass tube. The movement of the cantilevered section lags behind the rest of the sensor in response to an applied vibration and the amount of light coupled between the two fibers is thereby modulated. Vibration characteristics of the optical fiber vibration sensor are investigated. Surface mounted optical fiber vibration sensor is used in tensile and indentation test. Experimental results show that the optical fiber sensor can detect damages and fiber failure of composites correctly.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.728-732
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• 2008

This paper presents ion-based micro vibration sensor for the ultra-high frequency vibration detection. Presented sensor uses the motion of anion and cation in an electrolyte. Electrolyte vibration sensors have the high shock survival characteristics and a simple read-out circuit because of the small mass and own charges of ions. Presented sensor measures the induced electric potential by the mechanical-electrical coupling. It consist of electrolyte chamber and detection electrode. Electrolyte chamber was fabricated by PDMS molding. Detection electrode was made of gold evaporation on pyrex glass. Size of electrolyte chamber was designed as $600{\times}600{\times}100um$. Detection electrode had 200nm-thick and 42um-gap. In the experimental study, 5.8M sodium Chloride (NaCl) solution was used as electrolyte in 36nl-chamber. Mechanical vibration was measured from 2kHz to 4MHz.

• Journal of Conservation Science
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• v.38 no.2
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• pp.117-123
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• 2022

In this study, investigated the possibility of quantitatively and qualitatively analyzing Korean ancient glasses via Raman Spectroscopy. We subjected four categories of Korean traditional glasses, namely, lead-BaO, lead, potash, and soda glasses (3, 3, 10, and 10 pieces, respectively), to this analytical technique. The results showed significant differences between the stretching and bending Raman vibration regions corresponding to these different Korean ancient glass types. Specifically, the stretching vibration regions corresponding to lead-BaO and lead glasses showed peaks at 1040 and 1000 cm^-1, respectively; the stretching vibration region of normal glass appears at 1100 cm^-1. The bending vibration regions corresponding to potash and soda glass showed Raman peaks at 490 and 560 cm^-1, respectively. Furthermore, the Raman spectra of the lead and lead-BaO glasses showed red shifts, which depended on the amount of PbO present. Thus, our findings highlighted the possibility of quantitatively determining the amount of PbO, a major component of lead glasses, via Raman Spectroscopy.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.547-552
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• 2001

An intensity-based optical fiber vibration sensor is applied to detect and evaluate damages and fiber failure of composites. The optical fiber vibration sensor is constructed by placing two cleaved fiber end, one of which is cantilevered in a hollow glass tube. The movement of the cantilevered section lags behind the rest of the sensor in response to an applied vibration and the amount of light coupled between the two fibers is thereby modulated. Vibration characteristics of the optical fiber vibration sensor are investigated. Surface mounted optical fiber vibration sensor is used in tensile and indentation test. Experimental results show that the optical fiber sensor can detect damages and fiber failure of composites correctly.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.71.5-71
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• 2001

This paper presents the vibration control of a flexible intelligent beam with added mass. The materials which is a glass fiber reinforced(GFR) thermoplastic composite is employed to achieve vibration characteristics according to added mass induced end of composite beam. In the experiments of forced vibration control, the -controller are employed to achieve vibration suppression in forced vibration situations. Also, in the controller design, 1st and 2nd´s natural frequencies are considered in the modeling, because robust control theory which has robustness to structured uncertainty is adopted to suppress the vibration. By designing a controller using mu-synthesis, robust performance against measurement noise, various modeling.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.475-476
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• 2008

This paper is an experimental test for the close examination of breakdown causes of glass insulators using at the electric rail-road. The glass insulator is estimated the mechanical performance according to hitting test(ST-100, Sharp-Eng, KOR) that is based on KSC 3810. Insulators is damaged by pendulum weight at the steps of hitting angles. Glass and porcelain insulators are broken at the hitting angle of $72^{\circ}$. From the these results, glass insulator absorbed the impact from the pendulum weight but on the porcelain insulator, it is not transmitted vibration by impact. Hereafter, these results are expected that is used the data for the assessment on breakdown cause of a glass insulator.