• Title/Summary/Keyword: Ethylene oxide

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The Effect of Adsorbed Oxygen Species on the Partial Oxidation of Ethylene over Ag/α-Al2O3 (Ag/α-Al2O3 촉매상에서의 에틸렌 부분산화반응에 미치는 흡착산소종의 영향)

  • Baik, Choong-Hoon;Lee, Sang-Gi;Yeo, Jong-Kee;Lee, Ho-In
    • Applied Chemistry for Engineering
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    • v.5 no.4
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    • pp.609-615
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    • 1994
  • Partial oxidation of ethylene over 10wt% $Ag/{\alpha}-Al_2O_3$ catalyst was studied with a pulse reactor which was connected directly to a G. C. When ethylene was injected after oxygen injection at the temperature where molecular adsorption of oxygen is difficult ethylene oxide was evolved. From the results, it is suggested that adsorbed atomic oxygen is related with the evolution of ethylene oxide. The selectivity to ethylene oxide decreased with the decrease of the amounts of adsorbed oxygen and bulk oxygen. Ethylene oxide was either decomposed to ethylene and adsorbed oxygen or isomerized to acetaldehyde. However, the isomerization of ethylene oxide to acetaldehyde was strongly suppressed by the preadsorbed oxygen.

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Release of Cytarabine from $Poly({\varepsilon}-carbobenzoxy\;L-lysine)$/Poly(ethylene oxide)/Poly({\varepsilon}-carbobenzoxy\;L-lysine)$ Block Copolymer Microspheres ($Poly({\varepsilon}-carbobenzoxy\;L-lysine)$/Poly(ethylene oxide)/$Poly({\varepsilon}-carbobenzoxy\;L-lysine)$ 블록 공중합체 미립자에서 Cytarabine의 방출특성)

  • Cho, Chong-Su;Kwon, Joong-Kuen;Jo, Byung-Wook;Lee, Kang-Choon;Sung, Yong-Kiel
    • Journal of Pharmaceutical Investigation
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    • v.22 no.4
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    • pp.323-326
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    • 1992
  • $Poly({\varepsilon}-carbobenzoxy\;L-lysine)/poly(ethylene oxide)/poly({\varepsilon}-carbobenzoxy\;L-lysine)$ (LEL) block copolymers containing $poly({\varepsilon}-carbobenzoxy\;L-lysine)$ (PCLL) as the A component and poly(ethylene oxide) (PEO) as the B component were investigated as drug delivery matrix. PCLL homopolymer and LEL block copolymer microspheres containing anticancer drug, cytarabine, were prepared by a solvent evaporation process and the release patterns of cytarabine from the microspheres were investigated in vitro. The size of PCLL homopolymer and LEL block copolymer microspheres was ranged from $0.2\;{\mu}m$ to $1\;{\mu}m$ in diameter and the shape of the microspheres was almost round. The release pattern of cytarabine from the block copolymer microspheres was dependent on the mole % of PEO of the block copolymers.

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Effects of Ethylene Oxide and Gamma Energy on the Flavor-Related Components of Mushrooms (Lentinus edodes) (표고버섯의 향미관련 성분에 대한 에틸렌옥시드와 감마에너지의 영향)

  • 권중호;변명우;정신교;조한옥
    • Journal of Food Hygiene and Safety
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    • v.7 no.1
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    • pp.7-14
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    • 1992
  • Flavor-related components were analyzed for dried oak mushrooms (Lentinus edodes) when subjected to ethylene oxide and gamma energy. Volatile flavor components identified by GC and GC-MS were composed primarily of l-oden-3-ol (72.8%), 3-octanone (11.5%) and dimethyl disulfide (6.7%). Most of volatile components were shown labile to the standard cycle of ethylene oxide and 5 kGy-gamma energy, while insignificant changes were observed in the contents of free sugars (mannitol, arabitol, trehalose) and free amino acids. Instrumental analysis have shown, however, that the deterimental effects on flavor-related components were more apparent in EO-fumigated groups than in gamma-irradiated ones, even though the organo-leptic test revealed no significant differences between treated samples and the corresponding control.

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The Characteristics of Nano-sized Cobalt Oxide Particles Prepared by Low Pressure Spray Pyrolysis (저압 분무열분해법에 의해 합성된 나노 크기의 코발트 산화물 입자의 특성)

  • Ju, Seo-Hee;Kim, Do-Youp;Kang, Yun-Chan
    • Korean Journal of Materials Research
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    • v.16 no.9
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    • pp.538-542
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    • 2006
  • Nano-sized cobalt oxide powders were prepared by low pressure spray pyrolysis process. The precursor powders obtained by low pressure spray pyrolysis process from the spray solution with ethylene glycol had several microns size and hollow structure. The precursor powders obtained from the spray solution with optimum concentration of ethylene glycol formed the nano-sized cobalt oxide powders with regular morphology after post-treatment without milling process. On the other hand, the cobalt oxide powders obtained from the spray solution without ethylene glycol had submicron size and spherical shape before and after posttreatment. The mean size of the cobalt oxide powders formed from the spray solution with concentration of ethylene glycol of 0.7M was 180 nm after post-treatment at temperature of $800^{\circ}C$. The mean size of the powders could be controlled from several tens nanometer to micron sizes by changing the post-treatment temperatures in the preparation of cobalt oxide powders by low pressure spray pyrolysis process.

Preparation and Characterization of Poly$({\gamma}-benzyl\;L-glutamate)$/Poly(ethylene oxide)-Lactoselactone Block Copolymers and Their Microspheres (Poly$({\gamma}-benzyl\;L-glutamate)$/Poly(ethylene oxide)-Lactoselactone 블록공중합체와 이들의 미립자 제조 및 특성)

  • Kim, Young-Hoon;Cho, Chong-Su;Sung, Young-Kiel;Chung, Byung-Ho;Lee, Kang-Choon
    • Journal of Pharmaceutical Investigation
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    • v.22 no.3
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    • pp.237-240
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    • 1992
  • A series of biodegradable block copolymers consisting of $poly({\gamma}-benzyl\;L-glutamate)$ (PBLG) and poly(ethylene oxide) (PEO)-lactoselactone were prepared by polymerization of PEO-lactoselactone and ${\gamma}-benzyl$ L-glutamate-N-carboxyanhydride and characterized by IR and NMR. From circular dichroism measurements, it was found that the polymers exist in the ${\alpha}-helical$ conformation. Block copolymer microspheres were prepared by solvent-extraction-precipitation method for their primary evaluation for medical and biological applications.

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Synthesis of Biodegradable Polymers with Carbon Dioixde (이산화탄소를 이용한 생분해성 고분자의 합성)

  • Shin Sang Chul;Shin Jae Shik;Lee Yoon Rae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.5 no.6
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    • pp.521-525
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    • 2004
  • Biodegradation of poly(ethylene carbonate) (PEC) and their terpolymers has been investigated in vitro. PEC has been synthesized with ethylene oxide (EO) and carbon dioxide, which is one of the greenhouse gases using Zinc glutarate has been used as catalyst Carbonate terpolymers have been prepared by the use of EO, cyclohexene oxide(CHO), and carbon dioxide. High biodegradability of PEC and terpolymers with EO. has been observed. Very low biodegradation of poly(propylene carbonate) (PPC) and poly(cyclohexene carbonate) (PCHC) has been shown. The weight loss, FT-IR and SEM have been employed to characterize biodegradability.

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Sterilization and Quality Changes of Laboratory Rodent Diet by Different Treatments (실험동물 사료의 처리방법별 살균효과와 성분변화)

  • Yang, Jae-Seung;Kwon, Joong-Ho;Byun, Myung-Woo;Cho, Han-Ok
    • Applied Biological Chemistry
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    • v.30 no.2
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    • pp.126-132
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    • 1987
  • The usual sterilization methods such as fumigation and autoclaving of laboratory rodent diet was compared with a new irradiation treatment in the point of sterilization effect and physico-chemical quality. Under the treatments of $10{\sim}20\;kGy$ ${\gamma}-irradiation$ and autoclaving at $121^{\circ}C$ for 20 min, total microorganisms were eliminated but ethylene oxide fumigation was insufficient to destory them. Total amino acid content was reduced about 5% in 20 kGy radiation treatment compared with control, while in the ethylene oxide fumigation and the autoclaving, the reducing rate was markedly great as 15% and 20%, respectively. Total sugar and mineral contents were not significantly different among treatment among treatment groups. TBA values were increased in all treatments. The pH of irradiated group war stable in comparison with that of ethylene oxide. In the treatments of ethylene oxide and especially autoclaving, overall appearance was decreased to a great extent as a result of decreasing lightness and increasing redness.

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Activity test of post-reforming catalyst for removing the ethylene in diesel ATR reformate (디젤 자열개질 가스 내 포함된 $C_2H_4$ 제거를 위한 후개질기 촉매 활성 실험)

  • Yoon, Sang-Ho;Bae, Joong-Myeon;Lee, Sang-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.218-221
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    • 2009
  • Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

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Solubility Study of Graphene-oxide with Various Solvents (산화그래핀(Graphene oxide)의 솔벤트(solvent)별 Solubility에 대한 연구)

  • Jung, Su-Yeon;Choi, Sung-Woong
    • Composites Research
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    • v.35 no.1
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    • pp.18-22
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    • 2022
  • Dispersion is one of the most important factors in the manufacture of composite materials. In the manufacture of composite materials, solvents are used to better disperse the reinforcement, nano-filler in the matrix. Since dispersion is affected with solvents, it is necessary to study which solvent is adopted to get good dispersion. In this study, the dispersion behavior and solubility of graphene oxide(GO) were examined under various solvents (DMF, NMP, ethylene glycol, Acetone, DI water) to identify dispersion. As a result of UV-Vis spectroscopy absorbance measurement, it was found that DMF and ethylene glycol had the best dispersibility, whereas DI water showed the lowest dispersibility. In addition, as a result of visually observing the dispersion according to the surface tension and time, it was found that the dispersibility was excellent in the order of DI water, ethylene glycol, NMP, DMF, and acetone, which was consistent with the Hansen solubility parameter value.