• Title, Summary, Keyword: polyethylene

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Effects of Colored Polyethylene Film Mulching on Germination, Emergence, and Growth of Weeds (착색(着色) 폴리에틸렌 필름 멀칭이 잡초(雜草)의 발아(發芽), 발생(發生) 및 생장(生長)에 미치는 영향(影響))

  • Pyon, Jong-Yeong
    • Korean Journal of Weed Science
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    • v.5 no.1
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    • pp.19-23
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    • 1985
  • Soil temperature was higher in clear or blue polyethylene film and bare soil than in black or green polyethylene film and straw mulching. Light transmission was low in black, blue or green colored polyethylene film and straw mulching. Germination of weeds was generally high under clear polyethylene film but black polyethylene film inhibited the germination. Germination of Portulaca oleracea, Setaria viridis and Amaranthus retroflexus increased under blue polyethylene film but inhibition of germination was observed in Erigeron canadensis, Avena fatua, Chenopodium ablum, Digitaria sanguinalis and Echinochloa crusgalli. Green polyethylene film mostly inhibited germination of weeds except A, fatua, C. album and E. canadensis. The greatest number of weeds emerged was obtained in clear polyethylene film, next in bare soil but green or blue polyethylene film inhibited the emergence of weeds. However, no emergence of weeds was observed under black polyethylene film. The highest dry weight of weeds was obtained in clear polyethylene film, next in bare soil, but green or blue polyethylene film and straw mulching caused suppression of weed growth. No weeds were grown under black polyethylene film.

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Enhancement of Dissolution from Pharmaceutical Preparation of Hydrophobic Drugs ( I ) -Characteristics of Sulpiride-Polyethylene Glycol Coprecipitates-

  • Ku, Young-Soon
    • Journal of Pharmaceutical Investigation
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    • v.12 no.4
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    • pp.145-152
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    • 1982
  • Data from IR spectroscopy and X-ray diffractometry were used for the characterization of sulpiride polyethylene glycol coprecipitates related with polymorphism of sulpiride. Sulpiride Form II transformed to Form I during coprecipitating with polyethylene glycol and the transformation rate is increased in proportion to molecular size of polyethylene glycol and the content of polyethylene glycol in coprecipitate.

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A Study on the Improvement of Adhesive Strength of Between Metal and Polyethylene Materials (금속재와 폴리에틸렌 재료간의 접착강도 향상에 대한 연구)

  • Lee, Ji-Hoon;Kim, Hyun-Ju;Jung, Dong-Ho;Rhee, Kyong-Yop
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.12
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    • pp.143-148
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    • 2007
  • Polyethylene is a typical hydrophobic material and it is difficult to bond the polyethylene material with metal material. Thus, it is important to modify the surface of polyethylene material to improve the bonding strength between the polyethylene and the metal materials. In this study, the surface modification of polyethylene material was investigated to improve the interfacial strength between the polyethylene and the steel materials. Polyethylene material was surface-modified in a plasma cleaner using an oxygen gas. Two cases of composites (surface-modified pelyethylene/steel composite and regular (as-received) pelyethylene/steel composite) were fabricated using a secondary bonding method. Shear and bending tests have been performed using the two cases of composites. The results showed that the contact angle did not change much as the modification time increased. However, the contact angle decreased from ${\sim}76^{\circ}\; to\;{\sim}41^{\circ}$ with the modification. The results also showed that the shear strength and the bending strength were improved about 3030 % and 7 %, respectively when the polyethylene was plasma-modified using an oxygen gas.

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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    • 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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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).

Applications of Irradiation to Polyethylene for Flame Retarded Wire and Cable Insulation (방사선에 의한 폴리에칠렌의 난연성전선 및 케이블에 관한 연구)

  • Young Kun Kong;Hoon Seun Chang;Chong Kwang Lee;Jae Ho Choi
    • Nuclear Engineering and Technology
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    • v.13 no.4
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    • pp.245-253
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    • 1981
  • The properties of polyethylene materials exhibit good insulation and radiation resistance, but exhibit poor flame resistance. Flame retardant properties of the polyethylene were improved by the radiation induced grafting or crosslinking. When the various flame retardants were fixed onto polyethylene, the amount of fixation in grafting was increased with the increase of radiation dosages. In the case of grafting, it is necessary for high grafting yield that the polyethylene films were swelled before irradiation with ${\gamma}$-rays or electron beams. It is the suitable method for the fixation of flame retardant that polyethylene samples were blended with various flame retardants at 1$25^{\circ}C$ and then blended polymers were crosslinked by the electron beams at room temperature.

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Thermal Durability Analysis Due to Material of Radiator Fan (라디에이터 팬의 재질에 따른 열 내구성 해석)

  • Han, Moonsik;Cho, Jaeung
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.22 no.5
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    • pp.789-794
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    • 2013
  • In this study, the temperature, heat emission per unit time, and thermal stress or deformation of a radiator fan made of polyethylene or aluminum are analyzed for investigating its strength durability. Heat transfer in the case of the aluminum radiator fan is better than that in the case of the polyethylene radiator fan. Further, heat emission in the case of the aluminum fan is poorer than that in the case of the polyethylene fan. Moreover, because the thermal deformation of aluminum is much smaller than that of polyethylene, the thermal durability of the aluminum fan is better than that of the polyethylene fan. In an open space in front of the radiator and the closed space of the engine behind it, the thermal cooling effect of the polyethylene fan is better than that of the aluminum fan. Further, since polyethylene is lighter in weight than aluminum, polyethylene, as a nonmetallic plastic, is more suitable as a material of an automotive radiator. However, because of the higher strength durability of the aluminum fan, it is better than the polyethylene fan under high-temperature conditions or in the case of a complex pipe.

A Yew Technique for Infrared Spectroscopy using Polyethylene Film Cell (Polyethylene Film을 利用한 赤外線分光分析用 Cell)

  • Sung, Chwa-Kyung;Noh, Ick-Sam
    • Journal of the Korean Chemical Society
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    • v.7 no.1
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    • pp.58-64
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    • 1963
  • Authors propose a new technique using polyethylene film instead of sodium chloride window as a cell material. Nujol mulls, liquids and aqueous solutions are sandwitched between two pieces of polyethylene film which are held between cardboards. Ordinary lead or stainless steel spacers could be used if exact cell thickness is desired. A more elaborate cell can be assembled by injecting samples between two pieces of polyethylene film which are placed between sodium chloride windows of ordinary demountable liquid cell. The absorption bands due to polyethylene and Nujol are compensated by placing the polyethylene film of suitable thickness in the reference beam. The absorption bands due to solvents such as water can also be compensated by the polyethylene film cell sandwitched solvent of suitable thickness in the reference beam. This method would be a simple new technique. Especially this technique may offer a new helpful way for the investigation of the state of substances in aqueous system. Using this technique, authors have observed the appearance of an absorption bands at 3.2 micron, in the spectrum of phenol in aqueous solution, that is absent in the spectrum of phenol in benzene solution. The same absorption band also has been observed in the spectra of aqueous formaldehyde solution and aqueous polyvinyl alcohol solution, where the absorption bands due to polyethylene and water are compensated. Although it may be regarded that this absorption band is related to the intermolecular interaction between water and the solute having OH group, that is hydrogen bonding. The exact assignment of this absorption band is out of this work.

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High Pressure Phase Behavior in the Binary Polyethylene/Butane and Polyethylene/Dimethyl Ether Systems (이성분 폴리에틸렌/부탄과 폴리에틸렌/디메틸 에테르계의 고압 상거동)

  • Jeon, Nam-Seok;Byun, Hun-Soo
    • Applied Chemistry for Engineering
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    • v.10 no.5
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    • pp.761-766
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    • 1999
  • In this paper, high pressure phase behavior in the binary polyethylene/butane and polyethylene/dimethyl ether has been studied. The pressure-temperature diagrams in polyethylene/butane were shown by increasing concentration for molecular weight standards, that is, $M_w=700,\;1000$ and 2000. It is found that the temperature and the pressures go up with increasing in concentrations for each molecular weight, but the latter lower in concentrations over 16 wt % polyethylene. In addition, the phase behaviors for each molecular weights with about 5 wt % polyethylene are shown in pressure-temperature, and pressures increase with increasing in molecular weight($M_w=700,\;1000$, and 2000). The phase behaviors in polyethylene/dimethyl ether are determined according to its molecular weight, and are shown for a range of pressures of 40~280 bar and temperatures of about $120{\sim}220^{\circ}C$. It is shown that in pressure-temperature of polyethylene/dimethyl ether the pressure increases with increasing in polyethylene molecular weight, and the difference in pressure for each molecular weight shows by about 60 bar. The gap in pressure between polyethylene/butane and polyethylene/dimethyl ether system with 5 wt % polyethylene for each molecular weight standards indicates about 25(700), 90(1000), and 100 bar(2000), respectively.

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Development of Thermal Storage System in Plastic Greenhouse (I) -Development of Air-Water Heat Exchange System- (플라스틱 온실(溫室)의 열저장(熱貯藏) 시스템 개발(開發)에 관(關)한 연구(硏究)(I) -수막식(水膜式) 열교환(熱交換) 시스템의 개발(開發)-)

  • Kim, Y.H.;Koh, H.K.;Kim, M.K.
    • Journal of Biosystems Engineering
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    • v.15 no.1
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    • pp.14-22
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    • 1990
  • For efficient use of solar energy in plastic greenhouse, thermal storage system was developed. The system was constructed with the counter-flow type air-water heat exchanger using a thin polyethylene film as a medium of heat exchange parts. Experiments were carried out to investigate the heat exchange rate, optimum water flow rate, overall heat transfer coefficient, and the effectiveness of the counter-flow type air-water heat exchanger with polyethylene film bags. Mathematical model to predict air temperature leaving heat exchanger was developed. The results obtained in the present study are summarized as follows. 1. Heat exchange rate in the counter-flow type air-water heat exchanger with polyethylene film bags was compared to that of polyethylene film. Heat exchange rate was almost identical at air velocity of 0.5m/s on polyethylene film surface. But, heat exchange rate of heat exchanger with polyethylene film bag was $32{\sim}55KJ/m^2$ hr higher than that of polyethylene film at air velocity of 1.0m/s. 2. Considering the formation of uniform water film and the sufficient heat exchange rate of polyethylene film bags, optimum water flow rate in polyethylene film bags was $3.0{\sim}6.0{\ell}/m^2$ min. 3. The overall heat transfer coefficient of polyethylene film bags was found to be $35.0{\sim}130.0KJ/m^2\;hr\;^{\circ}C$ corresponding to the air velocity ranging 0.5 to 4.0 m/s on polyethylene film surface. And the overall heat transfer coefficient showed almost linearly increasing tendency to the variation of air velocity. 4. Mathematical model to predict air temperature leaving the heat exchanger was developed, resulting in a good agreement between the experimental and predicted values. But, the experimental results were a little lower than predicted. 5. Effectiveness of heat exchanger for the experiment was found to be 0.40~0.81 corresponding to the number of transfer units due to the variation of air velocity ranging 0.6 to 1.7 m/s.

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