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        검색결과 14

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, two alignment methods were used to create a Fringe-Field Switching (FFS) mode liquid crystal device using an organic thin film (polyimide: PI) as an alignment layer. In addition, the electro-optical (EO) characteristics of the liquid crystal device manufactured in this way were investigated to evaluate the feasibility of mass production application of the technology. In general, the photo-alignment method using unpolarized ultraviolet rays can obtain a relatively low pretilt angle, so a liquid crystal device in FFS mode, which is a driving mode of the liquid crystal device that reflects the characteristics of liquid crystal alignment, was manufactured, and the liquid crystal has a high reactivity with the alignment film. Considering this, nematic liquid crystal (NLC) was used. In addition, in order to improve the misalignment, it was observed whether more stable orientation occurred by irradiating ultraviolet rays for an additional 1 to 3 hours in the aligned state. As a result of the experiment, it was found that NLC alignment occurs through a photodecomposition reaction caused by unpolarized UV irradiation oblique to the PI surface. In addition to the existing orientation method, UV irradiation was used to achieve a more stable orientation state and stable V-T curve and response characteristics. With liquid crystal alignment completed, more stable orientation characteristics and EO characteristics at the mass production level were obtained through additional UV irradiation for 3 hours. This method can further stabilize the orientation stability caused by existing UV irradiation through an additional process.
        4,000원
        2.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, as the demand for a non-contact liquid crystal alignment method capable of improving viewing angle characteristics has spread throughout the industry, various non-contact liquid crystal alignment methods, including conventional UV light alignment, are being actively studied. In the case of UV light alignment, it is currently applied to mass production in many fields and shows relatively excellent initial characteristics, but there is a problem of display quality deterioration over time. In this study, among these non-contact liquid crystal alignment methods, the liquid crystal is oriented by quantitatively irradiating an ion beam onto the SiOF inorganic film, which has excellent initial characteristics and does not cause deterioration in quality over time., the electro-optical properties were evaluated by manufacturing a commercial-level IPS (In-Plane Switching) liquid crystal cell. In particular, in the case of such inorganic film orientation, it is common to have many problems with orientation stability, but the evaluation cell manufactured by the method proposed in this study is capable of maintaining a uniform orientation without losing orientation even after heat treatment at a high temperature of 200°C. could be observed.
        4,000원
        3.
        2020.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        AZO thin films are grown on a p-Si(111) substrate by RF magnetron sputtering. The characteristics of various thicknesses and heat treatment conditions are investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Hall effect and room-temperature photoluminescence (PL) measurements. The substrate temperature and the RF power during growth are kept constant at 400 ℃ and 200 W, respectively. AZO films are grown with a preferred orientation along the c-axis. As the thickness and the heat treatment temperature increases, the length of the c-axis decreases as Al3+ ions of relatively small ion radius are substituted for Zn2+ ions. At room temperature, the PL spectrum is separated into an NBE emission peak around 3.2 eV and a violet regions peak around 2.95 eV with increasing thickness, and the PL emission peak of 300 nm is red-shifted with increasing annealing temperature. In the XPS measurement, the peak intensity of Al2p and Oll increases with increasing annealing temperature. The AZO thin film of 100 nm thickness shows values of 6.5 × 1019 cm−3 of carrier concentration, 8.4 cm−2/V·s of mobility and 1.2 × 10−2 Ω·cm electrical resistivity. As the thickness of the thin film increases, the carrier concentration and the mobility increase, resulting in the decrease of resistivity. With the carrier concentration, mobility decreases when the heat treatment temperature increases more than 500 ℃.
        4,000원
        4.
        2012.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO thin films were grown on a sapphire substrate by RF magnetron sputtering. The characteristics of the thin films were investigated by ellipsometry, X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL), and Hall effect. The substrate temperature and growth time were kept constant at 200˚C at 30 minutes, respectively. The RF power was varied within the range of 200 to 500 W. ZnO thin films on sapphire substrate were grown with a preferred C-axis orientation along the (0002) plan; X-ray diffraction peak shifted to low angles and PL emission peak was red-shifted with increasing RF power. In addition, the electrical characteristics of the carrier density and mobility decreased and the resistivity increased. In the electrical and optical properties of ZnO thin films under variation of RF power, the crystallinity improved and the roughness increased with increasing RF power due to decreased oxygen vacancies and the presence of excess zinc above the optimal range of RF power. Consequently, the crystallinity of the ZnO thin films grown on sapphire substrate was improved with RF sputtering power; however, excess Zn resulted because of the structural, electrical, and optical properties of the ZnO thin films. Thus, excess RF power will act as a factor that degrades the device characteristics.
        4,000원
        5.
        2011.09 구독 인증기관 무료, 개인회원 유료
        WCl6-EtAlCl2 촉매계를 이용하여 비교적 큰 분자량을 갖는 폴리(페닐아세틸렌)을 합성하였다. 중합반응이 잘 진행되었으며 중합수율은 81%였다. 합성한 폴리(페닐아세틸렌) 분자구조를 NMR(1H-,13C-), IR, UV-visible, 원소분석 등으로 분석한 결과 페닐 치환기를 갖는 공액구조 고분자가 합성되었음을 확인할 수 있었다. 아울러 332 nm의 빛으로 여기시킬 경우 PL 최대 peak는 424 nm에서 관찰되었는데, 이는 2.93 eV의 광 에너지에 해당한다. 이 고분자의 순환 전압전류 그림은 도핑과 탈도핑사이에서 비가역적인 전기화학적 거동을 보여주었다. 이 고분자의 전기화학적 과정이 매우 안정하였으며, 스캔속도에 따른 산화전류 밀도 실험으로부터 이 고분자의 산화-환언 과정은 확산-제어과정에 따르는 것으로 분석되었다.
        4,000원
        6.
        2010.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Mo thin films were used for the back electrode because of the low resistivity in the Mo/CuInGaSe2 contact inchalcopyrite solar cells. 1µm thick Mo thin films were deposited on soda lime glass by varying the Ar pressure with the dc-magnetron sputtering process. The effects of the Ar pressure on the morphology of the Mo back electrode were studied andthe relationships between the morphology and electro-optical properties, namely, the resistivity as well as the reflectance of theMo thin films, were investigated. The resitivity increased from 24µΩ·cm to 11833µΩ·cm; this was caused by the increasedsurface defect and low crystallinity as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The surface morphologies ofthe Mo thin films changed from somewhat coarse fibrous structures to irregular and fine celled strucutures with increased surfacecracks along the cell boundaries, as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The changes of reflectances in thevisible light range with Ar pressures were mainly attributed to the surface morphological changes of the Mo thin films. Thereflectance in the visible light range showed the highest value of 45% at 3×10−3Torr and decreased to 18.5% at 3×10−2Torr.
        4,000원
        7.
        2009.12 구독 인증기관 무료, 개인회원 유료
        Heck coupling 반응을 이용해서 poly{2-[2-(2,5-bis-dodecyloxy-4-propenyl-phenyl)-vinyl]- 7-methyl-fluoren-9-one(PFone), poly{2-[2-(2,5-bis-dodecyloxy-4-propenyl-phenyl)-vinyl]-7-methyl-fluoren-9-ylidene}-malonitrile(PF2CN)을 합성하였다. 합성한 중합체의 광학적, 전기화학적 특성을 흡수, 형광분광법 및 cyclic voltammetry(CV)를 통해 확인하였다. PFone과 PF2CN 필름의 흡수 극대치는 410 nm과 410.5 nm에서 나타났다. PFone 및 PF2CN의 최대 발광파장은 각각 633과 635nm로 나타났다. PFone과 PF2CN의 band gap은 각각 2.06eV 과 2.36eV이고 CV를 통해 측정한 LUMO 에너지 준위는 -3.36eV 와 -3.46eV로 나타났다.
        4,000원
        8.
        2009.12 구독 인증기관 무료, 개인회원 유료
        PAQ(poly-2-[2-(2,5-Bis-dodecyloxy-4-vinyl-phenyl)-vinyl]-anthraquinone)과 PAN4CN(poly- 2-{2-[2-(2,5-Bis-dodecyloxy-4-vinyl-phenyl)vinyl]-10-dicyanomethylene-10H-anthracen-9-ylidene}-malononitrile)을 Heck coupling reaction을 이용하여 합성하였다. 합성한 중합체의 전기적, 광학적 특성은 UV-visible spectra, photoluminescence (PL) spectra 및 cyclic voltammetry 측정을 통해 확인하였다. 흡수 스펙트라 측정 결과, thin film에서의 흡수극대치는 PAQ 와 PAN4CN은 334nm에서 나타났고, 용액에서는 PAQ 338nm, PAN4CN은 336nm 나타났다. 발광 극대치의 측정결과 PAQ는 thin film에서 420nm와 용액상에서는 416nm, PAN4CN은 thin film에서 395nm와 용액에서는 550nm로 각각 나타났다. PAQ과 PAN4CN의 band gap은 각각 2.16 eV, 2.04 eV이고 CV를 통해 LUMO 준위는 -3.64eV, -3.52eV로 나타났다.
        4,000원
        10.
        2001.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        교류구동형 플라즈마 표시소자의 보호막으로 사용되는 MgO의 특성향상을 위하여 기존의 MgO에 양이온이 등전적으로 치환될 수 있는 ZnO를 소량 첨가하여 고주파 마그네트론 스퍼터링 방법으로 Mg1-xZ nxO박막을 성장시키고 박막의 전기적, 광학적 특성을 조사하였다. ZnO농도가 0.5 at%, 1at%인 Mg1-xZ nxO 박막을 보호막으로 갖는 PDP 테스트 판넬을 제작하고 ZnO의 첨가가 소자의 방전전압과 메모리 이득에 미치는 영향을 살펴보았다. ZnO농도가 0at%, 0.5 at%, 1at%인 Mg1-xZ nxO 박막의 광투과율은 ZnO 첨가에 따라 변화를 보이지 않으나 유전상수는 다소 증가하는 경향을 보였다. ZnO의 농도가 0.5 at%인 Mg1-xZ nxO 박막을 보호막으로 갖는 PDP 소자의 방전개시전압과 방전유지 전압이 MgO 박막을 보호막으로 갖는 소자에 비해 20V까지 낮아졌고, 결과적으로 메모리계수는 다소 증가하였다. ZnO농도가 0.5 at%, 1at%인 Mg1-xZ nxO 박막을 보호막으로 갖는 소자에서 ZHO의 첨가에 비례하여 방전세기 (플라즈마 밀도)가 증가하였다.도)가 증가하였다.도)가 증가하였다.
        4,000원
        12.
        1995.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The phase separated structure and the electro-optical properties of the (polymer/liquid) crystal : LC) composite film strongly depended on the weight fraction of LC in it. The continuous LC phase was formed in a three-dimensional polymer network when the LC weight fraction was above 40wt%. The aggregation structure of the composite film could be controlled by controlling the solvent evaporation velocity during the film preparation process. The smaller LC domains or channels were formed in the case of the faster solvent evaporation velocity. The composite film exhibited reversible light scattering-light transmission switching upon electric field -OFF and -ON states, respectiverly. The light scattering properties of the composite film strongly depended on the spatial distortion of the nematic directors as well as the mismatch in refractive indices between matrix polymer and LC.
        4,200원
        13.
        1993.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        PVC/액정 복합막의 응집상태 및 전기광학 특성을 넓은 막조성(30-70wt% LC)에 걸쳐 조사하였다. 또한 optical contrast가 가장 좋은 40/60(PVC/LC)중량조성으로 된 복합막에 대해서는 온도 및 외부교류전계의 주파수 및 전압응답을 측정한 결과 문턱 주파수는 20Vp-p 이하(1 kHz, 25˚C), rise time및 decay time은 모두 10ms 이하(V100 p-p , 1 kHz, 25˚C)였다.
        4,000원
        14.
        1991.12 서비스 종료(열람 제한)
        This paper is compared with fourier series and least square polynomial fit and interpolation to mechanism stated number in electro-optical distance measuring instrument. Systematic instrumental errors occurring in electro-optical systems include uncertainties in the position of the electrical center of the transmitter, uncertainties in the effective center of the reflectors. frequency drift and instrument nonlinearity. Microwave systems are affected by uncertainties in the electrical centers of the master and remote units and by a phenomenon called group swing or reflection. As the result of this study, mechanism stated number will be used as verification of electro0optical measuring instrument to distance measurement.