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A CeO2-modified Ni catalyst has been studied as a substitute for Ni bulk catalyst in a CO removal reaction using various characterization methods. CO removal was enhanced slightly and presented at lower reaction temperatures following promotion of CeO2 on Ni. The enhanced ability to reduce CO was mainly a result of methanation rather than WGS during a CO removal reaction. Based on X-ray diffraction and temperature-programmed reduction, CeO2appeared to change the Ni surface properties. Because the bond strength between C and O atoms in CO was weakened by the surface oxygen of CeO2 on Ni, the CeO2-promoted Ni catalyst showed higher CO conversion and lower selectivity to WGS than Ni bulk catalyst.
The essential oil extracted from Asiasari radix was studied for anti-inflammatory activity against the-exudative and proliferative phase of inflammation by formalin filterpaper pellet-induced in Albino rats of either sex weighing between 180 and 250g. Indomethacin and Triamcinolone were used as standard drugs for comparison. The essential oil 0.5ml per 100g body weight daily in concentration of 0.1 and 0.2 % were given interaperitoneally in rats for six days. The granular tissue was weighed on the sixthday and histopathological changes were investigated on the third and sixth day. The results obtained were summarized as follows : 1. After six days of experiment, the weight of granular tissue of control group was 68.25mg, those of 0.1 and 0.2% essential oil were 30.16 and 29. 14mg respectively. The weights of experimental groups showed highly significant decrease, but there was no difference between two experimental groups. 2. Exudate and granular tissue formation around the filterpaper pellets of experimental groups were decreased on the third day, and on the sixth day they were decreased remarkably compared with exudate and granular tissue formation of control group. 3. Leucocytes infiltration-mostly heterophil leucocytes and a few macrophages and Iymphocytes-of control group was notable, and there was similar changes in experimental group on the third day, but on the sixth day changes of experimental group disappeared. 4. The weights of granular tissue of either standard groups were decreased more than that of experimental group. and even exudation, leucocytes infiltration and collagenous fiber of the former were dereased more than that of the latter.
Conductive hearing loss due to ossicular dislocation and facial paralysis may happen after temporal bone fracture. Incus dislocation is the most common problem among osscicular dislocations after temporal bone fracture. We experienced a case of incus dislocation into the mastoid cavity and facial paralysis after temporal bone fracture, which has not been reported. For the first time, we report a rare case with review of literature. Conductive hearing loss due to ossicular dislocation and facial paralysis may happen after temporal bone fracture. Incus dislocation is the most common problem among osscicular dislocations after temporal bone fracture. We experienced a case of incus dislocation into the mastoid cavity and facial paralysis after temporal bone fracture, which has not been reported. For the first time, we report a rare case with review of literature.
In order to investigate the effects on adrenal bodies of rabbits in short term administration of sulfadimethoxine(SDM) as medical dose, a total of 90 virgin albino rabbits were selected at random and alloted to two groups. Rabbits in one group served as controls and the others were administered SDM of 50 mg/kg/day for 5 weeks, and then reared without medication for 4 weeks. Histological changes of adrenal bodies were observed every week for 9 weeks, and the results obtained were summarized as follows: 1. The adrenal weights of experments were increased during administration of SDM, but they were decreased little after last administration. 2. The widths of adrenal cortex of experiments were increased during administration of SDM, but they were decreased after last administration. The widths of adrenal medulla of experiments were increased slightly during administration of SDM and even after last administration. 3. The epithelia of adrenal cortex and medulla of experiments showed the appearance of increased functions histologically during administration of SDM, but after last administration they showed recovering appearance.
에틸벤젠으로부터 크실렌으로의 이성질화 반응을 여러가지 이온교환된 Y-제올라이트 촉매상에서 기상반응으로 연구하였다. 사용한 모든 촉매는 Pt와 Bf₃를 Y-제올라이트에 담지하였고, 제올라이트 내에 존재하는 Na^+ 이온을 Fe^(+++), Cr^(+++), Ni^(++) 및 Ag^+ 등의 전이금속으로 치환하였다. 각 촉매에 대한 반응의 활성과 이성질화 반응에 대한 선택성을 고찰하였는 바, 반응온도, 반응압력, 수소/에틸벤젠의 몰비 및 액체공간속도(LWHSV)는 각각 420℃, 18기압, 5.9 및 1.62gr-feed/hr·gr-cat이었다. 주 생성물은 크실렌, 벤젠 및 톨루엔이었으며 기체크로마토그라피에 의하여 분석하였다. HX-제올라이트는 높은 선택성을, HY-제올라이트는 높은 활성을 나타낸 반면 H-모더나이트는 활성과 선택성이 모두 낮은 경향을 보여주었다. HCrY-제올라이트 및 HFeY-제올라이트는 정전기적 포텐샬에 기인되는 높은 크실렌으로의 선택성을 보여준 반면, HAgY-제올라이트 및 HCoY-제올라이트는 선택성이 낮았다. 교환된 이온의 양이 많을수록 촉매의 수명은 연장되었으며, 가장 우수한 HCrY-제올라이트 촉매는 약 21%의 이성질화 수율을 보였다. Vapor phase isomerization of ethylbenzene to xylene has been studied on various ion-exchanged Y-zeolites. For all catalysts, Pt and BF₃ were impregnated as main components on Y-zeolites and some transition metal ions were exchanged instead of Na^+ within zeolite. Fe^(+++), Cr^(+++), Ni^(++), Co^(++), and Ag^+ were used as transition metal ions. Both selectivity and activity of each catalyst have been investigated. The reaction temperature, reaction pressure, H₂/Ethylbenzene mole ratio, and LWHSV used in the study wexe 420℃, 18atm, 5.9, 1.62gr-feed/hr·gr-cat, respectively. The products were analyzed by gas chromatography, and the main products were xylene, benzene, and toluene. It has been found that HX-zeolite has high selectivity and HY-zeolite has high activity, whereas H-mordenite shows both low activity and selectivity. It is also observed that zeolite of HCrY and HFeY show a trend to enhance both activity and selectivity to xylene due to electrostatic potential, whereas zeolities of HAgY and HCoY have low activity and low selectivity to xylene. As the extent of ion exchange increases, it is found that deactivation of catalyst diminishes. The yield of 21% for isomerization was obtained using HCrY zeolite.
The formation of quasicrsatals in rapidly solidified Al-Li alloys have been investigated by detailed transmission electron microscopy, including a combination of bright and dark field imaging, selected area diffraction pattern analysis and energy dispersive X-ray microanalysis. Al-Cu-Li, Al-Cu-Li-Mg and 2024-2Li alloys rapidly solidified by melt spinning consist of various types of solidification microstructure, ranging form a fine columnar grain structure near the chilled ,surface to a coarse cellular structure near the unchilled surface, depending upon the wheel rotation speed during melt spinning and the local cooling rate through the thickness of the ribbon. Fine scale δ' precipitates during melt spinning in Al-Cu-Li, Al-Cu-Li-Mg and 2024-2Li alloys. The intercellular particles in as-melt spun Al-Cu-Li alloys are the T_8, Θ or T_2 icosahedral phases, depending upon the alloy composition, but in as-melt spun Al-Cu-Li-Mg and 2024-2Li alloys are always the icosahedral phase. Addition of Mg is effective in stabilizing the icosahedral phase in Al- Cu-Li alloys. The icosahedral phase forms as a second solidification product and is located at primary α-Al cell or dendrite boundaries, with strong dependence of icosahedral particle size upon the melt spinning wheel speed and local cooling rate. The composition of the icosahedral phase in rapidly solidified Al-Li alloys is not stoichiometric. Thus, the composition of the icosahedral phase in as-rapidly solidified Al-Cu-Li-Mg and 2024-2Li alloys can be expressed as (Al, Si)_6 (Cu, Fe, Mn)(Li, Mg)₃, assuming Si, Mg and (Mn, Fe) replacing Al, Li and Cu respectively in the Al_6CuLi₃ icosahedral structure.
압연된 스텐레스강봉(SUS 21)과 탄소강봉을 압입공차가 되도록 기계가공하여 프레스로 눌러끼워서 만든 피복 빌레트를 1050℃로 가열하여 630톤 프레스로 관재 및 봉재로 압출하였다. 압출 결과 압출율이 2.7이하인 경우에는 두금속의 결합이 전혀 일어나지 않았는데 반하여, 4.5이상인 경우에는 두금속의 고상결합이 양호하여 전단결합력이 28㎏/㎟ 정도였었다. 더욱이 고상결합된 시편을 1000℃에서 30분간 확산아닐링 시켰을때 전단 결합력이 34㎏/㎟으로 증가되었다. 압출율이 큰 경우에 나타났던 band structure는 압출율이 4.5이하인 본 실험에서는 나타나지 않았다.
K ion-added MgO catalysts were prepared by using KOH, KNO₃ or KCl as the precursor of K ion and applied to the coupling reaction of methanol and acetonitrile to form acrylonitrile. The reaction proceeds via acetonitrile carbanion intermediate which is formed on surface base site. The catalytic activity calculated by acetonitrile conversion was in the order KOH-added MgO > KNO₃-added MgO > KCl-added MgO which was in agreement with the trend of basic strength of the catalysts measured by CO₂-TPD. However, the selectivity to acrylonitrile was in the opposite order and the main by-product was propionitirle, the hydrogenated form of acrylonitrile. This suggests that hydrogenation also occurred an base site in this reaction. When CO₂ was introduced in the reaction system, acetonitrile conversion was increased suggesting that CO₂ played a role of mild oxidant in this reaction. Acetonitrile conversion and acrylonitrile selectivity over KNO₃-added MgO were 22.3% and 79.0%, respectively.