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        검색결과 9,514

        6737.
        2002.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A mixture of methyl ester derivatives of fatty acids from the oils of pine nuts was well resolved to five fractions differing by degree of unsaturation by silver ion solid-phase extraction column chromatography (Ag+-SEC). Polyunsaturated fatty acid with non-methylene interrupted conjugated double bond (NMiDB) radical held more strongly to silver ions in the column than methylene interrupted conjugated double bond (MiDB) one when they had the same number of double bonds. Although both the picolinyl ester and DMOX derivative provided clear mass ion species powerful enough to elucidate the structure of the polyunsaturated fatty acid (PUFA) with NMiDB and/or methylene interrupted conjugated double bond (MiDB) radical in the oils, the picolinyl ester of PUFA with NMiDB radical did not provide a cluster of mass ions neighboring diagnostic mass ions induced by the double bond in the proximal to the carboxyl group. However, the DMOX derivative of PUFA with NMiDB group as well as MiDB showed abundant mass ion species differing by gaps of 12 amu, which made it possible with greater ease to locate the double bonds in the molecule. The oil contained C18:2Ω6 (46.2 %) and C18:1Ω9 (25.4 %) as main components, and considerable amounts of PUFAs with NMiDB radical such as δ5. 9. 12-C18:3 (16.0 %), δ5. 9-C18:2 (2.3 %) and δ5. 11. 14-C20:3 (0.8 %).
        6,000원
        6738.
        2002.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The color stability and purity from OLED is of current interest. Aggregation of dyes alters the device color after fabrication of the devices. Exciplex and electroplex formations have been proposed to explain the aggregate color change. We investigate the possibility of exciplex formation and propose the new electroplex state that can cause the bathochromic shift of the electroluminescence spectrum from the devices with TPD/PBD layers. The photoluminescence maximum of the device was 420nm, and the electroluminescence maximum of the device to became 480nm. The bathochromic shift cannot be attained with photoluminescence study with highly concentrated TPD/PBD mixture. This clearly indicates that the 480nm spectrum of the devices is not resulted from the exciplex formation with TPD and PBD. We observed the overshoot in EL spectrum from the OLEDs. The most intense overshoot was observed at 460nm, which may be due to the aggregates that are formed after the electric field has been removed from the devices.
        4,000원
        6739.
        2002.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        From the data of solar wind observation by ACE spacecraft orbiting the Earth-Sun Lagrangian point, we selected 48 forward interplanetary shocks(IPSs) occurred in 2000, maximum solar activity period. Examining the profiles of solar wind parameters, the IPSs are classified by their shock drivers. The significant shock drivers are the interplanetary coronal mass ejection(ICME) and the high speed stream(HSS). The IPSs driven by the ICMEs are classified into shocks driven by magnetic clouds and by ejectas based on the existence of magnetic flux rope structure and magnetic field strength. Some IPSs could be formed as the blast wave by the smaller energy and shorter duration of shock drivers such as type II radio burst. Out of selected 48 forward IPSs, 56.2% of the IPSs are driven by ICME, 16.7% by HSS, and 16.7% of the shocks are classified into blast-wave type shocks. However, the shock drivers of remaining 10% of the IPSs are unidentified. The classification of the IPSs by their driver is a first step toward investigating the critical magnitudes of the IPS drivers commencing the magnetic storms in each class.
        4,000원
        6740.
        2002.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbon fibers were prepared from the petroleum isotropic pitch and organometallic compounds. The metals were dispersed uniformly in the ACFs. The specific surface area and pore size distributions of metal containing ACFs were measured. The mesopores of ACFs were developed by Co, Ni, and Mn metals addition, and the catalytic reactivity of ACFs' SOx removal was increased by adding Ni and Pd metals. It was found that the mesopores did not work forthe improvement of catalytic reactivity of ACFs' SOx removal with the blank experiment using the metal removed ACFs.
        4,000원