• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.39-46
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• 1995

A complete form of physical optics solution to the E-polarized diffraction by a composite of conducting and dielectric wedges is obtained by sum ov geometrical optics solution and edge-diffracted field. The diffraction coefficients of the edge-diffracted field are expressed in series of cotangent functions. The electric field patterns of the physical optics solution are plotted in figures.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.819-823
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• 2009

• Current Optics and Photonics
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• v.8 no.2
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• pp.151-155
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• 2024

Optical systems often suffer from optical aberrations caused by imperfect hardware, which places significant constraints on their utility and performance. To reduce these undesirable effects, a comprehensive understanding of the aberrations inherent to optical systems is needed. This article presents an effective method for aberration detection using Zernike polynomials. The process involves scanning the object plane to identify the optimal focus and subsequently fitting the acquired focus data to Zernike polynomials. This fitting procedure facilitates the analysis of various aberrations in the optical system.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.3
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• pp.207-215
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• 2006

This study surveys the brand and design recognition by an expert vs. non-expert group in the eye glasses industry. This survey is to search for a way for domestic brands to compete and win foreign ones. The non-expert group chose design as the most noteworthy difference between domestic and foreign brands; likewise, the expert group appeared to first consider design on their choice. Brand recognition by the non-expert group appeared very low; on the other hand, expert group's recognition was higher with domestic brands than with foreign ones. In conclusion, the bounce back of domestic eye glasses business does not seem to be possible in a snap by a special recipe; rather, it is necessary to invest and make efforts to develop new techniques for better quality on the one hand, and to increase brand and design recognition on the other.

• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.200-204
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• 2008

Coherent tunable terahertz generation was demonstrated in periodically poled stoichiometric lithium tantalate crystal via difference frequency generation of femtosecond laser pulses. Simultaneous forward and backward terahertz radiations were obtained around 1.35 and 0.63 THz, respectively at low temperature. By cooling the crystal to reduce losses caused by phonon absorptions, the generated THz bandwidth was as narrow as 23GHz at the center frequency of 0.63 THz. The measurement result of temperature-dependent showed gradual intensity increase of the generated terahertz pulse and red shift of the center frequency as the temperature decrease from 291 to 143 K, but insignificant reduction of the spectral bandwidth. Furthermore, the stoichiometric crystal was very suitable for the suppression of THz loss at low temperature compared to the congruent $LiNbO_3$ crystal.

• Korean Journal of Optics and Photonics
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• v.17 no.2
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• pp.165-174
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• 2006

The autotstigmatic null lens system is designed and constructed for the fabrication of a parabolic mirror with the diameter of 450 mm(f/2.7). And the measurement reliability is also analyzed theoretically by means of the tolerancing technique using lens design software(CODE V). From this analysis, we can precisely fabricate a parabolic mirror with the large diameter of 450 mm(f/2.7). Meanwhile, in order to confirm the fabrication results by the autostigmatic method, the mirror surface is tested again by an autocollimating method that uses only a plane mirror without any null lens.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.179-180
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• 2009

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.695-696
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• 2004

• Proceedings of the Korean Magnestics Society Conference
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• 2009.12a
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• pp.197-198
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.633-634
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• 2008