• Title/Summary/Keyword: high density polyethylene

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Otoplasty with High Density Polyethylene Implant(MEDPOR®) (잠복이에서 고밀도 폴리에틸렌 삽입물(MEDPOR®)을 이용한 귀성형술)

  • Lee, Keun-Cheol;Kwon, Yong-Seok;Heo, Jung;Moon, Ju-Bong;Kim, Seok-Kwun
    • Archives of Plastic Surgery
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    • v.36 no.2
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    • pp.167-173
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    • 2009
  • Purpose: The key points of treatment of cryptotia are the elevation of invaginated ear helix and the correction of deformed cartilage. Prevention of stabilized cartilage contouring from returning to the previous state is also important. The authors carried otoplasty by modified Onizuka's method or Ohmori's method that conchal cartilage graft or high density polyethylene implant(MEDPOR$^{(R)}$) graft served as fixation after spreading posterior aspect of adhered antihelix and a splint for prevention of recurrence of cartilage deformities. The aim of this study is to reveal the availability of the high density polyethylene implant(MEDPOR$^{(R)}$) graft for the correction of cryptotia. Methods: We have repaired 17 cryptotic deformities using cartilage graft from cavum of concha(12 cases) or high density polyethylene implant(5 cases) for correction of deformed cartilage. We investigate the operative time, complications, and satisfaction of postoperative ear shape on both autogenous cartilage graft group and high density polyethylene implant graft group. Results: There was 1 case of reinvagination on autogenous cartilage graft group. Implant exposure was occurred on high density polyethylene implant graft group, as 1 case. These were statistically no differences between autogenous cartilage graft group and high density polyethylene implant graft group to the satisfaction of ear shape. Conclusion: High density polyethylene implant(MEDPOR$^{(R)}$) present an alternative to autogenous material as they allow of fibrovascular ingrowth, leading to stability of the implant and decreased infection rates. The correction of deformed cartilage by using the high density polyethylene implant(MEDPOR$^{(R)}$) is a good option for the treatment of cryptotia.

Chararcteristics of Water Vapor Transmission in Base Resin for Underground Residential Distribution Power Cable (지중배전케이블 기저수지의 수증기 투과 전달특성)

  • Song, Jae-Joo;Han, Byung-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05b
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    • pp.149-153
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    • 2003
  • In URD(Underground Residential Distribution) power cable, experiments of WVT(Water Vapor Transmission) test on the Base Resin accomplished to specimens which contained CB(Carbon Black), anti-oxidant to base resin and made by pressing to resin of pellet or lump form. a kind of specimens was HDPE(High Density Polyethylene), MDPE(Medium Density Polyethylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). as a results of WVT test, we saw that WVT ratio was HDPE < LLDPE < MDPE≒LDPE${\ll}$ PVC. WVT properties of PVC using for jacket showed properties 15-20 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials.

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Characterization of Water Vapor Transmission & Dielectric Breakdown in Insulation Materials for Jacket Compound (자켓 컴팍운드용 절연재의 수증기투과 및 절연파괴 특성)

  • 송재주;한재홍;송일근;한용희;한병성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.52-56
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    • 2001
  • Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB(Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE> LLDPE = MDP E> LDPE and WVT ratio was HDPE

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On the Pyrolysis of Polymers IV. Pyrolysis of Polythylene and Polypropylene (高分子物質의 熱分解에 關한 硏究 (第4報) Polyethylene 및 Polypropylene의 熱分解에 關하여)

  • Chwa-Kyung Sung;Icksam Noh;Jung Yup Kim;Sung Bong Chang
    • Journal of the Korean Chemical Society
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    • v.7 no.2
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    • pp.122-127
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    • 1963
  • Pyrolysis fo polyethylene and polypropylene has been studied in order to clarify the mechanism of chain scission and effect of oxygen on degradation. Rate of weight decrease was measured under nitrogen and air atmosphere at constant temperature for the samples of high density polyethylene, low density polyethylene and isotactic polypropylene, and then gaseous hydrocarbons produced from pyrolysis were analysed by gas chromatography. Although there is little substantial difference between composition of hydrocarbon gases from pyrolysis of high density polyethylene and low density polyethylene except some difference in quantity of total gas produced, gas composition from polypropylene pyrolysis differs from that of polyethylene pyrolysis. Gases from pyrolysis under air contain much more unsaturated hydrocarbons than those from pyrolysis under inert gas.

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FTIR study of gamma and electron irradiated high-density polyethylene for high dose measurements

  • Al-Ghamdi, Hanan;Farah, Khaled;Almuqrin, Aljawharah;Hosni, Faouzi
    • Nuclear Engineering and Technology
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    • v.54 no.1
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    • pp.255-261
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    • 2022
  • A reliable and well-characterized dosimetry system which is traceable to the international measurement system, is the key element to quality assurance in radiation processing with cobalt-60 gamma rays, X-rays, and electron beam. This is specifically the case for health-regulated processes, such as the radiation sterilization of single use medical devices and food irradiation for preservation and disinfestation. Polyethylene is considered to possess a lot of interesting dosimetric characteristics. In this work, a detailed study has been performed to determine the dosimetric characteristics of a commercialized high-density polyethylene (HDPE) film using Fourier transformed infrared spectrometry (FTIR). Correlations have been established between the absorbed dose and radiation induced infrared absorption in polyethylene having a maximum at 965 cm-1 (transvinylene band) and 1716 cm-1 (ketone-carbonyl band). We have found that polyethylene dose-response is linear with dose for both bands up to1000 kGy. For transvinylene band, the dose-response is more sensitive if irradiations are made in helium. While, for ketone-carbonyl band, the dose-response is more sensitive when irradiations are carried out in air. The dose-rate effect has been found to be negligible when polyethylene samples are irradiated with electron beam high dose rates. The irradiated polyethylene is relatively stable for several weeks after irradiation.

Wet Environmental and Mechanical Characteristics for Polyethylene-based Insulating Materials (Polyethylene 계열 절연재료의 환경적·기계적 특성)

  • Song, Woo-Chang;Choi, Won-Seok;Park, Ha-Yong
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.2
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    • pp.119-123
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    • 2014
  • In this study, four kinds of specimens of PE(polyethylene)-based insulating materials were prepared for selecting the optimum insulation materials in a wet environment. The specimens were tested by various methods, the anti tracking test, the transmittance test in the water vapor transmittance(WVT) and the abrasion resistive test, etc. The HDPE(high-density polyethylene) specimen was showed excellent property in the tracking resistance test and the lowest transmittance in water vapor transmittance test. In the abrasion resistive test, the LLDPE(linear low-density polyethylene) and MDPE(medium-density Polyethylene) were showed excellent mechanical properties. The value of cut-through resistance for MDPE and HDPE were superior to that for LLDPE and LDPE(low-density polyethylene).

Characterization of Water Vapor Transmission & Dielectric Breakdown in Insulation Materials for Jacket Compound (자켓 컴파운드용 절연재의 수증기투과 및 절연파괴 특성)

  • Song, Jae-Joo;Han, Jae-Hong;Song, IL-Keun;Han, Yong-Hee;Han, Byung-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.52-56
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    • 2001
  • Experiments of 2 type on insulating compounds accomplished to change PVC using in URD(Underground) power cable jacketing. one was DB (Dielectric Breakdown) test on the pure base resins and the others were WVT(Water Vapor Transmission) test on the compounds which contained C/B(Carbon Black), anti-oxidant to base resin. a kind of specimens made by pressing to resin of pellet or lump form was HDPE(High Density Polyethylene), MDPE(Medium Density Polyehylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC (Polyvinyl Chloride). As a results of AC DB and WVT test, we saw that strength of Insulation was HDPE > LLDPE ≒ MDPE > LDPE and WVT ratio was HDPE < LLDPE < MDPE < LLDPE ≒ LDPE${\ll}$PVC. WVT of PVC using for jacket showed characteristic 15 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials

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Electrical Properties Low-Density Polyethylene by use of Metallocene Catalyst (메타로센 촉매를 이용한 저밀도 폴리에틸렌의 전기적 특성)

  • ;Tatsuo Mori;Teruyoshi Mizutani
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.123-127
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    • 2000
  • In order to investigate the influence of manufacturing process on the electrical properties, we used two kinds of low density polyethylene prepared using metallocene catalyst (mL), linear low density polyethylene prepared using Ziegler catalyst (LL) and low density polyethylene by high pressure process (LD). mL has the narrowest composition and molecular weight distributions. We measured the dc and impulse breakdown strengths and current densities at 3$0^{\circ}C$, 6$0^{\circ}C$ and 9$0^{\circ}C$. mL had a higher breakdown strength and a lower high-field current than LD and LL. These results were discussed from the point of manufacturing processes.

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Preparation and Characterization of High Density Polyethylene (HDPE)/Exfoliated Graphite (EFG) Nanocomposite Films (High Density Polyethylene (HDPE) / Exfoliated Graphite (EFG) 나노복합필름 제조와 특성에 관한 연구)

  • Kwon, Hyok;Kim, Dowan;Seo, Jongchul
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.19 no.2
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    • pp.95-102
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    • 2013
  • Exfoliated graphite (EFG) with high aspect ratio was incorporated with high density polyethylene (HDPE) for use as high barrier packaging material such as water-sensitivity electric product and pharmaceutical packaging. Also HDPE/EFG nanocomposite films were prepared by adding the compatibilizer for effective dispersion and compatibility. Their chemical properties, crystal structure properties, thermal properties and water barrier properties of as-prepared HDPE/EFG nanocomposite films were investigated as a function of EFG contents. It showed that there is a weak interfacial interaction between HDPE and EFG, however, the water vapor permeations were decreased from 127 to 78 (70 ${\mu}m{\cdot}g/m^2$, $day{\cdot}atm$) by addition of EFG. Especially, the physical properties of HDPE/EFG nanocomposite films were effectively increased up to 0.5 wt%, however, there were no significant improvement of properties in nanocomposite films at the additional EFG loading. To maximize their performance of the nanocomposite films, further research is required to enhance the dispersion of EFG and compatibility of EFG in HDPE matrix.

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