• Journal of the East Asian Society of Dietary Life
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• v.15 no.2
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• pp.207-212
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• 2005

To determine changes of chlorophyll and potato glycoalkaloid(PGA) contents in potato tubers after lightening, Dejima potatoes cultivated in Korea were used and PGA was analyzed by HPLC. Potatoes were stored under fluorescent and UV light exposure or darkness for 7 days at $5^{\circ}C$. The contents of chlorophyll and glycoalkaloid in the peel of potatoes exposed to fluorescent light were increased to $84\%,\;69.5\%$ respectively compared to potatoes stored without lightening. While a marked effect of lightening on the peel of potatoes exposed to fluorescent light, UV light lead to no change of chlorophyll and less increase in glycoalkaloid than fluorescent did. The increase of chlorophyll was provoked by only fluorescent light. Cortex part did not accumulate any chlorophyll or glycoalkaloid.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.336-339
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• 2000

Effects of liquid crystal (LC) alignment using an in-situ photo-alignment method by linearly polarized UV exposure during imidization of polyirnide (PI) on the two kinds of PI surfaces with side chain were investigated. The generated pretilt angle in nematic (N) LC using an in-situ photo-alignment method was smaller than that of a conventional photo-alignment method for short UV exposure time. Also, the pretilt angle of the NLC using an in-situ photo-alignment method increases with increasing UV exposure time on the two kinds of the PI surfaces. Finally, the pretilt angle of NLC can be improved by annealing treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.835-838
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• 2000

A new photo-alignment material, copoly (PM4Ch-ChMA), copoly (poly (4-methacryloyloxy) chalcone-cholesterol methacrylate) was synthesized and the electro-optical (EO) characteristics for the photo-aligned vertical-aligned (VA)-LC display (LCD) were studied. Good voltage-transmittance (V-T) and response time characteristics for the photo-aligned VA-LCD with polarized UV exposure on the copolymer-1 (2%) surfaces for 1 min. were observed. EO performance for the photo-aligned VA-LCD decreased with increasing UV exposure time on a copolymer surface. Also, excellent V-T and response time characteristics for the photo-aligned VA-LCD with UV exposure on copolymer-2 and copolymer-3 surfaces for 3min. can be achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.358-361
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• 2001

A new photoalignment material PM15CA, poly{N-(phenyl)maleimide-co-3-[4-(pentyloxy) cinnamate]propyl-2-hydroxy-1-methacrylate}, was synthesized and the electro-optical (EO) characteristics in the vertical-aligned (VA) liquid crystal display (LCD) photo-aligned on the photopolymer surface were studied. Excellent voltage-transmittance(V-T) characteristics in the VA-LCD photoaligned with polarized UV exposure of oblique direction on the pohotopolymer surfaces for 1 min can be achieved. The transmittance of the VA-LCD photoaligned on the photopolymer surface decreased with increasing UV exposure time. We suggest that the decrease of transmittance in the VA-LCD photoaligned on the photopolymer surface is attributed to the dissociation of the ester linkage in the photodimerized cinnamate structure with increasing UV exposure time

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.502-505
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• 2003

We synthesized high thermal photoalignment material with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the photopolymer surface can be obtained. However, the low pretilt angles were obtained below $1^{\circ}$. The Voltage-transmittance (V-T) curve without backflow bounce in the photoaligned TN cell with UV exposure was observed. The response time of photoaligned TN cell was measured about 24 ms.

• Journal of the Optical Society of Korea
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• v.5 no.1
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• pp.16-19
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• 2001

A photopolymer, copoly (M4Ch-ChMA), copoly ((4-methacryloyloxy) chalcone-cholesteryl methacrylate), was synthesized in this study. The electro-optical (EO) characteristics for the photo-aligned vertical-alignment (VA)-liquid crystal display (LCD) were investigated. Excellent voltage-transmittance curves for the VA-LCD photo-aligned by polarized UV exposure on the copoly (M4Ch-ChMA) surface were observed. The response time for the photo-aligned VA-LCD decrease with increasing UV exposure time. consequently, the photo-dimerized chalcone moiety increased with increasing UV exposure time, which then contributed to a low response time for the VA-LCD photo-aligned.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.51-54
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• 2005

Light Guide Plate (LGP) of LCD-BLU(Back Light Unit) is manufactured by forming optical pattern with $5\~100um$ in diameter on the LGP by means of sand blasting or etching method. However, in order to improve the luminance of LCD-LGP, the design of optical pattern has introduced UV inclined-exposure process in this study. This micro-optical pattern, which has asymmetric elliptical column shaped pattern, can change low viewing-angle to high viewing-angle, as well as it contribute to diffusion of light. As a result, this type of micro-optical pattern can introduce the highly luminance. The PR structure obtained in the stage of lithography has asymmetric elliptical column shape and it is processed into a micro-optical pattern. Optical design with this kind of micro-optical pattern, mold fabrication by electroplating and LGP molding with injection molding are under way.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.184-190
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• 2003

$Sr_{0.9}Bi_{2.1}Ta_2O_9$thin films were deposited on $IrO_2$ electrode by spin coating method using photosensitive sol-gel solution. To ensure the UV-exposure effect on SBT thin films, UV irradiated films and non-UV irradiated films were analyzed by XRD, SEM. As a result, UV-irradiation on SBT thin films promoted grain growth of SBT compared with no UV irradiation. In case of the UV irradiated films annealed at$740{\circ}C$for 1 h in an oxygen ambient, the 2Pr value and Pr/Ps at${pm}5$V were$11.48{mu}C/cm^2$and 0.53, respectively. 2Pr values of the UV irradiated SBT thin films at$660-740{circ}C were approximately 12% higher than those of non-UV irradiated thin films.

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1093-1101
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• 2006

In the present study we studied the growth, photosynthetic traits and protective mechanisms against oxidative stress in the primary loaves of cucumber (Cucumis sativus L.) seedlings with or without UV-B treatment. Cucumber seedings were irradiated with UV-B for 10 days in environment-controlled growth chambers. The primary leaves irradiated with UV-B showed reduction in leaf length and decreased biomass production. The reduced biomass production seemed to be due to a negative effect of UV-B radiation on the photosynthetic process. Changes in chemical properties of leaf, such as chi a/b ratio affected photosynthesis. UV-B significantly affected chl b content compared with chi a in the light harvesting complex resulting reduced photosynthetic activity Fv/Fm decreased with an UV-B stress, suggesting that the photosynthetic apparatus, and particularly, PS II was damaged under UV-B stress. Malondialdehyde(MDA) concentration which represents the state of membrane lipid peroxidation Increased significantly under UV-B stress confirming an oxidative stress. UV-B exposure with SA solution(0.1-1.0 mM) can partially ameliorated some of the detrimental effects of UV-B stress. Leaf injuries including loss of chlorophyll and decreased ratio of Fv/Fm were reduced with combined application of UV-B and SA. ABA and JA showed similar mode of action in physiological effects on photosynthetic activities though the levels were lower than those from SA treated plants. Chloroplast ultrastructure was also affected by UV-B exposure. The thickness of leaf tissue components decreased and the number of grana and thylakoids was reduced in chloroplast applied UV-B or SA alone. At combined stress granal and stromal thylakoids were less affected. The leaves under combined stress acquired a significant tolerance to oxidative stress. From these results, it can be suggested that SA may have involved a protective role against UV-B induced oxidative damage.