• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.7
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• pp.600-605
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• 2001

The electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photo-aligned with polarized UV exposure on various blending photopolymer surfaces were investigated. Excellent LC alignment and voltage-transmittance (V-T) characteristics for TN-LCD photo-aligned with polarized UV exposure of normal incidence on the blending photopolymer (polyimide (PI) +PM4Ch(poly(4-methacryloyloxy chalcone))) surface containing chalcone group can be achieved. The EO performances for the TN-LCD photo-aligned on the blending photopolymer can be improved due to the photosensitivity by long side chain of the photopolymer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.5
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• pp.430-434
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• 2001

We synthesized a new photo-crosslinkable polymer (polyimide (PI)-chalcone-biphenyl (BP)) and liquid crystal (LC) aligning capabilities for nematic (N) LC with obliquely polarized UV exposure on a photo-crosslinkable polymer were studied. The high pretilt angle in NLC was obtained by polarized UV exposure on a PI-Chal-BP surface for 3 min. The high pretilt angle generated in NLC is attributed to the biphenyl moieties and the photo-dimerized chalclone group of a photopolymer. Also, good thermal stability of a PI-Chal-BP were obtained by thermogravimetric analysis (TGA) measurement until 450$^{\circ}C$. Finally, good voltage-transmittance curves and response time were observed by UV exposure on a PI-Chal-BP surface for 3min.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.137-140
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• 2000

Synthesis of a new copoly (M4Ch-ChMA), copoly ((4-methacryloyloxy) chalcone-cholestery methacrylate), with chalconyl and cholesteryl moiety characteristics for photoalignment materials was investigated. Good thermal stabilities of the synthesized copolymers are confirmed by thermogravimetric analysis (TGA) measurement. The pretilt angles of the nematic liquid crystal (NLC) are reduced as UV exposure time is increased on the copolymer surfaces. A pretilt angle of 81$^{\circ}$ in NLC was observed with UV exposure of 3 min on the copolymer-3 surface. The NLCs pretilt angle is attributable to increased chalcone with increasing the UV exposure time.

• Journal of dental hygiene science
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• v.5 no.4
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• pp.227-231
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• 2005

To provide basic data necessary to develop an efficient sealant project as a public oral health project, this study applied a sealant through a photodimerization method to first-graders from public primary schools in the Dong-gu Health Center in Incheon and conducted a survey on favor and knowledge of the sealant project with their parents and, consequently, obtained the following results. 1. 84.7% of the parents knew a sealant and most of them got the knowledge from a dental clinic (35.7%) or a school (31.6%). 2. A large majority of respondents (86.2%) were satisfied with sealant application; many parents (75.8%) checked for maintenance of the sealant; and 75.6% demanded reexamination after sealant application. 3. As factors associated with acceptance of a sealant, high recognition of a sealant, much experience of visiting a dental clinic, and parents' great concern about children's dental health were related to high sealant application. To put the results together, it is desirable to develop the sealant project by the Dong-gu Health Center in Incheon actively as a public oral health project.