• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.37-43
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• 2007

We developed the equipment to measure the MTF(modulation transfer function) of an optical system for automatically inspecting the surface condition of an LCD substrate. We have made an object generator with USAF(United States Air Force) targets of three bar patterns and an integrating sphere, and an image analyzer with a 2 dimensional CCD(charge coupled device) and a relay lens. The MTF of the lens under test was obtained by correcting the measured CTF(contrast transfer function) which is the ratio of the contrast in the image of the USAF target to the contrast in the object. We have measured an optical system of F/13.65 (2.6x), the MTF are 30.6 % tangential plane and 26.1 % sagittal plane at 62.5 1p/mm.

• Korean Journal of Optics and Photonics
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• v.28 no.1
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• pp.1-8
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• 2017

A method for inspecting defects in display substrates utilizing Fourier optics is proposed in this paper. A cost-effective inspection system can be realized with the proposed method, because it does not require a high-magnification microscope. Also, the proposed method can avoid tight tolerance for variations in displacement between substrate and camera, which is stems from shallow depth of field of the high-magnification microscope. In addition, possible damage caused by collisions between substrate and the inspection equipment can be avoided. The decision algorithm can be simpler than for a conventional inspection system, because spatial shift of periodic substrate patterns does not affect the intensity distribution of the diffracted light, by the Fourier transform property. The proposed method is explained with numerical studies, and experiments are carried out to check its feasibility for color-filter substrates of a liquid-crystal display.

• Korean Journal of Veterinary Service
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• v.37 no.2
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• pp.123-129
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• 2014

This research was performed in order to investigate the origin, standard compound, and structural and physical properties of honeybee venom which used as natural antibiotic ingredients to animal. We compared the nucleotide sequence of mitochondrial cytochrome c oxidase subunit 1 gene (COI) of honeybees were collected from Gangwon, Gyeonggi, Chungnam, Gyeongbuk, Gyeongnam province and Suwon. As major constituent of honeybee venom, melittin was assayed by liquid chromatography. X-ray, differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FT-IR) were utilized to examine the structural and physical properties of honeybee venom. Based on the 627bp sequence of COI, Apis mellifera ligustica was determinated honeybees collected from all six regions. Melittin content varied from 50.7 to 68.6 and averaged 59.8%. According to XRD analysis, honeybee venom showed regular crystal structure peaks at $2{\Theta}=8.5^{\circ}$ and $21.5^{\circ}$. DSC showed that the maximum degration temperature of powder was around $230^{\circ}C$. Through FT-IR analysis, we could identify cross-linking by the presence of peptide peak at 1,500~1,600 $cm^{-1}$. In conclusion, the origin of honeybee venom was Apis mellifera ligustica and effective ingredient standards was melittin content varied from 50.7 to 68.6 as natural antibiotic ingredients.

• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.403-409
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• 2016

In this study, a TiO₂ nanotube was grown on a titanium plate by using anodic oxidation method for the evaluation of TiO₂ nanotube morphology. The TiO₂ nanotube was grown in an electrolyte containing ethylene glycol, 0.2 wt% of NH₄F and 2 vol% of H₂O. Applied voltage varied from 30 to 70 V and the morphology of the TiO₂ nanotube was observed. After anodization, a TiO₂ nanotube plate was immersed in 35℃ ethanol for 24 hours. Anatase and rutile crystal forms of TiO₂ nanoutbe were observed after annealing. 4-chrolobenzoic acid, a probe compound for OH radicals, was dissolved in H₂O in order to measure the OH radical. Liquid chromatography was used to check the concentration of the 4-chrolobenzoic acid. The OH radical generation by TiO₂ nanotube plate was proportionate to the length of the TiO₂ nanotube. Furthermore, when the number of TiO₂ nanotube plate increased, the OH radical generation increased as well.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.90-94
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• 2016

In this work, [$Pb(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_x(Zr_{0.5}Ti_{0.5})_{0.97-x}O_3-BiFeO_3$] (x=0.02 to 0.12) composition ceramics were fabricated by the conventional soild state reaction method and their microstructure and piezoelectric properties were investigated according to PNN substitution. The addition of small amount of $BiFeO_3$, $Li_2CO_3$, and $CaCO_3$ were used in order to decrease the sintering temperature of the ceramics. The XRD (x-ray diffraction patterns) of all ceramics exhibited a perovskite structure. The sinterability of PMW-PNN-PZT-BF ceramics was remarkably improved using liquid phase sintering of $CaCO_3$, $Li_2CO_3$. However, it was identified from of the X-ray diffraction patterns that the secondary phase formed in grain boundaries decreased the piezoelectric properties. According to the substitution of PNN, the crystal structure of ceramics is transformed gradually from a tetragonal to rhombohedral phase. The x=0.10 mol PNN-substituted PMW-PNN-PZT-BF ceramics sintered at $920^{\circ}C$ showed the optimum values of piezoelectric constant($d_{33}$), piezoelectric figure of merit($d_{33{\cdot}}g_{33}$), planar piezoelectric coupling coefficient($k_p$) and density : $d_{33}=566$ [pC/N], $g_{33}=29.28[10^{-3}mV/N]$, $d_{33{\cdot}}g_{33}=16.57[pm^2/N]$, $k_p=0.61$, density=7.82 [$g/cm^3$], suitable for duplex ultrasonic sensor application.

• Elastomers and Composites
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• v.40 no.3
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• pp.212-221
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• 2005

Polyurethanes containing mesogen unit (MPU-6) were prepared from 4,4'-diphenylmethane diisocyanate (MDI) and 4,4'-bis(6-hydroxy hexoxy)biphenyl (BP-6) having flexible chain composed of 6 carbons. Intrinsic viscosities of MPU-6s were in the range of $0.23{\sim}0.56 dL/g$. The mesomorphic behaviors of MPU-6 were observed in X-ray and polarizing microscopy analysis. However, MPU-6s demonstrated a 'virtual liquid crystal' behavior, which did not exhibit mesophase on slow heating and slow cooling. MPU-6 having lower molecular weight exhibited higher crystallization rate and melting crystallization temperature due to increased mobility of polymer chains. The increased mobility of polymer chains facilitate the orientation of mesogen units that may act as a nucleating agent.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.6
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• pp.123-131
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• 2009

The emerging display technology has been replaced the previous position of the CRT with the LCD. The nature of hold type display such as LCD, however, causes many problems such as motion blur and motion judder. To resolve the problems, we used frame interpolation technique which improves the image quality by inserting new interpolated frames between existing frames. In this paper, we propose a novel frame interpolation technique that uses dominant MV and variance different value in each block. At first, the proposed algorithm performs unidirectional motion estimation using blocking matching algorithm. The new frame is generated by pixel average using compared block variance or by pixel motion compensation using dominant motion vector, whether the motion estimation find the target area or not. Several experiments with the proposed algorithm shows that the proposed algorithm has better image quality than the existing bidirectional frame interpolation algorithm at the rate of about 3dB PSNR and has low complexity comparing to the unidirectional frame interpolation technique.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.739-744
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• 2011

Activated carbon SCR(CSCR) catalyst that is used to remove $NO_x$ in exhaust gas including boron discharged from the production process of liquid crystal display(LCD) shows deactivation when boron is deposited to block the pores within the catalyst or to cover its active sites. The spent carbon catalyst is regenerated by washing with various surfactants, drying and calcination. For comparison of the physical and chemical properties before and after the regeneration with the variables, type of surfactants and calcination condition, element analysis by ICP, $N_{2}$ adsorption were conducted. $DeNO_{x}$ in SCR with $NH_3$ was carried out in a fixed bed reactor at $120^{\circ}C$. The activated carbon catalyst regenerated through washing with a non-ionic surfactant in $H_{2}O$ at $90^{\circ}C$ and calcination under $N_{2}$ gas at $550^{\circ}C$ shows similar level of surface area and $NO_x$ removal efficiency with those of fresh catalyst.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.4
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• pp.161-168
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• 2001

Organic thin film transitors(TFTs) are of interest for use in broad area electronic applications. For example, in active matrix liquid crystal displays(AMLCDs), organic TFTs would allow the use of inexpensive, light-weight, flexible, and mechanically rugged plastic substrates as an alternative to the glass substrates needed for commonly used hydrogenated amorphous silicon(a-Si:H). Recently pentacene TFTs with carrier field effect, mobility as large as 2 $cm^2V^{-1}s^{-1}$ have been reported for TFTs fabricated on silicon substrates, and it is higher than that of a-Si:H. But these TFTs are fabricated on silicon wafer and $SiO_2$ was used as a gate insulator. $SiO_2$ deposition process requires a high insulator which is polyimide and photo acryl. We investigated trasfer and output characteristics of the thin film transistors having active layer of pentacene. We calculated field effect mobility and on/off ratio from transfer characteristics of pentacene thin film transistor, and measured IR absorption spectrum of polymide used as the gate dielectric layer. It was found that using the photo acryl as a gate insulator, threshold voltage decreased from -12.5 V to -7 V, field effect mobility increased from 0.012 $cm^2V^{-1}s^{-1}$ to 0.039 $cm^2V^{-1}s^{-1}$ , and on/off current ratio increased from $10^5\;to\;10^6$. It seems that TFTs using photo acryl gate insulator is apt to form channel than TFTs using polyimide gate insulator.

• Convergence Security Journal
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• v.11 no.3
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• pp.55-66
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• 2011

This research focus on the value of smart phones for university students in Korea, considering on the correlations between the main causes influencing intrinsic value(price attributes, function attributes), network value(learning effects attributes, externalities attributes) user satisfaction, and intentions of repurchase of the smart phones market in Korea. Through the statistical analyses on the 8 hypotheses from a research model, we found that intrinsic value and network value gave an attentive influence on user satisfaction and repurchase intention. Call charge and Liquid crystal display and Design of smart phone have an influenced user satisfaction and repurchase intention.