• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.107-107
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• 2010

In this study, we have investigated the holographic grating formation on Ag-doped amorphous chalcogenide AsGeSeS thin films with Ag thickness. Ag/AsGeSeS thin films with the incident laser beam wavelength for the improvement of the polarization diffraction grating efficiency. Holographic gratings have been formed using Diode Pumped Solid State laser (DPSS, 532.0nm) under [P:P] polarized the intensity polarization holography. The diffraction efficiency was obtained by +1st order intensity. The result is shown that the diffraction efficiency of Ag/AsGeSeS double layer thin film for the Ag thickness, the maximum grating diffraction efficiency using 60nm Ag layer is 0.96%.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.246-246
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• 2010

In this paper, we investigated the diffraction grating efficiency on AsSeS and Ag-doped amorphous chalcogenide Ag/AsSeS thin film for used to volume hologram. The Chalcogenide film thickness was 0.5um and Ag thin film was varied from 10nm and 20nm. Diffraction efficiency was obtained from (P:P) polarized Diode Pumped Solid State laser(DPSS, 532.0nm: 200mW) beam on AsSeS and Ag/AsSeS thin films. As a results, diffraction grating was not formed at AsSeS thin film but at Ag-doped AsSeS thin film, diffraction grating was formed well compare with the former.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.762-765
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• 2014

We fabricated a periodically poled lithium niobate (PPLN) by direct laser-writing of a quasi-phase-matching (QPM) structure in photolithographic process. Because we do not need to prepare a photomask by electron-beam writing, the "maskless" process shortens the fabrication time and significantly reduces the cost. We evaluated the poling quality of the direct laser-written PPLN by measuring the diffraction noise from the surface relief pattern of the fabricated QPM grating and comparing the results to those from a conventional PPLN made with a photomask. The quality of the PPLN fabricated by direct laser-writing was shown to be equivalent to that fabricated by the conventional method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.197-197
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• 2009

We have investigated the holographic grating formation on Ag-doped amorphous chalcogenide AsGeSeS thin films with Ag thickness. Holographic gratings have been formed using Diode Pumped Solid State laser (DPSS, 532.0nm) under [P:P] polarized the intensity polarization holography. The diffraction efficiency was obtained by +1st order intensity.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1261-1267
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• 2003

On the basis of the distribution of particle size measured by laser diffraction spectrometers, this research was carried out to investigate the characteristics of mist removal with the change of operating condition in the plasma reactor of impulse streamer corona. The operating parameters in this experiment were power of impulse streamer corona, gas velocity, impulse generation time, gas temperature, and SOx/NOx concentration. The collection efficiency T(d) was estimated by the distribution of particle size in the collection zone through the advanced model.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.69-76
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• 1999

This research was carried but to investigate the characteristics of mist removal with the change of operating conditions in the plasma reactor of impulse streamer corona based on the distribution of particle size measured by laser diffraction spectrometers. The operating conditions in this experiment were power of impulse streamer corona, gas velocity, collection time, and SOx/NOx concentration. The collection efficiency T(d) was estimated by distribution of particle size in the collection zone through the advanced model.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.145-150
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• 1998

This study was carried out to investigate the loss amount of collection at the different of precipitatation time, high voltage and gas speed. This work has focused on the dependence of the collection efficiency in the collector zone with gas speed and high voltage. This advanced Model is developed by research of the different parameter as the conventionnal modem of study. In order to investigate collection efficiency of electrostatic precipitator, the loss amount of knocking was measured with Monitek-Treubung and the particle size was analyzed by He-Ne laser diffraction spectroscopy.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.179.2-179
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• 2003

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.429-430
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• 2008

We demonstrate coherent x-ray diffraction imaging using table-top x-ray laser at a wavelength of 13.9nm driven by 10-Hz ti:Sapphire laser system at the Advanced Photonics Research Institute in Korea. Since the flux of x-ray photons reaches as high as $10^9$ photons/pulse in a $20{\times}20{\mu}m^2$ field of view, we measured a ingle-pulse diffraction pattern of a micrometer-scale object with high dynamic range of diffraction intensities and successfully reconstructed to the image using phase retrieval algorithm with an oversampling ratio of 1:6. the imaging resolution is $^{\sim}150$ nm, while that is much improved by stacking the many diffraction patterns. This demonstration can be extended to the biological sample with the diffraction limited resolution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.163-168
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• 1994

Zinc coated steel sheets have been widely used in automotive industry. High power laser welding has been used as an excellent welding means for thin sheets. The welding residual stress, which was brought in laser welding, causes making weak the mechanical strength. The purpose of this study is to get the residual stress distribution in various laser welding condition by FEM and verify the results by X-Ray diffraction. Welding residual stresses have been calculated by thermal elasto-plastic analysis using finite element method. Form the results, it can be known that the laser welding condition affects to distribution of the residual stress.