• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.114-115
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• 2005

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2006.11a
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• pp.152-153
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• 2006

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2010.10a
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• pp.133-134
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• 2010

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.21-22
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• 2016

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.311-317
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• 2019

We first numerically analyzed the characteristics of a silicon-based grating structure for beam steering. The analysis includes the basic principle of the grating structure according to the wavelength, peak radiation angle, radiation efficiency, and full-width at the half maximum(FWHM) of the radiation angle. Based on the analysis, we propose a silicon-based grating structure integrated with distributed Bragg reflector(DBR) to obtain a high radiation efficiency and narrow beam width simultaneously. We performed the numerical optimization of the radiation efficiency and FWHM of the radiation angle according to the DBR position. By the design optimization using the proposed grating structure compatible with the complementary metal-oxide semiconductor(CMOS) process, we achieved a maximum radiation efficiency of 87.1% and minimum FWHM of radiation angle of $4.68^{\circ}$.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.7 s.124
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• pp.596-604
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• 2007

This article investigates the effects of geometric configuration on the vibro-acoustic characteristics of in-plane vibration of a thick annular disc. Disc thickness and outer radius for a given inner radius are selected as independent variables having reasonable ranges. Variations in structural eigensolutions for radial modes are investigated using pre-developed analytical method. Based on these data, far-field sound pressure distributions due to the modal vibrations for a given geometry are also calculated using an analytical solution. Modal sound powers and radiation efficiencies are calculated from the far-field sound pressure distributions and vibratory velocity distributions on the radial surfaces. Based on the results explained above, the geometric configuration that minimizes modal sound radiations in a given frequency range is determined. Finally sound power and radiation efficiency spectra for a unit harmonic force from the selected geometric configuration are obtained from structural and acoustic modal data using the modal expansion technique. Multi-modal sound radiations of the optimized disc that are obtained using proposed analytical methods are confirmed with numerical results. Using the procedure introduced in this article, sound radiation due to in-plane modes within a specific frequency range can be minimized by the disc geometry modifications in a comprehensive and convenient manner.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2007.05a
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• pp.215-216
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• 2007

원전에서 발생하는 중 저준위방사성폐기물(이하, "방폐물"이라 함)을 처분시설로 운반하는 것은 원전과 처분시설이 임해지역에 위치하고 있으므로 육상운반보다는 선박을 이용하는 해상운반이 효율적이다. 해상운반은 무엇보다 다량운반이 가능하며 이로 인하여 운반회수가 줄고, 인구밀집지역을 지나지 않아도 되기 때문에 방폐물의 운반에 대한 위험도가 상대적으로 적어 안전성 확보에 유리하다. 방폐물의 해상운반은 운반 도중 방사성물질의 위험으로부터 인간과 환경을 보호하기 위하여 국제원자력기구(IAEA)의 안전운반규정, 국제해사기구(IMO)의 국제해상위험물규칙, 국내 원자력법 등 국내외의 엄격한 기술기준에 따라 안전성이 철저하게 보장되어야만 한다. 한국수력원자력(주)(이하, "한수원"이라 함)는 원전(월성원전 제외)에서 처분시설까지 방폐물을 안전하고 효율적으로 운반하기 위하여 전용운송선박, 운반용기, 전용운반차량 및 원전 물량장 등으로 이루어지는 해상운반시스템을 구축하여 운영할 것이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.372-376
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• 2014

This study is on acoustic radiation efficiency of a tiffened cylindrical model in water-multi-excitation with phase difference using commercial numerical program ABAQUS and SYSNOISE. When the stiffened cylindrical model is under multi-excitation with phase difference, the surface vibration field is variated with phase difference of excitation. By this different surface vibration field, the acoustic radiation efficiency is also variated with phase difference of excitation.

• The Journal of the Acoustical Society of Korea
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• v.42 no.2
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• pp.83-93
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• 2023

Trapezoidal corrugated plates are often treated as orthotropic plates to simplify the modelling of the corrugation. However, this simplification is not valid at high frequencies in which the localized vibration within the parts of corrugation takes place. In this study, the vibrational and acoustical characteristics of corrugated plates are investigated up to high frequencies by means of the wavenumber domain numerical approach. Based on the findings from this numerical analysis, an approximate method to predict vibro-acoustic characteristics of corrugated plates is proposed. This approximate model consists of four equivalent plates which can represent global and local behaviours of corrugated plates. The radiation efficiency of corrugated plates is predicted from the approximate model and validated through the comparison with those of the numerical method.

• Journal of Biomedical Engineering Research
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• v.22 no.2
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• pp.205-210
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• 2001

The effectiveness of extracorporeal shock wave lithotripter for the therapy of calculus has been well known in the field of urology. There are many studies about the performance of that and the influence into human body. Among them, it is an impertant issue that cavitation is always deal with shock wave. A medium of the shock wave is related to the cavitation phenomenon. In this paper, therefore, we analysis the spectra of radiated sounds and the break efficiency on focal region due to the medium of shock wave. The results show that the cavitation bubbles produce a harmful on the break efficiency and the stability of the radiated sounds due to the ESWL.