• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.178-181
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• 2001

The electro-optical (EO) characteristics 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 of 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.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.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.73-75
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• 2011

In the collisionally-activated dissociation of the proton-bound cluster ions of DNA base guanine (G) and cytosine (C), $G{\bullet}{\bullet}H^+{\bullet}{\bullet}C$, the abundance of [$CH^+$] ions was found to be higher than that of [$GH^+$] despite the fact that G has a higher proton affinity than C. This unexpected observation seems to demonstrate another example that the simple kinetic method scheme does not work. We suggest that a kinetic factor or detailed dynamics governing the proton transfer and dissociation should be carefully considered in the applications of the kinetic method to the proton affinity measurements.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.273-273
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• 2006

Over the past years, a large number of acrylate polymers have been developed and the overcoat thin layer containing acrylate polymers have been used for TFT-LCD color filter. As forming thin layer using acrylate polymers, the existing acrylate polymers have some problems such as low hardness by low Tg temperature, coating uniformity and solubility in organic solvent. To solve these problems, we synthesized new polymer(Scheme.), containing olefin monomer, which has high Tg temperature, good coating uniformity and good solubility in organic solvent. The overcoat thin layer containing new polymer resulted in good coating uniformity, stain, spot, scratch, heat resistance, DOP(Degree Of Planarization) on RGB glass, transparency, hardness, adhesion, anti-chemicals(anti-acid, anti-base, anti-organic solvent), insulation and anti-humidity. Scheme. The structure of new polymer X = Olefin monomer contains ketone, ester, hydroxy, ether, halogen, nitrile, alkoxy, phenyl functional group $R_1$ and $R_2$= H or $CH_3$. Ratio=0<[1/(1+m+n)]<0.7,0.1[$\leq$[n/(1+m+n)]<0.5.

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.251-254
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• 2008

Blue-white reflective cholesteric liquid crystal display was prepared by a unique method of single liquid crystal layer, the combination of yellow color liquid crystal and blue color backplane. The dopant and host combination of chlolesteric liquid crystal affects the color spectrum. The CIE chromaticity coordinates of blue and white are (0.10, 0.16) and (0.29, 0.30), respectively. The relatively low driving voltages of 32 V for blue-white display are obtained.

• Transactions on Electrical and Electronic Materials
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• v.10 no.1
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• pp.20-23
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• 2009

Black-white reflective cholesteric liquid crystal display was prepared with two color liquid crystal layers, the combination of yellow color liquid crystal and blue color liquid crystal. The rubbing of cholesteric liquid crystal panel affects the brightness and color spectrum due to increase the planar domain texture. The CIE chromaticity coordinate of white is (0.31, 0.31).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.381-388
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• 2015

In this paper, a wireless video streaming system is designed and implemented for TV white space applications. It consists of a RF transceiver module, a digital modem, a camera, and a LCD screen. A VGA resolution video is captured by a camera, modulated by modem, and transmitted by RF transceiver module, and finally displayed at a destination 2.6-inch LCD screen. The RF transceiver is based on direct-conversion architecture. Image leakage is improved by low pass filtering LO, which successfully covers the TVWS. Also, DC offset problem is solved by current steering techniques which control common mode level at DAC output node. The output power of the transmitter and the minimum sensitivity of the receiver is +10 dBm and -82 dBm, respectively. The channel bandwidth is tunable among 6, 7 and 8 MHz according to regulations and standards. Digital modem is realized in Kintex-7 FPGA. Data rate is 9 Mbps based on QPSK and 512ch OFDM. A VGA video is successfully streamed through the air by using the developed TV white-space RF communication module.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.629-637
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• 2023

This study aimed to evaluate the effect of post-curing equipment and time on the flexural strength of 3D printing resins produced by a liquid crystal display(LCD) printer. The three 3D printing resins(DENTCA Denture Teeth, DT; C&B 5.0 hybrid, CH; C&B Permanent A2, CP) were divided into four groups according to post-curing time(10 min and 30 min) and equipment with or without vacuum treatment. For the three-point flexural strength test and biaxial strength test were prepared by method according to ISO 10477, ISO 6872, respectively. Flexural strength was measured with universal testing machine. Comparison between post-curing time of each post-curing equipment was analyzed by independent sample t-test and Mann-Whitney U test(α=.05), and comparison between groups according to each 3D printing resin was performed by Kruskal-Wallis test and post-hoc by Bonferroni-Dunn test(α=.05). The flexural strength of the resin post-curing under vacuum was higher than that of the resin post-curing in air. In the comparison according to the post-curing time, in the case of the post-curing equipment without vacuum, the 30 minute curing time showed significantly higher flexural strength than the 10 minute curing time, except for the biaxial flexural strength of CH(P<.05). In the post-curing equipment with vacuum, the three-point flexural strength of all 3D printing resins(DT, CH, and CP) showed a higher value at 30 minute curing time than at 10 minute curing time.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1225-1228
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• 2004

We have studied the Polymer Stabilized Continuous Director Rotation (PSCDR) mode to solve the thermal shock problem which is core and main problem in CDR mode. The cell filled 95wt. % R2301 FLC and 5wt. % UCL-001 polymer is applied a low DC voltage only near the phase transition temperature from cholesteric to chiral smectic C phase transition to get defect-free alignment. In the previous work, we also confirmed layer deformation induced by an applied DC field only near the phase transition temperature from Ch to $SmC^{\ast}$. Results of layer structure, and characteristics of electro-optical properties between CDR and PSCDR mode will be discussed in this paper. We are also in progress to finalize the layer structures compared between CDR and PSCDR mode by x-ray measurements.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.71-75
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• 1998

Liquid crystalline compounds with amine terminal group and related linear and cross-linked liquid crystal polymers with epoxy resin structure were synthesized and characterized to develope matrix materials for polymer dispersed liquid display applications. Both linear and crosslinked side chain type liquid crystal polymers made with aromatic amine mesogens and ethylene glycol diglycidyl ether exhibited nematic texture as shown by polarized optical microscope(POM) and their transition temperatures were determined both by DSC and POM. Liquid crystal polymer samples also showed even-odd effect as the spacer length of aromatic amine mesogens were varied, however, the effect was samller than that of low molecular weight mesogens. Changes of nematic-to-isotropic transition($T_{NI}$) of crosslinked type polymer liquid crystals were also disscussed in relation to the concentration change of crosslinking agent 1,10-diaminodecane.