• Title/Summary/Keyword: Korea Environment Institute

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Decomposition of Acetylsalicylic Acid by Gamma Ray (감마선 조사에 의한 Acetylsalicylic Acid의 분해)

  • Ahn, Young Deok;Lee, Kyoung-hwon;Lee, O Mi;Kim, Tae-Hun;Jung, In ha;Yu, SeungHo;Lee, Myun-Joo
    • Journal of Radiation Industry
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    • v.5 no.3
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    • pp.253-258
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    • 2011
  • Acetylsalicylic acid (ASA) has been issued recently in contaminated water environments because of potential impacts on ecosystem and public health. This study was aimed at investigating the possibility of ASA degradation using gamma ray irradiation. In addition, the use of sodium persulfate, hydrogen peroxide, ferrous sulfate were tested in order to examine a synergistic effect with gamma ray. The absorbed dose was ranged from 0.2 to 10 kGy and the concentration of oxidants were from 0.1 to 10 mM in this study. The concentration of ASA was gradually decreased corresponding to the increase of the absorbed dose. When soudium persulfate was simultaneously applied, most of the parent compound was completely degraded even at a low dose of 0.8 kGy. The removal efficiency of total organic carbon was 90% even at the highest dose of 10 kGy without sodium persulfate. However, the efficiency was dramatically enhanced up to 98% at the same dose by adding 10 mM of oxidants. It was suggested that hydroxyl radical ($OH{\cdot}$) and sulfate radical ($SO{_4}^-{\cdot}$) were formed in the system and made roles in degrading ASA at the same time.

Temporal Variations of Total Mercury Concentration in Precipitation: Difference in Source Characteristics between China and Korea

  • Nguyen, Duc Luong;Shim, Shang-Gyoo;Kim, Jin-Young;Jin, Hyoun-Cher;Zhang, Xiao-Shan
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2010.04a
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    • pp.322-326
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    • 2010
  • This study shows that atmospheric TPM concentrations and THg concentrations in precipitation measured in China were higher that those measured in Korea. TPM concentrations and THg concentrations in precipitation during the cold periods were generally higher than those during the warm periods in both China and korea. In China, variations of THg concentration in precipitation during the cold and warm periods were influenced by scavenging of both TPM and RGM. Different from China, in Korea, variations of THg concentration in precipitation during the cold period were also influenced by scavenging of both TPM and RGM; however, those during the warm periods were dominantly governed by scavenging of RGM.

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Characterization of Epoxy Resin Containing Nano Clay Prepared by Electron Beam (전자선에 의해 제조된 나노 clay 함유 에폭시 수지의 특성)

  • Park, Jong-Seok;Lee, Seung-Jun;Lim, Youn-Mook;Jeong, Sung-In;Gwon, Hui-Jeong;Shin, Young-Min;Kang, Phil-Hyun;Nho, Young-Chang
    • Journal of Radiation Industry
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    • v.9 no.1
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    • pp.9-13
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    • 2015
  • Epoxy resin is widely used as aerospace, automobile, construction and electronics due to their good mechanical and electrical properties and environmental advantages. However, the inherent flammability of epoxy resin has limited its application in some field where good flame retardancy is required. Nano clay can enhance the properties of polymers such as flames retardancy and thermal stability. In this study, we have investigated the nanoclay filled epoxy composite, which has good flame retardancy while maintaining high mechanical properties. The cured epoxy resins were obtained using an electron beam curing process. The nano clays were dispersed in epoxy acrylate solution and mechanically stirred. The prepared mixtures were irradiated using an electron beam accelerator. The composites were characterized by gel content and thermal/mechanical properties. Moreover, the flammability of the composite was evaluated by limited oxygen index (LOI). The flame retardancy of nano clay filled epoxy composite was evidently improved.

Radiation Preparation and Characterization of Antimicrobial Hydrogels (방사선 이용 항균성 천연추출물 함유 하이드로겔 제조 및 특성 연구)

  • Gwon, Hui-Jeong;Park, Eun Ji;Choi, Jong-Bae;Lim, Jong-Young;Jeong, Jin-Oh;Shin, Young Min;Jeong, Sung In;Park, Jong-Seok;Lim, Youn-Mook
    • Journal of Radiation Industry
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    • v.7 no.1
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    • pp.87-91
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    • 2013
  • Taraxacum platycarpum (TP) has been used for years without restriction on usual dose for its non-toxic nature and nonexistence of the side effects. To develop antimicrobial hydrogel, poly (vinylalcohol) (PVA) hydrogels containing the aqueous extracted TP as an antimicrobial agent were prepared by using gamma-rays irradiation. The antimicrobial activities of the TP hydrogels were tested against Staphylococcus aureus and Staphylococcus epidermidis by disc diffusion method. The inhibition zones (IZ) of the TP extracts and TP hydrogels against S. aureus were 16 mm and 20 mm and against S. epidermidis was 10 mm and 13 mm, respectively. In conclusion, the TP hydrogel that has an excellent antimicrobial activity was proved to be a valuable material for functional skin care.