• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1433-1436
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• 2007

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.237-242
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• 1998

A transparent and colorless $80SiO_2-20TiO_2$(mol%) thin films on soda-lime-silica slide glass and sapphire substrate were obtained by spin-coating technique using tetraethyl orthosilicate and titanium trichloride as starting materials. The prepared film annealed at $750^{\circ}C$ showed a high transmittance and a low reflectance. For the $SiO_2-TiO_2$ films on slide glasses, a strong interaction between the sodium ion and oxygens is properbly the origin of the good stability to the high temperature and the high humidity.

• Korean Journal of Optics and Photonics
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• v.2 no.3
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• pp.153-157
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• 1991

We report an analysis on the stability properties of external cavity semiconductor lasers exposed to strong feedback from an external grating. The frequency range of stable single mode oscillation is found to depend on the offset between the resonance frequency of the solitary laser and the frequency of maximum reflection from the grating.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1941-1944
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• 2004

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.695-698
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• 2012

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.731-734
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• 2009

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1321-1324
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• 2012

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.424-430
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• 2011

A novel T-type polyurethane 7 containing 1-(2,5-dioxyphenyl)-2-(5-(1,2,2-tricyanovinyl)-2-thienyl)ethenes as NLO chromophores, which constitute part of the polymer backbone, was prepared. Polyurethane 7 is soluble in common organic solvents such as DMF and DMSO. It shows a thermal stability up to $270^{\circ}C$ from TGA thermogram with $T_g$ value obtained from DSC thermogram near $155^{\circ}C$. The second harmonic generation (SHG) coefficient ($d_{33}$) of poled polymer film at 1560 nm fundamental wavelength is $3.56{\times}10^{-9}$ esu. Polymer 7 exhibits a thermal stability even at $5^{\circ}C$ higher than $T_g$, and no significant SHG decay is observed below $160^{\circ}C$, which is acceptable for nonlinear optical device applications.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.412-419
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• 2006

We design and fabricate an autostigmatic null lens system assembled in a fixed tube mount in order to evaluate the shape of an aluminum hyperbolic mirror with the diameter of 300 mm and the f-number of 1.98, which is fabricated by a high precision aspherical DTM (diamond turning machine). Also, we evaluate the degree of shape of the aspherical mirror by this autostigmatic null lens testing method. The autostigmatic null lens system assembling in a fixed tube mount has several advantages of light weight, good mechanical stability, etc. The permissible fabricating limits of null lenses and a mount are determined by considering various tolerances to assure the measurement reliability.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.83-92
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• 2015

Purpose: This study was performed to offer some more effective marketing strategies for optical shops on a basis of analyses of what lifestyles influence most on 'store selection' and 'recommendation intention' and of what properties of 'store selection' influence most on 'recommendation intention'. Methods: Questionnaire surveys were conducted from the customers who visited the optical shops in Seoul and northern Gyeonggi-do region from January 1 to June 30, 2014. It was analyzed via utilizing SPSS v.20.0 statistical package program. Results: The results in lifestyle-factors which influence on store selection were arranged in order as follows: 'stability oriented', 'goal oriented', 'cultural activity oriented'. And the results in value-factors which influence on 'recommendation intention' were arranged in order as follows: 'stability oriented', 'health oriented'. The most positive factor for 'recommendation intention' was revealed as 'dealing with customers' among several factors of 'store selection'. Conclusions: Today's marketing activities for customers should be suited for different lifestyles of customers. Customers who have 'stability oriented', 'goal oriented', and 'cultural activity oriented' lifestyles tend to select optical shops in consideration of 21 items when selecting an optical shop. Customers who have 'stability oriented', and 'health oriented' lifestyles have positive influences related to 'recommendation intention'. Also, it is likely for customers to recommend optical shops to others when the factor 'dealing with customers' meets their expectations.