• Title/Summary/Keyword: 폴리에칠렌

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Controlled Drug Release from Polyacrylic Acid-Polyethylene Glycol Interpenetrating Networks (폴리아크릴산-폴리에칠렌글리콜 IPN공중합체 마트릭스의 팽윤 및 약물방출)

  • Kim, Youn-Jung;Kim, Kil-Soo;Lee, Seung-Jin
    • Journal of Pharmaceutical Investigation
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    • v.24 no.4
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    • pp.257-263
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    • 1994
  • The interpenetrating polymer networks (IPNs) of polyacrylic acid (PAA)-polyethylene glycol (PEG) were synthesized via crosslinking of PEG and simultaneous free radical polymerization of PAA. The equilibrium swelling of the IPNs matrices, ranged from 40% to 95%, was varied to a great extent as compared with PAA homopolymer due to the interpolymer interaction between PAA and PEG. The drug release kinetics of drug loaded matrices was significantly affected by the charge of drugs as well as interpolymer complexation.

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The Treeing Deterioration with Prestressed D.C Voltage in Low Density Polyethylen Mixed with Organic Compounds (유기물이 첨가된 저밀도 폴리에칠렌에서 예비과전에 따른 트리잉 열화)

  • 채홍인;양계준;임기조
    • Journal of the Korean Society of Safety
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    • v.6 no.2
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    • pp.15-20
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    • 1991
  • In this paper, we have investigated the effect of organic additives and prestressed D C. voltage on the impulse tree initiation in low density polyethylene. The five klnds of organic compounds was selected for the purpose of inhibiting tree initiation and 10 wt % of each additive was mixed in low density polyethylene. The positive or negative impulse voltage was applied after prestressed D.C. voltage was applied in order to investigate the effect of the space charge influenced on tree initiation. The lengths of tree initiation in case of belng same polarity between prestressed D.C. voltage and impulse voltage were longer than those in case of being different polarity between prestressed D.C. voltage and impulse voltage. When the polarity prestressed D.C. voltage was the different plarity of impulse voltage, the length of tree initiation increased with increasing the prestressed D.C. voltage and decreasing the rest time Among the organic additives used in this paper, the m-cresol can be shown to be the most effective inhibiter to tree initiation.

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An Analysis of Insulating Reliability in Polyethylene for High Frequency Molding Materials (고주파 성형 재료용 폴리에칠렌의 절연 신뢰도 분석)

  • Park, Geon-Ho;Kim, Ki-Joon;Wang, Jong-Bae;Shin, Chul-Ki;Kim, Jin-Sa;Lee, Joon-Ung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.10a
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    • pp.64-67
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    • 2000
  • In this study, the DC dielectric breakdown of polyethylene used for clothing material of cable was experimented and then its data were simulated by Weibull distribution probability. The dielectric breakdown characteristics in polyethylene were examined and various effects of the DC dielectric breakdown on polyethylene were also discussed.

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STUDIES ON THE CHLORINE OF BURLEY TOBACCO PLANTS VI. THE EFFECT OF REMOVAL TIME OF MULCHED POLYETHYLENE FILM ON THE CHLORINE CONTENTS OF SOIL AND TOBACCO LEAVES (버어리종 담배의 염소에 관한 연구 VI. 폴리에칠렌 피복필림 제거시기가 토양과 잎담배의 염소함량에 미치는 영향)

  • 김상범;배길관
    • Journal of the Korean Society of Tobacco Science
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    • v.11 no.1
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    • pp.19-25
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    • 1989
  • Effect of removal time of mulched polyethylene film on the chlorine content of toP soil and on the chlorine absorption by burley tobacco Plants was investigated under the field condition in 1986 and 1987. Treatment consisted of 4 removal times (from 30 to 75 days after transplanting with IS days interval) and control (no removal). The chlorine content of top Boll at 15 days after removal of mulched polyethylene film(MPF) lowered temporarily, and the decrement of chlorine content of top soil was closely related to the sum of rainfalls after removal of MPF. The chlorine was accumulated much in upper leaves when the MPF being removed early, while the chlorine was accumulated much in lower loaves when the MPF being removed late, relatively. However, the removal of MPF had no effect on the chlorine content of whole leaf. The yield decreased with removal of MPF during growing period.

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The Effect of Human Recombinant Superoxide Dismutase Conjugated with Polyethylene Glycol on the Hepatic Toxicity of Acetaminophen (HrSOD-폴리에칠렌 접합체의 아세트아미노펜 간독성에 미치는 영향)

  • Yong, Chul-Soon;Park, Kyong-Ah;Oh, Doo-Man
    • Journal of Pharmaceutical Investigation
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    • v.25 no.4
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    • pp.313-322
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    • 1995
  • The covalent conjugation of human recombinant superoxide dismutase (hrSOD) with trichloros-triazine activated polyethylene glycol (PEG) 5000 formed soluble conjugates with molecular weight of 92KD, which retained $90{\sim}98%$ of original activity with a markedly prolonged plasma half-life of enzyme activity. The effect of hrSOD-PEG conjugates on acetaminophen (ACP)-induced hepatotoxicity was tested in male rats which were pretreated with 3-methylcholanthrene. HrSOD-PEG conjugates inhibited the hepatotoxicity produced by ACP, on the other hand, native hrSOD had no protective effect. The above results indicated that oxygen radicals might participate in the mechanism of the ACP-induced hepatotoxicity and that polymer conjugated-protein drugs with prolonged half-lives could be employed as an effective therapeutic agent.

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Heparin Release from Polyurethane-Polyethylene Oxide-Polypropylene Oxide Device (폴리우레탄-폴리에칠렌옥사이드-폴리프로필렌옥사이드-디바이스로부터의 헤파린 방출)

  • Yoo, Jae-Gwon;Jun, Sung-Joo;Kim, Sung-Ho
    • Journal of Pharmaceutical Investigation
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    • v.18 no.4
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    • pp.169-174
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    • 1988
  • The release of heparin from monolithic devices composed of different ratios of polyethylene oxide-polypropylene oxide (PEO-PPO) and hydrophobic polyurethane was investigated. The release rate of heparin could be controlled by varying the PEO-PPO content. The heparin release rate from the devices increased as the content of PEO-PPO in the devices increased. The release mechanism may be associated with creation of micro-channels and pores through the devices following the change in the physical structure of the polymer network. Hydrophobic polyurethane containing PEO-PPO can provide an antithrombogenic material for prolonged release of heparin from a heparin blended system.

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