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LC Orientation Characteristics Treated on Organic Hybrid Overcoat Layer with Ion Beam Irradiation
이상극,김병용,김영환,이강민,오병윤,한정민,서대식 한국전기전자재료학회 2008 Transactions on Electrical and Electronic Material Vol.9 No.5
We have studied the liquid crystal (LC) orientation behavior on the organic hybrid overcoat layer with ion beam irradiation. Excellent LC alignments of the nematic liquid crystal (NLC) on the ion beam irradiated organic hybrid overcoat layers were observed in various intensities above 600 eV. Pretilt angles of the NLC on the organic hybrid overcoat layers for all ion beam energy intensities were observed from 0.2 to 0.5 degrees. Also, we used the atomic force microscopy (AFM) images for measuring the roughness of the organic hybrid overcoat layers with ion beam irradiation before and after. The surface of organic hybrid overcoat layers was leveled off by the ion beam irradiation. Finally, a good LC alignment thermal stability on the organic hybrid overcoat layer with ion beam irradiation can be achieved.
Annealing Behavior of Pretilt Angles on Polyimide Surface with Rubbing and Ion Beam Irradiation
이상극,임지훈,오병윤,김영환,한정민,서대식 한국전기전자재료학회 2008 Transactions on Electrical and Electronic Material Vol.9 No.6
We have studied the liquid crystal (LC) alignment, the pretilt angle generation, and the annealing behavior for a nematic liquid crystal (NLC) on the homogeneous polyimide (PI) surfaces by using the rubbing method and the ion beam (IB) method. An excellent LC alignment of the NLC on the PI surface with rubbing and IB irradiation were observed. The pretilt angle of NLC on the homogeneous PI surface for the rubbing method is decreased from 4.5 ° to 3.5 ° as rubbing time is increased, that of the for the IB irradiation method is decreased from 0.5 ° to 0.1 ° as the time of IB irradiation is increased. After the annealing, the pretilt angles of the rubbed PI surfaces increased up to 4 °, these of the IB irradiated PI surfaces little increased. It is considered the side chain of the rubbed PI show the its abilities of the original capacities, while the side chain of the IB irradiated PI cannot show the its abilities of the original capacities due to the IB has already destroyed the side chain of the PI.
노간주나무 (Juniperus rigida Siebold et Zucearini) 잎의 추출성분 및 항산화 활성
이상극,김진규,함연호,배영수 한국목재공학회 2004 목재공학 Vol.32 No.1
노간주나무 잎을 채취하여 건조시킨 후 분말로 제조하여 1.5 ㎏을 아세톤-물(7:3, v/v)로 추출하고 헥산, 메틸렌클로라이드, 에틸아세테이트 및 수용성으로 분획하여 동결 건조시켰다. 그 중에서 에틸아세데이트용성과 수용성 분획을 Sephadex LH-20으로 충진한 칼럼에서 메탄올과 에탄올-헥산 혼합액을 용리용매로 사용하여 칼럼크로마토그래피를 실시하였다. 단리된 화합물들은 TLC로 확인한 후 NMR스펙트럼을 사용하여 정확한 구조를 규명하였고 FAB 및 EI-MS로써 분자량을 측정하였다. 주로 많은 양의 (+)-catechin, quercetin-3-O-α-L-rhamnopyranoside와 isoconiferin이 분리되었으며, 소량의 umbelliferone과 quercetin-3-O-β-D-rutinoside도 분리되었다. 각 분획물들과 단리된 화합물들은 DPPH 라디칼 소거법을 이용하여 항산화실험을 실시하였으며, 분획물중에는 에틸아세테이트용성이 그리고 화합물중에는 (+)-catechin과 quercetin-3-O-α-L-rhamnopyranoside이 우수한 항산화 효능이 있는 것으로 나타났다. The dried neeldes(l.5 ㎏) of Juniperus rigida were ground, extracted with acetone-H₂O(73, v/v), concentrated, and fractionated with a series of hexane, CH₂Cl₂ EtOAc and water on a separatory funnel. Each fraction was freeze dried to give dark-brown powder and EtOAc and water soluble fractions were chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluent. Spectrometric analysis such as NMR and FAB or EI-MS including TLC were performed to characterize the structures of the isolated compounds. The needles of Juniperus rigida contained a large amount of (+)-catechin, quercetin-3-O-α-L-rhamnopyranoside and isoconiferin, in addition to a small amount of umbelliferone and quercetin-3-O-β-D-rutinoside. The antioxidative activities of each fraction and isolated compounds were tested by DPPH radical scavenging method, and EtOAc soluble fraction, (+)catechin and quercetin-3-O-α-L-rhamnopyranoside were effective.
이상극,황정연,서대식,이준웅 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.4
In this study, we investigated about electrooptics characteristic of three kinds of TN cell on the polyimide surface. Monodomain alignments of thermal stressed TN cell over temperature of liquid crystal isotropic phase were almost the same as that of no thermal stressed TN cells. However, the thermal stressed TN cells have many defects. Also, threshold voltage and response time of thermal stressed TN cells show the same performances as no thermal stressed TN cells. There were little changes of value in these TN cells. However, transmittances of TN cells on the polyimide surface decrease with increasing thermal stress time. Finally, the residual DC voltage of the thermal stressed TN cell on the polyimide surface shows decrease of characteristics as increasing thermal stress time. Therefore, the thermal stability of TN cell was decreased by high thermal stress for the long times.